WorldWideScience

Sample records for carbon tetrafluoride mixtures

  1. Investigation on critical breakdown electric field of hot sulfur hexafluoride/carbon tetrafluoride mixtures for high voltage circuit breaker applications

    Science.gov (United States)

    Wang, Weizong; Murphy, Anthony B.; Rong, Mingzhe; Looe, Hui M.; Spencer, Joseph W.

    2013-09-01

    Sulfur hexafluoride (SF6) gas, widely used in high-voltage circuit breakers, has a high global warming potential and hence substitutes are being sought. The use of a mixture of carbon tetrafluoride (CF4) and SF6 is examined here. It is known that this reduces the breakdown voltage at room temperature. However, the electrical breakdown in a circuit breaker after arc interruption occurs in a hot gas environment, with a complicated species composition because of the occurrence of dissociation and other reactions. The likelihood of breakdown depends on the electron interactions with all these species. The critical reduced electric field strength (the field at which breakdown can occur, relative to the number density) of hot SF6/CF4 mixtures corresponding to the dielectric recovery phase of a high voltage circuit breaker is calculated in the temperature range from 300 K to 3500 K. The equilibrium compositions of hot SF6/CF4 mixtures under different mixing fractions were determined based on Gibbs free energy minimization. Full sets of improved cross sections for interactions between electrons and the species present are presented. The critical reduced electric field strength of these mixtures was obtained by balancing electron generation and loss mechanisms. These were evaluated using the electron energy distribution function derived from the Boltzmann transport equation under the two-term approximation. The result indicates that critical electric field strength decreases with increasing heavy-particle temperature from 1500 to 3500 K. Good agreement was found between calculations for pure hot SF6 and pure hot CF4 and experimental results and previous calculations. The addition of CF4 to SF6 was found to increase the critical reduced electric field strength for temperatures above 1500 K, indicating the potential of replacing SF6 by SF6/CF4 mixtures in high-voltage circuit breakers.

  2. The Reactions of Hot Fluorine-18 with Gaseous Carbon Tetrafluoride

    International Nuclear Information System (INIS)

    Studies on the reactions of hot Fie atoms with carbon tetrafluoride are reported. Gaseous samples were exposed to the 40-60 MeV (maximum) bremsstrahlung beam of the Yale University Electron Accelerator. The F19 (γ, n) F18 process produces F18 with a kinetic energy of the order of 105-106 eV. These species lose energy by collision and are expected to reach the ''chemical'' energy range (18 atoms. Analysis of products was made using standard radio-gas chromatography techniques. The system was found to be quite sensitive to extraneous radiation damage effects and appropriate precautions were taken. Hot displacement reactions, similar to those observed for hot hydrogen, but much less efficient, were found: F18 + CF4 --> CF3F18 + F, F18 +CF4 --> CF2F18 + (F + F), It was impossible to study the abstraction reaction F18 + CF4 --> CF3 + FF18 directly. However, indirect evidence suggests that it also has a low efficiency. Detailed studies of the effect of moderator on the F18 + CF4 system have been made. The data obtained were analysed by means of the kinetic theory of hot reactions. The system was found to be in accord with this formalism, providing quantitative confirmation of the present interpretation of the results. The carbon tetrafluoride and methane systems provide a basis for some tentative conclusions on the mechanisms of hot fluorine atom reactions. At present it appears that with certain important, but natural, modifications the model first developed for hot hydrogen atoms is applicable

  3. Fragment ion-photon coincidence investigation of carbon tetrafluoride by controlled electron impact

    International Nuclear Information System (INIS)

    Fragment ion-photon coincidence (FIPCO) spectra by 120 eV electron impact on carbon tetrafluoride (CF4) have been observed, in which optical emission in the 200-600 nm region has been detected. Only the CF3+ fragment has been found in the FIPCO spectra, demonstrating that the dissociative double-ionization process producing a pair of CF3+ and F+ is negligible in the correlation with the optical emission. This finding was already known from photon-impact experiments, but such a process was expected to play an important role in the ultraviolet-visible emission by electron impact on CF4. The translational energy distribution of CF3+ has also been estimated on the basis of the high-resolution FIPCO spectra and their Monte Carlo simulation. The magnitude of the mean translational energy of CF3+ has been explained together with earlier results obtained through threshold photoelectron-photoion coincidence experiments by considering the Franck-Condon region in the transition among the neutral ground state of CF4 and its ionic A, C and D states. (author)

  4. Effect of titanium tetrafluoride and amine fluoride treatment combined with carbon dioxide laser irradiation on enamel and dentin erosion

    OpenAIRE

    Wiegand, A.; Magalhães, A C; Navarro, R S; Schmidlin, P R; Rios, D.; Buzalaf, M.A.R.; Attin, T.

    2010-01-01

    OBJECTIVE: This in vitro study aimed to analyze the influence of carbon dioxide (CO(2)) laser irradiation on the efficacy of titanium tetrafluoride (TiF(4)) and amine fluoride (AmF) in protecting enamel and dentin against erosion. METHODS: Bovine enamel and dentin samples were pretreated with carbon dioxide (CO(2)) laser irradiation only (group I), TiF(4) only (1% F, group II), CO(2) laser irradiation before (group III) or through (group IV) TiF(4) application, AmF only (1% F, group V), or CO...

  5. United Kingdom experience of uranium tetrafluoride production

    International Nuclear Information System (INIS)

    Uranium tetrafluoride, the key intermediate in the production of uranium hexafluoride and uranium metal, has been produced for more than 35 years at the Springfields Works of British Nuclear Fuels Limited. A brief summary of the background history of UF4 production at Springfields is given, together with a description of the present manufacturing route employing rotary kilns. Comments are included on some safety issues involved

  6. Spectrographic determination of impurities in uranium tetrafluoride

    International Nuclear Information System (INIS)

    A carrier distillation method for the determination of Ag, Al, As, B, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Si in uranium tetrafluoride was develop ped. the previous addition of 25% Y23 prevents the excitation of uranium by conversion of the volatile UF4 into U308 during the arc discharge. NaCl or Ga203, containing Ge and V as internal standards, are used as carriers, and samples are arced in 10 Amp. d.c. arc in a graphite anode cup. 7 mm diameter, 10 mm deep, being the weight of charge 300 mg. (Author) 14 refs

  7. Standardisation of gas mixtures for estimating carbon monoxide transfer factor.

    OpenAIRE

    Kendrick, A. H.; Laszlo, G.

    1993-01-01

    BACKGROUND--The American Thoracic Society recommends that the inspired concentration used for the estimation of carbon monoxide transfer factor (TLCO) mixture should be 0.25-0.35% carbon monoxide, 10-14% helium, 17-21% oxygen, balance nitrogen. Inspired oxygen influences alveolar oxygen and hence carbon monoxide uptake, such that transfer factor increases by 0.35% per mm Hg decrease in alveolar oxygen. To aid in the standardisation of TLCO either a known inspired oxygen concentration should b...

  8. Molecular dynamics simulations of a lithium/sodium carbonate mixture.

    Science.gov (United States)

    Ottochian, Alistar; Ricca, Chiara; Labat, Frederic; Adamo, Carlo

    2016-03-01

    The diffusion and ionic conductivity of Li x Na1-x CO3 salt mixtures were studied by means of Molecular Dynamics (MD) simulations, using the Janssen and Tissen model (Janssen and Tissen, Mol Simul 5:83-98; 1990). These salts have received particular attention due to their central role in fuel cells technology, and reliable numerical methods that could perform as important interpretative tool of experimental data are thus required but still lacking. The chosen computational model nicely reproduces the main structural behaviour of the pure Li2CO3, Na2CO3 and K2CO3 carbonates, but also of their Li/K and Li/Na mixtures. However, it fails to accurately describe dynamic properties such as activation energies of diffusion and conduction processes, outlining the need to develop more accurate models for the simulation of molten salt carbonates. PMID:26897519

  9. Radiation induced chemical reaction of carbon monoxide and hydrogen mixture

    International Nuclear Information System (INIS)

    Previous studies of radiation induced chemical reactions of CO-H2 mixture have revealed that the yields of oxygen containing products were larger than those of hydrocarbons. In the present study, methane was added to CO-H2 mixture in order to increase further the yields of the oxygen containing products. The yields of most products except a few products such as formaldehyde increased with the addition of small amount of methane. Especially, the yields of trioxane and tetraoxane gave the maximum values when CO-H2 mixture containing 1 mol% methane was irradiated. When large amounts of methane were added to the mixture, the yields of aldehydes and carboxylic acids having more than two carbon atoms increased, whereas those of trioxane and tetraoxane decreased. From the study at reaction temperature over the range of 200 to 473 K, it was found that the yields of aldehydes and carboxylic acids showed maxima at 323 K. The studies on the effects of addition of cationic scavenger (NH3) and radical scavenger (O2) on the products yields were also carried out on the CO-H2-CH4 mixture. (author)

  10. Slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures

    Science.gov (United States)

    Aines, Roger D.; Bourcier, William L.; Viani, Brian

    2013-01-29

    A slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures includes the steps of dissolving the gas mixture and carbon dioxide in water providing a gas, carbon dioxide, water mixture; adding a porous solid media to the gas, carbon dioxide, water mixture forming a slurry of gas, carbon dioxide, water, and porous solid media; heating the slurry of gas, carbon dioxide, water, and porous solid media producing steam; and cooling the steam to produce purified water and carbon dioxide.

  11. In-pore exchange and diffusion of carbonate solvent mixtures in nanoporous carbon

    Science.gov (United States)

    Alam, Todd M.; Osborn Popp, Thomas M.

    2016-08-01

    High resolution magic angle spinning (HRMAS) 1H NMR spectroscopy has been used to resolve different surface and in-pore solvent environments of ethylene carbonate (EC) and dimethyl carbonate (DMC) mixtures absorbed within nanoporous carbon (NPC). Two dimensional (2D) 1H HRMAS NMR exchange measurements revealed that the inhomogeneous broadened in-pore resonances have pore-to-pore exchange rates on the millisecond timescale. Pulsed-field gradient (PFG) NMR diffusometry revealed the in-pore self-diffusion constants for both EC and DMC were reduced by up to a factor of five with respect to the diffusion in the non-absorbed solvent mixtures.

  12. Uranium tetrafluoride thermophysical properties measurements by the laser flash method

    International Nuclear Information System (INIS)

    In order to increase the efficiency of the metalothermic reduction process employed by the IPEN - Instituto de Pesquisas Energeticas e Nucleares, to produce metallic uranium by means of uranium tetrafluoride reduction with magnesium, is planned utilize a mathematical model that numerically simulates the heat distribution in the charge of powders of uranium tetrafluoride and metallic magnesium duly blended. Because this program requires as input data the thermal conductivity of the uranium tetrafluoride powder and this data was not found in the literature, pellets were produced by uniaxially pressing the uranium tetrafluoride powder in pellets, employing the same technology developed at CDTN-Centro de Desenvolvimento da Tecnologia Nuclear, to produce nuclear fuel pellets. The thermophysical properties of these pellets were measured at the LMPT - Laboratorio de Medicao de Propriedades Termofisicas de Combustiveis Nucleares e Materiais of CDTN applying the laser flash method. From the measurements results, it was possible to obtain an extrapolated value of ca. 0.24 W.m-1.K-1 for the thermal conductivity of the UF4 powder sample in the loose state and at room temperature. This value will be employed as input data of the mathematical model, whose results will be subject of a future publication. The UF4 powder pelletizing parameters and the thermophysical properties results (density, thermal diffusivity and thermal conductivity), are reported. (author)

  13. Phase transition of carbonate solvent mixture solutions at low temperatures

    Science.gov (United States)

    Okumura, Takefumi; Horiba, Tatsuo

    2016-01-01

    The phase transition of carbonate solvent mixture solutions consisting of ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and LiPF6 salt have been studied for improving the low temperature performance of lithium-ion batteries. The Li ion conductivity at 25 °C was maximum at x = 0.3 in a series of 1 M LiPF6 mixed carbonate solvents compositions consisting of ECxDMC0.5-0.5xEMC0.5-0.5x (x = 0 to 0.6), while the maximum tended to shift to x = 0.2 as the temperature lowered. The differential scanning calorimetry results showed that the freezing temperature depressions of EC in the 1 M LiPF6 solution were larger than those of the DMC or EMC. The chemical shift of 7Li nuclear magnetic resonance changed from a constant to increasing at around x = 0.3, which could be reasonably understood by focusing on the change in solvation energy calculated using Born equation. However, in the region of a high EC concentration of over x = 0.3 (EC/LiPF6 > 4) in the 1 M LiPF6 solution, the free EC from the solvation to the lithium ions seems to reduce the freezing temperature depression of the EC, and thus, decreases the ionic conductivity of the solution at low temperatures, due to the EC freezing.

  14. Catalytic Formation of Propylene Carbonate from Supercritical Carbon Dioxide/Propylene Oxide Mixture

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Propylene carbonate was synthesized from supercritical carbon dioxide (SC-CO2)/ propylene oxide mixture with phthalocyaninatoaluminium chloride (ClAlPc)/ tetrabutylammon-ium bromide (n-Bu4NBr) as catalyst. The high rate of reaction was attributed to rapid diffusion and the high miscibility of propylene oxide in SC-CO2 under employed conditions. Various reaction periods present different formation rate of propylene carbonate, mainly due to the existence of phase change during the reaction. The experimental results demonstrate that SC-CO2 could be used as not only an environmentally benign solvent but also a carbon precursor in synthesis.

  15. Critical temperatures and pressures of reacting mixture in synthesis of dimethyl carbonate with methanol and carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    Xing Cui Guo; Zhang Feng Qin; Guo Fu Wang; Jian Guo Wang

    2008-01-01

    Critical temperatures and pressures of nominal reacting mixture in synthesis of dimethyl carbonate (DMC)from methanol and carbon dioxide(quaternary mixture of carbon dioxide+methanol+water+DMC)were measured using a high-pressure view cell.The results suggested that the critical properties of the reacting mixture depended on the reaction extent as well as its initial composition(initial ratio of carbon dioxide to methanol).Such information is essential for determining the reaction conditions when one intends to carry out the synthesis of DMC with CO2 and methanol under supercritical conditions.

  16. Development of a new gas sensor for binary mixtures based on the permselectivity of polymeric membranes. Application to carbon dioxide/methane and carbon dioxide/helium mixtures

    OpenAIRE

    Rosa Rego; Nídia Caetano; Adélio Mendes

    2004-01-01

    Membrane-based gas sensors were developed and used for determining the composition on bi-component mixtures in the 0100% range, such as oxygen/nitrogen and carbon dioxide/methane (biogas). These sensors are low cost and are aimed at a low/medium precision market.The paper describes the use of this sensor for two gas mixtures: carbon dioxide/methane and carbon dioxide/helium. The membranes used are poly(dimethylsiloxane) (PDMS) and Teflon-AF hollow fibers. The response curves for both sensors ...

  17. Mixture

    Directory of Open Access Journals (Sweden)

    Silva-Aguilar Martín

    2011-01-01

    Full Text Available Metals are ubiquitous pollutants present as mixtures. In particular, mixture of arsenic-cadmium-lead is among the leading toxic agents detected in the environment. These metals have carcinogenic and cell-transforming potential. In this study, we used a two step cell transformation model, to determine the role of oxidative stress in transformation induced by a mixture of arsenic-cadmium-lead. Oxidative damage and antioxidant response were determined. Metal mixture treatment induces the increase of damage markers and the antioxidant response. Loss of cell viability and increased transforming potential were observed during the promotion phase. This finding correlated significantly with generation of reactive oxygen species. Cotreatment with N-acetyl-cysteine induces effect on the transforming capacity; while a diminution was found in initiation, in promotion phase a total block of the transforming capacity was observed. Our results suggest that oxidative stress generated by metal mixture plays an important role only in promotion phase promoting transforming capacity.

  18. A Study on Reactions of Carbon-Carbonate Mixture at Elevated Temperature : As an Anode Media of SO-DCFC

    International Nuclear Information System (INIS)

    A direct carbon fuel cell (DCFC) generates electricity directly by converting the chemical energy in coal. In particular, a DCFC system with a solid oxide electrolyte and molten carbonate anode media has been proposed by SRI. In this system, however, there are conflicting effects of temperature, which enhances the ion conductivity of the solid electrolyte and reactivity at the electrodes while causing a stability problem for the anode media. In this study, the effect of temperature on the stability of a carbon-carbonate mixture was investigated experimentally. TGA analysis was conducted under either nitrogen or carbon dioxide ambient for Li2 CO3, K2 CO3, and their mixtures with carbon black. The composition of the exit gas was also monitored during temperature elevation. A simplified reaction model was suggested by considering the decomposition of carbonates and the catalyzed Boudouard reactions. The suggested model could well explain both the measured weight loss of the mixture and the gas formation from it

  19. Dielectric constants of binary mixtures of propylene carbonate with dimethyl carbonate and ethylene carbonate from molecular dynamics simulation: comparison between non-polarizable and polarizable force fields

    Science.gov (United States)

    Lee, Sanghun; Park, Sung Soo

    2013-01-01

    Using non-polarizable and polarizable molecular dynamics simulations, binary mixtures of propylene carbonate + dimethyl carbonate and propylene carbonate + ethylene carbonate with various compositions were investigated. The polarizable model produces more reasonable estimation of dielectric constants than the non-polarizable model; however, combining the electronic continuum model with the non-polarizable MD improves the comparison between the two models. Fair agreement was found between the results from these simulations and available experimental data. In addition, for a better understanding of the mixing behaviour, the excess dielectric constants over the entire composition were calculated. By comparison of the two mixtures in various mole fractions, distinctive mixing behaviours of propylene carbonate + dimethyl carbonate (poorly symmetric mixture) and propylene carbonate + ethylene carbonate (highly symmetric mixture) were observed.

  20. Further details concerning the radiolysis of a carbon tetrachloride-benzene mixture (1961)

    International Nuclear Information System (INIS)

    The neutron-activation estimation of the chlorine fixed on DPPH during radiolysis of the mixture C6H6-CCl4 makes it possible to evaluate the contribution of the carbon tetrachloride to the overall phenomenon. (authors)

  1. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D

    2015-03-31

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  2. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.

    2013-03-12

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  3. Thermodynamic diagrams for high temperature plasmas of air, air-carbon, carbon-hydrogen mixtures, and argon

    CERN Document Server

    Kroepelin, H; Hoffmann, K-U

    2013-01-01

    Thermodynamic Diagrams for High Temperature Plasmas of Air, Air-Carbon, Carbon-Hydrogen Mixtures, and Argon provides information relating to the properties of equilibrium gas plasmas formed from hydrocarbons, from air without argon, from pure argon, and from mixtures of air and carbon at various compositions, temperatures and pressures. The data are presented in graphical rather than tabular form to provide a clearer picture of the plasma processes investigated. This book is composed of four chapters, and begins with the introduction to the characteristics of plasmas, with emphasis on their th

  4. Therapeutic effect of carbonate buffer mixture on gastrointestinal atony in cattle

    Institute of Scientific and Technical Information of China (English)

    Yu Yi Li; Nai Sheng Zhang; Ze Wang; Zi Jun Yang

    2000-01-01

    AIM To substantiate the therapeutic effects of carbonate buffer mixture on naturally occurringgastrointestinal atony in cattle.METHODS Therapeutic effects of carbonate buffer mixture (Na2CO350 g, NaHCO3420 g, KCI 20 g, NaC1100 g, water 10 L) were observed in 120 cases of gastrointestinal atony including forestomach atony, rumenimpaction, rumen acidosis, omasum impaction and intestinal constipation. Judgement of curative effects ascure: after treated, the cases become clinically normal in general conditions, appetite, rumination, ruminalperistalsis and defecation; uncure: after giving two doses, the gasto-intestinal atony has not been eliminated.RESULTS Average cure rate of carbonate buffer mixture on above-mentioned diseases were 95%, andaverage dose was 1.4±0.5.CONCLUSION Being a new approach for treatment of gastrointestinal atony in ruminants, the carbonatebuffer mixture can eliminate the gastrointestinal atony originated from the over acidity in gastrointestinalcanal.

  5. Role of titanium tetrafluoride (TiF4) in conservative dentistry: A systematic review

    OpenAIRE

    Pragya Wahengbam; Tikku, A. P.; Wahengbam Bruce Lee

    2011-01-01

    The role of fluoride to reduce demineralization and enhance remineralization of dental hard tissue has been well documented. Different forms of fluoride solutions have been topically used in dentistry as prophylactic agents against tooth decay. In the recent past, metal fluorides, especially titanium tetrafluoride, have become popular in the fraternity of dental research due to their unique interaction with dental hard tissue. Many studies on titanium tetrafluoride, with positive and negative...

  6. [Estimation of Hunan forest carbon density based on spectral mixture analysis of MODIS data].

    Science.gov (United States)

    Yan, En-ping; Lin, Hui; Wang, Guang-xing; Chen, Zhen-xiong

    2015-11-01

    With the fast development of remote sensing technology, combining forest inventory sample plot data and remotely sensed images has become a widely used method to map forest carbon density. However, the existence of mixed pixels often impedes the improvement of forest carbon density mapping, especially when low spatial resolution images such as MODIS are used. In this study, MODIS images and national forest inventory sample plot data were used to conduct the study of estimation for forest carbon density. Linear spectral mixture analysis with and without constraint, and nonlinear spectral mixture analysis were compared to derive the fractions of different land use and land cover (LULC) types. Then sequential Gaussian co-simulation algorithm with and without the fraction images from spectral mixture analyses were employed to estimate forest carbon density of Hunan Province. Results showed that 1) Linear spectral mixture analysis with constraint, leading to a mean RMSE of 0.002, more accurately estimated the fractions of LULC types than linear spectral and nonlinear spectral mixture analyses; 2) Integrating spectral mixture analysis model and sequential Gaussian co-simulation algorithm increased the estimation accuracy of forest carbon density to 81.5% from 74.1%, and decreased the RMSE to 5.18 from 7.26; and 3) The mean value of forest carbon density for the province was 30.06 t · hm(-2), ranging from 0.00 to 67.35 t · hm(-2). This implied that the spectral mixture analysis provided a great potential to increase the estimation accuracy of forest carbon density on regional and global level. PMID:26915200

  7. Evaluation of an Industrial Byproduct Glycol Mixture as a Carbon Source for Denitrification

    OpenAIRE

    Liang, Wei

    2013-01-01

    In order to meet increasingly stringent total nitrogen limits, supplemental carbon must be added to improve the performance of the biological nutrient removal process. An industrial by-product that contained ethylene glycol and propylene glycol was used as a substitute carbon source for methanol in this study. The objectives of this study were to investigate the efficiency of using the glycol mixture as carbon source, including the calculation of denitrification rate and yield at two differen...

  8. Ion solvation in propylene carbonate and its mixtures with water and methanol

    International Nuclear Information System (INIS)

    Solvodynamic radii and solvation numbers of some ions (including I-) in propylene carbonate as well as their solvodynamic radii in mixtures of propylene carbonate-water and propylene carbonate-methanol were determined. Effect of medium components and solvated ion characteristics on the process of ion solvation was considered. It is shown that small size anions in propylene carbonate are weakly solvated, whereas bulky lightly polarized anions interact strongly with the solvent. Addition of water or methanol to propylene carbonate leads to intensification of ion solvation

  9. Corrosion of stainless and carbon steels in molten mixtures of industrial nitrates

    Energy Technology Data Exchange (ETDEWEB)

    Goods, S.H.; Bradshaw, R.W. [Sandia National Labs., Livermore, CA (United States); Prairie, M.R.; Chavez, J.M. [Sandia National Labs., Albuquerque, NM (United States)

    1994-03-01

    Corrosion behavior of two stainless steels and carbon steel in mixtures of NaNO{sub 3} and KNO{sub 3} was evaluated to determine if impurities found in commodity grades of alkali nitrates aggravate corrosivity as applicable to an advanced solar thermal energy system. Corrosion tests were conducted for 7000 hours with Types 304 and 316 stainless steels at 570C and A36 carbon steel at 316C in seven mixtures of NaNO{sub 3} and KNO{sub 3} containing variations in impurity concentrations. Corrosion tests were also conducted in a ternary mixture of NaNO{sub 3}, KNO{sub 3}, and Ca(NO{sub 3}){sub 2}. Corrosion rates were determined by descaled weight losses while oxidation products were examined by scanning electron microscopy, electron microprobe analysis, and X-ray diffraction. The nitrate mixtures were periodically analyzed for changes in impurity concentrations and for soluble corrosion products.

  10. Investigation of Binary Mixtures Containing 1-Ethyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)azanide and Ethylene Carbonate

    OpenAIRE

    Hofmann, A.; Migeot, M.; Hanemann, T.

    2016-01-01

    Temperature dependent viscosity, conductivity, and density data of binary mixtures containing ethylene carbonate (EC) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)azanide (EMIM-TFSA) were determined at atmospheric pressure in a wide temperature range of (20 to 120) °C. Additionally, differential scanning calorimetry (DSC) measurements were performed from (−120 to +100) °C to characterize phase behavior of the mixtures. On the basis of the experimental data it is demonstrated t...

  11. Increased plant carbon translocation linked to overyielding in grassland species mixtures.

    Directory of Open Access Journals (Sweden)

    Gerlinde B De Deyn

    Full Text Available Plant species richness and productivity often show a positive relationship, but the underlying mechanisms are not fully understood, especially at the plant species level. We examined how growing plants in species mixture influences intraspecific rates of short-term carbon (C- translocation, and determined whether such short-term responses are reflected in biomass yields. We grew monocultures and mixtures of six common C3 grassland plant species in outdoor mesocosms, applied a (13C-CO(2 pulse in situ to trace assimilated C through plants, into the soil, and back to the atmosphere, and quantified species-specific biomass. Pulse derived (13C enrichment was highest in the legumes Lotus corniculatus and Trifolium repens, and relocation (i.e. transport from the leaves to other plant parts of the recently assimilated (13C was most rapid in T. repens grown in 6-species mixtures. The grass Anthoxanthum odoratum also showed high levels of (13C enrichment in 6-species mixtures, while (13C enrichment was low in Lolium perenne, Plantago lanceolata and Achillea millefolium. Rates of C loss through respiration were highest in monocultures of T. repens and relatively low in species mixtures, while the proportion of (13C in the respired CO(2 was similar in monocultures and mixtures. The grass A. odoratum and legume T. repens were most promoted in 6-species mixtures, and together with L. corniculatus, caused the net biomass increase in 6-species mixtures. These plant species also had highest rates of (13C-label translocation, and for A. odoratum and T. repens this effect was greatest in plant individuals grown in species mixtures. Our study reveals that short-term plant C translocation can be accelerated in plant individuals of legume and C3 grass species when grown in mixtures, and that this is strongly positively related to overyielding. These results demonstrate a mechanistic coupling between changes in intraspecific plant carbon physiology and increased

  12. Co-carbonization coal/carbonaceous wastes mixtures

    Czech Academy of Sciences Publication Activity Database

    Kříž, Vlastimil; Brožová, Zuzana

    Ostrava: Vysoká škola báňská, 2005 - (Fečko, P.), s. 41-46 ISBN 80-248-0786-6. [Conference on environment and mineral processing /9./. Ostrava (CZ), 23.06.2005-25.06.2005] Institutional research plan: CEZ:AV0Z30460519 Keywords : coal * co-carbonization * waste s Subject RIV: DM - Solid Waste and Recycling

  13. Sintering uranium oxide in the reaction product of hydrogen-carbon dioxide mixtures

    International Nuclear Information System (INIS)

    Compacted pellets of uranium oxide alone or containing one or more additives such as plutonium dioxide, gadolinium oxide, titanium dioxide, silica, and alumina are heated to 900 to 15990C in the presence of a mixture of hydrogen and carbon dioxide, either alone or with an inert carrier gas and held at the desired temperature in this atmosphere to sinter the pellets. The sintered pellets are then cooled in an atmosphere having an oxygen partial pressure of 10-4 to 10-18 atm of oxygen such as dry hydrogen, wet hydrogen, dry carbon monoxide, wet carbon monoxide, inert gases such as nitrogen, argon, helium, and neon and mixtures of ayny of the foregoing including a mixture of hydrogen and carbon dioxide. The ratio of hydrogen to carbon dioxide in the gas mixture fed to the furnace is controlled to give a ratio of oxygen to uranium atoms in the sintered particles within the range of 1.98:1 to about 2.10:1. The water vapor present in the reaction products in the furnace atmosphere acts as a hydrolysis agent to aid removal of fluoride should such impurity be present in the uranium oxide. (U.S.)

  14. Engineering analysis for disposal of depleted uranium tetrafluoride (UF4)

    International Nuclear Information System (INIS)

    This report presents and evaluates options for disposing of depleted uranium in the chemical form of uranium tetrafluoride (UF4). Two depleted uranium inventories are considered. One results from the original U.S. Department of Energy (DOE) inventory of 560,000 metric tons (te) of depleted uranium hexafluoride (UF6); the other inventory is the original DOE inventory augmented by 145,000 te of depleted UF6 from the United States Enrichment Corporation. Preconceptual designs are included for three disposal options: disposal in a vault, disposal in an engineered trench, and disposal in a deep mine cavity. The disposal container is taken to be either a 30-gallon drum or a 55-gallon drum. Descriptions of the facilities associated with the three disposal options are provided. Staffing estimates for the construction and operation of the facilities are also provided. Wastes and emissions from the facilities during construction, operation, and maintenance have been estimated. Parametric studies have also been performed on the basis of 25% and 50% of the original inventory

  15. Fuels by Waste Plastics Using Activated Carbon, MCM-41, HZSM-5 and Their Mixture

    Directory of Open Access Journals (Sweden)

    Miskolczi Norbert

    2016-01-01

    Full Text Available Waste material was pyrolyzed in a horizontal tubular reactor at 530-540°C using different catalysts, such as activated carbon, MCM-41, HZSM-5 and their mixtures. Products were investigated by gas-chromatography, EDXRFS and standardized methods. Catalysts significantly affected the yields of volatiles; e.g. HZSM-5 catalyst increased especially the yield of gaseous hydrocarbons, while MCM-41 catalyst was responsible for increasing the pyrolysis oil yield. Synergistic effects were found using mixtures of different catalysts. Furthermore the catalysts modified the main carbon frame of the products. Pyrolysis oil obtained over HZSM-5 catalyst contained large amounts of aromatics, while MCM-41 catalyst mainly isomerized the carbon frame. Regarding contaminants it was concluded, that the sulphur content could be significantly decreased by activated carbon, however it had only a slight effect to the other properties of the products.

  16. Interlaminar improvement of carbon fiber/epoxy composites via depositing mixture of carbon nanotubes and sizing agent

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • COOH-CNTs can react with sizing agent, and the optimum reaction ratio was 1:20. • Carbon fibers were dipped into the mixture bath of CNTs and sizing agent. • SEM results indicate that fibers surfaces were coated with CNTs and sizing agent. • ILSS was increased by 67.01% for the composites after the mixture coating process. • Single fibers tensile strength was maintained after the deposited process. - Abstract: The effects of deposition to carbon fibers surfaces with mixture of functionalized multi-walled carbon fibers (MWCNTs) and sizing agent were investigated. Relationships between CNTs and sizing agent were studied with Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectroscopy (XPS) and Ubbelohde viscometer. The results revealed that CNTs could react with sizing agent at 120 °C, and optimal reaction occurs when mass ratio was about 1:20. Then, carbon fibers were immersed in mixed aqueous suspension of CNTs and sizing agent with the above ratio dispersed by ultrasonication. According to scanning electron microscope (SEM) observations, fibers surfaces were coated with CNTs and sizing agent. The static contact angle tests indicated wetting performance between fibers and epoxy resin were improved after deposited procedures. Interlaminar shear strength was increased by 67.01% for fibers/epoxy resin composites after mixture deposited process. Moreover, the tensile strength of single fibers after depositing showed a slightly increase compared with that of fibers without depositing layer

  17. Yields of light products in the radiolysis of isooctane-carbon tetrachloride mixtures

    International Nuclear Information System (INIS)

    The radiolysis of isooctane-carbon tetrachloride mixtures was studied. The yields of light froducts from isooctane (hydrogen, methane, isobutane and isobutene) were determined depending on the electron fraction of carbon tetrachloride. The isooctane parent ion C8H18+ produced by 'indirect' ionization was shown to be unstable and to decompose via a series of competing processes including C-C bond rupture. (author)

  18. Hydrate phase equilibrium of ternary gas mixtures containing carbon dioxide, hydrogen and propane

    International Nuclear Information System (INIS)

    Highlights: ► Hydrate phase equilibrium data for ternary gas mixture containing carbon dioxide, hydrogen and propane is presented. ► Heat of hydrate dissociation for the investigated gas mixture is determined from the Clausius–Clapeyron plot. ► Hydrate structure was determined from the calculated heat of hydrate dissociation. -- Abstract: Hydrate phase equilibrium of the ternary guest mixtures containing carbon dioxide, hydrogen and propane at two different compositions were determined. Addition of mole composition of 2.5% propane to the fuel gas (CO2 (40%)/H2 (60%)) mixture reduces the hydrate formation conditions by 66% at the temperature of 278.4 K. A Clausius–Clapeyron plot for the experimental results was plotted and from the slope, the enthalpy of hydrate dissociation was calculated. The enthalpy of dissociation of the mixed hydrate formed from a ternary gas mixture containing mole composition 38.1% CO2, 59.4% H2 and 2.5% C3H8 was found to be 110 kJ · mol−1 and hence it was concluded that the mixed hydrate formed structure II (sII) hydrates. Whereas for the ternary gas mixture containing mole composition 80.0% CO2, 18.8% H2, and 1.2% C3H8, the enthalpy of dissociation of the mixed hydrate was found to be 78 kJ · mol−1 and hence we believe the mixed hydrate formed structure I (sI) hydrate

  19. Electro-catalytic oxidation of ethanol on platinum-iridium mixtures supported on glassy carbon

    International Nuclear Information System (INIS)

    Electro-catalytic oxidation of ethanol on platinum-iridium mixtures supported on glassy carbon was studied, in acid media at different temperatures and concentrations. During the maturation time of deposited iridium, the surface is covered by an irreversible oxide formation, which affects the behavior of the catalytic mixture. The Pt70 Ir30 and Pt90 Ir10 mixtures seem to be a little more active than the Pt/C electrode at potentials below 800 mV (vs. HRE). In all electrodes appears two reactions: partial ethanol oxidation to produce acetaldehyde (main path of reaction at low temperatures and high electrode coverage with ethanol adsorption residues) and the total oxidation to carbon dioxide which is considerable at potential above 800 mV and it is increased with increasing temperature

  20. Increased plant carbon translocation linked to overyielding in grassland species mixtures

    NARCIS (Netherlands)

    Deyn, de G.B.; Quirk, H.; Oakley, S.; Ostle, N.J.; Bardgett, R.D.

    2012-01-01

    Plant species richness and productivity often show a positive relationship, but the underlying mechanisms are not fully understood, especially at the plant species level. We examined how growing plants in species mixture influences intraspecific rates of short-term carbon (C-) translocation, and det

  1. Carbon/Hydrogen ratio determination in hydrocarbons and its mixtures by electron backscattering technique

    International Nuclear Information System (INIS)

    A method carbon/hydrogen ratio (C/H) determination in hydrocarbons and its mixtures was improved using the electron backscattering technique. Besides the hetero atoms (S,O and N) influence in petroleum is studied for being able to determinate the C/H ratio in cuban petroleum with high sulphur contents

  2. Viscosity prediction of carbon dioxide plus hydrocarbon mixtures using the friction theory

    DEFF Research Database (Denmark)

    Zeberg-Mikkelsen, Claus Kjær; Cisneros, Sergio; Stenby, Erling Halfdan

    2002-01-01

    The general one-parameter f-theory model has been used in conjunction with the SRK and the PR EOS to predict the viscosity of well-defined carbon dioxide + hydrocarbon mixtures. The predicted viscosities are within the uncertainty appropriate for most industrial applications. Although the studied...

  3. Transport of a liquid water and methanol mixture through carbon nanotubes under a chemical potential gradient

    Science.gov (United States)

    Zheng, Jie; Lennon, Erin M.; Tsao, Heng-Kwong; Sheng, Yu-Jane; Jiang, Shaoyi

    2005-06-01

    In this work, we report a dual-control-volume grand canonical molecular dynamics simulation study of the transport of a water and methanol mixture under a fixed concentration gradient through nanotubes of various diameters and surface chemistries. Methanol and water are selected as fluid molecules since water represents a strongly polar molecule while methanol is intermediate between nonpolar and strongly polar molecules. Carboxyl acid (-COOH) groups are anchored onto the inner wall of a carbon nanotube to alter the hydrophobic surface into a hydrophilic one. Results show that the transport of the mixture through hydrophilic tubes is faster than through hydrophobic nanotubes although the diffusion of the mixture is slower inside hydrophilic than hydrophobic pores due to a hydrogen network. Thus, the transport of the liquid mixture through the nanotubes is controlled by the pore entrance effect for which hydrogen bonding plays an important role.

  4. Carbon nanofibers synthesized by pyrolysis of chloroform and ethanol mixture

    International Nuclear Information System (INIS)

    Platelet graphite nanofibers (PGNFs) and turbostratic carbon nanofibers (TSCNFs) were synthesized by the pyrolysis of 3 and 10 vol% chloroform in ethanol, respectively, in the presence of Ni catalyst at 700 °C. Auger electron spectrometry analysis reveals that the participation of chloroform in the synthesis led to Ni–Cl bonding on the surface of the catalysts, resulting in a relatively poor crystalline layer and a coarse surface. Furthermore, the Ni–Cl compound affected the melting point and mobility of Ni, changing the morphology and geometrical shape of Ni particles. A low amount of chlorine in the catalyst led to the formation of smaller catalyst particles with a flat surface, resulting in graphene nanosheets stacked perpendicular to the fiber axis, which became PGNFs. In contrast, a high amount of chlorine in the catalyst led to the aggregation of the catalyst and thus the formation of large catalyst particles with a rough surface, resulting in the random stacking of graphene nanosheets, which became TSCNFs. The participation of chlorine was found to be important in the synthesis of the PGNFs and TSCNFs. - Graphical abstract: Display Omitted - Highlights: • The morphology of CNFs changed while different amount of CHCl3 presented. • The interaction of Ni and Cl changed the geometry and morphology of catalysts. • The structure of CNFs formed attributed to the surface morphology of catalysts. • PGNFs and TSCNFs were perpendicular and random stacking of graphene

  5. Carbonitridation of mechanically activated mixtures of zircon and carbon

    Energy Technology Data Exchange (ETDEWEB)

    Setoudeh, N., E-mail: nsetoudeh@mail.yu.ac.ir [Materials Engineering Department, Yasouj University, Yasouj (Iran, Islamic Republic of); Welham, N.J., E-mail: nicholas.welham@gmail.com [West Australian School of Mines, Curtin University, PO Box U1977, Perth, Western Australia (Australia)

    2014-02-15

    Highlights: • Formation temperature of ZrN and ZrC decreased to 1400 °C in the five hours milled sample. • Either ZrC or ZrN were observed in the heating of 6:1 C:Zircon samples under argon/nitrogen atmospheres. • Amount of tetragonal zirconia increased in nitrogen atmosphere. • Percentage of tetragonal zirconia increased at higher C:Zircon ratios. -- Abstract: Two different stoichiometries of zircon (ZrSiO{sub 4}) and activated carbon (C:zircon molar ratios of 3:1 and 6:1) were milled together at for 5 h and subjected to thermo-gravimetric analysis (TGA). TGA runs were performed under argon and nitrogen atmospheres. The main mass loss reaction started at around 1200 °C in all samples, but the mass loss was greater in the 6:1 C:zircon ratio samples in nitrogen. X-ray diffraction (XRD) of the residues showed the decomposition of zircon was nearly complete. Traces of ZrN along with monoclinic and tetragonal forms of zirconia were observed in the nitrogen atmosphere, however only zirconia was present after heating in argon. Heating the 6:1 C:zircon molar ratio sample for 1 h at 1400 °C in argon resulted in the formation of ZrC and SiC, in nitrogen ZrN was formed.

  6. Carbonitridation of mechanically activated mixtures of zircon and carbon

    International Nuclear Information System (INIS)

    Highlights: • Formation temperature of ZrN and ZrC decreased to 1400 °C in the five hours milled sample. • Either ZrC or ZrN were observed in the heating of 6:1 C:Zircon samples under argon/nitrogen atmospheres. • Amount of tetragonal zirconia increased in nitrogen atmosphere. • Percentage of tetragonal zirconia increased at higher C:Zircon ratios. -- Abstract: Two different stoichiometries of zircon (ZrSiO4) and activated carbon (C:zircon molar ratios of 3:1 and 6:1) were milled together at for 5 h and subjected to thermo-gravimetric analysis (TGA). TGA runs were performed under argon and nitrogen atmospheres. The main mass loss reaction started at around 1200 °C in all samples, but the mass loss was greater in the 6:1 C:zircon ratio samples in nitrogen. X-ray diffraction (XRD) of the residues showed the decomposition of zircon was nearly complete. Traces of ZrN along with monoclinic and tetragonal forms of zirconia were observed in the nitrogen atmosphere, however only zirconia was present after heating in argon. Heating the 6:1 C:zircon molar ratio sample for 1 h at 1400 °C in argon resulted in the formation of ZrC and SiC, in nitrogen ZrN was formed

  7. Carbon nanofibers synthesized by pyrolysis of chloroform and ethanol mixture

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Wang-Hua [Department of Chemical Engineering, National Chung Cheng University, Chia-Yi, 62102, Taiwan (China); Li, Yuan-Yao, E-mail: chmyyl@ccu.edu.tw [Department of Chemical Engineering, National Chung Cheng University, Chia-Yi, 62102, Taiwan (China); Graduate Institute of Opto-Mechatronics, National Chung Cheng University, Chia-Yi, 62102, Taiwan (China); Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, Chia-Yi, 62102, Taiwan (China)

    2015-08-01

    Platelet graphite nanofibers (PGNFs) and turbostratic carbon nanofibers (TSCNFs) were synthesized by the pyrolysis of 3 and 10 vol% chloroform in ethanol, respectively, in the presence of Ni catalyst at 700 °C. Auger electron spectrometry analysis reveals that the participation of chloroform in the synthesis led to Ni–Cl bonding on the surface of the catalysts, resulting in a relatively poor crystalline layer and a coarse surface. Furthermore, the Ni–Cl compound affected the melting point and mobility of Ni, changing the morphology and geometrical shape of Ni particles. A low amount of chlorine in the catalyst led to the formation of smaller catalyst particles with a flat surface, resulting in graphene nanosheets stacked perpendicular to the fiber axis, which became PGNFs. In contrast, a high amount of chlorine in the catalyst led to the aggregation of the catalyst and thus the formation of large catalyst particles with a rough surface, resulting in the random stacking of graphene nanosheets, which became TSCNFs. The participation of chlorine was found to be important in the synthesis of the PGNFs and TSCNFs. - Graphical abstract: Display Omitted - Highlights: • The morphology of CNFs changed while different amount of CHCl{sub 3} presented. • The interaction of Ni and Cl changed the geometry and morphology of catalysts. • The structure of CNFs formed attributed to the surface morphology of catalysts. • PGNFs and TSCNFs were perpendicular and random stacking of graphene.

  8. Reduction of carbon monoxide emissions in burning processes of gaseous fuel mixtures

    International Nuclear Information System (INIS)

    The carbon monoxide produced in the combustion of gaseous fuel mixtures of low hydrocarbon-air content represents a transition component of high risk for living organisms. The limit of admissible concentration of carbon monoxide in the atmosphere is 50 ppm. The paper presents a method of reduction of monoxide carbon present in the combustion emissions which can be can achieved by means of the chemical reaction CO+OH -> H + CO2. The hydroxyl radical can be obtained either by thermic decomposition or by hydrogen injection. (author). 3 figs., 4 refs

  9. Mass spectroscopic study of thermodynamics of molybdenum and tungsten tetrafluorides sublimation

    International Nuclear Information System (INIS)

    By the Knudsen effusion method with mass-spectral analysis of the gas phase composition the sublimation processes of molybdenum and tungsten tetrafluorides are investigated. It is shown that the sublimation of compounds is accompanied by their disproportionation. The saturated vapor above molybdenum tetrafluoride consists of MoFs molecules, above tungsten tetrafluoride - of WF6 molecules. According to the second and third thermodynamics laws calculated are for standard conditions and 298.15 K enthalpies of reactions of disproportionation (152.7+-6.3, 93.7+-12.6 kJ/mol), formation (-1158.5+-26.4, -1210.0+-13.0 kJ/mol), sublimation (204.5+-22.2, 281.2+-16.7 kJ/mol) for MoF4 and WF4, respectively

  10. Thermodynamic promotion of carbon dioxide-clathrate hydrate formation by tetrahydrofuran, cyclopentane and their mixtures

    DEFF Research Database (Denmark)

    Herslund, Peter Jørgensen; Thomsen, Kaj; Abildskov, Jens;

    2013-01-01

    Gas clathrate hydrate dissociation pressures are reported for mixtures of carbon dioxide, water and thermodynamic promoters forming structure II hydrates.Hydrate (H)-aqueous liquid (Lw)-vapour (V) equilibrium pressures for the ternary system composed of water, tetrahydrofuran (THF), and carbon......) equilibrium data are presented for the ternary system of water-cyclopentane-carbon dioxide at temperatures ranging from 285.2K down to 275.5K.New four-phase H-Lw-La-V equilibrium data for the quaternary system water-THF-cyclopentane-carbon dioxide are presented in the temperature range from 275.1K to 286.6K....... It is shown that upon adding THF to the pure aqueous phase to form a 4mass percent solution, the equilibrium pressure of the formed hydrates may be lowered compared to the ternary system of water, cyclopentane and carbon dioxide. © 2013 Elsevier Ltd....

  11. Combined physical and chemical absorption of carbon dioxide in a mixture of ionic liquids

    International Nuclear Information System (INIS)

    Highlights: • Carbon dioxide can be absorbed in mixtures of two ionic liquids: [C2mim][EtSO4] and [C2mim][OAc]. • A combination of physical and chemical absorption mechanisms is observed. • The CO2 absorption capacity of the mixture of ionic liquids decreases with increasing temperature. • [C2mim][EtSO4] in the mixture prevents solidification of the product resulting from reaction of [C2mim][OAc] and CO2. • Density and viscosity studies of the mixture of ionic liquids also lead to synergies, in particular at low temperatures. - Abstract: Ionic liquids have attracted great interest recently as the basis of a potential alternative technology for the capture of carbon dioxide. Beyond the inherent tunability of properties of individual ionic liquids, a further strategy in optimising the ionic liquid sorbent for this application is the use of mixtures of ‘pure’ ionic liquids. Some ionic liquids absorb CO2 physically, whereas others do so chemically. Both mechanisms of absorption present advantages and disadvantages for a CO2 capture process operating in a continuous regime. In this work, a mixture of 1-ethyl-3-methylimidazolium acetate (an ionic liquid that reacts chemically with CO2) and 1-ethyl-3-methylimidazolium ethylsulfate (an ionic liquid that absorbs CO2 only through a physical mechanism) was investigated for the absorption of CO2 as a function of temperature and at pressures up to 17 bar. The absorption/desorption studies were complemented by the characterisation of thermal and physical properties of the mixture of ionic liquids, which provide extra information on the interactions at a molecular level, and are also critical for the assessment of its suitability for a proposed process and for the subsequent process design

  12. Solubility correlation and phase behaviors of carbon dioxide and lubricant oil mixtures

    International Nuclear Information System (INIS)

    Recently, carbon dioxide is being considered as one of the promising environmentally-friendly refrigerants, and extensive studies on the 'trans-critical' vapor-compression cycle using CO2 have been undertaken both experimentally and theoretically. In the vapor compression cycle, lubricant oils are always required, and thus thermophysical properties of lubricant and refrigerant mixtures must be well understood. Currently, the lubricants of choice are polyalkylene glycol (PAG) or polyol ester (POE) oils. Several experimental solubility data for these oils have been published, but those experimental data have not been analyzed yet theoretically (or with thermodynamic equations). In this report, we have investigated the phase behavior (or solubility) of CO2 + PAG and POE mixtures, correlating experimental solubility data with our equation-of-state (EOS) model. Observed data have been successfully correlated with the present EOS, which is used for predicting the general phase behavior for mixtures of CO2 with these lubricant oils

  13. Carbon ion pump for removal of carbon dioxide from combustion gas and other gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.

    2014-08-19

    A novel method and system of separating carbon dioxide from flue gas is introduced. Instead of relying on large temperature or pressure changes to remove carbon dioxide from a solvent used to absorb it from flue gas, the ion pump method, as disclosed herein, dramatically increases the concentration of dissolved carbonate ion in solution. This increases the overlying vapor pressure of carbon dioxide gas, permitting carbon dioxide to be removed from the downstream side of the ion pump as a pure gas. The ion pumping may be obtained from reverse osmosis, electrodialysis, thermal desalination methods, or an ion pump system having an oscillating flow in synchronization with an induced electric field.

  14. Carbon ion pump for removal of carbon dioxide from combustion gas and other gas mixtures

    Science.gov (United States)

    Aines, Roger D.; Bourcier, William L.

    2010-11-09

    A novel method and system of separating carbon dioxide from flue gas is introduced. Instead of relying on large temperature or pressure changes to remove carbon dioxide from a solvent used to absorb it from flue gas, the ion pump method, as disclosed herein, dramatically increases the concentration of dissolved carbonate ion in solution. This increases the overlying vapor pressure of carbon dioxide gas, permitting carbon dioxide to be removed from the downstream side of the ion pump as a pure gas. The ion pumping may be obtained from reverse osmosis, electrodialysis, thermal desalination methods, or an ion pump system having an oscillating flow in synchronization with an induced electric field.

  15. CFD Simulation for Separation of Carbon Dioxide-Methane Mixture by Pressure Swing Adsorption

    OpenAIRE

    K. Rambabu; Muruganandam, L.; Velu, S.

    2014-01-01

    A developing technology for gas separations is pressure swing adsorption, which has been proven to be more economical and energy efficient compared to other separation methods like cryogenic distillation and membrane separation. A pressure swing adsorption (PSA) column, with carbon dioxide-methane as feed mixture and 6-FDA based polyimides as the adsorbent, was modeled and simulated in this work. Ansys Fluent 12.1, along with supplementary user defined functions, was used to develop a 2D tran...

  16. Extending the Row of Lanthanide Tetrafluorides: A Combined Matrix-Isolation and Quantum-Chemical Study.

    Science.gov (United States)

    Vent-Schmidt, Thomas; Fang, Zongtang; Lee, Zachary; Dixon, David; Riedel, Sebastian

    2016-02-01

    Only the neutral tetrafluorides of Ce, Pr, and Tb as well as the [LnF7 ](3-) anions of Dy and Nd, with the metal in the +IV oxidation state, have been previously reported. We report our attempts to extend the row of neutral lanthanide tetrafluorides through the reaction of laser-ablated metal atoms with fluorine and their stabilization and characterization by matrix-isolation IR spectroscopy. In addition to the above three tetrafluorides, we found two new tetrafluorides, (3) NdF4 and (7) DyF4 , both of which are in the +IV oxidation state, which extends this lanthanide oxidation state to two new metals. Our experimental results are supported by quantum-chemical calculations and the role of the lanthanide oxidation state is discussed for both the LnF4 and [LnF4 ](-) species. Most of the LnF4 species are predicted to be in the +IV oxidation state and all of the [LnF4 ](-) anions are predicted to be in the +III oxidation state. The LnF4 species are predicted to be strong oxidizing agents and the LnF3 species are predicted to be moderate to strong Lewis acids. PMID:26786900

  17. Equation of state for partially ionized carbon and oxygen mixtures at high temperatures

    CERN Document Server

    Massacrier, G; Chabrier, G

    2011-01-01

    The equation of state (EOS) for partially ionized carbon, oxygen, and carbon-oxygen mixtures at temperatures 3\\times10^5 K <~ T <~ 3\\times10^6 K is calculated over a wide range of densities, using the method of free energy minimization in the framework of the chemical picture of plasmas. The free energy model is an improved extension of our model previously developed for pure carbon (Phys. Rev. E, 72, 046402; arXiv:physics/0510006). The internal partition functions of bound species are calculated by a self-consistent treatment of each ionization stage in the plasma environment taking into account pressure ionization. The long-range Coulomb interactions between ions and screening of the ions by free electrons are included using our previously published analytical model, recently improved, in particular for the case of mixtures. We also propose a simple but accurate method of calculation of the EOS of partially ionized binary mixtures based on detailed ionization balance calculations for pure substances.

  18. Ultrasonic deagglomeration of aluminum nanopowders with multi-walled carbon nanotube mixtures

    Science.gov (United States)

    Kozulin, Alexander A.; Vorozhtsov, Sergey A.; Kulkov, Sergey S.; Teipel, U.; Kulkov, Sergey N.

    2015-10-01

    Comprehensive investigations of aluminum nanopowders, multi-walled carbon nanotubes, and aluminum mixtures with multi-walled carbon nanotubes subjected to ultrasonic deagglomeration in a liquid medium were performed, using microstructural, X-ray diffraction, thermogravimetric, and calorimetric analyses, and specific surface area measurements. The regime of ultrasonic deagglomeration of aluminum nanopowders with multi-walled carbon nanotubes in a liquid medium is described, during which the division of large agglomerates and creation of homogeneous distribution of mixtures components in the volume takes place. It was determined that ultrasonic treatment influences the morphology and crystalline structure of investigated mixtures, contributes to the appearance of X-ray amorphous phase, decreases the specific surface area of the aluminum nanopowder from 13 to 12 m2/g, and increases the pore volume and average size from 0.04 to 0.06 cm3/g and from 12 to 19 nm, respectively. The size of coherently-diffracting domain was determined by the X-ray diffraction analysis is close to that estimated from the specific surface area and corresponds to average crystallites size in the materials under study.

  19. Ultrasonic deagglomeration of aluminum nanopowders with multi-walled carbon nanotube mixtures

    International Nuclear Information System (INIS)

    Comprehensive investigations of aluminum nanopowders, multi-walled carbon nanotubes, and aluminum mixtures with multi-walled carbon nanotubes subjected to ultrasonic deagglomeration in a liquid medium were performed, using microstructural, X-ray diffraction, thermogravimetric, and calorimetric analyses, and specific surface area measurements. The regime of ultrasonic deagglomeration of aluminum nanopowders with multi-walled carbon nanotubes in a liquid medium is described, during which the division of large agglomerates and creation of homogeneous distribution of mixtures components in the volume takes place. It was determined that ultrasonic treatment influences the morphology and crystalline structure of investigated mixtures, contributes to the appearance of X-ray amorphous phase, decreases the specific surface area of the aluminum nanopowder from 13 to 12 m2/g, and increases the pore volume and average size from 0.04 to 0.06 cm3/g and from 12 to 19 nm, respectively. The size of coherently-diffracting domain was determined by the X-ray diffraction analysis is close to that estimated from the specific surface area and corresponds to average crystallites size in the materials under study

  20. Ultrasonic deagglomeration of aluminum nanopowders with multi-walled carbon nanotube mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Kozulin, Alexander A., E-mail: kozulyn@ftf.tsu.ru; Vorozhtsov, Sergey A., E-mail: vorn1985@gmail.com; Kulkov, Sergey S.; Kulkov, Sergey N. [National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Teipel, U. [Georg Simon Ohm University of Applied Sciences, Nuremberg (Germany)

    2015-10-27

    Comprehensive investigations of aluminum nanopowders, multi-walled carbon nanotubes, and aluminum mixtures with multi-walled carbon nanotubes subjected to ultrasonic deagglomeration in a liquid medium were performed, using microstructural, X-ray diffraction, thermogravimetric, and calorimetric analyses, and specific surface area measurements. The regime of ultrasonic deagglomeration of aluminum nanopowders with multi-walled carbon nanotubes in a liquid medium is described, during which the division of large agglomerates and creation of homogeneous distribution of mixtures components in the volume takes place. It was determined that ultrasonic treatment influences the morphology and crystalline structure of investigated mixtures, contributes to the appearance of X-ray amorphous phase, decreases the specific surface area of the aluminum nanopowder from 13 to 12 m{sup 2}/g, and increases the pore volume and average size from 0.04 to 0.06 cm{sup 3}/g and from 12 to 19 nm, respectively. The size of coherently-diffracting domain was determined by the X-ray diffraction analysis is close to that estimated from the specific surface area and corresponds to average crystallites size in the materials under study.

  1. Adsorption and desorption of mixtures of organic vapors on beaded activated carbon.

    Science.gov (United States)

    Wang, Haiyan; Jahandar Lashaki, Masoud; Fayaz, Mohammadreza; Hashisho, Zaher; Philips, John H; Anderson, James E; Nichols, Mark

    2012-08-01

    In this study, adsorption and desorption of mixtures of organic compounds commonly emitted from automotive painting operations were experimentally studied. A mixture of two alkanes and a mixture of eight organic compounds were adsorbed onto beaded activated carbon (BAC) and then thermally desorbed under nitrogen. Following both adsorption and regeneration, samples of the BAC were chemically extracted. Gas chromatography-mass spectrometry (GC-MS) was used to quantify the compounds in the adsorption and desorption gas streams and in the BAC extracts. In general, for both adsorbate mixtures, competitive adsorption resulted in displacing low boiling point compounds by high boiling point compounds during adsorption. In addition to boiling point, adsorbate structure and functionality affected adsorption dynamics. High boiling point compounds such as n-decane and 2,2-dimethylpropylbenzene were not completely desorbed after three hours regeneration at 288 °C indicating that these two compounds contributed to heel accumulation on the BAC. Additional compounds not present in the mixtures were detected in the extract of regenerated BAC possibly due to decomposition or other reactions during regeneration. Closure analysis based on breakthrough curves, solvent extraction of BAC and mass balance on the reactor provided consistent results of the amount of adsorbates on the BAC after adsorption and/or regeneration. PMID:22742925

  2. Measurements of mixtures with carbon dioxide under supercritical conditions using commercial high pressure equipment

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Luciana L.P.R. de; Rutledge, Luis Augusto Medeiros; Moreno, Eesteban L.; Hovell, Ian; Rajagopal, Krishnaswamy [Universidade Federal do Rio de Janeiro (LATCA-EQ-UFRJ), RJ (Brazil). Escola de Quimica. Lab. de Termodinamica e Cinetica Aplicada

    2012-07-01

    There is a growing interest in studying physical properties of binary and multicomponent fluid mixtures with supercritical carbon dioxide (CO{sub 2}) over an extended range of temperature and pressure. The estimation of properties such as density, viscosity, saturation pressure, compressibility, solubility and surface tension of mixtures is important in design, operation and control as well as optimization of chemical processes especially in extractions, separations, catalytic and enzymatic reactions. The phase behaviour of binary and multicomponent mixtures with supercritical CO{sub 2} is also important in the production and refining of petroleum where mixtures of paraffin, naphthene and aromatics with supercritical fluids are often encountered. Petroleum fluids can present a complex phase behaviour in the presence of CO{sub 2}, where two-phase (VLE and LLE) and three phase regions (VLLE) might occur within ranges of supercritical conditions of temperature and pressure. The objective of this study is to develop an experimental methodology for measuring the phase behaviour of mixtures containing CO{sub 2} in supercritical regions, using commercial high-pressure equipment. (author)

  3. Synthesis, mechanical and biological characterization of ionic doped carbonated hydroxyapatite/β-tricalcium phosphate mixtures.

    Science.gov (United States)

    Kannan, S; Vieira, S I; Olhero, S M; Torres, P M C; Pina, S; da Cruz e Silva, O A B; Ferreira, J M F

    2011-04-01

    The influence of ionic substituents in calcium phosphates intended for bone and tooth replacement biomedical applications is an important research topic, owing to the essential roles played by trace elements in biological processes. The present study investigates the mechanical and biological evaluation of ionic doped hydroxyapatite/β-tricalcium phosphate mixtures which have been prepared by a simple aqueous precipitation method. Heat treating the resultant calcium phosphates in a carbonated atmosphere led to the formation of ionic doped carbonated hydroxyapatite/β-tricalcium phosphate mixtures containing the essential ions of biological apatite. The structural analysis determined by Rietveld refinement confirmed the presence of hydroxyapatite as the main phase, together with a considerable amount of β-tricalcium phosphate. Such phase assemblage is essentially due to the influence of substituted ions during synthesis. The results from mechanical tests proved that carbonate substitutions are detrimental for the mechanical properties of apatite-based ceramics. In vitro proliferation assays of osteoblastic-like cells (MC3T3-E1 cell line) to powders revealed that carbonate incorporation can either delay or accelerate MC3T3 proliferation, although reaching the same proliferation levels as control cells after 2 weeks in culture. Further, the powders enable pre-osteoblastic differentiation in a similar manner to control cells, as indirectly measured by ALP activity and Type-I collagen medium secretion. PMID:21146640

  4. Homogeneous water nucleation and droplet growth in methane and carbon dioxide mixtures at 235 K and 10 bar.

    Science.gov (United States)

    Holten, V; van Dongen, M E H

    2010-05-28

    Homogeneous nucleation rates and droplet growth rates of water in pure methane and mixtures of methane and carbon dioxide were measured in an expansion wave tube at 235 K and 10 bar. The nucleation rate in pure methane is three orders of magnitude higher than literature nucleation rates of water in low-pressure helium or argon. Addition of carbon dioxide to the carrier gas mixture increases the rates even more. Specifically, rates in a mixture of methane and 3% carbon dioxide are a factor of 10 higher than the rates in pure methane. With 25% carbon dioxide, the rates are four orders of magnitude higher than the rates in pure methane. An application of the nucleation theorem shows that the critical cluster consists of 22 water molecules and 5 methane molecules, for nucleation in pure methane. Growth rates of water droplets were measured in methane and in methane-carbon dioxide mixtures at 243 K and 11.5 bar. At equal temperature, pressure and water vapor fraction, the growth rate of the squared droplet radius is about 20% lower in the mixture with 25% carbon dioxide than in pure methane. The lower growth rate is caused by a smaller diffusion coefficient of water in the mixture with carbon dioxide; the difference of the diffusion coefficients is qualitatively reproduced by the empirical Fuller correlation combined with Blanc's law. PMID:20515097

  5. Electrical Conductivity of Carbon Pellets from Mixtures of Pyropolymer from Oil Palm Bunch and Cotton Cellulose

    Science.gov (United States)

    Deraman, Mohamad; Zakaria, Sarani; Omar, Ramli; Aziz, Astimar A.

    2000-12-01

    Self-adhesive carbon grains (sacg1) and heat-treated kraft lignin (htkl) were prepared from the oil palm empty fruit bunch, a potential precursor for carbon products due to its large availability from palm oil mills, and sacg was prepared from cellulose (sacg2). Pellets were prepared from mixtures of sacg1 and htkl, as well as sacg1 and sacg2, with varying percentages of htkl (Phtkl%) and sacg2 (Psacg2%). After carbonization up to 1000°C, the measured electrical conductivities, σ (Ω{\\cdot}cm)-1, of the respective pellets follow the equations σ=4.13Phtkl+2.43 and σ=0.53Psacg2+2.55, respectively, indicating that htkl has improved in its conducting phase compared to sacg2.

  6. Sorption of cesium, strontium, iodine, nickel and carbon in mixtures of concrete, crushed rock and bitumen

    International Nuclear Information System (INIS)

    Sorption of Cs-134, Sr-85, I-125, Ni-63 and C-14 on simulated mixtures of materials present in the repositories for low and medium level wastes were studied. Samples were selected according to the Finnish plans for the repositories. The components of the mixtures were crushed rock, concrete (IVO and TVO) and bitumen (TVO) to be used as waste package, backfill and construction material. The ground water used was collected from the planned disposal sites for the low and medium level wastes. The solution-to-solid mass-ratios (V/M) have been chosen to simulate the conditions prevailing in repositories. The Ksub(d)-values of the mixtures were determined by the batch method. The Ksub(d)-values of the mixtures were also calculated using the relative mass of each component and the Ksub(d)-values determined for each component separately. The effect of concrete water as well as the correction due to the ratio of the liquid volume to solid mass (V/M-ratio) was taken into account in the determinations of the calculated Ksub(d)-values. The experimental Ksub(d)-values of cesium were 10 - 115 and 1 - 3 ml/g for TVO's and IVO's mixtures, respectively. The calculated Ksub(d)-values were 2 - 26 times higher than the experimental Ksub(d)-values. The experimental and calculated Ksub(d)-values of strontium, iodine and nickel were the same order of magnitude. The Ksub(d)-values of strontium were about 1 - 16 ml/g. Low sorption of iodine in all samples was found, the Ksub(d)-values were < 0.6 ml/g. The Ksub(d)-values of nickel were 2 - 15 ml/g. The experimental Ksub(d)-values of carbon were 0.1 - 12 ml/g. The calculated Ksub(d)-values of carbon were lower than the experimental Ksub(d)-values. The effect of V/M on Ksub(d) of sample mixtures was low for Sr. For cesium and iodine the Ksub(d) was lower by a factor of 5 for the V/M ratio 0.28:1 than 10:1. For nickel and carbon the Ksub(d)-values were 1 - 3 orders of magnitude smaller for low V/M ratio (0.28:1). (author)

  7. Excess Molar Volumes and Viscosities of Binary Mixture of Diethyl Carbonate+Ethanol at Different Temperatures

    Institute of Scientific and Technical Information of China (English)

    MA Peisheng; LI Nannan

    2005-01-01

    The purpose of this work was to report excess molar volumes and dynamic viscosities of the binary mixture of diethyl carbonate (DEC)+ethanol. Densities and viscosities of the binary mixture of DEC+ethanol at temperatures 293.15 K-343.15 K and atmospheric pressure were determined over the entire composition range. Densities of the binary mixture of DEC+ethanol were measured by using a vibrating U-shaped sample tube densimeter. Viscosities were determined by using Ubbelohde suspended-level viscometer. Densities are accurate to 1.0×10-5 g·cm-3, and viscosities are reproducible within ±0.003 mPa·s. From these data, excess molar volumes and deviations in viscosity were calculated. Positive excess molar volumes and negative deviations in viscosity for DEC+ethanol system are due to the strong specific interactions.All excess molar vo-lumes and deviations in viscosity fit to the Redlich-Kister polynomial equation.The fitting parameters were presented,and the average deviations and standard deviations were also calculated.The errors of correlation are very small.It proves that it is valuable for estimating densities and viscosities of the binary mixture by the correlated equation.

  8. Experimental study of negative corona discharge in pure carbon dioxide and its mixtures with oxygen

    International Nuclear Information System (INIS)

    The products of a negative corona discharge in both pure CO2 and mixtures of CO2 + O2 have been studied using a coaxial cylindrical electrode geometry with particular emphasis on the production of ozone. The discharge current in pure CO2 was found to be highly sensitive to the presence of trace concentrations of molecular oxygen and to changes in the flow speed through the discharge. The effect of dissociative electron attachment to ozone on the discharge current was studied by measurements of ozone and CO production. The ozone concentration increases monotonically with increasing content of oxygen in the mixture with carbon dioxide, whereas the CO concentration exhibits a flat maximum for oxygen concentrations of around 4%. A simple kinetic model of the dominant chemical processes is described and compared with the experimental results

  9. Solubility of Paclitaxel in Mixtures of Dichloromethane and Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    LUO Nin; LU Yingmei; JIANG Yanbin

    2011-01-01

    Phase behavior of paclitaxel in solvent mixtures of dichloromethane and supercritical carbon dioxide was investigated using a supercritical phase monitor.Cloud point pressures were determined as a function of temperature,pressure and paclitaxel content from 313.1 to 343.1K and pressures up to 33.52 MPa.The ternary mixtures exhibit a typical lower critical solution temperature behavior.When paclitaxel content increases,the single-phase region shrinks in size.Three cubic equations of state(Redlich-Kworng,Soave-Redlich-Kwong and Peng-Robinson equation of state) coupled with the van der Waals one-fluid mixing rules were selected to correlate the experimental data.The results indicate that SRK EOS coupled with two binary interaction parameters kij and lij can predict paclitaxel solubility for the best fit of experimental data.

  10. Experimental study of negative corona discharge in pure carbon dioxide and its mixtures with oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Mikoviny, T [Department of Plasma Physics, Comenius University, Mlynska dolina F-2, 84248 Bratislava (Slovakia); Kocan, M [Department of Plasma Physics, Comenius University, Mlynska dolina F-2, 84248 Bratislava (Slovakia); Matejcik, S [Department of Plasma Physics, Comenius University, Mlynska dolina F-2, 84248 Bratislava (Slovakia); Mason, N J [Department of Physics and Astronomy, Centre of Molecular and Optical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Skalny, J D [Department of Plasma Physics, Comenius University, Mlynska dolina F-2, 84248 Bratislava (Slovakia)

    2004-01-07

    The products of a negative corona discharge in both pure CO{sub 2} and mixtures of CO{sub 2} + O{sub 2} have been studied using a coaxial cylindrical electrode geometry with particular emphasis on the production of ozone. The discharge current in pure CO{sub 2} was found to be highly sensitive to the presence of trace concentrations of molecular oxygen and to changes in the flow speed through the discharge. The effect of dissociative electron attachment to ozone on the discharge current was studied by measurements of ozone and CO production. The ozone concentration increases monotonically with increasing content of oxygen in the mixture with carbon dioxide, whereas the CO concentration exhibits a flat maximum for oxygen concentrations of around 4%. A simple kinetic model of the dominant chemical processes is described and compared with the experimental results.

  11. Integrated Data Collection Analysis (IDCA) Program - KClO4/Carbon Mixture

    Energy Technology Data Exchange (ETDEWEB)

    Sandstrom, Mary M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Brown, Geoffrey W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Daniel N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pollard, Colin J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Warner, Kirstin F. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Sorensen, Daniel N. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Remmers, Daniel L. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States). Indian Head Division; Shelley, Timothy J. [Air Force Research Lab. (AFRL), Tyndall AFB, FL (United States); Reyes, Jose A. [Applied Research Associates, Tyndall AFB, FL (United States); Hsu, Peter C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reynolds, John G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-01-31

    The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small- Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of a mixture of KClO4 and activated carbon—KClO4/C mixture. This material was selected because of the challenge of performing SSST testing of a mixture of two solids. The mixture was found to be insensitive to impact, friction, and thermal stimulus, and somewhat sensitive to spark discharge. This effort, funded by the Department of Homeland Security (DHS), ultimately will put the issues of safe handling of these materials in perspective with standard military explosives. The study is adding SSST testing results for a broad suite of different HMEs to the literature. Ultimately the study has the potential to suggest new guidelines and methods and possibly establish the SSST testing accuracies needed to develop safe handling practices for HMEs. Each participating testing laboratory uses identical test materials and preparation methods wherever possible. Note, however, the test procedures differ among the laboratories. The results are compared among the laboratories and then compared to historical data from various sources. The testing performers involved for the KClO4/carbon mixture are Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Indian Head Division, Naval Surface Warfare Center, (NSWC IHD), and Air Force Research Laboratory (AFRL/RXQL). These tests are conducted as a proficiency study in order to establish some consistency in test protocols, procedures, and experiments and to understand how to compare results when these testing variables cannot be made consistent.

  12. Application of the spin trapping technique to the study of radiation effects on gaseous mixtures of carbon monoxide and hydrogen

    International Nuclear Information System (INIS)

    The spin trapping technique has been applied to the radiation chemistry of gaseous mixtures of carbon monoxide and hydrogen. A mixture of CO and H2 has been irradiated with electron beams in the absence or presence of phenyl-N-tert-butylnitrone used as a trapping agent of radicals. Similar experiments have been carried out on hydrogen, helium, and a mixture of CO and deuterium. ESR spectra of the products provide evidence for the formation of H atom and methyl radical from a mixture of CO and H2

  13. Influence of carbon monoxide additives on detonating ability of air-hydrogen mixtures

    International Nuclear Information System (INIS)

    Corrective evaluation of detonating ability of postaccident hydrogen-containing atmosphere of the reactor containment is needed for studies on consequences of sere-re hypothetic accidents at NPPs. Numerical study on effect of CO additives on the size of the detonating cell is carried out. The calculations were conducted within the frames of one-dimensional model with an account of the detailed kinetic combustion scheme (56 elementary chemical reactions). It is established that the CO additives may essentially increase detonating ability of fuel-poor hydrogen + air + carbon monoxide mixtures

  14. Killing wild geese with carbon dioxide or a mixture of carbon dioxide and argon

    NARCIS (Netherlands)

    Gerritzen, M.A.; Reimert, H.G.M.; Lourens, A.; Bracke, M.B.M.; Verhoeven, M.T.W.

    2013-01-01

    The killing of animals is the subject of societal and political debate. Wild geese are caught and killed on a regular basis for fauna conservation and damage control. Killing geese with carbon dioxide (CO2) is commonly practiced, but not listed in legislation on the protection of flora and fauna, an

  15. Measurement of uniform flame movement in carbon monoxide - air mixtures containing either added D2O or H2O

    Science.gov (United States)

    Mcdonald, Glen E

    1950-01-01

    Relative velocities of the flame in a carbon monoxide - air mixture containing either added heavy water or light water were measured in a glass tube. Throughout the range of carbon monoxide - air composition, the flame containing added light water had a faster speed than the flame containing heavy water.

  16. Organic carbon aerogels from the sol-gel polymerization of phenolic-furfural mixtures

    Science.gov (United States)

    Pekala, Richard W.

    1998-04-28

    The sol-gel polymerization of a phenolic-furfural mixture in dilute solution leads to a highly cross-linked network that can be supercritically dried to form a high surface area foam. These porous materials have cell/pore sizes .ltoreq.1000 .ANG., and although they are dark brown in color, they can be classified as a new type of aerogel. The phenolic-furfural aerogel can be pyrolyzed in an inert atmosphere at 1050.degree. C. to produce carbon aerogels. This new aerogel may be used for thermal insulation, chromatographic packing, water filtration, ion-exchange, and carbon electrodes for energy storage devices, such as batteries and double-layer capacitors.

  17. The Effect of Water Vapor on Flame Velocity in Equivalent Carbon Monoxide and Oxygen Mixtures

    Science.gov (United States)

    Fiock, Ernest F; King, H Kendall

    1936-01-01

    This report presents the results of an investigation to study the effect of water vapor upon the spatial speed of flame in equivalent mixtures of carbon monoxide and oxygen at various total pressures from 100 to 780 mm.hg. These results show that, within this pressure range, an increase in flame speed is produced by increasing the mole fraction of water vapor at least as far as saturation at 25 degrees c., and that the rate of this increase is greater the higher the pressure. It is evident that water vapor plays an important part in the explosive oxidation of carbon monoxide; the need for further experimental evidence as to the nature of its action is indicated.

  18. Preparation and characterization of very pure zirconium tetrafluoride. Application to fluorinated glass

    International Nuclear Information System (INIS)

    The synthesis of anhydrous and very pure zirconium tetrafluoride from zirconium tetraborohydride is studied. Zr F4 is used for fabrication of fluorozirconate glass. Zr (BH4)4 is purified by sublimation. Two fluorinating agents F2 and anhydrous HF are used for fluorination. The apparatus is made of fluorinated polymers and a Kel-F prototype reactor was realized. 20 g of Zr F4 are obtained in 44 hrs with a yield of 88 %. Purity is characterized by chemical analysis (atomique absorption spectroscopy and spark mass spectroscopy) and absorption of an optical fiber made of zirconium tetrafluoride. Cr, Ni, Co and Cu content is lower than 0.1 ppm. Possibility of pilot scale production is discussed

  19. Thermal decomposition of ammonium uranous fluoride to anhydrous uranium tetrafluoride in freon - 12 atmosphere

    International Nuclear Information System (INIS)

    A systematic study on the thermal decomposition of the double salt has been carried out. A range of temperature, duration, thickness of layers during heating and flow rate of gas were investigated and the physico-chemical properties of the resulting uranium tetrafluoride determined. The chemical analysis included the determination of U4, UO2 formed, UF4 assay and UO2F2 formed. The X-ray analysis confirmed the formation of anhydrous uranium tetrafluoride after heating of 0.3-cm thick ammonium uranous fluoride layer at 3500C while passing 0.05 litre min-1 Freon-12 for four hours. Emission spectrographic analysis confirmed nuclear purity of the final product

  20. Technology of uranium tetrafluoride preparation by hydrofluorination of UO2 obtained from ammonium diuranate

    International Nuclear Information System (INIS)

    A study of preparation of uranium tetrafluoride by hydrofluorination of UO2 using anhydrous HF is described. Uranium dioxide was obtained by thermal decomposition of amonium diuranate to UO3 and its reduction with hydrogen generated by cracking ammonia gas. The main purpose is to acquire experience for the UF4 preparation and its technology and found out the best operation conditions, envisaging the installation of an experimental semi-pilot unit for training and small production

  1. Phase transition and chemical decomposition of liquid carbon dioxide and nitrogen mixture under extreme conditions

    Science.gov (United States)

    Xiao-Xu, Jiang; Guan-Yu, Chen; Yu-Tong, Li; Xin-Lu, Cheng; Cui-Ming, Tang

    2016-02-01

    Thermodynamic and chemical properties of liquid carbon dioxide and nitrogen (CO2-N2) mixture under the conditions of extremely high densities and temperatures are studied by using quantum molecular dynamic (QMD) simulations based on density functional theory including dispersion corrections (DFT-D). We present equilibrium properties of liquid mixture for 112 separate density and temperature points, by selecting densities ranging from ρ = 1.80 g/cm3 to 3.40 g/cm3 and temperatures from T = 500 K to 8000 K. In the range of our study, the liquid CO2-N2 mixture undergoes a continuous transition from molecular to atomic fluid state and liquid polymerization inferred from pair correlation functions (PCFs) and the distribution of various molecular components. The insulator-metal transition is demonstrated by means of the electronic density of states (DOS). Project supported by the National Natural Science Foundation of China (Grant Nos. 11374217, 11135012, and 11375262) and the Joint Fund of the National Natural Science Foundation of China and the China Academy of Engineering Physics (Grant No. 11176020).

  2. Mutual diffusion of binary liquid mixtures containing methanol, ethanol, acetone, benzene, cyclohexane, toluene, and carbon tetrachloride

    Science.gov (United States)

    Guevara-Carrion, Gabriela; Janzen, Tatjana; Muñoz-Muñoz, Y. Mauricio; Vrabec, Jadran

    2016-03-01

    Mutual diffusion coefficients of all 20 binary liquid mixtures that can be formed out of methanol, ethanol, acetone, benzene, cyclohexane, toluene, and carbon tetrachloride without a miscibility gap are studied at ambient conditions of temperature and pressure in the entire composition range. The considered mixtures show a varying mixing behavior from almost ideal to strongly non-ideal. Predictive molecular dynamics simulations employing the Green-Kubo formalism are carried out. Radial distribution functions are analyzed to gain an understanding of the liquid structure influencing the diffusion processes. It is shown that cluster formation in mixtures containing one alcoholic component has a significant impact on the diffusion process. The estimation of the thermodynamic factor from experimental vapor-liquid equilibrium data is investigated, considering three excess Gibbs energy models, i.e., Wilson, NRTL, and UNIQUAC. It is found that the Wilson model yields the thermodynamic factor that best suits the simulation results for the prediction of the Fick diffusion coefficient. Four semi-empirical methods for the prediction of the self-diffusion coefficients and nine predictive equations for the Fick diffusion coefficient are assessed and it is found that methods based on local composition models are more reliable. Finally, the shear viscosity and thermal conductivity are predicted and in most cases favorably compared with experimental literature values.

  3. Carbon nanostructures and graphite-coated metal nanostructures obtained by pyrolysis of ruthenocene and ruthenocene–ferrocene mixtures

    Indian Academy of Sciences (India)

    L S Panchakarla; A Govindaraj

    2007-02-01

    Pyrolysis of ruthenocene carried out in an atmosphere of argon or hydrogen is found to give rise to spherical nanoparticles of carbon with diameters in the 10–200 nm range. Pyrolysis of ruthenocene as well as mixtures of ruthenocene and ethylene in hydrogen gives rise to spherical nanoparticles, which contain a high proportion of 3 carbon. Under certain conditions, pyrolysis of ruthenocene gives rise to graphite coated ruthenium nanoparticles as well as worm-like carbon structures. Pyrolysis of mixtures of ruthenocene and ferrocene gives rise to nanoparticles or nanorods of FeRu alloys, the composition depending upon the composition of the original mixture. Nanorods of the Ru and FeRu alloys encapsulated in the carbon nanotubes are also formed in the pyrolysis reaction.

  4. Role of titanium tetrafluoride (TiF 4 in conservative dentistry: A systematic review

    Directory of Open Access Journals (Sweden)

    Pragya Wahengbam

    2011-01-01

    Full Text Available The role of fluoride to reduce demineralization and enhance remineralization of dental hard tissue has been well documented. Different forms of fluoride solutions have been topically used in dentistry as prophylactic agents against tooth decay. In the recent past, metal fluorides, especially titanium tetrafluoride, have become popular in the fraternity of dental research due to their unique interaction with dental hard tissue. Many studies on titanium tetrafluoride, with positive and negative conclusions, have been published in many research journals. This gives the reader a plethora of inconclusive results with one study neutralizing the outcome of other, which confuses us regarding the present status of titanium tetrafluoride in the field of dentistry. This is an endeavor to organize and present the various studies of this unique compound, to provide us with a lucid overall review of its versatile potential application in dentistry, along with its fallacy/drawbacks. We have discussed its role as a cariostatic agent, pit and fissure sealant, tooth desensitizer, against dental erosion, as a root canal irrigant and others.

  5. Cooling capacity of water-gas mixtures. Application to the quenching of carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Moreaux, F. [CNRS, Nancy (France); Forgeoux, D. [SAM, Neuves Maisons (France); Jallon, M. [UNIMETAL, Amneville (France)

    1996-12-31

    During the heat treatment of metallic alloys, sometimes it is useful to cool down moderately in temperature range 1000{degrees}C - 600{degrees}C. During the quench in a vaporizable liquid (e.g water), this kind of cooling can be obtain thanks to the film boiling regime. If, in the case of water at 100 {degrees}C the film boiling is stable, the authors have shown the instability of film boiling when the water is at a lower temperature. A means to stabilize the film boiling consists of injecting gas in water. The authors built an experimental apparatus like a bubbles column. The gas is injected at the bottom of the column through a sintered glass. Thanks to a silver probe, the cooling capacity of different gas-water mixtures is measured versus the bubbles size, gas (air, carbon dioxide, hydrogen-nitrogen mixture) and water temperature. A great range of reproducible coolings is obtained versus these various parameters. This process is tested for the treatment of the carbon steels. In the special case of the 1080 steel, the authors have determined the mechanical characteristics for samples of 6 and 16 mm in diameter quenched in this quenching medium. For the samples of 6 mm in diameter, the values obtained are equivalent to these of lead-patented wire.

  6. CFD Simulation for Separation of Carbon Dioxide-Methane Mixture by Pressure Swing Adsorption

    Directory of Open Access Journals (Sweden)

    K. Rambabu

    2014-01-01

    Full Text Available A developing technology for gas separations is pressure swing adsorption, which has been proven to be more economical and energy efficient compared to other separation methods like cryogenic distillation and membrane separation. A pressure swing adsorption (PSA column, with carbon dioxide-methane as feed mixture and 6-FDA based polyimides as the adsorbent, was modeled and simulated in this work. Ansys Fluent 12.1, along with supplementary user defined functions, was used to develop a 2D transient Eulerian laminar viscous flow model for the PSA column. The model was validated by comparing the simulated results with established analytical models for PSA. The developed numerical model was used to determine the carbon dioxide concentration in the column as a function of time based on different operating conditions. Effect of various operating parameters like pressure, temperature, and flow rate on the separation efficiency has been studied and reported. Optimization studies were carried out to obtain suitable operating conditions for the feed gases separation. Simulation studies were carried out to determine the separation length required for complete separation of the feed mixture corresponding to different inlet feed concentrations which were entering the column at a given flow rate.

  7. Anodic polarization behavior of pure copper in carbonate solutions and in bentonite/sand mixture

    International Nuclear Information System (INIS)

    Copper is one of the candidate materials for overpacks. Anodic polarization curves of pure copper were measured at 80degC in carbonate solution and in bentonite/sand mixture in order to understand the corrosion behavior of copper overpack at oxidizing period. The experimental results in carbonate solutions indicated that the anodic polarization curves became active dissolution type with increase in chloride ion concentration, while anodic polarization curves became passive type with increase in bicarbonate ion concentration. No effect of sulfate ion concentration was observed on the type of anodic polarization curve. The passive film break down potential became less noble with increase in chloride ion concentration and sulfate ion concentration. In contrast, the passive film break down potential became noble with increase in bicarbonate ion concentration. By the comparison of these experimental results with previous study performed at 30degC, it was indicated that anodic polarization curves become passive type with the rise of temperature. However, no effect of temperature on passive film break down potential was observed thin the experimental conditions. As to the results in bentonite/sand mixture, the effects of the composition in test solutions on the anodic polarization curves were small and the anodic polarization curves were almost active dissolution types. (author)

  8. The production of carbon nanofibers and thin films on palladium catalysts from ethylene oxygen mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Jonathan [Los Alamos National Laboratory; Doorn, Stephen [Los Alamos National Laboratory; Atwater, Mark [UNM MECH.ENG.; Leseman, Zayd [UNM MECH.ENG.; Luhrs, Claudia C [UNM ENG.MECH; Diez, Yolanda F [SPAIN; Diaz, Angel M [SPAIN

    2009-01-01

    The characteristics of carbonaceous materials deposited in fuel rich ethylene-oxygen mixtures on three types of palladium: foil, sputtered film, and nanopowder, are reported. It was found that the form of palladium has a dramatic influence on the morphology of the deposited carbon. In particular, on sputtered film and powder, tight 'weaves' of sub-micron filaments formed quickly. In contrast, on foils under identical conditions, the dominant morphology is carbon thin films with basal planes oriented parallel to the substrate surface. Temperature, gas flow rate, reactant flow ratio (C2H4:02), and residence time (position) were found to influence both growth rate and type for all three forms of Pd. X-ray diffraction, high-resolution transmission electron microscopy, temperature-programmed oxidation, and Raman spectroscopy were used to assess the crystallinity of the as-deposited carbon, and it was determined that transmission electron microscopy and x-ray diffraction were the most reliable methods for determining crystallinity. The dependence of growth on reactor position, and the fact that no growth was observed in the absence of oxygen support the postulate that the carbon deposition proceeds by combustion generated radical species.

  9. Carbon nanostructures and graphite-coated metal nanostructures obtained by pyrolysis of ruthenocene and ruthenocene–ferrocene mixtures

    OpenAIRE

    Panchakarla, LS; Govindaraj, A.

    2007-01-01

    Pyrolysis of ruthenocene carried out in an atmosphere of argon or hydrogen is found to give rise to spherical nanoparticles of carbon with diameters in the 10–200 nm range. Pyrolysis of ruthenocene as well as mixtures of ruthenocene and ethylene in hydrogen gives rise to spherical nanoparticles, which contain a high proportion of sp3 carbon. Under certain conditions, pyrolysis of ruthenocene gives rise to graphite coated ruthenium nanoparticles as well as worm-like carbon structures. Pyrolys...

  10. Molecular Dynamics Simulations of Carbon Dioxide, Methane, and Their Mixture in Montmorillonite Clay Hydrates

    KAUST Repository

    Kadoura, Ahmad Salim

    2016-05-26

    Molecular dynamics simulations were carried out to study the structural and transport properties of carbon dioxide, methane, and their mixture at 298.15 K in Na-montmorillonite clay in the presence of water. The simulations show that, the self-diffusion coefficients of pure CO2 and CH4 molecules in the interlayers of Na-montmorillonite decrease as their loading increases, possibly because of steric hindrance. The diffusion of CO2 in the interlayers of Na-montmorillonite, at constant loading of CO2, is not significantly affected by CH4 for the investigated CO2/CH4 mixture compositions. We attribute this to the preferential adsorption of CO2 over CH4 in Na-montmorillonite. While the presence of adsorbed CO2 molecules, at constant loading of CH4, very significantly reduces the self-diffusion coefficients of CH4, and relatively larger decrease in those diffusion coefficients are obtained at higher loadings. The preferential adsorption of CO2 molecules to the clay surface screens those possible attractive surface sites for CH4. The competition between screening and steric effects leads to a very slight decrease in the diffusion coefficients of CH4 molecules at low CO2 loadings. The steric hindrance effect, however, becomes much more significant at higher CO2 loadings and the diffusion coefficients of methane molecules significantly decrease. Our simulations also indicate that, similar effects of water on both carbon dioxide and methane, increase with increasing water concentration, at constant loadings of CO2 and CH4 in the interlayers of Na-montmorillonite. Our results could be useful, because of the significance of shale gas exploitation and carbon dioxide storage.

  11. Solubility of carbon dioxide in a eutectic mixture of choline chloride and glycerol at moderate pressures

    International Nuclear Information System (INIS)

    Highlights: ► The solubilities of carbon dioxide in a eutectic mixture of choline chloride and glycerol were measured. ► The pressure was up to 6.3 MPa. ► The temperature studied was (303.15 to 343.15) K. ► The measured data were reported as functions of temperature and pressure. ► The measured data were represented satisfactorily by the applied correlation. - Abstract: In this work, we present new measurements on the solubility of carbon dioxide in a deep eutectic solvent (DES) containing choline chloride and glycerol (1:2 mole ratio) over the temperature range (303.15 to 343.15) K and pressures up to 6.3 MPa. Experimental measurements were carried out in a thermogravimetric microbalance, and the effects of buoyancy on the measurements were accounted for. Results indicated that the solubility of the gas in the solvent increased almost linearly with pressure and decreased with increasing temperature. The dependence of the carbon dioxide solubility in the DES (in molality) on temperature and pressure were accurately represented by an extended Henry’s law model at an average absolute deviation of 1.4%.

  12. Synergetic effect of carbon nanopore size and surface oxidation on CO2 capture from CO2/CH4 mixtures

    OpenAIRE

    Furmaniak, Sylwester; KOWALCZYK, PIOTR; Terzyk, Artur P.; Gauden, Piotr A.; Harris , P. J. F.

    2013-01-01

    We have studied the synergetic effect of confinement (carbon nanopore size) and surface chemistry (the number of carbonyl groups) on CO2 capture from its mixtures with CH4 at typical operating conditions for industrial adsorptive separation (298 K and compressed CO2CH4 mixtures). Although both confinement and surface oxidation have an impact on the efficiency of CO2/CH4 adsorptive separation at thermodynamics equilibrium, we show that surface functionalization is the most important factor in ...

  13. Density, conductivity, viscosity, and excess properties of (pyrrolidinium nitrate-based Protic Ionic Liquid + propylene carbonate) binary mixture

    OpenAIRE

    Pires, J; Timperman, L.; Jacquemin, J.; A. Balducci; Anouti, M.

    2013-01-01

    Density, ?, viscosity, ?, and conductivity, s, measurements of binary mixtures containing the pyrrolidinium nitrate Protic Ionic Liquid (PIL) and propylene carbonate (PC), are determined at the atmospheric pressure as a function of the temperature from (283.15 to 353.15) K and within the whole composition range. The temperature dependence of both the viscosity and conductivity of each mixture exhibits a non-Arrhenius behaviour, but is correctly fitted by using the Vogel–Tamman–Fulcher (VTF) e...

  14. Sorption of a mixture of phenols in aqueous solution with activated carbon

    International Nuclear Information System (INIS)

    The main objective of this work is the sorption of an aqueous mixture of phenol-4 chloro phenol of different concentrations in a molar relationship 1:1 in activated carbon of mineral origin of different nets (10, 20 and 30) and to diminish with it its presence in water. The experimental results show that the removal capacity depends so much of the surface properties of the sorbent like of the physical and chemical properties of the sorbate. In all the cases it was observed that in the aqueous systems of low concentration the 4-chloro phenol are removed in an approximate proportion of 1.2-4 times greater to than phenol, however to concentrations but high both they are removed approximately in the same proportion. (Author)

  15. Preparation of Ammonia Adsorbent by Carbonizing and Activating Mixture of Biomass Material and Hygroscopic Salt

    Institute of Scientific and Technical Information of China (English)

    LONG Zhen; BU Xianbiao; LU Zhenneng; LI Huashan; MA Weibin

    2015-01-01

    We put forward a new and ingenious method for the preparation of a new adsorbent by soaking, carbonizing and activating the mixture of hygroscopic salt and biomass material. The new adsorbent has high porosity, uniform distribution and high content of CaCl2, and exhibits high adsorption performance. The ammonia uptake and specific cooling power (SCP) at 5 min adsorption time can reach as high as 0.19 g•g-1 and 793.9 W•kg-1, respectively. The concept of utilizing the biomass materials and hygroscopic salts as raw materials for the preparation of adsorbents is of practical interest with respect to the potential quantity of biomass materials around the world, indicating that there would be a new market for biomass materials.

  16. Acute toxicity of a mixture of copper and single-walled carbon nanotubes to Daphnia magna.

    Science.gov (United States)

    Kim, Ki T; Klaine, Stephen J; Lin, Sijie; Ke, Pu C; Kim, Sang D

    2010-01-01

    Nanomaterials released into the environment will interact with many materials including other contaminants. This may influence bioavailability and fate of both the nanoparticles and the other contaminants. The present study examined the effect of a combination of soluble copper and surface-modified single-walled carbon nanotubes (SWNTs) on Daphnia magna. Lysophosphatidylcholine (LPC) was used to modify the surface of SWNTs, reducing the surface hydrophobicity of the tubes and thereby producing a stable aqueous nanoparticle suspension. The toxicity of the nanoparticle-copper (Cu) mixture was determined to be additive. The addition of nontoxic concentration of LPC-SWNTs enhanced the uptake and toxicity of copper. Greater amounts of Cu were shown to accumulate in D. magna upon addition of 0.5 and 1.0 mg/L LPC-SWNTs. PMID:20821426

  17. Thermodynamic functions, freezing transition, and phase diagram of dense carbon-oxygen mixtures in white dwarfs

    International Nuclear Information System (INIS)

    Equations of state for dense carbon-oxygen (C-O) binary-ionic mixtures (BIM's) appropriate to the interiors of white dwarfs are investigated through Monte Carlo simulations, by solution of relevant integral equations and variational calculations in the density-functional formalism. It is thereby shown that the internal energies of the C-O BIM solids and fluids both obey precisely the linear mixing formulas. We then present an accurate calculation of the phase diagram associated with freezing transitions in such BIM materials, resulting in a novel prediction of an azeotropic diagram. Discontinuities of the mass density across the azeotropic phase boundaries are evaluated numerically for application to a study of white-dwarf evolution

  18. Liquid crystal nanocomposites produced by mixtures of hydrogen bonded achiral liquid crystals and functionalized carbon nanotubes

    Science.gov (United States)

    Katranchev, B.; Petrov, M.; Keskinova, E.; Naradikian, H.; Rafailov, P. M.; Dettlaff-Weglikowska, U.; Spassov, T.

    2014-12-01

    The liquid crystalline (LC) nature of alkyloxybenzoic acids is preserved after adding of any mesogenic or non-mesogenic compound through hydrogen bonding. However, this noncovalent interaction provokes a sizable effect on the physical properties as, e. g. melting point and mesomorphic states. In the present work we investigate nanocomposites, prepared by mixture of the eighth homologue of p-n-alkyloxybenzoic acids (8OBA) with single-walled carbon nanotubes (SWCNT) with the purpose to modify the optical properties of the liquid crystal. We exercise optical control on the LC system by inserting SWCNT specially functionalized by carboxylic groups. Since the liquid crystalline state combines order and mobility at the molecular (nanoscale) level, molecular modification can lead to different macroscopical nanocomposite symmetry. The thermal properties of the functionalized nanocomposite are confirmed by DSC analyses. The mechanism of the interaction between surface-treated nanoparticles (functionalized nanotubes) and the liquid crystal 8OBA bent- dimer molecules is briefly discussed.

  19. Gas Gain Measurement Of GEM-Foil In Argon-Carbon Dioxide Mixture

    International Nuclear Information System (INIS)

    Nuclear reaction measurement with radioactive beam at low energy plays an important role in nuclear astrophysics and nuclear structure. The trajectory of particle beams can be obtained by using an active gas target, multiple-sampling and tracking proportional chamber (MSTPC), as a proportional counter. Because of intensity of low energy radioactive beam, in the stellar reaction such as (α, p), (p, α), it is necessary to increase the gain for the counter. In this case, a gas electrons multiplier (GEM) foil will be used, so the proportional counter is called GEM-MSTPC. The efficient gas gain of GEM foils which relates to foil thickness and operating pressure was investigated with two type of the foils, 400 μm and 200 μm, in Argon (70%) + Carbon dioxide (30%) mixture. (author)

  20. Spectrographic determination of impurities in uranium tetrafluoride matrices

    International Nuclear Information System (INIS)

    A direct spectrographic method for the determination of UF4 impurities was developed. Investigations using spectrochemical carriers were carried out so to avoid uranium distillation, which as fluoride is much more volatile than the U3O8 refractory matrix. The best results were obtained by using a mixture of MgO and NaCl carriers in the proportion of 20% and 10%, respectively, with respect to UF4 matrix. An original spectrographic technique was introduced aiming to avoid the projection of sample particles outside the electrode during excitation. This new technique is based on the addition of a small quantity of a 0.5% gelatinous solution on the UF4 tablet. The precision of the method was studied for each element analysed. The variation coefficients are within the range of 10 of 20%

  1. In situ carbon and nitrogen dynamics in ryegrass-clover mixtures

    DEFF Research Database (Denmark)

    Rasmussen, J.; Eriksen, J.; Jensen, Erik Steen;

    2007-01-01

    .4% (±0.1, n=9). 15N-enriched compounds were not detected in percolating pore water, which may be caused by either dilution from irrigation or low availability of leachable N compounds. 14C was found solely as 14CO2 in the pore water indicating that dissolved organic carbon (DOC) did not originate from......Carbon (C) and nitrogen (N) dynamics in a third production year ryegrass–clover mixture were investigated in the field. Cylinders (diameter 29.7 cm) were installed to depths of 20, 40 and 60 cm and equipped with suction cups to collect percolating pore water. Ryegrass and clover leaves were cross......-labelled with 14C- and 15N-enriched urea and the fate of the two tracers was studied for 3 months during summer. Transfer of 14C occurred mainly from ryegrass to clover, whereas the largest transfer of 15N was in the opposite direction. The average transfer of N from clover was 40% (SE±3.1, n=9) of N in...

  2. Coordinated spectral and XRD analyses of magnesite-nontronite-forsterite mixtures and implications for carbonates on Mars

    Science.gov (United States)

    Bishop, Janice L.; Perry, Kaysea A.; Darby Dyar, M.; Bristow, Thomas F.; Blake, David F.; Brown, Adrian J.; Peel, Samantha E.

    2013-04-01

    Mineral detection on Mars largely relies on laboratory data of minerals and mineral mixtures. The objective of this study is to provide reflectance spectra in the visible/near-infrared (VNIR) and mid-IR regions, X-ray diffraction (XRD) data and Mössbauer spectra of a suite of carbonate, phyllosilicate and olivine mixtures in order to facilitate identification and characterization of these minerals on Mars. Remote sensing observations indicate that combinations of these minerals are present in ancient rocks on Mars around the Isidis Basin and in Gusev crater. Magnesite, nontronite, and forsterite size fractions spectra of mixtures. Analyses of the NIR band depths near 2.3, 2.5, 3.4, and 4 µm showed clear trends with carbonate abundance, although the data are not linear. Mixtures of magnesite and nontronite exhibited a band near 2.3 µm much closer to that observed for nontronite than that for magnesite. VNIR analyses of the mixtures indicated that a small amount of forsterite in any of the mixtures contributed a large increase in the broad ~1 µm band and, hence, the red slope characteristic of Fe2+-bearing minerals. Mid-IR mixture spectra were dominated by magnesite and forsterite, and nontronite was much more difficult to detect by mid-IR spectra in the mixtures. This could be related to why phyllosilicates are detected in many locations on Mars using data collected by the Compact Reconnaissance Imaging Spectrometer for Mars, but not detected using data collected by the Thermal Emission Spectrometer. Mössbauer spectroscopy is well suited for analyses of Fe2+- and Fe3+-bearing minerals, and modeling of the peak areas gave well-correlated trends for nontronite and forsterite abundances where abundant Fe was present. XRD full-pattern fitting analyses were performed on the magnesite-forsterite series, giving results within 6 wt % of the actual values, with a mean difference between actual and calculated values of 2.4 wt %. This study provides important laboratory

  3. Remediation of Nitrate-contaminated Groundwater by a Mixture of Iron and Activated Carbon

    Science.gov (United States)

    Huang, Guoxin; Liu, Fei; Jin, Aifang; Qin, Xiaopeng

    2010-11-01

    Nitrate contamination in groundwater has become a major environmental and health problem worldwide. The aim of the present study is to remediate groundwater contaminated by nitrate and develop potential reactive materials to be used in PRBs (Permeable Reactive Barriers). A new approach was proposed for abiotic groundwater remediation by reactive materials of iron chips and granular activated carbon particles. Batch tests were conducted and remediation mechanisms were discussed. The results show that nitrate decreases from 86.31 to 33.79 mgṡL-1 under the conditions of near neutral pH and reaction time of 1h. The combination of iron chips and activated carbon particles is cost-effective and suitable for further use as denitrification media in PRBs. Nitrogen species don't change significantly with the further increase in reaction time (>1 h). The iron-activated carbon-water-nitrate system tends to be steady-state. Small amounts of ammonium and nitrite (0.033-0.039 and 0.14-3.54 mgṡL-1, respectively) appear at reaction time from 0 h to 5 h. There is no substantial accumulation of nitrogen products in the system. The removal rate of nitrate only reaches 16.11% by sole iron chips at reaction time of 5 h, while 63.57% by the mixture of iron chips and activated carbon particles. There is significantly synergistic and promotive effect of mixing the two different types of materials on nitrate treatment. Fe/C ratio (1/1.5-1/2.5) doesn't cause dramatically different residual nitrate concentrations (24.09-26.70 mgṡL-1). Nitrate can't be limitlessly decreased with decreasing Fe/C ratio. The concomitant occurrences of chemical reduction, galvanic cell reaction, electrophoretic accumulation, chemical coagulation, and physical adsorption are all responsible for the overall nitrate removal by iron allied with activated carbon. To accurately quantify various nitrogen species, further studies on adsorption mechanisms of nitrite and nitrate are needed.

  4. Action of explosion on a substance: new modification of uranium tetrafluoride

    International Nuclear Information System (INIS)

    Two known modifications for uranium tetrafluoride are the α-form, stable under normal conditions, and the high-temperature β-modification. αUF4, a light green powder, was subjected to high pressures created by shock waves during an explosion. Properties of the resultant dark green material, γUF4, were compared with those of the original substance. The new modification had higher refractive indices, a significantly increased density, and an increase in dielectric penetration. X-ray-grams had less legible lines indicating the presence of defects. No significant changes in the IR-spectra were noted. A thermographic study discovered differences between the compressed and original samples

  5. Effect of titanium tetrafluoride, amine fluoride and fluoride varnish on enamel erosion in vitro

    OpenAIRE

    Vieira, A; Ruben, JL; Huysmans, MCDNJM

    2005-01-01

    This study aimed at evaluating the effect of 1 and 4% titanium tetrafluoride (TiF4) gels, amine fluoride (AmF) 1 and 0.25% and a fluoride varnish (FP) on the prevention of dental erosion. Two experimental groups served as controls, one with no pretreatment and another one pre-treated with a fluoride-free varnish (FP-blanco). Dental erosion was modelled using bovine enamel samples submitted to alternate cycles of acid exposure in citric acid and remineralization in artificial saliva. Calcium l...

  6. Protection of short-time enamel erosion by different tetrafluoride compounds

    OpenAIRE

    Wiegand, Annette; Laabs, Kolja A; Gressmann, Grit; Roos, Malgorzata; Magalhães, Ana C.; Attin, Thomas

    2008-01-01

    OBJECTIVE: This in vitro study aimed to analyse the protective effect of differently concentrated titanium (TiF(4)), zirconium (ZrF(4)) and hafnium (HfF(4)) tetrafluoride on enamel erosion. METHODS: Polished enamel surfaces of 36 bovine crowns were covered with tape leaving 4 enamel windows each 3mm in diameter exposed. The crowns were randomly assigned to six groups (each n=6) and pretreated with 4% TiF(4), 10% TiF(4), 4% ZrF(4), 10% ZrF(4), 4% HfF(4) or 10% HfF(4) for 4 min (first window), ...

  7. Reactions of Hot Cl38 Atoms in Mixtures of Carbon Tetrachloride with Aliphatic Alcohols

    International Nuclear Information System (INIS)

    Investigations of the chemical effects of nuclear reactions in binary systems are expected to yield much useful information. Study of the recoil processes of the halogen derivatives when the second component is suitably chosen and its concentration varied in a wide range might permit inferences to be made on the role and mechanism of the various stabilizing processes. Considering the results obtained with CCl4-Cl2, CCl4-SiCl4, CCl4-C6H6 and CCl4-c-hexane mixtures as well as the energy scavenger property of alcohol, it seemed of interest to study the contribution of the alcohols to the stabilization of hot Cl38. Chemical processes induced by hot Cl38 from the nuclear reaction Cl97 (n, γ)Cl38 were investigated in mixtures of CCl4-ROH (where R = CH3-, C2H5-, C3H7- and (CH3)2CH-). The irradiations were performed in the thermal column of the 2 MW VVRS reactor using rather short exposure times to keep the radiation chemical effects at negligible level. The organic fractions were separated from the inorganic ones by extraction and the former were analysed by gas chromatographic method. Total retention and the yield of the complete set of organic chlorine compounds were determined in terms of alcohol concentration. Some interesting results are that the yield of reaction products in which the OH radical of aliphatic alcohol has been replaced by Cl38 increases with increasing alcohol concentration with a simultaneous decrease in the labelled CCI4 yield and that, in addition to the monochlorine derivates with less carbon atoms than the alcohol molecule, a considerable amount of chloroform is formed with maximum yield at a given alcohol concentration. The relative contributions of the hot and the epithermal stabilization processes of energetic Cl38 and the mechanism of the various reactions are discussed. (author)

  8. Synthesis and characterization of poly lactic acid and multiwall carbon nano-tubes mixtures

    Science.gov (United States)

    Kumar LG, Santhosh; del A. Cardona, Rocío; Berríos-Soto, Melvin; Santiago-Avilés, Jorge J.

    2011-10-01

    The motivation for this study is to reproduce processing conditions which lead to the formation of photo or photoinduced thermal actuation, combined with inexpensive, environmentally friendly (easily degradable) materials. Commercially available polymer, poly lactic acid (PLA), was used in our studies. PLA is a well know biodegradable polymer naturally obtained from corn. PLA was received as a solid resin in pellet form and dissolved in 1:3 acetone/chloroform solutions, to achieve the proper electrospinning kinematic viscosity. Once in the liquid phase, the material was mixed with commercially available multi-walled carbon nanotubes (MWCNTs) at varying concentrations and dispersed by severe sonication. The mixtures was electrospun at room temperature using a home built electrospinning apparatus capable of depositing randomly oriented fiber mats or oriented fibers onto different substrates, ranging from oxidized silicon wafers, alumina squares or glass microscope slides. The fibers diameters and lengths are statistically distributed following a log-normal distribution and the mean and dispersion are controlled by spinning parameters. Once the fibers were electrospun, they were compositionally, morphologically and structurally characterized by thermal and gravimetric analysis (TGA/DTA), rheology, imaging using a focused Ion Beam Scanning Electron Microscope (IBSEM), and IR /Raman methodologies. These studies can be used to explore PLA-MWCNTs mixtures suitability in applications such as super-capacitor technology, which would enable us to pursue further research in this field, while focusing on improving the electro spinning conditions so as to be able to better anticipate fiber morphology to generate a consistent regime of fibers.

  9. Simulation of Multiphase Water-Carbon Dioxide Mixture Flows in Porous Media

    Science.gov (United States)

    Afanasyev, A. A.

    2012-04-01

    Two-phase models are widely used for simulation of CO2 storage in saline aquifers. These models support gaseous phase mainly saturated with CO2 and liquid phase mainly saturated with H2O (e.g. TOUGH2 code). For deep aquifers where CO2 injection may result a plume of supercritical CO2 compositional simulation approach must be applied. This approach originated from petrol reservoir simulation studies is based on a cubic equation of state and is also capable only of single-phase states and two-phase states of liquid-gas type. The goal of the present study lies in development of a new mathematical approach for compositional simulation of carbon sequestration processes. The approach is supposed to be capable both of single-phase and two-phase states of liquid-gas type as in classical models and also of two-phase states of liquid-liquid type and three-phase states at high pressure. The liquid-liquid states are formed by two liquids. The first liquid is mainly saturated with water while the second is mainly saturated with CO2. These thermodynamic equilibriums with liquefied CO2 phase can be detected experimentally (Takenouchi et. al., 1964). The three-phase states represent a composition of the two-phase states of liquid-gas and liquid-liquid types. The three phases are water and CO2 in liquid and gaseous states. As liquefied CO2 is negatively buoyant at high pressure the described states can result in non-classical hydrodynamic effects in the aquifer with CO2 sinking and consequently in non-classical structural trapping scenarios. The distinctive feature of the proposed approach lies in the methodology for mixture properties determination. Transport equations and Darcy law are solved together with calculation of the entropy maximum that is reached in thermodynamic equilibrium and determines the mixture composition. To define and solve the problem only one function - mixture thermodynamic potential - is required. The proposed approach was implemented in MUFITS (Multiphase

  10. Influence of carbon monoxide additions on the sensitivity of the dry hydrogen-air mixtures to detonation

    International Nuclear Information System (INIS)

    Under severe accident conditions of water cooled nuclear reactors the hydrogen-air detonation represents one of the most hazardous events which can result in the reactor containment damage. An important factor related with the measure of gas mixture detonability is the detonation cell size which correlates with the critical tube diameter and detonation initiation energy. A numerical kinetic study is presented of the influence of carbon monoxide admixtures (from 0 vol.% to 40 vol.%) upon the sensitivity (detonation cell size) of the dry hydrogen-air gas mixtures to detonation in post-accident containment atmosphere. (author). 3 refs., 3 figs

  11. Sorption of a phenols mixture in aqueous solution with activated carbon

    International Nuclear Information System (INIS)

    The constant population growth and the quick industrialization have caused severe damages to our natural aquifer resources for a great variety of organic and inorganic pollutants. Among these they are those phenol compounds that are highly toxic, resistant (to the degradation chemistry) and poorly biodegradable. The phenolic compounds is used in a great variety of industries, like it is the production of resins, nylon, plastifiers, anti-oxidants, oil additives, drugs, pesticides, colorants, explosives, disinfectants and others. The disseminated discharges or effluents coming from the industrial processes toward lakes and rivers are causing a growing adverse effect in the environment, as well as a risk for the health. Numerous studies exist on the phenols removal and phenols substituted for very varied techniques, among them they are the adsorption in activated carbon. This finishes it has been used successfully for the treatment of residual waters municipal and industrial and of drinking waters and it is considered as the best technique available to eliminate organic compounds not biodegradable and toxic present in aqueous solution (US EPA, 1991). However a little information exists on studies carried out in aqueous systems with more of a phenolic compound. The activated carbon is broadly used as adsorbent due to its superficial properties in the so much treatment of water as of aqueous wastes, adsorbent for the removal of organic pollutants. The main objective of this work is the adsorption of a aqueous mixture of phenol-4 chloro phenol of different concentrations in activated carbon of mineral origin of different meshes and to diminish with it their presence in water. The experiments were carried out for lots, in normal conditions of temperature and pressure. The experimental results show that the removal capacity depends so much of the superficial properties of the sorbent like of the physical properties and chemical of the sorbate. The isotherms were carried

  12. Microcrystalline dimension and total active surface area of carbon electrode from mixtures of pre-carbonized oil palm empty fruit bunches and green petroleum cokes

    International Nuclear Information System (INIS)

    Carbon pellets (CP) were prepared from the green pellets (GP) containing mixtures of pre-carbonized oil palm empty fruit bunches (SACG) and Green Petroleum Cokes (GPC), with the weight percentages (x) of SACG in the samples at 10 %, 30 %, 50 %, 70 % and 90 %. Carbonization process to produce the CP was conducted up to 900 degree Celsius using a multi steps heating profile. The interlayer spacing (d200 and d100), stack height (Lc), stack width (La,) and effective dimension L of the turbostratic crystallites (microcrystalline) in the CPs were estimated from X-ray diffraction data; d200, d100, La, L increased and Lc decreased with increasing weight percentage of SACG. The total surface area of active material of the CP (Atot) with thickness, t, estimated from Lc was found to follow the equation, Atot = [4.8086 - 0.0083x]1010 t, indicating a significant influence of the SACG content in the mixture of the green body. (author)

  13. Dipolar Self-Assembling in Mixtures of Propylene Carbonate and Dimethyl Sulfoxide as Revealed by the Orientational Entropy.

    Science.gov (United States)

    Płowaś, Iwona; Świergiel, Jolanta; Jadżyn, Jan

    2016-08-18

    This article presents the results of static dielectric studies performed on mixtures of two strongly polar liquids important from a technological point of view: propylene carbonate (PC) and dimethyl sulfoxide (DMSO). The dielectric data were analyzed in terms of the molar orientational entropy increment induced by the probing electric field. It was found that the two polar liquids in the neat state reveal quite different molecular organization in terms of dipole-dipole self-assembling: PC exhibits a dipolar coupling of the head-to-tail type, whereas in DMSO one observes extreme restriction of dipolar association in any form. In PC + DMSO mixtures, the disintegration of the dipolar ensembles of PC molecules takes place and the progress of that process is strictly proportional to the concentration of DMSO. The static permittivity of mixtures of such differently self-organized liquids exhibits a positive deviation from the additive rule and the deviation develops symmetrically within the concentration scale. PMID:27458791

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

    Science.gov (United States)

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

    2010-01-01

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

  15. An Experimental Study of Mixture Corrosion Effects of Carbonate Rocks in the Transitional Zone of Littoral Karst Areas

    Institute of Scientific and Technical Information of China (English)

    陈鸿汉; 邹胜章; 朱远峰; 陈从喜

    2001-01-01

    The mechanism for development of littoral karst differs from that of inland karst, and the mixture corrosion effects are one of the most important factors that control the development of littoral karst. Through seven groups of static experiments carried out in a closed CO2-H2O system, basic conclusions can be drawn as follows: (1) the basic law of corrosion process in a transitional zone of seawater-freshwater in littoral karst areas is identical with that in the fresh water,i.e., the lithologic characteristics and rock structure are the main factors which control the development of littoral karst; (2)the mixture corrosion rate of the carbonate rock in the above transitional zone is faster than that in fresh water or seawater;(3) the mechanism for development of carbonate rocks differs at various pressures of CO2 in a transitional zone in littoral karst areas.``

  16. Electrical Conductivity Of Carbon Pellets Prepared From Mixtures Of Pyropolymers From Oil Palm Bunches and Petroleum Green Coke

    Science.gov (United States)

    Deraman, M.; Awitdrus, Talib, I. A.; Omar, R.; Jumali, M. H.; Ishak, M. M.; Saad, S. K. M.; Taer, E.; Saman, M. M.; Farma, R.; Yunus, R. M.

    2010-12-01

    Green pellets (GPs), prepared at different compression pressures (cs = 6, 7.5 and 12 metric tonne) from mixtures containing self-adhesive carbon grains (sacg) from the oil palm empty fruit bunch (EFB) and different percentages (pr = 0 to 90%) of a non self-adhesive powder of petroleum green coke (ppgc), were carbonized (800° C) and activated with CO2 to produce carbon pellets (CPs). The measured electrical conductivity (σ) of the CP for all cs showed a curve having a minimum value at pr around 50%, indicating that the conducting phase displays a nonlinear σ- pr relationship. A significant increase in the σ due to CO2 activation was observed. For a sufficienctly high cs, an existence of a pr range in which the σ varies linearly with the density was also observed. These results provide some new information for modifying the electrical conductivity of carbon derived from the sacg from EFB or other types of biomass.

  17. A molecular-based approach to the thermodynamics of aqueous solutions: binary mixture of water and carbon dioxide.

    Science.gov (United States)

    Jirsák, J; Škvor, J

    2015-05-20

    A simple model and theory of molecular fluids is applied to a binary mixture of water and carbon dioxide. An approach based on the perturbation theory is followed using a reference system of so-called pseudo-hard bodies for water and hard triatomics for carbon dioxide. Pseudo-hard bodies bear the traits of the non-additive nature of association supplementing the common excluded volume effect. The reference term is parametrized using Monte Carlo simulation data on the compressibility factor. After adding a simple mean-field term to the reference equation, fluid phase equilibria are qualitatively reproduced. PMID:25923412

  18. A molecular-based approach to the thermodynamics of aqueous solutions: binary mixture of water and carbon dioxide

    International Nuclear Information System (INIS)

    A simple model and theory of molecular fluids is applied to a binary mixture of water and carbon dioxide. An approach based on the perturbation theory is followed using a reference system of so-called pseudo-hard bodies for water and hard triatomics for carbon dioxide. Pseudo-hard bodies bear the traits of the non-additive nature of association supplementing the common excluded volume effect. The reference term is parametrized using Monte Carlo simulation data on the compressibility factor. After adding a simple mean-field term to the reference equation, fluid phase equilibria are qualitatively reproduced. (paper)

  19. Differentiation of Chemical Components in a Binary Solvent Vapor Mixture Using Carbon/Polymer Composite-Based Chemiresistors

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Sanjay V.; Jenkins, Mark W.; Hughes, Robert C.; Yelton, W. Graham; Ricco, Antonio J.

    1999-07-19

    We demonstrate a ''universal solvent sensor'' constructed from a small array of carbon/polymer composite chemiresistors that respond to solvents spanning a wide range of Hildebrand volubility parameters. Conductive carbon particles provide electrical continuity in these composite films. When the polymer matrix absorbs solvent vapors, the composite film swells, the average separation between carbon particles increases, and an increase in film resistance results, as some of the conduction pathways are broken. The adverse effects of contact resistance at high solvent concentrations are reported. Solvent vapors including isooctane, ethanol, dlisopropyhnethylphosphonate (DIMP), and water are correctly identified (''classified'') using three chemiresistors, their composite coatings chosen to span the full range of volubility parameters. With the same three sensors, binary mixtures of solvent vapor and water vapor are correctly classified, following classification, two sensors suffice to determine the concentrations of both vapor components. Polyethylene vinylacetate and polyvinyl alcohol (PVA) are two such polymers that are used to classify binary mixtures of DIMP with water vapor; the PVA/carbon-particle-composite films are sensitive to less than 0.25{degree}A relative humidity. The Sandia-developed VERI (Visual-Empirical Region of Influence) technique is used as a method of pattern recognition to classify the solvents and mixtures and to distinguish them from water vapor. In many cases, the response of a given composite sensing film to a binary mixture deviates significantly from the sum of the responses to the isolated vapor components at the same concentrations. While these nonlinearities pose significant difficulty for (primarily) linear methods such as principal components analysis, VERI handles both linear and nonlinear data with equal ease. In the present study the maximum speciation accuracy is achieved by an array

  20. UV-Vis, infrared, and mass spectroscopy of electron irradiated frozen oxygen and carbon dioxide mixtures with water

    International Nuclear Information System (INIS)

    Ozone has been detected on the surface of Ganymede via observation of the Hartley band through the use of ultraviolet spectroscopy and is largely agreed upon to be formed by radiolytic processing via interaction of magnetospheric energetic ions and/or electrons with oxygen-bearing ices on Ganymede's surface. Interestingly, a clearly distinct band near 300 nm within the shoulder of the UV-Vis spectrum of Ganymede was also observed, but currently lacks an acceptable physical or chemical explanation. Consequently, the primary motivation behind this work was the collection of UV-Vis absorption spectroscopy of ozone formation by energetic electron bombardment of a variety of oxygen-bearing ices (oxygen, carbon dioxide, water) relevant to this moon as well as other solar system. Ozone was indeed synthesized in pure ices of molecular oxygen, carbon dioxide and a mixture of water and oxygen, in agreement with previous studies. The Hartley band of the ozone synthesized in these ice mixtures was observed in the UV-Vis spectra and compared with the spectrum of Ganymede. In addition, a solid state ozone absorption cross section of 6.0 ± 0.6 × 10–17 cm2 molecule–1 was obtained from the UV-Vis spectral data. Ozone was not produced in the irradiated carbon dioxide-water mixtures; however, a spectrally 'red' UV continuum is observed and appears to reproduce well what is observed in a large number of icy moons such as Europa.

  1. Mixtures of ionic liquid and organic carbonate as electrolyte with improved safety and performance for rechargeable lithium batteries

    International Nuclear Information System (INIS)

    Highlights: → Mixtures of PC, PYR14TFSI and LiTFSI as electrolyte for lithium-ion batteries. → Mixtures with a high ionic liquid (IL) content are non-flammable. → Al corrosion potential is shifted to higher potentials by the addition of IL. → Cycling stability of a Li/LiFePO4 cell at 60 oC is improved by the addition of IL. - Abstract: In this paper we report the results of physical-chemical and electrochemical investigations performed on ternary mixtures of the room temperature ionic liquid (IL) N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI), propylene carbonate (PC), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as electrolyte for lithium-ion batteries. The thermal stability, ionic conductivity, viscosity and electrochemical stability windows of all considered mixtures were investigated and compared with those of electrolytes based on the pure PYR14TFSI and PC. The mixtures were also used as electrolyte in combination with LiFePO4-based electrodes. The specific capacity and cycling stability of these systems were investigated at different C-rates, both at room temperature and 60 oC.

  2. The redox combustion of carbon monoxide for recovering pure carbon dioxide by using molten (Na+,K+)2(CO32-,SO42-) mixtures.

    Science.gov (United States)

    Shimano, Satoshi; Asakura, Shukuji

    2006-06-01

    Large-scale combustion systems, such as thermal power plants, emit large amounts of carbon dioxide, which can increase global warming. A molten salt redox combustion system was proposed to recover pure carbon dioxide exhausted from the combustion of fossil fuels. This system is composed of two successive processes by using reactions occurring in a molten salt. The molten salt is the mixture of the molten alkali metal sulfates and carbonates. The sulfate ions oxidize the fuels in first processes, being changed to reductive species such as sulfide ions. In this process, carbon dioxide and water are exclusively exhausted. The reductive species of sulfur compounds are oxidized to regenerate the sulfate ions by air in the second process. In this study, these above two processes were tried by using molten [(Na(+))(0.5),(K(+))(0.5)](2)[(CO(3)(2-))(0.9),(SO(4)(2-))(0.1)] alternatively. The oxidation of carbon monoxide as fuel by sulfate ions and the regeneration of sulfate ions by air were investigated in the temperature range of 700-950 degrees C, respectively. These reactions were exothermic. The rate of the regeneration of the sulfate ions was extremely high. During the oxidation of carbon monoxide, the reaction was first order in carbon monoxide with an activation energy of 101 kJ mol(-1). The optimum condition to recover pure carbon dioxide on practical operation was discussed. PMID:16337672

  3. High-pressure phase behaviour of poly(D-lactic acid), trichloromethane, and carbon dioxide ternary mixture systems

    International Nuclear Information System (INIS)

    Highlights: • The high pressure phase behaviour of poly(D-lactic acid), trichloromethane and carbon dioxide ternary mixtures was measured. • The experimental data shows the characteristics of the LCST behaviour of (polymer + solvent + gas) systems. • The hybrid equation of state for the (polymer + carbon dioxide) system was used to correlate the experimental data. - Abstract: The high pressure phase behaviour of poly(D-lactic acid) (Mw = 359,000), trichloromethane, and carbon dioxide ternary mixture systems is presented in this study. Cloud and bubble point pressures were measured using a variable volume view cell at temperatures (313.15 to 363.15) K and pressures up to 33.6 MPa. The hybrid equation of state for the polymer-carbon dioxide system was used to correlate the experimental results. The van der Waals one-fluid mixing rule with three adjustable binary interaction parameters was used for all correlations. The binary parameters were optimised using the simplex method algorithm

  4. Solubility selective membrane materials for carbon dioxide removal from mixtures with light gases

    Science.gov (United States)

    Lin, Haiqing

    Membrane technology has attracted interest for the selective removal of carbon dioxide from mixtures with light gases such as H2, CH4 and N2. While conventional structure-property correlations have focused mainly on improving the separation performance by increasing polymer size sieving ability (i.e., diffusivity selectivity), this project explores the possibility of harnessing favorable interactions between CO 2 and polymers containing polar groups to improve permeability/selectivity properties. Ether oxide groups are discovered to be among the best moieties known to interact with CO2, leading to high CO2 solubility and CO2/light gas solubility selectivity, while still providing polymer chain flexibility, leading to high CO2 diffusivity and favorable CO2/H2 diffusivity selectivity. Poly(ethylene oxide) (PEO) has a high concentration of ether oxygen groups and exhibits high CO2/light gas selectivities. However, gas permeability is low due to the high crystallinity in PEO. Crosslinking and introduction of short chain branching are efficient methods to inhibit crystallization. Three series of crosslinked poly(ethylene oxide) rubbers have been prepared using prepolymer solutions containing: (1) poly(ethylene glycol) diacrylate (PEGDA) and H2O, (2) PEGDA and poly(ethylene glycol) methyl ether acrylate (PEGMEA), and (3) PEGDA and poly(ethylene glycol) acrylate (PEGA). Independent of the prepolymer composition, all of these polymers have similar ethylene oxide (EO) content (approximately 82 wt.%). Crosslink density decreases with decreasing PEGDA content in the prepolymer solution, which is estimated from water swelling experiments and/or dynamic mechanical testing and has essentially no effect on gas transport properties. Increasing PEGMEA content increases the average size of free volume elements, resulting in a decreased glass transition temperature, and increased CO 2 permeability and CO2/H2 selectivity. In contrast, the presence of PEGA or water has a negligible

  5. Transport properties of binary mixtures of carbon dioxide and 1-butyl-3-methylimidazolium hexafluorophosphate studied by transient grating spectroscopy.

    Science.gov (United States)

    Demizu, Masashi; Terazima, Masahide; Kimura, Yoshifumi

    2008-10-01

    Transient grating spectroscopy was applied to measurements of sound velocity and thermal diffusivity in binary mixture solutions of carbon dioxide (CO(2)) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF(6)]) along the saturated line of CO(2) at 40 degrees C up to 20.0 MPa. The sound velocity decreased more than 10% by increasing the pressure to 10 MPa, and the pressure effect was very small above 10 MPa. The change in the thermal diffusivity was small. The translational diffusion coefficients of carbon monoxide, diphenylacetylene (DPA), and diphenylcyclopropenone (DPCP) were also determined. The diffusion coefficients increased up to 10 MPa, and the pressure effect was almost saturated above 10 MPa. The pressure dependence of the diffusion coefficients of DPCP and DPA was larger than that of carbon monoxide. The results are discussed in relation with the viscosity change caused by applying pressure. PMID:18845895

  6. Joining of CBN abrasive grains to medium carbon steel with Ag-Cu/Ti powder mixture as active brazing alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ding, W.F. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)]. E-mail: dingwf2000@vip.163.com; Xu, J.H. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Shen, M. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Su, H.H. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Fu, Y.C. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Xiao, B. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2006-08-25

    In order to develop new generation brazed CBN grinding wheels, the joining experiments of CBN abrasive grains and medium carbon steel using the powder mixture of Ag-Cu alloy and pure Ti as active brazing alloy are carried out at elevated temperature under high vacuum condition. The relevant characteristics of the special powder mixture, the microstructure of the interfacial region, which are both the key factors for determining the joining behavior among the CBN grains, the filler layer and the steel substrate, are investigated extensively by means of differential thermal analysis (DTA), scanning electron microscope (SEM) and energy dispersion spectrometer (EDS), as well X-ray diffraction (XRD) analysis. The results show that, similar to Ag-Cu-Ti filler alloy, Ag-Cu/Ti powder mixture exhibits good soakage capability to CBN grains during brazing. Moreover, Ti in the powder mixture concentrates preferentially on the surface of the grains to form a layer of needlelike Ti-N and Ti-B compounds by chemical metallurgic interaction between Ti, N and B at high temperature. Additionally, based on the experimental results, the brazing and joining mechanism is deeply discussed in a view of thermodynamic criterion and phase diagram of Ti-B-N ternary system.

  7. Inhibition of the ultrasonic microjet-pits on the carbon steel in the particles-water mixtures

    Directory of Open Access Journals (Sweden)

    Dayun Yan

    2015-07-01

    Full Text Available In the incubation period of ultrasonic cavitation, due to the impact of microjets on the material surface, the needle-like microjet-pits are formed. Because the formation of microjet-pits relates with the evolution of cavitation erosion on engineering materials, corresponding study will promote the understanding on the mechanism of cavitation erosion. However, little study on the microjet-pits has been carried out, especially in the particles-water mixture. In this study, we firstly demonstrated the microjet-pits on the carbon steel would be significantly inhibited by Al particles in water. Such inhibition effect indicated that particular particles might not only provide growth sites for cavitation bubbles but also affect the collapse of cavitation bubbles near a solid surface. Our study deepened the understanding on the ultrasonic cavitation erosion in the particles-water mixture.

  8. Fluid phase equilibria of the reaction mixture during the selective hydrogenation of 2-butenal in dense carbon dioxide

    DEFF Research Database (Denmark)

    Musko, Nikolai; Jensen, Anker Degn; Baiker, Alfons;

    2012-01-01

    performed using a 5wt% Pd on activated carbon in custom-designed high pressure autoclaves at 323K. The Cubic-Plus-Association (CPA) equation of state was employed to model the phase behaviour of the experimentally studied systems. CPA binary interaction parameters were estimated based on the experimental...... vapour–liquid or liquid–liquid equilibria data available in the literature. No experimental data for the CO2–2-butenal binary system were available in the literature; therefore, the bubble points of this mixture of varying composition at three different temperatures were measured in a high-pressure view...... in the so-called “expanded liquid” region, which is located near the critical point of the reacting mixture. It was also found that in this point the hydrogen concentration achieved its maximum in the CO2-expanded phase. Furthermore, the pressure – temperature regions where the multicomponent...

  9. Heated uranium tetrafluoride target system to release non-rare gas fission products for the TRISTAN isotope separator

    International Nuclear Information System (INIS)

    The development of a heated uranium tetrafluoride target system for the TRISTAN isotope separator to release non-rare gas fission products is presented. Off-line experiments indicated that fluorides of As, Se, Br, Kr, Zr, Nb, Mo, Tc, Ru, Sb, Te, I and Xe could be volatilized, but except for Br, Kr, I and Xe, none of these elements was observed after mass separation in the on-line experiments. The results of the on-line experiments indicated a very low level of hydride contamination at ambient temperature and consequently, uranium tetrafluoride replaced uranyl stearate as the primary gaseous fission product target. Possible reasons for the failure of the heated target system to yield non-rare gas activities are discussed and suggestions for designing a new heated target system are presented

  10. Equation of state of initially liquid carbon monoxide and nitrogen mixture

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The modified liquid perturbation variational theory and the improved vdW-1f model were applied to calculating the equation of the state of liquid CO-N2 mixture with the ratio of 1:1, 4:1 and 1:4, respectively, in the shock pressure range of 9-49 GPa. It was shown that the calculated result for CO-N2 mixture with the ratio of 1:1 is well consistent with the earlier experimental data. The thermodynamics equilibrium, chemical equilibrium and phase equilibrium were all considered in detail. It was found that Hugoniot of liquid CO-N2 mixture is moderately softened in the pressure range of 20-30 GPa and 30-49 GPa for different initial proportions, and that the Hugoniot is more softened in the latter pressure range, which means that the structural phase transition occurs near 20 GPa and 30 GPa. Since the shock pro-ductions may absorb a plenty of systematic energy, the shock temperature and pressure decline compared with the case of no chemical reaction. Pressures and temperatures increase gradually with the increase in the mole fraction of nitrogen composition. The results for the 1:1 CO-N2 mixture lie in the middle of two others. Therefore, it was shown that the modified Lorentz-Berthelor rule used in the scheme is effective to study shock-compression properties of liquid CO-N2 mixture under high temperatures and high pressures.

  11. Inductive effect produced by a mixture of carbon source in the production of gibberellic acid by Gibberella fujikuroi.

    Science.gov (United States)

    Rios-Iribe, Erika Y; Flores-Cotera, Luis B; Chávira, Mario M González; González-Alatorre, Guillermo; Escamilla-Silva, Eleazar M

    2011-06-01

    Gibberellic acid has been known since 1954 but its effect on rice still remains very important in the agricultural world. Gibberellic acid (GA3) is the main secondary metabolite produced by the Gibberella fujikuroi fungus. This hormone is of great importance in agriculture and the brewing industry, due to its fast and strong effects at low concentrations (μg) on the processes of growth stimulation, flowering, stem elongation, and germination of seeds, among others. Plant promoters of growth production such as the gibberellins, especially the GA3 are a priority in obtaining better harvests in the agricultural area and by extension, improving the food industry. Three routes to obtaining GA3 have been reported: extraction from plants, chemical synthesis and microbial fermentation. The latter being the most common method used to produce GA3. In this investigation, glucose-corn oil mixture was used as a carbon source on the basis of 40 g of carbon in a 7 L stirred tank bioreactor. A pH of 3.5, 29°C, 600 min(-1) agitation and 1 vvm aeration were maintained and controlled with a biocontroller connected to the bioreactor, throughout the entire culture time. The carbon source mixture affected the fermentation time as well as the production of the GAs. The production of 380 mg GA3L(-1) after 288 h of fermentation was obtained when the glucose-corn oil mixture was employed contrasting the 136 mg GA3L(-1) at 264 h of culture when only glucose was used. PMID:25187149

  12. Graphitized carbon in gas-liquid-solid chromatography and gas chromatography/mass spectrometric analysis of high boiling hydrocarbon mixtures

    International Nuclear Information System (INIS)

    Gas--liquid--solid chromatography (GLSC) employing a poly(phenyl ether) (PPE 20) liquid phase on graphitized carbon black (GCB) is applicable to the analyses of crude oils and distillates of sedimentary rocks. The elution of C4 to C40 hydrocarbons which consist of n-alkanes, isoprenoid-type alkanes, steranes, olefins, and aromatic hydrocarbons can be handled in a single GC run. A GLSC column in tandem with a mass spectrometer provides an excellent means for the identification of geochemically significant organic compounds in complex natural mixtures. 8 figures, 4 tables

  13. Carbon-13 isotopic selectivity in the infrared multiphoton photolysis of CF2Cl2-O2 mixtures

    International Nuclear Information System (INIS)

    The infrared multiphoton chemistry of CF2Cl2-O2 mixtures has been studied at laser frequencies where the product CF2O is highly enriched in carbon-13 yield. Yield enhancements with no loss of isotopic selectivity are attributed to suppression of radical-atom recombination reactions. It is demonstrated that addition of up to 60 Torr of either excess O2 or N2 suppresses a thermal, non-selective channel important at higher fluences. A selectivity factor greater than 30 is observed for 4 Torr CF2Cl2 in the presence of 80 Torr of oxygen

  14. N/sub 2/O formation from an NO-SO/sub 2/ gaseous-mixture over activated carbon fibres at 303 K

    Energy Technology Data Exchange (ETDEWEB)

    Imai, Jun; Ozeki, Sumio; Suzuki, Takaomi; Kaneko, Katsumi

    1989-06-01

    /alpha/-FeOOH-dispersed activated carbon fibres (ACFs) show good adsorption characteristics for NO and SO/sub 2/ near room temperature. Studies of the reaction and adsorption of NO and SO/sub 2/ from their gaseous mixture on activated carbon fibres at 303 K by i.r. spectroscopy showed the formation of N/sub 2/O. (author).

  15. Mixture of ionic liquid and carbon nanotubes: comparative studies of the structural characteristics and dispersion of the aggregated non-bundled and bundled carbon nanotubes.

    Science.gov (United States)

    Mohammadi, Morteza; Foroutan, Masumeh

    2013-02-21

    In this work, the two mixtures of ionic liquid 1-n-propyl-4-amino-1,2,4-triazolium bromide and each type of the aggregated single-walled carbon nanotubes (SWCNTs), i.e. bundled SWCNTs and non-bundled, were investigated using molecular dynamics (MD) simulations. The structural characteristics of a SWCNT in the ionic liquid (IL) were examined by analyzing the radial distribution functions and the results show that the nearest IL cations to the SWCNT surface can approach it from three different positions. Also, the possibility of the dispersion of the bundled SWCNTs containing three and seven carbon nanotubes was investigated. The obtained results showed that under the investigated conditions, the IL cannot disperse the bundled SWCNTs, but it can disperse six and seven aggregated non-bundled ones. Moreover, we investigated the underlying dispersion mechanism of the aggregated SWCNTs in the IL, using MD simulations. The self diffusion coefficients and transport numbers of the cations and anions were computed in the systems containing pure IL, the mixtures of IL and one, six and seven non-bundled SWCNTs and the systems containing IL and bundled SWCNTs with three and seven carbon nanotubes. The obtained results showed that the diffusion coefficients and the transport numbers of the cations are more than anions in all mentioned systems. PMID:23318467

  16. Soft cutting of single-wall carbon nanotubes by low temperature ultrasonication in a mixture of sulfuric and nitric acids

    International Nuclear Information System (INIS)

    To decrease single-wall carbon nanotube (SWCNT) lengths to a value of 100–200 nm, aggressive cutting methods, accompanied by a high loss of starting material, are frequently used. We propose a cutting approach based on low temperature intensive ultrasonication in a mixture of sulfuric and nitric acids. The method is nondestructive with a yield close to 100%. It was applied to cut nanotubes produced in three different ways: gas-phase catalysis, chemical vapor deposition, and electric-arc-discharge methods. Raman and Fourier transform infrared spectroscopy were used to demonstrate that the cut carbon nanotubes have a low extent of sidewall degradation and their electronic properties are close to those of the untreated tubes. It was proposed to use the spectral position of the far-infrared absorption peak as a simple criterion for the estimation of SWCNT length distribution in the samples. (paper)

  17. Adsorption and Desorption of Carbon Dioxide and Water Mixtures on Synthetic Hydrophobic Carbonaceous Adsorbents

    Science.gov (United States)

    Finn, John E.; Harper, Lynn D. (Technical Monitor)

    1994-01-01

    Several synthetic carbonaceous adsorbents produced through pyrolysis of polymeric materials are available commercially. Some appear to have advantages over activated carbon for certain adsorption applications. In particular, they can have tailored hydrophobicities that are significantly greater than that of activated carbon, while moderately high surfaces areas are retained. These sorbents are being investigated for possible use in removing trace contaminants and excess carbon dioxide from air in closed habitats, plant growth chambers, and other applications involving purification of humid gas streams. We have analyzed the characteristics of a few of these adsorbents through adsorption and desorption experiments and standard characterization techniques. This paper presents pure and multicomponent adsorption data collected for carbon dioxide and water on two synthetic carbonaceous adsorbents having different hydrophobicities and capillary condensation characteristics. The observations are interpreted through consideration of the pore structure and surface chemistry of the solids and interactions between adsorbed carbon dioxide, water, and the solvent gas.

  18. Accurate (p, ρ, T) data for two new (carbon dioxide + nitrogen) mixtures from (250 to 400) K at pressures up to 20 MPa

    International Nuclear Information System (INIS)

    Highlights: ► New (p, ρ, T) data of two mixtures of nitrogen and carbon dioxide are reported. ► Experimental data show a disagreement with the equation of state at low temperatures and high pressures. ► Relative deviations in density increase with the carbon dioxide molar fraction of the mixture. ► Only relative deviations at pressures below 10 MPa are within a 0.1% band. - Abstract: Recently our group published a set of (p, ρ, T) data for two (carbon dioxide + nitrogen) mixtures with a low carbon dioxide content (xCO2=0.10,0.15). These data showed larger relative deviations from the GERG-2008 equation of state than expected, specially at low temperatures, high pressures, and for the mixture with higher carbon dioxide content (xCO2=0.15). In order to analyze whether the mentioned deviations from the equation of state increase with the carbon dioxide content, it was decided to measure the (p, ρ, T) behavior of two additional mixtures with higher carbon dioxide molar fractions (xCO2=0.20,0.50). The new experimental data show again an appreciable disagreement with the GERG-2008 equation of state at low temperatures and high pressures. Relative deviations, which depend on temperature, arise to 0.4% at 250 K and 20 MPa and to 0.24% at 275 K and 20 MPa for the xCO2=0.20 and xCO2=0.50 mixture, respectively. Second virial coefficients are calculated for the two new mixtures presented in this work and also for those presented in our previous paper.

  19. Electrolyte Mixtures Based on Ethylene Carbonate and Dimethyl Sulfone for Li-Ion Batteries with Improved Safety Characteristics.

    Science.gov (United States)

    Hofmann, Andreas; Migeot, Matthias; Thißen, Eva; Schulz, Michael; Heinzmann, Ralf; Indris, Sylvio; Bergfeldt, Thomas; Lei, Boxia; Ziebert, Carlos; Hanemann, Thomas

    2015-06-01

    In this study, novel electrolyte mixtures for Li-ion cells are presented with highly improved safety features. The electrolyte formulations are composed of ethylene carbonate/dimethyl sulfone (80:20 wt/wt) as the solvent mixture and LiBF4 , lithium bis(trifluoromethanesulfonyl)azanide, and lithium bis(oxalato)borate as the conducting salts. Initially, the electrolytes are characterized with regard to their physical properties, their lithium transport properties, and their electrochemical stability. The key advantages of the electrolytes are high flash points of >140 °C, which enhance significantly the intrinsic safety of Li-ion cells containing these electrolytes. This has been quantified by measurements in an accelerating rate calorimeter. By using the newly developed electrolytes, which are liquid down to T=-10 °C, it is possible to achieve C-rates of up to 1.5 C with >80 % of the initial specific capacity. During 100 cycles in cell tests (graphite||LiNi1/3 Co1/3 Mn1/3 O2 ), it is proven that the retention of the specific capacity is >98 % of the third discharge cycle with dependence on the conducting salt. The best electrolyte mixture yields a capacity retention of >96 % after 200 cycles in coin cells. PMID:25950145

  20. Novel electrolyte mixtures based on dimethyl sulfone, ethylene carbonate and LiPF6 for lithium-ion batteries

    Science.gov (United States)

    Hofmann, Andreas; Hanemann, Thomas

    2015-12-01

    In this study, novel electrolyte mixtures for Li-ion cells are presented which are composed of ethylene carbonate/dimethyl sulfone (80:20 wt./wt.) as a solvent mixture and LiPF6, lithium bis(oxalato)borate and lithium difluoro(oxalato)borate as conducting salts. The main advantages of the solvent mixture are high flash points of >140 °C which enhance the intrinsic safety of Li-ion cells while maintaining good cell performance above 0-5 °C. The movability of the lithium ions in the electrolyte is investigated via programmed current derivative chronopotentiometry. It is found that pure electrolyte properties cannot necessarily predict the electrolyte behavior in real Li-ion cells but the complex interplay between electrolytes, electrode materials and separators has to be taken into account. Using the newly developed electrolytes, it is possible to achieve C-rates up to 1.5C with >80% of the initial specific discharge capacity (25 °C). Within 200 cycles during one month in cell tests (C||NMC) it is proven that the retention of the specific capacity is >98% of the third discharge cycle in dependence of the conducting salt.

  1. Response of electrochemical oxygen sensors to inert gas-air and carbon dioxide-air mixtures: measurements and mathematical modelling.

    Science.gov (United States)

    Walsh, P T; Gant, S E; Dowker, K P; Batt, R

    2011-02-15

    Electrochemical oxygen gas sensors are widely used for monitoring the state of inertisation of flammable atmospheres and to warn of asphyxiation risks. It is well established but not widely known by users of such oxygen sensors that the response of the sensor is affected by the nature of the diluent gas responsible for the decrease in ambient oxygen concentration. The present work investigates the response of electrochemical sensors, with either acid or alkaline electrolytes, to gas mixtures comprising air with enhanced levels of nitrogen, carbon dioxide, argon or helium. The measurements indicate that both types of sensors over-read the oxygen concentrations when atmospheres contain high levels of helium. Sensors with alkaline electrolytes are also shown to underestimate the severity of the hazard in atmospheres containing high levels of carbon dioxide. This deviation is greater for alkaline electrolyte sensors compared to acid electrolyte sensors. A Computational Fluid Dynamics (CFD) model is developed to predict the response of an alkaline electrolyte, electrochemical gas sensor. Differences between predicted and measured sensor responses are less than 10% in relative terms for nearly all of the gas mixtures tested, and in many cases less than 5%. Extending the model to simulate responses of sensors with acid electrolytes would be straightforward. PMID:21112151

  2. Phase behaviour of the ternary mixture system of poly(L-lactic acid), dichloromethane and carbon dioxide

    International Nuclear Information System (INIS)

    Highlights: ► The high pressure phase behaviour of poly(L-lactic acid), dichloromethane and carbon dioxide ternary mixtures was measured. ► The experimental data shows the characteristics of the LCST behaviour of polymer–solvent–gas systems. ► The experimental data correlation was performed using the hybrid EOS. - Abstract: In this study, the high pressure phase behaviour of poly(L-lactic acid) (M = 312,000), dichloromethane and carbon dioxide ternary mixtures was studied using a variable volume view cell at temperatures ranging from 313.15 K to 363.15 K and pressures of up to 30.0 MPa as functions of temperature and the CO2/dichloromethane mass ratio at poly(L-lactic acid) weight fractions of 1.0%, 2.5% and 3.0%. The experimental results were correlated with the hybrid equation of state for the CO2-polymer system using the van der Waals one-fluid mixing rule with three adjustable binary interaction parameters.

  3. Comparison of primary standard gas mixtures: gravimetric production of carbon monoxide in nitrogen (3 μmol/mol)

    Science.gov (United States)

    Konopelko, L. A.; Kustikov, Y. A.; Kolobova, A. V.; Pankratov, V. V.; Pankov, A. A.; Efremova, O. V.; Augusto, Cristiane R.; Fioravante, Andreia L.; Ribeiro, Claudia C.; Teixeira, Denise C. G. S.; Elias, Elizandra C. S.; Oudwater, Rutger J.; Fagundes, Fátima A.; Silva, Marceli C.

    2016-01-01

    COOMET.QM-S3 is a supplementary comparison of primary standard gas mixtures—'Carbon monoxide in Nitrogen (3 μmol/mol)'. This is a bilateral comparison between VNIIM and INMETRO and it was conducted in 2013. Carbon monoxide is a toxic gas and in concentrations higher than 3-5 μmol/mol it is hazardous to human health. Therefore, it is important for NMIs to have the capability of an accurate carbon monoxide measurements. This comparison has shown that primary standard gas mixtures of carbon monoxide in nitrogen on the level of 3 μmol/mol, prepared in VNIIM and Inmetro, do not agree—the pair-wise degree of equivalence D (0.77%) is higher than the appropriate expanded uncertainty U(D) (0.29%). Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  4. Irradiation effect on the reaction of mixture of carbon monoxide and hydrogen, (3)

    International Nuclear Information System (INIS)

    A series of our studies on radiation chemical reaction of CO and H2 mixture indicated that several organic compounds were produced by electron beam irradiation and the amounts of the products increased with increasing pressure and also increased when the irradiation was carried out under circulation. The present study was carried out in an attempt to investigate whether the amounts of the products increase when the mixture is irradiated under circulation at elevated pressure. For this purpose, a reaction apparatus, which can irradiated the mixture up to 10,000 Torr under circulation, was built and the experiments were carried out on the amounts of products as functions of pressure, irradiation time, gas composition, temperature and dose rate. G values of most compounds were found to increased with increasing pressure under circulation. Among the products, the reaction conditions giving high yield of acetaldehyde were studied in detail, since this compound is considered to be one of the most important intermediate compounds in C1 chemistry. The maximum G value of acetaldehyde was 2.9 which was obtained at 8,000 Torr, 55 CO mol%, 2 x 1019 eV.g-1.sec-1, 1.3 x 1020 eV.g-1 and 22 0C. The selectivity favored this compounds in all organic compounds was 57 mol% at the conversion rate of 0.8 %. In order to elucidate the reaction paths of formation and disappearance of acetaldehyde, the amounts of products were determined for the mixture with or without the presence of small amounts of acetadehyde. The results indicate that acetaldehyde formed by irradiation from

  5. Crystallization of -type hexagonal ferrites from mechanically activated mixtures of barium carbonate and goethite

    Indian Academy of Sciences (India)

    J Temuujin; M Aoyama; M Senna; T Masuko; C Ando; H Kishi; A Minjigmaa

    2006-10-01

    -type hexagonal ferrite precursor was prepared by a soft mechanochemical treatment of BaCO3 and -FeOOH mixtures. The effect of milling on its structure and thermal behaviour was examined by XRD, SEM and FTIR. Well crystallized -type hexagonal ferrite was formed from just 1 h milled precursors at 800°C. The beneficial effect of milling was explained in terms of increased homogeneity with simultaneous hetero bridging bond formation between powder constituents.

  6. Assessment of uranium tetrafluoride dissolution in the lung by in vivo and in vitro methods

    International Nuclear Information System (INIS)

    The data acquired over the past twenty years concerning the solubility of uranium tetrafluoride (UF4) are contradictory. To check the validity of this compound's W classification by the ICRP, we investigated its in vivo dissolution in rats and baboons and compared it to the in vitro dissolution obtained either with alveolar macrophages in culture or with a serum simulant fluid. We studied daily urinary excretion of uranium in rats and baboons and U tissue distribution in rats after inhalation of raw UF4 powder or intratracheal instillation of a UF4 particle suspension. Alveolar macrophages from 4 rats and 2 baboons were tested for their ability to dissolve UF4. Since UF4 dissolution in the lung may be influenced by oxidation to the very soluble form UO2F2, we performed in vitro dissolution with a serum simulant fluid bubbled with either pure oxygen or argon. There was good agreement between the in vivo and in vitro results for both rats and baboons. Our results support the view that dissolution of UF4 in the lung is fast, and that this compound is more soluble than expected. (author)

  7. The influence of shape resonance phenomena on the valence shell photoionization dynamics of silicon tetrafluoride

    International Nuclear Information System (INIS)

    The complete valence shell photoelectron spectrum of silicon tetrafluoride has been studied both experimentally and theoretically. Photoelectron angular distributions and branching ratios have been measured in the photon energy range 17-120 eV, using synchrotron radiation, and compared with previous theoretical predictions. The spectra demonstrate that shape resonance phenomena affect the photoionization dynamics of the outer valence shell orbitals, and the predicted shape resonance in the a1 channel, close to threshold, has been confirmed experimentally. At higher energies, the effects of the e and t2 symmetry shape resonances have been observed, for the first time, in the photoelectron asymmetry parameters. Partial photoionization cross sections have been derived by combining the experimental branching ratios with the total ion yield curve and normalizing the results to the absolute photoabsorption cross section. The partial cross sections so obtained have been compared with theoretical curves reported in two earlier studies. The vertical ionization energies and spectroscopic factors for the entire valence shell photoelectron spectrum have been computed using the third-order algebraic-diagrammatic construction approximation scheme for the one-particle Green function. (author)

  8. Environmental impacts of options for disposal of depleted uranium tetrafluoride (UF4)

    International Nuclear Information System (INIS)

    The U.S. Department of Energy (DOE) evaluated options for managing its depleted uranium hexafluoride (UF6) inventory in the Programmatic Environmental Impact Statement for the Long-Term Management and Use of Depleted Uranium Hexafluoride (PEIS) of April 1999. Along with the impacts from other management options, the PEIS discussed the environmental impacts from the disposal of depleted uranium oxide, which could result from the chemical conversion of depleted UF6. It has been suggested that the depleted UF6 could also be converted to uranium tetrafluoride (UF4) and disposed of. This report considers the potential environmental impacts from the disposal of DOE's depleted UF6 inventory after its conversion to UF4. The impacts were evaluated for the same three disposal facility options that were considered in the PEIS for uranium oxide: shallow earthen structures, belowground vaults, and mines. They were evaluated for a dry environmental setting representative of the western United States. To facilitate comparisons and future decision making, the depleted UF4 disposal analyses performed and the results presented in this report are at the same level of detail as that in the PEIS

  9. Dry uranium tetrafluoride process preparation using the uranium hexafluoride reconversion process effluents

    International Nuclear Information System (INIS)

    It is a well known fact that the use of uranium tetrafluoride allows flexibility in the production of uranium suicide and uranium oxide fuel. To its obtention there are two conventional routes, the one which reduces uranium from the UF6 hydrolysis solution with stannous chloride, and the hydro fluorination of a solid uranium dioxide. In this work we are introducing a third and a dry way route, mainly utilized to the recovery of uranium from the liquid effluents generated in the uranium hexafluoride reconversion process, at IPEN/CNEN-SP. Working in the liquid phase, this route comprises the recuperation of ammonium fluoride by NH4HF2 precipitation. Working with the solid residues, the crystallized bifluoride is added to the solid UO2, which comes from the U mini plates recovery, also to its conversion in a solid state reaction, to obtain UF4. That returns to the process of metallic uranium production unity to the U3Si2 obtention. This fuel is considered in IPEN CNEN/SP as the high density fuel phase for IEA-R1m reactor, which will replace the former low density U3Si2-Al fuel. (author)

  10. Functional evaluation of rat hearts transplanted after preservation in a high-pressure gaseous mixture of carbon monoxide and oxygen.

    Science.gov (United States)

    Hatayama, Naoyuki; Inubushi, Masayuki; Naito, Munekazu; Hirai, Shuichi; Jin, Yong-Nan; Tsuji, Atsushi B; Seki, Kunihiro; Itoh, Masahiro; Saga, Tsuneo; Li, Xiao-Kang

    2016-01-01

    We recently succeeded in resuscitating an extracted rat heart following 24-48 hours of preservation in a high-pressure gaseous mixture of carbon monoxide (CO) and oxygen (O2). This study aimed to examine the function of rat hearts transplanted after being preserved in the high-pressure CO and O2 gas mixture. The hearts of donor rats were preserved in a chamber filled with CO and O2 under high pressure for 24 h (CO24h) or 48 h at 4 °C. For the positive control (PC) group, hearts immediately extracted from donor rats were used for transplantation. The preserved hearts were transplanted into recipient rats by heterotopic cervical heart transplantation. CO toxicity does not affect the grafts or the recipients. Light microscopy and [(18)F]-fluorodeoxyglucose positron emission tomography revealed that there were no significant differences in the size of the myocardial infarction or apoptosis of myocardial cells in post-transplant hearts between the PC and CO24h groups. Furthermore, at 100 days after the transplantation, the heart rate, weight and histological staining of the post-transplanted hearts did not differ significantly between the PC and CO24h groups. These results indicate that the function of rat hearts is well preserved after 24 hours of high-pressure preservation in a CO and O2 gas mixture. Therefore, high-pressure preservation in a gas mixture can be a useful method for organ preservation. PMID:27562456

  11. Simulation of Hydrate Dissociation Equilibrium for Carbon dioxide–methane Mixture

    OpenAIRE

    Huong, V. T.; Mukhtar, H; Murugesan, T.

    2008-01-01

    The objective of the present studyis to explore the potential of removing carbon dioxide from natural gas byforming gas hydrate. The parameters governing the dissociation of gas hydrate have been identified. An attempt has been made to select the favorable operating conditions for methane-carbon dioxide separation through the dissociation of gas hydrate. The K-factor method along with Peng-Robinson equation of state are employed in ICON simulator to obtain hydrate dissociation temperature and...

  12. Ebulliometric determination and prediction of (vapor + liquid) equilibria for binary and ternary mixtures containing alcohols (C1-C4) and dimethyl carbonate

    International Nuclear Information System (INIS)

    Highlights: → The VLE behavior of systems containing dimethyl carbonate (DMC) was investigated. → VLE data for ternary and binary mixtures containing alcohol and DMC were measured. → Several activity coefficient models were used for data reduction or prediction. → Valley line, i.e., distillation boundary, was observed for the ternary mixture. → Residue curves were calculated to investigate composition profile for distillation. - Abstract: (Vapor + liquid) equilibrium (VLE) data for a ternary mixture, namely {methanol + propan-1-ol + dimethyl carbonate (DMC)}, and four binary mixtures, namely an {alcohol (C3 or C4) + DMC}, containing the binary constituent mixtures of the ternary mixture, were measured at p = (40.00 to 93.32) kPa using a modified Swietoslawski-type ebulliometer. The experimental data for the binary systems were correlated using the Wilson model. The Wilson model was also applied to the ternary system to predict the VLE behavior using parameters from the binary mixtures. The modified UNIFAC (Dortmund) model was also tested for the predictions of the VLE behavior of the binary and ternary mixtures. In addition, the experimental VLE data for the ternary and constituent binary mixtures were correlated using the extended Redlich-Kister (ERK) model, which can completely represent the azeotropic points. For the ternary system, a comparison of the experimental and the predicted or correlated boiling points obtained using the Wilson and ERK models showed that the ERK model is more accurate. The valley line, i.e., the curve which divides the patterns of vapor-liquid tie lines, was found in the (methanol + propan-1-ol + DMC) system. This valley line could be represented by the ERK model. Finally, the composition profile for simple distillation of this ternary mixture was obtained by analysis of the residue curves from the estimated Wilson parameters of the constituent binary mixtures.

  13. Carbon-coated hexagonal magnetite nanoflakes production by spray CVD of alcohols in mixture with water

    International Nuclear Information System (INIS)

    In this study, we report a successful technique for synthesizing magnetite hexagonal nanoflakes coated with carbon layers using spray thermal decomposition, which is a reproducible method that is easy to scale up. We investigated the effects of mixing different volumes of deionized (DI) water with alcohol on the population and quality of single-crystalline Fe3O4 hexagonal nanoflakes. Methanol and ethanol were used as the carbon and oxygen source, while ferrocene was mainly used as the Fe source. To obtain a large quantity of hexagonal structures, a strongly oxidative atmosphere was required. The DI water was used to enhance the oxidative environment during the reaction and was an important component for obtaining well-shaped hexagonal magnetite crystalline nanoflakes. The use of alcohols, water and the spray chemical vapor deposition (CVD) method make this procedure easy to use. In addition, this method provides a one-step process for synthesizing carbon-coated hexagonal Fe3O4 nanocrystals. (paper)

  14. Binary Adsorption Equilibrium of Benzene—Water Vapor Mixtures on Activated Carbon

    Institute of Scientific and Technical Information of China (English)

    GAOHuasheng; YEYunchun; 等

    2002-01-01

    Adsorption equilibrium isotherms of benzene in the concentration range of 500-4000mg·m-3 on two commercial activated carbons were obtained using long-column method under 30℃ and different humidity conditions. Results show that the benzene and water vapors have depression effects upon the adsorption of each other and that the unfavorable effect of water vapor resembles its single-component isotherm on activated carbon.A competitive adsorption model was proposed to explore the depression mechanisms of the non-ideal,non-similar binary adsorption systems.A modified polanyi-Dubinin equation was set up to correlate the binary adsorption equilibrium and to calculte the isotherms of benzene on activated carbon in presence of water vapor with considerable precision.

  15. Kinetics of methane hydrate replacement with carbon dioxide and nitrogen gas mixture using in situ NMR spectroscopy.

    Science.gov (United States)

    Cha, Minjun; Shin, Kyuchul; Lee, Huen; Moudrakovski, Igor L; Ripmeester, John A; Seo, Yutaek

    2015-02-01

    In this study, the kinetics of methane replacement with carbon dioxide and nitrogen gas in methane gas hydrate prepared in porous silica gel matrices has been studied by in situ (1)H and (13)C NMR spectroscopy. The replacement process was monitored by in situ (1)H NMR spectra, where about 42 mol % of the methane in the hydrate cages was replaced in 65 h. Large amounts of free water were not observed during the replacement process, indicating a spontaneous replacement reaction upon exposing methane hydrate to carbon dioxide and nitrogen gas mixture. From in situ (13)C NMR spectra, we confirmed that the replacement ratio was slightly higher in small cages, but due to the composition of structure I hydrate, the amount of methane evolved from the large cages was larger than that of the small cages. Compositional analysis of vapor and hydrate phases was also carried out after the replacement reaction ceased. Notably, the composition changes in hydrate phases after the replacement reaction would be affected by the difference in the chemical potential between the vapor phase and hydrate surface rather than a pore size effect. These results suggest that the replacement technique provides methane recovery as well as stabilization of the resulting carbon dioxide hydrate phase without melting. PMID:25565018

  16. Phase Equilibria of Three Binary Mixtures: Methanethiol + Methane, Methanethiol + Nitrogen, and Methanethiol + Carbon Dioxide

    DEFF Research Database (Denmark)

    Awan, Javeed; Tsivintzelis, Ioannis; Coquelet, Christophe; Kontogeorgis, Georgios

    2012-01-01

    New vapor–liquid equilibrium (VLE) data for methanethiol (MM) + methane (CH4), methanethiol (MM) + nitrogen (N2), and methanethiol (MM) + carbon dioxide (CO2) is reported for temperatures of (304, 334, and 364) K in the pressure range (1 to 8) MPa. A “static–analytic” method was used for performi...

  17. Regularities of thermochemical characteristics of 1-1, 2-1, 3-1 electrolyte solutions in dimethyl sulfoxide-water and propylene carbonate water mixtures

    International Nuclear Information System (INIS)

    In an air-tight tilting calorimeter with an isothermal casing enthalpies of praseodymium chloride solution in water, dimethyl sulfoxide (DMSO) - water mixtures, contaning 3.86 and 18.53 mol.% DMSO, and propylene carbonate (PC) - water mixtures, containing 1.85 and 3.23 mol.% PC are measured. The enthalpies of praseodymium chloride solution in the given mixtures in case of infinite solution dilution are determined. Solvation enthalpies of praseodymium and neodymium chlorides, as well as alkali earth metal and magnesium chlorides in water and DMSO - water and PC - water mixtures are calculated. Regularities in thermochemical characteristics of solutions of the given salts in DMSO - water and PC - water mixtures are discussed

  18. Oil Spill Adsorption Capacity of Activated Carbon Tablets from Corncobs in Simulated Oil-Water Mixture

    Directory of Open Access Journals (Sweden)

    Rhonalyn V. Maulion

    2015-12-01

    Full Text Available Oil spill in bodies of water is one of severe environmental problems that is facing all over the country and in the world. Since oil is an integral part of the economy, increasing trend for its demand and transport of has led to a great treat in the surface water. One of the promising techniques in the removal of the oil spills in water bodies is adsorption using activated carbon form waste material such as corn cobs. The purpose of this study is to determine the adsorption capacity of activated carbon tablets derived from corncobs in the removal of oil. The properties of activated carbon produced have a pH of 7.0, bulk density of 0.26 g//cm3 , average pore size of 45nm, particle size of 18% at 60 mesh and 39% at 80 mesh, iodine number of 1370 mg/g and surface area of 1205 g/m2. The amount of bentonite clay as binder (15%,20%,30%, number of ACT (1,2,3 and time of contact(30,60,90 mins has been varied to determine the optimum condition where the activated carbon will have the best adsorption capacity in the removal of oil. Results showed that at 15% binder, 60 mins contact time and 3 tablets of activated carbon is the optimum condition which give a percentage adsorption of 22.82% of oil. Experimental data also showed that a Langmuir isotherm was the best fit isotherm for adsorption of ACT.

  19. Origin and evolution of paramagnetic states in mixtures of ZnO and carbon nanoparticles during intensive mechanical treatment

    International Nuclear Information System (INIS)

    In this study, the microstructural evolution and reaction processes in the mixture of ZnO + xC nanoparticles during prolonged high-energy mechanical activation were explored. The formation of paramagnetic centers has been identified. It was observed that the evolution of various paramagnetic defects reveals several macroscopic flow processes that take place in the system. Some of these processes are the destruction of primary durable nanoparticle ZnO aggregates, the crushing of individual nanoparticles (250–14 nm), the development of accumulative thermal processes in the sample, the interaction of carbon atoms with oxygen from the treatment chamber and from the surface of the ZnO nanoparticles, the formation of reducing atmosphere in the grinding chamber, and the occurrence of the forming conditions of the phase transition ZnOW → ZnOS on the surface layers of ZnOW nanoparticles

  20. Protective effect of different tetrafluorides on erosion of pellicle-free and pellicle-covered enamel and dentine

    OpenAIRE

    Wiegand, Annette; Meier, Werner; E. Sutter; Magalhães, Ana C.; Becker, Klaus; Roos, Malgorzata; Attin, Thomas

    2008-01-01

    The aim was to analyze the protective effects of titanium, zirconium and hafnium tetrafluorides on erosion of pellicle-free and pellicle-covered enamel and dentine in vitro. Eight groups of 20 specimens each of bovine enamel and bovine dentine were prepared. Half the specimens in each group were immersed in human saliva for 2 h for pellicle formation. Specimens were then left untreated (controls) or were treated for 120 s with TiF(4), ZrF(4) or HfF(4) solutions (0.4 or 1%) or 1.25% AmF/NaF ge...

  1. Heated uranium tetrafluoride target system to release non-rare gas fission products for the TRISTAN isotope separator

    International Nuclear Information System (INIS)

    Off-line experiments indicated that fluorides of As, Se, Br, Kr, Zr, Nb, Mo, Tc, Ru, Sb, Te, I and Xe could be volatilized, but except for Br, Kr, I and Xe, none of these elements were observed after mass separation in the on-line experiments. The results of the on-line experiments indicated a very low level of hydride contamination at ambient temperature and consequently, uranium tetrafluoride replaced uranyl stearate as the primary gaseous fission product target. Possible reasons for the failure of the heated target system to yield non-rare gas activities are discussed and suggestions for designing a new heated target system are presented

  2. Oil Spill Adsorption Capacity of Activated Carbon Tablets from Corncobs in Simulated Oil-Water Mixture

    OpenAIRE

    Rhonalyn V. Maulion; Sheila Adarlo Abacan; Gerald Garces Allorde; Ma. Cherrielyne Silda Umali

    2015-01-01

    Oil spill in bodies of water is one of severe environmental problems that is facing all over the country and in the world. Since oil is an integral part of the economy, increasing trend for its demand and transport of has led to a great treat in the surface water. One of the promising techniques in the removal of the oil spills in water bodies is adsorption using activated carbon form waste material such as corn cobs. The purpose of this study is to determine the adsorption capaci...

  3. Methods of analysis for complex organic aerosol mixtures from urban emission sources of particulate carbon

    International Nuclear Information System (INIS)

    Organic aerosols comprise approximately 30% by mass of the total fine particulate matter present in urban atmospheres. The chemical composition of such aerosols is complex and reflects input from multiple sources of primary emissions to the atmosphere, as well as from secondary production of carbonaceous aerosol species via photochemical reactions. To identify discrete sources of fine carbonaceous particles in urban atmospheres, analytical methods must reconcile both bulk chemical and molecular properties of the total carbonaceous aerosol fraction. This paper presents an overview of the analytical protocol developed and used in a study of the major sources of fine carbon particles emitted to an urban atmosphere. 23 refs., 1 fig., 2 tabs

  4. One-dimensional turbulence model simulations of autoignition of hydrogen/carbon monoxide fuel mixtures in a turbulent jet

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Kamlesh G.; Echekki, Tarek [Department of Mechanical and Aerospace Engineering, North Carolina State University, NC (United States)

    2011-02-15

    The autoignition of hydrogen/carbon monoxide in a turbulent jet with preheated co-flow air is studied using the one-dimensional turbulence (ODT) model. The simulations are performed at atmospheric pressure based on varying the jet Reynolds number and the oxidizer preheat temperature for two compositions corresponding to varying the ratios of H{sub 2} and CO in the fuel stream. Moreover, simulations for homogeneous autoignition are implemented for similar mixture conditions for comparison with the turbulent jet results. The results identify the key effects of differential diffusion and turbulence on the onset and eventual progress of autoignition in the turbulent jets. The differential diffusion of hydrogen fuels results in a reduction of the ignition delay relative to similar conditions of homogeneous autoignition. Turbulence may play an important role in delaying ignition at high-turbulence conditions, a process countered by the differential diffusion of hydrogen relative to carbon monoxide; however, when ignition is established, turbulence enhances the overall rates of combustion of the non-premixed flame downstream of the ignition point. (author)

  5. Sorption of a mixture of phenols in aqueous solution with activated carbon; Sorcion de una mezcla de fenoles en solucion acuosa con carbon activado

    Energy Technology Data Exchange (ETDEWEB)

    Mejia M, D.; Lopez M, B.E.; Iturbe G, J.L. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    The main objective of this work is the sorption of an aqueous mixture of phenol-4 chloro phenol of different concentrations in a molar relationship 1:1 in activated carbon of mineral origin of different nets (10, 20 and 30) and to diminish with it its presence in water. The experimental results show that the removal capacity depends so much of the surface properties of the sorbent like of the physical and chemical properties of the sorbate. In all the cases it was observed that in the aqueous systems of low concentration the 4-chloro phenol are removed in an approximate proportion of 1.2-4 times greater to than phenol, however to concentrations but high both they are removed approximately in the same proportion. (Author)

  6. Transport coefficients for carbon, hydrogen, and the organic mixture C2H3

    International Nuclear Information System (INIS)

    Electrical and thermal transport coefficients are calculated for amorphous elemental carbon and hydrogen, using the best available systematic theoretical methods. The density range considered is 10-3g/cm3 less than or equal to rho less than or equal to 106g/cm3 for carbon, and 10-4g/cm3 less than or equal to rho less than or equal to 105g/cm3 for hydrogen. The temperature range considered is 10-2eV less than or equal to kT less than or equal to 104eV. Calculational methods include relativistic partial-wave analysis of the extended Ziman theory, and nonrelativistic plane-wave analysis (Born approximation) of the original Ziman theory. Physical models include relativistic Dirac-Fock-Slater and nonrelativistic Thomas-Fermi-Dirac electron-ion potentials, and one-component-plasma ion-ion structure factors. A mixing algorithm is used to obtain approximate transport coefficients for the atomic ratio C2H3. 10 refs., 31 figs

  7. Characteristics of autoignited laminar lifted flames in heated coflow jets of carbon monoxide/hydrogen mixtures

    KAUST Repository

    Choi, Byungchul

    2012-06-01

    The characteristics of autoignited lifted flames in laminar jets of carbon monoxide/hydrogen fuels have been investigated experimentally in heated coflow air. In result, as the jet velocity increased, the blowoff was directly occurred from the nozzle-attached flame without experiencing a stabilized lifted flame, in the non-autoignited regime. In the autoignited regime, the autoignited lifted flame of carbon monoxide diluted by nitrogen was affected by the water vapor content in the compressed air oxidizer, as evidenced by the variation of the ignition delay time estimated by numerical calculation. In particular, in the autoignition regime at low temperatures with added hydrogen, the liftoff height of the autoignited lifted flames decreased and then increased as the jet velocity increased. Based on the mechanism in which the autoignited laminar lifted flame is stabilized by ignition delay time, the liftoff height can be influenced not only by the heat loss, but also by the preferential diffusion between momentum and mass diffusion in fuel jets during the autoignition process. © 2012 The Korean Society of Mechanical Engineers.

  8. Characteristics of autoignited laminar lifted flames in heated coflow jets of carbon monoxide/hydrogen mixtures

    International Nuclear Information System (INIS)

    The characteristics of autoignited lifted flames in laminar jets of carbon monoxide/hydrogen fuels have been investigated experimentally in heated coflow air. In result, as the jet velocity increased, the blowoff was directly occurred from the nozzle attached flame without experiencing a stabilized lifted flame, in the non autoignited regime. In the autoignited regime, the autoignited lifted flame of carbon monoxide diluted by nitrogen was affected by the water vapor content in the compressed air oxidizer, as evidenced by the variation of the ignition delay time estimated by numerical calculation. In particular, in the autoignition regime at low temperatures with added hydrogen, the liftoff height of the autoignited lifted flames decreased and then increased as the jet velocity increased. Based on the mechanism in which the autoignited laminar lifted flame is stabilized by ignition delay time, the liftoff height can be influenced not only by the heat loss, but also by the preferential diffusion between momentum and mass diffusion in fuel jets during the autoignition process

  9. High-Pressure Phase Behavior of Polycaprolactone, Carbon Dioxide, and Dichloromethane Ternary Mixture Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gwon, JungMin; Kim, Hwayong [Seoul National University, Seoul (Korea, Republic of); Shin, Hun Yong [Seoul National University of Science and Technology, Seoul (Korea, Republic of); Kim, Soo Hyun [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    2015-04-15

    The high-pressure phase behavior of a polycaprolactone (Mw=56,145 g/mol, polydispersity 1.2), dichloromethane, and carbon dioxide ternary system was measured using a variable-volume view cell. The experimental temperatures and pressures ranged from 313.15 K to 353.15 K and up to 300 bar as functions of the CO{sub 2}/dichloromethane mass ratio and temperature, at poly(D-lactic acid) weight fractions of 1.0, 2.0, and 3.0%. The correlation results were obtained from the hybrid equation of state (Peng-Robinson equation of state + SAFT equation of state) for the CO{sub 2}-polymer system using the van der Waals one-fluid mixing rule. The three binary interaction parameters were optimized by the simplex method algorithm.

  10. Improvement of the relaxation time and the order parameter of nematic liquid crystal using a hybrid alignment mixture of carbon nanotube and polyimide

    International Nuclear Information System (INIS)

    We examined the electrooptical properties of a nematic liquid crystal (LC) sample whose substrates were coated with a mixture of carbon nanotube (CNT) and polyimide (PI). The relaxation time of the sample coated with 1.5 wt. % CNT mixture was about 35% reduced compared to the pure polyimide sample. The elastic constant and the order parameter of the CNT-mixture sample were increased and the fast relaxation of LC could be approximated to the mean-field theory. We found the CNT-mixed polyimide formed more smooth surface than the pure PI from atomic force microscopy images, indicating the increased order parameter is related to the smooth surface topology of the CNT-polyimide mixture

  11. Improvement of the relaxation time and the order parameter of nematic liquid crystal using a hybrid alignment mixture of carbon nanotube and polyimide

    Science.gov (United States)

    Lee, Hyojin; Yang, Seungbin; Lee, Ji-Hoon; Soo Park, Young

    2014-05-01

    We examined the electrooptical properties of a nematic liquid crystal (LC) sample whose substrates were coated with a mixture of carbon nanotube (CNT) and polyimide (PI). The relaxation time of the sample coated with 1.5 wt. % CNT mixture was about 35% reduced compared to the pure polyimide sample. The elastic constant and the order parameter of the CNT-mixture sample were increased and the fast relaxation of LC could be approximated to the mean-field theory. We found the CNT-mixed polyimide formed more smooth surface than the pure PI from atomic force microscopy images, indicating the increased order parameter is related to the smooth surface topology of the CNT-polyimide mixture.

  12. Improvement of the relaxation time and the order parameter of nematic liquid crystal using a hybrid alignment mixture of carbon nanotube and polyimide

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyojin; Yang, Seungbin; Lee, Ji-Hoon, E-mail: jihoonlee@jbnu.ac.kr [Advanced Electronics and Information Research Center, Division of Electronic Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Soo Park, Young, E-mail: irony@kctech.re.kr [Department of Polymer-Nano Science and Technology, Chonbuk National University, Jeonju, Jeonbuk, 561-756 (Korea, Republic of); Korea Institute of Carbon Convergence Technology, Banryong-ro, Jeonju, Jeonbuk 561-844 (Korea, Republic of)

    2014-05-12

    We examined the electrooptical properties of a nematic liquid crystal (LC) sample whose substrates were coated with a mixture of carbon nanotube (CNT) and polyimide (PI). The relaxation time of the sample coated with 1.5 wt. % CNT mixture was about 35% reduced compared to the pure polyimide sample. The elastic constant and the order parameter of the CNT-mixture sample were increased and the fast relaxation of LC could be approximated to the mean-field theory. We found the CNT-mixed polyimide formed more smooth surface than the pure PI from atomic force microscopy images, indicating the increased order parameter is related to the smooth surface topology of the CNT-polyimide mixture.

  13. Investigation of Ternary Mixtures Containing 1-Ethyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)azanide, Ethylene Carbonate and Lithium Bis(trifluoromethanesulfonyl)azanide

    Science.gov (United States)

    Hofmann, Andreas; Migeot, Matthias; Arens, Lukas; Hanemann, Thomas

    2016-01-01

    Temperature-dependent viscosity, conductivity and density data of ternary mixtures containing 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)azanide (EMIM-TFSA), ethylene carbonate (EC), and lithium bis(trifluoromethanesulfonyl)azanide (Li-TFSA) were determined at atmospheric pressure in the temperature range of 20 to 80 °C. Differential scanning calorimetry (DSC) measurements were performed to characterize phase conditions of the mixtures in a temperature range of −120 to +100 °C. The viscosity data were fitted according to the Vogel-Fulcher-Tammann-Hesse (VFTH) equation and analyzed with the help of the fractional Walden rule. In this study, fundamental physicochemical data about the mixtures are provided and discussed as a basis for structure-property relationship calculations and for potential use of those mixtures as electrolytes for various applications. PMID:27153066

  14. Effect of carbon type (graphite, CFs and diamond) on the hydrogen desorption of Mg–C powder mixtures under microwave irradiation

    International Nuclear Information System (INIS)

    Highlights: • MgH2 + x wt% C milled mixtures desorbed hydrogen rapidly under micro waves exposition. • Carbon fibers are effective to reduce the desorption time. • Almost full desorption can be reached in 10 s. - Abstract: Binary MgH2–x wt% C mixtures (x = 0, 2, 5 and 10 wt% for carbon fibers (CFs), 10 wt% for graphite (G) and diamond (D)) were prepared by hand mixing and by ball milling (5 h) for MgH2–10 wt% CFs. The aims of the work were: – to investigate the dehydriding reaction of MgH2 catalyzed by carbon under microwave irradiation; – to assess the effect of presence of different carbon type and content on the desorption reaction; – to evaluate the influence microwave power on the rate of hydrogen release; to study the influence of milling process on the dehydrogenation time. The amount of hydride and Mg phases (e.g. hydrogen content) was estimated from XRD pattern matching (Eva and Fullprof). The morphology of the powders and the particle size distribution were observed by Scanning Electron Microscopy (SEM) and laser granulometry respectively. Carbon distribution in the MgH2 matrix was investigated by electron probe microanalyses. The different carbon type transfer the heat, generated from absorbed microwave irradiation, to the MgH2 matrix which induces the hydrogen release. It was found that the dehydrogenation rate and time were enhanced with rising carbon content, microwave power and with milling time. For the MgH2–10 wt% CFs mixtures, under 1500 W of microwave, more than 90% of conversion MgH2 to Mg phases was obtained after 20 s for hand mixing mixture and after only 10 s for 5 h ball milled one

  15. Effect of carbon type (graphite, CFs and diamond) on the hydrogen desorption of Mg–C powder mixtures under microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Awad, A.S., E-mail: awad@icmcb-bordeaux.cnrs.fr [Université de Bordeaux, ICMCB, 87 Avenue du Dr Schweitzer, F-33608 Pessac (France); LCPM, Université Libanaise, Faculté des Sciences 2, 90656 Jdeidet El Matn (Lebanon); Tayeh, T. [Université de Bordeaux, ICMCB, 87 Avenue du Dr Schweitzer, F-33608 Pessac (France); LCPM, Université Libanaise, Faculté des Sciences 2, 90656 Jdeidet El Matn (Lebanon); Nakhl, M.; Zakhour, M. [LCPM, Université Libanaise, Faculté des Sciences 2, 90656 Jdeidet El Matn (Lebanon); Ourane, B.; Le Troëdec, M.; Bobet, J.-L. [Université de Bordeaux, ICMCB, 87 Avenue du Dr Schweitzer, F-33608 Pessac (France)

    2014-09-01

    Highlights: • MgH{sub 2} + x wt% C milled mixtures desorbed hydrogen rapidly under micro waves exposition. • Carbon fibers are effective to reduce the desorption time. • Almost full desorption can be reached in 10 s. - Abstract: Binary MgH{sub 2}–x wt% C mixtures (x = 0, 2, 5 and 10 wt% for carbon fibers (CFs), 10 wt% for graphite (G) and diamond (D)) were prepared by hand mixing and by ball milling (5 h) for MgH{sub 2}–10 wt% CFs. The aims of the work were: – to investigate the dehydriding reaction of MgH{sub 2} catalyzed by carbon under microwave irradiation; – to assess the effect of presence of different carbon type and content on the desorption reaction; – to evaluate the influence microwave power on the rate of hydrogen release; to study the influence of milling process on the dehydrogenation time. The amount of hydride and Mg phases (e.g. hydrogen content) was estimated from XRD pattern matching (Eva and Fullprof). The morphology of the powders and the particle size distribution were observed by Scanning Electron Microscopy (SEM) and laser granulometry respectively. Carbon distribution in the MgH{sub 2} matrix was investigated by electron probe microanalyses. The different carbon type transfer the heat, generated from absorbed microwave irradiation, to the MgH{sub 2} matrix which induces the hydrogen release. It was found that the dehydrogenation rate and time were enhanced with rising carbon content, microwave power and with milling time. For the MgH{sub 2}–10 wt% CFs mixtures, under 1500 W of microwave, more than 90% of conversion MgH{sub 2} to Mg phases was obtained after 20 s for hand mixing mixture and after only 10 s for 5 h ball milled one.

  16. Understanding adsorption of CO2, N2, CH4 and their mixtures in functionalized carbon nanopipe arrays.

    Science.gov (United States)

    Halder, Prosun; Maurya, Manish; Jain, Surendra K; Singh, Jayant K

    2016-05-18

    The selective adsorption behaviours of carbon dioxide, methane and nitrogen on bundles of functionalized CMK-5 are investigated at 303 K using grand-canonical Monte Carlo simulations. Functional groups (-OH, -COOH) cause a significant enhancement in CO2 uptake (up to 19.5% at a pressure of 38.13 bar for -COOH). On the other hand, the adsorption amount of methane decreases with respect to bare CMK-5 by ∼13% (at 38.13 bar) upon functionalization. Furthermore, functionalized CMK-5 with different pore sizes (4 nm, 6 nm, 8 nm) and inter-tube distances (d = 0 to 1.5 nm) are used to investigate the adsorption behaviour of flue gases. While the pore diameter is seen to reduce the isosteric heat of adsorption, the inter-tube distance of 0.25 nm shows the highest uptake of CO2 at p ≤ 18 bar, followed by 0.5 nm for the pressure range of 18 30 bar, d = 1.0 nm shows the maximum uptake. For methane and nitrogen, the maximum adsorption is obtained at d = 0.25 nm in the studied pressure range. The selective adsorption of CO2 in binary mixtures is investigated using ideal adsorption solution theory. CO2-N2 selectivity is found to increase significantly by surface functionalization of CMK-5 compared to pure CMK-5. The maximum selectivity of CO2-CH4 using -COOH functionalized CMK-5 is found to be ∼10 for an equimolar CO2-CH4 mixture at a pressure of 38.13 bar. PMID:27158697

  17. Groundwater calculations for depleted uranium disposed of as uranium tetrafluoride (UF4)

    International Nuclear Information System (INIS)

    This report discusses calculations performed to estimate the impacts on groundwater from the long-term disposal of depleted uranium in the form of uranium tetrafluoride (UF4) in a trench, vault, and mined cavity. The calculations were done for a deep groundwater system, typical of conditions in the western United States. They were performed for two initial inventories of UF4: 500,000 and 630,000 metric tons. Disposal was in either 30- or 50-gal drums. All of the contaminant and radioactivity concentrations at the water table are predicted to be very low, even for a fairly mobile compound. In general, concentrations after 1,000 years at the water table would be about an order of magnitude greater for disposal in a deep mine than for disposal in a trench or vault. The largest activity concentration at the water table after 1,000 years would be derived from a failed mine that releases a fairly mobile and very soluble uranium complex; it would be about 8.6 x 10-6 pCi/L for 500,000 metric tons of UF4 disposed of in 30-gal drums. The smallest activity concentrations at the water table after 1,000 years would, in general, be derived from a failed trench (1.2 x 10-9 pCi/L), if the contaminant reached the water table as schoepite. Although all the activity concentrations at the water table after 1,000 years are predicted to be small, maximum activity concentrations could still be large, even after dilution. Maximum activity concentrations of uranium would exceed 900 pCi/L for a failed disposal facility if a very soluble and mobile uranium complex formed. If the solubility of the uranium compound was small (2.4 x 10-3 g/L), the resulting activity concentrations would be small, less than 2.5 pCi/L. The estimated time for these maximum concentrations would range from 65,000 to 2,000,000 years

  18. Gaseous product mixture from Fischer-Tropsch synthesis as an efficient carbon feedstock for low temperature CVD growth of carbon nanotube carpets.

    Science.gov (United States)

    Almkhelfe, Haider; Carpena-Núñez, Jennifer; Back, Tyson C; Amama, Placidus B

    2016-07-21

    Low-temperature chemical vapor deposition (CVD) growth of carbon nanotube (CNT) carpets from Fe and Fe-Cu catalysts using a gaseous product mixture from Fischer-Tropsch synthesis (FTS-GP) as a superior carbon feedstock is demonstrated. This growth approach addresses a persistent issue of obtaining thick CNT carpets on temperature-sensitive substrates at low temperatures using a non-plasma CVD approach without catalyst pretreatment and/or preheating of the carbon feedstock. The efficiency of the process is evidenced by the highly dense, vertically aligned CNT structures from both Fe and Fe-Cu catalysts even at temperatures as low as 400 °C - a record low growth temperature for CNT carpets obtained via conventional thermal CVD. The grown CNTs exhibit a straight morphology with hollow interior and parallel graphitic planes along the tube walls. The apparent activation energies for CNT carpet growth on Fe and Fe-Cu catalysts are 0.71 and 0.54 eV, respectively. The synergistic effect of Fe and Cu show a strong dependence on the growth temperature, with Cu being more influential at temperatures higher than 450 °C. The low activation energies and long catalyst lifetimes observed are rationalized based on the unique composition of FTS-GP and Gibbs free energies for the decomposition reactions of the hydrocarbon components. The use of FTS-GP facilitates low-temperature growth of CNT carpets on traditional (alumina film) and nontraditional substrates (aluminum foil) and has the potential of enhancing CNT quality, catalyst lifetime, and scalability. PMID:27353432

  19. Methanol Droplet Extinction in Oxygen/Carbon-dioxide/Nitrogen Mixtures in Microgravity: Results from the International Space Station Experiments

    Science.gov (United States)

    Nayagam, Vedha; Dietrich, Daniel L.; Ferkul, Paul V.; Hicks, Michael C.; Williams, Forman A.

    2012-01-01

    Motivated by the need to understand the flammability limits of condensed-phase fuels in microgravity, isolated single droplet combustion experiments were carried out in the Combustion Integrated Rack Facility onboard the International Space Station. Experimental observations of methanol droplet combustion and extinction in oxygen/carbon-dioxide/nitrogen mixtures at 0.7 and 1 atmospheric pressure in quiescent microgravity environment are reported for initial droplet diameters varying between 2 mm to 4 mm in this study.The ambient oxygen concentration was systematically lowered from test to test so as to approach the limiting oxygen index (LOI) at fixed ambient pressure. At one atmosphere pressure, ignition and some burning were observed for an oxygen concentration of 13% with the rest being nitrogen. In addition, measured droplet burning rates, flame stand-off ratios, and extinction diameters are presented for varying concentrations of oxygen and diluents. Simplified theoretical models are presented to explain the observed variations in extinction diameter and flame stand-off ratios.

  20. Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C5H10O3 Diethyl carbonate (VMSD1111, LB5134_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C5H10O3 Diethyl carbonate (VMSD1111, LB5134_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  1. Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C5H10O3 Diethyl carbonate (VMSD1212, LB5137_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C5H10O3 Diethyl carbonate (VMSD1212, LB5137_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  2. Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H6O3 Dimethyl carbonate (VMSD1212, LB5136_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H6O3 Dimethyl carbonate (VMSD1212, LB5136_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  3. Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H6O3 Dimethyl carbonate (VMSD1111, LB5133_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl sulfoxide C2H6OS + C3H6O3 Dimethyl carbonate (VMSD1111, LB5133_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  4. Thermodynamic properties of binary mixtures containing dimethyl carbonate+2-alkanol: Experimental data, correlation and prediction by ERAS model and cubic EOS

    Science.gov (United States)

    Almasi, Mohammad

    2013-03-01

    Densities and viscosities for binary mixtures of dimethyl carbonate with 2-propanol up to 2-heptanol were measured at various temperatures and ambient pressure. From experimental data, excess molar volumes, VmE. were calculated and correlated by the Redlich-Kister equation to obtain the binary coefficients and the standard deviations. Excess molar volumes, VmE, are positive for all studied mixtures over the entire range of the mole fraction. The ERAS-model has been applied for describing the binary excess molar volumes and also Peng-Robinson-Stryjek-Vera (PRSV) equation of state (EOS) has been used to predict the binary excess molar volumes and viscosities. Also several semi-empirical models were used to correlate the viscosity of binary mixtures.

  5. Sorption of a phenols mixture in aqueous solution with activated carbon; Sorcion de una mezcla de fenoles en solucion acuosa con carbon activado

    Energy Technology Data Exchange (ETDEWEB)

    Mejia M, D

    2004-07-01

    The constant population growth and the quick industrialization have caused severe damages to our natural aquifer resources for a great variety of organic and inorganic pollutants. Among these they are those phenol compounds that are highly toxic, resistant (to the degradation chemistry) and poorly biodegradable. The phenolic compounds is used in a great variety of industries, like it is the production of resins, nylon, plastifiers, anti-oxidants, oil additives, drugs, pesticides, colorants, explosives, disinfectants and others. The disseminated discharges or effluents coming from the industrial processes toward lakes and rivers are causing a growing adverse effect in the environment, as well as a risk for the health. Numerous studies exist on the phenols removal and phenols substituted for very varied techniques, among them they are the adsorption in activated carbon. This finishes it has been used successfully for the treatment of residual waters municipal and industrial and of drinking waters and it is considered as the best technique available to eliminate organic compounds not biodegradable and toxic present in aqueous solution (US EPA, 1991). However a little information exists on studies carried out in aqueous systems with more of a phenolic compound. The activated carbon is broadly used as adsorbent due to its superficial properties in the so much treatment of water as of aqueous wastes, adsorbent for the removal of organic pollutants. The main objective of this work is the adsorption of a aqueous mixture of phenol-4 chloro phenol of different concentrations in activated carbon of mineral origin of different meshes and to diminish with it their presence in water. The experiments were carried out for lots, in normal conditions of temperature and pressure. The experimental results show that the removal capacity depends so much of the superficial properties of the sorbent like of the physical properties and chemical of the sorbate. The isotherms were carried

  6. The CPA Equation of State and an Activity Coefficient Model for Accurate Molar Enthalpy Calculations of Mixtures with Carbon Dioxide and Water/Brine

    OpenAIRE

    Myint, P. C.; Hao, Y.; Firoozabadi, A.

    2015-01-01

    Thermodynamic property calculations of mixtures containing carbon dioxide (CO$_2$) and water, including brines, are essential in theoretical models of many natural and industrial processes. The properties of greatest practical interest are density, solubility, and enthalpy. Many models for density and solubility calculations have been presented in the literature, but there exists only one study, by Spycher and Pruess, that has compared theoretical molar enthalpy predictions with experimental ...

  7. Removal of two ionic dyes from water by MgO-loaded porous carbons prepared through one-step process from poly(ethylene terephthalate)/magnesium carbonate mixtures

    Indian Academy of Sciences (India)

    A Czyżewski; J Karolczyk; A Usarek; J Przepiórski

    2012-04-01

    Mixtures of poly(ethylene terephthalate) and magnesium carbonate at different weight ratios were heated up to 850°C in argon atmosphere. During heating, components of the initial mixtures underwent thermal decomposition yielding porous carbon materials loaded with different amounts of magnesium oxide. Structural characteristics of the prepared materials were determined from adsorption/desorption isotherms of nitrogen, measured at 77 K. For reference, portions of the products obtained were acid-washed to obtain MgO-free carbons. Pore structures of the prepared materials were strongly dependent on the quantitative compositions of starting mixtures. As a rule, specific surface areas determined for acid-washed materials were much higher than those for MgO-loaded carbons. The adsorption abilities of obtained materials towards cationic (Basic Red 18) and anionic (Reactive Red 198) dyes as model contaminants were examined. Surprisingly, in spite of relatively low specific surface areas, substantially high adsorption of the dyes on MgO-loaded carbons was observed. An influence of specific surface area and the role of magnesium oxide presence on the adsorption capacity of the acquired sorbents were studied.

  8. Spectrographic determination of boron and silicon in uranium tetrafluoride: Study of the chemical reactions in the electrode cavity when ZnO is used as a uranium excitation suppressor

    International Nuclear Information System (INIS)

    A method has been developed for determining traces of boron and silicon in uranium tetrafluoride. Use is made of zinc oxide to decrease the volatilization of uranium and achieve high sensitivities. The thermochemical reactions which occur in the anode cavity during the arcing process have been investigated. UO2 and a uranium, zinc and fluorine compound, both less volatile than uranium tetrafluoride, are formed. (Author)

  9. FORMATION OF S-BEARING SPECIES BY VUV/EUV IRRADIATION OF H2S-CONTAINING ICE MIXTURES: PHOTON ENERGY AND CARBON SOURCE EFFECTS

    International Nuclear Information System (INIS)

    Carbonyl sulfide (OCS) is a key molecule in astrobiology that acts as a catalyst in peptide synthesis by coupling amino acids. Experimental studies suggest that hydrogen sulfide (H2S), a precursor of OCS, could be present in astrophysical environments. In the present study, we used a microwave-discharge hydrogen-flow lamp, simulating the interstellar UV field, and a monochromatic synchrotron light beam to irradiate CO:H2S and CO2:H2S ice mixtures at 14 K with vacuum ultraviolet (VUV) or extreme ultraviolet (EUV) photons in order to study the effect of the photon energy and carbon source on the formation mechanisms and production yields of S-containing products (CS2, OCS, SO2, etc.). Results show that (1) the photo-induced OCS production efficiency in CO:H2S ice mixtures is higher than that of CO2:H2S ice mixtures; (2) a lower concentration of H2S enhances the production efficiency of OCS in both ice mixtures; and (3) the formation pathways of CS2 differ significantly upon VUV and EUV irradiations. Furthermore, CS2 was produced only after VUV photoprocessing of CO:H2S ices, while the VUV-induced production of SO2 occurred only in CO2:H2S ice mixtures. More generally, the production yields of OCS, H2S2, and CS2 were studied as a function of the irradiation photon energy. Heavy S-bearing compounds were also observed using mass spectrometry during the warm-up of VUV/EUV-irradiated CO:H2S ice mixtures. The presence of S-polymers in dust grains may account for the missing sulfur in dense clouds and circumstellar environments

  10. FORMATION OF S-BEARING SPECIES BY VUV/EUV IRRADIATION OF H{sub 2}S-CONTAINING ICE MIXTURES: PHOTON ENERGY AND CARBON SOURCE EFFECTS

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.-J.; Juang, K.-J.; Qiu, J.-M.; Chu, C.-C.; Yih, T.-S. [Department of Physics, National Central University, Jhongli City, Taoyuan County 32054, Taiwan (China); Nuevo, M. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Jiménez-Escobar, A.; Muñoz Caro, G. M. [Centro de Astrobiología, INTA-CSIC, Torrejón de Ardoz, E-28850 Madrid (Spain); Wu, C.-Y. R. [Space Sciences Center and Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-1341 (United States); Fung, H.-S. [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Ip, W.-H. [Graduate Institute of Astronomy, National Central University, Jhongli City, Taoyuan County 32049, Taiwan (China)

    2015-01-10

    Carbonyl sulfide (OCS) is a key molecule in astrobiology that acts as a catalyst in peptide synthesis by coupling amino acids. Experimental studies suggest that hydrogen sulfide (H{sub 2}S), a precursor of OCS, could be present in astrophysical environments. In the present study, we used a microwave-discharge hydrogen-flow lamp, simulating the interstellar UV field, and a monochromatic synchrotron light beam to irradiate CO:H{sub 2}S and CO{sub 2}:H{sub 2}S ice mixtures at 14 K with vacuum ultraviolet (VUV) or extreme ultraviolet (EUV) photons in order to study the effect of the photon energy and carbon source on the formation mechanisms and production yields of S-containing products (CS{sub 2}, OCS, SO{sub 2}, etc.). Results show that (1) the photo-induced OCS production efficiency in CO:H{sub 2}S ice mixtures is higher than that of CO{sub 2}:H{sub 2}S ice mixtures; (2) a lower concentration of H{sub 2}S enhances the production efficiency of OCS in both ice mixtures; and (3) the formation pathways of CS{sub 2} differ significantly upon VUV and EUV irradiations. Furthermore, CS{sub 2} was produced only after VUV photoprocessing of CO:H{sub 2}S ices, while the VUV-induced production of SO{sub 2} occurred only in CO{sub 2}:H{sub 2}S ice mixtures. More generally, the production yields of OCS, H{sub 2}S{sub 2}, and CS{sub 2} were studied as a function of the irradiation photon energy. Heavy S-bearing compounds were also observed using mass spectrometry during the warm-up of VUV/EUV-irradiated CO:H{sub 2}S ice mixtures. The presence of S-polymers in dust grains may account for the missing sulfur in dense clouds and circumstellar environments.

  11. New (p, ρ, T) data for carbon dioxide - Nitrogen mixtures from (250 to 400) K at pressures up to 20 MPa

    International Nuclear Information System (INIS)

    Highlights: → Densities of two mixtures of nitrogen and carbon dioxide are reported. → Experimental data are compared with calculated densities from the equation of state. → Experimental data agree with the equation of state for low pressures above 300 K. → The equation of state shows higher deviations than expected at high pressures. - Abstract: Comprehensive (p, ρ, T) measurements on two binary mixtures (0.10 CO2 + 0.90 N2 and 0.15 CO2 + 0.85 N2) were carried out in the gas phase at seven isotherms between (250 and 400) K and pressures up to 20 MPa using a single sinker densimeter with magnetic suspension coupling. A total of 69 (p, ρ, T) data for the first mixture and 69 (p, ρ, T) data for the second are presented in this article. The uncertainty in density was estimated to be (0.02 to 0.15)%, while the uncertainty in temperature was 3.9 mK and the uncertainty in pressure was less than 0.015% (coverage factor k = 2). Experimental results were compared with densities calculated from the GERG equation of state and with data reported by other authors for similar mixtures. Results yielded that, while deviations between experimental data and values calculated from the GERG equation were lower than 0.05% in density for low pressures, the relative error at high pressures and low temperatures increased to about (0.2 to 0.3)%. The main aim of this work was to contribute to an accurate density data base for CO2/N2 mixtures and to check or improve equations of state existing for these binary mixtures.

  12. New (p, {rho}, T) data for carbon dioxide - Nitrogen mixtures from (250 to 400) K at pressures up to 20 MPa

    Energy Technology Data Exchange (ETDEWEB)

    Mondejar, M.E.; Martin, M.C. [Grupo de Termodinamica y Calibracion (TERMOCAL), Dpto. Ingenieria Energetica y Fluidomecanica, Escuela de Ingenierias Industriales, Universidad de Valladolid, Paseo del Cauce, 59, E-47011 Valladolid (Spain); Span, R. [Lehrstuhl fuer Thermodynamik, Fakultaet fuer Maschinenbau Gebaeude IB, Ebene 5, Ruhr-Universitaet Bochum, Universitaetsstr. 150, 44780 Bochum (Germany); Chamorro, C.R., E-mail: cescha@eis.uva.es [Grupo de Termodinamica y Calibracion (TERMOCAL), Dpto. Ingenieria Energetica y Fluidomecanica, Escuela de Ingenierias Industriales, Universidad de Valladolid, Paseo del Cauce, 59, E-47011 Valladolid (Spain)

    2011-12-15

    Highlights: > Densities of two mixtures of nitrogen and carbon dioxide are reported. > Experimental data are compared with calculated densities from the equation of state. > Experimental data agree with the equation of state for low pressures above 300 K. > The equation of state shows higher deviations than expected at high pressures. - Abstract: Comprehensive (p, {rho}, T) measurements on two binary mixtures (0.10 CO{sub 2} + 0.90 N{sub 2} and 0.15 CO{sub 2} + 0.85 N{sub 2}) were carried out in the gas phase at seven isotherms between (250 and 400) K and pressures up to 20 MPa using a single sinker densimeter with magnetic suspension coupling. A total of 69 (p, {rho}, T) data for the first mixture and 69 (p, {rho}, T) data for the second are presented in this article. The uncertainty in density was estimated to be (0.02 to 0.15)%, while the uncertainty in temperature was 3.9 mK and the uncertainty in pressure was less than 0.015% (coverage factor k = 2). Experimental results were compared with densities calculated from the GERG equation of state and with data reported by other authors for similar mixtures. Results yielded that, while deviations between experimental data and values calculated from the GERG equation were lower than 0.05% in density for low pressures, the relative error at high pressures and low temperatures increased to about (0.2 to 0.3)%. The main aim of this work was to contribute to an accurate density data base for CO{sub 2}/N{sub 2} mixtures and to check or improve equations of state existing for these binary mixtures.

  13. Synthesis of single-walled carbon nanotubes by the pyrolysis of a compression activated iron(II) phthalocyanine/phthalocyanine metal-free derivative/ferric acetate mixture

    Indian Academy of Sciences (India)

    Tawanda Mugadza; Edith Antunes; Tebello Nyokong

    2015-07-01

    This paper reports on the synthesis of single walled carbon nanotubes (SWCNTs) from an activated mixture of iron (II) phthalocyanine, its metal-free derivative and ferric acetate. The powdered mixture was activated by compression into a tablet by applying a force of 300 kN, followed by re-grinding into powder and heating it to high temperatures (1000°C). The activation by compression resulted in more than 50% debundling of SWCNTs as judged by transition electron microscopy. Acid functionalization of the SWCNTs was confirmed by the increase in the D:G ratio from 0.56 to 0.87 in the Raman spectra and the observation of an average of one carboxylic acid group per 13 carbon atoms from thermogravimetric analysis (TGA). TGA also showed that the initial decomposition temperatures for the activated and non-activated mixtures to be 205°C and 245°C, respectively. Hence, activation leads to the lowering of the pyrolysis temperature of the phthalocyanines. X-ray diffraction, electronic absorption and Fourier transform infrared spectra were also employed to characterize the SWCNT.

  14. Microporous-mesoporous carbons for energy storage synthesized by activation of carbonaceous material by zinc chloride, potassium hydroxide or mixture of them

    Science.gov (United States)

    Härmas, M.; Thomberg, T.; Kurig, H.; Romann, T.; Jänes, A.; Lust, E.

    2016-09-01

    Various electrochemical methods have been applied to establish the electrochemical characteristics of the electrical double layer capacitor (EDLC) consisting of the 1 M triethylmethylammonium tetrafluoroborate solution in acetonitrile and activated carbon based electrodes. Activated microporous carbon materials used for the preparation of electrodes have been synthesized from the hydrothermal carbonization product (HTC) prepared via hydrothermal carbonization process of D-(+)-glucose solution in H2O, followed by activation with ZnCl2, KOH or their mixture. Highest porosity and Brunauer-Emmett-Teller specific surface area (SBET = 2150 m2 g-1), micropore surface area (Smicro = 2140 m2 g-1) and total pore volume (Vtot = 1.01 cm3 g-1) have been achieved for HTC activated using KOH with a mass ratio of 1:4 at 700 °C. The correlations between SBET, Smicro, Vtot and electrochemical characteristics have been studied to investigate the reasons for strong dependence of electrochemical characteristics on the synthesis conditions of carbon materials studied. Wide region of ideal polarizability (ΔV ≤ 3.0 V), very short characteristic relaxation time (0.66 s), and high specific series capacitance (134 F g-1) have been calculated for the mentioned activated carbon material, demonstrating that this system can be used for completing the EDLC with high energy- and power densities.

  15. Estimation of the minimum Prandtl number for binary gas mixtures formed with light helium and certain heavier gases: Application to thermoacoustic refrigerators

    International Nuclear Information System (INIS)

    This paper addresses a detailed procedure for the accurate estimation of low Prandtl numbers of selected binary gas mixtures. In this context, helium (He) is the light primary gas and the heavier secondary gases are nitrogen (N2), oxygen (O2), xenon (Xe), carbon dioxide (CO2), methane (CH4), tetrafluoromethane or carbon tetrafluoride (CF4) and sulfur hexafluoride (SF6). The three thermophysical properties forming the Prandtl number of binary gas mixtures Prmix are heat capacity at constant pressure Cp,mix (thermodynamic property), viscosity ηmix (transport property) and thermal conductivity λmix (transport property), which in general depend on temperature T and molar gas composition w. The precise formulas for the calculation of the trio Cp,mix, ηmix, and λmix are gathered from various dependable sources. When the set of computed Prmix values for the seven binary gas mixtures He + N2, He + O2, He + Xe, He + CO2, He + CH4, He + CF4, He + SF6 at atmospheric conditions T = 300 K, p = 1 atm is plotted against the molar gas composition w on the w-domain [0,1], the family of Prmix(w) curves exhibited distinctive concave shapes. In the curves format, all Prmix(w) curves initiate with Pr ∼ 0.7 at w = 0 (associated with light primary He). Forthwith, each Prmix(w) curve descends to a unique minimum and thereafter ascend back to Pr ∼ 0.7 at the terminal point w = 1 (connected to heavier secondary gases). Overall, it was found that among the seven binary gas mixtures tested, the He + Xe gas mixture delivered the absolute minimum Prandtl number Prmix,min = 0.12 at the optimal molar gas composition wopt = 0.975. - Highlights: →Accurate estimation of low Prandtl numbers for some helium-based binary gas mixtures. →The thermophysical properties of the gases are calculated with precise formulas. →The absolute minimum Prandtl number is delivered by the He + Xe binary gas mixture. →Application to experimental thermoacoustic refrigerators

  16. Ionic molar volumes in methanol mixtures with acetonitrile, N,N-dimethylformamide and propylene carbonate at T = 298.15 K

    International Nuclear Information System (INIS)

    Highlights: • Densities of electrolyte solutions in methanol mixtures were measured at T = 298.15 K. • Apparent molar volumes of sodium cation and iodide anion were determined. • TPTB as a calculation method was used. • Preferential solvation of ions by organic solvents was examined. - Abstract: The densities of dilute solutions of three electrolytes (NaI, NaBPh4 and Ph4PI) in methanol mixtures with propylene carbonate (PC), N,N-dimethylformamide (DMF) and acetonitrile (AN) have been measured by Anton Paar 5000 densimeter at T = 298.15 K. Apparent molar volumes, VΦ have been determined at an electrolyte concentration of 0.06 mol · kg−1 over the entire mixed solvent composition range. Single ionic apparent molar volumes of transfer, ΔtVΦ (ion) were calculated using the tetraphenylphosphonium tetraphenylborate (TPTB) assumption. The results are discussed in terms of ionic preferential solvation

  17. Methods for the preparation of ultra-pure anhydrous zirconium tetrafluoride from zirconium tetraborohydride, researches in connection with halide glasses

    International Nuclear Information System (INIS)

    The synthesis of ultrapure zirconium tetrafluoride, the main component of fluorozirconate based optical fibers, was successfully attempted from zirconium tetraborohydride. Of the fluorinating agents used, nitrogen trifluoride doesn't react with zirconium tetraborohydride while xenon difluoride reacts too violently and leads to phases which contain boron. The fluorination in a compatible solvent enabled us to minimize the degradation. The best results were obtained with the fluorination of Zr(BH4)4 dissolved in CFCl3 at -40 deg C by anhydrous HF. Using several analytical methods such as graphite furnace atomic absorption and proton activation, we analyzed the purity. The degree of transition element impurities is less than the ppm level for ZrF4. The dehydration of ZrF4,H2O and ZrF4,3H2O at room temperature by CIF3 in gaseous and liquid state was also investigated. At exceptionally low temperature, this process allows oxide and oxyfluoride components to be reduced

  18. Transport properties in mixtures involving carbon dioxide at low and moderate density: test of several intermolecular potential energies and comparison with experiment

    Energy Technology Data Exchange (ETDEWEB)

    Moghadasi, Jalil; Yousefi, Fakhri [Shiraz University, Department of Chemistry, Shiraz (Iran); Papari, Mohammad Mehdi; Faghihi, Mohammad Ali [Shiraz University of Technology, Department of Chemistry, Shiraz (Iran); Mohsenipour, Ali Asghar [University of Waterloo, Department of Chemical Engineering, Waterloo (Canada)

    2009-09-15

    It is the purpose of this paper to extract unlike intermolecular potential energies of five carbon dioxide-based binary gas mixtures including CO{sub 2}-He, CO{sub 2}-Ne, CO{sub 2}-Ar, CO{sub 2}-Kr, and CO{sub 2}-Xe from viscosity data and compare the calculated potentials with other models potential energy reported in literature. Then, dilute transport properties consisting of viscosity, diffusion coefficient, thermal diffusion factor, and thermal conductivity of aforementioned mixtures are calculated from the calculated potential energies and compared with literature data. Rather accurate correlations for the viscosity coefficient of afore-cited mixtures embracing the temperature range 200 K

  19. One-step "green" preparation of graphene nanosheets and carbon nanospheres mixture by electrolyzing graphite rob and its application for glucose biosensing.

    Science.gov (United States)

    Yin, Huanshun; Zhou, Yunlei; Meng, Xiaomeng; Shang, Kun; Ai, Shiyun

    2011-12-15

    The graphene nanosheets and carbon nanospheres mixture (GNS-CNS) was prepared by electrolyzing graphite rob in KNO(3) solution under constant current, which was characterized by TEM, AFM, SEM, FT-IR, XRD, XPS, TGA and UV-vis. The nano-mixture can keep stable in water for more than one month. Based on this kind of mixture material, a novel electrochemical biosensing platform for glucose determination was developed. Cyclic voltammetry of glucose oxidase (GOD) immobilized on GNS-CNS/GCE exhibited a pair of well-defined quasi-reversible redox peaks at -0.488 V (E(pa)) and -0.509 V (E(pc)) by direct electron transfer between the protein and the electrode. The charge-transfer coefficient (α) was 0.51, the electron transfer rate constant was 2.64 s(-1) and the surface coverage of HRP was 3.18×10(-10) mol cm(-2). The immobilized GOD could retain its bioactivity and catalyze the reduction of dissolved oxygen. The glucose biosensor has a linear range from 0.4 to 20 mM with detection limit of 0.1 mM. Moreover, the biosensor exhibits acceptable reproducibility and storage stability. The fabricated biosensor was further used to determine glucose in human plasma sample with the recoveries from 96.83% to 105.52%. Therefore, GOD/GNS-CNS/GCE could be promisingly applied to determine blood sugar concentration in the practical clinical analysis. PMID:21959225

  20. Effects of Microporosity and Surface Chemistry on Separation Performances of N-Containing Pitch-Based Activated Carbons for CO2/N2 Binary Mixture

    Science.gov (United States)

    Lee, Min-Sang; Park, Mira; Kim, Hak Yong; Park, Soo-Jin

    2016-03-01

    In this study, N-containing pitch-based activated carbons (NPCs) were prepared using petroleum pitch with a low softening point and melamine with a high nitrogen content. The major advantage of the preparation method is that it enables variations in chemical structures and textural properties by steam activation at high temperatures. The adequate micropore structures, appropriate chemical modifications, and high adsorption enthalpies of NPCs are favorable for CO2 adsorption onto carbon surfaces. Furthermore, the structure generates a considerable gas/N-containing carbon interfacial area, and provides selective access to CO2 molecules over N2 molecules by offering an increased number of active sites on the carbon surfaces. The highest CO2/N2 selectivity, i.e., 47.5, and CO2 adsorption capacity for a CO2/N2 (0.15:0.85) binary gas mixture, i.e., 5.30 wt%, were attained at 298 K. The NPCs also gave reversible and durable CO2-capturing performances. All the results suggest that NPCs are promising CO2 sorbents, which can meet the challenges of current CO2 capture and separation techniques.

  1. Effects of Microporosity and Surface Chemistry on Separation Performances of N-Containing Pitch-Based Activated Carbons for CO2/N2 Binary Mixture

    Science.gov (United States)

    Lee, Min-Sang; Park, Mira; Kim, Hak Yong; Park, Soo-Jin

    2016-01-01

    In this study, N-containing pitch-based activated carbons (NPCs) were prepared using petroleum pitch with a low softening point and melamine with a high nitrogen content. The major advantage of the preparation method is that it enables variations in chemical structures and textural properties by steam activation at high temperatures. The adequate micropore structures, appropriate chemical modifications, and high adsorption enthalpies of NPCs are favorable for CO2 adsorption onto carbon surfaces. Furthermore, the structure generates a considerable gas/N-containing carbon interfacial area, and provides selective access to CO2 molecules over N2 molecules by offering an increased number of active sites on the carbon surfaces. The highest CO2/N2 selectivity, i.e., 47.5, and CO2 adsorption capacity for a CO2/N2 (0.15:0.85) binary gas mixture, i.e., 5.30 wt%, were attained at 298 K. The NPCs also gave reversible and durable CO2-capturing performances. All the results suggest that NPCs are promising CO2 sorbents, which can meet the challenges of current CO2 capture and separation techniques. PMID:26987683

  2. Inhibition of the ultrasonic microjet-pits on the carbon steel in the particles-water mixtures

    OpenAIRE

    Dayun Yan; Jiadao Wang; Fengbin Liu

    2015-01-01

    In the incubation period of ultrasonic cavitation, due to the impact of microjets on the material surface, the needle-like microjet-pits are formed. Because the formation of microjet-pits relates with the evolution of cavitation erosion on engineering materials, corresponding study will promote the understanding on the mechanism of cavitation erosion. However, little study on the microjet-pits has been carried out, especially in the particles-water mixture. In this study, we firstly demonstra...

  3. The CPA Equation of State and an Activity Coefficient Model for Accurate Molar Enthalpy Calculations of Mixtures with Carbon Dioxide and Water/Brine

    Energy Technology Data Exchange (ETDEWEB)

    Myint, P. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hao, Y. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Firoozabadi, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-03-27

    Thermodynamic property calculations of mixtures containing carbon dioxide (CO2) and water, including brines, are essential in theoretical models of many natural and industrial processes. The properties of greatest practical interest are density, solubility, and enthalpy. Many models for density and solubility calculations have been presented in the literature, but there exists only one study, by Spycher and Pruess, that has compared theoretical molar enthalpy predictions with experimental data [1]. In this report, we recommend two different models for enthalpy calculations: the CPA equation of state by Li and Firoozabadi [2], and the CO2 activity coefficient model by Duan and Sun [3]. We show that the CPA equation of state, which has been demonstrated to provide good agreement with density and solubility data, also accurately calculates molar enthalpies of pure CO2, pure water, and both CO2-rich and aqueous (H2O-rich) mixtures of the two species. It is applicable to a wider range of conditions than the Spycher and Pruess model. In aqueous sodium chloride (NaCl) mixtures, we show that Duan and Sun’s model yields accurate results for the partial molar enthalpy of CO2. It can be combined with another model for the brine enthalpy to calculate the molar enthalpy of H2O-CO2-NaCl mixtures. We conclude by explaining how the CPA equation of state may be modified to further improve agreement with experiments. This generalized CPA is the basis of our future work on this topic.

  4. Semi-automatic determination of the carbon and oxygen stable isotope compositions of calcite and dolomite in natural mixtures

    International Nuclear Information System (INIS)

    A semi-automatic, on-line method was developed to determine the δ13C and δ18O values of coexisting calcite and dolomite. An isotopic mass balance is used to calculate the compositions of dolomite after having measured that of calcite and of the “bulk” sample. The limit of validity of this method is established by performing isotopic measurements of artificial mixtures made of precisely weighted and isotopically-characterised dolomite and calcite. The accuracy and repeatability of the calculation of dolomite δ13C and δ18O are statistically determined with a Monte-Carlo procedure of error propagation. Stable isotope ratios are determined by using an automated MultiPrep™ system on-line with an isotope-ratio mass-spectrometer (IRMS). The reaction time and the temperature of reaction were optimised by comparing the results with the isotopic composition of known mixtures. The best results were obtained by phosphoric acid digestion after 20 min at 40 °C for calcite and 45 min at 90 °C for dolomite. This procedure allows an accurate determination of the isotopic ratios from small samples (300 μg). Application of this protocol to natural mixtures of calcite and dolomite requires the accurate determination of the relative abundance of calcite and dolomite by combining Mélières manocalcimetry (MMC) and X-ray diffractometry (XRD).

  5. Total electron yield soft x-ray absorption spectroscopy in the C K region of the mixtures of graphitic carbons and diamond for quantitative analysis of the sp2/sp3-hybridized carbon ratio

    International Nuclear Information System (INIS)

    To elucidate the possibility of quantitatively analyzing sp2-hybridized carbon (sp2-C) and sp3-C in carbon materials using total-electron-yield (TEY) X-ray absorption spectra (XAS) in the C K region, we measured the TEY-XAS of mixtures of multi-walled carbon nanotubes or carbon black as sp2-C sources and diamond as an sp3-C source. The measured relationship between the π*/σ* peak intensity ratio in the C K TEY-XAS and the weight (atomic)% of sp2-C can be successfully explained by the summed TEY of the sp2-C and sp3-C components and considering the TEY efficiency of sp3-C relative to sp2-C, k. However, the experimentally determined k values show that TEY of the sp3-C is much smaller than that of sp2-C by about one order of magnitude, even depending on the chemical form and/or electronic properties of individual carbon components. This suggests that further evaluation of the TEY efficiency is necessary prior to the quantitative sp2/sp3 analysis of carbon materials using the TEY-XAS. (author)

  6. Hydrate-based removal of carbon dioxide and hydrogen sulphide from biogas mixtures: Experimental investigation and energy evaluations

    International Nuclear Information System (INIS)

    This paper presents an experimental study on the application of gas hydrate technology to biogas upgrading. Since CH4, CO2 and H2S form hydrates at quite different thermodynamic conditions, the capture of CO2 and H2S by means of gas hydrate crystallization appears to be a viable technological alternative for their removal from biogas streams. Nevertheless, hydrate-based biogas upgrading has been poorly investigated. Works found in literature are mainly at a laboratory scale and concern with thermodynamic and kinetic fundamental studies. The experimental campaign was carried out with an up-scaled apparatus, in which hydrates are produced in a rapid manner, with hydrate formation times of few minutes. Two types of mixtures were used: a CH4/CO2 mixture and a CH4/CO2/H2S mixture. The objective of the investigation is to evaluate the selectivity and the separation efficiency of the process and the role of hydrogen sulphide in the hydrate equilibrium. Results show that H2S can be captured along with CO2 in the same process. The maximum value of the separation factor, defined as the ratio between the number of moles of CO2 and the number of moles of CH4 removed from the gas phase, is 11. In the gas phase, a reduction of CO2 of 24.5% in volume is achievable in 30 min. Energy costs of a real 30-min separation process, carried out in the experimental campaign, are evaluated and compared with those obtained from theoretical calculations. Some aspects for technology improvement are discussed. - Highlights: • Tests on CO2 and H2S removal from biogas mixture via gas hydrates were carried out. • An up-scaled apparatus was used with hydrate formation times of few minutes. • CO2 hydrates were produced through spraying aqueous solution into the gas phase. • H2S was completely captured along with CO2 in 30- minute formation process. • Aspects for process improvement and energy costs are evaluated

  7. Effect of deposition temperature on boron-doped carbon coatings deposited from a BCl3-C3H6-H2 mixture using low pressure chemical vapor deposition

    International Nuclear Information System (INIS)

    A mixture of propylene, hydrogen and boron trichloride was used to fabricate boron-doped carbon coatings by using low pressure chemical vapor deposition (LPCVD) technique. Effect of deposition temperature on deposition rate, morphologies, compositions and bonding states of boron-doped carbon coatings was investigated. Below 1273 K, the deposition rate is controlled by reaction dynamics. The deposition rate increases with increasing deposition temperature. The activation energy is 208.74 kJ/mol. Above 1273 K, the deposition rate decreases due to smaller critical radius rc and higher nuclei formation rate J with increasing temperature. Scanning electron microscopy shows that the structure changes from glass-like to nano-laminates with increasing deposition temperature. The boron concentration decreases with increasing deposition temperature, corresponding with increasing carbon concentration. The five types of bonding states are B-C, B-sub-C, BC2O, BCO2 and B-O. B-sub-C and BC2O are the main bonding states. The reactions are dominant at all temperatures, in which the B-sub-C and PyC are formed.

  8. Investigation of HCCI Combustion of Diethyl Ether and Ethanol Mixtures Using Carbon 14 Tracing and Numerical Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Mack, J H; Dibble, R W; Buchholz, B A; Flowers, D L

    2004-01-16

    Despite the rapid combustion typically experienced in Homogeneous Charge Compression Ignition (HCCI), components in fuel mixtures do not ignite in unison or burn equally. In our experiments and modeling of blends of diethyl ether (DEE) and ethanol (EtOH), the DEE led combustion and proceeded further toward completion, as indicated by {sup 14}C isotope tracing. A numerical model of HCCI combustion of DEE and EtOH mixtures supports the isotopic findings. Although both approaches lacked information on incompletely combusted intermediates plentiful in HCCI emissions, the numerical model and {sup 14}C tracing data agreed within the limitations of the single zone model. Despite the fact that DEE is more reactive than EtOH in HCCI engines, they are sufficiently similar that we did not observe a large elongation of energy release or significant reduction in inlet temperature required for light-off, both desired effects for the combustion event. This finding suggests that, in general, HCCI combustion of fuel blends may have preferential combustion of some of the blend components.

  9. In vitro solubility of uranium tetrafluoride with oxidizing medium compared with in vivo solubility in rats

    International Nuclear Information System (INIS)

    A simple in vitro solubility test for UF4 was developed to investigate effects of addition of enzymes, proteins or gases (eg O2) to synthetic biological fluid or Gamble solvent. Tests were made concomitantly with an in vivo inhalation study using male rats. With Gamble solvent alone, UF4 showed class Y behaviour with dissolution half-time 300-500 days. When O2 or carbonates were added to Gamble solvent, UF4 showed class W behaviour (half-time 25-50 days). In the presence of oxygen and pyrogallol, the superoxide ion was formed and UF4 behaved as class D (half-time 2-3 days). Results correlated with those of the inhalation experiment in which dissolution half-time was 2.5 and 5.2 days. Data also agree with urine monitoring data for workers exposed to UF4 over 20 years. (author)

  10. Percolation-dominated superhydrophobicity and conductivity for nanocomposite coatings from the mixtures of a commercial aqueous silica sol and functionalized carbon nanotubes.

    Science.gov (United States)

    Peng, Mao; Guo, Honglei; Liao, Zhangjie; Qi, Ji; Zhou, Zhi; Fang, Zhengping; Shen, Lie

    2012-02-01

    Superhydrophobic conductive nanocomposite coatings are prepared for the first time from the simple mixture of a commercial aqueous silica sol and functionalized multiwalled carbon nanotubes (MWNTs) by air-spraying at ambient conditions followed by fluorosilane treatment. The relationship between MWNT content and the structure and properties of the nanocomposite coatings is investigated systematically. An ultra-low threshold (165°) and extremely low sliding angles (<2°). The conductivity is also percolation dominated, while the threshold for conductivity is much higher than that for superhydrophobicity, which can be ascribed to the encapsulated structure and the agglomeration of nanotubes in the composite coatings during air-spraying. Moreover, the aqueous silica sols hold merits of great film-forming capability at relatively low calcination temperatures, and being free of organic solvents. PMID:22056263

  11. Gas barrier properties of hydrogenated amorphous carbon films coated on polyethylene terephthalate by plasma polymerization in argon/n-hexane gas mixture

    International Nuclear Information System (INIS)

    Hydrogenated amorphous carbon thin films were deposited by RF plasma polymerization in argon/n-hexane gas mixture on polyethylene terephthalate (PET) foils. It was found that such deposited films may significantly improve the barrier properties of PET. It was demonstrated that the principal parameter that influences barrier properties of such deposited films towards oxygen and water vapor is the density of the coatings. Moreover, it was shown that for achieving good barrier properties it is advantageous to deposit coatings with very low thickness. According to the presented results, optimal thickness of the coating should not be higher than several tens of nm. - Highlights: • a-C:H films were prepared by plasma polymerization in Ar/n-hexane atmosphere. • Barrier properties of coatings are dependent on their density and thickness. • Highest barrier properties were observed for films with thickness 15 nm

  12. Selective and Scalable Chemical Removal of Thin Single-Walled Carbon Nanotubes from their Mixtures with Double-Walled Carbon Nanotubes

    Czech Academy of Sciences Publication Activity Database

    Komínková, Zuzana; Valeš, Václav; Kalbáč, Martin

    2015-01-01

    Roč. 21, č. 45 (2015), s. 16147. ISSN 1521-3765 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388955 Keywords : carbon nanotubes * electrochemical doping * in-situ Raman spectroelectrochemistry Subject RIV: CG - Electrochemistry

  13. Natural gas processing using mixtures of glycols and alcohols for removal of water, heavy hydrocarbons and carbon dioxide

    OpenAIRE

    Auran, Ole Christian

    2014-01-01

    Developing new gas fields in cold and harsh environment requires cost effective technology for removal of water, heavy hydrocarbons (HHC) and carbon dioxide. Operating at such low temperatures requires a technology that do not experience freeze out and prevents hydrate formation. Mono- Ethylene Glycol (MEG) and methanol (MeOH) are both used as hydrate inhibitors in the industry today. Freezing point of MEG and MeOH is -13°C and -98°, respectively. By mixing MeOH and MEG together, a ...

  14. Influence of the glass-calcium carbonate mixture's characteristics on the foaming process and the properties of the foam glass

    DEFF Research Database (Denmark)

    König, Jakob; Petersen, Rasmus Rosenlund; Yue, Yuanzheng

    2014-01-01

    We prepared foam glasses from cathode-ray-tube panel glass and CaCO3 as a foaming agent. We investigated the influences of powder preparation, CaCO3 concentration and foaming temperature and time on the density, porosity and homogeneity of the foam glasses. The results show that the decomposition...... kinetics of CaCO3 has a strong influence on the foaming process. The decomposition temperature can be modified by varying the milling time of the glass–CaCO3 mixture and thus for a specific CaCO3 concentration an optimum milling time exists, at which a minimum in density and a homogeneous closed porosity...... are obtained. Under the optimum preparation conditions the samples exhibit a density of 260 kg/m3. The thermal conductivity of the foam glass was measured to be 50–53 mW/(m K). The observed dependence of the foaming process on the decomposition kinetics of the foaming agent can be applied as a...

  15. Solubilities of carbon dioxide in the eutectic mixture of levulinic acid (or furfuryl alcohol) and choline chloride

    International Nuclear Information System (INIS)

    Highlights: • Solubilities of carbon dioxide in six renewable deep eutectic solvents (DESs) have been reported. • The experimental data were well correlated by Henry’s law. • The dissolution Gibbs free energy, enthalpy, and entropy changes were derived. • The absorption capacities of CO2 in present DESs and other DESs as well as several ionic liquids were compared. - Abstract: The solubilities of carbon dioxide (CO2) in the renewable deep eutectic solvents (DESs) containing levulinic acid (or furfuryl alcohol) and choline chloride were determined at temperatures (303.15, 313.15, 323.15, and 333.15) K and pressures up to 600.0 kPa using an isochoric saturation method. The mole ratios of levulinic acid (or furfuryl alcohol) to choline chloride were fixed at 3:1, 4:1 and 5:1. Standard Gibbs free energy, dissolution enthalpy and dissolution entropy were calculated from Henry’s law constant of CO2 in the DESs. Results indicated that levulinic acid based DESs are more effective to capture CO2 than furfuryl alcohol based ones. The solubility of CO2 in the DESs increased with increasing mole ratio of levulinic acid (or furfuryl alcohol) to choline chloride as well as pressure and decreased with increasing temperature

  16. Application of surface-modified metal hydrides for hydrogen separation from gas mixtures containing carbon dioxide and monoxide

    International Nuclear Information System (INIS)

    Highlights: ► Application of surface-modified AB5 for H2 separation. ► Upscale of the surface modification procedure (up to 1.5 kg of AB5 substrate). ► Integration of the surface-modified AB5-type materials in H2 separation systems. ► Stable performances throughout 250 absorption/desorption cycles. ► The total process productivity is limited by slow selective H2 absorption. -- Abstract: Application of surface-modified MH material for H2 separation using temperature/pressure swing absorption–desorption was studied. The substrate alloy had the following composition LaNi3.55Co0.75Al0.4Mn0.3, and the surface modification was carried out through fluorination followed by aminosilane functionalization and electroless deposition of Pd. The material was found to have good poisoning tolerance towards surface adsorbates, even for the large (∼1.5 kg) batches. Feasibility of its application for H2 separation from gas mixtures (up to 30% CO2 and 100 ppm CO) was demonstrated by testing of a prototype H2 separation system (∼280 g of MH in two reactors), and H2 separation reactor (0.75 kg of MH). The H2 separation was characterized by stable performances in the duration of 250 absorption/desorption cycles. However, the total process productivity was found to be limited by the sluggish H2 absorption (partial H2 pressure ⩽2.5 bar, temperature below 100 °C). In the presence of CO2 and CO, additional deceleration of H2 absorption was observed at space velocities of the feed gas below 5000 h−1

  17. Structural characteristics of copper/hydrogenated amorphous carbon composite films prepared by microwave plasma-assisted deposition processes from methane-argon and acetylene-argon gas mixtures

    International Nuclear Information System (INIS)

    Copper/hydrogenated amorphous carbon (Cu/a-C:H) composite films have been deposited on silicon substrates by a hybrid technique combining microwave plasma-assisted chemical vapor deposition and sputter-deposition from methane-argon and acetylene-argon gas mixtures. The major objective of this work was to investigate the effect of the carbon gas precursor on the structural characteristics of Cu/a-C:H composite films deposited at ambient temperature. The major characteristics of CH4-argon and C2H2-argon plasmas were analyzed by Langmuir probe measurements. The composition of films was determined by Rutherford backscattering spectroscopy, energy recoil detection analyses and nuclear reaction analyses. The carbon content in the films was observed to vary in the range 20-77 at.% and 7.5-99 at.% as the CH4 and C2H2 concentrations in the gas phase increased from 10 to 100%, respectively. The atom number ratio H/C in the films was scattered approximately 0.4 whatever the carbon gas precursor used. The crystallographic structure and the size of copper crystallites incorporated in the a-C were determined by X-ray diffraction techniques. The copper crystallite size decreased from 20 nm in pure copper films to less than 5 nm in Cu/a-C:H films containing more than 40 at.% of carbon. Grazing incidence small angle X-ray scattering measurements were performed to investigate the size distribution and distance of copper crystallites as functions of the deposition parameters. The structural characteristics of copper crystallites were dependent on the hydrocarbon gas precursor used. The crystallite size and the width of the size distribution were homogeneous in films deposited from CH4. Copper crystallites with an anisotropic shape were found in films deposited from C2H2. The major radicals formed in the plasma and condensed on the surface of growing films, namely CH and C2H radicals for films produced from CH4 and C2H2, respectively, play probably a crucial role in the growth

  18. Short-term dynamics of carbon and nitrogen using compost, compost-biochar mixture and organo-mineral biochar.

    Science.gov (United States)

    Darby, Ian; Xu, Cheng-Yuan; Wallace, Helen M; Joseph, Stephen; Pace, Ben; Bai, Shahla Hosseini

    2016-06-01

    This study aims to examine the effects of different organic treatments including compost (generated from cattle hide waste and plant material), compost mixed with biochar (compost + biochar) and a new formulation of organo-mineral biochar (produced by mixing biochar with clay, minerals and chicken manure) on carbon (C) nitrogen (N) cycling. We used compost at the rate of 20 t ha(-1), compost 20 t ha(-1) mixed with 10 t ha(-1) biochar (compost + biochar) and organo-mineral biochar which also contained 10 t ha(-1) biochar. Control samples received neither of the treatments. Compost and compost + biochar increased NH4 (+) -N concentrations for a short time, mainly due to the release of their NH4 (+) -N content. Compost + biochar did not alter N cycling of the compost significantly but did significantly increase CO2 emission compared to control. Compost significantly increased N2O emission compared to control. Compost + biochar did not significantly change N supply and also did not decrease CO2 and N2O emissions compared to compost, suggesting probably higher rates of biochar may be required to be added to the compost to significantly affect compost-induced C and N alteration. The organo-mineral biochar had no effect on N cycling and did not stimulate CO2 and N2O emission compared to the control. However, organo-mineral biochar maintained significantly higher dissolved organic carbon (DOC) than compost and compost + biochar from after day 14 to the end of the incubation. Biochar used in organo-mineral biochar had increased organic C adsorption which may become available eventually. However, increased DOC in organo-mineral biochar probably originated from both biochar and chicken manure which was not differentiated in this experiment. Hence, in our experiment, compost, compost + biochar and organo-mineral biochar affected C and N cycling differently mainly due to their different content. PMID:26924699

  19. Intermolecular, ion-molecular and interionic interactions in solutions of lithium and tetrabutylammonium salts in mixtures of methanol with propylene carbonate

    International Nuclear Information System (INIS)

    Interparticle interactions are investigated in solutions of LiI, LiBr, LiCl, LiNCS, (C4H9)4NI, (C4H9)4NBr, (C4H9)4NCl in mixtures of methanol with propylene carbonate in absence of self-association of molecules of methanol and in different salt concentrations by the methods of IR spectroscopy. Intermolecular and ion-molecular interactions are studied on IR absorption lines of valent vibrations of OH-groups of methanol (3300-3500 cm-1), interionic interaction - on lines of valent CN (2000-2100 cm-1) and deformation O-Cl-O (625 cm-1) vibrations of NVS- and ClO4- correspondingly. Concentrations of lithium complexes forming in solutions are calculated on intensities of valent absorption lines of OH-groups of methanol. In the case of salt concentration increase the content of complexes decreases. Ousting of solvent molecule by anions in complex happens so faster as electron-donor ability of it is higher

  20. Effect of inorganic inhibitors on the corrosion behavior of 1018 carbon steel in the LiBr + ethylene glycol + H2O mixture

    International Nuclear Information System (INIS)

    The effect of inorganic inhibitors on the corrosion behavior of 1018 carbon steel in the mixture LiBr (55%) + ethylene glycol + H2O at room temperature has been evaluated. Used inhibitors included LiNO3 (Lithium Nitrate), Li2MoO4 (Lithium Molybdate) and Li2CrO4 (Lithium Chromate) at concentrations of 5, 20 and 50 ppm. Electrochemical techniques included potentiodynamic polarization curves, electrochemical noise resistance (EN) and electrochemical impedance spectroscopy (EIS) measurements. Additionally, adsorption isotherms were calculated. The results obtained showed that both, the corrosion rate and the passive current density decreased with inhibitors, and, in general terms, inhibitors efficiency increased with inhibitor concentration, except in the case of Li2CrO4, where the highest efficiency was obtained with 20 ppm of inhibitor. Pitting potential with 5 ppm of inhibitor, regardless its chemical composition, was more active than in absence of inhibitor, increased at 20 ppm, especially with Li2CrO4, and remained unaltered with 50 ppm. EN measurements showed that at 5 ppm of inhibitor, the number of film rupture/repassivation events was higher than that obtained at 20 or 50 ppm. Adsorption isotherms suggested a different adsorption mechanism for each inhibitor, whereas EIS results suggested that the corrosion process when nitrates were added was under charge transfer control, but in the case of molybdates or chromates was under diffusion control

  1. Effect of inorganic inhibitors on the corrosion behavior of 1018 carbon steel in the LiBr + ethylene glycol + H{sub 2}O mixture

    Energy Technology Data Exchange (ETDEWEB)

    Samiento-Bustos, E. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autonoma del Estado de Morelos. Av. Universidad 1001, Col. Chamilpa, CP 62210, Cuernavaca, Morelos (Mexico); Rodriguez, J.G. Gonzalez [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autonoma del Estado de Morelos. Av. Universidad 1001, Col. Chamilpa, CP 62210, Cuernavaca, Morelos (Mexico)], E-mail: ggonzalez@uaem.mx; Uruchurtu, J. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autonoma del Estado de Morelos. Av. Universidad 1001, Col. Chamilpa, CP 62210, Cuernavaca, Morelos (Mexico); Dominguez-Patino, G. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autonoma del Estado de Morelos. Av. Universidad 1001, Col. Chamilpa, CP 62210, Cuernavaca, Morelos (Mexico); U.A.E.M. Facultad de Ciencias Quimicas e Ingenieria, Av. Universidad 1001, 62209, Cuernavaca, Morelos (Mexico); Salinas-Bravo, V.M. [Instituto de Investigaciones Electricas, Gerencia de Materiales y Proceso Quimicos, Av. Reforma 113, Col. Palmira, CP 62490, Cuernavaca, Morelos (Mexico)

    2008-08-15

    The effect of inorganic inhibitors on the corrosion behavior of 1018 carbon steel in the mixture LiBr (55%) + ethylene glycol + H{sub 2}O at room temperature has been evaluated. Used inhibitors included LiNO{sub 3} (Lithium Nitrate), Li{sub 2}MoO{sub 4} (Lithium Molybdate) and Li{sub 2}CrO{sub 4} (Lithium Chromate) at concentrations of 5, 20 and 50 ppm. Electrochemical techniques included potentiodynamic polarization curves, electrochemical noise resistance (EN) and electrochemical impedance spectroscopy (EIS) measurements. Additionally, adsorption isotherms were calculated. The results obtained showed that both, the corrosion rate and the passive current density decreased with inhibitors, and, in general terms, inhibitors efficiency increased with inhibitor concentration, except in the case of Li{sub 2}CrO{sub 4,} where the highest efficiency was obtained with 20 ppm of inhibitor. Pitting potential with 5 ppm of inhibitor, regardless its chemical composition, was more active than in absence of inhibitor, increased at 20 ppm, especially with Li{sub 2}CrO{sub 4}, and remained unaltered with 50 ppm. EN measurements showed that at 5 ppm of inhibitor, the number of film rupture/repassivation events was higher than that obtained at 20 or 50 ppm. Adsorption isotherms suggested a different adsorption mechanism for each inhibitor, whereas EIS results suggested that the corrosion process when nitrates were added was under charge transfer control, but in the case of molybdates or chromates was under diffusion control.

  2. Association constants in solutions of lithium salts in butyrolactone and a mixture of propylene carbonate with 1,2-dimethoxyethane (1 : 1), according to conductometric data

    Science.gov (United States)

    Chernozhuk, T. V.; Sherstyuk, Yu. S.; Novikov, D. O.; Kalugin, O. N.

    2016-02-01

    A conductometric study is performed with solutions of lithium bis(oxalato)borate (LiBOB) in γ-butyrolactone (γ-BL) at 278.15-388.15 K and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), LiBOB, and lithium tetrafluoroborate (LiBF4) in mixtures of propylene carbonate and 1,2-dimethoxyethane (PC + 1,2-DME) (1 : 1) at 278.15-348.15 K. Limiting molar electrical conductivities (LMECs) and association constants ( K a) in the studied solutions of electrolytes are determined using the Lee-Wheaton equation. The effect temperature, the nature of the solvent, and the properties of the anion have on the conductivity and interparticle interactions in solutions of lithium salts in γ-BL and PC + 1,2-DME (1 : 1) is established. It was concluded that the studied solutions are characterized by low values of their association constants. It was found that the BOB;- anion destroys the structure of the solvent.The thickness of the dynamic solvation shell of ions (Δ R) remains constant for both solvents over the studied range of temperatures, and Δ R is significantly greater for Li+ than for other ions.

  3. Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C10H22O5 2,5,8,11,14-Pentaoxapentadecane (VMSD1112, LB4865_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C10H22O5 2,5,8,11,14-Pentaoxapentadecane (VMSD1112, LB4865_V)' providing data by calculation of mass density in the single-phase region(s) from low-pressure dilatometric measurements of the molar excess volume at variable mole fraction and constant temperature.

  4. Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C6H12O3 2,4,6-Trimethyl-1,3,5-trioxane (VMSD1511, LB4517_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C6H12O3 2,4,6-Trimethyl-1,3,5-trioxane (VMSD1511, LB4517_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  5. Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C6H12O3 2,4,6-Trimethyl-1,3,5-trioxane (VMSD1212, LB4519_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C6H12O3 2,4,6-Trimethyl-1,3,5-trioxane (VMSD1212, LB4519_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  6. Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C6H12O3 2,4,6-Trimethyl-1,3,5-trioxane (VMSD1111, LB4518_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C6H12O3 2,4,6-Trimethyl-1,3,5-trioxane (VMSD1111, LB4518_V)' providing data from direct low-pressure measurement of mass density at variable mole fraction and constant temperature, in the single-phase region(s).

  7. Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C10H22O5 2,5,8,11,14-Pentaoxapentadecane (VMSD1211, LB4862_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C10H22O5 2,5,8,11,14-Pentaoxapentadecane (VMSD1211, LB4862_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  8. Dissipation of a commercial mixture of polyoxyethylene amine surfactants in aquatic outdoor microcosms: Effect of water depth and sediment organic carbon.

    Science.gov (United States)

    Rodriguez-Gil, Jose Luis; Lissemore, Linda; Solomon, Keith; Hanson, Mark

    2016-04-15

    This study optimized existing analytical approaches and characterized the effect of sediment total organic carbon (0.05-2.05% TOC), and water depth (15, 30, and 90cm) on the fate of MON 0818, a commercial mixture of polyoxyethylene amine surfactants (POEAs), in outdoor microcosms. Mixtures of POEAs are commonly used as adjuvants in commercial herbicide formulations containing glyphosate. Until recently, analytical methods sensitive enough to monitor environmental concentrations of POEAs in aquatic systems were not available. After optimizing recently developed analytical methods, we found that the combined use of accelerated solvent extraction (ASE) and liquid chromatography-tandem mass spectrometry provided a reliable approach for determining the concentration of sediment-adsorbed POEAs. The surfactant showed strong affinity for sediment materials, with low maximum recoveries by ASE of 52%. Under microcosm conditions, water depth or sediment characteristics did not significantly affect the water-column half-life of POEA, which ranged from 3.2 to 5.3h. Binding of POEAs to suspended solids was observed, which dissipated via one- or two-phase exponential decay; when two-phase decay occurred, fast phase half-life values ranged from 0.71 to 1.3h and slow-phase values ranged from 18 to 44h. Concentrations of POEA increased in sediment shortly after application and decreased over the study period with a half-life of 5.8 to 71d. The concentrations of POEAs in the sediment of the shallow (15cm) ponds dissipated following a two-phase exponential decay model with an initial fast-phase half-life of 1.1 to 8.9d and a slower second-phase half-life of 21d. Our results suggest that aquatic organisms are unlikely to be exposed to POEAs in aqueous phase for periods of more than a few hours following an over-water application, and that sediment is a significant sink for POEAs in aquatic systems. PMID:26845181

  9. Effects of radio-frequency power on the properties of carbon thin films prepared by thermal chemical vapor deposition enhanced with remote inductively-coupled-plasma using acetylene/nitrogen mixtures

    International Nuclear Information System (INIS)

    The effects of radio-frequency (rf) power on the properties of carbon thin films prepared by thermal chemical vapor deposition (CVD) enhanced with remote inductively-coupled-plasma (ICP) are investigated. Acetylene and nitrogen were used as the precursor gases, and rf-powers of ICP were set as 0, 100, 200, 300, and 400 W. The deposition temperature, working pressure, and deposition time were set as 1248 K, 4 kPa, and 2 h, respectively. The residual gases, film thicknesses, microstructures, chemical characteristics, mechanical properties, and electrical properties of carbon thin films were investigated by residual gas analyzer (RGA), field emission scanning electron microscopy, X-ray diffractometer (and Raman scattering spectrometer), X-ray photoelectron spectrometer, nanoindenter, and four point probe, respectively. RGA results reveal that the main species in the gas phase contain H2, C2H, C2H2, HCN (or C2H3), and N2 (or C2H4). Moreover, C2H, C2H2, and C2H4 can be speculated as the main species for carbon thin film deposition. As the rf-power increases from 0 to 400 W, the deposition rate of carbon thin films decreases from 204 to 36.0 nm/h. The crystallinity and ordering degree of carbon thin films increase with increasing rf-power from 0 to 400 W, but the ratio of sp2 carbon sites in carbon thin films decreases from 95 to 75%. The Young's modulus, hardness, and electrical resistivity of carbon thin films increase with increasing rf-power. Furthermore, the effects of rf-power on the deposition rates of carbon thin films prepared by thermal CVD enhanced with remote ICP using C2H2/N2 and CH4/N2 mixtures are compared. - Highlights: • Carbon films are prepared by TCVD enhanced with remote ICP using C2H2/N2 mixtures. • The deposition rate of carbon thin films decreases with increasing the rf-power. • C2H, C2H2, and C2H4 are speculated as the main species for carbon film deposition. • The sp2 sites in carbon thin films decrease with increasing rf-power.

  10. Phase formation during the LnBa2Cu3Ox (Ln = Nd, Eu, Gd, Tb, Ho, Yb) synthesis from the mixture of copper and rare earth oxides with barium carbonate

    International Nuclear Information System (INIS)

    Phase formation during LnBa2Cu3Ox synthesis from a mixture of copper and rare earth oxides with barium carbonate under different synthesis conditions in investigated by the methods of thermal, X-ray phase and X-ray microanalyses. Powder-like and molded pellets were synthesized at 800-1000 deg C with 0.5-18 h isothermal holding under heated furnace-air hardening or slow cooling conditions. To produce LaBa2Cu3Ox monophase samples from oxide-carbonate mixture 950 deg temperature is required for Ln = Nd, Eu, Ho and 980 deg temparature for Ln = Gd with approximatly 4 h holding. In case of Ln = Yb, a multistage annealing is essential, and in case of Tb, the above compound is not formed under the investigated conditions. Temperatures of rhombic-tetragonal transitions are determined for the produced compounds

  11. Spin-orbit effects, VSEPR theory, and the electronic structures of heavy and superheavy group IVA hydrides and group VIIIA tetrafluorides. A partial role reversal for elements 114 and 118

    International Nuclear Information System (INIS)

    Relativistic effective core potentials and spin-orbit operators are used in relativistic configuration interaction calculations to explore the effects of spin-orbit coupling on the electronic structures of atoms and molecules of elements 114 and 118. The monohydrides of group IVA and the tetrafluorides of group VIIIA are examined in order to provide examples of trends within families among the various periods. The spin-orbit effect is found to play a dominant role in the determination of atomic and molecular properties. Several nonintuitive consequences of spin-orbit coupling are presented, including the depiction of element 114 as a closed-shell noble atom and the suggestion that the VSEPR theory in inadequate to describe the geometry of the rare gas tetrafluoride, (118)F4

  12. A Continuous Flow Column Study of the Anaerobic Transformation of a CAH Mixture of Tetrachloroethene and Carbon Tetrachloride Using Formate as an Electron Donor

    Science.gov (United States)

    Semprini, L.; Azizian, M. F.; Kim, Y.

    2011-12-01

    Many groundwater sites are contaminated with mixtures of chlorinated aliphatic hydrocarbons (CAHs) that represent a challenge when biological remediation processes are being considered. This is especially challenging when high concentrations of CAHs are present.Trichloromethane (CF), for example, has been observed to inhibit and potentially exert toxicity on reductive dehalogenation of tetrachloroethene (PCE) and trichloroethene (TCE). Results will be presented from a continuous flow column study where the simultaneous transformation of PCE and carbon tetrachloride (CT) was achieved. The column was packed with a quartz sand and bioaugmented with the Evanite Culture (EV) that is capable of transforming PCE to ethene. The column was fed a synthetic groundwater that was amended with PCE to achieve an influent concentration near its solubility limit (0.10 mM) and formate (1.5 mM) that reacts to produce hydrogen as the ultimate electron donor. The column was operated for over 1600 days prior to the addition of CT. During this period PCE was transformed mainly to vinyl chloride (VC) and ethene (ETH) and minor amounts of cis-dichloroethene (cis-DCE) and TCE. The transformation extent achieved based on the column effluent concentrations ranged from about 50% ETH, 30% VC, and 20 cis-DCE up to 80% ETH and 20% VC. When the column was fed sulfate, it was completely transformed via sulfate reduction. Ferrous iron production from ferric iron reduction was observed early in the study. Acetate was also formed as a result of homoacetogenesis from hydrogen utilization. CT addition (0.015 mM) was started at 1600 days while PCE addition was continued. During the first 25 days of CT addition, CT concentrations gradually increased to 50% of the injection concentration and chloromethane (CM) and CF were observed as transformation products. CT concentrations then decreased with over 98% transformation achieved.CM was removed to below the detection limit and CF concentration decreases to

  13. Applications of the Simple Multi-Fluid Model to Correlations of the Vapor-Liquid Equilibrium of Refrigerant Mixtures Containing Carbon Dioxide

    Science.gov (United States)

    Akasaka, Ryo

    This study presents a simple multi-fluid model for Helmholtz energy equations of state. The model contains only three parameters, whereas rigorous multi-fluid models developed for several industrially important mixtures usually have more than 10 parameters and coefficients. Therefore, the model can be applied to mixtures where experimental data is limited. Vapor-liquid equilibrium (VLE) of the following seven mixtures have been successfully correlated with the model: CO2 + difluoromethane (R-32), CO2 + trifluoromethane (R-23), CO2 + fluoromethane (R-41), CO2 + 1,1,1,2- tetrafluoroethane (R-134a), CO2 + pentafluoroethane (R-125), CO2 + 1,1-difluoroethane (R-152a), and CO2 + dimethyl ether (DME). The best currently available equations of state for the pure refrigerants were used for the correlations. For all mixtures, average deviations in calculated bubble-point pressures from experimental values are within 2%. The simple multi-fluid model will be helpful for design and simulations of heat pumps and refrigeration systems using the mixtures as working fluid.

  14. Characterization of coal- and petroleum-derived binder pitches and the interaction of pitch/coke mixtures in pre-baked carbon anodes

    Science.gov (United States)

    Suriyapraphadilok, Uthaiporn

    Carbon anodes are manufactured from calcined petroleum coke (i.e. sponge coke) and recycled anode butts as fillers, and coal tar pitch (SCTP) as the binder. During the manufacturing of carbon anodes, coal tar pitch is mixed with calcined petroleum coke. The mix of binder, filler and some additives is heated to about 50°C above the softening point of the pitch, typically 160°C. This temperature is sufficient to enable the pitch to wet the coke particles. The mix is then either extruded, vibrated, or pressed to form a green anode. The binding between coke and pitch is very important to the anode properties. There are different binder pitches used in this work, which were standard coal tar pitch (SCTP-2), petroleum pitch (PP-1), gasification pitch (GP-115), coal-extract pitch (WVU-5), and co-coking pitches (HTCCP and OXCCP). Petroleum pitch is a residue produced from heat-treatment and distillation of petroleum fractions. Production of coal-extract pitch involves a prehydrogenation of coal followed by extraction using a dipolar solvent. Gasification pitches are distilled by-product tars produced from the coal gasification process. Co-coking pitch was developed in this work and was obtained from the liquid distillate of co-coking process of coal and heavy petroleum residue. Understanding of composition and structures of pitches from different sources and processes would lead to greater understanding of the binding properties of pitch in carbon anodes and was one of the main focuses in this study. Characterization of pitches by using different techniques including gas chromatography/mass spectrometry (GC/MS), high performance liquid chromatography (HPLC), matrix-assisted laser desorption ionization/mass spectrometry (MALDI/MS), 1H and 13C solution-state nuclear magnetic resonance (NMR), and 13C solid-state NMR yield important chemistry and structural information. The binding, or in other words the interactions in the pitch/coke mixture, is another interest in this

  15. 短切PAN基碳纤维导电沥青混合料性能试验研究%Experimental research on performances for conductive asphalt mixture with chopped PAN-based carbon fiber

    Institute of Scientific and Technical Information of China (English)

    查旭东; 陈勇强; 程景

    2012-01-01

    In order to determine a reasonable carbon fiber contents for the conductive asphalt mixture with carbon fiber,the chopped polyacrylonitrile(PAN) based carbon fiber was selected as a conductive phase material.Many laboratory experiments were conducted to analyze the effect of the carbon fiber contents on the Marshall performances and the conductive performances for the AC-13C of conductive asphalt mixture and then verify its pavement performances.The results show that,under the same asphalt-aggregate ratio,with the increases of the carbon fiber contents,the bulk volume density,the voids filled with asphalt and the Marshall stability of the conductive asphalt mixture are appeared the trend from increasing to decreasing,the volume of air voids and the voids in mineral aggregate are changed as the relation from decreasing to increasing,but the flow value is increased continuously.The technical standards of AC,adjustment and SMA were applied to the asphalt mixtures with the different ranges of carbon fiber content,respectively,and the reasonable optimal asphalt-aggregate ratios were determined.There is a good semilogarithm correlation between the optimal asphalt-aggregate ratios and the carbon fiber contents.Under the optimal asphalt-aggregate ratio,a good correlation of power function is showed between the logarithms of electrical resistivity and the carbon fiber contents for the conductive asphalt mixture.All the pavement performances of asphalt mixture with 0.1% of carbon fiber content have attained the technical requirements of modified asphalt mixture and SMA in the climate conditions with high demand.Therefore,the suitable carbon fiber content can play an excellent role in reinforcing the conductive asphalt mixture and then form the stable conductive network.The technical requirements of various performances and conductive heating are integrated to recommend the suitable carbon fiber content as 0.1%.%为了确定碳纤维导电沥青混合料的合理碳纤

  16. Effects of radio-frequency power on the properties of carbon thin films prepared by thermal chemical vapor deposition enhanced with remote inductively-coupled-plasma using acetylene/nitrogen mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Liang-Hsun; Wu, Kuan-Chang; Shiue, Sham-Tsong, E-mail: stshiue@dragon.nchu.edu.tw

    2014-11-03

    The effects of radio-frequency (rf) power on the properties of carbon thin films prepared by thermal chemical vapor deposition (CVD) enhanced with remote inductively-coupled-plasma (ICP) are investigated. Acetylene and nitrogen were used as the precursor gases, and rf-powers of ICP were set as 0, 100, 200, 300, and 400 W. The deposition temperature, working pressure, and deposition time were set as 1248 K, 4 kPa, and 2 h, respectively. The residual gases, film thicknesses, microstructures, chemical characteristics, mechanical properties, and electrical properties of carbon thin films were investigated by residual gas analyzer (RGA), field emission scanning electron microscopy, X-ray diffractometer (and Raman scattering spectrometer), X-ray photoelectron spectrometer, nanoindenter, and four point probe, respectively. RGA results reveal that the main species in the gas phase contain H{sub 2}, C{sub 2}H, C{sub 2}H{sub 2}, HCN (or C{sub 2}H{sub 3}), and N{sub 2} (or C{sub 2}H{sub 4}). Moreover, C{sub 2}H, C{sub 2}H{sub 2}, and C{sub 2}H{sub 4} can be speculated as the main species for carbon thin film deposition. As the rf-power increases from 0 to 400 W, the deposition rate of carbon thin films decreases from 204 to 36.0 nm/h. The crystallinity and ordering degree of carbon thin films increase with increasing rf-power from 0 to 400 W, but the ratio of sp{sup 2} carbon sites in carbon thin films decreases from 95 to 75%. The Young's modulus, hardness, and electrical resistivity of carbon thin films increase with increasing rf-power. Furthermore, the effects of rf-power on the deposition rates of carbon thin films prepared by thermal CVD enhanced with remote ICP using C{sub 2}H{sub 2}/N{sub 2} and CH{sub 4}/N{sub 2} mixtures are compared. - Highlights: • Carbon films are prepared by TCVD enhanced with remote ICP using C{sub 2}H{sub 2}/N{sub 2} mixtures. • The deposition rate of carbon thin films decreases with increasing the rf-power. • C{sub 2}H, C{sub 2}H

  17. Viscosity of LiF–NaF–KF eutectic and effect of cerium trifluoride and uranium tetrafluoride additions

    International Nuclear Information System (INIS)

    Highlights: • Kinematic viscosity of the 46.5LiF–11.5NaF–42KF eutectic (mol%) is measured. • Method of torsional oscillations damping of a cylinder filled with the melt is used. • Found that the kinematic viscosity of this eutectic has some deviations from the exponential law, that may be explained by the existence of clusters in the melt. • Addition of CeF3 or UF4 significantly increased the liquidus temperature of eutectic. • Addition of CeF3 and UF4 decreased the viscosity of the eutectic at low temperatures. - Abstract: Kinematic viscosity of the 46.5LiF–11.5NaF–42KF eutectic (mol%) has been measured in the temperature range 727–1144 K by the method of torsional oscillations damping of a cylinder with the liquid under study. Found that the kinematic viscosity of this eutectic has some deviations from the exponential law, that may be explained by the existence of clusters in the melt. The volume fraction of the clusters in the eutectic as a function of its temperature was estimated. The kinematic viscosity of the 46.5LiF–11.5NaF–42KF eutectic (in mol%) with additions of (1) 5 and 10 mol% CeF3 as well as (2) 20 mol% UF4 and 10 mol% CeF3 was also measured. It is experimentally proved that the addition of 5 mol% CeF3 significantly reduces the viscosity at low temperatures and slightly increases it – at high temperatures. Reduction of viscosity at low temperatures can be explained by the fact that the molecules of CeF3 destroy clusters. Additions of 20 mol% UF4 also decreased kinematic viscosity of the molten salt mixture compared to pure 46.5LiF–11.5NaF–42KF eutectic (in mol%). Note, that all additions used significantly increased the liquidus temperature of the molten salt mixture. Particularly, additions of 20 mol% UF4 without and with 10 mol% CeF3 increased the liquidus temperature up to 923 and 1023 K, respectively

  18. Viscosity of LiF–NaF–KF eutectic and effect of cerium trifluoride and uranium tetrafluoride additions

    Energy Technology Data Exchange (ETDEWEB)

    Merzlyakov, Alexander; Ignatiev, Victor, E-mail: Ignatev_VV@nrcki.ru; Abalin, Sergei

    2014-10-15

    Highlights: • Kinematic viscosity of the 46.5LiF–11.5NaF–42KF eutectic (mol%) is measured. • Method of torsional oscillations damping of a cylinder filled with the melt is used. • Found that the kinematic viscosity of this eutectic has some deviations from the exponential law, that may be explained by the existence of clusters in the melt. • Addition of CeF{sub 3} or UF{sub 4} significantly increased the liquidus temperature of eutectic. • Addition of CeF{sub 3} and UF{sub 4} decreased the viscosity of the eutectic at low temperatures. - Abstract: Kinematic viscosity of the 46.5LiF–11.5NaF–42KF eutectic (mol%) has been measured in the temperature range 727–1144 K by the method of torsional oscillations damping of a cylinder with the liquid under study. Found that the kinematic viscosity of this eutectic has some deviations from the exponential law, that may be explained by the existence of clusters in the melt. The volume fraction of the clusters in the eutectic as a function of its temperature was estimated. The kinematic viscosity of the 46.5LiF–11.5NaF–42KF eutectic (in mol%) with additions of (1) 5 and 10 mol% CeF{sub 3} as well as (2) 20 mol% UF{sub 4} and 10 mol% CeF{sub 3} was also measured. It is experimentally proved that the addition of 5 mol% CeF{sub 3} significantly reduces the viscosity at low temperatures and slightly increases it – at high temperatures. Reduction of viscosity at low temperatures can be explained by the fact that the molecules of CeF{sub 3} destroy clusters. Additions of 20 mol% UF{sub 4} also decreased kinematic viscosity of the molten salt mixture compared to pure 46.5LiF–11.5NaF–42KF eutectic (in mol%). Note, that all additions used significantly increased the liquidus temperature of the molten salt mixture. Particularly, additions of 20 mol% UF{sub 4} without and with 10 mol% CeF{sub 3} increased the liquidus temperature up to 923 and 1023 K, respectively.

  19. Prediction of the critical reduced electric field strength for carbon dioxide and its mixtures with 50% O2 and 50% H2 from Boltzmann analysis for gas temperatures up to 3500 K at atmospheric pressure

    Science.gov (United States)

    Zhao, Hu; Li, Xingwen; Jia, Shenli; Murphy, Anthony B.

    2014-08-01

    This paper provides theoretical calculations that predict the dielectric breakdown properties of carbon dioxide (CO2) and its mixtures with 50% O2 and 50% H2 for a gas temperature range of 300-3500 K at 0.1 MPa. CO2 is one of the most likely candidates for an environment-friendly arc-quenching medium to replace SF6 in high-voltage circuit breakers. Initially, the electron energy distribution function (EEDF) is derived by solving the Boltzmann equation under the zero-dimensional two-term spherical harmonic approximation. Then the reduced ionization and attachment coefficients are obtained, based on the calculated EEDF. Finally, the critical reduced electric field strength (E/N)cr, which is defined as the value for which total ionization reactions are equal to total attachment reactions, is obtained and analysed. The results demonstrate the superior breakdown properties of a 50% CO2-50% O2 mixture to those of both pure CO2 and 50% CO2-50% H2. Nearly no deviation in (E/N)cr is found in a 50% CO2-50% O2 mixture for gas temperatures up to 2500 K, and although there is clear reduction as the gas temperature is increased further to 3500 K, the value remains higher than that of pure CO2.

  20. Performance experiments of carbon fiber-reinforced conductive SBS modified asphalt mixture%碳纤维导电SBS改性沥青混合料性能试验

    Institute of Scientific and Technical Information of China (English)

    查旭东; 蔡良; 曹艳霞

    2014-01-01

    In order to analyze pavement performances and ice-melting effects of conductive asphalt concrete,the chopped polyacrylonitrile-based carbon fibers were incorporated into SBS modified asphalt mixture AC-13C to prepare the carbon fiber-reinforced conductive modified asphalt mixtures.Five kinds of carbon fiber contents were selected respectively to conduct the laboratory experiments such as mix ratio design,pavement performances and simulated ice-melting etc.The results show,with the increase of carbon fiber content,the optimum asphalt-aggregate ratios of SBS modified asphalt mixture increase linearly;the dy-namic stability,the immersion residual Marshall stability and the freeze-thaw split strength ratios change in parabolic relationship;the low-temperature flexural-tensile strengths and the failure strains increase in"S"curve,but the stiffness moduli decrease in"Z"curve.It il-lustrates when the proper carbon fibers were incorporated into the SBS modified asphalt mixture,the pavement performances such as high-temperature anti-rutting,low-tempera-ture anti-cracking and moisture damage resistance etc can be improved because of the bridg-ing,reinforced and toughening effects of carbon fiber.However,the excessive carbon fibers can cause the decrease of enhancement effect because of poor dispersion and easy cluster. Simultaneously,when the carbon fiber contents are more than 0.3%,the carbon fibers in-side mixtures are lapped each other to form the good conductive network with the fine ice-melting results.On the whole,when the carbon fiber content is 0.4%,the pavement per-formances,the electrical conductivity and the ice-melting efficiency of carbon fiber-rein-forced SBS modified asphalt mixture are the best.%为了分析导电沥青混凝土的路用性能和融冰效果,将短切聚丙烯腈基碳纤维掺入 SBS改性沥青混合料 AC-13 C中,制备成碳纤维导电改性沥青混合料。选取5种碳纤维掺量分别进行了配合比设计、路用性能和模拟

  1. Suppression of hydrogenated carbon film deposition and hydrogen isotope retention by nitrogen addition into cold remote H/D and CH4 mixture plasmas

    International Nuclear Information System (INIS)

    Control of tritium retention and its removal from the first wall of future fusion devices are one of the most crucial issues for safety and effective use for fuel. Nitrogen addition into remote edge plasmas has been considered and tested as an effective method for suppression of carbon film deposition and reduction of hydrogen isotope absorption in the deposited films. In this paper we have investigated the scavenger effects of nitrogen injected into low temperature D2/CH4 plasmas on hydrogenated carbon film growth using a small helical device. The result of the deposition shows that the key reactive particles with CN and ND(H) bonds to suppression of hydrogenated carbon film growth and hydrogen isotope absorption are much slowly generated compared with hydrocarbon particles such as CD(H)x and C2D(H)x. This may be due to the slow atomic nitrogen diffusion into hydrogenated carbon layer and the chemical equilibrium between nitrogen absorption

  2. Suppression of hydrogenated carbon film deposition and hydrogen isotope retention by nitrogen addition into cold remote H/D and CH4 mixture plasmas

    Science.gov (United States)

    Iida, K.; Notani, M.; Uesugi, Y.; Tanaka, Y.; Ishijima, T.

    2015-08-01

    Control of tritium retention and its removal from the first wall of future fusion devices are one of the most crucial issues for safety and effective use for fuel. Nitrogen addition into remote edge plasmas has been considered and tested as an effective method for suppression of carbon film deposition and reduction of hydrogen isotope absorption in the deposited films. In this paper we have investigated the scavenger effects of nitrogen injected into low temperature D2/CH4 plasmas on hydrogenated carbon film growth using a small helical device. The result of the deposition shows that the key reactive particles with CN and ND(H) bonds to suppression of hydrogenated carbon film growth and hydrogen isotope absorption are much slowly generated compared with hydrocarbon particles such as CD(H)x and C2D(H)x. This may be due to the slow atomic nitrogen diffusion into hydrogenated carbon layer and the chemical equilibrium between nitrogen absorption.

  3. Mixture Density Mercer Kernels

    Data.gov (United States)

    National Aeronautics and Space Administration — We present a method of generating Mercer Kernels from an ensemble of probabilistic mixture models, where each mixture model is generated from a Bayesian mixture...

  4. Carbon deposition from a γ-irradiated CO2/CO/CH4/C2H6 gas mixture on magnetite Fe3O4

    International Nuclear Information System (INIS)

    Previous studies have indicated that carbon is deposited on spinel-type oxides containing manganese, iron, nickel and chromium manganese oxides and uranium oxides, especially where rapid electron exchange is possible in mixed valence compounds. In this investigation, characterised magnetite. Fe3O4, surfaces have been subjected to γ-irradiation under conditions of temperature, pressure and atmosphere similar to those experienced in reactor with the aim of furthering our understanding of the catalytic processes involved in deposit initiation and growth. Although it was not possible to produce large (111) Fe3O4 planes, enhanced carbon deposition was observed on small (111) regions showing the enhanced catalytic effect of these planes for carbon deposition out of the gas phase. (orig.)

  5. 石墨烯/碳纳米管复合粉体制备工艺的研究%Research on Preparation Process of Graphene Platelets/Carbon Nanotube Mixture Powders

    Institute of Scientific and Technical Information of China (English)

    易义武; 曾效舒; 罗超

    2011-01-01

    It has been explored for synthesizing in situ mixture powder of graphene platelet (NGP) and carbon nanotube(CNT) using expanded graphite(EG) as the catalyst support through CVD technology. The structures of the mixture powder were characterized by SEM. The results showed that it was easy to produce in mass the mixture powder using general CVD. The graphene platelets in this mixture powder were plane structure and only l0nm thick. The ratio of the CNT/NGP, which generally ranged from 0. 625 to 8. 250, could be adjusted through adjusting deposition parameters. And the optimal catalyst and optimal process have been acquired roughly. Research conclusion show that the excellent performance of NGP/CNT mixture powder materials can be prepared by this method.%研究了利用膨化石墨制备石墨烯/碳纳米管复合粉体技术.以膨胀石墨为基体,利用硝酸铁、碳酸铵等对其进行修饰,结合化学气相沉积工艺,原位制备出石墨烯/碳纳米管复合粉体材料;研究了不同的修饰液相、不同沉积工艺对复合粉体比例、微观形貌的影响.利用扫描电镜对复合粉体进行了表征.结果表明,实现了石墨烯/碳纳米管复合粉体材料的批量制备;其中石墨烯为透明薄片,其厚度最小可达到10nm;通过控制工艺参数,可以实现碳纳米管/石墨烯的质量比在0.625~8.250之间变化;并初步获得了最佳修饰液相和最佳工艺.研究结果表明该方法可以制备出性能优异的石墨烯/碳纳米管复合粉体材料.

  6. SiC Nanowires Synthesized by Rapidly Heating a Mixture of SiO and Arc-Discharge Plasma Pretreated Carbon Black

    Directory of Open Access Journals (Sweden)

    Wang Feng-Lei

    2008-01-01

    Full Text Available Abstract SiC nanowires have been synthesized at 1,600 °C by using a simple and low-cost method in a high-frequency induction furnace. The commercial SiO powder and the arc-discharge plasma pretreated carbon black were mixed and used as the source materials. The heating-up and reaction time is less than half an hour. It was found that most of the nanowires have core-shell SiC/SiO2nanostructures. The nucleation, precipitation, and growth processes were discussed in terms of the oxide-assisted cluster-solid mechanism.

  7. Carbon particles

    Science.gov (United States)

    Hunt, Arlon J.

    1984-01-01

    A method and apparatus whereby small carbon particles are made by pyrolysis of a mixture of acetylene carried in argon. The mixture is injected through a nozzle into a heated tube. A small amount of air is added to the mixture. In order to prevent carbon build-up at the nozzle, the nozzle tip is externally cooled. The tube is also elongated sufficiently to assure efficient pyrolysis at the desired flow rates. A key feature of the method is that the acetylene and argon, for example, are premixed in a dilute ratio, and such mixture is injected while cool to minimize the agglomeration of the particles, which produces carbon particles with desired optical properties for use as a solar radiant heat absorber.

  8. Optimal mixture experiments

    CERN Document Server

    Sinha, B K; Pal, Manisha; Das, P

    2014-01-01

    The book dwells mainly on the optimality aspects of mixture designs. As mixture models are a special case of regression models, a general discussion on regression designs has been presented, which includes topics like continuous designs, de la Garza phenomenon, Loewner order domination, Equivalence theorems for different optimality criteria and standard optimality results for single variable polynomial regression and multivariate linear and quadratic regression models. This is followed by a review of the available literature on estimation of parameters in mixture models. Based on recent research findings, the volume also introduces optimal mixture designs for estimation of optimum mixing proportions in different mixture models, which include Scheffé’s quadratic model, Darroch-Waller model, log- contrast model, mixture-amount models, random coefficient models and multi-response model.  Robust mixture designs and mixture designs in blocks have been also reviewed. Moreover, some applications of mixture desig...

  9. Electroanalysis with carbon paste electrodes

    CERN Document Server

    Svancara, Ivan; Walcarius, Alain; Vytras, Karel

    2011-01-01

    Introduction to Electrochemistry and Electroanalysis with Carbon Paste-Based ElectrodesHistorical Survey and GlossaryField in Publication Activities and LiteratureCarbon Pastes and Carbon Paste ElectrodesCarbon Paste as the Binary MixtureClassification of Carbon Pastes and Carbon Paste ElectrodesConstruction of Carbon Paste HoldersCarbon Paste as the Electrode MaterialPhysicochemical Properties of Carbon PastesElectrochemical Characteristics of Carbon PastesTesting of Unmodified CPEsIntera

  10. Diamond-like-carbon nanoparticle production and agglomeration following UV multi-photon excitation of static naphthalene/helium gas mixtures

    Science.gov (United States)

    Walsh, A. J.; Tielens, A. G. G. M.; Ruth, A. A.

    2016-07-01

    We report the formation of nanoparticles with significant diamond character after UV multi-photon laser excitation of gaseous naphthalene, buffered in static helium gas, at room temperature. The nanoparticles are identified in situ by their absorption and scattering spectra between 400 and 850 nm, which are modeled using Mie theory. Comparisons of the particles' spectroscopic and optical properties with those of carbonaceous materials indicate a sp3/sp2 hybridization ratio of 8:1 of the particles formed. The particle extinction in the closed static (unstirred) gas-phase system exhibits a complex and quasi-oscillatory time dependence for the duration of up to several hours with periods ranging from seconds to many minutes. The extinction dynamics of the system is based on a combination of transport features and particle interaction, predominantly agglomeration. The relatively long period of agglomeration allows for a unique analysis of the agglomeration process of diamond-like carbon nanoparticles in situ.

  11. Optimized unlike-pair interactions for water-carbon dioxide mixtures described by the SPC/E and EPM2 models.

    Science.gov (United States)

    Vlcek, Lukas; Chialvo, Ariel A; Cole, David R

    2011-07-14

    The unlike-pair interaction parameters for the SPC/E-EPM2 models have been optimized to reproduce the mutual solubility of water and carbon dioxide at the conditions of liquid-supercritical fluid phase equilibria. An efficient global optimization of the parameters is achieved through an implementation of the coupling parameter approach, adapted to phase equilibria calculations in the Gibbs ensemble, that explicitly corrects for the overpolarization of the SPC/E water molecule in the nonpolar CO(2) environments. The resulting H(2)O-CO(2) force field accurately reproduces the available experimental solubilities at the two fluid phases in equilibria as well as the corresponding species tracer diffusion coefficients. PMID:21644504

  12. Low temperature asphalt mixtures

    OpenAIRE

    Modrijan, Damjan

    2006-01-01

    This thesis presents the problem of manufacturing and building in the asphalt mixtures produced by the classical hot procedure and the possibility of manufacturing low temperature asphalt mixtures.We will see the main advantages of low temperature asphalt mixtures prepared with bitumen with organic addition Sasobit and compare it to the classical asphalt mixtures. The advantages and disadvantages of that are valued in the practical example in the conclusion.

  13. Purging mixture for extruder

    OpenAIRE

    Okpala, Chukwubuike

    2015-01-01

    This thesis work focuses on compounding a mechanical purge mixture for extruders. The base resin for making the purge mixture is recycled High Density Polyethylene chosen for its high density and good processing temperature. The additives are mainly clay and sili-con dioxide added as filler and scrubbing materials respectively. The purge mixture was produced by mixing the base resin and additives in percentage ratios into five places la-beled A, B, C, D, and E. the mixtures were extruded and ...

  14. Effect of activated carbon or biochars on toxicity of different soils contaminated by mixture of native polycyclic aromatic hydrocarbons and heavy metals.

    Science.gov (United States)

    Kołtowski, Michał; Oleszczuk, Patryk

    2016-05-01

    Activated carbon (AC), biochar from wheat straw (BCS), and biochar from willow (BCW) were added to the soils sampled from areas of strong anthropogenic influence at doses of 0.5%, 1%, 2.5%, or 5% (w/w) and incubated for 2 mo. At the end of this period, the toxicity of the soils was measured. The effect of AC and biochars on the toxicity of the soils varied based on soil, type of amendment, dose, and test organism. For most of the parameters tested, the highest effectiveness of AC in terms of reduction of toxicity was observed in soil POPI (from bitumen processing plant area). In the case of the remaining soils, after the addition of AC varied results were observed, in which a reduction or an increase of toxicity, relative to the control soil, occurred. As in the case of AC, biochars also caused a significant reduction of phytotoxicity of soil POPI. In soils KB (from coking plant area, industrial waste deposit) and KOK (from coking plant area, coking battery), the reduction or increase of toxicity depended on biochar dose. Compared with the biochars, the effectiveness of AC in the reduction of toxicity depended also on soil, type of amendment, dose, and test organism. Generally, the AC was more effective than biochars in relation to mortality and reproduction of Folsomia candida (in all soils) and for reduction of luminescence inhibition of Vibrio fischeri (in POPI soil). Environ Toxicol Chem 2016;35:1321-1328. © 2015 SETAC. PMID:26378767

  15. Occupational exposure to complex mixtures of volatile organic compounds in ambient air: desorption from activated charcoal using accelerated solvent extraction can replace carbon disulfide?

    Science.gov (United States)

    Fabrizi, Giovanni; Fioretti, Marzia; Rocca, Lucia Mainero

    2013-01-01

    A desorption study of 57 volatile organic compounds (VOCs) has been conducted by use of accelerated solvent extraction (ASE) and gas chromatography-mass spectrometry. Different solvents were tested to extract activated charcoal tubes with the objective of replacing carbon disulfide, used in official methods, because of its highly toxic health and environmental effects. Extraction conditions, for example temperature and number of cycles, were investigated and optimized. The definitive extraction procedure selected was use of acetone at 150 °C and two consecutive extraction cycles at a pressure of 1,500 psi. Considering a sample volume of 0.005 Nm(3), corresponding to a sampling time of 8 h at a flow rate of 0.01 L min(-1), the method was validated over the concentration range 65-26,300 μg Nm(-3). The lowest limit of quantification was 6 μg Nm(-3), and recovery for the 93 % of analytes ranged from 65 to 102 %. For most of the compounds, relative standard deviations were less than 15 % for inter and intra-day precision. Uncertainty of measurement was also determined: the relative expanded uncertainty was always below 29.6 %, except for dichlorodifluoromethane. This work shows that use of friendlier solvent, for example acetone, coupled with use of ASE, can replace use of CS(2) for chemical removal of VOCs from activated charcoal. ASE has several advantages over traditional solvent-extraction methods, including shorter extraction time, minimum sample manipulation, high reproducibility, and less extraction discrimination. No loss of sensitivity occurs and there is also a salutary effect on bench workers' health and on the smell of laboratory air. PMID:22968683

  16. Liquids and liquid mixtures

    CERN Document Server

    Rowlinson, J S; Baldwin, J E; Buckingham, A D; Danishefsky, S

    2013-01-01

    Liquids and Liquid Mixtures, Third Edition explores the equilibrium properties of liquids and liquid mixtures and relates them to the properties of the constituent molecules using the methods of statistical thermodynamics. Topics covered include the critical state, fluid mixtures at high pressures, and the statistical thermodynamics of fluids and mixtures. This book consists of eight chapters and begins with an overview of the liquid state and the thermodynamic properties of liquids and liquid mixtures, including vapor pressure and heat capacities. The discussion then turns to the thermodynami

  17. Iterative Mixture Component Pruning Algorithm for Gaussian Mixture PHD Filter

    OpenAIRE

    Xiaoxi Yan

    2014-01-01

    As far as the increasing number of mixture components in the Gaussian mixture PHD filter is concerned, an iterative mixture component pruning algorithm is proposed. The pruning algorithm is based on maximizing the posterior probability density of the mixture weights. The entropy distribution of the mixture weights is adopted as the prior distribution of mixture component parameters. The iterative update formulations of the mixture weights are derived by Lagrange multiplier and Lambert W funct...

  18. Thermal Properties of Asphalt Mixtures Modified with Conductive Fillers

    OpenAIRE

    Byong Chol Bai; Dae-Wook Park; Hai Viet Vo; Samer Dessouky; Ji Sun Im

    2015-01-01

    This paper investigates the thermal properties of asphalt mixtures modified with conductive fillers used for snow melting and solar harvesting pavements. Two different mixing processes were adopted to mold asphalt mixtures, dry- and wet-mixing, and two conductive fillers were used in this study, graphite and carbon black. The thermal conductivity was compared to investigate the effects of asphalt mixture preparing methods, the quantity, and the distribution of conductive filler on thermal pro...

  19. Study of volumetric properties (PVT) of mixtures made of light hydrocarbons (C1-C4), carbon dioxide and hydrogen sulfide - Experimental measurements through a vibrating tube densimeter and modelling; Etude des proprietes volumetriques (PVT) d'hydrocarbures legers (C1-C4), du dioxyde de carbone et de l'hydrogene sulfure. Mesures par densimetrie a tube vibrant et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Rivollet, F.

    2005-12-15

    Various pollutant contents (i.e. carbon dioxide, hydrogen sulphide or other sulphur products) are found in produced oils. These latter must undergo a number of transformations and purifications. The design and dimensioning of the corresponding units can well be optimized only if one has reliable and accurate data about phase equilibria and volumetric properties and of course reliable and accurate modeling. This work was devoted partly to measurements of volumetric properties on three binary mixtures (ethane - hydrogen sulphide, ethane - propane and carbon dioxide - hydrogen sulphide). These measurements were carried out using equipment, comprising a vibrating tube densimeter (Paar, model DMA 512 P), which was especially designed and built for this work. The binary mixtures were studied in the 253 to 363 K temperature range from at pressures up to either 20 or 40 MPa. Two calibration methods of the vibrating tube were used: the FPMC method (Forced Path Mechanical Calibration) described in the literature and an original method containing neural network, developed herein. The study undertaken about the modeling of volumetric properties made it possible to highlight the inadequacy of the traditional use of cubic equations of state to represent simultaneously volumetric properties and phase equilibria. Among the equations of state investigated, a close attention however was paid to cubic equations of state because of their very great use in the oil field. A new tool was found to adapt cubic equations of state to the simultaneous and satisfactory representation of volumetric properties and phase equilibria. It concerns the coupling of the cubic Redlich-Kwong-Soave equation of state with volume correction through a neural network. This new model was tested successfully, it makes it possible to benefit from the existing work of representation of phase equilibria (mixing rules and interaction coefficients) while improving calculation of the volumetric data.

  20. I. Cognitive and instructional factors relating to students' development of personal models of chemical systems in the general chemistry laboratory II. Solvation in supercritical carbon dioxide/ethanol mixtures studied by molecular dynamics simulation

    Science.gov (United States)

    Anthony, Seth

    likely to appear in students' post-laboratory refined models. These discussions during the laboratory period are primarily prompted by factors external to the students or their laboratory groups such as questions posed by the instructor or laboratory materials. Part II. Solvation of polar molecules within non-polar supercritical carbon dioxide is often facilitated by the introduction of polar cosolvents as entrainers, which are believed to preferentially surround solute molecules. Molecular dynamics simulations of supercritical carbon dioxide/ethanol mixtures reveal that ethanol molecules form hydrogen-bonded aggregates of varying sizes and structures, with cyclic tetramers and pentamers being unusually prevalent. The dynamics of ethanol molecules within these mixtures at a range of thermodynamic conditions can largely be explained by differences in size and structure in these aggregates. Simulations that include solute molecules reveal enhancement of the polar cosolvent around hydrogen-bonding sites on the solute molecules, corroborating and helping to explain previously reported experimental trends in solute mobility.

  1. Preparation of hydrogenated diamond-like carbon films using high-density pulsed plasmas of Ar/C2H2 and Ne/C2H2 mixture

    Science.gov (United States)

    Kimura, Takashi; Kamata, Hikaru

    2016-07-01

    Hydrogenated diamond-like carbon films are prepared using reactive high-density pulsed plasmas of Ar/C2H2 and Ne/C2H2 mixture in the total pressure range from 0.5 to 2 Pa. The plasmas are produced using a reactive high-power impulse magnetron sputtering (HiPIMS) system. A negative pulse voltage of ‑500 V is applied to the substrate for a period of 15 µs in the afterglow mode. The growth rate does not strongly depend on the type of ambient gas but it markedly increases to about 2.7 µm/h at a C2H2 fraction of 10% and a total pressure of 2 Pa with increasing C2H2 fraction. The marked increase in the growth rate means that the HiPIMS system can be regarded as a plasma source for the chemical vapor deposition process. The hardness of the films prepared by Ne/C2H2 plasmas is somewhat higher than that of the films prepared by Ar/C2H2 plasmas under the same operating conditions, and the difference becomes larger as the pressure increases. The hardness of the films prepared by Ne/C2H2 plasmas ranges between 11 and 18 GPa. In the Raman spectra, two very broad overlapping bands are assigned as the G (graphite) and D (disorder) bands. The peak position of the G band is roughly independent of the total pressure, whereas the FWHM of the G peak decreases with increasing total pressure as a whole.

  2. The different types of dielectric barrier discharge in gas mixtures

    International Nuclear Information System (INIS)

    In this paper results of electrical and optical diagnostics of dielectric barrier discharges operating in different gas mixtures are presented. Discharges burning in pure nitrogen, in mixtures of nitrogen and argon, nitrogen and carbon dioxide, nitrogen and 1.3-butadiene, argon and 1.3-butadiene, argon and carbon dioxide were studied. The investigations were focused on the influence of different admixtures and on the finding of the conditions for the generation of diffuse dielectric barrier discharges (Authors)

  3. Mechanics of mixtures

    CERN Document Server

    Rajagopal, KR

    1995-01-01

    This book presents a unified treatment of the mechanics of mixtures of several constituents within the context of continuum mechanics. After an introduction to the basic theory in the first few chapters, the book deals with a detailed exposition of the mechanics of a mixture of a fluid and an elastic solid, which is either isotropic or anisotropic and is capable of undergoing large deformations. Issues regarding the specification of boundary conditions for mixtures are discussed in detail and several boundary value and initial-boundary value problems are solved. The status of some special theo

  4. Solvatochromic Study on Binary Solvent Mixtures with Ionic Liquids

    Science.gov (United States)

    Koel, Mihkel

    2008-08-01

    Solvent effects on 2,6-dichloro-4-(2,4,6-triphenyl-pyridinium-1-yl)phenolate [ET (33) dye] and 7- diethylamino-3,4-benzophenoxazine-2-one (Nile Red) in binary mixtures of organic solvents (acetone, acetonitrile, propylene carbonate, methanol and ethane-1,2-diol) with 1,3-dialkyl imidazoliumbased ionic liquids were studied by UV-visible spectroscopy. Highly nonlinear behaviour of mixtures of alcohols and ionic liquids was found. A preferential solvation model was applied to the data obtained on solvatochromic shifts over the entire mixing range. It is fitting the data well for alcohol mixtures and for other solvent mixtures with different ionic liquids.

  5. Experimental determination and modeling of the phase behavior for the direct synthesis of dimethyl carbonate from methanol and carbon dioxide

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Musko, Nikolai E.; Baiker, Alfons;

    2013-01-01

    This study focuses on the investigation of the phase behavior of mixtures relevant to the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. The bubble points of corresponding quaternary mixtures of varying composition were experimentally determined. The Cubic...

  6. Multilevel Mixture Kalman Filter

    Directory of Open Access Journals (Sweden)

    Xiaodong Wang

    2004-11-01

    Full Text Available The mixture Kalman filter is a general sequential Monte Carlo technique for conditional linear dynamic systems. It generates samples of some indicator variables recursively based on sequential importance sampling (SIS and integrates out the linear and Gaussian state variables conditioned on these indicators. Due to the marginalization process, the complexity of the mixture Kalman filter is quite high if the dimension of the indicator sampling space is high. In this paper, we address this difficulty by developing a new Monte Carlo sampling scheme, namely, the multilevel mixture Kalman filter. The basic idea is to make use of the multilevel or hierarchical structure of the space from which the indicator variables take values. That is, we draw samples in a multilevel fashion, beginning with sampling from the highest-level sampling space and then draw samples from the associate subspace of the newly drawn samples in a lower-level sampling space, until reaching the desired sampling space. Such a multilevel sampling scheme can be used in conjunction with the delayed estimation method, such as the delayed-sample method, resulting in delayed multilevel mixture Kalman filter. Examples in wireless communication, specifically the coherent and noncoherent 16-QAM over flat-fading channels, are provided to demonstrate the performance of the proposed multilevel mixture Kalman filter.

  7. Effect of HNO{sub 3} and NH{sub 3} treatment on the catalytic oxidation of carbon catalyses by Cu, Mo and their mixture at the eutectic composition

    Energy Technology Data Exchange (ETDEWEB)

    Palma, M.C.; Silva, I.F.; Lobo, L.S. [Universidade Nova de Lisboa, Monte de caparica (Portugal)

    1995-12-31

    The dispersion of the active phase on the carbon surface can be improved by chemical treatment of the surface. Functional groups can affect the carbon/metal interaction leading to changes on the catalytic behaviour. The aim of this work is to study, whether chemical surface treatments influences carbon reactivity as well as molybdenum and copper dispersion in charcoal gasification by air. Several catalyst preparation techniques were used. The modified carbons were analysed by XPS and FTIR.

  8. Nitrocarburizing in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2011-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammonia-propene-hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere and...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  9. Nitrocarburising in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammoniapropene- hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere and...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  10. Mixtures Estimation and Applications

    CERN Document Server

    Mengersen, Kerrie; Titterington, Mike

    2011-01-01

    This book uses the EM (expectation maximization) algorithm to simultaneously estimate the missing data and unknown parameter(s) associated with a data set. The parameters describe the component distributions of the mixture; the distributions may be continuous or discrete. The editors provide a complete account of the applications, mathematical structure and statistical analysis of finite mixture distributions along with MCMC computational methods, together with a range of detailed discussions covering the applications of the methods and features chapters from the leading experts on the subject

  11. I-optimal mixture designs

    OpenAIRE

    Goos, Peter; JONES, Bradley; SYAFITRI, Utami

    2013-01-01

    In mixture experiments, the factors under study are proportions of the ingredients of a mixture. The special nature of the factors in a mixture experiment necessitates specific types of regression models, and specific types of experimental designs. Although mixture experiments usually are intended to predict the response(s) for all possible formulations of the mixture and to identify optimal proportions for each of the ingredients, little research has been done concerning their I-optimal desi...

  12. Mixtures and interactions

    NARCIS (Netherlands)

    Groten, J.P.

    2000-01-01

    Drinking water can be considered as a complex mixture that consists of tens, hundreds or thousands of chemicals of which the composition is qualitatively and quantitatively not fully known. From a public health point of view it is most relevant to answer the question of whether chemicals in drinking

  13. Study of delta18O calcite-dolomite mixtures

    International Nuclear Information System (INIS)

    Isotope ratio of oxygen in carbonate mixtures has been studied. For the purpose samples of calcite and dolomite with the known values delta18O are mixed in the ratios 9:1, 3:1, 1:1, 1:3, 1:9. Then from the mixtures prepared CO2 gas is separated using the McCrea method, delta18O of the gas is measured using mass-srectrometer. It has been established that to obtain delta18O calcite in the mixtures with calcite excess CO2 gas should be collected in the interval 15-30 min of the reaction duration and for the mixtures with dolomite excess - in the interval 5-15 min. To determine delta18O of dolomite the optimum time of CO2 gas collection for all the mixtures is 4-24 h

  14. Transport properties of supercritical fluids and their binary mixtures

    International Nuclear Information System (INIS)

    The molecular dynamics of the two supercritical fluids most applied in industry and some of their mixtures are characterized by their self-diffusion coefficients Di, measured by high pressure high resolution nuclear magnetic resonance with the strengthened glass cell technique. The technical details of the apparatus will be given. The fluids studied are carbon dioxide and ammonia. For CO2, mixtures with C6H6, H2, CH3COOH and CH3OH were investigated. The NH3 mixtures include C6H6, (CH3)3N, CH3CN and CH3OH

  15. Transport properties of supercritical fluids and their binary mixtures

    CERN Document Server

    Luedemann, H D

    2002-01-01

    The molecular dynamics of the two supercritical fluids most applied in industry and some of their mixtures are characterized by their self-diffusion coefficients D sub i , measured by high pressure high resolution nuclear magnetic resonance with the strengthened glass cell technique. The technical details of the apparatus will be given. The fluids studied are carbon dioxide and ammonia. For CO sub 2 , mixtures with C sub 6 H sub 6 , H sub 2 , CH sub 3 COOH and CH sub 3 OH were investigated. The NH sub 3 mixtures include C sub 6 H sub 6 , (CH sub 3) sub 3 N, CH sub 3 CN and CH sub 3 OH.

  16. Toxicological evaluation of chemical mixtures

    NARCIS (Netherlands)

    Feron, V.J.; Groten, J.P.

    2002-01-01

    This paper addresses major developments in the safety evaluation of chemical mixtures during the past 15 years, reviews today's state of the art of mixture toxicology, and discusses challenges ahead. Well-thought-out tailor-made mechanistic and empirical designs for studying the toxicity of mixtures

  17. Mechanical Tests of Tetrafluoride Skateboard Plain Chloroprene Rubber Bearings of Highway Bridge under Freeze-Thaw Cycle Condition%冻融条件下公路桥梁四氟滑板氯丁橡胶支座力学性能试验

    Institute of Scientific and Technical Information of China (English)

    张延年; 单春红; 郑怡; 熊卫士; 沈小俊; 高飞

    2013-01-01

    目的 研究公路桥梁四氟滑板氯丁橡胶支座经过冻融循环后的承载力变化情况,为各项公路桥梁的施工提供依据.方法 将四氟滑板氯丁橡胶支座放入标准冻融试验箱中进行100次的冻融循环处理,而后进行轴心受压及抗剪试验.与标准试件进行对比分析,研究承载力、极限抗压和抗剪强度、竖向刚度、水平等效刚度、弹性模量等各项性能指标的变化.结果 四氟滑板氯丁橡胶支座经过冻融循环处理,更易发生脆性破坏,且钢板外露、裂缝等破坏现象较标准试件更为严重.经处理的四氟滑板氯丁橡胶支座的承载力、极限抗压及抗剪强度、抗压及抗剪弹性模量小于标准试件.结论 经冻融循环处理,公路桥梁四氟滑板氯丁橡胶支座的各项力学性能指标均明显降低,建议提高四氟滑板氯丁橡胶支座的最低使用温度,严格控制其温度适用范围,在寒冷地区尽量采用天然橡胶支座.%In order to provide the basis for the construction of the highway bridge,we study the changes of capacity of the tetrafluoride skateboard plain chloroprene rubber bearings of highway bridge under freeze-thaw cycle condition. The tetrafluoride skateboard plain chloroprene rubber bearings were processed 100 times by freeze-thaw cycle in the standard freeze-thaw chamber,and then the axial compression and shear tests were carried. Compared with the standard test pieces, studied the changes of the performance indicators in the bearing capacity,the ultimate compressive strength and shear strength,vertical stiffness,horizontal e-quivalent stiffness, and elastic modulus. The results show that the tetrafluoride skateboard plain chloroprene rubber bearings which after the freeze-thaw cycle were more prone to brittle failure,the steel plate exposed, cracks and other damage phenomenon were more serious than the standard test pieces. The bearing capacity, ultimate compressive strength and shear

  18. Mixture Based Outlier Filtration

    Directory of Open Access Journals (Sweden)

    P. Pecherková

    2006-01-01

    Full Text Available Success/failure of adaptive control algorithms – especially those designed using the Linear Quadratic Gaussian criterion – depends on the quality of the process data used for model identification. One of the most harmful types of process data corruptions are outliers, i.e. ‘wrong data’ lying far away from the range of real data. The presence of outliers in the data negatively affects an estimation of the dynamics of the system. This effect is magnified when the outliers are grouped into blocks. In this paper, we propose an algorithm for outlier detection and removal. It is based on modelling the corrupted data by a two-component probabilistic mixture. The first component of the mixture models uncorrupted process data, while the second models outliers. When the outlier component is detected to be active, a prediction from the uncorrupted data component is computed and used as a reconstruction of the observed data. The resulting reconstruction filter is compared to standard methods on simulated and real data. The filter exhibits excellent properties, especially in the case of blocks of outliers. 

  19. Separation of gas mixtures

    International Nuclear Information System (INIS)

    Apparatus is described for the separation of a gaseous plasma mixture into components in some of which the original concentration of a specific ion has been greatly increased or decreased, comprising: a source for converting the gaseous mixture into a train of plasma packets; an open-ended vessel with a main section and at least one branch section, adapted to enclose along predetermined tracks the original plasma packets in the main section, and the separated plasma components in the branch sections; drive means for generating travelling magnetic waves along the predetermined tracks with the magnetic flux vector of the waves transverse to each of the tracks; and means for maintaining phase coherence between the plasma packets and the magnetic waves at a value needed for accelerating the components of the packets to different velocities and in such different directions that the plasma of each packet is divided into distinctly separate packets in some of which the original concentration of a specific ion has been greatly increased or decreased, and which plasma packets are collected from the branch sections of the vessels. (author)

  20. Toxicological evaluation of chemical mixtures.

    Science.gov (United States)

    Feron, V J; Groten, J P

    2002-06-01

    This paper addresses major developments in the safety evaluation of chemical mixtures during the past 15 years, reviews today's state of the art of mixture toxicology, and discusses challenges ahead. Well-thought-out tailor-made mechanistic and empirical designs for studying the toxicity of mixtures have gradually substituted trial-and-error approaches, improving the insight into the testability of joint action and interaction of constituents of mixtures. The acquired knowledge has successfully been used to evaluate the safety of combined exposures and complex mixtures such as, for example, the atmosphere at hazardous waste sites, drinking water disinfection by-products, natural flavouring complexes, and the combined intake of food additives. To consolidate the scientific foundation of mixture toxicology, studies are in progress to revisit the biological concepts and mathematics underlying formulas for low-dose extrapolation and risk assessment of chemical mixtures. Conspicuous developments include the production of new computer programs applicable to mixture research (CombiTool, BioMol, Reaction Network Modelling), the application of functional genomics and proteomics to mixture studies, the use of nano-optochemical sensors for in vivo imaging of physiological processes in cells, and the application of optical sensor micro- and nano-arrays for complex sample analysis. Clearly, the input of theoretical biologists, biomathematicians and bioengineers in mixture toxicology is essential for the development of this challenging branch of toxicology into a scientific subdiscipline of full value. PMID:11983277

  1. Challenges in Regulating Pesticide Mixtures

    OpenAIRE

    Debra Denton; Bruce Hammock; Craig Wheelock; Jason Belden; Michael Lydy

    2004-01-01

    This paper introduces the field of mixture toxicity and the challenges in regulating pesticide mixtures. Even though pesticides are unique chemical stressors designed to have biological activity that can affect a number of nontarget species, they are intentionally placed into the environment in large quantities. Currently, methods and terminology for evaluating mixture toxicity are poorly established. The most common approach used is the assumption of additive concentration, with the concentr...

  2. Thermal electron mobilities in low density gaseous mixtures

    International Nuclear Information System (INIS)

    A new method of obtaining thermal electron mobilities from experimental dependencies observed in the electron swarm is described; the method is suitable for both electron accepting and non-accepting systems. The electron mobilities for CO2, CH4 C2H6 as well as for N2, Ar, Xe, Kr and their mixtures with carbon dioxide are obtained. (Author)

  3. Transport Properties of operational gas mixtures used at LHC

    CERN Document Server

    Assran, Yasser

    2011-01-01

    This report summarizes some useful data on the transport characteristics of gas mixtures which are required for detection of charged particles in gas detectors. We try to replace Freon used for RPC detector in the CMS experiment with another gas while maintaining the good properties of the Freon gas mixture unchanged. We try to switch to freonless gas mixture because Freon is not a green gas, it is very expensive and its availability is decreasing. Noble gases like Ar, He, Ne and Xe (with some quenchers like carbon dioxide, methane, ethane and isobutene) are investigated. Transport parameters like drift velocity, diffusion, Townsend coefficient, attachment coefficient and Lorentz angle are computed using Garfield software for different gas mixtures and compared with experimental data.

  4. Sintering furnace with hydrogen carbon dioxide atmosphere

    International Nuclear Information System (INIS)

    A heated furnace for sintering structures of uranium oxide containing composition being introduced to the furnace is described. The furnace receives an atmosphere comprising a mixture of hydrogen and carbon dioxide as initially introduced to the furnace, and this mixture reacts in the furnace to give the presence of water vapor and carbon monoxide

  5. 气体膜分离混合气中二氧化碳的研究进展%Progress of separation of carbon dioxide from gas mixture by gas separation membrane

    Institute of Scientific and Technical Information of China (English)

    孙翀; 李洁; 孙丽艳; 许瑞娜; 郑祥; 雷洋; 杨烨

    2011-01-01

    As the carbon capture program, gas membrane separation technology is considered to be the most development potential method of the decarburization by the international community. The status of hollow fiber membrane contactors, membrane structures, systems technology and absorbent research is reviewed. Alkanolamines relatively to water and carbonates, which hold high carbon dioxide absorption rate, lower heat of reaction, reaction speed and ease of recycling, etc. ,are most widely used in the research and industrial process.%气体膜分离技术作为碳捕获方案被国际社会认为是最有发展潜力的脱碳方法之一.综述介绍了中空纤维膜接触器、膜结构、系统工艺和吸收剂的研究现状.相对于水和碳酸盐类,醇胺具有的二氧化碳吸收率高、反应热低、反应速度快以及容易再生等优点,在研究与工业过程中是应用最广泛的吸收剂之一.

  6. Effectiveness of Micro- and Nanomaterials in Asphalt Mixtures through Dynamic Modulus and Rutting Tests

    OpenAIRE

    Hui Yao; Zhanping You

    2016-01-01

    The objectives of this research are to use micro- and nanomaterials to modify the asphalt mixture and to evaluate the mechanical performance of asphalt mixtures. These micro- and nanomaterials, including carbon microfiber, Nanomer material, nanosilica, nonmodified nanoclay, and polymer modified nanoclay, were selected to blend with the control asphalt to improve the overall performance of the modified asphalt binders and mixtures. The microstructures of original materials and asphalt binders ...

  7. Evaporating Drops of Alkane Mixtures

    CERN Document Server

    Gu'ena, G; Poulard, C; Cazabat, Anne-Marie; Gu\\'{e}na, Geoffroy; Poulard, Christophe

    2005-01-01

    Alkane mixtures are model systems where the influence of surface tension gradients during the spreading and the evaporation of wetting drops can be easily studied. The surface tension gradients are mainly induced by concentration gradients, mass diffusion being a stabilising process. Depending on the relative concentration of the mixture, a rich pattern of behaviours is obtained.

  8. Easy and flexible mixture distributions

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Mabit, Stefan L.

    2013-01-01

    We propose a method to generate flexible mixture distributions that are useful for estimating models such as the mixed logit model using simulation. The method is easy to implement, yet it can approximate essentially any mixture distribution. We test it with good results in a simulation study and...

  9. Thermophysical Properties of Hydrocarbon Mixtures

    Science.gov (United States)

    SRD 4 NIST Thermophysical Properties of Hydrocarbon Mixtures (PC database for purchase)   Interactive computer program for predicting thermodynamic and transport properties of pure fluids and fluid mixtures containing up to 20 components. The components are selected from a database of 196 components, mostly hydrocarbons.

  10. Non-traditional Process of Hydrogen Containing Fuel Mixtures Production for Internal-combustion Engines

    OpenAIRE

    Gennady G. Kuvshinov; Maksim V. Popov; Evgeny A. Soloviev; Armen I. Arzumanyan; Georgy A. Peshkov

    2012-01-01

    The article justifies the perspectives of development of the environmentally sound technology of hydrogen containing fuel mixtures for internal-combustion engines based on the catalytic process of low-temperature decomposition of hydrocarbons into hydrogen and nanofibrous carbon.

  11. Gas adsorption and gas mixture separations using mixed-ligand MOF material

    Science.gov (United States)

    Hupp, Joseph T.; Mulfort, Karen L.; Snurr, Randall Q.; Bae, Youn-Sang

    2011-01-04

    A method of separating a mixture of carbon dioxiode and hydrocarbon gas using a mixed-ligand, metal-organic framework (MOF) material having metal ions coordinated to carboxylate ligands and pyridyl ligands.

  12. Understanding the amorphous-to-microcrystalline silicon transition in SiF{sub 4}/H{sub 2}/Ar gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Dornstetter, Jean-Christophe [TOTAL New Energies, 24 cours Michelet, 92069 Paris La Défense Cedex (France); LPICM-CNRS, Ecole Polytechnique, 91128 Palaiseau (France); Bruneau, Bastien; Bulkin, Pavel; Johnson, Erik V.; Roca i Cabarrocas, Pere [LPICM-CNRS, Ecole Polytechnique, 91128 Palaiseau (France)

    2014-06-21

    We report on the growth of microcrystalline silicon films from the dissociation of SiF{sub 4}/H{sub 2}/Ar gas mixtures. For this growth chemistry, the formation of HF molecules provides a clear signature of the amorphous to microcrystalline growth transition. Depositing films from silicon tetrafluoride requires the removal of F produced by SiF{sub 4} dissociation, and this removal is promoted by the addition of H{sub 2} which strongly reacts with F to form HF molecules. At low H{sub 2} flow rates, the films grow amorphous as all the available hydrogen is consumed to form HF. Above a critical flow rate, corresponding to the full removal of F, microcrystalline films are produced as there is an excess of atomic hydrogen in the plasma. A simple yet accurate phenomenological model is proposed to explain the SiF{sub 4}/H{sub 2} plasma chemistry in accordance with experimental data. This model provides some rules of thumb to achieve high deposition rates for microcrystalline silicon, namely, that increased RF power must be balanced by an increased H{sub 2} flow rate.

  13. Spectroscopic analysis of lithium terbium tetrafluoride

    DEFF Research Database (Denmark)

    Christensen, H.P.

    1978-01-01

    The absorption spectra of Tb3+ in LiTbF4 have been recorded in the spectral interval from 4000 to 25000 cm-1 and for temperatures between 2.3 and 150 K. This covers the transitions from the ground multiplet 7F6 to the multiplets 7F3, 7F2, 7F1, 7F0, and 5D4. The transitions were predominantly of e...

  14. Carbon fuel particles used in direct carbon conversion fuel cells

    Science.gov (United States)

    Cooper, John F.; Cherepy, Nerine

    2012-10-09

    A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

  15. Phase equilibria in asymmetric mixtures

    International Nuclear Information System (INIS)

    The simplified version of the Perturbed Hard-Chain Theory (SPHCT) is used to compute the phase equilibria and Henry's constants for mixtures in which the molecules are highly asymmetric both in shape and in the intermolecular potential. These mixtures include binary systems such as CO2/hydrocarbons and hydrocarbons/hydrocarbons, which are of particular interest for the oil industry. For this type of mixtures a single parameter (which is calculated from available experimental data of liquid-vapor equilibrium) is introduced. The approach yields results which compare well with the experimental behavior reported in the literature (Author)

  16. Phase Behavior of Mixtures of Ionic Liquids and Organic Solvents

    DEFF Research Database (Denmark)

    Abildskov, Jens; Ellegaard, Martin Dela; O’Connell, J.P.

    2010-01-01

    implemented, leading to an entirely predictive method for densities of mixed compressed ionic liquids. Quantitative agreement with experimental data is obtained over wide ranges of conditions. Previously, the method has been applied to solubilities of sparingly soluble gases in ionic liquids and in organic......A corresponding-states form of the generalized van der Waals equation, previously developed for mixtures of an ionic liquid and a supercritical solute, is here extended to mixtures including an ionic liquid and a solvent (water or organic). Group contributions to characteristic parameters are...... solvents. Here we show results for heavier and more-than-sparingly solutes such as carbon dioxide and propane in ionic liquids....

  17. Catalytic Enhancement of Carbon Black and Coal-Fueled Hybrid Direct Carbon Fuel Cells

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Ippolito, Davide; Kammer Hansen, Kent

    2015-01-01

    Hybrid direct carbon fuel cells (HDCFCs) consisting of a solid carbon (carbon black)-molten carbonate ((62–38 wt% Li-K)2CO3) mixtures in the anode chamber of an anode-supported solid oxide fuel cell type full-cell are tested for their electrochemical performance between 700 and 800°C. Performance...

  18. Optimal Parameters Multicomponent Mixtures Extruding

    Directory of Open Access Journals (Sweden)

    Ramil F. Sagitov

    2013-01-01

    Full Text Available Experimental research of multicomponent mixtures extruding from production wastes are carried out, unit for production of composites from different types of waste is presented. Having analyzed dependence of multicomponent mixtures extruding energy requirements on die length and components content at three values of angular rate of screw rotation, we received the values of energy requirements at optimal length of the die, angular speed and percent of binding additives.

  19. Performance of asphalt rubber mixtures

    OpenAIRE

    Thives, Liseane Padilha; Trichês, Glicério; Pereira, Paulo A. A.; Pais, Jorge C.

    2010-01-01

    Asphalt rubber mixtures are one of the most promising techniques to extend the service life of asphalt pavement overlays. Asphalt rubber binder is composed of crumb rubber from reclaimed tires and conventional asphalt. The asphalt rubber binder can be obtained through wet process in two different systems: terminal blending (produced at industrial plants) and continuous blending (produced in asphalt plants). This study presents a laboratory evaluation of asphalt rubber mixtures produced with d...

  20. Bayesian Kernel Mixtures for Counts

    OpenAIRE

    Canale, Antonio; David B Dunson

    2011-01-01

    Although Bayesian nonparametric mixture models for continuous data are well developed, there is a limited literature on related approaches for count data. A common strategy is to use a mixture of Poissons, which unfortunately is quite restrictive in not accounting for distributions having variance less than the mean. Other approaches include mixing multinomials, which requires finite support, and using a Dirichlet process prior with a Poisson base measure, which does not allow smooth deviatio...

  1. Improved synthesis of carbon nanotubes with junctions and of single-walled carbon nanotubes

    OpenAIRE

    Deepak, FL; Govindaraj, A.; Rao, CNR

    2006-01-01

    Pyrolysis of thiophene over nickel nanoparticles dispersed on silica is shown to yield Y-junction carbon nanotubes with smaller diameters than those obtained by the pyrolysis of organometallic-thiophene mixtures. In the presence of water vapour, the pyrolysis of organometallic-hydrocarbon mixtures yields single-walled nanotubes, as well as relatively narrow-diameter carbon nanotubes with Y-junctions. Pyrolysis-of organometallic-hydrocarbon mixtures, in the absence of water vapour, only gives ...

  2. Improved synthesis of carbon nanotubes with junctions and of single-walled carbon nanotubes

    Indian Academy of Sciences (India)

    F L Deepak; A Govindaraj; C N R Rao

    2006-01-01

    Pyrolysis of thiophene over nickel nanoparticles dispersed on silica is shown to yield Yjunction carbon nanotubes with smaller diameters than those obtained by the pyrolysis of organometallicthiophene mixtures. In the presence of water vapour, the pyrolysis of organometallic-hydrocarbon mixtures yields single-walled nanotubes, as well as relatively narrow-diameter carbon nanotubes with Y-junctions. Pyrolysis of organometallic-hydrocarbon mixtures, in the absence of water vapour, only gives nanotubes with T- and Y-junctions.

  3. Model Misspecification: Finite Mixture or Homogeneous?

    OpenAIRE

    Tarpey, Thaddeus; Yun, Dong; Petkova, Eva

    2008-01-01

    A common problem in statistical modelling is to distinguish between finite mixture distribution and a homogeneous non-mixture distribution. Finite mixture models are widely used in practice and often mixtures of normal densities are indistinguishable from homogenous non-normal densities. This paper illustrates what happens when the EM algorithm for normal mixtures is applied to a distribution that is a homogeneous non-mixture distribution. In particular, a population-based EM algorithm for fi...

  4. Analysis of asphalt mixtures on town roads

    OpenAIRE

    Glavica, Primož

    2006-01-01

    Asphalt mixtures are most commonly used composite for construction of top layers of different drive ways. By definition asphalt mixtures are composed of crushed rock, fill, bitumen and additives. Percentage of individual components wary according to the purpose asphalt mixture is to be used for. Asphalt mixtures must be capable of enduring different types of load. According to the type of load asphalt mixtures are divided into asphalt mixtures used for supporting layers and asp...

  5. Carbonation of ternary building cementing materials

    OpenAIRE

    Fernández Carrasco, Lucía; Torrens Martín, David; Martínez Ramírez, Sagrario

    2012-01-01

    The carbonation processes of ettringite and calcium aluminate hydrates phases developed by hydration of calcium aluminate cement, fly ash and calcium sulphate ternary mixtures have been studied. The hydrated samples were submitted to 4% of CO2 in a carbonation chamber, and were analysed, previous carbonation and after 14 and 90 days of carbonation time, by infrared spectroscopy and X-ray diffraction; the developed morphology was performed with the 14 days carbonated samples. The results evide...

  6. Mixtures of Product Components versus Mixtures of Dependence Trees

    Czech Academy of Sciences Publication Activity Database

    Grim, Jiří; Pudil, P.

    Cham: Springer, 2015, s. 365-382. (Studies in Computational Intelligence. 620). ISBN 978-3-319-26393-9. [IJCCI 2014 - International Joint Conference on Computational Intelligence (Rome/Italy). Rome (IT), 22.10.2014-24.10.2014] R&D Projects: GA ČR(CZ) GA14-02652S Grant ostatní: GA ČR(CZ) GAP403/12/1557 Institutional support: RVO:67985556 Keywords : Product mixtures * Mixtures of Dependence Trees * EM algorithm Subject RIV: BD - Theory of Information http://library.utia.cas.cz/separaty/2016/RO/grim-0452538.pdf

  7. Carbon black directed synthesis of ultrahigh mesoporous carbon aerogels

    OpenAIRE

    Macías, Carlos; Haro Remón, Marta; Rasines, Gloria; Parra Soto, José Bernardo; Ovín Ania, María Concepción

    2013-01-01

    [EN] A simple modification of the conventional sol–gel polymerization of resorcinol–formaldehyde mixtures allowed a facile preparation of ultrahigh mesoporous carbon gels. In the conventional synthesis the growth of the cluster polymer particles leading to the development of the porosity is controlled by the R/C ratio. In the presence of a carbon conductive additive, the polymerization of the reactants proceeded through the formation of less-branched polymer clusters resulting in carbon gels ...

  8. Mixtures of skewed Kalman filters

    KAUST Repository

    Kim, Hyoungmoon

    2014-01-01

    Normal state-space models are prevalent, but to increase the applicability of the Kalman filter, we propose mixtures of skewed, and extended skewed, Kalman filters. To do so, the closed skew-normal distribution is extended to a scale mixture class of closed skew-normal distributions. Some basic properties are derived and a class of closed skew. t distributions is obtained. Our suggested family of distributions is skewed and has heavy tails too, so it is appropriate for robust analysis. Our proposed special sequential Monte Carlo methods use a random mixture of the closed skew-normal distributions to approximate a target distribution. Hence it is possible to handle skewed and heavy tailed data simultaneously. These methods are illustrated with numerical experiments. © 2013 Elsevier Inc.

  9. Separating Underdetermined Convolutive Speech Mixtures

    DEFF Research Database (Denmark)

    Pedersen, Michael Syskind; Wang, DeLiang; Larsen, Jan;

    2006-01-01

    A limitation in many source separation tasks is that the number of source signals has to be known in advance. Further, in order to achieve good performance, the number of sources cannot exceed the number of sensors. In many real-world applications these limitations are too restrictive. We propose a...... method for underdetermined blind source separation of convolutive mixtures. The proposed framework is applicable for separation of instantaneous as well as convolutive speech mixtures. It is possible to iteratively extract each speech signal from the mixture by combining blind source separation...... techniques with binary time-frequency masking. In the proposed method, the number of source signals is not assumed to be known in advance and the number of sources is not limited to the number of microphones. Our approach needs only two microphones and the separated sounds are maintained as stereo signals....

  10. Preparation of conducting solid mixtures

    International Nuclear Information System (INIS)

    The application of conducting plastic mixtures to the fundamental problem of radiation dosimetry is briefly reviewed. A particular approach to achieving formulations with the necessary characteristics is described. A number of successful mixtures are defined for a number of different specific dosimetry situations. To obtain high quality stable materials requires intense blending and working of the materials at elevated temperatures. One machine that succeeds in this task is the Shonka plastics mixer-extruder. The Shonka mixer is described in complete detail. The procedures used in preparing representative formulations with this device are presented. A number of properties of successful conducting mixtures so prepared are summarized. The conditions required for molding such material are given. Several special welding methods for specific application with these formulations have been devised and are described

  11. Polarized mixtures with ionic tracers

    Energy Technology Data Exchange (ETDEWEB)

    Magnarelli, Lorenzo [Dipartimento di Ingegneria Meccanica e Strutturale, Universita di Trento, Via Mesiano 77, 38050 Povo, Trento (Italy)], E-mail: lorenzo.magnarelli@ing.unitn.it

    2009-08-14

    A model of a polarized mixture is developed and the effects of migration of ions are also accounted for. The rate of the polarization power in some way furnishes power to the mixture. The electrical external power is calculated and by means of a requirement of invariance of the power, the standard balance laws are deduced. The ions dissolved in the mixture and subject to the electric field are considered like tracers and their migration is discussed. We show that their migration is ruled by the Nernst-Planck equation. In the final section, we adapt the description of the model to the setting of complex bodies and the microstructural evolution equations are derived.

  12. Polarized mixtures with ionic tracers

    International Nuclear Information System (INIS)

    A model of a polarized mixture is developed and the effects of migration of ions are also accounted for. The rate of the polarization power in some way furnishes power to the mixture. The electrical external power is calculated and by means of a requirement of invariance of the power, the standard balance laws are deduced. The ions dissolved in the mixture and subject to the electric field are considered like tracers and their migration is discussed. We show that their migration is ruled by the Nernst-Planck equation. In the final section, we adapt the description of the model to the setting of complex bodies and the microstructural evolution equations are derived.

  13. Bayesian Kernel Mixtures for Counts.

    Science.gov (United States)

    Canale, Antonio; Dunson, David B

    2011-12-01

    Although Bayesian nonparametric mixture models for continuous data are well developed, there is a limited literature on related approaches for count data. A common strategy is to use a mixture of Poissons, which unfortunately is quite restrictive in not accounting for distributions having variance less than the mean. Other approaches include mixing multinomials, which requires finite support, and using a Dirichlet process prior with a Poisson base measure, which does not allow smooth deviations from the Poisson. As a broad class of alternative models, we propose to use nonparametric mixtures of rounded continuous kernels. An efficient Gibbs sampler is developed for posterior computation, and a simulation study is performed to assess performance. Focusing on the rounded Gaussian case, we generalize the modeling framework to account for multivariate count data, joint modeling with continuous and categorical variables, and other complications. The methods are illustrated through applications to a developmental toxicity study and marketing data. This article has supplementary material online. PMID:22523437

  14. Magnetism of carbon-based materials

    OpenAIRE

    Makarova, Tatiana

    2002-01-01

    We present a collection of experimental evidence on UFOs: Unidentified Ferromagnetic Organic structures. Five types of carbon magnets have been obtained experimentally: 1. Chains of interacting radicals 2. Carbonaceous substances with a mixture of sp2 and sp3 coordinated atoms 3. Amorphous carbon structures containing trivalent elements like P, N. B. 4. Nanographite and bulk graphite, nanodiamond, carbon nanofoam 5. Fullerenes.

  15. Accelerated Hazards Mixture Cure Model

    OpenAIRE

    Zhang, Jiajia; Peng, Yingwei

    2009-01-01

    We propose a new cure model for survival data with a surviving or cure fraction. The new model is a mixture cure model where the covariate effects on the proportion of cure and the distribution of the failure time of uncured patients are separately modeled. Unlike the existing mixture cure models, the new model allows covariate effects on the failure time distribution of uncured patients to be negligible at time zero and to increase as time goes by. Such a model is particularly useful in some...

  16. Isotope analysis of carbon by C2 molecule spectrum

    International Nuclear Information System (INIS)

    A study was made on inert gas mixture (He, Ne, Ar) with carbon-containing components (CO, CO2, CH4) under conditions of variation of mixture pressure in discharge tube, of carbon-containing components contents and the rate of gas flow through the discharge tube. The use of C2 molecule spectrum enabled to develope the spectroscopic techniques for determination of carbon isotope ratio. The method is universal with respect to molecular form of carbon-containing substance

  17. Evaluation system for CO2 emission of hot asphalt mixture

    Directory of Open Access Journals (Sweden)

    Bo Peng

    2015-04-01

    Full Text Available The highway construction industry plays an important role in economic and development, but is also a primary source of carbon emission. Accordingly, with the global climate change, energy conservation and reduction of carbon emissions have become critical issues in the highway construction industry. However, to date, a model for the highway construction industry has not been established. Hence, to implement a low-carbon construction model for highways, this study divided asphalt pavement construction into aggregate stacking, aggregate supply, and other stages, and compiled a list of energy consumption investigation. An appropriate calculation model of CO2 emission was then built. Based on the carbon emission calculation model, the proportion of carbon emissions in each stage was analyzed. The analytic hierarchy process was used to establish the system of asphalt pavement construction with a judgment matrix, thereby enabling calculation of the weight coefficient of each link. In addition, the stages of aggregate heating, asphalt heating, and asphalt mixture mixing were defined as key stages of asphalt pavement construction. Carbon emissions at these stages accounted for approximately 90% of the total carbon emissions. Carbon emissions at each stage and their impact on the environment were quantified and compared. The energy saving construction schemes as well as the environmental and socioeconomic benefits were then proposed. Through these schemes, significant reductions in carbon emissions and costs can be achieved. The results indicate that carbon emissions reduce by 32.30% and 35.93%, whereas costs reduce by 18.58% and 6.03%. The proposed energy-saving and emission reduction scheme can provide a theoretical basis and technical support for the development of low-carbon highway construction.

  18. Thermodynamics of mixtures containing alkoxyethanols

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan Antonio [G.E.T.E.F., Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, 47071 Valladolid (Spain)], E-mail: jagl@termo.uva.es; Mozo, Ismael; Fuente, Isaias Garcia de la; Cobos, Jose Carlos [G.E.T.E.F., Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, 47071 Valladolid (Spain); Riesco, Nicolas [Department of Earth Science and Engineering, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)

    2008-09-30

    The Flory model is applied to predict the isobaric expansion coefficients, {alpha}{sub P}, isentropic, {kappa}{sub S}, and isothermal, {kappa}{sub T}, compressibilities and speeds of sound, u, of the highly complex mixtures: hydroxyether + alkane, + dibutylether, + 1-butanol or + 2-methoxyethanol, 1-alkanol + alkane, and 1-alkanol + dibutylether. Predictions were obtained using the energetic parameter, {chi}{sub 12}, determined from values of excess enthalpies, H{sup E}, and from values of the excess isochoric internal energies, U{sub V}{sup E}, at equimolar composition. No meaningful differences exist between such predictions. Deviations between experimental and calculated values are lower than 2% for mixtures containing alkoxyethanols. Poorer results are obtained for 1-alkanol + dibutylether mixtures with deviations up to 5%. It is shown that predictions on {alpha}{sub P}, {kappa}{sub S}, {kappa}{sub T}, and u essentially depend on structural effects and not on the orientational effects present in the studied mixtures. Results are improved using {chi}{sub 12} values fitted to molar excess volumes. In this case, deviations are similar to those obtained from semiempirical models as free length theory, collision factor theory, or Nomoto or Junjie equations.

  19. Characterization of bioactive mixtures oligogalacturonidos

    International Nuclear Information System (INIS)

    Oligogalacturonides are pectic oligosaccharides composed of lineal chains of D-galacturonic acid, linked by α (1-4) glycosidic linkage. Oligogalacturonides' mixtures are obtained by enzymatic hydrolysis of pectins of diverse vegetal species. These oligosaccharides unchain a diverse biological activity in plants, which depends mainly on their polymerization degrees. The National Institute of Agricultural Science has a patent technology at national scale that lets to obtain a mixture of oligogalacturonides with different polymerization degree. In this work is presented the characterization of oligogalacturonides by spectrophotometric analysis attending to their uronic acids, reductor sugars, and neutral sugars content. Also the chromatographic profile of samples in study is obtained, using the derivatization with 2-aminobenzamide label and the separation by high pH anion exchange chromatography. It is achieved the separation of at least eight galacturonic acid oligomers with a variable degree of polymerization. On the other hand, the analysis by Fourier transform-infrared spectroscopy (FT-IR) showed that mixtures were composed by galacturonic acid salts. Results indicated that starting from two pectic acids with different characteristics, mixtures of oligogalacturonides of similar chemical composition could be obtained, but they differ in the proportion that they are presented

  20. THE MIXTURES OF 2.4-DINITROPHENYLHIDRAZONES OF INFERIOR CARBONYL COMPOUNDS AND THEIR HPLC SEPARATION WITH GRADIENT BINARY MIXTURES PHASES

    Directory of Open Access Journals (Sweden)

    Gheorghe Zgherea

    2008-06-01

    Full Text Available Mixtures of small quantities of carbonyl compounds are presents in foods, concerning sensorial qualities. The inferior carbonyl compounds (C2-C4, boiling point <100°C – mono and dicarbonyl – can be identified and measured their concentrations, after a separation by distillation on the water bath. They are transferred in a strongly acid solution of 2.4-dinitrophenylhidrazine (2.4-DNPH, generating a mixture of insoluble 2.4-dinitrophenylhidrazones (2.4-DNPH-ones. The 2.4-DNPH-ones are organic compounds with weak polarity, solids, crystallized, yellows and water insoluble, soluble in organic solvents. The mixture of 2.4dinitrophenylhidrazones may be separated by liquid chromatography, using the reverse phase mechanism [1-3]. This paper contains experimental and theoretical considerations to the means of separation through liquid chromatography of two synthetically and a natural mixtures that contain 2.4-DNPH-ones provided by inferior carbonyl compounds; to obtain conclude results, in the synthetically mixtures was introduce and 2.4-DNPH-ones provided by carbonyl compounds having three (acetone and propanal and four (isobutyl aldehyde atoms of carbon.

  1. Prospects for using carbon-carbon composites for EMI shielding

    Science.gov (United States)

    Gaier, James R.

    1990-01-01

    Since pyrolyzed carbon has a higher electrical conductivity than most polymers, carbon-carbon composites would be expected to have higher electromagnetic interference (EMI) shielding ability than polymeric resin composites. A rule of mixtures model of composite conductivity was used to calculate the effect on EMI shielding of substituting a pyrolyzed carbon matrix for a polymeric matrix. It was found that the improvements were small, no more than about 2 percent for the lowest conductivity fibers (ex-rayon) and less than 0.2 percent for the highest conductivity fibers (vapor grown carbon fibers). The structure of the rule of mixtures is such that the matrix conductivity would only be important in those cases where it is much higher than the fiber conductivity, as in metal matrix composites.

  2. Carbon deposition with LOX/RP-1 propellants

    Science.gov (United States)

    Lausten, M. F.; Rousar, D. C.; Buccella, S.

    1985-01-01

    The generation and deposition of carbon were studied using subscale hardware with LOX/RP-1 propellants. Deposition on a turbine simulator at preburner or gas generator conditions was evaluated at mixture ratios of 0.25 to 1.0 and chamber pressures of 750 to 1500 psia. Deposition on the combustion chamber wall was investigated at mixture ratios of 2.0 to 4.0 and chamber pressures of 1000 to 1500 psia. Significant carbon buildup was observed on the turbine simulator at low mixture ratios but no carbon deposition on the chamber walls was detected at the higher mixture ratios.

  3. Predicting the environmental fate properties of petroleum hydrocarbon mixtures

    International Nuclear Information System (INIS)

    The environmental fate and transport of petroleum products for risk assessment can be evaluated based on the physico-chemical properties of an indicator chemical or a surrogate compound, or the whole mixture. A study was conducted to develop a simple representation of the hydrocarbon mixture as if it contained only few constituents, each of which represents a large number of compounds. The products considered are gasoline, diesel fuel, and jet fuel (JP4). Each petroleum hydrocarbon was characterized as a mixture of six constituents: short chain alkanes, long chain alkanes, short chain cycloalkanes and alkenes, long chain cycloalkanes and alkenes, BTEX, and other aromatics. The carbon number used as a cut-off between short and long chain alkanes, alkenes, and cycloalkanes varies with the type of product. Each mixture has different average molecular weight, water solubility, vapor pressure, organic carbon partition coefficient, and air diffusivity. The properties of each constituent of gasoline were derived from the weighted average of all compounds belonging to each constituent group. For diesel fuel and JP4, the properties of each constituent were generated from the properties of the component most representative of the group. Any property that is missing or not available from common literature sources was derived from regression equations developed from the data base for gasoline. These regression equations express the property as function of the number of carbon atoms. The R2 values of the regression equations range from 0.82--0.92. Some case studies involving petroleum product contamination in which the estimated properties were applied are presented

  4. Asphalt rubber mixtures in Portugal: fatigue resistance

    OpenAIRE

    Miranda, Henrique; Batista, Fátima; Neves, José; Antunes, Maria de Lurdes; Fonseca, Paulo

    2009-01-01

    This paper presents a study concerning the fatigue behaviour of asphalt mixtures with bitumen modified with high content of crumb rubber used in Portugal. For assessing the fatigue behaviour of this type of mixtures, four asphalt mixtures with high content of crumb rubber were used: two field bituminous mixtures – an open-graded and a gap-graded – both with granite aggregates; and two laboratory manufactured bituminous mixtures – an open-graded mixture with granite aggregates and a gap-graded...

  5. Mixtures in nonstable Levy processes

    International Nuclear Information System (INIS)

    We analyse the Levy processes produced by means of two interconnected classes of nonstable, infinitely divisible distribution: the variance gamma and the Student laws. While the variance gamma family is closed under convolution, the Student one is not: this makes its time evolution more complicated. We prove that-at least for one particular type of Student processes suggested by recent empirical results, and for integral times-the distribution of the process is a mixture of other types of Student distributions, randomized by means of a new probability distribution. The mixture is such that along the time the asymptotic behaviour of the probability density functions always coincide with that of the generating Student law. We put forward the conjecture that this can be a general feature of the Student processes. We finally analyse the Ornstein-Uhlenbeck process driven by our Levy noises and show a few simulations of it

  6. Binary mixtures of chiral gases

    CERN Document Server

    Presilla, Carlo

    2015-01-01

    A possible solution of the well known paradox of chiral molecules is based on the idea of spontaneous symmetry breaking. At low pressure the molecules are delocalized between the two minima of a given molecular potential while at higher pressure they become localized in one minimum due to the intermolecular dipole-dipole interactions. Evidence for such a phase transition is provided by measurements of the inversion spectrum of ammonia and deuterated ammonia at different pressures. In particular, at pressure greater than a critical value no inversion line is observed. These data are well accounted for by a model previously developed and recently extended to mixtures. In the present paper, we discuss the variation of the critical pressure in binary mixtures as a function of the fractions of the constituents.

  7. Method to treat mixtures of air and rare gases, at least partly radioactive

    International Nuclear Information System (INIS)

    A method of treatment is described, applicable to a mixture of air with rare gases, especially xenon and krypton and at least partly radioactive, with special reference to gaseous effluent from spent fuel reprocessing. It involves the concentration of rare gases in liquid oxygen solution by cryogenic distillation of light gases, especially nitrogen, from the liquefied mixture, with recuperation of xenon and elimination of impurities such as nitrogen oxides, carbon dioxide, water vapor and hydrocarbons

  8. Uncertainty in Mixtures and Cumulative Risk Assessment

    Science.gov (United States)

    Humans and environmental species are rarely exposed to single chemicals. These chemicals typically affect multiple tissues through multiple modes of action, which may depend on the dose. Mixtures risk assessment may employ dose response information from the mixture of interest,...

  9. Shear viscosity of binary mixtures: The Gay–Berne potential

    International Nuclear Information System (INIS)

    Highlights: ► Most useful potential model to study the real systems is the Gay–Berne (GB) potential. ► We use GB model to examine thermodynamical properties of some anisotropic binary mixtures in two different phases. ► The integral equation methods are applied to solve numerically the Percus–Yevick (PY) equation. ► We obtain expansion coefficients of correlation functions needed to calculate the properties of studied mixtures. ► The results are compared with the available experimental data [e.g., HFC-125 + propane, R-125/143a, methanol + toluene, etc.] - Abstract: The Gay–Berne (GB) potential model is an interesting and useful model to study the real systems. Using the potential model, we intend to examine the thermodynamical properties of some anisotropic binary mixtures in two different phases, liquid and gas. For this purpose, we apply the integral equation method and solve numerically the Percus–Yevick (PY) integral equation. Then, we obtain the expansion coefficients of correlation functions to calculate the thermodynamical properties. Finally, we compare our results with the available experimental data [e.g., HFC-125 + propane, R-125/143a, methanol + toluene, benzene + methanol, cyclohexane + ethanol, benzene + ethanol, carbon tetrachloride + ethyl acetate, and methanol + ethanol]. The results show that the GB potential model is capable for predicting the thermodynamical properties of binary mixtures with acceptable accuracy.

  10. PARTICLE SEGREGATION IN FLUIDIZED BINARY-MIXTURES

    NARCIS (Netherlands)

    HOFFMANN, AC; JANSSEN, LPBM

    1993-01-01

    The particle segregation in fluidised beds consisting of different types of binary mixtures is shown to be governed by the same particle transport processes. The segregation behaviour of both ''different-density mixtures'' and ''equal-density mixtures'', two types of system which until now largely h

  11. Psychophysical studies of mixtures of tastants.

    NARCIS (Netherlands)

    Graaf, de C.

    1988-01-01

    The human perception of mixtures of tastante was studied with reference to three central issues, i.e., 1) the paradigma of equiratio taste substance mixtures. as an instrument to manipulate the physical composition of tastant mixtures. This paradiama also enables the construction of psychophysical f

  12. Mycoflora of mixtures used for feeding horses

    Directory of Open Access Journals (Sweden)

    Ewa Rutkowska

    2014-11-01

    Full Text Available In the article the pathogenic role of fungi isolated from mixtures used for feeding horses is discussed. These mixtures were used instead of substantial fodder. In the period of several to a dozen weeks after the mixtures were given an increased percent of spontaneous abortions ous in pregnant mares was observed.

  13. Some properties of explosive mixtures containing peroxides

    International Nuclear Information System (INIS)

    This study concerns mixtures of triacetone triperoxide (3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexoxonane, TATP) and ammonium nitrate (AN) with added water (W), as the case may be, and dry mixtures of TATP with urea nitrate (UN). Relative performances (RP) of the mixtures and their individual components, relative to TNT, were determined by means of ballistic mortar. The detonation energies, E0, and detonation velocities, D, were calculated for the mixtures studied by means of the thermodynamic code CHEETAH. Relationships have been found and are discussed between the RP and the E0 values related to unit volume of gaseous products of detonation of these mixtures. These relationships together with those between RP and oxygen balance values of the mixtures studied indicate different types of participation of AN and UN in the explosive decomposition of the respective mixtures. Dry TATP/UN mixtures exhibit lower RP than analogous mixtures TATP/AN containing up to 25% of water. Depending on the water content, the TATP/AN mixtures possess higher detonability values than the ANFO explosives. A semi-logarithmic relationship between the D values and oxygen coefficients has been derived for all the mixtures studied at the charge density of 1000 kg m-3. Among the mixtures studied, this relationship distinguishes several samples of the type of 'tertiary explosives' as well as samples that approach 'high explosives' in their performances and detonation velocities

  14. Investigations of reversible thermochromic mixtures

    Science.gov (United States)

    MacLaren, Douglas C.

    Three-component organic thermochromic systems have potential applications in reversible, rewritable thermal printing. In principle, such mixtures could maintain a coloured or non-coloured state at ambient temperature depending on their thermal treatment. These systems generally consist of a functional dye (1--3 mol%), a weakly acidic colour developer (5--25 mol%), and a high-melting organic solvent (75--90 mol%). Colour development occurs at the fusion temperature of the mixture, which triggers the interaction of the dye and developer. Slow cooling of the melt results in an equilibrium state with low colour density, whereas rapid cooling of the melt results in a metastable state with high colour density. The metastable state can be decoloured by heating to an intermediate decolourisation temperature at which the coloured state becomes unstable. Barriers to the widespread use of reversible, rewritable thermochromic materials include problems with colour contrast, colour stability, and decolourisation rates. Development is hindered by a lack of detailed knowledge of the interactions between components in these systems. In this study the developer-dye and developer-solvent interactions were examined for an archetypal dye/developer/solvent thermochromic system. Vibrational spectroscopy, NMR, and thermal analysis were used to examine compounds formed in developer/dye and developer/solvent binary mixtures. Rewritable thermochromic properties such as metastable colour density, equilibrium colour density, and decolourisation rates were examined and discussed in terms of the thermodynamics of the developer/dye and developer/solvent interactions. Observed thermochromic properties are shown to be strongly correlated to a competition between the dye and the solvent for interaction with the developer. Increasing the attractive interaction between the solvent and developer results in enhanced rewritable thermochromic properties.

  15. Superionic water-ammonia mixtures

    Science.gov (United States)

    Bethkenhagen, M.; Cebulla, D.; Redmer, R.; Hamel, S.

    2014-12-01

    The interior of the Giant Planets Uranus and Neptune contains large amounts of water, ammonia and methane (referred to as planetary ices). Many observable properties of these planets, such as luminosity, gravitational moments and magnetic fields, are thought to be determined by the physical and chemical properties of matter within this ice layer. Hence, the phase diagrams, equations of state and structural properties of these materials and their respective mixtures are of great interest.Especially the phase diagrams of water and ammonia gained much attention since Cavazzoni et al. [1] proposed superionic phases for these materials, which are characterized by highly mobile hydrogen ions in a lattice of oxygen and nitrogen ions, respectively. For water, the influence of such a phase on the properties of the Giant Planets as well as on exoplanets has been discussed widely. [2,3] Nevertheless, it is an open question how the properties of such a water layer change when another compound, e.g., ammonia is introduced. Considering a 1:1 mixture, we have performed ab initio simulations based on density functional theory using the VASP code [4] heating up structures which we had found from evolutionary random structure search calculations with XtalOpt [5]. We propose possible superionic water-ammonia structures present up to several Mbar. Moreover, we investigate the equation of state and transport properties of this mixture such as diffusion coefficients in order to compare with the pure compounds. These results are essential to construct new interior models for Neptune-like planets.[1] C. Cavazzoni et al., Science 283, 44 (1999).[2] R. Redmer et al., Icarus 211, 798 (2011).[3] L. Zeng and D. Sasselov, ApJ 784, 96 (2014).[4] G. Kresse and J. Hafner, Phys. Rev. B 47, 558 (1993).[5] D. C. Lonie and E. Zurek, Comput. Phys. Commun. 182, 372 (2011).

  16. The colloidal stabilization of carbon with carbon: carbon nanobubbles as both dispersant and glue for carbon nanotubes.

    Science.gov (United States)

    Kuzmicz, Danuta; Prescher, Simon; Polzer, Frank; Soll, Sebastian; Seitz, Christoph; Antonietti, Markus; Yuan, Jiayin

    2014-01-20

    The superior physical properties of carbon nanotubes (CNTs) have led to their broad application. Intrinsically, CNTs tend to agglomerate from hydrophobic interactions, which is highly undesirable for solution processing and device fabrication. Commonly, a stabilizer consisting of organic surfactants or polymers is used to disperse CNTs. Recently, we synthesized nitrogen-doped carbon hollow nanospheres (25-90 nm), termed carbon "nanobubbles". They bear superior dispersability in water and distinctive graphitic order. Herein, we describe the nanobubble-assisted dispersion of CNTs in aqueous solution upon sonication. This process relies on the π-π interaction between the two aromatic carbon nanostructures, which can process their carbon mixture in water into conductive filter membranes, ink, and discs. This stabilization can be extended to other aromatic carbons. In addition, the π-π interaction may create a new type of carbon p-n junction that can be used to improve charge separation. PMID:24311464

  17. An integral equation model for warm and hot dense mixtures

    CERN Document Server

    Starrett, C E; Daligault, J; Hamel, S

    2014-01-01

    In Starrett and Saumon [Phys. Rev. E 87, 013104 (2013)] a model for the calculation of electronic and ionic structures of warm and hot dense matter was described and validated. In that model the electronic structure of one "atom" in a plasma is determined using a density functional theory based average-atom (AA) model, and the ionic structure is determined by coupling the AA model to integral equations governing the fluid structure. That model was for plasmas with one nuclear species only. Here we extend it to treat plasmas with many nuclear species, i.e. mixtures, and apply it to a carbon-hydrogen mixture relevant to inertial confinement fusion experiments. Comparison of the predicted electronic and ionic structures with orbital-free and Kohn-Sham molecular dynamics simulations reveals excellent agreement wherever chemical bonding is not significant.

  18. Study on multimers and their structures in molecular association mixture

    Institute of Scientific and Technical Information of China (English)

    YAMAGUCHI; Yoshinori; OZAKI; Yukihiro

    2007-01-01

    Self-association system of(R)-1,3-butanediol in dilute carbon tetrachloride(CCl4)solution is studied as a model of molecular association mixture.Analysis methods including FSMWEFA(fixed-size moving window evolving factor analysis)combined with PCA(principal component analysis),SIMPLISMA (simple-to-use interactive self-modeling mixture analysis),and ITTFA(iterative target transformation factor analysis)are adopted to resolve infrared spectra of(R)-1,3-butanediol solution.Association number and equilibrium constant are computed.(R)-1,3-butanediol in dilute inert solution is determined as a monomer-trimer equilibrium system.Theoretical investigation of trimer structures is carried out with DFT(density functional theory),and structural factors are analyzed.

  19. Shear viscosity of binary mixtures: The Gay-Berne potential

    Science.gov (United States)

    Khordad, R.

    2012-05-01

    The Gay-Berne (GB) potential model is an interesting and useful model to study the real systems. Using the potential model, we intend to examine the thermodynamical properties of some anisotropic binary mixtures in two different phases, liquid and gas. For this purpose, we apply the integral equation method and solve numerically the Percus-Yevick (PY) integral equation. Then, we obtain the expansion coefficients of correlation functions to calculate the thermodynamical properties. Finally, we compare our results with the available experimental data [e.g., HFC-125 + propane, R-125/143a, methanol + toluene, benzene + methanol, cyclohexane + ethanol, benzene + ethanol, carbon tetrachloride + ethyl acetate, and methanol + ethanol]. The results show that the GB potential model is capable for predicting the thermodynamical properties of binary mixtures with acceptable accuracy.

  20. Distributed estimation of mixture models

    Czech Academy of Sciences Publication Activity Database

    Dedecius, Kamil; Reichl, Jan

    Cham : Springer, 2015 - (Frühwirth-Schnatter, S.; Bitto, A.; Kastner, G.; Posekany, A.), s. 27-36 ISBN 978-3-319-16237-9. - (Springer proceedings in mathematics & statistics). [Bayesian Young Statisticians Meeting (BAYSM 2014) /2./. Vienna (AT), 18.09.2014-19.09.2014] R&D Projects: GA ČR(CZ) GP14-06678P Institutional support: RVO:67985556 Keywords : mixture estimation * distributed estimation * quasi-Bayesian estimation Subject RIV: BB - Applied Statistics, Operational Research http://library.utia.cas.cz/separaty/2015/AS/dedecius-0445781.pdf

  1. Development of technology for reduction of radiotoxicity of uranium mixture

    International Nuclear Information System (INIS)

    The phase 1 of this research project was carried out as a project entitled 'Development of technology for reduction of actinide radiotoxicity' in 2007 to 2009. Its phase 2 was carried out as a project entitled 'Development of technology for reduction of radiotoxicity of uranium mixture' in 2010 to 2011. Five unit research items to accomplish it such as evaluation of dissolution and aquatic chemistry characteristics of U, TRU, RE, and etc elements evaluation of chemical and electrolytic dissolution characteristics of U and SIMFUEL oxides evaluation of removal of environmentally-detrimental elements, and high purity precipitation of uranium evaluation of salt-free electrolytic decarbonation characteristics, and recovery of used carbonate salt, and development of the process to treat uranium mixture materials and the relevant unit equipments and system with engineering concept. were carried out. The obtained results were as follows. -Evaluation of chemical characteristics of several uranium oxide materials and verification of insolubility properties of TRU oxides in carbonate media -Suggestion of the optimal conditions for dissolutions of uranium and SIMFUEL oxides - Development of technology for co-precipitation of environmentally-detrimental elements - Development of an electrolytic recycle way of used carbonate salt solution - Suggestion of a new conceptual process, named COL process to treat spent nuclear fuel, uranium-bearing wastes with high and low contents

  2. Carbon Nanotube Solar Cells

    OpenAIRE

    Klinger, Colin; Patel, Yogeshwari; Postma, Henk W. Ch.

    2012-01-01

    We present proof-of-concept all-carbon solar cells. They are made of a photoactive side of predominantly semiconducting nanotubes for photoconversion and a counter electrode made of a natural mixture of carbon nanotubes or graphite, connected by a liquid electrolyte through a redox reaction. The cells do not require rare source materials such as In or Pt, nor high-grade semiconductor processing equipment, do not rely on dye for photoconversion and therefore do not bleach, and are easy to fabr...

  3. Pitch carbon microsphere composite

    Science.gov (United States)

    Price, H. L.; Nelson, J. B.

    1977-01-01

    Petroleum pitch carbon microspheres were prepared by flash heating emulsified pitch and carbonizing the resulting microspheres in an inert atmosphere. Microsphere composites were obtained from a mixture of microspheres and tetraester precursor pyrrone powder. Scanning electron micrographs of the composite showed that it was an aggregate of microspheres bonded together by the pyrrone at the sphere contact points, with voids in and among the microspheres. Physical, thermal, and sorption properties of the composite are described. Composite applications could include use as a honeycomb filler in elevated-temperature load-bearing sandwich boards or in patient-treatment tables for radiation treatment of tumors.

  4. Fly ash carbon passivation

    Science.gov (United States)

    La Count, Robert B; Baltrus, John P; Kern, Douglas G

    2013-05-14

    A thermal method to passivate the carbon and/or other components in fly ash significantly decreases adsorption. The passivated carbon remains in the fly ash. Heating the fly ash to about 500 and 800 degrees C. under inert gas conditions sharply decreases the amount of surfactant adsorbed by the fly ash recovered after thermal treatment despite the fact that the carbon content remains in the fly ash. Using oxygen and inert gas mixtures, the present invention shows that a thermal treatment to about 500 degrees C. also sharply decreases the surfactant adsorption of the recovered fly ash even though most of the carbon remains intact. Also, thermal treatment to about 800 degrees C. under these same oxidative conditions shows a sharp decrease in surfactant adsorption of the recovered fly ash due to the fact that the carbon has been removed. This experiment simulates the various "carbon burnout" methods and is not a claim in this method. The present invention provides a thermal method of deactivating high carbon fly ash toward adsorption of AEAs while retaining the fly ash carbon. The fly ash can be used, for example, as a partial Portland cement replacement in air-entrained concrete, in conductive and other concretes, and for other applications.

  5. GRAVITY PIPELINE TRANSPORT FOR HARDENING FILLING MIXTURES

    Directory of Open Access Journals (Sweden)

    Leonid KROUPNIK

    2015-12-01

    Full Text Available In underground mining of solid minerals becoming increasingly common development system with stowing hardening mixtures. In this case the natural ore array after it is replaced by an artificial excavation of solidified filling mixture consisting of binder, aggregates and water. Such a mixture is prepared on the surface on special stowing complexes and transported underground at special stowing pipelines. However, it is transported to the horizons of a few kilometers, which requires a sustainable mode of motion of such a mixture in the pipeline. Hardening stowing mixture changes its rheological characteristics over time, which complicates the calculation of the parameters of pipeline transportation. The article suggests a method of determining the initial parameters of such mixtures: the status coefficient, indicator of transportability, coefficient of hydrodynamic resistance to motion of the mixture. These indicators characterize the mixture in terms of the possibility to transport it through pipes. On the basis of these indicators is proposed methodology for calculating the parameters of pipeline transport hardening filling mixtures in drift mode when traffic on the horizontal part of the mixture under pressure column of the mixture in the vertical part of the backfill of the pipeline. This technique allows stable operation is guaranteed to provide pipeline transportation.

  6. The Kinetics of Enzyme Mixtures

    Directory of Open Access Journals (Sweden)

    Simon Brown

    2014-03-01

    Full Text Available Even purified enzyme preparations are often heterogeneous. For example, preparations of aspartate aminotransferase or cytochrome oxidase can consist of several different forms of the enzyme. For this reason we consider how different the kinetics of the reactions catalysed by a mixture of forms of an enzyme must be to provide some indication of the characteristics of the species present. Based on the standard Michaelis-Menten model, we show that if the Michaelis constants (Km of two isoforms differ by a factor of at least 20 the steady-state kinetics can be used to characterise the mixture. However, even if heterogeneity is reflected in the kinetic data, the proportions of the different forms of the enzyme cannot be estimated from the kinetic data alone. Consequently, the heterogeneity of enzyme preparations is rarely reflected in measurements of their steady-state kinetics unless the species present have significantly different kinetic properties. This has two implications: (1 it is difficult, but not impossible, to detect molecular heterogeneity using kinetic data and (2 even when it is possible, a considerable quantity of high quality data is required.

  7. Carbon deposition characteristics of LO2/HC propellants

    Science.gov (United States)

    Hernandez, Rosemary; Mercer, Steve D.

    1987-01-01

    The generation and deposition of carbon have been studied using subscale hardware with LO2/RP-1, LO2/propane, and LO2/methane at low mixture ratio conditions. The deposition of carbon on the turbine simulator tubes was evaluated at mixture ratios of 0.20 to 0.60, and at chamber pressures from 720 to 1650 psia. The carbon-deposition rate is a strong function of mixture ratio and a weak function of chamber pressure. There is a mixture ratio that will minimize deposition for LO2/RP-1; a threshold mixture ratio for LO2/propane; and no deposition for LO2/methane at any mixture ratio tested. The turbine drive operating limits were defined for each fuel tested.

  8. Electron irradiation of carbon dioxide-carbon disulphide ice analog and its implication on the identification of carbon disulphide on Moon

    Indian Academy of Sciences (India)

    B Sivaraman

    2016-01-01

    Carbon dioxide (CO2) and carbon disulphide (CS2) molecular ice mixture was prepared under low temperature (85 K) astrochemical conditions. The icy mixture irradiated with keV electrons simulates the irradiation environment experienced by icy satellites and Interstellar Icy Mantles (IIM). Upon electron irradiation the chemical composition was found to have altered and the new products from irradiation were found to be carbonyl sulphide (OCS), sulphur dioxide (SO2), ozone (O3), carbon trioxide (CO3), sulphur trioxide (SO3), carbon subsulphide (C3S2) and carbon monoxide (CO). Results obtained confirm the presence of CS2 molecules in lunar south-pole probed by the Moon Impact Probe (MIP).

  9. Calculation of Binary Adsorption Equilibria: Hydrocarbons and Carbon Dioxide on Activated Carbon

    DEFF Research Database (Denmark)

    Marcussen, Lis; Krøll, A.

    1999-01-01

    Binary adsorption equilibria are calculated by means of a mathematical model for multicomponent mixtures combined with the SPD (Spreading Pressure Dependent) model for calculation of activity coefficients in the adsorbed phase. The model has been applied successfully for the adsorption of binary ...... mixtures of hydrocarbons and carbon dioxide on activated carbons. The model parameters have been determined, and the model has proven to be suited for prediction of adsorption equilibria in the investigated systems....

  10. Minimally refined biomass fuel. [carbohydrate-water-alcohol mixture

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, R.K.; Hirschfeld, T.B.

    1981-03-26

    A minimally refined fluid composition, suitable as a fuel mixture and derived from biomass material, is comprised of one or more water-soluble carbohydrates such as sucrose, one or more alcohols having less than four carbons, and water. The carbohydrate provides the fuel source; water-solubilizes the carbohydrate; and the alcohol aids in the combustion of the carbohydrate and reduces the viscosity of the carbohydrate/water solution. Because less energy is required to obtain the carbohydrate from the raw biomass than alcohol, an overall energy savings is realized compared to fuels employing alcohol as the primary fuel.

  11. Mixture distributions in human genetics research.

    Science.gov (United States)

    Schork, N J; Allison, D B; Thiel, B

    1996-06-01

    The use of mixture distributions in genetics research dates back to at least the late 1800s when Karl Pearson applied them in an analysis of crab morphometry. Pearson's use of normal mixture distributions to model the mixing of different species of crab (or 'families' of crab as he referred to them) within a defined geographic area motivated further use of mixture distributions in genetics research settings, and ultimately led to their development and recognition as intuitive modelling devices for the effects of underlying genes on quantitative phenotypic (i.e. trait) expression. In addition, mixture distributions are now used routinely to model or accommodate the genetic heterogeneity thought to underlie many human diseases. Specific applications of mixture distribution models in contemporary human genetics research are, in fact, too numerous to count. Despite this long, consistent and arguably illustrious history of use, little mention of mixture distributions in genetics research is made in many recent reviews on mixture models. This review attempts to rectify this by providing insight into the role that mixture distributions play in contemporary human genetics research. Tables providing examples from the literature that describe applications of mixture models in human genetics research are offered as a way of acquainting the interested reader with relevant studies. In addition, some of the more problematic aspects of the use of mixture models in genetics research are outlined and addressed. PMID:8817796

  12. Semiparametric mixtures of symmetric distributions

    CERN Document Server

    Butucea, Cristina

    2011-01-01

    We consider in this paper the semiparametric mixture of two distributions equal up to a shift parameter. The model is said to be semiparametric in the sense that the mixed distribution is not supposed to belong to a parametric family. In order to insure the identifiability of the model it is assumed that the mixed distribution is symmetric, the model being then defined by the mixing proportion, two location parameters, and the probability density function of the mixed distribution. We propose a new class of M-estimators of these parameters based on a Fourier approach, and prove that they are square root consistent under mild regularity conditions. Their finite-sample properties are illustrated by a Monte Carlo study and a benchmark real dataset is also studied with our method.

  13. Carbon Carbon Composites: An Overview .

    OpenAIRE

    G. Rohini Devi; K. Rama Rao

    1993-01-01

    Carbon carbon composites are a new class of engineering materials that are ceramic in nature but exhibit brittle to pseudoplastic behaviour. Carbon-carbon is a unique all-carbon composite with carbon fibre embeded in carbon matrix and is known as an inverse composite. Due to their excellent thermo-structural properties, carbon-carbon composites are used in specialised application like re-entry nose-tips, leading edges, rocket nozzles, and aircraft brake discs apart from several indust...

  14. Carbon Fiber Foam Composites and Methods for Making the Same

    Science.gov (United States)

    Leseman, Zayd Chad (Inventor); Atwater, Mark Andrew (Inventor); Phillips, Jonathan (Inventor)

    2014-01-01

    Exemplary embodiments provide methods and apparatus of forming fibrous carbon foams (FCFs). In one embodiment, FCFs can be formed by flowing a fuel rich gas mixture over a catalytic material and components to be encapsulated in a mold to form composite carbon fibers, each composite carbon fiber having a carbon phase grown to encapsulate the component in situ. The composite carbon fibers can be intertwined with one another to form FCFs having a geometry according to the mold.

  15. Evaluating permanent deformation in asphalt rubber mixtures

    OpenAIRE

    Fontes, Liseane P. T. L.; Trichês, Glicério; Pais, Jorge C.; Pereira, Paulo A. A.

    2009-01-01

    Permanent deformation or rutting, one of the most important distresses inflexible pavements, has long been a problem in asphalt mixtures. Throughout the years, researchers have used different test methods lo estimate the performance of asphalt mixtures in relation to rutting. One of the alternatives to reduce permanent deformation in asphalt pavement layers is through the use of mixtures produced with asphalt rubber This work aims at comparing the performance of a conventional dense graded mi...

  16. Microstructural characterisation of rubber modified asphalt mixtures

    OpenAIRE

    Abdul Hassan, Norhidayah

    2013-01-01

    Research to improve the performance of asphalt mixtures through the addition of crumb rubber using the dry process has continued worldwide because of its potential as a recycling option for used tires. For decades, dry mixed rubberised asphalt mixtures have performed inconsistently in field trials and laboratory evaluations. However, current research has revealed that the performance of asphalt mixtures is highly dependent on the characteristics of its internal structure or phase constituents...

  17. Performance-based asphalt mixture design methodology

    Science.gov (United States)

    Ali, Al-Hosain Mansour

    Today, several State D.O.T.s are being investigating the use of tire rubber with local conventional materials. Several of the ongoing investigations identified potential benefits from the use of these materials, including improvements in material properties and performance. One of the major problems is being associated with the transferability of asphalt rubber technology without appropriately considering the effects of the variety of conventional materials on mixture behavior and performance. Typically, the design of these mixtures is being adapted to the physical properties of the conventional materials by using the empirical Marshall mixture design and without considering fundamental mixture behavior and performance. Use of design criteria related to the most common modes of failure for asphalt mixtures, such as rutting, fatigue cracking, and low temperature thermal cracking have to be developed and used for identifying the "best mixture," in term of performance, for the specific local materials and loading conditions. The main objective of this study was the development of a mixture design methodology that considers mixture behavior and performance. In order to achieve this objective a laboratory investigation able to evaluate mixture properties that can be related to mixture performance, (in terms of rutting, low temperature cracking, moisture damage and fatigue), and simulating the actual field loading conditions that the material is being exposed to, was conducted. The results proved that the inclusion of rubber into asphalt mixtures improved physical characteristics such as elasticity, flexibility, rebound, aging properties, increased fatigue resistance, and reduced rutting potential. The possibility of coupling the traditional Marshall mix design method with parameters related to mixture behavior and performance was investigated. Also, the SHRP SUPERPAVE mix design methodology was reviewed and considered in this study for the development of an integrated

  18. Variational Theory of Mixtures in Continuum Mechanics

    OpenAIRE

    Gouin, Henri

    1990-01-01

    In continuum mechanics, the equations of motion for mixtures are derived through the use of Hamilton's extended principle which regards the mixture as a collection of distinct continua. The internal energy is assumed to be a function of densities, entropies and successive spatial gradients of each constituent. We first write the equations of motion for each constituent of an inviscid miscible mixture of fluids without chemical reactions or diffusion. Our work leads to the equations of motion ...

  19. Compositional Adjustment of Dirichlet Mixture Priors

    OpenAIRE

    Ye, Xugang; Yu, Yi-Kuo; Altschul, Stephen F.

    2010-01-01

    Dirichlet mixture priors provide a Bayesian formalism for scoring alignments of protein profiles to individual sequences, which can be generalized to constructing scores for multiple-alignment columns. A Dirichlet mixture is a probability distribution over multinomial space, each of whose components can be thought of as modeling a type of protein position. Applied to the simplest case of pairwise sequence alignment, a Dirichlet mixture is equivalent to an implied symmetric substitution matrix...

  20. A new high-throughput LC-MS method for the analysis of complex fructan mixtures

    DEFF Research Database (Denmark)

    Verspreet, Joran; Hansen, Anders Holmgaard; Dornez, Emmie;

    2014-01-01

    In this paper, a new liquid chromatography-mass spectrometry (LC-MS) method for the analysis of complex fructan mixtures is presented. In this method, columns with a trifunctional C18 alkyl stationary phase (T3) were used and their performance compared with that of a porous graphitized carbon (PGC...

  1. Non-traditional Process of Hydrogen Containing Fuel Mixtures Production for Internal-combustion Engines

    Directory of Open Access Journals (Sweden)

    Gennady G. Kuvshinov

    2012-12-01

    Full Text Available The article justifies the perspectives of development of the environmentally sound technology of hydrogen containing fuel mixtures for internal-combustion engines based on the catalytic process of low-temperature decomposition of hydrocarbons into hydrogen and nanofibrous carbon.

  2. Influence of Spur Processes on Positronium Formation in Some Mixtures of Organic Liquids

    DEFF Research Database (Denmark)

    Jansen, P.; Eldrup, Morten Mostgaard; Mogensen, O. E.;

    1974-01-01

    To test some predictions of the spur reaction model of positronium (Ps) formation, positron lifetime studies of the following binary organic mixtures: (a) dioxane/n-heptane, (b) triethylamine/n-heptane, (c) pyrrolidine/n-heptane, and (d) carbon disulphide/n-hexane were performed. The results were...

  3. Cluster kinetics model for mixtures of glassformers.

    Science.gov (United States)

    Brenskelle, Lisa A; McCoy, Benjamin J

    2007-10-14

    For glassformers we propose a binary mixture relation for parameters in a cluster kinetics model previously shown to represent pure compound data for viscosity and dielectric relaxation as functions of either temperature or pressure. The model parameters are based on activation energies and activation volumes for cluster association-dissociation processes. With the mixture parameters, we calculated dielectric relaxation times and compared the results to experimental values for binary mixtures. Mixtures of sorbitol and glycerol (seven compositions), sorbitol and xylitol (three compositions), and polychloroepihydrin and polyvinylmethylether (three compositions) were studied. PMID:17935407

  4. Shear viscosity of liquid mixtures: Mass dependence

    International Nuclear Information System (INIS)

    Expressions for zeroth, second, and fourth sum rules of transverse stress autocorrelation function of two component fluid have been derived. These sum rules and Mori's memory function formalism have been used to study shear viscosity of Ar-Kr and isotopic mixtures. It has been found that theoretical result is in good agreement with the computer simulation result for the Ar-Kr mixture. The mass dependence of shear viscosity for different mole fraction shows that deviation from ideal linear model comes even from mass difference in two species of fluid mixture. At higher mass ratio shear viscosity of mixture is not explained by any of the emperical model. (author)

  5. Investigation of interlaminar shear strength in carbon epoxy and carbon epoxy carbon nanotubes using experimental and finite element technique

    OpenAIRE

    P. Rama Lakshmi

    2012-01-01

    The present study concerns experimental and finite element analysis of carbon epoxy and carbon epoxy carbon nanotube composites to estimate interlaminar shear strength. Mechanical properties such as elastic ratios, thickness are varied for double notched specimen and the corresponding deflections and interlaminar shear strengths are estimated by ANSYS. From simple rule of mixtures, equivalent orthotropic material properties are estimated. These properties are provided as input in ANSYS to gen...

  6. IGNITION IMPROVEMENT OF LEAN NATURAL GAS MIXTURES

    Energy Technology Data Exchange (ETDEWEB)

    Jason M. Keith

    2005-02-01

    This report describes work performed during a thirty month project which involves the production of dimethyl ether (DME) on-site for use as an ignition-improving additive in a compression-ignition natural gas engine. A single cylinder spark ignition engine was converted to compression ignition operation. The engine was then fully instrumented with a cylinder pressure transducer, crank shaft position sensor, airflow meter, natural gas mass flow sensor, and an exhaust temperature sensor. Finally, the engine was interfaced with a control system for pilot injection of DME. The engine testing is currently in progress. In addition, a one-pass process to form DME from natural gas was simulated with chemical processing software. Natural gas is reformed to synthesis gas (a mixture of hydrogen and carbon monoxide), converted into methanol, and finally to DME in three steps. Of additional benefit to the internal combustion engine, the offgas from the pilot process can be mixed with the main natural gas charge and is expected to improve engine performance. Furthermore, a one-pass pilot facility was constructed to produce 3.7 liters/hour (0.98 gallons/hour) DME from methanol in order to characterize the effluent DME solution and determine suitability for engine use. Successful production of DME led to an economic estimate of completing a full natural gas-to-DME pilot process. Additional experimental work in constructing a synthesis gas to methanol reactor is in progress. The overall recommendation from this work is that natural gas to DME is not a suitable pathway to improved natural gas engine performance. The major reasons are difficulties in handling DME for pilot injection and the large capital costs associated with DME production from natural gas.

  7. Investigations in gasification of biomass mixtures using thermodynamic equilibrium and semi-equilibrium models

    Energy Technology Data Exchange (ETDEWEB)

    Buragohain, Buljit; Mahanta, Pinakeswar; Moholkar, Vijayanand S. [Center for Energy, Indian Institute of Technology Guwahati, Guwahati - 781 039, Assam (India)

    2011-07-01

    Biomass gasifiers with power generation capacities exceeding 1 MW have large biomass consumption. Availability of a single biomass in such large quantities is rather difficult, and hence, mixtures of biomasses need to be used as feed-stock for these gasifiers. This study has assessed feasibility of biomass mixtures as fuel in biomass gasifiers for decentralized power generation using thermodynamic equilibrium and semi-equilibrium (with limited carbon conversion) model employing Gibbs energy minimization. Binary mixtures of common biomasses found in northeastern states of India such as rice husk, bamboo dust and saw dust have been taken for analysis. The potential for power generation from gasifier has been evaluated on the basis of net yield (in Nm3) and LHV (in MJ/Nm3) of the producer gas obtained from gasification of 100 g of biomass mixture. The results of simulations have revealed interesting trends in performance of gasifiers with operating parameters such as air ratio, temperature of gasification and composition of the biomass mixture. For all biomass mixtures, the optimum air ratio is {approx} 0.3 with gasification temperature of 800oC. Under total equilibrium conditions, and for engine-generator efficiency of 30%, the least possible fuel consumption is found to be 0.8 kg/kW-h. As revealed in the simulations with semi-equilibrium model, this parameter shows an inverse variation with the extent of carbon conversion. For low carbon conversions ({approx} 60% or so), the specific fuel consumption could be as high as 1.5 kg/kW-h. The results of this study have also been compared with previous literature (theoretical as well as experimental) and good agreement has been found. This study, thus, has demonstrated potential of replacement of a single biomass fuel in the gasifier with mixtures of different biomasses.

  8. A Linear Gradient Theory Model for Calculating Interfacial Tensions of Mixtures

    DEFF Research Database (Denmark)

    Zou, You-Xiang; Stenby, Erling Halfdan

    1996-01-01

    In this research work, we assumed that the densities of each component in a mixture are linearly distributed across the interface between the coexisting vapor and liquid phases, and we developed a linear gradient theory model for computing interfacial tensions of mixtures, especially mixtures...... with proper scaling behavior at the critical point is at least required.Key words: linear gradient theory; interfacial tension; equation of state; influence parameter; density profile....... containing supercritical methane, argon, nitrogen, and carbon dioxide gases at high pressure. With this model it is unnecessary to solve the time-consuming density profile equations of the gradient theory model. The model has been tested on a number of mixtures at low and high pressures. The results show...

  9. Deciding which chemical mixtures risk assessment methods work best for what mixtures

    International Nuclear Information System (INIS)

    The most commonly used chemical mixtures risk assessment methods involve simple notions of additivity and toxicological similarity. Newer methods are emerging in response to the complexities of chemical mixture exposures and effects. Factors based on both science and policy drive decisions regarding whether to conduct a chemical mixtures risk assessment and, if so, which methods to employ. Scientific considerations are based on positive evidence of joint toxic action, elevated human exposure conditions or the potential for significant impacts on human health. Policy issues include legislative drivers that may mandate action even though adequate toxicity data on a specific mixture may not be available and risk assessment goals that impact the choice of risk assessment method to obtain the amount of health protection desired. This paper discusses three important concepts used to choose among available approaches for conducting a chemical mixtures risk assessment: (1) additive joint toxic action of mixture components; (2) toxicological interactions of mixture components; and (3) chemical composition of complex mixtures. It is proposed that scientific support for basic assumptions used in chemical mixtures risk assessment should be developed by expert panels, risk assessment methods experts, and laboratory toxicologists. This is imperative to further develop and refine quantitative methods and provide guidance on their appropriate applications. Risk assessors need scientific support for chemical mixtures risk assessment methods in the form of toxicological data on joint toxic action for high priority mixtures, statistical methods for analyzing dose-response for mixtures, and toxicological and statistical criteria for determining sufficient similarity of complex mixtures

  10. Thermodynamics of mixtures containing amines

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan Antonio [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain)], E-mail: jagl@termo.uva.es; Mozo, Ismael; Garcia de la Fuente, Isaias; Cobos, Jose Carlos [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain); Riesco, Nicolas [Department of Chemical Engineering, Loughborough University, Loughborough, LE113TU Leicestershire (United Kingdom)

    2008-01-30

    Mixtures with dimethyl or trimethylpyridines and alkane, aromatic compound or 1-alkanol have been examined using different theories: DISQUAC, Flory, the concentration-concentration structure factor, S{sub CC}(0), or the Kirkwood-Buff formalism. DISQUAC represents fairly well the available experimental data, and improves theoretical calculations from Dortmund UNIFAC. Two important effects have been investigated: (i) the effect of increasing the number of methyl groups attached to the aromatic ring of the amine; (ii) the effect of modifying the position of the methyl groups in this ring. The molar excess enthalpy, H{sup E}, and the molar excess volume, V{sup E}, decrease in systems with alkane or methanol as follows: pyridine > 3-methylpyridine > 3,5-dimethylpyridine and pyridine > 2-methylpyridine > 2,4-dimethylpyridine > 2,4,6-trimethylpyridine, which has been attributed to a weakening of the amine-amine interactions in the same sequences. This is in agreement with the relative variation of the effective dipole moment, {mu}-bar, and of the differences between the boiling temperature of a pyridine base and that of the homomorphic alkane. For heptane solutions, the observed H{sup E} variation, H{sup E} (3,5-dimethylpyridine) > H{sup E} (2,4-dimethylpyridine) > H{sup E} (2,6-dimethylpyridine), is explained similarly. Calculations on the basis of the Flory model confirm that orientational effects become weaker in systems with alkane in the order: pyridine > methylpyridine > dimethylpyridine > trimethylpyridine. S{sub CC}(0) calculations show that steric effects increase with the number of CH{sub 3}- groups in the pyridine base, and that the steric effects exerted by methyl groups in positions 2 and 6 are higher than when they are placed in positions 3 and 5. The hydrogen bond energy in methanol mixtures is independent of the pyridine base, and it is estimated to be -35.2 kJ mol{sup -1}. Heterocoordination in these solutions is due in part to size effects. Their

  11. Thermodynamics of mixtures containing amines

    International Nuclear Information System (INIS)

    Mixtures with dimethyl or trimethylpyridines and alkane, aromatic compound or 1-alkanol have been examined using different theories: DISQUAC, Flory, the concentration-concentration structure factor, SCC(0), or the Kirkwood-Buff formalism. DISQUAC represents fairly well the available experimental data, and improves theoretical calculations from Dortmund UNIFAC. Two important effects have been investigated: (i) the effect of increasing the number of methyl groups attached to the aromatic ring of the amine; (ii) the effect of modifying the position of the methyl groups in this ring. The molar excess enthalpy, HE, and the molar excess volume, VE, decrease in systems with alkane or methanol as follows: pyridine > 3-methylpyridine > 3,5-dimethylpyridine and pyridine > 2-methylpyridine > 2,4-dimethylpyridine > 2,4,6-trimethylpyridine, which has been attributed to a weakening of the amine-amine interactions in the same sequences. This is in agreement with the relative variation of the effective dipole moment, μ-bar, and of the differences between the boiling temperature of a pyridine base and that of the homomorphic alkane. For heptane solutions, the observed HE variation, HE (3,5-dimethylpyridine) > HE (2,4-dimethylpyridine) > HE (2,6-dimethylpyridine), is explained similarly. Calculations on the basis of the Flory model confirm that orientational effects become weaker in systems with alkane in the order: pyridine > methylpyridine > dimethylpyridine > trimethylpyridine. SCC(0) calculations show that steric effects increase with the number of CH3- groups in the pyridine base, and that the steric effects exerted by methyl groups in positions 2 and 6 are higher than when they are placed in positions 3 and 5. The hydrogen bond energy in methanol mixtures is independent of the pyridine base, and it is estimated to be -35.2 kJ mol-1. Heterocoordination in these solutions is due in part to size effects. Their structure is nearly random. The values of the local mole fractions

  12. STAR-POLYMER -- COLLOID MIXTURES

    Directory of Open Access Journals (Sweden)

    J.Dzubiella

    2002-01-01

    Full Text Available Recent results in theory and simulation of star-polymer--colloid mixtures are reviewed. We present the effective interaction between hard, colloidal particles and star polymers in a good solvent derived by monomer-resolved Molecular Dynamics simulations and theoretical arguments. The relevant parameters are the size ratio q between the stars and the colloids, as well as the number of polymeric arms f (functionality attached to the common center of the star. By covering a wide range of q's ranging from zero (star against a flat wall up to about 0.5, we establish analytical forms for the star-colloid interaction which are in excellent agreement with simulation results. By employing this cross interaction and the effective interactions between stars and colloids themselves, a demixing transition in the fluid phase is observed and systematically investigated for different arm numbers and size ratios. The demixing binodals are compared with experimental observations and found to be consistent. Furthermore, we map the full two-component system on an effective one-component description for the colloids, by inverting the two-component Ornstein-Zernike equations. Some recent results for the depletion interaction and freezing transitions are shown.

  13. Optic nerve oxygen tension in pigs and the effect of carbonic anhydrase inhibitors

    DEFF Research Database (Denmark)

    Stefánsson, E; Jensen, P K; Eysteinsson, T;

    1999-01-01

    To evaluate how the oxygen tension of the optic nerve (ONP(O)2) is affected by the administration of the carbonic anhydrase inhibitors dorzolamide and acetazolamide and by alterations in oxygen and carbon dioxide in the breathing mixture.......To evaluate how the oxygen tension of the optic nerve (ONP(O)2) is affected by the administration of the carbonic anhydrase inhibitors dorzolamide and acetazolamide and by alterations in oxygen and carbon dioxide in the breathing mixture....

  14. Carbon catalysis of reactions in the lithium SOCl2 and SO2 systems

    Science.gov (United States)

    Kilroy, W. P.

    1981-01-01

    Certain hazards associated with lithium batteries have delayed widespread acceptance of these power sources. The reactivity of ground lithium carbon mixtures was examined. The effect of carbon types on this reactivity was determined. The basic reaction involved mixtures of lithium and carbon with battery electrolyte. The various parameters that influenced this reactivity included: the nature and freshness of the carbon; the freshness, the purity, and the conductive salt of the electrolyte; and the effect of Teflon or moisture.

  15. The Modified Enskog Equation for Mixtures

    NARCIS (Netherlands)

    Beijeren, H. van; Ernst, M.H.

    1973-01-01

    In a previous paper it was shown that a modified form of the Enskog equation, applied to mixtures of hard spheres, should be considered as the correct extension of the usual Enskog equation to the case of mixtures. The main argument was that the modified Enskog equation leads to linear transport coe

  16. Rheological and commodity properties of petroleum mixtures

    International Nuclear Information System (INIS)

    Results of researches of rheological and commodity characteristics of prognosis petroleum mixtures, pumping on an Western Kazakhstan-Kumkol petroleum pipe-line are presented. It is shown, that petroleum mixtures are low viscous, low solidifying and have not viscosity anomaly at positive temperatures. (author)

  17. A gamma model for {DNA} mixture analyses

    OpenAIRE

    Cowell, R. G.; Lauritzen, S L; Mortera, J.

    2007-01-01

    We present a new methodology for analysing forensic identification problems involving DNA mixture traces where several individuals may have contributed to the trace. The model used for identification and separation of DNA mixtures is based on a gamma distribution for peak area values. In this paper we illustrate the gamma model and apply it on several real examples from forensic casework.

  18. Fibril assembly in whey protein mixtures

    NARCIS (Netherlands)

    Bolder, S.G.

    2007-01-01

    The objective of this thesis was to study fibril assembly in mixtures of whey proteins. The effect of the composition of the protein mixture on the structures and the resulting phase behaviour was investigated. The current work has shown that beta-lactoglobulin is responsible for the fibril assembly

  19. 21 CFR 82.6 - Certifiable mixtures.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Certifiable mixtures. 82.6 Section 82.6 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF CERTIFIED... mixture is harmless and suitable for use therein; and (3) No diluent (except resins, natural gum,...

  20. Separation of organic azeotropic mixtures by pervaporation

    Energy Technology Data Exchange (ETDEWEB)

    Baker, R.W.

    1991-12-01

    Distillation is a commonly used separation technique in the petroleum refining and chemical processing industries. However, there are a number of potential separations involving azetropic and close-boiling organic mixtures that cannot be separated efficiently by distillation. Pervaporation is a membrane-based process that uses selective permeation through membranes to separate liquid mixtures. Because the separation process is not affected by the relative volatility of the mixture components being separated, pervaporation can be used to separate azetropes and close-boiling mixtures. Our results showed that pervaporation membranes can be used to separate azeotropic mixtures efficiently, a result that is not achievable with simple distillation. The membranes were 5--10 times more permeable to one of the components of the mixture, concentrating it in the permeate stream. For example, the membrane was 10 times more permeable to ethanol than methyl ethyl ketone, producing 60% ethanol permeate from an azeotropic mixture of ethanol and methyl ethyl ketone containing 18% ethanol. For the ethyl acetate/water mixture, the membranes showed a very high selectivity to water (> 300) and the permeate was 50--100 times enriched in water relative to the feed. The membranes had permeate fluxes on the order of 0.1--1 kg/m{sup 2}{center dot}h in the operating range of 55--70{degrees}C. Higher fluxes were obtained by increasing the operating temperature.

  1. Separation of gas mixtures by centrifugation

    Science.gov (United States)

    Park, C.; Love, W. L.

    1972-01-01

    Magnetohydrodynamic (MHD) centrifuge utilizing electric currents and magnetic fields produces a magnetic force which develops supersonic rotational velocities in gas mixtures. Device is superior to ordinary centrifuges because rotation of gas mixture is produced by MHD force rather than mechanical means.

  2. Recursive unsupervised learning of finite mixture models

    NARCIS (Netherlands)

    Zivkovic, Zoran; Heijden, van der Ferdinand

    2004-01-01

    There are two open problems when finite mixture densities are used to model multivariate data: the selection of the number of components and the initialization. In this paper, we propose an online (recursive) algorithm that estimates the parameters of the mixture and that simultaneously selects the

  3. Mixture toxicity of PBT-like chemicals

    DEFF Research Database (Denmark)

    Syberg, Kristian; Dai, Lina; Ramskov, Tina;

    Even though most chemicals regulation is still conducted on a chemical by chemical basis, mixture toxicity is achieving increasing attention. The scientific understanding has increased substantially in the last decades, and a general consensus now seems to have been acieved that concentration...... addition is a suitable model for default estimations of mixture effects. One of the major challenges is therefore how to select specific chemicals for actual mixture toxicity assessments. Persistant chemicals are likely to be present in the environment for an extended period of time, thus increasing the...... likelihood of them being present in environmentally found mixtures. Persistant, bioaccumulative and toxic (PBT) chemicals are therefore a highly relevant group of chemicals to consider for mixture toxicity regulation. The present study evaluates to what extent a number of PBT-like chemicals posess concern...

  4. Relativistic mixtures of charged and uncharged particles

    Science.gov (United States)

    Kremer, Gilberto M.

    2014-01-01

    Mixtures of relativistic gases within the framework of Boltzmann equation are analyzed. Three systems are considered. The first one refers to a mixture of uncharged particles by using Grad's moment method, where the relativistic mixture is characterized by the moments of the distribution functions: particle four-flows, energy-momentum tensors, and third-order moment tensors. In the second Fick's law for a mixture of relativistic gases of non-disparate rest masses in a Schwarzschild metric are derived from an extension of Marle and McCormack model equations applied to a relativistic truncated Grad's distribution function, where it is shown the dependence of the diffusion coefficient on the gravitational potential. The third one consists in the derivation of the relativistic laws of Ohm and Fourier for a binary mixtures of electrons with protons and electrons with photons subjected to external electromagnetic fields and in presence of gravitational fields by using the Anderson and Witting model of the Boltzmann equation.

  5. Deformation Properties and Fatigue of Bituminous Mixtures

    Directory of Open Access Journals (Sweden)

    Frantisek Schlosser

    2013-01-01

    Full Text Available Deformation properties and fatigue performance are important characteristics of asphalt bound materials which are used for construction of pavement layers. Viscoelastic asphalt mixtures are better characterized via dynamic tests. This type of tests allows us to collate materials with regard to axle vibrations which lie usually in the range of 6 Hz–25 Hz for standard conditions. Asphalt modified for heat sensitivity in the range from −20°C to +60°C has significant impact on the overall characteristics of the mixture. Deformation properties are used as inputs for empirical mixture design, and fatigue performance of asphalt mixtures reflects the parameters of functional tests. Master curves convey properties of asphalt mixtures for various conditions and allow us to evaluate them without the need of time expensive testing.

  6. Preparation of carbon/carbon composite by pyrolysis of ethanol and methane

    International Nuclear Information System (INIS)

    Highlights: • The mixture of ethanol and methane was used as the precursor of pyrolytic carbon. • C/C composites with high textured pyrolytic carbon and high density were obtained. • At the same condition, the high textured carbon cannot be obtained using methane. • The mixture precursor is a promising candidate for C/C composites in CVI. - Abstract: A high textured carbon/carbon (C/C) composite was prepared using the mixture gas of ethanol and methane as the precursor by isothermal chemical vapor infiltration. The preform was infiltrated at 1180 °C with the gas pressure from 2 to 10 kPa. For 85 h infiltration, the average bulk density is up to 1.8 ± 0.02 g cm−3. The texture of the infiltrated carbon was studied by polarized-light microscopy and characterized with the aid of the extinction angle. Texture and fracture morphology of the pyrolytic carbon matrix were observed using scanning electronic microscope. C/C composites with high textured pyrolytic carbon matrix and high density were obtained by pyrolysis of ethanol and methane. This indicates the mixture of ethanol and methane is a promising candidate of the precursors for the preparation of C/C composites

  7. Properties of mixtures of cholesterol with phosphatidylcholine or with phosphatidylserine studied by (13)C magic angle spinning nuclear magnetic resonance.

    OpenAIRE

    Epand, Richard M.; Bain, Alex D; Sayer, Brian G; Bach, Diana; Wachtel, Ellen

    2002-01-01

    The behavior of cholesterol is different in mixtures with phosphatidylcholine as compared with phosphatidylserine. In (13)C cross polarization/magic angle spinning nuclear magnetic resonance spectra, resonance peaks of the vinylic carbons of cholesterol are a doublet in samples containing 0.3 or 0.5 mol fraction cholesterol with 1-palmitoyl-2-oleoyl phosphatidylserine (POPS) or in cholesterol monohydrate crystals, but a singlet with mixtures of cholesterol and 1-palmitoyl-2-oleoyl phosphatidy...

  8. Protonic Ammonium Nitrate Ionic Liquids and Their Mixtures: Insights into Their Thermophysical Behavior.

    Science.gov (United States)

    Canongia Lopes, José N; Esperança, José M S S; de Ferro, André Mão; Pereiro, Ana B; Plechkova, Natalia V; Rebelo, Luis P N; Seddon, Kenneth R; Vázquez-Fernández, Isabel

    2016-03-10

    This study is centered on the thermophysical characterization of different families of alkylammonium nitrate ionic liquids and their binary mixtures, namely the determination at atmospheric pressure of densities, electric conductivities and viscosities in the 288.15 liquids with differing numbers of hydrogen bond donor groups: diethylammonium nitrate (two hydrogen bond donors), triethylammonium nitrate (one hydrogen bond donor) and tetraethylammonium nitrate (no hydrogen bond donors). Finally, the behavior of mixtures with different numbers of equivalent carbon atoms in the alkylammonium cations was analyzed. The results show a quasi-ideal behavior for all monoalkylammonium nitrate mixtures. In contrast, the other mixtures show deviations from ideality, namely when the difference in the number of carbon atoms present in the cations increases or the number of hydrogen bond donors present in the cation decreases. Overall, the results clearly show that, besides the length and distribution of alkyl chains present in a cation such as alkylammonium, there are other structural and interaction parameters that influence the thermophysical properties of both pure compounds and their mixtures. PMID:26886188

  9. Foaming of mixtures of pure hydrocarbons

    Science.gov (United States)

    Robinson, J. V.; Woods, W. W.

    1950-01-01

    Mixtures of pure liquid hydrocarbons are capable of foaming. Nine hydrocarbons were mixed in pairs, in all possible combinations, and four proportions of each combination. These mixtures were sealed in glass tubes, and the foaming was tested by shaking. Mixtures of aliphatic with other aliphatic hydrocarbons, or of alkyl benzenes with other alkyl benzenes, did not foam. Mixtures of aliphatic hydrocarbons with alkyl benzenes did foam. The proportions of the mixtures greatly affected the foaming, the maximum foaming of 12 of 20 pairs being at the composition 20 percent aliphatic hydrocarbon, 80 percent alkyl benzene. Six seconds was the maximum foam lifetime of any of these mixtures. Aeroshell 120 lubricating oil was fractionated into 52 fractions and a residue by extraction with acetone in a fractionating extractor. The index of refraction, foam lifetime, color, and viscosity of these fractions were measured. Low viscosity and high index fractions were extracted first. The viscosity of the fractions extracted rose and the index decreased as fractionation proceeded. Foam lifetimes and color were lowest in the middle fractions. Significance is attached to the observation that none of the foam lifetimes of the fractions or residue is as high as the foam lifetime of the original Aeroshell, indicating that the foaming is not due to a particular foaming constituent, but rather to the entire mixture.

  10. On the mixture model for multiphase flow

    Energy Technology Data Exchange (ETDEWEB)

    Manninen, M.; Taivassalo, V. [VTT Energy, Espoo (Finland). Nuclear Energy; Kallio, S. [Aabo Akademi, Turku (Finland)

    1996-12-31

    Numerical flow simulation utilising a full multiphase model is impractical for a suspension possessing wide distributions in the particle size or density. Various approximations are usually made to simplify the computational task. In the simplest approach, the suspension is represented by a homogeneous single-phase system and the influence of the particles is taken into account in the values of the physical properties. This study concentrates on the derivation and closing of the model equations. The validity of the mixture model is also carefully analysed. Starting from the continuity and momentum equations written for each phase in a multiphase system, the field equations for the mixture are derived. The mixture equations largely resemble those for a single-phase flow but are represented in terms of the mixture density and velocity. The volume fraction for each dispersed phase is solved from a phase continuity equation. Various approaches applied in closing the mixture model equations are reviewed. An algebraic equation is derived for the velocity of a dispersed phase relative to the continuous phase. Simplifications made in calculating the relative velocity restrict the applicability of the mixture model to cases in which the particles reach the terminal velocity in a short time period compared to the characteristic time scale of the flow of the mixture. (75 refs.)

  11. Solubility modeling of refrigerant/lubricant mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Michels, H.H.; Sienel, T.H.

    1996-12-31

    A general model for predicting the solubility properties of refrigerant/lubricant mixtures has been developed based on applicable theory for the excess Gibbs energy of non-ideal solutions. In our approach, flexible thermodynamic forms are chosen to describe the properties of both the gas and liquid phases of refrigerant/lubricant mixtures. After an extensive study of models for describing non-ideal liquid effects, the Wohl-suffix equations, which have been extensively utilized in the analysis of hydrocarbon mixtures, have been developed into a general form applicable to mixtures where one component is a POE lubricant. In the present study we have analyzed several POEs where structural and thermophysical property data were available. Data were also collected from several sources on the solubility of refrigerant/lubricant binary pairs. We have developed a computer code (NISC), based on the Wohl model, that predicts dew point or bubble point conditions over a wide range of composition and temperature. Our present analysis covers mixtures containing up to three refrigerant molecules and one lubricant. The present code can be used to analyze the properties of R-410a and R-407c in mixtures with a POE lubricant. Comparisons with other models, such as the Wilson or modified Wilson equations, indicate that the Wohl-suffix equations yield more reliable predictions for HFC/POE mixtures.

  12. METHANOL REMOVAL FROM METHANOL-WATER MIXTURE USING ACTIVATED SLUDGE, AIR STRIPPING AND ADSORPTION PROCESS: COMPARATIVE STUDY

    Directory of Open Access Journals (Sweden)

    SALAM K. AL-DAWERY

    2015-12-01

    Full Text Available An experimental research has been carried out in order to examine the removal of methanol from methanol-water mixtures using three different methods; activated sludge; activated carbon and air stripping. The results showed that the methanol was totally consumed by the bacteria as quickly as the feed entered the activated sludge vessel. Air stripping process has a limited ability for removing of methanol due to strong intermolecular forces between methanol and water; however, the results showed that the percentage of methanol removed using air pressure at 0.5 bar was higher than that of using air pressure of 0.25 bar. Removal of methanol from the mixture with a methanol content of 5% using activated carbon was not successful due to the limited capacity of the of the activated carbon. Thus, the activated sludge process can be considered as the most suitable process for the treatment of methanol-water mixtures.

  13. Model structure selection in convolutive mixtures

    DEFF Research Database (Denmark)

    Dyrholm, Mads; Makeig, S.; Hansen, Lars Kai

    2006-01-01

    The CICAAR algorithm (convolutive independent component analysis with an auto-regressive inverse model) allows separation of white (i.i.d) source signals from convolutive mixtures. We introduce a source color model as a simple extension to the CICAAR which allows for a more parsimonious represent...... representation in many practical mixtures. The new filter-CICAAR allows Bayesian model selection and can help answer questions like: ’Are we actually dealing with a convolutive mixture?’. We try to answer this question for EEG data....

  14. Adsorption on mixtures of ion exchangers

    International Nuclear Information System (INIS)

    A theoretical study has been made of adsorption on mixtures of ion exchangers. The effect of variables such as the concentration of the ion being adsorbed, the concentration of the supporting electrolyte, loading, the values of the capacities and equilibrium constants for the various exchange processes, and the fraction of each adsorber in the mixture on the observed distribution coefficient has been investigated. A computer program has been written to facilitate the calculation of distribution coefficients for the adsorption of an ion on a given mixture of ion exchangers under a specified set of conditions

  15. Hormesis in mixtures -- can it be predicted?

    Science.gov (United States)

    Belz, Regina G; Cedergreen, Nina; Sørensen, Helle

    2008-10-01

    Binary mixture studies are well established for mixtures of pollutants, pesticides, or allelochemicals and sound statistical methods are available to evaluate the results in relation to reference models. The majority of mixture studies are conducted to investigate the effect of one compound on the inhibitory action of another. However, since stimulatory responses to low concentrations of chemicals are gaining increased attention and improved statistical models are available to describe this phenomenon of hormesis, scientists are challenged by the question of what will happen in the low concentration range when all or some of the chemicals in a mixture induce hormesis? Can the mixture effects still be predicted and can the size and concentration range of hormesis be predicted? The present study focused on binary mixtures with one or both compounds inducing hormesis and evaluated six data sets of root length of Lactuca sativa L. and areal growth of Lemna minor L., where substantial and reproducible hormetic responses to allelochemicals and herbicides have been found. Results showed that the concentration giving maximal growth stimulatory effects (M) and the concentration where the hormetic effect had vanished (LDS) could be predicted by the most-used reference model of concentration addition (CA), if the growth inhibitory concentrations (EC50) followed CA. In cases of deviations from CA at EC50, the maximum concentration M and the LDS concentration followed the same deviation patterns, which were described by curved isobole models. Thus, low concentration mixture effects as well as the concentration range of hormesis can be predicted applying available statistical models, if both mixture partners induce hormesis. Using monotonic concentration-response models instead of biphasic concentration-response models for the prediction of joint effects, thus ignoring hormesis, slightly overestimated the deviation from CA at EC20 and EC50, but did not alter the general

  16. Assessing exposures to inhaled complex mixtures.

    OpenAIRE

    Leaderer, B P; Lioy, P J; Spengler, J D

    1993-01-01

    In the course of daily activities, individuals spend varying amounts of time in different spaces where they are exposed to a complex mixture of gas, vapor, and particulate contaminants. The term complex is used in this paper to refer to binary mixtures as well as truly complex mixtures of three or more constituents. The diversity of the environments where pollution may occur, the number of pollutants that may be present, and the nature of the activity in the environment combine to pose a chal...

  17. Correlation of the liquid mixture viscosities

    Directory of Open Access Journals (Sweden)

    Knežević-Stevanović Anđela B.

    2012-01-01

    Full Text Available In this paper forty two selected correlation models for liquid mixture viscosities of organic compounds were tested on 219 binary and 41 ternary sets of experimental data taken from literature. The binary sets contained 3675 experimental data points for 70 different compounds. The ternary sets contained 2879 experimental data points for 29 different compounds. The Heric I, Heric-Brewer II, and Krishnan-Laddha models demonstrated the best correlative characteristics for binary mixtures (overall absolute average deviation < 2%. The Heric I, Heric-Brewer II, Krishnan-Laddha and Heric II models demonstrated the best correlative characteristics for ternary mixtures (overall absolute average deviation < 3%.

  18. Mixture Multi-Step-Ahead Prediction

    Czech Academy of Sciences Publication Activity Database

    Nagy, Ivan; Suzdaleva, Evgenia; Mlynářová, Tereza

    Piraeus: ISAST: International Society for the Advancement of Science and Technology, 2015, s. 727-738. ISBN 978-618-5180-05-8. [The 16th conference of the Applied Stochastic Models and Data Analysis (ASMDA) International Society. Piraeus (GR), 30.06.2015-4.07.2015] R&D Projects: GA ČR GA15-03564S; GA MŠk 7H14004; GA MŠk(BE) 7H14005 Institutional support: RVO:67985556 Keywords : mixture model * mixture prediction * recursive mixture estimation * dynamic pointer * active component Subject RIV: BB - Applied Statistics, Operational Research http://library.utia.cas.cz/separaty/2015/ZS/suzdaleva-0450479.pdf

  19. Corrosion response of nuclear reactor materials to mixtures of decontamination reagents

    International Nuclear Information System (INIS)

    An experimental study of the corrosiveness of mixtures of citric acid, oxalic acid and EDTA to nuclear reactor materials was undertaken. Specimens of type 304 stainless steel (SS), type 410 SS,c carbon steel (CS) 1018 and A508, and heat treated alloy 600 were suspended in recirculating mixtures of two or more of citric acid, oxalic acid and EDTA at temperatures of 900C or 1170C for 22 h. The results suggest that removal of oxalic acid from decontamination solutions should lower the corrosivity of the solutions to nuclear reactor materials, particularly 304 SS and 410 SS

  20. Corrosion response of nuclear reactor materials to mixtures of decontamination reagents

    International Nuclear Information System (INIS)

    An experimental study of the corrosiveness of mixtures of citric acid, oxalic acid, and EDTA to nuclear reactor materials was undertaken. Specimens of type 304 stainless steel (SS), type 410 SS, carbon steel (CS) 1018 and A508, and heat-treated alloy 600 were suspended in recirculating mixtures of two or more combinations of citric acid, oxalic acid, and EDTA at temperatures of 90 C or 117 C for 22 hours. The results suggest that removal of oxalic acid from decontamination solutions should lower the corrosiveness of the solutions to nuclear reactor materials, particularly types 304 SS and 410 SS

  1. Atmospheric pressure plasma treatment of glassy carbon for adhesion improvement

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Mortensen, Henrik Junge; Stenum, Bjarne; Goutianos, Stergios; Mitra, Susanta; Ghanbari-Siahkali, Afshin; Kingshott, Peter; Sørensen, Bent F.; Bindslev, Henrik

    2007-01-01

    Glassy carbon plates were treated with an atmospheric pressure dielectric barrier discharge (DBD). He gas, gas mixtures of He and reactive gases such as O2, CO2 and NH3, Ar gas and Ar/NH3 gas mixture were used as treatment gases. The oxygen and nitrogen contents on the surface as well as defect...

  2. Transparent Films from CO2 -Based Polyunsaturated Poly(ether carbonate)s: A Novel Synthesis Strategy and Fast Curing.

    Science.gov (United States)

    Subhani, Muhammad Afzal; Köhler, Burkhard; Gürtler, Christoph; Leitner, Walter; Müller, Thomas E

    2016-04-25

    Transparent films were prepared by cross-linking polyunsaturated poly(ether carbonate)s obtained by the multicomponent polymerization of CO2 , propylene oxide, maleic anhydride, and allyl glycidyl ether. Poly(ether carbonate)s with ABXBA multiblock structures were obtained by sequential addition of mixtures of propylene oxide/maleic anhydride and propylene oxide/allyl glycidyl ether during the polymerization. The simultaneous addition of both monomer mixtures provided poly(ether carbonate)s with AXA triblock structures. Both types of polyunsaturated poly(ether carbonate)s are characterized by diverse functional groups, that is, terminal hydroxy groups, maleate moieties along the polymer backbone, and pendant allyl groups that allow for versatile polymer chemistry. The combination of double bonds substituted with electron-acceptor and electron-donor groups enables particularly facile UV- or redox-initiated free-radical curing. The resulting materials are transparent and highly interesting for coating applications. PMID:27028458

  3. Investigation of Structure and Oxidation Behavior of Pitch and Resin Resultant Carbon

    Institute of Scientific and Technical Information of China (English)

    ZHUBo-quan; LINan

    1996-01-01

    The structure and oxidation behaviors of pitch carbon,resin carbon and their mixture re-sultant carbon have been investigated.The results indicate that the pitch carbon has relative higher true specific gravity,well developed crystalline and better oxidation resistance than resin carbon,With 20%-35% resin added to pitch,the structure of the resultant carbon can be modified and oxidation resistance will be improved significantly.

  4. Variational Theory of Mixtures in Continuum Mechanics

    CERN Document Server

    Gouin, Henri

    2008-01-01

    In continuum mechanics, the equations of motion for mixtures are derived through the use of Hamilton's extended principle which regards the mixture as a collection of distinct continua. The internal energy is assumed to be a function of densities, entropies and successive spatial gradients of each constituent. We first write the equations of motion for each constituent of an inviscid miscible mixture of fluids without chemical reactions or diffusion. Our work leads to the equations of motion in an universal thermodynamic form in which interaction terms subject to constitutive laws, difficult to interpret physically, do not occur. For an internal energy function of densities, entropies and spatial gradients, an equation describing the barycentric motion of the constituents is obtained. The result is extended for dissipative mixtures and an equation of energy is obtained. A form of Clausius-Duhem's inequality which represents the second law of thermodynamics is deduced. In the particular case of compressible mi...

  5. Predicting skin permeability from complex chemical mixtures

    International Nuclear Information System (INIS)

    Occupational and environmental exposure to topical chemicals is usually in the form of complex chemical mixtures, yet risk assessment is based on experimentally derived data from individual chemical exposures from a single, usually aqueous vehicle, or from computed physiochemical properties. We present an approach using hybrid quantitative structure permeation relationships (QSPeR) models where absorption through porcine skin flow-through diffusion cells is well predicted using a QSPeR model describing the individual penetrants, coupled with a mixture factor (MF) that accounts for physicochemical properties of the vehicle/mixture components. The baseline equation is log k p = c + mMF + aΣα 2H + bΣβ 2H + sπ 2H + rR 2 + vV x where Σα 2H is the hydrogen-bond donor acidity, Σβ 2H is the hydrogen-bond acceptor basicity, π 2H is the dipolarity/polarizability, R 2 represents the excess molar refractivity, and V x is the McGowan volume of the penetrants of interest; c, m, a, b, s, r, and v are strength coefficients coupling these descriptors to skin permeability (k p) of 12 penetrants (atrazine, chlorpyrifos, ethylparathion, fenthion, methylparathion, nonylphenol, ρ-nitrophenol, pentachlorophenol, phenol, propazine, simazine, and triazine) in 24 mixtures. Mixtures consisted of full factorial combinations of vehicles (water, ethanol, propylene glycol) and additives (sodium lauryl sulfate, methyl nicotinate). An additional set of 4 penetrants (DEET, SDS, permethrin, ricinoleic acid) in different mixtures were included to assess applicability of this approach. This resulted in a dataset of 16 compounds administered in 344 treatment combinations. Across all exposures with no MF, R2 for absorption was 0.62. With the MF, correlations increased up to 0.78. Parameters correlated to the MF include refractive index, polarizability and log (1/Henry's Law Constant) of the mixture components. These factors should not be considered final as the focus of these studies was

  6. Burned gas and unburned mixture composition prediction in biodiesel-fuelled compression igniton engine

    International Nuclear Information System (INIS)

    A prediction of burned gas and unburned mixture composition from a variety of methyl ester based bio diesel combustion in compression ignition engine, in comparison with conventional diesel fuel is presented. A free-energy minimisation scheme was used to determine mixture composition. Firstly, effects of bio diesel type were studied without exhaust gas recirculation (EGR). The combustion of the higher hydrogen-to-carbon molar ratio (H/C) bio diesel resulted in lower carbon dioxide and oxygen emissions but higher water vapour in the exhaust gases, compared to those of lower H/C ratios. At the same results also show that relative air-to-fuel ratio, that bio diesel combustion gases contain a higher amount of water vapour and a higher level of carbon dioxide compared to those of diesel. Secondly, influences of EGR (burned gas fraction) addition to bio diesel-fuelled engine on unburned mixture were simulated. For both diesel and bio diesel, the increased burned gas fraction addition to the fresh charge increased carbon dioxide and water vapour emissions while lowering oxygen content, especially for the bio diesel case. The prediction was compared with experimental results from literatures; good agreement was found. This can be considered to be a means for explaining some phenomenon occurring in bio diesel-fuelled engines. (author)

  7. Mixtures of Shifted Asymmetric Laplace Distributions

    OpenAIRE

    Franczak, Brian C.; Browne, Ryan P.; McNicholas, Paul D.

    2012-01-01

    A mixture of shifted asymmetric Laplace distributions is introduced and used for clustering and classification. A variant of the EM algorithm is developed for parameter estimation by exploiting the relationship with the general inverse Gaussian distribution. This approach is mathematically elegant and relatively computationally straightforward. Our novel mixture modelling approach is demonstrated on both simulated and real data to illustrate clustering and classification applications. In thes...

  8. Bioavailability of rectally administered carbamazepine mixture.

    OpenAIRE

    Neuvonen, P J; Tokola, O.

    1987-01-01

    The relative bioavailability of carbamazepine mixture was studied after oral and rectal administration to healthy subjects. The absorption was significantly slower after the rectal than after the oral route but the total bioavailability was similar provided the mixture was not defaecated within 2 h of administration. We conclude that carbamazepine can be administered rectally, e.g. to postoperative patients in doses corresponding with oral doses.

  9. Thermodynamic scheme of inhomogeneous perfect fluid mixtures

    OpenAIRE

    Zarate, R D; Quevedo, Hernando

    2004-01-01

    We analyze the compatibility between the geometrodynamics and thermodynamics of a binary mixture of perfect fluids which describe inhomogeneous cosmological models. We generalize the thermodynamic scheme of general relativity to include the chemical potential of the fluid mixture with non-vanishing entropy production. This formalism is then applied to the case of Szekeres and Stephani families of cosmological models. The compatibility conditions turn out to impose symmetry conditions on the c...

  10. A Gaussian mixture ensemble transform filter

    OpenAIRE

    Reich, Sebastian

    2011-01-01

    We generalize the popular ensemble Kalman filter to an ensemble transform filter where the prior distribution can take the form of a Gaussian mixture or a Gaussian kernel density estimator. The design of the filter is based on a continuous formulation of the Bayesian filter analysis step. We call the new filter algorithm the ensemble Gaussian mixture filter (EGMF). The EGMF is implemented for three simple test problems (Brownian dynamics in one dimension, Langevin dynamics in two dimensions, ...

  11. Learning Mixtures of Gaussians in High Dimensions

    OpenAIRE

    Ge, Rong; Huang, Qingqing; Kakade, Sham M.

    2015-01-01

    Efficiently learning mixture of Gaussians is a fundamental problem in statistics and learning theory. Given samples coming from a random one out of k Gaussian distributions in Rn, the learning problem asks to estimate the means and the covariance matrices of these Gaussians. This learning problem arises in many areas ranging from the natural sciences to the social sciences, and has also found many machine learning applications. Unfortunately, learning mixture of Gaussians is an information th...

  12. Laboratory performance of asphalt rubber mixtures

    OpenAIRE

    Fontes, Liseane; Trichês, Glicério; Pais, Jorge; Pereira, Paulo; Minhoto, Manuel

    2009-01-01

    Asphalt rubber mixtures are one of the most promising techniques to extend the service life of asphalt pavement overlays. Asphalt rubber binder is composed of crumb rubber from reclaimed tires and conventional asphalt. The asphalt rubber binder can be obtained through wet process in two different systems: tire rubber modified asphalt binder (produced at industrial plants) and continuous blending (produced in asphalt plants). This study presents a laboratory evaluation of asphalt rubber mixtur...

  13. Porous concrete mixtures for pervious urban pavements

    OpenAIRE

    Castro, J.; Fernández, B.; Videla, C.; de Solminihac, H.

    2007-01-01

    The present study aimed to analyze the hydraulic and mechanical behaviour of a series of roller-compacted, laboratory porous concrete mixtures. The mix design variables examined were the actual void ratio in the hardened concrete and the water/cement ratio. From these results the better dosages from the mechanical and hydraulical behaviour point of view were determined. One of the designs developed was found to exhibit excellent hydraulic capacity and 20% greater strength than the mixtures re...

  14. Assessing sanitary mixtures in East African cities

    OpenAIRE

    Letema, S.C.

    2012-01-01

    The urbanisation of poverty and informality in East African cities poses a threat to environmental health, perpetuates social exclusion and inequalities, and creates service gaps (UN-Habitat, 2008). This makes conventional sanitation provision untenable citywide, giving rise to the emergence of sanitation mixtures. Sanitation mixtures have different scales, institutional arrangements, user groups, and rationalities for their establishment, location, and management. For assessing the performan...

  15. Liquid mixture viscosities correlation with rational models

    Directory of Open Access Journals (Sweden)

    Knežević-Stevanović Anđela B.

    2014-01-01

    Full Text Available In this paper twenty two selected rational correlation models for liquid mixture viscosities of organic compounds were tested on 219 binary sets of experimental data taken from literature. The binary sets contained 3675 experimental data points for 70 different compounds. The Dimitrov-Kamenski X, Dimitrov-Kamenski XII, and Dimitrov-Kamenski XIII models demonstrated the best correlative characteristics for binary mixtures with overall absolute average deviation less then 2%. [Projekat Ministarstva nauke Republike Srbije, br. 172063

  16. Isotope mixtures of hydrogen in vanadium

    International Nuclear Information System (INIS)

    The properties of isotope-mixtures of Protium and Deuterium stored in Vanadium have been studied. Protium and Deuterium are existing as interstitial-atoms on tetrahedral sites as well as on octahedral sites in this system. This feature leads to large isotopic-effects between the two isotopes. The dependence of the thermodynamic functions like heat of solution, nonconfigurational entropy, specific heat and ordering temperatures from the composition of the isotope-mixture has been determined. (orig.)

  17. Relationship inference based on DNA mixtures.

    Science.gov (United States)

    Kaur, Navreet; Bouzga, Mariam M; Dørum, Guro; Egeland, Thore

    2016-03-01

    Today, there exists a number of tools for solving kinship cases. But what happens when information comes from a mixture? DNA mixtures are in general rarely seen in kinship cases, but in a case presented to the Norwegian Institute of Public Health, sample DNA was obtained after a rape case that resulted in an unwanted pregnancy and abortion. The only available DNA from the fetus came in form of a mixture with the mother, and it was of interest to find the father of the fetus. The mother (the victim), however, refused to give her reference data and so commonly used methods for paternity testing were no longer applicable. As this case illustrates, kinship cases involving mixtures and missing reference profiles do occur and make the use of existing methods rather inconvenient. We here present statistical methods that may handle general relationship inference based on DNA mixtures. The basic idea is that likelihood calculations for mixtures can be decomposed into a series of kinship problems. This formulation of the problem facilitates the use of kinship software. We present the freely available R package relMix which extends on the R version of Familias. Complicating factors like mutations, silent alleles, and θ-correction are then easily handled for quite general family relationships, and are included in the statistical methods we develop in this paper. The methods and their implementations are exemplified on the data from the rape case. PMID:26541994

  18. Homogeneous cooling of mixtures of particle shapes

    Science.gov (United States)

    Hidalgo, R. C.; Serero, D.; Pöschel, T.

    2016-07-01

    In this work, we examine theoretically the cooling dynamics of binary mixtures of spheres and rods. To this end, we introduce a generalized mean field analytical theory, which describes the free cooling behavior of the mixture. The relevant characteristic time scale for the cooling process is derived, depending on the mixture composition and the aspect ratio of the rods. We simulate mixtures of spherocylinders and spheres using a molecular dynamics algorithm implemented on graphics processing unit (GPU) architecture. We systematically study mixtures composed of spheres and rods with several aspect ratios and varying the mixture composition. A homogeneous cooling state, where the time dependence of the system's intensive variables occurs only through a global granular temperature, is identified. We find cooling dynamics in excellent agreement with Haff's law, when using an adequate time scale. Using the scaling properties of the homogeneous cooling dynamics, we estimated numerically the efficiency of the energy interchange between rotational and translational degrees of freedom for collisions between spheres and rods.

  19. Brief report on primary mixture preparation for precise CO observation

    Science.gov (United States)

    Lee, J.; Lee, J. B.; Moon, D. M.; Kim, J. S.

    2012-04-01

    Greenhouse gases (GHG) have been known as causing materials of the greenhouse effect. Because it is very important to reduce their emission, they has been paid attention since Kyoto protocol to the United Nations Framework Convention on Climate Change. Accurate observation data of ambient GHG are vital for the study of the relationship between GHGs and global warming, but it is not easy to quantify their mixing ratios owing to their globally and temporally tiny variation. For example, mixing ratio of carbon dioxide in the atmosphere, is reported to be growing by +1.7 ppm (parts per million)/year for recen 10 years according to GAW report. CO has contributed as an indicator in that an air mass is from source or background, although it lacks its traceability. CO is known to be emitted from industry, vehicle, and biomass burning. The atmospheric lifetime of CO varies from weeks to months depending on OH radical amount however ambient CO ranges from 50 nmol/mol to 300 nmol/mol at marine boundary, from 100 nmol/mol to 500 nmol/mol at city area. In order to monitor precisely CO at ambient, the World Meteorological Organization (WMO) requires its measurement capability of 2 nmol/mol uncertainty. For these reasons, it's necessary for the measurement results to be accurate and consistent among the assigned standards. . In order to prepare CO/air standard mixtures with an absolute scale we have studied several factors on gravimetry; purity analysis of CO and an artificial air and stability including unexpected contamination during preparation and adsorption on inner wall of cylinders. Currently we are going to present the preliminary results on the development of standard mixtures with ~ 300 nmol/mol. The mixtures were verified by comparing their amount with a Gas Chromatography / Electron Capture Detector (GC/FID) and cavity ring down spectrometer (CRDS). Analytical capability during comparison is within ± 2 ppb, which satisfies WMO DQO.

  20. Thermophysical properties of supercritical fluids and fluid mixtures

    International Nuclear Information System (INIS)

    This research is concerned with the development of a quantitative scientific description of the thermodynamic and transport properties of supercritical and subcritical fluids and fluid mixtures. It is known that the thermophysical properties of fluids and fluid mixtures asymptotically close to the critical point satisfy scaling laws with universal critical exponents and universal scaling functions. However, the range of validity of these asymptotic scaling laws is quite small. As a consequence, the impact of the modern theory of critical phenomena on chemical engineering has been limited. On the other hand, an a priori estimate of the range of temperatures and densities, where critical fluctuations become significant, can be made on the basis of the so-called Ginzburg criterion. A recent analysis of this criterion suggests that this range is actually quite large and for a fluid like carbon dioxide can easily extend to 100 degrees or so above the critical temperature. Hence, the use of traditional engineering equations like cubic equations is not scientifically justified in a very wide range of temperatures and densities around the critical point. We have therefore embarked on a scientific approach to deal with the global effects of critical fluctuations on the thermophysical properties of fluids and fluid mixtures. For this purpose it is not sufficient to consider the asymptotic critical fluctuations but we need to deal also with the nonasymptotic critical fluctuations. The goal is to develop scientifically based questions that account for the crossover of the thermophysical properties from their asymptotic singular behavior in the near vicinity of the critical point to their regular behavior very far away from the critical point

  1. Dermal tumorigen PAH and complex mixtures for biological research

    International Nuclear Information System (INIS)

    Thirteen commercially available, commonly reported four-five ring dermal tumorigen PAHs, were determined in a set of complex mixtures consisting of crude and upgraded coal liquids, and petroleum crude oils and their distillate fractions. Semi-preparative scale, normal phase high performance liquid chromatographic fractionation followed by capillary column gas chromatography or gas chromatography-mass spectroscopy were used for the measurements. Deuterated or carbon-14 labeled PAH served as internal standards or allowed recovery corrections. Approaches for the preparation and measurement of radiolabeled PAH were examined to provide chemical probes for biological study. Synthetic routes for production of 14C labeled dihydrobenzo[a]pyrene and 14C- or 3H 10-azabenzo[a]pyrene are being studied to provide tracers for fundamental studies in tracheal transplant and skin penetration systems. (DT)

  2. Calculation of effective absorption coefficient for aerosols of internal mixture

    International Nuclear Information System (INIS)

    The effective absorption coefficient with time of strong absorbing aerosol made of carbon dusts and water of internal mixture is analyzed, and the influence of different wavelengths and radius ratios on it is discussed. The shorter the wavelength is, the larger the effective absorption coefficient is , and more quickly it increases during 1-100 μs, and the largest increase if 132.65% during 1-100 μs. Different ratios between inner and outer radius have large influence on the effective absorption coefficient. The larger the ratio is, the larger the effective absorption coefficient is, and more quickly it increases during 1-100 μs. The increase of the effective absorption coefficient during 1-100 μs is larger than that during 100-1000 μs, and the largest increase is 138.66% during 1-100 μs. (authors)

  3. Calculation of thermodynamic functions for hydrocarbons and their mixtures

    Science.gov (United States)

    Perkins, Jeffery; Ho, Jason; Weinberg, Noham

    2013-06-01

    Knowledge of thermodynamic parameters of oil components in their pure forms and in mixtures is vital to understanding the properties of petroleum. The fact that hydrocarbons, thermodynamically unstable at ambient conditions, are formed spontaneously at geochemical conditions from a variety of precursors, ranging from kerogen to carbon, suggests that the thermodynamic stability of hydrocarbons increases dramatically with increasing pressure and temperature. Better grasp of their thermodynamic properties at extreme conditions is therefore crucially important both for our understanding of the processes of oil formation and for our ability to design and engineer new methods of synthetic oil production. Unfortunately, with a very few exceptions of the simplest compounds, such as e.g. methane, ethane, or ethene, these properties are tabulated for rather narrow ranges of pressures and temperatures, and in most cases are listed only for standard conditions at 25°C. We propose a new computational methodology, based on classical molecular dynamics simulations, for obtaining accurate thermodynamic functions, such as Gibbs energies, entropies, and enthalpies, of oil components and their mixtures at elevated and extreme temperatures and pressures.

  4. CATALYTIC GASIFICATION OF COAL USING EUTECTIC SALT MIXTURES; FINAL

    International Nuclear Information System (INIS)

    The Gas Research Institute (GRI) estimates that by the year 2010, 40% or more of U.S. gas supply will be provided by supplements including substitute natural gas (SNG) from coal. These supplements must be cost competitive with other energy sources. The first generation technologies for coal gasification e.g. the Lurgi Pressure Gasification Process and the relatively newer technologies e.g. the KBW (Westinghouse) Ash Agglomerating Fluidized-Bed, U-Gas Ash Agglomerating Fluidized-Bed, British Gas Corporation/Lurgi Slagging Gasifier, Texaco Moving-Bed Gasifier, and Dow and Shell Gasification Processes, have several disadvantages. These disadvantages include high severities of gasification conditions, low methane production, high oxygen consumption, inability to handle caking coals, and unattractive economics. Another problem encountered in catalytic coal gasification is deactivation of hydroxide forms of alkali and alkaline earth metal catalysts by oxides of carbon (CO(sub x)). To seek solutions to these problems, a team consisting of Clark Atlanta University (CAU, a Historically Black College and University, HBCU), the University of Tennessee Space Institute (UTSI) and Georgia Institute of Technology (Georgia Tech) proposed to identify suitable low melting eutectic salt mixtures for improved coal gasification. The research objectives of this project were to: Identify appropriate eutectic salt mixture catalysts for coal gasification; Assess agglomeration tendency of catalyzed coal; Evaluate various catalyst impregnation techniques to improve initial catalyst dispersion; Determine catalyst dispersion at high carbon conversion levels; Evaluate effects of major process variables (such as temperature, system pressure, etc.) on coal gasification; Evaluate the recovery, regeneration and recycle of the spent catalysts; and Conduct an analysis and modeling of the gasification process to provide better understanding of the fundamental mechanisms and kinetics of the process

  5. Prediction of the critical reduced electric field strength for carbon dioxide and its mixtures with copper vapor from Boltzmann analysis for a gas temperature range of 300 K to 4000 K at 0.4 MPa

    International Nuclear Information System (INIS)

    The influence of copper vapor mixed in hot CO2 on dielectric breakdown properties of gas mixture at a fixed pressure of 0.4 MPa for a temperature range of 300 K–4000 K is numerically analyzed. First, the equilibrium composition of hot CO2 with different copper fractions is calculated using a method based on mass action law. The next stage is devoted to computing the electron energy distribution functions (EEDF) by solving the two-term Boltzmann equation. The reduced ionization coefficient, the reduced attachment coefficient, and the reduced effective ionization coefficient are then obtained based on the EEDF. Finally, the critical reduced electric field (E/N)cr is obtained. The results indicate that an increasing mole fraction of copper markedly reduces (E/N)cr of the CO2–Cu gas mixtures because of copper's low ionization potential and large ionization cross section. Additionally, the generation of O2 from the thermal dissociation of CO2 contributes to the increase of (E/N)cr of CO2–Cu hot gas mixtures from about 2000 K to 3500 K

  6. Non-self-sustained electric discharge in oxygen gas mixtures: singlet delta oxygen production

    International Nuclear Information System (INIS)

    The possibility of obtaining a high specific input energy in an electron-beam sustained discharge ignited in oxygen gas mixtures O2 : Ar : CO (or H2) at the total gas pressures of 10-100 Torr was experimentally demonstrated. The specific input energy per molecular component exceeded ∼6 kJ l-1 atm-1 (150 kJ mol-1) as a small amount of carbon monoxide was added into a gas mixture of oxygen and argon. It was theoretically demonstrated that one might expect to obtain a singlet delta oxygen yield of 25% exceeding its threshold value needed for an oxygen-iodine laser operation at room temperature, when maintaining a non-self-sustained discharge in oxygen gas mixtures with molecular additives CO, H2 or D2. The efficiency of singlet delta oxygen production can be as high as 40%

  7. Gasification characteristics of coke and mixture with coal in an entrained-flow gasifier

    Energy Technology Data Exchange (ETDEWEB)

    See Hoon Lee; Sang Jun Yoon; Ho Won Ra; Young Il Son; Jai Chang Hong; Jae Goo Lee [Korean Institute of Energy Research, Taejon (Republic of Korea). Gasification Research Group

    2010-08-15

    To enhance clean energy utilization and reduce greenhouse gases, various gasification technologies have been developed in the world. The gasification characteristics, such as syngas flow rate, compositions, cold gas efficiency and carbon conversion, of petroleum coke and mixture of petroleum coke and lignite were investigated in a 1 T/d entrained-flow gasifier (ID. 0.2 m x height 1.7 m) with quencher as a syngas cooler. CO concentration was 31-42 vol% and H{sub 2} concentration was almost 22 vol% in the gasification experiments of petroleum coke. In the case of mixture of petroleum coke and lignite, CO concentration was 37-47 vol% and H{sub 2} concentration was almost 25 vol% due to synergy effect. The gasification of mixture resulted in higher syngas heating value and cold gas efficiency because of the higher H{sub 2} and CO composition in syngas.

  8. Gasification characteristics of coke and mixture with coal in an entrained-flow gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Lee, See Hoon; Yoon, Sang Jun; Ra, Ho Won; Son, Young Il; Hong, Jai Chang; Lee, Jae Goo [Gasification Research Group, Korea Institute of Energy Research, 71-2 Jang-dong, Yuseong-gu, Daejeon 305-343 (Korea)

    2010-08-15

    To enhance clean energy utilization and reduce greenhouse gases, various gasification technologies have been developed in the world. The gasification characteristics, such as syngas flow rate, compositions, cold gas efficiency and carbon conversion, of petroleum coke and mixture of petroleum coke and lignite were investigated in a 1 T/d entrained-flow gasifier (I.D. 0.2 m x height 1.7 m) with quencher as a syngas cooler. CO concentration was 31-42 vol% and H{sub 2} concentration was almost 22 vol% in the gasification experiments of petroleum coke. In the case of mixture of petroleum coke and lignite, CO concentration was 37-47 vol% and H{sub 2} concentration was almost 25 vol% due to synergy effect. The gasification of mixture resulted in higher syngas heating value and cold gas efficiency because of the higher H{sub 2} and CO composition in syngas. (author)

  9. Extraction equilibrium of ytterbium(III) with sulfoxides and their mixtures

    International Nuclear Information System (INIS)

    The extraction equilibria of 175Yb from thiocyanate solutions with di-n-pentyl sulfoxide (DPSO), di-n-octyl sulfoxide (DOSO), tri-n-octylphosphine oxide (TOPO) and their mixtures in carbon tetrachloride has been investigated. A relatively small synergistic enhancement has been observed with mixtures of dialkyl sulfoxides (DPSO + DOSO) and also with mixtures of DPSO + TOPO. These extraction data have been analyzed with the aid of a computer by taking into account complexation of the metal in the aqueous phase by inorganic ligands and assuming a set of product species in the organic phase and adjusting their information constants through an interative non-linear least-squares procedure to obtain the best fit to the data. The extraction of the metal is inversely and linearly dependent upon the dielectric constant of the solvent and temperature of the system. (author) 10 refs.; 6 figs.; 3 tabs

  10. A PROCESS FOR SEPARATING AZEOTROPIC MIXTURES BY EXTRACTIVE AND CONVECTIVE DISTILLATION

    Science.gov (United States)

    Frazer, J.W.

    1961-12-19

    A method is described for separating an azeotrope of carbon tetrachloride and 1,1,2,2-tetrafluorodinitroethane boiling at 60 deg C. The ndethod comnprises, specifically, feeding azeotrope vapors admixed with a non- reactive gas into an extractive distillation column heated to a temperature preferably somewhat above the boiling point of the constant boiling mixture. A solvent, di-n-butylphthalate, is metered into the column above the gas inlet and permitted to flow downward, earrying with it the higher bomling fraction, while the constituent having the lower boiling point passes out of the top of the column with the non-reactive gas and is collected in a nitrogen cold trap. Other solvents which alter the vapor pressure relationship may be substituted. The method is generally applicable to azeotropic mixtures. A number of specific mixtures whicb may be separated are disclosed. (AEC)

  11. High density carbon materials obtained at relatively low temperature by spark plasma sintering of carbon nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Borrell, Amparo; Torrecillas, Ramon [Nanomaterials and Nanotechnology Research Center (CINN), Principado de Asturias - Consejo Superior de Investigaciones Cientificas (CSIC), Univ. de Oviedo, Parque Tecnologico de Asturias, Llanera (Spain); Fernandez, Adolfo [Fundacion ITMA, Parque Tecnologico de Asturias, Llanera (Spain); Merino, Cesar [Grupo Antolin Ingenieria, Burgos (Spain)

    2010-01-15

    Graphitic materials obtained at low temperatures are interesting for a wide range of industrial applications including bipolar plates. In this work, graphite based nanocomposites have been obtained starting from carbon nanofibers and a mixture of carbon nanofibers with 20 vol.% of alumina nanopowders. High density carbon components were obtained by using Spark Plasma Sintering at temperatures as low as 1500-1800 C for this kind of materials. The effect of spark plasma sintering parameters on the final density, and the mechanical and electrical properties of resulting nanocomposites have been investigated. Pure carbon nanofibers with around 90% of theoretical density and fracture strength of 60 MPa have been obtained at temperatures as low as 1500 C applying a pressure of 80 MPa during sintering. It has been proved that attrition milling is a suitable method for preparing homogeneous mixtures of carbon nanofibers and alumina powders. (orig.)

  12. A constitutive theory of reacting electrolyte mixtures

    Science.gov (United States)

    Costa Reis, Martina; Wang, Yongqi; Bono Maurizio Sacchi Bassi, Adalberto

    2013-11-01

    A constitutive theory of reacting electrolyte mixtures is formulated. The intermolecular interactions among the constituents of the mixture are accounted for through additional freedom degrees to each constituent of the mixture. Balance equations for polar reacting continuum mixtures are accordingly formulated and a proper set of constitutive equations is derived with basis in the Müller-Liu formulation of the second law of thermodynamics. Moreover, the non-equilibrium and equilibrium responses of the reacting mixture are investigated in detail by emphasizing the inner and reactive structures of the medium. From the balance laws and constitutive relations, the effects of molecular structure of constituents upon the fluid flow are studied. It is also demonstrated that the local thermodynamic equilibrium state can be reached without imposing that the set of independent constitutive variables is time independent, neither spatially homogeneous nor null. The resulting constitutive relations presented throughout this work are of relevance to many practical applications, such as swelling of clays, developing of bio and polymeric membranes, and use of electrorheological fluids in industrial processes. The first author acknowledges financial support from National Counsel of Technological and Scientific Development (CNPq) and German Academic Exchange Service (DAAD).

  13. Relativistic mixtures of charged and uncharged particles

    Energy Technology Data Exchange (ETDEWEB)

    Kremer, Gilberto M. [Departamento de Física, Universidade Federal do Paraná, Curitiba (Brazil)

    2014-01-14

    Mixtures of relativistic gases within the framework of Boltzmann equation are analyzed. Three systems are considered. The first one refers to a mixture of uncharged particles by using Grad’s moment method, where the relativistic mixture is characterized by the moments of the distribution functions: particle four-flows, energy-momentum tensors, and third-order moment tensors. In the second Fick’s law for a mixture of relativistic gases of non-disparate rest masses in a Schwarzschild metric are derived from an extension of Marle and McCormack model equations applied to a relativistic truncated Grad’s distribution function, where it is shown the dependence of the diffusion coefficient on the gravitational potential. The third one consists in the derivation of the relativistic laws of Ohm and Fourier for a binary mixtures of electrons with protons and electrons with photons subjected to external electromagnetic fields and in presence of gravitational fields by using the Anderson and Witting model of the Boltzmann equation.

  14. ASPECTS OF THERMODYNAMICS OF POLYMER MIXTURES

    Institute of Scientific and Technical Information of China (English)

    CHAI Zhikuan

    1987-01-01

    In this brief review article some aspects of the thermodynamics of polymer mixtures are discussed,mainly based on the author's research. The studies of poly (methyl methacrylate)/chlorinated polyethylene (CPE), poly (butyl acrylate)/CPE and CPE/CPE (different chlorine content) mixture verify the "dissimilarity" and "similarity" principles for predicting miscibility of polymer mixtures. The sign of heat of mixing of oligomeric analogues is not sufficient in predicting the miscibility. The Flory equation of state theory has been applied to simulate the phase boundaries of polymer mixtures. The empirical entropy parameter Q12 plays an important role in the calculation, this reduces the usefulness of the theory. With energy parameter X12 ≠ 0 and Q12 ≠ 0 the spinodals so calculated are reasonable compared to experiments.A hole model was suggested for the statistics of polymer mixtures. The new hole theory combines the features of both the Flory equation of state theory and the Sanchez lattice fluid theory and can be reduced to them under some conditions.

  15. Asbestos Tailings as Aggregates for Asphalt Mixture

    Institute of Scientific and Technical Information of China (English)

    LIU Xinoming; XU Linrong

    2011-01-01

    To use many asbestos tailings collected in Ya-Lu highway, and to explore the feasibility of using asbestos tailings as aggregates in common asphalt mixtures, and properties of some asphalt mixtures were evaluated as well. X-ray diffraction (XRD), X-ray fluorescent (XRF), and atomic absorption spectrophotometry (AAS) were employed to determine the solid waste content of copper, zinc, lead, and cadmium. Volume properties and pavement performances of AC-25 asphalt mixture with asbestos tailings were also evaluated compared with those with basalt as aggregates.XRD and XRF measurement results infer that asbestos tailing is an excellent road material. Volume properties of AC-25 asphalt mixture with asbestos tailings satisfied the related specifications. No heavy metals and toxic pollution were detected in AAS test and the value of pH test is 8.23, which is help to the adhesion with asphalt in the asphalt concrete. When compared with basalt, high temperature property and the resistance to low temperature cracking of AC-25 asphalt mixture was improved by using asbestos tailings as aggregates. In-service AC-25 asphalt pavement with asbestos tailings also presented excellent performance and British Pendulum Number (BPN) coefficient of surface.

  16. Cryotrapping assisted mass spectrometry for the analysis of complex gas mixtures

    International Nuclear Information System (INIS)

    A simple method is described for the unambiguous identification of the individual components in a gas mixture showing strong overlapping of their mass spectrometric cracking patterns. The method, herein referred to as cryotrapping assisted mass spectrometry, takes advantage of the different vapor pressure values of the individual components at low temperature (78 K for liquid nitrogen traps), and thus of the different depletion efficiencies and outgassing patterns during the fast cooling and slow warming up of the trap, respectively. Examples of the use of this technique for gas mixtures with application to plasma enhanced chemical vapor deposition of carbon and carbon-nitrogen hard films are shown. Detection of traces of specific C3 hydrocarbons (2 containing deposition plasmas are addressed as representative examples of specific applications of the technique

  17. Carbon nanotube composites for glucose biosensor incorporated with reverse iontophoresis function for noninvasive glucose monitoring

    OpenAIRE

    Sun, Tai-ping; Shieh, Hsiu-Li; Ching, Congo Tak-Shing; Yao, Yan-Dong; Huang, Su-Hua; Liu, Chia-Ming; Liu, Wei-Hao; Chen, Chung-Yuan

    2010-01-01

    This study aims to develop an amperometric glucose biosensor, based on carbon nanotubes material for reverse iontophoresis, fabricated by immobilizing a mixture of glucose oxidase (GOD) and multiwalled carbon nanotubes (MWCNT) epoxy-composite, on a planar screen-printed carbon electrode. MWCNT was employed to ensure proper incorporation into the epoxy mixture and faster electron transfer between the GOD and the transducer. Results showed this biosensor possesses a low detection potential (+50...

  18. Growth Temperature Effect on Carbon Nano tubes Formation by Spray Pyrolysis Method

    International Nuclear Information System (INIS)

    Carbon nano tubes has been produced by using spray pyrolysis method with no carrier gas. Carbon nano tubes were formulated from a mixture a ferrocene and benzene with certain ratio and then the mixture were injected by the sprayer into the furnace. Growth temperature was optimized in the range of 650 until 850 oC to get the high quality of carbon nano tubes. These were characterized by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX). (author)

  19. Performance Analysis of Neuro Genetic Algorithm Applied on Detecting Proportion of Components in Manhole Gas Mixture

    Directory of Open Access Journals (Sweden)

    Varun Kumar Ojha

    2012-07-01

    Full Text Available The article presents performance analysis of a real valued neuro genetic algorithm applied for the detection of proportion of the gases found in manhole gas mixture. The neural network (NN trained using genetic algorithm (GA leads to concept of neuro genetic algorithm, which is used for implementing an intelligent sensory system for the detection of component gases present in manhole gas mixture Usually a manhole gas mixture contains several toxic gases like Hydrogen Sulfide, Ammonia, Methane, Carbon Dioxide, Nitrogen Oxide, and Carbon Monoxide. A semiconductor based gas sensor array used for sensing manhole gas components is an integral part of the proposed intelligent system. It consists of many sensor elements, where each sensor element is responsible for sensing particular gas component. Multiple sensors of different gases used for detecting gas mixture of multiple gases, results in cross-sensitivity. The crosssensitivity is a major issue and the problem is viewed as pattern recognition problem. The objective of this article is to present performance analysis of the real valued neuro genetic algorithm which is applied for multiple gas detection.

  20. Performance Analysis of Neuro Genetic Algorithm Applied on Detecting Proportion of Components in Manhole Gas Mixture

    Directory of Open Access Journals (Sweden)

    Varun Kumar Ojha

    2012-08-01

    Full Text Available The article presents performance analysis of a real valued neuro genetic algorithm applied for thedetection of proportion of the gases found in manhole gas mixture. The neural network (NN trained usinggenetic algorithm (GA leads to concept of neuro genetic algorithm, which is used for implementing anintelligent sensory system for the detection of component gases present in manhole gas mixture Usually amanhole gas mixture contains several toxic gases like Hydrogen Sulfide, Ammonia, Methane, CarbonDioxide, Nitrogen Oxide, and Carbon Monoxide. A semiconductor based gas sensor array used for sensingmanhole gas components is an integral part of the proposed intelligent system. It consists of many sensorelements, where each sensor element is responsible for sensing particular gas component. Multiple sensorsof different gases used for detecting gas mixture of multiple gases, results in cross-sensitivity. The crosssensitivity is a major issue and the problem is viewed as pattern recognition problem. The objective of thisarticle is to present performance analysis of the real valued neuro genetic algorithm which is applied formultiple gas detection.

  1. Method of absorbing UF6 from gaseous mixtures in alkamine absorbents

    International Nuclear Information System (INIS)

    A method is described for recovering UF6 from gaseous mixtures by absorption in a liquid. The liquid absorbent must have a relatively low viscosity and at least one component of the absorbent is an alkamine having less than 3 carbon atoms bonded to the amino nitrogen, less than 2 of the carbon atoms other than those bonded to the amino nitrogen are free of the hydroxy radical and precipitate the absorbed uranium from the absorbent. At least one component of the absorbent is chosen from the group consisting of ethanolamine, diethanolamine, and 3-methyl-3-amino-propane-diol-1,2

  2. Helium-oxygen mixture does not improve gas exchange in mechanically ventilated children with bronchiolitis

    OpenAIRE

    Gross, Matthew F; Spear, Robert M.; Peterson, Bradley M

    2000-01-01

    Introduction: Heliox has been found to reduce both the arterial carbon dioxide tension (PaCO2) and work of breathing in children and adults with status asthmaticus. We hypothesized that, in mechanically ventilated children with bronchiolitis, increasing the ratio of helium:oxygen concentrations would improve both ventilation and oxygenation. Objective: To examine the effect of varying concentrations of heliox mixtures on ventilation and oxygenation in mechanically ventilated children with bro...

  3. Evaluating Pt-Ru/C mixtures as ethanol electro-oxidation catalysers

    OpenAIRE

    Bibian Alonso Hoyos; Javier González; Carlos Sánchez

    2010-01-01

    This work studies ethanol electro-catalytic oxidation by cyclic voltametry in sulphuric acid solutions at different temperatures and concetrations, using platinum.rutenium mixtures supported in vitreous carbon as catalysers. The results indicate that ethanol oxidation in theses electrodes is irreversible, has slow kinetics, is controlled by charge transfer and is brought about by a bi-functional reaction mechanism, this being ethanol adsorption on platinum atoms and additional oxidation of sp...

  4. In field N transfer, build-up, and leaching in ryegrass-clover mixtures

    OpenAIRE

    Rasmussen, J.; Eriksen, J.; Jensen, E.S.; Høgh-Jensen, H.

    2008-01-01

    Two field experiments investigating dynamics in grass-clover mixtures were conducted, using 15N- and 14C-labelling to trace carbon (C) and nitrogen (N) from grass (Lolium perenne L.) and clover (Trifolium repens L. and Trifolium pratense L.). The leaching of dissolved inorganic nitrogen (DIN), as measured in pore water sampled by suction cups, increased during the autumn and winter, whereas the leaching of dissolved organic nitrogen (DON) was fairly constant during this period. Leaching of 15...

  5. Characterization of transport properties of wasteform mixtures

    International Nuclear Information System (INIS)

    This study investigates the transport properties of different wasteform mixtures. The objective is to collect data to model the long-term service-life of a cement barrier/wasteform system and see how the wasteform affect the durability of the storage structure, which is expected to last many thousand years. Two different wasteform mixtures incorporating different slag and fly ash contents were tested. The materials were characterized using different experimental tests in order to estimate tortuosity, porosity, permeability and pore size distribution. The tests showed that despite a very high porosity, the wasteform mixtures exhibit very low transport properties values. Immersion tests in NaCl solution showed very slow chloride ingress in accordance with the transport properties. Furthermore, the two formulations showed a significant improvement in properties when slag content was increased. (authors)

  6. Quasi-chemical approximation for polyatomic mixtures

    CERN Document Server

    Dávila, M V; Matoz-Fernandez, D A; Ramirez-Pastor, A J

    2016-01-01

    The statistical thermodynamics of binary mixtures of polyatomic species was developed on a generalization in the spirit of the lattice-gas model and the quasi-chemical approximation (QCA). The new theoretical framework is obtained by combining: (i) the exact analytical expression for the partition function of non-interacting mixtures of linear $k$-mers and $l$-mers (species occupying $k$ sites and $l$ sites, respectively) adsorbed in one dimension, and its extension to higher dimensions; and (ii) a generalization of the classical QCA for multicomponent adsorbates and multisite-occupancy adsorption. The process is analyzed through the partial adsorption isotherms corresponding to both species of the mixture. Comparisons with analytical data from Bragg-Williams approximation (BWA) and Monte Carlo simulations are performed in order to test the validity of the theoretical model. Even though a good fitting is obtained from BWA, it is found that QCA provides a more accurate description of the phenomenon of adsorpti...

  7. MICROBIAL QUALITY OF HONEY MIXTURE WITH POLLEN

    Directory of Open Access Journals (Sweden)

    Ján Mareček

    2011-02-01

    Full Text Available Normal 0 21 MicrosoftInternetExplorer4 The aim of this study was evaluation of microbial quality in raw materials (honey, pollen and evaluation of microbial quality in honey mixture with pollen (2.91 % and 3.85 % and also dynamics of microbial groups in honey mixtures with pollen after 14 days storage at the room temperature (approximately 25 °C and in cold store (8 °C. We used dilution plating method for testing of samples. Detections of total plate microbial count (aerobic and anaerobic microorganisms, sporulating bacteria, coliform bacteria, Bifidobacterium sp., Lactobacillus sp. and microscopic fungi were performed. In general, counts of microorganisms decreased in honey mixture with pollen compared to raw pollen and these counts increased compared to natural honey. Total plate count was 5.37 log KTJ.g-1 in pollen; 1.36 log KTJ.g-1 in honey; 2.97 log KTJ.g-1 in honey mixture with 2.91 % pollen and 2.04 log KTJ.g-1 in honey mixture with 3.85 % pollen. Coliform bacteria were detected in pollen (1.77 log KTJ.g-1. Then, we found coliform bacteria in one sample of honey mixtures with pollen (2.91 % - 1.00 log KTJ.g-1.Bifidobacterium species were detected only in raw pollen. We did not findLactobacillus sp. in any of the samples. Microscopic fungi were detected on two cultivating media. Yeasts were present in pollen sample (average 5.39 log KTJ.g-1, honey mixture with 2.91 % pollen (average 2.51 log KTJ.g-1 and honey mixture with 3.85 % pollen (average 1.58 log KTJ.g-1. Filamentous microscopic fungi were detectable in pollen (average 3.38 log KTJ.g-1, in honey (only on one medium: 1.00 log KTJ.g-1, in honey mixture with 2.91 % pollen (average 1.15 log KTJ.g-1 and in honey mixture with 3.85 % pollen (1.71 %. Raw pollen contained microscopic fungi as Absidiasp., Mucor sp., Alternaria sp. andEmericella nidulans. Honey mixture with 2.91 % pollen after storage (14 days contained lower microbial counts when compared with the sample

  8. Two-Microphone Separation of Speech Mixtures

    DEFF Research Database (Denmark)

    Pedersen, Michael Syskind; Wang, DeLiang; Larsen, Jan;

    2008-01-01

    Separation of speech mixtures, often referred to as the cocktail party problem, has been studied for decades. In many source separation tasks, the separation method is limited by the assumption of at least as many sensors as sources. Further, many methods require that the number of signals within...... been combined, independent component analysis (ICA) and binary time–frequency (T–F) masking. By estimating binary masks from the outputs of an ICA algorithm, it is possible in an iterative way to extract basis speech signals from a convolutive mixture. The basis signals are afterwards improved by...... grouping similar signals. Using two microphones, we can separate, in principle, an arbitrary number of mixed speech signals. We show separation results for mixtures with as many as seven speech signals under instantaneous conditions. We also show that the proposed method is applicable to segregate speech...

  9. Probabilistic mixture-based image modelling

    Czech Academy of Sciences Publication Activity Database

    Haindl, Michal; Havlíček, Vojtěch; Grim, Jiří

    2011-01-01

    Roč. 47, č. 3 (2011), s. 482-500. ISSN 0023-5954 R&D Projects: GA MŠk 1M0572; GA ČR GA102/08/0593 Grant ostatní: CESNET(CZ) 387/2010; GA MŠk(CZ) 2C06019; GA ČR(CZ) GA103/11/0335 Institutional research plan: CEZ:AV0Z10750506 Keywords : BTF texture modelling * discrete distribution mixtures * Bernoulli mixture * Gaussian mixture * multi-spectral texture modelling Subject RIV: BD - Theory of Information Impact factor: 0.454, year: 2011 http://library.utia.cas.cz/separaty/2011/RO/haindl-0360244.pdf

  10. Carbon nanotube solar cells.

    Directory of Open Access Journals (Sweden)

    Colin Klinger

    Full Text Available We present proof-of-concept all-carbon solar cells. They are made of a photoactive side of predominantly semiconducting nanotubes for photoconversion and a counter electrode made of a natural mixture of carbon nanotubes or graphite, connected by a liquid electrolyte through a redox reaction. The cells do not require rare source materials such as In or Pt, nor high-grade semiconductor processing equipment, do not rely on dye for photoconversion and therefore do not bleach, and are easy to fabricate using a spray-paint technique. We observe that cells with a lower concentration of carbon nanotubes on the active semiconducting electrode perform better than cells with a higher concentration of nanotubes. This effect is contrary to the expectation that a larger number of nanotubes would lead to more photoconversion and therefore more power generation. We attribute this to the presence of metallic nanotubes that provide a short for photo-excited electrons, bypassing the load. We demonstrate optimization strategies that improve cell efficiency by orders of magnitude. Once it is possible to make semiconducting-only carbon nanotube films, that may provide the greatest efficiency improvement.

  11. Laser-induced breakdown emission in hydrocarbon fuel mixtures

    Science.gov (United States)

    Kobayashi, Kazunobu; Bak, Moon Soo; Tanaka, Hiroki; Carter, Campbell; Do, Hyungrok

    2016-04-01

    Time-resolved emission measurements of laser-induced breakdown plasmas have been carried out to investigate the effect that gas species might have on the kinetics, particularly in excited states, and the resulting plasma properties. For this purpose, fuel-oxygen (O2)-carbon dioxide (CO2) mixtures with either helium (He) or nitrogen (N2) balance are prepared while maintaining their atomic compositions. The fuels tested in this study are methane (CH4), ethylene (C2H4), propane (C3H8), and butane (C4H10). The breakdown is produced in the mixtures (CH4/CO2/O2/He, C2H4/O2/He, C3H8/CO2/O2/He and C4H10/CO2/O2/He or CH4/CO2/O2/N2, C2H4/O2/N2, C3H8/CO2/O2/N2 and C4H10/CO2/O2/N2) at room conditions using the second harmonic of a Q-switched Nd:YAG laser (with pulse duration of 10 ns). The temporal evolution of plasma temperature is deduced from the ratio of two oxygen lines (777 nm and 823 nm) through Boltzmann analysis, while the evolution of electron number density is estimated based on Stark broadening of the Balmer-alpha (H α ) line at 656 nm and the measured plasma temperature. From the results, the temporal evolution of emission spectra and decay rates of atomic line-intensities are found to be almost identical between the breakdown plasma in the different mixtures given balancing gases. Furthermore, the temporal evolution of plasma temperature and electron number density are also found to be independent of the species compositions. Therefore, this behavior—of the breakdown emissions and plasma properties in the different mixtures with identical atomic composition—may be because the breakdown gases reach similar thermodynamic and physiochemical states immediately after the breakdown.

  12. Development of carbon membranes for hydrogen recovery

    OpenAIRE

    Grainger, David

    2007-01-01

    The recovery of hydrogen from gas mixtures with hydrocarbons may provide a commercial niche for carbon molecular sieve membranes (CMSMs). Previous work has shown that carbon membranes achieve excellent performance, with respect to hydrogen permeability and selectivity, in the separation of hydrogen from light hydrocarbons, such as CH4, and CO2. The intent of this work was to screen CMSMs derived from cellulose-hemicellulose for H2 recovery and to generate performance data so that commercial a...

  13. Thermodynamic scheme of inhomogeneous perfect fluid mixtures

    CERN Document Server

    Zarate, R D; Zarate, Ruben D.; Quevedo, Hernando

    2004-01-01

    We analyze the compatibility between the geometrodynamics and thermodynamics of a binary mixture of perfect fluids which describe inhomogeneous cosmological models. We generalize the thermodynamic scheme of general relativity to include the chemical potential of the fluid mixture with non-vanishing entropy production. This formalism is then applied to the case of Szekeres and Stephani families of cosmological models. The compatibility conditions turn out to impose symmetry conditions on the cosmological models in such a way that only the limiting case of the Friedmann-Robertson-Walker model remains compatible. This result is an additional indication of the incompatibility between thermodynamics and relativity.

  14. Two-microphone Separation of Speech Mixtures

    DEFF Research Database (Denmark)

    2006-01-01

    Matlab source code for underdetermined separation of instaneous speech mixtures. The algorithm is described in [1] Michael Syskind Pedersen, DeLiang Wang, Jan Larsen and Ulrik Kjems: ''Two-microphone Separation of Speech Mixtures,'' 2006, submitted for journal publoication. See also, [2] Michael...... Syskind Pedersen, DeLiang Wang, Jan Larsen and Ulrik Kjems: ''Overcomplete Blind Source Separation by Combining ICA and Binary Time-Frequency Masking,'' in proceedings of IEEE International workshop on Machine Learning for Signal Processing, pp. 15-20, 2005. All files should be in the same directory. The...

  15. Thermophysical Properties of Fluids and Fluid Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Sengers, Jan V.; Anisimov, Mikhail A.

    2004-05-03

    The major goal of the project was to study the effect of critical fluctuations on the thermophysical properties and phase behavior of fluids and fluid mixtures. Long-range fluctuations appear because of the presence of critical phase transitions. A global theory of critical fluctuations was developed and applied to represent thermodynamic properties and transport properties of molecular fluids and fluid mixtures. In the second phase of the project, the theory was extended to deal with critical fluctuations in complex fluids such as polymer solutions and electrolyte solutions. The theoretical predictions have been confirmed by computer simulations and by light-scattering experiments. Fluctuations in fluids in nonequilibrium states have also been investigated.

  16. Heterogeneous solid mixtures combustion: influence of microstructure

    International Nuclear Information System (INIS)

    A model of solid composite microstructure is developed to predict concentration limits of heterogeneous solid mixture combustion of gasless and small-gas-content systems. The prediction is based on the percolation theory combined with the fractal concept and the Scher-Zallen criterion that postulates that the volume fraction necessary for the onset of percolation is about 16% of the total volume. The validity of the criterion is supported by a set of literature data on concentration limits of combustion for binary mixtures of transition metals and p-block elements such as Zr, Hf, Nb, Ta, Mo, B, C, Si, Al, Ge

  17. Thermodynamic scheme of inhomogeneous perfect fluid mixtures

    International Nuclear Information System (INIS)

    We analyse the compatibility between the geometrodynamics and thermodynamics of a binary mixture of perfect fluids which describe inhomogeneous cosmological models. We generalize the thermodynamic scheme of general relativity to include the chemical potential of the fluid mixture with non-vanishing entropy production. This formalism is then applied to the case of Szekeres and Stephani families of cosmological models. The compatibility conditions turn out to impose symmetry conditions on the cosmological models in such a way that only the limiting case of the Friedmann-Robertson-Walker model remains compatible. This result is an additional indication of the incompatibility between thermodynamics and relativity

  18. On Normal Variance-Mean Mixtures

    CERN Document Server

    Yu, Yaming

    2011-01-01

    Normal variance-mean mixtures encompass a large family of useful distributions such as the generalized hyperbolic distribution, which itself includes the Student t, Laplace, hyperbolic, normal inverse Gaussian, and variance gamma distributions as special cases. We study shape properties of normal variance-mean mixtures, in both the univariate and multivariate cases, and determine conditions for unimodality and log-concavity of the density functions. This leads to a short proof of the unimodality of all generalized hyperbolic densities. We also interpret such results in practical terms and discuss discrete analogues.

  19. COP improvement of refrigerator/freezers, air-conditioners, and heat pumps using nonazeotropic refrigerant mixtures

    Science.gov (United States)

    Westra, Douglas G.

    1993-01-01

    With the February, 1992 announcement by President Bush to move the deadline for outlawing CFC (chloro-fluoro-carbon) refrigerants from the year 2000 to the year 1996, the refrigeration and air-conditioning industries have been accelerating their efforts to find alternative refrigerants. Many of the alternative refrigerants being evaluated require synthetic lubricants, are less efficient, and have toxicity problems. One option to developing new, alternative refrigerants is to combine existing non-CFC refrigerants to form a nonazeotropic mixture, with the concentration optimized for the given application so that system COP (Coefficient Of Performance) may be maintained or even improved. This paper will discuss the dilemma that industry is facing regarding CFC phase-out and the problems associated with CFC alternatives presently under development. A definition of nonazeotropic mixtures will be provided, and the characteristics and COP benefits of nonazeotropic refrigerant mixtures will be explained using thermodynamic principles. Limitations and disadvantages of nonazeotropic mixtures will be discussed, and example systems using such mixtures will be reviewed.

  20. Laminar flame velocity determination for H2-air-steam mixtures using the spherical bomb method

    International Nuclear Information System (INIS)

    In the framework of the new design of nuclear reactor power plant, the hazard due to the presence of hydrogen must be taken into account. More precisely, a mixture of hydrogen, water vapor and air can be formed inside the nuclear power plant building. In order to model correctly the flame propagation in such complicated environment, one of the fundamental input data is the laminar flame velocity of these diluted mixtures. It is needed then to determine the laminar flame velocity of lean hydrogen air flames diluted or not by steam. The present work reports experimental results on the determination of laminar flame velocities of hydrogen - air - diluent mixtures initially at 100 kPa and for 2 different initial temperatures 298 and 353 K. The diluent was water vapor or a mixture containing helium and carbon dioxide. The data obtained in this study are compared with the literature ones. The experimental setup consists of a spherical bomb coupled to a Schlieren system and a high speed camera. The effect of the stretch on the flame velocity is characterized for all the investigated mixtures. Computed laminar flame velocities are obtained using PREMIX and CHEMKIN codes. Two different kinetic mechanisms are used, and the computed values are compared to the experimental ones. (authors)

  1. On-line method to study dynamics of ion adsorption from mixtures of salts in capacitive deionization

    NARCIS (Netherlands)

    Dykstra, J.E.; Dijkstra, J.; Wal, van der A.; Hamelers, H.V.M.; Porada, S.

    2016-01-01

    Capacitive Deionization (CDI) is a water desalination technology that adsorbs ions into two oppositely polarized porous carbon electrodes, under the action of an applied voltage. Here, we introduce a novel method to analyze the effluent concentration of multiple ionic species in mixtures of salt

  2. Multiphase Binary Mixture Flows in Porous Media in a Wide Pressure and Temperature Range Including Critical Conditions

    Science.gov (United States)

    Afanasyev, A.

    2011-12-01

    Multiphase flows in porous media with a transition between sub- and supercritical thermodynamic conditions occur in many natural and technological processes (e.g. in deep regions of geothermal reservoirs where temperature reaches critical point of water or in gas-condensate fields where subject to critical conditions retrograde condensation occurs and even in underground carbon dioxide sequestration processes at high formation pressure). Simulation of these processes is complicated due to degeneration of conservation laws under critical conditions and requires non-classical mathematical models and methods. A new mathematical model is proposed for efficient simulation of binary mixture flows in a wide range of pressures and temperatures that includes critical conditions. The distinctive feature of the model lies in the methodology for mixture properties determination. Transport equations and Darcy law are solved together with calculation of the entropy maximum that is reached in thermodynamic equilibrium and determines mixture composition. To define and solve the problem only one function - mixture thermodynamic potential - is required. Such approach allows determination not only single-phase states and two-phase states of liquid-gas type as in classical models but also two-phase states of liquid-liquid type and three-phase states. The proposed mixture model was implemented in MUFITS (Multiphase Filtration Transport Simulator) code for hydrodynamic simulations. As opposed to classical approaches pressure, enthalpy and composition variables together with fully implicit method and cascade procedure are used. The code is capable of unstructured grids, heterogeneous porous media, relative permeability and capillary pressure dependence on temperature and pressure, multiphase diffusion, optional number of sink and sources, etc. There is an additional module for mixture properties specification. The starting point for the simulation is a cubic equation of state that is

  3. Explorations of soil microbial processes driven by dissolved organic carbon

    NARCIS (Netherlands)

    Straathof, A.L.

    2015-01-01

    Explorations of soil microbial processes driven by dissolved organic carbon Angela L. Straathof June 17, 2015, Wageningen UR ISBN 978-94-6257-327-7 Abstract Dissolved organic carbon (DOC) is a complex, heterogeneous mixture of C compounds which, as

  4. Investigation of interlaminar shear strength in carbon epoxy and carbon epoxy carbon nanotubes using experimental and finite element technique

    Directory of Open Access Journals (Sweden)

    P. Rama Lakshmi

    2012-05-01

    Full Text Available The present study concerns experimental and finite element analysis of carbon epoxy and carbon epoxy carbon nanotube composites to estimate interlaminar shear strength. Mechanical properties such as elastic ratios, thickness are varied for double notched specimen and the corresponding deflections and interlaminar shear strengths are estimated by ANSYS. From simple rule of mixtures, equivalent orthotropic material properties are estimated. These properties are provided as input in ANSYS to generate finite element model. Solid layered element is used to model double notch specimen. To estimate the properties of carbon epoxy carbon nanotube composite, initially finite element model of matrix and carbon nanotube is generated by properties individual material properties of both the materials. From the obtained stretch and stress, the equivalent material property of combined matrix and carbon nanotube is achieved. This property is provided as input in simple rule of mixtures to find out the equivalent orthotropic materials are determined. It is inferred that experiment results are in good agreement with results generated by ANSYS. The superiority of the presence of carbon nanotube in the composite is proved from experimental and finite element technique from the estimated fracture parameters.

  5. Production of Iodine-132 from Irradiated Uranium Tetrafluoride

    International Nuclear Information System (INIS)

    Instead of the metallic uranium or uranium oxides usually used, the authors selected UF4 as the material to be irradiated. The reasons for this choice are as follows: (a) it possesses good thermal and radiolytic stability; (b) it is easily soluble in a solution consisting of concentrated hydrochloric acid and boric acid; (c) the dissolution reaction is gentle and without gas release; (d) the uranium is dissolved as U4+ in a non-oxidizing medium, which permits of selective reduction of the telluric acid added as carrier. The above factors greatly facilitate the process of separating the Te132. The method of separating the Te132 is as follows: (a) dissolution of the UF4 in the medium mentioned above; (b) direct reduction of the telluric acid using SnCl2 followed by filtration; (c) re-dissolution of the Te using concentrated hydrochloric acid and hydrogen peroxide; (d) re-precipitation of the Te in a hydrochloric medium using SnCl2 or SO2, followed by filtration; (e) final dissolution of the Te in concentrated nitric acid. The nitric solution of tellurium, containing no fission products that are not isotopic with Te132, is fixed on an alumina column and the I132 is removed periodically. The fixation of Te182 and the elution of I132 were studied and the chemical and radiochemical purity of the product obtained was verified. This method can be used with relatively large quantities of UF4, which compensates for the poor integral fluxes available in research reactors, such as JEN -1, and thus enables sufficient quantities of I132 - of the order of 0.5 c - to be obtained in establishments lacking high-flux reactors in almost continuous operation or unable to irradiate enriched uranium. (author)

  6. Combinatorial approach for the rapid determination of thermochromic behavior of binary and ternary cholesteric liquid crystalline mixtures.

    Science.gov (United States)

    van der Werff, Louise C; Robinson, Andrea J; Kyratzis, Ilias L

    2012-11-12

    A combinatorial approach was developed for the rapid determination of thermochromic behavior of a large number of binary and ternary sterol based thermochromic liquid crystalline formulations. A binary mixture containing cholesteryl oleyl carbonate and cholesteryl nonanoate, and ternary mixtures also containing a third component, either cholesteryl oleate, cholesteryl benzoate, cholesteryl 2,4-dichlorobenzoate or cholesteryl propionate, were formulated via solvent deposition into a black Teflon coated aluminum 96 well plate. The temperature of the well plate was then varied, and the color appearance of the deposited mixture in each well was recorded. This approach allowed expedient examination of the thermochromic behavior for a large range of liquid crystal formulations. The accuracy of the rapid combinatorial technique was validated on selected thermochromic liquid crystal mixture compositions by comparing well thermochromic output with that observed using UV-vis spectroscopy on material produced in gram quantities. PMID:23072483

  7. Predicting diffusivities in dense fluid mixtures

    Directory of Open Access Journals (Sweden)

    C. DARIVA

    1999-09-01

    Full Text Available In this work the Enskog solution of the Boltzmann equation, as corrected by Speedy, together with the Weeks-Chandler-Andersen (WCA perturbation theory of liquids is employed in correlating and predicting self-diffusivities of dense fluids. Afterwards this theory is used to estimate mutual diffusion coefficients of solutes at infinite dilution in sub and supercritical solvents. We have also investigated the behavior of Fick diffusion coefficients in the proximity of a binary vapor-liquid critical point since this subject is of great interest for extraction purposes. The approach presented here, which makes use of a density and temperature dependent hard-sphere diameter, is shown to be excellent for predicting diffusivities in dense pure fluids and fluid mixtures. The calculations involved highly nonideal mixtures as well as systems with high molecular asymmetry. The predicted diffusivities are in good agreement with the experimental data for the pure and binary systems. The methodology proposed here makes only use of pure component information and density of mixtures. The simple algebraic relations are proposed without any binary adjustable parameters and can be readily used for estimating diffusivities in multicomponent mixtures.

  8. Spinodal decomposition of chemically reactive binary mixtures

    Science.gov (United States)

    Lamorgese, A.; Mauri, R.

    2016-08-01

    We simulate the influence of a reversible isomerization reaction on the phase segregation process occurring after spinodal decomposition of a deeply quenched regular binary mixture, restricting attention to systems wherein material transport occurs solely by diffusion. Our theoretical approach follows a diffuse-interface model of partially miscible binary mixtures wherein the coupling between reaction and diffusion is addressed within the frame of nonequilibrium thermodynamics, leading to a linear dependence of the reaction rate on the chemical affinity. Ultimately, the rate for an elementary reaction depends on the local part of the chemical potential difference since reaction is an inherently local phenomenon. Based on two-dimensional simulation results, we express the competition between segregation and reaction as a function of the Damköhler number. For a phase-separating mixture with components having different physical properties, a skewed phase diagram leads, at large times, to a system converging to a single-phase equilibrium state, corresponding to the absolute minimum of the Gibbs free energy. This conclusion continues to hold for the critical phase separation of an ideally perfectly symmetric binary mixture, where the choice of final equilibrium state at large times depends on the initial mean concentration being slightly larger or less than the critical concentration.

  9. Modeling text with generalizable Gaussian mixtures

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Sigurdsson, Sigurdur; Kolenda, Thomas;

    2000-01-01

    We apply and discuss generalizable Gaussian mixture (GGM) models for text mining. The model automatically adapts model complexity for a given text representation. We show that the generalizability of these models depends on the dimensionality of the representation and the sample size. We discuss...

  10. A structural investigation of ionic liquid mixtures.

    Science.gov (United States)

    Matthews, Richard P; Villar-Garcia, Ignacio J; Weber, Cameron C; Griffith, Jeraime; Cameron, Fiona; Hallett, Jason P; Hunt, Patricia A; Welton, Tom

    2016-03-16

    The structures of mixtures of ionic liquids (ILs) featuring a common 1-butyl-3-methylimidazolium ([C4C1im](+)) cation but different anions have been investigated both experimentally and computationally. (1)H and (13)C NMR of the ILs and their mixtures has been performed both on the undiluted liquids and those diluted by CD2Cl2. These experiments have been complemented by quantum chemical density functional theory calculations and molecular dynamics simulations. These techniques have identified the formation of preferential interactions between H(2) of the imidazolium cation and the most strongly hydrogen bond (H-bond) accepting anion. In addition, a preference for the more weakly H-bond accepting anion to interact above the imidazolium ring through anion-π(+) interactions has been identified. The modelling of these data has identified that the magnitude of these preferences are small, of the order of only a few kJ mol(-1), for all IL mixtures. No clustering of the anions around a specific cation could be observed, indicating that these interactions arise from the reorientation of the cation within a randomly assigned network of anions. π(+)-π(+) stacking of the imidazolium cations was also studied and found to be promoted by ILs with a strong H-bond accepting anion. Stacking interactions are easily disrupted by the introduction of small proportions (accounting for why most IL mixtures exhibit ideal, or nearly ideal, behaviour. PMID:26947103

  11. Multicomponent transport in weakly ionized mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Giovangigli, V [CMAP, CNRS, Ecole Polytechnique, 91128 Palaiseau (France); Graille, B [Laboratoire de Mathematiques, Universite Paris-Sud, 91405, Orsay (France); Magin, T [Center for Turbulence Research, Stanford University, CA 94305 (United States); Massot, M, E-mail: vincent.giovangigli@polytechnique.f [Laboratoire EM2C, Ecole Centrale de Paris, 92295 Chatenay-Malabry (France)

    2010-06-15

    We discuss transport coefficients in weakly ionized mixtures. We investigate the situations of weak and strong magnetic fields as well as electron temperature nonequilibrium. We present in each regime the Boltzmann equations, examples of transport fluxes, the structure of transport linear systems and discuss their solution by efficient iterative techniques. Numerical simulations are presented for partially ionized high-temperature air.

  12. Toxicology of chemical mixtures: International perspective

    NARCIS (Netherlands)

    Feron, V.J.; Cassee, F.R.; Groten, J.P.

    1998-01-01

    This paper reviews major activities outside the United States on human health issues related to chemical mixtures. In Europe an international study group on combination effects has been formed and has started by defining synergism and antagonism. Successful research programs in Europe include the de

  13. 3He-4He II mixtures

    International Nuclear Information System (INIS)

    A theoretical study of the thermodynamic and hydrodynamic properties of 3He-4He II mixtures at temperatures below 250 mK is described. A hydrodynamic model is set up which incorporates mutual friction between the two components. Results of an investigation into the quantitative calculation of the mutual friction are reported. 148 refs.; 34 figs.; 4 tabs

  14. Regularized Finite Mixture Models for Probability Trajectories

    Science.gov (United States)

    Shedden, Kerby; Zucker, Robert A.

    2008-01-01

    Finite mixture models are widely used in the analysis of growth trajectory data to discover subgroups of individuals exhibiting similar patterns of behavior over time. In practice, trajectories are usually modeled as polynomials, which may fail to capture important features of the longitudinal pattern. Focusing on dichotomous response measures, we…

  15. Molecular weight scaling in critical polymer mixtures

    DEFF Research Database (Denmark)

    Gehlsen, M.D.; Rosedale, J.R.; Bates, F.S.; Wignall, G.D.; Hansen, L.; Almdal, K.

    1992-01-01

    Symmetric binary mixtures of partially deuterated polymers were prepared at the critical composition. The segment-segment interaction energy parameter chi(eff) was varied by adjusting the difference in deuterium content DELTA-X(D) between species. Chi(eff) was measured as a function of temperature...

  16. Black carbon estimation in French calcareous soils using chemo-thermal oxidation method

    OpenAIRE

    Caria, G.; Arrouays, D.; Dubromel, E.; Jolivet, C.; Ratié, C.; Bernoux, MARTIAL,; Barthès, Bernard; Brunet, Didier; Grinand, Clovis

    2011-01-01

    We studied the black carbon (BC) content of ca. 405 samples from French topsoil and artificial soil and carbonate mixtures. Our protocol involved three main steps: (i) decarbonation by HCl, (ii) elimination of non-pyrogenic organic carbon in a furnace at 375 degrees C, and (iii) quantification of residual carbon by CHN analysis. BC content increased for calcareous soils according to their carbonates content. Subsequent analyses confirmed the existence of a methodological artefact for BC deter...

  17. Atmospheric pressure plasma treatment of glassy carbon for adhesion improvement

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Mortensen, Henrik Junge; Stenum, Bjarne;

    2007-01-01

    density increased with the plasma treatments. Adhesion test of the treated glassy carbon covered with cured epoxy showed cohesive failure, indicating strong bonding after the treatments. This is in contrast to the adhesion tests of untreated samples where the epoxy readily peeled off the glassy carbon.......Glassy carbon plates were treated with an atmospheric pressure dielectric barrier discharge (DBD). He gas, gas mixtures of He and reactive gases such as O2, CO2 and NH3, Ar gas and Ar/NH3 gas mixture were used as treatment gases. The oxygen and nitrogen contents on the surface as well as defect...

  18. Mars in situ propellants: Carbon monoxide and oxygen ignition experiments

    Science.gov (United States)

    Linne, Diane L.; Roncace, James; Groth, Mary F.

    1990-01-01

    Carbon monoxide and oxygen were tested in a standard spark-torch igniter to identify the ignition characteristics of this potential Mars in situ propellant combination. The ignition profiles were determined as functions of mixture ratio, amount of hydrogen added to the carbon monoxide, and oxygen inlet temperature. The experiments indicated that the carbon monoxide and oxygen combination must have small amounts of hydrogen present to initiate reaction. Once the reaction was started, the combustion continued without the presence of hydrogen. A mixture ratio range was identified where ignition occurred, and this range varied with the oxygen inlet temperature.

  19. Measurement and correlation of critical properties for binary mixtures and ternary mixtures containing gasoline additives

    International Nuclear Information System (INIS)

    Highlights: • A high-pressure view cell was used to measure the critical properties of mixtures. • Three binary mixtures’ and three ternary mixtures’ critical properties were reported. • The experimental data of each system covered the whole mole fraction range. • The critical properties of the ternary mixtures were predicted with the PR–WS model. • Empirical equations were used to correlate the experimental results. - Abstract: The critical properties of three binary mixtures and three ternary mixtures containing gasoline additives (including methanol + 1-propanol, heptane + ethanol, heptane + 1-propanol, methanol + 1-propanol + heptane, methanol + 1-propanol + methyl tert-butyl ether (MTBE), and ethanol + heptane + MTBE) were determined by a high-pressure cell. All the critical lines of binary mixtures belong to the type I described by Scott and van Konynenburg. The system of methanol + 1-propanol showed little non-ideal behavior due to their similar molecular structures. The heptane + ethanol and heptane + 1-propanol systems showed visible non-ideal behavior for their great differences in molecular structure. The Peng–Robinson equation of state combined with the Wong–Sandler mixing rule (PR–WS) was applied to correlate the critical properties of binary mixtures. The critical points of the three ternary mixtures were predicted by the PR–WS model with the binary interaction parameters using the procedure proposed by Heidemann and Khalil. The predicted critical temperatures were in good agreement with the experimental values, while the predicted critical pressures differed from the measured values. The experimental values of binary mixtures were fitted well with the Redlich–Kister equation. The critical properties of ternary mixtures were correlated with the Cibulka’s equation, and the critical surfaces were plotted using the Cibulka’s equations

  20. Method for making thin carbon foam electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Pekala, R.W.; Mayer, S.T.; Kaschmitter, J.L.; Morrison, R.L.

    1999-08-03

    A method for fabricating thin, flat carbon electrodes by infiltrating highly porous carbon papers, membranes, felts, metal fibers/powders, or fabrics with an appropriate carbon foam precursor material is disclosed. The infiltrated carbon paper, for example, is then cured to form a gel-saturated carbon paper, which is subsequently dried and pyrolyzed to form a thin sheet of porous carbon. The material readily stays flat and flexible during curing and pyrolyzing to form thin sheets. Precursor materials include polyacrylonitrile (PAN), polymethylacrylonitrile (PMAN), resorcinol/formaldehyde, catechol/formaldehyde, phenol/formaldehyde, etc., or mixtures thereof. These thin films are ideal for use as high power and energy electrodes in batteries, capacitors, and fuel cells, and are potentially useful for capacitive deionization, filtration and catalysis.

  1. Method for making thin carbon foam electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Pekala, Richard W. (Pleasant Hill, CA); Mayer, Steven T. (San Leandro, CA); Kaschmitter, James L. (Pleasanton, CA); Morrison, Robert L. (Modesto, CA)

    1999-01-01

    A method for fabricating thin, flat carbon electrodes by infiltrating highly porous carbon papers, membranes, felts, metal fibers/powders, or fabrics with an appropriate carbon foam precursor material. The infiltrated carbon paper, for example, is then cured to form a gel-saturated carbon paper, which is subsequently dried and pyrolyzed to form a thin sheet of porous carbon. The material readily stays flat and flexible during curing and pyrolyzing to form thin sheets. Precursor materials include polyacrylonitrile (PAN), polymethylacrylonitrile (PMAN), resorcinol/formaldehyde, catechol/formaldehyde, phenol/formaldehyde, etc., or mixtures thereof. These thin films are ideal for use as high power and energy electrodes in batteries, capacitors, and fuel cells, and are potentially useful for capacitive deionization, filtration and catalysis.

  2. Experiments with Mixtures Designs, Models, and the Analysis of Mixture Data

    CERN Document Server

    Cornell, John A

    2011-01-01

    The most comprehensive, single-volume guide to conducting experiments with mixtures"If one is involved, or heavily interested, in experiments on mixtures of ingredients, one must obtain this book. It is, as was the first edition, the definitive work."-Short Book Reviews (Publication of the International Statistical Institute)"The text contains many examples with worked solutions and with its extensive coverage of the subject matter will prove invaluable to those in the industrial and educational sectors whose work involves the design and analysis of mixture experiments."-Journal of the Royal S

  3. Novel microthermal sensor principle for determining the mixture ratio of binary fluid mixtures using Föppl vortices

    OpenAIRE

    B. Schmitt; Kiefer, C; Schütze, A.

    2015-01-01

    A novel sensor principle for determining binary fluid mixtures of known components is presented, making use of different thermal and rheological properties of the mixture's components. Using a microheater, a heat pulse is introduced in the mixture. The resulting temperature increase depends on the thermal properties of the mixture, allowing determination of the mixture ratio. Placing a bluff body in the fluid channel causes the formation of a stationary pair of vortices behi...

  4. Carbon membranes for efficient water-ethanol separation

    CERN Document Server

    Gravelle, Simon; Joly, Laurent; Ybert, Christophe; Bocquet, Lydéric

    2016-01-01

    We demonstrate, on the basis of molecular dynamics simulations, the possibility of an efficient water-ethanol separation using nanoporous carbon membranes, namely carbon nanotube membranes, nanoporous graphene sheets, and multilayer graphene membranes. While these carbon membranes are in general permeable to both pure liquids, they exhibit a counter-intuitive "self-semi-permeability" to water in the presence of water-ethanol mixtures. This originates in a preferred ethanol adsorption in nanoconfinement that prevents water molecules from entering the carbon nanopores. An osmotic pressure is accordingly expressed across the carbon membranes for the water-ethanol mixture, which agrees with the classic van't Hoff type expression. This suggests a robust and versatile membrane-based separation, built on a pressure-driven reverse-osmosis process across these carbon-based membranes. In particular, the recent development of large-scale 'graphene-oxide' like membranes then opens an avenue for a versatile and efficient ...

  5. Understanding hydrothermal carbonization of mixed feedstocks for waste conversion

    Science.gov (United States)

    Lu, Xiaowei

    Hydrothermal carbonization (HTC) is an environmentally beneficial means to convert waste materials to value-added solid and liquid products with minimal greenhouse gas emission. Research is lacking on understanding the influence of critical process conditions on product formation and environmental implication associated with HTC of waste streams. This work was conducted to determine how reaction conditions and heterogeneous compound mixtures (representative of municipal wastes) influence hydrothermal carbonization processes. The specific experiments include: (1) determine how carbonization product properties are manipulated by controlling feedstock composition, process conditions, and catalyst addition; (2) determine if carbonization of heterogeneous mixtures follows similar pathways as that with pure feedstocks; and (3) evaluate and compare the carbon and energy-related implications associated with carbonization products with those associated with other common waste management processes for solid waste.

  6. Penetration Depth of Microwave into the Mixture of Goethite with Graphite Estimated by Permittivity and Conductivity

    Science.gov (United States)

    Kawahira, Keita; Saito, Youichi; Yoshikawa, Noboru; Todoroki, Hidekazu; Taniguchi, Shoji

    2013-11-01

    A study has been conducted to understand the penetration behavior of microwave into the mixture of goethite with carbon (C) aiming at providing an appropriate guidance to dehydrate the substances with hydroxides occasionally contained in industrial sludge. At first, it was observed that microwave could not sufficiently penetrate into the specimen with C/goethite molar ratios greater than 2, giving incomplete dehydration. To understand the penetration behavior of microwave, permittivity and conductivity were measured. Permittivity measurements were successfully made below 9 vol pct C. For carbon content greater than 8.56 vol pct C, the conductivity of the mixture abruptly increased by four orders of magnitude because of the occurrence of the conductivity percolation. Above 13.7 vol pct C close to an inflection point approximating 10 vol pct C, the mixture became sufficiently conductive. Transition from dielectric to conductive behavior occurred between 8.56 and 13.7 vol pct C. The Generalized Effective Medium approximation could satisfactorily express the variation of the conductivity values in the whole range of vol pct C measured. The penetration depth of microwave was determined by the above two measurements. It was found that penetration depth decreased with the increasing vol pct of C contained in the mixture specimen. Finally, guidance could be provided as for the blend ratio of C to treated material along with the size of a briquette or a pellet referring to the obtained relation between penetration depth and vol pct of C. Furthermore, it was proved that the numerical simulation was quite helpful to predict how microwave behaves in the mixture under given conditions.

  7. Thermodiffusion in binary and ternary nonpolar hydrocarbon + alcohol mixtures

    Science.gov (United States)

    Eslamian, Morteza; Saghir, M. Ziad

    2012-12-01

    Thermodiffusion in complex mixtures, such as associating, molten metal, and polymer mixtures is difficult to model usually owing to the occurrence of a sign change in the thermodiffusion coefficient when the mixture concentration and temperature change. A mixture comprised of a nonpolar hydrocarbon and an alcohol is a complex and highly non-ideal mixture. In this paper an existing binary non-equilibrium thermodynamics model (Eslamian and Saghir, Physical Review E 80, 061201, 2009) developed for aqueous mixtures of alcohols is examined against the experimental data of binary nonpolar hydrocarbon and alcohol mixtures. For ternary mixtures, non-equilibrium thermodynamic expressions developed by the authors for aqueous mixtures of alcohols (Eslamian and Saghir, Canadian Journal of Chemical Engineering, DOI 10.1002/cjce.20581) is used to predict thermodiffusion coefficients of ternary nonpolar hydrocarbon and alcohol mixtures. The rationale behind the sign change is elucidated and attributed to an anomalous change in the molecular structure and therefore viscosity of such mixtures. Model predictions of thermodiffusion coefficients of binary mixtures predict a sign change consistent with the experimental data although the model is still too primitive to capture all structural complexities. For instance, in the methanol-benzene mixture where the model predictions are poorest, the viscosity data show that when concentration varies, the mixture's molecular structure experiences a severe change twice, the first major change leading to a maximum in the thermodiffusion coefficient, whereas the second change causes a sign change.

  8. Thermogravimetric Analysis of Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Arepalli, Sivram; Nikolaev, Pavel; Gorelik, Olga

    2010-01-01

    An improved protocol for thermogravimetric analysis (TGA) of samples of single-wall carbon nanotube (SWCNT) material has been developed to increase the degree of consistency among results so that meaningful comparisons can be made among different samples. This improved TGA protocol is suitable for incorporation into the protocol for characterization of carbon nanotube material. In most cases, TGA of carbon nanotube materials is performed in gas mixtures that contain oxygen at various concentrations. The improved protocol is summarized.

  9. The optimization of concrete mixtures for use in highway applications

    Science.gov (United States)

    Moini, Mohamadreza

    Portland cement concrete is most used commodity in the world after water. Major part of civil and transportation infrastructure including bridges, roadway pavements, dams, and buildings is made of concrete. In addition to this, concrete durability is often of major concerns. In 2013 American Society of Civil Engineers (ASCE) estimated that an annual investment of 170 billion on roads and 20.5 billion for bridges is needed on an annual basis to substantially improve the condition of infrastructure. Same article reports that one-third of America's major roads are in poor or mediocre condition [1]. However, portland cement production is recognized with approximately one cubic meter of carbon dioxide emission. Indeed, the proper and systematic design of concrete mixtures for highway applications is essential as concrete pavements represent up to 60% of interstate highway systems with heavier traffic loads. Combined principles of material science and engineering can provide adequate methods and tools to facilitate the concrete design and improve the existing specifications. In the same manner, the durability must be addressed in the design and enhancement of long-term performance. Concrete used for highway pavement applications has low cement content and can be placed at low slump. However, further reduction of cement content (e.g., versus current specifications of Wisconsin Department of Transportation to 315-338 kg/m 3 (530-570 lb/yd3) for mainstream concrete pavements and 335 kg/m3 (565 lb/yd3) for bridge substructure and superstructures) requires delicate design of the mixture to maintain the expected workability, overall performance, and long-term durability in the field. The design includes, but not limited to optimization of aggregates, supplementary cementitious materials (SCMs), chemical and air-entraining admixtures. This research investigated various theoretical and experimental methods of aggregate optimization applicable for the reduction of cement content

  10. Molecular simulation of multi-component adsorption processes related to carbon capture in a high surface area, disordered activated carbon

    OpenAIRE

    Di Biase, Emanuela; Sarkisov, Lev

    2015-01-01

    We employ a previously developed model of a high surface area activated carbon, based on a random packing of small fragments of a carbon sheet, functionalized with hydroxyl surface groups, to explore adsorption of water and multicomponent mixtures under conditions representing typical carbon capture processes. Adsorption of water is initialized and proceeds through the growth of clusters around the surface groups, in a process predominantly governed by hydrogen bond interactions. In contrast,...

  11. Embedded Electronic Nose for VOC Mixture Analysis

    International Nuclear Information System (INIS)

    This paper details the work done towards a low cost, small size, portable embedded electronic nose (e-nose) and its application for analysis of different VOC mixtures. The sensor array is composed of commercially available metal oxide semiconductor sensors by Figaro. The embedded E-nose consists of an ADuC831 and has an RS 232 interface for Desktop PC for higher level data collection and NN training. The ESP tool with database facility and multilayer perceptron neural network (MLP NN) is employed to interface the embedded hardware and to process the electronic nose signals before being classified. The use of embedded e-nose for the quantification of VOCs in mixtures is investigated.

  12. Quantum state smoothing for classical mixtures

    CERN Document Server

    Tan, D; Mølmer, K; Murch, K W

    2016-01-01

    In quantum mechanics, wave functions and density matrices represent our knowledge about a quantum system and give probabilities for the outcomes of measurements. If the combined dynamics and measurements on a system lead to a density matrix $\\rho(t)$ with only diagonal elements in a given basis $\\{|n\\rangle\\}$, it may be treated as a classical mixture, i.e., a system which randomly occupies the basis states $|n\\rangle$ with probabilities $\\rho_{nn}(t)$. Fully equivalent to so-called smoothing in classical probability theory, subsequent probing of the occupation of the states $|n\\rangle$ improves our ability to retrodict what was the outcome of a projective state measurement at time $t$. Here, we show with experiments on a superconducting qubit that the smoothed probabilities do not, in the same way as the diagonal elements of $\\rho$, permit a classical mixture interpretation of the state of the system at the past time $t$.

  13. The Supervised Learning Gaussian Mixture Model

    Institute of Scientific and Technical Information of China (English)

    马继涌; 高文

    1998-01-01

    The traditional Gaussian Mixture Model(GMM)for pattern recognition is an unsupervised learning method.The parameters in the model are derived only by the training samples in one class without taking into account the effect of sample distributions of other classes,hence,its recognition accuracy is not ideal sometimes.This paper introduces an approach for estimating the parameters in GMM in a supervising way.The Supervised Learning Gaussian Mixture Model(SLGMM)improves the recognition accuracy of the GMM.An experimental example has shown its effectiveness.The experimental results have shown that the recognition accuracy derived by the approach is higher than those obtained by the Vector Quantization(VQ)approach,the Radial Basis Function (RBF) network model,the Learning Vector Quantization (LVQ) approach and the GMM.In addition,the training time of the approach is less than that of Multilayer Perceptrom(MLP).

  14. Radio thermoluminescence of highly elastic polymer mixtures

    International Nuclear Information System (INIS)

    Modification of polymers by mixing with other polymers improves their electro physical and physical-mechanical properties. Under this mode modification is observed as critical phenomena in the properties that are associated with the interfacial structure of the components, the relaxation of internal connections and changing the degree of homogenization. Depending on the choice of the same polymer as a matrix or modifier may significantly distinguish properties of the composition. One of the most reliable methods of studying of the process of component compatibility of polymer mixtures are radio thermoluminescence (RTL). It is known that heterogeneous polymers and polymer mixtures are characterized by having two or more glass transition temperatures (Tc). On radiation curve of RTL is observed ρ - maximums, corresponding to each of the components.

  15. Probabilistic Discrete Mixtures Colour Texture Models

    Czech Academy of Sciences Publication Activity Database

    Haindl, Michal; Havlíček, Vojtěch; Grim, Jiří

    2008-01-01

    Roč. 2008, č. 5197 (2008), s. 675-682. ISSN 0302-9743. [Iberoamerican Congress on Pattern Recognition /13./. Havana, 09.092008-12.09.2008] R&D Projects: GA AV ČR 1ET400750407; GA MŠk 1M0572; GA ČR GA102/07/1594; GA ČR GA102/08/0593 Grant ostatní: GA MŠk(CZ) 2C06019 Institutional research plan: CEZ:AV0Z10750506 Keywords : Discrete distribution mixtures * EM algorithm * texture modeling Subject RIV: BD - Theory of Information http:// library .utia.cas.cz/separaty/2008/RO/haindl-havlicek-grim-probabilistic%20discrete%20mixtures%20colour%20texture%20models.pdf

  16. Supervised and Unsupervised Classification Using Mixture Models

    Science.gov (United States)

    Girard, S.; Saracco, J.

    2016-05-01

    This chapter is dedicated to model-based supervised and unsupervised classification. Probability distributions are defined over possible labels as well as over the observations given the labels. To this end, the basic tools are the mixture models. This methodology yields a posterior distribution over the labels given the observations which allows to quantify the uncertainty of the classification. The role of Gaussian mixture models is emphasized leading to Linear Discriminant Analysis and Quadratic Discriminant Analysis methods. Some links with Fisher Discriminant Analysis and logistic regression are also established. The Expectation-Maximization algorithm is introduced and compared to the K-means clustering method. The methods are illustrated both on simulated datasets as well as on real datasets using the R software.

  17. Heterogeneity in multistage carcinogenesis and mixture modeling

    Directory of Open Access Journals (Sweden)

    Morgenthaler Stephan

    2008-07-01

    Full Text Available Abstract Carcinogenesis is commonly described as a multistage process, in which stem cells are transformed into cancer cells via a series of mutations. In this article, we consider extensions of the multistage carcinogenesis model by mixture modeling. This approach allows us to describe population heterogeneity in a biologically meaningful way. We focus on finite mixture models, for which we prove identifiability. These models are applied to human lung cancer data from several birth cohorts. Maximum likelihood estimation does not perform well in this application due to the heavy censoring in our data. We thus use analytic graduation instead. Very good fits are achieved for models that combine a small high risk group with a large group that is quasi immune.

  18. Sum of Bernoulli Mixtures: Beyond Conditional Independence

    Directory of Open Access Journals (Sweden)

    Taehan Bae

    2014-01-01

    Full Text Available We consider the distribution of the sum of Bernoulli mixtures under a general dependence structure. The level of dependence is measured in terms of a limiting conditional correlation between two of the Bernoulli random variables. The conditioning event is that the mixing random variable is larger than a threshold and the limit is with respect to the threshold tending to one. The large-sample distribution of the empirical frequency and its use in approximating the risk measures, value at risk and conditional tail expectation, are presented for a new class of models which we call double mixtures. Several illustrative examples with a Beta mixing distribution, are given. As well, some data from the area of credit risk are fit with the models, and comparisons are made between the new models and also the classical Beta-binomial model.

  19. Tails of correlation mixtures of elliptical copulas

    CERN Document Server

    Manner, Hans

    2009-01-01

    Correlation mixtures of elliptical copulas arise when the correlation parameter is driven itself by a latent random process. For such copulas, both penultimate and asymptotic tail dependence are much larger than for ordinary elliptical copulas with the same unconditional correlation. Furthermore, for Gaussian and Student t-copulas, tail dependence at sub-asymptotic levels is generally larger than in the limit, which can have serious consequences for estimation and evaluation of extreme risk. Finally, although correlation mixtures of Gaussian copulas inherit the property of asymptotic independence, at the same time they fall in the newly defined category of near asymptotic dependence. The consequences of these findings for modeling are assessed by means of a simulation study and a case study involving financial time series.

  20. Polydispersity effects in colloid-polymer mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Liddle, S M; Poon, W C K [SUPA and School of Physics and Astronomy, The University of Edinburgh, Kings Buildings, Mayfield Road, Edinburgh EH9 3JZ (United Kingdom); Narayanan, T, E-mail: S.Liddle@ed.ac.uk, E-mail: narayan@esrf.fr, E-mail: w.poon@ed.ac.uk [European Synchrotron Radiation Facility, F-38043 Grenoble Cedex (France)

    2011-05-18

    We study phase separation and transient gelation experimentally in a mixture consisting of polydisperse colloids (polydispersity: {approx} 6%) and non-adsorbing polymers, where the ratio of the average size of the polymer to that of the colloid is {approx} 0.062. Unlike what has been reported previously for mixtures with somewhat lower colloid polydispersity ({approx} 5%), the addition of polymers does not expand the fluid-solid coexistence region. Instead, we find a region of fluid-solid coexistence which has an approximately constant width but an unexpected re-entrant shape. We detect the presence of a metastable gas-liquid binodal, which gives rise to two-stepped crystallization kinetics that can be rationalized as the effect of fractionation. Finally, we find that the separation into multiple coexisting solid phases at high colloid volume fractions predicted by equilibrium statistical mechanics is kinetically suppressed before the system reaches dynamical arrest.