WorldWideScience

Sample records for rare gas solids

  1. Excitons in the rare gas solids

    International Nuclear Information System (INIS)

    1988-01-01

    Excitons play a prominent role in the chemistry and physics of condensed matter. Excitons in the rare gas solids, the prototypical van der Waals insulators, will be the focus of the remainder of this report. The goal here is to investigate the controversies surrounding the description of excitons in insulators and, therefore the simplest class of these solids, namely the rare gas solids, is chosen as the exemplary system. Specific problems associated with molecular crystals are, therefore, avoided and only the salient features of excitons are thus considered. 47 refs., 9 figs., 4 tabs

  2. Anomalous low-temperature desorption from preirradiated rare gas solids

    International Nuclear Information System (INIS)

    Savchenko, E.V.; Gumenchuk, G.B.; Yurtaeva, E.M.; Belov, A.G.; Khyzhniy, I.V.; Frankowski, M.; Beyer, M.K.; Smith-Gicklhorn, A.M.; Ponomaryov, A.N.; Bondybey, V.E.

    2005-01-01

    The role for the exciton-induced defects in the stimulation of anomalous low-temperature desorption of the own lattice atoms from solid Ar and Ne preirradiated by an electron beam is studied. The free electrons from shallow traps-structural defects-was monitored by the measurements of a yield of the thermally induced exoelectron emission (TSEE). The reaction of recombination of self-trapped holes with electrons is considered as a source of energy needed for the desorption of atoms from the surface of preirradiated solids. A key part of the exciton-induced defects in the phenomenon observed is demonstrated

  3. Observation of surface excitons in rare gas solids

    International Nuclear Information System (INIS)

    Saile, V.; Skibowski, M.; Steinmann, W.; Guertler, P.; Koch, E.E.; Kozevnikov, A.

    1976-04-01

    Evidence is obtained for the excitation of surface excitons in solid Ar, Kr and Xe in optical transmission and reflection experiments using synchrotron radiation. They are located at photon energies ranging from 0.6 eV for Ar to 0.1 eV for Xe below the corresponding bulk excitons excited from the valence bands. Their halfwidths (20-50 MeV) is less than half the values found for the bulk excitons. Some are split by an amount considerably smaller than the spin orbit splitting of the valence bands. (orig.) [de

  4. Mean free path of electrons in rare gas solids

    International Nuclear Information System (INIS)

    Schwentner, N.

    1976-07-01

    The energy distribution of photoelectrons of solid Ar, Kr and Xe films with thickness between 10 A and 300 A have been measured in the photon energy range 10 eV to 30 eV using the synchrotron radiation of DESY. By varying the photon energy and the film thickness the dependence of the electron-electron scattering length on the electron kinetic energy has been determined. The mean free path for inelastic electron-electron scattering decreases monotonically from values of the order of 1.000 A at the scattering threshold to values between 1 A and 5 A for electron energies 10 eV above threshold. The observed energy dependence can be understood by a simplified bandstructure and a scattering probability described by a product of density of states. The threshold energy for electron-electron scattering lies between twice the energy of the n = 1 excitons and the sum of bandgap and exciton energy. (HK) [de

  5. Term value/band-gap energy correlations for solid rare gas excitons

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    Term value/ionization energy correlation algorithms have proven to be of considerable utility in the assignment of atomic and molecular Rydberg states. Many examples of empirical term value/ionization energy correlations are known for diverse classes of atoms and molecules. The purpose of this paper is to demonstrate that similar correlations are also obtained for excitons in rare gas solids

  6. Photoemission from excited states in rare gas solids by combining synchrotronradiation with a laser

    International Nuclear Information System (INIS)

    Bernstorff, S.

    1984-09-01

    A new spectroscopic method has been developed to study excited states in rare gas solids: Excitons and conductionband-states are populated by synchrotron radiation (photon energy hw SR =5 - 30 eV). Subsequently electrons from these bound or conduction band-states are excited above the vacuum level of the solid by a pulsed dye laser (hw L =1.9 - 3.7 eV). This experimental technique was applied to solid Xe, Kr, Ar and Ne. (orig./GSCH)

  7. Radiation-induced transformations of isolated organic molecules in solid rare gas matrices

    International Nuclear Information System (INIS)

    Feldman, V.I.

    1998-01-01

    Complete text of publication follows. The studies of radiation-chemical behaviour of isolated organic molecules in rigid inert media are of considerable interest for radiation chemistry and general structural chemistry. Previous efforts were limited to the ESR studies of radicals resulting from some small hydrocarbon molecules in frozen rare gas solutions. Recently, we developed an approach to the radiation chemistry of isolated organic molecules using classic matrix isolation procedure for sample preparation and a combination of ESR and IR spectroscopy for characterization of paramagnetic and diamagnetic species resulting form electron irradiation or organic molecules in solid rare gas matrices at 10-15 K. The results obtained reveal high efficiency of energy transfer from rare gas matrix to organic molecules. The total radiation-chemical yields of degradation of organic molecules in argon and xenon matrices were measured directly by IR spectroscopy. The studies of the effect of electron scavengers on the radiolysis of organic molecules in solid rare gases show that the main primary process is positive hole transfer from matrix to additive molecule. ESR spectra of a number of radical cations (alkanes, ethers, arenes) were first characterized in a low-disturbing environment. It was found that the electronic characteristics (IP, polarizability) of the matrix used had crucial effect on trapping and degradation of primary organic radical cations. Using matrices with various IP provides an unique possibility to examine the chemical meaning of excess energy resulting from exothermic positive hole transfer, that is, to follow the fate of excited cations in condensed phase

  8. Dislocation Structure and Mobility in Hcp Rare-Gas Solids: Quantum versus Classical

    Directory of Open Access Journals (Sweden)

    Santiago Sempere

    2018-01-01

    Full Text Available We study the structural and mobility properties of edge dislocations in rare-gas crystals with the hexagonal close-packed (hcp structure by using classical simulation techniques. Our results are discussed in the light of recent experimental and theoretical studies on hcp 4 He, an archetypal quantum crystal. According to our simulations classical hcp rare-gas crystals present a strong tendency towards dislocation dissociation into Shockley partials in the basal plane, similarly to what is observed in solid helium. This is due to the presence of a low-energy metastable stacking fault, of the order of 0.1 mJ/m 2 , that can get further reduced by quantum nuclear effects. We compute the minimum shear stress that induces glide of dislocations within the hcp basal plane at zero temperature, namely, the Peierls stress, and find a characteristic value of the order of 1 MPa. This threshold value is similar to the Peierls stress reported for metallic hcp solids (Zr and Cd but orders of magnitude larger than the one estimated for solid helium. We find, however, that in contrast to classical hcp metals but in analogy to solid helium, glide of edge dislocations can be thermally activated at very low temperatures, T∼10 K, in the absence of any applied shear stress.

  9. Prospects of Optical Single Atom Detection in Noble Gas Solids for Measurements of Rare Nuclear Reactions

    Science.gov (United States)

    Singh, Jaideep; Bailey, Kevin G.; Lu, Zheng-Tian; Mueller, Peter; O'Connor, Thomas P.; Xu, Chen-Yu; Tang, Xiaodong

    2013-04-01

    Optical detection of single atoms captured in solid noble gas matrices provides an alternative technique to study rare nuclear reactions relevant to nuclear astrophysics. I will describe the prospects of applying this approach for cross section measurements of the ^22Ne,,),25Mg reaction, which is the crucial neutron source for the weak s process inside of massive stars. Noble gas solids are a promising medium for the capture, detection, and manipulation of atoms and nuclear spins. They provide stable and chemically inert confinement for a wide variety of guest species. Because noble gas solids are transparent at optical wavelengths, the guest atoms can be probed using lasers. We have observed that ytterbium in solid neon exhibits intersystem crossing (ISC) which results in a strong green fluorescence (546 nm) under excitation with blue light (389 nm). Several groups have observed ISC in many other guest-host pairs, notably magnesium in krypton. Because of the large wavelength separation of the excitation light and fluorescence light, optical detection of individual embedded guest atoms is feasible. This work is supported by DOE, Office of Nuclear Physics, under contract DE-AC02-06CH11357.

  10. Origin of melting point depression for rare gas solids confined in carbon pores

    International Nuclear Information System (INIS)

    Morishige, Kunimitsu; Kataoka, Takaaki

    2015-01-01

    To obtain insights into the mechanism of the melting-point depression of rare gas solids confined in crystalline carbon pores, we examined the freezing and melting behavior of Xe and Ar confined to the crystalline pores of ordered mesoporous carbons as well as compressed exfoliated graphite compared to the amorphous pores of ordered mesoporous silicas, by means of X-ray diffraction. For the Xe and Ar confined to the crystalline carbon pores, there was no appreciable thermal hysteresis between freezing and melting. Furthermore, the position of the main diffraction peak did not change appreciably on freezing and melting. This strongly suggests that the liquids confined in the carbon pores form a multilayered structure parallel to the smooth walls. For the Xe and Ar confined to the amorphous silica pores, on the other hand, the position of the main diffraction peak shifted into higher scattering angle on freezing suggested that the density of the confined solid is distinctly larger than for the confined liquid. Using compressed exfoliated graphite with carbon walls of higher crystallinity, we observed that three-dimensional (3D) microcrystals of Xe confined in the slit-shaped pores melted to leave the unmelted bilayers on the pore walls below the bulk triple point. The lattice spacing of the 3D microcrystals confined is larger by ∼0.7% than that of the bilayer next to the pore walls in the vicinity of the melting point

  11. Effect of molecular structure on fragmentation of isolated organic molecules in solid rare gas matrices

    International Nuclear Information System (INIS)

    Kobzarenko, A.V.; Sukhov, F.F.; Orlov, A.Yu.; Kovalev, G.V.; Baranova, I.A.; Feldman, V.I.

    2012-01-01

    The effect of excess energy on the primary radical cations of bifunctional carbonyl compounds and aliphatic alkynes was simulated by matrix isolation method using rare gas matrices with various ionization potentials. The formation of fragmentation products was monitored by EPR and FTIR spectroscopy. It was shown that the radical cations of bifunctional compounds (CH 3 OCH 2 COCH 3 and CH 3 COCOCH 3 ) dissociated effectively yielding · CH 3 radicals upon irradiation in solid argon matrix at T≤16 K. In addition to isolated methyl radicals, the radical pairs consisting of two methyl radicals separated by two CO molecules were detected in the case of diacetyl. The probability of fragmentation decreases with the decreasing excess energy by switching from Ar to Xe. In general, bifunctional molecules were found to be less stable to “hot” ionic fragmentation in low-temperature solids in comparison with simple prototype compounds. In the case of alkynes of the R--C≡CH type, a noticeable yield of fragmentation products was observed when R=–C(CH 3 ) 3 , but it was negligible for R=–CH 3 . The mechanisms of “hot” reactions and excess energy relaxation are discussed. - Highlights: ► Radiolysis of bifunctional organic compounds and alkynes. ► Dependence of “hot” fragmentation probability from molecular structure. ► Ions of bifunctional compounds are less stable than those of monofunctional ones. ► Alkynes are rather stable to “hot” fragmentation.

  12. Origin of melting point depression for rare gas solids confined in carbon pores

    Energy Technology Data Exchange (ETDEWEB)

    Morishige, Kunimitsu, E-mail: morishi@chem.ous.ac.jp; Kataoka, Takaaki [Department of Chemistry, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama 700-0005 (Japan)

    2015-07-21

    To obtain insights into the mechanism of the melting-point depression of rare gas solids confined in crystalline carbon pores, we examined the freezing and melting behavior of Xe and Ar confined to the crystalline pores of ordered mesoporous carbons as well as compressed exfoliated graphite compared to the amorphous pores of ordered mesoporous silicas, by means of X-ray diffraction. For the Xe and Ar confined to the crystalline carbon pores, there was no appreciable thermal hysteresis between freezing and melting. Furthermore, the position of the main diffraction peak did not change appreciably on freezing and melting. This strongly suggests that the liquids confined in the carbon pores form a multilayered structure parallel to the smooth walls. For the Xe and Ar confined to the amorphous silica pores, on the other hand, the position of the main diffraction peak shifted into higher scattering angle on freezing suggested that the density of the confined solid is distinctly larger than for the confined liquid. Using compressed exfoliated graphite with carbon walls of higher crystallinity, we observed that three-dimensional (3D) microcrystals of Xe confined in the slit-shaped pores melted to leave the unmelted bilayers on the pore walls below the bulk triple point. The lattice spacing of the 3D microcrystals confined is larger by ∼0.7% than that of the bilayer next to the pore walls in the vicinity of the melting point.

  13. EPR investigation of electronic excitations in rare gas solids (Review Article)

    Science.gov (United States)

    Zhitnikov, R. A.; Dmitriev, Yu. A.

    1998-10-01

    The methods are described for producing unstable paramagnetic excited states in rare gas cryocrystals Ne, Ar, Kr, and Xe through the trapping, in the cryocrystals growing from the gas phase, the products of the gas discharge taking place in the same or other rare gas. The paper presents a technique and results of an observation and investigation of excited states in rare gas cryocrystals with electron paramagnetic resonance (EPR). The discovered unstable paramagnetic centers are interpreted as being local metastable excited np5(n+1)s atomic-type states in rare gas cryocrystals which are subject to the action of the anisotropic electric field resulted from the crystal surroundings distorted by the center. An account is given of the mechanisms for formation of observed paramagnetic excited states in cryocrystals which arise owing to the excitation energy of the metastable 3P2 atoms of Ne, Ar, Kr, Xe and He 23S1 and 21S0 atoms that form in the discharge in an appropriate gas and trap in the growing cryocrystal.

  14. Diffusion of gases in solids: rare gas diffusion in solids; tritium diffusion in fission and fusion reactor metals. Final report

    International Nuclear Information System (INIS)

    Abraham, P.M.; Chandra, D.; Mintz, J.M.; Elleman, T.S.; Verghese, K.

    1976-01-01

    Major results of tritium and rare gas diffusion research conducted under the contract are summarized. The materials studied were austenitic stainless steels, Zircaloy, and niobium. In all three of the metal systems investigated, tritium release rates were found to be inhibited by surface oxide films. The effective diffusion coefficients that control tritium release from surface films on Zircaloy and niobium were determined to be eight to ten orders of magnitude lower than the bulk diffusion coefficients. A rapid component of diffusion due to grain boundaries was identified in stainless steels. The grain boundary diffusion coefficient was determined to be about six orders of magnitude greater than the bulk diffusion coefficient for tritium in stainless steel. In Zircaloy clad fuel pins, the permeation rate of tritium through the cladding is rate-limited by the extremely slow diffusion rate in the surface films. Tritium diffusion rates through surface oxide films on niobium appear to be controlled by cracks in the surface films at temperatures up to 600 0 C. Beyond 600 0 C, the cracks appear to heal, thereby increasing the activation energy for diffusion through the oxide film. The steady-state diffusion of tritium in a fusion reactor blanket has been evaluated in order to calculate the equilibrium tritium transport rate, approximate time to equilibrium, and tritium inventory in various regions of the reactor blanket as a function of selected blanket parameters. Values for these quantities have been tabulated

  15. Effect of molecular structure on fragmentation of isolated organic molecules in solid rare gas matrices

    International Nuclear Information System (INIS)

    Kobrazenko, A.V.; Sukhov, F.F.; Orlov, A.Yu.; Kovalev, G.V.; Baranova, I.A.; Feldman, V.I.

    2011-01-01

    Complete text of publication follows. Elucidation of high-energy reaction pathways in the condensed phase is an important issue for basic understanding of the radiation stability of complex organic molecules. As was shown previously, organic radical cations (RC) may undergo fragmentation or rearrangement in solid matrices due to excess energy. The probability of this process depends on both ionization potential (IP) of the molecule and molecular structure. In the present work we have studied the role of 'hot' ionic reaction channels for RC of some bifunctional compounds and alkynes. The effect of excess energy was simulated by matrix isolation method as described in detail earlier. The formation of fragmentation products was monitored by EPR and FTIR spectroscopy. In the present work it was shown that the RC of bifunctional compounds (CH 3 OCH 2 COCH 3 , CH 3 CO(CH 2 ) n COCH 3 , n 0/2) dissociated efficiently producing · CH 3 radicals upon irradiation in solid argon matrix at T ≤ 16 K. The probability of fragmentation decreases with decrease of excess energy by switching from Ar to Xe. It is worth noting that acetone RC does not show fragmentation under these conditions. Thus, bifunctional molecules were found to be less stable to 'hot' ionic fragmentation in low-temperature solids in comparison with simple prototype carbonyl compounds. In the case of alkynes of the R-C ≡ CH type, a noticeable yield of fragmentation products was observed when R = -C(CH 3 ) 3 , but it was negligible for R = -CH 3 . It means that the presence of triple bond stabilizes the molecular skeleton of linear alkynes toward 'hot' fragmentation, similarly as it was shown for alkenes. The mechanisms of 'hot' reactions and excess energy relaxation are discussed. This work was supported by the Russian Foundation for Basic Research (project 09-03-00848a).

  16. Multiplicity dependence of matrix-induced frequency shifts for atomic transitions of the group 12 metals in rare gas solids

    International Nuclear Information System (INIS)

    Laursen, S.L.; Cartland, H.E.

    1991-01-01

    Atomic resonances of the group 12 metal atoms, Hg, Cd, and Zn, undergo frequency shifts from the gas phase atomic line when trapped in rare gas matrices of Ar, Kr, and Xe at 12 K. As expected, the shifts are approximately linear in polarizability of the rare gas, but the slope of this line depends on whether the transition in question is 1 P 1 left-arrow 1 S 0 or 3 P 1 left-arrow 1 S 0 . Thus the matrix-induced frequency shift is dependent on the singlet or triplet nature of the excited state as well as on the matrix material. This dependence on multiplicity is discussed in terms of interactions between the excited-state atomic orbitals and the matrix. The results are compared to matrix studies of other metals and to related gas-phase work on diatomic van der Waals complexes of group 12 metals with rare gases

  17. Refined potentials for rare gas atom adsorption on rare gas and alkali-halide surfaces

    Science.gov (United States)

    Wilson, J. W.; Heinbockel, J. H.; Outlaw, R. A.

    1985-01-01

    The utilization of models of interatomic potential for physical interaction to estimate the long range attractive potential for rare gases and ions is discussed. The long range attractive force is calculated in terms of the atomic dispersion properties. A data base of atomic dispersion parameters for rare gas atoms, alkali ion, and halogen ions is applied to the study of the repulsive core; the procedure for evaluating the repulsive core of ion interactions is described. The interaction of rare gas atoms on ideal rare gas solid and alkali-halide surfaces is analyzed; zero coverage absorption potentials are derived.

  18. Photochemistry in rare gas clusters

    International Nuclear Information System (INIS)

    Moeller, T.; Haeften, K. von; Pietrowski, R. von

    1999-01-01

    In this contribution photochemical processes in pure rare gas clusters will be discussed. The relaxation dynamics of electronically excited He clusters is investigated with luminescence spectroscopy. After electronic excitation of He clusters many sharp lines are observed in the visible and infrared spectral range which can be attributed to He atoms and molecules desorbing from the cluster. It turns out that the desorption of electronically excited He atoms and molecules is an important decay channel. The findings for He clusters are compared with results for Ar clusters. While desorption of electronically excited He atoms is observed for all clusters containing up to several thousand atoms a corresponding process in Ar clusters is only observed for very small clusters (N<10). (orig.)

  19. Photochemistry in rare gas clusters

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, T.; Haeften, K. von; Pietrowski, R. von [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Hamburger Synchrotronstrahlungslabor; Laarman, T. [Universitaet Hamburg, II. Institut fuer Experimentalphysik, Luruper Chaussee 149, D-22761 Hamburg (Germany)

    1999-12-01

    In this contribution photochemical processes in pure rare gas clusters will be discussed. The relaxation dynamics of electronically excited He clusters is investigated with luminescence spectroscopy. After electronic excitation of He clusters many sharp lines are observed in the visible and infrared spectral range which can be attributed to He atoms and molecules desorbing from the cluster. It turns out that the desorption of electronically excited He atoms and molecules is an important decay channel. The findings for He clusters are compared with results for Ar clusters. While desorption of electronically excited He atoms is observed for all clusters containing up to several thousand atoms a corresponding process in Ar clusters is only observed for very small clusters (N<10). (orig.)

  20. Theory of diffusion of rare gases in solids

    International Nuclear Information System (INIS)

    Lidiard, A.B.

    1980-01-01

    This paper reviews the basic theoretical description of the solubility and diffusion of rare gas atoms in crystalline solids. It then shows how this description can be used in conjunction with atomistic calculations to understand experimental observations. This understanding is particularly good for ionic compounds and a brief summary of the present situation is given for three main classes, namely those with the rocksalt structure, the fluorite structure and the caesium chloride structure. (author)

  1. D2O clusters isolated in rare-gas solids: Dependence of infrared spectrum on concentration, deposition rate, heating temperature, and matrix material

    Science.gov (United States)

    Shimazaki, Yoichi; Arakawa, Ichiro; Yamakawa, Koichiro

    2018-04-01

    The infrared absorption spectra of D2O monomers and clusters isolated in rare-gas matrices were systematically reinvestigated under the control of the following factors: the D2O concentration, deposition rate, heating temperature, and rare-gas species. We clearly show that the cluster-size distribution is dependent on not only the D2O concentration but also the deposition rate of a sample; as the rate got higher, smaller clusters were preferentially formed. Under the heating procedures at different temperatures, the cluster-size growth was successfully observed. Since the monomer diffusion was not enough to balance the changes in the column densities of the clusters, the dimer diffusion was likely to contribute the cluster growth. The frequencies of the bonded-OD stretches of (D2O)k with k = 2-6 were almost linearly correlated with the square root of the critical temperature of the matrix material. Additional absorption peaks of (D2O)2 and (D2O)3 in a Xe matrix were assigned to the species trapped in tight accommodation sites.

  2. Radioactive rare gas recoverying device

    International Nuclear Information System (INIS)

    Kasai, Shigeo

    1989-01-01

    The apparatus of the present invention comprises a vessel for containing coolants, an introduction valve and an introduction pipe for introducing radioactive rare gases and an adsorption floor disposed in the coolants. A josephson device is disposed being immersed in the coolants between a radiation detector for detecting the radioactive level adsorbed to the adsorption floor and a driving section for driving the introduction valve by the signal from the detector. With this constitution, radioactive rare gases introduced into the coolants and then cooled and liquefied are recovered by the adsorption floor. As the adsorption proceeds and when the radioactivity level exceeds a maximum level in the effective shielding range of the recovery apparatus, the signal current from the radiation detector also exceeds a predetermined level. If radioactivity exceeds the maximum level, the electrical resistance of the josephson device is increased infinitely by the josephson effect to close the introduction valve. Accordingly, the radioactivity is not absorbed beyond the effective shielding range. (I.S.)

  3. Development of fast-release solid catchers for rare isotopes

    Science.gov (United States)

    Nolen, Jerry; Greene, John; Elam, Jeffrey; Mane, Anil; Sampathkumaran, Uma; Winter, Raymond; Hess, David; Mushfiq, Mohammad; Stracener, Daniel; Wiendenhoever, Ingo

    2015-04-01

    Porous solid catchers of rare isotopes are being developed for use at high power heavy ion accelerator facilities such as RIKEN, FRIB, and RISP. Compact solid catchers are complementary to helium gas catchers for parasitic harvesting of rare isotopes in the in-flight separators. They are useful for short lived isotopes for basic nuclear physics research and longer-lived isotopes for off-line applications. Solid catchers can operate effectively with high intensity secondary beams, e.g. >> 1E10 atoms/s with release times as short as 10-100 milliseconds. A new method using a very sensitive and efficient RGA has been commissioned off-line at Argonne and is currently being shipped to Florida State University for in-beam measurements of the release curves using stable beams. The same porous solid catcher technology is also being evaluated for use in targets for the production of medical isotopes such as 211-At. Research supported by the U.S. DOE Office of Nuclear Physics under the SBIR Program and Contract # DE-AC02-06CH11357 and a University of Chicago Comprehensive Cancer Center/ANL Pilot Project.

  4. Gas transport in solid oxide fuel cells

    CERN Document Server

    He, Weidong; Dickerson, James

    2014-01-01

    This book provides a comprehensive overview of contemporary research and emerging measurement technologies associated with gas transport in solid oxide fuel cells. Within these pages, an introduction to the concept of gas diffusion in solid oxide fuel cells is presented. This book also discusses the history and underlying fundamental mechanisms of gas diffusion in solid oxide fuel cells, general theoretical mathematical models for gas diffusion, and traditional and advanced techniques for gas diffusivity measurement.

  5. Lattice distortion in hcp rare gas solids

    Science.gov (United States)

    Grechnev, A.; Tretyak, S. M.; Freiman, Yu. A.

    2010-04-01

    The lattice distortion parameter δ ≡c/a-√8/3 has been calculated as a function of molar volume for the hcp phases of He, Ar, Kr, and Xe. Results from both semi-empirical potentials and density functional theory are presented. Our study shows that δ is negative for helium in the entire pressure range. For Ar, Kr, and Xe δ changes sign from negative to positive as the pressure increases, growing rapidly in magnitude at higher pressures.

  6. Interaction of rare gas metastable atoms

    International Nuclear Information System (INIS)

    Wang, A.Z.F.

    1977-11-01

    The physical and chemical properties of metastable rare gas atoms are discussed and summarized. This is followed by a detailed examination of the various possible pathways whereby the metastable's excess electronic energy can be dissipated. The phenomenon of chemi-ionization is given special emphasis, and a theoretical treatment based on the use of complex (optical) potential is presented. This is followed by a discussion on the unique advantages offered by elastic differential cross section measurements in the apprehension of the fundamental forces governing the ionization process. The methodology generally adopted to extract information about the interaction potential for scattering data is also systematically outlined. Two widely studied chemi-ionization systems are then closely examined in the light of accurate differential cross section measurements obtained in this work. The first system is He(2 3 S) + Ar for which one can obtain an interaction potential which is in good harmony with the experimental results of other investigators. The validity of using the first-order semiclassical approximation for the phase shifts calculation in the presence of significant opacities is also discussed. The second reaction studied is He*+D 2 for which measurements were made on both spin states of the metastable helium. A self-consistent interaction potential is obtained for the triplet system, and reasons are given for not being able to do likewise for the singlet system. The anomalous hump proposed by a number of laboratories is analyzed. Total elastic and ionization cross sections as well as rate constants are calculated for the triplet case. Good agreement with experimental data is found. Finally, the construction and operation of a high power repetitively pulsed nitrogen laser pumped dye laser system is described in great details. Details for the construction and operation of a flashlamp pumped dye laser are likewise given

  7. In situ TEM observation of solid-gas reactions

    International Nuclear Information System (INIS)

    Kishita, K; Kamino, T; Watabe, A; Kuroda, K; Saka, H

    2008-01-01

    Under a gaseous atmosphere at high temperatures, almost all the materials (metal, catalysts, etc.) change their structures and properties. For the research and development of materials, it is of vital importance to clarify mechanisms of solid-gas and liquid-gas reactions. Recently an in situ TEM system combined with an environmental holder, which has a gas injection nozzle close to a specimen-heating element, has been developed. The gas injection nozzle permits gas to flow around the specimens sitting on the heating element made of a fine W filament. The newly developed in situ TEM has a differential pumping system; therefore, the pressure in the specimen chamber is maintained in the range of higher than 1 Pa, while the pressure in the electron gun chamber can be kept in the range of 10 -5 Pa. This system was applied to in situ observation of chemical reactions of metals with gases: Observation of oxidation and reduction under a gas pressure ranging from 10 -5 Pa to 1 Pa at high temperatures (room temperature to ∼1473 K) were successfully carried out on pure metal and rare metal catalysts at near-atomic resolution. This in situ environmental TEM system is promising for clarifying mechanisms of many solid-gas and liquid-gas reactions that take place at high temperatures under a gas atmosphere.

  8. Capillary gas-solid chromatography

    International Nuclear Information System (INIS)

    Berezkin, V.G.

    1996-01-01

    Modern state of gas adsorption chromatography in open capillary columns has been analyzed. The history of the method development and its role in gas chromatography, ways to construct open adsorptional capillary columns, foundations of the theory of retention and washing of chromatographic regions in gas adsorption capillary columns have been considered. The fields is extensively and for analyzing volatile compounds of different isotopic composition, inorganic and organic gases, volatile organic polar compounds, aqueous solutions of organic compounds. Separation of nuclear-spin isomers and isotopes of hydrogen is the first illustrative example of practical application of the adsorption capillary chromatography. It is shown that duration of protium and deuterium nuclear isomers may be reduced if the column temperature is brought to 47 K

  9. Solid gas reaction phase diagram under high gas pressure

    International Nuclear Information System (INIS)

    Ishizaki, K.

    1992-01-01

    This paper reports that to evaluate which are the stable phases under high gas pressure conditions, a solid-gas reaction phase diagram under high gas pressure (HIP phase diagram) has been proposed by the author. The variables of the diagram are temperature, reactant gas partial pressure and total gas pressure. Up to the present time the diagrams have been constructed using isobaric conditions. In this work, the stable phases for a real HIP process were evaluated assuming an isochoric condition. To understand the effect of the total gas pressure on stability is of primary importance. Two possibilities were considered and evaluated, those are: the total gas pressure acts as an independent variable, or it only affects the fugacity values. The results of this work indicate that the total gas pressure acts as an independent variable, and in turn also affects the fugacity values

  10. PULSE RADIOLYSIS IN SUPERCRITICAL RARE GAS FLUIDS

    International Nuclear Information System (INIS)

    HOLROYD, R.

    2007-01-01

    Recently, supercritical fluids have become quite popular in chemical and semiconductor industries for applications in chemical synthesis, extraction, separation processes, and surface cleaning. These applications are based on: the high dissolving power due to density build-up around solute molecules, and the ability to tune the conditions of a supercritical fluid, such as density and temperature, that are most suitable for a particular reaction. The rare gases also possess these properties and have the added advantage of being supercritical at room temperature. Information about the density buildup around both charged and neutral species can be obtained from fundamental studies of volume changes in the reactions of charged species in supercritical fluids. Volume changes are much larger in supercritical fluids than in ordinary solvents because of their higher compressibility. Hopefully basic studies, such as discussed here, of the behavior of charged species in supercritical gases will provide information useful for the utilization of these solvents in industrial applications

  11. Dynamics of exciplex formation in rare gas media

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Lorenzo, German, E-mail: grojas37@gmail.com [Departamento de Fisica General y Matematicas, Instituto Superior de Tecnologias y Ciencias Aplicadas, La Habana (Cuba)] [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain); Rubayo-Soneira, Jesus [Departamento de Fisica General y Matematicas, Instituto Superior de Tecnologias y Ciencias Aplicadas, La Habana (Cuba); Alberti, Sebastian Fernandez [Centro de Estudios e Investigaciones, Universidad Nacional de Quilmes, Roque Saenz Pena 180, Bernal B1876BXD (Argentina)

    2009-07-30

    A hopping-surface algorithm has been used to simulate the dynamics induced in rare gas matrices due to the photoexcitation ({sup 1}S{sub 0} {yields} {sup 3}P{sub 1}) of atomic mercury embedded in them. Especially, the study of the dynamics of an exciplex formation in a model system consisting of solid xenon doped with atomic mercury. The process starts upon the photoexcitation of the Hg atom to its {sup 3}P{sub 1} electronic excited state. Diatomics-in-Molecule approach has been used for constructing the adiabatic potential surfaces. In all trajectories we show that a triatomic Xe-Hg{sup *}-Xe complex is formed, but in two conformations: bent and linear. The mechanisms leading to the formation of one or the other are identified. Mainly, are noted the thermal fluctuations of the Hg impurity and the shape of the potential surfaces. Furthermore, we show that non-radiative intrastate relaxation occurs via a conical intersection between the excited state surfaces. The simulated spectra are in very good agreement with the experimental data.

  12. Dynamics of exciplex formation in rare gas media

    International Nuclear Information System (INIS)

    Rojas-Lorenzo, German; Rubayo-Soneira, Jesus; Alberti, Sebastian Fernandez

    2009-01-01

    A hopping-surface algorithm has been used to simulate the dynamics induced in rare gas matrices due to the photoexcitation ( 1 S 0 → 3 P 1 ) of atomic mercury embedded in them. Especially, the study of the dynamics of an exciplex formation in a model system consisting of solid xenon doped with atomic mercury. The process starts upon the photoexcitation of the Hg atom to its 3 P 1 electronic excited state. Diatomics-in-Molecule approach has been used for constructing the adiabatic potential surfaces. In all trajectories we show that a triatomic Xe-Hg * -Xe complex is formed, but in two conformations: bent and linear. The mechanisms leading to the formation of one or the other are identified. Mainly, are noted the thermal fluctuations of the Hg impurity and the shape of the potential surfaces. Furthermore, we show that non-radiative intrastate relaxation occurs via a conical intersection between the excited state surfaces. The simulated spectra are in very good agreement with the experimental data.

  13. Recurrence of Solid Pseudopapillary Tumor: A Rare Pancreatic Tumor

    Directory of Open Access Journals (Sweden)

    Chandra Punch

    2016-01-01

    Full Text Available Solid pseudopapillary tumor of the pancreas (SPTP is a rare disease of young females that does not usually recur after resection. Here we report a case of an elderly female with history of SPTP ten years ago who presented with anorexia and a palpable left lower quadrant abdominal mass. Imaging revealed metastatic disease and US-guided biopsy of the liver confirmed the diagnosis of SPTP. Due to her advanced age and comorbidities, she elected to undergo hospice care. The objective of this case report is to increase awareness of this tumor and its possibility of recurrence, necessitating further guidelines for follow-up.

  14. Thermodynamics of gas adsorption on solid adsorbents

    International Nuclear Information System (INIS)

    Budrugeac, P.

    1979-01-01

    Starting with several hypotheses about the adsorbtion system and the adsorption phenomenon, a thermodynamic treatment of gas adsorption on solid adsorbants is presented. The relationships for determination from isotherms and calorimetric data of thermodynamic functions are derived. The problem of the phase changes in adsorbed layer is discussed. (author)

  15. Soft landing of size selected clusters in rare gas matrices

    International Nuclear Information System (INIS)

    Lau, J.T; Wurth, W.; Ehrke, H-U.; Achleitner, A.

    2003-01-01

    Soft landing of mass selected clusters in rare gas matrices is a technique used to preserve mass selection in cluster deposition. To prevent fragmentation upon deposition, the substrate is covered with rare gas matrices to dissipate the cluster kinetic energy upon impact. Theoretical and experimental studies demonstrate the power of this technique. Besides STM, optical absorption, excitation, and fluorescence experiments, x-ray absorption at core levels can be used as a tool to study soft landing conditions, as will be shown here. X-ray absorption spectroscopy is also well suited to follow diffusion and agglomeration of clusters on surfaces via energy shifts in core level absorption

  16. Solid state gas sensors. Industrial application

    Energy Technology Data Exchange (ETDEWEB)

    Fleischer, Maximilian [Siemens AG, Muenchen (Germany). Corporate Technology; Lehmann, Mirko (eds.) [Innovative Sensor Technology (IST) AG, Wattwil (Switzerland)

    2012-11-01

    Written by experts. Richly illustrated. Encourages future research and investments in the fascinating field of gas sensors. Gas sensor products are very often the key to innovations in the fields of comfort, security, health, environment, and energy savings. This compendium focuses on what the research community labels as solid state gas sensors, where a gas directly changes the electrical properties of a solid, serving as the primary signal for the transducer. It starts with a visionary approach to how life in future buildings can benefit from the power of gas sensors. The requirements for various applications, such as for example the automotive industry, are then discussed in several chapters. Further contributions highlight current trends in new sensing principles, such as the use of nanomaterials and how to use new sensing principles for innovative applications in e.g. meteorology. So as to bring together the views of all the different groups needed to produce new gas sensing applications, renowned industrial and academic representatives report on their experiences and expectations in research, applications and industrialisation.

  17. Infra-red absorption in rare-gas mixtures

    International Nuclear Information System (INIS)

    Weiss, S.

    1980-01-01

    Infrared absorption in rare-gas mixtures has been studied extensively, so that by now the spectra at room temperature of almost all pairs are available. Turning attention first to the gas phase, it is shown that the considerable mass of experimental results can be reduced to yield a relatively simple picture. Having reviewed the experimental facts, the interpretation and extraction of information is discussed. (KBE)

  18. Behaviour of rare gases in solids at high temperature; Comportement des gaz rares dans les solides a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Blin, J [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    In this article a number of simple results regarding the solubility and displacement of rare gases in solids have been assembled. These results were obtained from elementary considerations on highly compressed gases and on dislocations. They provide a better understanding of the now fairly numerous experiments dealing with the swelling of irradiated fuels, this swelling being due to the presence of a high proportion of gases in the fission products. Finally, the chances of success of the various methods which may be devised to diminish the swelling are examined. (author) [French] Nous avons rassemble dans ce texte un certain nombre de resultats simples relatifs a la solubilite et au deplacement des gaz rares dans les solides. Ces resultats ont ete obtenus par des considerations elementaires sur les gaz tres comprimes et sur les dislocations. Ils permettent de mieux comprendre les experiences, maintenant assez nombreuses, qui ont trait au gonflement des combustibles irradies; gonflement qui est du a la presence d'une forte proportion de gaz dans les produits de fission. On examine finalement les chances de succes des differents moyens que l'on peut imaginer pour attenuer le gonflement. (auteur)

  19. Method for improved gas-solids separation

    Science.gov (United States)

    Kusik, C.L.; He, B.X.

    1990-11-13

    Methods are disclosed for the removal of particulate solids from a gas stream at high separation efficiency, including the removal of submicron size particles. The apparatus includes a cyclone separator type of device which contains an axially mounted perforated cylindrical hollow rotor. The rotor is rotated at high velocity in the same direction as the flow of an input particle-laden gas stream to thereby cause enhanced separation of particulate matter from the gas stream in the cylindrical annular space between the rotor and the sidewall of the cyclone vessel. Substantially particle-free gas passes through the perforated surface of the spinning rotor and into the hollow rotor, from where it is discharged out of the top of the apparatus. Separated particulates are removed from the bottom of the vessel. 4 figs.

  20. Solid Organic Deposition During Gas Injection Studies

    DEFF Research Database (Denmark)

    Dandekar, Abhijit Y.; Andersen, Simon Ivar; Stenby, Erling Halfdan

    2000-01-01

    Recently a series of first contact miscibility (swelling) experiments have been performed on undersaturated light and heavy oils using LPG rich and methane rich injection gases, in which solid organic deposition was observed. A compositional gradient in the oils during the gas injection process....... The asphaltene content of the different oil samples were determined by the TP 143 method. The standard asphaltenes and the solid organic deposit recovered from the swelling tests were analyzed using FTIR, HPLC-SEC and H-1 NMR. The aim of these analyses is to reveal the molecular nature of the deposits formed...... during the gas injection process in comparison with the standard asphaltenes in order to understand the mechanisms involved in asphaltene deposition....

  1. Method of storing radioactive rare gas. [gas occupies spaces in the zeolite crystal lattice

    Energy Technology Data Exchange (ETDEWEB)

    Nagao, H; Miharada, H; Takiguchi, Y; Kanazawa, T; Soya, M

    1975-05-15

    A method is provided to prevent dispersion of radioactive rare gas atoms by sealing them in a pressurised state within zeolite and thereby confining them in position within the zeolite crystal lattice. Radioactive rare gas is separated from exhaust gas and concentrated by using a low temperature adsorption means or liquefaction distillation means and necessary accessory means, and then it is temporarily stored in a gas holder. When a predetermined quantity of storage is reached, the gas is led to a sealing tank containing zeolite heated to 300 to 400/sup 0/C and held at 3,000 to 4,000 atmospheres, and under this condition radioactive rare gas is brought to occupy the spaces in the zeolite crystal lattice. After equilibrium pressure is reached by the pressure in the tank at that temperature, the gas is cooled in the pressurised state down to room temperature. Subsequently, the rare gas remaining in the tank and duct is recovered by a withdrawal pump into the gas holder. Thereafter, the zeolite with radioactive rare gas sealed in it is taken out from the tank and sealed within a long period storage container, which is then housed in a predetermined place for storage.

  2. A Model of Solid State Gas Sensors

    Science.gov (United States)

    Woestman, J. T.; Brailsford, A. D.; Shane, M.; Logothetis, E. M.

    1997-03-01

    Solid state gas sensors are widely used to measure the concentrations of gases such as CO, CH_4, C_3H_6, H_2, C_3H8 and O2 The applications of these sensors range from air-to-fuel ratio control in combustion processes including those in automotive engines and industrial furnaces to leakage detection of inflammable and toxic gases in domestic and industrial environments. As the need increases to accurately measure smaller and smaller concentrations, problems such as poor selectivity, stability and response time limit the use of these sensors. In an effort to overcome some of these limitations, a theoretical model of the transient behavior of solid state gas sensors has been developed. In this presentation, a model for the transient response of an electrochemical gas sensor to gas mixtures containing O2 and one reducing species, such as CO, is discussed. This model accounts for the transport of the reactive species to the sampling electrode, the catalyzed oxidation/reduction reaction of these species and the generation of the resulting electrical signal. The model will be shown to reproduce the results of published steady state models and to agree with experimental steady state and transient data.

  3. The present status of rare gas release control

    International Nuclear Information System (INIS)

    Yamamoto, Hiroshi

    1974-01-01

    Of the rare gases Ar, Kr and Xe released from nuclear facilities, the problem of release control can be confined to 41 Ar, 85 Kr and 133 Xe. The cases of the latter two are described, as 41 Ar is not much significant. 133 Xe, having relatively short half-life, can be dealt sufficiently by holding-up in case of light water reactors. 85 Kr of long half-life must be removed : the methods are low temperature adsorption, liquefaction distillation, absorption and diaphragm method. As for future problem, there is disposal of concentrated rare gas. (Mori, K.)

  4. Calculated apparent yields of rare gas fission products

    International Nuclear Information System (INIS)

    Delucchi, A.A.

    1975-01-01

    The apparent fission yield of the rare gas fission products from four mass chains is calculated as a function of separation time for six different fissioning systems. A plot of the calculated fission yield along with a one standard deviation error band is given for each rare gas fission product and for each fissioning system. Those parameters in the calculation that were major contributors to the calculated standard deviation at each separation time were identified and the results presented on a separate plot. To extend the usefulness of these calculations as new and better values for the input parameters become available, a third plot was generated for each system which shows how sensitive the derived fission yield is to a change in any given parameter used in the calculation. (U.S.)

  5. Gas Generation from Solids in Aqueous Suspensions

    International Nuclear Information System (INIS)

    Meisel, D.; Schatz, T.

    1999-01-01

    The presence of solid particles suspended in solution may change the radiation-induced chemistry of a system in many ways. Catalytic surface effects may manifest themselves through the acceleration or inhibition of various reactions. As importantly, the yield of primary radiolysis products may be affected as the solids absorb a significant fraction of the radiation energy. The latter is the subject of this study. We explore the possibility that absorption of radiation by the solid particles may initiate chemistry in the water. This is a question of fundamental as well as practical significance. On the fundamental side we ask whether electron-hole pairs generated in the solid phase can escape and cross into the aqueous phase and initiate chemical reactions such as gas generation and how this possibility depends on the energy levels of the material and on particle size. From a practical angle, such questions are directly relevant to any heterogeneous system exposed to radiation. High-level waste temporarily stored in underground tanks, low-level waste permanently stored in humid grout, or soil particles migrating in geological formations are but a few examples

  6. The injection of inert gas ions into solids: their trapping and escape

    International Nuclear Information System (INIS)

    Carter, G.; Armour, D.G.; Donnelly, S.E.; Ingram, D.C.; Webb, R.P.

    1980-01-01

    Basic information is required to understand fission gas generation and its consequence for swelling and embrittlement in fission reactors, for understanding and controlling first wall problems in fusion reactors and for attempting to design storage for active gas waste. In all of these areas the rare gas atoms are generated with kinetic energy and may thus interact differently, during their slowing down, with the solid than if they had been introduced more gently (e.g. via diffusion) into the solid. An important method of simulating the behaviour of such energetic rare gas atoms in solids is via external irradiation of the solid with rare gas ions of appropriate species and energies and it is the purpose of this review to evaluate studies of this nature. The review is divided into three parts. The first describes experimental techniques, discusses the results of measurements of how ions penetrate into and may be retained in a solid, and outlines theoretical interpretations of the data. The mechanisms of gas atom dissolution and thermal transport in solids are of profound importance and so, in the second part of this review, attention is devoted to how the technique of post-implantation thermal evolution spectrometry can be employed to attempt to understand some of these processes. Particular attention is paid to the difficulties of unique interpretation of evolution spectra. In the final section, consideration will be given to the processes which lead to the inevitable saturation of solids undergoing continued irradiation with rare gas ions and experimental measurements and their probable interpretation will be discussed. Since many materials are of importance in the context of this symposium, reference will be made to as broad a range of studies as possible. (author)

  7. Study on the excited diatomic molecules of rare gas

    International Nuclear Information System (INIS)

    Kasama, Kunihiko; Arai, Shigeyoshi

    1981-01-01

    The study on the excited diatomic molecules of rare gas is presented. The absorption spectra, the mechanism of formation and attenuation and the reactions with other molecules are described. The excitation of rare gas was made by using a pulsed electron beam generator. The absorption of excited diatomic molecules was measured as the functions of time. Two absorption peaks were observed. The electron states of rare gases were estimated. The observed and calculated transition values were given for each peak. The absorption spectra of Ne change with time. The spectra of Ar do not change with time. Four and eleven absorption maxima were seen in the spectra of Kr and Xe, respectively. In the case of Ar, the thermal equilibrium existed. The constants of the production and attenuation rates were obtained as the functions of Ar gas pressure. In the case of Ne, there wad definitely the time dependence of absorption spectra. The attenuation constant was obtained for each transition between various vibration levels. It is necessary to consider the relaxation from high vibrational levels. The energy transfer between vibrational levels hardly occurred in Ne because the intervals are large. When there are other molecules, the attnuation was accelerated. (Kato, T.)

  8. Saturation characteristics of liquid rare gas ionization chambers and recombination luminescence in liquid rare gas scintillation

    International Nuclear Information System (INIS)

    Takahashi, Tan; Konno, Satoshi; Kubota, Shinzo; Nakamoto, Jun; Miyajima, Mitsuhiro.

    1978-01-01

    From the saturation characteristics of liquid rare gases (Ar and Xe), the mean distance between electrons and ions. W-value, and the ratio of freely diffusion electrons were determined on the basis of the theory of Onsager. Their relationships with the scintillation due to recombination are also discussed. In the first part of this report, an analytic equation for the probability that an electron escapes from preferential recombination under the existence of an electric field is derived. The equation was then numerically solved with a computer code developed by Freeman. The adjusted parameters and the results of calculations for both Xe and Ar are presented together with the experimental results. Some discrepancy appeared between the analytical and the experimental results when the electric field was weak, and it is ascribable to the existence of the columnar (cluster) recombination and the effect of attachment due to the pulse method employed in the experiments. In the second part, the effect of electric field on the scintillation of liquid rare gases is considered, based on the theory of Onsager. (Aoki, K.)

  9. Taylor flow hydrodynamics in gas-liquid-solid micro reactors

    NARCIS (Netherlands)

    Warnier, M.J.F.

    2009-01-01

    Chemical reactions in which a gas phase component reacts with a liquid phase omponent at the surface of a solid catalyst are often encountered in chemical industry. The rate of such a gas-liquid-solid reaction is often limited by the mass transfer rate of the gas phase component, which depends on

  10. Cross section determination for the higher ionization of rare gas ions by electron collisions

    International Nuclear Information System (INIS)

    Becker, R.; Frodl, R.; Klein, H.; Schmidt, W.; Clausnitzer, G.; Klinger, H.; Mueller, A.; Salzborn, E.; Fuchs, G.; Viehboeck, F.

    1975-01-01

    The higher ionization of rare gas ions is reported on, which were excited by an electron beam using a crossed-beam technique. A detector for the identification of metastable excited rare gas ions was developed. (WL) [de

  11. VUV spectroscopy of rare gas van der Waals dimers

    International Nuclear Information System (INIS)

    Dehmer, P.M.; Pratt, S.T.

    1982-01-01

    We have undertaken a systematic study of the photoionization spectra of the homonuclear and heteronuclear rare gas dimers in order to better understand the nature of the bonding in the Rydberg states adnd ions of these molecules. We have obtained results for Ar 2 , Kr 2 , Xe 2 , NeAr, NeKr, NeXe, ArKr, ArXe, and KrXe. Of the remaining dimer species (Ne 2 and the Herare gas dimers), only Ne 2 has been studied using photoionization mass spectrometry. The results of the present series of experiments provide information both on the excited states of the neutral dimers and on the ground and excited states of the dimer ions. Using the data obtained in these measurements, we are able to compile for the first time a nearly complete list of ground state dissociation energies for the homonuclear and heteronuclear rare gas dimer ions. Somewhat less complete results are obtained for the excited states of these species. The observed trends in binding energy provide an excellent example of the systematic changes that occur as a result of changes in atomic orbital energies, polarizability, and internuclear distance, and these trends can be explained qualitatively in terms of simple molecular orbital theory

  12. Accurate Ne-heavier rare gas interatomic potentials

    International Nuclear Information System (INIS)

    Candori, R.; Pirani, F.; Vecchiocattivi, F.

    1983-01-01

    Accurate interatomic potential curves for Ne-heavier rare gas systems are obtained by a multiproperty analysis. The curves are given via a parametric function which consists of a modified Dunham expansion connected at long range with the van der Waals expansion. The experimental properties considered in the analysis are the differential scattering cross sections at two different collision energies, the integral cross sections in the glory energy range and the second virial coefficients. The transport properties are considered indirectly by using the potential energy values recently obtained by inversion of the transport coefficients. (author)

  13. Device for separating and concentrating rare gases containing krypton gas

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, S; Sugimoto, K

    1975-06-11

    In orer to highly concentrate krypton by means of adsorption and desorption of activated carbon, in a device for continuously separating and concentrating rare gases containing krypton gas by means of adsorbing and desorbing operation of activated carbon, the device includes adsorbers arranged in parallel and more than two stages of adsorbers arranged in series with the first mentioned adsorbers with the amount of activated carbon filled successively reduced, and a cooling mechanism for cooling the adsorbers when adsorbed and a heating mechanism for heating the adsorbers when desorbed.

  14. Flow regimes in vertical gas-solid contact systems

    Energy Technology Data Exchange (ETDEWEB)

    Yerushalmi, J.; Cankurt, N. T.; Geldart, D.; Liss, B.

    1976-01-01

    The flow characteristics in fluidized beds, i.e., gas-solid systems, was studied to determine the flow regimes, the interaction of gas and solid in the various flow regimes and the dependence of this interaction and of transition between flow regimes on the properties of the gas and solid, on the gas and solid flow rates, and on the containing vessel. Fluidized beds with both coarse and fine particles are considered. Test results using high speed photography to view the operation of a 2-dimensional bed are discussed. (LCL)

  15. Visualizing Gas Adsorption on Porous Solids: Four Simple, Effective Demonstrations

    Science.gov (United States)

    Cheung, Ocean

    2014-01-01

    Gas adsorption on porous solids is a topic that is often discussed in an undergraduate chemistry or chemical engineering course. The idea of porosity and gas adsorption on a porous solid is usually discussed with adsorption isotherms recorded using commercially available equipment. This discussion can be rather abstract and can be difficult for…

  16. High-Intensity Femtosecond Laser Interaction with Rare Gas Clusters

    Institute of Scientific and Technical Information of China (English)

    林亚风; 钟钦; 曾淳; 陈哲

    2001-01-01

    With a 45 fs multiterawatt 790 nm laser system and jets of argon and krypton atomic clusters, a study of the interaction of fs intense laser pulses with large size rare gas dusters was conducted. The maximum laser intensity of about 7 × 1016 W/cm2 and dusters composed of thousands of atoms which were determined through Rayleigh scattering measurements were involved inthe experiments. On the one hand, the results indicate that the interaction is strongly cluster size dependent. The stronger the interaction, the larger the clusters are. On the other hand, a saturation followed by a drop of the energy of ions ejected from the interaction will occur when the laser intensity exceeds a definite value for clusters of a certain size.

  17. Interaction of rare gas clusters in intense laser field

    International Nuclear Information System (INIS)

    Dobosz, Sandrine

    1998-01-01

    Rare gas cluster jet targets have only been scarcely studied in strong laser fields. This is surprising since their properties are particularly appealing. Although considered as a gas phase target, the local density within clusters is comparable to that of the bulk. Intense irradiation of clusters produces a plasma thereby giving rise to strong collisional heating. This explains, in particular, the observation of very high fragment charge states and the generation of X-rays in the keV energy range. The complete set of our experimental results shows that the intra-cluster atoms are first ionised by tunnel ionisation followed by massive electron impact ionisation. Thus, for Xenon clusters, we have observed up to 30-fold charged. The most energetic electrons leave the cluster which contributes to a positive charge build-up on the cluster surface. The plasma expands under the combined action of the Coulomb and kinetic pressures. The contribution of each pressure depends on the cluster size and we show that the Coulomb pressure is prevailing for the smallest sizes. This scenario explains the ejection of fragments with energies of up to lMeV. We have also performed a high resolution X-ray study to explore in situ the properties of the plasma. These studies underline the importance of electron-ion collisions and allow to deterrnine the mean charge states of the emitting ions. Finally, we have developed a model, describing the cluster expansion, which confirms our experimental observations. (author) [fr

  18. Penning ionization cross sections of excited rare gas atoms

    International Nuclear Information System (INIS)

    Ukai, Masatoshi; Hatano, Yoshihiko.

    1988-01-01

    Electronic energy transfer processes involving excited rare gas atoms play one of the most important roles in ionized gas phenomena. Penning ionization is one of the well known electronic energy transfer processes and has been studied extensively both experimentally and theoretically. The present paper reports the deexcitation (Penning ionization) cross sections of metastable state helium He(2 3 S) and radiative He(2 1 P) atoms in collision with atoms and molecules, which have recently been obtained by the authors' group by using a pulse radiolysis method. Investigation is made of the selected deexcitation cross sections of He(2 3 S) by atoms and molecules in the thermal collisional energy region. Results indicate that the cross sections are strongly dependent on the target molecule. The deexcitation probability of He(2 3 S) per collision increases with the excess electronic energy of He(2 3 S) above the ionization potential of the target atom or molecule. Another investigation, made on the deexcitation of He(2 1 P), suggests that the deexcitation cross section for He(2 1 P) by Ar is determined mainly by the Penning ionization cross section due to a dipole-dipole interaction. Penning ionization due to the dipole-dipole interaction is also important for deexcitation of He(2 1 P) by the target molecules examined. (N.K.)

  19. Rare-gas dependence of the self-quenching streamer

    International Nuclear Information System (INIS)

    Yoshioka, K.; Hashimoto, M.; Koori, N.; Kumabe, I.; Ohgaki, H.; Matoba, M.

    1989-01-01

    The self-quenching streamer (SQS) mode is understood these days as one of the basic modes of gas counter operation. In the present work, the SQS transition is clearly observed for Ar-, Kr- and Xe-mixtures with CH 4 , C 2 H 6 , C 3 H 8 , isoC 4 H 10 and CO 2 , and for He- and Ne-mixtures with C 2 H 6 , C 3 H 8 and isoC 4 H 10 . For He- and Ne-mixtures with CH 4 or CO 2 , the GM discharge is developed instead of the SQS transition. The avalanche size at the transition voltage decreases, in the order of He-, Ne-, Ar-, Kr- and Xe-mixtures, except for He-mixtures with CH 4 or CO 2 . The mechanisms of the SQS transition proposed by Atac et al. and Zhang have disadvantages in explaining all these results. If the photo-ionization is assumed as in Atac's mechanism, energetic photons whose yield is sufficiently large are needed for the SQS transition. The interaction between metastable states of rare gases proposed by Zhang may be energetically capable of producing electrons for the transition; effects of quenching gas in mixtures cannot be explained by this mechanism. Further investigation is necessary for microscopic processes occurring in the avalanche development. More detailed information is required on the atomic reaction cross sections of photo-ionization, radiative recombination, etc. (N.K.)

  20. Solid pseudopapillary tumor of pancreas with sickle cell trait: A rare case report

    Directory of Open Access Journals (Sweden)

    Harish S Permi

    2013-01-01

    Full Text Available Solid pseudopapillary tumor of pancreas is a rare pancreatic neoplasm affecting young women, has low malignant potential and amenable for surgical excision with good long-term survival. Sickle cell trait is benign condition, which involves one normal beta-globin chain and one HbS chain. Although it is a benign condition, individuals are prone to have rare complications that may predispose to death under certain circumstances. We report a rare coexistence of solid pseudopapillary tumor of pancreas with sickle cell trait in an 18-year-old female who underwent distal pancreatectomy with splenectomy. Histopathological examination and haemoglobin electrophoresis confirmed the diagnosis.

  1. Rapid-relocation model for describing high-fluence retention of rare gases implanted in solids

    Science.gov (United States)

    Wittmaack, K.

    2009-09-01

    It has been known for a long time that the maximum areal density of inert gases that can be retained in solids after ion implantation is significantly lower than expected if sputter erosion were the only limiting factor. The difference can be explained in terms of the idea that the trapped gas atoms migrate towards the surface in a series of detrapping-trapping events so that reemission takes place well before the receding surface has advanced to the original depth of implantation. Here it is shown that the fluence dependent shift and shape of implantation profiles, previously determined by Rutherford backscattering spectrometry (RBS), can be reproduced surprisingly well by extending a simple retention model originally developed to account only for the effect of surface recession by sputtering ('sputter approximation'). The additional migration of inert gas atoms is formally included by introducing an effective shift parameter Yeff as the sum of the sputtering yield Y and a relocation efficiency Ψrel. The approach is discussed in detail for 145 keV Xe + implanted in Si at normal incidence. Yeff was found to increase with increasing fluence, to arrive at a maximum equivalent to about twice the sputtering yield. At the surface one needs to account for Xe depletion and the limited depth resolution of RBS. The (high-fluence) effect of implanted Xe on the range distributions is discussed on the basis of SRIM calculations for different definitions of the mean target density, including the case of volume expansion (swelling). To identify a 'range shortening' effect, the implanted gas atoms must be excluded from the definition of the depth scale. The impact-energy dependence of the relocation efficiency was derived from measured stationary Xe concentrations. Above some characteristic energy (˜20 keV for Ar, ˜200 keV for Xe), Y exceeds Ψrel. With decreasing energy, however, Ψrel increases rapidly. Below 2-3 keV more than 90% of the reemission of Ar and Xe is estimated

  2. Heat transfer across the interface between nanoscale solids and gas.

    Science.gov (United States)

    Cheng, Chun; Fan, Wen; Cao, Jinbo; Ryu, Sang-Gil; Ji, Jie; Grigoropoulos, Costas P; Wu, Junqiao

    2011-12-27

    When solid materials and devices scale down in size, heat transfer from the active region to the gas environment becomes increasingly significant. We show that the heat transfer coefficient across the solid-gas interface behaves very differently when the size of the solid is reduced to the nanoscale, such as that of a single nanowire. Unlike for macroscopic solids, the coefficient is strongly pressure dependent above ∼10 Torr, and at lower pressures it is much higher than predictions of the kinetic gas theory. The heat transfer coefficient was measured between a single, free-standing VO(2) nanowire and surrounding air using laser thermography, where the temperature distribution along the VO(2) nanowire was determined by imaging its domain structure of metal-insulator phase transition. The one-dimensional domain structure along the nanowire results from the balance between heat generation by the focused laser and heat dissipation to the substrate as well as to the surrounding gas, and thus serves as a nanoscale power-meter and thermometer. We quantified the heat loss rate across the nanowire-air interface, and found that it dominates over all other heat dissipation channels for small-diameter nanowires near ambient pressure. As the heat transfer across the solid-gas interface is nearly independent of the chemical identity of the solid, the results reveal a general scaling relationship for gaseous heat dissipation from nanostructures of all solid materials, which is applicable to nanoscale electronic and thermal devices exposed to gaseous environments.

  3. Mass transfer between gas and particles in a gas-solid trickle flow reactor

    NARCIS (Netherlands)

    Kiel, J.H.A.; Kiel, J.H.A.; Prins, W.; van Swaaij, Willibrordus Petrus Maria

    1992-01-01

    Gas-solids mass transfer was studied for counter-current flow of gas and millimetre-sized solid particles over an inert packing at dilute phase or trickle flow conditions. Experimental data were obtained from the adsorption of water vapour on 640 and 2200 ¿m diameter molecular sieve spheres at

  4. Immobilization of Radioactive Rare Earth oxide Waste by Solid Phase Sintering

    International Nuclear Information System (INIS)

    Ahn, Byung Gil; Park, Hwan Seo; Kim, Hwan Young; Lee, Han Soo; Kim, In Tae

    2010-01-01

    In the pyroprocessing of spent nuclear fuels, LiCl-KCl waste salt containing radioactive rare earth chlorides are generated. The radioactive rare earth oxides are recovered by co-oxidative precipitation of rare earth elements. The powder phase of rare earth oxide waste must be immobilized to produce a monolithic wasteform suitable for storage and ultimate disposal. The immobilization of these waste developed in this study involves a solid state sintering of the waste with host borosilicate glass and zinc titanate based ceramic matrix (ZIT). And the rare-earth monazite which synthesised by reaction of ammonium di-hydrogen phosphate with the rare earth oxides waste, were immobilized with the borosilicate glass. It is shown that the developed ZIT ceramic wasteform is highly resistant the leaching process, high density and thermal conductivity.

  5. Cyclodextrin-Based Solid-Gas Clathrates

    NARCIS (Netherlands)

    Pereva, Stiliana; Himitliiska, Tsveta; Spassov, Tony; Stoyanov, S.D.; Arnaudov, L.N.; Dudev, Todor

    2015-01-01

    "Cyclodextrin-gas" clathrates were obtained by crystallization from water solution of α-, β-, and γ-cyclodextrins (CDs) under pressure of the gas to be entrapped into the CD molecules. When the pressure is released, these clathrates are stable at ambient conditions and dissociate at elevated

  6. Dissymmetry effects on the laser spectroscopy of supersonically expanded rare gas/chiral arene heteroclusters.

    Science.gov (United States)

    Filippi, Antonello; Giardini, Anna; Marcantoni, Enrico; Paladini, Alessandra; Piccirillo, Susanna; Renzi, Gabriele; Rondino, Flaminia; Roselli, Graziella; Satta, Mauro; Speranza, Maurizio

    2007-04-14

    The R2PI-TOF spectra of supersonically expanded rare gas/chiral arene heteroclusters have been rationalized in terms of the distortion of the pi-electron density reflecting the different dipole and quadrupole momenta induced in the rare gas atoms by interaction with the opposite pi-faces of the chiral arene itself.

  7. Critical comparison of hydrodynamic models for gas-solid fluidized beds - Part II: freely bubbling gas-solid fluidized beds

    NARCIS (Netherlands)

    Patil, D.J.; van Sint Annaland, M.; Kuipers, J.A.M.

    2005-01-01

    Correct prediction of spontaneous bubble formation in freely bubbling gas¿solid fluidized beds using Eulerian models, strongly depends on the description of the internal momentum transfer in the particulate phase. In this part, the comparison of the simple classical model, describing the solid phase

  8. Gas capture and rare gas retention by accreting planets in the solar nebula

    International Nuclear Information System (INIS)

    Mizuno, H.; Nakazawa, K.; Hayashi, C.

    1982-01-01

    In this paper, the physico-chemical effects of the nebula gas on the planets are reviewed from a standpoint of planetary formation in the solar nebula. The proto-Earth growing in the nebula was surrounded by a primordial atmosphere with a solar chemical composition and solar isotopic composition. When the mass of the proto-Earth was greater than 0.3 times the present Earth mass, the surface was molten because of the blanketing effect of the atmosphere. Therefore, the primordial rare gases contained in the primordial atmosphere dissolved into the molten Earth material without fractionation and in particular the dissolved neon is expected to be conserved in the present Earth material. Hence, if dissolved neon with a solar isotopic ratio is discovered in the Earth material, it will indicate that the Earth was formed in the nebula and that the dissolved rare gases were one of the sources which degassed to form the present atmosphere. (author)

  9. Long-range dispersion interactions. II. Alkali-metal and rare-gas atoms

    International Nuclear Information System (INIS)

    Mitroy, J.; Zhang, J.-Y.

    2007-01-01

    The dispersion coefficients for the van der Waals interactions between the rare gases Ne, Ar, Kr, and Xe and the low-lying states of Li, Na, K, and Rb are estimated using a combination of ab initio and semiempirical methods. The rare-gas oscillator strength distributions for the quadrupole and octupole transitions were derived by using high-quality calculations of rare-gas polarizabilities and dispersion coefficients to tune Hartree-Fock single-particle energies and expectation values

  10. Selected Topics on Mass Transport in Gas-solid Interactions

    DEFF Research Database (Denmark)

    Somers, Marcel A.J.

    2004-01-01

    The present article is a short review containing examples of the role of mass transport in the solid state during gas-solid interactions. Examples are taken from the authors' research on the interaction of carbon and/or nitrogen with iron-based metals. Topics dealt with are diffusion-controlled d......The present article is a short review containing examples of the role of mass transport in the solid state during gas-solid interactions. Examples are taken from the authors' research on the interaction of carbon and/or nitrogen with iron-based metals. Topics dealt with are diffusion...... on the kinetics of phenomena in the solid state. Various experimental techniques were applied to investigate these phenomena; it is however beyond the scope of the present article to treat experimental conditions in detail. The interested reader is referred to the original work for in depth discussions...

  11. Solid state chemistry of rare earth oxides. Final report, September 1, 1950--July 31, 1977

    International Nuclear Information System (INIS)

    Eyring, L.

    1977-07-01

    Work under Contract E(11-1)-1109 and its antecedents has been primarily for the purpose of obtaining detailed thermodynamic, kinetic and structural information on the complex rare earth oxides of praseodymium and terbium. These systems exhibit homologous series of ordered phases, order-disorder transformations, wide-range nonstoichiometric phases, chemical hysteresis in two-phase regions and many other solid state reaction phenomena. Fluorite-related materials of importance to ERDA occur as nuclear fuels, radiation power sources, insulators and solid electrolytes. The rare earth oxides serve directly as model systems for such similar materials and, in a more general sense, they serve as models of solids in general since they exhibit nearly the full range of solid state properties

  12. Physicochemical characterization of some solid materials by inverse gas chromatography

    International Nuclear Information System (INIS)

    Hamieh, T.; Abdessater, S.

    2004-01-01

    Full text.New equations and models on two-dimensional state of solid surfaces were previously elaborated in many other studies. results obtained were used in this paper to the determination and the quantification of some physicochemical properties of some solid surfaces, and especially, to study the acid-base superficial characteristics of some solid substrates like oxides and/or polymer adsorbed on oxides, carbon fibers, cements, etc. The technique used was the inverse gas chromatography (CGI) at infinite dilution. The acid-base constants were calculated for many solid surfaces: Al 2 O 3 , SiO 2 , MgO, ZnO, some cements, textiles and carbon fibers

  13. Methanol synthesis in a countercurrent gas-solid-solid trickle flow reactor. An experimental study

    NARCIS (Netherlands)

    Kuczynski, M.; Oyevaar, M.H.; Pieters, R.T.; Westerterp, K.R.

    1987-01-01

    The synthesis of methanol from CO and H2 was executed in a gas-solid-solid trickle flow reactor. The reactor consisted of three tubular reactor sections with cooling sections in between. The catalyst was Cu on alumina, the adsorbent was a silica-alumina powder and the experimental range 498–523 K,

  14. Analytical study of solids-gas two phase flow

    International Nuclear Information System (INIS)

    Hosaka, Minoru

    1977-01-01

    Fundamental studies were made on the hydrodynamics of solids-gas two-phase suspension flow, in which very small solid particles are mixed in a gas flow to enhance the heat transfer characteristics of gas cooled high temperature reactors. Especially, the pressure drop due to friction and the density distribution of solid particles are theoretically analyzed. The friction pressure drop of two-phase flow was analyzed based on the analytical result of the single-phase friction pressure drop. The calculated values of solid/gas friction factor as a function of solid/gas mass loading are compared with experimental results. Comparisons are made for Various combinations of Reynolds number and particle size. As for the particle density distribution, some factors affecting the non-uniformity of distribution were considered. The minimum of energy dispersion was obtained with the variational principle. The suspension density of particles was obtained as a function of relative distance from wall and was compared with experimental results. It is concluded that the distribution is much affected by the particle size and that the smaller particles are apt to gather near the wall. (Aoki, K.)

  15. Defect structure of cubic solid solutions of alkaline earth and rare earth fluorides

    NARCIS (Netherlands)

    DenHartog, HW

    1996-01-01

    In this paper we will consider the disorder in some cubic solid solutions consisting of one of the alkaline earth fluorides and one of the rare earth fluorides. This is an attractive group of model materials, because these materials have a rather simple overall cubic structure. We will discuss the

  16. Element composition of solid airborne particles deposited in snow in the vicinity of gas-fired heating plant

    OpenAIRE

    Talovskaya, Anna Valerievna; Yazikov, Yegor (Egor) Grigoryevich; Filimonenko, Ekaterina Anatolievna; Samokhina, Nataljya Pavlovna; Shakhova, Tatiana Sergeevna; Parygina, Irina Alekseevna

    2016-01-01

    Local heating plants are the main pollution source of rural areas. Currently, there are few studies on the composition of local heating plants emissions. The article deals with the research results of air pollution level with solid airborne particles in the vicinity of local gas-fired heating plants of some districts of Tomsk region. The snow sampling was conducted for the purpose of solid airborne particles extraction from snow cover. The content of 28 chemical elements (heavy metals, rare e...

  17. An integration scheme for stiff solid-gas reactor models

    Directory of Open Access Journals (Sweden)

    Bjarne A. Foss

    2001-04-01

    Full Text Available Many dynamic models encounter numerical integration problems because of a large span in the dynamic modes. In this paper we develop a numerical integration scheme for systems that include a gas phase, and solid and liquid phases, such as a gas-solid reactor. The method is based on neglecting fast dynamic modes and exploiting the structure of the algebraic equations. The integration method is suitable for a large class of industrially relevant systems. The methodology has proven remarkably efficient. It has in practice performed excellent and been a key factor for the success of the industrial simulator for electrochemical furnaces for ferro-alloy production.

  18. Zirconia-based solid state chemical gas sensors

    CERN Document Server

    Zhuiykov, S

    2000-01-01

    This paper presents an overview of chemical gas sensors, based on solid state technology, that are sensitive to environmental gases, such as O sub 2 , SO sub x , NO sub x , CO sub 2 and hydrocarbons. The paper is focussed on performance of electrochemical gas sensors that are based on zirconia as a solid electrolyte. The paper considers sensor structures and selection of electrode materials. Impact of interfaces on sensor performance is discussed. This paper also provides a brief overview of electrochemical properties of zirconia and their effect on sensor performance. Impact of auxiliary materials on sensors performance characteristics, such as sensitivity, selectivity, response time and recovery time, is also discussed. Dual gas sensors that can be applied for simultaneous monitoring of the concentration of both oxygen and other gas phase components, are briefly considered

  19. Miniature solid-state gas compressor

    Science.gov (United States)

    Lawless, W.N.; Cross, L.E.; Steyert, W.A.

    1985-05-07

    A miniature apparatus for compressing gases is disclosed in which an elastomer disposed between two opposing electrostrictive or piezoelectric ceramic blocks, or between a single electrostrictive or piezoelectric ceramic block and a rigid surface, is caused to extrude into or recede from a channel defined adjacent to the elastomer in response to application or removal of an electric field from the blocks. Individual cells of blocks and elastomer are connected to effect a gas compression by peristaltic activation of the individual cells. The apparatus is self-valving in that the first and last cells operate as inlet and outlet valves, respectively. Preferred electrostrictive and piezoelectric ceramic materials are disclosed, and an alternative, non-peristaltic embodiment of the apparatus is described. 9 figs.

  20. Recycling of rare earths from Hg-containing fluorescent lamp scraps by solid state chlorination

    International Nuclear Information System (INIS)

    Lorenz, Tom; Froehlich, Peter; Bertau, Martin; Golon, Katja

    2015-01-01

    Solid state chlorination with NH 4 Cl comprises a method for rare earth recycling apart from pyro- or hydrometallurgical strategies. The examined partially Hg-containing fluorescent lamp scraps are rich in rare earths like La, Ce, Tb and Gd, but especially in Y and Eu. By mixing with NH 4 Cl and heating up to NH 4 Cl decomposition temperature in a sublimation reactor, Y and Eu could be transferred selectively into their respective metal chlorides with high yields. The yield and selectivity depend on temperature and the ratio of NH 4 Cl to fluorescent lamp scraps, which were varied systematically.

  1. Fluorescence line-narrowing studies of rare earths in disordered solids

    International Nuclear Information System (INIS)

    Hall, D.W.

    1982-01-01

    This dissertation is made up of two experimental studies dealing with apparently diverse topics within the subject of rare earths (RE) in solids. The first study, described in Part II, concerns the vibrations of a disordered host material about an optically active rare-earth ion as manifested by vibrationally-assisted-electronic, or vibronic transitions. Part III of the dissertation describes an investigation of the influence of site anisotropy on the purely electronic, laser transition of Nd 3+ in glass. These two studies are bound together by the common experimental technique of laser-induced fluorescence line narrowing (FLN). By exciting fluorescence with monochromatic light of well-characterized polarization, one may select and observe the response of a single subset of the optically active ions and obtain information that is usually masked by the inhomogeneous nature of disordered solids

  2. Axial dispersion of gas and solid phases in a gas—solid packed column at trickle flow

    NARCIS (Netherlands)

    Roes, A.W.M.; van Swaaij, Willibrordus Petrus Maria

    1979-01-01

    Axial dispersion of gas and solid phases in a gas—solid packed column at trickle flow, a promising new countercurrent operation, was evaluated using residence time distribution (RTD) experiments. The column was packed with dumped Pall rings, the gas phase was air at ambient conditions and the solid

  3. Integration of a municipal solid waste gasification plant with solid oxide fuel cell and gas turbine

    DEFF Research Database (Denmark)

    Bellomare, Filippo; Rokni, Masoud

    2013-01-01

    An interesting source of producing energy with low pollutants emission and reduced environmental impact are the biomasses; particularly using Municipal Solid Waste (MSW) as fuel, can be a competitive solution not only to produce energy with negligible costs but also to decrease the storage...... in landfills. A Municipal Solid Waste Gasification Plant Integrated with Solid Oxide Fuel Cell (SOFC) and Gas Turbine (GT) has been studied and the plant is called IGSG (Integrated Gasification SOFC and GT). Gasification plant is fed by MSW to produce syngas by which the anode side of an SOFC is fed wherein...

  4. CO_2 gas sensors based on rare earth oxycarbonates

    International Nuclear Information System (INIS)

    Haensch, Alexander

    2016-01-01

    This title presents a new type of CO_2 gas sensor, that allows the measurement of CO_2 gas with very low effort. The measurement principle is based on two semiconducting materials. One the ''receptor'' and a ''transducer'' form a semiconductor junction. Electronic changes in the receptor change the electrical resistance in the transducer and therefor allow the easy electrical measurement. The reactivity and the reaction mechanism is thoroughly studied. In the first part the basics and resistance measurements are presented. A comparison between different mixtures is done. The main part studies the surface chemistry with operando DRIFT spectroscopy. The chemical reactivity of different target gases and background gases is studied thoroughly. The electronic properties of Oxycarbonates and the combination of oxycarbonate and tin oxide were studied using operando Kelvin probes measurements. The result is that CO_2 alters the electron affinity of the material. Once moisture is present, an additional band bending is visible. The band bending dominated in a humid atmosphere, the work function changes. The electronic connection of oxycarbonate and tin oxide, the work function change of Oxycarbonates can be transferred to the tin oxide. Using the collected data, a basic idea of the operation will be presented by a two-semiconductor materials gas sensor.

  5. Origin of planetary primordial rare gas - The possible role of adsorption.

    Science.gov (United States)

    Fanale, F. P.; Cannon, W. A.

    1972-01-01

    The degree of physical adsorption of Ne, Ar, Kr, and Xe on pulverized samples of the Allende meteorite at 113 K has been measured. The observed pattern of equilibrium enrichment of heavy rare gases over light on the pulverized meteorite surfaces relative to the gas phase is similar to the enrichment pattern exhibited by planetary primordial rare gas when compared with the composition of solar rare gas. Results indicate that, at 113 K, a total nebular pressure of from .01 to .001 atm would be required to explain the Ar, Kr, and Xe abundances in carbonaceous chondrites with an adsorption mechanism. This pressure estimate is compatible with the range of possible nebular pressures suggested by astrophysical arguments. However, the subsequent mechanism by which initially adsorbed gas might have been transferred into the interiors of grains cannot be identified at present.

  6. Ultrasonic levitation for the examination of gas/solid reactions

    International Nuclear Information System (INIS)

    Kavouras, A.; Krammer, G.

    2003-01-01

    An experimental setup based on acoustic levitation for the examination of gas/solid reactions is presented. In this setup single particles in the diameter range 1 mm-30 μm can be held against gravity for any wanted time in a defined gas atmosphere at elevated temperatures. The change of particle size, shape, and position can be measured and recorded using an optical device, consisting of a camera and a long range microscope. Basic experiments with inert particles of different shape and solid density have shown that the axial position of a reacting particle can be employed to derive its weight change. A method to evaluate this change of the recorded position for the according weight change is proposed. Exemplary results in the context of dry flue gas cleaning using Ca(OH) 2 powder are presented. Single Ca(OH) 2 particles are exposed to a well defined gas atmosphere and after some time these particles are retrieved from the ultrasonic field for further analyses. Only an in situ measurement of the particle weight change (i.e., without removing the particle from the well defined reactive atmosphere) brings information regarding the uptake of water by the sorbent, which accompanies SO 2 and HCl absorption

  7. Adsorption of gas mixtures on heterogeneous solid surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Jaroniec, M; Rudzinski, W

    1977-01-01

    A review of theoretical studies on the physical adsorption from gas mixtures on heterogeneous solid surfaces, mainly by Jaroniec and coworkers, covers the vector notation used in the calculations; adsorption isotherms for multicomponent gases; the generalized integral equation for adsorption of gas mixtures, its numerical and analytical solutions, applied, (e.g., to interpret the experimental adsorption isotherms of ethane/ethylene on Nuxit-AL); thermodynamic relations, applied, (e.g., to calculating isosteric adsorption heats from experimental parameters for the adsorption of propylene from propane/propylene mixtures on Nuxit-AL); and the derivation and use of a simplified integral equation for describing the adsorption from gas mixtures on heterogeneous surfaces. 75 references.

  8. Low energy atomic field bremsstrahlung from thin rare gas targets

    International Nuclear Information System (INIS)

    Semaan, M.E.

    1982-01-01

    A relative measurement of the doubly-differential cross-section for electron atomic field bremsstrahling, differential in photon energy and angle is reported. Data for (d 2 sigma)/(dk dO/sub k/) have been taken for incident electron energies T ranging from 4 to 10 keV on target atoms of helium, neon, argon, krypton and xenon at a photon emission angle of 90 0 . The X-rays, produced at 90 0 to the intersection of the crossed electron and gas beams, are detected by a Si(Li) detector, having a resolution of about 200 eV at 6 keV and 0.3 mil Be window. The theoretical angular distribution (d 2 sigma)/(dk dO/sub k/) has been deduced from the photon energy spectrum by the use of the shape function S(Z,T,k,T) defined by Tseng and Pratt as S(Z,T,k,T) = [(d 2 sigma)/(dk dO/sub k/)] / [(dsigma)/(dk)]. The values of S used were obtained by an interpolation of the benchmark data provided by Pratt et al. Agreement between our experiment and the theory is measured by how well the theoretical curve fits the data. The agreement appeared to be good

  9. The effect of gas double-dynamic on mass distribution in solid-state fermentation.

    Science.gov (United States)

    Chen, Hong-Zhang; Zhao, Zhi-Min; Li, Hong-Qiang

    2014-05-10

    The mass distribution regularity in substrate of solid-state fermentation (SSF) has rarely been reported due to the heterogeneity of solid medium and the lack of suitable instrument and method, which limited the comprehensive analysis and enhancement of the SSF performance. In this work, the distributions of water, biomass, and fermentation product in different medium depths of SSF were determined using near-infrared spectroscopy (NIRS) and the developed models. Based on the mass distribution regularity, the effects of gas double-dynamic on heat transfer, microbial growth and metabolism, and product distribution gradient were systematically investigated. Results indicated that the maximum temperature of substrate and the maximum carbon dioxide evolution rate (CER) were 39.5°C and 2.48mg/(hg) under static aeration solid-state fermentation (SASSF) and 33.9°C and 5.38mg/(hg) under gas double-dynamic solid-state fermentation (GDSSF), respectively, with the environmental temperature for fermentation of 30±1°C. The fermentation production (cellulase activity) ratios of the upper, middle, and lower levels were 1:0.90:0.78 at seventh day under SASSF and 1:0.95:0.89 at fifth day under GDSSF. Therefore, combined with NIRS analysis, gas double-dynamic could effectively strengthen the solid-state fermentation performance due to the enhancement of heat transfer, the stimulation of microbial metabolism and the increase of the homogeneity of fermentation products. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Distribution of rare-earths in solid solution crandalita- goyazita of Sapucaia (Bonito-Para)

    International Nuclear Information System (INIS)

    Costa, M.L. da; Melo Costa, W.A. de

    1987-01-01

    The Crandallite are predominant in the lateritic phosphates of Sapucaia, in the form of the solid solution Crandallite (Cn)- Goyazite (Gz)-Florencite (Fl). The Crandallite-Goyazite is predominant, where the maximum proportion of Florencite is Cn 60 Cz 34.8 Fl 5.2 - This proportion of Florencite is relatively high for laterites, and for this case having up to 1,374% weight of TR 2 O 3 in the total sample. The light rare elements are predominant over the heavy ores, and are illustrated in the distribution curve normalized for the chondrites. This curve is partially comparable with the curve for Apatite presents slight negative anomaly for the element Europium, and slight positive anomaly for The elements Thulium. The geochemical caracteristics for the rare earths in this group allow the prediction for the original rock for the laterites. (author) [pt

  11. Heat transfer problems in gas-cooled solid blankets

    International Nuclear Information System (INIS)

    Fillo, J.A.; Powell, J.R.

    1976-01-01

    In all fusion reactors using the deuterium-tritium fuel cycle, a large fraction approximately 80 percent of the fusion energy will be released as approximately 14 MeV neutrons which must be slowed down in a relatively thick blanket surrounding the plasma, thereby, converting their kinetic energy to high temperature heat which can be continuously removed by a coolant stream and converted in part to electricity in a conventional power turbine. Because of the primary goal of achieving minimum radioactivity, to date Brookhaven blanket concepts have been restricted to the use of some form of solid lithium, with inert gas-cooling and in some design cases, water-cooling of the shell structure. Aluminum and graphite have been identified as very promising structural materials for fusion blankets, and conceptual designs based on these materials have been made. Depending on the thermal loading on the ''first'' wall which surrounds the plasma as well as blanket design, heat transfer problems may be noticeably different in gas-cooled solid blankets. Approaches to solution of heat removal problems as well as explanation of: (a) the after-heat problems in blankets; (b) tritium breeding in solids; and (c) materials selection for radiation shields relative to the minimum activity blanket efforts at Brookhaven are discussed

  12. Experimental solid state NMR of gas hydrates : problems and solutions

    Energy Technology Data Exchange (ETDEWEB)

    Moudrakovski, I.; Lu, H.; Ripmeester, J. [National Research Council of Canada, Ottawa, ON (Canada). Steacie Inst. for Molecular Sciences; Kumar, R.; Susilo, R. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Chemical and Biological Engineering; Luzi, M. [GeoForschungsZentrum Potsdam, Potsdam (Germany)

    2008-07-01

    Solid State NMR is a suitable spectroscopic technique for hydrate research for several reasons, including its capability to distinguish between different structural types of hydrates, its quantitative nature and potential for both in-situ and time resolved experiments. This study illustrated the applications of solid state NMR for compositional and structural studies of clathrate hydrates, with particular emphasis on experimental techniques and potential ways to overcome technical difficulties. In order to use the method to its full capacity, some instrumental developments are needed to adapt it to the specific experimental requirements of hydrate studies, such as very low temperatures and high pressures. This presentation discussed the quantification of the Carbon-13 spectra with examples from natural and synthetic hydrates prepared from multi-component mixtures of hydrocarbons. The main approach used for the first two examples was Carbon-13 NMR with Magic Angle Spinning (MAS) at -100 degrees C. The detailed characterization of mixed hydrogen hydrates required low temperature hydrogen MAS. The quantification problems encountered during these experiments were also discussed. The purpose of these recent experimental developments was to prompt wider application of Solid State NMR in hydrate research. NMR proved to be a viable method for analyzing the composition and structure of multi-component mixed gas hydrates; characterizing natural gas hydrates; and, evaluating the formation conditions and properties of mixed hydrogen hydrates. The limitations of the method were highlighted and sensible choices of experimental conditions and techniques that ensure accurate results were discussed. 34 refs., 10 figs.

  13. 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.

  14. The equivalent electrical permittivity of gas-solid mixtures at intermediate solid volume fractions.

    Energy Technology Data Exchange (ETDEWEB)

    Torczynski, John Robert; Ceccio, Steven Louis; Tortora, Paul Richard

    2005-07-01

    Several mixture models are evaluated for their suitability in predicting the equivalent permittivity of dielectric particles in a dielectric medium for intermediate solid volume fractions (0.4 to 0.6). Predictions of the Maxwell, Rayleigh, Bottcher and Bruggeman models are compared to computational simulations of several arrangements of solid particles in a gas and to the experimentally determined permittivity of a static particle bed. The experiment uses spherical glass beads in air, so air and glass permittivity values (1 and 7, respectively) are used with all of the models and simulations. The experimental system used to measure the permittivity of the static particle bed and its calibration are described. The Rayleigh model is found to be suitable for predicting permittivity over the entire range of solid volume fractions (0-0.6).

  15. Solid adsorbents for removal of hydrogen sulphide from hot gas

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E.; Yumura, Motoo

    1986-04-01

    A wide range of solids have been tested as potential adsorbents for H/sub 2/S removal from hot gas. These solids can be divided into two main groups, i.e., the adsorbents containing alkaline earth metals and those containing transition metals. Among the former, calcium oxide and naturally occurring materials such as limestone, dolomite and calcium silicate have attracted a great deal of attention. The adsorbents of the second group include iron oxide alone or in combination with some supports, zinc oxide, zinc ferrite and manganese oxide. The materials containing both the alkaline earth metals and transition metals, e.g., manganese nodules, fly ash and the reject from the aluminium industry (red mud) have been evaluated as well.

  16. Transmission electron microscope examination of rare-gas bubbles in metals: analysis of observed contrast effects

    International Nuclear Information System (INIS)

    Levy, V.

    1964-01-01

    Metallic samples containing rare gas bubbles have been examined by transmission electron microscopy. The different features of the contrast patterns of the bubbles have been explained by the dynamical theory of contrast, assuming that the bubble behaves as a hole in the metal. Experimental results are in good agreement with the theory. (author) [fr

  17. Gas-Solid Reaction Properties of Fluorine Compounds and Solid Adsorbents for Off-Gas Treatment from Semiconductor Facility

    Directory of Open Access Journals (Sweden)

    Shinji Yasui

    2012-01-01

    Full Text Available We have been developing a new dry-type off-gas treatment system for recycling fluorine from perfluoro compounds present in off-gases from the semiconductor industry. The feature of this system is to adsorb the fluorine compounds in the exhaust gases from the decomposition furnace by using two types of solid adsorbents: the calcium carbonate in the upper layer adsorbs HF and converts it to CaF2, and the sodium bicarbonate in the lower layer adsorbs HF and SiF4 and converts them to Na2SiF6. This paper describes the fluorine compound adsorption properties of both the solid adsorbents—calcium carbonate and the sodium compound—for the optimal design of the fixation furnace. An analysis of the gas-solid reaction rate was performed from the experimental results of the breakthrough curve by using a fixed-bed reaction model, and the reaction rate constants and adsorption capacity were obtained for achieving an optimal process design.

  18. Conformational cooling and conformation selective aggregation in dimethyl sulfite isolated in solid rare gases

    OpenAIRE

    Borba, Ana; Gómez-Zavaglia, Andrea; Fausto, Rui

    2006-01-01

    Dimethyl sulfite has three conformers of low energy, GG, GT and GG0, which have significant populations in the gas phase at room temperature. According to theoretical predictions, the GT and GG0 conformers are higher in energy than the GG conformer by 0.83 and 1.18 kJ molK1, respectively, while the barriers associated with the GG0/GT and GT/GG isomerizations are 1.90 and 9.64 kJ molK1, respectively. Experimental data obtained for the compound isolated in solid argon, krypton and xenon demonst...

  19. Collisions of halogen (2P) and rare gas (1S) atoms

    International Nuclear Information System (INIS)

    Becker, C.H.

    1978-12-01

    Differential cross sections I (THETA) at several collision energies measured in crossed molecular beam experiments are reported for several combinations of halogen atoms ( 2 P) scattered off rare gas-rare gas atoms ( 1 S 0 ), namely, F + Ne, F + Ar, F + Kr, F + Xe, C1 + Xe. The scattering is described by an elastic model appropriate to Hund's case c coupling. With the use of this model, the X 1/2, I 3/2, and II 1/2 interaction potential energy curves are derived by fitting calculated differential cross sections, based on analytic representations of the potentials, to the data. The F - Xe X 1/2 potential shows a significant bonding qualitatively different than for the other F-rare gases. The I 3/2 and II 1/2 potentials closely resemble the van der Waals interactions of the one electron richer ground state rare gas-rare gas systems. Coupled-channel scattering calculations are carried out for F + Ar, F + Xe, and C1 + Xe using the realistic potential curves derived earlier. The results justify the use of the elastic model, and give additional information on intramultiplet and intermultiplet transitions. The transitions are found to be governed by the crossing of the two Ω = 1/2 potentials in the complex plane. The measured I (theta) and I (THETA) derived from the coupled-channel computations show small oscillations or perturbations (Stueckelberg oscillations) though quantitative agreement is not obtained.The nature of the anomalous F - Xe X 1/2 potential is discussed as is the approximation of a constant spin orbit coupling over the experimentally accessible range of internuclear distances for these open shell molecules. 55 references

  20. Recent advances in rare earth doped alkali-alkaline earth borates for solid state lighting applications

    Science.gov (United States)

    Verma, Shefali; Verma, Kartikey; Kumar, Deepak; Chaudhary, Babulal; Som, Sudipta; Sharma, Vishal; Kumar, Vijay; Swart, Hendrik C.

    2018-04-01

    As a novel class of inorganic phosphor, the alkali-alkaline earth borate phosphors have gained huge attention due to their charming applications in solid-state lighting (SSL) and display devices. The current research drive shows that phosphors based on the alkali-alkaline earth borates have transformed the science and technology due to their high transparency over a broad spectral range, their flexibility in structure and durability for mechanical and high-laser applications. Recent advances in various aspects of rare-earth (RE) doped borate based phosphors and their utilizations in SSL and light emitting diodes are summarized in this review article. Moreover, the present status and upcoming scenario of RE-doped borate phosphors were reviewed in general along with the proper credential from the existing literature. It is believed that this review is a sole compilation of crucial information about the RE-doped borate phosphors in a single platform.

  1. Kinetic analysis of rare gas metastable production and optically pumped Xe lasers

    Science.gov (United States)

    Demyanov, A. V.; Kochetov, I. V.; Mikheyev, P. A.; Azyazov, V. N.; Heaven, M. C.

    2018-01-01

    Optically pumped all-rare-gas lasers use metastable rare gas atoms as the lasing species in mixtures with He or Ar buffer gas. The metastables are generated in a glow discharge, and we report model calculations for the optimal production of Ne*, Ar*, Kr* and Xe*. Discharge efficiency was estimated by solving the Boltzmann equation. Laser efficiency, gain and output power of the CW optically pumped Xe laser were assessed as functions of heavier rare gas content, pressure, optical pump intensity and the optical path length. It was found that, for efficient operation the heavier rare gas content has to be of the order of one percent or less, and the total pressure—in the range 0.3-1.5 atm. Output power and specific discharge power increase approximately linearly with pump intensity over the output range from 300-500 W cm-2. Ternary mixtures Xe:Ar:He were found to be the most promising. Total laser efficiency was found to be nearly the same for pumping the 2p8 or 2p9 state, reaching 61%-70% for a pump intensity of ~720 W cm-2 when the Xe fraction was in the range 0.001 ÷ 0.01 and Ar fraction—0.1 ÷ 0.5. However, when the 2p8 state was pumped, the maximum total efficiency occurred at larger pressures than for pumping of the 2p9 state. The discharge power density required to sustain a sufficient Xe* number density was in the range of tens of watts per cubic centimeter for 50% Ar in the mixture.

  2. Unusual seeding mechanism for enhanced performance in solid-phase magnetic extraction of Rare Earth Elements

    Science.gov (United States)

    Polido Legaria, Elizabeth; Rocha, Joao; Tai, Cheuk-Wai; Kessler, Vadim G.; Seisenbaeva, Gulaim A.

    2017-03-01

    Due to the increasing demand of Rare Earth Elements (REE or RE), new and more efficient techniques for their extraction are necessary, suitable for both mining and recycling processes. Current techniques such as solvent extraction or solid adsorbents entail drawbacks such as using big volumes of harmful solvents or limited capacity. Hybrid nanoadsorbents based on SiO2 and highly stable γ-Fe2O3-SiO2 nanoparticles, proved recently to be very attractive for adsorption of REE, yet not being the absolute key to solve the problem. In the present work, we introduce a highly appealing new approach in which the nanoparticles, rather than behaving as adsorbent materials, perform as inducers of crystallization for the REE in the form of hydroxides, allowing their facile and practically total removal from solution. This induced crystallization is achieved by tuning the pH, offering an uptake efficiency more than 20 times higher than previously reported (up to 900 mg RE3+/g vs. 40 mg RE3+/g). The obtained phases were characterized by SEM-EDS, TEM, STEM and EFTEM and 13C and 29Si solid state NMR. Magnetic studies showed that the materials possessed enough magnetic properties to be easily removed by a magnet, opening ways for an efficient and industrially applicable separation technique.

  3. Momentum distributions of selected rare-gas atoms probed by intense femtosecond laser pulses

    DEFF Research Database (Denmark)

    Abu-Samha, Mahmoud; Madsen, Lars Bojer

    2011-01-01

    We provide a direct comparison between numerical and experimental (Rudenko et al 2004 J. Phys. B: At. Mol. Opt. Phys. 37 L407) photoelectron momentum distributions in strong-field ionization of selected rare-gas atoms (He, Ne and Ar), probed by femtosecond linearly polarized laser pulses. The cal......We provide a direct comparison between numerical and experimental (Rudenko et al 2004 J. Phys. B: At. Mol. Opt. Phys. 37 L407) photoelectron momentum distributions in strong-field ionization of selected rare-gas atoms (He, Ne and Ar), probed by femtosecond linearly polarized laser pulses....... The calculations are performed by solving the time-dependent Schrödinger equation within the single-active-electron approximation, and focal-volume effects are taken into account by appropriately averaging the results. The resulting momentum distributions are in quantitative agreement with the experimental...

  4. Medium-induced change of the optical response of metal clusters in rare-gas matrices

    Science.gov (United States)

    Xuan, Fengyuan; Guet, Claude

    2017-10-01

    Interaction with the surrounding medium modifies the optical response of embedded metal clusters. For clusters from about ten to a few hundreds of silver atoms, embedded in rare-gas matrices, we study the environment effect within the matrix random phase approximation with exact exchange (RPAE) quantum approach, which has proved successful for free silver clusters. The polarizable surrounding medium screens the residual two-body RPAE interaction, adds a polarization term to the one-body potential, and shifts the vacuum energy of the active delocalized valence electrons. Within this model, we calculate the dipole oscillator strength distribution for Ag clusters embedded in helium droplets, neon, argon, krypton, and xenon matrices. The main contribution to the dipole surface plasmon red shift originates from the rare-gas polarization screening of the two-body interaction. The large size limit of the dipole surface plasmon agrees well with the classical prediction.

  5. Fixing arsenic contained in a gas phase using solid hematite

    International Nuclear Information System (INIS)

    Balladares, E.; Gonzalez, A.; Rarra, R.; Sanchez, M.

    2004-01-01

    Feasibility to obtain ferric arsenate starting from arsenic containing gas in contact with Fe 3 O 3 has been studied. Thermodynamic stability of the system Fe-As-O was analysed in order to verify conditions to form Fe x As y O z type compounds. Experiments were made using a hematite sample suspended in a thermogravimetric device. As 4 O 6 was generated starting from solid As 2 O 3 which was circulating through the iron oxide. Final samples were analysed chemically and by means of DRX, verifying the formation of FeAsO 4 , FeAsO 4 .2h 2 O and FeAsO 4 .(H 2 O) 2 in small quantities. Tests in porous bed and pellets were carried out, studying the effect of: porosity, temperature and oxygen potential. The largest conversion obtained was 10% at 800 degree centigrade, pO 2 =50% and porosity=0.883. (Author) 9 refs

  6. Landfill gas from solid urban waste - an opportunity evaluation

    International Nuclear Information System (INIS)

    Gramatikov, Plamen; Kovachev, Vassil; Gramatikova, Marija

    2004-01-01

    The problems (technical, economic, social etc.) which have to be solved by municipal waste treatment, especially in Central/East European towns, are discussed in this work. Percentages of products and calorific values of the main solid organic wastes are estimated. Different urban waste utilisation methods - Landfills Anaerobic digestion, Incineration, Refuse-derived fuels, Pyrolysis and Gasification are comment in this paper. These methods are compared using the town of Blagoevgrad (Bulgaria) as an example. It is round that a well established landfill gas production technology offers simplicity of collection (such as is practised in most of low and moderately developed countries like Bulgaria), relatively simple operation and maintenance, improvement of the environmental protection and of the energy production (based on the local disposal and renewable energy sources) and is more feasible for the East European urban concentrations. (Author)

  7. Spectroscopic and Kinetic Measurements of Alkali Atom-Rare Gas Excimers

    Science.gov (United States)

    2009-11-04

    vapors – Exciplex molecules absorb over much greater bandwidth • Control of inherent high optical gain to minimize ASE and optimize laser oscillation... Exciplex assisted diode Pumped Alkali Laser (XPAL) • Education of a future generation of laser scientists VG09-227-2 Physical Sciences Inc. Novel Approach...This new laser exploits the optical properties of weakly-bound alkali/rare-gas exciplexes for pumping the 2P1/2, 3/2 alkali atomic excited states 4

  8. Solid-solid and gas-solid interactions induced during high-energy milling to produce PbTe nanopowders

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Chavez, H., E-mail: rojas_hugo@ittlahuac2.edu.mx [Instituto Tecnologico de Tlahuac - II (Mexico); Reyes-Carmona, F. [Facultad de Quimica - UNAM (Mexico); Garibay-Febles, V. [Instituto Mexicano del Petroleo, Laboratorio de Microscopia Electronica de Ultra Alta Resolucion (Mexico); Jaramillo-Vigueras, D. [Centro de Investigacion e Innovacion Tecnologica - IPN (Mexico)

    2013-05-15

    Transformations from precursors to nanoparticles by high-energy milling are promoted by two major driving forces, namely physical and/or chemical. While the former has been difficult to trace since stress, strain and recovery may occur almost simultaneously during milling, the latter has been sequentially followed as an evolution from precursors to intermediate phases and thereof to high purity nanocrystals. The specific objective of this work is to discern how solid-solid and partially solid-gas reactions manifest themselves correspondingly as a short-range diffusion through an interface or how vapor species, as a subliming phenomenon, grows as a different phase on an active local surface. These series of changes were traced by sub-cooling the as-milled powders extracted during a milling cycle. Through this experimental technique, samples were electron microscopically analyzed and where it was required, selected area electron diffraction images were obtained. High-resolution transmission electron microscopy results, unambiguously, confirm that nanocrystals in the last stage show a cubic morphology which average size distributions are around 17 nm.

  9. Diversity and dynamics of dominant and rare bacterial taxa in replicate sequencing batch reactors operated under different solids retention time

    KAUST Repository

    Bagchi, Samik

    2014-10-19

    In this study, 16S rRNA gene pyrosequencing was applied in order to provide a better insight on the diversity and dynamics of total, dominant, and rare bacterial taxa in replicate lab-scale sequencing batch reactors (SBRs) operated at different solids retention time (SRT). Rank-abundance curves showed few dominant operational taxonomic units (OTUs) and a long tail of rare OTUs in all reactors. Results revealed that there was no detectable effect of SRT (2 vs. 10 days) on Shannon diversity index and OTU richness of both dominant and rare taxa. Nonmetric multidimensional scaling analysis showed that the total, dominant, and rare bacterial taxa were highly dynamic during the entire period of stable reactor performance. Also, the rare taxa were more dynamic than the dominant taxa despite expected low invasion rates because of the use of sterile synthetic media.

  10. Experimental and theoretical studies on the gas/solid/gas transformation cycle in extraterrestrial environments

    Science.gov (United States)

    Cottin, Hervé; Gazeau, Marie-Claire; Chaquin, Patrick; Raulin, François; Bénilan, Yves

    2001-12-01

    The ubiquity of molecular material in the universe, from hydrogen to complex organic matter, is the result of intermixed physicochemical processes that have occurred throughout history. In particular, the gas/solid/gas phase transformation cycle plays a key role in chemical evolution of organic matter from the interstellar medium to planetary systems. This paper focuses on two examples that are representative of the diversity of environments where such transformations occur in the Solar System: (1) the photolytic evolution from gaseous to solid material in methane containing planetary atmospheres and (2) the degradation of high molecular weight compounds into gas phase molecules in comets. We are currently developing two programs which couple experimental and theoretical studies. The aim of this research is to provide data necessary to build models in order to better understand (1) the photochemical evolution of Titan's atmosphere, through a laboratory program to determine quantitative spectroscopic data on long carbon chain molecules (polyynes) obtained in the SCOOP program (French acronym for Spectroscopy of Organic Compounds Oriented for Planetology), and (2) the extended sources in comets, through a laboratory program of quantitative studies of photochemical and thermal degradation processes on relevant polymers (e.g., Polyoxymethylene) by the SEMAPhOrE Cometaire program (French acronym for Experimental Simulation and Modeling Applied to Organic Chemistry in Cometary Environment).

  11. Study on Fluid-solid Coupling Mathematical Models and Numerical Simulation of Coal Containing Gas

    Science.gov (United States)

    Xu, Gang; Hao, Meng; Jin, Hongwei

    2018-02-01

    Based on coal seam gas migration theory under multi-physics field coupling effect, fluid-solid coupling model of coal seam gas was build using elastic mechanics, fluid mechanics in porous medium and effective stress principle. Gas seepage behavior under different original gas pressure was simulated. Results indicated that residual gas pressure, gas pressure gradient and gas low were bigger when original gas pressure was higher. Coal permeability distribution decreased exponentially when original gas pressure was lower than critical pressure. Coal permeability decreased rapidly first and then increased slowly when original pressure was higher than critical pressure.

  12. Correlation dimension estimate and its potential use in analysis of gas-solid flows

    DEFF Research Database (Denmark)

    Yin, Chungen; Rosendahl, Lasse Aistrup; Kær, Søren Knudsen

    2005-01-01

    Gas-solid flows are nonlinear systems. Therefore state-space analysis, a tool developed within the framework of nonlinear dynamics, could provide more useful insights into complex gas-solid flows. One of the positive aspects of state-space analysis is that the major properties of a system can be ...

  13. Rare gas systematics: Formation of the atmosphere, evolution and structure of the Earth's mantle

    International Nuclear Information System (INIS)

    Allegre, C.J.; Staudacher, T.; Sarda, P.; Paris-6 Univ., 75; Paris-7 Univ., 75

    1987-01-01

    To explain the rare gas content and isotopic composition measured in modern terrestrial materials we explore in this paper an Earth model based on four reservoirs: atmosphere, continental crust, upper mantle and lower mantle. This exploration employs three tools: mass balance equations, the concept of mean age of outgassing and the systematic use of all of the rare gases involving both absolute amount and isotopic composition. The results obtained are as follows: half of the Earth's mantle is 99% outgassed. Outgassing occurred in an early very intense stage within the first 50 Ma of Earth history and a slow continuous stage which continues to the present day. The mean age of the atmosphere is 4.4 Ga. Our model with four main reservoirs explains quantitatively both isotopic and chemical ratios, assuming that He migrates from the lower to the upper mantle whereas the heavy rare gases did not. Noble gas fluxes for He, Ar and Xe from different reservoirs have been estimated. The results constrain the K content in the earth to 278 ppm. Several geodynamic consequences are discussed. (orig.)

  14. A study on rare gas - oxygen reactions excited by low temperature plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Hiroaki; Kiuchi, Kiyoshi; Saburi, Tei; Fukaya, Kiyoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    The concentration of radioactive rare gases like Xe and Kr in nuclear fuels on PWRs and BWRs increases promptly with dependent on the burn-up ratio. These gases are affect to the long performance of nuclear fuel elements due to accumulate in gap between cladding and fuel, because it has the low thermal conductivity. It is also required to develop the practical means to correct these gases including in the off-gas in nuclear plants for inhibiting the environmental pollution. On the present study, we carried out the fundamental research to evaluate the chemical reactivity of these gases under heavy irradiation. We proposed the new excitation mechanism of these gases by expecting the formation of low energy plasma under irradiation. The chemical reactivity on rare gas-oxygen system was examined by using the low energy plasma driven reaction apparatus installed the RF excitation source. The density of electrons and lower pressure limit for the RF excitation was depended on the ionization energy of each gas. It is clarified that Xe is easy to form gaseous oxide due to the high excitation efficiency in low energy plasma. (author)

  15. Some aspects of the interaction of photons and electrons with rare gas atoms

    International Nuclear Information System (INIS)

    Westerveld, W.B.

    1979-01-01

    Processes for excitation in rare gas atoms are described, due to absorption of photons and bombardment with electrons. The differences and similarities between excitation by absorption of light (spectroscopy) and by electron impact (collision physics) are qualified. Oscillator strengths from the self-absorption of resonance radiation in rare gases are determined. The excitation of 2'P and 3'P states of helium by electrons has been studied by observing excitation cross sections and polarization fractions obtained from XUV radiation. A description is given of a recently completed apparatus to study inelastic electron-atom scattering processes by coincidence techniques. An introduction is given to the theory which relates the parameters describing an excited state of an atom to the angular distribution of the radiation emitted in the decay of the excited state. (Auth.)

  16. High Temperature Gas-to-Gas Heat Exchanger Based on a Solid Intermediate Medium

    Directory of Open Access Journals (Sweden)

    R. Amirante

    2014-04-01

    Full Text Available This paper proposes the design of an innovative high temperature gas-to-gas heat exchanger based on solid particles as intermediate medium, with application in medium and large scale externally fired combined power plants fed by alternative and dirty fuels, such as biomass and coal. An optimization procedure, performed by means of a genetic algorithm combined with computational fluid dynamics (CFD analysis, is employed for the design of the heat exchanger: the goal is the minimization of its size for an assigned heat exchanger efficiency. Two cases, corresponding to efficiencies equal to 80% and 90%, are considered. The scientific and technical difficulties for the realization of the heat exchanger are also faced up; in particular, this work focuses on the development both of a pressurization device, which is needed to move the solid particles within the heat exchanger, and of a pneumatic conveyor, which is required to deliver back the particles from the bottom to the top of the plant in order to realize a continuous operation mode. An analytical approach and a thorough experimental campaign are proposed to analyze the proposed systems and to evaluate the associated energy losses.

  17. Gas-solid alkali destruction of volatile chlorocarbons

    International Nuclear Information System (INIS)

    Foropoulos, J. Jr.

    1995-12-01

    Many chlorocarbons are environmental dangers and health hazards. The simplest perchlorinated hydrocarbon, carbon tetrachloride, is near the top of the list of hazardous compounds. Carbon tetrachloride was used as a cleaning fluid, solvent, and fire-extinguishing agent. The nuclear and defense complexes also employed great quantities of carbon tetrachloride and other chlorocarbons as cleaning and degreasing agents. Many sites nationwide have underground chlorocarbon contamination plumes. Bulk chlorocarbon inventories at many locations await treatment and disposal. Often the problem is compounded by the chlorocarbon being radioactively contaminated. Waste inventory and groundwater contamination problems exist for many other chlorocarbons, especially methylene chloride, chloroform, and tri- and tetrachloroethylene. In this work solid soda lime (a fused mixture of approximately 95% CaO and 5% NaOH in a coarse, granulated form) at 350 C to 400 C acts as the hydrolyzing degradation, and off-gas scrubbing medium. Within soda lime CO 2 and HCl from hydrolysis and degradation convert immediately to calcium and sodium chlorides and carbonates, with water vapor as a volatile byproduct

  18. Orbital alignment effects in near-resonant Rydberg atoms-rare gas collisions

    International Nuclear Information System (INIS)

    Isaacs, W.A.; Morrison, M.A.

    1993-01-01

    Recent experimental and theoretical studies of near-resonant energy transfer collisions involving rare-gas atoms and alkali or alkaline earth atoms which have been initially excited to an aligned state via one or more linearly polarized rasters have yielded a wealth of insight into orbital alignment and related effects. We have extended this inquiry to initially aligned Rydberg states, examining state-to-state and alignment-selected cross sections using quantum collision theory augmented by approximations appropriate to the special characteristics of the Rydberg state (e.g., the quasi-free-electron model and the impulse approximation)

  19. Solid-Gas Coupling Model for Coal-Rock Mass Deformation and Pressure Relief Gas Flow in Protection Layer Mining

    OpenAIRE

    Zhu, Zhuohui; Feng, Tao; Yuan, Zhigang; Xie, Donghai; Chen, Wei

    2018-01-01

    The solid-gas coupling model for mining coal-rock mass deformation and pressure relief gas flow in protection layer mining is the key to determine deformation of coal-rock mass and migration law of pressure relief gas of protection layer mining in outburst coal seams. Based on the physical coupling process between coal-rock mass deformation and pressure-relief gas migration, the coupling variable of mining coal-rock mass, a part of governing equations of gas seepage field and deformation fiel...

  20. Collisional energy dependence of molecular ionization by metastable rare gas atoms

    International Nuclear Information System (INIS)

    Martin, R.M.; Parr, T.P.

    1979-01-01

    The collisional energy dependence of several molecular total ionization cross sections by metastable rare gas atoms was studied over the thermal energy region using the crossed molecular beam time-of-flight method. Results are reported for the collision systems He, Ne, and Ar ionizing the geometric isomers cis- and trans-dichloroethylene and ortho- and para-dichlorobenzene. The He ionization cross sections oscillate about an energy dependence of E/sup -1/2/ over the energy range 0.004--1.0 eV, and the Ar*+para-dichlorobenzene cross section oscillates about an energy dependence of E/sup -2/5/ over the energy range 0.011--0.64 eV. The remaining systems are characterized by ''bent'' E/sup -m/ dependences with m values of 0.56--0.70 at low energies changing to 0.07--0.29 at higher energies. Comparison with the slopes of the He* systems and the Ar*+para-dichlorobenzene system shows that the ''bent'' and ''oscillating'' energy dependences are similar except for the form of the cross section functions at the lowest energies. No systematic differences are found between the cross section energy dependences for ionization of different geometric isomers or for ionization by the different metastable rare gas atoms

  1. Non-additive non-interacting kinetic energy of rare gas dimers

    Science.gov (United States)

    Jiang, Kaili; Nafziger, Jonathan; Wasserman, Adam

    2018-03-01

    Approximations of the non-additive non-interacting kinetic energy (NAKE) as an explicit functional of the density are the basis of several electronic structure methods that provide improved computational efficiency over standard Kohn-Sham calculations. However, within most fragment-based formalisms, there is no unique exact NAKE, making it difficult to develop general, robust approximations for it. When adjustments are made to the embedding formalisms to guarantee uniqueness, approximate functionals may be more meaningfully compared to the exact unique NAKE. We use numerically accurate inversions to study the exact NAKE of several rare-gas dimers within partition density functional theory, a method that provides the uniqueness for the exact NAKE. We find that the NAKE decreases nearly exponentially with atomic separation for the rare-gas dimers. We compute the logarithmic derivative of the NAKE with respect to the bond length for our numerically accurate inversions as well as for several approximate NAKE functionals. We show that standard approximate NAKE functionals do not reproduce the correct behavior for this logarithmic derivative and propose two new NAKE functionals that do. The first of these is based on a re-parametrization of a conjoint Perdew-Burke-Ernzerhof (PBE) functional. The second is a simple, physically motivated non-decomposable NAKE functional that matches the asymptotic decay constant without fitting.

  2. Aqueous Rare Earth Element Patterns and Concentration in Thermal Brines Associated With Oil and Gas Production

    Energy Technology Data Exchange (ETDEWEB)

    Nye, Charles [University of Wyoming; Quillinan, Scott Austin [University of Wyoming; Neupane, Ghanashyam [Idaho National Lab. (INL), Idaho Falls, ID (United States); McLing, Travis [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-02-13

    This study is part of a joint effort by the University of Wyoming (UW) School of Energy Resources (SER), the UW Engineering Department, Idaho National Laboratories (INL), and the United States Geological Survey (USGS) to describe rare earth element concentrations in oil and gas produced waters and in coal-fired power station ash ponds. In this work we present rare earth element (REE) and trace metal behavior in produced water from four Wyoming oil and gas fields and surface ash pond water from two coal-fired power stations. The concentration of REEs in oil and gas produced waters is largely unknown. For example, of the 150,000 entries in the USGS National Produced Waters Geochemical Database less than 5 include data for REEs. Part of the reason for this scarcity is the analytical challenge of measuring REEs in high salinity, hydrocarbon-bearing waters. The industry standard for water analysis struggles to detect REEs in natural waters under ideal conditions. The detection of REEs in oil and gas field samples becomes all but impossible with the background noise and interferences caused by high concentrations of non-REE ions and residual hydrocarbons. The INL team members have overcome many of these challenges (e.g. McLing, 2014), and continue to develop their methods. Using the methods of the INL team members we measured REEs in high salinity oil and gas produced waters. Our results show that REEs exist as a dissolved species in all waters measured for this project, typically within the parts per trillion range. The samples may be grouped into two broad categories analytically, and these categories match their genesis: Wyoming oil and gas brines contain elevated levels of Europium, and Wyoming industrial pond waters show elevation in heavy REEs (HREEs). While broadly true, important variations exist within both groups. In the same field Europium can vary by more than an order of magnitude, and likewise HREEs in industrial ponds at the same site can vary by more than

  3. Ion mobilities in Xe/Ne and other rare-gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Piscitelli, D; Pitchford, L C [Centre de Physique des Plasmas et Applications de Toulouse (CPAT), UMR 5002 CNRS, 118 route de Narbonne, 31062 Toulouse (France); Phelps, A V [JILA, University of Colorado and National Institute of Technology, Boulder, Colorado (United States); Urquijo, J de [Centro de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Post Office Box 48-3, 62251, 80309-0440 Cuernavaca, Moreno (Mexico); Basurto, E [Departmento de Ciencias Basicas, Universidad Autonoma Metropolitana, 02200 Mexico Distrito Federal (Mexico)

    2003-10-01

    The ion mobility or drift velocity data important for modeling glow discharges in rare gas mixtures are not generally available, nor are the ion-neutral scattering cross sections needed to calculate these data. In this paper we propose a set of cross sections for Xe{sup +} and Ne{sup +} collisions with Xe and Ne atoms. Ion mobilities at 300 K calculated using this cross section set in a Monte Carlo simulation are reported for reduced field strengths, E/N, up to 1500x10{sup -21} V m{sup 2}, in pure gases and in Xe/Ne mixtures containing 5% and 20% Xe/Ne, which are mixtures of interest for plasma display panels (PDPs). The calculated Xe{sup +} mobilities depend strongly on the mixture composition, but the Ne{sup +} mobility varies only slightly with increasing Xe in the mixture over the range studied here. The mobilities in pure gases compare well with available experimental values, and mobilities in gas mixtures at low E/N compare well with our recent measurements which will be published separately. Results from these calculations of ion mobilities are used to evaluate the predictions of Blanc's law and of the mixture rule proposed by Mason and Hahn [Phys. Rev. A 5, 438 (1972)] for determining the ion mobilities in mixtures from a knowledge of the mobilities in each of the pure gases. The mixture rule of Mason and Hahn is accurate to better than 10% at high field strengths over a wide range of conditions of interest for modeling PDPs. We conclude that a good estimate of ion mobilities at high E/N in Xe/Ne and other binary rare gas mixtures can be obtained using this mixture rule combined with known values of mobilities in parent gases and with the Langevin form for mobility of rare gas ions ion in other gases. This conclusion is supported by results in Ar/Ne mixtures which are also presented here.

  4. Conformational cooling and conformation selective aggregation in dimethyl sulfite isolated in solid rare gases

    Science.gov (United States)

    Borba, Ana; Gómez-Zavaglia, Andrea; Fausto, Rui

    2006-08-01

    Dimethyl sulfite has three conformers of low energy, GG, GT and GG', which have significant populations in the gas phase at room temperature. According to theoretical predictions, the GT and GG' conformers are higher in energy than the GG conformer by 0.83 and 1.18 kJ mol -1, respectively, while the barriers associated with the GG'→GT and GT→GG isomerizations are 1.90 and 9.64 kJ mol -1, respectively. Experimental data obtained for the compound isolated in solid argon, krypton and xenon demonstrated that the GG'→GT energy barrier is low enough to allow an extensive conversion of the GG' form into the GT conformer during deposition of the matrices, the extent of the conversion increasing along the series Argas is used the GG'→GT conversion during deposition of the matrix is complete even at 10 K. Annealing of the argon and krypton matrices shows that the increase of the temperature of the matrix first promotes the GG'→GT isomerization, and only at higher temperatures the GT→GG conversion starts to occur, in consonance with the relative energy barriers associated with these two processes. The results also indicate that dimethyl sulfite exhibits conformation selective aggregation, with the most stable form, which has the highest dipole moment, aggregating more easily than the remaining experimentally relevant conformers (GT and GG').

  5. Rare gas constraints on the history of Boulder 1, Station 2, Apollo 17

    International Nuclear Information System (INIS)

    Leich, D.A.; Kahl, S.B.; Kirschbaum, A.R.; Niemeyer, S.; Phinney, D.

    1975-01-01

    Rare gas isotopic analyses have been performed on both pile-irradiated and unirradiated samples from Boulder 1, Station 2. Two samples from rock 72255, the Civet Cat clast and a sample of adjacent breccia, have concordant 40 Ar- 39 Ar ages of 3.99 +- 0.03 b.y. and 4.01 +- 0.03 b.y., respectively. Several samples from rock 72275 have complex thermal release patterns with no datable features, but an intermediate temperature plateau from the dark rim material of the Marble Cake clast yields an age of 3.99 +- 0.03 b.y., indistinguishable from the age of rock 72255. We regard these ages as upper limits on the time of the Serenitatis basin-forming event. The absence of fossil solar-wind trapped gases in the breccia samples implies that a prior existence for the boulder as near-surface regolith material can be regarded as extremely unlikely. Instead, the small trapped rare-gas components have isotopic and elemental compositions diagnostic of the terrestrial-type trapped component which has previously been identified in several Apollo 16 breccias and in rock 14321. Excess fission Xe is found in all Boulder 1 samples in approximately 1:1 proportions with Xe from spontaneous fission of 238 U. This excess fission Xe is attributed to spontaneous fission of 244 Pu in situ. Cosmic-ray exposure ages for samples from rocks 72215 and 72255 are concordant with mean 81 Kr-Kr exposure ages of 41.4 +- 1.4 m.y. and 44.1 +- 3.3 m.y., respectively. However, a distinctly different 81 Kr-Kr exposure age of 52.5 +- 1.4 m.y. is obtained for samples from rock 72275. A two-stage exposure model is developed to account for this discordance and for the remaining cosmogenic rare-gas data. The first stage was initiated at least 55 m.y. ago, probably as a result of the excavation of the boulder source-crop. A discrete change in shielding depths approx. 35 m.y. ago probably corresponds to the dislodgement of Boulder 1 from the South Massif and emplacement in its present position

  6. Modelling Gas Adsorption in Porous Solids: Roles of Surface ...

    Indian Academy of Sciences (India)

    Modelling the adsorption of small molecule gases such as N2, CH4 and CO2 in porous solids can ... fusive properties of CO2 adsorbed in the solids have been examined using ..... exhibit a wide range of physical behavior.78,79 The intro-.

  7. Acoustic probe for solid-gas-liquid suspensions. 1998 annual progress report

    International Nuclear Information System (INIS)

    Greenwood, M.S.; Sangani, A.S.; Tavlarides, L.L.

    1998-01-01

    'The proposed research will develop an acoustic probe for monitoring particle size and volume fraction in slurries in the absence and presence of gas. The goals are to commission and verify the probe components and system operation, develop theory for the forward and inverse problems for acoustic wave propagation through a three phase medium, and experimentally verify the theoretical analysis. The acoustic probe will permit measurement of solid content in gas-liquid-solid waste slurries in tanks across the DOE complex.'

  8. Experimental study of single-electron loss by Ar+ ions in rare-gas atoms

    Science.gov (United States)

    Reyes, P. G.; Castillo, F.; Martínez, H.

    2001-04-01

    Absolute differential and total cross sections for single-electron loss were measured for Ar+ ions on rare-gas atoms in the laboratory energy range of 1.5 to 5.0 keV. The electron loss cross sections for all the targets studied are found to be in the order of magnitude between 10-19 and 10-22 cm2, and show a monotonically increasing behaviour as a function of the incident energy. The behaviour of the total single-electron loss cross sections with the atomic target number, Zt, shows different dependences as the collision energy increases. In all cases the present results display experimental evidence of saturation in the single-electron loss cross section as the atomic number of the target increases.

  9. Study on charge transfer reaction of several organic molecules with accelerated rare gas ions

    International Nuclear Information System (INIS)

    Takahasi, Makoto; Okuda, Sachiko; Arai, Eiichi; Ichinose, Akira; Takakubo, Masaaki.

    1984-01-01

    Observing the charge transfer mass spectra of ethylbenzene, cyclobutane and methanol in Ar and Xe ion impacts, we investigated the dependence of the secondary ion peak intensities (normalized to primary ion current and target pressure) on the translational energy of primary ions (0-3500 eV).In the case of ethylbenzene, several maxima of the secondary i on peak intensities were observed in Ar and Xe ion impacts. The correlation between the maxima and the primary ion energy was examined in terms of near adiabatic theory of Massey. Supplementary studies on the energy distribution of primary ion, charge transfer cross section between methanol and Xe ion, and final product analysis in rare gas ion irradiation on cyclobutane were described. (author)

  10. Reactive Gas Solids Flow in Circulating Fluidised Beds

    DEFF Research Database (Denmark)

    Hjertager, Bjørn Helge; Solberg, Tron; Hansen, Kim Granly

    2005-01-01

    Progress in modelling and simulation of flow processes in gas/particle systems carried out at the authors? research group are presented. Emphasis is given to computational fluid dynamics (CFD) models that use the multi-dimensional multi fluid techniques. Turbulence modelling strategies for gas...

  11. The application of release models to the interpretation of rare gas coolant activities

    International Nuclear Information System (INIS)

    Wise, C.

    1985-01-01

    Much research is carried out into the release of fission products from UO 2 fuel and from failed pins. A significant application of this data is to define models of release which can be used to interpret measured coolant activities of rare gas isotopes. Such interpretation is necessary to extract operationally relevant parameters, such as the number and size of failures in the core and the 131 I that might be released during depressurization faults. The latter figure forms part of the safety case for all operating CAGRs. This paper describes and justifies the models which are used in the ANAGRAM program to interpret CAGR coolant activities, highlighting any remaining uncertainties. The various methods by which the program can extract relevant information from the measurements are outlined, and examples are given of the analysis of coolant data. These analyses point to a generally well understood picture of fission gas release from low temperature failures. Areas of higher temperature release are identified where further research would be beneficial to coolant activity analysis. (author)

  12. Multi-quantum excitation in optically pumped alkali atom: rare gas mixtures

    Science.gov (United States)

    Galbally-Kinney, K. L.; Rawlins, W. T.; Davis, S. J.

    2014-03-01

    Diode-pumped alkali laser (DPAL) technology offers a means of achieving high-energy gas laser output through optical pumping of the D-lines of Cs, Rb, and K. The exciplex effect, based on weak attractive forces between alkali atoms and polarizable rare gas atoms (Ar, Kr, Xe), provides an alternative approach via broadband excitation of exciplex precursors (XPAL). In XPAL configurations, we have observed multi-quantum excitation within the alkali manifolds which result in infrared emission lines between 1 and 4 μm. The observed excited states include the 42FJ states of both Cs and Rb, which are well above the two-photon energy of the excitation laser in each case. We have observed fluorescence from multi-quantum states for excitation wavelengths throughout the exciplex absorption bands of Cs-Ar, Cs-Kr, and Cs-Xe. The intensity scaling is roughly first-order or less in both pump power and alkali concentration, suggesting a collisional energy pooling excitation mechanism. Collisional up-pumping appears to present a parasitic loss term for optically pumped atomic systems at high intensities, however there may also be excitation of other lasing transitions at infrared wavelengths.

  13. Thermodynamic Performance Study of Biomass Gasification, Solid Oxide Fuel Cell and Micro Gas Turbine Hybrid Systems

    DEFF Research Database (Denmark)

    Bang-Møller, Christian; Rokni, Masoud

    2010-01-01

    A system level modelling study of three combined heat and power systems based on biomass gasification is presented. Product gas is converted in a micro gas turbine (MGT) in the first system, in a solid oxide fuel cell (SOFC) in the second system and in a combined SOFC–MGT arrangement in the third...

  14. The reactive solid-gas flow of a fluidized bed for UO2 conversion

    International Nuclear Information System (INIS)

    Juanico, L.E.

    1991-01-01

    The reactive solid-gas flow of a fluidized bed for UO 2 conversion was modeled. The sedimentation-reaction process was treated using the drift-flux equations. Also, the associated pressure transient due to the reaction gas release was analyzed. An experiment was carried out to compare the results, and pressure transient was numerically simulated, reaching interesting conclusions. (Author) [es

  15. Modelling of interactions between variable mass and density solid particles and swirling gas stream

    International Nuclear Information System (INIS)

    Wardach-Święcicka, I; Kardaś, D; Pozorski, J

    2011-01-01

    The aim of this work is to investigate the solid particles - gas interactions. For this purpose, numerical modelling was carried out by means of a commercial code for simulations of two-phase dispersed flows with the in-house models accounting for mass and density change of solid phase. In the studied case the particles are treated as spherical moving grains carried by a swirling stream of hot gases. Due to the heat and mass transfer between gas and solid phase, the particles are losing their mass and they are changing their volume. Numerical simulations were performed for turbulent regime, using two methods for turbulence modelling: RANS and LES.

  16. Method and system for purification of gas streams for solid oxide cells

    DEFF Research Database (Denmark)

    2011-01-01

    of: - providing at least one scrubber in the gas stream at the inlet side of the first electrode of the solid oxide cell; and/or providing at least one scrubber in the gas stream at the inlet side of the second electrode of the solid oxide cell; and - purifying the gas streams towards the first...... and second electrode; wherein the at least one scrubber in the gas stream at the inlet side of the first electrode and/or the at least one scrubber in the gas stream at the inlet side of the second electrode comprises a material suitable as an electrolyte material and a material suitable as an electrode...... material, and wherein the material suitable as an electrolyte material and a material suitable as an electrode material form triple phase boundaries similar to or identical to the triple phase boundaries of the electrode for which the gas stream is purified with the at least one scrubber....

  17. Radioactive rare gas separation using a separation cell with two kinds of membrane differing in gas permeability tendency

    International Nuclear Information System (INIS)

    Ohno, Masayoshi; Ozaki, Osamu; Sato, Hajime; Kimura, Shoji; Miyauchi, Terukatsu.

    1977-01-01

    A separation cell embodying two kinds of membrane-porous and nonporous, i.e. differing in gas permeability - has a separation factor higher than possible with a conventional separation cell with a single kind of membrane. The performance of such separation cells and of cascades constituted thereof are analyzed theoretically and measured experimentally for different conditions of operation, to determine the applicability of the concept to the separation of rare gases from gaseous waste out of nuclear plants. Theoretical considerations indicate that, in a cascade composed of symmetric separation cells, the separation performance can be improved by recycling part of the effluent from a cell back through the same cell (recycling cascade). It is shown that its performance is better than with the arrangement of diverting another effluent several stages upstream. With the recycling cascade, the symmetric separation recycling rate is determined by the depletion separation and enrichment separation factors relevant to the respective membranes. The separation performance of a 9-stage recycling cascade composed of separation cells with silicone rubber tubular membranes and cellulose acetate tubular membranes is derived for a case of Kr separation from N 2 -Kr mixture. The experimental data coincide well with the analytical results. From both the experimental and the analytical results, it is found that the attainable separation coefficient per stage of the cascade comes to average approximately 0.97. (auth.)

  18. Measurement of flow characteristics of solid particles mixed with gas in pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Siberev, S P; Nazarov, S I; Soldatkin, G I

    1983-01-01

    A mathematical model of the interaction of solid particles in a gas stream flowing through a pipeline comprises equations for the energy and material balances in the system and for force and energy interactions between the solid particles and transducers located within the pipeline. Soviet researchers confirmed that the average value of stress recorded by a transducer is proportional to the average kinetic energy of the particles; for a constant particle speed, the stress is proportional to the mass flow of the particles. The analysis and flow transducer measurements are valuable in measuring and controlling flowline sand and soil in natural gas transport from gas wells and undergound storage facilities.

  19. Electrode Kinetics and Gas Conversion in Solid Oxide Cells

    DEFF Research Database (Denmark)

    Njodzefon, Jean-Claude

    The solid oxide fuel cell (SOFC) converts hydrogen, carbon monoxide and hydrocarbon fuels (directly) into electricity with very high efficiencies and has demonstrated almost comparable performance when operated in reverse mode as a solid oxide electrolysis cell (SOEC). In this case electrical (and...... thermal) energy is stored as chemical energy of reaction products. To this end, the cells are fed with steam (H2O electrolysis), carbon dioxide (CO2 electrolysis) or a mixture of both (H2O/CO2 co-electrolysis) and of course electrical (ΔG) and thermal (TΔS) energies for the splitting of reactant compounds...... of the solid oxide cell (SOC) and independent of polarization mode (fuel cell mode or electrolysis mode), the current flowing through the cell is limited by processes such as adsorption and desorption of reactants or products, diffusion through the porous electrodes, activation or charge transfer...

  20. Adhesion of solid particles to gas bubbles. Part 2: Experimental

    NARCIS (Netherlands)

    Omota, Florin; Dimian, Alexandre C.; Bliek, A.

    2006-01-01

    In slurry bubble columns, the adhesion of solid catalyst particles to bubbles may significantly affect the G–L mass transfer and bubble size distribution. This feature may be exploited in design by modifying the hydrophilic or hydrophobic nature of the particles used. Previously we have proposed a

  1. Transport processes in exothermic gas-solid reactions

    International Nuclear Information System (INIS)

    Vijay, P.L.; Sathiyamoorthy, D.

    1997-01-01

    The variation of the concentration of gaseous reactant, temperature distribution for an exothermic reaction, the diffusivity factor and the reaction ratio profiles with various radial positions of a solid reactant have been computed and illustrated for a specific case of reduction reaction of UO 3 by hydrogen

  2. Catalytic and Gas-Solid Reactions Involving HCN over Limestone

    DEFF Research Database (Denmark)

    Jensen, Anker; Johnsson, Jan Erik; Dam-Johansen, Kim

    1997-01-01

    In coal-fired combustion systems solid calcium species may be present as ash components or limestone added to the combustion chamber. In this study heterogeneous reactions involving HCN over seven different limestones were investigated in a laboratory fixed-bed quartz reactor at 873-1,173 K...

  3. Gas-solid trickle flow hydrodynamics in a packed column

    NARCIS (Netherlands)

    Westerterp, K.R.; Kuczynski, M.

    1987-01-01

    The pressure gradient and the static and the dynamic hold-up have been measured for a system consisting of a Fluid Cracking Catalyst (FCC) of 30–150 × 10−6 m diameter, trickling over a packed bed and with a gas streaming in countercurrent flow. The experiments were carried out at ambient conditions

  4. Comparative investigation of pure and mixed rare gas atoms on coronene molecules.

    Science.gov (United States)

    Rodríguez-Cantano, Rocío; Bartolomei, Massimiliano; Hernández, Marta I; Campos-Martínez, José; González-Lezana, Tomás; Villarreal, Pablo; Pérez de Tudela, Ricardo; Pirani, Fernando; Hernández-Rojas, Javier; Bretón, José

    2017-01-21

    Clusters formed by the combination of rare gas (RG) atoms of He, Ne, Ar, and Kr on coronene have been investigated by means of a basin-hopping algorithm and path integral Monte Carlo calculations at T = 2 K. Energies and geometries have been obtained and the role played by the specific RG-RG and RG-coronene interactions on the final results is analysed in detail. Signatures of diffuse behavior of the He atoms on the surface of the coronene are in contrast with the localization of the heavier species, Ar and Kr. The observed coexistence of various geometries for Ne suggests the motion of the RG atoms on the multi-well potential energy surface landscape offered by the coronene. Therefore, the investigation of different clusters enables a comparative analysis of localized versus non-localized features. Mixed Ar-He-coronene clusters have also been considered and the competition of the RG atoms to occupy the docking sites on the molecule is discussed. All the obtained information is crucial to assess the behavior of coronene, a prototypical polycyclic aromatic hydrocarbon clustering with RG atoms at a temperature close to that of interstellar medium, which arises from the critical balance of the interactions involved.

  5. A system for removing both oxygen and nitrogen from a rare gas-hydrocarbon mixture

    International Nuclear Information System (INIS)

    Dijkman, W.H.

    1989-01-01

    A study has been made how to remove nitrogen from a mixture of a rare gas and a hydrocarbon in addition to the removal of oxygen, H 2 O and gaseous oxides. The purpose was to find a simple method for the purification of drift-chamber gases in a recirculation system. Such a method would reduce the operating costs of the large detectors presently constructed for LEP. A promising technique has been developed. First results of a chemical reactor using the novel technique are presented. The N 2 content of Ar/air mixtures containing up to 28% air could be reduced to a level of 20 ppm at a flow rate of 0.11 m 3 /h (200 ppm at 1.0 m 3 /h); and the O 2 content to 30 and 300 ppm respectively. Water and gaseous oxides concentrations were always below 5 ppm. Some of the practical problems still to be solved are discussed and suggestions are given for further development and applications. The method can in principle be of more general use. (orig.)

  6. Reduction of residual gas in a sputtering system by auxiliary sputter of rare-earth metal

    International Nuclear Information System (INIS)

    Li Dejie

    2002-01-01

    In film deposition by sputtering, the oxidation and nitrification of the sputtered material lead to degradation of film quality, particularly with respect to metal sulfide films. We propose to use auxiliary sputtering as a method to produce a fresh film of rare-earth metal, usually dysprosium (Dy), that absorbs the active gases in a sputtering system, greatly reducing the background pressure and protecting the film from oxidation and nitrification effectively. The influence of the auxiliary sputtering power consumption, sputtering time, and medium gas pressure on the background pressure in the vacuum chamber is investigated in detail. If the auxiliary sputtering power exceeds 120 W and the sputtering time is more than 4 min, the background pressure is only one fourth of the ultimate pressure pumped by an oil diffusion pump. The absorption activity of the sputtered Dy film continues at least an hour after completion of the auxiliary sputter. Applied to film deposition of Ti and ZnS, this technique has been proven to be effective. For the Ti film, the total content of N and O is reduced from 45% to 20% when the auxiliary sputtering power of Dy is 120 W, and the sputtering time is 20 min. In the case of ZnS, the content of O is reduced from 8% to 2%

  7. Quasiclassical trajectory study of the energy transfer in CO2--rare gas systems

    International Nuclear Information System (INIS)

    Suzukawa, H.H. Jr.; Wolfsberg, M.; Thompson, D.L.

    1978-01-01

    Computational methods are presented for the study of collisions between a linear, symmetric triatomic molecule and an atom by three-dimensional quasiclassical trajectory calculations. Application is made to the investigation of translational to rotational and translational to vibrational energy transfer in the systems CO 2 --Kr, CO 2 --Ar, and CO 2 --Ne. Potential-energy surfaces based on spectroscopic and molecular beam scattering data are used. In most of the calculations, the CO 2 molecule is initially in the quantum mechanical zero-point vibrational state and in a rotational state picked from a Boltzmann distribution at 300 0 K. The energy transfer processes are investigated for translational energies ranging from 0.1 to 10 eV. Translational to rotational energy transfer is found to be the major process for CO 2 --rare gas collisions at these energies. Below 1 eV there is very little translational to vibrational energy transfer. The effects of changes in the internal energy of the molecule, in the masses of the collidants, and in the potential-energy parameters are studied in an attempt to gain understanding of the energy transfer processes

  8. Experiments on state selection and Penning ionisation with fast metastable rare gas atoms

    International Nuclear Information System (INIS)

    Kroon, J.P.C.

    1985-01-01

    This thesis describes experiments with metastable He/Ne atoms. The experiments are performed in a crossed beam machine. Two different sources are used for the production of metastable atoms: a source for the production of metastable atoms in the thermal energy range and a hollow cathode arc for the production of metastable atoms in the superthermal energy range (1-7 eV). The progress made in the use of the hollow cathode arc is described as well as the experimental set-up. The rare gas energy-level diagram is characterized by two metastable levels. By optical pumping it is possible to select a single metastable level, both for He and Ne. For the case of He this is done by a recently built He quenchlamp which selectively quenches the metastable 2 1 S level population. In the thermal energy range the quenching is complete; in the superthermal energy range the 2 1 S level population is only partly quenched. For the optical pumping of Ne* atoms a cw dye laser is used. New experiments have been started on the measurement, in a crossed beam machine, of the fluorescence caused by inelastic collisions where metastable atoms are involved. The He* + Ne system is used as a pilot study for these experiments. The He-Ne laser is based on this collision system. (Auth.)

  9. Microstructure and magnetic properties of inert gas atomized rare earth permanent magnetic materials

    International Nuclear Information System (INIS)

    Sellers, C.H.; Hyde, T.A.; Branagan, D.J.; Lewis, L.H.; Panchanathan, V.

    1997-01-01

    Several permanent magnet alloys based on the ternary Nd 2 Fe 14 B (2-14-1) composition have been prepared by inert gas atomization (IGA). The microstructure and magnetic properties of these alloys have been studied as a function of particle size, both before and after heat treatment. Different particle sizes have characteristic properties due to the differences in cooling rate experienced during solidification from the melt. These properties are also strongly dependent on the alloy composition due to the cooling rate close-quote s effect on the development of the phase structure; the use of rare earth rich compositions appears necessary to compensate for a generally inadequate cooling rate. After atomization, a brief heat treatment is necessary for the development of the optimal microstructure and magnetic properties, as seen from the hysteresis loop shape and improvements in key magnetic parameters (intrinsic coercivity H ci , remanence B r , and maximum energy product BH max ). By adjusting alloy compositions specifically for this process, magnetically isotropic powders with good magnetic properties can be obtained and opportunities for the achievement of better properties appear to be possible. copyright 1997 American Institute of Physics

  10. Average energy expended per ion pair, exciton enhanced ionization (Jesse effect), electron drift velocity, average electron energy and scintillation in rare gas liquids

    International Nuclear Information System (INIS)

    Doke, T.; Hitachi, A.; Hoshi, Y.; Masuda, K.; Hamada, T.

    1977-01-01

    Precise measurements of W-values, the average energy expended per electron-hole pair in liquid Ar and Xe, were made by the electron-pulse method, and that in liquid Kr by the steady conduction current method. The results showed that the W-values were clearly smaller than those in gaseous Ar, Xe and Kr as predicted by Doke. The results can be explained by the conduction bands which exist in these rare gas liquids as well as in the solid state. The enhanced ionization yield was observed for Xe-doped liquid Ar, and it was attributed to the ionizing excitation transfer process from Ar excitons to doped Xe. This is very similar to the Jesse effect in the gas phase. The saturated value of the enhanced ionization was in good agreement with the theoretical value, and it provides strong evidence for the existence of the exciton states in liquid Ar. Fano factors in liquid Ar, Kr, Xe and Xe-doped liquid Ar have been estimated from the Fano Formula, and they were smaller than those in the gas phase. The drift velocity of electrons in liquid Ar, liquid Ar-gas mixtures and liquid Xe have been measured with gridded ionization chambers. The average electron energy in liquid Ar has been measured. The electron-induced scintillations of liquid Xe and Ar have been studied. (Kato, T.)

  11. Effects of gas periodic stimulation on key enzyme activity in gas double-dynamic solid state fermentation (GDD-SSF).

    Science.gov (United States)

    Chen, Hongzhang; Shao, Meixue; Li, Hongqiang

    2014-03-05

    The heat and mass transfer have been proved to be the important factors in air pressure pulsation for cellulase production. However, as process of enzyme secretion, the cellulase formation has not been studied in the view of microorganism metabolism and metabolic key enzyme activity under air pressure pulsation condition. Two fermentation methods in ATPase activity, cellulase productivity, weight lose rate and membrane permeability were systematically compared. Results indicated that gas double-dynamic solid state fermentation had no obviously effect on cell membrane permeability. However, the relation between ATPase activity and weight loss rate was linearly dependent with r=0.9784. Meanwhile, the results also implied that gas periodic stimulation had apparently strengthened microbial metabolism through increasing ATPase activity during gas double-dynamic solid state fermentation, resulting in motivating the production of cellulase by Trichoderma reesei YG3. Therefore, the increase of ATPase activity would be another crucial factor to strengthen fermentation process for cellulase production under gas double-dynamic solid state fermentation. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Application of lattice-gas cellular automata to the Brownian motion of solids in suspension

    International Nuclear Information System (INIS)

    Ladd, A.J.C.; Colvin, M.E.; Frenkel, D.

    1988-01-01

    An adaptation of lattice-gas cellular automata to the simulation of solid-fluid suspensions is described. The method incorporates both dissipative hydrodynamic forces and thermal fluctuations. At low solid densities, theoretical results for the drag force on a single disk and the viscosity of a suspension of disks are reproduced. The zero--shear-rate viscosity has been obtained over a range of packing fractions and results indicate that simulations of three-dimensional suspensions are feasible

  13. Rapid estimate of solid volume in large tuff cores using a gas pycnometer

    International Nuclear Information System (INIS)

    Thies, C.; Geddis, A.M.; Guzman, A.G.

    1996-09-01

    A thermally insulated, rigid-volume gas pycnometer system has been developed. The pycnometer chambers have been machined from solid PVC cylinders. Two chambers confine dry high-purity helium at different pressures. A thick-walled design ensures minimal heat exchange with the surrounding environment and a constant volume system, while expansion takes place between the chambers. The internal energy of the gas is assumed constant over the expansion. The ideal gas law is used to estimate the volume of solid material sealed in one of the chambers. Temperature is monitored continuously and incorporated into the calculation of solid volume. Temperature variation between measurements is less than 0.1 degrees C. The data are used to compute grain density for oven-dried Apache Leap tuff core samples. The measured volume of solid and the sample bulk volume are used to estimate porosity and bulk density. Intrinsic permeability was estimated from the porosity and measured pore surface area and is compared to in-situ measurements by the air permeability method. The gas pycnometer accommodates large core samples (0.25 m length x 0.11 m diameter) and can measure solid volume greater than 2.20 cm 3 with less than 1% error

  14. Rapid estimate of solid volume in large tuff cores using a gas pycnometer

    Energy Technology Data Exchange (ETDEWEB)

    Thies, C. [ed.; Geddis, A.M.; Guzman, A.G. [and others

    1996-09-01

    A thermally insulated, rigid-volume gas pycnometer system has been developed. The pycnometer chambers have been machined from solid PVC cylinders. Two chambers confine dry high-purity helium at different pressures. A thick-walled design ensures minimal heat exchange with the surrounding environment and a constant volume system, while expansion takes place between the chambers. The internal energy of the gas is assumed constant over the expansion. The ideal gas law is used to estimate the volume of solid material sealed in one of the chambers. Temperature is monitored continuously and incorporated into the calculation of solid volume. Temperature variation between measurements is less than 0.1{degrees}C. The data are used to compute grain density for oven-dried Apache Leap tuff core samples. The measured volume of solid and the sample bulk volume are used to estimate porosity and bulk density. Intrinsic permeability was estimated from the porosity and measured pore surface area and is compared to in-situ measurements by the air permeability method. The gas pycnometer accommodates large core samples (0.25 m length x 0.11 m diameter) and can measure solid volume greater than 2.20 cm{sup 3} with less than 1% error.

  15. Simulation of granular and gas-solid flows using discrete element method

    Science.gov (United States)

    Boyalakuntla, Dhanunjay S.

    2003-10-01

    In recent years there has been increased research activity in the experimental and numerical study of gas-solid flows. Flows of this type have numerous applications in the energy, pharmaceuticals, and chemicals process industries. Typical applications include pulverized coal combustion, flow and heat transfer in bubbling and circulating fluidized beds, hopper and chute flows, pneumatic transport of pharmaceutical powders and pellets, and many more. The present work addresses the study of gas-solid flows using computational fluid dynamics (CFD) techniques and discrete element simulation methods (DES) combined. Many previous studies of coupled gas-solid flows have been performed assuming the solid phase as a continuum with averaged properties and treating the gas-solid flow as constituting of interpenetrating continua. Instead, in the present work, the gas phase flow is simulated using continuum theory and the solid phase flow is simulated using DES. DES treats each solid particle individually, thus accounting for its dynamics due to particle-particle interactions, particle-wall interactions as well as fluid drag and buoyancy. The present work involves developing efficient DES methods for dense granular flow and coupling this simulation to continuum simulations of the gas phase flow. Simulations have been performed to observe pure granular behavior in vibrating beds. Benchmark cases have been simulated and the results obtained match the published literature. The dimensionless acceleration amplitude and the bed height are the parameters governing bed behavior. Various interesting behaviors such as heaping, round and cusp surface standing waves, as well as kinks, have been observed for different values of the acceleration amplitude for a given bed height. Furthermore, binary granular mixtures (granular mixtures with two particle sizes) in a vibrated bed have also been studied. Gas-solid flow simulations have been performed to study fluidized beds. Benchmark 2D

  16. Investigation of a Gas-Solid Separation Process for Cement Raw Meal

    DEFF Research Database (Denmark)

    Maarup, Claus; Hjuler, Klaus; Clement, Karsten

    2015-01-01

    The gas/solid heat exchanger (2D-HX), developed to replace the cyclone preheaters in cement plants is presented. This design aims at reducing construction height and operation costs. The separation process in the 2D-HX is experimentally investigated, and the results show that separation efficienc......The gas/solid heat exchanger (2D-HX), developed to replace the cyclone preheaters in cement plants is presented. This design aims at reducing construction height and operation costs. The separation process in the 2D-HX is experimentally investigated, and the results show that separation...

  17. Tuneable diode laser gas analyser for methane measurements on a large scale solid oxide fuel cell

    Science.gov (United States)

    Lengden, Michael; Cunningham, Robert; Johnstone, Walter

    2011-10-01

    A new in-line, real time gas analyser is described that uses tuneable diode laser spectroscopy (TDLS) for the measurement of methane in solid oxide fuel cells. The sensor has been tested on an operating solid oxide fuel cell (SOFC) in order to prove the fast response and accuracy of the technology as compared to a gas chromatograph. The advantages of using a TDLS system for process control in a large-scale, distributed power SOFC unit are described. In future work, the addition of new laser sources and wavelength modulation will allow the simultaneous measurement of methane, water vapour, carbon-dioxide and carbon-monoxide concentrations.

  18. Flow Mapping in a Gas-Solid Riser via Computer Automated Radioactive Particle Tracking (CARPT)

    Energy Technology Data Exchange (ETDEWEB)

    Muthanna Al-Dahhan; Milorad P. Dudukovic; Satish Bhusarapu; Timothy J. O' hern; Steven Trujillo; Michael R. Prairie

    2005-06-04

    Statement of the Problem: Developing and disseminating a general and experimentally validated model for turbulent multiphase fluid dynamics suitable for engineering design purposes in industrial scale applications of riser reactors and pneumatic conveying, require collecting reliable data on solids trajectories, velocities ? averaged and instantaneous, solids holdup distribution and solids fluxes in the riser as a function of operating conditions. Such data are currently not available on the same system. Multiphase Fluid Dynamics Research Consortium (MFDRC) was established to address these issues on a chosen example of circulating fluidized bed (CFB) reactor, which is widely used in petroleum and chemical industry including coal combustion. This project addresses the problem of lacking reliable data to advance CFB technology. Project Objectives: The objective of this project is to advance the understanding of the solids flow pattern and mixing in a well-developed flow region of a gas-solid riser, operated at different gas flow rates and solids loading using the state-of-the-art non-intrusive measurements. This work creates an insight and reliable database for local solids fluid-dynamic quantities in a pilot-plant scale CFB, which can then be used to validate/develop phenomenological models for the riser. This study also attempts to provide benchmark data for validation of Computational Fluid Dynamic (CFD) codes and their current closures. Technical Approach: Non-Invasive Computer Automated Radioactive Particle Tracking (CARPT) technique provides complete Eulerian solids flow field (time average velocity map and various turbulence parameters such as the Reynolds stresses, turbulent kinetic energy, and eddy diffusivities). It also gives directly the Lagrangian information of solids flow and yields the true solids residence time distribution (RTD). Another radiation based technique, Computed Tomography (CT) yields detailed time averaged local holdup profiles at

  19. Municipal Solid Waste Gasification Plant Integrated With SOFC and Gas Turbine

    DEFF Research Database (Denmark)

    Bellomare, Filippo; Rokni, Masoud

    2012-01-01

    An interesting source of producing energy with low pollutants emission and reduced environmental impact are the biomasses; particularly using Municipal Solid Waste (MSW) as fuel, can be a competitive solution not only to produce energy with negligible costs but also to decrease the storage...... in landfills. A Municipal Solid Waste Gasification Plant Integrated with Solid Oxide Fuel Cell (SOFC) and Gas Turbine (GT) has been studied and the plant is called IGSG (Integrated Gasification SOFC and GT). Gasification plant is fed by MSW to produce syngas by which the anode side of a SOFC is fed wherein...

  20. Exchange between the stagnant and flowing zone in gas-flowing solids-fixed bed contactors

    Directory of Open Access Journals (Sweden)

    ALEKSANDAR P. DUDUKOVIC

    2005-02-01

    Full Text Available In countercurrent gas – flowing solids – fixed bed contactors, a fraction of the flowing solids is in motion (dynamic holdup, while the other fraction is resting on the fixed bed elements. In this study it was experimentally proved that the stagnant zone should not be considered as a dead part of the column, but that there is a dynamic exchange between these two portions of flowing solids particles. Combining a mathematical model with tracer experiments, the rate of exchange was determined and it was shown that only a small part (ca. 20 % of the stagnant region should be considered as a dead one.

  1. Leachability of rare earth elements (REEs) from solid wastes generated during chemical processing of monazite

    International Nuclear Information System (INIS)

    Radhakrishnan, Sujata; Pillai, P.M.B.

    2001-01-01

    Studies have been carried out to assess the leachability of REEs from solid wastes generated in monazite processing. Leachability of REEs (La, Ce, Nd, Pr, Sm, Gd) and Y from PbS-Ba(Ra)SO 4 (Mixed cake) and Effluent Treatment Plant cake (calcium hydroxy apatite) has been studied using rain water as the leachant. Studies indicate that 23 -60 % of the REEs gets leached out from the mixed cake in the first 24 hours. From the ETP cake, the percentage of REEs leached out were negligible. The results provide inputs for hazards evaluation in accidental situations resulting in breach of integrity of the waste storages. (author)

  2. Modelling of non-catalytic reactors in a gas-solid trickle flow reactor: Dry, regenerative flue gas desulphurization using a silica-supported copper oxide sorbent

    NARCIS (Netherlands)

    Kiel, J.H.A.; Kiel, J.H.A.; Prins, W.; van Swaaij, Willibrordus Petrus Maria

    1992-01-01

    A one-dimensional, two-phase dispersed plug flow model has been developed to describe the steady-state performance of a relatively new type of reactor, the gas-solid trickle flow reactor (GSTFR). In this reactor, an upward-flowing gas phase is contacted with as downward-flowing dilute solids phase

  3. Development of odorous gas model using municipal solid waste emission

    International Nuclear Information System (INIS)

    Mohd Nahar bin Othman; Muhd Noor Muhd Yunus; Ku Halim Ku Hamid

    2010-01-01

    The impact of ambient odour in the vicinity of the Semenyih MSW processing plant, commonly known as RDF plant, can be very negative to the nearby population, causing public restlessness and consequently affecting the business operation and sustainability of the plant. The precise source of the odour, types, emission level and the meteorological conditions are needed to predict and established the ambient odour level at the perimeter fence of the plant and address it with respect to the ambient standards. To develop the odour gas model for the purpose of treatment is very compulsory because in MSW odour it contain many component of chemical that contribute the smell. Upon modelling using an established package as well as site measurements, the odour level at the perimeter fence of the plant was deduced and found to be marginally high, above the normal ambient level. Based on this issue, a study was made to model odour using Ausplume Model. This paper will address and discuss the measurement of ambient gas odour, the dispersion modelling to establish the critical ambient emission level, as well as experimental validation using a simulated odour. The focus will be made on exploring the use of Ausplume modelling to develop the pattern of odour concentrations for various condition and times, as well as adapting the model for MSW odour controls. (author)

  4. Validation of mechanistic models for gas precipitation in solids during postirradiation annealing experiments

    Science.gov (United States)

    Rest, J.

    1989-12-01

    A number of different phenomenological models for gas precipitation in solids during postirradiation annealing experiments have been proposed. Validation of such mechanistic models for gas release and swelling is complicated by the use of data containing large systematic errors, and phenomena characterized by synergistic effects as well as uncertainties in materials properties. Statistical regression analysis is recommended for the selection of a reasonably well characterized data base for gas release from irradiated fuel under transient heating conditions. It is demonstrated that an appropriate data selection method is required in order to realistically examine the impact of differing descriptions of the phenomena, and uncertainties in selected materials properties, on the validation results. The results of the analysis show that the kinetics of gas precipitation in solids depend on bubble overpressurization effects and need to be accounted for during the heatup phase of isothermal heating experiments. It is shown that if only the total gas release values (as opposed to time-dependent data) were available, differentiation between different gas precipitation models would be ambiguous. The observed sustained increase in the fractional release curve at relatively high temperatures after the total precipitation of intragranular gas in fission gas bubbles is ascribed to the effects of a grain-growth/grain-boundary sweeping mechanism.

  5. Validation of mechanistic models for gas precipitation in solids during postirradiation annealing experiments

    International Nuclear Information System (INIS)

    Rest, J.

    1989-01-01

    A number of different phenomenological models for gas precipitation in solids during postirradiation annealing experiments have been proposed. Validation of such mechanistic models for gas release and swelling is complicated by the use of data containing large systematic errors, and phenomena characterized by synergistic effects as well as uncertainties in materials properties. Statistical regression analysis is recommended for the selection of a reasonably well characterized data base for gas release from irradiated fuel under transient heating conditions. It is demonstrated that an appropriate data selection method is required in order to realistically examine the impact of differing descriptions of the phenomena, and uncertainties in selected materials properties, on the validation results. The results of the analysis show that the kinetics of gas precipitation in solid depend on bubble overpressurization effects and need to be accounted for during the heatup phase of isothermal heating experiments. It is shown that if only the total gas release values (as opposed to time-dependent data) were available, differentiation between different gas precipitation models would be ambiguous. The observed sustained increase in the fractional release curve at relatively high temperatures after the total precipitation of intragranular gas in fission gas bubbles is ascribed to the effects of a grain-growth/grain-boundary sweeping mechanism. (orig.)

  6. Extreme ultraviolet fluorescence spectroscopy of pure and core-shell rare gas clusters at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Schroedter, Lasse

    2013-08-15

    The interaction of rare gas clusters with short-wavelength radiation of free-electron lasers (FELs) has been studied extensively over the last decade by means of electron and ion time-of-flight spectroscopy. This thesis describes the design and construction of a fluorescence spectrometer for the extreme ultraviolet (XUV) spectral range and discusses the cluster experiments performed at FLASH, the Free-electron LAser in Hamburg. Fluorescence of xenon and of argon clusters was studied, both in dependence on the FEL pulse intensity and on the cluster size. The FEL wavelength was set to the giant 4d-resonance of xenon at 13.5 nm and the FEL pulse intensity reached peak values of 2.7.10{sup 15} W/cm{sup 2}. For xenon clusters, charge states of at least 11+ were identified. For argon, charge states up to 7+ were detected. The cluster-size dependent study revealed a decrease of the fluorescence yield per atom with increasing cluster size. This decrease is explained with the help of a geometric model. It assumes that virtually the entire fluorescence yield stems from shells of ions on the cluster surface, whereas ions in the cluster core predominantly recombine non-radiatively with electrons. However, the detailed analysis of fluorescence spectra from clusters consisting of a core of Xe atoms and a surrounding shell of argon atoms shows that, in fact, a small fraction of the fluorescence signal comes from Xe ions in the cluster core. Interestingly, these ions are as highly charged as the ions in the shells of a pure Xe cluster. This result goes beyond the current understanding of charge and energy transfer processes in these systems and points toward the observation of ultrafast charging dynamics in a time window where mass spectrometry is inherently blind. (orig.)

  7. Extreme ultraviolet fluorescence spectroscopy of pure and core-shell rare gas clusters at FLASH

    International Nuclear Information System (INIS)

    Schroedter, Lasse

    2013-08-01

    The interaction of rare gas clusters with short-wavelength radiation of free-electron lasers (FELs) has been studied extensively over the last decade by means of electron and ion time-of-flight spectroscopy. This thesis describes the design and construction of a fluorescence spectrometer for the extreme ultraviolet (XUV) spectral range and discusses the cluster experiments performed at FLASH, the Free-electron LAser in Hamburg. Fluorescence of xenon and of argon clusters was studied, both in dependence on the FEL pulse intensity and on the cluster size. The FEL wavelength was set to the giant 4d-resonance of xenon at 13.5 nm and the FEL pulse intensity reached peak values of 2.7.10 15 W/cm 2 . For xenon clusters, charge states of at least 11+ were identified. For argon, charge states up to 7+ were detected. The cluster-size dependent study revealed a decrease of the fluorescence yield per atom with increasing cluster size. This decrease is explained with the help of a geometric model. It assumes that virtually the entire fluorescence yield stems from shells of ions on the cluster surface, whereas ions in the cluster core predominantly recombine non-radiatively with electrons. However, the detailed analysis of fluorescence spectra from clusters consisting of a core of Xe atoms and a surrounding shell of argon atoms shows that, in fact, a small fraction of the fluorescence signal comes from Xe ions in the cluster core. Interestingly, these ions are as highly charged as the ions in the shells of a pure Xe cluster. This result goes beyond the current understanding of charge and energy transfer processes in these systems and points toward the observation of ultrafast charging dynamics in a time window where mass spectrometry is inherently blind. (orig.)

  8. Interactions of C+(2PJ) with rare gas atoms: incipient chemical interactions, potentials and transport coefficients

    Science.gov (United States)

    Tuttle, William D.; Thorington, Rebecca L.; Viehland, Larry A.; Breckenridge, W. H.; Wright, Timothy G.

    2018-03-01

    Accurate interatomic potentials were calculated for the interaction of a singly charged carbon cation, C+, with a single rare gas atom, RG (RG = Ne-Xe). The RCCSD(T) method and basis sets of quadruple-ζ and quintuple-ζ quality were employed; each interaction energy was counterpoise corrected and extrapolated to the basis set limit. The lowest C+(2P) electronic term of the carbon cation was considered, and the interatomic potentials calculated for the diatomic terms that arise from these: 2Π and 2Σ+. Additionally, the interatomic potentials for the respective spin-orbit levels were calculated, and the effect on the spectroscopic parameters was examined. In doing this, anomalously large spin-orbit splittings for RG = Ar-Xe were found, and this was investigated using multi-reference configuration interaction calculations. The latter indicated a small amount of RG → C+ electron transfer and this was used to rationalize the observations. This is taken as evidence of an incipient chemical interaction, which was also examined via contour plots, Birge-Sponer plots and various population analyses across the C+-RG series (RG = He-Xe), with the latter showing unexpected results. Trends in several spectroscopic parameters were examined as a function of the increasing atomic number of the RG atom. Finally, each set of RCCSD(T) potentials was employed, including spin-orbit coupling to calculate the transport coefficients for C+ in RG, and the results were compared with the limited available data. This article is part of the theme issue `Modern theoretical chemistry'.

  9. Thermodynamics analysis of the rare earth metals and their alloys with indium in solid state

    International Nuclear Information System (INIS)

    Vassiliev, V.P.; Benaissa, Ablazeze; Taldrik, A.F.

    2013-01-01

    Graphical abstract: Gibbs energies of formation vs. RE atomic numbers in REIn 3 . Highlights: •Set of experimental values was collected for REIn 3 phases. •Thermodynamic functions of formation were calculated at 298 K and 775 K. •Experimental and calculated values were compared. -- Abstract: Nonlinear correlative analyses between thermodynamic and some physico-chemical properties of rare-earth metals (RE) and their alloys with indium are performed for the isostructural phases RE and REIn 3 . The thermodynamics values (Gibbs energies of formation, enthalpies of formation, and entropies of formation at 298 K and 775 K and standard entropies) of LnIn 3 phases are calculated on the basis of calorimetry and potentiometry results. The proposed correlation between physico-chemical and thermodynamic properties agrees for all the isostructural phases REX (X are others elements of the periodic table). The resulting thermodynamic data are recommended for metallurgical handbook

  10. Variable valence of praseodymium in rare-earth oxide solid solutions

    International Nuclear Information System (INIS)

    Kravchinskaya, M.V.; Merezhinskii, K.Y.; Tikhonov, P.A.

    1986-01-01

    Solid solutions of elevated praseodymium oxide content have interesting electrical properties, making them the basis for the manufacture of high-temperature electrically conducting materials. Establishment of the composition-structure-valence state relationships enables control of the material properties. The authors performed investigations using a thermogravimetric apparatus with an electronic microbalance of type EM-5-3M, and using x-ray phase analysis of powders (DRON-1 diffractometer, CuK /SUB alpha/ -radiation). The authors also studied the kinetics of praseodymium oxidation with a thermogravimetric apparatus under isothermal conditions. Evaluation of the results with the equation of Kolmogorov, Erofeev, and Avraam indicates that the process is limited by the chemical oxidation of praseodymium and not by diffusion

  11. Predicting the Agglomeration of Cohesive Particles in a Gas-Solid Flow and its Effect on the Solids Flow

    Science.gov (United States)

    Kellogg, Kevin; Liu, Peiyuan; Lamarche, Casey; Hrenya, Christine

    2017-11-01

    In flows of cohesive particles, agglomerates will readily form and break. These agglomerates are expected to complicate how particles interact with the surrounding fluid in multiphase flows, and consequently how the solids flow. In this work, a dilute flow of particles driven by gas against gravity is studied. A continuum framework, composed of a population balance to predict the formation of agglomerates, and kinetic-theory-based balances, is used to predict the flow of particles. The closures utilized for the birth and death rates due to aggregation and breakage in the population balance take into account how the impact velocity (the granular temperature) affects the outcome of a collision as aggregation, rebound, or breakage. The agglomerate size distribution and solids velocity predicted by the continuum framework are compared to discrete element method (DEM) simulations, as well to experimental results of particles being entrained from the riser of a fluidized bed. Dow Corning Corporation.

  12. The injection of inert gas ions into solids: their trapping and escape

    International Nuclear Information System (INIS)

    Carter, G.; Armour, D.G.; Donnelly, S.E.; Ingram, D.C.; Webb, R.P.

    1980-01-01

    The first part of this contribution will review experimental studies of the trapping probabilities of ions injected into solids as a function of ion energy and indicate how the data can be modelled theoretically. It will be demonstrated that trapping is a two stage process, the first involving penetration into the solid and the second requiring atom dissolution and experimental evidence will be cited to show how the latter process may be dominant for light ions which create little radiation damage. For low ion fluences, injected atoms are generally trapped in isolation but as fluence increases gas-defect complexes are formed and it will be shown how post bombardment thermal evaluation studies can provide evidence for the growth of these complexes. Concomitant with trapping however, dissolved gas may be evolved from the solid by some form of sputtering process, sometimes by mechanisms much more efficient than congruent sputtering of the solid together with the trapped species. Measurements of the trapped atom concentration-ion fluence behaviour and of the evolution of one initially trapped species by bombardment with a second species provide information on the physical processes involved in trapped atom sputtering and upon the mechanism of gas incorporation saturation and experimental studies in this area, together with some first approximation theoretical investigations will be discussed. It will be shown that an important mechanism in dictating incorporation saturation, in addition to sputtering, is the atomic saturation of the solid by the implant. (author)

  13. Analysis of Indirect Emissions Benefits of Wind, Landfill Gas, and Municipal Solid Waste Generation

    Science.gov (United States)

    Techniques are introduced to calculate the hourly indirect emissions benefits of three types of green power resources: wind energy, municipal solid waste (MSW) combustion, and landfill gas (LFG) combustion. These techniques are applied to each of the U.S. EPA's eGRID subregions i...

  14. The constitutive distributed parameter model of multicomponent chemical processes in gas, fluid and solid phase

    International Nuclear Information System (INIS)

    Niemiec, W.

    1985-01-01

    In the literature of distributed parameter modelling of real processes is not considered the class of multicomponent chemical processes in gas, fluid and solid phase. The aim of paper is constitutive distributed parameter physicochemical model, constructed on kinetics and phenomenal analysis of multicomponent chemical processes in gas, fluid and solid phase. The mass, energy and momentum aspects of these multicomponent chemical reactions and adequate phenomena are utilized in balance operations, by conditions of: constitutive invariance for continuous media with space and time memories, reciprocity principle for isotropic and anisotropic nonhomogeneous media with space and time memories, application of definitions of following derivative and equation of continuity, to the construction of systems of partial differential constitutive state equations, in the following derivative forms for gas, fluid and solid phase. Couched in this way all physicochemical conditions of multicomponent chemical processes in gas, fluid and solid phase are new form of constitutive distributed parameter model for automatics and its systems of equations are new form of systems of partial differential constitutive state equations in sense of phenomenal distributed parameter control

  15. Numerical Simulation of Dense Gas-Solid Fluidized Beds: A Multiscale Modeling Strategy

    NARCIS (Netherlands)

    van der Hoef, Martin Anton; van Sint Annaland, M.; Deen, N.G.; Kuipers, J.A.M.

    2008-01-01

    Gas-solid fluidized beds are widely applied in many chemical processes involving physical and/or chemical transformations, and for this reason they are the subject of intense research in chemical engineering science. Over the years, researchers have developed a large number of numerical models of

  16. Numerical simulation of dense gas-solid fluidized beds : a multiscale modeling strategy

    NARCIS (Netherlands)

    Hoef, van der M.A.; Sint Annaland, van M.; Deen, N.G.; Kuipers, J.A.M.

    2008-01-01

    Gas-solid fluidized beds are widely applied in many chemical processes involving physical and/or chemical transformations, and for this reason they are the subject of intense research in chemical engineering science. Over the years, researchers have developed a large number of numerical models of

  17. Operando Spectroscopy of the Gas-Phase Aldol Condensation of Propanal over Solid Base Catalysts

    NARCIS (Netherlands)

    Hernández-giménez, Ana M.; Ruiz-martínez, Javier; Puértolas, Begoña; Pérez-ramírez, Javier; Bruijnincx, Pieter C. A.; Weckhuysen, Bert M.

    2017-01-01

    The gas-phase aldol condensation of propanal, taken as model for the aldehyde components in bio-oils, has been studied with a combined operando set-up allowing to perform FT-IR & UV–Vis diffuse reflectance spectroscopy (DRS) with on-line mass spectrometry (MS). The selected solid base catalysts, a

  18. Operation of real landfill gas fueled solid oxide fuel cell (SOFC) using internal dry reforming

    DEFF Research Database (Denmark)

    Langnickel, Hendrik; Hagen, Anke

    2017-01-01

    Biomass is one renewable energy source, which is independent from solar radiation and wind effect. Solid oxide fuel cells (SOFC’s) are able to convert landfill gas derived from landfill directly into electricity and heat with a high efficiency. In the present work a planar 16cm2 SOFC cell...... was necessary to prevent poisoning and thereby to decrease the degradation rate....

  19. Gas-solid hydroxyethylation of potato starch in a stirred vibrating fluidized bed reactor

    NARCIS (Netherlands)

    Kuipers, N.J M; Stamhuis, Eize; Beenackers, A.A C M

    A novel reactor for modifying cohesive C-powders such as in the gas-solid hydroxyethylation of semidry potato starch is characterized, the so-called stirred vibrating fluidized bed reactor. Good fluidization characteristics are obtained in this reactor for certain combinations of stirring and

  20. Set-Up and Validation of a Dynamic Solid/Gas Bioreactor

    KAUST Repository

    Lloyd-Randol, Jennifer D.

    2012-05-01

    The limited availability of fossil resourses mandates the development of new energy vectors, which is one of the Grand Challenges of the 21st Century [1]. Biocatalytic energy conversion is a promising solution to meet the increased energy demand of industrialized societies. Applications of biocatalysis in the gas-phase are so far limited to production of fine chemicals and pharmaceuticals. However, this technology has the potential for large scale biocatalytic applications [2], e.g. for the formation of novel energy carriers. The so-called solid/gas biocatalysis is defined as the application of a biocatalyst immobilized on solid-phase support acting on gaseous substrates [3]. This process combines the advantages of bio-catalysis (green chemistry, mild reaction conditions, high specicity & selectivity) and heterogeneous dynamic gas-phase processes (low diffusion limitation, high conversion, simple scale-up). This work presents the modifications of a PID Microactivity Reference reactor in order to make it suitable for solid/gas biocatalysis. The reactor design requirements are based on previously published laboratory scale solid/gas systems with a feed of saturated vapors [4]. These vapors are produced in saturation flasks, which were designed and optimized during this project. Other modifications included relocation of the gas mixing chamber, redesigning the location and heating mechanism for the reactor tube, and heating of the outlet gas line. The modified reactor system was verified based on the Candida antarctica lipase B catalyzed transesterication of ethyl acetate with 1-hexanol to hexyl acetate and ethanol and results were compared to liquid-phase model reactions. Products were analyzed on line by a gas chromatograph with a flame ionization detector. C. antarc- tica physisorbed on silica particles produced a 50% conversion of hexanol at 40 C in the gas-phase. A commercial immobilized lipase from Iris Biotech produced 99% and 97% conversions of hexanol in

  1. Contribution to the modelling of gas-solid reactions and reactors

    International Nuclear Information System (INIS)

    Patisson, F.

    2005-09-01

    Gas-solid reactions control a great number of major industrial processes involving matter transformation. This dissertation aims at showing that mathematical modelling is a useful tool for both understanding phenomena and optimising processes. First, the physical processes associated with a gas-solid reaction are presented in detail for a single particle, together with the corresponding available kinetic grain models. A second part is devoted to the modelling of multiparticle reactors. Different approaches, notably for coupling grain models and reactor models, are illustrated through various case studies: coal pyrolysis in a rotary kiln, production of uranium tetrafluoride in a moving bed furnace, on-grate incineration of municipal solid wastes, thermogravimetric apparatus, nuclear fuel making, steel-making electric arc furnace. (author)

  2. Online gas composition estimation in solid oxide fuel cell systems with anode off-gas recycle configuration

    Science.gov (United States)

    Dolenc, B.; Vrečko, D.; Juričić, Ð.; Pohjoranta, A.; Pianese, C.

    2017-03-01

    Degradation and poisoning of solid oxide fuel cell (SOFC) stacks are continuously shortening the lifespan of SOFC systems. Poisoning mechanisms, such as carbon deposition, form a coating layer, hence rapidly decreasing the efficiency of the fuel cells. Gas composition of inlet gases is known to have great impact on the rate of coke formation. Therefore, monitoring of these variables can be of great benefit for overall management of SOFCs. Although measuring the gas composition of the gas stream is feasible, it is too costly for commercial applications. This paper proposes three distinct approaches for the design of gas composition estimators of an SOFC system in anode off-gas recycle configuration which are (i.) accurate, and (ii.) easy to implement on a programmable logic controller. Firstly, a classical approach is briefly revisited and problems related to implementation complexity are discussed. Secondly, the model is simplified and adapted for easy implementation. Further, an alternative data-driven approach for gas composition estimation is developed. Finally, a hybrid estimator employing experimental data and 1st-principles is proposed. Despite the structural simplicity of the estimators, the experimental validation shows a high precision for all of the approaches. Experimental validation is performed on a 10 kW SOFC system.

  3. Angular distributions of low kinetic energy photoelectrons in one- and two-photon ionisation of rare gas atoms

    International Nuclear Information System (INIS)

    O'Keeffe, P; Bolognesi, P; Avaldi, L; Richter, R; Moise, A; Cleva, P De; Mihelic, A

    2012-01-01

    The angular distributions of electrons emitted in the photoionisation of rare gas atoms using one and two photons are presented. The one-photon results show that these differential measurements can provide complementary information on the photoionisation event with respect to the measurement of the total absorption cross section while the two photon ionization allows additional parameters to be extracted from the experiments thus permitting a more complete description of the photoionisation dynamics.

  4. Hydrodynamic boundary conditions for one-component liquid-gas flows on non-isothermal solid substrates

    KAUST Repository

    Xu, Xinpeng; Liu, Chun; Qian, Tiezheng

    2012-01-01

    profiles of liquid-gas flows on non-isothermal, heterogeneous solid substrates is still absent. The purpose of this work is to construct a continuum model for simulating the liquid-gas flows on solid surfaces that are flat and rigid, and may involve

  5. The rare earth elements in municipal solid waste incinerators ash and promising tools for their prospecting

    Energy Technology Data Exchange (ETDEWEB)

    Funari, Valerio, E-mail: valerio.funari@unibo.it [Dipartimento di Scienze Biologiche, Geologiche e Ambientali (BiGeA)—University of Bologna, Piazza di Porta San Donato 1, Bologna (Italy); Bokhari, Syed Nadeem Hussain [General and Analytical Chemistry—Montanuniversität Leoben, Franz-Josef-Str. 18, Leoben (Austria); Vigliotti, Luigi [Istituto di Scienze Marine (ISMAR-CNR)—National Research Council, Via Piero Gobetti 101, Bologna (Italy); Meisel, Thomas [General and Analytical Chemistry—Montanuniversität Leoben, Franz-Josef-Str. 18, Leoben (Austria); Braga, Roberto [Dipartimento di Scienze Biologiche, Geologiche e Ambientali (BiGeA)—University of Bologna, Piazza di Porta San Donato 1, Bologna (Italy)

    2016-01-15

    Highlights: • The REE concentrations of bottom and fly ashes from municipal incinerators are investigated. • First attempt toward discriminating the magnetic signature (susceptibility) of ashes from incinerators. • New methods and parameters for REE prospecting, which can be determined quickly and with limited costs, are provided. - Abstract: Bottom and fly ashes from Municipal Solid Waste Incinerators (MSWI) are hazardous products that present concern for their safe management. An attractive option to reduce their impact both on the environment and the financial commitment is turning MSWI ashes into secondary raw materials. In this study we present the REE content and distribution of bottom and fly ashes from MSWI after a highly effective digestion method and samples analysis by ICP–MS. The chondrite-normalised REE patterns of MSWI bottom and fly ash are comparable with that of crustal averages, suggesting a main geogenic source. Deviations from typical crustal pattern (e.g., Eu, Tb) disclose a contribution of likely anthropogenic provenance. The correlation with major elements indicates possible sources for REE and facilitates a preliminary resource assessment. Moreover, magnetic susceptibility measurements can be a useful prospecting method in urban ores made of MSWI ashes. The relationship between REE and some influencing parameters (e.g., Pricing Influence Factor) emphasises the importance of MSWI ash as alternative source of REE and the need of further efforts for REE recovery and purification from low concentrations but high flows waste.

  6. A nanostructured surface increases friction exponentially at the solid-gas interface

    Science.gov (United States)

    Phani, Arindam; Putkaradze, Vakhtang; Hawk, John E.; Prashanthi, Kovur; Thundat, Thomas

    2016-09-01

    According to Stokes’ law, a moving solid surface experiences viscous drag that is linearly related to its velocity and the viscosity of the medium. The viscous interactions result in dissipation that is known to scale as the square root of the kinematic viscosity times the density of the gas. We observed that when an oscillating surface is modified with nanostructures, the experimentally measured dissipation shows an exponential dependence on kinematic viscosity. The surface nanostructures alter solid-gas interplay greatly, amplifying the dissipation response exponentially for even minute variations in viscosity. Nanostructured resonator thus allows discrimination of otherwise narrow range of gaseous viscosity making dissipation an ideal parameter for analysis of a gaseous media. We attribute the observed exponential enhancement to the stochastic nature of interactions of many coupled nanostructures with the gas media.

  7. A nanostructured surface increases friction exponentially at the solid-gas interface.

    Science.gov (United States)

    Phani, Arindam; Putkaradze, Vakhtang; Hawk, John E; Prashanthi, Kovur; Thundat, Thomas

    2016-09-06

    According to Stokes' law, a moving solid surface experiences viscous drag that is linearly related to its velocity and the viscosity of the medium. The viscous interactions result in dissipation that is known to scale as the square root of the kinematic viscosity times the density of the gas. We observed that when an oscillating surface is modified with nanostructures, the experimentally measured dissipation shows an exponential dependence on kinematic viscosity. The surface nanostructures alter solid-gas interplay greatly, amplifying the dissipation response exponentially for even minute variations in viscosity. Nanostructured resonator thus allows discrimination of otherwise narrow range of gaseous viscosity making dissipation an ideal parameter for analysis of a gaseous media. We attribute the observed exponential enhancement to the stochastic nature of interactions of many coupled nanostructures with the gas media.

  8. DEM-CFD simulation of purge gas flow in a solid breeder pebble bed

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hao [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230027 (China); Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Li, Zhenghong [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); University of Science and Technology of China, Hefei 230027 (China); Guo, Haibing [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Ye, Minyou [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230027 (China); Huang, Hongwen, E-mail: inpclane@sina.com [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China)

    2016-12-15

    Solid tritium breeding blanket applying pebble bed concept is promising for fusion reactors. Tritium bred in the pebble bed is purged out by inert gas. The flow characteristics of the purge gas are important for the tritium transport from the solid breeder materials. In this study, a randomly packed pebble bed was generated by Discrete Element Method (DEM) and verified by radial porosity distribution. The flow parameters of the purge gas in channels were solved by Computational Fluid Dynamics (CFD) method. The results show that the normalized velocity magnitudes have the same damped oscillating patterns with radial porosity distribution. Besides, the bypass flow near the wall cannot be ignored in this model, and it has a slight increase with inlet velocity. Furthermore, higher purging efficiency becomes with higher inlet velocity and especially higher in near wall region.

  9. GRANULATION AND BRIQUETTING OF SOLID PRODUCTS FROM FLUE GAS DESULFURIZATION

    Directory of Open Access Journals (Sweden)

    Jan J. Hycnar

    2015-11-01

    Full Text Available Most flue gas desulfurization products can be characterized by significant solubility in water and dusting in dry state. These characteristics can cause a considerable pollution of air, water, and soil. Among many approaches to utilization of this waste, the process of agglomeration using granulation or briquetting has proved very effective. Using desulfurization products a new material of aggregate characteristics has been acquired, and this material is resistant to water and wind erosion as well as to the conditions of transportation and storage. The paper presents the results of industrial trials granulation and briquetting of calcium desulphurization products. The granulation of a mixture of phosphogypsum used with fly ash (in the share 1:5. The resulting granules characterized by a compressive strength of 41.6 MPa, the damping resistance of 70% and 14.2% abrasion. The granulate was used for the production of cement mix. The produced concrete mortar have a longer setting and hardening time, as compared to the traditional ash and gypsum mortar, and have a higher or comparable flexural and compressive strength during hardening. Briquetting trials made of a product called synthetic gypsum or rea-gypsum both in pure form and with the addition of 5% and 10% of the limestone dust. Briquettes have a high initial strength and resistance to abrasion. The values ​​of these parameters increased after 72 hours of seasoning. It was found that higher hardiness of briquettes with rea-gypsum was obtained with the impact of atmospheric conditions and higher resistance to elution of water-soluble components in comparison to ash briquettes.

  10. Ternary and quaternary solid solutions in rare earth alloy phases with the CaCu5-type structure

    International Nuclear Information System (INIS)

    Malani, G.K.; Raman, A.; Mohanty, R.C.

    1992-01-01

    Crystal structural data were analyzed in seleced CaCu 5 -type ternary and quaternary solid solutions to assess the crystal chemical characteristics and stability features of the CaCu 5 -type structure in rare earth containing alloy phases. LaNi 5 was found to dissolve 100 mol% LaCu 5 , 100 mol% ErNi 5 , about 50 mol% LaIr 5 , 40 mol% 'LaMn 5 ', 20 mol% 'LaFe 5 ', and 25 mol% ErRh 5 . In contrast, LaCo 5 did not dissolve any Mn or any of the other elements other than Al - it dissolved about 20 mol% 'LaAl 5 '. LaCu 5 behaves similar to LaNi 5 in solid solutions. From the lack of solubility of any other element in LaFe 5 , LaCo 5 , LaRh 5 , and LaIr 5 and their great instability, these are inferred to be borderline cases in the realm of the CaCu 5 -type structure. In the CaCu 5 and related crystal structures, Ir is compatible with Ni, but not with Co or Rh, and Rh is not compatible with either Ni or Ir. (orig.) [de

  11. Dynamics for CH3F and CD3F isolated in rare gas solids

    International Nuclear Information System (INIS)

    Jones, L.H.; Swanson, B.I.

    1982-01-01

    High resolution infrared spectra have been obtained for CH 3 F and CD 3 F in argon and krypton matrices from 3 to 39 K. Low-temperature spectra show structure indicative of two stable monomer sites. As temperature is raised, the structure collapses to give symmetric peaks for each mode. The line shapes and their broadening with temperature show large dependence on the modes, isotope, and host matrix. On the basis of the absence of rovibrational structure and the very different line shapes for the various modes, we conclude that free or hindered rotation does not contribute to the absorption lines of methyl fluoride in argon or krypton matrices below 40 K. The mode dependent line broadening with increasing temperatures has been attributed to vibrational dephasing involving low energy site local phonon modes. Implications with regard to vibrational energy relaxation, which is currently thought to be dominated by a vibration to rotation energy transfer, are discussed

  12. Orientational ordering and site structure of SiF4 trapped in rare gas solids

    Science.gov (United States)

    Jones, Llewellyn H.; Swanson, Basil I.; Ekberg, Scott A.

    1984-12-01

    The infrared spectrum of the ν3 mode of SiF4 shows only one site with marked site-symmetry splitting accompanied by pronounced (>95%) orientational ordering. The results indicate a site symmetry of C3v with the SiF4 molecule occupying a four-atom substitutional site with a cubic-close-packed environment. In krypton and xenon matrices, however, SiF4 occupies a three-atom substitutional site. The fact that SiF4 shows only one dominant site when present in argon matrices of UF6 indicates that one of the two UF6 sites has a local hexagonal close packed environment induced by short range stacking faults.

  13. Nanotubes of rare earth cobalt oxides for cathodes of intermediate-temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Sacanell, Joaquin [Departamento de Fisica, Centro Atomico Constituyentes, CNEA, Av. Gral. Paz 1499, 1650 San Martin, Buenos Aires (Argentina); CINSO (Centro de Investigaciones en Solidos), CITEFA-CONICET, J.B. de La Salle 4397, 1603 Villa Martelli, Buenos Aires (Argentina); Leyva, A. Gabriela [Departamento de Fisica, Centro Atomico Constituyentes, CNEA, Av. Gral. Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, UNSAM. Av. Gral. Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Bellino, Martin G.; Lamas, Diego G. [CINSO (Centro de Investigaciones en Solidos), CITEFA-CONICET, J.B. de La Salle 4397, 1603 Villa Martelli, Buenos Aires (Argentina)

    2010-04-02

    In this work we studied the electrochemical properties of cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs) prepared with nanotubes of La{sub 0.6}Sr{sub 0.4}CoO{sub 3} (LSCO). Their nanostructures consist of agglomerated nanoparticles in tubular structures of sub-micrometric diameter. The resulting cathodes are highly porous both at the micro- and the nanoscale. This fact increases significantly the access to active sites for the oxygen reduction. We investigated the influence of the diameter of the precursor nanotubes on the polarization resistance of the LSCO cathodes on CeO{sub 2}-10 mol.% Sm{sub 2}O{sub 3} (SDC) electrolytes under air atmosphere, evaluated in symmetrical [LSCO/SDC/LSCO] cells. Our results indicate an optimized performance when the diameter of precursor nanotubes is sufficiently small to become dense nanorods after cathode sintering. We present a phenomenological model that successfully explains the behavior observed and considers that a small starting diameter acts as a barrier that prevents grains growth. This is directly related with the lack of contact points between nanotubes in the precursor, which are the only path for the growth of ceramic grains. We also observed that a conventional sintering process (of 1 h at 1000 C with heating and cooling rates of 10 C min{sup -1}) has to be preferred against a fast firing one (1 or 2 min at 1100 C with heating and cooling rates of 100 C min{sup -1}) in order to reach a higher performance. However, a good adhesion of the cathode can be achieved with both methods. Our results suggest that oxygen vacancy diffusion is enhanced while decreasing LSCO particle size. This indicates that the high performance of our nanostructured cathodes is not only related with the increase of the number of active sites for oxygen reduction but also to the fact that the nanotubes are formed by nanoparticles. (author)

  14. Separation of rare earth mixtures by gas chromatography using dipivaloylmethane as complexing agent

    International Nuclear Information System (INIS)

    Golubtsova, V.Yu.; Luchinkin, V.V.; Martynenko, L.I.; Murav'eva, I.A.; Sokolov, D.N.

    1981-01-01

    Possibility of using dipivaloylmethave for quantitative separation of rare earth element mixtures under the regime of chromatography for preparative and analytical purposes, is studied. Introduction of β-diketone surplus into the chromatographic solution is shown to remove the necessity of column conditioning. It is stated that chelate solution should have concentration above the threshold one. The developed method is applicable for quantitative separation of some rare earth mixtures for preparative purposes, as well as for the analysis of rare earth mixtures, containing components in equivalent quantities [ru

  15. Experimental investigation of attrition resistance of zeolite catalysts in two particle gas-solid-solid fluidization system

    International Nuclear Information System (INIS)

    Nawaz, Z.; Ziaoping, T.; Shu, Q.; Wei, F.; Naveed, S.

    2010-01-01

    In the study of mechanical degradation of 34 ZSM-5 and SAPO catalysts, using the gas jet attrition - ASTM standard fluidized bed test (D-5757), the effect of particle size and its quantitative analysis in co-fluidization environment was investigated on the air jet index (AJI) basis. In gas-solid-solid fluidized bed reactors (GSS-FBR), two different sized particles were fluidized under isothermal conditions. In case of ZSM-5 and SAPO-34, significant attrition resistance was observed, which was attributed to small pore size and specific structural strength of the mobile framework image (MFI) and chabasite (CHA) structures, respectively. The optimum AJI for SAPO-34 and ZSM-5 (of particle size 0.2 mm) in GSS-fluidization system was observed to be 0.0118 and 0.0062, respectively. In co-fluidization, deviations from Gwyn relationship were observed due to change in impact of collision. Therefore, zeolites are recommended as suitable catalysts or catalytic supports (for doping of expensive metals) and for commercial use in GSS-FBR. (author)

  16. Amperometric detector for gas chromatography based on a silica sol-gel solid electrolyte.

    Science.gov (United States)

    Steinecker, William H; Miecznikowski, Krzysztof; Kulesza, Pawel J; Sandlin, Zechariah D; Cox, James A

    2017-11-01

    An electrochemical cell comprising a silica sol-gel solid electrolyte, a working electrode that protrudes into a gas phase, and reference and counter electrodes that contact the solid electrolyte comprises an amperometric detector for gas chromatography. Under potentiostatic conditions, a current related to the concentration of an analyte in the gas phase is produced by its oxidation at the three-phase boundary among the sol-gel, working electrode, and the gas phase. The sol-gel is processed to contain an electrolyte that also serves as a humidistat to maintain a constant water activity even in the presence the gas chromatographic mobile phase. Response was demonstrated toward a diverse set of analytes, namely hydrogen, 1,2-ethandithiol, phenol, p-cresol, and thioanisole. Using flow injection amperometry of hydrogen with He as the carrier gas, 90% of the steady-state current was achieved in < 1s at a flow rate of 20mLmin -1 . A separation of 1,2-ethandithiol, phenol, p-cresol, and thioanisole at a 2.2mLmin -1 flow rate was achieved with respective detection limits (k = 3 criterion) of 4, 1, 3, and 70 ppmv when the working electrode potential was 800mV. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Greenhouse gas emissions from solid waste in Beijing: The rising trend and the mitigation effects by management improvements.

    Science.gov (United States)

    Yu, Yongqiang; Zhang, Wen

    2016-04-01

    Disposal of solid waste poses great challenges to city managements. Changes in solid waste composition and disposal methods, along with urbanisation, can certainly affect greenhouse gas emissions from municipal solid waste. In this study, we analysed the changes in the generation, composition and management of municipal solid waste in Beijing. The changes of greenhouse gas emissions from municipal solid waste management were thereafter calculated. The impacts of municipal solid waste management improvements on greenhouse gas emissions and the mitigation effects of treatment techniques of greenhouse gas were also analysed. Municipal solid waste generation in Beijing has increased, and food waste has constituted the most substantial component of municipal solid waste over the past decade. Since the first half of 1950s, greenhouse gas emission has increased from 6 CO2-eq Gg y(-1)to approximately 200 CO2-eq Gg y(-1)in the early 1990s and 2145 CO2-eq Gg y(-1)in 2013. Landfill gas flaring, landfill gas utilisation and energy recovery in incineration are three techniques of the after-emission treatments in municipal solid waste management. The scenario analysis showed that three techniques might reduce greenhouse gas emissions by 22.7%, 4.5% and 9.8%, respectively. In the future, if waste disposal can achieve a ratio of 4:3:3 by landfill, composting and incineration with the proposed after-emission treatments, as stipulated by the Beijing Municipal Waste Management Act, greenhouse gas emissions from municipal solid waste will decrease by 41%. © The Author(s) 2016.

  18. Assessment of alternative disposal methods to reduce greenhouse gas emissions from municipal solid waste in India.

    Science.gov (United States)

    Yedla, Sudhakar; Sindhu, N T

    2016-06-01

    Open dumping, the most commonly practiced method of solid waste disposal in Indian cities, creates serious environment and economic challenges, and also contributes significantly to greenhouse gas emissions. The present article attempts to analyse and identify economically effective ways to reduce greenhouse gas emissions from municipal solid waste. The article looks at the selection of appropriate methods for the control of methane emissions. Multivariate functional models are presented, based on theoretical considerations as well as the field measurements to forecast the greenhouse gas mitigation potential for all the methodologies under consideration. Economic feasibility is tested by calculating the unit cost of waste disposal for the respective disposal process. The purpose-built landfill system proposed by Yedla and Parikh has shown promise in controlling greenhouse gas and saving land. However, these studies show that aerobic composting offers the optimal method, both in terms of controlling greenhouse gas emissions and reducing costs, mainly by requiring less land than other methods. © The Author(s) 2016.

  19. Numerical simulation of gas-solid flow in an interconnected fluidized bed

    Directory of Open Access Journals (Sweden)

    Canneto Giuseppe

    2015-01-01

    Full Text Available The gas-particles flow in an interconnected bubbling fluidized cold model is simulated using a commercial CFD package by Ansys. Conservation equations of mass and momentum are solved using the Eulerian granular multiphase model. Bubbles formation and their paths are analyzed to investigate the behaviour of the bed at different gas velocities. Experimental tests, carried out by the cold model, are compared with simulation runs to study the fluidization quality and to estimate the circulation of solid particles in the bed.

  20. Integration of A Solid Oxide Fuel Cell into A 10 MW Gas Turbine Power Plant

    Directory of Open Access Journals (Sweden)

    Denver F. Cheddie

    2010-04-01

    Full Text Available Power generation using gas turbine power plants operating on the Brayton cycle suffers from low efficiencies. In this work, a solid oxide fuel cell (SOFC is proposed for integration into a 10 MW gas turbine power plant, operating at 30% efficiency. The SOFC system utilizes four heat exchangers for heat recovery from both the turbine outlet and the fuel cell outlet to ensure a sufficiently high SOFC temperature. The power output of the hybrid plant is 37 MW at 66.2% efficiency. A thermo-economic model predicts a payback period of less than four years, based on future projected SOFC cost estimates.

  1. Analysis of Gas Leakage and Current Loss of Solid Oxide Fuel Cells by Screen Printing

    DEFF Research Database (Denmark)

    Jia, Chuan; Han, Minfang; Chen, Ming

    2017-01-01

    Two types of anode supported solid oxide fuel cell (SOFC) NiO-YSZ/YSZ/GDC/LSCF with the same structure and different manufacturing process were tested. Gas leakage was suspected for cells manufactured with screen printing technique. Effective leak current densities for both types of cells were...... calculated. Their performances of electrochemical impedance spectroscopy (EIS) were compared and distribution function of relaxation times (DRT) technique was also used to find the clue of gas leakage. Finally, thinning and penetrating holes were observed in electrolyte layer, which confirmed the occurrence...

  2. Solar-wind krypton and solid/gas fractionation in the early solar nebula

    Science.gov (United States)

    Wiens, Roger C.; Burnett, D. S.; Neugebauer, M.; Pepin, R. O.

    1991-01-01

    The solar-system Kr abundance is calculated from solar-wind noble-gas ratios, determined previously by low-temperature oxidations of lunar ilmenite grains, normalized to Si by spacecraft solar-wind measurements. The estimated Kr-83 abundance of 4.1 + or - 1.5 per million Si atoms is within uncertainty of estimates assuming no fractionation, determined from CI-chondrite abundances of surrounding elements. This is significant because it is the first such constraint on solid/gas fractionation, though the large uncertainty only confines it to somewhat less than a factor of two.

  3. Influence of additives and impurities in sweep gas and solid tritium release behaviour from lithium ceramics (review)

    International Nuclear Information System (INIS)

    Tanaka, Satoru

    1991-01-01

    Tritium release from solid breeding material is affected by small amounts of additives or impurities in the sweep gas or solid itself. Addition of hydrogen or water vapor to the sweep gas is reported to enhance the surface reaction of tritium release. Doping to solid breeder with elements of different valence from lithium has a possibility to improve tritium diffusion in the solid. Surface reaction and migration behavior in bulk are believed to be also affected by impurities in the sweep gas and in the solid. In order to model tritium release behavior in the blanket of fusion reactor, the mechanism of interaction with these additives or impurities must be quantitatively formulated. However, the mechanism of these remains to be elucidated. In this paper effects of these additives and impurities on tritium migration are reviewed. The mechanism of surface reaction for He+H 2 sweep gas is also discussed. (orig.)

  4. Comparison Between Conventional Design and Cathode Gas Recirculation Design of a Direct-Syngas Solid Oxide Fuel Cell–Gas Turbine Hybrid Systems Part I: Design Performance

    Directory of Open Access Journals (Sweden)

    Vahid Azami

    2017-06-01

    Keywords: Solid oxide fuel cell, Gas turbine, Cathode gas recirculation, Exergy. Article History: Received Feb 23rd 2017; Received in revised form May 26th 2017; Accepted June 1st 2017; Available online How to Cite This Article: Azami, V, and Yari, M. (2017 Comparison between conventional design and cathode gas recirculation design of a direct-syngas solid oxide fuel cell–gas turbine hybrid systems part I: Design performance. International Journal of Renewable Energy Develeopment, 6(2, 127-136. https://doi.org/10.14710/ijred.6.2.127-136

  5. A light-gas gun for acceleration of pellets of solid D2

    International Nuclear Information System (INIS)

    Nordskov, A.; Skovgaard, H.; Soerensen, H.; Weisberg, K.V.

    1980-10-01

    A gun has been designed and built to be used for injecting solid D 2 pellets into a small tokamak for pellet-plasma interaction studies. The pellets are formed and accelerated at temperatures close to those of liquid helium. They are propelled with pressurised H 2 -gas; the pressure arises when a quantity of solid H 2 placed in the gun barrel behind the pellet is pulse heated. Pellet velocities up to 240 m/s have been obtained. The directional accuracy is better than 0.2deg and the repetition rate is one firing every five minutes. The pellet volume is 0.6 mm 3 (2 x 10 19 molecules) while the quantity of propeller gas used is around 12 x 10 19 molecules. (author)

  6. Solid-State Gas Sensors: Sensor System Challenges in the Civil Security Domain

    Directory of Open Access Journals (Sweden)

    Gerhard Müller

    2016-01-01

    Full Text Available The detection of military high explosives and illicit drugs presents problems of paramount importance in the fields of counter terrorism and criminal investigation. Effectively dealing with such threats requires hand-portable, mobile and affordable instruments. The paper shows that solid-state gas sensors can contribute to the development of such instruments provided the sensors are incorporated into integrated sensor systems, which acquire the target substances in the form of particle residue from suspect objects and which process the collected residue through a sequence of particle sampling, solid-vapor conversion, vapor detection and signal treatment steps. Considering sensor systems with metal oxide gas sensors at the backend, it is demonstrated that significant gains in sensitivity, selectivity and speed of response can be attained when the threat substances are sampled in particle as opposed to vapor form.

  7. Solid-State Gas Sensors: Sensor System Challenges in the Civil Security Domain.

    Science.gov (United States)

    Müller, Gerhard; Hackner, Angelika; Beer, Sebastian; Göbel, Johann

    2016-01-20

    The detection of military high explosives and illicit drugs presents problems of paramount importance in the fields of counter terrorism and criminal investigation. Effectively dealing with such threats requires hand-portable, mobile and affordable instruments. The paper shows that solid-state gas sensors can contribute to the development of such instruments provided the sensors are incorporated into integrated sensor systems, which acquire the target substances in the form of particle residue from suspect objects and which process the collected residue through a sequence of particle sampling, solid-vapor conversion, vapor detection and signal treatment steps. Considering sensor systems with metal oxide gas sensors at the backend, it is demonstrated that significant gains in sensitivity, selectivity and speed of response can be attained when the threat substances are sampled in particle as opposed to vapor form.

  8. Gas production in anaerobic dark-fermentation processes from agriculture solid waste

    Science.gov (United States)

    Sriwuryandari, L.; Priantoro, E. A.; Sintawardani, N.

    2017-03-01

    Approximately, Bandung produces agricultural solid waste of 1549 ton/day. This wastes consist of wet-organic matter and can be used for bio-gas production. The research aimed to apply the available agricultural solid waste for bio-hydrogen. Biogas production was done by a serial of batches anaerobic fermentation using mix-culture bacteria as the active microorganism. Fermentation was carried out inside a 30 L bioreactor at room temperature. The analyzed parameters were of pH, total gas, temperature, and COD. Result showed that from 3 kg/day of organic wastes, various total gases of O2, CH4, H2, CO2, and CnHn,O2 was produced.

  9. Thermodynamic simulation of biomass gas steam reforming for a solid oxide fuel cell (SOFC system

    Directory of Open Access Journals (Sweden)

    A. Sordi

    2009-12-01

    Full Text Available This paper presents a methodology to simulate a small-scale fuel cell system for power generation using biomass gas as fuel. The methodology encompasses the thermodynamic and electrochemical aspects of a solid oxide fuel cell (SOFC, as well as solves the problem of chemical equilibrium in complex systems. In this case the complex system is the internal reforming of biomass gas to produce hydrogen. The fuel cell input variables are: operational voltage, cell power output, composition of the biomass gas reforming, thermodynamic efficiency, electrochemical efficiency, practical efficiency, the First and Second law efficiencies for the whole system. The chemical compositions, molar flows and temperatures are presented to each point of the system as well as the exergetic efficiency. For a molar water/carbon ratio of 2, the thermodynamic simulation of the biomass gas reforming indicates the maximum hydrogen production at a temperature of 1070 K, which can vary as a function of the biomass gas composition. The comparison with the efficiency of simple gas turbine cycle and regenerative gas turbine cycle shows the superiority of SOFC for the considered electrical power range.

  10. Simulations of small solid accretion on to planetesimals in the presence of gas

    Science.gov (United States)

    Hughes, A. G.; Boley, A. C.

    2017-12-01

    The growth and migration of planetesimals in a young protoplanetary disc are fundamental to planet formation. In all models of early growth, there are several processes that can inhibit grains from reaching larger sizes. Nevertheless, observations suggest that growth of planetesimals must be rapid. If a small number of 100 km sized planetesimals do manage to form in the disc, then gas drag effects could enable them to efficiently accrete small solids from beyond their gravitationally focused cross-section. This gas-drag-enhanced accretion can allow planetesimals to grow at rapid rates, in principle. We present self-consistent hydrodynamics simulations with direct particle integration and gas-drag coupling to estimate the rate of planetesimal growth due to pebble accretion. Wind tunnel simulations are used to explore a range of particle sizes and disc conditions. We also explore analytic estimates of planetesimal growth and numerically integrate planetesimal drift due to the accretion of small solids. Our results show that, for almost every case that we consider, there is a clearly preferred particle size for accretion that depends on the properties of the accreting planetesimal and the local disc conditions. For solids much smaller than the preferred particle size, accretion rates are significantly reduced as the particles are entrained in the gas and flow around the planetesimal. Solids much larger than the preferred size accrete at rates consistent with gravitational focusing. Our analytic estimates for pebble accretion highlight the time-scales that are needed for the growth of large objects under different disc conditions and initial planetesimal sizes.

  11. Structure dynamics. Determination of the coupled relationships in solid-fluid-gas dynamics

    International Nuclear Information System (INIS)

    Hofmann, H.; Huber, A.; Naehring, T.; Bonakdarzadeh, S.; Faass, E.; Gaschen, J.P.; Kniffka, K.; Pilz, H.

    1980-06-01

    In the present paper the code concept SAN (Structure ANalysis) is presented. SAN is designed according to the modular principle using describing and coordinating modules. SAN is based on the discreetizing method. It uses compatible forms of description. The method of finite elements is applied. Solid-fluid-gas structures may be described as well as their interrelations in the linear and nonlinear region, including phase transitions with the associated descriptions of material and state. (orig./RW) [de

  12. Prototype demonstration of dual sorbent injection for acid gas control on municipal solid waste combustion units

    Energy Technology Data Exchange (ETDEWEB)

    None

    1994-05-01

    This report gathered and evaluated emissions and operations data associated with furnace injection of dry hydrated lime and duct injection of dry sodium bicarbonate at a commercial, 1500 ton per day, waste-to-energy facility. The information compiled during the project sheds light on these sorbents to affect acid gas emissions from municipal solid waste combustors. The information assesses the capability of these systems to meet the 1990 Clean Air Act and 1991 EPA Emission Guidelines.

  13. A pyrolysis/gas chromatographic method for the determination of hydrogen in solid samples

    Science.gov (United States)

    Carr, R. H.; Bustin, R.; Gibson, E. K.

    1987-01-01

    A method is described for the determination of hydrogen in solid samples. The sample is heated under vacuum after which the evolved gases are separated by gas chromatography with a helium ionization detector. The system is calibrated by injecting known amounts of hydrogen, as determined manometrically. The method, which is rapid and reliable, was checked for a variety of lunar soils; the limit of detection is about 10 ng of hydrogen.

  14. Measurement of Gas Velocities in the Presence of Solids in the Riser of a Cold Flow Circulating Fluidized Bed

    International Nuclear Information System (INIS)

    Spenik, J.; Ludlow, J.C.; Compston, R.; Breault, R.W.

    2007-01-01

    The local gas velocity and the intensity of the gas turbulence in a gas/solid flow are a required measurement in validating the gas and solids flow structure predicted by computational fluid dynamic (CFD) models in fluid bed and transport reactors. The high concentration and velocities of solids, however, make the use of traditional gas velocity measurement devices such as pitot tubes, hot wire anemometers and other such devices difficult. A method of determining these velocities has been devised at the National Energy Technology Laboratory employing tracer gas. The technique developed measures the time average local axial velocity gas component of a gas/solid flow using an injected tracer gas which induces changes in the heat transfer characteristics of the gas mixture. A small amount of helium is injected upstream a known distance from a self-heated thermistor. The thermistor, protected from the solids by means of a filter, is exposed to gases that are continuously extracted from the flow. Changes in the convective heat transfer characteristics of the gas are indicated by voltage variations across a Wheatstone bridge. When pulsed injections of helium are introduced to the riser flow the change in convective heat transfer coefficient of the gas can be rapidly and accurately determined with this instrument. By knowing the separation distance between the helium injection point and the thermistor extraction location as well as the time delay between injection and detection, the gas velocity can easily be calculated. Variations in the measured gas velocities also allow the turbulence intensity of the gas to be estimated

  15. Application of process tomography in gas-solid fluidised beds in different scales and structures

    Science.gov (United States)

    Wang, H. G.; Che, H. Q.; Ye, J. M.; Tu, Q. Y.; Wu, Z. P.; Yang, W. Q.; Ocone, R.

    2018-04-01

    Gas-solid fluidised beds are commonly used in particle-related processes, e.g. for coal combustion and gasification in the power industry, and the coating and granulation process in the pharmaceutical industry. Because the operation efficiency depends on the gas-solid flow characteristics, it is necessary to investigate the flow behaviour. This paper is about the application of process tomography, including electrical capacitance tomography (ECT) and microwave tomography (MWT), in multi-scale gas-solid fluidisation processes in the pharmaceutical and power industries. This is the first time that both ECT and MWT have been applied for this purpose in multi-scale and complex structure. To evaluate the sensor design and image reconstruction and to investigate the effects of sensor structure and dimension on the image quality, a normalised sensitivity coefficient is introduced. In the meantime, computational fluid dynamic (CFD) analysis based on a computational particle fluid dynamic (CPFD) model and a two-phase fluid model (TFM) is used. Part of the CPFD-TFM simulation results are compared and validated by experimental results from ECT and/or MWT. By both simulation and experiment, the complex flow hydrodynamic behaviour in different scales is analysed. Time-series capacitance data are analysed both in time and frequency domains to reveal the flow characteristics.

  16. Non-intrusive measurement and hydrodynamics characterization of gas-solid fluidized beds: a review

    Science.gov (United States)

    Sun, Jingyuan; Yan, Yong

    2016-11-01

    Gas-solid fluidization is a well-established technique to suspend or transport particles and has been applied in a variety of industrial processes. Nevertheless, our knowledge of fluidization hydrodynamics is still limited for the design, scale-up and operation optimization of fluidized bed reactors. It is, therefore, essential to characterize the two-phase flow behaviours in gas-solid fluidized beds and monitor the fluidization processes for control and optimization. A range of non-intrusive techniques have been developed or proposed for measuring the fluidization dynamic parameters and monitoring the flow status without disturbing or distorting the flow fields. This paper presents a comprehensive review of the non-intrusive measurement techniques and the current state of knowledge and experience in the characterization and monitoring of gas-solid fluidized beds. These techniques are classified into six main categories as per sensing principles, electrostatic, acoustic emission and vibration, visualization, particle tracking, laser Doppler anemometry and phase Doppler anemometry as well as pressure-fluctuation methods. Trends and future developments in this field are also discussed.

  17. Study of Parameters Effect on Hydrodynamics of a Gas-Solid Chamber Experimentally and Numerically

    Directory of Open Access Journals (Sweden)

    Rahimzadeh Hassan

    2012-04-01

    Full Text Available In this research, gas velocity, initial static bed height and particle size effect on hydrodynamics of a non-reactive gas–solid fluidized bed chamber were studied experimentally and computationally. A multi fluid Eulerian model incorporating the kinetic theory for solid particles was applied to simulate the unsteady state behavior of this chamber and momentum exchange coefficients were calculated by using the Syamlal- O’Brien drag functions. Simulation results were compared with the experimental data in order to validate the CFD model. Pressure drops predicted by the simulations at different particle sizes and initial static bed height were in good agreement with experimental measurements at superficial gas velocity higher than the minimum fluidization velocity. Simulation results also indicated that small bubbles were produced at the bottom of the bed. These bubbles collided with each other as they moved upwards forming larger bubbles. Furthermore, this comparison showed that the model can predict hydrodynamic behavior of gas solid fluidized bed chambers reasonably well.

  18. Approximate deconvolution model for the simulation of turbulent gas-solid flows: An a priori analysis

    Science.gov (United States)

    Schneiderbauer, Simon; Saeedipour, Mahdi

    2018-02-01

    Highly resolved two-fluid model (TFM) simulations of gas-solid flows in vertical periodic channels have been performed to study closures for the filtered drag force and the Reynolds-stress-like contribution stemming from the convective terms. An approximate deconvolution model (ADM) for the large-eddy simulation of turbulent gas-solid suspensions is detailed and subsequently used to reconstruct those unresolved contributions in an a priori manner. With such an approach, an approximation of the unfiltered solution is obtained by repeated filtering allowing the determination of the unclosed terms of the filtered equations directly. A priori filtering shows that predictions of the ADM model yield fairly good agreement with the fine grid TFM simulations for various filter sizes and different particle sizes. In particular, strong positive correlation (ρ > 0.98) is observed at intermediate filter sizes for all sub-grid terms. Additionally, our study reveals that the ADM results moderately depend on the choice of the filters, such as box and Gaussian filter, as well as the deconvolution order. The a priori test finally reveals that ADM is superior compared to isotropic functional closures proposed recently [S. Schneiderbauer, "A spatially-averaged two-fluid model for dense large-scale gas-solid flows," AIChE J. 63, 3544-3562 (2017)].

  19. Improvements in or relating to process for the production of fuel gas from a carbonaceous solid

    Energy Technology Data Exchange (ETDEWEB)

    1952-12-03

    A process was designed for the generation of fuel gas from a solid carbonaceous fuel containing volatilizable constituents, which comprises admixing the solid carbonaceous fuel in particle form with sufficient water to form a fluid suspension, passing the suspension through a heating zone at an elevated temperature such that substantially all of the water is vaporized, thereby forming a dispersion of coal in steam and causing the dispersion to attain a velocity of at least 60 ft. per second to shatter the particles of coal by collision, passing the resulting dispersion into a fluidized bed of solid carbonaceous material in a methanization zone into contact with carbon monoxide and hydrogen at a temperature within the range of from 900/sup 0/ to 1,800/sup 0/F whereby carbon monoxide and hydrogen are converted to methane and volatilizable constituents of the solid carbonaceous material are distilled therefrom, withdrawing carbonaceous material from the methanization zone and passing it into contact with oxygen and steam in dilute phase in a gasification zone maintained at a temperature within the range of 2,000/sup 0/ to about 3,000/sup 0/F, passing the resulting gases comprising carbon monoxide and hydrogen from the gasification zone into the methanization zone as the source of carbon monoxide and hydrogen, and discharging the gaseous products of the methanization zone as the raw-product fuel gas.

  20. Annealing behaviour of high-dose rare-gas implantations into silicon

    International Nuclear Information System (INIS)

    Williams, J.S.; Grant, W.A.

    1976-01-01

    The annealing behaviour of 13 -10 17 ions/cm 2 is investigated by RBS and channelling techniques. There appears to be a strong correlation between the degree and nature of the post-anneal (above 650 0 C) remnant Si disorder, the implanted gas concentration and subsequent out-diffusion of the gas species. During the out-diffusion process a fraction of the gas (always less than 10 15 cm -2 ) remains trapped at, or beyond, the ion range and some of the diffusing gas becomes trapped near the target surface; for implantation doses below 10 15 cm -2 , no out-diffusion is observed up to 850 0 C. This behaviour is discussed in terms of the defect structure of the recrystallized implant layer. (author)

  1. Possibilities of mercury removal in the dry flue gas cleaning lines of solid waste incineration units.

    Science.gov (United States)

    Svoboda, Karel; Hartman, Miloslav; Šyc, Michal; Pohořelý, Michael; Kameníková, Petra; Jeremiáš, Michal; Durda, Tomáš

    2016-01-15

    Dry methods of the flue gas cleaning (for HCl and SO2 removal) are useful particularly in smaller solid waste incineration units. The amount and forms of mercury emissions depend on waste (fuel) composition, content of mercury and chlorine and on the entire process of the flue gas cleaning. In the case of high HCl/total Hg molar ratio in the flue gas, the majority (usually 70-90%) of mercury is present in the form of HgCl2 and a smaller amount in the form of mercury vapors at higher temperatures. Removal of both main forms of mercury from the flue gas is dependent on chemical reactions and sorption processes at the temperatures below approx. 340 °C. Significant part of HgCl2 and a small part of elemental Hg vapors can be adsorbed on fly ash and solid particle in the air pollution control (APC) processes, which are removed in dust filters. Injection of non-impregnated active carbon (AC) or activated lignite coke particles is able to remove mainly the oxidized Hg(2+) compounds. Vapors of metallic Hg(o) are adsorbed relatively weakly. Much better chemisorption of Hg(o) together with higher sorbent capacity is achieved by AC-based sorbents impregnated with sulfur, alkali poly-sulfides, ferric chloride, etc. Inorganic sorbents with the same or similar chemical impregnation are also applicable for deeper Hg(o) removal (over 85%). SCR catalysts convert part of Hg(o) into oxidized compounds (HgO, HgCl2, etc.) contributing to more efficient Hg removal, but excess of NH3 has a negative effect. Both forms, elemental Hg(o) and HgCl2, can be converted into HgS particles by reacting with droplets/aerosol of poly-sulfides solutions/solids in flue gas. Mercury captured in the form of water insoluble HgS is more advantageous in the disposal of solid waste from APC processes. Four selected options of the dry flue gas cleaning with mercury removal are analyzed, assessed and compared (in terms of efficiency of Hg-emission reduction and costs) with wet methods and retrofits for more

  2. Secondary ions produced from condensed rare gas targets under highly charged MeV/amu heavy ion bombardment

    International Nuclear Information System (INIS)

    Tawara, H.; Tonuma, T.; Kumagai, H.; Matsuo, T.

    1994-01-01

    Secondary ions produced from condensed rare gas targets are observed under MeV/amu, highly charged, heavy ion impact. The intensities of the observed cluster ions decrease smoothly as the cluster sizes become large but show some discontinuities at particular sizes of cluster ions. This seems to be closely related to the stabilities of cluster ion structures. It is also noted that very few doubly charged or practically no triply/higher charged ions have been observed, in sharp contrast to that of some condensed molecular targets. (orig.)

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

    International Nuclear Information System (INIS)

    Gill, R.L.

    1977-10-01

    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

  4. Multiple Multidentate Halogen Bonding in Solution, in the Solid State, and in the (Calculated) Gas Phase.

    Science.gov (United States)

    Jungbauer, Stefan H; Schindler, Severin; Herdtweck, Eberhardt; Keller, Sandro; Huber, Stefan M

    2015-09-21

    The binding properties of neutral halogen-bond donors (XB donors) bearing two multidentate Lewis acidic motifs toward halides were investigated. Employing polyfluorinated and polyiodinated terphenyl and quaterphenyl derivatives as anion receptors, we obtained X-ray crystallographic data of the adducts of three structurally related XB donors with tetraalkylammonium chloride, bromide, and iodide. The stability of these XB complexes in solution was determined by isothermal titration calorimetry (ITC), and the results were compared to X-ray analyses as well as to calculated binding patterns in the gas phase. Density functional theory (DFT) calculations on the gas-phase complexes indicated that the experimentally observed distortion of the XB donors during multiple multidentate binding can be reproduced in 1:1 complexes with halides, whereas adducts with two halides show a symmetric binding pattern in the gas phase that is markedly different from the solid state structures. Overall, this study demonstrates the limitations in the transferability of binding data between solid state, solution, and gas phase in the study of complex multidentate XB donors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Solid electrolyte gas sensors based on cyclic voltammetry with one active electrode

    Energy Technology Data Exchange (ETDEWEB)

    Jasinski, G; Jasinski, P, E-mail: gregor@biomed.eti.pg.gda.pl [Gdansk University of Technology, Faculty of Electronics, Telecommunication and Informatics, Narutowicza 11/12, 80-233 Gdansk (Poland)

    2011-10-29

    Solid state gas sensors are cost effective, small, rugged and reliable. Typically electrochemical solid state sensors operate in either potentiometric or amperometric mode. However, a lack of selectivity is sometimes a shortcoming of such sensors. It seems that improvements of selectivity can be obtained in case of the electrocatalytic sensors, which operate in cyclic voltammetry mode. Their working principle is based on acquisition of an electric current, while voltage ramp is applied to the sensor. The current-voltage response depends in a unique way on the type and concentration of ambient gas. Most electrocatalytic sensors have symmetrical structure. They are in a form of pellets with two electrodes placed on their opposite sides. Electrochemical reactions occur simultaneously on both electrodes. In this paper results for sensors with only one active electrode exposed to ambient gas are presented. The other electrode was isolated from ambient gas with dielectric sealing. This sensor construction allows application of advanced measuring procedures, which permit sensor regeneration acceleration. Experiments were conducted on Nasicon sensors. Properties of two sensors, one with one active electrode and second with symmetrical structure, used for the detection of mixtures of NO{sub 2} and synthetic air are compared.

  6. Excited argon 1s5 production in micro-hollow cathode discharges for use as potential rare gas laser sources

    Science.gov (United States)

    Peterson, Richard D.; Eshel, Ben; Rice, Christopher A.; Perram, Glen P.

    2018-02-01

    The diode-pumped rare gas laser (DPRGL) has been suggested as a potential high-gain, high-energy laser which requires densities on the order of 1013 cm-3 at pressures around 1 atmosphere for efficient operation. Argon 1s5 number densities have been measured in micro-hollow cathode discharges with electrode gaps of 127 and 254 μm and hole diameters from 100-400 μm. The dependency of the metastable argon (1s5) density on total gas pressure, electrode gap distance and hole diameter were explored. The measured densities were all in the range of 0.5 - 2 × 1013 cm-3 with the 400 μm hole diameters being the lowest.

  7. Control oriented modeling of ejector in anode gas recirculation solid oxygen fuel cell systems

    International Nuclear Information System (INIS)

    Zhu Yinhai; Li Yanzhong; Cai Wenjian

    2011-01-01

    A one-equation model is proposed for fuel ejector in anode gas recirculation solid oxide fuel cell (SOFC) system. Firstly, the fundamental governing equations are established by employing the thermodynamic, fluid dynamic principles and chemical constraints inside the ejector; secondly, the one-equation model is derived by using the parameter analysis and lumped-parameter method. Finally, the computational fluid dynamics (CFD) technique is employed to obtain the source data for determining the model parameters. The effectiveness of the model is studied under a wide range of operation conditions. The effect of ejector performance on the anode gas recirculation SOFC system is also discussed. The presented model, which only contains four constant parameters, is useful in real-time control and optimization of fuel ejector in the anode gas recirculation SOFC system.

  8. Light olefins from synthesis gas using ruthenium on rare earth oxide catalysts

    International Nuclear Information System (INIS)

    Bruce, L.; Hardin, S.; Hoang, M.; Turney, T.

    1988-01-01

    The interaction of ruthenium carbonyl, Ru/sub 3/(CO)/sub 12/ with rare earth oxides of high surface area, >50m/sup 2/g/sup -1/, has been studied. [Ru/sub 3/(μ H)(CO)/sub 10/(μ-OM=)] is formed on holmia, but on lanthana only [Ru(CO)/sub 2/]/sub n/ species are observed. Reduction of the carbonyl ligands takes place at <573K to give catalysts for the hydrogenation of carbon monoxide with activity and selectivity dependent on the particular rare earth oxide and pretreatment. Over ceria, the product is up to 55 wt% C2-5 olefins. A similar selectivity is obtained over lanthana only after redispersion through a reduction-oxidation-reduction cycle

  9. Development of solid-gas equilibrium propulsion system for small spacecraft

    Science.gov (United States)

    Chujo, Toshihiro; Mori, Osamu; Kubo, Yuki

    2017-11-01

    A phase equilibrium propulsion system is a kind of cold-gas jet in which the phase equilibrium state of the fuel is maintained in a tank and its vapor is ejected when a valve is opened. One such example is a gas-liquid equilibrium propulsion system that uses liquefied gas as fuel. This system was mounted on the IKAROS solar sail and has been demonstrated in orbit. The system has a higher storage efficiency and a lighter configuration than a high-pressure cold-gas jet because the vapor pressure is lower, and is suitable for small spacecraft. However, the system requires a gas-liquid separation device in order to avoid leakage of the liquid, which makes the system complex. As another example of a phase equilibrium propulsion system, we introduce a solid-gas equilibrium propulsion system, which uses a sublimable substance as fuel and ejects its vapor. This system has an even lower vapor pressure and does not require such a separation device, instead requiring only a filter to keep the solid inside the tank. Moreover, the system is much simpler and lighter, making it more suitable for small spacecraft, especially CubeSat-class spacecraft, and the low thrust of the system allows spacecraft motion to be controlled precisely. In addition, the thrust level can be controlled by controlling the temperature of the fuel, which changes the vapor pressure. The present paper introduces the concept of the proposed system, and describes ejection experiments and its evaluation. The basic function of the proposed system is demonstrated in order to verify its usefulness.

  10. Greenhouse Gas Emissions from Solid and Liquid Organic Fertilizers Applied to Lettuce.

    Science.gov (United States)

    Toonsiri, Phasita; Del Grosso, Stephen J; Sukor, Arina; Davis, Jessica G

    2016-11-01

    Improper application of nitrogen (N) fertilizer and environmental factors can cause the loss of nitrous oxide (NO) to the environment. Different types of fertilizers with different C/N ratios may have different effects on the environment. The focus of this study was to evaluate the effects of environmental factors and four organic fertilizers (feather meal, blood meal, fish emulsion, and cyano-fertilizer) applied at different rates (0, 28, 56, and 112 kg N ha) on NO emissions and to track CO emissions from a lettuce field ( L.). The study was conducted in 2013 and 2014 and compared preplant-applied solid fertilizers (feather meal and blood meal) and multiple applications of liquid fertilizers (fish emulsion and cyano-fertilizer). Three days a week, NO and CO emissions were measured twice per day in 2013 and once per day in 2014 using a closed-static chamber, and gas samples were analyzed by gas chromatography. Preplant-applied solid fertilizers significantly increased cumulative NO emissions as compared with control, but multiple applications of liquid fertilizers did not. Emission factors for NO ranged from 0 to 0.1% for multiple applications of liquid fertilizers and 0.6 to 11% for preplant-applied solid fertilizers, which could be overestimated due to chamber placement over fertilizer bands. In 2014, solid fertilizers with higher C/N ratios (3.3-3.5) resulted in higher CO emissions than liquid fertilizers (C/N ratio, 0.9-1.5). Therefore, organic farmers should consider the use of multiple applications of liquid fertilizers as a means to reduce soil greenhouse gas emissions while maintaining high yields. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  11. Fullerene-rare gas mixed plasmas in an electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Asaji, T., E-mail: asaji@oshima-k.ac.jp; Ohba, T. [Oshima National College of Maritime Technology, 1091-1 Komatsu, Suo-oshima, Oshima, Yamaguchi 742-2193 (Japan); Uchida, T.; Yoshida, Y. [Bio-Nano Electronics Research Centre, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan); Minezaki, H.; Ishihara, S. [Graduate School of Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan); Racz, R.; Biri, S. [Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem Tér 18/c (Hungary); Muramatsu, M.; Kitagawa, A. [National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kato, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2014-02-15

    A synthesis technology of endohedral fullerenes such as Fe@C{sub 60} has developed with an electron cyclotron resonance (ECR) ion source. The production of N@C{sub 60} was reported. However, the yield was quite low, since most fullerene molecules were broken in the ECR plasma. We have adopted gas-mixing techniques in order to cool the plasma and then reduce fullerene dissociation. Mass spectra of ion beams extracted from fullerene-He, Ar or Xe mixed plasmas were observed with a Faraday cup. From the results, the He gas mixing technique is effective against fullerene destruction.

  12. Development of acoustic flow instruments for solid/gas pipe flows

    International Nuclear Information System (INIS)

    Sheen, S.H.; Raptis, A.C.

    1986-05-01

    Two nonintrusive acoustic flow sensing techniques are reported. One technique, passive in nature, simply measures the bandpassed acoustic noise level produced by particle/particle and particle/wall collisions. The noise levels, given in true RMS voltages or in autocorrelations, show a linear relationship to particle velocity but increase with solid concentration. Therefore, the passive technique requires calibration and a separate measure of solid concentration before it can be used to monitor the particle velocity. The second technique is based on the active cross-correlation principle. It measures particle velocity directly by correlating flow-related signatures at two sensing stations. The velocity data obtained by this technique are compared with measurements by a radioactive-particle time-of-flight (TOF) method. A multiplier of 1.53 is required to bring the acoustic data into agreement with the radioactive TOF result. The difference may originate from the difference in flow fields where particles are detected. The radioactive method senses particles mainly in the turbulent region and essentially measures average particle velocity across the pipe, while the acoustic technique detects particles near the pipe wall, and so measures the particle velocity in the viscous sublayer. Both techniques were tested in flows of limestone and air and 1-mm glass beads and air at the Argonne National Laboratory Solid/Gas Test Facility (SGFTF). The test matrix covered solid velocities of 20 to 30 m/s in a 2-in. pipe and solid-to-gas loading ratios of 6 to 22. 37 refs., 19 figs., 4 tabs

  13. Assessment of potential greenhouse gas mitigation of available household solid waste treatment technologies

    Directory of Open Access Journals (Sweden)

    Hoang Minh Giang

    2013-11-01

    Full Text Available Current household solid waste treatment practices in most cities in Vietnam caused a great amount of direct greenhouse gas (GHG emissions. Available solid waste treatment technologies should be seriously taken  into consideration as a wedge of GHG mitigation in waste sector base on presently Vietnamese economic conditions. This study aim to evaluate the potential amount of GHG mitigation from current domestic solid waste treatment technologies in Vietnam including landfills and composting from various management scenarios. In oder to use Tier 2 model of IPCC 2006 for GHG estimation from landfills, an analysis on current household solid waste management system of the city was obtained by using material flow analysis approach. A case study in Hanoi, the capital city of Vietnam was carried out in this research. As a result, there was a reduced of over 70% of the amount of CH4 emissions and  up to 53% of total GHG saving (CO2-eq from avoiding organic waste to landfill. In addition, applying an energy recovery from LFG system to available landfills would lead to aproximately 75% of GHG saved compare to current emission of waste sector.Doi: http://dx.doi.org/10.12777/wastech.1.1.10-16Citation: Giang, H.M.,Luong, N.D., and Huong, L.T.M.2013. Assessment of potential greenhouse gas mitigation of available household solid waste treatment technologies. . Waste Technology 1(1:6-9. Doi: http://dx.doi.org/10.12777/wastech.1.1.10-16

  14. HM{sup +}–RG complexes (M = group 2 metal; RG = rare gas): Physical vs. chemical interactions

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Joe P.; Dodson, Hannah; Wright, Timothy G., E-mail: Tim.Wright@nottingham.ac.uk [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Breckenridge, W. H. [Department of Chemistry, University of Utah, Salt Lake City, Utah 84112 (United States)

    2015-04-21

    Previous work on the HM{sup +}–He complexes (M = Be–Ra) has been extended to the cases of the heavier rare gas atoms, HM{sup +}–RG (RG = Ne–Rn). Optimized geometries and harmonic vibrational frequencies have been calculated using MP2 theory and quadruple-ζ quality basis sets. Dissociation energies for the loss of the rare gas atom have been calculated at these optimized geometries using coupled cluster with single and double excitations and perturbative triples, CCSD(T)theory, extrapolating interaction energies to the basis set limit. Comparisons are made between the present data and the previously obtained helium results, as well as to those of the bare HM{sup +} molecules; furthermore, comparisons are made to the related M{sup +}–RG and M{sup 2+}–RG complexes. Partial atomic charge analyses have also been undertaken, and these used to test a simple charge-induced dipole model. Molecular orbital diagrams are presented together with contour plots of the natural orbitals from the quadratic configuration with single and double excitations (QCISD) density. The conclusion is that the majority of these complexes are physically bound, with very little sharing of electron density; however, for M = Be, and to a lesser extent M = Mg, some evidence for chemical effects is seen in HM{sup +}–RG complexes involving RG atoms with the higher atomic numbers.

  15. Precious metals and rare earth elements in municipal solid waste – Sources and fate in a Swiss incineration plant

    Energy Technology Data Exchange (ETDEWEB)

    Morf, Leo S., E-mail: leo.morf@bd.zh.ch [Baudirektion Kanton Zürich, Amt für Abfall, Wasser, Energie und Luft, Zurich (Switzerland); Gloor, Rolf; Haag, Olaf [Bachema AG, Schlieren (Switzerland); Haupt, Melanie [Zentrum für nachhaltige Abfall-und Ressourcennutzung ZAR, Hinwil (Switzerland); Skutan, Stefan [Bachema AG, Schlieren (Switzerland); Lorenzo, Fabian Di; Böni, Daniel [Zentrum für nachhaltige Abfall-und Ressourcennutzung ZAR, Hinwil (Switzerland)

    2013-03-15

    Highlights: ► We carefully addressed all the very valuable comments and suggestions of the reviewers. ► We also have shortened the size of the paper and tried simplify it substantially, as requested by the reviewers (introduction 25% reduced!). ► We have decided to take the chance and have replaced the data for the “additional” elements (Cu, Cd, Zn, Pb, Sn, Cr, Ni, Fe, Al) of the earlier MFA (Morf, 2011) with data that belong to the samples of this study. ► We are convinced that with the revision the paper has significantly improved in quality and attractiveness. - Abstract: In Switzerland many kinds of waste, e.g. paper, metals, electrical and electronic equipment are separately collected and recycled to a large extent. The residual amount of municipal solid waste (MSW) has to be thermally treated before final disposal. Efforts to recover valuable metals from incineration residues have recently increased. However, the resource potential of critical elements in the waste input (sources) and their partitioning into recyclable fractions and residues (fate) is unknown. Therefore, a substance flow analysis (SFA) for 31 elements including precious metals (Au, Ag), platinum metal group elements (Pt, Rh) and rare earth elements (La, Ce, etc.) has been conducted in a solid waste incinerator (SWI) with a state-of-the-art bottom ash treatment according to the Thermo-Re® concept. The SFA allowed the determination of the element partitioning in the SWI, as well as the elemental composition of the MSW by indirect analysis. The results show that the waste-input contains substantial quantities of precious metals, such as 0.4 ± 0.2 mg/kg Au and 5.3 ± 0.7 mg/kg Ag. Many of the valuable substances, such as Au and Ag are enriched in specific outputs (e.g. non-ferrous metal fractions) and are therefore recoverable. As the precious metal content in MSW is expected to rise due to its increasing application in complex consumer products, the results of this study are

  16. Precious metals and rare earth elements in municipal solid waste – Sources and fate in a Swiss incineration plant

    International Nuclear Information System (INIS)

    Morf, Leo S.; Gloor, Rolf; Haag, Olaf; Haupt, Melanie; Skutan, Stefan; Lorenzo, Fabian Di; Böni, Daniel

    2013-01-01

    Highlights: ► We carefully addressed all the very valuable comments and suggestions of the reviewers. ► We also have shortened the size of the paper and tried simplify it substantially, as requested by the reviewers (introduction 25% reduced!). ► We have decided to take the chance and have replaced the data for the “additional” elements (Cu, Cd, Zn, Pb, Sn, Cr, Ni, Fe, Al) of the earlier MFA (Morf, 2011) with data that belong to the samples of this study. ► We are convinced that with the revision the paper has significantly improved in quality and attractiveness. - Abstract: In Switzerland many kinds of waste, e.g. paper, metals, electrical and electronic equipment are separately collected and recycled to a large extent. The residual amount of municipal solid waste (MSW) has to be thermally treated before final disposal. Efforts to recover valuable metals from incineration residues have recently increased. However, the resource potential of critical elements in the waste input (sources) and their partitioning into recyclable fractions and residues (fate) is unknown. Therefore, a substance flow analysis (SFA) for 31 elements including precious metals (Au, Ag), platinum metal group elements (Pt, Rh) and rare earth elements (La, Ce, etc.) has been conducted in a solid waste incinerator (SWI) with a state-of-the-art bottom ash treatment according to the Thermo-Re® concept. The SFA allowed the determination of the element partitioning in the SWI, as well as the elemental composition of the MSW by indirect analysis. The results show that the waste-input contains substantial quantities of precious metals, such as 0.4 ± 0.2 mg/kg Au and 5.3 ± 0.7 mg/kg Ag. Many of the valuable substances, such as Au and Ag are enriched in specific outputs (e.g. non-ferrous metal fractions) and are therefore recoverable. As the precious metal content in MSW is expected to rise due to its increasing application in complex consumer products, the results of this study are

  17. Gas chromatography of adducts of rare earth dipivaloylmethanates with triphenylphosphine oxide

    International Nuclear Information System (INIS)

    Magazeeva, N.V.; Martynenko, L.I.; Murav'eva, I.A.; Spitsyn, V.I.

    1987-01-01

    A gas chromatographic method for determination of stability provisional constants of dipivaloylmethanates of REE with triphenylphosphine oxide is suggested, and ML 3 xTPPO adduct stability is shown to decrease in Ho-Lu series. ML 3 chromatographing at the presence of TPPO is stated to increase the coefficients of REE separation

  18. Eu/RG absorption and excitation spectroscopy in the solid rare gases: state dependence of crystal field splitting and Jahn-Teller coupling.

    Science.gov (United States)

    Byrne, Owen; McCaffrey, John G

    2011-03-28

    Absorption spectroscopy recorded for annealed samples of matrix-isolated atomic europium reveals a pair of thermally stable sites in Ar and Kr while a single site exists in Xe. Plots of the matrix shifts of the visible s → p bands versus host polarizability, allowed the association of the single site in Xe and the blue sites in Ar and Kr. On the basis of the similar ground state bond lengths expected for the Eu-rare gas (RG) diatomics and the known Na-RG molecules, the blue sites are attributed to Eu occupancy in the smaller tetra-vacancy while the red sites are proposed to arise from hexa-vacancy sites. Both sites are of cubic symmetry, consistent with the pronounced Jahn-Teller structure present on the y(8)P ← a(8)S(7/2) transition for these bands in the three hosts studied. Site-selective excitation spectroscopy has been used to reanalyze complex absorption spectra previously published by Jakob et al. [Phys. Lett. A 57, 67 (1976)] for the near-UV f → d transitions. On the basis that a pair of thermally stable sites exist in solid argon, the occurrence of crystal field splitting has been identified to occur for the J ≥ 5/2 level of the (8)P state when isolated in these two sites with cubic symmetry. From a detailed lineshape analysis, the magnitude of the crystal field splittings on the J = 5/2 level in Ar is found to be 105 and 123 cm(-1) for the red and blue sites, respectively.

  19. Digital image processing based mass flow rate measurement of gas/solid two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Song Ding; Peng Lihui; Lu Geng; Yang Shiyuan [Tsinghua National Laboratory for Information Science and Technology, Department of Automation, Tsinghua University, Beijing, 100084 (China); Yan Yong, E-mail: lihuipeng@tsinghua.edu.c [University of Kent, Canterbury, Kent CT2 7NT (United Kingdom)

    2009-02-01

    With the rapid growth of the process industry, pneumatic conveying as a tool for the transportation of a wide variety of pulverized and granular materials has become widespread. In order to improve plant control and operational efficiency, it is essential to know the parameters of the particle flow. This paper presents a digital imaging based method which is capable of measuring multiple flow parameters, including volumetric concentration, velocity and mass flow rate of particles in the gas/solid two phase flow. The measurement system consists of a solid state laser for illumination, a low-cost CCD camera for particle image acquisition and a microcomputer with bespoke software for particle image processing. The measurements of particle velocity and volumetric concentration share the same sensing hardware but use different exposure time and different image processing methods. By controlling the exposure time of the camera a clear image and a motion blurred image are obtained respectively. The clear image is thresholded by OTSU method to identify the particles from the dark background so that the volumetric concentration is determined by calculating the ratio between the particle area and the total area. Particle velocity is derived from the motion blur length, which is estimated from the motion blurred images by using the travelling wave equation method. The mass flow rate of particles is calculated by combining the particle velocity and volumetric concentration. Simulation and experiment results indicate that the proposed method is promising for the measurement of multiple parameters of gas/solid two-phase flow.

  20. Digital image processing based mass flow rate measurement of gas/solid two-phase flow

    International Nuclear Information System (INIS)

    Song Ding; Peng Lihui; Lu Geng; Yang Shiyuan; Yan Yong

    2009-01-01

    With the rapid growth of the process industry, pneumatic conveying as a tool for the transportation of a wide variety of pulverized and granular materials has become widespread. In order to improve plant control and operational efficiency, it is essential to know the parameters of the particle flow. This paper presents a digital imaging based method which is capable of measuring multiple flow parameters, including volumetric concentration, velocity and mass flow rate of particles in the gas/solid two phase flow. The measurement system consists of a solid state laser for illumination, a low-cost CCD camera for particle image acquisition and a microcomputer with bespoke software for particle image processing. The measurements of particle velocity and volumetric concentration share the same sensing hardware but use different exposure time and different image processing methods. By controlling the exposure time of the camera a clear image and a motion blurred image are obtained respectively. The clear image is thresholded by OTSU method to identify the particles from the dark background so that the volumetric concentration is determined by calculating the ratio between the particle area and the total area. Particle velocity is derived from the motion blur length, which is estimated from the motion blurred images by using the travelling wave equation method. The mass flow rate of particles is calculated by combining the particle velocity and volumetric concentration. Simulation and experiment results indicate that the proposed method is promising for the measurement of multiple parameters of gas/solid two-phase flow.

  1. Producer gas fuelling of a 20kW output engine by gasification of solid biomass

    Energy Technology Data Exchange (ETDEWEB)

    Hollingdale, A C; Breag, G R; Pearce, D

    1988-11-01

    Motive power requirements in the range up to 100 kW shaft power are common in developing country processing operations. Producer gas-fuelled systems based upon a relatively cheap and simple manually operated gasifier or reactor using readily available biomass feedstock can offer in some cases an attractive alternative to fossil-fuelled power units. This bulletin outlines research and development work by the Industrial Development Department of the Overseas Development Natural Resources Institute for 20 kW shaft power output from producer gas derived from solid biomass. Biomass materials such as wood or shells can be carbonized to form charcoal or left in the natural uncarbonized state. In this work both carbonized and uncarbonized biomass fuel has been used to provide producer gas to fuel a Ford 2274E engine, an industrial version of a standard vehicle spark-ignition engine. Cross-draught and down-draught reactor designs were evaluated during trials with this engine. Also different gas cleaning and cooling arrangements were tested. Particular emphasis was placed on practical aspects of reactor/engine operation. This work follows earlier work with a 4 kW shaft power output system using charcoal-derived producer gas. (author).

  2. The gas-solid trickle-flow reactor for the catalytic oxidation of hydrogen sulphide: a trickle-phase model

    NARCIS (Netherlands)

    Verver, A.B.; van Swaaij, Willibrordus Petrus Maria

    1987-01-01

    The oxidation of H2S by O2 producing elemental sulphur has been studied at temperatures of 100–300°C and at atmospheric pressure in a laboratory-scale gas-solid trickle-flow reactor. In this reactor one of the reaction products, i.e. sulphur, is removed continuously by flowing solids. A porous,

  3. Influence of Bubble-Bubble interactions on the macroscale circulation patterns in a bubbling gas-solid fluidized bed

    NARCIS (Netherlands)

    Laverman, J.A.; van Sint Annaland, M.; Kuipers, J.A.M.

    2007-01-01

    The macro-scale circulation patterns in the emulsion phase of a gas-solid fluidized bed in the bubbling regime have been studied with a 3D Discrete Bubble Model. It has been shown that bubble-bubble interactions strongly influence the extent of the solids circulation and the bubble size

  4. Recycling of rare earths from Hg-containing fluorescent lamp scraps by solid state chlorination; Rueckgewinnung Seltener Erden aus quecksilberbelasteten Leuchtstoffen mittels Feststoffchlorierung

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, Tom; Froehlich, Peter; Bertau, Martin [TU Bergakademie Freiberg (Germany); Golon, Katja [FNE Entsorgungsdienste GmbH, Freiberg (Germany)

    2015-10-15

    Solid state chlorination with NH{sub 4}Cl comprises a method for rare earth recycling apart from pyro- or hydrometallurgical strategies. The examined partially Hg-containing fluorescent lamp scraps are rich in rare earths like La, Ce, Tb and Gd, but especially in Y and Eu. By mixing with NH{sub 4}Cl and heating up to NH{sub 4}Cl decomposition temperature in a sublimation reactor, Y and Eu could be transferred selectively into their respective metal chlorides with high yields. The yield and selectivity depend on temperature and the ratio of NH{sub 4}Cl to fluorescent lamp scraps, which were varied systematically.

  5. Valorization of Calcium Carbonate-Based Solid Wastes for the Treatment of Hydrogen Sulfide from the Gas Phase

    OpenAIRE

    Pham Xuan , Huynh; Pham Minh , Doan; Galera Martinez , Marta; Nzihou , Ange; Sharrock , Patrick

    2015-01-01

    International audience; This paper focuses on the valorization of calcium carbonate-based solid wastes for theremoval of hydrogen sulfide from gas phase. Two solid wastes taken from industrial sites for theproduction of sodium carbonate and sodium bicarbonate by the Solvay process® were analyzedby different physico-chemical methods. Calcium carbonate was found as the main component ofboth the solid wastes. Trace amounts of other elements such as Mg, Al, Fe, Si, Cl, Na etc. werealso present in...

  6. Simple and double two-colour photoionization of rare gas atoms

    International Nuclear Information System (INIS)

    Guyetand, O.

    2008-05-01

    The present work deals with simple and double ionization of rare gases by harmonic radiation produced by, and combined with, an intense femtosecond infrared laser. Technical aspects related to the use of harmonic generation and to the detection of ions and electrons in coincidence are exposed. Theoretical background for two colour, few-photon, single and double ionization is detailed. Spectra and angular distributions of the photoelectrons measured in helium are described and compared with TDSE (time-dependent Schroedinger equation) theoretical calculations, for various conditions of the harmonic photons. The shape of the angular distributions can be explained within the frame of two distinct analytic approaches: the perturbation theory and the soft-photon approximation. The double ionization measurements have been performed on xenon, a complex atom characterized by many possible routes leading to double ionization. The analysis of energy and angular correlations of the two photoelectrons proves the feasibility of such experiments that combines harmonic and infrared radiations. It shows that two step processes are dominant in the case of xenon. This work appeals for extending few-photon, double ionization experiments to lighter rare gases. (author)

  7. Study of rare-gas dimer ions by the variational cellular method

    International Nuclear Information System (INIS)

    Wentzcovitch, R.M.M.

    1982-01-01

    The Variational Cellular Method to study ionized molecules in their ground and excited states with the scope of testing the validity of such method in these cases have been used. The ions studied are Ne +2 , Ar +2 , where the latter is the system with the largest number of electrons tested by VCM so far. The electronic transitions in these systems are important mechanisms of efficiency decay for the noble gas halide lasers ('excimer lasers'). (Author) [pt

  8. CO{sub 2} gas sensors based on rare earth oxycarbonates

    Energy Technology Data Exchange (ETDEWEB)

    Haensch, Alexander

    2016-07-01

    This title presents a new type of CO{sub 2} gas sensor, that allows the measurement of CO{sub 2} gas with very low effort. The measurement principle is based on two semiconducting materials. One the ''receptor'' and a ''transducer'' form a semiconductor junction. Electronic changes in the receptor change the electrical resistance in the transducer and therefor allow the easy electrical measurement. The reactivity and the reaction mechanism is thoroughly studied. In the first part the basics and resistance measurements are presented. A comparison between different mixtures is done. The main part studies the surface chemistry with operando DRIFT spectroscopy. The chemical reactivity of different target gases and background gases is studied thoroughly. The electronic properties of Oxycarbonates and the combination of oxycarbonate and tin oxide were studied using operando Kelvin probes measurements. The result is that CO{sub 2} alters the electron affinity of the material. Once moisture is present, an additional band bending is visible. The band bending dominated in a humid atmosphere, the work function changes. The electronic connection of oxycarbonate and tin oxide, the work function change of Oxycarbonates can be transferred to the tin oxide. Using the collected data, a basic idea of the operation will be presented by a two-semiconductor materials gas sensor.

  9. Gas suspension flows of a moderately dense binary mixture of solid particles in vertical tubes

    Energy Technology Data Exchange (ETDEWEB)

    Zamankhan, P.; Huotari, J. [VTT Energy, Jyvaeskylae (Finland). Combustion and Conversion Lab.

    1996-12-01

    The turbulent, steady, fully-developed flow of a moderately dense (solid volume faction >>0.001) binary mixture of spherical particles in a gaseous carrier is investigated for the case of flow in a vertical riser. The suspended particles are considered to be in turbulent motion, driven by random aerodynamic forces acting between the particle and the gaseous carrier as well as particle-particle interactive forces. A model is constructed based on the combination of the time-averaged after volume-averaged conservation equations of mass, momentum and mechanical energy of the gas phase in the continuum theory and the corresponding equations for the solid particles obtained using the recently developed Enskog theory for dense multi-component mixtures of slightly inelastic spherical particles. The model properly takes into account the contributions of particle-particle collisions, as well as the fluid-dynamic fluctuating forces on individual particles. To demonstrate the validity of this approach, the fully-developed steady-state mean velocity and concentration distributions of a moderately dense binary mixture of solid particles in a turbulent vertical flow calculated by the present model are compared with available experimental measurements. The results provide a qualitative description of the experimentally observed motion of coarse particles in a fast bed of fine solids. (author)

  10. Electron probe micro-analysis of gas bubbles in solids: a novel approach

    International Nuclear Information System (INIS)

    Verwerft, M.; Vos, B.

    1999-01-01

    The local analysis of retained noble gas in nuclear fuel is inherently difficult since the physical form under which it is stored varies from atomically dispersed to bubbles with a diameter of several hundreds of nanometers. One of the techniques that has been applied since pore than twenty years is EPMA. Although many important results have been obtained with this technique, its application to the analysis of highly inhomogeneous materials is limited. The EPMA technique is indeed difficult to apply to samples that are not homogeneous on the scale of the electron-solid interaction volume. The paper discusses the development of a method to analyse a system of as bubbles distributed in a solid matrix. This method has been based on a multiple voltage EPMA measurement combined with a scanning Electron Microscopic analysis of the bubble size distribution

  11. Revisiting low-fidelity two-fluid models for gas-solids transport

    Science.gov (United States)

    Adeleke, Najeem; Adewumi, Michael; Ityokumbul, Thaddeus

    2016-08-01

    Two-phase gas-solids transport models are widely utilized for process design and automation in a broad range of industrial applications. Some of these applications include proppant transport in gaseous fracking fluids, air/gas drilling hydraulics, coal-gasification reactors and food processing units. Systems automation and real time process optimization stand to benefit a great deal from availability of efficient and accurate theoretical models for operations data processing. However, modeling two-phase pneumatic transport systems accurately requires a comprehensive understanding of gas-solids flow behavior. In this study we discuss the prevailing flow conditions and present a low-fidelity two-fluid model equation for particulate transport. The model equations are formulated in a manner that ensures the physical flux term remains conservative despite the inclusion of solids normal stress through the empirical formula for modulus of elasticity. A new set of Roe-Pike averages are presented for the resulting strictly hyperbolic flux term in the system of equations, which was used to develop a Roe-type approximate Riemann solver. The resulting scheme is stable regardless of the choice of flux-limiter. The model is evaluated by the prediction of experimental results from both pneumatic riser and air-drilling hydraulics systems. We demonstrate the effect and impact of numerical formulation and choice of numerical scheme on model predictions. We illustrate the capability of a low-fidelity one-dimensional two-fluid model in predicting relevant flow parameters in two-phase particulate systems accurately even under flow regimes involving counter-current flow.

  12. Developments in, and environmental impacts of, electricity generation from municipal solid waste and landfill gas combustion

    International Nuclear Information System (INIS)

    Porteous, A.

    1993-01-01

    The 1991 NFFO allocations for renewable energy generation are reviewed with emphasis on electricity from municipal solid waste (MSW) and landfill gas (LFG) combustion tranches. The implications of materials recovery on the calorific value of MSW are considered, as are the environmental impacts of both MSW and LFG combustion with special reference to air pollutant emissions. The performance and economics of state of the art incineration and LFG power generating plants are examined. It is shown that energy recovery from these wastes can be both cost effective and environmentally desirable. (Author)

  13. Evolution of weak perturbations in gas-solid suspension with chemical reaction

    Energy Technology Data Exchange (ETDEWEB)

    Sharypov, O.V. [Russian Academy of Sciences, Novosibirsk (Russian Federation). Inst. of Thermophysics; Novosibirsk State Univ. (Russian Federation); Anufriev, I.S. [Novosibirsk State Univ. (Russian Federation)

    2013-07-01

    Dynamics of weak finite-amplitude perturbations in two-phase homogeneous medium (gas + solid particles) with non-equilibrium chemical reaction in gas is studied theoretically. Non-linear model of plane perturbation evolution is substantiated. The model takes into account wave-kinetic interaction and dissipation effects, including inter-phase heat and momentum transfer. Conditions for uniform state of the system are analyzed. Non-linear equation describing evolution of plane perturbation is derived under weak dispersion and dissipation effects. The obtained results demonstrate self-organization in the homogeneous system: steady-state periodic structure arises, its period, amplitude and velocity depends on the features of the medium. The dependencies of these parameters on dissipation and chemical kinetics are analyzed.

  14. Pre-reforming of natural gas in solid oxide fuel-cell systems

    Energy Technology Data Exchange (ETDEWEB)

    Peters, R.; Riensche, E.; Cremer, P. [Institute for Materials and Processes Systems IWV 3: Energy Process Engineering, Forschungszentrum Juelich (Germany)

    2000-03-01

    Several measures concerning fuel processing in a solid oxide fuel cell (SOFC) system offer the possibility of significant cost reduction and higher system efficiencies. For SOFC systems, the ratio between internal and pre-reforming has to be optimized on the basis of experimental performance data. Furthermore, anode gas recycling by an injector in front of the pre-reformer can eliminate the steam generator and the corresponding heat of evaporation. A detailed study is carried out on pre-reforming in a reformer of considerable size (10 kW{sub el}). Simulating anode gas recycling with an injector, the influence of carbon dioxide on reactor performance was studied. Also, the dependence of the methanol conversion on mass flow and temperature will be discussed. In addition, some results concerning the dynamic behaviour of the pre-reformer are given. (orig.)

  15. Design optimisation of a hybrid solid oxide fuel cell and gas turbine power generation system

    Energy Technology Data Exchange (ETDEWEB)

    Williams, G.J.; Siddle, A.; Pointon, K.

    2001-07-01

    The objectives of the combined ALSTOM Power Technology and Advantica Technologies project are reported as: (a) to design a gas turbine (GT) unit compatible with a solid oxide fuel cell (SOFC) in a high efficiency power system and aimed at the Distributed Power application range of 1-20MW, and (b) to identify the main features and components of a 'Proof of Concept' hybrid unit of output around 0.1MW, based on existing or near-market technology. The study showed: (i) while the potential for high efficiency SOFC + GT hybrid cycles is clear, little effort has been put into the design of the gas turbine and some other components and (ii) there is room for commercial exploitation in the areas of both component manufacture and system supply.

  16. Adsorption process analysis at the solid-gas interface by the polarization phenomenon study

    International Nuclear Information System (INIS)

    Mouton-Chazel, V.

    1994-01-01

    In order to improve the safety of anti-gas filters users, the Cogema (Nuclear Materials General Company) has developed a gaseous pollutants saturation detection technology for respiratory protection masks. As a matter of fact, the problem consists in studying the surface properties of a solid. In this study the adsorption has been considered as a phenomenon which can be followed by a relatively simple electrical measure technology. A microscopic description of the adsorption phenomenon has been given at first and explained by the thermodynamics laws. Then a theoretical model has been elaborated. The developments which have been brought to this model in this work have allowed to give a satisfactory interpretation of the phenomena observed during the adsorption of a polar gas on a zeolite. (O.M.)

  17. Investigation of Gas Solid Fluidized Bed Dynamics with Non-Spherical Particles

    Energy Technology Data Exchange (ETDEWEB)

    Choudhuri, Ahsan [Univ. of Texas, El Paso, TX (United States). Dept. of Mechanical Engineering

    2013-06-30

    One of the largest challenges for 21st century is to fulfill global energy demand while also reducing detrimental impacts of energy generation and use on the environment. Gasification is a promising technology to meet the requirement of reduced emissions without compromising performance. Coal gasification is not an incinerating process; rather than burning coal completely a partial combustion takes place in the presence of steam and limited amounts of oxygen. In this controlled environment, a chemical reaction takes place to produce a mixture of clean synthetic gas. Gas-solid fluidized bed is one such type of gasification technology. During gasification, the mixing behavior of solid (coal) and gas and their flow patterns can be very complicated to understand. Many attempts have taken place in laboratory scale to understand bed hydrodynamics with spherical particles though in actual applications with coal, the particles are non-spherical. This issue drove the documented attempt presented here to investigate fluidized bed behavior using different ranges of non-spherical particles, as well as spherical. For this investigation, various parameters are controlled that included particle size, bed height, bed diameter and particle shape. Particles ranged from 355 µm to 1180 µm, bed diameter varied from 2 cm to 7 cm, two fluidized beds with diameters of 3.4 cm and 12.4 cm, for the spherical and non-spherical shaped particles that were taken into consideration. Pressure drop was measured with increasing superficial gas velocity. The velocity required in order to start to fluidize the particle is called the minimum fluidization velocity, which is one of the most important parameters to design and optimize within a gas-solid fluidized bed. This minimum fluidization velocity was monitored during investigation while observing variables factors and their effect on this velocity. From our investigation, it has been found that minimum fluidization velocity is independent of bed

  18. Greenhouse gas contribution of municipal solid waste collection: A case study in the city of Istanbul, Turkey.

    Science.gov (United States)

    Korkut, Nafiz E; Yaman, Cevat; Küçükağa, Yusuf; Jaunich, Megan K; Demir, İbrahim

    2018-02-01

    This article estimates greenhouse gas emissions and global warming factors resulting from collection of municipal solid waste to the transfer stations or landfills in Istanbul for the year of 2015. The aim of this study is to quantify and compare diesel fuel consumption and estimate the greenhouse gas emissions and global warming factors associated with municipal solid waste collection of the 39 districts of Istanbul. Each district's greenhouse gas emissions resulting from the provision and combustion of diesel fuel was estimated by considering the number of collection trips and distances to municipal solid waste facilities. The estimated greenhouse gases and global warming factors for the districts varied from 61.2 to 2759.1 t CO 2 -eq and from 4.60 to 15.20 kg CO 2 -eq t -1 , respectively. The total greenhouse gas emission was estimated as 46.4E3 t CO 2 -eq. Lastly, the collection data from the districts was used to parameterise a collection model that can be used to estimate fuel consumption associated with municipal solid waste collection. This mechanistic model can then be used to predict future fuel consumption and greenhouse gas emissions associated with municipal solid waste collection based on projected population, waste generation, and distance to transfer stations and landfills. The greenhouse gas emissions can be reduced by decreasing the trip numbers and trip distances, building more transfer stations around the city, and making sure that the collection trucks are full in each trip.

  19. Potential for a solids fire during an ITP waste tank deflagration and the impact on gas pressure

    International Nuclear Information System (INIS)

    Thomas, J.K.

    1993-07-01

    During the In-Tank Precipitation (ITP) process, solid deposits may form at the water-line on internal waste tank surfaces. These solids may be combustible due to the presence of tetraphenylborate compounds and hence there is a potential that a waste tank deflagration could ignite a solids fire. The work described in this report evaluates the potential for a waste tank deflagration to ignite a solids fire and the subsequent effect on gas pressure. Thermal analyses were performed using a one-dimensional conduction model, radiative heat flux values calculated with the Deflagration Pressure Analysis Code (DPAC), and effective deposit properties calculated from the component properties. It was shown that a solids fire could only be ignited by a waste tank deflagration for a limited range of cases. For the best-estimate mixtures, a solids fire could not be ignited prior to the time the peak gas pressure is reached and would not increase the peak pressure. For the upper-bound mixtures, the thickness of the solid layer which could be ignited is insufficient to increase the energy released by the deflagration by a significant amount. It was also shown that these conclusions are relatively insensitive to uncertainties related to deposit composition. Thus, the contribution from a solids fire to the gas pressure resulting from a waste tank deflagration may be neglected

  20. Numerical simulation of the gas-solid flow in a square circulating fluidized bed with secondary air injection

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhengyang [Harbin Institute of Technology, Harbin (China). Post-doctor Station of Civil Engineering; Harbin Institute of Technology, Harbin (China). Combustion Engineering Research Inst.; Sun, Shaozeng; Zhao, Ningbo; Wu, Shaohua [Harbin Institute of Technology, Harbin (China). Combustion Engineering Research Inst.; Tan, Yufei [Harbin Institute of Technology, Harbin (China). School of Municipal and Environmental Engineering

    2013-07-01

    The dynamic behavior of gas-solid flow in an experimental square circulating fluidized bed setup (0.25 m x 0.25 m x 6.07 m) is predicted with numerical simulation based on the theory of Euler-Euler gas-solid two-phase flow and the kinetic theory of granular flows. The simulation includes the operation cases with secondary injection and without air-staging. The pressure drop profile, local solids concentration and particle velocity was compared with experimental results. Both simulation and experimental results show that solids concentration increases significantly below the secondary air injection ports when air-staging is adopted. Furthermore, the flow asymmetry in the solid entrance region of the bed was investigated based on the particle concentration/velocity profile. The simulation results are in agreement with the experimental results qualitatively.

  1. Experimental study of single-electron loss by Ar{sup +} ions in rare-gas atoms

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, P.G. [Facultad de Ciencias, UNAM, Coyoacan (Mexico); Castillo, F. [Instituto de Ciencias Nucleares, UNAM, Coyoacan (Mexico); Martinez, H. [Centro de Ciencias Fisicas, UNAM, Cuernavaca, Morelos (Mexico)]. E-mail: hm@fis.unam.mx

    2001-04-28

    Absolute differential and total cross sections for single-electron loss were measured for Ar{sup +} ions on rare-gas atoms in the laboratory energy range of 1.5 to 5.0 keV. The electron loss cross sections for all the targets studied are found to be in the order of magnitude between 10{sup -19} and 10{sup -22} cm{sup 2}, and show a monotonically increasing behaviour as a function of the incident energy. The behaviour of the total single-electron loss cross sections with the atomic target number, Z{sub t}, shows different dependences as the collision energy increases. In all cases the present results display experimental evidence of saturation in the single-electron loss cross section as the atomic number of the target increases. (author)

  2. An ab initio study on four low-lying electronic potential energy curves for atomic cesium and rare gas pairs

    International Nuclear Information System (INIS)

    Kobayashi, Takanori; Yuki, Kenta; Matsuoka, Leo

    2016-01-01

    Using multireference configuration interaction (MRCI) calculations with single and double excitation levels, Davidson correction, and a spin-orbit (SO) effective core potential, we have developed a series of four low-lying electronic potential energy curves (PECs) for the pairs formed between a cesium atom (Cs) and a rare gas (Rg = He, Ne, Ar, Kr, and Xe). The results obtained at the MRCI level were compared with those generated at the SOCI level, which were recently reported by Blank et al. The shapes of the PECs were essentially the same when the same basis set was used. Based on this agreement, more precise PECs for Cs-Rg pairs were calculated using a larger basis set for Rg. (author)

  3. Oil and gas resources of the Cheat Mountain Further Planning Area (RARE II), Randolph County, West Virginia

    Science.gov (United States)

    Weed, E.G.

    1981-01-01

    The Wilderness Act (Public Law 88-577, September 3, 1964) and related acts require the U.S. Geological Survey and the U.S. Bureau of Mines to survey certain areas on Federal lands to determine their mineral resource potential. Results must be made available to the public and be submitted to the President and the Congress. This map presents an analysis of the oil and gas resources of the Cheat Mountain Further Planning Area in the Monongahela National Forest, Randolph County, West Virginia. The area was classified as a further planning area during the Second Roadless Area Review and Evaluation (RARE II) by the U.S. Forest Service, January 1979.

  4. Versatile 0.5 TW electron beam facility for power conditioning studies of large rare-gas/halide lasers

    International Nuclear Information System (INIS)

    Ramirez, J.J.

    1980-01-01

    Rare-gas/halide lasers which are being developed for Inertial Confinement Fusion will require large area, low impedance electron beam drivers. A wide range of electron beam parameters are being considered for future systems in an effort to optimize the overall system design. A number of power conditioning issues must be investigated in order to obtain a better understanding of the various trade-offs involved in making such optimizations. The RAYITO electron beam accelerator is being designed and built at Sandia National Laboratories and will be used for such investigations. It will be capable of operating in either a 2 or 4 ohm configuration at 1 MV, 50 ns or 0.8 MV, 200 ns. Design details for RAYITO are presented in this paper. Experiments planned for this facility are also discussed

  5. Calculated isotropic Raman spectra from interacting H2-rare-gas pairs

    International Nuclear Information System (INIS)

    Gustafsson, M; Głaz, W; Bancewicz, T; Godet, J-L; Maroulis, G; Haskapoulos, A

    2014-01-01

    We report on a theoretical study of the H 2 -He and H 2 -Ar pair trace-polarizability and the corresponding isotropic Raman spectra. The conventional quantum mechanical approach for calculations of interaction-induced spectra, which is based on an isotropic interaction potential, is employed. This is compared with a close-coupling approach, which allows for inclusion of the full, anisotropic potential. It is established that the anisotropy of the potential plays a minor role for these spectra. The computed isotropic collision-induced Raman intensity, which is due to dissimilar pairs in H 2 -He and H 2 -Ar gas mixtures, is comparable to the intensities due to similar pairs (H 2 -H 2 , He-He, and Ar-Ar), which have been studied previously

  6. Galatic and solar cosmic ray - produced rare gas isotopes in lunar fines

    International Nuclear Information System (INIS)

    Bhushan, B.N.; Rao, M.N.; Venkatesan, T.R.

    1979-01-01

    Lunar fines 10084, 14163 and 14148 from Apollo 11 and 14 missions as well as 24087 from Soviet Luna 24 mission have been studied for elemental and isotopic composition of He, Ne, Ar, Kr and Xe using milligram amounts by step-wise heating techniques. From these studies, the isotopic composition of solar wind has been determined and it is found to be in good agreement with the results reported by other workers. The experimental procedure adopted for studying these samples is described in brief. The use of a gas glass spectrometer for detecting the subtle galatic and solar cosmic ray xenon is explained. Data on the concentration and isotopic composition of selected isotopes of Xe and Ne in lunar fines is presented. (K.B.)

  7. High pressure operation of tubular solid oxide fuel cells and their intergration with gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Haynes, C.; Wepfer, W.J. [Georgia Institute of Technology, Atlanta, GA (United States)

    1996-12-31

    Fossil fuels continue to be used at a rate greater than that of their natural formation, and the current byproducts from their use are believed to have a detrimental effect on the environment (e.g. global warming). There is thus a significant impetus to have cleaner, more efficient fuel consumption alternatives. Recent progress has led to renewed vigor in the development of fuel cell technology, which has been shown to be capable of producing high efficiencies with relatively benign exhaust products. The tubular solid oxide fuel cell developed by Westinghouse Electric Corporation has shown significant promise. Modeling efforts have been and are underway to optimize and better understand this fuel cell technology. Thus far, the bulk of modeling efforts has been for operation at atmospheric pressure. There is now interest in developing high-efficiency integrated gas turbine/solid oxide fuel cell systems. Such operation of fuel cells would obviously occur at higher pressures. The fuel cells have been successfully modeled under high pressure operation and further investigated as integrated components of an open loop gas turbine cycle.

  8. Avalanches near a solid insulator in nitrogen gas at atmospheric pressure

    International Nuclear Information System (INIS)

    Mahajan, S.M.; Sudarshan, T.S.; Department of Electrical and Computer Engineering, University of South Carolina, Columbia, South Carolina 29208)

    1989-01-01

    The pulsed Townsend (PT) technique was used to record the growth of avalanches near a solid insulator in nitrogen gas at 0.1 MPa. Several other nonconventional techniques for releasing initiatory electrons at the cathode are discussed. In this paper, experimental results of avalanches initiated by illuminating a fast (0.6-ns) nitrogen laser onto the cathode triple junction are presented. Data were recorded with plexiglas, Teflon, high-density polyethylene, low-density polyethylene, Delrin, etc. Effect of surface condition, variation of the distance between insulator surface and the avalanche initiation region, and the effect of a large number of previous avalanches on the avalanche characteristics at a particular voltage were studied. The Townsend primary ionization coefficient, hereafter referred to as growth coefficient (α), and drift velocity (V/sub e/) were evaluated through the PT technique. Results indicate that the avalanche growth in the vicinity of a solid insulator is less than that in an identical plain gas gap. Existence of a nonuniform field as a result of surface charges on the insulator and/or field modifications due to the avalanche space charge are believed to be responsible for this behavior

  9. Multiple scattering of low energy rare gas ions: a comparison of experiment and computer simulation

    International Nuclear Information System (INIS)

    Heiland, W.; Taglauer, E.; Robinson, M.T.

    1976-01-01

    Some aspects of ion scattering below a few keV have been interpreted by multiple scattering. This can partly be simulated by chain or string models, where the single crystal surface is replaced by a chain of atoms. The computer program MARLOWE allows a simulation of solid-ion interaction, which is much closer to reality, e.g. the crystal is three-dimensional, includes lattice vibrations, electronic stopping power, different scattering potentials, etc. It is shown that the energy of the reflected ions as a function of the primary energy, lattice constant, impact angle and scattering angle can be understood within the string model. These results of the string model are confirmed by the MARLOWE calculations. For an interpretation of the measured intensities the simple string model is insufficient, whereas with MARLOWE reasonable agreement with experimental data may be achieved, if the thermal vibrations of the lattice atoms are taken into account. The experimental data include Ne + →Ni, Ne + →Ag and preliminary data on Ne + →W. The screening parameters of the scattering potentials are estimated for these ion-atom combinations. The results allow some conclusions about surface Debye temperatures. (Auth.)

  10. Primary Effusion Lymphoma without an Effusion: A Rare Case of Solid Extracavitary Variant of Primary Effusion Lymphoma in an HIV-Positive Patient

    Directory of Open Access Journals (Sweden)

    Hamza Hashmi

    2018-01-01

    Full Text Available Primary effusion lymphoma (PEL is a unique form of non-Hodgkin lymphoma, usually seen in severely immunocompromised, HIV-positive patients. PEL is related to human herpesvirus-8 (HHV-8 infection, and it usually presents as a lymphomatous body cavity effusion in the absence of a solid tumor mass. There have been very few case reports of HIV-positive patients with HHV-8-positive solid tissue lymphomas not associated with an effusion (a solid variant of PEL. In the absence of effusion, establishing an accurate diagnosis can be challenging, and a careful review of morphology, immunophenotype, and presence of HHV-8 is necessary to differentiate from other subtypes of non-Hodgkin lymphoma. Treatment involves intensive chemotherapy, and prognosis is usually poor. We present a rare case of a PEL variant in an HIV-positive patient who presented with extensive lymphadenopathy without any associated effusions.

  11. Contribution to the modelling of gas-solid reactions and reactors; Contribution a la modelisation des reactions et des reacteurs gaz-solide

    Energy Technology Data Exchange (ETDEWEB)

    Patisson, F

    2005-09-15

    Gas-solid reactions control a great number of major industrial processes involving matter transformation. This dissertation aims at showing that mathematical modelling is a useful tool for both understanding phenomena and optimising processes. First, the physical processes associated with a gas-solid reaction are presented in detail for a single particle, together with the corresponding available kinetic grain models. A second part is devoted to the modelling of multiparticle reactors. Different approaches, notably for coupling grain models and reactor models, are illustrated through various case studies: coal pyrolysis in a rotary kiln, production of uranium tetrafluoride in a moving bed furnace, on-grate incineration of municipal solid wastes, thermogravimetric apparatus, nuclear fuel making, steel-making electric arc furnace. (author)

  12. Determination of volatile compounds in grape distillates by solid-phase extraction and gas chromatography.

    Science.gov (United States)

    Lukić, Igor; Banović, Mara; Persurić, Dordano; Radeka, Sanja; Sladonja, Barbara

    2006-01-06

    Solid-phase extraction (SPE) procedure on octadecylsilica (C18) was developed for accumulation of volatile compounds from grape distillates. The procedure was optimised for final analysis by capillary gas chromatography. At mass concentrations in model solutions ranging from 0.1 to 50 mg/l solid-phase extraction recoveries of all analytes ranged from 69% for 2-phenylethanol to 102% for capric acid, with RSD values from 2 to 9%. SPE recoveries of internal standards to be added in the sample solution prior to extraction, higher alcohols 2-ethyl-1-hexanol and 1-undecanol, were 97 and 93%, respectively, with RSD values of 3%. Detection limits of analyzed compounds in model solutions ranged from 0.011 mg/l for isoamyl acetate to 0.037 mg/l for caproic acid. Method efficiency was tested in relation to acetic acid content, volume fraction of ethanol and possible matrix effects. A significant influence of matrix on SPE efficiency for geraniol, cis-2-hexen-1-ol and cis-3-hexen-1-ol was detected. For the same reason, 2-phenylethanol could not be determined by developed SPE method in samples of grape distillates. The developed solid-phase extraction method was successfully applied to determine the differences in volatile compound content in different grape distillates produced by the distillation of crushed, pressed and fermented grapes.

  13. Solids precipitation in crude oils, gas-to-liquids and their blends

    Science.gov (United States)

    Ramanathan, Karthik

    Gas-to-liquids (GTL) liquids are obtained from syngas by the Fischer-Tropsch synthesis. The blending of GTL liquids produced from natural gas/coal reserves and crude oils is a possibility in the near future for multiple reasons. Solids precipitation is a major problem in pipelines and refineries leading to significant additional operating costs. The effect of the addition of a paraffinic GTL liquid to crude oils on solids precipitation was investigated in this study. A Fourier transform infrared (FT-IR) spectroscopic technique was used to obtain solid-liquid equilibria (SLE) data for the various samples. The SLE of multiple systems of model oils composed of n-alkanes was investigated preliminarily. Blends of a model oil simulating a GTL liquid composition and a crude oil showed that the wax precipitation temperature (WPT) decreased upon blending. Three crude oils from different geographic regions (Alaskan North Slope, Colorado and Venezuela) and a laboratory-produced GTL liquid were used in the preparation of blends with five different concentrations of the GTL liquid. The wax precipitation temperatures of the blends were found to decrease with the increasing addition of the GTL liquid for all the oils. This effect was attributed to the solvent effect of the low molecular weight-paraffinic GTL liquid on the crude oils. The weight percent solid precipitated that was estimated as a function of temperature did not show a uniform trend for the set of crude oils. The asphaltene onset studies done on the blends with near-infrared spectroscopy indicated that the addition of GTL liquid could have a stabilizing effect on the asphaltenes in some oils. Analytical techniques such as distillation, solvent separation, HPLC, GC, and GPC were used to obtain detailed composition data on the samples. Two sets of compositional data with 49 and 86 pseudo-components were used to describe the three crude oils used in the blending work. The wax precipitation was calculated using a

  14. Carbon-14 immobilization via the CO2-Ba(OH)2 hydrate gas-solid reaction

    International Nuclear Information System (INIS)

    Haag, G.L.

    1980-01-01

    Although no restrictions have been placed on the release of carbon-14, it has been identified as a potential health hazard due to the ease in which it may be assimilated into the biosphere. The intent of the Carbon-14 Immobilization Program, funded through the Airborne Waste Program Management Office, is to develop and demonstrate a novel process for restricting off-gas releases of carbon-14 from various nuclear facilities. The process utilizes the CO 2 -Ba(OH) 2 hydrate gas-solid reaction to directly remove and immobilize carbon-14. The reaction product, BaCO 3 , possesses both the thermal and chemical stability desired for long-term waste disposal. The process is capable of providing decontamination factors in excess of 1000 and reactant utilization of greater than 99% in the treatment of high volumetric, airlike (330 ppM CO 2 ) gas streams. For the treatment of an air-based off-gas stream, the use of packed beds of Ba(OH) 2 .8H 2 O flakes to remove CO 2 has been demonstrated. However, the operating conditions must be maintained between certain upper and lower limits with respect to the partial pressure of water. If the water vapor pressure in the gas is less than the dissociation vapor pressure of Ba(OH) 2 .8H 2 O, the bed will deactivate. If the vapor pressure is considerably greater, pressure drop problems will increase with increasing humidity as the particles curl and degrade. Results have indicated that when operated in the proper regime, the bulk of the increase in pressure drop results from the conversion of Ba(OH) 2 .8H 2 O to BaCO 3 and not from the hydration of the commercial Ba(OH) 2 .8H 2 O (i.e. Ba(OH) 2 .7.50H 2 O) to Ba(OH) 2 .8H 2 O

  15. Thermal-Flow Code for Modeling Gas Dynamics and Heat Transfer in Space Shuttle Solid Rocket Motor Joints

    Science.gov (United States)

    Wang, Qunzhen; Mathias, Edward C.; Heman, Joe R.; Smith, Cory W.

    2000-01-01

    A new, thermal-flow simulation code, called SFLOW. has been developed to model the gas dynamics, heat transfer, as well as O-ring and flow path erosion inside the space shuttle solid rocket motor joints by combining SINDA/Glo, a commercial thermal analyzer. and SHARPO, a general-purpose CFD code developed at Thiokol Propulsion. SHARP was modified so that friction, heat transfer, mass addition, as well as minor losses in one-dimensional flow can be taken into account. The pressure, temperature and velocity of the combustion gas in the leak paths are calculated in SHARP by solving the time-dependent Navier-Stokes equations while the heat conduction in the solid is modeled by SINDA/G. The two codes are coupled by the heat flux at the solid-gas interface. A few test cases are presented and the results from SFLOW agree very well with the exact solutions or experimental data. These cases include Fanno flow where friction is important, Rayleigh flow where heat transfer between gas and solid is important, flow with mass addition due to the erosion of the solid wall, a transient volume venting process, as well as some transient one-dimensional flows with analytical solutions. In addition, SFLOW is applied to model the RSRM nozzle joint 4 subscale hot-flow tests and the predicted pressures, temperatures (both gas and solid), and O-ring erosions agree well with the experimental data. It was also found that the heat transfer between gas and solid has a major effect on the pressures and temperatures of the fill bottles in the RSRM nozzle joint 4 configuration No. 8 test.

  16. Structure and UV-induced photochemistry of 2-furaldehyde dimethylhydrazone isolated in rare gas matrices

    Science.gov (United States)

    Araujo-Andrade, C.; Giuliano, B. M.; Gómez-Zavaglia, A.; Fausto, R.

    2012-11-01

    In this work, a combined matrix isolation FTIR and theoretical DFT(B3LYP)/6-311++G(d,p) study of 2-furaldehyde dimethylhydrazone (2FDH) was performed. According to calculations, two E and two Z conformers exist, the E forms having considerably lower energy than the Z forms. The absence of relevant sterical hindrance between the two substituents around the Cdbnd N bond (dimethylamino and 2-furyl) in the E structures and an extended π-p electron delocalization in the hydrazone moiety determines the higher stability of these species relatively to the Z structures. In the lowest energy form (E-AG) the O-C-Cdbnd N and Cdbnd N-N-Lp (Lp = lone electron pair of amine nitrogen atom) dihedral angles are predicted by the calculations to be -177.2° and 93.7°, respectively. The weak (Ndbnd C)-H⋯O hydrogen bond type interaction (H⋯O distance: 252.2 pm) in form E-AG, together with the absence in this form of the destabilizing interaction between the lone electron pairs of the oxygen and nitrogen atoms existing in E-SG, explains its lower energy in comparison with this latter form. Both E-AG and E-SG conformers could be trapped from room temperature gas phase in low temperature argon and xenon matrices. The high E-SG → E-AG energy barrier (>25 kJ mol-1) explains that, upon increasing the temperature of the matrices no conformational isomerization could be observed. After irradiation of 2FDH with UV-light at λ > 328 and λ > 234 nm, two different photochemistries were observed. Irradiation at lower energy (λ > 328 nm) induced the E-AG → E-SG isomerization. Further irradiation at higher energy (λ > 234 nm) led to a quick consumption of 2FDH and production of furan and dimethylisocyanide.

  17. Conceptual design of an angular multiplexed rare-gas-halide laser-fusion driver. Final technical report, 1 August 1979-31 May 1980

    International Nuclear Information System (INIS)

    Parks, J.H.

    1980-11-01

    A conceptual definition for angular multiplexed rare gas halide drivers was formulated and several design examples analyzed. Angular multiplexed rare gas-halide lasers, in particular the KrF* laser, can be designed to meet ICF requirements. These lasers are scalable, emit at short wavelengths (KrF* 250 nm), and through the use of optical angular multiplexing, produce the required high energy (approx. 1 to 5 MJ) in a short pulse (approx. 10 nsec) with projected overall efficiency in the range of 5 to 7%

  18. Electrical and optical properties of thin indium tin oxide films produced by pulsed laser ablation in oxygen or rare gas atmospheres

    DEFF Research Database (Denmark)

    Thestrup, B.; Schou, Jørgen; Nordskov, A.

    1999-01-01

    Films of indium tin oxide (ITO) have been produced in different background gases by pulsed laser deposition (PLD). The Films deposited in rare gas atmospheres on room temperature substrates were metallic, electrically conductive, but had poor transmission of visible light. For substrate temperatu......Films of indium tin oxide (ITO) have been produced in different background gases by pulsed laser deposition (PLD). The Films deposited in rare gas atmospheres on room temperature substrates were metallic, electrically conductive, but had poor transmission of visible light. For substrate...

  19. An experimental device for measurement of gas permeation in solid matrices

    International Nuclear Information System (INIS)

    De Salve, M.; Mazzi, E.; Zucchetti, M.

    1996-01-01

    The inventory in and the permeation through fusion reactor structures of hydrogen and its isotopes play an important role in the machine operation, evolution of material properties, and safety. An experimental and research activity for the determination of permeability (and derived parameters) of gases in solid matrices is described. It uses a gas permeation method, that basically consists in the measure of the time evolution of the gas pressure in a chamber in which vacuum has been previously made (downstream volume). This chamber is separated from another one, full of the gas in exam (upstream volume), by means of a membrane of the material under study. The experimental installation is described. The first stage of the experimental activity has dealt with the set-up of the device, the volume calibration, and the definition of the parameters range for which the installation can give reliable measurements. The subsequent stage of the activity has consisted in the measurement of the permeability, and then of the diffusion coefficient, of nitrogen in some materials at room temperature. Concurrently with the experimental activity, a model has been set-up and implemented in a computer code: this code permits to evaluate the time evolution of the pressure in the downstream chamber. With this code, using the measured parameters, the time evolution of the pressure experimentally measured has been satisfactorily reproduced. (author)

  20. Modelling greenhouse gas emissions for municipal solid waste management strategies in Ottawa, Ontario, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Mohareb, Adrian K. [Technology Early Action Measures (TEAM) Office, 55 Murray Street, Suite 230, Ottawa, ON (Canada); Warith, Mostafa A.; Diaz, Rodrigo [Department of Civil Engineering, Ryerson University, 350 Victoria Street, Toronto, ON (Canada)

    2008-09-15

    Human-induced climate change, through the emission of greenhouse gases, may result in a significant negative impact on Earth. Canada is one of the largest per capita emitters of greenhouse gas, generating 720 megatonnes (Mt) carbon dioxide equivalents (CO{sub 2}e), or per capita emissions of 23.2 t CO{sub 2}e. The solid waste sector in Canada was directly responsible for 25 Mt CO{sub 2}e in 2001, of which 23 Mt CO{sub 2}e were produced by landfill gas (LFG). A modelling exercise was undertaken to determine greenhouse gas (GHG) emissions from the waste sector using the waste disposal, recycling, and composting data from Ottawa, Ontario, Canada for the year 2003, as well as the results of an audit of residential units performed in the same year. This evaluation determined that, among the options examined, waste incineration, further source separation of recyclables, and anaerobic digestion of an organic wastes have the greatest benefits for reducing GHG emissions in the City of Ottawa's waste sector. Challenges surrounding the installation of incineration facilities in Canada suggest that improved diversion of recyclable materials and anaerobic digestion of organic materials are the optimal options for the City of Ottawa to pursue. (author)

  1. Thermodynamic analysis of solid oxide fuel cell gas turbine systems operating with various biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Patel, H.C.; Woudstra, T.; Aravind, P.V. [Process and Energy Laboratory, Delft University of Technology, Section Energy Technology, Leeghwaterstraat 44, 2628 CA Delft (Netherlands)

    2012-12-15

    Solid oxide fuel cell-gas turbine (SOFC-GT) systems provide a thermodynamically high efficiency alternative for power generation from biofuels. In this study biofuels namely methane, ethanol, methanol, hydrogen, and ammonia are evaluated exergetically with respect to their performance at system level and in system components like heat exchangers, fuel cell, gas turbine, combustor, compressor, and the stack. Further, the fuel cell losses are investigated in detail with respect to their dependence on operating parameters such as fuel utilization, Nernst voltage, etc. as well as fuel specific parameters like heat effects. It is found that the heat effects play a major role in setting up the flows in the system and hence, power levels attained in individual components. The per pass fuel utilization dictates the efficiency of the fuel cell itself, but the system efficiency is not entirely dependent on fuel cell efficiency alone, but depends on the split between the fuel cell and gas turbine powers which in turn depends highly on the nature of the fuel and its chemistry. Counter intuitively it is found that with recycle, the fuel cell efficiency of methane is less than that of hydrogen but the system efficiency of methane is higher. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Universal stability curve for pattern formation in pulsed gas-solid fluidized beds of sandlike particles

    Science.gov (United States)

    de Martín, Lilian; Ottevanger, Coen; van Ommen, J. Ruud; Coppens, Marc-Olivier

    2018-03-01

    A granular layer can form regular patterns, such as squares, stripes, and hexagons, when it is fluidized with a pulsating gas flow. These structures are reminiscent of the well-known patterns found in granular layers excited through vibration, but, contrarily to them, they have been hardly explored since they were first discovered. In this work, we investigate experimentally the conditions leading to pattern formation in pulsed fluidized beds and the dimensionless numbers governing the phenomenon. We show that the onset to the instability is universal for Geldart B (sandlike) particles and governed by the hydrodynamical parameters Γ =ua/(utϕ ¯) and f /fn , where ua and f are the amplitude and frequency of the gas velocity, respectively, ut is the terminal velocity of the particles, ϕ ¯ is the average solids fraction, and fn is the natural frequency of the bed. These findings suggest that patterns emerge as a result of a parametric resonance between the kinematic waves originating from the oscillating gas flow and the bulk dynamics. Particle friction plays virtually no role in the onset to pattern formation, but it is fundamental for pattern selection and stabilization.

  3. Hazardous gas production by alpha particles in solid organic transuranic waste matrices. 1998 annual progress report

    International Nuclear Information System (INIS)

    LaVerne, J.A.

    1998-01-01

    'This project uses fundamental radiation chemical techniques to elucidate the basic processes occurring in the heavy-ion radiolysis of solid hydrocarbon matrices such as polymers and organic resins that are associated with many of the transuranic waste deposits or the transportation of these radionuclides. The environmental management of mixed waste containing transuranic radionuclides is difficult because these nuclides are alpha particle emitters and the energy deposited by the alpha particles causes chemical transformations in the matrices accompanying the waste. Most radiolysis programs focus on conventional radiation such as gamma rays, but the chemical changes induced by alpha particles and other heavy ions are typically very different and product yields can vary by more than an order of magnitude. The objective of this research is to measure the production of gases, especially molecular hydrogen, produced in the proton, helium ion, and carbon ion radiolysis of selected solid organic matrices in order to obtain fundamental mechanistic information on the radiolytic decomposition of these materials. This knowledge can also be used to directly give reasonable estimates of explosive or flammability hazards in the storage or transport of transuranic wastes in order to enhance the safety of DOE sites. This report summarizes the work after eight months of a three-year project on determining the production of hazardous gases in transuranic waste. The first stage of the project was to design and build an assembly to irradiate solid organic matrices using accelerated ion beams. It is necessary to measure absolute radiolytic yields, and simulate some of the conditions found in the field. A window assembly was constructed allowing the beam to pass consecutively through a collimator, a vacuum exit window and into the solid sample. The beam is stopped in the sample and the entire end of the assembly is a Faraday cup. Integration of the collected current, in conjunction

  4. Fixing arsenic contained in a gas phase using solid hematite; Fijacion de arsenico en fase gas con hematita solida

    Energy Technology Data Exchange (ETDEWEB)

    Balladares, E.; Gonzalez, A.; Rarra, R.; Sanchez, M.

    2004-07-01

    Feasibility to obtain ferric arsenate starting from arsenic containing gas in contact with Fe{sub 3}O{sub 3} has been studied. Thermodynamic stability of the system Fe-As-O was analysed in order to verify conditions to form Fe{sub x}As{sub y}O{sub z} type compounds. Experiments were made using a hematite sample suspended in a thermogravimetric device. As{sub 4}O{sub 6} was generated starting from solid As{sub 2}O{sub 3} which was circulating through the iron oxide. Final samples were analysed chemically and by means of DRX, verifying the formation of FeAsO{sub 4}, FeAsO{sub 4}.2h{sub 2}O and FeAsO{sub 4}.(H{sub 2}O){sub 2} in small quantities. Tests in porous bed and pellets were carried out, studying the effect of: porosity, temperature and oxygen potential. The largest conversion obtained was 10% at 800 degree centigree, pO{sub 2}=50% and porosity=0.883. (Author) 9 refs.

  5. Glass bottle sampling solid phase microextraction gas chromatography mass spectrometry for breath analysis of drug metabolites.

    Science.gov (United States)

    Lu, Yan; Niu, Wenqi; Zou, Xue; Shen, Chengyin; Xia, Lei; Huang, Chaoqun; Wang, Hongzhi; Jiang, Haihe; Chu, Yannan

    2017-05-05

    Breath analysis is a non-invasive approach which may be applied to disease diagnosis and pharmacokinetic study. In the case of offline analysis, the exhaled gas needs to be collected and the sampling bag is often used as the storage vessel. However, the sampling bag usually releases some extra compounds, which may interfere with the result of the breath test. In this study, a novel breath sampling glass bottle was developed with a syringe needle sampling port for solid phase microextraction (SPME). Such a glass bottle scarcely liberates compounds and can be used to collect exhaled gas for ensuing analysis by gas chromatography-mass spectrometry (GC-MS). The glass bottle sampling SPME-GC-MS analysis was carried out to investigate the breath metabolites of myrtol, a multicompound drug normally used in the treatment of bronchitis and sinusitis. Four compounds, α-pinene, 2,3-dehydro-1,8-cineole, d-limonene and 1,8-cineole were found in the exhaled breath of all eight volunteers who had taken the myrtol. While for other ten subjects who had not used the myrtol, these compounds were undetectable. In the SPME-GC-MS analysis of the headspace of myrtol, three compounds were detected including α-pinene, d-limonene and 1,8-cineole. Comparing the results of breath and headspace analysis, it indicates that 2,3-dehydro-1,8-cineole in the breath is the metabolite of 1,8-cineole. It is the first time that this metabolite was identified in human breath. The study demonstrates that the glass bottle sampling SPME-GC-MS method is applicable to exhaled gas analysis including breath metabolites investigation of drugs like myrtol. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Modeling the Gas Dynamics Environment in a Subscale Solid Rocket Test Motor

    Science.gov (United States)

    Eaton, Andrew M.; Ewing, Mark E.; Bailey, Kirk M.; McCool, Alex (Technical Monitor)

    2001-01-01

    Subscale test motors are often used for the evaluation of solid rocket motor component materials such as internal insulation. These motors are useful for characterizing insulation performance behavior, screening insulation material candidates and obtaining material thermal and ablative property design data. One of the primary challenges associated with using subscale motors however, is the uncertainty involved when extrapolating the results to full-scale motor conditions. These uncertainties are related to differences in such phenomena as turbulent flow behavior and boundary layer development, propellant particle interactions with the wall, insulation off-gas mixing and thermochemical reactions with the bulk flow, radiation levels, material response to the local environment, and other anomalous flow conditions. In addition to the need for better understanding of physical mechanisms, there is also a need to better understand how to best simulate these phenomena using numerical modeling approaches such as computational fluid dynamics (CFD). To better understand and model interactions between major phenomena in a subscale test motor, a numerical study of the internal flow environment of a representative motor was performed. Simulation of the environment included not only gas dynamics, but two-phase flow modeling of entrained alumina particles like those found in an aluminized propellant, and offgassing from wall surfaces similar to an ablating insulation material. This work represents a starting point for establishing the internal environment of a subscale test motor using comprehensive modeling techniques, and lays the groundwork for improving the understanding of the applicability of subscale test data to full-scale motors. It was found that grid resolution, and inclusion of phenomena in addition to gas dynamics, such as two-phase and multi-component gas composition are all important factors that can effect the overall flow field predictions.

  7. ESR of the triplet molecules CCO and CNN in rare-gas matrices; isotope and matrix effects

    International Nuclear Information System (INIS)

    Smith, G.R.; Weltner, W. Jr.

    1975-01-01

    CCO and CNN, with isotopic substitution of 13 C, 18 O, and 15 N, were prepared by the reaction of C atoms with CO or N 2 and trapped in various matrices at 4 degreeK. ESR spectra of both 3 Σ molecules yielded hyperfine splittings, g values, and zero-field splittings. In solid neon, these parameters for C/sub alpha/C/sub beta/O, assuming g/sub parallel/=g/sube/, were g/sub perpendicular/=2.0029(4), D=0.7392(4) cm -1 , vertical-barA/sub perpendicular/(C/sub alpha/) vertical-bar = 57(3) MHz, vertical-barA/sub parallel/(C/sub alpha/) vertical-bar = 17(3) MHz, vertical-barA/sub perpendicular/(C/sub beta/) vertical-bar = 26(3) MHz, vertical-barA/sub parallel/(C/sub beta/) vertical-bar = 32(3) MHz. Similar but less extensive data were obtained for CN/sub alpha/N/sub beta/ where in solid neon, assuming g/sub parallel/ =g/sub perpendicular/=g/sube/, D = 1.1590(5) cm -1 , vertical-barA/sub perpendicular/( 14 N/sub alpha/) vertical-bar = 35(5), vertical-barA/sub perpendicular/( 14 N/sub beta/) vertical-bar = 19(5), and vertical-barA/sub perpendicular/( 13 C) vertical-bar = 50(5) MHz. D values for isotopic molecules 12 C 12 C 16 O, 13 C 12 C 18 O, etc., varied by small but significant amounts (up to about 0.001 cm -1 ) in Ne and in Ar matrices. These variations could be approximately accounted for by assuming torsional oscillation in the solid. This was supported by a temperature variation study. The observed decrease of D/sub gas/ = 0.772 cm -1 for C 2 O in matrices, particularly large in Kr and Xe, is attributed partially to motional averaging and partially to matrix perturbations of molecular electronic properties. Theory was applied to qualitatively account for the changes in spin--spin, D/sub SS/, and spin--orbit, D/sub SO/, contributions to the zfs of the molecule in the solids

  8. Direct gas-solid carbonation kinetics of steel slag and the contribution to in situ sequestration of flue gas CO(2) in steel-making plants.

    Science.gov (United States)

    Tian, Sicong; Jiang, Jianguo; Chen, Xuejing; Yan, Feng; Li, Kaimin

    2013-12-01

    Direct gas-solid carbonation of steel slag under various operational conditions was investigated to determine the sequestration of the flue gas CO2 . X-ray diffraction analysis of steel slag revealed the existence of portlandite, which provided a maximum theoretical CO2 sequestration potential of 159.4 kg CO 2 tslag (-1) as calculated by the reference intensity ratio method. The carbonation reaction occurred through a fast kinetically controlled stage with an activation energy of 21.29 kJ mol(-1) , followed by 10(3) orders of magnitude slower diffusion-controlled stage with an activation energy of 49.54 kJ mol(-1) , which could be represented by a first-order reaction kinetic equation and the Ginstling equation, respectively. Temperature, CO2 concentration, and the presence of SO2 impacted on the carbonation conversion of steel slag through their direct and definite influence on the rate constants. Temperature was the most important factor influencing the direct gas-solid carbonation of steel slag in terms of both the carbonation conversion and reaction rate. CO2 concentration had a definite influence on the carbonation rate during the kinetically controlled stage, and the presence of SO2 at typical flue gas concentrations enhanced the direct gas-solid carbonation of steel slag. Carbonation conversions between 49.5 % and 55.5 % were achieved in a typical flue gas at 600 °C, with the maximum CO2 sequestration amount generating 88.5 kg CO 2 tslag (-1) . Direct gas-solid carbonation of steel slag showed a rapid CO2 sequestration rate, high CO2 sequestration amounts, low raw-material costs, and a large potential for waste heat utilization, which is promising for in situ carbon capture and sequestration in the steel industry. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Using heavy atom rare gas matrix to control the reactivity of 4-methoxybenzaldehyde: A comparison with benzaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Kus, Nihal [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Department of Physics, Anadolu University, 26470 Eskisehir (Turkey); Sharma, Archna; Reva, Igor; Fausto, Rui [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Lapinski, Leszek [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland)

    2012-04-14

    Different patterns of photochemical behavior were observed for 4-methoxybenzaldehyde (p-anisaldehyde) isolated in xenon and in argon matrices. Monomers of the compound isolated in solid Xe decarbonylate upon middle ultraviolet irradiation, yielding methoxybenzene (anisole), and CO. On the other hand, p-anisaldehyde isolated in an Ar matrix and subjected to identical irradiation, predominantly isomerizes to the closed-ring isomeric ketene (4-methoxycyclohexa-2,4-dien-1-ylidene) methanone. Experimental detection of a closed-ring ketene photoproduct, generated from an aromatic aldehyde, constitutes a rare observation. The difference between the patterns of photochemical transformations of p-anisaldehyde isolated in argon and xenon environments can be attributed to the external heavy-atom effect, where xenon enhances the rate of intersystem crossing from the singlet to the triplet manifold in which decarbonylation (via p-methoxybenzoyl radical) takes place. The parent compound, benzaldehyde, decarbonylates (to benzene + CO) when subjected to middle ultraviolet irradiation in both argon and xenon matrices. This demonstrates the role of the methoxy p-anisaldehyde substituent in activation of the reaction channel leading to the formation of the ketene photoproduct.

  10. Heat Transfer Analysis and Modification of Thermal Probe for Gas-Solid Measurement

    Directory of Open Access Journals (Sweden)

    Hong Zhang

    2016-01-01

    Full Text Available The presented work aims to measure the gas-solid two-phase mass flow-rate in pneumatic conveyor, and a novel modified thermal probe is applied. A new analysis of the local heat transfer coefficients of thermal probe is presented, while traditional investigations focus on global coefficients. Thermal simulations are performed in Fluent 6.2 and temperature distributions of the probe are presented. The results indicate that the probe has obviously stable and unstable heat transfer areas. Based on understanding of probe characteristics, a modified probe structure is designed, which makes the probe output signal more stable and widens the measuring range. The experiments are carried out in a special designed laboratory scale pneumatic conveyor, and the modified probe shows an unambiguous improvement of the performance compared with the traditional one.

  11. Thermal and Hydrothermal Treatment of Silica Gels as Solid Stationary Phases in Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Ashraf Yehia El-Naggar

    2013-01-01

    Full Text Available Silica gel was prepared and treated thermally and hydrothermally and was characterized as solid stationary phase in gas chromatography. The characteristics have been evaluated in terms of polarity, selectivity, and separation efficiencies. These parameters were used to assess the outer silica surface contributions and the degree of surface deactivation brought about by different treatment techniques. The parent silica elutes the paraffinic hydrocarbons with high efficiency of separation and elutes aromatic hydrocarbons with nearly good separation and has bad separation of alcohols. The calcined silica at 500°C and 1000°C has a pronounced effect on the separation of aromatic hydrocarbons compared with the parent silica and hydrothermal treatment of silica. With respect to alcohols separation, the obtained bad separations using treated and untreated silica reflect the little effect of the thermal and hydrothermal treatment on the silica surface deactivation.

  12. Headspace Solid Phase Micro Extraction Gas Chromatographic Determination of Fenthion in Human Serum

    Directory of Open Access Journals (Sweden)

    Kyriaki Machera

    2008-05-01

    Full Text Available A simple and effective analytical procedure was developed for the determination of fenthion residues in human serum samples. The sample treatment was performed using the headspace solid-phase micro extraction with polyacrylate fiber, which has the advantage to require low amount of serum (1 mL without tedious pre-treatment. The quantification of fenthion was carried out by gas chromatography-mass spectrometry and the recoveries ranged from 79 to 104% at two spiking levels for 6 replicates. Detection and quantification limits were calculated as 1.51 and 4.54 ng/mL of serum respectively. Two fenthion metabolites − fenoxon and fenthion–sulfoxide − were also identified.

  13. The international symposium on 'chemical engineering of gas-liquid-solid catalyst reactions'

    Energy Technology Data Exchange (ETDEWEB)

    Hammer, H

    1978-06-01

    A report on the International Symposium on ''Chemical Engineering of Gas-Liquid-Solid Catalyst Reactions'', sponsored by the University of Liege (3/2-3/78), covers papers on the hydrodynamics, modeling and simulation, operating behavior, and chemical kinetics of trickle-bed reactors; scale-up of a trickle-bed reactor for hydrotreating Kuwait vacuum distillate; experimental results obtained in trickle-bed reactors for hydroprocessing atmospheric residua, hydrogenation of methylstyrene, hydrogenation of butanone, and hydrodemetallization of petroleum residua; advantages and disadvantages of various three-phase reactor types (e.g., for the liquid-phase hydrogenation of carbon monoxide to benzene, SNG, or methanol) and hydrodynamics, mass and heat transfer, and modeling of bubble columns with suspended catalysts (slurry reactors), and their applications (e.g., in SNG and fermentation processes).

  14. Time series analysis of pressure fluctuation in gas-solid fluidized beds

    Directory of Open Access Journals (Sweden)

    C. Alberto S. Felipe

    2004-09-01

    Full Text Available The purpose of the present work was to study the differentiation of states of typical fluidization (single bubble, multiple bubble and slugging in a gas-solid fluidized bed, using spectral analysis of pressure fluctuation time series. The effects of the method of measuring (differential and absolute pressure fluctuations and the axial position of the probes in the fluidization column on the identification of each of the regimes studied were evaluated. Fast Fourier Transform (FFT was the mathematic tool used to analysing the data of pressure fluctuations, which expresses the behavior of a time series in the frequency domain. Results indicated that the plenum chamber was a place for reliable measurement and that care should be taken in measurement in the dense phase. The method allowed fluid dynamic regimes to be differentiated by their dominant frequency characteristics.

  15. Electrostatic sensors applied to the measurement of electric charge transfer in gas-solids pipelines

    International Nuclear Information System (INIS)

    Woodhead, S R; Denham, J C; Armour-Chelu, D I

    2005-01-01

    This paper describes the development of a number of electric charge sensors. The sensors have been developed specifically to investigate triboelectric charge transfer which takes place between particles and the pipeline wall, when powdered materials are conveyed through a pipeline using air. A number of industrial applications exist for such gas-solids pipelines, including pneumatic conveyors, vacuum cleaners and dust extraction systems. The build-up of electric charge on pipelines and powdered materials can lead to electrostatic discharge and so is of interest from a safety viewpoint. The charging of powders can also adversely affect their mechanical handling characteristics and so is of interest to handling equipment engineers. The paper presents the design of the sensors, the design of the electric charge test rig and electric charge measurement test results

  16. Harsh-Environment Solid-State Gamma Detector for Down-hole Gas and Oil Exploration

    International Nuclear Information System (INIS)

    Peter Sandvik; Stanislav Soloviev; Emad Andarawis; Ho-Young Cha; Jim Rose; Kevin Durocher; Robert Lyons; Bob Pieciuk; Jim Williams; David O'Connor

    2007-01-01

    The goal of this program was to develop a revolutionary solid-state gamma-ray detector suitable for use in down-hole gas and oil exploration. This advanced detector would employ wide-bandgap semiconductor technology to extend the gamma sensor's temperature capability up to 200 C as well as extended reliability, which significantly exceeds current designs based on photomultiplier tubes. In Phase II, project tasks were focused on optimization of the final APD design, growing and characterizing the full scintillator crystals of the selected composition, arranging the APD device packaging, developing the needed optical coupling between scintillator and APD, and characterizing the combined elements as a full detector system preparing for commercialization. What follows is a summary report from the second 18-month phase of this program

  17. Harsh-Environment Solid-State Gamma Detector for Down-hole Gas and Oil Exploration

    Energy Technology Data Exchange (ETDEWEB)

    Peter Sandvik; Stanislav Soloviev; Emad Andarawis; Ho-Young Cha; Jim Rose; Kevin Durocher; Robert Lyons; Bob Pieciuk; Jim Williams; David O' Connor

    2007-08-10

    The goal of this program was to develop a revolutionary solid-state gamma-ray detector suitable for use in down-hole gas and oil exploration. This advanced detector would employ wide-bandgap semiconductor technology to extend the gamma sensor's temperature capability up to 200 C as well as extended reliability, which significantly exceeds current designs based on photomultiplier tubes. In Phase II, project tasks were focused on optimization of the final APD design, growing and characterizing the full scintillator crystals of the selected composition, arranging the APD device packaging, developing the needed optical coupling between scintillator and APD, and characterizing the combined elements as a full detector system preparing for commercialization. What follows is a summary report from the second 18-month phase of this program.

  18. Contribution to the use of a solid moderator gas reactor, for naval propulsion

    International Nuclear Information System (INIS)

    Pheline, J.; Gautier, A.

    1960-01-01

    In this contribution, the authors discuss works performed in France for the development of nuclear propulsion in merchant ships, notably for an oil tanker of 50.000 tons with 17 knot speed, i.e. a 20.000 Hp engine with an energy produced by a 60 MW gas reactor with a solid moderator and comprising 400 channels loaded with uranium oxide enriched ay 2.8 per cent and sheathed with a refractory alloy. The authors discuss the possible materials for the moderator, the heat transfer medium, the sheath, the fuel and the structures, and report technological studies (mechanical tests, irradiation tests) performed to investigate material properties and their behaviour in operation conditions. They report tests performed to investigate core structure characteristics with respect to neutrons. They finally briefly present a prototype

  19. Headspace solid-phase microextraction procedures for gas chromatographic analysis of biological fluids and materials.

    Science.gov (United States)

    Mills, G A; Walker, V

    2000-12-01

    Solid-phase microextraction (SPME) is a new solventless sample preparation technique that is finding wide usage. This review provides updated information on headspace SPME with gas chromatographic separation for the extraction and measurement of volatile and semivolatile analytes in biological fluids and materials. Firstly the background to the technique is given in terms of apparatus, fibres used, extraction conditions and derivatisation procedures. Then the different matrices, urine, blood, faeces, breast milk, hair, breath and saliva are considered separately. For each, methods appropriate for the analysis of drugs and metabolites, solvents and chemicals, anaesthetics, pesticides, organometallics and endogenous compounds are reviewed and the main experimental conditions outlined with specific examples. Then finally, the future potential of SPME for the analysis of biological samples in terms of the development of new devices and fibre chemistries and its coupling with high-performance liquid chromatography is discussed.

  20. Organic compound emissions from a landfarm used for oil and gas solid waste disposal.

    Science.gov (United States)

    Lyman, Seth N; Mansfield, Marc L

    2018-04-13

    Solid or sludgy hydrocarbon waste is a by-product of oil and gas exploration and production. One commonly used method of disposing of this waste is landfarming. Landfarming involves spreading hydrocarbon waste on soils, tilling it into the soil, and allowing it to biodegrade. We used a dynamic flux chamber to measure fluxes of methane, a suite of 54 nonmethane hydrocarbons, and light alcohols from an active and a remediated landfarm in eastern Utah. Fluxes from the remediated landfarm were not different from a polytetrafluoroethylene (PTFE) sheet or from undisturbed soils in the region. Fluxes of methane, total nonmethane hydrocarbons, and alcohols from the landfarm in active use were 1.41 (0.37, 4.19) (mean and 95% confidence limits), 197.90 (114.72, 370.46), and 4.17 (0.03, 15.89) mg m -2  hr -1 , respectively. Hydrocarbon fluxes were dominated by alkanes, especially those with six or more carbons. A 2-ha landfarm with fluxes of the magnitude we observed in this study would emit 95.3 (54.3, 179.7) kg day -1 of total hydrocarbons, including 11.2 (4.3, 33.9) kg day -1 of BTEX (benzene, toluene, ethylbenzene, and xylenes). Solid and sludgy hydrocarbon waste from the oil and gas industry is often disposed of by landfarming, in which wastes are tilled into soil and allowed to decompose. We show that a land farm in Utah emitted a variety of organic compounds into the atmosphere, including hazardous air pollutants and compounds that form ozone. We calculate that a 2-ha landfarm facility would emit 95.0 ± 66.0 kg day -1 of total hydrocarbons, including 11.1 ± 1.5 kg day -1 of BTEX (benzene, toluene, ethylbenzene, and xylenes).

  1. Abnormal gas-liquid-solid phase transition behaviour of water observed with in situ environmental SEM.

    Science.gov (United States)

    Chen, Xin; Shu, Jiapei; Chen, Qing

    2017-04-24

    Gas-liquid-solid phase transition behaviour of water is studied with environmental scanning electron microscopy for the first time. Abnormal phenomena are observed. At a fixed pressure of 450 Pa, with the temperature set to -7 °C, direct desublimation happens, and ice grows continuously along the substrate surface. At 550 Pa, although ice is the stable phase according to the phase diagram, metastable liquid droplets first nucleate and grow to ~100-200 μm sizes. Ice crystals nucleate within the large sized droplets, grow up and fill up the droplets. Later, the ice crystals grow continuously through desublimation. At 600 Pa, the metastable liquid grows quickly, with some ice nuclei floating in it, and the liquid-solid coexistence state exists for a long time. By lowering the vapour pressure and/or increasing the substrate temperature, ice sublimates into vapour phase, and especially, the remaining ice forms a porous structure due to preferential sublimation in the concave regions, which can be explained with surface tension effect. Interestingly, although it should be forbidden for ice to transform into liquid phase when the temperature is well below 0 °C, liquid like droplets form during the ice sublimation process, which is attributed to the surface tension effect and the quasiliquid layers.

  2. Reversible solid oxide fuel cell for natural gas/renewable hybrid power generation systems

    Science.gov (United States)

    Luo, Yu; Shi, Yixiang; Zheng, Yi; Cai, Ningsheng

    2017-02-01

    Renewable energy (RE) is expected to be the major part of the future energy. Presently, the intermittence and fluctuation of RE lead to the limitation of its penetration. Reversible solid oxide fuel cell (RSOFC) as the energy storage device can effectively store the renewable energy and build a bidirectional connection with natural gas (NG). In this paper, the energy storage strategy was designed to improve the RE penetration and dynamic operation stability in a distributed system coupling wind generators, internal combustion engine, RSOFC and lithium-ion batteries. By compromising the relative deviation of power supply and demand, RE penetration, system efficiency and capacity requirement, the strategy that no more than 36% of the maximum wind power output is directly supplied to users and the other is stored by the combination of battery and reversible solid oxide fuel cell is optimal for the distributed system. In the case, the RE penetration reached 56.9% and the system efficiency reached 55.2%. The maximum relative deviation of power supply and demand is also lower than 4%, which is significantly superior to that in the wind curtailment case.

  3. Lattice Boltzmann simulation of the gas-solid adsorption process in reconstructed random porous media

    Science.gov (United States)

    Zhou, L.; Qu, Z. G.; Ding, T.; Miao, J. Y.

    2016-04-01

    The gas-solid adsorption process in reconstructed random porous media is numerically studied with the lattice Boltzmann (LB) method at the pore scale with consideration of interparticle, interfacial, and intraparticle mass transfer performances. Adsorbent structures are reconstructed in two dimensions by employing the quartet structure generation set approach. To implement boundary conditions accurately, all the porous interfacial nodes are recognized and classified into 14 types using a proposed universal program called the boundary recognition and classification program. The multiple-relaxation-time LB model and single-relaxation-time LB model are adopted to simulate flow and mass transport, respectively. The interparticle, interfacial, and intraparticle mass transfer capacities are evaluated with the permeability factor and interparticle transfer coefficient, Langmuir adsorption kinetics, and the solid diffusion model, respectively. Adsorption processes are performed in two groups of adsorbent media with different porosities and particle sizes. External and internal mass transfer resistances govern the adsorption system. A large porosity leads to an early time for adsorption equilibrium because of the controlling factor of external resistance. External and internal resistances are dominant at small and large particle sizes, respectively. Particle size, under which the total resistance is minimum, ranges from 3 to 7 μm with the preset parameters. Pore-scale simulation clearly explains the effect of both external and internal mass transfer resistances. The present paper provides both theoretical and practical guidance for the design and optimization of adsorption systems.

  4. Stochastic four-way coupling of gas-solid flows for Large Eddy Simulations

    Science.gov (United States)

    Curran, Thomas; Denner, Fabian; van Wachem, Berend

    2017-11-01

    The interaction of solid particles with turbulence has for long been a topic of interest for predicting the behavior of industrially relevant flows. For the turbulent fluid phase, Large Eddy Simulation (LES) methods are widely used for their low computational cost, leaving only the sub-grid scales (SGS) of turbulence to be modelled. Although LES has seen great success in predicting the behavior of turbulent single-phase flows, the development of LES for turbulent gas-solid flows is still in its infancy. This contribution aims at constructing a model to describe the four-way coupling of particles in an LES framework, by considering the role particles play in the transport of turbulent kinetic energy across the scales. Firstly, a stochastic model reconstructing the sub-grid velocities for the particle tracking is presented. Secondly, to solve particle-particle interaction, most models involve a deterministic treatment of the collisions. We finally introduce a stochastic model for estimating the collision probability. All results are validated against fully resolved DNS-DPS simulations. The final goal of this contribution is to propose a global stochastic method adapted to two-phase LES simulation where the number of particles considered can be significantly increased. Financial support from PetroBras is gratefully acknowledged.

  5. Optimisation of environmental gas cleaning routes for solid wastes cogeneration systems. Part II - Analysis of waste incineration combined gas/steam cycle

    International Nuclear Information System (INIS)

    Holanda, Marcelo R.; Perrella Balestieri, Jose A.

    2008-01-01

    In the first paper of this paper (Part I), conditions were presented for the gas cleaning technological route for environomic optimisation of a cogeneration system based in a thermal cycle with municipal solid waste incineration. In this second part, an environomic analysis is presented of a cogeneration system comprising a combined cycle composed of a gas cycle burning natural gas with a heat recovery steam generator with no supplementary burning and a steam cycle burning municipal solid wastes (MSW) to which will be added a pure back pressure steam turbine (another one) of pure condensation. This analysis aims to select, concerning some scenarios, the best atmospheric pollutant emission control routes (rc) according to the investment cost minimisation, operation and social damage criteria. In this study, a comparison is also performed with the results obtained in the Case Study presented in Part I

  6. The application of micro-column solid phase extraction techniques for the determination of rare earth elements in actinide containing matrices

    International Nuclear Information System (INIS)

    Carney, K.P.; Cummings, D.G.

    1995-01-01

    The design and characterization of an argon segmented-solid phase extraction system is described. A 200 ul volume micro-column has been constructed for the preconcentration of rare earth elements (REEs) from salt matrices containing uranium. An inductively coupled plasma atomic emission spectrometer has been utilized for simultaneous detection of Sr, Y and the REEs (namely Ce, Eu, La, Nd, Pr, Sm) at levels ranging from 5- to 2000 ppm in LiCl/KCl samples containing U. Preconcentration factors of 100 fold have been demonstrated. The precision, linear dynamic range and column performance of the system will be presented. (author). 5 refs., 5 figs., 3 tabs

  7. Development of Tandem, Double-Focusing, Electron Impact, Gas Source Mass Spectrometer for Measurement of Rare Double-Substituted Isotoplogues in Geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Young, Edward D. [University of California, Los Angeles, CA (United States)

    2015-07-30

    This project culminated in construction and delivery of the world’s first large-radius gas-source isotope ratio mass spectrometer that permits unparalleled analyses of the stable isotopic composition of methane gas. The instrument, referred to as the “Panorama” and installed at UCLA in March 2015, can now be used to determine the relative abundances of rare isotopic species of methane that serve as tracers of temperature of formation and/or subsequent processing of gas. With this technology we can begin to delineate different sources and sinks of methane isotopically in ways not possible until now.

  8. Hydrogen Production from Water by Photolysis, Sonolysis and Sonophotolysis with Solid Solutions of Rare Earth, Gallium and Indium Oxides as Heterogeneous Catalysts

    Directory of Open Access Journals (Sweden)

    Marta Penconi

    2015-07-01

    Full Text Available In this work, we present the hydrogen production by photolysis, sonolysis and sonophotolysis of water in the presence of newly synthesized solid solutions of rare earth, gallium and indium oxides playing as catalysts. From the experiments of photolysis, we found that the best photocatalyst is the solid solution Y0.8Ga0.2InO3 doped by sulphur atoms. In experiments of sonolysis, we optimized the rate of hydrogen production by changing the amount of water, adding ethanol and tuning the power of our piezoelectric transducer. Finally, we performed sonolysis and sonophotolysis experiments in the presence of S:Y0.8Ga0.2InO3 finding a promising synergistic effect of UV-visible electromagnetic waves and 38 kHz ultrasound waves in producing H2.

  9. Two-dimensional simulation of gas concentration impedance for a planar solid oxide fuel cell

    International Nuclear Information System (INIS)

    Fadaei, M.; Mohammadi, R.; Ghassemi, M.

    2014-01-01

    Highlights: • The 2D simulation shows another feature in concentration impedance. • The channel gas transport causes a capacitive behavior. • Anode polarization variation has a significant influence on velocity distribution. • The influence of 2D simulation is important for channel height bigger than 2 mm. - Abstract: This paper presents a two-dimensional model for a planar solid oxide fuel cell (SOFC) anode in order to simulate the steady-state performance characteristics as well as the electrochemical impedance spectra. The developed model couples the mass transport with the electrochemical kinetics. The transient conservation equations (momentum and species equations) are solved numerically and the linear kinetic is used for the anode electrochemistry. In order to solve the system of the nonlinear equations, an in-house code based on the finite volume method is developed and utilized. A parametric study is also carried out and the results are discussed. Results show a capacitive semicircle in the Nyquist plot which is identical to the gas concentration impedance. The simulation results are in good agreement with published data

  10. The impact of municipal solid waste management on greenhouse gas emissions in the United States.

    Science.gov (United States)

    Weitz, Keith A; Thorneloe, Susan A; Nishtala, Subba R; Yarkosky, Sherry; Zannes, Maria

    2002-09-01

    Technological advancements, environmental regulations, and emphasis on resource conservation and recovery have greatly reduced the environmental impacts of municipal solid waste (MSW) management, including emissions of greenhouse gases (GHGs). This study was conducted using a life-cycle methodology to track changes in GHG emissions during the past 25 years from the management of MSW in the United States. For the baseline year of 1974, MSW management consisted of limited recycling, combustion without energy recovery, and landfilling without gas collection or control. This was compared with data for 1980, 1990, and 1997, accounting for changes in MSW quantity, composition, management practices, and technology. Over time, the United States has moved toward increased recycling, composting, combustion (with energy recovery) and landfilling with gas recovery, control, and utilization. These changes were accounted for with historical data on MSW composition, quantities, management practices, and technological changes. Included in the analysis were the benefits of materials recycling and energy recovery to the extent that these displace virgin raw materials and fossil fuel electricity production, respectively. Carbon sinks associated with MSW management also were addressed. The results indicate that the MSW management actions taken by U.S. communities have significantly reduced potential GHG emissions despite an almost 2-fold increase in waste generation. GHG emissions from MSW management were estimated to be 36 million metric tons carbon equivalents (MMTCE) in 1974 and 8 MMTCE in 1997. If MSW were being managed today as it was in 1974, GHG emissions would be approximately 60 MMTCE.

  11. Silica, alumina and aluminosilicates as solid stationary phases in gas chromatography

    Directory of Open Access Journals (Sweden)

    S. Faramawy

    2016-09-01

    Full Text Available Silica, alumina and Aluminosilicates of different Si/Al ratios were prepared by conventional precipitation or co-precipitation methods and then subjected to thermal treatment at 800 °C. The parent and thermally treated materials were characterized by means of FTIR, SEM and thermal analysis (DTA and TGA in order to elucidate the main structural properties. Surface textural characteristics were investigated by means of nitrogen adsorption–desorption isotherms at −196 °C. Pore size distribution curves indicated the presence of mesopores (10–150 Å exhibiting maxima at 35 Å. The maxima were shifted toward higher values by increasing the alumina content. Thermodynamic parameters, ΔH, ΔG and ΔS, were determined by means of inverse gas chromatography using n-hexane as a probe. The untreated and thermally treated materials were tested as solid stationary phases in gas chromatography. The separation efficiency of various non polar and polar compounds was explained in terms of surface texture and thermodynamic parameters.

  12. Effect of cathode gas humidification on performance and durability of Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Hagen, Anke; Liu, Yi-Lin

    2010-01-01

    The effect of cathode inlet gas humidification was studied on single anode supported Solid Oxide Fuel Cells (SOFC's). The studied cells were Risø 2 G and 2.5 G. The former consists of a LSM:YSZ composite cathode, while the latter consists of a LSCF:CGO composite cathode on a CGO protection layer....... The humidification effect was found to be dependent on both the degree of humidification and the cathode polarization. No significant effect of humidification was found at OCV which rules out the possibility of a traditional poisoning effect with a blocking of active sites. Post-mortem high resolution FEG......-SEM analysis showed clear changes at and around the cathode/electrolyte contact area. In contrast to Risø 2 G cells, a very high tolerance towards humidification of cathode gas air was observed for Risø 2.5 G cells with no detectable effect of humidification even when the humidification was as high as 12.8 mol%...

  13. Well-to-Wheels Analysis of Compressed Natural Gas and Ethanol from Municipal Solid Waste

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Uisung [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Han, Jeongwoo [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division

    2016-10-01

    The amount of municipal solid waste (MSW) generated in the United States was estimated at 254 million wet tons in 2013, and around half of that generated waste was landfilled. There is a huge potential in recovering energy from that waste, since around 60% of landfilled material is biomass-derived waste that has high energy content. In addition, diverting waste for fuel production avoids huge fugitive emissions from landfills, especially uncontrolled CH4 emissions, which are the third largest anthropogenic CH4 source in the United States. Lifecycle analysis (LCA) is typically used to evaluate the environmental impact of alternative fuel production pathways. LCA of transportation fuels is called well-to-wheels (WTW) and covers all stages of the fuel production pathways, from feedstock recovery (well) to vehicle operation (wheels). In this study, the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET®) model developed by Argonne National Laboratory is used to evaluate WTW greenhouse gas (GHG) emissions and fossil fuel consumption of waste-derived fuels. Two waste-to-energy (WTE) pathways have been evaluated – one for compressed natural gas (CNG) production using food waste via anaerobic digestion, and the other for ethanol production from yard trimmings via fermentation processes. Because the fuel production pathways displace current waste management practices (i.e., landfilling waste), we use a marginal approach that considers only the differences in emissions between the counterfactual case and the alternative fuel production case.

  14. Diversity and dynamics of dominant and rare bacterial taxa in replicate sequencing batch reactors operated under different solids retention time

    KAUST Repository

    Bagchi, Samik; Garcia Tellez, Berenice; Rao, Hari Ananda; Lamendella, Regina; Saikaly, Pascal

    2014-01-01

    In this study, 16S rRNA gene pyrosequencing was applied in order to provide a better insight on the diversity and dynamics of total, dominant, and rare bacterial taxa in replicate lab-scale sequencing batch reactors (SBRs) operated at different

  15. Recovery of Rare Earth Elements from Solid Residue of El-Sela Ore, South Eastern Desert, Egypt

    International Nuclear Information System (INIS)

    Salman, A.A.; Sharaby, C.M.; Elnagar, W.A.; Khawassek, Y.M.; Abdo, Sh.M.

    2015-01-01

    The study area of Gabal El Sela at Halaib environ is located at about 20 km west of Abu Ramad City, Egypt. An uraniferous ore material associated with REE was subjected to sulphuric acid leaching for extraction of uranium mainly followed by solid liquid separation through filtration then washing. Physical upgrading was performed upon the dry residue. Chemical treatment by 50% NaOH was carried out where about 250 g residue ground at - 200 mesh were agitated at solid / liquid ratio of 1/2 for one hour. The cake was filtered then dri ed at 100 º C . T he dried cake was subject ed to dissolution by conc. HCl at 80 º C at a solid / liquid ratio 1:1 for one hour . More than 98% of REE was leached out , and then the leach liquor was subjected to selective precipitation by HF and oxalic acid then calcination of REE oxalate

  16. Tunable Rare Earth fcu-MOF Platform: Access to Adsorption Kinetics Driven Gas/Vapor Separations via Pore Size Contraction

    KAUST Repository

    Xue, Dongxu; Belmabkhout, Youssef; Shekhah, Osama; Jiang, Hao; Adil, Karim; Cairns, Amy J; Eddaoudi, Mohamed

    2015-01-01

    Reticular chemistry approach was successfully employed to deliberately construct new rare-earth (RE, i.e. Eu3+, Tb3+ and Y3+) fcu metal‒organic frameworks (MOFs) with restricted window apertures. Controlled and selective access to the resultant contracted fcu-MOF pores permits the achievement of the requisite sorbate cut-off ideal for selective adsorption kinetics separation and/or molecular sieving of gases and vapors. Predetermined reaction conditions that permitted the formation in-situ of the 12-connected RE hexanuclear molecular building block (MBB) and the establishment of the RE-fcu-MOF plat-form, especially in the presence of 2-fluorobenzoic acid (2-FBA) as a modulator and a structure directing agent, were used to synthesize isostructural RE-1,4-NDC-fcu-MOFs based on a relatively bulkier 2-connected bridging ligand, namely 1,4-naphthalenedicarboxylate (1,4-NDC). The subsequent RE-1,4-NDC-fcu-MOF structural features, contracted windows/pores and high concentration of open metal sites combined with exceptional hydrothermal and chemical stabilities, yielded nota-ble gas/solvent separation properties, driven mostly by adsorption kinetics as exemplified in this work for n-butane/methane, butanol/methanol and butanol/water pair systems.

  17. Tunable Rare Earth fcu-MOF Platform: Access to Adsorption Kinetics Driven Gas/Vapor Separations via Pore Size Contraction

    KAUST Repository

    Xue, Dongxu

    2015-03-31

    Reticular chemistry approach was successfully employed to deliberately construct new rare-earth (RE, i.e. Eu3+, Tb3+ and Y3+) fcu metal‒organic frameworks (MOFs) with restricted window apertures. Controlled and selective access to the resultant contracted fcu-MOF pores permits the achievement of the requisite sorbate cut-off ideal for selective adsorption kinetics separation and/or molecular sieving of gases and vapors. Predetermined reaction conditions that permitted the formation in-situ of the 12-connected RE hexanuclear molecular building block (MBB) and the establishment of the RE-fcu-MOF plat-form, especially in the presence of 2-fluorobenzoic acid (2-FBA) as a modulator and a structure directing agent, were used to synthesize isostructural RE-1,4-NDC-fcu-MOFs based on a relatively bulkier 2-connected bridging ligand, namely 1,4-naphthalenedicarboxylate (1,4-NDC). The subsequent RE-1,4-NDC-fcu-MOF structural features, contracted windows/pores and high concentration of open metal sites combined with exceptional hydrothermal and chemical stabilities, yielded nota-ble gas/solvent separation properties, driven mostly by adsorption kinetics as exemplified in this work for n-butane/methane, butanol/methanol and butanol/water pair systems.

  18. Tunable Rare Earth fcu-MOF Platform: Access to Adsorption Kinetics Driven Gas/Vapor Separations via Pore Size Contraction.

    Science.gov (United States)

    Xue, Dong-Xu; Belmabkhout, Youssef; Shekhah, Osama; Jiang, Hao; Adil, Karim; Cairns, Amy J; Eddaoudi, Mohamed

    2015-04-22

    Reticular chemistry approach was successfully employed to deliberately construct new rare-earth (RE, i.e., Eu(3+), Tb(3+), and Y(3+)) fcu metal-organic frameworks (MOFs) with restricted window apertures. Controlled and selective access to the resultant contracted fcu-MOF pores permits the achievement of the requisite sorbate cutoff, ideal for selective adsorption kinetics based separation and/or molecular sieving of gases and vapors. Predetermined reaction conditions that permitted the formation in situ of the 12-connected RE hexanuclear molecular building block (MBB) and the establishment of the first RE-fcu-MOF platform, especially in the presence of 2-fluorobenzoic acid (2-FBA) as a modulator and a structure directing agent, were used to synthesize isostructural RE-1,4-NDC-fcu-MOFs based on a relatively bulkier 2-connected bridging ligand, namely 1,4-naphthalenedicarboxylate (1,4-NDC). The subsequent RE-1,4-NDC-fcu-MOF structural features, contracted windows/pores and high concentration of open metal sites combined with exceptional hydrothermal and chemical stabilities, yielded notable gas/solvent separation properties, driven mostly by adsorption kinetics as exemplified in this work for n-butane/methane, butanol/methanol, and butanol/water pair systems.

  19. Coherent and non coherent atom optics experiment with an ultra-narrow beam of metastable rare gas atoms

    International Nuclear Information System (INIS)

    Grucker, J.

    2007-12-01

    In this thesis, we present a new type of atomic source: an ultra-narrow beam of metastable atoms produced by resonant metastability exchange inside a supersonic beam of rare gas atoms. We used the coherence properties of this beam to observe the diffraction of metastable helium, argon and neon atoms by a nano-transmission grating and by micro-reflection-gratings. Then, we evidenced transitions between Zeeman sublevels of neon metastable 3 P 2 state due to the quadrupolar part of Van der Waals potential. After we showed experimental proofs of the observation of this phenomenon, we calculated the transition probabilities in the Landau - Zener model. We discussed the interest of Van der Waals - Zeeman transitions for atom interferometry. Last, we described the Zeeman cooling of the supersonic metastable argon beam ( 3 P 2 ). We have succeeded in slowing down atoms to speeds below 100 m/s. We gave experimental details and showed the first time-of-flight measurements of slowed atoms

  20. Exchange energy in the local Airy gas approximation

    DEFF Research Database (Denmark)

    Vitos, Levente; Johansson, B.; Kollár, J.

    2000-01-01

    The Airy gas model of the edge electron gas is used to construct an exchange-energy functional that is an alternative to those obtained in the local-density and generalized-gradient approximations. Test calculations for rare-gas atoms, molecules, solids, and surfaces show that the Airy gas...

  1. Eulerian numerical simulation of gas-solid flows with several particles species

    International Nuclear Information System (INIS)

    Patino-Palacios, G.

    2007-11-01

    The simulation of the multiphase flows is currently an important scientific, industrial and economic challenge. The objective of this work is to improve comprehension via simulations of poly-dispersed flows and contribute the modeling and characterizing of its hydrodynamics. The study of gas-solid systems involves the models that takes account the influence of the particles and the effects of the collisions in the context of the momentum transfer. This kind of study is covered on the framework of this thesis. Simulations achieved with the Saturne-polyphasique-Tlse code, developed by Electricite de France and co-worked with the Institut de Mecanique des Fluides de Toulouse, allowed to confirm the feasibility of approach CFD for the hydrodynamic study of the injectors and dense fluidized beds. The stages of validation concern, on the one hand, the placement of the tool for simulation in its current state to make studies of validation and sensitivity of the models and to compare the numerical results with the experimental data. In addition, the development of new physical models and their establishments in the code Saturne will allow the optimization of the industrial process. To carry out this validation in a satisfactory way, a key simulation is made, in particular a monodisperse injection and the radial force of injection in the case of a poly-disperse flow, as well as the fluidization of a column made up of solid particles. In this last case, one approached three configurations of dense fluidized beds, in order to study the influence of the grid on simulations; then, one simulates the operation of a dense fluidized bed with which one characterizes the segregation between two various species of particles. The study of the injection of the poly-disperse flows presents two configurations; a flow Co-current gas-particle in gas (Case Hishida), and in addition, a poly-phase flow in a configuration of the jet type confined with zones of recirculation and stagnation (case

  2. Direct solid-phase microextraction combined with gas and liquid chromatography for the determination of lidocaine in human urine

    NARCIS (Netherlands)

    Koster, E.H M; Hofman, N.S K; de Jong, G.J.

    Solid-phase microextraction (SPME) has been combined with gas chromatography (GC) and liquid chromatography (LC) for the determination of lidocaine in human urine. A polydimethylsiloxane (PDMS) coated fibre was directly immersed into buffered urine. Extraction conditions such as time, pH, ionic

  3. Wall-to-bed heat transfer in gas-solid fluidized beds: a computational and experimental study

    NARCIS (Netherlands)

    Patil, D.J.; Smit, J.; van Sint Annaland, M.; Kuipers, J.A.M.

    2006-01-01

    The wall-to-bed heat transfer in gas-solid fluidized beds is mainly determined by phenomena prevailing in a thermal boundary layer with a thickness in the order of magnitude of the size of a single particle. In this thermal boundary layer the temperature gradients are very steep and the local

  4. Rebuttal of the existence of solid rare earth bicarbonates and the crystal structure of holmium nitrate pentahydrate

    Energy Technology Data Exchange (ETDEWEB)

    Rincke, Christine; Schmidt, Horst; Voigt, Wolfgang [Institute for Inorganic Chemistry, TU Bergakademie Freiberg (Germany)

    2017-03-16

    The synthesis routes of Gd(HCO{sub 3}){sub 3}.5H{sub 2}O and Ho(HCO{sub 3}){sub 3}.6H{sub 2}O, which are the only known bicarbonates of rare earth metals, were refuted and the published crystal structures were discussed. Because of the structural relationship of Ho(HCO{sub 3}){sub 3}.6H{sub 2}O to rare earth nitrate hexahydrates,[] the synthesis of holmium nitrate hydrate was considered and the crystal structure of Ho(NO{sub 3}){sub 3}.5H{sub 2}O was solved by single crystal X-ray diffraction measurements. Ho(NO{sub 3}){sub 3}.5H{sub 2}O was determined to crystallize in the triclinic space group P1 (no. 2) with a = 6.5680(14) Aa, b = 9.503(2) Aa, c = 10.462(2) Aa, α = 63.739(14) , β = 94.042(2) and γ = 76.000(16) . The crystal structure consists of isolated [Ho(H{sub 2}O){sub 4}(NO{sub 3}){sub 3}] polyhedra and non-coordinating water molecules. It is isotypic to other rare earth nitrate pentahydrates. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Thermodynamic and structural study of two-dimensional melting within monolayers or rare gases or methane physically adsorbed upon the surface of layer-like solids

    International Nuclear Information System (INIS)

    Tessier, Christine

    1983-01-01

    The 2D (two-dimensional) melting of monolayers of rare gases or methane physically adsorbed on the basal face of lamellar solids (graphite, boron nitride and lamellar halides) has been studied. Two different experimental measurements have been made: i) adsorption isotherms; ii) neutron diffraction spectra. The main part of this report deals with the 2D liquid-incommensurate solid transition within monolayers of rare gases or methane adsorbed on the basal face of lamellar halides. This transition is first order. It is observed only if certain conditions of dimensional incompatibility between the substrate and the absorbate are fulfilled. It is little affected by the structure of the underlying substrate. A number of thermodynamic parameters associated with it, are constants once properly scaled. These constants agree well with theoretical estimates for 6-12 Lennard Jones particles adsorbed on a smooth surface. For the monolayer of Xe adsorbed on graphite the temperature of the tricritical point above which melting becomes a continuous transition has been measured. The isotope effect associated with 2D melting has been investigated by comparing the behaviour of monolayers of CH 4 and CD 4 adsorbed on boron nitride. The vapor pressure of Xe has been determined in the temperature range 101-120 K. (author) [fr

  6. Quantifying greenhouse gas emissions from municipal solid waste dumpsites in Cameroon.

    Science.gov (United States)

    Ngwabie, N Martin; Wirlen, Yvette L; Yinda, Godwin S; VanderZaag, Andrew C

    2018-03-02

    Open dumpsites that receive municipal solid waste are potentially significant sources of greenhouse gas (GHG) emissions into the atmosphere. There is little data available on emissions from these sources, especially in the unique climate and management of central Africa. This research aimed at quantifying CH 4 , N 2 O and CO 2 emissions from two open dumpsites in Cameroon, located in Mussaka-Buea, regional headquarters of the South West Region and in Mbellewa-Bamenda, regional headquarters of the North West Region. Emissions were measured during the wet season (May 2015 and August 2016) at the Mussaka and Mbellewa dumpsites respectively. Dumpsite surfaces were partitioned into several zones for emission measurements, based on the current activity and the age of the waste. Static flux chambers were used to quantify gas emission rates thrice a day (mornings, afternoons and evenings). Average emissions were 96.80 ± 144 mg CH 4 m -2  min -1 , 0.20 ± 0.43 mg N 2 O m -2  min -1 and 224.78 ± 312 mg CO 2 m -2  min -1 in the Mussaka dumpsite, and 213.44 ± 419 mg CH 4 m -2  min -1 , 0.15 ± 0.15 mg N 2 O m -2  min -1 and 1103.82 ± 1194 mg CO 2 m -2  min -1 at the Mbellewa dumpsite. Emissions as high as 1784 mg CH 4 m -2  min -1 , 2.3 mg N 2 O m -2  min -1 and 5448 mg CO 2 m -2  min -1 were measured from both dumpsites. Huge variations observed in emissions between the different zones on the waste surface were likely a result of the heterogeneous nature of the waste, different stages in waste decomposition and different environmental conditions within the waste. Management activities that disturb waste, such as spreading and compressing potentially increase gas emissions, while covering waste with a layer of soil potentially mitigate gas emissions. Recommendations were for dumpsites to be upgraded to sanitary landfills, and biogas production from such landfills should be exploited to reduce CH 4 emissions

  7. Greenhouse gas emissions from municipal solid waste management in Vientiane, Lao PDR.

    Science.gov (United States)

    Babel, Sandhya; Vilaysouk, Xaysackda

    2016-01-01

    Municipal solid waste (MSW) is one of the major environmental problems throughout the world including in Lao PDR. In Vientiane, due to the lack of a collection service, open burning and illegal dumping are commonly practised. This study aims to estimate the greenhouse gas (GHG) emission from the current situation of MSW management (MSWM) in Vientiane and proposes an alternative solution to reduce the GHG emission and environmental impacts. The 2006 Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories (IPCC 2006 model) are used for the estimation of GHG emission from landfill and composting. For the estimation of GHG emission from open burning, the Atmospheric Brown Clouds Emission Inventory Manual (ABC EIM) is used. In Vientiane, a total of 232, 505 tonnes year(-1) of MSW was generated in 2011. Waste generation in Vientiane is 0.69 kg per capita per day, and about 31% of the total MSW generated was directly sent to landfill (71,162 tonnes year(-1)). The total potential GHG emission from the baseline scenario in 2011 was 110,182 tonnes year(-1) CO2-eq, which is 0.15 tonne year(-1) CO2-eq per capita. From the three MSWM scenarios proposed, scenario S3, which includes recycling, composting and landfilling, seems to be an effective solution for dealing with MSW in Vientiane with less air pollution, and is environmentally friendly. The total GHG emission in scenario S3 is reduced to 91,920 tonnes year(-1) CO2-eq (47% reduction), compared with the S1 scenario where all uncollected waste is diverted to landfill. © The Author(s) 2015.

  8. Impression creep properties of a semi-solid processed magnesium-aluminum alloy containing calcium and rare earth elements

    International Nuclear Information System (INIS)

    Nami, B.; Razavi, H.; Miresmaeili, S.M.; Mirdamadi, Sh.; Shabestari, S.G.

    2011-01-01

    The creep properties of a thixoformed magnesium-aluminum alloy containing calcium and rare earth elements were studied under shear modulus-normalized stresses ranging from 0.0225 to 0.035 at temperatures of 150-212 o C using the impression creep technique. Analysis of the creep mechanism based on a power-law equation indicated that pipe diffusion-controlled dislocation climb is the dominant mechanism during creep. The alloy has a better creep resistance than high-pressure die-cast magnesium-aluminum alloy.

  9. Hydrodynamic boundary conditions for one-component liquid-gas flows on non-isothermal solid substrates

    KAUST Repository

    Xu, Xinpeng

    2012-01-01

    Recently, liquid-gas flows related to droplets, bubbles, and thin films on solid surfaces with thermal and wettability gradients have attracted widespread attention because of the many physical processes involved and their promising potential applications in biology, chemistry, and industry. Various new physical effects have been discovered at fluid-solid interfaces by experiments and molecular dynamics simulations, e.g., fluid velocity slip, temperature slip (Kapitza resistance), mechanical-thermal cross coupling, etc. There have been various models and theories proposed to explain these experimental and numerical observations. However, to the best of our knowledge,a continuum hydrodynamic model capable of predicting the temperature and velocity profiles of liquid-gas flows on non-isothermal, heterogeneous solid substrates is still absent. The purpose of this work is to construct a continuum model for simulating the liquid-gas flows on solid surfaces that are flat and rigid, and may involve wettability gradients and thermal gradients. This model is able to describe fluid velocity slip, temperature slip, and mechanical-thermal coupling that may occur at fluid-solid interfaces. For this purpose, we first employ the diffuse interface modeling to formulate the hydrodynamic equations for one-component liquid-gas flows in the bulk region. This reproduces the dynamic van der Waals theory of Onuki [Phys. Rev. Lett., 94: 054501, 2005]. We then extendWaldmann\\'s method [Z. Naturforsch. A, 22: 1269-1280, 1967] to formulate the boundary conditions at the fluid-solid interface that match the hydrodynamic equations in the bulk. The effects of the solid surface curvature are also briefly discussed in the appendix. The guiding principles of our model derivation are the conservation laws and the positive definiteness of entropy production together with the Onsager reciprocal relation. The derived model is self-consistent in the sense that the boundary conditions are

  10. Study of the obtainment of Mo_2C by gas-solid reaction in a fixed and rotary bed reactor

    International Nuclear Information System (INIS)

    Araujo, C.P.B. de; Souza, C.P. de; Souto, M.V.M.; Barbosa, C.M.; Frota, A.V.V.M.

    2016-01-01

    Carbides' synthesis via gas-solid reaction overcomes many of the difficulties found in other processes, requiring lower temperatures and reaction times than traditional metallurgic routes, for example. In carbides' synthesis in fixed bed reactors (FB) the solid precursor is permeated by the reducing/carburizing gas stream forming a packed bed without mobility. The use of a rotary kiln reactor (RK) adds a mixing character to this process, changing its fluid-particle dynamics. In this work ammonium molybdate was subjected to carbo-reduction reaction (CH4 / H2) in both reactors under the same gas flow (15L / h) and temperature (660 ° C) for 180 minutes. Complete conversion was observed Mo2C (dp = 18.9nm modal particles sizes' distribution) in the fixed bed reactor. In the RK reactor this conversion was only partial (∼ 40%) and Mo2C and MoO3 (34nm dp = bimodal) could be observed on the produced XRD pattern. Partial conversion was attributed to the need to use higher solids loading in the reactor CR (50% higher) to avoid solids to centrifuge. (author)

  11. Generation of Attosecond Light Pulses from Gas and Solid State Media

    Directory of Open Access Journals (Sweden)

    Stefanos Chatziathanasiou

    2017-03-01

    Full Text Available Real-time observation of ultrafast dynamics in the microcosm is a fundamental approach for understanding the internal evolution of physical, chemical and biological systems. Tools for tracing such dynamics are flashes of light with duration comparable to or shorter than the characteristic evolution times of the system under investigation. While femtosecond (fs pulses are successfully used to investigate vibrational dynamics in molecular systems, real time observation of electron motion in all states of matter requires temporal resolution in the attosecond (1 attosecond (asec = 10−18 s time scale. During the last decades, continuous efforts in ultra-short pulse engineering led to the development of table-top sources which can produce asec pulses. These pulses have been synthesized by using broadband coherent radiation in the extreme ultraviolet (XUV spectral region generated by the interaction of matter with intense fs pulses. Here, we will review asec pulses generated by the interaction of gas phase media and solid surfaces with intense fs IR laser fields. After a brief overview of the fundamental process underlying the XUV emission form these media, we will review the current technology, specifications and the ongoing developments of such asec sources.

  12. Diffusion and Gas Conversion Analysis of Solid Oxide Fuel Cells at Loads via AC Impedance

    Directory of Open Access Journals (Sweden)

    Robert U. Payne

    2011-01-01

    Full Text Available Impedance measurements were conducted under practical load conditions in solid oxide fuel cells of differing sizes. For a 2 cm2 button cell, impedance spectra data were separately measured for the anode, cathode, and total cell. Improved equivalent circuit models are proposed and applied to simulate each of measured impedance data. Circuit elements related to the chemical and physical processes have been added to the total-cell model to account for an extra relaxation process in the spectra not measured at either electrode. The processes to which elements are attributed have been deduced by varying cell temperature, load current, and hydrogen concentration. Spectra data were also obtained for a planar stack of five 61 cm2 cells and the individual cells therein, which were fitted to a simplified equivalent circuit model of the total button cell. Similar to the button cell, the planar cells and stack exhibit a pronounced low-frequency relaxation process, which has been attributed to concentration losses, that is, the combined effects of diffusion and gas conversion. The simplified total-cell model approximates well the dynamic behavior of the SOFC cells and the whole stack.

  13. Magnetic solid phase extraction and gas chromatography-mass spectrometrical analysis of sixteen polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Cai, Ying; Yan, Zhihong; NguyenVan, Manh; Wang, Lijia; Cai, Qingyun

    2015-08-07

    Fluorenyl functionalized superparamagnetic core/shell magnetic nanoparticles (MNPs, Fe3O4@SiO2@Flu) were prepared and characterized by transmission electron microscope, X-ray diffraction and infrared spectroscopy. The MNPs having an average diameter of 200nm were then used as solid-phase extraction sorbent for the determination of 16 priority pollutants polycyclic aromatic hydrocarbons (PAHs) in water samples designated by United States Environmental Protection Agency (U.S. EPA). The main influencing parameters, including sorbent amount, desorption solvent, sample volume and extraction time were optimized. Analyses were performed on gas chromatography-mass spectrometry (GC-MS) using selected ion monitoring (SIM) mode. Method validation proved the feasibility of the developed sorbents for the quantitation of the investigated analytes at trace levels. Limit of detection ranging from 0.5 to 4.0ng/L were obtained. The repeatability was investigated by evaluating the intra- and inter-day precisions with relative standard deviations (RSDs) lower than 13.1%. Finally, the proposed method was successfully applied for the determination of PAHs in water samples with the recoveries in the range of 96.0-106.7%. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Identification and fingerprinting of biodiesel blends by solid phase extraction and gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Z. [Environment Canada, Ottawa, ON (Canada). Emergencies Science and Technology Section, Emergencies, Operational Analytical Laboratories and Research Support Division; China Univ. of Geosciences, Wuhan (China). School of Environmental Studies; Hollebone, B.; Wang, Z.; Yang, C.; Landriault, M. [Environment Canada, Ottawa, ON (Canada). Emergencies Science and Technology Section, Emergencies, Operational Analytical Laboratories and Research Support Division

    2009-07-01

    Interest in biodiesel as a replacement for petroleum diesel fuel is growing. In North America, biodiesels are produced by the methyl esterification of plant and animal triglycerides, resulting in complex mixtures composed of fatty acid methyl esters (FAMEs). It is important for both environmental forensic and remediation purposes to determine diesel and biodiesel origins, and the biodiesel content when it is blended with conventional petroleum diesel. This paper reported on a study that combined 2 methods to determine biodiesel levels in blended fuels. Micro-column fractionation of FAMEs involving solid phase extraction (SPE) was combined with gas chromatography-mass spectrometry (GC/MS) to achieve detailed chemical fingerprinting of blends, including the identification and quantification of individual aliphatic hydrocarbons, aromatic hydrocarbons, fatty acid alkyl esters, and free sterols. Fractionation of the fuel samples was optimized for separation of fatty acid esters, free sterols from petroleum hydrocarbons into 4 fractions, notably aliphatic, aromatic, fatty-acid ester and polar components. A sum of the FAME components was used to determine an unknown blend level in freshly-prepared samples. This study showed that this method has great potential for identifying biodiesel in diesel fuel blends and could form the basis of a method for biodiesel-contaminated environmental samples. 28 refs., 5 tabs., 4 figs.

  15. Identification and fingerprinting of biodiesel blends by solid phase extraction and gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    Yang, Z.; China Univ. of Geosciences, Wuhan; Hollebone, B.; Wang, Z.; Yang, C.; Landriault, M.

    2009-01-01

    Interest in biodiesel as a replacement for petroleum diesel fuel is growing. In North America, biodiesels are produced by the methyl esterification of plant and animal triglycerides, resulting in complex mixtures composed of fatty acid methyl esters (FAMEs). It is important for both environmental forensic and remediation purposes to determine diesel and biodiesel origins, and the biodiesel content when it is blended with conventional petroleum diesel. This paper reported on a study that combined 2 methods to determine biodiesel levels in blended fuels. Micro-column fractionation of FAMEs involving solid phase extraction (SPE) was combined with gas chromatography-mass spectrometry (GC/MS) to achieve detailed chemical fingerprinting of blends, including the identification and quantification of individual aliphatic hydrocarbons, aromatic hydrocarbons, fatty acid alkyl esters, and free sterols. Fractionation of the fuel samples was optimized for separation of fatty acid esters, free sterols from petroleum hydrocarbons into 4 fractions, notably aliphatic, aromatic, fatty-acid ester and polar components. A sum of the FAME components was used to determine an unknown blend level in freshly-prepared samples. This study showed that this method has great potential for identifying biodiesel in diesel fuel blends and could form the basis of a method for biodiesel-contaminated environmental samples. 28 refs., 5 tabs., 4 figs.

  16. Numerical simulation of gas-solid two-phase flow in U-beam separator

    International Nuclear Information System (INIS)

    Zhou, X Y; Chen, X P; Dou, H S; Zhang, H Z; Ruan, J M

    2015-01-01

    Numerical simulation is carried out for gas-solid two-phase flow in a U-beam separator. In this study, the U-beam is altered with the inlet fins in order to improve the performance of the separator. The inlet fin angle of the separator are 30°, 35°, 40°, 45°, 50°, 55 ° and 60°. The governing equations are the Reynolds-Averaged Navier-Stokes equation with the standard k-ε model and the discrete phase model (DPM) describing the discrete two - phase flow as well as stochastic tracking model. Results show that the pressure drop deviation with fins is within 3% from those without fins. It is found that there is a maximum separation efficiency at the fin angle of 35°. Fin induces generation of a stagnation region which could collect particles and lead to change of vortical structures. The fin induced flow also causes the turbulent intensity inside the baffle to decrease to facilitate separation

  17. Solid-phase microextraction gas chromatography-mass spectrometry determination of fragrance allergens in baby bathwater.

    Science.gov (United States)

    Lamas, J Pablo; Sanchez-Prado, Lucia; Garcia-Jares, Carmen; Llompart, Maria

    2009-07-01

    A method based on solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) has been optimized for the determination of fragrance allergens in water samples. This is the first study devoted to this family of cosmetic ingredients performed by SPME. The influence of parameters such as fibre coating, extraction and desorption temperatures, salting-out effect and sampling mode on the extraction efficiency has been studied by means of a mixed-level factorial design, which allowed the study of the main effects as well as two-factor interactions. Excluding desorption temperature, the other parameters were, in general, very important for the achievement of high response. The final procedure was based on headspace sampling at 100 degrees C, using polydimethylsiloxane/divinylbenzene fibres. The method showed good linearity and precision for all compounds, with detection limits ranging from 0.001 to 0.3 ng mL(-1). Reliability was demonstrated through the evaluation of the recoveries in different real water samples, including baby bathwater and swimming pool water. The absence of matrix effects allowed the use of external standard calibration to quantify the target compounds in the samples. The proposed procedure was applied to the determination of allergens in several real samples. All the target compounds were found in the samples, and, in some cases, at quite high concentrations. The presence and the levels of these chemicals in baby bathwater should be a matter of concern.

  18. Greenhouse gas emission mitigation relevant to changes in municipal solid waste management system.

    Science.gov (United States)

    Pikoń, Krzysztof; Gaska, Krzysztof

    2010-07-01

    Standard methods for assessing the environmental impact of waste management systems are needed to underpin the development and implementation of sustainable waste management practice. Life cycle assessment (LCA) is a tool for comprehensively ensuring such assessment and covers all impacts associated with waste management. LCA is often called "from cradle to grave" analysis. This paper integrates information on the greenhouse gas (GHG) implications of various management options for some of the most common materials in municipal solid waste (MSW). Different waste treatment options for MSW were studied in a system analysis. Different combinations of recycling (cardboard, plastics, glass, metals), biological treatment (composting), and incineration as well as land-filling were studied. The index of environmental burden in the global warming impact category was calculated. The calculations are based on LCA methodology. All emissions taking place in the whole life cycle system were taken into account. The analysis included "own emissions," or emissions from the system at all stages of the life cycle, and "linked emissions," or emissions from other sources linked with the system in an indirect way. Avoided emissions caused by recycling and energy recovery were included in the analysis. Displaced emissions of GHGs originate from the substitution of energy or materials derived from waste for alternative sources. The complex analysis of the environmental impact of municipal waste management systems before and after application of changes in MSW systems according to European Union regulations is presented in this paper. The evaluation is made for MSW systems in Poland.

  19. Development of a Reduced-Order Model for Reacting Gas-Solids Flow using Proper Orthogonal Decomposition

    Energy Technology Data Exchange (ETDEWEB)

    McDaniel, Dwayne [Florida International Univ., Miami, FL (United States); Dulikravich, George [Florida International Univ., Miami, FL (United States); Cizmas, Paul [Florida International Univ., Miami, FL (United States)

    2017-11-27

    This report summarizes the objectives, tasks and accomplishments made during the three year duration of this research project. The report presents the results obtained by applying advanced computational techniques to develop reduced-order models (ROMs) in the case of reacting multiphase flows based on high fidelity numerical simulation of gas-solids flow structures in risers and vertical columns obtained by the Multiphase Flow with Interphase eXchanges (MFIX) software. The research includes a numerical investigation of reacting and non-reacting gas-solids flow systems and computational analysis that will involve model development to accelerate the scale-up process for the design of fluidization systems by providing accurate solutions that match the full-scale models. The computational work contributes to the development of a methodology for obtaining ROMs that is applicable to the system of gas-solid flows. Finally, the validity of the developed ROMs is evaluated by comparing the results against those obtained using the MFIX code. Additionally, the robustness of existing POD-based ROMs for multiphase flows is improved by avoiding non-physical solutions of the gas void fraction and ensuring that the reduced kinetics models used for reactive flows in fluidized beds are thermodynamically consistent.

  20. An investigation of particle behavior in gas-solid horizontal pipe flow by an extended LDA technique

    Energy Technology Data Exchange (ETDEWEB)

    Yong Lu; Donald H. Glass; William J. Easson [University of Edinburgh, Edinburgh (United Kingdom). Institute for Materials and Processes

    2009-12-15

    An extended Laser Doppler Anemometry (LDA) technique has been developed to measure the distributions of particle velocities and particle number rates over a whole pipe cross-section in a dilute pneumatic conveying system. The first extension concentrates on the transform matrix for predicting the laser beams' cross point in a pipe according to the shift coordinate of the 3D computer-controlled traverse system on which the probes of the LDA system were mounted. The second focuses on the proper LDA sample rate for the measurement of gas-solid pipe flow with polydisperse particles. A suitable LDA sample rate should ensure that enough data is recorded in the measurement interval to precisely calculate the particle mean velocity or other statistical values at every sample point. The present study explores the methodology as well as the fundamentals of measurements, using a laser facility, of the cross-sectional distributions of solid phase. In the horizontal gas-solid pipe flow (glass beads less than 110 {mu}m), the experimental data show that the cross-sectional flow patterns of the solid phase can be classified by annulus-like flow describing the axial particle velocity contours and stratified flow characterising particle number rate distribution over a cross-section. Thus, the cross-sectional flow pattern of the solid phase in a horizontal pipe may be annular or stratified dependent on whether the axial particle velocity or particle number rate is the phenomenon studied. 13 refs., 16 figs., 1 tab.

  1. Theoretical treatment of the spin-orbit coupling in the rare gas oxides NeO, ArO, KrO, and XeO

    Science.gov (United States)

    Langhoff, S. R.

    1980-01-01

    Off-diagonal spin-orbit matrix elements are calculated as a function of internuclear distance for the rare gas oxides NeO, ArO, KrO, and XeO using the full microscopic spin-orbit Hamiltonian, including all one- and two-electron integrals, and POL-CI wave functions comparable to those of Dunning and Hay (1977). A good agreement was found when comparing these results in detail with the calculations of Cohen, Wadt and Hay (1979) that utilize an effective one-electron one-center spin-orbit operator. For the rare gas oxide molecules, it is suggested that the numerical results are a more sensitive test of the wave functions (particularly to the extent of charge transfer) than the exact evaluation of all terms in the full spin-orbit operator.

  2. Study of Pair and many-body interactions in rare-gas halide atom clusters using negative ion zero electron kinetic energy (ZEKE) and threshold photodetachment spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yourshaw, Ivan [Univ. of California, Berkeley, CA (United States)

    1998-07-09

    The diatomic halogen atom-rare gas diatomic complexes KrBr-, XeBr-, and KrCl- are studied in this work by zero electron kinetic energy (ZEKE) spectroscopy in order to characterize the weak intermolecular diatomic potentials of these species. Also, the ZEKE and threshold photodetachment spectra of the polyatomic clusters ArnBr- (n = 2-9) and ArnI- (n = 2-19) are studied to obtain information about the non-additive effects on the interactions among the atoms. This work is part of an ongoing effort to characterize the pair and many-body potentials of the complete series of rare gas halide clusters. In these studies we obtain information about both the anionic and neutral clusters.

  3. Uncertainty quantification tools for multiphase gas-solid flow simulations using MFIX

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Rodney O. [Iowa State Univ., Ames, IA (United States); Passalacqua, Alberto [Iowa State Univ., Ames, IA (United States)

    2016-02-01

    MFIX. The effect of uncertainty on the disperse-phase volume fraction, on the phase velocities and on the pressure drop inside the fluidized bed are examined, and the reconstructed PDFs are provided for the three quantities studied. Then the approach is applied to a bubbling fluidized bed with two uncertain parameters, particle-particle and particle-wall restitution coefficients. Contour plots of the mean and standard deviation of solid volume fraction, solid phase velocities and gas pressure are provided. The PDFs of the response are reconstructed using EQMOM with appropriate kernel density functions. The simulation results are compared to experimental data provided by the 2013 NETL small-scale challenge problem. Lastly, the proposed procedure is demonstrated by considering a riser of a circulating fluidized bed as an example application. The mean particle size is considered to be the uncertain input parameter. Contour plots of the mean and standard deviation of solid volume fraction, solid phase velocities, and granular temperature are provided. Mean values and confidence intervals of the quantities of interest are compared to the experiment results. The univariate and bivariate PDF reconstructions of the system response are performed using EQMOM and ECQMOM.

  4. Development of a high-density gas-jet target for nuclear astrophysics and reaction studies with rare isotope beams. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Uwe, Greife [Colorado School of Mines, Golden, CO (United States)

    2014-08-12

    The purpose of this project was to develop a high-density gas jet target that will enable a new program of transfer reaction studies with rare isotope beams and targets of hydrogen and helium that is not currently possible and will have an important impact on our understanding of stellar explosions and of the evolution of nuclear shell structure away from stability. This is the final closeout report for the project.

  5. Development of a high-density gas-jet target for nuclear astrophysics and reaction studies with rare isotope beams. Final Report

    International Nuclear Information System (INIS)

    Uwe, Greife

    2014-01-01

    The purpose of this project was to develop a high-density gas jet target that will enable a new program of transfer reaction studies with rare isotope beams and targets of hydrogen and helium that is not currently possible and will have an important impact on our understanding of stellar explosions and of the evolution of nuclear shell structure away from stability. This is the final closeout report for the project.

  6. Gulf of Mexico outer continental shelf daily oil and gas production rare projections from 1998 through 2002

    International Nuclear Information System (INIS)

    Melancon, J.M.; Roby, D.S.

    1998-02-01

    This paper provides daily oil and gas production rate projections for the Gulf of Mexico (GOM) Outer Continental Shelf (OCS) for the years 1998 through 2002. These projections represent daily oil and gas production estimates at calendar year end. In this report, daily oil production rates include both oil and condensate production, and daily gas production rates include both associated and nonassociated gas production. In addition to providing daily oil and gas production rate projections, the authors have included one figure and one table pertaining to leasing history and one table concerning exploration and development plan approvals

  7. Thermal properties of rare earth cobalt oxides and of La1- x Gd x CoO3 solid solutions

    Science.gov (United States)

    Orlov, Yu. S.; Dudnikov, V. A.; Gorev, M. V.; Vereshchagin, S. N.; Solov'ev, L. A.; Ovchinnikov, S. G.

    2016-05-01

    Powder X-ray diffraction data for the crystal structure, phase composition, and molar specific heat for La1‒ x Gd x CoO3 cobaltites in the temperature range of 300-1000 K have been analyzed. The behavior of the volume thermal expansion coefficient in cobaltites with isovalent doping in the temperature range of 100-1000 K is studied. It is found that the β( T) curve exhibits two peaks at some doping levels. The rate of the change in the occupation number for the high-spin state of cobalt ions is calculated for the compounds under study taking into account the spin-orbit interaction. With the Birch-Murnaghan equation of state, it is demonstrated that the low-temperature peak in the thermal expansion shifts with the growth of the pressure toward higher temperatures and at pressure P ˜ 7 GPa coincides with the second peak. The similarity in the behavior of the thermal expansion coefficient in the La1- x Gd x CoO3 compounds with the isovalent substitution and the undoped LnCoO3 compound (Ln is a lanthanide) is considered. For the whole series of rare earth cobalt oxides, the nature of two specific features in the temperature dependence of the specific heat and thermal expansion is revealed and their relation to the occupation number for the high-spin state of cobalt ions and to the insulator-metal transition is established.

  8. The importance of solid waste management and its reverse logistics in fuel gas city of Campina Grande – PB

    Directory of Open Access Journals (Sweden)

    Joselia Fernandes Nascimento

    2016-04-01

    Full Text Available This research aimed to identify the importance of controlling the solid waste management process generated in the posts of Campina Grande-PB fuels, still checking the current level of adequacy of the same with respect to Reverse Logistics for the proper disposal of lubricating oils used and / or contaminated, their waste and packaging. The population consisted of 56 gas stations, authorized by the National Agency of Petroleum, Natural Gas and Biofuels (ANP, and resulted in a sample, for this study, 35 stations, representing 62.50% of the universe. Data collection was carried out with the use of questionnaires and research is characterized exploratory and descriptive. The results show that 51.43% of respondents know the important role of controlling, but most do not have enough knowledge regarding PNRS, LR and management of solid waste, however, has actions that are appropriate for the proper disposal waste.

  9. Modelling the influence of the gas to melt ratio on the fraction solid of the surface in spray formed billets

    DEFF Research Database (Denmark)

    Hattel, Jesper Henri; Pryds, Nini

    2006-01-01

    the atomisation stage taking thermal coupling into consideration and the deposition of the droplets at the surface of the billet taking geometrical aspects such as shading into account. The coupling between these two models is accomplished by ensuring that the total droplet size distribution of the spray......In this paper, the relationship between the Gas to Melt Ratio (GMR) and the solid fraction of an evolving billet surface is investigated numerically. The basis for the analysis is a recently developed integrated procedure for modelling the entire spray forming process. This model includes...... is the summation of “local” droplet size distributions along the r-axis of the spray cone. The criterion for a successful process has been a predefined process window characterised by a desired solid fraction range at a certain distance from the atomizer. Inside this process window, the gas and melt flows have...

  10. Rare earth germanates

    International Nuclear Information System (INIS)

    Bondar', I.A.; Vinogradova, N.V.; Dem'yanets, L.N.

    1983-01-01

    Rare earth germanates attract close attention both as an independent class of compounds and analogues of a widely spread class of natural and synthetic minerals. The methods of rare earth germanate synthesis (solid-phase, hydrothermal) are considered. Systems on the basis of germanium and rare earth oxides, phase diagrams, phase transformations are studied. Using different chemical analysese the processes of rare earth germanate formation are investigated. IR spectra of alkali and rare earth metal germanates are presented, their comparative analysis being carried out. Crystal structures of the compounds, lattice parameters are studied. Fields of possible application of rare earth germanates are shown

  11. Method for the combustion of a gas, in fixed bed, with an oxidized solid and associated installation

    OpenAIRE

    Abanades García, Juan Carlos; Fernández García, José Ramón

    2014-01-01

    [EN] The present invention pertains to the field of the generation of energy from combustible gases, incorporating the capture of carbon dioxide for use or permanent storage and, specifically relates to cyclical methods of gas combustion with oxidized solids (chemical looping processes), in fixed bed, for solving the problem of controlling temperature in the combustion of gaseous fuels in fixed beds of metal oxides operating at high pressures, and also the associated installation.

  12. Solid-Core, Gas-Cooled Reactor for Space and Surface Power

    International Nuclear Information System (INIS)

    King, Jeffrey C.; El-Genk, Mohamed S.

    2006-01-01

    The solid-core, gas-cooled, Submersion-Subcritical Safe Space (S and 4) reactor is developed for future space power applications and avoidance of single point failures. The Mo-14%Re reactor core is loaded with uranium nitride fuel in enclosed cavities, cooled by He-30%Xe, and sized to provide 550 kWth for seven years of equivalent full power operation. The beryllium oxide reflector disassembles upon impact on water or soil. In addition to decreasing the reactor and shadow shield mass, Spectral Shift Absorber (SSA) materials added to the reactor core ensure that it remains subcritical in the worst-case submersion accident. With a 0.1 mm thick boron carbide coating on the outside surface of the core block and 0.25 mm thick iridium sleeves around the fuel stacks, the reflector outer diameter is 43.5 cm and the combined reactor and shadow shield mass is 935.1 kg. With 12.5 atom% gadolinium-155 added to the fuel, 2.0 mm diameter gadolinium-155 sesquioxide intersititial pins, and a 0.1 mm thick gadolinium-155 sesquioxide coating, the S and 4 reactor has a slightly smaller reflector outer diameter of 43.0 cm, and a total reactor and shield mass of 901.7 kg. With 8.0 atom% europium-151 added to the fuel, 2.0 mm diameter europium-151 sesquioxide interstitial pins, and a 0.1 mm thick europium-151 sesquioxide coating, the reflector's outer diameter and the total reactor and shield mass are further reduced to 41.5 cm and 869.2 kg, respectively

  13. Gas-Solid Reaction Route toward the Production of Intermetallics from Their Corresponding Oxide Mixtures

    Directory of Open Access Journals (Sweden)

    Hesham Ahmed

    2016-08-01

    Full Text Available Near-net shape forming of metallic components from metallic powders produced in situ from reduction of corresponding pure metal oxides has not been explored to a large extent. Such a process can be probably termed in short as the “Reduction-Sintering” process. This methodology can be especially effective in producing components containing refractory metals. Additionally, in situ production of metallic powder from complex oxides containing more than one metallic element may result in in situ alloying during reduction, possibly at lower temperatures. With this motivation, in situ reduction of complex oxides mixtures containing more than one metallic element has been investigated intensively over a period of years in the department of materials science, KTH, Sweden. This review highlights the most important features of that investigation. The investigation includes not only synthesis of intermetallics and refractory metals using the gas solid reaction route but also study the reaction kinetics and mechanism. Environmentally friendly gases like H2, CH4 and N2 were used for simultaneous reduction, carburization and nitridation, respectively. Different techniques have been utilized. A thermogravimetric analyzer was used to accurately control the process conditions and obtain reaction kinetics. The fluidized bed technique has been utilized to study the possibility of bulk production of intermetallics compared to milligrams in TGA. Carburization and nitridation of nascent formed intermetallics were successfully carried out. A novel method based on material thermal property was explored to track the reaction progress and estimate the reaction kinetics. This method implies the dynamic measure of thermal diffusivity using laser flash method. These efforts end up with a successful preparation of nanograined intermetallics like Fe-Mo and Ni-W. In addition, it ends up with simultaneous reduction and synthesis of Ni-WN and Ni-WC from their oxide mixtures

  14. Using of acoustic technologies for detection of explosives in gas, liquid and solid medium

    International Nuclear Information System (INIS)

    Valyaev, A. N.; Yanushkevich, V.A.

    2004-01-01

    contained acoustic radiator and detector, with probe selection of diagnostic material. That is why at first the acoustic passports will be obtained for all types of explosives and their data bank will be formed. This bank will included C (ω,T), α (ω,T) and ρ (ω,T) dependences, which will identify a presence and a specific type of explosive. We propose the universal system, that may be quickly adapted for search and diagnostics of different types of matter, including a qualitative and quantitative analysis of their few main components. This system may be realized in the development of devices, that used the acoustic techniques. The principles of system function is discussed. The practical realization of this method on example of image of alcohol beverage type. The presented 2a and 3D diagrams for system of ethyl alcohol-sugar-water solutions proved the possibilities of our technique for the operative and reliable diagnostic. The similar technique we successfully used in the development and the application of new devices for monitoring and measurements of alcohol and sugar concentrations in industrial flood plains of vodka, brandies, liqueurs, wines and champagnes at Russian plants. The principle advantages and disadvantages of the proposed technique, including the special engineering and design elements of the devices for diagnostic of explosives are under consideration. It is noticed, that this technique may be used for detection of solid and liquid explosives in grounds and in another solid materials, in water and gas mediums and we recommend to use it as the special monitoring method for very important large objects, such as dams of uranium tailing storages in Tyan-Shan Mountains

  15. Solid-state harmonics beyond the atomic limit.

    Science.gov (United States)

    Ndabashimiye, Georges; Ghimire, Shambhu; Wu, Mengxi; Browne, Dana A; Schafer, Kenneth J; Gaarde, Mette B; Reis, David A

    2016-06-23

    Strong-field laser excitation of solids can produce extremely nonlinear electronic and optical behaviour. As recently demonstrated, this includes the generation of high harmonics extending into the vacuum-ultraviolet and extreme-ultraviolet regions of the electromagnetic spectrum. High harmonic generation is shown to occur fundamentally differently in solids and in dilute atomic gases. How the microscopic mechanisms in the solid and the gas differ remains a topic of intense debate. Here we report a direct comparison of high harmonic generation in the solid and gas phases of argon and krypton. Owing to the weak van der Waals interaction, rare (noble)-gas solids are a near-ideal medium in which to study the role of high density and periodicity in the generation process. We find that the high harmonic generation spectra from the rare-gas solids exhibit multiple plateaus extending well beyond the atomic limit of the corresponding gas-phase harmonics measured under similar conditions. The appearance of multiple plateaus indicates strong interband couplings involving multiple single-particle bands. We also compare the dependence of the solid and gas harmonic yield on laser ellipticity and find that they are similar, suggesting the importance of electron-hole recollision in these solids. This implies that gas-phase methods such as polarization gating for attosecond pulse generation and orbital tomography could be realized in solids.

  16. The complete information for phenomenal distributed parameter control of multicomponent chemical processes in gas, fluid and solid phase

    International Nuclear Information System (INIS)

    Niemiec, W.

    1985-01-01

    A constitutive mathematical model of distributed parameters of multicomponent chemical processes in gas, fluid and solid phase is utilized to the realization of phenomenal distributed parameter control of these processes. Original systems of partial differential constitutive state equations, in the following derivative forms /I/, /II/ and /III/ are solved in this paper from the point of view of information for phenomenal distributed parameter control of considered processes. Obtained in this way for multicomponent chemical processes in gas, fluid and solid phase: -dynamical working space-time characteristics/analytical solutions in working space-time of chemical reactors/, -dynamical phenomenal Green functions as working space-time transfer functions, -statical working space characteristics /analytical solutions in working space of chemical reactors/, -statical phenomenal Green functions as working space transfer functions, are applied, as information for realization of constitutive distributed parameter control of mass, energy and momentum aspects of above processes. Two cases are considered by existence of: A/sup o/ - initial conditions, B/sup o/ - initial and boundary conditions, for multicomponent chemical processes in gas, fluid and solid phase

  17. Laser-induced carbon plasma emission spectroscopic measurements on solid targets and in gas-phase optical breakdown

    International Nuclear Information System (INIS)

    Nemes, Laszlo; Keszler, Anna M.; Hornkohl, James O.; Parigger, Christian

    2005-01-01

    We report measurements of time- and spatially averaged spontaneous-emission spectra following laser-induced breakdown on a solid graphite/ambient gas interface and on solid graphite in vacuum, and also emission spectra from gas-phase optical breakdown in allene C3H4 and helium, and in CO2 and helium mixtures. These emission spectra were dominated by CII (singly ionized carbon), CIII (doubly ionized carbon), hydrogen Balmer beta (H b eta), and Swan C2 band features. Using the local thermodynamic equilibrium and thin plasma assumptions, we derived electron number density and electron temperature estimates. The former was in the 1016 cm -3 range, while the latter was found to be near 20000 K. In addition, the vibration-rotation temperature of the Swan bands of the C2 radical was determined to be between 4500 and 7000 K, using an exact theoretical model for simulating diatomic emission spectra. This temperature range is probably caused by the spatial inhomogeneity of the laser-induced plasma plume. Differences are pointed out in the role of ambient CO2 in a solid graphite target and in gas-phase breakdown plasma

  18. Solid phase extraction for analysis of biogenic carbonates by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS): an investigation of rare earth element signatures in otolith microchemistry

    International Nuclear Information System (INIS)

    Arslan, Zikri; Paulson, Anthony J.

    2003-01-01

    Uptake of trace elements into fish otoliths is governed by several factors such as life histories and environment in addition to stock and species differences. In an attempt to elucidate the elemental signatures of rare earth elements (REEs) in otoliths, a solid phase extraction (SPE) protocol was used in combination with electrothermal vaporization (ETV) as a sample introduction procedure for the determinations by inductively coupled plasma quadrupole mass spectrometry (ICP-MS). Effects of various parameters, such as carrier gas flow rate, atomization temperature and chemical modification, were examined for optimization of the conditions by ETV-ICP-MS. Atomization was achieved at 2800 deg. C. Lower temperatures (i.e. 2600 deg. C) resulted in severe memory problems due to incomplete atomization. Palladium was used as a chemical modifier. It was found that an increase in Pd concentration up to 0.5 μg in the injection volume (70 μl) led up to four-fold enhancement in the integrated signals. This phenomenon is attributed to the carrier effect of Pd rather than the stabilization since no significant losses were observed for high temperature drying around 700 deg. C even in the absence of Pd. Preconcentration was performed on-line at pH 5 by using a mini-column of Toyopearl AF-Chelate 650M chelating resin, which also eliminated the calcium matrix of otolith solutions. After preconcentration of 6.4 ml of solution, the concentrate was collected in 0.65 ml of 0.5% (v/v) HNO 3 in autosampler cups, and then analyzed by ETV-ICP-MS. The method was validated with the analysis of a fish otolith certified reference material (CRM) of emperor snapper, and then applied to samples. Results obtained from otoliths of fish captured in the same habitat indicated that otolith rare earth element concentrations are more dependent on environmental conditions of the habitat than on species differences

  19. Physical adsorption: rare-gas atoms on solid surfaces. Final report, June 1, 1980-September 30, 1982

    International Nuclear Information System (INIS)

    Cole, M.W.

    1982-09-01

    The areas of major progress are a quantitative understanding of band structure effects for He on graphite, the substrate modification of the He-He interaction on graphite, the nature of a universal physisorption potential, and the asymptotic coefficient C 3 of the van der Waals interaction between an atom and a surface. These calculations have been largely confirmed by very precise experiments, indicating the growing sophistication of this field. Their conclusions can be generalized and extended to a variety of other systems and problems

  20. Boundaries matter: Greenhouse gas emission reductions from alternative waste treatment strategies for California’s municipal solid waste

    DEFF Research Database (Denmark)

    Vergara, Sintana E.; Damgaard, Anders; Horvathc, Arpad

    2011-01-01

    How waste is managed – whether as a nuisance to be disposed of, or as a resource to be reused – directly affects local and global environmental quality. This analysis explores the GHG benefits of five treatment options for residual municipal solid waste (MSW) in California: Business As Usual...... landfills. Using two different waste LCA models, EASEWASTE (a Danish model) and WARM (a U.S. model), we find that improved biogenic waste management through anaerobic digestion and waste reduction can lead to life-cycle GHG savings when compared to Business As Usual. The magnitude of the benefits depends...... strongly on a number of model assumptions: the type of electricity displaced by waste-derived energy, how biogenic carbon is counted as a contributor to atmospheric carbon stocks, and the landfill gas collection rate. Assuming that natural gas is displaced by waste-derived energy, that 64% of landfill gas...

  1. MAKE SUPER-EARTHS, NOT JUPITERS: ACCRETING NEBULAR GAS ONTO SOLID CORES AT 0.1 AU AND BEYOND

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eve J.; Chiang, Eugene; Ormel, Chris W., E-mail: evelee@berkeley.edu, E-mail: echiang@astro.berkeley.edu, E-mail: ormel@berkeley.edu [Department of Astronomy, University of California Berkeley, Berkeley, CA 94720-3411 (United States)

    2014-12-20

    Close-in super-Earths having radii 1-4 R {sub ⊕} may possess hydrogen atmospheres comprising a few percent by mass of their rocky cores. We determine the conditions under which such atmospheres can be accreted by cores from their parent circumstellar disks. Accretion from the nebula is problematic because it is too efficient: we find that 10 M {sub ⊕} cores embedded in solar metallicity disks tend to undergo runaway gas accretion and explode into Jupiters, irrespective of orbital location. The threat of runaway is especially dire at ∼0.1 AU, where solids may coagulate on timescales orders of magnitude shorter than gas clearing times; thus nascent atmospheres on close-in orbits are unlikely to be supported against collapse by planetesimal accretion. The time to runaway accretion is well approximated by the cooling time of the atmosphere's innermost convective zone, whose extent is controlled by where H{sub 2} dissociates. Insofar as the temperatures characterizing H{sub 2} dissociation are universal, timescales for core instability tend not to vary with orbital distance—and to be alarmingly short for 10 M {sub ⊕} cores. Nevertheless, in the thicket of parameter space, we identify two scenarios, not mutually exclusive, that can reproduce the preponderance of percent-by-mass atmospheres for super-Earths at ∼0.1 AU, while still ensuring the formation of Jupiters at ≳ 1 AU. Scenario (a): planets form in disks with dust-to-gas ratios that range from ∼20× solar at 0.1 AU to ∼2× solar at 5 AU. Scenario (b): the final assembly of super-Earth cores from mergers of proto-cores—a process that completes quickly at ∼0.1 AU once begun—is delayed by gas dynamical friction until just before disk gas dissipates completely. Both scenarios predict that the occurrence rate for super-Earths versus orbital distance, and the corresponding rate for Jupiters, should trend in opposite directions, as the former population is transformed into the latter: as

  2. Production of "Green Natural Gas" Using Solid Oxide Electrolysis Cells (SOEC): Status of Technology and Costs

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Jensen, Søren Højgaard; Ebbesen, Sune Dalgaard

    2012-01-01

    energy sources only. Also dimethyl ether (DME = (CH3)2O), which might be called Liquefied Green Gas, LGG, in analogy to Liquefied Petroleum Gas, LPG, because DME has properties similar to LPG. It further gives a short review of the state of the art of electrolysis in general and SOEC in particular......This paper gives arguments in favour of using green natural gas (GNG) as storage media for the intermittent renewable energy sources. GNG is here defined as being CH4, i.e. methane, often called synthetic natural gas or substitute natural gas (SNG), produced using renewable or at least CO2 neutral....... Production of synthesis gas (H2 + CO) from CO2 and H2O using SOEC technology is evaluated. GNG and LGG can be produced from synthesis gas (or short: syngas) by means of well established commercially available catalysis technology. Finally, estimations of costs and efficiencies are presented and the relative...

  3. Coefficient of solid-gas heat transfer in particle fixed bed; Coeficiente de transferencia de calor gas-solido em leito fixo de particulas

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes Filho, Francisco

    1991-03-01

    The work presents a study on heat transfer between gas and solid phases for fixed beds in the absence of mass transfer and chemical reactions. Mathematical models presented in the literature were analyzed concerning to the assumptions made on axial dispersion in the fluid phase and interparticle thermal conductivity. Heat transfer coefficients and their dependency on flow conditions, particles and packed bed characteristics were experimentally determined through the solution of the previous mathematical models. Pressure drop behaviour for the packed beds used for the heat transfer study was also included. (author) 32 refs., 12 figs.

  4. The design of stationary and mobile solid oxide fuel cell-gas turbine systems

    Science.gov (United States)

    Winkler, Wolfgang; Lorenz, Hagen

    A general thermodynamic model has shown that combined fuel cell cycles may reach an electric-efficiency of more than 80%. This value is one of the targets of the Department of Energy (DOE) solid oxide fuel cell-gas turbine (SOFC-GT) program. The combination of a SOFC and GT connects the air flow of the heat engine and the cell cooling. The principle strategy in order to reach high electrical-efficiencies is to avoid a high excess air for the cell cooling and heat losses. Simple combined SOFC-GT cycles show an efficiency between 60 and 72%. The combination of the SOFC and the GT can be done by using an external cooling or by dividing the stack into multiple sub-stacks with a GT behind each sub-stack as the necessary heat sink. The heat exchangers (HEXs) of a system with an external cooling have the benefit of a pressurization on both sides and therefore, have a high heat exchange coefficient. The pressurization on both sides delivers a low stress to the HEX material. The combination of both principles leads to a reheat (RH)-SOFC-GT cycle that can be improved by a steam turbine (ST) cycle. The first results of a study of such a RH-SOFC-GT-ST cycle indicate that a cycle design with an efficiency of more than 80% is possible and confirm the predictions by the theoretical thermodynamic model mentioned above. The extremely short heat-up time of a thin tubular SOFC and the market entrance of the micro-turbines give the option of using these SOFC-GT designs for mobile applications. The possible use of hydrocarbons such as diesel oil is an important benefit of the SOFC. The micro-turbine and the SOFC stack will be matched depending on the start-up requirements of the mobile system. The minimization of the volume needed is a key issue. The efficiency of small GTs is lower than the efficiency of large GTs due to the influence of the leakage within the stages of GTs increasing with a decreasing size of the GT. Thus, the SOFC module pressure must be lower than in larger

  5. Performance analysis of hybrid solid oxide fuel cell and gas turbine cycle: Application of alternative fuels

    International Nuclear Information System (INIS)

    Zabihian, Farshid; Fung, Alan S.

    2013-01-01

    Highlights: • Variation of the stream properties in the syngas-fueled hybrid SOFC–GT cycle. • Detailed analysis of the operation of the methane-fueled SOFC–GT cycle. • Investigate effects of inlet fuel type and composition on performance of cycle. • Comparison of system operation when operated with and without anode recirculation. - Abstract: In this paper, the hybrid solid oxide fuel cell (SOFC) and gas turbine (GT) model was applied to investigate the effects of the inlet fuel type and composition on the performance of the cycle. This type of analysis is vital for the real world utilization of manufactured fuels in the hybrid SOFC–GT system due to the fact that these fuel compositions depends on the type of material that is processed, the fuel production process, and process control parameters. In the first part of this paper, it is shown that the results of a limited number of studies on the utilization of non-conventional fuels have been published in the open literature. However, further studies are required in this area to investigate all aspects of the issue for different configurations and assumptions. Then, the results of the simulation of the syngas-fueled hybrid SOFC–GT cycle are employed to explain the variation of the stream properties throughout the cycle. This analysis can be very helpful in understanding cycle internal working and can provide some interesting insights to the system operation. Then, the detailed information of the operation of the methane-fueled SOFC–GT cycle is presented. For both syngas- and methane-fueled cycles, the operating conditions of the equipment are presented and compared. Moreover, the comparison of the characteristics of the system when it is operated with two different schemes to provide the required steam for the cycle, with anode recirculation and with an external source of water, provides some interesting insights to the system operation. For instance, it was shown that although the physical

  6. Controlling thermal properties of dense gas fluidized beds for concentrated solar power by internal and external solids circulation

    Science.gov (United States)

    Ammendola, Paola; Bareschino, Piero; Chirone, Riccardo; Salatino, Piero; Solimene, Roberto

    2017-06-01

    Fluidization technology displays a long record of success stories, mostly related to applications to thermal and thermochemical processes, which are fostering extension to novel and relatively unexplored fields. Application of fluidized beds to collection and thermal storage of solar radiation in Concentrated Solar Power (CSP) is one of the most promising, a field which poses challenging issues and great opportunities to fluidization scientists and technologists. The potential of this growing field calls for reconsideration of some of the typical design and operation guidelines and criteria, with the goal of exploiting the inherently good thermal performances of gas-fluidized beds at their best. "Creative" and non-conventional design and operation of fluidized beds, like those based on internal and external solids circulation, may be beneficial to the enhancement of thermal diffusivity and surface-to-bed heat transfer, improving the potential for application in the very demanding context of CSP with thermal energy storage. This paper investigated: i) a fluidized bed configuration with an uneven distribution of the fluidizing gas to promote vortices in the scale of bed height (internal solids circulation); ii) a dual fluidized bed configuration characterized by an external solids circulation achieved by the operation of a riser and a bubbling fluidized bed. CFD simulations showed the hydrodynamics conditions under which the internal solids circulation was established. The hydrodynamic characterization of the external solids circulation was achieved by an experimental study carried out with different cold models. The dual fluidized bed system was optimized in terms of operating conditions and geometrical features of the connections between two fluidized beds.

  7. Power generation potential using landfill gas from Ontario municipal solid waste landfills. Appendix B2

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Twenty-six landfill sites have been identified in Ontario with potential gas production rates suitable for recovery and use in power plant applications. If 70% of the gas naturally generated from these sites was collected and utilized, ca 88 MW could be produced in 1991 (declining to 74 MW by 2001) from the gas generated. Assuming the current average generation rate of one tonne per capita, an estimated nine million tonnes of municipal refuse is produced annually in Ontario, and landfilling is expected to continue to play a major role. It is suggested that the level of gas generation identified for the year 1991 will be sustainable given that as old landfills are spent, new ones are built. The accuracy of the prediction depends largely on future government policies regarding incineration, the effects of present waste reduction programs, and approval of new landfill sites. Due to the combined costs of the gas collection system, auxiliary equipment, and gas processing system, installed cost of a landfill-gas fired power plant is high relative to that of conventional natural gas-fired plants. For landfills presently without a gas collection system, the high initial capital investment for gas field test programs and for the installation of a collection system is a barrier that deters municipalities from tapping this energy potential. 2 figs., 3 tabs

  8. The effects of rare earths on activity and surface properties of Ru/γ-Al2O3 catalyst for water gas shift reaction

    Directory of Open Access Journals (Sweden)

    Laitao Luo

    2007-04-01

    Full Text Available A series of Ru-RE/γ- Al2O3 (RE = Ce, Pr, La, Sm, Tb or Gd and Ru/γ- Al2O3 catalysts were prepared by impregnation method. The influence of rare earths on the catalytic performance of Ru/γ- Al2O3 catalyst for the water gas shift reaction was studied. The catalysts were characterized by X-ray diffraction (XRD, temperature programmed reduction (TPR, temperature programmed desorption (TPD, and CO chemisorption. The results show that the addition of rare earths increases the catalytic activity of Ru based catalyst. Among these cerium is the most remarkably. The addition of cerium increases the active surface area, improves the dispersion of ruthenium, and weakens the interaction between ruthenium and the support. Cerium also affects the adsorption and reduction properties of Ru/γ-Al2O3 catalyst.

  9. Application of the carbon dioxide-barium hydroxide hydrate gas-solid reaction for the treatment of dilute carbon dioxide-bearing gas streams

    International Nuclear Information System (INIS)

    Haag, G.L.

    1983-09-01

    The removal of trace components from gas streams via irreversible gas-solid reactions in an area of interest to the chemical engineering profession. This research effort addresses the use of fixed beds of Ba(OH) 2 hydrate flakes for the removal of an acid gas, CO 2 , from air that contains approx. 330 ppM/sub v/ CO 2 . Areas of investigation encompassed: (1) an extensive literature review of Ba(OH) 2 hydrate chemistry, (2) microscale studies on 0.150-g samples to develop a better understanding of the reaction, (3) process studies at the macroscale level with 10.2-cm-ID fixed-bed reactors, and (4) the development of a model for predicting fixed-bed performance. Experimental studies indicated fixed beds of commercial Ba(OH) 2 .8H 2 O flakes at ambient temperatures to be capable of high CO 2 -removal efficiencies (effluent concentrations 99%), and an acceptable pressure drop (1.8 kPa/m at a superficial gas velocity of 13 cm/s). Ba(OH) 2 .8H 2 O was determined to be more reactive toward CO 2 than either Ba(OH) 2 .3H 2 O or Ba(OH) 2 .1H 2 O. A key variable in the development of this fixed-bed process was relative humidity. Operation at conditions with effluent relative humidities >60% resulted in significant recrystallization and restructuring of the flake and subsequent pressure-drop problems

  10. Identification of defluidization region in a gas-solid fluidized bed using a method based on pressure fluctuation measurements

    Directory of Open Access Journals (Sweden)

    M. R. Parise

    2009-09-01

    Full Text Available Industrial applications that involve fluidized bed operations must prevent the undesirable phenomenon of partial or complete bed defluidization. Defluidization can be avoided by increasing the gas velocity and/or, in some cases, changing the solid feed conditions in the system, provided that the changes in the hydrodynamics of the flow are detected early enough. The use of a technique that can perform an early detection of the defluidization condition in industrial applications is important, in order to avoid the loss of efficiency or even an undesirable shutting down of the process. The objective of this work is to show the application of a method for early detection of the condition where the bed is tending to the defluidization, in a gas-solid fluidized bed flow. The method is based on pressure fluctuation measurements. Experimental tests are carried out using two solid particles: microcrystalline cellulose and sand. Results show that the proposed method is efficient in detecting the fluidization condition in a conventional bubbling bed regime. The potential of application of the technique is also shown for the control of the defluidization phenomenon in industry.

  11. Thermodynamic analysis of a combined gas turbine power plant with a solid oxide fuel cell for marine applications

    Directory of Open Access Journals (Sweden)

    Yousri M.A. Welaya

    2013-12-01

    Full Text Available Strong restrictions on emissions from marine power plants (particularly SOx, NOx will probably be adopted in the near future. In this paper, a combined solid oxide fuel cell (SOFC and gas turbine fuelled by natural gas is proposed as an attractive option to limit the environmental impact of the marine sector. It includes a study of a heat-recovery system for 18 MW SOFC fuelled by natural gas, to provide the electric power demand onboard commercial vessels. Feasible heat-recovery systems are investigated, taking into account different operating conditions of the combined system. Two types of SOFC are considered, tubular and planar SOFCs, operated with either natural gas or hydrogen fuels. This paper includes a detailed thermodynamic analysis for the combined system. Mass and energy balances are performed, not only for the whole plant but also for each individual component, in order to evaluate the thermal efficiency of the combined cycle. In addition, the effect of using natural gas as a fuel on the fuel cell voltage and performance is investigated. It is found that a high overall efficiency approaching 70% may be achieved with an optimum configuration using SOFC system under pressure. The hybrid system would also reduce emissions, fuel consumption, and improve the total system efficiency.

  12. Thermodynamic analysis of a combined gas turbine power plant with a solid oxide fuel cell for marine applications

    Science.gov (United States)

    Welaya, Yousri M. A.; Mosleh, M.; Ammar, Nader R.

    2013-12-01

    Strong restrictions on emissions from marine power plants (particularly SOx, NOx) will probably be adopted in the near future. In this paper, a combined solid oxide fuel cell (SOFC) and gas turbine fuelled by natural gas is proposed as an attractive option to limit the environmental impact of the marine sector. It includes a study of a heatrecovery system for 18 MW SOFC fuelled by natural gas, to provide the electric power demand onboard commercial vessels. Feasible heat-recovery systems are investigated, taking into account different operating conditions of the combined system. Two types of SOFC are considered, tubular and planar SOFCs, operated with either natural gas or hydrogen fuels. This paper includes a detailed thermodynamic analysis for the combined system. Mass and energy balances are performed, not only for the whole plant but also for each individual component, in order to evaluate the thermal efficiency of the combined cycle. In addition, the effect of using natural gas as a fuel on the fuel cell voltage and performance is investigated. It is found that a high overall efficiency approaching 70% may be achieved with an optimum configuration using SOFC system under pressure. The hybrid system would also reduce emissions, fuel consumption, and improve the total system efficiency.

  13. Characterization of three agave species by gas chromatography and solid-phase microextraction-gas chromatography-mass spectrometry.

    Science.gov (United States)

    Peña-Alvarez, Araceli; Díaz, Laura; Medina, Alejandra; Labastida, Carmen; Capella, Santiago; Vera, Luz Elena

    2004-02-20

    Steam distillation (SD) extraction-solid-phase microextraction coupled to GC-MS was developed for the determination of terpenes and Bligh-Dyer extraction-derivatization coupled with GC for the determination of fatty acids such as ethyl esters were used. It was found that the three different Agave species have the same profile of fatty acids; the quantity of these compounds is different in each Agave variety. On the other hand, different terpenes were identified in the three Agave plants studied: nine in A. salmiana, eight in A. angustifolia and 32 in A. tequilana Weber var. azul.

  14. Analytical solutions for non-linear conversion of a porous solid particle in a gas : II. non-isothermal conversion and numerical verification

    NARCIS (Netherlands)

    Brem, G.; Brouwers, J.J.H.

    1990-01-01

    In Part I, analytical solutions were given for the non-linear isothermal heterogeneous conversion of a porous solid particle. Account was taken of a reaction rate of general order with respect to the gas reactant, intrinsic reaction surface area and effective pore diffusion, which change with solid

  15. Innovative in-line separators: removal of water or sand in oil/water and gas/liquid/solid pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Jepson, Paul; Cheolho Kang; Gopal, Madan [CC Technologies, Dublin, OH (United States)

    2003-07-01

    In oil and gas production, multiphase mixtures are often separated before downstream processing. The separators are large, often 20 - 40 feet long and large diameter and use sophisticated internals. The costs are in the millions of dollars. Further, the sand and water in the flow can cause severe internal erosion and corrosion respectively before the flow reaches the separators. The CC Technologies/MIST In line Separation System is a cost-effective, efficient device for use in multiphase environments. The device is applicable for gas/solid, gas/liquid/solid and oil/water systems and offers exceptional separation between phases for a fraction of the cost of expensive gravity separators and hydro cyclones. The System contains no moving parts and is designed to be of the same diameter as the pipe, and experiences low shear forces. It can be fabricated with standard pipes. The efficiency of the separator has been determined in an industrial scale, pilot plant test facility at CC Technologies in 4-inch diameter pipes and has been found to be in excess of 98-99% for the removal of sand. Two phase oil/water separation effectiveness is in excess of 90% in 1-stage and 95% in 2 - stage. (author)

  16. Greenhouse gas emission and exergy analyses of an integrated trigeneration system driven by a solid oxide fuel cell

    International Nuclear Information System (INIS)

    Chitsaz, Ata; Mahmoudi, S. Mohammad S.; Rosen, Marc A.

    2015-01-01

    Exergy and greenhouse gas emission analyses are performed for a novel trigeneration system driven by a solid oxide fuel cell (SOFC). The trigeneration system also consists of a generator-absorber heat exchanger (GAX) absorption refrigeration system and a heat exchanger to produce electrical energy, cooling and heating, respectively. Four operating cases are considered: electrical power generation, electrical power and cooling cogeneration, electrical power and heating cogeneration, and trigeneration. Attention is paid to numerous system and environmental performance parameters, namely, exergy efficiency, exergy destruction rate, and greenhouse gas emissions. A maximum enhancement of 46% is achieved in the exergy efficiency when the SOFC is used as the primary mover for the trigeneration system compared to the case when the SOFC is used as a standalone unit. The main sources of irreversibility are observed to be the air heat exchanger, the SOFC and the afterburner. The unit CO 2 emission (in kg/MWh) is considerably higher for the case in which only electrical power is generated. This parameter is reduced by half when the system is operates in a trigeneration mode. - Highlights: • A novel trigeneration system driven by a solid oxide fuel cell is analyzed. • Exergy and greenhouse gas emission analyses are performed. • Four special cases are considered. • An enhancement of up to 46% is achieved in exergy efficiency. • The CO 2 emission drops to a relatively low value for the tri-generation case

  17. Impact of operating conditions on performance of a novel gas double-dynamic solid-state fermentation bioreactor (GDSFB).

    Science.gov (United States)

    Chen, Hongzhang; Li, Yanjun; Xu, Fujian

    2013-11-01

    A self-designed novel solid-state fermentation (SSF) bioreactor named "gas double-dynamic solid-state fermentation bioreactor (GDSFB)" showed great success in processes for the production of several valuable products. For the present study, a simple GDSFB (2 L in volume) was designed to investigate the impact of exhaust time on SSF performance. Both air pressure and vent aperture significantly influenced the exhaust time. The production of cellulase by Penicillium decumbens JUA10 was studied in this bioreactor. When the vent aperture was maintained at 0.2 cm, the highest FPA activity of 17.2 IU/g dry solid-state medium was obtained at an air pressure of 0.2 MPa (gauge pressure). When the air pressure was maintained at 0.2 MPa, a vent aperture of 0.3 cm gave the highest FPA activity of 18.0 IU/g dry solid-state medium. Further analysis revealed that the exhaust time was a crucial indicator of good performance in GDSFB.

  18. Study of solid/liquid and solid/gas interfaces in Cu–isoleucine complex by surface X-ray diffraction

    International Nuclear Information System (INIS)

    Ferrer, Pilar; Rubio-Zuazo, Juan; Castro, German R.

    2013-01-01

    The enzymes could be understood like structures formed by amino acids bonded with metals, which act as active sites. The research on the coordination of metal–amino acid complexes will bring light on the behavior of metal enzymes, due to the close relation existing between the atomic structure and the functionality. The Cu–isoleucine bond is considered as a good model system to attain a better insight into the characteristics of naturally occurring copper metalloproteins. The surface structure of metal–amino acid complex could be considered as a more realistic model for real systems under biologic working conditions, since the molecular packing is decreased. In the surface, the structural constrains are reduced, keeping the structural capability of surface complex to change as a function of the surrounding environment. In this work, we present a surface X-ray diffraction study on Cu–isoleucine complex under different ambient conditions. Cu(Ile) 2 crystals of about 5 mm × 5 mm × 1 mm have been growth, by seeding method in a supersaturated solution, presenting a surface of high quality. The sample for the surface diffraction study was mounted on a cell specially designed for solid/liquid or solid/gas interface analysis. The Cu–isoleucine crystal was measured under a protective dry N 2 gas flow and in contact with a saturated metal amino acid solution. The bulk and the surface signals were compared, showing different atomic structures. In both cases, from surface diffraction data, it is observed that the atomic structure of the top layer undergoes a clear structural deformation. A non-uniform surface relaxation is observed producing an inhomogeneous displacement of the surface atoms towards the surface normal.

  19. Gas-solid heat exchange in a fibrous metallic material measured by a heat regenerator technique

    NARCIS (Netherlands)

    Golombok, M.; Jariwala, H.; Shirvill, C.

    1990-01-01

    The convective heat transfer properties of a porous metallic fibre material used in gas surface combustion burners are studied. The important parameter governing the heat transfer between hot gas and metal fibre—the heat transfer coefficient—is measured using a non-steady-state method based on

  20. A Simple Approach to Characterize Gas-Aqueous Liquid Two-phase Flow Configuration Based on Discrete Solid-Liquid Contact Electrification.

    Science.gov (United States)

    Choi, Dongwhi; Lee, Donghyeon; Kim, Dong Sung

    2015-10-14

    In this study, we first suggest a simple approach to characterize configuration of gas-aqueous liquid two-phase flow based on discrete solid-liquid contact electrification, which is a newly defined concept as a sequential process of solid-liquid contact and successive detachment of the contact liquid from the solid surface. This approach exhibits several advantages such as simple operation, precise measurement, and cost-effectiveness. By using electric potential that is spontaneously generated by discrete solid-liquid contact electrification, the configurations of the gas-aqueous liquid two-phase flow such as size of a gas slug and flow rate are precisely characterized. According to the experimental and numerical analyses on parameters that affect electric potential, gas slugs have been verified to behave similarly to point electric charges when the measuring point of the electric potential is far enough from the gas slug. In addition, the configuration of the gas-aqueous liquid two-phase microfluidic system with multiple gas slugs is also characterized by using the presented approach. For a proof-of-concept demonstration of using the proposed approach in a self-triggered sensor, a gas slug detector with a counter system is developed to show its practicality and applicability.

  1. Numerical Simulation of Gas-Solid Two-Phase Flow for Four-Channels Pulverized Swirling Burner

    Directory of Open Access Journals (Sweden)

    Defu LI

    2013-05-01

    Full Text Available This article presents a mathematical model of cold gas-solid two-phase flow which is based on the cement rotary kiln in service. By altering the parameters of air supply system of four- channels pulverized burner, investigations are taken of that motion trajectory and particle distributions in the very turbulent field. The results show that motion trail of most particles in rotary kiln is a combination process of gradual diffusion and slow sedimentation; increasing internal flow velocity would aggravate coal particles to diffuse; external flow velocity should be controlled in a reasonable range.

  2. Pilot-scale test on electron beam treatment of municipal solid waste flue gas with spraying slaked-lime slurry

    International Nuclear Information System (INIS)

    You Osada; Masahiro Sudo; Koichi Hirota

    1995-01-01

    Simultaneous removal of NO x , SO 2 and HCl in flue gas of a municipal solid waste incinerator was studied by using electron beam irradiation technology. The flue gas of around 1000 Nm 3 /h was led to a spray-dryer-type reactor from an inlet of ESP of the municipal waste incinerator by spraying slaked-lime slurry with one or more stoichiometric amount of the pollutants, concentrations of HCl (400 ppm) and SO 2 (50 ppm) decreased almost completely, while concentrations of NO x (100 ppm) were markedly decreased to about 20 ppm by electron beam irradiation with a dose of 10 kGy at 150 o C under spraying slaked-lime slurry of two stoichiometric amounts. The removal of NO x was improved by increasing the dose and the amount of spraying slaked-lime slurry, and by lowering of the irradiation temperature. (Author)

  3. Investigation into the determination of trimethylarsine in natural gas and its partitioning into gas and condensate phases using (cryotrapping)/gas chromatography coupled to inductively coupled plasma mass spectrometry and liquid/solid sorption techniques

    International Nuclear Information System (INIS)

    Krupp, E.M.; Johnson, C.; Rechsteiner, C.; Moir, M.; Leong, D.; Feldmann, J.

    2007-01-01

    Speciation of trialkylated arsenic compunds in natural gas, pressurized and stable condensate samples from the same gas well was performed using (Cryotrapping) Gas Chromatography-Inductively Coupled Plasma Mass Spectrometry. The major species in all phases investigated was found to be trimethylarsine with a highest concentration of 17.8 ng/L (As) in the gas phase and 33.2 μg/L (As) in the stable condensate phase. The highest amount of trimethylarsine (121 μg/L (As)) was found in the pressurized condensate, along with trace amounts of non-identified higher alkylated arsines. Volatile arsenic species in natural gas and its related products cause concern with regards to environment, safety, occupational health and gas processing. Therefore, interest lies in a fast and simple field method for the determination of volatile arsenicals. Here, we use simple liquid and solid sorption techniques, namely absorption in silver nitrate solution and adsorption on silver nitrate impregnated silica gel tubes followed by total arsenic determination as a promising tool for field monitoring of volatile arsenicals in natural gas and gas condensates. Preliminary results obtained for the sorption-based methods show that around 70% of the arsenic is determined with these methods in comparison to volatile arsenic determination using GC-ICP-MS. Furthermore, an inter-laboratory- and inter-method comparison was performed using silver nitrate impregnated silica tubes on 14 different gas samples with concentrations varying from below 1 to 1000 μg As/m 3 natural gas. The results obtained from the two laboratories differ in a range of 10 to 60%, but agree within the order of magnitude, which is satisfactory for our purposes

  4. A novel solid state fermentation coupled with gas stripping enhancing the sweet sorghum stalk conversion performance for bioethanol

    Science.gov (United States)

    2014-01-01

    Background Bioethanol production from biomass is becoming a hot topic internationally. Traditional static solid state fermentation (TS-SSF) for bioethanol production is similar to the traditional method of intermittent operation. The main problems of its large-scale intensive production are the low efficiency of mass and heat transfer and the high ethanol inhibition effect. In order to achieve continuous production and high conversion efficiency, gas stripping solid state fermentation (GS-SSF) for bioethanol production from sweet sorghum stalk (SSS) was systematically investigated in the present study. Results TS-SSF and GS-SSF were conducted and evaluated based on different SSS particle thicknesses under identical conditions. The ethanol yield reached 22.7 g/100 g dry SSS during GS-SSF, which was obviously higher than that during TS-SSF. The optimal initial gas stripping time, gas stripping temperature, fermentation time, and particle thickness of GS-SSF were 10 h, 35°C, 28 h, and 0.15 cm, respectively, and the corresponding ethanol stripping efficiency was 77.5%. The ethanol yield apparently increased by 30% with the particle thickness decreasing from 0.4 cm to 0.05 cm during GS-SSF. Meanwhile, the ethanol yield increased by 6% to 10% during GS-SSF compared with that during TS-SSF under the same particle thickness. The results revealed that gas stripping removed the ethanol inhibition effect and improved the mass and heat transfer efficiency, and hence strongly enhanced the solid state fermentation (SSF) performance of SSS. GS-SSF also eliminated the need for separate reactors and further simplified the bioethanol production process from SSS. As a result, a continuous conversion process of SSS and online separation of bioethanol were achieved by GS-SSF. Conclusions SSF coupled with gas stripping meet the requirements of high yield and efficient industrial bioethanol production. It should be a novel bioconversion process for bioethanol production from SSS

  5. In-situ study of the gas-phase composition and temperature of an intermediate-temperature solid oxide fuel cell anode surface fed by reformate natural gas

    Science.gov (United States)

    Santoni, F.; Silva Mosqueda, D. M.; Pumiglia, D.; Viceconti, E.; Conti, B.; Boigues Muñoz, C.; Bosio, B.; Ulgiati, S.; McPhail, S. J.

    2017-12-01

    An innovative experimental setup is used for in-depth and in-operando characterization of solid oxide fuel cell anodic processes. This work focuses on the heterogeneous reactions taking place on a 121 cm2 anode-supported cell (ASC) running with a H2, CH4, CO2, CO and steam gas mixture as a fuel, using an operating temperature of 923 K. The results have been obtained by analyzing the gas composition and temperature profiles along the anode surface in different conditions: open circuit voltage (OCV) and under two different current densities, 165 mA cm-2 and 330 mA cm-2, corresponding to 27% and 54% of fuel utilization, respectively. The gas composition and temperature analysis results are consistent, allowing to monitor the evolution of the principal chemical and electrochemical reactions along the anode surface. A possible competition between CO2 and H2O in methane internal reforming is shown under OCV condition and low current density values, leading to two different types of methane reforming: Steam Reforming and Dry Reforming. Under a current load of 40 A, the dominance of exothermic reactions leads to a more marked increase of temperature in the portion of the cell close to the inlet revealing that current density is not uniform along the anode surface.

  6. Study of gas-solid contact in an ultra-rapid reactor for cumene catalytic cracking; Etude du contact gaz-solide dans un reacteur a co-courant descendant par la mise en oeuvre du craquage catalytique du cumene

    Energy Technology Data Exchange (ETDEWEB)

    Bayle, J

    1996-11-05

    Few studies have been carried out on the notion of gas-solid contact in ultra-rapid reactors. Both gas and solid move in the reactor and the contact can be directly estimated when using a chemical reaction such as cumene cracking. It`s a pure and light feedstock whose kinetics can be determined in a fixed bed. The study was carried out on a downflow ultra-rapid reactor (ID = 20 mm, length = 1 m) at the University of Western Ontario. It proved that the quench and the ultra-rapid separation of gas and solid must be carefully designed in the pilot plant. Cumene conversion dropped when reducing gas-solid contact, which led to push the temperature over 550 deg. C and increase the cat/oil ratio at 25 working at solid mass fluxes below 85 kg/m{sup 2}.s. Change of selectivity at very short residence time were also observed due to deactivation effects. Experiments made by Roques (1994) with phosphorescent pigments on the Residence Time Distribution of solids gave Hydrodynamic data on a cold flow copy of the pilot plant. Experiments made on packed bed gave kinetic data on the cracking of cumene. These data were combined to optimize a mono dimensional plug flow model for cumene cracking. (author)

  7. Eulerian numerical simulation of gas-solid flows with several particles species; Modelisation numerique eulerienne des ecoulements gaz-solide avec plusieurs especes de particules

    Energy Technology Data Exchange (ETDEWEB)

    Patino-Palacios, G

    2007-11-15

    The simulation of the multiphase flows is currently an important scientific, industrial and economic challenge. The objective of this work is to improve comprehension via simulations of poly-dispersed flows and contribute the modeling and characterizing of its hydrodynamics. The study of gas-solid systems involves the models that takes account the influence of the particles and the effects of the collisions in the context of the momentum transfer. This kind of study is covered on the framework of this thesis. Simulations achieved with the Saturne-polyphasique-Tlse code, developed by Electricite de France and co-worked with the Institut de Mecanique des Fluides de Toulouse, allowed to confirm the feasibility of approach CFD for the hydrodynamic study of the injectors and dense fluidized beds. The stages of validation concern, on the one hand, the placement of the tool for simulation in its current state to make studies of validation and sensitivity of the models and to compare the numerical results with the experimental data. In addition, the development of new physical models and their establishments in the code Saturne will allow the optimization of the industrial process. To carry out this validation in a satisfactory way, a key simulation is made, in particular a monodisperse injection and the radial force of injection in the case of a poly-disperse flow, as well as the fluidization of a column made up of solid particles. In this last case, one approached three configurations of dense fluidized beds, in order to study the influence of the grid on simulations; then, one simulates the operation of a dense fluidized bed with which one characterizes the segregation between two various species of particles. The study of the injection of the poly-disperse flows presents two configurations; a flow Co-current gas-particle in gas (Case Hishida), and in addition, a poly-phase flow in a configuration of the jet type confined with zones of recirculation and stagnation (case

  8. Solid State Gas Sensor Research in Germany – a Status Report

    Directory of Open Access Journals (Sweden)

    Udo Weimar

    2009-06-01

    Full Text Available This status report overviews activities of the German gas sensor research community. It highlights recent progress in the field of potentiometric, amperometric, conductometric, impedimetric, and field effect-based gas sensors. It is shown that besides step-by-step improvements of conventional principles, e.g. by the application of novel materials, novel principles turned out to enable new markets. In the field of mixed potential gas sensors, novel materials allow for selective detection of combustion exhaust components. The same goal can be reached by using zeolites for impedimetric gas sensors. Operando spectroscopy is a powerful tool to learn about the mechanisms in n-type and in p-type conductometric sensors and to design knowledge-based improved sensor devices. Novel deposition methods are applied to gain direct access to the material morphology as well as to obtain dense thick metal oxide films without high temperature steps. Since conductometric and impedimetric sensors have the disadvantage that a current has to pass the gas sensitive film, film morphology, electrode materials, and geometrical issues affect the sensor signal. Therefore, one tries to measure directly the Fermi level position either by measuring the gas-dependent Seebeck coefficient at high temperatures or at room temperature by applying a modified miniaturized Kelvin probe method, where surface adsorption-based work function changes drive the drain-source current of a field effect transistor.

  9. Pressure dependence of emission intensity of rare-gas excimer light produced by silent discharge; Teikiatsu ryoiki ni okeru musei hoden reiki ki gas excimer hikari shutsuryoku no atsuryoku izonsei

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Y.; Tanaka, M.; Yukimura, K. [Doshisha University, Kyoto (Japan)

    1996-09-20

    To establish the pressure dependence of silent discharge excited rare gas excimer light emission, a vacua ultraviolet light was subjected to spectroscopic analysis at a pressure lower than 20kPa. Researches are under way to apply the discharge excited rare gas excimer lamp as a vacuum ultraviolet light source for the development of new materials and for the conservation of environments. When the pressure is as low as 1.8kPa or 4.4kPa, the emission has peaks at wavelengths centering on 147nm and 149nm, both of which are the resonance lines of the xenon atom. Excimer generation becomes prominent as the pressure increases, with the second continuum of light growing dominant at 35kPa to weaken relatively the resonance lines and the first continuum of light. In the first continuum, emission increases only at a suppressed rate, as compared with emission in the second continuum, due for instance to a collision caused relaxation process in which excimers are lost. In the case of xenon in the vicinity of 10-11kPa, the first continuum of light and the second continuum of light are approximately equal in emission intensity, producing a vacuum ultraviolet light source with a bandwidth relatively large for a single gas spectrum. 14 refs., 11 figs.

  10. Magnesium hydroxide extracted from a magnesium-rich mineral for CO2 sequestration in a gas-solid system.

    Science.gov (United States)

    Lin, Pao-Chung; Huang, Cheng-Wei; Hsiao, Ching-Ta; Teng, Hsisheng

    2008-04-15

    Magnesium hydroxide extracted from magnesium-bearing minerals is considered a promising agent for binding CO2 as a carbonate mineral in a gas-solid reaction. An efficient extraction route consisting of hydrothermal treatment on serpentine in HCl followed by NaOH titration for Mg(OH)2 precipitation was demonstrated. The extracted Mg(OH)2 powder had a mean crystal domain size as small as 12 nm and an apparent surface area of 54 m2/g. Under one atmosphere of 10 vol% CO2/N2, carbonation of the serpentine-derived Mg(OH)2 to 26% of the stoichiometric limit was achieved at 325 degrees C in 2 h; while carbonation of a commercially available Mg(OH)2, with a mean crystal domain size of 33 nm and an apparent surface area of 3.5 m2/g, reached only 9% of the stoichiometric limit. The amount of CO2 fixation was found to be inversely proportional to the crystal domain size of the Mg(OH)2 specimens. The experimental data strongly suggested that only a monolayer of carbonates was formed on the crystal domain boundary in the gas-solid reaction, with little penetration of the carbonates into the crystal domain.

  11. Oxidation of nitrobenzene by ozone in the presence of faujasite zeolite in a continuous flow gas-liquid-solid reactor.

    Science.gov (United States)

    Reungoat, J; Pic, J S; Manéro, M H; Debellefontaine, H

    2010-01-01

    This work investigates the oxidation of nitrobenzene (NB) by ozone in the presence of faujasite zeolite. Experiments were carried out in a gas-liquid-solid reactor were ozone transfer and NB oxidation took place at the same time. Three configurations of the reactor were compared: empty, filled with inert glass beads and filled with faujasite pellets. First, ozone transfer coefficient (k(L)a) and decomposition rate constant (k(C)) were determined for each configuration. In presence of solid, k(L)a was 2.0 to 2.6 times higher and k(C) was 5.0 to 6.4 times higher compared to the empty reactor. Then, the various configurations were evaluated in terms of NB removal and chemical oxygen demand (COD) decrease. The faujasite reactor showed higher removal of NB and decrease of COD compared to other configurations under the same conditions suggesting that the faujasite increases the oxidation rate of NB. Oxidation of NB in presence of faujasite also proved to be limited by the transfer of ozone from the gas to the liquid phase.

  12. Probe into Environmental Kuznets Characteristics and Causes of Wastewater,Waste Gas, and Solid Wastes in Wuhan City

    Institute of Scientific and Technical Information of China (English)

    刘耀彬; 李仁东

    2004-01-01

    Environmental Kuznets characteristics and causes of waste water, waste gas, and solid wastes in Wuhan city was researched; By comparing the variation of "three wastes", i.e. waste water, waste gas, and solid wastes, the model between standardized per capita GDP and values of "three wastes" discharge was established and the causes were analyzed based on the theory of environmental economics. The results show that 1) the total amount is fluctuantly increasing, but the discharges of the three kinds are temporarily different, 2) the curve conforms to the three-power function, in which the curve descends from 1985 to 1994, and the curve preliminary shows the environmental Kuznets characteristics from 1995 to 2001, 3) the simulated calculation illustrates that the turning point of this environmental Kuznets curve would be over 25007.25 Yuan per caprta, and 4) the economic development, changing of industry structure, energy resource structure, and environmental policies are the main factors leading to the Environmental Kuznets Curve in Wuhan city.

  13. Direct gas-solid carbonation of serpentinite residues in the absence and presence of water vapor: a feasibility study for carbon dioxide sequestration.

    Science.gov (United States)

    Veetil, Sanoopkumar Puthiya; Pasquier, Louis-César; Blais, Jean-François; Cecchi, Emmanuelle; Kentish, Sandra; Mercier, Guy

    2015-09-01

    Mineral carbonation of serpentinite mining residue offers an environmentally secure and permanent storage of carbon dioxide. The strategy of using readily available mining residue for the direct treatment of flue gas could improve the energy demand and economics of CO2 sequestration by avoiding the mineral extraction and separate CO2 capture steps. The present is a laboratory scale study to assess the possibility of CO2 fixation in serpentinite mining residues via direct gas-solid reaction. The degree of carbonation is measured both in the absence and presence of water vapor in a batch reactor. The gas used is a simulated gas mixture reproducing an average cement flue gas CO2 composition of 18 vol.% CO2. The reaction parameters considered are temperature, total gas pressure, time, and concentration of water vapor. In the absence of water vapor, the gas-solid carbonation of serpentinite mining residues is negligible, but the residues removed CO2 from the feed gas possibly due to reversible adsorption. The presence of small amount of water vapor enhances the gas-solid carbonation, but the measured rates are too low for practical application. The maximum CO2 fixation obtained is 0.07 g CO2 when reacting 1 g of residue at 200 °C and 25 barg (pCO2 ≈ 4.7) in a gas mixture containing 18 vol.% CO2 and 10 vol.% water vapor in 1 h. The fixation is likely surface limited and restricted due to poor gas-solid interaction. It was identified that both the relative humidity and carbon dioxide-water vapor ratio have a role in CO2 fixation regardless of the percentage of water vapor.

  14. In-situ UV-Visible and Raman spectroscopy for gas-liquid-solid systems

    NARCIS (Netherlands)

    Stemmet, C.P.; Schouten, J.C.; Nijhuis, T.A.

    2009-01-01

    This paper presents the use of UV-vis and Raman spectroscopy to measure the state of a solid in a multiphase reactor. A slurry of particles and a packed bubble column were used. As this study is a proof of principle a model for an active catalyst system, insoluble pH indicators deposited on the

  15. In situ UV-Vis spectroscopy in gas-liquid-solid systems

    NARCIS (Netherlands)

    Stemmet, C.P.; Schouten, J.C.; Nijhuis, T.A.

    2010-01-01

    This paper presents the use of ultraviolet-visible spectroscopy (UV-Vis) spectroscopy in a slurry of particles, a packed bubble column, and a trickle bed to assess the changes in the state of an active component on the surface of the solid support. As a model system, insoluble pH indicators

  16. In Situ Insight into Reversible O2 Gas-Solid Reactions

    DEFF Research Database (Denmark)

    Wegeberg, Christina

    2016-01-01

    Non-porous crystalline solids containing a series of cationic tetracobalt complexes reversibly, selectively and stoichiometrically chemisorb dioxygen in temperature/O2 partial pressure induced processes involving the oxidation of cobalt with concurrent reduction of two equivalents of sorbed O2 to...

  17. Modeling of vapor-liquid-solid equilibrium in gas - aqueous electrolyte systems

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Rasmussen, Peter

    1999-01-01

    A thermodynamic model for the description of vapor-liquid-solid equilibria is introduced. This model is a combination of the extended UNIQUAC model for electrolytes and the Soave-Redlich-Kwong cubic equation of state. The model has been applied to aqueous systems containing ammonia and/or carbon ...

  18. Development of gas-solid direct contact heat exchanger by use of axial flow cyclone

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Akihiko; Yokomine, Takehiko [Kyushu University (Japan). Interdisciplinary Graduate School of Engineering Sciences; Nagafuchi, Tatsuro [Miura Co. Ltd., Matsuyamashi (Japan)

    2004-10-01

    A heat exchanger between particulate or granular materials and gas is developed. It makes use of a swirling gas flow similar to the usual cyclone separators but the difference from them is that the swirl making gas is issued into the cyclone chamber with downward axial velocity component. After it turns the flow direction near the bottom of the chamber, the low temperature gas receives heat from high temperature particles supplied from above at the chamber's center. Through this configuration, a direct contact and quasi counter-flow heat exchange pattern is realized so that the effective recovery of heat carried by particles is achieved. A model heat exchanger was manufactured via several numerical experiments and its performances of heat exchange as well as particle recovery were examined. Attaching a small particle diffuser below the particle-feeding nozzle brought about a drastic improvement of the heat exchange performance without deteriorating the particle recovery efficiency. The outlet gas temperature much higher than the particle outlet temperature was finally obtained, which is never realized in the parallel flow heat exchanger. (author)

  19. Solid-State Gas Adsorption Studies with Discrete Palladium(II) [Pd2 (L)4 ]4+ Cages.

    Science.gov (United States)

    Preston, Dan; White, Keith F; Lewis, James E M; Vasdev, Roan A S; Abrahams, Brendan F; Crowley, James D

    2017-08-04

    The need for effective CO 2 capture systems remains high, and due to their tunability, metallosupramolecular architectures are an attractive option for gas sorption. While the use of extended metal organic frameworks for gas adsorption has been extensively explored, the exploitation of discrete metallocage architectures to bind gases remains in its infancy. Herein the solid state gas adsorption properties of a series of [Pd 2 (L) 4 ] 4+ lantern shaped coordination cages (L = variants of 2,6-bis(pyridin-3-ylethynyl)pyridine), which had solvent accessible internal cavities suitable for gas binding, have been investigated. The cages showed little interaction with dinitrogen gas but were able to take up CO 2 . The best performing cage reversibly sorbed 1.4 mol CO 2 per mol cage at 298 K, and 2.3 mol CO 2 per mol cage at 258 K (1 bar). The enthalpy of binding was calculated to be 25-35 kJ mol -1 , across the number of equivalents bound, while DFT calculations on the CO 2 binding in the cage gave ΔE for the cage-CO 2 interaction of 23-28 kJ mol -1 , across the same range. DFT modelling suggested that the binding mode is a hydrogen bond between the carbonyl oxygen of CO 2 and the internally directed hydrogen atoms of the cage. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. New paradigm for simplified combustion modeling of energetic solids: Branched chain gas reaction

    Energy Technology Data Exchange (ETDEWEB)

    Brewster, M.Q.; Ward, M.J. [Univ. of Illinois, Urbana, IL (United States); Son, S.F. [Los Alamos National Lab., NM (United States)

    1997-09-01

    Two combustion models with simple but rational chemistry are compared: the classical high gas activation energy (E{sub g}/RT {much_gt} 1) Denison-Baum-Williams (DBW) model, and a new low gas activation energy (E{sub g}/RT {much_lt} 1) model recently proposed by Ward, Son, and Brewster (WSB). Both models make the same simplifying assumptions of constant properties, Lewis number unity, single-step, second order gas phase reaction, and single-step, zero order, high activation energy condensed phase decomposition. The only difference is in the gas reaction activation energy E{sub g} which is asymptotically large for DBW and vanishingly small for WSB. For realistic parameters the DBW model predicts a nearly constant temperature sensitivity {sigma}{sub p} and a pressure exponent n approaching 1. The WSB model predicts generally observed values of n = 0.7 to 0.9 and {sigma}{sub p}(T{sub o},P) with the generally observed variations with temperature (increasing) and pressure (decreasing). The WSB temperature profile also matches measured profiles better. Comparisons with experimental data are made using HMX as an illustrative example (for which WSB predictions for {sigma}{sub p}(T{sub o},P) are currently more accurate than even complex chemistry models). WSB has also shown good agreement with NC/NG double base propellant and HNF, suggesting that at the simplest level of combustion modeling, a vanishingly small gas activation energy is more realistic than an asymptotically large one. The authors conclude from this that the important (regression rate determining) gas reaction zone near the surface has more the character of chain branching than thermal decomposition.

  1. Composite beryllium-ceramics breeder pin elements for a gas cooled solid blanket

    International Nuclear Information System (INIS)

    Carre, F.; Chevreau, G.; Gervaise, F.; Proust, E.

    1986-06-01

    Helium coolant have main advantages compared to water for solid blankets. But limitations exist too and the development of attractive helium cooled blankets based on breeder pin assemblies has been essentially made possible by the derivation from recent CEA neutronic studies of an optimized composite beryllium/ceramics breeder arrangement. Description of the proposed toroidal blanket layout for Net is made together with the analysis of its main performance. Merits of the considered composite Be/ceramics breeder elements are discussed

  2. Performance Comparison on Repowering of a Steam Power Plant with Gas Turbines and Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2016-01-01

    Repowering is a process for transforming an old power plant for greater capacity and/or higher efficiency. As a consequence, the repowered plant is characterized by higher power output and less specific CO2 emissions. Usually, repowering is performed by adding one or more gas turbines into an exi......Repowering is a process for transforming an old power plant for greater capacity and/or higher efficiency. As a consequence, the repowered plant is characterized by higher power output and less specific CO2 emissions. Usually, repowering is performed by adding one or more gas turbines...... into an existing steam cycle which was built decades ago. Thus, traditional repowering results in combined cycles (CC). High temperature fuel cells (such as solid oxide fuel cell (SOFC)) could also be used as a topping cycle, achieving even higher global plant efficiency and even lower specific CO2 emissions....... Decreasing the operating temperature in a SOFC allows the use of less complex materials and construction methods, consequently reducing plant and the electricity costs. A lower working temperature makes it also suitable for topping an existing steam cycle, instead of gas turbines. This is also the target...

  3. Numerical simulation of coupled binary gas-solid interaction during carbon dioxide sequestration in a coal bed

    International Nuclear Information System (INIS)

    Feng Qiyan; Zhou Lai; Chen Zhongwei; Liu Jishan

    2008-01-01

    Complicated coupled binary gas-solid interaction arises during carbon dioxide sequestration in a coal seam, which combines effects of CO 2 -CH 4 counter adsorption, CO 2 -CH 4 counter diffusion, binary gas flow and coal bed deformation. Through solving a set of coupled field governing equations, a novel full coupled Finite Element (FE) model was established by COMSOL Multiphysics. The new FE model was applied to the quantification of coal porous pressure, coal permeability, gas composition fraction and coal displacement when CO 2 was injected in a CH 4 saturated coal bed. Numerical results demonstrate that CH 4 is swept by the injected CO 2 accompanied by coal volumetric deformation. Compared to the single CH 4 in situ, CH 4 -CO 2 counter-diffusion induced coal swelling can make more compensation for coal shrinkage due to effective stress. Competing influences between the effective stress and the CH 4 -CO 2 counter-diffusion induced volume change governs the evolution of porous pressure and permeability, which is controlled by the porous pressure correspondingly. This achievement extends our ability to understand the coupled multi-physics of the CO 2 geological sequestration and CO 2 enhanced coal bed methane recovery under field conditions. (authors)

  4. Efficiency of energy recovery from municipal solid waste and the resultant effect on the greenhouse gas balance.

    Science.gov (United States)

    Gohlke, Oliver

    2009-11-01

    Global warming is a focus of political interest and life-cycle assessment of waste management systems reveals that energy recovery from municipal solid waste is a key issue. This paper demonstrates how the greenhouse gas effects of waste treatment processes can be described in a simplified manner by considering energy efficiency indicators. For evaluation to be consistent, it is necessary to use reasonable system boundaries and to take the generation of electricity and the use of heat into account. The new European R1 efficiency criterion will lead to the development and implementation of optimized processes/systems with increased energy efficiency which, in turn, will exert an influence on the greenhouse gas effects of waste management in Europe. Promising technologies are: the increase of steam parameters, reduction of in-plant energy consumption, and the combined use of heat and power. Plants in Brescia and Amsterdam are current examples of good performance with highly efficient electricity generation. Other examples of particularly high heat recovery rates are the energy-from-waste (EfW) plants in Malmö and Gothenburg. To achieve the full potential of greenhouse gas reduction in waste management, it is necessary to avoid landfilling combustible wastes, for example, by means of landfill taxes and by putting incentives in place for increasing the efficiency of EfW systems.

  5. Possibilities of Mercury Removal in the Dry Flue Gas Cleaning Lines of Solid Waste Incineration Units

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Karel; Hartman, Miloslav; Šyc, Michal; Pohořelý, Michael; Kameníková, Petra; Jeremiáš, Michal; Durda, Tomáš

    2016-01-01

    Roč. 166, JAN 15 (2016), s. 499-511 ISSN 0301-4797 R&D Projects: GA TA ČR TE02000236 Institutional support: RVO:67985858 Keywords : waste incineration * mercury removal * flue gas Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 4.010, year: 2016

  6. Computational fluid dynamics for dense gas-solid fluidized beds: a multi-scale modeling strategy

    NARCIS (Netherlands)

    Hoef, van der M.A.; Sint Annaland, van M.; Kuipers, J.A.M.

    2005-01-01

    Dense gas-particle flows are encountered in a variety of industrially important processes for large scale production of fuels, fertilizers and base chemicals. The scale-up of these processes is often problematic and is related to the intrinsic complexities of these flows which are unfortunately not

  7. Modeling bubble heat transfer in gas-solid fluidized beds using DEM

    NARCIS (Netherlands)

    Patil, A.V.; Peters, E.A.J.F.; Kolkman, T.; Kuipers, J.A.M.

    2014-01-01

    Discrete element method (DEM) simulations of a pseudo 2-D fluidized bed at non-isothermal conditions are presented. First implementation details are discussed. This is followed by a validation study where heating of a packed column by a flow of heated fluid is considered. Next hot gas injected into

  8. The gas/solid methane abundance ratio toward deeply embedded protostars

    NARCIS (Netherlands)

    Boogert, ACA; Helmich, EP; van Dishoeck, EF; Schutte, WA

    1998-01-01

    We present the detection of re-vibrational absorption lines of the deformation mode of gaseous CH4 toward the massive protostars W 33A, and NGC 7538 : IRS9, using the SWS spectrometer an board of the Infrared Space Observatory. The observed lines indicate that the CH4 gas is warm (T similar to N 90

  9. A Gas-Solid Singlet Delta Oxygen Generator for the Chemical Iodine Laser

    National Research Council Canada - National Science Library

    Alfano, Angelo

    2002-01-01

    ... at 1.27 microns by passing chlorine gas through aqueous, basic hydrogen peroxide (H2O2/OH). Unfortunately, the process of nonradiative relaxation used in COIL results in the creation of undesired heat and not the desired light emission...

  10. Sulfur Poisoning of the Water Gas Shift Reaction on Anode Supported Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Hagen, Anke

    2013-01-01

    resistance increased both in the high and low frequency region, which indicates a strong poisoning of the water gas shift reaction and thus a lack of hydrogen fuel in addition to the poisoning of the electrochemical hydrogen oxidation. All poisoning effects are reversible under the applied operating...

  11. The role of clusters in gas-solids reactors. An experimental study.

    NARCIS (Netherlands)

    Venderbosch, R.H.

    1998-01-01

    This PhD-work is meant to determine the contact efficiency experimentally for fluidization of fine particles over a wide range of superficial gas velocities (dp<200 mm and 0.1

  12. Solid particle effects on heat transfer in a multi-layered molten pool with gas injection

    International Nuclear Information System (INIS)

    Bilbao y Leon, Rosa Marina; Corradini, Michael L.

    2006-01-01

    In the very unlikely event of a severe reactor accident involving core melt and pressure vessel failure, it is important to identify the circumstances that would allow the molten core material to cool down and resolidify, bringing core debris to a stable coolable state. To achieve this, it has been proposed to flood the cavity with water from above forming a layered structure where upward heat loss from the molten pool to the water will cause the core material to quench and solidify. In this situation the molten pool would become a three-phase mixture: e.g., a solid and liquid slurry formed by the molten pool as it cools to a temperature below the temperature of liquidus, agitated by the gases formed in the concrete ablation process. The present work quantifies the partition of the heat losses upward and downward in this multi-layered configuration, considering the influence of the viscosity and the solid fraction in the pool, from test data obtained from intermediate scale experiments at the University of Wisconsin-Madison. These experimental results show heat transfer behavior for multi-layered pools for a range of viscosities and solid fractions. These results are compared to previous experimental studies and well known correlations and models

  13. Volatile organic compound adsorption in a gas-solid fluidized bed.

    Science.gov (United States)

    Ng, Y L; Yan, R; Tsen, L T S; Yong, L C; Liu, M; Liang, D T

    2004-01-01

    Fluidization finds many process applications in the areas of catalytic reactions, drying, coating, combustion, gasification and microbial culturing. This work aims to compare the dynamic adsorption characteristics and adsorption rates in a bubbling fluidized bed and a fixed bed at the same gas flow-rate, gas residence time and bed height. Adsorption with 520 ppm methanol and 489 ppm isobutane by the ZSM-5 zeolite of different particle size in the two beds enabled the differentiation of the adsorption characteristics and rates due to bed type, intraparticle mass transfer and adsorbate-adsorbent interaction. Adsorption of isobutane by the more commonly used activated carbon provided the comparison of adsorption between the two adsorbent types. With the same gas residence time of 0.79 seconds in both the bubbling bed and fixed bed of the same bed size of 40 mm diameter and 48 mm height, the experimental results showed a higher rate of adsorption in the bubbling bed as compared to the fixed bed. Intraparticle mass transfer and adsorbent-adsorbate interaction played significant roles in affecting the rate of adsorption, with intraparticle mass transfer being more dominant. The bubbling bed was observed to have a steeper decline in adsorption rate with respect to increasing outlet concentration compared to the fixed bed. The adsorption capacities of zeolite for the adsorbates studied were comparatively similar in both beds; fluidizing, and using smaller particles in the bubbling bed did not increase the adsorption capacity of the ZSM-5 zeolite. The adsorption capacity of activated carbon for isobutane was much higher than the ZSM-5 zeolite for isobutane, although at a lower adsorption rate. Fourier transform infra-red (FTIR) spectroscopy was used as an analytical tool for the quantification of gas concentration. Calibration was done using a series of standards prepared by in situ dilution with nitrogen gas, based on the ideal gas law and relating partial pressure to gas

  14. The causes of the municipal solid waste and the greenhouse gas emissions from the waste sector in the United States.

    Science.gov (United States)

    Lee, Seungtaek; Kim, Jonghoon; Chong, Wai K O

    2016-10-01

    The United States generated approximately 730kg of waste per capita in 2013, which is the highest amount of waste among OECD countries. The waste has adverse effects to human health and the environment. One of the most serious adverse effects is greenhouse gas emissions, especially methane (CH4), which causes global warming. However, the United States' amount of waste generation is not decreasing, and the recycling rate is only 26%, which is lower than other OECD countries. In order to decrease waste generation and greenhouse gas emissions, identifying the causality of the waste generation and greenhouse gas emissions from waste sector should be made a priority. The research objective is to verify whether the Environmental Kuznets Curve relationship is supported for waste generation and GDP across the U.S. Moreover, it also confirmed that total waste generation and recycling of waste influences carbon dioxide emissions from the waste sector. Based on the results, critical insight and suggestions were offered to policymakers, which is the potential way to lower the solid waste and greenhouse gas emissions from the waste sector. This research used annually based U.S. data from 1990 to 2012, and these data were collected from various data sources. To verify the causal relationship, the Granger causality test was applied. The results showed that there is no causality between GDP and waste generation, but total waste and recycling generate significantly increasing and decreasing greenhouse gas emissions from the waste sector, respectively. This implies that waste generation will not decrease even if GDP increases. And, if waste generation decreases or the recycling rate increases, greenhouse gas emission will decrease. Based on these results, increasing the recycling rate is first suggested. The second suggestion is to break the causal relationship between MSW and greenhouse gas emission from the waste sector. The third is that the U.S. government should benchmark a

  15. Complex plasmochemical processing of solid fuel

    Directory of Open Access Journals (Sweden)

    Vladimir Messerle

    2012-12-01

    Full Text Available Technology of complex plasmaochemical processing of solid fuel by Ecibastuz bituminous and Turgay brown coals is presented. Thermodynamic and experimental study of the technology was fulfilled. Use of this technology allows producing of synthesis gas from organic mass of coal and valuable components (technical silicon, ferrosilicon, aluminum and silicon carbide and microelements of rare metals: uranium, molybdenum, vanadium etc. from mineral mass of coal. Produced a high-calorific synthesis gas can be used for methanol synthesis, as high-grade reducing gas instead of coke, as well as energy gas in thermal power plants.

  16. Mass spectrometrical study of rare gas compositions and neutron capture effects in Yamato-74191 (L 3) Chondrite

    International Nuclear Information System (INIS)

    Takaoka, N.; Nagao, K.

    1980-01-01

    The unequilibrated hypersthene chondrite Yamato-74191 was studied mass spectrometrically for rare gases released at various temperatures. Cosmogenic gases dominate in He and Ne. The meteorite contains large amounts of trapped Ar, Kr and Xe, and radiogenic 40 Ar and 129 Xe. Cosmic-ray irradiation and K-Ar ages were determined. In addition to spallogenic components of Kr and Xe, isotopic excesses of 8 sup(O)Kr, 82 Kr, 128 Xe and 126 Xe relative to AVCC-Kr and -Xe were found. The ratio of 80 Kr-excess to 82 Kr-excess is 2.66 after correction for spallogenic Kr. A correlation between 128 Xe/ 132 Xe and 129 Xe/ 132 Xe was found. The 129 Xe/ 132 Xe ratio for trapped Xe in Yamato-74191 was determined as 1.12 +- 0.29 with the correlation plot. The excesses found in Yamato-74191 are best explained by epithermal neutron capture on Br and I, and by the 127 I(n,2nβ) 126 Xe reaction. Using neutron-produced 80 Kr, the neutron slowing-down density was estimated to be 0.14 +- 0.03 cm -3 sec -1 . A minimum mass and a preatmospheric radius was estimated to be 470 kg and 32 cm, respectively. (orig.)

  17. VUV emission spectra from binary rare gas mixtures near the resonance lines of Xe I and Kr I

    CERN Document Server

    Morozov, A; Gerasimov, G; Arnesen, A; Hallin, R

    2003-01-01

    Emission spectra of Xe-X (X = He, Ne, Ar and Kr) and of Kr-Y (Y = He, Ne and Ar) mixtures with low concentrations of the heavier gases (0.1-1%) and moderate total pressures (50-200 hPa) have been recorded near each of the two resonance lines of Xe and Kr in DC glow capillary discharges. The recorded intense emissions have narrow spectral profiles with FWHM of about 0.1 nm. The profiles are very similar in shape to profiles of known high resolution absorption spectra recorded at comparable gas pressures. A tentative identification of the emission structures is given, which involves transitions in heteronuclear molecules and quasimolecules between weakly-bound states.

  18. Coherent and non coherent atom optics experiment with an ultra-narrow beam of metastable rare gas atoms; Experiences d'optique atomique coherente ou non avec un jet superfin d'atomes metastables de gaz rares

    Energy Technology Data Exchange (ETDEWEB)

    Grucker, J

    2007-12-15

    In this thesis, we present a new type of atomic source: an ultra-narrow beam of metastable atoms produced by resonant metastability exchange inside a supersonic beam of rare gas atoms. We used the coherence properties of this beam to observe the diffraction of metastable helium, argon and neon atoms by a nano-transmission grating and by micro-reflection-gratings. Then, we evidenced transitions between Zeeman sublevels of neon metastable {sup 3}P{sub 2} state due to the quadrupolar part of Van der Waals potential. After we showed experimental proofs of the observation of this phenomenon, we calculated the transition probabilities in the Landau - Zener model. We discussed the interest of Van der Waals - Zeeman transitions for atom interferometry. Last, we described the Zeeman cooling of the supersonic metastable argon beam ({sup 3}P{sub 2}). We have succeeded in slowing down atoms to speeds below 100 m/s. We gave experimental details and showed the first time-of-flight measurements of slowed atoms.

  19. Abundance and Utility: For Military Operations, Liquid Fuels Remain a Solid Choice over Natural Gas

    Science.gov (United States)

    2014-08-01

    GTL plants in the world (two in both Malaysia and Qatar and one in South Africa). As recent developments are increasing the supply of natural gas...SUPPLEMENTARY NOTES The article (likely in cleaner form) will eventually be posted online at: http://www.tacticaldefensemedia.com/archive/dod_power.php The...there are approximately 1,400 CNG and 100 LNG (public and private) refueling stations, compared to about 150,000 retail fueling stations. While

  20. Novel Solid Encapsulation of Ethylene Gas Using Amorphous α-Cyclodextrin and the Release Characteristics.

    Science.gov (United States)

    Ho, Binh T; Bhandari, Bhesh R

    2016-05-04

    This research investigated the encapsulation of ethylene gas into amorphous α-cyclodextrins (α-CDs) at low (LM) and high (HM) moisture contents at 1.0-1.5 MPa for 24-120 h and its controlled release characteristics at 11.2-52.9% relative humidity (RH) for 1-168 h. The inclusion complexes (ICs) were characterized using X-ray diffractometry (XRD), nuclear magnetic resonance spectroscopy (CP-MAS (13)C NMR), and scanning electron microscopy (SEM). Ethylene concentrations in the ICs were from 0.45 to 0.87 mol of ethylene/mol CD and from 0.42 to 0.54 mol of ethylene/mol CD for LM and HM α-CDs, respectively. Ethylene gas released from the encapsulated powder at higher rates with increasing RH. An analysis of release kinetics using Avrami's equation showed that the LM and HM amorphous α-CDs were not associated with significant differences in release constant k and parameter n for any given RH condition. NMR spectra showed the presence of the characteristic carbon-carbon double bond of ethylene gas in the encapsulated α-CD powder.

  1. Automated solid-phase extraction of herbicides from water for gas chromatographic-mass spectrometric analysis

    Science.gov (United States)

    Meyer, M.T.; Mills, M.S.; Thurman, E.M.

    1993-01-01

    An automated solid-phase extraction (SPE) method was developed for the pre-concentration of chloroacetanilide and triazine herbicides, and two triazine metabolites from 100-ml water samples. Breakthrough experiments for the C18 SPE cartridge show that the two triazine metabolites are not fully retained and that increasing flow-rate decreases their retention. Standard curve r2 values of 0.998-1.000 for each compound were consistently obtained and a quantitation level of 0.05 ??g/l was achieved for each compound tested. More than 10,000 surface and ground water samples have been analyzed by this method.

  2. Sensing sulfur oxides and other sulfur bearing pollutants with solid electrolyte pellets. I. Gas concentration cells

    Energy Technology Data Exchange (ETDEWEB)

    Chamberland, A M; Gauthier, J M

    1977-01-01

    A new sensing technique using a solid electrolyte has been demonstrated for sulfur-bearing pollutants. Based on potentiometric measurements across a pellet of potassium sulfate, this sensor allows concentrations of sulfur dioxides, sulfur trioxide, hydrogen sulfide, methyl mercaptan and carbonyl sulfide in air to be measured with accuracy. Its operational concentration range at the present time is 0.1 ppM up to at least 10,000 ppM. The presence of other common pollutants such as carbon dioxide, methane, nitric oxide and nitrogen dioxide does not interfere with the measurement of air samples containing sulfur-bearing pollutants.

  3. The wetting of planar solid surfaces by symmetric binary mixtures near bulk gas-liquid coexistence

    International Nuclear Information System (INIS)

    Woywod, Dirk; Schoen, Martin

    2004-01-01

    We investigate the wetting of planar, nonselective solid substrates by symmetric binary mixtures where the attraction strength between like molecules of components A and B is the same, that is ε AA ε BB AB vertical bar ≤ vertical bar ε AA vertical bar, that is by varying the attraction between a pair of unlike molecules. By means of mean-field lattice density functional calculations we observe a rich wetting behaviour as a result of the interplay between ε AB and the attraction of fluid molecules by the solid substrate ε W . In accord with previous studies we observe complete wetting only above the critical end point if the bulk mixture exhibits a moderate to weak tendency to liquid-liquid phase separation even for relatively strong fluid-substrate attraction. However, in this case layering transitions may arise below the temperature of the critical end point. For strongly phase separating mixtures complete wetting is observed for all temperatures T ≥0 along the line of discontinuous phase transitions in the bulk

  4. Combustible gas production (methane) and biodegradation of solid and liquid mixtures of meat industry wastes

    Energy Technology Data Exchange (ETDEWEB)

    Marcos, A.; Al-Kassir, A.; Cuadros, F.; Lopez-Rodriguez, F. [School of Engineering, University of Extremadura, Avda. De Elva, s/n, 06071, Badajoz (Spain); Mohamad, A.A. [Department of Mechanical and Manufacturing Engineering, University of Calgary, 2500 University Dr. N.W., Calgary, Alberta (Canada)

    2010-05-15

    This work is devoted to determine the optimal operational conditions on the methane production as well as on the biodegradation obtained from the anaerobic codigestion of solid (fat, intestines, rumen, bowels, whiskers, etc.) and liquid (blood, washing water, manure, etc.) wastes of meat industry, particularly the ones rising from the municipal slaughterhouse of Badajoz (Spain). The experiments were performed using a 2 l capacity discontinuous digester at 38 C. The loading rate were 0.5, 1, 2, 3, and 4.5 g COD for wastewater (washing water and blood; Mixture 1), and 0.5, 1, 2, 3, and 4 g COD for the co-digestion of a mixture of 97% liquid effluent and 3% solid wastes v/v (Mixture 2) which represents the annual mean composition of the waste generated by the slaughterhouse. The maximal biodegradation rates obtained were: Mixture 1, 56.9% for a COD load of 1 g; and Mixture 2, 19.1% for a COD load of 2 g. For both mixtures, the greatest methane production was for the maximum COD load (4.5 g for Mixture 1, and 4 g for Mixture 2), at which values the amounts of methane obtained during and at the end of the co-digestion were practically indistinguishable between the two mixtures. The results will be used to design, construct, and establish the optimal operating conditions of a continuous complete-mixture biodigester. (author)

  5. The impact of municipal solid waste treatment methods on greenhouse gas emissions in Lahore, Pakistan.

    Science.gov (United States)

    Batool, Syeda Adila; Chuadhry, Muhammad Nawaz

    2009-01-01

    The contribution of existing municipal solid waste management to emission of greenhouse gases and the alternative scenarios to reduce emissions were analyzed for Data Ganj Bukhsh Town (DGBT) in Lahore, Pakistan using the life cycle assessment methodology. DGBT has a population of 1,624,169 people living in 232,024 dwellings. Total waste generated is 500,000 tons per year with an average per capita rate of 0.84kg per day. Alternative scenarios were developed and evaluated according to the environmental, economic, and social atmosphere of the study area. Solid waste management options considered include the collection and transportation of waste, collection of recyclables with single and mixed material bank container systems (SMBCS, MMBCS), material recovery facilities (MRF), composting, biogasification and landfilling. A life cycle inventory (LCI) of the six scenarios along with the baseline scenario was completed; this helped to quantify the CO2 equivalents, emitted and avoided, for energy consumption, production, fuel consumption, and methane (CH4) emissions. LCI results showed that the contribution of the baseline scenario to the global warming potential as CO2 equivalents was a maximum of 838,116 tons. The sixth scenario had a maximum reduction of GHG emissions in terms of CO2 equivalents of -33,773 tons, but the most workable scenario for the current situation in the study area is scenario 5. It saves 25% in CO2 equivalents compared to the baseline scenario.

  6. The impact of municipal solid waste treatment methods on greenhouse gas emissions in Lahore, Pakistan

    International Nuclear Information System (INIS)

    Batool, Syeda Adila; Chuadhry, Muhammad Nawaz

    2009-01-01

    The contribution of existing municipal solid waste management to emission of greenhouse gases and the alternative scenarios to reduce emissions were analyzed for Data Ganj Bukhsh Town (DGBT) in Lahore, Pakistan using the life cycle assessment methodology. DGBT has a population of 1,624,169 people living in 232,024 dwellings. Total waste generated is 500,000 tons per year with an average per capita rate of 0.84 kg per day. Alternative scenarios were developed and evaluated according to the environmental, economic, and social atmosphere of the study area. Solid waste management options considered include the collection and transportation of waste, collection of recyclables with single and mixed material bank container systems (SMBCS, MMBCS), material recovery facilities (MRF), composting, biogasification and landfilling. A life cycle inventory (LCI) of the six scenarios along with the baseline scenario was completed; this helped to quantify the CO 2 equivalents, emitted and avoided, for energy consumption, production, fuel consumption, and methane (CH 4 ) emissions. LCI results showed that the contribution of the baseline scenario to the global warming potential as CO 2 equivalents was a maximum of 838,116 tons. The sixth scenario had a maximum reduction of GHG emissions in terms of CO 2 equivalents of -33,773 tons, but the most workable scenario for the current situation in the study area is scenario 5. It saves 25% in CO 2 equivalents compared to the baseline scenario

  7. Solid-phase characterization in flammable-gas-tank sludges by electron microscopy

    International Nuclear Information System (INIS)

    Liu, J.; Pederson, L.R.; Qang, L.Q.

    1995-09-01

    The crystallinity, morphology, chemical composition, and crystalline phases of several Tank 241-SY-101 (hereinafter referred to as SY-101) and Tank 241-SY-103 (hereinafter referred to as SY-103) solid samples were studied by transmission electron microscopy (TEM), electron energy dispersive spectroscopy (EDS), and electron diffraction. The main focus is on the identification of aluminum hydroxide thought to be present in these tank samples. Aluminum hydroxide was found in SY-103, but not in SY-101. This difference can be explained by the different OH/Al ratios found in the two tank samples: a high OH/Al ratio in SY-101 favors the formation of sodium aluminate, but a low OH/Al ratio in SY-103 favors aluminum hydroxide. These results were confirmed by a magnetic resonance study on SY-101 and SY-103 simulant. The transition from aluminum hydroxide to sodium aluminate occurs at an OH/Al molar ratio of 3.6. It is believed that the study of Al(OH) 3 was not affected by sample preparation because all Al(OH) 3 is in the solid form according to the NMR experiments. There is no Al(OH) 3 in the liquid. It is, therefore, most likely that the observation of Al(OH) 3 is representative of the real sludge sample, and is not affected by drying. Similar conclusions also apply to other insoluble phases such as iron and chromium

  8. Kinetics of solid-gas reactions characterized by scanning AC nano-calorimetry with application to Zr oxidation

    International Nuclear Information System (INIS)

    Xiao, Kechao; Lee, Dongwoo; Vlassak, Joost J.

    2014-01-01

    Scanning AC nano-calorimetry is a recently developed experimental technique capable of measuring the heat capacity of thin-film samples of a material over a wide range of temperatures and heating rates. Here, we describe how this technique can be used to study solid-gas phase reactions by measuring the change in heat capacity of a sample during reaction. We apply this approach to evaluate the oxidation kinetics of thin-film samples of zirconium in air. The results confirm parabolic oxidation kinetics with an activation energy of 0.59 ± 0.03 eV. The nano-calorimetry measurements were performed using a device that contains an array of micromachined nano-calorimeter sensors in an architecture designed for combinatorial studies. We demonstrate that the oxidation kinetics can be quantified using a single sample, thus enabling high-throughput mapping of the composition-dependence of the reaction rate.

  9. Solid phase microextraction capillary gas chromatography combined with furnace atomization plasma emission spectrometry for speciation of mercury in fish tissues

    International Nuclear Information System (INIS)

    Grinberg, Patricia; Campos, Reinaldo C.; Mester, Zoltan; Sturgeon, Ralph E.

    2003-01-01

    The use of solid phase microextraction in conjunction with tandem gas chromatography-furnace atomization plasma emission spectrometry (SPME-GC-FAPES) was evaluated for the determination of methylmercury and inorganic mercury in fish tissue. Samples were digested with methanolic potassium hydroxide, derivatized with sodium tetraethylborate and extracted by SPME. After the SPME extraction, species were separated by GC and detected by FAPES. All experimental parameters were optimized for best separation and analytical response. A repeatability precision of typically 2% can be achieved with long-term (3 months) reproducibility precision of 4.3%. Certified Reference Materials DORM-2, DOLT-2 and TORT-2 from the National Research Council of Canada were analyzed to verify the accuracy of this technique. Detection limits of 1.5 ng g -1 for methylmercury and 0.7 ng g -1 for inorganic mercury in biological tissues were obtained

  10. Evaluation of solid-phase microextraction conditions for the determination of polycyclic aromatic hydrocarbons in aquatic species using gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Aguinaga, N.; Campillo, N.; Vinas, P.; Hernandez-Cordoba, M. [University of Murcia, Department of Analytical Chemistry, Faculty of Chemistry, Murcia (Spain)

    2008-06-15

    This paper describes a headspace solid-phase microextraction (HS-SPME) procedure coupled to gas chromatography with mass spectrometric detection (GC-MS) for the determination of eight PAHs in aquatic species. The influence of various parameters on the PAH extraction efficiency was carefully examined. At 75 C and for an extraction time of 60 min, a polydimethylsiloxane-divinylbenzene (PDMS/DVB) fiber coating was found to be most suitable. Under the optimized conditions, detection limits ranged from 8 to 450 pg g{sup -1}, depending on the compound and the sample matrix. The repeatability varied between 7 and 15% (RSD). Accuracy was tested using the NIST SRM 1974b reference material. The method was successfully applied to different samples, and the studied PAHs were detected in several of the samples. (orig.)

  11. The leaf volatile constituents of Isatis tinctoria by Solid-Phase Microextraction and Gas chromatography/Mass Spectrometry.

    Science.gov (United States)

    Condurso, Cettina; Verzera, Antonella; Romeo, Vincenza; Ziino, Marisa; Trozzi, Alessandra; Ragusa, Salvatore

    2006-08-01

    The leaf volatile constituents of Isatis tinctoria L. (Brassicaceae) have been studied by Solid-Phase Microextraction and Gas chromatography/Mass Spectrometry (SPME/GC-MS). Seventy components were fully characterized by mass spectra, linear retention indices, and injection of standards; the average composition (ppm) as single components and classes of substances is reported. Aliphatic hydrocarbons, acids, alcohols, aldehydes and esters, aromatic aldehydes, esters and ethers, furans, isothiocyanates and thiocyanates, sulfurated compounds, nitriles, terpenes and sesquiterpenes were identified. Leaf volatiles in Isatis tinctoria L. were characterized by a high amount of isothiocyanates which accounted for about 40 % of the total volatile fraction. Isothiocyanates are important and characteristic flavour compounds in Brassica vegetables and the cancer chemo-protective attributes are recently responsible for their growing interest.

  12. Comparison of eye-safe solid state laser DIAL with passive gas filter correlation measurements from aircraft and spacecraft

    Science.gov (United States)

    Hess, Robert V.; Staton, Leo D.; Wallio, H. Andrew; Wang, Liang-Guo

    1992-01-01

    Differential Absorption Lidar (DIAL) using solid state Ti:sapphire lasers finds current application in the NASA/LASE Project for H2O vapor measurements in the approximately = 0.820 micron region for the lower and mid-troposphere and in potential future applications in planned measurements of the approximately = 0.940 micron region where both strong and weak absorption lines enables measurements throughout the troposphere and lower stratosphere. The challenge exists to perform measurements in the eye-safe greater than 1.5 micron region. A comparison between DIAL and passive Gas Filter Correlation Radiometer (GFCR) measurements is made. The essence of the differences in signal to noise ratio for DIAL and passive GFCR measurements is examined. The state of the art of lasers and optical parametric oscillators (OPO's) is discussed.

  13. Determination of some volatile compounds in alcoholic beverage by headspace solid-phase microextraction gas chromatography - mass spectrometry

    Science.gov (United States)

    Schmutzer, G.; Avram, V.; Feher, I.; David, L.; Moldovan, Z.

    2012-02-01

    The volatile composition of alcoholic beverage was studied by headspace solid-phase microextraction (HSSPME) method and gas chromatography - mass spectrometry (GC-MS). Some volatile compounds, such as alcohols, esters, terpenes and other are mainly responsible for the flavor of fortified wines and their amounts specify the quality of the alcoholic beverages. From this perspective it is interesting to develop a rapid, selective and sensitive analytical method suitable for simultaneous quantification of the main molecules being responsible for the organoleptic characteristic of alcoholic beverages. Vermouth fortified drink was analyzed in order to characterize the volatile profile. Using the HS-SPME/GC-MS a number of twenty-six volatile compounds from a commercial market alcoholic beverage were identified. The most abundant compounds were m-thymol, o-thymol and eugenol, alongside of the ethyl ester compounds.

  14. Influence of the solid-gas interface on the effective thermal parameters of a two-layer structure in photoacoustic experiments

    International Nuclear Information System (INIS)

    Aguirre, N Munoz; Perez, L MartInez; Garibay-Febles, V; Lozada-Cassou, M

    2004-01-01

    From the theoretical point of view, the influence of the solid-gas interface on the effective thermal parameters in a two-layer structure of the photoacoustic technique is discussed. It is shown that the effective thermal parameters depend strongly upon the thermal resistance value associated with the solid-gas interface. New expressions for the effective thermal conductivity and thermal diffusivity in the low frequency limit are obtained. In the high frequency limit, the 'resonant' behaviour of the effective thermal diffusivity is maintained and a new complex dependence on frequency of the effective thermal conductivity is shown

  15. Determination of amphetamine-type stimulants in oral fluid by solid-phase microextraction and gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Daniele Z., E-mail: daniele.dzs@dpf.gov.br [Setor Tecnico-Cientifico, Superintendencia Regional do Departamento de Policia Federal no Rio Grande do Sul, 1365 Ipiranga Avenue, Azenha, Zip Code 90160-093 Porto Alegre, Rio Grande do Sul (Brazil); Programa de Pos-Graduacao em Ciencias Farmaceuticas, Faculdade de Farmacia, Universidade Federal do Rio Grande do Sul, 2752 Ipiranga Avenue, Santana, Zip Code 90610-000 Porto Alegre, Rio Grande do Sul (Brazil); Boehl, Paula O.; Comiran, Eloisa; Mariotti, Kristiane C. [Programa de Pos-Graduacao em Ciencias Farmaceuticas, Faculdade de Farmacia, Universidade Federal do Rio Grande do Sul, 2752 Ipiranga Avenue, Santana, Zip Code 90610-000 Porto Alegre, Rio Grande do Sul (Brazil); Pechansky, Flavio [Centro de Pesquisa em Alcool e Drogas (CPAD), Hospital de Clinicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, 2350, Ramiro Barcelos Street, Zip Code 90035-903 Porto Alegre, Rio Grande do Sul (Brazil); Duarte, Paulina C.A.V. [Secretaria Nacional de Politicas sobre Drogas (SENAD), Esplanada dos Ministerios, Block ' A' , 5th floor, Zip Code 70050-907 Brasilia, Distrito Federal (Brazil); De Boni, Raquel [Centro de Pesquisa em Alcool e Drogas (CPAD), Hospital de Clinicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, 2350, Ramiro Barcelos Street, Zip Code 90035-903 Porto Alegre, Rio Grande do Sul (Brazil); Froehlich, Pedro E.; Limberger, Renata P. [Programa de Pos-Graduacao em Ciencias Farmaceuticas, Faculdade de Farmacia, Universidade Federal do Rio Grande do Sul, 2752 Ipiranga Avenue, Santana, Zip Code 90610-000 Porto Alegre, Rio Grande do Sul (Brazil)

    2011-06-24

    Graphical abstract: Highlights: > Propylchloroformate derivatization of amphetamine-type stimulants in oral fluid. > Direct immersion solid-phase microextraction/gas chromatography-mass spectrometry. > Linear range 2(4)-256 ng mL{sup -1}, detection limits 0.5-2 ng mL{sup -1}. > Accuracy 98-112%, precision <15% of RSD, recovery 77-112%. > Importance of residual evaluation in checking model goodness-of-fit. - Abstract: A method for the simultaneous identification and quantification of amphetamine (AMP), methamphetamine (MET), fenproporex (FEN), diethylpropion (DIE) and methylphenidate (MPH) in oral fluid collected with Quantisal{sup TM} device has been developed and validated. Thereunto, in-matrix propylchloroformate derivatization followed by direct immersion solid-phase microextraction and gas chromatography-mass spectrometry were employed. Deuterium labeled AMP was used as internal standard for all the stimulants and analysis was performed using the selected ion monitoring mode. The detector response was linear for the studied drugs in the concentration range of 2-256 ng mL{sup -1} (neat oral fluid), except for FEN, whereas the linear range was 4-256 ng mL{sup -1}. The detection limits were 0.5 ng mL{sup -1} (MET), 1 ng mL{sup -1} (MPH) and 2 ng mL{sup -1} (DIE, AMP, FEN), respectively. Accuracy of quality control samples remained within 98.2-111.9% of the target concentrations, while precision has not exceeded 15% of the relative standard deviation. Recoveries with Quantisal{sup TM} device ranged from 77.2% to 112.1%. Also, the goodness-of-fit concerning the ordinary least squares model in the statistical inference of data has been tested through residual plotting and ANOVA. The validated method can be easily automated and then used for screening and confirmation of amphetamine-type stimulants in drivers' oral fluid.

  16. Determination of amphetamine-type stimulants in oral fluid by solid-phase microextraction and gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    Souza, Daniele Z.; Boehl, Paula O.; Comiran, Eloisa; Mariotti, Kristiane C.; Pechansky, Flavio; Duarte, Paulina C.A.V.; De Boni, Raquel; Froehlich, Pedro E.; Limberger, Renata P.

    2011-01-01

    Graphical abstract: Highlights: → Propylchloroformate derivatization of amphetamine-type stimulants in oral fluid. → Direct immersion solid-phase microextraction/gas chromatography-mass spectrometry. → Linear range 2(4)-256 ng mL -1 , detection limits 0.5-2 ng mL -1 . → Accuracy 98-112%, precision TM device has been developed and validated. Thereunto, in-matrix propylchloroformate derivatization followed by direct immersion solid-phase microextraction and gas chromatography-mass spectrometry were employed. Deuterium labeled AMP was used as internal standard for all the stimulants and analysis was performed using the selected ion monitoring mode. The detector response was linear for the studied drugs in the concentration range of 2-256 ng mL -1 (neat oral fluid), except for FEN, whereas the linear range was 4-256 ng mL -1 . The detection limits were 0.5 ng mL -1 (MET), 1 ng mL -1 (MPH) and 2 ng mL -1 (DIE, AMP, FEN), respectively. Accuracy of quality control samples remained within 98.2-111.9% of the target concentrations, while precision has not exceeded 15% of the relative standard deviation. Recoveries with Quantisal TM device ranged from 77.2% to 112.1%. Also, the goodness-of-fit concerning the ordinary least squares model in the statistical inference of data has been tested through residual plotting and ANOVA. The validated method can be easily automated and then used for screening and confirmation of amphetamine-type stimulants in drivers' oral fluid.

  17. Stability analysis of unsaturated soil slope during rainfall infiltration using coupled liquid-gas-solid three-phase model

    Directory of Open Access Journals (Sweden)

    Dong-mei Sun

    2016-07-01

    Full Text Available Generally, most soil slope failures are induced by rainfall infiltration, a process that involves interactions between the liquid phase, gas phase, and solid skeleton in an unsaturated soil slope. In this study, a loosely coupled liquid-gas-solid three-phase model, linking two numerical codes, TOUGH2/EOS3, which is used for water-air two-phase flow analysis, and FLAC3D, which is used for mechanical analysis, was established. The model was validated through a documented water drainage experiment over a sandy column and a comparison of the results with measured data and simulated results from other researchers. The proposed model was used to investigate the features of water-air two-phase flow and stress fields in an unsaturated soil slope during rainfall infiltration. The slope stability analysis was then performed based on the simulated water-air two-phase seepage and stress fields on a given slip surface. The results show that the safety factor for the given slip surface decreases first, then increases, and later decreases until the rainfall stops. Subsequently, a sudden rise occurs. After that, the safety factor decreases continually and reaches its lowest value, and then increases slowly to a steady value. The lowest value does not occur when the rainfall stops, indicating a delayed effect of the safety factor. The variations of the safety factor for the given slip surface are therefore caused by a combination of pore-air pressure, matric suction, normal stress, and net normal stress.

  18. Numerical Simulation and Experimental Study on the Gas-Solid Coupling of the Aerostatic Thrust Bearing with Elastic Equalizing Pressure Groove

    Directory of Open Access Journals (Sweden)

    Zhao Xiao-long

    2017-01-01

    Full Text Available Aiming at the problem of low stiffness of aerostatic bearing, according to the principle of gas-solid coupling, this paper designs a kind of aerostatic thrust bearing with elastic equalizing pressure groove (EEPG and investigates the effect of elastic equalizing pressure groove (EEPG on the stiffness of aerostatic bearing. According to the physical model of the bearing, one deduces the deformation control equation of the elastic equalizing pressure groove and the control equation of gas lubrication, using finite difference method to derive the control equations and coupling calculation. The bearing capacity and stiffness of aerostatic bearing with EEPG in different gas film clearance are obtained. The calculation results show that the stiffness increased by 59%. The results of numerical calculation and experimental results have good consistency, proving the gas-solid coupling method can improve the bearing stiffness.

  19. Carbonate formation in non-aqueous environments by solid-gas carbonation of silicates

    Science.gov (United States)

    Day, S. J.; Thompson, S. P.; Evans, A.; Parker, J. E.

    2012-02-01

    We have produced synthetic analogues of cosmic silicates using the Sol Gel method, producing amorphous silicates of composition Mg(x)Ca(1-x)SiO3. Using synchrotron X-ray powder diffraction on Beamline I11 at the Diamond Light Source, together with a newly-commissioned gas cell, real-time powder diffraction scans have been taken of a range of silicates exposed to CO2 under non-ambient conditions. The SXPD is complemented by other techniques including Raman and Infrared Spectroscopy and SEM imaging.

  20. Exergy Analysis of an Intermediate Temperature Solid Oxide Fuel Cell-Gas Turbine Hybrid System Fed with Ethanol

    Directory of Open Access Journals (Sweden)

    Fotini Tzorbatzoglou

    2012-10-01

    Full Text Available In the present work, an ethanol fed Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT system has been parametrically analyzed in terms of exergy and compared with a single SOFC system. The solid oxide fuel cell was fed with hydrogen produced from ethanol steam reforming. The hydrogen utilization factor values were kept between 0.7 and 1. The SOFC’s Current-Volt performance was considered in the range of 0.1–3 A/cm2 at 0.9–0.3 V, respectively, and at the intermediate operating temperatures of 550 and 600 °C, respectively. The curves used represent experimental results obtained from the available bibliography. Results indicated that for low current density values the single SOFC system prevails over the SOFC-GT hybrid system in terms of exergy efficiency, while at higher current density values the latter is more efficient. It was found that as the value of the utilization factor increases the SOFC system becomes more efficient than the SOFC-GT system over a wider range of current density values. It was also revealed that at high current density values the increase of SOFC operation temperature leads in both cases to higher system efficiency values.

  1. A variational approach to multi-phase motion of gas, liquid and solid based on the level set method

    Science.gov (United States)

    Yokoi, Kensuke

    2009-07-01

    We propose a simple and robust numerical algorithm to deal with multi-phase motion of gas, liquid and solid based on the level set method [S. Osher, J.A. Sethian, Front propagating with curvature-dependent speed: Algorithms based on Hamilton-Jacobi formulation, J. Comput. Phys. 79 (1988) 12; M. Sussman, P. Smereka, S. Osher, A level set approach for capturing solution to incompressible two-phase flow, J. Comput. Phys. 114 (1994) 146; J.A. Sethian, Level Set Methods and Fast Marching Methods, Cambridge University Press, 1999; S. Osher, R. Fedkiw, Level Set Methods and Dynamics Implicit Surface, Applied Mathematical Sciences, vol. 153, Springer, 2003]. In Eulerian framework, to simulate interaction between a moving solid object and an interfacial flow, we need to define at least two functions (level set functions) to distinguish three materials. In such simulations, in general two functions overlap and/or disagree due to numerical errors such as numerical diffusion. In this paper, we resolved the problem using the idea of the active contour model [M. Kass, A. Witkin, D. Terzopoulos, Snakes: active contour models, International Journal of Computer Vision 1 (1988) 321; V. Caselles, R. Kimmel, G. Sapiro, Geodesic active contours, International Journal of Computer Vision 22 (1997) 61; G. Sapiro, Geometric Partial Differential Equations and Image Analysis, Cambridge University Press, 2001; R. Kimmel, Numerical Geometry of Images: Theory, Algorithms, and Applications, Springer-Verlag, 2003] introduced in the field of image processing.

  2. [Determination of short chain chlorinated paraffins in leather products by solid phase extraction coupled with gas chromatography-mass spectrometry].

    Science.gov (United States)

    Zhang, Weiya; Wan, Xin; Li, Lixia; Wang, Chengyun; Jin, Shupei; Xing, Jun

    2014-10-01

    The short chain chlorinated paraffins (SCCPs) are the additives frequently used in the leather production in China, but they have been put into the list of forbidden chemicals issued by European Union recently. In fact, there is not a commonly recognized method for the determination of the SCCPs in the leather products due to the serious matrix interferences from the leather products and the complex chemical structures of the SCCPs. A method of solid phase extraction coupled with gas chromatography-mass spectrometry (SPE-GC-MS) was established for the determination of the SCCPs in the leather products after the optimization of the SPE conditions. It was found that the interferences from the leather products were thor- oughly separated from the analyte of the SCCPs on a home-made solid phase extraction (SPE) column filled with silica packing while eluted with a mixed solvent of n-hexane-methylene chloride (2:1, v/v). With this method, the recoveries for the SCCPs spiked in the real leather samples varied from 90.47% to 99.00% with the relative standard deviations (RSDs) less than 6.7%, and the limits of detection (LODs) were between 0.069 and 0.110 mg/kg. This method is suitable for qualitative and quantitative analysis of SCCPs in the leather products.

  3. Transport of temperature-velocity covariance in gas-solid flow and its relation to the axial dispersion coefficient

    Science.gov (United States)

    Subramaniam, Shankar; Sun, Bo

    2015-11-01

    The presence of solid particles in a steady laminar flow generates velocity fluctuations with respect to the mean fluid velocity that are termed pseudo-turbulence. The level of these pseudo-turbulent velocity fluctuations has been characterized in statistically homogeneous fixed particle assemblies and freely evolving suspensions using particle-resolved direct numerical simulation (PR-DNS) by Mehrabadi et al. (JFM, 2015), and it is found to be a significant contribution to the total kinetic energy associated with the flow. The correlation of these velocity fluctuations with temperature (or a passive scalar) generates a flux term that appears in the transport equation for the average fluid temperature (or average scalar concentration). The magnitude of this transport of temperature-velocity covariance is quantified using PR-DNS of thermally fully developed flow past a statistically homogeneous fixed assembly of particles, and the budget of the average fluid temperature equation is presented. The relation of this transport term to the axial dispersion coefficient (Brenner, Phil. Trans. Roy. Soc. A, 1980) is established. The simulation results are then interpreted in the context of our understanding of axial dispersion in gas-solid flow. NSF CBET 1336941.

  4. Determination of chlorinated polycyclic aromatic hydrocarbons in water by solid-phase extraction coupled with gas chromatography and mass spectrometry.

    Science.gov (United States)

    Wang, Xianli; Kang, Haiyan; Wu, Junfeng

    2016-05-01

    Given the potential risks of chlorinated polycyclic aromatic hydrocarbons, the analysis of their presence in water is very urgent. We have developed a novel procedure for determining chlorinated polycyclic aromatic hydrocarbons in water based on solid-phase extraction coupled with gas chromatography and mass spectrometry. The extraction parameters of solid-phase extraction were optimized in detail. Under the optimal conditions, the proposed method showed wide linear ranges (1.0-1000 ng/L) with correlation coefficients ranging from 0.9952 to 0.9998. The limits of detection and the limits of quantification were in the range of 0.015-0.591 and 0.045-1.502 ng/L, respectively. Recoveries ranged from 82.5 to 102.6% with relative standard deviations below 9.2%. The obtained method was applied successfully to the determination of chlorinated polycyclic aromatic hydrocarbons in real water samples. Most of the chlorinated polycyclic aromatic hydrocarbons were detected and 1-monochloropyrene was predominant in the studied water samples. This is the first report of chlorinated polycyclic aromatic hydrocarbons in water samples in China. The toxic equivalency quotients of chlorinated polycyclic aromatic hydrocarbons in the studied tap water were 9.95 ng the toxic equivalency quotient m(-3) . 9,10-Dichloroanthracene and 1-monochloropyrene accounted for the majority of the total toxic equivalency quotients of chlorinated polycyclic aromatic hydrocarbons in tap water. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Baseline options and greenhouse gas emission reduction of clean development mechanism project in urban solid waste management

    Energy Technology Data Exchange (ETDEWEB)

    Hiramatsu, Ai; Hanaki, K. [Department of Urban Engineering, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Aramaki, T. [Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904(Japan)

    2003-07-01

    The Clean Development Mechanism (CDM) was adopted in the Kyoto Protocol as a flexibility mechanism to reduce greenhouse gases (GHGs) and has been started with such projects as improving efficiency of individual technology. Although applying various countermeasures to urban areas has significant potentials for reducing GHGs, these countermeasures have not been proposed as CDM projects in the practical stage. A CDM project needs to be validated that it will reduce GHGs additionally compared with a baseline, that is, a predictive value of GHG emissions in the absence of the project. This study examined the introduction of solid waste incineration with electricity generation into three different cities, A, B and C. The main solid waste treatment and the main fuel source are landfill and coal, respectively, in City A, incineration and natural gas in City B, and landfill and hydro in City C. GHG emission reductions of each city under several baseline options assumed here were evaluated. Even if the same technology is introduced, the emission reduction greatly varies according to the current condition and the future plan of the city: 1043-1406 kg CO2/t of waste in City A, 198-580 kg CO2/t in City B, and wide range of zero to over 1000 kg CO2/t in City C. Baseline options also cause significant difference in the emission reduction even in the same city (City C). Incinerating solid waste after removing plastics by source separation in City B increased GHG emission reduction potential up to 730-900 kg CO2/t, which enhances the effectiveness as a CDM project.

  6. Tank designs for combined high pressure gas and solid state hydrogen storage

    DEFF Research Database (Denmark)

    Mazzucco, Andrea

    Many challenges have still to be overcome in order to establish a solid ground for significant market penetration of fuel cell hydrogen vehicles. The development of an effective solution for on-board hydrogen storage is one of the main technical tasks that need to be tackled. The present thesis...... deals with the development of a simulation tool to design and compare different vehicular storage options with respect to targets based upon storage and fueling efficiencies. The set targets represent performance improvements with regard to the state-of-the-art technology and are separately defined...... volume. Heat transfer augmentation techniques (e.g. encapsulation) are found to be the reward strategy to achieve the same stored mass and fueling time of the standard technology, while enabling ambient temperature fueling and save the energy cooling demand (4.2 MJ per fueling) at the refueling station....

  7. Carbon-14 immobilization via the CO2-Ba(OH)2 hydrate gas-solid reaction

    International Nuclear Information System (INIS)

    Haag, G.L.

    1981-08-01

    For the treatment of an air-based off-gas stream, the use of packed beds of Ba(OH) 2 .8H 2 O flakes to remove CO 2 has been demonstrated. However, the operating conditions must be maintained between certain upper and lower limits with respect to the partial pressure of water. If the water vapor pressure in the gas is less than the dissociation vapor pressure of Ba(OH) 2 .8H 2 O, the bed will deactivate. If the vapor pressure is considerably greater, pressure drop problems will increase with increaseing humidity as the particles curl and degrade. Results have indicted that when operated in the proper regime, the bulk of the increase in pressure drop results from the conversion of Ba(OH) 2 .8H 2 O to BaCO 3 and not from the hydration of the commercial Ba(OH) 2 .8H 2 O (i.e., Ba(OH) 2 .7.50H 2 O) to Ba(OH) 2 .8H 2 O

  8. Necessary conditions for the homogeneous formation of a volume avalanche discharge with specific applications to rare gas-halide excimer laser discharges

    International Nuclear Information System (INIS)

    Levatter, J.I.

    1979-01-01

    Self-sustained/avalanche discharges are an efficient method of rare gas-halide excimer laser excitation in small systems. However, with the exceptions of the work reported here, experiments attempting to increase the laser energy output by scaling up the discharge volume and/or pulse duration have not been successful. The major problem encountered in scaling experiments has been the formation of arc channels in the discharge volume. The presence of arcing can totally disrupt proper laser operation. This problem stems from a general lack of understanding of high pressure avalanche discharge phenomena. Therefore, clarifying the basic discharge formation process and establishing a set of criteria under which a homogeneous avalanche discharge can be obtained is of central importance in defining the scaling limits of avalanche discharge lasers. The work presented here reviews the phenomena involved in high E/n (electric field to gas number density ratio) breakdown and its relationship to the formation of spatially homogeneous discharges. This relationship was first explored by A.J. Palmer in 1974. The basic requirement of his model was that the preionization density be large enough to cause an appreciable overlap of the primary electron avalanches and hence smooth out the ensuing space-charge fields to the extent that individual streamer formation would be prevented. This is the same basic model used in the more detailed discharge formation analysis developed here except that the effects of a time varying electric field caused by a finite voltage rise time and the effects due to the various electrochemical properties of the gas mixture are property taken into consideration

  9. Analyzer for measurement of nitrogen oxide concentration by ozone content reduction in gas using solid state chemiluminescent sensor

    Science.gov (United States)

    Chelibanov, V. P.; Ishanin, G. G.; Isaev, L. N.

    2014-05-01

    Role of nitrogen oxide in ambient air is described and analyzed. New method of nitrogen oxide concentration measurement in gas phase is suggested based on ozone concentration measurement with titration by nitrogen oxide. Research of chemiluminescent sensor composition is carried out on experimental stand. The sensor produced on the base of solid state non-activated chemiluminescent composition is applied as ozone sensor. Composition is put on the surface of polymer matrix with developed surface. Sensor compositions includes gallic acid with addition of rodamine-6G. Model of interaction process between sensor composition and ozone has been developed, main products appeared during reaction are identified. The product determining the speed of luminescense appearance is found. This product belongs to quinone class. Then new structure of chemiluminescent composition was suggested, with absence of activation period and with high stability of operation. Experimental model of gas analyzer was constructed and operation algorithm was developed. It was demonstrated that developed NO measuring instrument would be applied for monitoring purposes of ambient air. This work was partially financially supported by Government of Russian Federation, Grant 074-U01

  10. Gas-Induced Rectified Motion of a Solid Object in a Liquid-Filled Housing during Vibration: Analysis and Experiments

    Science.gov (United States)

    Torczynski, J. R.; O'Hern, T. J.; Clausen, J. R.; Koehler, T. P.

    2017-11-01

    The motion of a solid object (a piston) that fits closely within a housing filled with viscous liquid is studied. If a small amount of gas is introduced and the system is subjected to axial vibration, then the piston exhibits rectified motion when the drag on the piston depends on its position within the housing. An idealized system, in which the piston is suspended freely between two springs and the gas is replaced with two compressible bellows, is analyzed theoretically and studied experimentally. For a given vibration amplitude or frequency, the piston either remains near its original position (``up'') or moves to a different position (``down''), where its spring suspension is compressed. Analytical and experimental regime maps of the amplitudes and frequencies at which the piston is up or down are in good agreement. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.

  11. Greenhouse gas footprint and the carbon flow associated with different solid waste management strategy for urban metabolism in Bangladesh.

    Science.gov (United States)

    Islam, K M Nazmul

    2017-02-15

    Greenhouse gas (GHG) emissions from municipal solid waste (MSW) and associated climate change consequences are gripping attention globally, while MSW management as a vital subsystem of urban metabolism significantly influences the urban carbon cycles. This study evaluates the GHG emissions and carbon flow of existing and proposed MSW management in Bangladesh through scenario analysis, including landfill with landfill gas (LFG) recovery, waste to energy (WtE), and material recovery facility (MRF). The analysis indicates that, scenario H 2 and H 5 emitted net GHGs -152.20kg CO 2 eq. and -140.32kg CO 2 eq., respectively, in comparison with 420.88kg CO 2 eq. of scenario H 1 for managing per ton of wastes during the reference year 2015. The annual horizontal carbon flux of the waste input was 319Gg and 158Gg during 2015 in Dhaka and Chittagong, respectively. An integrated strategy of managing the wastes in the urban areas of Bangladesh involving WtE incineration plant and LFG recovery to generate electricity as well as MRF could reverse back 209.46Gg carbon and 422.29Gg carbon to the Chittagong and Dhaka urban system, respectively. This study provides valuable insights for the MSW policy framework and revamp of existing MSW management practices with regards to reduction of GHGs emissions from the waste sector in Bangladesh. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Headspace solid-phase microextraction coupled to gas chromatography for the analysis of aldehydes in edible oils.

    Science.gov (United States)

    Ma, Chunhua; Ji, Jiaojiao; Tan, Connieal; Chen, Dongmei; Luo, Feng; Wang, Yiru; Chen, Xi

    2014-03-01

    Oxidation has important effects on the quality of edible oils. In particular, the generation of aldehydes produced by the oxidation of oils is one of the deteriorative factors to their quality. The aim of this study was to develop a method to determine the aldehydes as lipid oxidation markers in edible oils. Seven aldehydes generated from lipid oxidation were studied using headspace solid-phase microextraction coupled to gas chromatography with a flame ionization detector. The extraction efficiency of five commercial fibers was investigated and the influence of extraction temperature, extraction time, desorption temperature, and desorption time were optimized. The best result was obtained with 85 μm carboxen/polydimethylsiloxane, extraction at 50 °C for 15 min and desorption in the gas chromatography injector at 250 °C for 2 min. Under the optimized conditions, the content of hexanal was the highest of the seven aldehydes in all edible oils. The limits of detection for hexanal in the three oils were found to range from 4.6 to 10.2 ng L(-1). The reproducibility of the method was evaluated and the relative standard deviations were less than 8.9%. This developed approach was successfully applied to analyze hexanal in peanut oil, soy oil, and olive oil samples, and these results were compared with those obtained using the thiobarbituric acid-reactive substances (TBARs) method. © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  13. Chloride pyrometallurgy of uranium ore. 1. Chlorination of phosphate ore using solid or gas chlorinating agent and carbon

    International Nuclear Information System (INIS)

    Taki, Tomihiro; Komoto, Shigetoshi; Otomura, Keiichiro; Takenaka, Toshihide; Sato, Nobuaki; Fujino, Takeo.

    1995-01-01

    A thermodynamical and pyrometallurgical study to recover uranium from the phosphate ores was undertaken using the chloride volatilization method. Iron was chlorinated with solid chlorinating agents such as NaCl and CaCl 2 in combination with activated carbon, which will be used for removing this element from the ore, but uranium was not. On the other hand, the chlorination using Cl 2 gas and activated carbon gave a good result at 1,223 K. Not only uranium but also iron, phosphorus, aluminum and silicon were found to form volatile chlorides which vaporized out of the ore, while calcium remained in the ore as non-volatile CaCl 2 . The chlorination condition was studied as functions of temperature, reaction time and carbon content. The volatilization ratio of uranium around 95% was obtained by heating the mixture of the ore and activated carbon (35 wt%) in a mixed gas flow of Cl 2 (200 ml/min) and N 2 (200 ml/min) at 1,223 K for 120 min. (author)

  14. The comparison of fossil carbon fraction and greenhouse gas emissions through an analysis of exhaust gases from urban solid waste incineration facilities.

    Science.gov (United States)

    Kim, Seungjin; Kang, Seongmin; Lee, Jeongwoo; Lee, Seehyung; Kim, Ki-Hyun; Jeon, Eui-Chan

    2016-10-01

    In this study, in order to understand accurate calculation of greenhouse gas emissions of urban solid waste incineration facilities, which are major waste incineration facilities, and problems likely to occur at this time, emissions were calculated by classifying calculation methods into 3 types. For the comparison of calculation methods, the waste characteristics ratio, dry substance content by waste characteristics, carbon content in dry substance, and (12)C content were analyzed; and in particular, CO2 concentration in incineration gases and (12)C content were analyzed together. In this study, 3 types of calculation methods were made through the assay value, and by using each calculation method, emissions of urban solid waste incineration facilities were calculated then compared. As a result of comparison, with Calculation Method A, which used the default value as presented in the IPCC guidelines, greenhouse gas emissions were calculated for the urban solid waste incineration facilities A and B at 244.43 ton CO2/day and 322.09 ton CO2/day, respectively. Hence, it showed a lot of difference from Calculation Methods B and C, which used the assay value of this study. It is determined that this was because the default value as presented in IPCC, as the world average value, could not reflect the characteristics of urban solid waste incineration facilities. Calculation Method B indicated 163.31 ton CO2/day and 230.34 ton CO2/day respectively for the urban solid waste incineration facilities A and B; also, Calculation Method C indicated 151.79 ton CO2/day and 218.99 ton CO2/day, respectively. This study intends to compare greenhouse gas emissions calculated using (12)C content default value provided by the IPCC (Intergovernmental Panel on Climate Change) with greenhouse gas emissions calculated using (12)C content and waste assay value that can reflect the characteristics of the target urban solid waste incineration facilities. Also, the concentration and (12)C content

  15. Source identification of underground fuel spills by solid-phase microextraction/high-resolution gas chromatography/genetic algorithms.

    Science.gov (United States)

    Lavine, B K; Ritter, J; Moores, A J; Wilson, M; Faruque, A; Mayfield, H T

    2000-01-15

    Solid-phase microextraction (SPME), capillary column gas chromatography, and pattern recognition methods were used to develop a potential method for typing jet fuels so a spill sample in the environment can be traced to its source. The test data consisted of gas chromatograms from 180 neat jet fuel samples representing common aviation turbine fuels found in the United States (JP-4, Jet-A, JP-7, JPTS, JP-5, JP-8). SPME sampling of the fuel's headspace afforded well-resolved reproducible profiles, which were standardized using special peak-matching software. The peak-matching procedure yielded 84 standardized retention time windows, though not all peaks were present in all gas chromatograms. A genetic algorithm (GA) was employed to identify features (in the standardized chromatograms of the neat jet fuels) suitable for pattern recognition analysis. The GA selected peaks, whose two largest principal components showed clustering of the chromatograms on the basis of fuel type. The principal component analysis routine in the fitness function of the GA acted as an information filter, significantly reducing the size of the search space, since it restricted the search to feature subsets whose variance is primarily about differences between the various fuel types in the training set. In addition, the GA focused on those classes and/or samples that were difficult to classify as it trained using a form of boosting. Samples that consistently classify correctly were not as heavily weighted as samples that were difficult to classify. Over time, the GA learned its optimal parameters in a manner similar to a perceptron. The pattern recognition GA integrated aspects of strong and weak learning to yield a "smart" one-pass procedure for feature selection.

  16. Hydrogen Fueled Hybrid Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) System for Long-Haul Rail Application

    Science.gov (United States)

    Chow, Justin Jeff

    Freight movement of goods is the artery for America's economic health. Long-haul rail is the premier mode of transport on a ton-mile basis. Concerns regarding greenhouse gas and criteria pollutant emissions, however, have motivated the creation of annually increasing locomotive emissions standards. Health issues from diesel particulate matter, especially near rail yards, have also been on the rise. These factors and the potential to raise conventional diesel-electric locomotive performance warrants the investigation of using future fuels in a more efficient system for locomotive application. This research evaluates the dynamic performance of a Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) Hybrid system operating on hydrogen fuel to power a locomotive over a rail path starting from the Port of Los Angeles and ending in the City of Barstow. Physical constraints, representative locomotive operation logic, and basic design are used from a previous feasibility study and simulations are performed in the MATLAB Simulink environment. In-house controls are adapted to and expanded upon. Results indicate high fuel-to-electricity efficiencies of at least 54% compared to a conventional diesel-electric locomotive efficiency of 35%. Incorporation of properly calibrated feedback and feed-forward controls enables substantial load following of difficult transients that result from train kinematics while maintaining turbomachinery operating requirements and suppressing thermal stresses in the fuel cell stack. The power split between the SOFC and gas turbine is deduced to be a deterministic factor in the balance between capital and operational costs. Using hydrogen results in no emissions if renewable and offers a potential of 24.2% fuel energy savings for the rail industry.

  17. Design and optimization of a combined fuel reforming and solid oxide fuel cell system with anode off-gas recycling

    International Nuclear Information System (INIS)

    Lee, Tae Seok; Chung, J.N.; Chen, Yen-Cho

    2011-01-01

    Highlights: → In this work, an analytical, parametric study is performed to evaluate the feasibility and performance of a combined fuel reforming and SOFC system. → Specifically the effects of adding the anode off-gas recycling and recirculation components and the CO 2 absorbent unit are investigated. → The AOG recycle ratio increases with increasing S/C ratio and the addition of AOG recycle eliminates the need for external water consumption. → The key finding is that for the SOFC operating at 900 deg. C with the steam to carbon ratio at 5 and no AOG recirculation, the system efficiency peaks. - Abstract: An energy conversion and management concept for a combined system of a solid oxide fuel cell coupled with a fuel reforming device is developed and analyzed by a thermodynamic and electrochemical model. The model is verified by an experiment and then used to evaluate the overall system performance and to further suggest an optimal design strategy. The unique feature of the system is the inclusion of the anode off-gas recycle that eliminates the need of external water consumption for practical applications. The system performance is evaluated as a function of the steam to carbon ratio, fuel cell temperature, anode off gas recycle ratio and CO 2 adsorption percentage. For most of the operating conditions investigated, the system efficiency starts at around 70% and then monotonically decreases to the average of 50% at the peak power density before dropping down to zero at the limiting current density point. From an engineering application point of view, the proposed combined fuel reforming and SOFC system with a range of efficiency between 50% and 70% is considered very attractive. It is suggested that the optimal system is the one where the SOFC operates around 900 deg. C with S/C ratio higher than 3, maximum CO 2 capture, and minimum AOG recirculation.

  18. Effect of sewage sludge content on gas quality and solid residues produced by cogasification in an updraft gasifier

    Energy Technology Data Exchange (ETDEWEB)

    Seggiani, Maurizia, E-mail: m.seggiani@diccism.unipi.it [Department of Chemical Engineering, Industrial Chemistry and Material Science, University of Pisa, Largo Lucio Lazzarino 1, 56126 Pisa (Italy); Puccini, Monica, E-mail: m.puccini@diccism.unipi.it [Department of Chemical Engineering, Industrial Chemistry and Material Science, University of Pisa, Largo Lucio Lazzarino 1, 56126 Pisa (Italy); Raggio, Giovanni, E-mail: g.raggio@tiscali.it [Italprogetti Engineering SPA, Lungarno Pacinotti, 59/A, 56020 San Romano (Pisa) (Italy); Vitolo, Sandra, E-mail: s.vitolo@diccism.unipi.it [Department of Chemical Engineering, Industrial Chemistry and Material Science, University of Pisa, Largo Lucio Lazzarino 1, 56126 Pisa (Italy)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Cogasification of sewage sludge with wood pellets in updraft gasifier was analysed. Black-Right-Pointing-Pointer The effects of sewage sludge content on the gasification process were examined. Black-Right-Pointing-Pointer Sewage sludge addition up to 30 wt.% reduces moderately the process performance. Black-Right-Pointing-Pointer At high sewage sludge content slagging and clinker formation occurred. Black-Right-Pointing-Pointer Solid residues produced resulted acceptable at landfills for non-hazardous waste. - Abstract: In the present work, the gasification with air of dehydrated sewage sludge (SS) with 20 wt.% moisture mixed with conventional woody biomass was investigated using a pilot fixed-bed updraft gasifier. Attention was focused on the effect of the SS content on the gasification performance and on the environmental impact of the process. The results showed that it is possible to co-gasify SS with wood pellets (WPs) in updraft fixed-bed gasification installations. However, at high content of sewage sludge the gasification process can become instable because of the very high ash content and low ash fusion temperatures of SS. At an equivalent ratio of 0.25, compared with wood pellets gasification, the addition of sewage sludge led to a reduction of gas yield in favor of an increase of condensate production with consequent cold gas efficiency decrease. Low concentrations of dioxins/furans and PAHs were measured in the gas produced by SS gasification, well below the limiting values for the exhaust gaseous emissions. NH{sub 3}, HCl and HF contents were very low because most of these compounds were retained in the wet scrubber systems. On the other hand, high H{sub 2}S levels were measured due to high sulfur content of SS. Heavy metals supplied with the feedstocks were mostly retained in gasification solid residues. The leachability tests performed according to European regulations showed that metals leachability was

  19. Repowering of an Existing Power Plant by Means of Gas Turbine and Solid Oxide Fuel Cell

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    Repowering is a process consisting in a transformation of an old power plant in order to have a greater nameplate capacity or more efficiency, which result in a net increase of power generated. As a consequence of the higher efficiency, the repow ered plant is characterized by higher power output...... and less specific CO2 emissions. Usually, a repowering is performed adding one or more gas turbines to an existing steam cycle which was built decades ago. Thus, traditional repowering results in combine d cycles (CC). High temperature fuel cells (such as SOFC) could also be used as a topping cycle......, reaching global plant efficiency even higher and specific CO2 emissions even lower. Decreasing the operating temperature in a SOFC allows the use of less compl ex materials and construction methods, consequently reducing plant and the electricity cost. A lower working temperature makes it also suitable...

  20. A study of the thermal activation of synthetic zeolites (molecular sieve) for gas-solid chromatography

    International Nuclear Information System (INIS)

    Walker, J.A.J.

    1978-10-01

    The thermal activation of synthetic zeolites from two sources has been investigated with reference to the adsorption chromatography of inorganic gases. It was found that the heats of adsorption for oxygen and carbon monoxide increased with activation temperatures. Limits of detection for oxygen in argon and conversely argon in oxygen were determined as well as the chromatographic stability of the activated zeolite. The practical implications and importance of the results are discussed and the application to the analysis of fast reactor blanket gas is mentioned. An explanation is proposed for the adsorption behaviour of these activated materials, based on an electrostatic mechanism, and this has suggested a reason for the separation characteristics of oxygen and argon on polar zeolites. Further work is identified including the investigation of energy states of the oxygen molecule adsorbed on activated zeolite by means of ultra-violet photoelectron spectroscopy. (author)

  1. A study of the thermal activation of synthetic zeolites (molecular sieve) for gas-solid chromatography

    International Nuclear Information System (INIS)

    Walker, J.A.J.

    1978-10-01

    The thermal activation of synthetic zeolites from two sources has been investigated with reference to the adsorption chromatography of inorganic gases. It was found that the heats of adsorption for oxygen and carbon monoxide increased with activation temperature. Limits of detection for oxygen in argon and conversely argon in oxygen were determined as well as the chromatographic stability of the activated zeolite. The practical implications and importance of the results are discussed and the application to the analysis of fast reactor blanket gas is mentioned. An explanation is proposed for the adsorption behaviour of these activated materials, based on an electrostatic mechanism, and this has suggested a reason for the separation characteristics of oxygen and argon on polar zeolites. Further work is identified including the investigation of energy states of the oxygen molecule adsorbed on activated zeolite by means of ultra-violet photoelectron spectroscopy. (author)

  2. Gas phase analysis of CO interactions with solid surfaces at high temperatures

    International Nuclear Information System (INIS)

    Anghel, Clara; Hoernlund, Erik; Hultquist, Gunnar; Limbaeck, Magnus

    2004-01-01

    An in situ method including mass spectrometry and labeled gases is presented and used to gain information on adsorption of molecules at high temperatures (>300 deg. C). Isotopic exchange rate in H 2 upon exposure to an oxidized zicaloy-2 sample and exchange rate in CO upon exposure to various materials have been measured. From these measurements, molecular dissociation rates in respective system have been calculated. The influence of CO and N 2 on the uptake rate of H 2 in zirconium and oxidized zicaloy-2 is discussed in terms of tendency for adsorption at high temperatures. In the case of oxidized Cr exposed to CO gas with 12 C, 13 C, 16 O and 18 O, the influence of H 2 O is investigated with respect to dissociation of CO molecules. The presented data supports a view of different tendencies for molecular adsorption of H 2 O, CO, N 2 , and H 2 molecules on surfaces at high temperatures

  3. Recycling of Rare Earth Elements

    Science.gov (United States)

    Lorenz, Tom; Bertau, Martin

    2017-01-01

    Any development of an effective process for rare earth (RE) recycling has become more and more challenging, especially in recent years. Since 2011, when commodity prices of REs had met their all-time maximum, prices have dropped rapidly by more than 90 %. An economic process able to offset these fluctuations has to take unconventional methods into account beside well-known strategies like acid/basic leaching or solvent extraction. The solid-state chlorination provides such an unconventional method for mobilizing RE elements from waste streams. Instead of hydrochloric acid this kind of chlorination decomposes NH4Cl thermally to release up to 400 °C hot HCl gas. After cooling the resulting solid metal chlorides may be easily dissolved in pH-adjusted water. Without producing strongly acidic wastes and with NH4Cl as cheap source for hydrogen chloride, solid-state chlorination provides various advantages in terms of costs and disposal. In the course of the SepSELSA project this method was examined, adjusted and optimized for RE recycling from fluorescent lamp scraps as well as Fe14Nd2B magnets. Thereby many surprising influences and trends required various analytic methods to examine the reasons and special mechanisms behind them.

  4. Municipal solid waste management planning considering greenhouse gas emission trading under fuzzy environment.

    Science.gov (United States)

    Zhang, Xiaodong; Huang, Gordon

    2014-03-15

    Waste management activities can release greenhouse gases (GHGs) to the atmosphere, intensifying global climate change. Mitigation of the associated GHG emissions is vital and should be considered within integrated municipal solid waste (MSW) management planning. In this study, a fuzzy possibilistic integer programming (FPIM) model has been developed for waste management facility expansion and waste flow allocation planning with consideration of GHG emission trading in an MSW management system. It can address the interrelationships between MSW management planning and GHG emission control. The scenario of total system GHG emission control is analyzed for reflecting the feature that GHG emission credits may be tradable. An interactive solution algorithm is used to solve the FPIM model based on the uncertainty-averse preferences of decision makers in terms of p-necessity level, which represents the certainty degree of the imprecise objective. The FPIM model has been applied to a hypothetical MSW planning problem, where optimal decision schemes for facility expansion and waste flow allocation have been achieved with consideration of GHG emission control. The results indicate that GHG emission credit trading can decrease total system cost through re-allocation of GHG emission credits within the entire MSW management system. This will be helpful for decision makers to effectively determine the allowable GHG emission permits in practices. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. SF{sub 6} decomposition and layer formation due to excimer laser photoablation of SiO{sub 2} surface at gas-solid system

    Energy Technology Data Exchange (ETDEWEB)

    Sajad, Batool [Physics Department, Amirkabir University, PO Box 15875-4413, Tehran (Iran, Islamic Republic of); Parvin, Parviz [Physics Department, Amirkabir University, PO Box 15875-4413, Tehran (Iran, Islamic Republic of); Bassam, Mohamad Amin [Excimer Laser Lab, Emam Hussain University, PO Box 16575-4347, Tehrann (Iran, Islamic Republic of)

    2004-12-21

    In this work, the effect of an excimer laser has been studied for presenting a method for SF{sub 6} decomposition and simultaneous formation of a SiF{sub 2} layer on amorphous SiO{sub 2}. Though the excimer laser did not establish a gas phase photodissociation, we have shown that UV photoablation leads strongly to molecular decomposition in the SF{sub 6}-SiO{sub 2} system. Moreover, the dependence of the decomposition process on the exposure parameters such as the wavelength and intensity as well as the gas pressure and the focal point distance from the gas-solid interface has been investigated.

  6. Changes in the Spectral Features of Zinc Phthalocyanine Induced by Nitrogen Dioxide Gas in Solution and in Solid Polymer Nanofiber Media.

    Science.gov (United States)

    Zugle, Ruphino; Tetteh, Samuel

    2017-03-01

    The changes in the spectral features of zinc phthalocyanine in the visible domain as a result of its interaction with nitrogen dioxide gas were assessed in this work. This was done both in solution and when the phthalocyanine was incorporated into a solid polystyrene polymer nanofiber matrix. The spectral changes were found to be spontaneous and marked in both cases suggesting a rapid response criterion for the detection of the gas. In particular, the functionalised nano-fabric material could serve as a practical fire alarm system as it rapidly detects the nitrogen dioxide gas generated during burning.

  7. Simultaneous solution algorithms for Eulerian-Eulerian gas-solid flow models: Stability analysis and convergence behaviour of a point and a plane solver

    International Nuclear Information System (INIS)

    Wilde, Juray de; Vierendeels, Jan; Heynderickx, Geraldine J.; Marin, Guy B.

    2005-01-01

    Simultaneous solution algorithms for Eulerian-Eulerian gas-solid flow models are presented and their stability analyzed. The integration algorithms are based on dual-time stepping with fourth-order Runge-Kutta in pseudo-time. The domain is solved point or plane wise. The discretization of the inviscid terms is based on a low-Mach limit of the multi-phase preconditioned advection upstream splitting method (MP-AUSMP). The numerical stability of the simultaneous solution algorithms is analyzed in 2D with the Fourier method. Stability results are compared with the convergence behaviour of 3D riser simulations. The impact of the grid aspect ratio, preconditioning, artificial dissipation, and the treatment of the source terms is investigated. A particular advantage of the simultaneous solution algorithms is that they allow a fully implicit treatment of the source terms which are of crucial importance for the Eulerian-Eulerian gas-solid flow models and their solution. The numerical stability of the optimal simultaneous solution algorithm is analyzed for different solids volume fractions and gas-solid slip velocities. Furthermore, the effect of the grid resolution on the convergence behaviour and the simulation results is investigated. Finally, simulations of the bottom zone of a pilot-scale riser with a side solids inlet are experimentally validated

  8. Quantitative Analysis of Bisphenol A Leached from Household Plastics by Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry (SPME-GC-MS)

    Science.gov (United States)

    Johnson, Bettie Obi; Burke, Fernanda M.; Harrison, Rebecca; Burdette, Samantha

    2012-01-01

    The measurement of trace levels of bisphenol A (BPA) leached out of household plastics using solid-phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS) is reported here. BPA is an endocrine-disrupting compound used in the industrial manufacture of polycarbonate plastic bottles and epoxy resin can liners. This experiment…

  9. Derivatisation/solid-phase microextraction followed by gas chromatography-mass spectrometry for the analysis of phenoxy acid herbicides in aqueous samples

    DEFF Research Database (Denmark)

    Nilsson, Torben; Baglio, Daniela; Galdo-Miguez, Isabel

    1998-01-01

    Different combinations of derivatisation and solid-phase microextraction followed by gas chromatography-mass spectrometry were optimised and evaluated for the analysis of phenoxy acid herbicides in water. The most successful derivatisation approach was aqueous-phase derivatisation with benzyl...

  10. Data correlation in on-line solid-phase extraction-gas chromatography-atomic emission/mass spectrometric detection of unknown microcontaminants

    NARCIS (Netherlands)

    Hankemeier, Th.; Rozenbrand, J.; Abhadur, M.; Vreuls, J.J.; Brinkman, U.A.Th.

    1998-01-01

    A procedure is described for the (non-target) screening of hetero-atom-containing compounds in tap and waste water by correlating data obtained by gas chromatography (GC) using atomic emission (AED) and mass selective (MS) detection. Solid-phase extraction (SPE) was coupled on-line to both GC

  11. Influence of liquid viscosity and surface tension on the gas-liquid mass transfer coefficient for solid foam packings in co-current two-phase flow

    NARCIS (Netherlands)

    Stemmet, C.P.; Bartelds, F.; Schaaf, van der J.; Kuster, B.F.M.; Schouten, J.C.

    2008-01-01

    The gas–liquid mass transfer coefficient and other hydrodynamic parameters such as liquid holdup and frictional pressure drop are presented for gas and liquid moving in co-current upflow and downflow through solid foam packings of 10 and of 40 pores per linear inch (ppi). The effect of increasing

  12. Dynamic modelling and characterisation of a solid oxide fuel cell integrated in a gas turbine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Thorud, Bjoern

    2005-07-01

    This thesis focuses on three main areas within the field of SOFC/GT-technology: 1) Development of a dynamic SOFC/GT model. 2) Model calibration and sensitivity study. 3) Assessment of the dynamic properties of a SOFC/GT power plant. The SOFC/GT model developed in this thesis describes a pressurised tubular Siemens Westinghouse-type SOFC, which is integrated in a gas turbine cycle. The process further includes a plate-fin recuperator for stack air preheating, a prereformer, an anode exhaust gas recycling loop for steam/carbon-ratio control, an afterburner and a shell-tube heat exchanger for air preheating. The fuel cell tube, the recuperator and the shell-tube heat exchanger are spatially distributed models. The SOFC model is further thermally integrated with the prereformer. The compressor and turbine models are based on performance maps as a general representation of the characteristics. In addition, a shaft model which incorporates moment of inertia is included to account for gas turbine transients. The SOFC model is calibrated against experimentally obtained data from a single-cell experiment performed on a Siemens Westinghouse tubular SOFC. The agreement between the model and the experimental results is good. The sensitivity study revealed that the degree of prereforming is of great importance with respect to the axial temperature distribution of the fuel cell. Types of malfunctions are discussed prior to the dynamic behaviour study. The dynamic study of the SOFC/GT process is performed by simulating small and large load changes according to three different strategies; 1) Load change at constant mean fuel cell temperature. 2) Load change at constant turbine inlet temperature. 3) Load change at constant shaft speed. Of these three strategies, the constant mean fuel cell temperature strategy appears to be the most rapid load change method. Furthermore, this strategy implies the lowest degree of thermal cycling, the smoothest fuel cell temperature distribution and

  13. Rare earth germanates

    International Nuclear Information System (INIS)

    Bondar', I.A.; Vinogradova, N.V.; Dem'yanets, L.N.

    1983-01-01

    From the viewpoint of structural chemistry and general regularities controlling formation reactions of compounds and phases in melts, solid and gaseous states, recent achievements in the chemistry of rare earth germanates are generalized. Methods of synthesizing germanates, systems on the base of germanium oxides and rare earths are considered. The data on crystallochemical characteristics are tabulated. Individual compounds of scandium germanate are also characterized. Processes of germanate formation using the data of IR-spectroscopy, X-ray phase analysis are studied. The structure and morphotropic series of rare earth germanates and silicates are determined. Fields of their present and possible future application are considered

  14. Recovery of methane-rich gas from solid-feed anaerobic digestion of ipomoea (Ipomoea carnea).

    Science.gov (United States)

    Sankar Ganesh, P; Sanjeevi, R; Gajalakshmi, S; Ramasamy, E V; Abbasi, S A

    2008-03-01

    Studies are presented on new types of anaerobic digesters in which chopped or dry crushed Ipomoea carnea was fed without any other pretreatment, in an attempt to develop commercially viable means of utilizing the otherwise very harmful plant. Two types of solid-feed anaerobic digesters (SFADs) were studied. The first type had a single vessel in which the bottom 35% portion was separated from the top portion by a perforated PVC disk. The weed was charged from the top and inoculated with anaerobically digested cowdung-water slurry. The fermentation of the weed in the reactor led to the formation of volatile fatty acids (VFAs) plus some biogas. The leachate, rich in the VFAs, was passed through the perforated PVC sheet and collected in the lower portion of the vessel. The other type of reactors had two vessels, the first one was fully charged with the weed and the second received the VFA leachate. With both types were attached upflow anaerobic filters (UAFs) which converted the leachate into combustible biogas consisting of approximately 70% methane. All SFADs developed very consistent performance in terms of biogas yield within 17 weeks of start. The two-compartment reactors yielded significantly more biogas than the single-compartment reactors of corresponding total volume, and the reactors with which anaerobic filters (AF) were attached yielded more biogas than the ones without AF. The best performing units generated 2.41m(3) of biogas per m(3) of digester volume, as compared to 0.1-0.2m(3) of biogas, m(-3)d(-1), obtainable with conventional digesters. This indicates the viability of this technology. The spent weed can be vermicomposted directly to obtain good soil-conditioner cum fertilizer; earthworm Eudrilus eugeniae produced 540mg vermicast per animal every day, achieving near total conversion of feed to vermicast in 20 days. The proposed systems, thus, makes it possible to accomplish total utilization of ipomoea.

  15. Optimal scenario balance of reduction in costs and greenhouse gas emissions for municipal solid waste management

    Institute of Scientific and Technical Information of China (English)

    邓娜; 张强; 陈广武; 齐长青; 崔文谦; 张于峰; 马洪亭

    2015-01-01

    To reduce carbon intensity, an improved management method balancing the reduction in costs and greenhouse gas (GHG) emissions is required for Tianjin’s waste management system. Firstly, six objective functions, namely, cost minimization, GHG minimization, eco-efficiency minimization, cost maximization, GHG maximization and eco-efficiency maximization, are built and subjected to the same constraints with each objective function corresponding to one scenario. Secondly, GHG emissions and costs are derived from the waste flow of each scenario. Thirdly, the range of GHG emissions and costs of other potential scenarios are obtained and plotted through adjusting waste flow with infinitely possible step sizes according to the correlation among the above six scenarios. And the optimal scenario is determined based on this range. The results suggest the following conclusions. 1) The scenarios located on the border between scenario cost minimization and GHG minimization create an optimum curve, and scenario GHG minimization has the smallest eco-efficiency on the curve;2) Simple pursuit of eco-efficiency minimization using fractional programming may be unreasonable; 3) Balancing GHG emissions from incineration and landfills benefits Tianjin’s waste management system as it reduces GHG emissions and costs.

  16. THREE-FIBER OPTICAL PROBE FOR STUDYING FLUIDIZED GAS-SOLID BEDS IN BUBBLING REGIME

    Directory of Open Access Journals (Sweden)

    ERICK REYES-VERA

    2011-01-01

    Full Text Available En este trabajo se muestra el desarrollo de una sonda con tres fi bras ópticas para estudiar el comportamiento de la burbuja en lechos gas-sólido fl uidizados burbujeantes. Su estructura compacta permite minimizar las perturbaciones inducidas al campo del fl ujo, lográndose resultados más exactos frentes a otros tipos de sonda. Los lechos fl uidizados burbujeantes son ampliamente usados en procesos petroquímicos, metalúrgicos y en termoeléctricas. El comportamiento de la burbuja es uno de los parámetros más importantes para la simulación y diseño de reactores termoeléctricos, dado que se relaciona con los saltos de fase, la interacción entre las fases sólida y gaseosa del lecho y el comportamiento de la transferencia de masa. Conocer tanto la velocidad como el tamaño de burbuja, ayudan a caracterizar estos sistemas, llevando un mejor diseño de reactores a gran escala.

  17. Niobium carbide synthesis by solid-gas reaction using a rotating cylinder reactor

    International Nuclear Information System (INIS)

    Fontes, F.A.O.; Gomes, K.K.P.; Oliveira, S.A.; Souza, C.P.; Sousa, J.F.; Rio Grande do Norte Univ., Natal, RN

    2004-01-01

    A rotating cylinder reactor was designed for the synthesis of niobium carbide powders at 1173 K. Niobium carbide, NbC, was prepared by carbothermal reduction starting from commercial niobium pentoxide powders. The reactor was heated using a custom-made, two-part, hinged, electric furnace with programmable temperature control. The design and operational details of the reactor are presented. The longitudinal temperature gradient inside the reactor was determined. Total reaction time was monitored by a gas chromatograph equipped with an FID detector for determination of methane concentrations. The results show that time of reaction depended on rotation speed. NbC was also prepared in a static-bed alumina reactor using the same conditions as in the previous case. The niobium carbide powders were characterized by X-ray diffraction and compared with commercially available products. Morphological, particle size distribution and surface area analyses were obtained using SEM, LDPS and BET, respectively. Therefore, the present study offers a significant technological contribution to the synthesis of NbC powders in a rotating cylinder reactor. (author)

  18. Chapter 3. Determination of semivolatile organic compounds and polycyclic aromatic hydrocarbons in solids by gas chromatography/mass spectrometry

    Science.gov (United States)

    Zaugg, Steven D.; Burkhardt, Mark R.; Burbank, Teresa L.; Olson, Mary C.; Iverson, Jana L.; Schroeder, Michael P.

    2006-01-01

    A method for the determination of 38 polycyclic aromatic hydrocarbons (PAHs) and semivolatile organic compounds in solid samples is described. Samples are extracted using a pressurized solvent extraction system. The compounds of interest are extracted from the solid sample twice at 13,800 kilopascals; first at 120 degrees Celsius using a water/isopropyl alcohol mixture (50:50, volume-to-volume ratio), and then the sample is extracted at 200 degrees Celsius using a water/isopropyl alcohol mixture (80:20, volume-to-volume ratio). The compounds are isolated using disposable solid-phase extraction (SPE) cartridges containing divinylbenzene-vinylpyrrolidone copolymer resin. The cartridges are dried with nitrogen gas, and then sorbed compounds are eluted from the SPE material using a dichloromethane/diethyl ether mixture (80:20, volume-to-volume ratio) and passed through a sodium sulfate/Florisil SPE cartridge to remove residual water and to further clean up the extract. The concentrated extract is solvent exchanged into ethyl acetate and the solvent volume reduced to 0.5 milliliter. Internal standard compounds are added prior to analysis by capillary-column gas chromatography/mass spectrometry. Comparisons of PAH data for 28 sediment samples extracted by Soxhlet and the accelerated solvent extraction (ASE) method described in this report produced similar results. Extraction of PAH compounds from standard reference material using this method also compared favorably with Soxhlet extraction. The recoveries of PAHs less than molecular weight 202 (pyrene or fluoranthene) are higher by up to 20 percent using this ASE method, whereas the recoveries of PAHs greater than or equal to molecular weight 202 are equivalent. This ASE method of sample extraction of solids has advantages over conventional Soxhlet extraction by increasing automation of the extraction process, reducing extraction time, and using less solvent. Extract cleanup also is greatly simplified because SPE replaces

  19. An Overview of Natural Gas Conversion Technologies for Co-Production of Hydrogen and Value-Added Solid Carbon Products

    Energy Technology Data Exchange (ETDEWEB)

    Dagle, Robert A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dagle, Vanessa [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bearden, Mark D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Holladay, Jamelyn D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Krause, Theodore R. [Argonne National Lab. (ANL), Argonne, IL (United States); Ahmed, Shabbir [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-11-16

    This report was prepared in response to the U.S. Department of Energy Fuel Cell Technologies Office Congressional Appropriation language to support research on carbon-free production of hydrogen using new chemical processes that utilize natural gas to produce solid carbon and hydrogen. The U.S. produces 9-10 million tons of hydrogen annually with more than 95% of the hydrogen produced by steam-methane reforming (SMR) of natural gas. SMR is attractive because of its high hydrogen yield; but it also converts the carbon to carbon dioxide. Non-oxidative thermal decomposition of methane to carbon and hydrogen is an alternative to SMR and produces CO2-free hydrogen. The produced carbon can be sold as a co-product, thus providing economic credit that reduces the delivered net cost of hydrogen. The combination of producing hydrogen with potentially valuable carbon byproducts has market value in that this allows greater flexibility to match the market prices of hydrogen and carbon. That is, the higher value product can subsidize the other in pricing decisions. In this report we highlight the relevant technologies reported in the literature—primarily thermochemical and plasma conversion processes—and recent research progress and commercial activities. Longstanding technical challenges include the high energetic requirements (e.g., high temperatures and/or electricity requirements) necessary for methane activation and, for some catalytic processes, the separation of solid carbon product from the spent catalyst. We assess current and new carbon product markets that could be served given technological advances, and we discuss technical barriers and potential areas of research to address these needs. We provide preliminary economic analysis for these processes and compare to other emerging (e.g., electrolysis) and conventional (e.g., SMR) processes for hydrogen production. The overarching conclusion of this study is that the cost of hydrogen can be potentially

  20. Performance Characterization of Gas-Solid Cyclone for Separation of Particle from Syngas Produced from Food Waste Gasifier Plant

    Directory of Open Access Journals (Sweden)

    Osezua O. Ibhadode

    2017-06-01

    Full Text Available A biofuel from any biodegradable formation process such as a food waste bio-digester plant is a mixture of several gases such as methane (CH4, carbon dioxide (CO2, hydrogen sulfide (H2S, ammonia (NH3 and impurities like water and dust particles. The results are reported of a parametric study of the process of separation of methane, which is the most important gas in the mixture and usable as a biofuel, from particles and H2S. A cyclone, which is a conventional, economic and simple device for gas-solid separation, is considered based on the modification of three Texas A&M cyclone designs (1D2D, 2D2D and 1D3D by the inclusion of an air inlet tube. A parametric sizing is performed of the cyclone for biogas purification, accounting for the separation of hydrogen sulfide (H2S and dust particles from the biofuel. The stochiometric oxidation of H2S to form elemental sulphur is considered a useful cyclone design criterion. The proposed design includes geometric parameters and several criteria for quantifying the performance of cyclone separators such as the Lapple Model for minimum particle diameter collected, collection efficiency and pressure drop. For biogas volumetric flow rates between 0 and 1 m/s and inlet flow velocities of 12 m/s, 15 m/s and 18 m/s for the 1D2D, 2D2D and 1D3D cyclones, respectively, it is observed that the 2D2D configuration is most economic in terms of sizing (total height and diameter of cyclone. The 1D2D configuration experiences the lowest pressure drop. A design algorithm coupled with a user-friendly graphics interface is developed on the MATLAB platform, providing a tool for sizing and designing suitable cyclones.

  1. Greenhouse gas emissions from different municipal solid waste management scenarios in China: Based on carbon and energy flow analysis.

    Science.gov (United States)

    Liu, Yili; Sun, Weixin; Liu, Jianguo

    2017-10-01

    Waste management is a major source of global greenhouse gas (GHG) emissions and many opportunities exist to reduce these emissions. To identify the GHG emissions from waste management in China, the characteristics of MSW and the current and future treatment management strategies, five typical management scenarios were modeled by EaseTech software following the principles of life cycle inventory and analyzed based on the carbon and energy flows. Due to the high organic fraction (50-70%) and moisture content (>50%) of Chinese municipal solid waste (MSW), the net GHG emissions in waste management had a significant difference from the developed countries. It was found that the poor landfill gas (LFG) collection efficiency and low carbon storage resulted landfilling with flaring and landfilling with biogas recovery scenarios were the largest GHG emissions (192 and 117 kgCO 2 -Eq/t, respectively). In contrast, incineration had the best energy recovery rate (19%), and, by grid emissions substitution, led to a substantial decrease in net GHG emissions (-124 kgCO 2 -Eq/t). Due to the high energy consumption in operation, the unavoidable leakage of CH 4 and N 2 O in treatment, and the further release of CH 4 in disposing of the digested residue or composted product, the scenarios with biological treatment of the organic fractions after sorting, such as composting or anaerobic digestion (AD), did not lead to the outstanding GHG reductions (emissions of 32 and -36 kgCO 2 -Eq/t, respectively) as expected. Copyright © 2017. Published by Elsevier Ltd.

  2. Eco-efficiency for greenhouse gas emissions mitigation of municipal solid waste management: a case study of Tianjin, China.

    Science.gov (United States)

    Zhao, Wei; Huppes, Gjalt; van der Voet, Ester

    2011-06-01

    The issue of municipal solid waste (MSW) management has been highlighted in China due to the continually increasing MSW volumes being generated and the limited capacity of waste treatment facilities. This article presents a quantitative eco-efficiency (E/E) analysis on MSW management in terms of greenhouse gas (GHG) mitigation. A methodology for E/E analysis has been proposed, with an emphasis on the consistent integration of life cycle assessment (LCA) and life cycle costing (LCC). The environmental and economic impacts derived from LCA and LCC have been normalized and defined as a quantitative E/E indicator. The proposed method was applied in a case study of Tianjin, China. The study assessed the current MSW management system, as well as a set of alternative scenarios, to investigate trade-offs between economy and GHG emissions mitigation. Additionally, contribution analysis was conducted on both LCA and LCC to identify key issues driving environmental and economic impacts. The results show that the current Tianjin's MSW management system emits the highest GHG and costs the least, whereas the situation reverses in the integrated scenario. The key issues identified by the contribution analysis show no linear relationship between the global warming impact and the cost impact in MSW management system. The landfill gas utilization scenario is indicated as a potential optimum scenario by the proposed E/E analysis, given the characteristics of MSW, technology levels, and chosen methodologies. The E/E analysis provides an attractive direction towards sustainable waste management, though some questions with respect to uncertainty need to be discussed further. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Life cycle assessment of municipal solid waste management with regard to greenhouse gas emissions: Case study of Tianjin, China

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Wei [School of Environmental Science and Engineering, Tianjin University, Weijin Road 92, Nankai District 300072 (China); Institute of Environmental Sciences (CML), Leiden University, P. O. Box 9518, 2300RA, Leiden (Netherlands)], E-mail: zhao@cml.leidenuniv.nl; Voet, Ester van der [Institute of Environmental Sciences (CML), Leiden University, P. O. Box 9518, 2300RA, Leiden (Netherlands); Zhang Yufeng [School of Environmental Science and Engineering, Tianjin University, Weijin Road 92, Nankai District 300072 (China); Huppes, Gjalt [Institute of Environmental Sciences (CML), Leiden University, P. O. Box 9518, 2300RA, Leiden (Netherlands)

    2009-02-15

    The environmental impacts of municipal solid waste (MSW) management have been highlighted in China, due to the continually increasing amount of MSW being generated and the limited capacity of waste treatment facilities. Of particular interest is greenhouse gas (GHG) mitigation, aided by the Kyoto Mechanisms. China is an important case study for this global issue; however, an analysis of the entire life cycle of MSW management on GHG emissions is not available for China. This study evaluates the current and possible patterns of MSW management with regard to GHG emissions, using life cycle assessment (LCA), based on the Tianjin case. We assess the baseline scenario, reflecting the existing MSW management system, as well as a set of alternative scenarios, five exploring waste treatment technology innovations and one exploring integrated MSW management, to quantitatively predict potentials of GHG mitigation for Tianjin. Additionally, a sensitivity analysis is used to investigate the influence of landfill gas (LFG) collection efficiency, recycling rate and methodological choice, especially allocation, on the outcomes. The results show GHG emissions from Tianjin's MSW management system amount to 467.34 Mg CO{sub 2} eq. per year, based on the treatment of MSW collected in the central districts in 2006, and the key issue is LFG released. The integrated MSW management scenario, combining different improvement options, shows the highest GHG mitigation potential. Given the limited financial support and the current waste management practice in Tianjin, LFG utilization scenario would be the preferred choice. The sensitivity analysis of recycling rate shows an approximately linear relation of inverse proportion between recycling rate and total GHG emissions. Kitchen waste composting makes a considerable contribution to total GHG emissions reduction. Allocation choices result in differences in total quantitative outcomes, but preference orders and contributions analysis are

  4. Life cycle assessment of municipal solid waste management with regard to greenhouse gas emissions: Case study of Tianjin, China

    International Nuclear Information System (INIS)

    Zhao Wei; Voet, Ester van der; Zhang Yufeng; Huppes, Gjalt

    2009-01-01

    The environmental impacts of municipal solid waste (MSW) management have been highlighted in China, due to the continually increasing amount of MSW being generated and the limited capacity of waste treatment facilities. Of particular interest is greenhouse gas (GHG) mitigation, aided by the Kyoto Mechanisms. China is an important case study for this global issue; however, an analysis of the entire life cycle of MSW management on GHG emissions is not available for China. This study evaluates the current and possible patterns of MSW management with regard to GHG emissions, using life cycle assessment (LCA), based on the Tianjin case. We assess the baseline scenario, reflecting the existing MSW management system, as well as a set of alternative scenarios, five exploring waste treatment technology innovations and one exploring integrated MSW management, to quantitatively predict potentials of GHG mitigation for Tianjin. Additionally, a sensitivity analysis is used to investigate the influence of landfill gas (LFG) collection efficiency, recycling rate and methodological choice, especially allocation, on the outcomes. The results show GHG emissions from Tianjin's MSW management system amount to 467.34 Mg CO 2 eq. per year, based on the treatment of MSW collected in the central districts in 2006, and the key issue is LFG released. The integrated MSW management scenario, combining different improvement options, shows the highest GHG mitigation potential. Given the limited financial support and the current waste management practice in Tianjin, LFG utilization scenario would be the preferred choice. The sensitivity analysis of recycling rate shows an approximately linear relation of inverse proportion between recycling rate and total GHG emissions. Kitchen waste composting makes a considerable contribution to total GHG emissions reduction. Allocation choices result in differences in total quantitative outcomes, but preference orders and contributions analysis are found to

  5. Experimental and theoretical characterization of a multi-wavelength DBD-driven exciplex lamp operated with mercury bromide/rare gas mixtures

    International Nuclear Information System (INIS)

    Guivan, Mykola M; Malinina, Antonina A; Brablec, Antonin

    2011-01-01

    Emission spectra from an atmospheric-pressure dielectric barrier discharge (DBD) with HgBr 2 /He or HgBr 2 /Xe/Kr mixtures, as well as the electrical characteristics, were investigated at repetition frequencies of sinusoidal voltage pulses up to 125 kHz. In the spectra, the study revealed radiation from HgBr(B-X, C-X) exciplex molecules, atomic lines of mercury and rare gases, and in mixtures with xenon, radiation of XeBr(B-X, B-A) exciplex molecules. Regularities in the spectral characteristics of the radiation from the gas-discharge plasma were discussed. The electron energy distribution function, the specific energy lost in the processes involving electrons, the electron temperature and density, and the rate constants of elastic and inelastic electron scattering by the components of the working mixture were calculated as functions of the reduced field E/N. The high-frequency atmospheric-pressure barrier discharge in mixtures of mercury dibromide with gases can be used in multi-wavelength exciplex lamps, operating in the UV and visible regions.

  6. Effects of anisotropic interaction-induced properties of hydrogen-rare gas compounds on rototranslational Raman scattering spectra: Comprehensive theoretical and numerical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Głaz, Waldemar, E-mail: glaz@kielich.amu.edu.pl; Bancewicz, Tadeusz [Nonlinear Optics Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); Godet, Jean-Luc [Laboratoire de Photonique d’Angers, Université d’Angers, 2 Boulevard Lavoisier, 49045 Angers (France); Gustafsson, Magnus [Department of Engineering Sciences and Mathematics, Luleå University of Technology, SE-97187 Luleå (Sweden); Haskopoulos, Anastasios; Maroulis, George [Department of Chemistry, University of Patras, GR-26500 Patras (Greece)

    2016-07-21

    A comprehensive study is presented of many aspects of the depolarized anisotropic collision induced (CI) component of light scattered by weakly bound compounds composed of a dihydrogen molecule and a rare gas (Rg) atom, H{sub 2}–Rg. The work continues a series of earlier projects marking the revival of interest in linear light scattering following the development of new highly advanced tools of quantum chemistry and other theoretical, computational, and experimental means of spectral analyses. Sophisticated ab initio computing procedures are applied in order to obtain the anisotropic polarizability component’s dependence on the H{sub 2}–Rg geometry. These data are then used to evaluate the CI spectral lines for all types of Rg atoms ranging from He to Xe (Rn excluded). Evolution of the properties of CI spectra with growing polarizability/masses of the complexes studied is observed. Special attention is given to the heaviest, Kr and Xe based, scatterers. The influence of specific factors shaping the spectral lines (e.g., bound and metastable contribution, potential anisotropy) is discussed. Also the share of pressure broadened allowed rotational transitions in the overall spectral profile is taken into account and the extent to which it is separable from the pure CI contribution is discussed. We finish with a brief comparison between the obtained results and available experimental data.

  7. Comparative study of energy of particles ejected from coulomb explosion of rare gas and metallic clusters irradiated by intense femtosecond laser field

    Science.gov (United States)

    Boucerredj, N.; Beggas, K.

    2016-10-01

    We present our study of high intensity femtosecond laser field interaction with large cluster of Kr and Na (contained 2.103 to 2.107 atoms). When laser intensity is above a critical value, it blows off all of electrons from the cluster and forms a non neutral ion cloud. The irradiation of these clusters by the intense laser field leads to highly excitation energy which can be the source of energetic electrons, electronic emission, highly charge, energetic ions and fragmentation process. During the Coulomb explosion of the resulting highly ionized, high temperature nanoplasma, ions acquire again their energy. It is shown that ultra fast ions are produced. The goal of our study is to investigate in detail a comparative study of the expansion and explosion then the ion energy of metallic and rare gas clusters irradiated by an intense femtosecond laser field. We have found that ions have a kinetic energy up to 105 eV and the Coulomb pressure is little than the hydrodynamic pressure. The Coulomb explosion of a cluster may provide a new high energy ion source.

  8. Experimental and theoretical characterization of a multi-wavelength DBD-driven exciplex lamp operated with mercury bromide/rare gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Guivan, Mykola M; Malinina, Antonina A [Department of Quantum Electronics, Uzhgorod National University, Pidgirna 46, Uzhgorod 88000 (Ukraine); Brablec, Antonin, E-mail: m_guivan@rambler.ru [Department of Physical Electronics, Masaryk University, Kotlarska 2, Brno 61137 (Czech Republic)

    2011-06-08

    Emission spectra from an atmospheric-pressure dielectric barrier discharge (DBD) with HgBr{sub 2}/He or HgBr{sub 2}/Xe/Kr mixtures, as well as the electrical characteristics, were investigated at repetition frequencies of sinusoidal voltage pulses up to 125 kHz. In the spectra, the study revealed radiation from HgBr(B-X, C-X) exciplex molecules, atomic lines of mercury and rare gases, and in mixtures with xenon, radiation of XeBr(B-X, B-A) exciplex molecules. Regularities in the spectral characteristics of the radiation from the gas-discharge plasma were discussed. The electron energy distribution function, the specific energy lost in the processes involving electrons, the electron temperature and density, and the rate constants of elastic and inelastic electron scattering by the components of the working mixture were calculated as functions of the reduced field E/N. The high-frequency atmospheric-pressure barrier discharge in mixtures of mercury dibromide with gases can be used in multi-wavelength exciplex lamps, operating in the UV and visible regions.

  9. Rare gas dependence of vibration--vibration energy transfer processes: A diagnostic technique. Applications to CH2D2 and CH3F

    International Nuclear Information System (INIS)

    Apkarian, V.A.; Weitz, E.

    1979-01-01

    The rare gas dependence of V--V rates can be used as a diagnostic technique to identify different mechanisms of vibrational energy transfer and determine the rate constants for individual kinetic steps. The method is especially useful for the identification and measurement of rates of resonant vibrational energy transfer processes. Analytical and numerical solutions of pertinent model equations are presented and their range of applicability is discussed. The technique is applied to CH 2 D 2 and CH 3 F. In CH 2 D 2 results of studies on ν 9 , [ν 1 , ν 6 ] and states in the 2000 cm -1 region are presented where the application of the technique has made it possible to identify the pathways leading to population of these states and to assign rate constants to some of the steps involved. In CH 3 F, by studying the Ar dependence of the V--V rates of the [ν 2 , ν 5 ] and [ν 1 , ν 4 ] states it has been possible to construct a complete map of energy transfer pathways which can explain all experimental observations for this system, to date. The general applicability of the technique and its potential application to other systems is also considered

  10. Theoretical study of the interaction between intense laser pulses and rare gas clusters; Etude theorique de l'interaction entre une impulsion laser intense et un agregat de gaz rare

    Energy Technology Data Exchange (ETDEWEB)

    Micheau, S

    2007-07-15

    The irradiation of nanometer-scale rare gas clusters by a short (a few hundreds of femtosecond) and intense (I > 10{sup 15} W/cm{sup 2}) laser pulse yields multi-keV short X-ray bursts. We employ an hydrodynamic model, the so-called 'nano-plasma model', to understand the mechanisms that tailor the interaction. In this model, the cluster is treated as a dielectric sphere embedded in the quasi-static laser field leading to the formation of a plasma of nano-metric size. We have shown that this model cannot reproduce the experimental results such as the high ionization states and associated X-ray spectra. We have thus included in the model two additional mechanisms that significantly improve the ionization dynamics. First, we have introduced high order ionization processes involving intermediate excited states X{sup q+} + e{sup -} {yields} X{sup q+*} + e{sup -} {yields}... {yields} X{sup q+1+} + 2 e{sup -}. We have used a model potential approach to describe the electronic structure of the cluster's ions (and atoms), and we have computed the total excitation and ionization cross-sections in the distorted-wave Born approximation. Secondly we have studied the influence of screening phenomena induced by the electronic density on the interaction dynamics. By using a sophisticated potential, we have shown that screening effects enhance ionization and lower excitation cross sections with respect to the unscreened data. The improved nano-plasma model allows us to reproduce the populations of highly charged states experimentally observed, and the variation of argon He{sub {alpha}} emission with respect to the various experimental parameters (cluster size, laser pulse duration, intensity and wavelength). We have further computed time- and energy-resolved X-ray spectra which emphasize ultra-short emission duration (less than 100 fs), and therefore indicate that cluster-based X-ray sources are adequate to ultrafast X-ray science applications. (author)

  11. Upgraded biogas from municipal solid waste for natural gas substitution and CO2 reduction--a case study of Austria, Italy, and Spain.

    Science.gov (United States)

    Starr, Katherine; Villalba, Gara; Gabarrell, Xavier

    2015-04-01

    Biogas is rich in methane and can be further purified through biogas upgrading technologies, presenting a viable alternative to natural gas. Landfills and anaerobic digestors treating municipal solid waste are a large source of such biogas. They therefore offer an attractive opportunity to tap into this potential source of natural gas while at the same time minimizing the global warming impact resulting from methane emissions in waste management schemes (WMS) and fossil fuel consumption reduction. This study looks at the current municipal solid waste flows of Spain, Italy, and Austria over one year (2009), in order to determine how much biogas is generated. Then it examines how much natural gas could be substituted by using four different biogas upgrading technologies. Based on current waste generation rates, exploratory but realistic WMS were created for each country in order to maximize biogas production and potential for natural gas substitution. It was found that the potential substitution of natural gas by biogas resulting from the current WMS seems rather insignificant: 0.2% for Austria, 0.6% for Italy and 0.3% for Spain. However, if the WMS is redesigned to maximize biogas production, these figures can increase to 0.7% for Austria, 1% for Italy and 2% for Spain. Furthermore, the potential CO2 reduction as a consequence of capturing the biogas and replacing fossil fuel can result in up to a 93% reduction of the annual national waste greenhouse gas emissions of Spain and Italy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Thermodynamic Modeling of a Solid Oxide Fuel Cell to Couple with an Existing Gas Turbine Engine Model

    Science.gov (United States)

    Brinson, Thomas E.; Kopasakis, George

    2004-01-01

    The Controls and Dynamics Technology Branch at NASA Glenn Research Center are interested in combining a solid oxide fuel cell (SOFC) to operate in conjunction with a gas turbine engine. A detailed engine model currently exists in the Matlab/Simulink environment. The idea is to incorporate a SOFC model within the turbine engine simulation and observe the hybrid system's performance. The fuel cell will be heated to its appropriate operating condition by the engine s combustor. Once the fuel cell is operating at its steady-state temperature, the gas burner will back down slowly until the engine is fully operating on the hot gases exhausted from the SOFC. The SOFC code is based on a steady-state model developed by The U.S. Department of Energy (DOE). In its current form, the DOE SOFC model exists in Microsoft Excel and uses Visual Basics to create an I-V (current-voltage) profile. For the project's application, the main issue with this model is that the gas path flow and fuel flow temperatures are used as input parameters instead of outputs. The objective is to create a SOFC model based on the DOE model that inputs the fuel cells flow rates and outputs temperature of the flow streams; therefore, creating a temperature profile as a function of fuel flow rate. This will be done by applying the First Law of Thermodynamics for a flow system to the fuel cell. Validation of this model will be done in two procedures. First, for a given flow rate the exit stream temperature will be calculated and compared to DOE SOFC temperature as a point comparison. Next, an I-V curve and temperature curve will be generated where the I-V curve will be compared with the DOE SOFC I-V curve. Matching I-V curves will suggest validation of the temperature curve because voltage is a function of temperature. Once the temperature profile is created and validated, the model will then be placed into the turbine engine simulation for system analysis.

  13. Determination of Parabens by Injection-Port Derivatization Coupled With Gas-Chromatography-Mass Spectrometry and Matrix Solid Phase Dispersion

    Science.gov (United States)

    Djatmika, Rosalina; Ding, Wang-Hsien; Sulistyarti, Hermin

    2018-01-01

    A rapid determination of four parabens preservatives (methyl paraben, ethyl paraben, propyl paraben, and butyl paraben) in marketed seafood is presented. Analytes were extracted and purified using matrix solid-phase dispersion (MSPD) method, followed by Injection port acylation gas chromatography-mass spectrometry (GC-MS) with acetic anhydride reagent. In this method, acylation of parabens was performed by acetic anhydride at GC injection-port generating reduction of the time-consuming sample-processing steps, and the amount of toxic reagents and solvents. The parameters affecting this method such as injection port temperature, purge-off time and acylation (acetic anhydride) volume were studied. In addition, the MSPD influence factors (including the amount of dispersant and clean-up co-sorbent, as well as the volume of elution solvent) were also investigated. After MSPD method and Injection port acylation applied, good linearity of analytes was achieved. The limits of quantitation (LOQs) were 0.2 to 1.0 ng/g (dry weight). Compared with offline derivatization commonly performed, injection port acylation employs a rapid, simple, low-cost and environmental-friendly derivatization process. The optimized method has been successfully applied for the analysis of parabens in four kind of marketed seafood. Preliminary results showed that the total concentrations of four selected parabens ranged from 16.7 to 44.7 ng/g (dry weight).

  14. Production of solid lipid submicron particles for protein delivery using a novel supercritical gas-assisted melting atomization process.

    Science.gov (United States)

    Salmaso, Stefano; Elvassore, Nicola; Bertucco, Alberto; Caliceti, Paolo

    2009-02-01

    A supercritical carbon dioxide micronization technique based on gas-assisted melting atomization has been designed to prepare protein-loaded solid lipid submicron particles. The supercritical process was applied to homogeneous dispersions of insulin in lipid mixtures: (1) tristearin, Tween-80, phosphatidylcholine and 5 kDa PEG (1:0.1:0.9:1 and 1:0.1:0.9:2 weight ratio); and (2) tristearin, dioctyl sulfosuccinate and phosphatidylcholine (1:1:0.5 weight ratio). Optimized process conditions yielded dry nonagglomerated powders with high product recovery (70%, w/w). Dynamic light scattering and transmission electron microscopy showed that two size fractions of particles, with 80-120 and 200-400 nm diameters, were produced. In all final products, dimethylsulfoxide used to prepare the insulin/lipid mixture was below 20 ppm. Protein encapsulation efficiency increased up to 80% as the DMSO content in the insulin/lipid mixture increased. Compared to the particles without PEG, the polymer-containing particles dispersed rapidly in water, and the dispersions were more stable under centrifugation as less than 20% of suspended particles precipitated after extensive centrifugation. In vitro, the protein was slowly released from the formulation without PEG, while a burst and faster release were obtained from the formulations containing PEG. Subcutaneous injection to diabetic mice of insulin extracted from the particles showed that the supercritical process did not impair the protein hypoglycemic activity.

  15. Characterization of the volatile profiles of beer using headspace solid-phase microextraction and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Rossi, Serena; Sileoni, Valeria; Perretti, Giuseppe; Marconi, Ombretta

    2014-03-30

    The objective of this study was a multivariate characterization of the volatile profile of beers. Such a characterization is timely considering the increasing worldwide consumption of beer, the continuous growth of microbreweries and the importance of volatile compounds to beer flavour. A method employing solid-phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS) was optimized and then applied to a sample set of 36 industrial and craft beers of various styles and fermentation types. The volatile profiles of different beer styles is described, with particular attention paid to the volatile compounds characteristic of a spontaneously fermented lambic raspberry framboise beer. Furthermore, it was also possible to identify which specific volatile compounds are principally responsible for the differences in the volatile profiles of top- and bottom-fermented beers. Moreover, a volatile fingerprint of the craft top-fermented Italian beers was defined, as they show a very similar volatile profile. Finally, the volatile compounds that are characteristic of the bock-style beers are described. The SPME-GC-MS analytical method optimized in this study is suitable for characterizing the volatile fingerprint of different beers, especially on the basis of the kind of fermentation (top, bottom or spontaneous), the method of production and the style of the beer. © 2013 Society of Chemical Industry.

  16. Solid oxide fuel cell/gas turbine hybrid system analysis for high-altitude long-endurance unmanned aerial vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, P.; Brandon, N.P. [Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ (United Kingdom); Brett, D.J.L. [The Centre for CO{sub 2} Technology, University College London, London WC1E 7JE (United Kingdom)

    2008-12-15

    High-altitude long-endurance (HALE) unmanned aerial vehicles (UAVs) are ideally suited to provide surveillance, remote sensing and communication relay capabilities for both military and civilian applications. HALE UAVs typically cruise at an altitude between 15 km and 20 km, travelling at low speed and circling specific areas of interest. The work reported aims to investigate alternative power system architectures that enable an efficiency increase and consequent fuel consumption reduction to realise a one-week endurance target. Specifically, the application of a solid oxide fuel cell combined with a gas turbine is considered; with different system configurations modelled with a view to maximising overall efficiency. It is found that modularising the fuel cell capacity into a number of discrete stacks such that the fuel is distributed in parallel and air is fed in series results in an increased system efficiency compared with a single-stack design. An overall system efficiency of 66.3% (LHV) when operating on hydrogen is predicted for a three-stack system. (author)

  17. Hydrothermal solid-gas route to TiO2 nanoparticles/nanotube arrays for high-performance supercapacitors

    Science.gov (United States)

    Fan, Haowen; Zhang, He; Luo, Xiaolei; Liao, Maoying; Zhu, Xufei; Ma, Jing; Song, Ye

    2017-07-01

    Although TiO2 nanotube arrays (TNTAs) have shown great promise as supercapacitor materials, their specific capacitances are still not comparable with some typical materials. Here, TiO2 nanoparticles (NPs)/TNTAs hybrid structure has been derived from the anodized TNTAs by a facile hydrothermal solid-gas method (HSGM), which can avoid cracking or curling of the TNTAs from Ti substrate. The obtained NPs/TNTAs hybrid structure can exhibit a ∼4.90 times increase in surface area and a ∼5.49 times increase in areal specific capacitance compared to the TNTAs without HSGM treatment. Besides, the argon-atmosphere annealing can offer improved areal capacitance and cycling stability relative to the air-atmosphere annealing. The hydrothermal vapor pressure is a key factor for controlling microscopic morphologies of TNTAs, the morphology transformations of TNTAs during the HSGM treatment can be accelerated under enhanced vapor pressures. The highest areal capacitance of HSGM-treated TNTAs is up to 76.12 mF cm-2 at 0.5 mA cm-2, well above that of any TiO2 materials reported to date.

  18. Greenhouse gas accounting of the proposed landfill extension and advanced incineration facility for municipal solid waste management in Hong Kong.

    Science.gov (United States)

    Woon, K S; Lo, Irene M C

    2013-08-01

    The burgeoning of municipal solid waste (MSW) disposal issue and climate change have drawn massive attention from people. On the one hand, Hong Kong is facing a controversial debate over the implementation of proposed landfill extension (LFE) and advanced incineration facility (AIF) to curb the MSW disposal issue. On the other hand, the Hong Kong Special Administrative Region Government is taking concerted efforts to reduce the carbon intensity in this region. This paper discusses the greenhouse gas (GHG) emissions from four proposed waste disposal scenarios, covering the proposed LFE and AIF within a defined system boundary. On the basis of the data collected, assumptions made, and system boundary defined in this study, the results indicate that AIF releases less GHG emissions than LFE. The GHG emissions from LFE are highly contributed by the landfill methane (CH4) emissions but offset by biogenic carbon storage, while the GHG emissions from AIF are mostly due to the stack discharge system but offset by the energy recovery system. Furthermore, parametric sensitivity analyses show that GHG emissions are strongly dependent on the landfill CH4 recovery rate, types of electricity displaced by energy recovery systems, and the heating value of MSW, altering the order of preferred waste disposal scenarios. This evaluation provides valuable insights into the applicability of a policy framework for MSW management practices in reducing GHG emissions. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Direct solid phase microextraction combined with gas chromatography - Mass spectrometry for the determination of biogenic amines in wine.

    Science.gov (United States)

    Papageorgiou, Myrsini; Lambropoulou, Dimitra; Morrison, Calum; Namieśnik, Jacek; Płotka-Wasylka, Justyna

    2018-06-01

    A direct method based on immersion solid phase microextraction (DI-SPME) gas chromatography mass-spectrometry (GC-MS) was optimized and validated for the determination of 16 biogenic amines in Polish wines. In the analysis two internal standards were used: 1,7-diaminoheptane and bis-3-aminopropylamine. The method allows for simultaneous extraction and derivatization, providing a simple and fast mode of extraction and enrichment. Different parameters which affect the extraction procedure were studied and optimized including ionic strength (0-25%), fiber materials (PDMS/DVB, PDMS/DVD + OC, Polyacrylate, Carboxen/PDMS and DVB/CAR/PDMS) and timings of the extraction, derivatization and desorption processes. Validation studies confirmed the linearity, sensitivity, precision and accuracy of the method. The method was successfully applied to the analysis of 44 wine samples originating from several regions of Poland and 3 wine samples from other countries. Analysis showed that many of the samples contained all examined biogenic amines. The method, assessed using an Eco-Scale tool with satisfactory results, was found to be green in terms of hazardous chemicals and solvents usage, energy consumption and production of waste. Therefore the proposed method can be safely used in the wine industry for routine analysis of BAs in wine samples with a minimal detrimental impact on human health and the environment. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Determination of roasted pistachio (Pistacia vera L.) key odorants by headspace solid-phase microextraction and gas chromatography-olfactometry.

    Science.gov (United States)

    Aceña, Laura; Vera, Luciano; Guasch, Josep; Busto, Olga; Mestres, Montserrat

    2011-03-23

    Key odorants in roasted pistachio nuts have been determined for the first time. Two different pistachio varieties (Fandooghi and Kerman) have been analyzed by means of headspace solid-phase microextraction (HS-SPME) and gas chromatography-olfactometry (GCO). The aroma extract dilution analyses (AEDA) applied have revealed 46 and 41 odor-active regions with a flavor dilution (FD) factor≥64 for the Fandooghi and the Kerman varieties, respectively, and 39 of them were related to precisely identified compounds. These included esters, pyrazines, aldehydes, acids, furans, and phenols. The results show that the Fandooghi variety presents, not only more odor-active regions but also higher FD factors than the Kerman variety that can lead to the conclusion that the first variety has a richer aromatic profile than the second one. The descriptive sensory analysis (DSA) showed that the roasted, chocolate/coffee, and nutty attributes were rated significantly higher in the Fandooghi variety, whereas the green attribute was significantly higher in the Kerman one.