WorldWideScience

Sample records for evolved gas analysis

  1. Possible Detection of Perchlorates by Evolved Gas Analysis of Rocknest Soils: Global Implication

    Science.gov (United States)

    Archer, P. D., Jr.; Sutter, B.; Ming, D. W.; McKay, C. P.; Navarro-Gonzalez, R.; Franz, H. B.; McAdam, A.; Mahaffy, P. R.

    2013-01-01

    The Sample Analysis at Mars (SAM) instrument suite on board the Mars Science Laboratory (MSL) recently ran four samples from an aeolian bedform named Rocknest. Rocknest was selected as the source of the first samples analyzed because it is representative of both windblown material in Gale crater as well as the globally-distributed dust. The four samples analyzed by SAM were portioned from the fifth scoop at this location. The material delivered to SAM passed through a 150 m sieve and should have been well mixed during the sample acquisition/ preparation/handoff process. Rocknest samples were heated to 835 C at a 35 C/minute ramp rate with a He carrier gas flow rate of 1.5 standard cubic centimeters per minute and at an oven pressure of 30 mbar. Evolved gases were detected by a quadrupole mass spectrometer (QMS).

  2. Oxidation and cyclization of organics in Mars-like soils during evolved gas analysis

    Science.gov (United States)

    Navarro-Gonzalez, Rafael; Iñiguez, Enrique; de La Rosa, Jose; McKay, Chris

    Thermal volatilization (TV) of soils has been used as the method of choice in space because of its simplicity and reproducibility. TV was first used by the Viking Landers, which failed to detect organics at ppb levels and subsequently by the Phoenix Lander that did not find organics but instead detected the release of carbon dioxide from 400 to 680° C which was attributed to magnesium or iron carbonate, adsorbed carbon dioxide, or organics present in the soil. Future missions such as the Mars Science Laboratory from NASA and ExoMars from ESA will also use this method to release soil organics to the analytical instruments. The presence of inorganic salts or minerals can strongly modify the release of soil organics leading to their degradation and/or oxidation resulting in loss of sensitivity by several orders of magnitude. The purpose of this work is to study the matrix effects of some minerals and Martian soil analogues in the analysis of organics by TV. Samples were analyzed by TV-MS and/or TV-GC-MS in neutral (He) and reducing (H2 ) atmospheres following the methods reported by Navarro-González eta al., 2006, 2009 and Iñiguez et al., 2009. Our results show that oxidation of organic matter is n promoted by several soil minerals (iron oxides) and inorganic salts (perchlorates, persulphates, sulfates, nitrates) in a neutral atmosphere; however, in a reducing atmosphere the oxidation of organics by the mineral matrix is reduced. Furthermore it was found that the stable organics that were thermally evolved were aromatic in nature (benzene and methyl benzene). Therefore, depending on the mineral matrix there is completion between formation of aromatic compounds versus oxidation. Iñiguez, E., Navarro-González, R., de la Rosa, J., Ureña-Núnez, F., Coll, P., Raulin, F., and McKay, C.P.: 2009, On the oxidation ability of the NASA Mars-1 soil simulant during the thermal volatilization step. Implications for the search of organics on Mars. Geophys Res Lett 36, L21205

  3. Evolved Gas Analyses of the Murray Formation in Gale Crater, Mars: Results of the Curiosity Rover's Sample Analysis at Mars (SAM) Instrument

    Science.gov (United States)

    Sutter, B.; McAdam, A. C.; Rampe, E. B.; Thompson, L. M.; Ming, D. W.; Mahaffy, P. R.; Navarro-Gonzalez, R.; Stern, J. C.; Eigenbrode, J. L.; Archer, P. D.

    2017-01-01

    The Sample Analysis at Mars (SAM) instrument aboard the Mars Science Laboratory rover has analyzed 13 samples from Gale Crater. All SAM-evolved gas analyses have yielded a multitude of volatiles (e.g., H2O, SO2, H2S, CO2, CO, NO, O2, HCl) [1- 6]. The objectives of this work are to 1) Characterize recent evolved SO2, CO2, O2, and NO gas traces of the Murray formation mudstone, 2) Constrain sediment mineralogy/composition based on SAM evolved gas analysis (SAM-EGA), and 3) Discuss the implications of these results relative to understanding the geological history of Gale Crater.

  4. Evolved Gas Analyses of Sedimentary Materials in Gale Crater, Mars: Results of the Curiosity Rover's Sample Analysis at Mars (SAM) Instrument from Yellowknife Bay to the Stimson Formation

    Science.gov (United States)

    Sutter, B.; McAdam, A. C.; Rampe, E. B.; Ming, D. W.; Mahaffy, P. R.; Navarro-Gonzalez, R.; Stern, J. C.; Eigenbrode, J. L.; Archer, P. D.

    2016-01-01

    The Sample Analysis at Mars (SAM) instrument aboard the Mars Science Laboratory rover has analyzed 10 samples from Gale Crater. All SAM evolved gas analyses have yielded a multitude of volatiles (e.g, H2O, SO2, H2S, CO2, CO, NO, O2, HC1). The objectives of this work are to 1) Characterize the evolved H2O, SO2, CO2, and O2 gas traces of sediments analyzed by SAM through sol 1178, 2) Constrain sediment mineralogy/composition based on SAM evolved gas analysis (SAM-EGA), and 3) Discuss the implications of these results releative to understanding the geochemical history of Gale Crater.

  5. Thermal and Evolved Gas Analysis of Calcite Under Reduced Operating Pressures: Implications for the 2011 MSL Sample Analysis at Mars (SAM) Instrument

    Science.gov (United States)

    Lauer, H. V. Jr.; Ming, D. W.; Sutter, B.; Mahaffy, P. R.

    2010-01-01

    The Mars Science Laboratory (MSL) is scheduled for launch in 2011. The science objectives for MSL are to assess the past or present biological potential, to characterize the geology, and to investigate other planetary processes that influence habitability at the landing site. The Sample Analysis at Mars (SAM) is a key instrument on the MSL payload that will explore the potential habitability at the landing site [1]. In addition to searching for organic compounds, SAM will have the capability to characterized evolved gases as a function of increasing temperature and provide information on the mineralogy of volatile-bearing phases such as carbonates, sulfates, phyllosilicates, and Fe-oxyhydroxides. The operating conditions in SAM ovens will be maintained at 30 mb pressure with a He carrier gas flowing at 1 sccm. We have previously characterized the thermal and evolved gas behaviors of volatile-bearing species under reduced pressure conditions that simulated operating conditions of the Thermal and Evolved Gas Analyzer (TEGA) that was onboard the 2007 Mars Phoenix Scout Mission [e.g., 2-8]. TEGA ovens operated at 12 mb pressure with a N2 carrier gas flowing at 0.04 sccm. Another key difference between SAM and TEGA is that TEGA was able to perform differential scanning calorimetry whereas SAM only has a pyrolysis oven. The operating conditions for TEGA and SAM have several key parameter differences including operating pressure (12 vs 30 mb), carrier gas (N2 vs. He), and carrier gas flow rate (0.04 vs 1 sccm). The objectives of this study are to characterize the thermal and evolved gas analysis of calcite under SAM operating conditions and then compare it to calcite thermal and evolved gas analysis under TEGA operating conditions.

  6. Quantitative analysis of the gas evolved from high polymers in γ-irradiation

    International Nuclear Information System (INIS)

    Arakawa, Kazuo; Hayakawa, Naohiro; Kuriyama, Isamu

    1977-09-01

    Polymers are used as insulator of cables in nuclear-reactor radiation field. To estimate the evolution of gases when irradiated, total gas yield and composition were measured for variety of polymers. Samples were irradiated at room temperature in vacuo with 60 Co-γ rays. For ethylene propylene rubber (EPR), irradiation in high-temperature steam was also made. Composition of the gas was determined with a mass spectrometer. G-value of the total gaseous product was 3.2 to 3.4 for low-density polyethylene (LDPE) and 2.5 to 2.7 for high-density polyethylene (HDPE). In both polyethylene, hydrogen gas predominated. When an anti-radiation oil was added to LDPE, gas evolution was reduced drastically. For chloro-sulfonated PE (Hypalon), SO 2 gas was one of the major products even when the polymer contained only about 1% of sulfonyl groups. G-value of the total gas for EPR irradiated in high-temperature steam was 3.1, regardless of the temperature. (auth.)

  7. Sulfur-Bearing Phases Detected by Evolved Gas Analysis of the Rocknest Aeolian Deposit, Gale Crater, Mars

    Science.gov (United States)

    Mcadam, Amy Catherine; Franz, Heather Bryant

    2014-01-01

    The Sample Analysis at Mars (SAM) instrument suite detected SO2, H2S, OCS, and CS2 from approx.450 to 800 C during evolved gas analysis (EGA) of materials from the Rocknest aeolian deposit in Gale Crater, Mars. This was the first detection of evolved sulfur species from a Martian surface sample during in situ EGA. SO2(approx. 3-22 micro-mol) is consistent with the thermal decomposition of Fe sulfates or Ca sulfites, or evolution/desorption from sulfur-bearing amorphous phases. Reactions between reduced sulfur phases such as sulfides and evolved O2 or H2O in the SAM oven are another candidate SO2 source. H2S (approx.41-109 nmol) is consistent with interactions of H2O, H2 and/or HCl with reduced sulfur phases and/or SO2 in the SAM oven. OCS (approx.1-5 nmol) and CS2(approx.0.2-1 nmol) are likely derived from reactions between carbon-bearing compounds and reduced sulfur. Sulfates and sulfites indicate some aqueous interactions, although not necessarily at the Rocknest site; Fe sulfates imply interaction with acid solutions whereas Ca sulfites can form from acidic to near-neutral solutions. Sulfides in the Rocknest materials suggest input from materials originally deposited in a reducing environment or from detrital sulfides from an igneous source. The presence of sulfides also suggests that the materials have not been extensively altered by oxidative aqueous weathering. The possibility of both reduced and oxidized sulfur compounds in the deposit indicates a nonequilibrium assemblage. Understanding the sulfur mineralogy in Rocknest materials, which exhibit chemical similarities to basaltic fines analyzed elsewhere on Mars, can provide insight in to the origin and alteration history of Martian surface materials.

  8. Insights into pyrolysis and co-pyrolysis of biomass and polystyrene: Thermochemical behaviors, kinetics and evolved gas analysis

    International Nuclear Information System (INIS)

    Özsin, Gamzenur; Pütün, Ayşe Eren

    2017-01-01

    Highlights: • TGA/MS/FT-IR was used to explore effect of polystyrene on pyrolytic decomposition of biomass. • The model-free iso-conversional methods were used for kinetic analysis. • Interactions occurred depending on the characteristics of the biomass. • TGA/MS and TGA/FT-IR coupling were used for gas analysis of co-pyrolysis for the first time. - Abstract: The purpose of this study was to investigate the effect on polystyrene (PS) during co-pyrolysis with biomass through thermal decomposition. The model-free iso-conversional methods (Kissinger, Friedman, Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, Starink and Vyazovkin) were adopted to calculate activation energy of the pyrolysis and co-pyrolysis process of two biomass samples (walnut shell: WS and peach stones: PST) with PS. It is found that biomass blending to PS decreased activation energy values and resulted in multi-step reaction mechanisms. Furthermore, changes in the evolution profiles of methyl, water, methoxy, carbon dioxide, benzene and styrene was monitored through evolved gas analysis via TGA/FT-IR and TGA/MS. Detection of temperature dependent release of volatiles indicated the differences occur as a result of compositional differences of biomass.

  9. Abundances of Volatile - Bearing Species from Evolved Gas Analysis of Samples from the Rocknest Aeolian Bedform in Gale Crater

    Science.gov (United States)

    Archer, P. D., Jr.; Franc, H. B.; Sutter, B.; McAdam, A.; Ming, D. W.; Morris, R. V.; Mahaffy, P. R.

    2013-01-01

    The Sample Analysis at Mars (SAM) instrument suite on board the Mars Science Laboratory (MSL) recently ran four samples from an aeolian bedform named Rocknest. SAM detected the evolution of H2O, CO2, O2, and SO2, indicative of the presence of multiple volatile bearing species (Fig 1). The Rocknest bedform is a windblown deposit selected as representative of both the windblown material in Gale crater as well as the globally-distributed martian dust. Four samples of Rocknest material were analyzed by SAM, all from the fifth scoop taken at this location. The material delivered to SAM passed through a 150 m sieve and is assumed to have been well mixed during the sample acquisition/preparation/handoff process. SAM heated the Rocknest samples to approx.835 C at a ramp rate of 35 C/min with a He carrier gas flow rate of apprx.1.5 standard cubic centimeters per minute and at an oven pressure of 30 mbar [1]. Evolved gases were detected by a quadrupole mass spectrometer (QMS). This abstract presents the molar abundances of H2O, CO2, O2, and SO2 as well as their concentration in rocknest samples using an estimated sample mass.

  10. Sulphur-bearing Compounds Detected by MSL SAM Evolved Gas Analysis of Materials from Yellowknife Bay, Gale Crater, Mars

    Science.gov (United States)

    McAdam, A. C.; Franz, H. B.; Archer, P. D. Jr.; Sutter, B.; Eigenbrode, J. L.; Freissinet, C.; Atreya, S. K.; Bish, D. L.; Blake, D. F.; Brunner, A.; hide

    2014-01-01

    The Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments on the Mars Science Laboratory (MSL) analysed several subsamples of sample fines (bearing phases present below the CheMin detection limit or difficult to characterize with XRD (e.g., X-ray amorphous phases). Here, we focus on potential constraints on phases that evolved SO2, H2S, OCS, and CS2 during thermal analysis.

  11. Abundances and implications of volatile-bearing species from evolved gas analysis of the Rocknest aeolian deposit, Gale Crater, Mars

    Science.gov (United States)

    Archer, Paul Douglas; Franz, Heather B.; Sutter, Brad; Arevalo, Ricardo D.; Coll, Patrice; Eigenbrode, Jennifer L.; Glavin, Daniel P.; Jones, John J.; Leshin, Laurie A.; Mahaffy, Paul R.; McAdam, Amy C.; McKay, Christopher P.; Ming, Douglas W.; Morris, Richard V.; Navarro-González, Rafael; Niles, Paul B.; Pavlov, Alex; Squyres, Steven W.; Stern, Jennifer C.; Steele, Andrew; Wray, James J.

    2014-01-01

    The Sample Analysis at Mars (SAM) instrument on the Mars Science Laboratory (MSL) rover Curiosity detected evolved gases during thermal analysis of soil samples from the Rocknest aeolian deposit in Gale Crater. Major species detected (in order of decreasing molar abundance) were H2O, SO2, CO2, and O2, all at the µmol level, with HCl, H2S, NH3, NO, and HCN present at the tens to hundreds of nmol level. We compute weight % numbers for the major gases evolved by assuming a likely source and calculate abundances between 0.5 and 3 wt.%. The evolution of these gases implies the presence of both oxidized (perchlorates) and reduced (sulfides or H-bearing) species as well as minerals formed under alkaline (carbonates) and possibly acidic (sulfates) conditions. Possible source phases in the Rocknest material are hydrated amorphous material, minor clay minerals, and hydrated perchlorate salts (all potential H2O sources), carbonates (CO2), perchlorates (O2 and HCl), and potential N-bearing materials (e.g., Martian nitrates, terrestrial or Martian nitrogenated organics, ammonium salts) that evolve NH3, NO, and/or HCN. We conclude that Rocknest materials are a physical mixture in chemical disequilibrium, consistent with aeolian mixing, and that although weathering is not extensive, it may be ongoing even under current Martian surface conditions.

  12. Kinetics and evolved gas analysis for pyrolysis of food processing wastes using TGA/MS/FT-IR.

    Science.gov (United States)

    Özsin, Gamzenur; Pütün, Ayşe Eren

    2017-06-01

    The objective of this study was to identify the pyrolysis of different bio-waste produced by food processing industry in a comprehensible manner. For this purpose, pyrolysis behaviors of chestnut shells (CNS), cherry stones (CS) and grape seeds (GS) were investigated by thermogravimetric analysis (TGA) combined with a Fourier-transform infrared (FT-IR) spectrometer and a mass spectrometer (MS). In order to make available theoretical groundwork for biomass pyrolysis, activation energies were calculated with the help of four different model-free kinetic methods. The results are attributed to the complex reaction schemes which imply parallel, competitive and complex reactions during pyrolysis. During pyrolysis, the evolution of volatiles was also characterized by FT-IR and MS. The main evolved gases were determined as H 2 O, CO 2 and hydrocarbons such as CH 4 and temperature dependent profiles of the species were obtained. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Evolved Gas Measurements Planned for the Lower Layers of the Gale Crater Mound with the Sample Analysis at Mars Instrument Suite

    Science.gov (United States)

    Mahaffy, P. R.; Franz, H.; McAdam, A.; Conrad, P. G.; Brunner, A.; Cabane, M.; Webster, C. R.

    2011-12-01

    The lower mound strata of Gale Crater provide a diverse set of chemical environments for exploration by the varied tools of the Curiosity Rover of the Mars Science Laboratory (MSL) Mission. Orbital imaging and spectroscopy clearly reveal distinct layers of hydrated minerals, sulfates, and clays with abundant evidence of a variety of fluvial processes. The three instruments of the MSL Sample Analysis at Mars (SAM) investigation, the Quadrupole Mass Spectrometer (QMS), the Tunable Laser Spectrometer (TLS), and the Gas Chromatograph (GC) are designed to analyze either atmospheric gases or volatiles thermally evolved or chemically extracted from powdered rock or soil. The presence or absence of organic compounds in these layers is of great interest since such an in situ search for this type of record has not been successfully implemented since the mid-70s Viking GCMS experiments. However, regardless of the outcome of the analysis for organics, the abundance and isotopic composition of thermally evolved inorganic compounds should also provide a rich data set to complement the mineralogical and elemental information provided by other MSL instruments. In addition, these evolved gas analysis (EGA) experiments will help test sedimentary models proposed by Malin and Edgett (2000) and then further developed by Milliken et al (2010) for Gale Crater. In the SAM EGA experiments the evolution temperatures of H2O, CO2, SO2, O2, or other simple compounds as the samples are heated in a helium stream to 1000C provides information on mineral types and their associations. The isotopic composition of O, H, C, and S can be precisely determined in several evolved compounds and compared with the present day atmosphere. Such SAM results might be able to test mineralogical evidence of changing sedimentary and alteration processes over an extended period of time. For example, Bibring et al (2006) have suggested such a major shift from early nonacidic to later acidic alteration. We will

  14. Evolved Gas Measurements Planned for the Lower Layers of the Gale Crater Mound with the Sample Analysis at Mars Instrument Suite

    Science.gov (United States)

    Mahaffy, Paul; Brunner, Anna; McAdam, Amy; Franz, Heather; Conrad, Pamela; Webster, Chris; Cabane, Michel

    2009-01-01

    The lower mound strata of Gale Crater provide a diverse set of chemical environments for exploration by the varied tools of the Curiosity Rover of the Mars Science Laboratory (MSL) Mission. Orbital imaging and spectroscopy clearly reveal distinct layers of hydrated minerals, sulfates, and clays with abundant evidence of a variety of fluvial processes. The three instruments of the MSL Sample Analysis at aMars (SAM) investigation, the Quadrupole Mass Spectrometer (QMS), the Tunable Laser Spectrometer (TLS), and the Gas Chromatograph (GC) are designed to analyze either atmospheric gases or volatiles thermally evolved or chemically extracted from powdered rock or soil. The presence or absence of organic compounds in these layers is of great interest since such an in situ search for this type of record has not been successfully implemented since the mid-60s Viking GCMS experiments. However, regardless of the outcome of the analysis for organics, the abundance and isotopic composition of thermally evolved inorganic compounds should also provide a rich data set to complement the mineralogical and elemental information provided by other MSL instruments. In addition, these evolved gas analysis (EGA) experiments will help test sedimentary models proposed by Malin and Edgett (2000) and then further developed by Milliken et al (2010) for Gale Crater. In the SAM EGA experiments the evolution temperatures of H2O, CO2, SO2, O2, or other simple compounds as the samples are heated in a helium stream to 1000 C provides information on mineral types and their associations. The isotopic composition of O, H, C, and S can be precisely determined in several evolved compounds and compared with the present day atmosphere. Such SAM results might be able to test mineralogical evidence of changing sedimentary and alteration processes over an extended period of time. For example, Bibring et al (2006) have suggested such a major shift from early nonacidic to later acidic alteration. We will

  15. Nanophase Carbonates on Mars: Does Evolved Gas Analysis of Nanophase Carbonates Reveal a Large Organic Carbon Budget in Near-surface Martian Materials?

    Science.gov (United States)

    Archer, P. D., Jr.; Ming, D. W.; Sutter, B.; Niles, P. B.; Eigenbrode, J. L.

    2015-12-01

    Evolved Gas Analysis (EGA), which involves heating a sample and monitoring the gases released, has been performed on Mars by the Viking gas chromatography/mass spectrometry instruments, the Thermal and Evolved Gas Analyzer (TEGA) on the Phoenix lander, and the Sample Analysis at Mars (SAM) instrument on the Mars Science Laboratory. All of these instruments detected CO2 released during sample analysis at abundances of ~0.1 to 5 wt% assuming a carbonate source. The source of the CO2 can be constrained by evaluating the temperature of the gas release, a capability of both the TEGA and SAM instruments. The samples analyzed by SAM show that the majority of the CO2is released below 400 °C, much lower than traditional carbonate decomposition temperatures which can be as low as 400 °C for some siderites, with magnesites and calcites decomposing at even higher temperatures. In addition to mineralogy, decomposition temperature can depend on particle size (among other factors). If carbonates formed on Mars under low temperature and relative humidity conditions, the resulting small particle size (nanophase) carbonates could have low decomposition temperatures. We have found that calcite can be synthesized by exposing CaO to water vapor and CO2 and that the resulting mineral has an EGA peak of ~550 °C for CO2, which is about 200 °C lower than for other calcites. Work is ongoing to produce Fe and Mg-bearing carbonates using the same process. Current results suggest that nanophase calcium carbonates cannot explain the CO2 released from martian samples. If the decomposition temperatures of Mg and Fe-bearing nanophase carbonates are not significantly lower than 400 °C, other candidate sources include oxalates and carboxylated organic molecules. If present, the abundance of organic carbon in these samples could be > 0.1 wt % (1000s of ppm), a signficant departure from the paradigm of the organic-poor Mars based on Viking results.

  16. Evolved Gas Analysis of Mars Analog Samples from the Arctic Mars Analog Svalbard Expedition: Implications for Analyses by the Mars Science Laboratory

    Science.gov (United States)

    McAdam, A.; Stern, J. C.; Mahaffy, P. R.; Blake, D. F.; Bristow, T.; Steele, A.; Amundsen, H. E. F.

    2012-01-01

    The 2011 Arctic Mars Analog Svalbard Expedition (AMASE) investigated several geologic settings on Svalbard, using methodologies and techniques being developed or considered for future Mars missions, such as the Mars Science Laboratory (MSL). The Sample Analysis at Mars (SAM) instrument suite on MSL consists of a quadrupole mass spectrometer (QMS), a gas chromatograph (GC), and a tunable laser spectrometer (TLS), which analyze gases created by pyrolysis of samples. During AMASE, a Hiden Evolved Gas Analysis-Mass Spectrometer (EGA-MS) system represented the EGA-QMS capability of SAM. Another MSL instrument, CheMin, will use x-ray diffraction (XRD) and x-ray fluorescence (XRF) to perform quantitative mineralogical characterization of samples. Field-portable versions of CheMin were used during AMASE. AMASE 2011 sites spanned a range of environments relevant to understanding martian surface materials, processes and habitability. They included the basaltic Sverrefjell volcano, which hosts carbonate globules, cements and coatings, carbonate and sulfate units at Colletth0gda, Devonian sandstone redbeds in Bockfjorden, altered basaltic lava delta deposits at Mt. Scott Keltie, and altered dolerites and volcanics at Botniahalvoya. Here we focus on SAM-like EGA-MS of a subset of the samples, with mineralogy comparisons to CheMin team results. The results allow insight into sample organic content as well as some constraints on sample mineralogy.

  17. Kinetics of Cold-Cap Reactions for Vitrification of Nuclear Waste Glass Based on Simultaneous Differential Scanning Calorimetry - Thermogravimetry (DSC-TGA) and Evolved Gas Analysis (EGA)

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Carmen P.; Pierce, David A.; Schweiger, Michael J.; Kruger, Albert A.; Chun, Jaehun; Hrma, Pavel R.

    2013-12-03

    For vitrifying nuclear waste glass, the feed, a mixture of waste with glass-forming and modifying additives, is charged onto the cold cap that covers 90-100% of the melt surface. The cold cap consists of a layer of reacting molten glass floating on the surface of the melt in an all-electric, continuous glass melter. As the feed moves through the cold cap, it undergoes chemical reactions and phase transitions through which it is converted to molten glass that moves from the cold cap into the melt pool. The process involves a series of reactions that generate multiple gases and subsequent mass loss and foaming significantly influence the mass and heat transfers. The rate of glass melting, which is greatly influenced by mass and heat transfers, affects the vitrification process and the efficiency of the immobilization of nuclear waste. We studied the cold-cap reactions of a representative waste glass feed using both the simultaneous differential scanning calorimetry thermogravimetry (DSC-TGA) and the thermogravimetry coupled with gas chromatography-mass spectrometer (TGA-GC-MS) as complementary tools to perform evolved gas analysis (EGA). Analyses from DSC-TGA and EGA on the cold-cap reactions provide a key element for the development of an advanced cold-cap model. It also helps to formulate melter feeds for higher production rate.

  18. Field Characterization of the Mineralogy and Organic Chemistry of Carbonates from the 2010 Arctic Mars Analog Svalbard Expedition by Evolved Gas Analysis

    Science.gov (United States)

    McAdam, A. C.; Ten Kate, I. L.; Stern, J. C.; Mahaffy, P. R.; Blake, D. F.; Morris, R. V.; Steele, A.; Amundson, H. E. F.

    2011-01-01

    The 2010 Arctic Mars Analog Svalbard Expedition (AMASE) investigated two geologic settings using methodologies and techniques being developed or considered for future Mars missions, such as the Mars Science Laboratory (MSL), ExoMars, and Mars Sample Return. The Sample Analysis at Mars (SAM) [1] instrument suite, which will be on MSL, consists of a quadrupole mass spectrometer (QMS), a gas chromatograph (GC), and a tunable laser mass spectrometer (TLS); all will be applied to analyze gases created by pyrolysis of samples. During AMASE, a Hiden Evolved Gas Analysis-Mass Spectrometer (EGA-MS) system represented the EGA-MS capability of SAM. Another MSL instrument, CheMin, will use x-ray diffraction (XRD) and x-ray fluorescence (XRF) to perform quantitative mineralogical characterization of samples [e.g., 2]. Field-portable versions of CheMin were used during AMASE. AMASE 2010 focused on two sites that represented biotic and abiotic analogs. The abiotic site was the basaltic Sigurdfjell vent complex, which contains Mars-analog carbonate cements including carbonate globules which are excellent analogs for the globules in the ALH84001 martian meteorite [e.g., 3, 4]. The biotic site was the Knorringfjell fossil methane seep, which featured carbonates precipitated in a methane-supported chemosynthetic community [5]. This contribution focuses on EGA-MS analyses of samples from each site, with mineralogy comparisons to CheMin team results. The results give insight into organic content and organic-mineral associations, as well as some constraints on the minerals present.

  19. Behaviour of and mass transfer at gas-evolving electrodes

    NARCIS (Netherlands)

    Janssen, L.J.J.

    1989-01-01

    A completes set of models for the mass transfer of indicator ions to gas-evolving electrodes with different behaviour of bubbles is described theoretically. Sliding bubbles, rising detached single bubbles, jumping detached coalescence bubbles and ensembles of these types of bubbles are taken into

  20. Clustering impact regime with shocks in freely evolving granular gas

    Science.gov (United States)

    Isobe, Masaharu

    2017-06-01

    A freely cooling granular gas without any external force evolves from the initial homogeneous state to the inhomogeneous clustering state, at which the energy decay deviates from the Haff's law. The asymptotic behavior of energy in the inelastic hard sphere model have been predicted by several theories, which are based on the mode coupling theory or extension of inelastic hard rods gas. In this study, we revisited the clustering regime of freely evolving granular gas via large-scale molecular dynamics simulation with up to 16.7 million inelastic hard disks. We found novel regime regarding on collisions between "clusters" spontaneously appearing after clustering regime, which can only be identified more than a few million particles system. The volumetric dilatation pattern of semicircular shape originated from density shock propagation are well characterized on the appearing of "cluster impact" during the aggregation process of clusters.

  1. EVOLVE

    CERN Document Server

    Deutz, André; Schütze, Oliver; Legrand, Pierrick; Tantar, Emilia; Tantar, Alexandru-Adrian

    2017-01-01

    This book comprises nine selected works on numerical and computational methods for solving multiobjective optimization, game theory, and machine learning problems. It provides extended versions of selected papers from various fields of science such as computer science, mathematics and engineering that were presented at EVOLVE 2013 held in July 2013 at Leiden University in the Netherlands. The internationally peer-reviewed papers include original work on important topics in both theory and applications, such as the role of diversity in optimization, statistical approaches to combinatorial optimization, computational game theory, and cell mapping techniques for numerical landscape exploration. Applications focus on aspects including robustness, handling multiple objectives, and complex search spaces in engineering design and computational biology.

  2. Market opening: how will European gas supply evolve?

    International Nuclear Information System (INIS)

    Delon, Ch.

    1999-01-01

    With the implementation of the gas directive, European gas companies are facing many new challenges. Some concern the upstream gas sector in particular, notably with the new rules of competition in Europe, the changes in the structure of gas industries and their adaptation to the new Europe-wide market. For this first round table to the 116. gas conference, chaired by Sophie Mayeux, journalist and editor of the Est Eco journal, four representatives of major European companies and one representative of the banking sector examined the possible future scenarios for gas supply in Europe. (authors)

  3. Evolving markets and new end use gas technologies

    International Nuclear Information System (INIS)

    Overall, J.

    1995-01-01

    End use gas technologies, and products for residential, commercial, and industrial uses were reviewed, and markets and market drivers needed for end use technologies in the different types of markets were summarized. The range of end use technologies included: gas fireplaces, combination heating/water heating systems, integrated appliance such as heating/ventilation units, gas cooling, and space cooling for commercial markets. The present and future status of each product market was discussed. Growing markets such as cogeneration, and gas turbine technology also received attention, along with regulatory and environmental concerns. The need to be knowledgeable about current market drivers and to introduce new ones, and the evolution of technology were emphasized as means by which the industry will continue to be able to exert a decisive influence on the direction of these markets

  4. What constitutes the gas sales contract in the evolving marketplace?

    International Nuclear Information System (INIS)

    Hughes, T.M.

    1996-01-01

    A general overview of certain fundamental issues of contract law, which are relevant to gas sales transactions, was presented. Since deregulation, parties of the Canadian natural gas market are free to negotiate the terms of arrangements and contracts with any number of buyers and sellers. With deregulation also came a substantial increase in the amount of litigation regarding sales contracts. Two basic issues that should be kept in mind when negotiating any gas sales contract were letter agreements, (two versions of non-binding letters of intent), and requirement of writing. Within the requirements of writing one should be mindful of the legal implications of the fraud statutes, the Sale of Goods Act, what constitutes a sufficient note or memorandum, what constitutes the requisite signature, contracting out of the requirement of writing and signature on the mass agreement, certainty of terms, and the terms implied by legislation. It was considered advantageous for both buyers and sellers to continue to be vigilant about the contractual arrangements respecting all of their gas transactions

  5. The Evolving Role of LNG in the Gas Market

    Energy Technology Data Exchange (ETDEWEB)

    De Jong, D.; Van der Linde, C.; Smeenk, T.

    2010-09-15

    The global energy scene is changing rapidly. Producing countries are tightening their grip on the development of their resources, emerging (and other) economies are taking a direct political interest in securing supplies, politics and business are increasingly integrated in international energy deals, and energy is on the political agenda of every government. Compounding this, prices of energy skyrocketed over the four years leading up to August 2008. As a result more gas resources became economical to develop, creating more supply potential than before. However, the severe crisis in international financial markets and national banking systems is now changing this outlook. Prices have come down, and this, combined with the current decline in economic activity, is likely to affect the timing of investment decisions on new pipeline and liquefied natural gas (LNG) projects. The impact on national economies on energy demand, and on the relative position of gas in the energy market could be considerable. At the same time, some consuming countries are also reviewing the environmental effect of their energy policies and the security of their energy supply. Any change in these policies could affect the place of gas in the energy mix. These developments are still unfolding; it is difficult to say at this stage in what ways and to what extent the position of natural gas will change. Nevertheless, some expect further globalization of the gas business, with different market structures, more fragmented value chains, more flexibility in supplies to markets, and shorter term contracts. In this respect, LNG is regarded as the major potential game changer. Indeed the LNG business model has been changing over recent years into one of greater flexibility, promising producers higher rewards, albeit in return for higher risks. More recently the perspective of high rewards in a market hungry for supplies has changed radically, at least for the next few years. A global crisis, lower oil

  6. The Evolving Role of LNG in the Gas Market

    International Nuclear Information System (INIS)

    De Jong, D.; Van der Linde, C.; Smeenk, T.

    2010-01-01

    The global energy scene is changing rapidly. Producing countries are tightening their grip on the development of their resources, emerging (and other) economies are taking a direct political interest in securing supplies, politics and business are increasingly integrated in international energy deals, and energy is on the political agenda of every government. Compounding this, prices of energy skyrocketed over the four years leading up to August 2008. As a result more gas resources became economical to develop, creating more supply potential than before. However, the severe crisis in international financial markets and national banking systems is now changing this outlook. Prices have come down, and this, combined with the current decline in economic activity, is likely to affect the timing of investment decisions on new pipeline and liquefied natural gas (LNG) projects. The impact on national economies on energy demand, and on the relative position of gas in the energy market could be considerable. At the same time, some consuming countries are also reviewing the environmental effect of their energy policies and the security of their energy supply. Any change in these policies could affect the place of gas in the energy mix. These developments are still unfolding; it is difficult to say at this stage in what ways and to what extent the position of natural gas will change. Nevertheless, some expect further globalization of the gas business, with different market structures, more fragmented value chains, more flexibility in supplies to markets, and shorter term contracts. In this respect, LNG is regarded as the major potential game changer. Indeed the LNG business model has been changing over recent years into one of greater flexibility, promising producers higher rewards, albeit in return for higher risks. More recently the perspective of high rewards in a market hungry for supplies has changed radically, at least for the next few years. A global crisis, lower oil

  7. Thermogravimetry-evolved gas analysis–mass spectrometry system ...

    Indian Academy of Sciences (India)

    Unknown

    Thermal analysis is a widely used analytical technique for materials research. ... nique. This method can not distinguish the actual nature ... Among the different types of mass .... pressure and (iv) for qualitative and quantitative analysis.

  8. Qualitative Functional Decomposition Analysis of Evolved Neuromorphic Flight Controllers

    Directory of Open Access Journals (Sweden)

    Sanjay K. Boddhu

    2012-01-01

    Full Text Available In the previous work, it was demonstrated that one can effectively employ CTRNN-EH (a neuromorphic variant of EH method methodology to evolve neuromorphic flight controllers for a flapping wing robot. This paper describes a novel frequency grouping-based analysis technique, developed to qualitatively decompose the evolved controllers into explainable functional control blocks. A summary of the previous work related to evolving flight controllers for two categories of the controller types, called autonomous and nonautonomous controllers, is provided, and the applicability of the newly developed decomposition analysis for both controller categories is demonstrated. Further, the paper concludes with appropriate discussion of ongoing work and implications for possible future work related to employing the CTRNN-EH methodology and the decomposition analysis techniques presented in this paper.

  9. Impact of the spatial distribution of morphological pattern on the efficiency of electrocatalytic gas evolving reactions

    Directory of Open Access Journals (Sweden)

    Žerađanin Aleksandar R.

    2014-01-01

    Full Text Available The efficiency of electrocatalytic gas evolving reactions (hydrogen, chlorine and oxygen evolution is a key challenge for the important industrial processes, such as chlor-alkali electrolysis or water electrolysis. Central issue for the aforementioned electrocatalytic processes is huge power consumption. Experimental results accumulated in the past, as well as some predictive models ("volcano" plots indicate that altering the nature of the electrode material cannot significantly increase the activity of mentioned reactions. Consequently, it is necessary to find a qualitatively different strategy for improving the energy efficiency of electrocatalytic gas evolving reactions. Usually disregarded fact is that the gas evolution is an oscillatory phenomenon. Given the oscillatory behavior, a key parameter of macrokinetics of gas electrode is the frequency of gas-bubble detachment. Bearing in mind that the gas evolution greatly depends on the surface morphology, a methodology is proposed that establishes a rational link between the morphological pattern of electrode with electrode activity and stability. Characterization was performed using advanced analytical tools. Frequency of gas-bubble detachment is obtained in the configuration of scanning electrochemical microscopy (SECM while the corrosion stability is analyzed using miniaturized scanning flow electrochemical cell connected to the mass spectrometer (SFC-ICPMS.

  10. AlintaGas perspective on evolving competition in the Western Australian energy market

    International Nuclear Information System (INIS)

    Harvey, Ph.

    1999-01-01

    The author discusses the evolving competition in the Western Australian energy market, with a clear focus on gas. Before considering the future energy market, he puts today's market in perspective and set the framework within which the development of the future markets should be considered. What is a competitive market? It is a market where there are enough producers and enough users for competition between them to determine prices, which are set prices, not costs. An example of a competitive gas market in Western Australia is the Pilbara. There are enough producers and enough users in the Pilbara area that gas prices are set by the normal forces of supply and demand and transport costs are essentially negligible. There is no need for regulation or any external price setting - the forces of supply and demand determine prices. In the south west gas market there are the same gas suppliers, but a different and larger group of customers. This market differs from the Pilbara market because now there are transport costs involved. The transport element is a natural monopoly - and it is important to ensure transport prices do not distort the competitive market established between producers and users. Hence, third party access to the Dampier to Bunbury Natural Gas Pipeline (DBNGP), under properly regulated access arrangements to ensure there is no market distortion, allows the forces of competition to set prices in the south west gas market. Western Australia is fortunate - and unique among the Australian states - in that it has a number of gas producers keen to sell into Western Australian gas markets. Hence, gas on gas competition - as well as inter-fuel competition - is setting prices. For historic reasons - and they are good reasons - energy markets in Western Australia are not yet completely open. There is however a program of market deregulation that commenced on I January 1995 and will be completed on July 2002, which means that all gas customers, even residential

  11. On-line gas chromatographic analysis of airborne particles

    Science.gov (United States)

    Hering, Susanne V [Berkeley, CA; Goldstein, Allen H [Orinda, CA

    2012-01-03

    A method and apparatus for the in-situ, chemical analysis of an aerosol. The method may include the steps of: collecting an aerosol; thermally desorbing the aerosol into a carrier gas to provide desorbed aerosol material; transporting the desorbed aerosol material onto the head of a gas chromatography column; analyzing the aerosol material using a gas chromatograph, and quantizing the aerosol material as it evolves from the gas chromatography column. The apparatus includes a collection and thermal desorption cell, a gas chromatograph including a gas chromatography column, heated transport lines coupling the cell and the column; and a quantization detector for aerosol material evolving from the gas chromatography column.

  12. Treatment of off-gas evolved from thermal decomposition of sludge waste

    International Nuclear Information System (INIS)

    Doo-Seong Hwang; Yun-Dong Choi; Gyeong-Hwan Jeong; Jei-Kwon Moon

    2013-01-01

    Korea Atomic Energy Research Institute (KAERI) started a decommissioning program of a uranium conversion plant. The treatment of the sludge waste, which was generated during the operation of the plant, is one of the most important tasks in the decommissioning program of the plant. The major compounds of sludge waste are nitrate salts and uranium. The sludge waste is denitrated by thermal decomposition. The treatment of off-gas evolved from the thermal decomposition of nitrate salts in the sludge waste is investigated. The nitrate salts in the sludge were decomposed in two steps: the first decomposition is due to the ammonium nitrate, and the second is due to the sodium and calcium nitrate and calcium carbonate. The components of off-gas from the decomposition of ammonium nitrate at low temperature are NH 3 , N 2 O, NO 2 , and NO. In addition, the components from the decomposition of sodium and calcium nitrate at high temperature are NO 2 and NO. Off-gas from the thermal decomposition is treated by the catalytic oxidation of ammonia and selective catalytic reduction (SCR). Ammonia is converted into nitrogen oxides through the oxidation catalyst and all nitrogen oxides are removed by SCR treatment besides nitrous oxide, which is greenhouse gas. An additional process is needed to remove nitrous oxide, and the feeding rate of ammonia in SCR should be controlled properly for evolved nitrogen oxides. (author)

  13. The actual current density of gas-evolving electrodes—Notes on the bubble coverage

    International Nuclear Information System (INIS)

    Vogt, H.

    2012-01-01

    All investigations of electrochemical reactors with gas-evolving electrodes must take account of the fact that the actual current density controlling cell operation commonly differs substantially from the nominal current density used for practical purposes. Both quantities are interrelated by the fractional bubble coverage. This parameter is shown to be affected by a large number of operational quantities. However, available relationships of the bubble coverage take account only of the nominal current density. A further essential insufficiency is their inconsistency with reality for very large values of the bubble coverage being of relevance for operation conditions leading to anode effects. An improved relationship applicable to the total range is proposed.

  14. Network Analysis of Earth's Co-Evolving Geosphere and Biosphere

    Science.gov (United States)

    Hazen, R. M.; Eleish, A.; Liu, C.; Morrison, S. M.; Meyer, M.; Consortium, K. D.

    2017-12-01

    A fundamental goal of Earth science is the deep understanding of Earth's dynamic, co-evolving geosphere and biosphere through deep time. Network analysis of geo- and bio- `big data' provides an interactive, quantitative, and predictive visualization framework to explore complex and otherwise hidden high-dimension features of diversity, distribution, and change in the evolution of Earth's geochemistry, mineralogy, paleobiology, and biochemistry [1]. Networks also facilitate quantitative comparison of different geological time periods, tectonic settings, and geographical regions, as well as different planets and moons, through network metrics, including density, centralization, diameter, and transitivity.We render networks by employing data related to geographical, paragenetic, environmental, or structural relationships among minerals, fossils, proteins, and microbial taxa. An important recent finding is that the topography of many networks reflects parameters not explicitly incorporated in constructing the network. For example, networks for minerals, fossils, and protein structures reveal embedded qualitative time axes, with additional network geometries possibly related to extinction and/or other punctuation events (see Figure). Other axes related to chemical activities and volatile fugacities, as well as pressure and/or depth of formation, may also emerge from network analysis. These patterns provide new insights into the way planets evolve, especially Earth's co-evolving geosphere and biosphere. 1. Morrison, S.M. et al. (2017) Network analysis of mineralogical systems. American Mineralogist 102, in press. Figure Caption: A network of Phanerozoic Era fossil animals from the past 540 million years includes blue, red, and black circles (nodes) representing family-level taxa and grey lines (links) between coexisting families. Age information was not used in the construction of this network; nevertheless an intrinsic timeline is embedded in the network topology. In

  15. A Change Impact Analysis to Characterize Evolving Program Behaviors

    Science.gov (United States)

    Rungta, Neha Shyam; Person, Suzette; Branchaud, Joshua

    2012-01-01

    Change impact analysis techniques estimate the potential effects of changes made to software. Directed Incremental Symbolic Execution (DiSE) is an intraprocedural technique for characterizing the impact of software changes on program behaviors. DiSE first estimates the impact of the changes on the source code using program slicing techniques, and then uses the impact sets to guide symbolic execution to generate path conditions that characterize impacted program behaviors. DiSE, however, cannot reason about the flow of impact between methods and will fail to generate path conditions for certain impacted program behaviors. In this work, we present iDiSE, an extension to DiSE that performs an interprocedural analysis. iDiSE combines static and dynamic calling context information to efficiently generate impacted program behaviors across calling contexts. Information about impacted program behaviors is useful for testing, verification, and debugging of evolving programs. We present a case-study of our implementation of the iDiSE algorithm to demonstrate its efficiency at computing impacted program behaviors. Traditional notions of coverage are insufficient for characterizing the testing efforts used to validate evolving program behaviors because they do not take into account the impact of changes to the code. In this work we present novel definitions of impacted coverage metrics that are useful for evaluating the testing effort required to test evolving programs. We then describe how the notions of impacted coverage can be used to configure techniques such as DiSE and iDiSE in order to support regression testing related tasks. We also discuss how DiSE and iDiSE can be configured for debugging finding the root cause of errors introduced by changes made to the code. In our empirical evaluation we demonstrate that the configurations of DiSE and iDiSE can be used to support various software maintenance tasks

  16. Removal of Contaminants from Waste Streams at Gas Evolving Flow-Through Porous Electrodes

    International Nuclear Information System (INIS)

    Mahmoud Saleh, M.

    1999-01-01

    Electrochemical techniques have been used for the removal of inorganic and organic toxic materials from industrial waste streams. One of the most important branch of these electrochemical techniques is the flow-through porous electrode. Such systems allow for the continuous operation and hence continuous removal of the contaminants from waste streams at high rates and high efficiency. However, when there is an evolution of gas bubbles with the removal process, the treatment process needs a much different treatment of both the design and the mathematical treatment of the such these systems. The evolving gas bubbles within the electrode decrease the pore electrolyte conductivity of the porous electrodes, decrease the efficiency and make the current more non-uniform. This cause the under utilization of the reaction area and finally make the electrode inoperable. In this work the harmful effects of the gas bubbles on the performance of the porous electrode will be modeled. The model accounts for the effects of kinetic, mass transfer and gas bubbles resistance on the overall performance of the electrode. This will help in optimizing the operating conditions and the cell design

  17. Hanford gas dispersion analysis

    International Nuclear Information System (INIS)

    Fujita, R.K.; Travis, J.R.

    1994-01-01

    An analysis was performed to verify the design of a waste gas exhauster for use in support of rotary core sampling activities at the Westinghouse Hanford Waste Tank Farm. The exhauster was designed to remove waste gases from waste storage tanks during the rotary core drilling process of the solid materials in the tank. Some of the waste gases potentially are very hazardous and must be monitored during the exhauster's operation. If the toxic gas concentrations in specific areas near the exhauster exceed minimum Threshold Limit Values (TLVs), personnel must be excluded from the area. The exhauster stack height is of interest because an increase in stack height will alter the gas concentrations at the critical locations. The exhaust stack is currently ∼4.6 m (15 ft) high. An equipment operator will be located within a 6.1 m (20 ft) radius of the exhaust stack, and his/her head will be at an elevation 3.7 m (12 ft) above ground level (AGL). Therefore, the maximum exhaust gas concentrations at this location must be below the TLV for the toxic gases. Also, the gas concentrations must be within the TLV at a 61 m (200 ft) radius from the stack. If the calculated gas concentrations are above the TLV, where the operator is working below the stack at the 61 m (200 ft) radius location, the stack height may need to be increased

  18. Evolving natural gas markets: LNG possibilities for a hydrothermal power system

    Energy Technology Data Exchange (ETDEWEB)

    Correia, Tiago B.; Resende, Joao P.; Costa, Agnes M. [Brazilian Ministry of Mines and Energy, Brasilia, DF (Brazil)

    2008-07-01

    The latest advancements in the natural gas - NG industry have brought new opportunities for the resource's application, especially in the power industry. On the one hand, rapid growth in demand and falling costs of transportation over long distances, particularly as liquefied natural gas - LNG, should lead to a more integrated NG world market. On the other, the deregulation of electricity markets and the growth of independent power producers - IPPs using NG as a fuel for generating peak load power have increased the demand for more flexible NG supply contracts. These factors have allowed a shift in the timing of investment and contract negotiation in NG market. Traditionally, firms searched for trading partners and signed long-term contracts before investing in infrastructure. In the evolving LNG market, producers invest in infrastructure before they have buyers for all their expected outputs, while buyers undertake investment before having firm contracts for all their expected NG needs. These technological and market changes may foster greater participation of a fully flexible NG power plants in the Brazilian electricity market. Nowadays, thermal power long-term capacity contracts customized and negotiated in the local electricity pool (ACR) require power producer to award guarantees of NG firm supply, substantially increasing their cost. A combination of flexible LNG supply contracts and electricity pool contracts may present a solution to the lack of competitiveness of NG power plants in the Brazilian power industry. (author)

  19. Thermal and Evolved Gas Behavior of Calcite Under Mars Phoenix TEGA Operating Conditions

    Science.gov (United States)

    Ming, D.W.; Niles, P.B.; Morris, R.V.; Boynton, W.V.; Golden, D.C.; Lauer, H.V.; Sutter, B.

    2009-01-01

    The Mars Phoenix Scout Mission with its diverse instrument suite successfully examined several soils on the Northern plains of Mars. The Thermal and Evolved Gas Analyzer (TEGA) was employed to detect organic and inorganic materials by coupling a differential scanning calorimeter (DSC) with a magnetic-sector mass spectrometer (MS). Martian soil was heated up to 1000 C in the DSC ovens and evolved gases from mineral decomposition products were examined with the MS. TEGA s DSC has the capability to detect endothermic and exothermic reactions during heating that are characteristic of minerals present in the Martian soil. Initial TEGA results indicated the presence of endothermic peaks with onset temperatures that ranged from 675 C to 750 C with corresponding CO2 release. This result suggests the presence of calcite (CaCO3. CaO + CO2). Organic combustion to CO2 is not likely since this mostly occurs at temperatures below 550 C. Fe-carbonate and Mg-carbonate are not likely because their decomposition temperatures are less than 600 C. TEGA enthalpy determinations suggest that calcite, may occur in the Martian soil in concentrations of approx.1 to 5 wt. %. The detection of calcite could be questioned based on previous results that suggest Mars soils are mostly acidic. However, the Phoenix landing site soil pH was measured at pH 8.3 0.5, which is typical of terrestrial soils where pH is controlled by calcite solubility. The range of onset temperatures and calcite concentration as calculated by TEGA is poorly con-strained in part because of limited thermal data of cal-cite at reduced pressures. TEGA operates at calcite literature thermal data was obtained at 1000 mbar or higher pressures.

  20. GALAXY FORMATION WITH COLD GAS ACCRETION AND EVOLVING STELLAR INITIAL MASS FUNCTION

    International Nuclear Information System (INIS)

    Kang Xi; Lin, W. P.; Skibba, Ramin; Chen, D. N.

    2010-01-01

    The evolution of the galaxy stellar mass function is especially useful to test the current model of galaxy formation. Observational data have revealed a few inconsistencies with predictions from the ΛCDM model. For example, most massive galaxies have already been observed at very high redshifts, and they have experienced only mild evolution since then. In conflict with this, semi-analytical models (SAMs) of galaxy formation predict an insufficient number of massive galaxies at high redshift and a rapid evolution between redshift 1 and 0. In addition, there is a strong correlation between star formation rate (SFR) and stellar mass for star-forming galaxies, which can be roughly reproduced with the model, but with a normalization that is too low at high redshift. Furthermore, the stellar mass density obtained from the integral of the cosmic star formation history is higher than the measured one by a factor of 2. In this paper, we study these issues using an SAM that includes (1) cold gas accretion in massive halos at high redshift; (2) tidal stripping of stellar mass from satellite galaxies; and (3) an evolving stellar initial mass function (IMF; bottom-light) with a higher gas recycle fraction. Our results show that the combined effects from (1) and (2) can predict sufficiently massive galaxies at high redshifts and reproduce their mild evolution at low redshift, while the combined effects of (1) and (3) can reproduce the correlation between SFR and stellar mass for star-forming galaxies across a wide range of redshifts. A bottom-light/top-heavy stellar IMF could partly resolve the conflict between the stellar mass density and cosmic star formation history.

  1. Analysis of Lamarckian Evolution in Morphologically Evolving Robots

    NARCIS (Netherlands)

    Jelisavcic, Milan; Kiesel, Rafael; Glette, Kyrre; Haasdijk, Evert; Eiben, A.E.

    Evolving robot morphologies implies the need for lifetime learning so that newborn robots can learn to manipulate their bodies. An individual’s morphology will obviously combine traits of all its parents; it must adapt its own controller to suit its morphology, and cannot rely on the controller of

  2. Analysis of motility in multicellular Chlamydomonas reinhardtii evolved under predation.

    Directory of Open Access Journals (Sweden)

    Margrethe Boyd

    Full Text Available The advent of multicellularity was a watershed event in the history of life, yet the transition from unicellularity to multicellularity is not well understood. Multicellularity opens up opportunities for innovations in intercellular communication, cooperation, and specialization, which can provide selective advantages under certain ecological conditions. The unicellular alga Chlamydomonas reinhardtii has never had a multicellular ancestor yet it is closely related to the volvocine algae, a clade containing taxa that range from simple unicells to large, specialized multicellular colonies. Simple multicellular structures have been observed to evolve in C. reinhardtii in response to predation or to settling rate-based selection. Structures formed in response to predation consist of individual cells confined within a shared transparent extracellular matrix. Evolved isolates form such structures obligately under culture conditions in which their wild type ancestors do not, indicating that newly-evolved multicellularity is heritable. C. reinhardtii is capable of photosynthesis, and possesses an eyespot and two flagella with which it moves towards or away from light in order to optimize input of radiant energy. Motility contributes to C. reinhardtii fitness because it allows cells or colonies to achieve this optimum. Utilizing phototaxis to assay motility, we determined that newly evolved multicellular strains do not exhibit significant directional movement, even though the flagellae of their constituent unicells are present and active. In C. reinhardtii the first steps towards multicellularity in response to predation appear to result in a trade-off between motility and differential survivorship, a trade-off that must be overcome by further genetic change to ensure long-term success of the new multicellular organism.

  3. Residual gas analysis

    International Nuclear Information System (INIS)

    Berecz, I.

    1982-01-01

    Determination of the residual gas composition in vacuum systems by a special mass spectrometric method was presented. The quadrupole mass spectrometer (QMS) and its application in thin film technology was discussed. Results, partial pressure versus time curves as well as the line spectra of the residual gases in case of the vaporization of a Ti-Pd-Au alloy were demonstrated together with the possible construction schemes of QMS residual gas analysers. (Sz.J.)

  4. Water resources and shale gas/oil production in the Appalachian Basin: critical issues and evolving developments

    Science.gov (United States)

    Kappel, William M.; Williams, John H.; Szabo, Zoltan

    2013-01-01

    Unconventional natural gas and oil resources in the United States are important components of a national energy program. While the Nation seeks greater energy independence and greener sources of energy, Federal agencies with environmental responsibilities, state and local regulators and water-resource agencies, and citizens throughout areas of unconventional shale gas development have concerns about the environmental effects of high volume hydraulic fracturing (HVHF), including those in the Appalachian Basin in the northeastern United States (fig. 1). Environmental concerns posing critical challenges include the availability and use of surface water and groundwater for hydraulic fracturing; the migration of stray gas and potential effects on overlying aquifers; the potential for flowback, formation fluids, and other wastes to contaminate surface water and groundwater; and the effects from drill pads, roads, and pipeline infrastructure on land disturbance in small watersheds and headwater streams (U.S. Government Printing Office, 2012). Federal, state, regional and local agencies, along with the gas industry, are striving to use the best science and technology to develop these unconventional resources in an environmentally safe manner. Some of these concerns were addressed in U.S. Geological Survey (USGS) Fact Sheet 2009–3032 (Soeder and Kappel, 2009) about potential critical effects on water resources associated with the development of gas extraction from the Marcellus Shale of the Hamilton Group (Ver Straeten and others, 1994). Since that time, (1) the extraction process has evolved, (2) environmental awareness related to high-volume hydraulic fracturing process has increased, (3) state regulations concerning gas well drilling have been modified, and (4) the practices used by industry to obtain, transport, recover, treat, recycle, and ultimately dispose of the spent fluids and solid waste materials have evolved. This report updates and expands on Fact Sheet 2009

  5. Electrochemistry of single nanobubbles. Estimating the critical size of bubble-forming nuclei for gas-evolving electrode reactions.

    Science.gov (United States)

    German, Sean R; Edwards, Martin A; Chen, Qianjin; Liu, Yuwen; Luo, Long; White, Henry S

    2016-12-12

    In this article, we address the fundamental question: "What is the critical size of a single cluster of gas molecules that grows and becomes a stable (or continuously growing) gas bubble during gas evolving reactions?" Electrochemical reactions that produce dissolved gas molecules are ubiquitous in electrochemical technologies, e.g., water electrolysis, photoelectrochemistry, chlorine production, corrosion, and often lead to the formation of gaseous bubbles. Herein, we demonstrate that electrochemical measurements of the dissolved gas concentration, at the instant prior to nucleation of an individual nanobubble of H 2 , N 2 , or O 2 at a Pt nanodisk electrode, can be analyzed using classical thermodynamic relationships (Henry's law and the Young-Laplace equation - including non-ideal corrections) to provide an estimate of the size of the gas bubble nucleus that grows into a stable bubble. We further demonstrate that this critical nucleus size is independent of the radius of the Pt nanodisk employed (gas. For example, the measured critical surface concentration of H 2 of ∼0.23 M at the instant of bubble formation corresponds to a critical H 2 nucleus that has a radius of ∼3.6 nm, an internal pressure of ∼350 atm, and contains ∼1700 H 2 molecules. The data are consistent with stochastic fluctuations in the density of dissolved gas, at or near the Pt/solution interface, controlling the rate of bubble nucleation. We discuss the growth of the nucleus as a diffusion-limited process and how that process is affected by proximity to an electrode producing ∼10 11 gas molecules per second. Our study demonstrates the advantages of studying a single-entity, i.e., an individual nanobubble, in understanding and quantifying complex physicochemical phenomena.

  6. DGA Clustering and Analysis: Mastering Modern, Evolving Threats, DGALab

    Directory of Open Access Journals (Sweden)

    Alexander Chailytko

    2016-05-01

    Full Text Available Domain Generation Algorithms (DGA is a basic building block used in almost all modern malware. Malware researchers have attempted to tackle the DGA problem with various tools and techniques, with varying degrees of success. We present a complex solution to populate DGA feed using reversed DGAs, third-party feeds, and a smart DGA extraction and clustering based on emulation of a large number of samples. Smart DGA extraction requires no reverse engineering and works regardless of the DGA type or initialization vector, while enabling a cluster-based analysis. Our method also automatically allows analysis of the whole malware family, specific campaign, etc. We present our system and demonstrate its abilities on more than 20 malware families. This includes showing connections between different campaigns, as well as comparing results. Most importantly, we discuss how to utilize the outcome of the analysis to create smarter protections against similar malware.

  7. Ownership of solution and and evolved gas: Technical and legal perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, M. R. [Applied Reservoir Engineering and Evaluation (Canada); Friesen, J. G. [McCarthy Tetrault (Canada)

    1995-05-01

    A recent judgement of the Alberta Court of Appeal in `Prism Petroleum Ltd. et al vs. Omega Hydrocarbons Ltd.` affirmed earlier decisions, but failed to to resolve engineering issues such as terminology, PVT behaviour, producing mechanisms, the significance of an initial GOR, gas evolution in reservoirs, classification of oil and gas wells, concurrent production, enhanced recovery requirements, solution gas conservation and the effects of offset production. Some uncertainty also remained regarding the interpretation of the wording of the lease, responsibilities for costs of drilling, completion, surface facilities, operations where there has been a trespass, unjust enrichment, estoppel and limitation periods. The uncertainties regarding these legal and engineering concerns were addressed.

  8. Exploring Twitter communication dynamics with evolving community analysis

    Directory of Open Access Journals (Sweden)

    Konstantinos Konstantinidis

    2017-02-01

    Full Text Available Online Social Networks (OSNs have been widely adopted as a means of news dissemination, event reporting, opinion expression and discussion. As a result, news and events are being constantly reported and discussed online through OSNs such as Twitter. However, the variety and scale of all the information renders manual analysis extremely cumbersome, and therefore creating a storyline for an event or news story is an effort-intensive task. The main challenge pertains to the magnitude of data to be analyzed. To this end, we propose a framework for ranking the resulting communities and their metadata on the basis of structural, contextual and evolutionary characteristics such as community centrality, textual entropy, persistence and stability. We apply the proposed framework on three Twitter datasets and demonstrate that the analysis that followed enables the extraction of new insights with respect to influential user accounts, topics of discussion and emerging trends. These insights could primarily assist the work of social and political analysis scientists and the work of journalists in their own story telling, but also highlight the limitations of existing analysis methods and pose new research questions. To our knowledge, this study is the first to investigate the ranking of dynamic communities. In addition, our findings suggest future work regarding the determination of the general context of the communities based on structure and evolutionary behavior alone.

  9. (Ca,Mg)-Carbonate and Mg-Carbonate at the Phoenix Landing Site: Evaluation of the Phoenix Lander's Thermal Evolved Gas Analyzer (TEGA) Data Using Laboratory Simulations

    Science.gov (United States)

    Sutter, B.; Ming, D. W.; Boynton, W. V.; Niles, P. B.; Morris, R. V.

    2011-01-01

    Calcium carbonate (4.5 wt. %) was detected in the soil at the Phoenix Landing site by the Phoenix Lander s The Thermal and Evolved Gas Analyzer [1]. TEGA operated at 12 mbar pressure, yet the detection of calcium carbonate is based on interpretations derived from thermal analysis literature of carbonates measured under ambient (1000 mbar) and vacuum (10(exp -3) mbar) conditions [2,3] as well as at 100 and 30 mbar [4,5] and one analysis at 12 mbar by the TEGA engineering qualification model (TEGA-EQM). Thermodynamics (Te = H/ S) dictate that pressure affects entropy ( S) which causes the temperature (Te) of mineral decomposition at one pressure to differ from Te obtained at another pressure. Thermal decomposition analyses of Fe-, Mg-, and Ca-bearing carbonates at 12 mbar is required to enhance the understanding of the TEGA results at TEGA operating pressures. The objectives of this work are to (1) evaluate the thermal and evolved gas behavior of a suite of Fe-, Mg-, Ca-carbonate minerals at 1000 and 12 mbar and (2) discuss possible emplacement mechanisms for the Phoenix carbonate.

  10. Architectural Analysis of Complex Evolving Systems of Systems

    Science.gov (United States)

    Lindvall, Mikael; Stratton, William C.; Sibol, Deane E.; Ray, Arnab; Ackemann, Chris; Yonkwa, Lyly; Ganesan, Dharma

    2009-01-01

    The goal of this collaborative project between FC-MD, APL, and GSFC and supported by NASA IV&V Software Assurance Research Program (SARP), was to develop a tool, Dynamic SAVE, or Dyn-SAVE for short, for analyzing architectures of systems of systems. The project team was comprised of the principal investigator (PI) from FC-MD and four other FC-MD scientists (part time) and several FC-MD students (full time), as well as, two APL software architects (part time), and one NASA POC (part time). The PI and FC-MD scientists together with APL architects were responsible for requirements analysis, and for applying and evaluating the Dyn-SAVE tool and method. The PI and a group of FC-MD scientists were responsible for improving the method and conducting outreach activities, while another group of FC-MD scientists were responsible for development and improvement of the tool. Oversight and reporting was conducted by the PI and NASA POC. The project team produced many results including several prototypes of the Dyn-SAVE tool and method, several case studies documenting how the tool and method was applied to APL s software systems, and several published papers in highly respected conferences and journals. Dyn-SAVE as developed and enhanced throughout this research period, is a software tool intended for software developers and architects, software integration testers, and persons who need to analyze software systems from the point of view of how it communicates with other systems. Using the tool, the user specifies the planned communication behavior of the system modeled as a sequence diagram. The user then captures and imports the actual communication behavior of the system, which is then converted and visualized as a sequence diagram by Dyn-SAVE. After mapping the planned to the actual and specifying parameter and timing constraints, Dyn-SAVE detects and highlights deviations between the planned and the actual behavior. Requirements based on the need to analyze two inter

  11. Impact of evolving greenhouse gas forcing on the warming signal in regional climate model experiments.

    Science.gov (United States)

    Jerez, S; López-Romero, J M; Turco, M; Jiménez-Guerrero, P; Vautard, R; Montávez, J P

    2018-04-03

    Variations in the atmospheric concentrations of greenhouse gases (GHG) may not be included as external forcing when running regional climate models (RCMs); at least, this is a non-regulated, non-documented practice. Here we investigate the so far unexplored impact of considering the rising evolution of the CO 2 , CH 4 , and N 2 O atmospheric concentrations on near-surface air temperature (TAS) trends, for both the recent past and the near future, as simulated by a state-of-the-art RCM over Europe. The results show that the TAS trends are significantly affected by 1-2 K century -1 , which under 1.5 °C global warming translates into a non-negligible impact of up to 1 K in the regional projections of TAS, similarly affecting projections for maximum and minimum temperatures. In some cases, these differences involve a doubling signal, laying further claim to careful reconsideration of the RCM setups with regard to the inclusion of GHG concentrations as an evolving external forcing which, for the sake of research reproducibility and reliability, should be clearly documented in the literature.

  12. Hydrodynamic characteristics of the two-phase flow field at gas-evolving electrodes: numerical and experimental studies

    Science.gov (United States)

    Liu, Cheng-Lin; Sun, Ze; Lu, Gui-Min; Yu, Jian-Guo

    2018-05-01

    Gas-evolving vertical electrode system is a typical electrochemical industrial reactor. Gas bubbles are released from the surfaces of the anode and affect the electrolyte flow pattern and even the cell performance. In the current work, the hydrodynamics induced by the air bubbles in a cold model was experimentally and numerically investigated. Particle image velocimetry and volumetric three-component velocimetry techniques were applied to experimentally visualize the hydrodynamics characteristics and flow fields in a two-dimensional (2D) plane and a three-dimensional (3D) space, respectively. Measurements were performed at different gas rates. Furthermore, the corresponding mathematical model was developed under identical conditions for the qualitative and quantitative analyses. The experimental measurements were compared with the numerical results based on the mathematical model. The study of the time-averaged flow field, three velocity components, instantaneous velocity and turbulent intensity indicate that the numerical model qualitatively reproduces liquid motion. The 3D model predictions capture the flow behaviour more accurately than the 2D model in this study.

  13. Possible Calcite and Magnesium Perchlorate Interaction in the Mars Phoenix Thermal and Evolved Gas Analyzer (TEGA)

    Science.gov (United States)

    Cannon, K. M.; Sutter, B.; Ming, D. W.; Boynton, W. V.; Quinn, R. C.

    2012-01-01

    The Mars Phoenix Lander's TEGA instrument detected a calcium carbonate phase decomposing at high temperatures (approx.700 C) from the Wicked Witch soil sample [1]. TEGA also detected a lower temperature CO2 release between 400 C and 680 C [1]. Possible explanations given for this lower temperature CO2 release include thermal decomposition of Mg or Fe carbonates, a zeolitictype desorption reaction, or combustion of organic compounds in the soil [2]. The detection of 0.6 wt % soluble perchlorate by the Wet Chemistry Laboratory (WCL) on Phoenix [3] has implications for the possibility of organic molecules in the soil. Ming et al. [4] demonstrated that perchlorates could have oxidized organic compounds to CO2 in TEGA, preventing detection of their characteristic mass fragments. Here, we propose that a perchlorate salt and calcium carbonate present in martian soil reacted to produce the 400 C - 680 C TEGA CO2 release. The parent salts of the perchlorate on Mars are unknown, but geochemical models using WCL data support the possible dominance of Mg-perchlorate salts [5]. Mg(ClO4)2 6H2O is the stable phase at ambient martian conditions [6], and breaks down at lower temperatures than carbonates giving off Cl2 and HCl gas [7,8]. Devlin and Herley [7] report two exotherms at 410-478 C and 473-533 C which correspond to the decomposition of Mg(ClO4)2.

  14. Buffer gas cooling and mixture analysis

    Science.gov (United States)

    Patterson, David S.; Doyle, John M.

    2018-03-06

    An apparatus for spectroscopy of a gas mixture is described. Such an apparatus includes a gas mixing system configured to mix a hot analyte gas that includes at least one analyte species in a gas phase into a cold buffer gas, thereby forming a supersaturated mixture to be provided for spectroscopic analysis.

  15. Analysis of the evolvement of contact wire wear irregularity in railway catenary based on historical data

    NARCIS (Netherlands)

    Wang, H.; Nunez Vicencio, Alfredo; Liu, Zhigang; Song, Yang; Duan, Fuchuan; Dollevoet, R.P.B.J.

    2017-01-01

    This paper studies the evolvement of the wear irregularity of contact wire using wire thickness data measured yearly from a section of railway catenary. The power spectral density and time–frequency representation based on the wavelet transform are employed for data analysis, with an emphasis on

  16. Life-cycle analysis of shale gas and natural gas.

    Energy Technology Data Exchange (ETDEWEB)

    Clark, C.E.; Han, J.; Burnham, A.; Dunn, J.B.; Wang, M. (Energy Systems); ( EVS)

    2012-01-27

    The technologies and practices that have enabled the recent boom in shale gas production have also brought attention to the environmental impacts of its use. Using the current state of knowledge of the recovery, processing, and distribution of shale gas and conventional natural gas, we have estimated up-to-date, life-cycle greenhouse gas emissions. In addition, we have developed distribution functions for key parameters in each pathway to examine uncertainty and identify data gaps - such as methane emissions from shale gas well completions and conventional natural gas liquid unloadings - that need to be addressed further. Our base case results show that shale gas life-cycle emissions are 6% lower than those of conventional natural gas. However, the range in values for shale and conventional gas overlap, so there is a statistical uncertainty regarding whether shale gas emissions are indeed lower than conventional gas emissions. This life-cycle analysis provides insight into the critical stages in the natural gas industry where emissions occur and where opportunities exist to reduce the greenhouse gas footprint of natural gas.

  17. The Detection of Evolved Oxygen from the Rocknest Eolian Bedform Material by the Sample Analysis at Mars(SAM) instrument at the Mars Curiosity Landing Site

    Science.gov (United States)

    Sutter, B.; Archer, D.; Ming, D.; Eigenbrode, J. L.; Franz, H.; Glavin, D. P.; McAdam, A.; Mahaffy, P.; Stern, J.; Navarro-Gonzalex, R.; hide

    2013-01-01

    The Sample Analysis at Mars (SAM) instrument onboard the Curiosity rover detected an O2 gas release from the Rocknest eolain bedform (Fig. 1). The detection of perchlorate (ClO4-) by the Mars Phoenix Lander s Wet Chemistry Laboratory (WCL) [1] suggests that perchlorate is a possible candidate for evolved O2 release detected by SAM. The perchlorate would also serve as a source of chlorine in the chlorinated hydrocarbons detected by the SAM quadrupole mass spectrometer (QMS) and gas chromatography/mass spectrometer (GCMS) [2,3]. Chlorates (ClO3-) [4,5] and/or superoxides [6] may also be sources of evolved O2 from the Rocknest materials. The work objectives are to 1) evaluate the O2 release temperatures from Rocknest materials, 2) compare these O2 release temperatures with a series of perchlorates and chlorates, and 3) evaluate superoxide O2- sources and possible perchlorate interactions with other Rocknest phases during QMS analysis.

  18. Evolving Cuban-CARICOM relations : a comparative cost/benefit analysis

    Directory of Open Access Journals (Sweden)

    Michael Erisman

    1995-01-01

    Full Text Available Survey of the basic developmental dynamics involved in the evolving Cuban-CARICOM relationship. On the basis of a cost-risk/benefit analysis, the author provides some projections regarding the future of this relationship. He concludes that there appear sufficient potential benefits for both sides to deepen the relationship. Cuban-CARICOM integration, however, has no top priority for either partner.

  19. Gas analysis modeling system forecast for the Energy Modeling Forum North American Natural Gas Market Study

    International Nuclear Information System (INIS)

    Mariner-Volpe, B.; Trapmann, W.

    1989-01-01

    The Gas Analysis Modeling System is a large computer-based model for analyzing the complex US natural gas industry, including production, transportation, and consumption activities. The model was developed and first used in 1982 after the passage of the NGPA, which initiated a phased decontrol of most natural gas prices at the wellhead. The categorization of gas under the NGPA and the contractual nature of the natural gas market, which existed at the time, were primary factors in the development of the basic structure of the model. As laws and regulations concerning the natural gas market have changed, the model has evolved accordingly. Recent increases in competition in the wellhead market have also led to changes in the model. GAMS produces forecasts of natural gas production, consumption, and prices annually through 2010. It is an engineering-economic model that incorporates several different mathematical structures in order to represent the interaction of the key groups involved in the natural gas market. GAMS has separate supply and demand components that are equilibrated for each year of the forecast by means of a detailed transaction network

  20. OPIC Greenhouse Gas Emissions Analysis Details

    Data.gov (United States)

    Overseas Private Investment Corporation — Summary project inventory with independent analysis to quantify the greenhouse gas ("GHG") emissions directly attributable to projects to which the Overseas Private...

  1. Reactions Involving Calcium and Magnesium Sulfates as Potential Sources of Sulfur Dioxide During MSL SAM Evolved Gas Analyses

    Science.gov (United States)

    McAdam, A. C.; Knudson, C. A.; Sutter, B.; Franz, H. B.; Archer, P. D., Jr.; Eigenbrode, J. L.; Ming, D. W.; Morris, R. V.; Hurowitz, J. A.; Mahaffy, P. R.; hide

    2016-01-01

    The Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments on the Mars Science Laboratory (MSL) have analyzed several subsamples of 860 C). Sulfides or Fe sulfates were detected by CheMin (e.g., CB, MJ, BK) and could contribute to the high temperature SO2 evolution, but in most cases they are not present in enough abundance to account for all of the SO2. This additional SO2 could be largely associated with x-ray amorphous material, which comprises a significant portion of all samples. It can also be attributed to trace S phases present below the CheMin detection limit, or to reactions which lower the temperatures of SO2 evolution from sulfates that are typically expected to thermally decompose at temperatures outside the SAM temperature range (e.g., Ca and Mg sulfates). Here we discuss the results of SAM-like laboratory analyses targeted at understanding this last possibility, focused on understanding if reactions of HCl or an HCl evolving phase (oxychlorine phases, chlorides, etc.) and Ca and Mg sulfates can result in SO2 evolution in the SAM temperature range.

  2. Insights into the growth rate of spatially evolving plane turbulent free-shear layers from 2D vortex-gas simulations

    Science.gov (United States)

    Suryanarayanan, Saikishan; Narasimha, Roddam

    2017-02-01

    Although the free-shear or mixing layer has been a subject of extensive research over nearly a century, there are certain fundamental issues that remain controversial. These include the influence of initial and downstream conditions on the flow, the effect of velocity ratio across the layer, and the nature of any possible coupling between small scale dynamics and the large scale evolution of layer thickness. In the spirit of the temporal vortex-gas simulations of Suryanarayanan et al. ["Free turbulent shear layer in a point vortex gas as a problem in nonequilibrium statistical mechanics," Phys. Rev. E 89, 013009 (2014)], we revisit the simple 2D inviscid vortex-gas model with extensive computations and detailed analysis, in order to gain insights into some of the above issues. Simulations of the spatially evolving vortex-gas shear layer are carried out at different velocity ratios using a computational model based on the work of Basu et al. ["Vortex sheet simulation of a plane canonical mixing layer," Comput. Fluids 21, 1-30 (1992) and "Modelling plane mixing layers using vortex points and sheets," Appl. Math. Modell. 19, 66-75 (1995)], but with a crucial improvement that ensures conservation of global circulation. The simulations show that the conditions imposed at the origin of the free shear layer and at the exit to the computational domain can affect flow evolution in their respective downstream and upstream neighbourhoods, the latter being particularly strong in the single stream limit. In between these neighbourhoods at the ends is a regime of universal self-preserving growth rate given by a universal function of velocity ratio. The computed growth rates are generally located within the scatter of experimental data on plane mixing layers and closely agree with recent high Reynolds number experiments and 3D large eddy simulation studies. These findings support the view that observed free-shear layer growth can be largely explained by the 2D vortex dynamics of

  3. Molecular evolution in court: analysis of a large hepatitis C virus outbreak from an evolving source.

    Science.gov (United States)

    González-Candelas, Fernando; Bracho, María Alma; Wróbel, Borys; Moya, Andrés

    2013-07-19

    Molecular phylogenetic analyses are used increasingly in the epidemiological investigation of outbreaks and transmission cases involving rapidly evolving RNA viruses. Here, we present the results of such an analysis that contributed to the conviction of an anesthetist as being responsible for the infection of 275 of his patients with hepatitis C virus. We obtained sequences of the NS5B and E1-E2 regions in the viral genome for 322 patients suspected to have been infected by the doctor, and for 44 local, unrelated controls. The analysis of 4,184 cloned sequences of the E1-E2 region allowed us to exclude 47 patients from the outbreak. A subset of patients had known dates of infection. We used these data to calibrate a relaxed molecular clock and to determine a rough estimate of the time of infection for each patient. A similar analysis led to an estimate for the time of infection of the source. The date turned out to be 10 years before the detection of the outbreak. The number of patients infected was small at first, but it increased substantially in the months before the detection of the outbreak. We have developed a procedure to integrate molecular phylogenetic reconstructions of rapidly evolving viral populations into a forensic setting adequate for molecular epidemiological analysis of outbreaks and transmission events. We applied this procedure to a large outbreak of hepatitis C virus caused by a single source and the results obtained played a key role in the trial that led to the conviction of the suspected source.

  4. Thermal study of sintered (Th-U)O2 MOX pellet by a commercial thermo-gravimetric analyzer coupled with an evolved gas analyzer

    International Nuclear Information System (INIS)

    Mahanty, B.N.; Khan, F.A.; Karande, A.; Prakash, A.; Afzal, Md.; Panakkal, J.P.; Kamath, H.S.

    2010-01-01

    Full text: Fabrication of (Th-U)O 2 MOX pellets by the impregnation agglomerate pelletization (lAP) process is being explored in Advanced Fuel Fabrication Facility, BARC, Tarapur for the forthcoming Advanced Heavy Water Reactor (AHWR). High temperature thermal study of this fuel is important in order to understand the behaviour of the fuel under the operational temperature of the reactor. In this study, fabrication of ThO 2 -3%UO 2 was carried out by impregnation agglomerate pelletization process and subsequently sintered in reducing or air atmosphere. The degassed pellets were broken into small pieces and subjected to high temperature (1050 deg C-1250 deg C) heating under high pure argon gas in a commercial thermal analyzer. Subsequently the evolved gases were qualitatively analyzed by a quadrupole mass analyzer. The pellet sintered in reducing atmosphere (IAP-R) shows an increase in weight after the analysis where as the pellet sintered in oxidizing atmosphere (IAP-O) shows a decrease in final weight. The IAP-R pellet may become slightly hyper-stoichiometric on heating due to the presence of small amount of oxygen in the high pure argon gas. This is further supported by the mass spectrum at m/z 32(O 2 + ) that shows a decrease in the signal intensity as the temperature of analysis increases. The sharp decrease of the signal intensity at m/z 32(O 2 + ) started at 920 deg C temperature may be attributed to the formation of SO 2 (m/z=64) and CO 2 (m/z=44) gases. On the other hand the IAP-O pellet being hyper stoichiometric initially may lose its weight to form water on reaction with the excess oxygen on heating due to the presence ( small amount of hydrogen in the high pure argon gas. This is being supported by the appearance of small peak at m/z 18 (H 2 O + ) in the mass spectrum. The formation of SO 2 and CO 2 gases started at higher temperature in case of IAP-O pellet as compared to that of IAP-R pellet. This may be due to the higher density achieved in case of

  5. A gas conditioning and analysis system

    International Nuclear Information System (INIS)

    Busch, F.R.

    1974-01-01

    A system for carrying out a rapid analysis of explosive gas-mixtures is described. This system comprises a conduit connecting a sample taking point to a detection chamber, said chamber containing a mass of liquid into which the gas sample is discharged and being provided with a detecting unit for analyzing gases and with separate gas exit and liquid exit. The liquid is sent to a level-regulating chamber, whereas said gas exit sends the gas to a gas-stopping chamber which is in turn, connected to the conduit leading to a discharge point, and a vacuum pump for drawing up the gas sample into the system. This can be apply to nuclear power stations [fr

  6. Quantitative analysis of deuterium by gas chromatography

    International Nuclear Information System (INIS)

    Isomura, Shohei; Kaetsu, Hayato

    1981-01-01

    An analytical method for the determination of deuterium concentration in water and hydrogen gas by gas chromatography is described. HD and D 2 in a hydrogen gas sample were separated from H 2 by a column packed with Molecular Sieve 13X, using extra pure hydrogen gas as carrier. A thermal conductivity detector was used. Concentrations of deuterium were determined by comparison with standard samples. The error inherent to the present method was less a 1% on the basis of the calibration curves obtained with the standard samples. The average time required for the analysis was about 3 minutes. (author)

  7. Maintaining evolvability.

    Science.gov (United States)

    Crow, James F

    2008-12-01

    is yet to be determined. It is likely that only a case-by-case analysis will provide the answers. Despite the difficulties that complex interactions cause for evolution in Mendelian populations, such populations nevertheless evolve very well. Longlasting species must have evolved mechanisms for coping with such problems. Since such difficulties do not arise in asexual populations, a comparison of epistatic patterns in closely related sexual and asexual species might provide some important insights.

  8. Identification of fast-evolving genes in the scleractinian coral Acropora using comparative EST analysis.

    Directory of Open Access Journals (Sweden)

    Akira Iguchi

    Full Text Available To identify fast-evolving genes in reef-building corals, we performed direct comparative sequence analysis with expressed sequence tag (EST datasets from two acroporid species: Acropora palmata from the Caribbean Sea and A. millepora from the Great Barrier Reef in Australia. Comparison of 589 independent sequences from 1,421 A. palmata contigs, with 10,247 A. millepora contigs resulted in the identification of 196 putative homologues. Most of the homologous pairs demonstrated high amino acid similarities (over 90%. Comparisons of putative homologues showing low amino acid similarities (under 90% among the Acropora species to the near complete datasets from two other cnidarians (Hydra magnipapillata and Nematostella vectensis implied that some were non-orthologous. Within 86 homologous pairs, 39 exhibited dN/dS ratios significantly less than 1, suggesting that these genes are under purifying selection associated with functional constraints. Eight independent genes showed dN/dS ratios exceeding 1, while three deviated significantly from 1, suggesting that these genes may play important roles in the adaptive evolution of Acropora. Our results also indicated that CEL-III lectin was under positive selection, consistent with a possible role in immunity or symbiont recognition. Further studies are needed to clarify the possible functions of the genes under positive selection to provide insight into the evolutionary process of corals.

  9. Identification of fast-evolving genes in the scleractinian coral Acropora using comparative EST analysis.

    Science.gov (United States)

    Iguchi, Akira; Shinzato, Chuya; Forêt, Sylvain; Miller, David J

    2011-01-01

    To identify fast-evolving genes in reef-building corals, we performed direct comparative sequence analysis with expressed sequence tag (EST) datasets from two acroporid species: Acropora palmata from the Caribbean Sea and A. millepora from the Great Barrier Reef in Australia. Comparison of 589 independent sequences from 1,421 A. palmata contigs, with 10,247 A. millepora contigs resulted in the identification of 196 putative homologues. Most of the homologous pairs demonstrated high amino acid similarities (over 90%). Comparisons of putative homologues showing low amino acid similarities (under 90%) among the Acropora species to the near complete datasets from two other cnidarians (Hydra magnipapillata and Nematostella vectensis) implied that some were non-orthologous. Within 86 homologous pairs, 39 exhibited dN/dS ratios significantly less than 1, suggesting that these genes are under purifying selection associated with functional constraints. Eight independent genes showed dN/dS ratios exceeding 1, while three deviated significantly from 1, suggesting that these genes may play important roles in the adaptive evolution of Acropora. Our results also indicated that CEL-III lectin was under positive selection, consistent with a possible role in immunity or symbiont recognition. Further studies are needed to clarify the possible functions of the genes under positive selection to provide insight into the evolutionary process of corals.

  10. Probabilistic Analysis of Gas Turbine Field Performance

    Science.gov (United States)

    Gorla, Rama S. R.; Pai, Shantaram S.; Rusick, Jeffrey J.

    2002-01-01

    A gas turbine thermodynamic cycle was computationally simulated and probabilistically evaluated in view of the several uncertainties in the performance parameters, which are indices of gas turbine health. Cumulative distribution functions and sensitivity factors were computed for the overall thermal efficiency and net specific power output due to the thermodynamic random variables. These results can be used to quickly identify the most critical design variables in order to optimize the design, enhance performance, increase system availability and make it cost effective. The analysis leads to the selection of the appropriate measurements to be used in the gas turbine health determination and to the identification of both the most critical measurements and parameters. Probabilistic analysis aims at unifying and improving the control and health monitoring of gas turbine aero-engines by increasing the quality and quantity of information available about the engine's health and performance.

  11. Analysis of recent type Ia supernova data based on evolving dark energy models

    International Nuclear Information System (INIS)

    Park, Jaehong; Park, Chan-Gyung; Hwang, Jai-chan

    2011-01-01

    We study characters of recent type Ia supernova data using evolving dark energy models with changing equation-of-state parameter w. We consider a sudden-jump approximation of w for some chosen redshift spans with double transitions and constrain these models based on the Markov chain Monte Carlo method using the type Ia supernova data (Constitution, Union, Union2), together with the baryon acoustic oscillation A parameter and the cosmic microwave background shift parameter in a flat background. In the double-transition model, the Constitution data shows deviation outside 1σ from the Λ cold dark matter (ΛCDM) model at low (z < or approx. 0.2) and middle (0.2 < or approx. z < or approx. 0.4) redshift bins, whereas no such deviations are noticeable in the Union and Union2 data. By analyzing the Union members in the Constitution set, however, we show that the same difference is actually due to different calibration of the same Union sample in the Constitution set and is not due to new data added in the Constitution set. All detected deviations are within 2σ from the ΛCDM world model. From the ΛCDM mock data analysis, we quantify biases in the dark energy equation-of-state parameters induced by insufficient data with inhomogeneous distribution of data points in the redshift space and distance modulus errors. We demonstrate that the location of the peak in the distribution of arithmetic means (computed from the Markov chain Monte Carlo chain for each mock data) behaves as an unbiased estimator for the average bias, which is valid even for nonsymmetric likelihood distributions.

  12. Time-lapse misorientation maps for the analysis of electron backscatter diffraction data from evolving microstructures

    NARCIS (Netherlands)

    Wheeler, J.; Cross, A.; Drury, M.; Hough, R.M.; Mariani, E.; Piazolo, S.; Prior, D.J.

    2011-01-01

    A “time-lapse misorientation map” is defined here as a map which shows the orientation change at each point in an evolving crystalline microstructure between two different times. Electron backscatter diffraction data from in situ heating experiments can be used to produce such maps, which then

  13. Time-lapse misorientation maps for the analysis of electron backscatter diffraction data from evolving microstructures

    International Nuclear Information System (INIS)

    Wheeler, J.; Cross, A.; Drury, M.; Hough, R.M.; Mariani, E.; Piazolo, S.; Prior, D.J.

    2011-01-01

    A 'time-lapse misorientation map' is defined here as a map which shows the orientation change at each point in an evolving crystalline microstructure between two different times. Electron backscatter diffraction data from in situ heating experiments can be used to produce such maps, which then highlight areas of microstructural change and also yield statistics indicative of how far different types of boundary (with different misorientations) have moved.

  14. A miniaturized optical gas sensor for natural gas analysis

    NARCIS (Netherlands)

    Ayerden, N.P.

    2016-01-01

    The depletion of domestic reserves and the growing use of sustainable resources forces a transition from the locally produced natural gas with a well-known composition toward the ‘new’ gas with a more flexible composition in the Netherlands. For safe combustion and proper billing, the natural gas

  15. Natural gas product and strategic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Layne, A.W.; Duda, J.R.; Zammerilli, A.M.

    1993-12-31

    Product and strategic analysis at the Department of Energy (DOE)/Morgantown Energy Technology Center (METC) crosscuts all sectors of the natural gas industry. This includes the supply, transportation, and end-use sectors of the natural-gas market. Projects in the Natural Gas Resource and Extraction supply program have been integrated into a new product focus. Product development facilitates commercialization and technology transfer through DOE/industry cost-shared research, development, and demonstration (RD&D). Four products under the Resource and Extraction program include Resource and Reserves; Low Permeability Formations; Drilling, Completion, and Stimulation: and Natural Gas Upgrading. Engineering process analyses have been performed for the Slant Hole Completion Test project. These analyses focused on evaluation of horizontal-well recovery potential and applications of slant-hole technology. Figures 2 and 3 depict slant-well in situ stress conditions and hydraulic fracture configurations. Figure 4 presents Paludal Formation coal-gas production curves used to optimize the hydraulic fracture design for the slant well. Economic analyses have utilized data generated from vertical test wells to evaluate the profitability of horizontal technology for low-permeability formations in Yuma County, Colorado, and Maverick County, Texas.

  16. GAS CHROMATOGRAPHIC AND SPECTROSCOPIC ANALYSIS OF ...

    African Journals Online (AJOL)

    Peroxyformic acid prepared in-situ was employed for epoxidation of canola oil in the presence of toluene. Gas chromatographic analysis of the product revealed the following species: C16:0; C18:0; C18:1; C18:2; C18:3; monoepoxy C18:0; monoepoxy C18:1; monoepoxy C18:2; diepoxy C18:0; diepoxy C18:1 and triepoxy ...

  17. TOXRISK, Toxic Gas Release Accident Analysis

    International Nuclear Information System (INIS)

    Bennett, D.E.; Chanin, D.I.; Shiver, A.W.

    1993-01-01

    1 - Description of program or function: TOXRISK is an interactive program developed to aid in the evaluation of nuclear power plant control room habitability in the event of a nearby toxic material release. The program uses a model which is consistent with the approach described in the NRC Regulatory Guide 1.78. Release of the gas is treated as an initial puff followed by a continuous plume. The relative proportions of these as well as the plume release rate are supplied by the user. Transport of the gas is modeled as a Gaussian distribution and occurs through the action of a constant velocity, constant direction wind. Great flexibility is afforded the user in specifying the release description, meteorological conditions, relative geometry of the accident and plant, and the plant ventilation system characteristics. Two types of simulation can be performed: multiple case (parametric) studies and probabilistic analyses. Upon execution, TOXRISK presents a menu, and the user chooses between the Data Base Manager, the Multiple Case program, and the Probabilistic Study Program. The Data Base Manager provides a convenient means of storing, retrieving, and modifying blocks of data required by the analysis programs. The Multiple Case program calculates resultant gas concentrations inside the control room and presents a summary of information that describes the event for each set of conditions given. Optimally, a time history profile of inside and outside concentrations can also be produced. The Probabilistic Study program provides a means for estimating the annual probability of operator incapacitation due to toxic gas accidents on surrounding transportation routes and storage sites. 2 - Method of solution: Dispersion or diffusion of the gas during transport is described by modified Pasquill-Gifford dispersion coefficients

  18. Environmental analysis for pipeline gas demonstration plants

    Energy Technology Data Exchange (ETDEWEB)

    Stinton, L.H.

    1978-09-01

    The Department of Energy (DOE) has implemented programs for encouraging the development and commercialization of coal-related technologies, which include coal gasification demonstration-scale activities. In support of commercialization activities the Environmental Analysis for Pipeline Gas Demonstration Plants has been prepared as a reference document to be used in evaluating potential environmental and socioeconomic effects from construction and operation of site- and process-specific projects. Effluents and associated impacts are identified for six coal gasification processes at three contrasting settings. In general, impacts from construction of a high-Btu gas demonstration plant are similar to those caused by the construction of any chemical plant of similar size. The operation of a high-Btu gas demonstration plant, however, has several unique aspects that differentiate it from other chemical plants. Offsite development (surface mining) and disposal of large quantities of waste solids constitute important sources of potential impact. In addition, air emissions require monitoring for trace metals, polycyclic aromatic hydrocarbons, phenols, and other emissions. Potential biological impacts from long-term exposure to these emissions are unknown, and additional research and data analysis may be necessary to determine such effects. Possible effects of pollutants on vegetation and human populations are discussed. The occurrence of chemical contaminants in liquid effluents and the bioaccumulation of these contaminants in aquatic organisms may lead to adverse ecological impact. Socioeconomic impacts are similar to those from a chemical plant of equivalent size and are summarized and contrasted for the three surrogate sites.

  19. Trends in the analysis of natural gas by capillary gas chromatography

    NARCIS (Netherlands)

    Cramers, C.A.M.G.; Rossum, van G.J.

    1986-01-01

    The importance of correct determination of physical and chemical properties of natural gas is evident. The calculation of calorific value or hydrocarbon dew point requires detailed analysis as can be provided by gas chromatography. Analysis by gas chromatography is a necessary complement to direct

  20. Quantitative Analysis of Oxygen Gas Exhausted from Anode through In Situ Measurement during Electrolytic Reduction

    Directory of Open Access Journals (Sweden)

    Eun-Young Choi

    2017-01-01

    Full Text Available Quantitative analysis by in situ measurement of oxygen gas evolved from an anode was employed to monitor the progress of electrolytic reduction of simulated oxide fuel in a molten Li2O–LiCl salt. The electrolytic reduction of 0.6 kg of simulated oxide fuel was performed in 5 kg of 1.5 wt.% Li2O–LiCl molten salt at 650°C. Porous cylindrical pellets of simulated oxide fuel were used as the cathode by loading a stainless steel wire mesh cathode basket. A platinum plate was employed as the anode. The oxygen gas evolved from the anode was exhausted to the instrumentation for in situ measurement during electrolytic reduction. The instrumentation consisted of a mass flow controller, pump, wet gas meter, and oxygen gas sensor. The oxygen gas was successfully measured using the instrumentation in real time. The measured volume of the oxygen gas was comparable to the theoretically calculated volume generated by the charge applied to the simulated oxide fuel.

  1. What Causes Environmental Inequalities and Related Health Effects? An Analysis of Evolving Concepts

    Science.gov (United States)

    Kruize, Hanneke; Droomers, Mariël; van Kamp, Irene; Ruijsbroek, Annemarie

    2014-01-01

    Early environmental justice studies were exposure-oriented, lacked an integrated approach, and did not address the health impact of environmental inequalities. A coherent conceptual framework, needed to understand and tackle environmental inequalities and the related health effects, was lacking. We analyzed the more recent environmental justice literature to find out how conceptual insights have evolved. The conceptual framework of the WHO Commission on Social Determinants of Health (CSDH) was analyzed for additional explanations for environmental inequalities and the related health effects. This paper points out that recent environmental justice studies have broadened their scope by incorporating a broader set of physical and social environmental indicators, and by focusing on different geographic levels and on health impacts of environmental inequalities. The CSDH framework provided additional elements such as the role of structural determinants, the role of health-related behavior in relation to the physical and social environment, access to health care, as well as the life course perspective. Incorporating elements of the CSDH framework into existing environmental justice concepts, and performing more empirical research on the interactions between the different determinants at different geographical levels would further improve our understanding of environmental inequalities and their health effects and offer new opportunities for policy action. PMID:24886752

  2. What Causes Environmental Inequalities and Related Health Effects? An Analysis of Evolving Concepts

    Directory of Open Access Journals (Sweden)

    Hanneke Kruize

    2014-05-01

    Full Text Available Early environmental justice studies were exposure-oriented, lacked an integrated approach, and did not address the health impact of environmental inequalities. A coherent conceptual framework, needed to understand and tackle environmental inequalities and the related health effects, was lacking. We analyzed the more recent environmental justice literature to find out how conceptual insights have evolved. The conceptual framework of the WHO Commission on Social Determinants of Health (CSDH was analyzed for additional explanations for environmental inequalities and the related health effects. This paper points out that recent environmental justice studies have broadened their scope by incorporating a broader set of physical and social environmental indicators, and by focusing on different geographic levels and on health impacts of environmental inequalities. The CSDH framework provided additional elements such as the role of structural determinants, the role of health-related behavior in relation to the physical and social environment, access to health care, as well as the life course perspective. Incorporating elements of the CSDH framework into existing environmental justice concepts, and performing more empirical research on the interactions between the different determinants at different geographical levels would further improve our understanding of environmental inequalities and their health effects and offer new opportunities for policy action.

  3. Simple gas chromatographic method for furfural analysis.

    Science.gov (United States)

    Gaspar, Elvira M S M; Lopes, João F

    2009-04-03

    A new, simple, gas chromatographic method was developed for the direct analysis of 5-hydroxymethylfurfural (5-HMF), 2-furfural (2-F) and 5-methylfurfural (5-MF) in liquid and water soluble foods, using direct immersion SPME coupled to GC-FID and/or GC-TOF-MS. The fiber (DVB/CAR/PDMS) conditions were optimized: pH effect, temperature, adsorption and desorption times. The method is simple and accurate (RSDfurfurals will contribute to characterise and quantify their presence in the human diet.

  4. Microfabricated Gas Phase Chemical Analysis Systems

    International Nuclear Information System (INIS)

    FRYE-MASON, GREGORY CHARLES; HELLER, EDWIN J.; HIETALA, VINCENT M.; KOTTENSTETTE, RICHARD; LEWIS, PATRICK R.; MANGINELL, RONALD P.; MATZKE, CAROLYN M.; WONG, CHUNGNIN C.

    1999-01-01

    A portable, autonomous, hand-held chemical laboratory ((micro)ChemLab(trademark)) is being developed for trace detection (ppb) of chemical warfare (CW) agents and explosives in real-world environments containing high concentrations of interfering compounds. Microfabrication is utilized to provide miniature, low-power components that are characterized by rapid, sensitive and selective response. Sensitivity and selectivity are enhanced using two parallel analysis channels, each containing the sequential connection of a front-end sample collector/concentrator, a gas chromatographic (GC) separator, and a surface acoustic wave (SAW) detector. Component design and fabrication and system performance are described

  5. Quantitative risk analysis preoperational of gas pipeline

    Energy Technology Data Exchange (ETDEWEB)

    Manfredi, Carlos; Bispo, Gustavo G.; Esteves, Alvaro [Gie S.A., Buenos Aires (Argentina)

    2009-07-01

    The purpose of this analysis is to predict how it can be affected the individual risk and the public's general security due to the operation of a gas pipeline. In case that the single or social risks are considered intolerable, compared with the international standards, to be recommended measures of mitigation of the risk associated to the operation until levels that can be considered compatible with the best practices in the industry. The quantitative risk analysis calculates the probability of occurrence of an event based on the frequency of occurrence of the same one and it requires a complex mathematical treatment. The present work has as objective to develop a calculation methodology based on the previously mentioned publication. This calculation methodology is centered in defining the frequencies of occurrence of events, according to representative database of each case in study. Besides, it settles down the consequences particularly according to the considerations of each area and the different possibilities of interferences with the gas pipeline in study. For each one of the interferences a typical curve of ignition probabilities is developed in function from the distance to the pipe. (author)

  6. Solar-gas systems impact analysis study

    Science.gov (United States)

    Neill, C. P.; Hahn, E. F.; Loose, J. C.; Poe, T. E.; Hirshberg, A. S.; Haas, S.; Preble, B.; Halpin, J.

    1984-07-01

    The impacts of solar/gas technologies on gas consumers and on gas utilities were measured separately and compared against the impacts of competing gas and electric systems in four climatic regions of the U.S. A methodology was developed for measuring the benefits or penalties of solar/gas systems on a combined basis for consumers sand distribution companies. It is shown that the combined benefits associated with solar/gas systems are generally greatest when the systems are purchased by customers who would have otherwise chosen high-efficiency electric systems (were solar/gas systems not available in the market place). The role of gas utilities in encouraging consumer acceptance of solar/gas systems was also examined ion a qualitative fashion. A decision framework for analyzing the type and level of utility involvement in solar/gas technologies was developed.

  7. The Reach-and-Evolve Algorithm for Reachability Analysis of Nonlinear Dynamical Systems

    NARCIS (Netherlands)

    P.J. Collins (Pieter); A. Goldsztejn

    2008-01-01

    htmlabstractThis paper introduces a new algorithm dedicated to the rigorous reachability analysis of nonlinear dynamical systems. The algorithm is initially presented in the context of discrete time dynamical systems, and then extended to continuous time dynamical systems driven by ODEs. In

  8. Nondestructive fission gas release measurement and analysis

    International Nuclear Information System (INIS)

    O'Leary, P.M.; Packard, D.R.

    1993-01-01

    Siemens Power Corporation (SPC) has performed reactor poolside gamma scanning measurements of fuel rods for fission gas release (FGR) detection for more than 10 yr. The measurement system has been previously described. Over the years, the data acquisition system, the method of spectrum analysis, and the means of reducing spectrum interference have been significantly improved. A personal computer (PC)-based multichannel analyzer (MCA) package is used to collect, display, and store high-resolution gamma-ray spectra measured in the fuel rod plenum. A PC spread sheet is used to fit the measured spectra and compute sample count rates after Compton background subtraction. A Zircaloy plenum spacer is often used to reduce positron annihilation interference that can arise from the INCONEL reg-sign plenum spring used in SPC-manufactured fuel rods

  9. Thermal analysis of a gas centrifuge

    International Nuclear Information System (INIS)

    Andrade, D.A.; Bastos, J.L.F.; Maiorino, J.R.

    1996-01-01

    The centrifuge separation efficiency is the result of the composition of the centrifuge field to the secondary flow in the axial direction near to the rotor wall. For a given machine, the centrifuge field can not be altered and the effort to augment the separation efficiency should be concentrated on the secondary flow. The secondary flow has a mechanical and a thermal component. The mechanical component is due to the deceleration of the gas at the scoop region. The thermal component is due to the temperature differences at the rotor. This paper presents a thermal model of a centrifuge in order to understand the main heat transfer mechanisms and to establish the boundary conditions for a fluid flow computer code. The heat transfer analysis takes into account conduction at the structure parts of the rotor and shell, radiation with multi-reflections between the rotor and the shell, and convection to the ambient. (author)

  10. Gas chromatographic analysis of volatiles in fluid and gas inclusions

    Science.gov (United States)

    Andrawes, F.; Holzer, G.; Roedder, E.; Gibson, E.K.; Oro, John

    1984-01-01

    Most geological samples and some synthetic materials contain fluid inclusions. These inclusions preserve for us tiny samples of the liquid and/or the gas phase that was present during formation, although in some cases they may have undergone significant changes from the original material. Studies of the current composition of the inclusions provide data on both the original composition and the change since trapping.These inclusions are seldom larger than 1 millimeter in diameter. The composition varies from a single major compound (e.g., water) in a single phase to a very complex mixture in one or more phases. The concentration of some of the compounds present may be at trace levels.We present here some analyses of inclusions in a variety of geological samples, including diamonds. We used a sample crusher and a gas chromatography—mass spectrometry (GC—MS) system to analyze for organic and inorganic volatiles present as major to trace constituents in inclusions. The crusher is a hardened stainless-steel piston cylinder apparatus with tungsten carbide crusing surfaces, and is operated in a pure helium atmosphere at a controlled temperature.Samples ranging from 1 mg to 1 g were crushed and the released volatiles were analyzed using multi-chromatographic columns and detectors, including the sensitive helium ionization detector. Identification of the GC peaks was carried out by GC—MS. This combination of procedures has been shown to provide geochemically useful information on the process involved in the history of the samples analyzed.

  11. Review of Sector and Regional Trends in U.S. Electricity Markets. Focus on Natural Gas. Natural Gas and the Evolving U.S. Power Sector Monograph Series. Number 1 of 3

    Energy Technology Data Exchange (ETDEWEB)

    Logan, Jeffrey; Medlock III, Kenneth B.; Boyd, William C.

    2015-10-15

    This study explores dynamics related to natural gas use at the national, sectoral, and regional levels, with an emphasis on the power sector. It relies on a data set from SNL Financial to analyze recent trends in the U.S. power sector at the regional level. The research aims to provide decision and policy makers with objective and credible information, data, and analysis that informs their discussions of a rapidly changing energy system landscape. This study also summarizes regional changes in natural gas demand within the power sector. The transition from coal to natural gas is occurring rapidly along the entire eastern portion of the country, but is relatively stagnant in the central and western regions. This uneven shift is occurring due to differences in fuel price costs, renewable energy targets, infrastructure constraints, historical approach to regulation, and other factors across states.

  12. Evolved H II regions

    International Nuclear Information System (INIS)

    Churchwell, E.

    1975-01-01

    A probable evolutionary sequence of H II regions based on six distinct types of observed objects is suggested. Two examples which may deviate from this idealized sequence, are discussed. Even though a size-mean density relation of H II regions can be used as a rough indication of whether a nebula is very young or evolved, it is argued that such a relation is not likely to be useful for the quantitative assignment of ages to H II regions. Evolved H II regions appear to fit into one of four structural types: rings, core-halos, smooth structures, and irregular or filamentary structures. Examples of each type are given with their derived physical parameters. The energy balance in these nebulae is considered. The mass of ionized gas in evolved H II regions is in general too large to trace the nebula back to single compact H II regions. Finally, the morphological type of the Galaxy is considered from its H II region content. 2 tables, 2 figs., 29 refs

  13. Evaluation And Analysis of Natural Gas Rates

    International Nuclear Information System (INIS)

    Taheri, Ali Akbar

    1999-01-01

    Natural gas is considered as a preferred fuel and its utility is growing every day in the country (Iran). The usage of natural gas has increased from 3.5 to 44 billion cubic meters from 1980 to 1997, respectively. Currently, 4 million residences and most of the industrial sector are being provided with the pipelined natural gas. Because of the tremendous increase in consumption, it is necessary to give the needed considerations to natural gas rate structure. The objective of the paper is to 1.Evaluate the fundamentals and principal methods used for rate structures. 2. Identification of effective components. 3. Analyze the current rates including connection fees and other customer charges

  14. Gas hydrates forming and decomposition conditions analysis

    Directory of Open Access Journals (Sweden)

    А. М. Павленко

    2017-07-01

    Full Text Available The concept of gas hydrates has been defined; their brief description has been given; factors that affect the formation and decomposition of the hydrates have been reported; their distribution, structure and thermodynamic conditions determining the gas hydrates formation disposition in gas pipelines have been considered. Advantages and disadvantages of the known methods for removing gas hydrate plugs in the pipeline have been analyzed, the necessity of their further studies has been proved. In addition to the negative impact on the process of gas extraction, the hydrates properties make it possible to outline the following possible fields of their industrial use: obtaining ultrahigh pressures in confined spaces at the hydrate decomposition; separating hydrocarbon mixtures by successive transfer of individual components through the hydrate given the mode; obtaining cold due to heat absorption at the hydrate decomposition; elimination of the open gas fountain by means of hydrate plugs in the bore hole of the gushing gasser; seawater desalination, based on the hydrate ability to only bind water molecules into the solid state; wastewater purification; gas storage in the hydrate state; dispersion of high temperature fog and clouds by means of hydrates; water-hydrates emulsion injection into the productive strata to raise the oil recovery factor; obtaining cold in the gas processing to cool the gas, etc.

  15. Iron-Rich Carbonates as the Potential Source of Evolved CO2 Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater

    Science.gov (United States)

    Sutter, B.; Heil, E.; Rampe, E. B.; Morris, R. V.; Ming, D. W.; Archer, P. D.; Eigenbrode, J. L.; Franz, H. B.; Glavin, D. P.; McAdam, A. C.; hide

    2015-01-01

    The Sample Analysis at Mars (SAM) instrument detected at least 4 distinct CO2 release during the pyrolysis of a sample scooped from the Rocknest (RN) eolian deposit. The highest peak CO2 release temperature (478-502 C) has been attributed to either a Fe-rich carbonate or nano-phase Mg-carbonate. The objective of this experimental study was to evaluate the thermal evolved gas analysis (T/EGA) characteristics of a series of terrestrial Fe-rich carbonates under analog SAM operating conditions to compare with the RN CO2 releases. Natural Fe-rich carbonates (<53 microns) with varying Fe amounts (Fe(0.66)X(0.34)- to Fe(0.99)X(0.01)-CO3, where X refers to Mg and/or Mn) were selected for T/EGA. The carbonates were heated from 25 to 715 C (35 C/min) and evolved CO2 was measured as a function of temperature. The highest Fe containing carbonates (e.g., Fe(0.99)X(0.01)-CO3) yielded CO2 peak temperatures between 466-487 C, which is consistent with the high temperature RN CO2 release. The lower Fe-bearing carbonates (e.g., Fe(0.66)X(0.34)CO3) did not have peak CO2 release temperatures that matched the RN peak CO2 temperatures; however, their entire CO2 releases did occur within RN temperature range of the high temperature CO2 release. Results from this laboratory analog analysis demonstrate that the high temperature RN CO2 release is consistent with Fe-rich carbonate (approx.0.7 to 1 wt.% FeCO3). The similar RN geochemistry with other materials in Gale Crater and elsewhere on Mars (e.g., Gusev Crater, Meridiani) suggests that up to 1 wt. % Fe-rich carbonate may occur throughout the Gale Crater region and could be widespread on Mars. The Rocknest Fe-carbonate may have formed from the interaction of reduced Fe phases (e.g., Fe2+ bearing olivine) with atmospheric CO2 and transient water. Alternatively, the Rocknest Fe-carbonate could be derived by eolian processes that have eroded distally exposed deep crustal material that possesses Fe-carbonate that may have formed through

  16. Review of statistical analysis of trapped gas

    International Nuclear Information System (INIS)

    Schmittroth, F.A.

    1996-01-01

    A review was conducted of trapped gas estimates in Hanford waste tanks. Tank waste levels were found to correlate with barometric pressure changes giving the possibility to infer amounts of trapped gas. Previous models of the tank waste level were extended to include other phenomena such as evaporation in a more complete description of tank level changes

  17. Analysis of Adsorbed Natural Gas Tank Technology

    Science.gov (United States)

    Knight, Ernest; Schultz, Conrad; Rash, Tyler; Dohnke, Elmar; Stalla, David; Gillespie, Andrew; Sweany, Mark; Seydel, Florian; Pfeifer, Peter

    With gasoline being an ever decreasing finite resource and with the desire to reduce humanity's carbon footprint, there has been an increasing focus on innovation of alternative fuel sources. Natural gas burns cleaner, is more abundant, and conforms to modern engines. However, storing compressed natural gas (CNG) requires large, heavy gas cylinders, which limits space and fuel efficiency. Adsorbed natural gas (ANG) technology allows for much greater fuel storage capacity and the ability to store the gas at a much lower pressure. Thus, ANG tanks are much more flexible in terms of their size, shape, and weight. Our ANG tank employs monolithic nanoporous activated carbon as its adsorbent material. Several different configurations of this Flat Panel Tank Assembly (FPTA) along with a Fuel Extraction System (FES) were examined to compare with the mass flow rate demands of an engine.

  18. Development of a natural Gas Systems Analysis Model (GSAM)

    International Nuclear Information System (INIS)

    Godec, M.; Haas, M.; Pepper, W.; Rose, J.

    1993-01-01

    Recent dramatic changes in natural gas markets have significant implications for the scope and direction of DOE's upstream as well as downstream natural gas R ampersand D. Open access transportation changes the way gas is bought and sold. The end of the gas deliverability surplus requires increased reserve development above recent levels. Increased gas demand for power generation and other new uses changes the overall demand picture in terms of volumes, locations and seasonality. DOE's Natural Gas Strategic Plan requires that its R ampersand D activities be evaluated for their ability to provide adequate supplies of reasonably priced gas. Potential R ampersand D projects are to be evaluated using a full fuel cycle, benefit-cost approach to estimate likely market impact as well as technical success. To assure R ampersand D projects are evaluated on a comparable basis, METC has undertaken the development of a comprehensive natural gas technology evaluation framework. Existing energy systems models lack the level of detail required to estimate the impact of specific upstream natural gas technologies across the known range of geological settings and likely market conditions. Gas Systems Analysis Model (GSAM) research during FY 1993 developed and implemented this comprehensive, consistent natural gas system evaluation framework. Rather than a isolated research activity, however, GSAM represents the integration of many prior and ongoing natural gas research efforts. When complete, it will incorporate the most current resource base description, reservoir modeling, technology characterization and other geologic and engineering aspects developed through recent METC and industry gas R ampersand D programs

  19. Automated metabolic gas analysis systems: a review.

    Science.gov (United States)

    Macfarlane, D J

    2001-01-01

    The use of automated metabolic gas analysis systems or metabolic measurement carts (MMC) in exercise studies is common throughout the industrialised world. They have become essential tools for diagnosing many hospital patients, especially those with cardiorespiratory disease. Moreover, the measurement of maximal oxygen uptake (VO2max) is routine for many athletes in fitness laboratories and has become a defacto standard in spite of its limitations. The development of metabolic carts has also facilitated the noninvasive determination of the lactate threshold and cardiac output, respiratory gas exchange kinetics, as well as studies of outdoor activities via small portable systems that often use telemetry. Although the fundamental principles behind the measurement of oxygen uptake (VO2) and carbon dioxide production (VCO2) have not changed, the techniques used have, and indeed, some have almost turned through a full circle. Early scientists often employed a manual Douglas bag method together with separate chemical analyses, but the need for faster and more efficient techniques fuelled the development of semi- and full-automated systems by private and commercial institutions. Yet, recently some scientists are returning back to the traditional Douglas bag or Tissot-spirometer methods, or are using less complex automated systems to not only save capital costs, but also to have greater control over the measurement process. Over the last 40 years, a considerable number of automated systems have been developed, with over a dozen commercial manufacturers producing in excess of 20 different automated systems. The validity and reliability of all these different systems is not well known, with relatively few independent studies having been published in this area. For comparative studies to be possible and to facilitate greater consistency of measurements in test-retest or longitudinal studies of individuals, further knowledge about the performance characteristics of these

  20. Using Willie's Acid-Base Box for Blood Gas Analysis

    Science.gov (United States)

    Dietz, John R.

    2011-01-01

    In this article, the author describes a method developed by Dr. William T. Lipscomb for teaching blood gas analysis of acid-base status and provides three examples using Willie's acid-base box. Willie's acid-base box is constructed using three of the parameters of standard arterial blood gas analysis: (1) pH; (2) bicarbonate; and (3) CO[subscript…

  1. Thermodynamic DFT analysis of natural gas.

    Science.gov (United States)

    Neto, Abel F G; Huda, Muhammad N; Marques, Francisco C; Borges, Rosivaldo S; Neto, Antonio M J C

    2017-08-01

    Density functional theory was performed for thermodynamic predictions on natural gas, whose B3LYP/6-311++G(d,p), B3LYP/6-31+G(d), CBS-QB3, G3, and G4 methods were applied. Additionally, we carried out thermodynamic predictions using G3/G4 averaged. The calculations were performed for each major component of seven kinds of natural gas and to their respective air + natural gas mixtures at a thermal equilibrium between room temperature and the initial temperature of a combustion chamber during the injection stage. The following thermodynamic properties were obtained: internal energy, enthalpy, Gibbs free energy and entropy, which enabled us to investigate the thermal resistance of fuels. Also, we estimated an important parameter, namely, the specific heat ratio of each natural gas; this allowed us to compare the results with the empirical functions of these parameters, where the B3LYP/6-311++G(d,p) and G3/G4 methods showed better agreements. In addition, relevant information on the thermal and mechanic resistance of natural gases were investigated, as well as the standard thermodynamic properties for the combustion of natural gas. Thus, we show that density functional theory can be useful for predicting the thermodynamic properties of natural gas, enabling the production of more efficient compositions for the investigated fuels. Graphical abstract Investigation of the thermodynamic properties of natural gas through the canonical ensemble model and the density functional theory.

  2. Disgust: Evolved function and structure

    NARCIS (Netherlands)

    Tybur, J.M.; Lieberman, D.; Kurzban, R.; DeScioli, P.

    2013-01-01

    Interest in and research on disgust has surged over the past few decades. The field, however, still lacks a coherent theoretical framework for understanding the evolved function or functions of disgust. Here we present such a framework, emphasizing 2 levels of analysis: that of evolved function and

  3. Thermodynamic Analysis of Supplementary-Fired Gas Turbine Cycles

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Henriksen, Ulrik Birk; Qvale, Einar Bjørn

    2002-01-01

    This paper presents an analysis of the possibilities for improving the efficiency of an indirectly biomass-fired gas turbine (IBFGT) by supplementary direct gas-firing. The supplementary firing may be based on natural gas, biogas, or pyrolysis gas. {The interest in this cycle arise from a recent...... demonstration of a two-stage gasification process through construction of several plants.} A preliminary analysis of the ideal recuperated Brayton cycle shows that for this cycle any supplementary firing will have a marginal efficiency of unity per extra unit of fuel. The same result is obtained...

  4. Strength analysis of copper gas pipeline span

    OpenAIRE

    Ianevski, Philipp

    2016-01-01

    The purpose of the study was to analyze the stresses in a gas pipeline. While analyzing piping systems located inside building were used. Calculation of the strength of a gas pipeline is done by using information of the thickness of pipe walls, by choosing the suitable material, inner and outer diameter for the pipeline. Data for this thesis was collected through various internet sources and different books. From the study and research, the final results were reached and calculations were ...

  5. Systems Analysis of In-Space Manufacturing Applications for the International Space Station and the Evolvable Mars Campaign

    Science.gov (United States)

    Owens, Andrew C.; De Weck, Olivier L.

    2016-01-01

    Maintenance logistics support is a significant challenge for extended human operations in space, especially for missions beyond Low Earth Orbit (LEO). For missions to Mars (such as NASA's Evolvable Mars Campaign (EMC)), where timely resupply or abort in the event of emergency will not be possible, maintenance logistics mass is directly linked to the Probability of Loss of Crew (P(LoC)), and the cost of driving down risk is an exponential increase in mass requirements. The logistics support strategies that have maintained human operations in LEO will not be effective for these deep space missions. In-Space Manufacturing (ISM) is a promising technological solution that could reduce logistics requirements, mitigate risks, and augment operational capabilities, enabling Earth- independent human spaceflight. This paper reviews maintenance logistics challenges for spaceflight operations in LEO and beyond, and presents a summary of selected results from a systems analysis of potential ISM applications for the ISS and EMC. A quantitative modeling framework and sample assessment of maintenance logistics and risk reduction potential of this new technology is also presented and discussed.

  6. Analysis of natural gas supply strategies at Fort Drum

    International Nuclear Information System (INIS)

    Stucky, D.J.; Shankle, S.A.; Anderson, D.M.

    1992-07-01

    This analysis investigates strategies for Fort Drum to acquire a reliable natural gas supply while reducing its gas supply costs. The purpose of this study is to recommend an optimal supply mix based on the life-cycle costs of each strategy analyzed. In particular, this study is intended to provide initial guidance as to whether or not the building and operating of a propane-air mixing station is a feasible alternative to the current gas acquisition strategy. The analysis proceeded by defining the components of supply (gas purchase, gas transport, supplemental fuel supply); identifying alternative options for each supply component; constructing gas supply strategies from different combinations of the options available for each supply component and calculating the life-cycle costs of each supply strategy under a set of different scenarios reflecting the uncertainty of future events

  7. Gas analysis during the chemical vapor deposition of carbon

    International Nuclear Information System (INIS)

    Lieberman, M.L.; Noles, G.T.

    1973-01-01

    Gas chromatographic analyses were performed during the chemical vapor deposition of carbon in both isothermal and thermal gradient systems. Such data offer insight into the gas phase processes which occur during deposition and the interrelations which exist between gas composition, deposition rate, and resultant structure of the deposit. The results support a carbon CVD model presented previously. The application of chromatographic analysis to research, development, and full-scale facilities is shown. (U.S.)

  8. A Stirling engine analysis method based upon moving gas nodes

    Science.gov (United States)

    Martini, W. R.

    1986-01-01

    A Lagrangian nodal analysis method for Stirling engines (SEs) is described, validated, and applied to a conventional SE and an isothermalized SE (with fins in the hot and cold spaces). The analysis employs a constant-mass gas node (which moves with respect to the solid nodes during each time step) instead of the fixed gas nodes of Eulerian analysis. The isothermalized SE is found to have efficiency only slightly greater than that of a conventional SE.

  9. Correlation between arterial blood gas analysis and peripheral blood gas analysis in acid-base unbalance state

    Directory of Open Access Journals (Sweden)

    Hyun Lee Kim

    2012-06-01

    Full Text Available Acid-base unbalance is most common problem in severe ill patient, especially in condition of abnormal renal function state. Acid-base unbalances are respiratory acidosis, respiratory alkalosis, metabolic acidosis, and metabolic alkalosis. Metabolic acidosis is frequently appeared in clinical state. Arterial blood gas analysis is considered as a basic test to the intensive care unit patient and emergency state. Recently some researches were done, comparing with arterial blood gas analysis and venous blood gas analysis. Because of venous blood sampling is safer than arterial blood gas analysis, and beside not so different among them for detecting pH, pCO2, HCO3, except pO2 measuring. This research was done in emergency room, and for explaining no different between arterial blood gas analysis and peripheral blood gas analysis result in acid-base unbalance state patient. Especially in kidney functions decreased state. : The study was done from March, 2010 to January, 2011. The object was 89 peoples who came to emergency room for treating internal medicine problem. (Women 53, average age: 66.7±12.1 Then compare between arterial blood gas analysis and peripheral blood gas analysis. Result: The mean arterial minus venous difference for pH, pCO2, and bicarbonate was −0.0170, 2.6528, and 0.6124. Bland-Altman plot was done for predicting agreement of two groups, and the scale was pH −2.95 to 4.17, pCO2 −4.45 to 9.76, bicarbonate −2.95 to 4.16, in 95% relative. Conclusion: The peripheral blood gas pH, pCO2, bicarbonate level is almost same as arterial blood gas analysis results. And enough to measuring acid-base unbalance state, in absent of arterial blood testing.

  10. EVOLVE 2014 International Conference

    CERN Document Server

    Tantar, Emilia; Sun, Jian-Qiao; Zhang, Wei; Ding, Qian; Schütze, Oliver; Emmerich, Michael; Legrand, Pierrick; Moral, Pierre; Coello, Carlos

    2014-01-01

    This volume encloses research articles that were presented at the EVOLVE 2014 International Conference in Beijing, China, July 1–4, 2014.The book gathers contributions that emerged from the conference tracks, ranging from probability to set oriented numerics and evolutionary computation; all complemented by the bridging purpose of the conference, e.g. Complex Networks and Landscape Analysis, or by the more application oriented perspective. The novelty of the volume, when considering the EVOLVE series, comes from targeting also the practitioner’s view. This is supported by the Machine Learning Applied to Networks and Practical Aspects of Evolutionary Algorithms tracks, providing surveys on new application areas, as in the networking area and useful insights in the development of evolutionary techniques, from a practitioner’s perspective. Complementary to these directions, the conference tracks supporting the volume, follow on the individual advancements of the subareas constituting the scope of the confe...

  11. Use of emanation thermal analysis and evolved gas analysis in thermal study of zinc(II) benzoate complex compounds

    Czech Academy of Sciences Publication Activity Database

    Findoráková, L.; Györyová, K.; Večerníková, Eva; Balek, V.

    2009-01-01

    Roč. 98, č. 3 (2009), s. 765-769 ISSN 1388-6150 Institutional research plan: CEZ:AV0Z40320502 Keywords : zinc(II) benzoate * caffeine * urea * thermogravimetry Subject RIV: CA - Inorganic Chemistry Impact factor: 1.587, year: 2009

  12. Thermal analysis elements of liquefied gas storage tanks

    Science.gov (United States)

    Yanvarev, I. A.; Krupnikov, A. V.

    2017-08-01

    Tasks of solving energy and resource efficient usage problems, both for oil producing companies and for companies extracting and transporting natural gas, are associated with liquefied petroleum gas technology development. Improving the operation efficiency of liquefied products storages provides for conducting structural, functional, and appropriate thermal analysis of tank parks in the general case as complex dynamic thermal systems.

  13. State and trends of ionization gas analysis. 1

    International Nuclear Information System (INIS)

    Leonhardt, J.W.; Grosse, H.J.; Popp, P.

    1980-01-01

    The ionization gas analysis makes use of the fact that the ionization-induced conductivity of gases and gas mixtures changes with the composition of such mixtures. A general description is given of ionization detectors based on this principle and theory, properties, and main fields of application of electron capture detectors are discussed

  14. Improvement of gas chromatographic analysis for organic acids and ...

    African Journals Online (AJOL)

    Yomi

    2010-08-27

    Aug 27, 2010 ... short retention time and fair recognition peak of the compounds were obtained under the ... GC for acid and solvent analysis from ABE fermentation ... FID was kept at 230°C. Nitrogen gas was used as a carrier gas at a.

  15. State and trends of ionization gas analysis. 3

    International Nuclear Information System (INIS)

    Leonhardt, J.W.; Grosse, H.J.; Popp, P.

    1980-01-01

    Theory, properties, and main fields of application of noble gas detectors are discussed. The theory and design of the indirect electron mobility detector is presented. Conclusions are drawn with regard to possibilities of further development of detectors for the ionization gas analysis

  16. Development of a natural Gas Systems Analysis Model (GSAM)

    International Nuclear Information System (INIS)

    1994-02-01

    Lacking a detailed characterization of the resource base and a comprehensive borehole-to-burnertip evaluation model of the North American natural gas system, past R ampersand D, tax and regulatory policies have been formulated without a full understanding of their likely direct and indirect impacts on future gas supply and demand. The recent disappearance of the deliverability surplus, pipeline deregulation, and current policy debates about regulatory initiatives in taxation, environmental compliance and leasing make the need for a comprehensive gas evaluation system critical. Traditional econometric or highly aggregated energy models are increasingly regarded as unable to incorporate available geologic detail and explicit technology performance and costing algorithms necessary to evaluate resource-technology-economic interactions in a market context. The objective of this research is to create a comprehensive, non-proprietary, microcomputer model of the North American natural gas system. GSAM explicitly evaluates the key components of the natural gas system, including resource base, exploration and development, extraction technology performance and costs, transportation and storage and end use. The primary focus is the detailed characterization of the resource base at the reservoir and sub-reservoir level and the impact of alternative extraction technologies on well productivity and economics. GSAM evaluates the complex interactions of current and alternative future technology and policy initiatives in the context of the evolving gas markets. Scheduled for completion in 1995, a prototype is planned for early 1994. ICF Resources reviewed relevant natural gas upstream, downstream and market models to identify appropriate analytic capabilities to incorporate into GSAM. We have reviewed extraction technologies to better characterize performance and costs in terms of GSAM parameters

  17. Analysis of the industrial treatment of gas

    Energy Technology Data Exchange (ETDEWEB)

    Shirkovskiy, A.I.; Belaya, N.N.; Nad, Z.

    1982-01-01

    Mathematical models, algorithms and programs are developed for calculation of the thermodynamic conditions of the operation of installations for low temperature separation, which made it possible, in an example of the gas condensate deposit of western Shatlyk, to predict the operation of low temperature separation installations to 1984.

  18. Numerical Analysis of Dusty-Gas Flows

    Science.gov (United States)

    Saito, T.

    2002-02-01

    This paper presents the development of a numerical code for simulating unsteady dusty-gas flows including shock and rarefaction waves. The numerical results obtained for a shock tube problem are used for validating the accuracy and performance of the code. The code is then extended for simulating two-dimensional problems. Since the interactions between the gas and particle phases are calculated with the operator splitting technique, we can choose numerical schemes independently for the different phases. A semi-analytical method is developed for the dust phase, while the TVD scheme of Harten and Yee is chosen for the gas phase. Throughout this study, computations are carried out on SGI Origin2000, a parallel computer with multiple of RISC based processors. The efficient use of the parallel computer system is an important issue and the code implementation on Origin2000 is also described. Flow profiles of both the gas and solid particles behind the steady shock wave are calculated by integrating the steady conservation equations. The good agreement between the pseudo-stationary solutions and those from the current numerical code validates the numerical approach and the actual coding. The pseudo-stationary shock profiles can also be used as initial conditions of unsteady multidimensional simulations.

  19. Detection of Evolved Carbon Dioxide in the Rocknest Eolian Bedform by the Sample Analysis at Mars(SAM) Instrument at the Mars Curiosity Landing Site

    Science.gov (United States)

    Sutter, B.; Archer, D.; McAdam, A.; Franz, H.; Ming, D. W.; Eigenbrode, J. L.; Glavin, D. P.; Mahaffy, P.; Stern, J.; Navarro-Gonzalez, R.

    2013-01-01

    The Sample Analysis at Mars (SAM) instrument detected four releases of carbon dioxide (CO2) that ranged from 100 to 700 C from the Rocknest eolian bedform material (Fig. 1). Candidate sources of CO2 include adsorbed CO2, carbonate(s), combusted organics that are either derived from terrestrial contamination and/or of martian origin, occluded or trapped CO2, and other sources that have yet to be determined. The Phoenix Lander s Thermal Evolved Gas Analyzer (TEGA) detected two CO2 releases (400-600, 700-840 C) [1,2]. The low temperature release was attributed to Fe- and/or Mg carbonates [1,2], per-chlorate interactions with carbonates [3], nanophase carbonates [4] and/or combusted organics [1]. The high temperature CO2 release was attributed to a calcium bearing carbonate [1,2]. No evidence of a high temperature CO2 release similar to the Phoenix material was detected in the Rocknest materials by SAM. The objectives of this work are to evaluate the temperature and total contribution of each Rocknest CO2 release and their possible sources. Four CO2 releases from the Rocknest material were detected by SAM. Potential sources of CO2 are adsorbed CO2, (peak 1) and Fe/Mg carbonates (peak 4). Only a fraction of peaks 2 and 3 (0.01 C wt.%) may be partially attributed to combustion of organic contamination. Meteoritic organics mixed in the Rocknest bedform could be present, but the peak 2 and 3 C concentration (approx.0.21 C wt. %) is likely too high to be attributed solely to meteoritic organic C. Other inorganic sources of C such as interactions of perchlorates and carbonates and sources yet to be identified will be evaluated to account for CO2 released from the thermal decomposition of Rocknest material.

  20. Analysis of expression in the Anopheles gambiae developing testes reveals rapidly evolving lineage-specific genes in mosquitoes

    Directory of Open Access Journals (Sweden)

    Krzywinski Jaroslaw

    2009-07-01

    Full Text Available Abstract Background Male mosquitoes do not feed on blood and are not involved in delivery of pathogens to humans. Consequently, they are seldom the subjects of research, which results in a very poor understanding of their biology. To gain insights into male developmental processes we sought to identify genes transcribed exclusively in the reproductive tissues of male Anopheles gambiae pupae. Results Using a cDNA subtraction strategy, five male-specifically or highly male-biased expressed genes were isolated, four of which remain unannotated in the An. gambiae genome. Spatial and temporal expression patterns suggest that each of these genes is involved in the mid-late stages of spermatogenesis. Their sequences are rapidly evolving; however, two genes possess clear homologs in a wide range of taxa and one of these probably acts in a sperm motility control mechanism conserved in many organisms, including humans. The other three genes have no match to sequences from non-mosquito taxa, thus can be regarded as orphans. RNA in situ hybridization demonstrated that one of the orphans is transcribed in spermatids, which suggests its involvement in sperm maturation. Two other orphans have unknown functions. Expression analysis of orthologs of all five genes indicated that male-biased transcription was not conserved in the majority of cases in Aedes and Culex. Conclusion Discovery of testis-expressed orphan genes in mosquitoes opens new prospects for the development of innovative control methods. The orphan encoded proteins may represent unique targets of selective anti-mosquito sterilizing agents that will not affect non-target organisms.

  1. Analysis of expression in the Anopheles gambiae developing testes reveals rapidly evolving lineage-specific genes in mosquitoes.

    Science.gov (United States)

    Krzywinska, Elzbieta; Krzywinski, Jaroslaw

    2009-07-06

    Male mosquitoes do not feed on blood and are not involved in delivery of pathogens to humans. Consequently, they are seldom the subjects of research, which results in a very poor understanding of their biology. To gain insights into male developmental processes we sought to identify genes transcribed exclusively in the reproductive tissues of male Anopheles gambiae pupae. Using a cDNA subtraction strategy, five male-specifically or highly male-biased expressed genes were isolated, four of which remain unannotated in the An. gambiae genome. Spatial and temporal expression patterns suggest that each of these genes is involved in the mid-late stages of spermatogenesis. Their sequences are rapidly evolving; however, two genes possess clear homologs in a wide range of taxa and one of these probably acts in a sperm motility control mechanism conserved in many organisms, including humans. The other three genes have no match to sequences from non-mosquito taxa, thus can be regarded as orphans. RNA in situ hybridization demonstrated that one of the orphans is transcribed in spermatids, which suggests its involvement in sperm maturation. Two other orphans have unknown functions. Expression analysis of orthologs of all five genes indicated that male-biased transcription was not conserved in the majority of cases in Aedes and Culex. Discovery of testis-expressed orphan genes in mosquitoes opens new prospects for the development of innovative control methods. The orphan encoded proteins may represent unique targets of selective anti-mosquito sterilizing agents that will not affect non-target organisms.

  2. Gas Chromatography-Mass Spectrometric Analysis and Insecticidal ...

    African Journals Online (AJOL)

    HP

    Original Research Article. Gas Chromatography-Mass Spectrometric Analysis and ... into a natural fumigant/insecticide for the control of stored product insects. Keywords: Mallotus ..... stability as well as reduce cost. ACKNOWLEDGEMENT.

  3. Gas Chromatography-Mass Spectrometric Analysis of Nematicidal ...

    African Journals Online (AJOL)

    Gas Chromatography-Mass Spectrometric Analysis of Nematicidal Essential Oil of Valeriana ... Tropical Journal of Pharmaceutical Research ... have a potential to be developed to natural nematicides for the control of cereal cyst nematodes.

  4. Elimination of chromatographic and mass spectrometric problems in GC-MS analysis of Lavender essential oil by multivariate curve resolution techniques: Improving the peak purity assessment by variable size moving window-evolving factor analysis.

    Science.gov (United States)

    Jalali-Heravi, Mehdi; Moazeni-Pourasil, Roudabeh Sadat; Sereshti, Hassan

    2015-03-01

    In analysis of complex natural matrices by gas chromatography-mass spectrometry (GC-MS), many disturbing factors such as baseline drift, spectral background, homoscedastic and heteroscedastic noise, peak shape deformation (non-Gaussian peaks), low S/N ratio and co-elution (overlapped and/or embedded peaks) lead the researchers to handle them to serve time, money and experimental efforts. This study aimed to improve the GC-MS analysis of complex natural matrices utilizing multivariate curve resolution (MCR) methods. In addition, to assess the peak purity of the two-dimensional data, a method called variable size moving window-evolving factor analysis (VSMW-EFA) is introduced and examined. The proposed methodology was applied to the GC-MS analysis of Iranian Lavender essential oil, which resulted in extending the number of identified constituents from 56 to 143 components. It was found that the most abundant constituents of the Iranian Lavender essential oil are α-pinene (16.51%), camphor (10.20%), 1,8-cineole (9.50%), bornyl acetate (8.11%) and camphene (6.50%). This indicates that the Iranian type Lavender contains a relatively high percentage of α-pinene. Comparison of different types of Lavender essential oils showed the composition similarity between Iranian and Italian (Sardinia Island) Lavenders. Published by Elsevier B.V.

  5. Environmental analysis of natural gas life cycle

    International Nuclear Information System (INIS)

    Riva, A.; D'Angelosante, S.; Trebeschi, C.

    2000-01-01

    Life Cycle Assessment is a method aimed at identifying the environmental effects connected with a given product, process or activity during its whole life cycle. The evaluation of published studies and the application of the method to electricity production with fossil fuels, by using data from published databases and data collected by the gas industry, demonstrate the importance and difficulties to have reliable and updated data required for a significant life cycle assessment. The results show that the environmental advantages of natural gas over the other fossil fuels in the final use stage increase still further if the whole life cycle of the fuels, from production to final consumption, is taken into account [it

  6. Evolvable synthetic neural system

    Science.gov (United States)

    Curtis, Steven A. (Inventor)

    2009-01-01

    An evolvable synthetic neural system includes an evolvable neural interface operably coupled to at least one neural basis function. Each neural basis function includes an evolvable neural interface operably coupled to a heuristic neural system to perform high-level functions and an autonomic neural system to perform low-level functions. In some embodiments, the evolvable synthetic neural system is operably coupled to one or more evolvable synthetic neural systems in a hierarchy.

  7. Microstructuring of piezoresistive cantilevers for gas detection and analysis

    International Nuclear Information System (INIS)

    Sarov, Y.; Sarova, V.; Bitterlich, Ch.; Richter, O.; Guliyev, E.; Zoellner, J.-P.; Rangelow, I. W.; Andok, R.; Bencurova, A.

    2011-01-01

    In this work we report on a design and fabrication of cantilevers for gas detection and analysis. The cantilevers have expanded area of interaction with the gas, while the signal transduction is realized by an integrated piezoresistive deflection sensor, placed at the narrowed cantilever base with highest stress along the cantilever. Moreover, the cantilevers have integrated bimorph micro-actuator detection in a static and dynamic mode. The cantilevers are feasible as pressure, temperature and flow sensors and under chemical functionalization - for gas recognition, tracing and composition analysis. (authors)

  8. Numerical Analysis on Transient of Steam-gas Pressurizer

    International Nuclear Information System (INIS)

    Kim, Jong-Won; Lee, Yeon-Gun; Park, Goon-Cherl

    2008-01-01

    In nuclear reactors, various pressurizers are adopted to satisfy their characteristics and uses. The additional active systems such as heater, pressurizer cooler, spray and insulator are essential for a steam or a gas pressurizer. With a steam-gas pressurizer, additional systems are not required due to the use of steam and non-condensable gas as pressure-buffering materials. The steam-gas pressurizer in integrated small reactors experiences very complicated thermal-hydraulic phenomena. To ensure the integrity of this pressurizer type, the analysis on the transient behavior of the steam-gas pressure is indispensable. For this purpose, the steam-gas pressurizer model is introduced to predict the accurate system pressure. The proposed model includes bulk flashing, rainout, inter-region heat and mass transfer and wall condensation with non-condensable gas. However, the ideal gas law is not applied because of significant interaction at high pressure between steam and non-condensable gas. The results obtained from this proposed model agree with those from pressurizer tests. (authors)

  9. Evolving lithospheric flexure and paleotopography of the Pyrenean Orogen from 3D flexural modeling and basin analysis

    Science.gov (United States)

    Curry, M. E.; van der Beek, P.; Huismans, R. S.; Muñoz, J. A.

    2017-12-01

    The Pyrenees are an asymmetric, doubly-vergent orogen with retro- and pro- foreland basins that preserve a record of deformation since the Mesozoic. The extensive research and exploration efforts on the mountain belt and flanking foreland basins provide an exceptional dataset for investigating geodynamics and surface processes over large spatial and temporal scales in western Europe. We present the results of a numerical modeling study investigating the spatio-temporal variation in lithospheric flexure in response to the developing orogen. We employ a finite element method to model the 3D flexural deformation of the lithosphere beneath the Pyrenean orogen since the onset of convergence in the late Cretaceous. Using subsurface, geophysical, and structural data, we describe the evolving geometry of both the French Aquitaine and Spanish Ebro foreland basins at the present (post-orogenic), the mid-Eocene (peak orogenic), the Paleocene (early orogenic), and the end of the Cretaceous (pre- to early orogenic). The flexural modeling provides insight into how both the rigidity of the lithosphere and the paleotopographic load have varied over the course of orogenesis to shape the basin geometry. We find that the overriding European plate has higher rigidity than the subducting Iberian plate, with modern Effective Elastic Thickness (EET) values of 20 ± 2 and 12 ± 2 km, respectively. Modeling indicates that the modern rigidity of both plates decreases westward towards the Bay of Biscay. The lithospheric rigidity has increased by 50% since the Mesozoic with early Cenozoic EET values of 13 ± 2 and 8 ± 1 km for the European and Iberian plates, respectively. The topographic load began increasing with convergence in the late Cretaceous, reaching modern levels in the central and eastern Pyrenees by the Eocene. In contrast, the topographic load in the western Pyrenees was 70% of the modern value in the Eocene, and experienced topographic growth through the Oligo-Miocene. The

  10. Gas analysis by computer-controlled microwave rotational spectrometry

    International Nuclear Information System (INIS)

    Hrubesh, L.W.

    1978-01-01

    Microwave rotational spectrometry has inherently high resolution and is thus nearly ideal for qualitative gas mixture analysis. Quantitative gas analysis is also possible by a simplified method which utilizes the ease with which molecular rotational transitions can be saturated at low microwave power densities. This article describes a computer-controlled microwave spectrometer which is used to demonstrate for the first time a totally automated analysis of a complex gas mixture. Examples are shown for a complete qualitative and quantitative analysis, in which a search of over 100 different compounds is made in less than 7 min, with sensitivity for most compounds in the 10 to 100 ppm range. This technique is expected to find increased use in view of the reduced complexity and increased reliabiity of microwave spectrometers and because of new energy-related applications for analysis of mixtures of small molecules

  11. Greenhouse gas and energy analysis of substitute natural gas from biomass for space heat

    Energy Technology Data Exchange (ETDEWEB)

    Pucker, J.; Jungmeier, G. [JOANNEUM RESEARCH Forschungsgesellschaft mbH, RESOURCES - Institute for Water, Energy and Sustainability, Steyrergasse 17, 8010 Graz (Austria); Zwart, R. [Energy Research Centre of The Netherlands (ECN), Westerduinweg 3, 1755 LE Petten (Netherlands)

    2012-03-15

    In this paper, the greenhouse gas and energy balances of the production and use for space heating of substitute natural gas from biomass (bio-SNG) for space heat are analysed. These balances are compared to the use of natural gas and solid biomass as wood chips to provide the same service. The reduction of the greenhouse gas emissions (CO{sub 2}-eq.) - carbon dioxide, methane and nitrous oxide - and of the fossil primary energy use is investigated in a life cycle assessment (LCA). This assessment was performed for nine systems for bio-SNG; three types of gasification technologies (O{sub 2}-blown entrained flow, O{sub 2}-blown circulating fluidised bed and air-steam indirect gasification) with three different types of feedstock (forest residues, miscanthus and short rotation forestry). The greenhouse gas analysis shows that forest residues using the air-steam indirect gasification technology result in the lowest greenhouse gas emissions (in CO{sub 2}-eq. 32 kg MWh{sup -1} of heat output). This combination results in 80% reduction of greenhouse gas emissions when compared to natural gas and a 29% reduction of greenhouse gases if the forest residues were converted to wood chips and combusted. The gasification technologies O{sub 2}-blown entrained flow and O{sub 2}-blown circulating fluidised bed gasification have higher greenhouse gas emissions that range between in CO{sub 2}-eq. 41 to 75 kg MWh{sup -1} of heat output depending on the feedstock. When comparing feedstocks in the bio-SNG systems, miscanthus had the highest greenhouse gas emissions bio-SNG systems producing in CO2-eq. 57-75 kg MWh{sup -1} of heat output. Energy analysis shows that the total primary energy use is higher for bio-SNG systems (1.59-2.13 MWh MWh{sup -1} of heat output) than for the reference systems (in 1.37-1.51 MWh MWh{sup -1} of heat output). However, with bio-SNG the fossil primary energy consumption is reduced compared to natural gas. For example, fossil primary energy use is reduced by

  12. Analysis of pollutants in air and water using gas chromatography and headspace gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Stenner, H.

    1980-01-01

    The combination 'personal sampling' with headspace gas chromatography to determine traces of formaldehyde, phenol and benzene in air is investigated in this work, with the aim of developing maximum workplace concentration values (MWL values). Further possible applications of gas chromatography in trace analysis in the environmentally protected area. The analysis of chromium in waste waters (Cr III as acetyl acetonate complex) is investigated as further possible application, whereby optimum conditions are obtained. A modified flame ionization detector was used to increase the detection sensitivity.

  13. Ambient Field Analysis at Groningen Gas Field

    Science.gov (United States)

    Spica, Z.; Nakata, N.; Beroza, G. C.

    2016-12-01

    We analyze continuous ambient-field data at Groningen gas field (Netherlands) through cross-correlation processing. The Groningen array is composed of 75 shallow boreholes with 6 km spacing, which contain a 3C surface accelerometer and four 5-Hz 3C borehole geophones spaced at 50 m depth intervals. We successfully retrieve coherent waves from ambient seismic field on the 9 components between stations. Results show high SNR signal in the frequency range of 0.125-1 Hz, and the ZZ, ZR, RZ, RR and TT components show much stronger wave energy than other components as expected. This poster discuss the different type of waves retrieved, the utility of the combination of borehole and surface observations, future development as well as the importance to compute the 9 components of the Green's tensor to better understand the wave field propriety with ambient noise.

  14. Suitability of selected free-gas and dissolved-gas sampling containers for carbon isotopic analysis.

    Science.gov (United States)

    Eby, P; Gibson, J J; Yi, Y

    2015-07-15

    Storage trials were conducted for 2 to 3 months using a hydrocarbon and carbon dioxide gas mixture with known carbon isotopic composition to simulate typical hold times for gas samples prior to isotopic analysis. A range of containers (both pierced and unpierced) was periodically sampled to test for δ(13)C isotopic fractionation. Seventeen containers were tested for free-gas storage (20°C, 1 atm pressure) and 7 containers were tested for dissolved-gas storage, the latter prepared by bubbling free gas through tap water until saturated (20°C, 1 atm) and then preserved to avoid biological activity by acidifying to pH 2 with phosphoric acid and stored in the dark at 5°C. Samples were extracted using valves or by piercing septa, and then introduced into an isotope ratio mass spectrometer for compound-specific δ(13)C measurements. For free gas, stainless steel canisters and crimp-top glass serum bottles with butyl septa were most effective at preventing isotopic fractionation (pierced and unpierced), whereas silicone and PTFE-butyl septa allowed significant isotopic fractionation. FlexFoil and Tedlar bags were found to be effective only for storage of up to 1 month. For dissolved gas, crimp-top glass serum bottles with butyl septa were again effective, whereas silicone and PTFE-butyl were not. FlexFoil bags were reliable for up to 2 months. Our results suggest a range of preferred containers as well as several that did not perform very well for isotopic analysis. Overall, the results help establish better QA/QC procedures to avoid isotopic fractionation when storing environmental gas samples. Recommended containers for air transportation include steel canisters and glass serum bottles with butyl septa (pierced and unpierced). Copyright © 2015 John Wiley & Sons, Ltd.

  15. Molecular gas analysis by Raman scattering in intracavity laser configuration

    International Nuclear Information System (INIS)

    Benner, R.E.; Andrade, J.D.; Van Wagenen, R.A.; Westenskow, D.R.

    1987-01-01

    A system is described for the near simultaneous analysis and quantitation of selected multiple polyatomic gases in a gas sample by Raman light scattering comprising in combination: (a) laser means capable of producing a polarized laser beam of a selected wavelength containing a laser cavity the laser cavity containing a plasma tube and wherein one end of the laser cavity contains a high reflectivity output coupler mirror; (b) a gas sampling cell located within the laser cavity between the plasma tube and the output coupler mirror, the cell having opposing parallel end windows interconnected by a continuous sidewall. The end windows and sidewall define a longitudinal gas chamber oriented such that, when the laser beam is activated, the laser beam is coincident with and traverses the axis of the longitudinal gas chamber, the end windows being positioned to be substantially normal to the axis of the longitudinal gas cell chamber. The cell also has opposing, aligned side windows in the sidewall parallel to and on either side of the axis of the longitudinal gas chamber. The gas cell further contains inlet and outlet means communicating with the chamber to pass a sample gas through the cell

  16. Exergy analysis of waste emissions from gas flaring

    Directory of Open Access Journals (Sweden)

    Olawale Saheed ISMAIL

    2016-07-01

    Full Text Available Gas flaring produces a stream of waste gases at high temperature and pressure which contains carbon monoxide, Hydrogen Sulphide etc. The resultant effect of which is detrimental to our planet and, consequently, to the life of both the living and the non-living things. It’s well known that gas flaring contributes in no small measure to the global warming. Exergy analysis is applied in this work to analyze waste emissions from gas flaring so as to have a model through which impact of gas flaring can be measured. The study considers both the thermo-mechanical exergy and the chemical exergy of these gases. Relevant data on gas flaring activities in the Niger-Delta region of Nigeria between the periods of fifteen (15 years was obtained from the Nigerian National Petroleum Corporation (NNPC. A computer program (Exergy Calculator was developed based on the equations generated in the Model. Exergy associated with gas flaring activities in Nigeria between the periods of 1998 through 2012 was calculated. The results show that 1 mscf (in thousand cubic feet of flared gases generate 0.000041 MWh of energy leading to a value of 440158.607 MWh of energy for the period under review.The analysis provides important conclusions and recommendations for improving oil platforms operationsin in order to safeguard the environment, health of the populace, and maximize recovered exergy from gas flaring.

  17. Gas Hydrate-Sediment Morphologies Revealed by Pressure Core Analysis

    Science.gov (United States)

    Holland, M.; Schultheiss, P.; Roberts, J.; Druce, M.

    2006-12-01

    Analysis of HYACINTH pressure cores collected on IODP Expedition 311 and NGHP Expedition 1 showed gas hydrate layers, lenses, and veins contained in fine-grained sediments as well as gas hydrate contained in coarse-grained layers. Pressure cores were recovered from sediments on the Cascadia Margin off the North American West Coast and in the Krishna-Godavari Basin in the Western Bay of Bengal in water depths of 800- 1400 meters. Recovered cores were transferred to laboratory chambers without loss of pressure and nondestructive measurements were made at in situ pressures and controlled temperatures. Gamma density, P-wave velocity, and X-ray images showed evidence of grain-displacing and pore-filling gas hydrate in the cores. Data highlights include X-ray images of fine-grained sediment cores showing wispy subvertical veins of gas hydrate and P-wave velocity excursions corresponding to grain-displacing layers and pore-filling layers of gas hydrate. Most cores were subjected to controlled depressurization experiments, where expelled gas was collected, analyzed for composition, and used to calculate gas hydrate saturation within the core. Selected cores were stored under pressure for postcruise analysis and subsampling.

  18. Gas generation and migration analysis for TRU waste disposal system

    International Nuclear Information System (INIS)

    Ando, Kenichi; Noda, Masaru; Yamamoto, Mikihiko; Mihara, Morihiro

    2005-09-01

    In TRU waste disposal system, significant quantities of gases may be generated due to metal corrosion, radiolysis effect and microorganism activities. It is therefore recommended that the potential impact of gas generation and migration on TRU waste repository should be evaluated. In this study, gas generation rates were calculated in the repository and gas migration analysis in the disposal system were carried out using two phase flow model with results of gas generation rates. First, the time dependencies of gas generation rate in each TRU waste repositories were evaluated based on amounts of metal, organic matter and radioactivity. Next, the accumulation pressure of gases and expelled pore water volume nuclides in the repository were calculated by TOUGH2 code. After that, the results showed that the increase of gas pressure was the range of 1.3 to 1.4 MPa. In the repository with and without buffer, the rate of expelled pore water was 0.006 - 0.009 m 3 /y and 0.018 - 0.24m 3 /y, respectively. In addition, the radioactive gas migration through the repository and geosphere are evaluated. And re-saturation analysis is also performed to evaluate the initial condition of the system. (author)

  19. The Use of Gas Chromatography for Biogas Analysis

    Science.gov (United States)

    Andersen, Amanda; Seeley, John; Aurandt, Jennifer

    2010-04-01

    Energy from natural gas accounts for 24 percent of energy consumed in the US. Natural gas is a robust form of energy which is rich in methane content and is low in impurities. This quality suggests that it is a very clean and safe gas; it can be used in providing heat, a source for cooking, and in powering vehicles. The downside is that it is a non-renewable resource. On the contrary, methane rich gas that is produced by the breakdown of organic material in an anaerobic environment, called biogas, is a renewable energy source. This research focuses on the gas analysis portion of the creation of the anaerobic digestion and verification laboratory where content and forensic analysis of biogas is performed. Gas Chromatography is implemented as the optimal analytical tool for quantifying the components of the biogas including methane, carbon dioxide, hydrogen sulfide and siloxanes. In addition, the problems associated with the undesirable components are discussed. Anaerobic digestion of primary sludge has consistently produced about 55 percent methane; future goals of this research include studying different substrates to increase the methane yield and decrease levels of impurities in the gas.

  20. Genome-Wide Analysis in Three Fusarium Pathogens Identifies Rapidly Evolving Chromosomes and Genes Associated with Pathogenicity

    Science.gov (United States)

    Sperschneider, Jana; Gardiner, Donald M.; Thatcher, Louise F.; Lyons, Rebecca; Singh, Karam B.; Manners, John M.; Taylor, Jennifer M.

    2015-01-01

    Pathogens and hosts are in an ongoing arms race and genes involved in host–pathogen interactions are likely to undergo diversifying selection. Fusarium plant pathogens have evolved diverse infection strategies, but how they interact with their hosts in the biotrophic infection stage remains puzzling. To address this, we analyzed the genomes of three Fusarium plant pathogens for genes that are under diversifying selection. We found a two-speed genome structure both on the chromosome and gene group level. Diversifying selection acts strongly on the dispensable chromosomes in Fusarium oxysporum f. sp. lycopersici and on distinct core chromosome regions in Fusarium graminearum, all of which have associations with virulence. Members of two gene groups evolve rapidly, namely those that encode proteins with an N-terminal [SG]-P-C-[KR]-P sequence motif and proteins that are conserved predominantly in pathogens. Specifically, 29 F. graminearum genes are rapidly evolving, in planta induced and encode secreted proteins, strongly pointing toward effector function. In summary, diversifying selection in Fusarium is strongly reflected as genomic footprints and can be used to predict a small gene set likely to be involved in host–pathogen interactions for experimental verification. PMID:25994930

  1. Phase space analysis of some interacting Chaplygin gas models

    Energy Technology Data Exchange (ETDEWEB)

    Khurshudyan, M. [Academy of Sciences of Armenia, Institute for Physical Research, Ashtarak (Armenia); Tomsk State University of Control Systems and Radioelectronics, Laboratory for Theoretical Cosmology, Tomsk (Russian Federation); Tomsk State Pedagogical University, Department of Theoretical Physics, Tomsk (Russian Federation); Myrzakulov, R. [Eurasian National University, Eurasian International Center for Theoretical Physics, Astana (Kazakhstan)

    2017-02-15

    In this paper we discuss a phase space analysis of various interacting Chaplygin gas models in general relativity. Linear and nonlinear sign changeable interactions are considered. For each case appropriate late time attractors of field equations are found. The Chaplygin gas is one of the dark fluids actively considered in modern cosmology due to the fact that it is a joint model of dark energy and dark matter. (orig.)

  2. Analysis of gas and vaporizable compounds

    International Nuclear Information System (INIS)

    Linares, Bernard; Massot, Roger; Maman, Marcel; Valdener, Georges

    1975-01-01

    The principles of qualitative and quantitative analysis using a mass spectrometer are presented together with the principle of identification of organic molecules (relation between the mass spectrum and the structure of an organic molecule. (55 references) [fr

  3. Greenhouse gas emission measurement and economic analysis of Iran natural gas fired power plants

    International Nuclear Information System (INIS)

    Shahsavari Alavijeh, H.; Kiyoumarsioskouei, A.; Asheri, M.H.; Naemi, S.; Shahsavari Alavije, H.; Basirat Tabrizi, H.

    2013-01-01

    This study attempts to examine the natural gas fired power plants in Iran. The required data from natural gas fired power plants were gathered during 2008. The characteristics of thirty two gas turbine power plants and twenty steam power plants have been measured. Their emission factor values were then compared with the standards of Energy Protection Agency, Euro Union and World Bank. Emission factors of gas turbine and steam power plants show that gas turbine power plants have a better performance than steam power plants. For economic analysis, fuel consumption and environmental damages caused by the emitted pollutants are considered as cost functions; and electricity sales revenue are taken as benefit functions. All of these functions have been obtained according to the capacity factor. Total revenue functions show that gas turbine and steam power plants are economically efficient at 98.15% and 90.89% of capacity factor, respectively; this indicates that long operating years of power plants leads to reduction of optimum capacity factor. The stated method could be implemented to assess the economic status of a country’s power plants where as efficient capacity factor close to one means that power plant works in much better condition. - Highlights: • CO 2 and NO x emissions of Iran natural gas fired power plants have been studied. • CO 2 and NO x emission factors are compared with EPA, EU and World Bank standards. • Costs and benefit as economic functions are obtained according to capacity factor. • Maximum economic profit is obtained for gas turbine and steam power plants. • Investment in CO 2 reduction is recommended instead of investment in NO x reduction

  4. The Energy Conversion Analysis of HTR Gas Turbine System

    International Nuclear Information System (INIS)

    Utaja

    2000-01-01

    The energy conversion analysis of HTR gas turbine system by hand calculation is tedious work and need much time. This difficulty comes from the repeated thermodynamic process calculation, both on compression or expansion of the cycle. To make the analysis faster and wider variable analyzed, HTR-1 programme is used. In this paper, the energy conversion analysis of HTR gas turbine system by HTR-1 will be described. The result is displayed as efficiency curve and block diagram with the input and output temperature of the component. This HTR-1 programme is developed by Basic language programming and be compiled by Visual Basic 5.0 . By this HTR-1 programme, the efficiency, specific power and effective compression of the amount of gas can be recognized fast. For example, for CO 2 gas between 40 o C and 700 o C, the compression on maximum efficiency is 4.6 and the energy specific is 18.9 kcal/kg, while the temperature changing on input and output of the component can be traced on monitor. This process take less than one second, while the manual calculation take more than one hour. It can be concluded, that the energy conversion analysis of the HTR gas turbine system by HTR-1 can be done faster and more variable analyzed. (author)

  5. Greenhouse gas and energy analysis of substitute natural gas from biomass for space heat

    International Nuclear Information System (INIS)

    Pucker, Johanna; Zwart, Robin; Jungmeier, Gerfried

    2012-01-01

    In this paper, the greenhouse gas and energy balances of the production and use for space heating of substitute natural gas from biomass (bio-SNG) for space heat are analysed. These balances are compared to the use of natural gas and solid biomass as wood chips to provide the same service. The reduction of the greenhouse gas emissions (CO 2 -eq.) – carbon dioxide, methane and nitrous oxide – and of the fossil primary energy use is investigated in a life cycle assessment (LCA). This assessment was performed for nine systems for bio-SNG; three types of gasification technologies (O 2 -blown entrained flow, O 2 -blown circulating fluidised bed and air–steam indirect gasification) with three different types of feedstock (forest residues, miscanthus and short rotation forestry). The greenhouse gas analysis shows that forest residues using the air–steam indirect gasification technology result in the lowest greenhouse gas emissions (in CO 2 -eq. 32 kg MWh −1 of heat output). This combination results in 80% reduction of greenhouse gas emissions when compared to natural gas and a 29% reduction of greenhouse gases if the forest residues were converted to wood chips and combusted. The gasification technologies O 2 -blown entrained flow and O 2 -blown circulating fluidised bed gasification have higher greenhouse gas emissions that range between in CO 2 -eq. 41 to 75 kg MWh −1 of heat output depending on the feedstock. When comparing feedstocks in the bio-SNG systems, miscanthus had the highest greenhouse gas emissions bio-SNG systems producing in CO 2 -eq. 57–75 kg MWh −1 of heat output. Energy analysis shows that the total primary energy use is higher for bio-SNG systems (1.59–2.13 MWh MWh −1 of heat output) than for the reference systems (in 1.37–1.51 MWh MWh −1 of heat output). However, with bio-SNG the fossil primary energy consumption is reduced compared to natural gas. For example, fossil primary energy use is reduced by 92% when air

  6. Thermodynamic analysis of steam-injected advanced gas turbine cycles

    Science.gov (United States)

    Pandey, Devendra; Bade, Mukund H.

    2017-12-01

    This paper deals with thermodynamic analysis of steam-injected gas turbine (STIGT) cycle. To analyse the thermodynamic performance of steam-injected gas turbine (STIGT) cycles, a methodology based on pinch analysis is proposed. This graphical methodology is a systematic approach proposed for a selection of gas turbine with steam injection. The developed graphs are useful for selection of steam-injected gas turbine (STIGT) for optimal operation of it and helps designer to take appropriate decision. The selection of steam-injected gas turbine (STIGT) cycle can be done either at minimum steam ratio (ratio of mass flow rate of steam to air) with maximum efficiency or at maximum steam ratio with maximum net work conditions based on the objective of plants designer. Operating the steam injection based advanced gas turbine plant at minimum steam ratio improves efficiency, resulting in reduction of pollution caused by the emission of flue gases. On the other hand, operating plant at maximum steam ratio can result in maximum work output and hence higher available power.

  7. Establishment of analysis method for methane detection by gas chromatography

    Science.gov (United States)

    Liu, Xinyuan; Yang, Jie; Ye, Tianyi; Han, Zeyu

    2018-02-01

    The study focused on the establishment of analysis method for methane determination by gas chromatography. Methane was detected by hydrogen flame ionization detector, and the quantitative relationship was determined by working curve of y=2041.2x+2187 with correlation coefficient of 0.9979. The relative standard deviation of 2.60-6.33% and the recovery rate of 96.36%∼105.89% were obtained during the parallel determination of standard gas. This method was not quite suitable for biogas content analysis because methane content in biogas would be over the measurement range in this method.

  8. Gas quality analysis and evaluation program for project Gasbuggy

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C F [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

    1970-05-01

    Experimental results of the gas quality analysis program for Project Gasbuggy through August 1969 are presented graphically, addressing the questions raised by the preshot program goals. The chemical composition and the concentrations of tritium, krypton-85, carbon-14 and argon-37, 39 are presented as a function of time and gas production from the nuclear chimney. Chemically, the presence of CO{sub 2}, CO and H{sub 2} served to dilute the formation gas and caused reactions which significantly altered the gas composition at early times. The radionuclide content of the chimney gas at reentry was some 800 pCi/cm{sup 3} of which about 80% was CH{sub 3}T. Lesser quantities of tritium were observed as HT, C{sub 2}H{sub 5}T and C{sub 3}H{sub 7}T. The other major contaminant was Kr{sup 85} which was present at about one-fifth the level of CH{sub 3}T. Small quantities of carbon-14 and argon-39 were also identified. The only other radionuclides identified in the gas were relatively short-lived rare gases. During the production testing, about two and one-half chimney volumes of gas at formation pressure were removed. This removal, accompanied by dilution, has reduced the radionuclide concentrations to about 7% of their levels at reentry. The production characteristics of the Gasbuggy environment prevented an adequate test of the effectiveness of chimney flushing. However, the rapid drawdown concept is supported by the available data as an effective means of reducing contaminant levels. The changes in composition during production or testing are seen to be consistent with a model involving a non-uniform gas influx rate and flow distribution over the chimney region. Mixing times are estimated to be on the order of a few days, so that increasing concentrations following a sudden gas influx can be explained. (author)

  9. Minimal Residual Disease Detection and Evolved IGH Clones Analysis in Acute B Lymphoblastic Leukemia Using IGH Deep Sequencing.

    Science.gov (United States)

    Wu, Jinghua; Jia, Shan; Wang, Changxi; Zhang, Wei; Liu, Sixi; Zeng, Xiaojing; Mai, Huirong; Yuan, Xiuli; Du, Yuanping; Wang, Xiaodong; Hong, Xueyu; Li, Xuemei; Wen, Feiqiu; Xu, Xun; Pan, Jianhua; Li, Changgang; Liu, Xiao

    2016-01-01

    Acute B lymphoblastic leukemia (B-ALL) is one of the most common types of childhood cancer worldwide and chemotherapy is the main treatment approach. Despite good response rates to chemotherapy regiments, many patients eventually relapse and minimal residual disease (MRD) is the leading risk factor for relapse. The evolution of leukemic clones during disease development and treatment may have clinical significance. In this study, we performed immunoglobulin heavy chain ( IGH ) repertoire high throughput sequencing (HTS) on the diagnostic and post-treatment samples of 51 pediatric B-ALL patients. We identified leukemic IGH clones in 92.2% of the diagnostic samples and nearly half of the patients were polyclonal. About one-third of the leukemic clones have correct open reading frame in the complementarity determining region 3 (CDR3) of IGH , which demonstrates that the leukemic B cells were in the early developmental stage. We also demonstrated the higher sensitivity of HTS in MRD detection and investigated the clinical value of using peripheral blood in MRD detection and monitoring the clonal IGH evolution. In addition, we found leukemic clones were extensively undergoing continuous clonal IGH evolution by variable gene replacement. Dynamic frequency change and newly emerged evolved IGH clones were identified upon the pressure of chemotherapy. In summary, we confirmed the high sensitivity and universal applicability of HTS in MRD detection. We also reported the ubiquitous evolved IGH clones in B-ALL samples and their response to chemotherapy during treatment.

  10. Considering the Role of Natural Gas in the Deep Decarbonization of the U.S. Electricity Sector. Natural Gas and the Evolving U.S. Power Sector Monograph Series: Number 2

    Energy Technology Data Exchange (ETDEWEB)

    Cole, Wesley [National Renewable Energy Lab. (NREL), Golden, CO (United States); Beppler, Ross [National Renewable Energy Lab. (NREL), Golden, CO (United States); Zinaman, Owen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Logan, Jeffrey [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-02-12

    Natural gas generation in the U.S. electricity sector has grown substantially in recent years, while the sector's carbon dioxide (CO2) emissions have generally declined. This relationship highlights the concept of natural gas as a potential enabler of a transition to a lower-carbon future. This work considers that concept by using the National Renewable Energy Laboratory (NREL) Renewable Energy Deployment System (ReEDS) model. ReEDS is a long-term capacity expansion model of the U.S. electricity sector. We examine the role of natural gas within the ReEDS modeling framework as increasingly strict carbon emission targets are imposed on the electricity sector. In addition to various natural gas price futures, we also consider scenarios that emphasize a low-carbon technology in order to better understand the role of natural gas if that low-carbon technology shows particular promise. Specifically, we consider scenarios with high amounts of energy efficiency (EE), low nuclear power costs, low renewable energy (RE) costs, and low carbon capture and storage (CCS) costs. Within these scenarios we find that requiring the electricity sector to lower CO2 emissions over time increases near-to-mid-term (through 2030) natural gas generation (see Figure 1 - left). The long-term (2050) role of natural gas generation in the electricity sector is dependent on the level of CO2 emission reduction required. Moderate reductions in long-term CO2 emissions have relatively little impact on long-term natural gas generation, while more stringent CO2 emission limits lower long-term natural gas generation (see Figure 1 - right). More stringent carbon targets also impact other generating technologies, with the scenarios considered here seeing significant decreases in coal generation, and new capacity of nuclear and renewable energy technologies over time. Figure 1 also demonstrates the role of natural gas in the context of scenarios where a specific low-carbon technology is advantaged. In

  11. DUST PROPERTIES AND DISK STRUCTURE OF EVOLVED PROTOPLANETARY DISKS IN Cep OB2: GRAIN GROWTH, SETTLING, GAS AND DUST MASS, AND INSIDE-OUT EVOLUTION

    International Nuclear Information System (INIS)

    Sicilia-Aguilar, Aurora; Henning, Thomas; Dullemond, Cornelis P.; Bouwman, Jeroen; Sturm, Bernhard; Patel, Nimesh; Juhász, Attila

    2011-01-01

    We present Spitzer/Infrared Spectrograph spectra of 31 T Tauri stars (TTS) and IRAM/1.3 mm observations for 34 low- and intermediate-mass stars in the Cep OB2 region. Including our previously published data, we analyze 56 TTS and 3 intermediate-mass stars with silicate features in Tr 37 (∼4 Myr) and NGC 7160 (∼12 Myr). The silicate emission features are well reproduced with a mixture of amorphous (with olivine, forsterite, and silica stoichiometry) and crystalline grains (forsterite, enstatite). We explore grain size and disk structure using radiative transfer disk models, finding that most objects have suffered substantial evolution (grain growth, settling). About half of the disks show inside-out evolution, with either dust-cleared inner holes or a radially dependent dust distribution, typically with larger grains and more settling in the innermost disk. The typical strong silicate features nevertheless require the presence of small dust grains, and could be explained by differential settling according to grain size, anomalous dust distributions, and/or optically thin dust populations within disk gaps. M-type stars tend to have weaker silicate emission and steeper spectral energy distributions than K-type objects. The inferred low dust masses are in a strong contrast with the relatively high gas accretion rates, suggesting global grain growth and/or an anomalous gas-to-dust ratio. Transition disks in the Cep OB2 region display strongly processed grains, suggesting that they are dominated by dust evolution and settling. Finally, the presence of rare but remarkable disks with strong accretion at old ages reveals that some very massive disks may still survive to grain growth, gravitational instabilities, and planet formation.

  12. Exergy analysis of a gas-hydrate cool storage system

    International Nuclear Information System (INIS)

    Bi, Yuehong; Liu, Xiao; Jiang, Minghe

    2014-01-01

    Based on exergy analysis of charging and discharging processes in a gas-hydrate cool storage system, the formulas for exergy efficiency at the sensible heat transfer stage and the phase change stage corresponding to gas-hydrate charging and discharging processes are obtained. Furthermore, the overall exergy efficiency expressions of charging, discharging processes and the thermodynamic cycle of the gas-hydrate cool storage system are obtained. By using the above expressions, the effects of number of transfer units, the inlet temperatures of the cooling medium and the heating medium on exergy efficiencies of the gas-hydrate cool storage system are emphatically analyzed. The research results can be directly used to evaluate the performance of gas-hydrate cool storage systems and design more efficient energy systems by reducing the sources of inefficiency in gas-hydrate cool storage systems. - Highlights: • Formulas for exergy efficiency at four stages are obtained. • Exergy efficiency expressions of two processes and one cycle are obtained. • Three mainly influencing factors on exergy efficiencies are analyzed. • With increasing the inlet temperature of cooling medium, exergy efficiency increases. • With decreasing the inlet temperature of heating medium, exergy efficiency increases

  13. High sensitivity analysis of atmospheric gas elements

    International Nuclear Information System (INIS)

    Miwa, Shiro; Nomachi, Ichiro; Kitajima, Hideo

    2006-01-01

    We have investigated the detection limit of H, C and O in Si, GaAs and InP using a Cameca IMS-4f instrument equipped with a modified vacuum system to improve the detection limit with a lower sputtering rate We found that the detection limits for H, O and C are improved by employing a primary ion bombardment before the analysis. Background levels of 1 x 10 17 atoms/cm 3 for H, of 3 x 10 16 atoms/cm 3 for C and of 2 x 10 16 atoms/cm 3 for O could be achieved in silicon with a sputtering rate of 2 nm/s after a primary ion bombardment for 160 h. We also found that the use of a 20 K He cryo-panel near the sample holder was effective for obtaining better detection limits in a shorter time, although the final detection limits using the panel are identical to those achieved without it

  14. High sensitivity analysis of atmospheric gas elements

    Energy Technology Data Exchange (ETDEWEB)

    Miwa, Shiro [Materials Analysis Lab., Sony Corporation, 4-16-1 Okata, Atsugi 243-0021 (Japan)]. E-mail: Shiro.Miwa@jp.sony.com; Nomachi, Ichiro [Materials Analysis Lab., Sony Corporation, 4-16-1 Okata, Atsugi 243-0021 (Japan); Kitajima, Hideo [Nanotechnos Corp., 5-4-30 Nishihashimoto, Sagamihara 229-1131 (Japan)

    2006-07-30

    We have investigated the detection limit of H, C and O in Si, GaAs and InP using a Cameca IMS-4f instrument equipped with a modified vacuum system to improve the detection limit with a lower sputtering rate We found that the detection limits for H, O and C are improved by employing a primary ion bombardment before the analysis. Background levels of 1 x 10{sup 17} atoms/cm{sup 3} for H, of 3 x 10{sup 16} atoms/cm{sup 3} for C and of 2 x 10{sup 16} atoms/cm{sup 3} for O could be achieved in silicon with a sputtering rate of 2 nm/s after a primary ion bombardment for 160 h. We also found that the use of a 20 K He cryo-panel near the sample holder was effective for obtaining better detection limits in a shorter time, although the final detection limits using the panel are identical to those achieved without it.

  15. Gas-cooled reactor safety and accident analysis

    International Nuclear Information System (INIS)

    1985-12-01

    The Specialists' Meeting on Gas-Cooled Reactor Safety and Accident Analysis was convened by the International Atomic Energy Agency in Oak Ridge on the invitation of the Department of Energy in Washington, USA. The meeting was hosted by the Oak Ridge National Laboratory. The purpose of the meeting was to provide an opportunity to compare and discuss results of safety and accident analysis of gas-cooled reactors under development, construction or in operation, to review their lay-out, design, and their operational performance, and to identify areas in which additional research and development are needed. The meeting emphasized the high safety margins of gas-cooled reactors and gave particular attention to the inherent safety features of small reactor units. The meeting was subdivided into four technical sessions: Safety and Related Experience with Operating Gas-Cooled Reactors (4 papers); Risk and Safety Analysis (11 papers); Accident Analysis (9 papers); Miscellaneous Related Topics (5 papers). A separate abstract was prepared for each of these papers

  16. Gas Chromatographic-Mass Spectrometric Analysis of Essential Oil ...

    African Journals Online (AJOL)

    Purpose: To analyze the essential oil composition of the flower of Jasminum officinale L. var. grandifloroum L. (Jasminum grandiflorum) by gas chromatography-mass spectrometry (GC-MS). Methods: The optimum GC-MS conditions used for the analysis were 250 oC inlet temperature, 150 oC MSD detector temperature, ...

  17. Gas chromatographic column for the Viking 1975 molecular analysis experiment

    Science.gov (United States)

    Novotny, M.; Hayes, J. M.; Bruner, F.; Simmonds, P. G.

    1975-01-01

    A gas chromatographic column has been developed for use in the remote analysis of the Martian surface. The column, which utilizes a liquid-modified organic adsorbent (Tenax) as the stationary phase, provides efficient transmission and resolution of nanogram quantities of organic materials in the presence of millionfold excesses of water and carbon dioxide.

  18. Analysis of gas turbine systems for sustainable energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Anheden, Marie

    2000-02-01

    Increased energy demands and fear of global warming due to the emission of greenhouse gases call for development of new efficient power generation systems with low or no carbon dioxide (CO{sub 2}) emissions. In this thesis, two different gas turbine power generation systems, which are designed with these issues in mind, are theoretically investigated and analyzed. In the first gas turbine system, the fuel is combusted using a metal oxide as an oxidant instead of oxygen in the air. This process is known as Chemical Looping Combustion (CLC). CLC is claimed to decrease combustion exergy destruction and increase the power generation efficiency. Another advantage is the possibility to separate CO{sub 2} without a costly and energy demanding gas separation process. The system analysis presented includes computer-based simulations of CLC gas turbine systems with different metal oxides as oxygen carriers and different fuels. An exergy analysis comparing the exergy destruction of the gas turbine system with CLC and conventional combustion is also presented. The results show that it is theoretically possible to increase the power generation efficiency of a simple gas turbine system by introducing CLC. A combined gas/steam turbine cycle system with CLC is, however, estimated to reach a similar efficiency as the conventional combined cycle system. If the benefit of easy and energy-efficient CO{sub 2} separation is accounted for, a CLC combined cycle system has a potential to be favorable compared to a combined cycle system with CO{sub 2} separation. In the second investigation, a solid, CO{sub 2}-neutral biomass fuel is used in a small-scale externally fired gas turbine system for cogeneration of power and district heating. Both open and closed gas turbines with different working fluids are simulated and analyzed regarding thermodynamic performance, equipment size, and economics. The results show that it is possible to reach high power generation efficiency and total (power

  19. Robustness to Faults Promotes Evolvability: Insights from Evolving Digital Circuits.

    Science.gov (United States)

    Milano, Nicola; Nolfi, Stefano

    2016-01-01

    We demonstrate how the need to cope with operational faults enables evolving circuits to find more fit solutions. The analysis of the results obtained in different experimental conditions indicates that, in absence of faults, evolution tends to select circuits that are small and have low phenotypic variability and evolvability. The need to face operation faults, instead, drives evolution toward the selection of larger circuits that are truly robust with respect to genetic variations and that have a greater level of phenotypic variability and evolvability. Overall our results indicate that the need to cope with operation faults leads to the selection of circuits that have a greater probability to generate better circuits as a result of genetic variation with respect to a control condition in which circuits are not subjected to faults.

  20. Static Structural and Modal Analysis of Gas Turbine Blade

    Science.gov (United States)

    Ranjan Kumar, Ravi; Pandey, K. M., Prof.

    2017-08-01

    Gas turbine is one of the most versatile items of turbo machinery nowadays. It is used in different modes such as power generation, oil and gas, process plants, aviation, domestic and related small industries. This paper is based on the problems concerning blade profile selection, material selection and turbine rotor blade vibration that seriously impact the induced stress-deformation and structural functioning of developmental gas turbine engine. In this paper for generating specific power by rotating blade at specific RPM, blade profile and material has been decided by static structural analysis. Gas turbine rotating blade RPM is decided by Modal Analysis so that the natural frequency of blade should not match with the excitation frequency. For the above blade profile has been modeled in SOLIDWORKS and analysis has been done in ANSYS WORKBENCH 14. Existing NACA6409 profile has been selected as base model and then it is modified by bending it through 72.5° and 145°. Hence these three different blade profiles have been analyzed for three different materials viz. Super Alloy X, Nimonic 80A and Inconel 625 at three different speed viz. 20000, 40000 and 60000RPM. It is found that NACA6409 with 72.5° bent gives best result for all material at all speed. Among all the material Inconel 625 gives best result. Hence Blade of Inconel 625 having 72.5° bent profile is the best combination for all RPM.

  1. Certain questions about analysis of natural gas disolved in brine

    Energy Technology Data Exchange (ETDEWEB)

    Tezuka, M; Nakamura, M; Omi, K

    1983-01-01

    The composition of the gaseous phase of stratum brines is determined and the analysis technique is described. Ordinary analysis is performed with the assumptions that the contents of small components (excluding C02 and N2) are ignorably small and that the gas contains no 02. The determined concentrations of 02 and the proportional share of N2 are calculated from results of analysis as bound with pollutants. The high sensitivity of modern analytical methods makes it possible to identify quite small and trace concentrations of components, but corrections for air contamination may partially depreciate these results. Data are cited from gas chromatographic identifications of the components of gases disolved in the stratum brines of a Japanese deposit. C2H6 is established in all samples and C3H8 in two thirds of the samples, where H2 and helium were not detected anywhere. The concentrations of the gas phase on the whole in the brine were low. 02 falls into the samples in a water dissolved state; this demands the use of unconventional proportion of 02 to N2 (1 to 3.55), which is characteristic for air and a proportion of 1 to 2 which is characteristic for disolved air. With the conventional ordinary technique the consideration of the air contamination leads to a substantial underestimate of the N2 results. At the same time, the incorrect introduction of corrections for N2 has no effect on the heat creativity of the disolved gas.

  2. Geospatial Analysis of Oil and Gas Wells in California

    Science.gov (United States)

    Riqueros, N. S.; Kang, M.; Jackson, R. B.

    2015-12-01

    California currently ranks third in oil production by U.S. state and more than 200,000 wells have been drilled in the state. Oil and gas wells provide a potential pathway for subsurface migration, leading to groundwater contamination and emissions of methane and other fluids to the atmosphere. Here we compile available public databases on oil and gas wells from the California Department of Conservation's Division of Oil, Gas, and Geothermal Resources, the U.S. Geological Survey, and other state and federal sources. We perform geospatial analysis at the county and field levels to characterize depths, producing formations, spud/completion/abandonment dates, land cover, population, and land ownership of active, idle, buried, abandoned, and plugged wells in California. The compiled database is designed to serve as a quantitative platform for developing field-based groundwater and air emission monitoring plans.

  3. PIXE analysis of exhaust gas from diesel engine

    International Nuclear Information System (INIS)

    Miyake, Hirosi; Michijima, Masami; Onishi, Masayuki; Fujitani, Tatsuya.

    1986-01-01

    The variation of elemental concentrations in exhaust gas of a Diesel engine with the outputs was studied. Particulates in high temperature gas were collected on silica fiber filters and analyzed by PIXE method. Concentrations of S and V were nearly proportional to particulate masses and fuel consumption rates per discharging rates of exhaust gas respectively. While, concentrations of Fe and Mn were markedly increased together with engine outputs, and Mn/Fe ratios were nearly equal to those of the material of piston rings and the cylinder liner. Concentrations of the elements contained in lubricant, such as Ca and Mo, were also conspicuously increased with the outputs. It was shown that PIXE analysis is a useful tool for engine diagonostics owing to its high sensitive multi-elemental availability without chemical treatments. (author)

  4. Exergy analysis of gas turbine with air bottoming cycle

    International Nuclear Information System (INIS)

    Ghazikhani, M.; Khazaee, I.; Abdekhodaie, E.

    2014-01-01

    In this paper, the exergy analysis of a conventional gas turbine and a gas turbine with air bottoming cycle (ABC) is presented in order to study the important parameters involved in improving the performance characteristics of the ABC based on the Second Law of thermodynamics. In this study, work output, specific fuel consumption (SFC) and the exergy destruction of the components are investigated using a computer model. The variations of the ABC cycle exergy parameters are comprehensively discussed and compared with those of the simple gas turbine. The results indicate that the amount of the exhaust exergy recovery in different operating conditions varies between 8.6 and 14.1% of the fuel exergy, while the exergy destruction due to the extra components in the ABC makes up only 4.7–7.4% of the fuel exergy. This is the reason why the SFC of the ABC is averagely 13.3% less and the specific work 15.4% more than those of the simple gas turbine. The results also reveal that in the ABC cycle, at a small value of pressure ratio, a higher specific work with lower SFC can be achieved in comparison with those of the simple gas turbine. - Highlights: • Exhaust exergy recovery in ABC gas turbine varies with 8.6–14.1% of the fuel exergy. • Irreversibility of the extra devices in ABC makes up 4.7–7.4% of the fuel exergy. • SFC in ABC is poor due to exergy recovery more than extra devices irreversibility. • At the same TIT and R c , specific work in the ABC is more than simple gas turbine. • The recuperator has the largest contribution in the irreversibility of the ABC

  5. An Analysis of Quality of Service (QoS In Live Video Streaming Using Evolved HSPA Network Media

    Directory of Open Access Journals (Sweden)

    Achmad Zakaria Azhar

    2016-10-01

    Full Text Available Evolved High Speed Packet Access (HSPA+ is a mobile telecommunication system technology and the evolution of HSPA technology. This technology has a packet data based service with downlink speeds up to 21.1 Mbps and uplink speed up to 11.5 Mbps on the bandwidth 5MHz. This technology is expected to fulfill and support the needs for information that involves all aspects of multimedia such as video and audio, especially live video streaming. By utilizing this technology it will facilitate communicating the information, for example to monitoring the situation of the house, the news coverage at some certain area, and other events in real time. This thesis aims to identify and test the Quality of Service (QoS performance on the network that is used for live video streaming with the parameters of throughput, delay, jitter and packet loss. The software used for monitoring the data traffic of the live video streaming network is wireshark network analyzer. From the test results it is obtained that the average throughput of provider B is 5,295 Kbps bigger than the provider A, the average delay of provider B is 0.618 ms smaller than the provider A, the average jitter of provider B is 0.420 ms smaller than the provider A and the average packet loss of provider B is 0.451% smaller than the provider A.

  6. Evolving Information Needs among Colon, Breast, and Prostate Cancer Survivors: Results from a Longitudinal Mixed-Effects Analysis.

    Science.gov (United States)

    Tan, Andy S L; Nagler, Rebekah H; Hornik, Robert C; DeMichele, Angela

    2015-07-01

    This study describes how cancer survivors' information needs about recurrence, late effects, and family risks of cancer evolve over the course of their survivorship period. Three annual surveys were conducted from 2006 to 2008 in a cohort of Pennsylvania cancer survivors diagnosed with colon, breast, or prostate cancer in 2005 (round 1, N = 2,013; round 2, N = 1,293; round 3, N = 1,128). Outcomes were information seeking about five survivorship topics. Key predictors were survey round, cancer diagnosis, and the interaction between these variables. Mixed-effects logistic regression analyses were performed to predict information seeking about each topic, adjusting for demographic variables, clinical characteristics, and clustering of repeated observations within individuals. Information seeking about reducing risks of cancer recurrence was the most frequently reported topic across survivors and over time. Breast cancer survivors were more likely to seek about survivorship topics at round 1 compared with other survivors. In general, information seeking declined over time, but cancer-specific patterns emerged: the decline was sharpest for breast cancer survivors, whereas in later years female colon cancer survivors actually sought more information (about how to reduce the risk of family members getting colon cancer or a different cancer). Cancer survivors' information needs varied over time depending on the topic, and these trends differed by cancer type. Clinicians may need to intervene at distinct points during the survivorship period with information to address concerns about cancer recurrence, late effects, and family members' risks. ©2015 American Association for Cancer Research.

  7. System analysis and planning of a gas distribution network

    Energy Technology Data Exchange (ETDEWEB)

    Salas, Edwin F.M.; Farias, Helio Monteiro [AUTOMIND, Rio de Janeiro, RJ (Brazil); Costa, Carla V.R. [Universidade Salvador (UNIFACS), BA (Brazil)

    2009-07-01

    The increase in demand by gas consumers require that projects or improvements in gas distribution networks be made carefully and safely to ensure a continuous, efficient and economical supply. Gas distribution companies must ensure that the networks and equipment involved are defined and designed at the appropriate time to attend to the demands of the market. To do that a gas distribution network analysis and planning tool should use distribution networks and transmission models for the current situation and the future changes to be implemented. These models are used to evaluate project options and help in making appropriate decisions in order to minimize the capital investment in new components or simple changes in operational procedures. Gas demands are increasing and it is important that gas distribute design new distribution systems to ensure this growth, considering financial constraints of the company, as well as local legislation and regulation. In this study some steps of developing a flexible system that attends to those needs will be described. The analysis of distribution requires geographically referenced data for the models as well as an accurate connectivity and the attributes of the equipment. GIS systems are often used as a deposit center that holds the majority of this information. GIS systems are constantly updated as distribution network equipment is modified. The distribution network modeling gathered from this system ensures that the model represents the current network condition. The benefits of this architecture drastically reduce the creation and maintenance cost of the network models, because network components data are conveniently made available to populate the distribution network. This architecture ensures that the models are continually reflecting the reality of the distribution network. (author)

  8. Economic Impacts Analysis of Shale Gas Investment in China

    Science.gov (United States)

    Han, Shangfeng; Zhang, Baosheng; Wang, Xuecheng

    2018-01-01

    Chinese government has announced an ambitious shale gas extraction plan, which requires significant investment. This has the potential to draw investment from other areas and may affect the whole China’s economy. There is few study to date has quantified these shale gas investment’s effects on Chinese economy. The aim of this paper is to quantify the economic effect and figures out whether shale gas investment in China is a good choice or not. Input-output analysis has been utilized in this study to estimate the economic impacts in four different Chinese regions. Our findings show that shale gas investment will result in approximately 868, 427, 115 and 42 Billion RMB economic impacts in Sichuan, Chongqing, Inner Mongolia and Guizhou, respectively. The total economic impact is only around 1453 Billion RMB, which is not significant compared to the economic impact of coalbed methane investment. Considering the potential risks of environmental issues, we suggest that it may be a better strategy for the government, at least in the current situation, to slow down shale gas development investment.

  9. Hazards analysis of TNX Large Melter-Off-Gas System

    International Nuclear Information System (INIS)

    Randall, C.T.

    1982-03-01

    Analysis of the potential safety hazards and an evaluation of the engineered safety features and administrative controls indicate that the LMOG System can be operated without undue hazard to employees or the public, or damage to equipment. The safety features provided in the facility design coupled with the planned procedural and administrative controls make the occurrence of serious accidents very improbable. A set of recommendations evolved during this analysis that was judged potentially capable of further reducing the probability of personnel injury or further mitigating the consequences of potential accidents. These recommendations concerned areas such as formic acid vapor hazards, hazard of feeding water to the melter at an uncontrolled rate, prevention of uncontrolled glass pours due to melter pressure excursions and additional interlocks. These specific suggestions were reviewed with operational and technical personnel and are being incorporated into the process. The safeguards provided by these recommendations are discussed in this report

  10. Population level analysis of evolved mutations underlying improvements in plant hemicellulose and cellulose fermentation by Clostridium phytofermentans.

    Directory of Open Access Journals (Sweden)

    Supratim Mukherjee

    Full Text Available The complexity of plant cell walls creates many challenges for microbial decomposition. Clostridium phytofermentans, an anaerobic bacterium isolated from forest soil, directly breaks down and utilizes many plant cell wall carbohydrates. The objective of this research is to understand constraints on rates of plant decomposition by Clostridium phytofermentans and identify molecular mechanisms that may overcome these limitations.Experimental evolution via repeated serial transfers during exponential growth was used to select for C. phytofermentans genotypes that grow more rapidly on cellobiose, cellulose and xylan. To identify the underlying mutations an average of 13,600,000 paired-end reads were generated per population resulting in ∼300 fold coverage of each site in the genome. Mutations with allele frequencies of 5% or greater could be identified with statistical confidence. Many mutations are in carbohydrate-related genes including the promoter regions of glycoside hydrolases and amino acid substitutions in ABC transport proteins involved in carbohydrate uptake, signal transduction sensors that detect specific carbohydrates, proteins that affect the export of extracellular enzymes, and regulators of unknown specificity. Structural modeling of the ABC transporter complex proteins suggests that mutations in these genes may alter the recognition of carbohydrates by substrate-binding proteins and communication between the intercellular face of the transmembrane and the ATPase binding proteins.Experimental evolution was effective in identifying molecular constraints on the rate of hemicellulose and cellulose fermentation and selected for putative gain of function mutations that do not typically appear in traditional molecular genetic screens. The results reveal new strategies for evolving and engineering microorganisms for faster growth on plant carbohydrates.

  11. Possibilities of gas-phase radio-chromatography application to permanent-gas analysis

    International Nuclear Information System (INIS)

    Dupuis, M.C.; Charrier, G.; Alba, C.; Massimino, D.

    1970-01-01

    The gas-phase radio-chromatography technique has been applied to the rapid analysis of permanent gases (H 2 , O 2 , N 2 , A, Kr, Xe, CO, CH 4 ) labelled with radioactive indicators ( 3 H, 37 A, 85 Kr, 133 Xe). After calibration, the components of such a mixture can be identified and their concentrations measured in less than two hours, using a sample volume of from 0.1 to 10 cm 3 . The minimum detectable activity is of the order of 10 -4 μC for each radioactive isotope. The measurements are reproducible to about 2 to 3 per cent. This work has been mainly concerned with the influence of parameters affecting the response of the radioactivity detector (ionization chamber or gas flow proportional counter). The method has very numerous applications both theoretically, for the study of chromatographic phenomena under ideal conditions (infinitesimal concentrations made possible by the use of radioactive tracers), and practically, for rapid and accurate radiochemical analysis of radioactive gas mixtures. (authors) [fr

  12. Evolving energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Mills, E.

    1991-04-01

    This thesis presents scenarios of future energy systems, a cost-benefit analysis of measures to avoid greenhouse-gas emissions, an analysis of the effect of energy prices on end-use efficiencies and fuel choices, and an evaluation of financial-incentive programs designed to induce investments in efficient energy use. Twelve integrated energy supply/demand scenarios for the Swedish heat-and-power sector are presented to illustrate the potential for improvements in end-use efficiency and increased utilization of renewable energy sources. The results show that greenhouse-gas emissions could be reduced by 35 per cent from 1987 levels by 2010, with a net economic benefit compared to a business-as-usual scenario. A generalized methodology for calculating the net costs of reducing greenhouse-gas emissions is applied to a variety of fuel choices and energy end-use technologies. A key finding is that a combination of increased end-use efficiencies and use of renewable energy systems is required to achieve maximum cost-effective emissions reductions. End-use efficiencies and inter-fuel competition in Denmark and Sweden are compared during a time period in which real electricity prices were declining in Sweden and increasing in Denmark. Despite these different price environments, efficiencies and choices of heating fuels did not generally develop as expected according to economic theory. The influences of counter-price and non-price factors are important in understanding this outcome. Relying on prices alone injects considerable uncertainty into the energy planning process, and precludes efficiency improvements and fuel choices attainable with other mechanisms. Incentive programs can be used to promote energy-efficient technologies. Utilities in Europe have recently offered financial incentives intended to stimulate the adoption of compact-fluorescent lamps. These programs have been cost-effective in comparison to new electric supply. (au).

  13. Gas chromatographic isolation technique for compound-specific radiocarbon analysis

    International Nuclear Information System (INIS)

    Uchida, M.; Kumamoto, Y.; Shibata, Y.; Yoneda, M.; Morita, M.; Kawamura, K.

    2002-01-01

    Full text: We present here a gas chromatographic isolation technique for the compound-specific radiocarbon analysis of biomarkers from the marine sediments. The biomarkers of fatty acids, hydrocarbon and sterols were isolated with enough amount for radiocarbon analysis using a preparative capillary gas chromatograph (PCGC) system. The PCGC systems used here is composed of an HP 6890 GC with FID, a cooled injection system (CIS, Gerstel, Germany), a zero-dead-volume effluent splitter, and a cryogenic preparative collection device (PFC, Gerstel). For AMS analysis, we need to separate and recover sufficient quantity of target individual compounds (>50 μgC). Yields of target compounds from C 14 n-alkanes to C 40 to C 30 n-alkanes and approximately that of 80% for higher molecular weights compounds more than C 30 n-alkanes. Compound specific radiocarbon analysis of organic compounds, as well as compound-specific stable isotope analysis, provide valuable information on the origins and carbon cycling in marine system. Above PCGC conditions, we applied compound-specific radiocarbon analysis to the marine sediments from western north Pacific, which showed the possibility of a useful chronology tool for estimating the age of sediment using organic matter in paleoceanographic study, in the area where enough amounts of planktonic foraminifera for radiocarbon analysis by accelerator mass spectrometry (AMS) are difficult to obtain due to dissolution of calcium carbonate. (author)

  14. Infrared spectroscopy of evolved objects

    International Nuclear Information System (INIS)

    Aitken, D.K.; Roche, P.F.

    1984-01-01

    In this review, the authors are concerned with spectroscopic observations of evolved objects made in the wavelength range 1-300μm. Spectroscopic observations can conveniently be divided into studies of narrow lines, bands and broader continua. The vibrational frequencies of molecular groups fall mainly in this spectral region and appear as vibration-rotation bands from the gas phase, and as less structured, but often broader, features from the solid state. Many ionic lines, including recombination lines of abundant species and fine structure lines of astrophysically important ions also appear in this region. The continuum can arise from a number of mechanisms - photospheric emission, radiation from dust, free-free transitions in ionized gas and non-thermal processes. (Auth.)

  15. Designing and analysis study of uranium enrichment with gas centrifuge

    International Nuclear Information System (INIS)

    Tsunetoshi Kai

    2006-01-01

    This note concerns a designing and analysis study of uranium enrichment with a gas centrifuge. At first, one dimensional model is presented and a conventional analytical method is applied to grasp the general idea of a centrifuge performance. Secondly, two-dimensional numerical method is adopted to describe the diffusion phenomena with assumption of simple flow patterns. Parametric surveys are made on the dimension of a centrifuge rotor, the gas feed, withdrawal and circulation system, and operation variables such as feed flow rate, cut and so on. Thirdly, full numerical solutions are obtained for the flow and diffusion equations in static state, using a modified version of the Newton method without neglect of any non-linear term. The numerical results are compared with the experimental data made by Beams et al. and Zippe, and found to be in good agreement. Further, the theoretical pressure and separative power are compared respectively with experimental ones on a comparatively recent centrifuge. The results reveal that the characteristics of separation performance of a centrifuge can be fully described by the present method. Some of inevitable problems are tackled regarding UF 6 gas isotope separation by centrifugation. To examine the influence of the extraneous light gas, the diffusion equations for ternary mixture are solved and also the flow field of binary mixture with large mass difference is obtained to simultaneously solve the Navier-Stokes equations and the diffusion equation.for binary case. Since the gas in the interior region of the rotor is so rarefied that the Navier-Stokes equations cease to be valid, the Burnett equations are solved.for gas flow in a rotating cylinder. Considering that the uranium recovered at a reprocessing plant includes 236 U besides 235 U and 238 U, the concentration distributions of the ternary gas isotopes are determined and a value function is defined for the evaluation of separative work for the multi-component mixture

  16. Performance analysis and optimization of power plants with gas turbines

    Science.gov (United States)

    Besharati-Givi, Maryam

    The gas turbine is one of the most important applications for power generation. The purpose of this research is performance analysis and optimization of power plants by using different design systems at different operation conditions. In this research, accurate efficiency calculation and finding optimum values of efficiency for design of chiller inlet cooling and blade cooled gas turbine are investigated. This research shows how it is possible to find the optimum design for different operation conditions, like ambient temperature, relative humidity, turbine inlet temperature, and compressor pressure ratio. The simulated designs include the chiller, with varied COP and fogging cooling for a compressor. In addition, the overall thermal efficiency is improved by adding some design systems like reheat and regenerative heating. The other goal of this research focuses on the blade-cooled gas turbine for higher turbine inlet temperature, and consequently, higher efficiency. New film cooling equations, along with changing film cooling effectiveness for optimum cooling air requirement at the first-stage blades, and an internal and trailing edge cooling for the second stage, are innovated for optimal efficiency calculation. This research sets the groundwork for using the optimum value of efficiency calculation, while using inlet cooling and blade cooling designs. In the final step, the designed systems in the gas cycles are combined with a steam cycle for performance improvement.

  17. Gas Hydrate Investigations Using Pressure Core Analysis: Current Practice

    Science.gov (United States)

    Schultheiss, P.; Holland, M.; Roberts, J.; Druce, M.

    2006-12-01

    Recently there have been a number of major gas hydrate expeditions, both academic and commercially oriented, that have benefited from advances in the practice of pressure coring and pressure core analysis, especially using the HYACINTH pressure coring systems. We report on the now mature process of pressure core acquisition, pressure core handling and pressure core analysis and the results from the analysis of pressure cores, which have revealed important in situ properties along with some remarkable views of gas hydrate morphologies. Pressure coring success rates have improved as the tools have been modified and adapted for use on different drilling platforms. To ensure that pressure cores remain within the hydrate stability zone, tool deployment, recovery and on-deck handling procedures now mitigate against unwanted temperature rises. Core analysis has been integrated into the core transfer protocol and automated nondestructive measurements, including P-wave velocity, gamma density, and X-ray imaging, are routinely made on cores. Pressure cores can be subjected to controlled depressurization experiments while nondestructive measurements are being made, or cores can be stored at in situ conditions for further analysis and subsampling.

  18. Spectroscopic analysis of femtosecond laser-induced gas breakdown

    International Nuclear Information System (INIS)

    Hermann, J.; Bruneau, S.; Sentis, M.

    2004-01-01

    The plasma generated by the interaction of a femtosecond laser pulse with gas has been analyzed using time- and space-resolved emission spectroscopy. The laser beam has been focused with a microscope objective into different gases (air, Ar, He) at pressures ranging from 10 2 to 10 5 Pa. From the analysis of spectral line emission from ions and neutral atoms, the plasma parameters and the plasma composition have been determined as a function of time and space. Furthermore, the generation of fast electrons and/or VUV radiation by the femtosecond laser interaction with the gas was brought to the fore. From the time- and space-evolution of the plasma parameters, a rough estimation of initial values of electron density and refraction index in the focal volume has been performed. These results are compared to analysis of the laser beam transmitted by the plasma. The latter show that only a small fraction of the laser energy is absorbed by the plasma while the spatial distribution of the transmitted laser beam is strongly perturbed by the plasma, which acts like a defocusing lens. However, in ambient helium, the plasma defocusing is weak due to the high ionization potential of helium. The understanding of femtosecond laser-induced gas breakdown is useful for process optimization in femtosecond laser applications like micromachining or surface microanalysis, etc

  19. Analysis of Maisotsenko open gas turbine bottoming cycle

    International Nuclear Information System (INIS)

    Saghafifar, Mohammad; Gadalla, Mohamed

    2015-01-01

    Maisotsenko gas turbine cycle (MGTC) is a recently proposed humid air turbine cycle. An air saturator is employed for air heating and humidification purposes in MGTC. In this paper, MGTC is integrated as the bottoming cycle to a topping simple gas turbine as Maisotsenko bottoming cycle (MBC). A thermodynamic optimization is performed to illustrate the advantages and disadvantages of MBC as compared with air bottoming cycle (ABC). Furthermore, detailed sensitivity analysis is reported to present the effect of different operating parameters on the proposed configurations' performance. Efficiency enhancement of 3.7% is reported which results in more than 2600 tonne of natural gas fuel savings per year. - Highlights: • Developed an accurate air saturator model. • Introduced Maisotsenko bottoming cycle (MBC) as a power generation cycle. • Performed Thermodynamic optimization for MBC and air bottoming cycle (ABC). • Performed detailed sensitivity analysis for MBC under different operating conditions. • MBC has higher efficiency and specific net work output as compared to ABC

  20. Low volume sampling device for mass spectrometry analysis of gas formation in nickel-metalhydride (NiMH) batteries

    International Nuclear Information System (INIS)

    Kruesemann, P.V.E.; Mank, A.J.G.; Belfadhel-Ayeb, A.; Notten, P.H.L.

    2006-01-01

    Rechargeable nickel-metalhydride (NiMH) batteries have major advantages with respect to environmental friendliness and energy density compared to other battery systems. Research on thermodynamics and reaction kinetics is required to study the behaviour of these batteries, especially under severe operating conditions such as overcharging and (over)discharging. During these processes several reactions take place resulting in the formation of oxygen and hydrogen gas. Hence, the recombination processes should be well controlled to guarantee that the partial oxygen and hydrogen pressure inside the battery are kept low. Mass spectrometry is one of the analytical techniques capable of measuring the composition of gases released inside the battery during the charge and discharge processes. However, the sample gas needs to be withdrawn from the battery during the experiment. The gas consumption must be kept to a minimum otherwise the equilibrium inside the battery will be disturbed. A bench-top quadrupole mass spectrometer with a standard capillary by-pass inlet cannot be used for this purpose as its gas consumption is in the 1-10 ml/min range. In this paper, a new gas inlet device is presented that reduces gas consumption to a value <50 μl/h. The use of a capillary by-pass splitter and a discontinuous sampling procedure allow mass spectrometry to be used as a gas analysis tool in many applications in which small amounts of sample gas are involved. Experiments with standard AA-size NiMH batteries show that hydrogen release dominates during (over)charging at increased charging rates. Beside mass spectrometry, evolved gases are also analysed using Raman spectroscopy. Although some differences are observed, the results of similar experiments show a good agreement

  1. Commercial sector gas cooling technology frontier and market share analysis

    International Nuclear Information System (INIS)

    Pine, G.D.; Mac Donald, J.M.; McLain, H.A.

    1990-01-01

    This paper describes a method, developed for the Gas Research Institute of the United States, that can assist planning for commercial sector natural gas cooling systems R and D. These systems are higher in first cost than conventional electric chillers. Yet, engine-driven chiller designs exist which are currently competitive in U.S. markets typified by high electricity or demand charges. Section II describes a scenario analysis approach used to develop and test the method. Section III defines the technology frontier, a conceptual tool for identifying new designs with sales potential. Section IV describes a discrete choice method for predicting market shares of technologies with sales potential. Section V shows how the method predicts operating parameter, cost, and/or performance goals for technologies without current sales potential (or for enhancing a frontier technology's sales potential). Section VI concludes with an illustrative example for the Chicago office building retrofit market

  2. Startup analysis for a high temperature gas loaded heat pipe

    Science.gov (United States)

    Sockol, P. M.

    1973-01-01

    A model for the rapid startup of a high-temperature gas-loaded heat pipe is presented. A two-dimensional diffusion analysis is used to determine the rate of energy transport by the vapor between the hot and cold zones of the pipe. The vapor transport rate is then incorporated in a simple thermal model of the startup of a radiation-cooled heat pipe. Numerical results for an argon-lithium system show that radial diffusion to the cold wall can produce large vapor flow rates during a rapid startup. The results also show that startup is not initiated until the vapor pressure p sub v in the hot zone reaches a precise value proportional to the initial gas pressure p sub i. Through proper choice of p sub i, startup can be delayed until p sub v is large enough to support a heat-transfer rate sufficient to overcome a thermal load on the heat pipe.

  3. IDP camp evolvement analysis in Darfur using VHSR optical satellite image time series and scientific visualization on virtual globes

    Science.gov (United States)

    Tiede, Dirk; Lang, Stefan

    2010-11-01

    In this paper we focus on the application of transferable, object-based image analysis algorithms for dwelling extraction in a camp for internally displaced people (IDP) in Darfur, Sudan along with innovative means for scientific visualisation of the results. Three very high spatial resolution satellite images (QuickBird: 2002, 2004, 2008) were used for: (1) extracting different types of dwellings and (2) calculating and visualizing added-value products such as dwelling density and camp structure. The results were visualized on virtual globes (Google Earth and ArcGIS Explorer) revealing the analysis results (analytical 3D views,) transformed into the third dimension (z-value). Data formats depend on virtual globe software including KML/KMZ (keyhole mark-up language) and ESRI 3D shapefiles streamed as ArcGIS Server-based globe service. In addition, means for improving overall performance of automated dwelling structures using grid computing techniques are discussed using examples from a similar study.

  4. Multiplex gas chromatography: an alternative concept for gas chromatographic analysis of planetary atmospheres

    Science.gov (United States)

    Valentin, J. R.

    1989-01-01

    -Cassini entry probe, which is being jointly planned by NASA and the European Space Agency (ESA), might be launched as early as 1994. As in the Pioneer mission, limited time--perhaps only 3-4 h--will be available for the completion of all analyses while the probe descends through the atmosphere. A conventional GC or GC-MS system would be able to analyze no more than two aerosol and two gas samples during the probe's descent. Conventional GC also is limited by the sensitivity of the detector and by the sample volume. For the Titan mission, the sensitivity problems will be worse because the atmospheric pressure at the time of instrument deployment is expected to be of such limitations, alternative GC analysis techniques have been investigated for future NASA missions. Multiplex gas chromatography has been investigated as a possible candidate for chemical analysis within a spacecraft or other restricted environment, and chemical modulators have been developed and used when needed with this technique to reduce the size and weight of the instrumentation. Also, several new multiplex techniques have been developed for use in specific applications.

  5. Safety analysis of a high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Shimazu, Akira; Morimoto, Toshio

    1975-01-01

    In recent years, in order to satisfy the social requirements of environment and safety and also to cope with the current energy stringency, the installation of safe nuclear power plants is indispensable. Herein, safety analysis and evaluation to confirm quantitatively the safety design of a nuclear power plant become more and more important. The safety analysis and its methods for a high temperature gas-cooled reactor are described, with emphasis placed on the practices by Fuji Electric Manufacturing Co. Fundamental rule of securing plant safety ; safety analysis in normal operation regarding plant dynamic characteristics and radioactivity evaluation ; and safety analysis at the time of accidents regarding plant response to the accidents and radioactivity evaluation are explained. (Mori, K.)

  6. Noble Gas Measurement and Analysis Technique for Monitoring Reprocessing Facilities

    International Nuclear Information System (INIS)

    William S. Charlton

    1999-01-01

    An environmental monitoring technique using analysis of stable noble gas isotopic ratios on-stack at a reprocessing facility was developed. This technique integrates existing technologies to strengthen safeguards at reprocessing facilities. The isotopic ratios are measured using a mass spectrometry system and are compared to a database of calculated isotopic ratios using a Bayesian data analysis method to determine specific fuel parameters (e.g., burnup, fuel type, fuel age, etc.). These inferred parameters can be used by investigators to verify operator declarations. A user-friendly software application (named NOVA) was developed for the application of this technique. NOVA included a Visual Basic user interface coupling a Bayesian data analysis procedure to a reactor physics database (calculated using the Monteburns 3.01 code system). The integrated system (mass spectrometry, reactor modeling, and data analysis) was validated using on-stack measurements during the reprocessing of target fuel from a U.S. production reactor and gas samples from the processing of EBR-II fast breeder reactor driver fuel. These measurements led to an inferred burnup that matched the declared burnup with sufficient accuracy and consistency for most safeguards applications. The NOVA code was also tested using numerous light water reactor measurements from the literature. NOVA was capable of accurately determining spent fuel type, burnup, and fuel age for these experimental results. Work should continue to demonstrate the robustness of this system for production, power, and research reactor fuels

  7. Gas

    International Nuclear Information System (INIS)

    1996-01-01

    The French government has decided to modify the conditions of extension of local natural gas authorities to neighbouring districts. The European Union is studying the conditions of internal gas market with the objective of more open markets although considering public service requirements

  8. Indoor air quality inspection and analysis system based on gas sensor array

    Science.gov (United States)

    Gao, Xiang; Wang, Mingjiang; Fan, Binwen

    2017-08-01

    A detection and analysis system capable of measuring the concentration of four major gases in indoor air is designed. It uses four gas sensors constitute a gas sensor array, to achieve four indoor gas concentration detection, while the detection of data for further processing to reduce the cross-sensitivity between the gas sensor to improve the accuracy of detection.

  9. Potential application of gas chromatography to the analysis of hydrogen isotopes

    International Nuclear Information System (INIS)

    Warner, D.K.; Sprague, R.E.; Bohl, D.R.

    1976-01-01

    Gas chromatography is used at Mound Laboratory for the analysis of hydrogen isotopic impurities in gas mixtures. This instrumentation was used to study the applicability of the gas chromatography technique to the determination of the major components of hydrogen isotopic gas mixtures. The results of this study, including chromatograms and precision data, are presented

  10. Analysis of the Retained Gas Sample (RGS) Extruder Assembly

    International Nuclear Information System (INIS)

    Coverdell, B.L.

    1995-09-01

    In order for the Retained Gas Sample (RGS) Extruder Assembly to be safely used it was determined by the cognizant engineer that analysis was necessary. The use of the finite-element analysis (FEA) progarm COSMOS/M version 1.71 permitted a quick, easy, and detailed stress analysis of the RGS Extruder Assembly. The FEA model is a three dimensional model using the SHELL4T element type. From the results of the FEA, the cognizant engineer determined that the RGS extruder would be rated at 10,000 lbf and load tested to 12,000 lbf. The respective input and output files for the model are EXTR02.GFM and EXTR02.OUT and can be found on the attached tape

  11. Gas chromatographic analysis of extractive solvent in reprocessing plants

    International Nuclear Information System (INIS)

    Marlet, B.

    1984-01-01

    Operation of a reprocessing plant using the Purex process is recalled and analytical controls for optimum performance are specified. The aim of this thesis is the development of analytical methods using gas chromatography required to follow the evolution of the extraction solvent during spent fuel reprocessing. The solvent at different concentrations, is analysed along the reprocessing lines in organic or aqueous phases. Solvent degradation interferes with extraction and decomposition products are analysed. The solvent becomes less and less efficient, also it is distilled and quality is checked. Traces of solvent should also be checked in waste water. Analysis are made as simple as possible to facilitate handling of radioactive samples [fr

  12. Thermodynamic Analysis of Supplementary-Fired Gas Turbine Cycles

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Henriksen, Ulrik Birk; Qvale, Einar Bjørn

    2003-01-01

    to result in a high marginal efficiency. The paper shows that depending on the application, this is not always the case. The interest in this cycle arises from a recent demonstration of the feasibility of a two-stage gasification process through construction of several plants. The gas from this process...... could be divided into two streams, one for primary and one for supplementary firing. A preliminary analysis of the ideal, recuperated Brayton cycle shows that for this cycle any supplementary firing will have a marginal efficiency of unity per extra unit of fuel. The same result is obtained...

  13. Tag gas burnup based on three-dimensional FTR analysis

    International Nuclear Information System (INIS)

    Kidman, R.B.

    1976-01-01

    Flux spectra from a three-dimensional diffusion theory analysis of the Fast Test Reactor (FTR) are used to predict gas tag ratio changes, as a function of exposure, for each FTR fuel and absorber subassembly plenum. These flux spectra are also used to predict Xe-125 equilibrium activities in absorber plena in order to assess the feasibility of using Xe-125 gamma rays to detect and distinguish control rod failures from fuel rod failures. Worst case tag burnup changes are used in conjunction with burnup and mass spectrometer uncertainties to establish the minimum spacing of tags which allows the tags to be unambiguously identified

  14. Applications of stable isotope analysis to atmospheric trace gas budgets

    Directory of Open Access Journals (Sweden)

    Brenninkmeijer C. A.M.

    2009-02-01

    Full Text Available Stable isotope analysis has become established as a useful method for tracing the budgets of atmospheric trace gases and even atmospheric oxygen. Several new developments are briefly discussed in a systematic way to give a practical guide to the scope of recent work. Emphasis is on applications and not on instrumental developments. Processes and reactions are less considered than applications to resolve trace gas budgets. Several new developments are promising and applications hitherto not considered to be possible may allow new uses.

  15. Performance analysis of solar energy integrated with natural-gas-to-methanol process

    International Nuclear Information System (INIS)

    Yang, Sheng; Liu, Zhiqiang; Tang, Zhiyong; Wang, Yifan; Chen, Qianqian; Sun, Yuhan

    2017-01-01

    Highlights: • Solar energy integrated with natural-gas-to-methanol process is proposed. • The two processes are modeled and simulated. • Performance analysis of the two processes are conducted. • The proposed process can cut down the greenhouse gas emission. • The proposed process can save natural gas consumption. - Abstract: Methanol is an important platform chemical. Methanol production using natural gas as raw material has short processing route and well developed equipment and technology. However, natural gas reserves are not large in China. Solar energy power generation system integrated with natural-gas-to-methanol (NGTM) process is developed, which may provide a technical routine for methanol production in the future. The solar energy power generation produces electricity for reforming unit and system consumption in solar energy integrated natural-gas-to-methanol system (SGTM). Performance analysis of conventional natural-gas-to-methanol process and solar energy integrated with natural-gas-to-methanol process are presented based on simulation results. Performance analysis was conducted considering carbon efficiency, production cost, solar energy price, natural gas price, and carbon tax. Results indicate that solar energy integrated with natural-gas-to-methanol process is able to cut down the greenhouse gas (GHG) emission. In addition, solar energy can replace natural gas as fuel. This can reduce the consumption of natural gas, which equals to 9.2% of the total consumed natural gas. However, it is not economical considering the current technology readiness level, compared with conventional natural-gas-to-methanol process.

  16. Mentoring: An Evolving Relationship.

    Science.gov (United States)

    Block, Michelle; Florczak, Kristine L

    2017-04-01

    The column concerns itself with mentoring as an evolving relationship between mentor and mentee. The collegiate mentoring model, the transformational transcendence model, and the humanbecoming mentoring model are considered in light of a dialogue with mentors at a Midwest university and conclusions are drawn.

  17. Methods Evolved by Observation

    Science.gov (United States)

    Montessori, Maria

    2016-01-01

    Montessori's idea of the child's nature and the teacher's perceptiveness begins with amazing simplicity, and when she speaks of "methods evolved," she is unveiling a methodological system for observation. She begins with the early childhood explosion into writing, which is a familiar child phenomenon that Montessori has written about…

  18. Comparison of Boolean analysis and standard phylogenetic methods using artificially evolved and natural mt-tRNA sequences from great apes.

    Science.gov (United States)

    Ari, Eszter; Ittzés, Péter; Podani, János; Thi, Quynh Chi Le; Jakó, Eena

    2012-04-01

    Boolean analysis (or BOOL-AN; Jakó et al., 2009. BOOL-AN: A method for comparative sequence analysis and phylogenetic reconstruction. Mol. Phylogenet. Evol. 52, 887-97.), a recently developed method for sequence comparison uses the Iterative Canonical Form of Boolean functions. It considers sequence information in a way entirely different from standard phylogenetic methods (i.e. Maximum Parsimony, Maximum-Likelihood, Neighbor-Joining, and Bayesian analysis). The performance and reliability of Boolean analysis were tested and compared with the standard phylogenetic methods, using artificially evolved - simulated - nucleotide sequences and the 22 mitochondrial tRNA genes of the great apes. At the outset, we assumed that the phylogeny of Hominidae is generally well established, and the guide tree of artificial sequence evolution can also be used as a benchmark. These offer a possibility to compare and test the performance of different phylogenetic methods. Trees were reconstructed by each method from 2500 simulated sequences and 22 mitochondrial tRNA sequences. We also introduced a special re-sampling method for Boolean analysis on permuted sequence sites, the P-BOOL-AN procedure. Considering the reliability values (branch support values of consensus trees and Robinson-Foulds distances) we used for simulated sequence trees produced by different phylogenetic methods, BOOL-AN appeared as the most reliable method. Although the mitochondrial tRNA sequences of great apes are relatively short (59-75 bases long) and the ratio of their constant characters is about 75%, BOOL-AN, P-BOOL-AN and the Bayesian approach produced the same tree-topology as the established phylogeny, while the outcomes of Maximum Parsimony, Maximum-Likelihood and Neighbor-Joining methods were equivocal. We conclude that Boolean analysis is a promising alternative to existing methods of sequence comparison for phylogenetic reconstruction and congruence analysis. Copyright © 2012 Elsevier Inc. All

  19. Consistency Analysis and Data Consultation of Gas System of Gas-Electricity Network of Latvia

    Science.gov (United States)

    Zemite, L.; Kutjuns, A.; Bode, I.; Kunickis, M.; Zeltins, N.

    2018-02-01

    In the present research, the main critical points of gas transmission and storage system of Latvia have been determined to ensure secure and reliable gas supply among the Baltic States to fulfil the core objectives of the EU energy policies. Technical data of critical points of the gas transmission and storage system of Latvia have been collected and analysed with the SWOT method and solutions have been provided to increase the reliability of the regional natural gas system.

  20. US Department of Energy investments in natural gas R ampersand D: An analysis of the gas industry proposal

    International Nuclear Information System (INIS)

    Sutherland, R.J.

    1992-01-01

    The natural gas industry has proposed an increase in the DOE gas R ampersand D budget from about $100 million to about $250 million per year for each of the next 10 years. The proposal includes four programs: natural gas supplies, fuel cells, natural gas vehicles and stationary combustion systems. This paper is a qualitative assessment of the gas industry proposal and recommends a natural gas R ampersand D strategy for the DOE. The methodology is a conceptual framework based on an analysis of market failures and the energy policy objectives of the DOE's (1991) National Energy Strategy. This framework would assist the DOE in constructing an R ampersand D portfolio that achieves energy policy objectives. The natural gas supply program is recommended to the extent that it contributes to energy price stability. Stationary combustion programs are supported on grounds of economic efficiency and environmental quality. The fuel cell program is supported on grounds of environmental quality. The natural gas vehicle program may potentially contribute to environmental quality and energy price stability. The R ampersand D programs in natural gas vehicles and in fuel cells should be complemented with policies that encourage the commercialization and use of the technology, not merely its development

  1. Structural decomposition analysis of Australia's greenhouse gas emissions

    International Nuclear Information System (INIS)

    Wood, Richard

    2009-01-01

    A complex system of production links our greenhouse gas emissions to our consumer demands. Whilst progress may be made in improving efficiency, other changes in the production structure may easily annul global improvements. Utilising a structural decomposition analysis, a comparative-static technique of input-output analysis, over a time period of around 30 years, net greenhouse emissions are decomposed in this study into the effects, due to changes in industrial efficiency, forward linkages, inter-industry structure, backward linkages, type of final demand, cause of final demand, population affluence, population size, and mix and level of exports. Historically, significant competing forces at both the whole of economy and industrial scale have been mitigating potential improvements. Key sectors and structural influences are identified that have historically shown the greatest potential for change, and would likely have the greatest net impact. Results clearly reinforce that the current dichotomy of growth and exports are the key problems in need of address.

  2. Practical approach on gas pipeline compression system availability analysis

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Sidney Pereira dos [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Kurz, Rainer; Lubomirsky, Matvey [Solar Turbines, San Diego, CA (United States)

    2009-12-19

    Gas pipeline projects traditionally have been designed based on load factor and steady state flow. This approach exposes project sponsors to project sustainability risks due to potential losses of revenues and transportation contract penalties related to pipeline capacity shortage as consequence of compressor unit's unavailability. Such unavailability should previously be quantified during the design phase. This paper presents a case study and a methodology that highlights the practical benefits of applying Monte Carlo simulation for the compression system availability analysis in conjunction with quantitative risk analysis and economic feasibility study. Project economics main variables and their impacts on the project NPV (Net Present Value) are evaluated with their respective statistics distribution to quantify risk and support decision makers to adopt mitigating measures to guarantee competitiveness while protecting project sponsors from otherwise unpredictable risks. This practical approach is compared to load factor approach and the results are presented and evaluated. (author)

  3. Numerical analysis of the non-contacting gas face seals

    Science.gov (United States)

    Blasiak, S.

    2017-08-01

    The non-contacting gas face seals are used in high-performance devices where the main requirements are safety and reliability. Compliance with these requirements is made possible by careful research and analysis of physical processes related to, inter alia, fluid flow through the radial gap and ring oscillations susceptible to being housed in the enclosure under the influence of rotor kinematic forces. Elaborating and developing mathematical models describing these phenomena allows for more and more accurate analysis results. The paper presents results of studies on stationary ring oscillations made of different types of materials. The presented results of the research allow to determine which of the materials used causes the greatest amplitude of the vibration of the system fluid film-working rings.

  4. Analysis of Halogen-Mercury Reactions in Flue Gas

    Energy Technology Data Exchange (ETDEWEB)

    Paula Buitrago; Geoffrey Silcox; Constance Senior; Brydger Van Otten

    2010-01-01

    Oxidized mercury species may be formed in combustion systems through gas-phase reactions between elemental mercury and halogens, such as chorine or bromine. This study examines how bromine species affect mercury oxidation in the gas phase and examines the effects of mixtures of bromine and chlorine on extents of oxidation. Experiments were conducted in a bench-scale, laminar flow, methane-fired (300 W), quartz-lined reactor in which gas composition (HCl, HBr, NO{sub x}, SO{sub 2}) and temperature profile were varied. In the experiments, the post-combustion gases were quenched from flame temperatures to about 350 C, and then speciated mercury was measured using a wet conditioning system and continuous emissions monitor (CEM). Supporting kinetic calculations were performed and compared with measured levels of oxidation. A significant portion of this report is devoted to sample conditioning as part of the mercury analysis system. In combustion systems with significant amounts of Br{sub 2} in the flue gas, the impinger solutions used to speciate mercury may be biased and care must be taken in interpreting mercury oxidation results. The stannous chloride solution used in the CEM conditioning system to convert all mercury to total mercury did not provide complete conversion of oxidized mercury to elemental, when bromine was added to the combustion system, resulting in a low bias for the total mercury measurement. The use of a hydroxylamine hydrochloride and sodium hydroxide solution instead of stannous chloride showed a significant improvement in the measurement of total mercury. Bromine was shown to be much more effective in the post-flame, homogeneous oxidation of mercury than chlorine, on an equivalent molar basis. Addition of NO to the flame (up to 400 ppmv) had no impact on mercury oxidation by chlorine or bromine. Addition of SO{sub 2} had no effect on mercury oxidation by chlorine at SO{sub 2} concentrations below about 400 ppmv; some increase in mercury oxidation

  5. REVIEW ARTICLE: MODELLING AND ANALYSIS OF A GASOLINE ENGINE EXHAUST GAS SYSTEMS

    OpenAIRE

    Barhm Mohamad

    2018-01-01

    The engine exhaust gas behaviour is strongly influencing the engine performance. This paper presents the modelling and analysis of four stroke - gasoline engine exhaust gas systems. An automotive example is considered whereby the pulsating exhausts gas flow through an exhaust pipe and silencer are considered over a wide range of speeds. Analytical procedures are outlined enabling the general analysis and modelling of vehicle engine exhaust gas systems also in this paper present...

  6. Evolving Procurement Organizations

    DEFF Research Database (Denmark)

    Bals, Lydia; Laine, Jari; Mugurusi, Godfrey

    Procurement has to find further levers and advance its contribution to corporate goals continuously. This places pressure on its organization in order to facilitate its performance. Therefore, procurement organizations constantly have to evolve in order to match these demands. A conceptual model...... and external contingency factors and having a more detailed look at the structural dimensions chosen, beyond the well-known characteristics of centralization, formalization, participation, specialization, standardization and size. From a theoretical perspective, it opens up insights that can be leveraged...

  7. Symbiotic Composition and Evolvability

    OpenAIRE

    Watson, Richard A.; Pollack, Jordan B.

    2001-01-01

    Several of the Major Transitions in natural evolution, such as the symbiogenic origin of eukaryotes from prokaryotes, share the feature that existing entities became the components of composite entities at a higher level of organisation. This composition of pre-adapted extant entities into a new whole is a fundamentally different source of variation from the gradual accumulation of small random variations, and it has some interesting consequences for issues of evolvability. In this paper we p...

  8. Evolvable Neural Software System

    Science.gov (United States)

    Curtis, Steven A.

    2009-01-01

    The Evolvable Neural Software System (ENSS) is composed of sets of Neural Basis Functions (NBFs), which can be totally autonomously created and removed according to the changing needs and requirements of the software system. The resulting structure is both hierarchical and self-similar in that a given set of NBFs may have a ruler NBF, which in turn communicates with other sets of NBFs. These sets of NBFs may function as nodes to a ruler node, which are also NBF constructs. In this manner, the synthetic neural system can exhibit the complexity, three-dimensional connectivity, and adaptability of biological neural systems. An added advantage of ENSS over a natural neural system is its ability to modify its core genetic code in response to environmental changes as reflected in needs and requirements. The neural system is fully adaptive and evolvable and is trainable before release. It continues to rewire itself while on the job. The NBF is a unique, bilevel intelligence neural system composed of a higher-level heuristic neural system (HNS) and a lower-level, autonomic neural system (ANS). Taken together, the HNS and the ANS give each NBF the complete capabilities of a biological neural system to match sensory inputs to actions. Another feature of the NBF is the Evolvable Neural Interface (ENI), which links the HNS and ANS. The ENI solves the interface problem between these two systems by actively adapting and evolving from a primitive initial state (a Neural Thread) to a complicated, operational ENI and successfully adapting to a training sequence of sensory input. This simulates the adaptation of a biological neural system in a developmental phase. Within the greater multi-NBF and multi-node ENSS, self-similar ENI s provide the basis for inter-NBF and inter-node connectivity.

  9. Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

    Science.gov (United States)

    Shams, Bilal; Yao, Jun; Zhang, Kai; Zhang, Lei

    2017-08-01

    Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large amount of condensate in reservoir pores. Trapped condensate often is lost due to condensate accumulation-condensate blockage courtesy of high molecular weight, heavy condensate residue. Recovering lost condensate most economically and optimally has always been a challenging goal. Thus, gas cycling is applied to alleviate such a drastic loss in resources. In gas injection, the flooding pattern, injection timing and injection duration are key parameters to study an efficient EOR scenario in order to recover lost condensate. This work contains sensitivity analysis on different parameters to generate an accurate investigation about the effects on performance of different injection scenarios in homogeneous gas condensate system. In this paper, starting time of gas cycling and injection period are the parameters used to influence condensate recovery of a five-spot well pattern which has an injection pressure constraint of 3000 psi and production wells are constraint at 500 psi min. BHP. Starting injection times of 1 month, 4 months and 9 months after natural depletion areapplied in the first study. The second study is conducted by varying injection duration. Three durations are selected: 100 days, 400 days and 900 days. In miscible gas injection, miscibility and vaporization of condensate by injected gas is more efficient mechanism for condensate recovery. From this study, it is proven that the application of gas cycling on five-spot well pattern greatly enhances condensate recovery

  10. Analysis of a multicomponent gas absorption system with carrier gas coabsorption

    International Nuclear Information System (INIS)

    Merriman, J.R.

    1975-03-01

    Conventional integrated versions of the packed gas absorber design equations do not account for significant coabsorption of the carrier gas along with the dilute transferring species. These equations, as a result, also neglect the relationship between dilute component transfer and carrier gas coabsorption. In the absorption of Kr and Xe from various carrier gases, using CCl 2 F 2 as the process solvent, carrier coabsorption is substantial. Consequently, a design package was developed to deal with multicomponent gas absorption in systems characterized by carrier gas coabsorption. Developed within the general film theory framework, the basic feature of this design approach is a view of dilute component mass-transfer as a conventional diffusive transfer superimposed on a net flux caused by carrier absorption. Other supporting elements of the design package include predictive techniques for various fluid properties, estimating procedures for carrier gas equilibrium constants, and correlations for carrier gas and dilute gas mass-transfer coefficients. When applied to systems using CCl 2 F 2 as the solvent; He, N 2 , air, or Ar as the carrier gas; and Kr or Xe as the dilute gas; the design approach gave good results, even when extended to conditions well beyond those of its development. (U.S.)

  11. Risk analysis for a local gas distribution network

    International Nuclear Information System (INIS)

    Peters, J.W.

    1991-01-01

    Cost control and service reliability are popular topics when discussing strategic issues facing local distribution companies (LDCs) in the 1990s. The ability to provide secure and uninterrupted gas service is crucial for growth and company image, both with the public and regulatory agencies. At the same time, the industry is facing unprecedented competition from alternate fuels, and cost control is essential for maintaining a competitive edge in the market. On the surface, it would appear that cost control and service reliability are contradictory terms. Improvement in service reliability should cost something, or does it? Risk analysis can provide the answer from a distribution design perspective. From a gas distribution engineer's perspective, projects such as loops, backfeeds and even valve placement are designed to reduce, minimize and/or eliminate potential customer outages. These projects improve service reliability by acting as backups should a failure occur on a component of the distribution network. These contingency projects are cost-effective but their longterm benefit or true value is under question. Their purpose is to maintain supply to an area in the distribution network in the event of a failure somewhere else. Two phrases, potential customer outages and in the event of failure, identify uncertainty

  12. Environmental risk analysis for offshore oil and gas activities

    Energy Technology Data Exchange (ETDEWEB)

    Brude, Odd Willy; Aspholm, Ole O.; Rudberg, Anders [Det Norske Veritas (Brazil)

    2008-07-01

    Offshore oil and gas activities always have a risk for environmental impact due to potential accidental releases of oil and gas. The environmental risk can be calculated as a combination of the frequency of such accidents to occur and their environmental consequences in terms of environmental damage to habitats or populations. A method for conducting environmental risk analysis has been in use in Norwegian offshore waters for a decade, with a continuously refinement of methodology over the past years. This paper outlines the principles in the MIRA method and gives examples and discussions regarding use in different environmental compartments. The risk assessment starts with identification of oil spill scenarios with frequencies of potential release rates and spill durations. The next step is to model the oil drift for each accidental oil spill scenario. Drift and fate of oil is modeled probabilistic. Based on the oil spill scenarios and their probability of oil pollution, the potential environmental damage is quantified for each scenario. The endpoint of environmental damage is reduction of a population and the resulting recovery time (in years) for various species and habitats. Environmental risk levels are then evaluated against the operating companies' environmental acceptance criteria. (author)

  13. Segmentation of Residential Gas Consumers Using Clustering Analysis

    Directory of Open Access Journals (Sweden)

    Marta P. Fernandes

    2017-12-01

    Full Text Available The growing environmental concerns and liberalization of energy markets have resulted in an increased competition between utilities and a strong focus on efficiency. To develop new energy efficiency measures and optimize operations, utilities seek new market-related insights and customer engagement strategies. This paper proposes a clustering-based methodology to define the segmentation of residential gas consumers. The segments of gas consumers are obtained through a detailed clustering analysis using smart metering data. Insights are derived from the segmentation, where the segments result from the clustering process and are characterized based on the consumption profiles, as well as according to information regarding consumers’ socio-economic and household key features. The study is based on a sample of approximately one thousand households over one year. The representative load profiles of consumers are essentially characterized by two evident consumption peaks, one in the morning and the other in the evening, and an off-peak consumption. Significant insights can be derived from this methodology regarding typical consumption curves of the different segments of consumers in the population. This knowledge can assist energy utilities and policy makers in the development of consumer engagement strategies, demand forecasting tools and in the design of more sophisticated tariff systems.

  14. Thermal hydrodynamic analysis of a countercurrent gas centrifuge

    International Nuclear Information System (INIS)

    Andrade, Delvonei Alves de

    1999-01-01

    The influence of the thermal countercurrent on the separative performance of countercurrent centrifuges is treated in this work. The methodology used consists in modeling the gas flow inside the rotor under thermal boundary conditions supplied by the structural thermal model. The gas flow model, also called hydrodynamical model, is based on the Finite Volume Method for cylindrical geometry with azimuthal symmetry. The structural thermal model is based on the Nodal Method and take into account simultaneously, the conduction convection and radiation phenomena. The procedure adopted for this study consisted in the definition of the operational and geometric conditions of a centrifuge which was used as a pattern to the accomplished analysis. This configuration, called 'Standard Centrifuge', was used for the accomplishment of several simulations where the importance of the realistic boundary thermal conditions for the numerical evaluation of the centrifuge separative capacity was evidenced. A selective alteration for the optical properties based on simple engineering procedures was proposed. An improvement of 5% was obtained with this alteration. (author)

  15. Regional quality control survey of blood-gas analysis.

    Science.gov (United States)

    Minty, B D; Nunn, J F

    1977-09-01

    We undertook an external quality control survey of blood-gas analysis in 16 laboratories at 13 hospitals. All samples were prepared in the laboratories under investigation by equilibration of blood or serum with gas mixtures of known composition. pH of serum was measured with no significant bias but with an SD of random error 0.026 pH units, which was almost twice the SD of the reference range (0.015). An acceptable random error (half SD of reference range) was not obtained in a longitudinal internal quality control suvey although there were acceptable results for buffer pH in both field and internal surveys. Blood PO2 was measured with no significant bias but with SD of random error 1.38 kPa which reduced to 0.72 kPa by excluding one egregious result. The latter value was just over half of the SD of the reference range (1.2 kPa). PCO2 of blood was also measured without significant bias but with a much smaller SD of random error of 0.28 kPa (by excluding one egregious result), which was again just over half the SD of the reference range (0.51 kPa). Measurements of blood PO2 and PCO2 seem generally acceptable in relation to their respective reference ranges but measurements of pH were unsatisfactory in both internal and external trials.

  16. Gas storage services and regulation in Italy. A Delphi analysis

    International Nuclear Information System (INIS)

    Bonacina, Monica; Creti, Anna; Sileo, Antonio

    2009-01-01

    The objective of this paper is to assess to which extent gas market inefficiencies, such as weak competition, import dependence and lack of flexibility tools, affect operation and usage of storage services in Italy in the aftermath of the EU liberalization process. The analysis is supported by the empirical results of a Delphi survey that we have conducted to investigate storage service provision and regulation in Italy. We argue that the Italian storage sector is at a crossroads. The policy-driven phase of liberalization is ending and the market-driven phase has just begun. The former phase has granted fair access to storage, narrowed the likelihood of strategic behaviour by the incumbent and secured residential users against supply disruptions, but it has proved dynamically inefficient. Cost-reflective tariffs and low penalties for unbalances have both lowered incentives to expand the range of flexibility tools and penalized industrial customers demand. The market-driven phase has just started. The expected increase in working capacity and the entry of newcomers in the authorization process for new facilities are a progress towards the commercial use of storage. To this end, however, a further change in gas market design is needed: the creation of a well functioning spot market. (author)

  17. CFD analysis of gas explosions vented through relief pipes.

    Science.gov (United States)

    Ferrara, G; Di Benedetto, A; Salzano, E; Russo, G

    2006-09-21

    Vent devices for gas and dust explosions are often ducted to safe locations by means of relief pipes. However, the presence of the duct increases the severity of explosion if compared to simply vented vessels (i.e. compared to cases where no duct is present). Besides, the identification of the key phenomena controlling the violence of explosion has not yet been gained. Multidimensional models coupling, mass, momentum and energy conservation equations can be valuable tools for the analysis of such complex explosion phenomena. In this work, gas explosions vented through ducts have been modelled by a two-dimensional (2D) axi-symmetric computational fluid dynamic (CFD) model based on the unsteady Reynolds Averaged Navier Stokes (RANS) approach in which the laminar, flamelet and distributed combustion models have been implemented. Numerical test have been carried out by varying ignition position, duct diameter and length. Results have evidenced that the severity of ducted explosions is mainly driven by the vigorous secondary explosion occurring in the duct (burn-up) rather than by the duct flow resistance or acoustic enhancement. Moreover, it has been found out that the burn-up affects explosion severity due to the reduction of venting rate rather than to the burning rate enhancement through turbulization.

  18. Metaphysics methods development for high temperature gas cooled reactor analysis

    International Nuclear Information System (INIS)

    Seker, V.; Downar, T. J.

    2007-01-01

    Gas cooled reactors have been characterized as one of the most promising nuclear reactor concepts in the Generation-IV technology road map. Considerable research has been performed on the design and safety analysis of these reactors. However, the calculational tools being used to perform these analyses are not state-of-the-art and are not capable of performing detailed three-dimensional analyses. This paper presents the results of an effort to develop an improved thermal-hydraulic solver for the pebble bed type high temperature gas cooled reactors. The solution method is based on the porous medium approach and the momentum equation including the modified Ergun's resistance model for pebble bed is solved in three-dimensional geometry. The heat transfer in the pebble bed is modeled considering the local thermal non-equilibrium between the solid and gas, which results in two separate energy equations for each medium. The effective thermal conductivity of the pebble-bed can be calculated both from Zehner-Schluender and Robold correlations. Both the fluid flow and the heat transfer are modeled in three dimensional cylindrical coordinates and can be solved in steady-state and time dependent. The spatial discretization is performed using the finite volume method and the theta-method is used in the temporal discretization. A preliminary verification was performed by comparing the results with the experiments conducted at the SANA test facility. This facility is located at the Institute for Safety Research and Reactor Technology (ISR), Julich, Germany. Various experimental cases are modeled and good agreement in the gas and solid temperatures is observed. An on-going effort is to model the control rod ejection scenarios as described in the OECD/NEA/NSC PBMR-400 benchmark problem. In order to perform these analyses PARCS reactor simulator code will be coupled with the new thermal-hydraulic solver. Furthermore, some of the other anticipated accident scenarios in the benchmark

  19. Analysis of hydrodynamic regimes of operation of a gas pipeline from the Samotlor field to the Nizhnevartovsk gas refinery

    Energy Technology Data Exchange (ETDEWEB)

    Al' tshular, S A; Bragunov, N I; Ivanov, V N; Izmaylov, I Ye; Koroleva, L N

    1979-01-01

    Results are presented from studying the hydraulic losses of a gas-transport system. Oil gas in the first stage of separation of the Samotlor field according to the plan is transported on two gas pipelines to the Nizhnevartovsk and Belozersk gas refinery. On the route of the first gas pipeline in order to remove the released condensate, 12 gas-separator and condensate-settling tanks are installed. The second gas pipeline in the beginning, middle and end has asemblies for additional separation (separation (separator, drop-separator, condensate-collector). The studied material is presented in the form of the dependence of actual calculatedcoefficients of hydraulic resistance on the rate of gas supply in the range 80,000-230,000 m/sup 3//h (Re-(0.82.0) X 10/sup -6/. It has been established that with Re=1.6 X 10/sup -6/ the calculated and actual coeffic-ients of resistance become the same, while with smaller values of Re, the actual values exceed the calculated by 20-40%. In the opinion of the authors this difference is due to the effect of the liquid phase with low velocities of gas and the formation of stable foam. As a result of transillumination it was also established that the regime of flow on the ascending part is dispersion-ring and dispersion-semiring, and on the descending part stratified. Analysis of the transport of the gas-condensate stream with ring regime of flow permitted the authors to hypothesize transporting of gas without removal of the condensate. A certain increase in the coefficients of resistance for the case where the condensate is not removed from the gas pipeline is noted with experimental realization of the proposed variant. It is explained by the low velocities of gas in the beginning of the gas pipeline. It is stressed that the actual and calculated pressure differentials are distinguished less than the calculated and actual coefficients of resistance and that this indicates the practical preservation of the throughput of the gas pipeline.

  20. Analysis of hollow fibre membrane systems for multicomponent gas separation

    KAUST Repository

    Khalilpour, Rajab; Abbas, Ali; Lai, Zhiping; Pinnau, Ingo

    2013-01-01

    nonlinear differential algebraic equation system is solved via a combination of backward differentiation and Gauss-Seidel methods. Natural gas sweetening problem is investigated as a case study. Model parametric analyses of variables, namely feed gas quality

  1. Greenhouse gas emission inventory based on full energy chain analysis

    International Nuclear Information System (INIS)

    Dones, R.; Hirschberg, S.; Knoepfel, I.

    1996-01-01

    Methodology, characteristics, features and results obtained for greenhouse gases within the recent Swiss LCA study 'Environmental Life-Cycle Inventories of Energy Systems' are presented. The focus of the study is on existing average Full Energy Chains (FENCHs) in the electricity generation mixes in Europe and in Switzerland. The systems, including coal (hard coal and lignite), oil, natural gas, nuclear and hydro, are discussed one by one as well as part of the electricity mixes. Photovoltaic systems are covered separately since they are not included in the electricity mixes. A sensitivity analysis on methane leakage during long-range transport via pipeline is shown. Whilst within the current study emissions are not attributed to specific countries, the main sectors contributing to the total GHGs emissions calculated for the various FENCHs are specified. (author). 10 refs, 10 figs, 9 tabs

  2. Greenhouse gas emission inventory based on full energy chain analysis

    Energy Technology Data Exchange (ETDEWEB)

    Dones, R; Hirschberg, S [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Knoepfel, I [Federal Inst. of Technology Zurich, Zurich (Switzerland)

    1996-07-01

    Methodology, characteristics, features and results obtained for greenhouse gases within the recent Swiss LCA study `Environmental Life-Cycle Inventories of Energy Systems` are presented. The focus of the study is on existing average Full Energy Chains (FENCHs) in the electricity generation mixes in Europe and in Switzerland. The systems, including coal (hard coal and lignite), oil, natural gas, nuclear and hydro, are discussed one by one as well as part of the electricity mixes. Photovoltaic systems are covered separately since they are not included in the electricity mixes. A sensitivity analysis on methane leakage during long-range transport via pipeline is shown. Whilst within the current study emissions are not attributed to specific countries, the main sectors contributing to the total GHGs emissions calculated for the various FENCHs are specified. (author). 10 refs, 10 figs, 9 tabs.

  3. An analysis of the falling film gas-liquid reactor

    NARCIS (Netherlands)

    Davis, E.J.; Ouwerkerk-Dijkers, van M.P.; Venkatesh, S.

    1979-01-01

    A mathematical model of the falling film reactor is developed to predict the conversion and temperature distribution in the reactor as a function of the gas and liquid flow rates, physical properties, the feed composition of the reactive gas and carrier gas and other parameters of the system.

  4. Flammable gas tank safety program: Technical basis for gas analysis and monitoring

    International Nuclear Information System (INIS)

    Sherwood, D.J.

    1995-01-01

    Flammable gases generated in radioactive liquids. Twenty-five high level radioactive liquid waste storage tanks located underground at the Hanford Site are on a Flammable Gas Watch List because they contain waste which tends to retain the gases generated in it until rather large quantities are available for sudden release to the tank head space; if a tank is full it has little dome space, and a flammable concentration of gases could be produced--even if the tank is ventilated. If the waste has no tendency to retain gas generated in it then a continual flammable gas concentration in the tank dome space is established by the gas production rate and the tank ventilation rate (or breathing rate for unventilated tanks); this is also a potential problem for Flammable Gas Watch List tanks, and perhaps other Hanford tanks too. All Flammable Gas Watch List tanks will be fitted with Standard Hydorgen Monitoring Systems so that their behavior can be observed. In some cases, such as tank 241-SY-101, the data gathered from such observations will indicate that tank conditions need to be mitigated so that gas release events are either eliminated or rendered harmless. For example, a mixer pump was installed in tank 241-SY-101; operating the pump stirs the waste, replacing the large gas release events with small releases of gas that are kept below twenty-five percent of the lower flammability limit by the ventilation system. The concentration of hydrogen measured in Hanford waste tanks is greater than that of any other flammable gas. Hydrogen levels measured with a Standard Hydrogen Monitoring System in excess of 0.6 volume percent will cause Westinghouse Hanford Company to consider actions which will decrease the amount of flammable gas in the tank

  5. A versatile gas interface for routine radiocarbon analysis with a gas ion source

    Energy Technology Data Exchange (ETDEWEB)

    Wacker, L., E-mail: wacker@phys.ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Fahrni, S.M. [Department of Chemistry and Biochemistry, University of Bern, 3012 Berne (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, 3012 Berne (Switzerland); Paul Scherrer Institute (PSI), 5232 Villigen (Switzerland); Hajdas, I. [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Molnar, M. [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Institute of Nuclear Research, Hungarian Academy of Sciences, 4026 Debrecen (Hungary); Synal, H.-A. [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Szidat, S. [Department of Chemistry and Biochemistry, University of Bern, 3012 Berne (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, 3012 Berne (Switzerland); Zhang, Y.L. [Department of Chemistry and Biochemistry, University of Bern, 3012 Berne (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, 3012 Berne (Switzerland); Paul Scherrer Institute (PSI), 5232 Villigen (Switzerland)

    2013-01-15

    In 2010 more than 600 radiocarbon samples were measured with the gas ion source at the MIni CArbon DAting System (MICADAS) at ETH Zurich and the number of measurements is rising quickly. While most samples contain less than 50 {mu}g C at present, the gas ion source is attractive as well for larger samples because the time-consuming graphitization is omitted. Additionally, modern samples are now measured down to 5 per-mill counting statistics in less than 30 min with the recently improved gas ion source. In the versatile gas handling system, a stepping-motor-driven syringe presses a mixture of helium and sample CO{sub 2} into the gas ion source, allowing continuous and stable measurements of different kinds of samples. CO{sub 2} can be provided in four different ways to the versatile gas interface. As a primary method, CO{sub 2} is delivered in glass or quartz ampoules. In this case, the CO{sub 2} is released in an automated ampoule cracker with 8 positions for individual samples. Secondly, OX-1 and blank gas in helium can be provided to the syringe by directly connecting gas bottles to the gas interface at the stage of the cracker. Thirdly, solid samples can be combusted in an elemental analyzer or in a thermo-optical OC/EC aerosol analyzer where the produced CO{sub 2} is transferred to the syringe via a zeolite trap for gas concentration. As a fourth method, CO{sub 2} is released from carbonates with phosphoric acid in septum-sealed vials and loaded onto the same trap used for the elemental analyzer. All four methods allow complete automation of the measurement, even though minor user input is presently still required. Details on the setup, versatility and applications of the gas handling system are given.

  6. The Analysis of the Possible Thermal Emission at Radio Frequencies from an Evolved Supernova Remnant HB 3 (G132.7+1.3: Revisited

    Directory of Open Access Journals (Sweden)

    Onić, D.

    2008-12-01

    Full Text Available It has recently been reported that some of the flux density values for an evolved supernova remnant (SNR HB 3 (G132.7$+$1.3 are not accurate enough. In this work we therefore revised the analysis of the possible thermal emission at radio frequencies from this SNR using the recently published, corrected flux density values. A model including the sum of non-thermal (purely synchrotron and thermal (bremsstrahlung components is applied to fit the integrated radio spectrum of this SNR. The contribution of thermal component to the total volume emissivity at $1 mathrm{GHz}$ is estimated to be $approx37 \\%$. The ambient density is also estimated to be $napprox 9 mathrm{cm}^{-3}$ for $mathrm{T}=10^{4} mathrm{K}$. Again we obtained a relatively significant presence of thermal emission at radio frequencies from the SNR, which can support interaction between SNR HB 3 and adjacent molecular cloud associated with the mbox{H,{sc ii}} region W3. Our model estimates for thermal component contribution to total volume emissivity at $1 mathrm{GHz}$ and ambient density are similar to those obtained earlier ($approx40 \\%$, $approx10 mathrm{cm^{-3}}$. It is thus obvious that the corrected flux density values do not affect the basic conclusions.

  7. Data Association at the Level of Narrative Plots to Support Analysis of Spatiotemporal Evolvement of Conflict: A Case Study in Nigeria

    Directory of Open Access Journals (Sweden)

    Size Bi

    2016-10-01

    Full Text Available Open data sources regarding conflicts are increasingly enriched by broad social media; these yield a volume of information that exceeds our process capabilities. One of the critical factors is that knowledge extraction from mixed data formats requires systematic, sophisticated modeling. Here, we propose using text mining modeling tools for building associations of heterogeneous semi-structured data to enhance decision-making. Using narrative plots, text representation, and cluster analysis, we provide a data association framework that can mine spatiotemporal data that occur in similar contexts. The framework contains the following steps: (1 a novel text representation is presented to vectorize the textual semantics by learning both co-word features and word orders in a unified form; (2 text clustering technology is employed to associate events of interest with similar events in historical logs, based solely on narrative plots of the events; and (3 the inferred activity procedure is visualized via an evolving spatiotemporal map through the Kriging algorithm. Our results demonstrate that the approach enables deeper discrimination into the trends underlying conflicts and possesses a narrative reasoning forward prediction with a precision of 0.4817, in addition to a high consistency with the conclusions of existing studies.

  8. Optical Absorption Spectroscopy for Gas Analysis in Biomass Gasification

    DEFF Research Database (Denmark)

    Grosch, Helge

    important gas species of the low-temperature circulating fluidized bed gasifier. At first, a special gas cell,the hot gas flow cell (HGC), was build up and veried. In this custom-made gas cell, the optical properties, the so-called absorption cross-sections, of the most important sulfur and aromatic...... compounds were determined in laboratory experiments. By means of the laboratory results and spectroscopic databases,the concentrations of the major gas species and the aromatic compounds phenol and naphthalene were determined in extraction and in-situ measurements....

  9. Design and performance analysis of gas and liquid radial turbines

    Science.gov (United States)

    Tan, Xu

    In the first part of the research, pumps running in reverse as turbines are studied. This work uses experimental data of wide range of pumps representing the centrifugal pumps' configurations in terms of specific speed. Based on specific speed and specific diameter an accurate correlation is developed to predict the performances at best efficiency point of the centrifugal pump in its turbine mode operation. The proposed prediction method yields very good results to date compared to previous such attempts. The present method is compared to nine previous methods found in the literature. The comparison results show that the method proposed in this paper is the most accurate. The proposed method can be further complemented and supplemented by more future tests to increase its accuracy. The proposed method is meaningful because it is based both specific speed and specific diameter. The second part of the research is focused on the design and analysis of the radial gas turbine. The specification of the turbine is obtained from the solar biogas hybrid system. The system is theoretically analyzed and constructed based on the purchased compressor. Theoretical analysis results in a specification of 100lb/min, 900ºC inlet total temperature and 1.575atm inlet total pressure. 1-D and 3-D geometry of the rotor is generated based on Aungier's method. 1-D loss model analysis and 3-D CFD simulations are performed to examine the performances of the rotor. The total-to-total efficiency of the rotor is more than 90%. With the help of CFD analysis, modifications on the preliminary design obtained optimized aerodynamic performances. At last, the theoretical performance analysis on the hybrid system is performed with the designed turbine.

  10. An investigation of the matrix sensitivity of refinery gas analysis using gas chromatography with flame ionisation detection.

    Science.gov (United States)

    Ferracci, Valerio; Brown, Andrew S; Harris, Peter M; Brown, Richard J C

    2015-02-27

    The response of a flame ionisation detector (FID) on a gas chromatograph to methane, ethane, propane, i-butane and n-butane in a series of multi-component refinery gas standards was investigated to assess the matrix sensitivity of the instrument. High-accuracy synthetic gas standards, traceable to the International System of Units, were used to minimise uncertainties. The instrument response exhibited a small dependence on the component amount fraction: this behaviour, consistent with that of another FID, was thoroughly characterised over a wide range of component amount fractions and was shown to introduce a negligible bias in the analysis of refinery gas samples, provided a suitable reference standard is employed. No significant effects of the molar volume, density and viscosity of the gas mixtures on the instrument response were observed, indicating that the FID is suitable for the analysis of refinery gas mixtures over a wide range of component amount fractions provided that appropriate drift-correction procedures are employed. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Analysis of gob gas venthole production performances for strata gas control in longwall mining.

    Science.gov (United States)

    Karacan, C Özgen

    2015-10-01

    Longwall mining of coal seams affects a large area of overburden by deforming it and creating stress-relief fractures, as well as bedding plane separations, as the mining face progresses. Stress-relief fractures and bedding plane separations are recognized as major pathways for gas migration from gas-bearing strata into sealed and active areas of the mines. In order for strata gas not to enter and inundate the ventilation system of a mine, gob gas ventholes (GGVs) can be used as a methane control measure. The aim of this paper is to analyze production performances of GGVs drilled over a longwall panel. These boreholes were drilled to control methane emissions from the Pratt group of coals due to stress-relief fracturing and bedding plane separations into a longwall mine operating in the Mary Lee/Blue Creek coal seam of the Upper Pottsville Formation in the Black Warrior Basin, Alabama. During the course of the study, Pratt coal's reservoir properties were integrated with production data of the GGVs. These data were analyzed by using material balance techniques to estimate radius of influence of GGVs, gas-in-place and coal pressures, as well as their variations during mining. The results show that the GGVs drilled to extract gas from the stress-relief zone of the Pratt coal interval is highly effective in removing gas from the Upper Pottsville Formation. The radii of influence of the GGVs were in the order of 330-380 m, exceeding the widths of the panels, due to bedding plane separations and stress relieved by fracturing. Material balance analyses indicated that the initial pressure of the Pratt coals, which was around 648 KPa when longwall mining started, decreased to approximately 150 KPa as the result of strata fracturing and production of released gas. Approximately 70% of the initial gas-in-place within the area of influence of the GGVs was captured during a period of one year.

  12. Development of a Gas Systems Analysis Model (GSAM)

    International Nuclear Information System (INIS)

    Becker, A.B.; Pepper, W.J.

    1995-01-01

    Objective of developing this model (GSAM) is to create a comprehensive, nonproprietary, PC-based model of domestic gas industry activity. The system can assess impacts of various changes in the natural gas system in North America; individual and collective impacts due to changes in technology and economic conditions are explicitly modeled in GSAM. Major gas resources are all modeled, including conventional, tight, Devonian Shale, coalbed methane, and low-quality gas sources. The modeling system assesses all key components of the gas industry, including available resources, exploration, drilling, completion, production, and processing practices. Distribution, storage, and utilization of natural gas in a dynamic market-gased analytical structure is assessed. GSAM is designed to provide METC managers with a tool to project impacts of future research, development, and demonstration benefits

  13. Analysis of Specific Features of the Ukrainian Market of Natural Gas Production and Consumption

    Directory of Open Access Journals (Sweden)

    Lelyuk Oleksiy V.

    2013-11-01

    Full Text Available The article provides results of the study of specific features of the Ukrainian market of natural gas production and consumption. It analyses dynamics of the specific weight of Ukraine in general volumes of natural gas consumption in the world, dynamics of natural gas consumption in Ukraine during 1990 – 2012 and dependence of natural gas consumption on GDP volumes by the purchasing power parity. It studies the structure of natural gas consumption by regions in 2012 and sectors of economy, resource base of natural gas in Ukraine and also dynamics of established resources of natural gas in Ukraine and dynamics of natural gas production. It analyses base rates of growth of natural gas resources and production in Ukraine. It considers dynamics of import of natural gas into Ukraine and its import prices and also the structure of natural gas import. It identifies the balance of the natural gas market in Ukraine. On the basis of the conducted analysis the article proves that Ukraine is a gas-deficit country of the world, which depends on natural gas import supplies.

  14. Gas Analysis and Control Methods for Thermal Batteries

    Science.gov (United States)

    2013-09-01

    when using highly efficient microporous thermal insulation packages. An easily implemented method of H2 gas removal from vendor thermal batteries is... microporous thermal insulation packages (1, 4, 5) or reduce volume requirements significantly. More rigorous gas control methods combined with...measured from the DCM pressures and known internal volumes of the 3 GHS that were measured using the ideal gas law with a 10-cc internal volume SS

  15. Analysis of Sustainable Technologies for Acid Gas Removal

    OpenAIRE

    Dal Pozzo, Alessandro

    2017-01-01

    Acid gases, such as sulphur dioxide and hydrogen halides and – in a broad sense – carbon dioxide, are typical pollutants generated by combustion processes. Their removal by means of solid sorbents represent an efficient and cost-effective approach in dry acid gas treatment systems for waste incineration flue gas, while for CO2 capture the process is exploratively studied as a promising alternative to amine scrubbing. The present study addressed both aspects. In waste incineration flue gas ...

  16. Analysis of carbon dioxide emission of gas fuelled cogeneration plant

    International Nuclear Information System (INIS)

    Nordin, Adzuieen; Amin, M; Majid, A

    2013-01-01

    Gas turbines are widely used for power generation. In cogeneration system, the gas turbine generates electricity and the exhaust heat from the gas turbine is used to generate steam or chilled water. Besides enhancing the efficiency of the system, the process assists in reducing the emission of CO 2 to the environment. This study analyzes the amount of CO 2 emission by Universiti Teknologi Petronas gas fuelled cogeneration system using energy balance equations. The results indicate that the cogeneration system reduces the CO 2 emission to the environment by 60%. This finding could encourage the power plant owners to install heat recovery systems to their respective plants

  17. Analysis of carbon dioxide emission of gas fuelled cogeneration plant

    Science.gov (United States)

    Nordin, Adzuieen; Amin, M.; Majid, A.

    2013-12-01

    Gas turbines are widely used for power generation. In cogeneration system, the gas turbine generates electricity and the exhaust heat from the gas turbine is used to generate steam or chilled water. Besides enhancing the efficiency of the system, the process assists in reducing the emission of CO2 to the environment. This study analyzes the amount of CO2 emission by Universiti Teknologi Petronas gas fuelled cogeneration system using energy balance equations. The results indicate that the cogeneration system reduces the CO2 emission to the environment by 60%. This finding could encourage the power plant owners to install heat recovery systems to their respective plants.

  18. Analysis of a gas absorption system with soluble carrier gas and volatile solvent

    International Nuclear Information System (INIS)

    Kanak, B.E.

    1980-01-01

    The effects of column diameter, carrier gas coabsorption, and solvent vaporization on the performance of a packed gas absorption column are examined. The system investigated employs dichlorodifluoromethane as a solvent to remove krypton from a nitrogen stream and is characterized by substantial nitrogen coabsorption. Three columns with diameters of 2, 3, and 4 inches were constructed and packed with 34.5 inches of Goodloe packing. In addition to the more conventional data, the experimental evaluation of these columns included the use of a radioisotope and a gamma scanning technique which provided direct measurement of the columns' molar krypton profiles. A multicomponent gas absorption model was developed, based on the two-film mass transfer theory, that allows the fluxes of all species to interact. Verification of this model was achieved through comparison of the calculated results with experimental data. With the feed gas flow rate between 6 and 36 lb moles/hr-ft 2 and the solvent feed rate between 40 and 400 lb moles/hr-ft 2 , column diameter was found to have no significant impact on the mass transfer efficiency of this system when carried out in columns with diameters of 2 inches or greater. The absorption of krypton was found to be enhanced and inhibited, respectively, by carrier gas coabsorption and solvent vaporization. An injector system to add gaseous solvent to the feed gas stream prior to its introduction into the packed bed was proposed to eliminate the detrimental effects of solvent vaporization.Using this injector to supersaturate the feed gas stream with solvent enhanced absorber performance in the same manner as carrier gas coabsorption

  19. Evolving Procurement Organizations

    DEFF Research Database (Denmark)

    Bals, Lydia; Laiho, Aki; Laine, Jari

    Procurement has to find further levers and advance its contribution to corporate goals continuously. This places pressure on its organization in order to facilitate its performance. Therefore, Procurement organizations constantly have to evolve in order to match these demands. A conceptual model...... is presented and results of a first case study discussed. The findings highlight the importance of taking a contingency perspective on Procurement organization, understanding the internal and internal contingency factors. From a theoretical perspective, it opens up insights that can be furthermore leveraged...... in future studies in the fields of hybrid procurement organizations, global sourcing organizations as well as international procurement offices (IPOs). From a practical standpoint, an assessment of external and internal contingencies provides the opportunity to consciously match organization to its...

  20. Diffusion between evolving interfaces

    International Nuclear Information System (INIS)

    Juntunen, Janne; Merikoski, Juha

    2010-01-01

    Diffusion in an evolving environment is studied by continuous-time Monte Carlo simulations. Diffusion is modeled by continuous-time random walkers on a lattice, in a dynamic environment provided by bubbles between two one-dimensional interfaces driven symmetrically towards each other. For one-dimensional random walkers constrained by the interfaces, the bubble size distribution dominates diffusion. For two-dimensional random walkers, it is also controlled by the topography and dynamics of the interfaces. The results of the one-dimensional case are recovered in the limit where the interfaces are strongly driven. Even with simple hard-core repulsion between the interfaces and the particles, diffusion is found to depend strongly on the details of the dynamical rules of particles close to the interfaces.

  1. Analysis of an innovative process for landfill gas quality improvement

    International Nuclear Information System (INIS)

    Lombardi, L.; Carnevale, E.A.

    2016-01-01

    Low methane content landfill gas is not suitable for feeding engines and is generally flared. This type of landfill gas may be enriched by removing the inert carbon dioxide. An innovative process, based on the carbon dioxide captured by means of accelerated carbonation of bottom ash was proposed and studied for the above purpose. The process was investigated at a laboratory scale, simulating different landfill gas compositions. The enrichment process is able to decrease the carbon dioxide concentration from 70 to 80% in volume to 60% in volume, requiring about 36 kg of bottom ash per Nm"3 of landfill gas. Using this result it was estimated that an industrial scale plant, processing 100–1000 Nm"3/h of low methane content landfill gas requires about 28,760–2,87,600 t of bottom ash for a one year operation. The specific cost of the studied enrichment process was evaluated as well and ranges from 0.052 to 0.241 Euro per Nm"3 of entering landfill gas. The energy balance showed that about 4–6% of the energy entered with the landfill gas is required for carrying out the enrichment, while the use of the enriched landfill gas in the engine producing electricity allows for negative carbon dioxide emission. - Highlights: • The process uses a waste stream as material to capture CO_2. • The process uses a simple gas/solid fixed bed contact reactor at ambient conditions. • The process captures the CO_2 to enrich low-CH4 landfill gas. • The specific cost ranges from 0.052 to 0.241 Euro per Nm"3 of entering landfill gas. • The process consumes about 4–6% of the entering energy and acts as CO_2 sink.

  2. Economics of lifecycle analysis and greenhouse gas regulations

    Science.gov (United States)

    Rajagopal, Deepak

    2009-11-01

    Interest in alternatives to fossil fuels has risen significantly during the current decade. Although a variety of different alternative technologies have experienced rapid growth, biofuels have emerged as the main alternative transportation fuel. Energy policies in several countries envision blending biofuels with fossil fuels as the main mechanism to increase energy independence and energy security. Climate change policies in several regions are also riding on the same hope for reducing emissions from transportation. The main advantage of biofuels is that they are technically mature, cheaper to produce and more convenient to use relative to other alternative fuels. However, the impact of current biofuels on the environment and on economic welfare, is controversial. In my dissertation I focus on three topics relevant to future energy and climate policies. The first is the economics of lifecycle analysis and its application to the assessment of environmental impact of biofuel policies. The potential of biofuel for reducing greenhouse gas emissions was brought to the fore by research that relied on the methodology called lifecycle analysis (LCA). Subsequent research however showed that the traditional LCA fails to account for market-mediated effects that will arise when biofuel technologies are scaled up. These effects can increase or decrease emissions at each stage of the lifecycle. I discuss how the LCA will differ depending on the scale, a single firm versus a region and why LCA of the future should be distinguished from LCA of the past. I describe some approaches for extending the LCA methodology so that it can be applied under these different situations. The second topic is the economic impact of biofuels. Biofuels reduce the demand for oil and increase the demand for agricultural goods. To high income countries which tend to be both large importers of oil and large exporters of agricultural goods, this implies two major benefits. One of the one hand it reduces

  3. Analysis of a sustainable gas cooled fast breeder reactor concept

    International Nuclear Information System (INIS)

    Kumar, Akansha; Chirayath, Sunil S.; Tsvetkov, Pavel V.

    2014-01-01

    Highlights: • A Thorium-GFBR breeder for actinide recycling ability, and thorium fuel feasibility. • A mixture of 232 Th and 233 U is used as fuel and LWR used fuel is used. • Detailed neutronics, fuel cycle, and thermal-hydraulics analysis has been presented. • Run this TGFBR for 20 years with breeding of 239 Pu and 233 U. • Neutronics analysis using MCNP and Brayton cycle for energy conversion are used. - Abstract: Analysis of a thorium fuelled gas cooled fast breeder reactor (TGFBR) concept has been done to demonstrate the self-sustainability, breeding capability, actinide recycling ability, and thorium fuel feasibility. Simultaneous use of 232 Th and used fuel from light water reactor in the core has been considered. Results obtained confirm the core neutron spectrum dominates in an intermediate energy range (peak at 100 keV) similar to that seen in a fast breeder reactor. The conceptual design achieves a breeding ratio of 1.034 and an average fuel burnup of 74.5 (GWd)/(MTHM) . TGFBR concept is to address the eventual shortage of 235 U and nuclear waste management issues. A mixture of thorium and uranium ( 232 Th + 233 U) is used as fuel and light water reactor used fuel is utilized as blanket, for the breeding of 239 Pu. Initial feed of 233 U has to be obtained from thorium based reactors; even though there are no thorium breeders to breed 233 U a theoretical evaluation has been used to derive the data for the source of 233 U. Reactor calculations have been performed with Monte Carlo radiation transport code, MCNP/MCNPX. It is determined that this reactor has to be fuelled once every 5 years assuming the design thermal power output as 445 MW. Detailed analysis of control rod worth has been performed and different reactivity coefficients have been evaluated as part of the safety analysis. The TGFBR concept demonstrates the sustainability of thorium, viability of 233 U as an alternate to 235 U and an alternate use for light water reactor used fuel as a

  4. Simple gas chromatographic system for analysis of microbial respiratory gases

    Science.gov (United States)

    Carle, G. C.

    1972-01-01

    Dual column ambient temperature system, consisting of pair of capillary columns, microbead thermistor detector and micro gas-sampling valve, is used in remote life-detection equipment for space experiments. Performance outweighs advantage gained by utilizing single-column systems to reduce weight, conserve carrier gas and operate at lower power levels.

  5. Recent Advances in Water Analysis with Gas Chromatograph Mass Spectrometers

    Science.gov (United States)

    MacAskill, John A.; Tsikata, Edem

    2014-01-01

    We report on progress made in developing a water sampling system for detection and analysis of volatile organic compounds in water with a gas chromatograph mass spectrometer (GCMS). Two approaches are described herein. The first approach uses a custom water pre-concentrator for performing trap and purge of VOCs from water. The second approach uses a custom micro-volume, split-splitless injector that is compatible with air and water. These water sampling systems will enable a single GC-based instrument to analyze air and water samples for VOC content. As reduced mass, volume, and power is crucial for long-duration, manned space-exploration, these water sampling systems will demonstrate the ability of a GCMS to monitor both air and water quality of the astronaut environment, thereby reducing the amount of required instrumentation for long duration habitation. Laboratory prototypes of these water sampling systems have been constructed and tested with a quadrupole ion trap mass spectrometer as well as a thermal conductivity detector. Presented herein are details of these water sampling system with preliminary test results.

  6. Applications of laser-photoacoustic gas analysis method

    Energy Technology Data Exchange (ETDEWEB)

    Hernberg, R.; Stenberg, J. [Tampere Univ. of Technology (Finland). Dept. of Physics

    1996-12-01

    The dynamic behavior of a circulating fluidized bed boiler (CFB) was studied using two high speed gas analysis systems during combustion of coal, peat and wood chips. Time resolved concentrations of some pollutants (SO{sub 2}, NO, NH{sub 3} and H{sub 2}S) were measured using laser induced photoacoustic spectroscopy (LIPS). A zirkonia cell based probe (lambda-probe) was used in synchronization with the LIPS-probe to measure fluctuations between reducing and oxidizing conditions. The two probes were positioned in the same measurement volume on the center-line of the combustion chamber of the CFB. The purpose of the measurements was to investigate the behavior of the LIPS in a combustion chamber containing large amounts of other unburnt hydrocarbons. The correlations between oxidizing and reducing conditions and concentrations at three locations in the combustion chamber are presented. The best correlations were found in the upper part of the CFB combustion chamber. In some cases the correlations between reducing conditions and the LIPS signal were caused by hydrocarbons. Comparison of the average values obtained by the LIPS-system for NO and SO{sub 2} with the result from a sampling probe system connected to on-line analysers was also carried out. (author)

  7. Unsteady thermal analysis of gas-cooled fast reactor core

    International Nuclear Information System (INIS)

    Lakkis, I.A.

    1993-01-01

    This thesis presents numerical analysis of transient heat transfer in an equivalent coolant-fuel rod cell of a typical gas cooled, fast nuclear reactor core. The transient performance is assumed to follow a complete sudden loss of coolant starting from steady state operation. Steady state conditions are obtained from solving a conduction problem in the fuel rod and a parabolic turbutent convection problem in the coolant section. The coupling between the two problems is accomplished by ensuring continuity of the thermal conditions at the interface between the fuel rod and the coolant. to model turbulence, the mixing tenght theory is used. Various fuel rod configurations have been tested for optimal transient performance. Actually, the loss of coolant accident occurs gradually at an exponential rate. Moreover, a time delay before shutting down the reactor by insertion of control rods usually exists. It is required to minimize maximum steady state cladding temperature so that the time required to reach its limiting value during transient state is maximum. This will prevent the escape of radioactive gases that endanger the environment and the public. However, the case considered here is a limiting case representing what could actually happen in the worst probable accident. So, the resutls in this thesis are very indicative regarding selection of the fuel rode configuration for better transient performance in case of accidents in which complete loss of collant occurs instantaneously

  8. Screening of Gas-Cooled Reactor Thermal-Hydraulic and Safety Analysis Tools and Experimental Database

    International Nuclear Information System (INIS)

    Lee, Won Jae; Kim, Min Hwan; Lee, Seung Wook

    2007-08-01

    This report is a final report of I-NERI Project, 'Screening of Gas-cooled Reactor Thermal Hydraulic and Safety Analysis Tools and Experimental Database 'jointly carried out by KAERI, ANL and INL. In this study, we developed the basic technologies required to develop and validate the VHTR TH/safety analysis tools and evaluated the TH/safety database information. The research tasks consist of; 1) code qualification methodology (INL), 2) high-level PIRTs for major nucleus set of events (KAERI, ANL, INL), 3) initial scaling and scoping analysis (ANL, KAERI, INL), 4) filtering of TH/safety tools (KAERI, INL), 5) evaluation of TH/safety database information (KAERI, INL, ANL) and 6) key scoping analysis (KAERI). The code qualification methodology identifies the role of PIRTs in the R and D process and the bottom-up and top-down code validation methods. Since the design of VHTR is still evolving, we generated the high-level PIRTs referencing 600MWth block-type GT-MHR and 400MWth pebble-type PBMR. Nucleus set of events that represents the VHTR safety and operational transients consists of the enveloping scenarios of HPCC (high pressure conduction cooling: loss of primary flow), LPCC/Air-Ingress (low pressure conduction cooling: loss of coolant), LC (load changes: power maneuvering), ATWS (anticipated transients without scram: reactivity insertion), WS (water ingress: water-interfacing system break) and HU (hydrogen-side upset: loss of heat sink). The initial scaling analysis defines dimensionless parameters that need to be reflected in mixed convection modeling and the initial scoping analysis provided the reference system transients used in the PIRTs generation. For the PIRTs phenomena, we evaluated the modeling capability of the candidate TH/safety tools and derived a model improvement need. By surveying and evaluating the TH/safety database information, a tools V and V matrix has been developed. Through the key scoping analysis using available database, the modeling

  9. Screening of Gas-Cooled Reactor Thermal-Hydraulic and Safety Analysis Tools and Experimental Database

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Jae; Kim, Min Hwan; Lee, Seung Wook (and others)

    2007-08-15

    This report is a final report of I-NERI Project, 'Screening of Gas-cooled Reactor Thermal Hydraulic and Safety Analysis Tools and Experimental Database 'jointly carried out by KAERI, ANL and INL. In this study, we developed the basic technologies required to develop and validate the VHTR TH/safety analysis tools and evaluated the TH/safety database information. The research tasks consist of; 1) code qualification methodology (INL), 2) high-level PIRTs for major nucleus set of events (KAERI, ANL, INL), 3) initial scaling and scoping analysis (ANL, KAERI, INL), 4) filtering of TH/safety tools (KAERI, INL), 5) evaluation of TH/safety database information (KAERI, INL, ANL) and 6) key scoping analysis (KAERI). The code qualification methodology identifies the role of PIRTs in the R and D process and the bottom-up and top-down code validation methods. Since the design of VHTR is still evolving, we generated the high-level PIRTs referencing 600MWth block-type GT-MHR and 400MWth pebble-type PBMR. Nucleus set of events that represents the VHTR safety and operational transients consists of the enveloping scenarios of HPCC (high pressure conduction cooling: loss of primary flow), LPCC/Air-Ingress (low pressure conduction cooling: loss of coolant), LC (load changes: power maneuvering), ATWS (anticipated transients without scram: reactivity insertion), WS (water ingress: water-interfacing system break) and HU (hydrogen-side upset: loss of heat sink). The initial scaling analysis defines dimensionless parameters that need to be reflected in mixed convection modeling and the initial scoping analysis provided the reference system transients used in the PIRTs generation. For the PIRTs phenomena, we evaluated the modeling capability of the candidate TH/safety tools and derived a model improvement need. By surveying and evaluating the TH/safety database information, a tools V and V matrix has been developed. Through the key scoping analysis using available database, the

  10. Economic impact analysis of natural gas development and the policy implications

    International Nuclear Information System (INIS)

    De Silva, P.N.K.; Simons, S.J.R.; Stevens, P.

    2016-01-01

    In the US, the shale gas revolution ensured that the development costs of unconventional natural gas plummeted to the levels of $2–3/Mcf. This success has motivated the development of shale gas in other regions, including Australia and Europe. This study, focussing primarily on aspects of economic impact analysis, estimates the development costs of shale gas extraction in both Australia and Europe, based on both direct and fiscal costs, and also suggests policy initiatives. The increasing liquefied natural gas (LNG) developments in Australia are already straining domestic gas supplies. Hence, the development of more natural gas resources has been given a high priority. However, a majority of the Australian shale resources is non-marine in origin and significantly different to the marine-type shales in the US. In addition, the challenges of high development costs and the lack of infrastructure, service capacity and effective government policy are inhibiting shale gas development. Increasing the attractiveness of low risk investment by new, local, developers is critical for Australian shale gas success, which will simultaneously increase domestic gas security. In the European context, unconventional gas development will be challenged by direct, rather than fiscal costs. High direct costs will translate into average overall gas development costs over $13/Mcf, which is well over the existing market price. - Highlights: • The shale gas development potential of US, Europe and Australia are compared. • An economic impact analysis of shale gas development in Europe and Australia. • Factors important for shale gas development are discussed. • Policy pathways are suggested for shale gas development

  11. A multi vector energy analysis for interconnected power and gas systems

    International Nuclear Information System (INIS)

    Devlin, Joseph; Li, Kang; Higgins, Paraic; Foley, Aoife

    2017-01-01

    Highlights: • The first multi vector energy system analysis for Britain and Ireland is performed. • Extreme weather driven gas demands were utilised to increase gas system stress. • GB gas system is capable of satisfying demand but restricts gas generator ramping. • Irish gas system congestion causes a 40% increase in gas generator short run cost. • Gas storage in Ireland relieved congestion reduced operational costs by 14%. - Abstract: This paper presents the first multi vector energy analysis for the interconnected energy systems of Great Britain (GB) and Ireland. Both systems share a common high penetration of wind power, but significantly different security of supply outlooks. Ireland is heavily dependent on gas imports from GB, giving significance to the interconnected aspect of the methodology in addition to the gas and power interactions analysed. A fully realistic unit commitment and economic dispatch model coupled to an energy flow model of the gas supply network is developed. Extreme weather events driving increased domestic gas demand and low wind power output were utilised to increase gas supply network stress. Decreased wind profiles had a larger impact on system security than high domestic gas demand. However, the GB energy system was resilient during high demand periods but gas network stress limited the ramping capability of localised generating units. Additionally, gas system entry node congestion in the Irish system was shown to deliver a 40% increase in short run costs for generators. Gas storage was shown to reduce the impact of high demand driven congestion delivering a reduction in total generation costs of 14% in the period studied and reducing electricity imports from GB, significantly contributing to security of supply.

  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. Well-to-wheel analysis of direct and indirect use of natural gas in passenger vehicles

    International Nuclear Information System (INIS)

    Curran, Scott J.; Wagner, Robert M.; Graves, Ronald L.; Keller, Martin; Green, Johney B.

    2014-01-01

    The abundance of natural gas in the United States because of the number of existing natural gas reserves and the recent advances in extracting unconventional reserves has been one of the main drivers for low natural gas prices. A question arises of what is the optimal use of natural gas as a transportation fuel. Is it more efficient to use natural gas in a stationary power application to generate electricity to charge electric vehicles, compress natural gas for onboard combustion in vehicles, or re-form natural gas into a denser transportation fuel? This study investigates the well-to-wheels energy use and greenhouse gas emissions from various natural gas to transportation fuel pathways and compares the results to conventional gasoline vehicles and electric vehicles using the US electrical generation mix. Specifically, natural gas vehicles running on compressed natural gas are compared against electric vehicles charged with electricity produced solely from natural gas combustion in stationary power plants. The results of the study show that the dependency on the combustion efficiency of natural gas in stationary power can outweigh the inherent efficiency of electric vehicles, thus highlighting the importance of examining energy use on a well-to-wheels basis. - Highlights: • Well-to-wheels analysis shows differences in use of natural gas for transportation. • Well-to-wheels approach needed to evaluate total energy use and greenhouse gas emissions. • Well-to-wheels energy and GHG (greenhouse gas) emissions depend on efficiency of the prime mover. • Efficiency of power generation critical for low GHG emissions with electric vehicles. • Fuel economy critical for low GHG emissions with compressed natural gas vehicles

  14. Why did heterospory evolve?

    Science.gov (United States)

    Petersen, Kurt B; Burd, Martin

    2017-08-01

    The primitive land plant life cycle featured the production of spores of unimodal size, a condition called homospory. The evolution of bimodal size distributions with small male spores and large female spores, known as heterospory, was an innovation that occurred repeatedly in the history of land plants. The importance of desiccation-resistant spores for colonization of the land is well known, but the adaptive value of heterospory has never been well established. It was an addition to a sexual life cycle that already involved male and female gametes. Its role as a precursor to the evolution of seeds has received much attention, but this is an evolutionary consequence of heterospory that cannot explain the transition from homospory to heterospory (and the lack of evolutionary reversal from heterospory to homospory). Enforced outcrossing of gametophytes has often been mentioned in connection to heterospory, but we review the shortcomings of this argument as an explanation of the selective advantage of heterospory. Few alternative arguments concerning the selective forces favouring heterospory have been proposed, a paucity of attention that is surprising given the importance of this innovation in land plant evolution. In this review we highlight two ideas that may lead us to a better understanding of why heterospory evolved. First, models of optimal resource allocation - an approach that has been used for decades in evolutionary ecology to help understand parental investment and other life-history patterns - suggest that an evolutionary increase in spore size could reach a threshold at which small spores yielding small, sperm-producing gametophytes would return greater fitness per unit of resource investment than would large spores and bisexual gametophytes. With the advent of such microspores, megaspores would evolve under frequency-dependent selection. This argument can account for the appearance of heterospory in the Devonian, when increasingly tall and complex

  15. CT analysis of intratumoral gas formation after hepatic tumor embolization

    International Nuclear Information System (INIS)

    Kim, Hyun Sook; Ahn, In Oak; Kim, Hyung Jin; Lee, Goo; Chung, Sung Hoon

    1994-01-01

    To evaluate the prevalence and the patterns of sterile gas shown at computed tomography(CT) after transarterial embolization(TAE) for primary hepatic tumor. Among 102 patients who performed TAE for hepatoma, thirty-four in whom follow-up CT was underwent constituted the basis of our study. At CT, we evaluated the patterns and locations of intratumoral gas. We also reviewed the clinical data to exclude an infectious origin of intratumoral gas. Of 34 patients, intratumoral gas was detected in 11 patients(32%), in all of whom Gelfoam was used as an embolic material. The initial tumor size measured at pre-TAE CT was larger in patients with intratumoral gas than in patients without it(p < 0.005). No specific patterns or locations of intratumoral gas were noted on CT scans. No patients had clinical signs and symptoms that suggested infection. Intratumoral gas formation without clinical evidence of infection is not an infrequent finding after TAE for hepatoma, especially when Gelfoam is used and when the tumor is larger in size. This finding may be a part of postinfarction syndrome and should not be misinterpreted as an postprocedural abscess formation

  16. Gas migration through cement slurries analysis: A comparative laboratory study

    Directory of Open Access Journals (Sweden)

    Arian Velayati

    2015-12-01

    Full Text Available Cementing is an essential part of every drilling operation. Protection of the wellbore from formation fluid invasion is one of the primary tasks of a cement job. Failure in this task results in catastrophic events, such as blow outs. Hence, in order to save the well and avoid risky and operationally difficult remedial cementing, slurry must be optimized to be resistant against gas migration phenomenon. In this paper, performances of the conventional slurries facing gas invasion were reviewed and compared with modified slurry containing special gas migration additive by using fluid migration analyzer device. The results of this study reveal the importance of proper additive utilization in slurry formulations. The rate of gas flow through the slurry in neat cement is very high; by using different types of additives, we observe obvious changes in the performance of the cement system. The rate of gas flow in neat class H cement was reported as 36000 ml/hr while the optimized cement formulation with anti-gas migration and thixotropic agents showed a gas flow rate of 13.8 ml/hr.

  17. PROTOCOL FOR GAS SAMPLING AND ANALYSIS IN STRANDED MARINE MAMMALS

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Yara Bernaldo de Quirós, Óscar González-Díaz, Manuel Arbelo, Marisa Andrada & Antonio Fernández ### Abstract Gas sampling in stranded marine mammals can now be performed in situ using the appropriate vacuum tubes, insulin syringes and an aspirometer. Glass vacuum tubes are used for extraction of gas from cavities such as the intestine, pterigoyd air sacs, pneumothorax or subcapsular emphysema as well as for storage of the gas sample at room temperature and pressure. Insulin s...

  18. Evolving a photosynthetic organelle

    Directory of Open Access Journals (Sweden)

    Nakayama Takuro

    2012-04-01

    Full Text Available Abstract The evolution of plastids from cyanobacteria is believed to represent a singularity in the history of life. The enigmatic amoeba Paulinella and its 'recently' acquired photosynthetic inclusions provide a fascinating system through which to gain fresh insight into how endosymbionts become organelles. The plastids, or chloroplasts, of algae and plants evolved from cyanobacteria by endosymbiosis. This landmark event conferred on eukaryotes the benefits of photosynthesis - the conversion of solar energy into chemical energy - and in so doing had a huge impact on the course of evolution and the climate of Earth 1. From the present state of plastids, however, it is difficult to trace the evolutionary steps involved in this momentous development, because all modern-day plastids have fully integrated into their hosts. Paulinella chromatophora is a unicellular eukaryote that bears photosynthetic entities called chromatophores that are derived from cyanobacteria and has thus received much attention as a possible example of an organism in the early stages of organellogenesis. Recent studies have unlocked the genomic secrets of its chromatophore 23 and provided concrete evidence that the Paulinella chromatophore is a bona fide photosynthetic organelle 4. The question is how Paulinella can help us to understand the process by which an endosymbiont is converted into an organelle.

  19. Fat: an evolving issue

    Directory of Open Access Journals (Sweden)

    John R. Speakman

    2012-09-01

    Work on obesity is evolving, and obesity is a consequence of our evolutionary history. In the space of 50 years, we have become an obese species. The reasons why can be addressed at a number of different levels. These include separating between whether the primary cause lies on the food intake or energy expenditure side of the energy balance equation, and determining how genetic and environmental effects contribute to weight variation between individuals. Opinion on whether increased food intake or decreased energy expenditure drives the obesity epidemic is still divided, but recent evidence favours the idea that food intake, rather than altered expenditure, is most important. There is more of a consensus that genetics explains most (probably around 65% of weight variation between individuals. Recent advances in genome-wide association studies have identified many polymorphisms that are linked to obesity, yet much of the genetic variance remains unexplained. Finding the causes of this unexplained variation will be an impetus of genetic and epigenetic research on obesity over the next decade. Many environmental factors – including gut microbiota, stress and endocrine disruptors – have been linked to the risk of developing obesity. A better understanding of gene-by-environment interactions will also be key to understanding obesity in the years to come.

  20. Evolving a photosynthetic organelle.

    Science.gov (United States)

    Nakayama, Takuro; Archibald, John M

    2012-04-24

    The evolution of plastids from cyanobacteria is believed to represent a singularity in the history of life. The enigmatic amoeba Paulinella and its 'recently' acquired photosynthetic inclusions provide a fascinating system through which to gain fresh insight into how endosymbionts become organelles.The plastids, or chloroplasts, of algae and plants evolved from cyanobacteria by endosymbiosis. This landmark event conferred on eukaryotes the benefits of photosynthesis--the conversion of solar energy into chemical energy--and in so doing had a huge impact on the course of evolution and the climate of Earth 1. From the present state of plastids, however, it is difficult to trace the evolutionary steps involved in this momentous development, because all modern-day plastids have fully integrated into their hosts. Paulinella chromatophora is a unicellular eukaryote that bears photosynthetic entities called chromatophores that are derived from cyanobacteria and has thus received much attention as a possible example of an organism in the early stages of organellogenesis. Recent studies have unlocked the genomic secrets of its chromatophore 23 and provided concrete evidence that the Paulinella chromatophore is a bona fide photosynthetic organelle 4. The question is how Paulinella can help us to understand the process by which an endosymbiont is converted into an organelle.

  1. Communicability across evolving networks.

    Science.gov (United States)

    Grindrod, Peter; Parsons, Mark C; Higham, Desmond J; Estrada, Ernesto

    2011-04-01

    Many natural and technological applications generate time-ordered sequences of networks, defined over a fixed set of nodes; for example, time-stamped information about "who phoned who" or "who came into contact with who" arise naturally in studies of communication and the spread of disease. Concepts and algorithms for static networks do not immediately carry through to this dynamic setting. For example, suppose A and B interact in the morning, and then B and C interact in the afternoon. Information, or disease, may then pass from A to C, but not vice versa. This subtlety is lost if we simply summarize using the daily aggregate network given by the chain A-B-C. However, using a natural definition of a walk on an evolving network, we show that classic centrality measures from the static setting can be extended in a computationally convenient manner. In particular, communicability indices can be computed to summarize the ability of each node to broadcast and receive information. The computations involve basic operations in linear algebra, and the asymmetry caused by time's arrow is captured naturally through the noncommutativity of matrix-matrix multiplication. Illustrative examples are given for both synthetic and real-world communication data sets. We also discuss the use of the new centrality measures for real-time monitoring and prediction.

  2. Evolving Concepts of Asthma

    Science.gov (United States)

    Ray, Anuradha; Wenzel, Sally E.

    2015-01-01

    Our understanding of asthma has evolved over time from a singular disease to a complex of various phenotypes, with varied natural histories, physiologies, and responses to treatment. Early therapies treated most patients with asthma similarly, with bronchodilators and corticosteroids, but these therapies had varying degrees of success. Similarly, despite initial studies that identified an underlying type 2 inflammation in the airways of patients with asthma, biologic therapies targeted toward these type 2 pathways were unsuccessful in all patients. These observations led to increased interest in phenotyping asthma. Clinical approaches, both biased and later unbiased/statistical approaches to large asthma patient cohorts, identified a variety of patient characteristics, but they also consistently identified the importance of age of onset of disease and the presence of eosinophils in determining clinically relevant phenotypes. These paralleled molecular approaches to phenotyping that developed an understanding that not all patients share a type 2 inflammatory pattern. Using biomarkers to select patients with type 2 inflammation, repeated trials of biologics directed toward type 2 cytokine pathways saw newfound success, confirming the importance of phenotyping in asthma. Further research is needed to clarify additional clinical and molecular phenotypes, validate predictive biomarkers, and identify new areas for possible interventions. PMID:26161792

  3. UKAEA'S evolving contract philosophy

    International Nuclear Information System (INIS)

    Nicol, R. D.

    2003-01-01

    The United Kingdom Atomic Energy Authority (UKAEA) has gone through fundamental change over the last ten years. At the heart of this change has been UKAEA's relationship with the contracting and supply market. This paper describes the way in which UKAEA actively developed the market to support the decommissioning programme, and how the approach to contracting has evolved as external pressures and demands have changed. UKAEA's pro-active approach to industry has greatly assisted the development of a healthy, competitive market for services supporting decommissioning in the UK. There have been difficult changes and many challenges along the way, and some retrenchment was necessary to meet regulatory requirements. Nevertheless, UKAEA has sustained a high level of competition - now measured in terms of competed spend as a proportion of competable spend - with annual out-turns consistently over 80%. The prime responsibility for market development will pass to the new Nuclear Decommissioning Authority (NDA) in 2005, as the owner, on behalf of the Government, of the UK's civil nuclear liabilities. The preparatory work for the NDA indicates that the principles established by UKAEA will be carried forward. (author)

  4. Characteristic Value Method of Well Test Analysis for Horizontal Gas Well

    Directory of Open Access Journals (Sweden)

    Xiao-Ping Li

    2014-01-01

    Full Text Available This paper presents a study of characteristic value method of well test analysis for horizontal gas well. Owing to the complicated seepage flow mechanism in horizontal gas well and the difficulty in the analysis of transient pressure test data, this paper establishes the mathematical models of well test analysis for horizontal gas well with different inner and outer boundary conditions. On the basis of obtaining the solutions of the mathematical models, several type curves are plotted with Stehfest inversion algorithm. For gas reservoir with closed outer boundary in vertical direction and infinite outer boundary in horizontal direction, while considering the effect of wellbore storage and skin effect, the pseudopressure behavior of the horizontal gas well can manifest four characteristic periods: pure wellbore storage period, early vertical radial flow period, early linear flow period, and late horizontal pseudoradial flow period. For gas reservoir with closed outer boundary both in vertical and horizontal directions, the pseudopressure behavior of the horizontal gas well adds the pseudosteady state flow period which appears after the boundary response. For gas reservoir with closed outer boundary in vertical direction and constant pressure outer boundary in horizontal direction, the pseudopressure behavior of the horizontal gas well adds the steady state flow period which appears after the boundary response. According to the characteristic lines which are manifested by pseudopressure derivative curve of each flow period, formulas are developed to obtain horizontal permeability, vertical permeability, skin factor, reservoir pressure, and pore volume of the gas reservoir, and thus the characteristic value method of well test analysis for horizontal gas well is established. Finally, the example study verifies that the new method is reliable. Characteristic value method of well test analysis for horizontal gas well makes the well test analysis

  5. Environmental analysis of natural gas life cycle; Analisi ambientale del ciclo di vita del gas naturale

    Energy Technology Data Exchange (ETDEWEB)

    Riva, A.; D' Angelosante, S.; Trebeschi, C. [Snam SpA, Rome (Italy)

    2000-12-01

    Life Cycle Assessment is a method aimed at identifying the environmental effects connected with a given product, process or activity during its whole life cycle. The evaluation of published studies and the application of the method to electricity production with fossil fuels, by using data from published databases and data collected by the gas industry, demonstrate the importance and difficulties to have reliable and updated data required for a significant life cycle assessment. The results show that the environmental advantages of natural gas over the other fossil fuels in the final use stage increase still further if the whole life cycle of the fuels, from production to final consumption, is taken into account. [Italian] L'analisi del ciclo di vita e' una metodologia che consente di identificare gli effetti ambientali associati ad un prodotto, processo o attivita' lungo il loro ciclo di vita. La valutazione di studi pubblicati e l'applicazione della metodologia alla produzione di energia elettrica da combustibili fossili, utilizzando dati provenienti da banche dati di letteratura e raccolti dall'industria del gas, dimostrano l'importanza e la difficolta' di avere a disposizione dati affidabili ed aggiornati, necessari per un'analisi significativa del ciclo di vita. I risultati mostrano che i vantaggi ambientali del gas naturale rispetto agli altri combustibili fossili nella fase di utilizzo finale, aumentano ulteriormente se si considera l'intero ciclo di vita dei diversi combustibili, dalla produzione al consumo finale.

  6. Direct analysis of ultra-trace semiconductor gas by inductively coupled plasma mass spectrometry coupled with gas to particle conversion-gas exchange technique.

    Science.gov (United States)

    Ohata, Masaki; Sakurai, Hiromu; Nishiguchi, Kohei; Utani, Keisuke; Günther, Detlef

    2015-09-03

    An inductively coupled plasma mass spectrometry (ICPMS) coupled with gas to particle conversion-gas exchange technique was applied to the direct analysis of ultra-trace semiconductor gas in ambient air. The ultra-trace semiconductor gases such as arsine (AsH3) and phosphine (PH3) were converted to particles by reaction with ozone (O3) and ammonia (NH3) gases within a gas to particle conversion device (GPD). The converted particles were directly introduced and measured by ICPMS through a gas exchange device (GED), which could penetrate the particles as well as exchange to Ar from either non-reacted gases such as an air or remaining gases of O3 and NH3. The particle size distribution of converted particles was measured by scanning mobility particle sizer (SMPS) and the results supported the elucidation of particle agglomeration between the particle converted from semiconductor gas and the particle of ammonium nitrate (NH4NO3) which was produced as major particle in GPD. Stable time-resolved signals from AsH3 and PH3 in air were obtained by GPD-GED-ICPMS with continuous gas introduction; however, the slightly larger fluctuation, which could be due to the ionization fluctuation of particles in ICP, was observed compared to that of metal carbonyl gas in Ar introduced directly into ICPMS. The linear regression lines were obtained and the limits of detection (LODs) of 1.5 pL L(-1) and 2.4 nL L(-1) for AsH3 and PH3, respectively, were estimated. Since these LODs revealed sufficiently lower values than the measurement concentrations required from semiconductor industry such as 0.5 nL L(-1) and 30 nL L(-1) for AsH3 and PH3, respectively, the GPD-GED-ICPMS could be useful for direct and high sensitive analysis of ultra-trace semiconductor gas in air. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Analysis of Gas Vent System in Overseas LILW Disposal Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ju Yub; Kim, Ju Youl [FNC Technology Co., Yongin (Korea, Republic of); Jung, Hae Ryong; Ha, Jae Chul [Korea Radioactive Waste Management Corporation, Daejeon (Korea, Republic of)

    2012-05-15

    A Low- and Intermediate-Level Radioactive Waste (LILW) disposal facility is currently under construction in Korea. It is located in the aquifer, 80{approx}130 m below the ground surface. Thus, it is expected that disposal facility will be saturated after closure and various gases will be generated from metal corrosion, microbial degradation of organic materials and radiolysis. Generated gases will move up to the upper part of the silo, and it will increase the pressure of the silo. Since the integrity of the engineered barrier could be damaged, development of effective gas vent system which can prevent the gas accumulation in the silo is essential. In order to obtain basic data needed to develop site-specific gas vent system, gas vent systems of Sweden, Finland and Switzerland, which have the disposal concept of underground facility, were analyzed

  8. Ion beam analysis of gas turbine blades: evaluation of refurbishment ...

    Indian Academy of Sciences (India)

    Abstract. Refurbishment of hot components of gas turbines damaged in the harsh working environments is neces- ... 3000 r.p.m. and fluid forces that can cause fracture, yield- ... 800, 1200 and 2000 grit by employing mechanical grinding.

  9. Analysis of regenerative thermal storage geometries for solar gas turbines

    CSIR Research Space (South Africa)

    Klein, P

    2014-08-01

    Full Text Available Ceramic heat regenerators are suited to providing thermal storage for concentrating solar power stations based on a recuperated gas turbine cycle. Randomly packed beds of spheres and saddles; honeycombs and checker bricks were identified...

  10. Ion beam analysis of gas turbine blades: evaluation of refurbishment ...

    Indian Academy of Sciences (India)

    Scanning proton microscopy was employed to evaluate the quality of refurbishment process of gas turbine ... environment of hot combustion gases occur due to various processes, such as .... performance of refurbished blades.7. Due to the ...

  11. Gas Chromatography-Mass Spectrometric Analysis and Insecticidal ...

    African Journals Online (AJOL)

    Tropical Journal of Pharmaceutical Research ... apelta aerial parts was analyzed by gas chromatography/mass spectrometric (GC/MS) to determine its composition. ... into a natural fumigant/insecticide for the control of stored product insects.

  12. Thermal Analysis of the Divertor Primary Heat Transfer System Piping During the Gas Baking Process

    International Nuclear Information System (INIS)

    Yoder, Graydon L. Jr.; Harvey, Karen; Ferrada, Juan J.

    2011-01-01

    A preliminary analysis has been performed examining the temperature distribution in the Divertor Primary Heat Transfer System (PHTS) piping and the divertor itself during the gas baking process. During gas baking, it is required that the divertor reach a temperature of 350 C. Thermal losses in the piping and from the divertor itself require that the gas supply temperature be maintained above that temperature in order to ensure that all of the divertor components reach the required temperature. The analysis described in this report was conducted in order to estimate the required supply temperature from the gas heater.

  13. GAS MIXING ANALYSIS IN A LARGE-SCALED SALTSTONE FACILITY

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S

    2008-05-28

    Computational fluid dynamics (CFD) methods have been used to estimate the flow patterns mainly driven by temperature gradients inside vapor space in a large-scaled Saltstone vault facility at Savannah River site (SRS). The purpose of this work is to examine the gas motions inside the vapor space under the current vault configurations by taking a three-dimensional transient momentum-energy coupled approach for the vapor space domain of the vault. The modeling calculations were based on prototypic vault geometry and expected normal operating conditions as defined by Waste Solidification Engineering. The modeling analysis was focused on the air flow patterns near the ventilated corner zones of the vapor space inside the Saltstone vault. The turbulence behavior and natural convection mechanism used in the present model were benchmarked against the literature information and theoretical results. The verified model was applied to the Saltstone vault geometry for the transient assessment of the air flow patterns inside the vapor space of the vault region using the potential operating conditions. The baseline model considered two cases for the estimations of the flow patterns within the vapor space. One is the reference nominal case. The other is for the negative temperature gradient between the roof inner and top grout surface temperatures intended for the potential bounding condition. The flow patterns of the vapor space calculated by the CFD model demonstrate that the ambient air comes into the vapor space of the vault through the lower-end ventilation hole, and it gets heated up by the Benard-cell type circulation before leaving the vault via the higher-end ventilation hole. The calculated results are consistent with the literature information. Detailed results and the cases considered in the calculations will be discussed here.

  14. Vibration analysis of gas turbine blade using FEM

    International Nuclear Information System (INIS)

    Iqbal, M.J.; Chohan, G.Y.; Khusnood, S.; Khan, M.A.

    2003-01-01

    In a typical turbo-machine, there is a stator row of blades, which guide the gases onto a rotor row of blades, to extract the mechanical power from the machine. A typical rotor blade was sees upstream disturbance from the stator row and as it rotates, receive a corresponding number of increasing and decreasing lift and moment forces alternating periodically, depending on the number of stator blades/nozzles/guide vanes. Thus all the blades in a turbo-machine receiver their major periodic excitation at a frequency equal to nozzle passing frequency. Since these forces are periodic, one has to consider several number of these harmonics in determining whether resonance takes place, when one of these harmonics coincides with any of the natural frequencies of the blades. Turbine blades have a variety of natural modes of vibration, predominantly as blade alone but also in combination with flexing of the disc rim. These mode occur at characteristic frequencies, which are determined by the distribution of mass and stiffness (in bending or torsion), resulting from the variable thickness over the blade area. Since the advent of steam turbines and their application in various sectors of industry, it is a common experience that a blade failure is a major cause of breakdown in these machines. Blade failures due to fatigue are predominantly vibration related. The dynamic loads on the blading can arise from many sources, the predominant being the source of the operation principles on which the machine is designed. This work deals with vibration analysis of a gas turbine blade using a finite element package ANSYS. Determined the natural frequencies and mode shapes for a turbine blade and a rectangular blade. Results have been validated experimentally using a rectangular blade. ANSYS results have also been compared against published results. (author)

  15. Cellular Analysis of Boltzmann Most Probable Ideal Gas Statistics

    Science.gov (United States)

    Cahill, Michael E.

    2018-04-01

    Exact treatment of Boltzmann's Most Probable Statistics for an Ideal Gas of Identical Mass Particles having Translational Kinetic Energy gives a Distribution Law for Velocity Phase Space Cell j which relates the Particle Energy and the Particle Population according toB e(j) = A - Ψ(n(j) + 1)where A & B are the Lagrange Multipliers and Ψ is the Digamma Function defined byΨ(x + 1) = d/dx ln(x!)A useful sufficiently accurate approximation for Ψ is given byΨ(x +1) ≈ ln(e-γ + x)where γ is the Euler constant (≈.5772156649) & so the above distribution equation is approximatelyB e(j) = A - ln(e-γ + n(j))which can be inverted to solve for n(j) givingn(j) = (eB (eH - e(j)) - 1) e-γwhere B eH = A + γ& where B eH is a unitless particle energy which replaces the parameter A. The 2 approximate distribution equations imply that eH is the highest particle energy and the highest particle population isnH = (eB eH - 1) e-γwhich is due to the facts that population becomes negative if e(j) > eH and kinetic energy becomes negative if n(j) > nH.An explicit construction of Cells in Velocity Space which are equal in volume and homogeneous for almost all cells is shown to be useful in the analysis.Plots for sample distribution properties using e(j) as the independent variable are presented.

  16. Analysis of temperature and pressure changes in liquefied natural gas (LNG) cryogenic tanks

    Science.gov (United States)

    Chen, Q.-S.; Wegrzyn, J.; Prasad, V.

    2004-10-01

    Liquefied natural gas (LNG) is being developed as a transportation fuel for heavy vehicles such as trucks and transit buses, to lessen the dependency on oil and to reduce greenhouse gas emissions. The LNG stations are properly designed to prevent the venting of natural gas (NG) from LNG tanks, which can cause evaporative greenhouse gas emissions and result in fluctuations of fuel flow and changes of fuel composition. Boil-off is caused by the heat added into the LNG fuel during the storage and fueling. Heat can leak into the LNG fuel through the shell of tank during the storage and through hoses and dispensers during the fueling. Gas from tanks onboard vehicles, when returned to LNG tanks, can add additional heat into the LNG fuel. A thermodynamic and heat transfer model has been developed to analyze different mechanisms of heat leak into the LNG fuel. The evolving of properties and compositions of LNG fuel inside LNG tanks is simulated. The effect of a number of buses fueled each day on the possible total fuel loss rate has been analyzed. It is found that by increasing the number of buses, fueled each day, the total fuel loss rate can be reduced significantly. It is proposed that an electric generator be used to consume the boil-off gas or a liquefier be used to re-liquefy the boil-off gas to reduce the tank pressure and eliminate fuel losses. These approaches can prevent boil-off of natural gas emissions, and reduce the costs of LNG as transportation fuel.

  17. New Jersey's natural gas shortage: a policy analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cecil, J.L.; Morell, D.

    1976-12-01

    The public policy problems associated with New Jersey's natural gas shortage are extremely complex and rather difficult to examine. They involve a blend of technology, politics and economics; of regulatory mandates and profit-motivated initiatives; of Federal and state interaction and conflict. To understand the state's gas shortage and to lay the basis for recommending measures to deal with it, information about the basic technology, the organization of the gas industry, the national regulatory posture, and the possible causes of the gas shortage encompasses Part I of the overall study. In Part II, the analysis turns from the national level to a direct examination of New Jersey's gas situation. In Part III, Chapter VIII, the following are considered: the state's supply of natural gas, distribution of these supply volumes within New Jersey by the four major gas utilities, and gas consumption patterns within the state as a whole and then for each major consuming sector (electric utility, industrial, commercial, and residential). This chapter concludes with an analysis of the impacts of the gas shortage to date in New Jersey, and of its probable effects in the near-term. In the final chapter, some tentative conclusions and broad suggestions are advanced for public policies to mitigate the gravity of the state's position with respect to natural gas. Analysis proceeds, in turn, through consideration of possible state actions in several areas: increasing total interstate gas supplies; increasing New Jersey's share of whatever national total exists; making greater (or more effective) use of alternate fuels; and moderating demand for gas through aggressive conservation policies. Some short-term measures to cope better with whatever level of gas shortage exists in the state at any particular time are suggested. 151 references. (MCW)

  18. Flammable gas tank safety program: Technical basis for gas analysis and monitoring

    International Nuclear Information System (INIS)

    Estey, S.D.

    1998-01-01

    Several Hanford waste tanks have been observed to exhibit periodic releases of significant quantities of flammable gases. Because potential safety issues have been identified with this type of waste behavior, applicable tanks were equipped with instrumentation offering the capability to continuously monitor gases released from them. This document was written to cover three primary areas: (1) describe the current technical basis for requiring flammable gas monitoring, (2) update the technical basis to include knowledge gained from monitoring the tanks over the last three years, (3) provide the criteria for removal of Standard Hydrogen Monitoring System(s) (SHMS) from a waste tank or termination of other flammable gas monitoring activities in the Hanford Tank farms

  19. Flammable Gas Safety Program: analysis of gas sampling probe locations in the SX-farm flammable gas watchlist tanks

    International Nuclear Information System (INIS)

    McLaren, J.M.; Claybrook, S.W.

    1995-09-01

    An analysis was performed to determine the optimum ventilation line up for the AN Tank Farm. The analysis used the postulated maximum historical GRE in tanks AN-103, -104, and -105. Tank AN-104 was found to be limiting. The results of the analysis show that an airflow of 250 cfm through tanks 241-AN-103, -104, and -105 with an airflow of 100 cfm through tanks 241-AN-101, -102, -106, and -107 would be the optimum ventilation lineup

  20. APPLICATIONS OF CFD METHOD TO GAS MIXING ANALYSIS IN A LARGE-SCALED TANK

    International Nuclear Information System (INIS)

    Lee, S; Richard Dimenna, R

    2007-01-01

    The computational fluid dynamics (CFD) modeling technique was applied to the estimation of maximum benzene concentration for the vapor space inside a large-scaled and high-level radioactive waste tank at Savannah River site (SRS). The objective of the work was to perform the calculations for the benzene mixing behavior in the vapor space of Tank 48 and its impact on the local concentration of benzene. The calculations were used to evaluate the degree to which purge air mixes with benzene evolving from the liquid surface and its ability to prevent an unacceptable concentration of benzene from forming. The analysis was focused on changing the tank operating conditions to establish internal recirculation and changing the benzene evolution rate from the liquid surface. The model used a three-dimensional momentum coupled with multi-species transport. The calculations included potential operating conditions for air inlet and exhaust flows, recirculation flow rate, and benzene evolution rate with prototypic tank geometry. The flow conditions are assumed to be fully turbulent since Reynolds numbers for typical operating conditions are in the range of 20,000 to 70,000 based on the inlet conditions of the air purge system. A standard two-equation turbulence model was used. The modeling results for the typical gas mixing problems available in the literature were compared and verified through comparisons with the test results. The benchmarking results showed that the predictions are in good agreement with the analytical solutions and literature data. Additional sensitivity calculations included a reduced benzene evolution rate, reduced air inlet and exhaust flow, and forced internal recirculation. The modeling results showed that the vapor space was fairly well mixed and that benzene concentrations were relatively low when forced recirculation and 72 cfm ventilation air through the tank boundary were imposed. For the same 72 cfm air inlet flow but without forced recirculation

  1. Steady State Structural Analysis of High Pressure Gas Turbine Blade using Finite Element Analysis

    Science.gov (United States)

    Mazarbhuiya, Hussain Mahamed Sahed Mostafa; Murari Pandey, Krishna

    2017-08-01

    In gas turbines the major portion of performance dependency lies upon turbine blade design. Turbine blades experience very high centrifugal, axial and tangential force during power generation. While withstanding these forces blades undergo elongation. Different methods have proposed for better enhancement of the mechanical properties of blade to withstand in extreme condition. Present paper describes the stress and elongation for blades having properties of different materials. Steady state structural analysis have performed in the present work for different materials (In 625, In 718, In 738, In 738 LC, MAR M246, Ni-Cr, Ti-alloy, Ti-Al, Ti-T6, U500). Remarkable finding is that the root of the blade is subjected to maximum stress for all blade materials and the blade made of MAR M246 has less stress and deformation among all other blade materials which can be selected as a suitable material for gas turbine blade.

  2. Analysis and improvement of gas turbine blade temperature measurement error

    International Nuclear Information System (INIS)

    Gao, Shan; Wang, Lixin; Feng, Chi; Daniel, Ketui

    2015-01-01

    Gas turbine blade components are easily damaged; they also operate in harsh high-temperature, high-pressure environments over extended durations. Therefore, ensuring that the blade temperature remains within the design limits is very important. In this study, measurement errors in turbine blade temperatures were analyzed, taking into account detector lens contamination, the reflection of environmental energy from the target surface, the effects of the combustion gas, and the emissivity of the blade surface. In this paper, each of the above sources of measurement error is discussed, and an iterative computing method for calculating blade temperature is proposed. (paper)

  3. Analysis and improvement of gas turbine blade temperature measurement error

    Science.gov (United States)

    Gao, Shan; Wang, Lixin; Feng, Chi; Daniel, Ketui

    2015-10-01

    Gas turbine blade components are easily damaged; they also operate in harsh high-temperature, high-pressure environments over extended durations. Therefore, ensuring that the blade temperature remains within the design limits is very important. In this study, measurement errors in turbine blade temperatures were analyzed, taking into account detector lens contamination, the reflection of environmental energy from the target surface, the effects of the combustion gas, and the emissivity of the blade surface. In this paper, each of the above sources of measurement error is discussed, and an iterative computing method for calculating blade temperature is proposed.

  4. Analysis of engineering cycles power, refrigerating and gas liquefaction plant

    CERN Document Server

    Haywood, R W

    1991-01-01

    Extensively revised, updated and expanded, the fourth edition of this popular text provides a rigorous analytical treatment of modern energy conversion plant. Notable for both its theoretical and practical treatment of conventional and nuclear power plant, and its studies of refrigerating and gas-liquefaction plant. This fourth edition now includes material on topics of increasing concern in the fields of energy 'saving' and reduction of environmental pollution. This increased coverage deals specifically with the following areas: CHP (cogeneration) plant, studies of both gas and coal burning p

  5. An Analysis of Policy Issues in Natural Gas Industry Restructuring

    Energy Technology Data Exchange (ETDEWEB)

    Seo, J.K. [Korea Energy Economics Institute, Euiwang (Korea)

    2001-12-01

    This report explores controversial issues and problems that could emerge in the process of implementing the government's restructuring plan for natural gas industry and aims to suggest policy directions regarding the restructuring. To begin with, it examines current conditions surrounding natural gas industry including domestic demand and supply conditions, world LNG market trend, structural changes of the industry in OECD countries, possibilities of introducing effective competition and assignment of existing import contracts. In doing so, we probe whether the direction of the natural gas industry restructuring is proper and suggest that the results be reflected when a more detailed restructuring implementation plan is formulated. Also, this report suggests possible schemes related to major institutional changes expected by the basic restructuring plan and the detailed restructuring implementation plan announced by the government. First, it presents several alternative ways to properly divide up the import/wholesales section of Korea Gas Corporation. Second, it examines critical issues such as the method of using gas supply facilities and gas balancing mechanism, and presents adoptable alternatives for each issue. These issues constitute the core of network and market operation rules which need to be in place when adopting an open access system, which in turn is a prerequisite for sales competition. Third, the report examines price systems, including gas commodity pricing and rate-making design for transportation service, by first anticipating the direction of changes in gas rate regulation. Specifically, it presents possible ways to design the service rate for each function of pipeline network and import terminals, and discusses controversial issues in determining total cost-of-service and allocating the cost-of-service to each functional service offered such as distance-related rates, interruptible service rate. Lastly, in relation to the opening of retail

  6. Parametric economic analysis of natural gas reburn technologies. Topical report, June 1991-June 1992

    International Nuclear Information System (INIS)

    Bluestein, J.

    1992-06-01

    The report presents a parametric economic analysis of natural gas reburn technologies used for control of nitrogen oxides emissions in coal-fired utility boilers. It is a competitive assessment of the economics of gas reburn performed in the context of regulatory requirements and competing conventional technologies. The reburn technologies examined are basic gas reburn, reburn with sorbent injection and advanced gas reburn. The analysis determined the levelized costs of these technologies in $/ton of NOx removed with respect to a gas-coal price differential in $/MMBtu of energy input. For those niches in which reburn was less economical, a breakeven capital cost analysis was carried out to determine the R ampersand D goals which would make reburn more cost competitive

  7. On-line non-contact gas analysis

    DEFF Research Database (Denmark)

    Fateev, Alexander; Clausen, Sønnik

    , and good agreement has been found for NO (e.g. deviations of 1-5% for NO at 1200 °C). Practical highresolution measurements at the AVV2 boiler are analysed, and detection limits for the NO are discussed. The developed tools and results will be used in the future projects, e.g. fast measurements of the gas...

  8. Analysis of oxygen-enhanced combustion of gas power cycle

    Energy Technology Data Exchange (ETDEWEB)

    Maidana, Cristiano Frandalozo; Carotenuto, Adriano; Schneider, Paulo Smith [Universidade Federal do Rio Grande do Sul (GESTE/UFRGS), Porto Alegre, RS (Brazil). Grupo de Estudos Termicos e Energeticos], E-mails: cristiano.maidana@ufrgs.br, pss@mecanica.ufrgs.br

    2010-07-01

    The majority of combustion processes use air as oxidant, roughly taken as 21% O{sub 2} and 79% N{sub 2}, by volume. In many cases, these processes can be enhanced by using an oxidant that contains higher proportion of O{sub 2} than in air. This is known as oxygen-enhanced combustion or OEC, and can bring important benefits like higher thermal efficiencies, lower exhaust gas volumes, higher heat transfer efficiency, reduction fuel consumption, reduced equipment costs and substantially pollutant emissions reduction. Within this scenario, this paper aims to investigate the influence of 21-30% oxygen concentration on the performance of a air-fired natural gas fueled power plant. This power plant operates under a Brayton cycle with models with the help of an air flow splitter after the compressor output in order to dose the oxygen rate of combustion and to keep the flue gas intake of the turbine at a prescribed temperature. Simulations shows that the enhancing of the oxidant stream reduced fuel consumption of about 10%, driven by higher adiabatic flame temperatures, which improves thermal and heat transfer efficiencies. A conclusion obtained is that the use of oxygen in higher proportions can be a challenge to retrofit existing air-fired natural gas power turbine cycles, because of the technological limitation of its materials with higher flame temperatures. (author)

  9. Gas Chromatography-Mass Spectrometric Analysis of Nematicidal ...

    African Journals Online (AJOL)

    Purpose: To investigate the chemical composition and nematicidal activity of the essential oil of. Valeriana amurensis ... Methods: The essential oil of V. amurensis roots was obtained by hydrodistillation and analyzed by gas chromatography (GC) ..... Aβ1-40 and Caspase-3 in Alzheimer's disease model rat's brain. J Chin ...

  10. Analysis of volatile phase transport in soils using natural radon gas as a tracer

    International Nuclear Information System (INIS)

    Chen, C.; Thomas, D.M.

    1992-01-01

    We have conducted a field study of soil gas transport processes using radon gas as a naturally occurring tracer. The experiment monitored soil gas radon activity, soil moisture, and soil temperature at three depths in the shallow soil column; barometric pressure, rainfall and wind speed were monitored at the soil surface. Linear and multiple regression analysis of the data sets has shown that the gas phase radon activities under natural environmental conditions are influenced by soil moisture content, barometric pressure variations, soil temperature and soil structure. The effect of wind speed on subsurface radon activities under our field conditions has not been demonstrated

  11. Gas stream analysis using voltage-current time differential operation of electrochemical sensors

    Science.gov (United States)

    Woo, Leta Yar-Li; Glass, Robert Scott; Fitzpatrick, Joseph Jay; Wang, Gangqiang; Henderson, Brett Tamatea; Lourdhusamy, Anthoniraj; Steppan, James John; Allmendinger, Klaus Karl

    2018-01-02

    A method for analysis of a gas stream. The method includes identifying an affected region of an affected waveform signal corresponding to at least one characteristic of the gas stream. The method also includes calculating a voltage-current time differential between the affected region of the affected waveform signal and a corresponding region of an original waveform signal. The affected region and the corresponding region of the waveform signals have a sensitivity specific to the at least one characteristic of the gas stream. The method also includes generating a value for the at least one characteristic of the gas stream based on the calculated voltage-current time differential.

  12. Risk Analysis using Corrosion Rate Parameter on Gas Transmission Pipeline

    Science.gov (United States)

    Sasikirono, B.; Kim, S. J.; Haryadi, G. D.; Huda, A.

    2017-05-01

    In the oil and gas industry, the pipeline is a major component in the transmission and distribution process of oil and gas. Oil and gas distribution process sometimes performed past the pipeline across the various types of environmental conditions. Therefore, in the transmission and distribution process of oil and gas, a pipeline should operate safely so that it does not harm the surrounding environment. Corrosion is still a major cause of failure in some components of the equipment in a production facility. In pipeline systems, corrosion can cause failures in the wall and damage to the pipeline. Therefore it takes care and periodic inspections or checks on the pipeline system. Every production facility in an industry has a level of risk for damage which is a result of the opportunities and consequences of damage caused. The purpose of this research is to analyze the level of risk of 20-inch Natural Gas Transmission Pipeline using Risk-based inspection semi-quantitative based on API 581 associated with the likelihood of failure and the consequences of the failure of a component of the equipment. Then the result is used to determine the next inspection plans. Nine pipeline components were observed, such as a straight pipes inlet, connection tee, and straight pipes outlet. The risk assessment level of the nine pipeline’s components is presented in a risk matrix. The risk level of components is examined at medium risk levels. The failure mechanism that is used in this research is the mechanism of thinning. Based on the results of corrosion rate calculation, remaining pipeline components age can be obtained, so the remaining lifetime of pipeline components are known. The calculation of remaining lifetime obtained and the results vary for each component. Next step is planning the inspection of pipeline components by NDT external methods.

  13. Natural selection promotes antigenic evolvability

    NARCIS (Netherlands)

    Graves, C.J.; Ros, V.I.D.; Stevenson, B.; Sniegowski, P.D.; Brisson, D.

    2013-01-01

    The hypothesis that evolvability - the capacity to evolve by natural selection - is itself the object of natural selection is highly intriguing but remains controversial due in large part to a paucity of direct experimental evidence. The antigenic variation mechanisms of microbial pathogens provide

  14. Strategic analysis on establishing a natural gas trading hub in China

    Directory of Open Access Journals (Sweden)

    Xiaoguang Tong

    2014-12-01

    Full Text Available Since 2010, the LNG importing price premium in the Asia–Pacific markets has become increasingly high, generating great effects on the economic development in China. In addition, the natural gas dependence degree is expanding continuously, making it extremely urgent to establish a natural gas trading hub in China, with the aim to ensure national energy security, to gain the pricing power, and to build the regional benchmark prices. Through a comparative analysis of internal strength/weakness and external competitiveness, we concluded that with intensively-issued supporting policies on the natural gas sector, the initiation of spot and futures markets, the rapid growth of gas production and highly-improved infrastructures, as well as Shanghai's advantageous location, China has more advantages in establishing an Asian Natural Gas Trading Hub than other counties like Singapore, Japan and Malaysia. Moreover, based on the SWOT (strength, weakness, opportunity and threat and the marketization process analysis, the following strategies were presented: to impel the establishment of a natural gas trading hub depending on the gas supply condition, to follow the policies to complete the gas storage system, to form regional communities by taking comparative advantages, and to reinforce the marketization reform and regulation system establishment with foreign experiences for reference. This study rationalized the necessity and practicality of establishing a natural gas trading hub in China and will help China make a proper decision and find a periodical strategic path in this sector.

  15. Economic analysis of using above ground gas storage devices for compressed air energy storage system

    Science.gov (United States)

    Liu, Jinchao; Zhang, Xinjing; Xu, Yujie; Chen, Zongyan; Chen, Haisheng; Tan, Chunqing

    2014-12-01

    Above ground gas storage devices for compressed air energy storage (CAES) have three types: air storage tanks, gas cylinders, and gas storage pipelines. A cost model of these gas storage devices is established on the basis of whole life cycle cost (LCC) analysis. The optimum parameters of the three types are determined by calculating the theoretical metallic raw material consumption of these three devices and considering the difficulties in manufacture and the influence of gas storage device number. The LCCs of the three types are comprehensively analyzed and compared. The result reveal that the cost of the gas storage pipeline type is lower than that of the other two types. This study may serve as a reference for designing large-scale CAES systems.

  16. Relating landfill gas emissions to atmospheric pressure using numerical modeling and state-space analysis

    DEFF Research Database (Denmark)

    Poulsen, T.G.; Christophersen, Mette; Moldrup, P.

    2003-01-01

    were applied: (I) State-space analysis was used to identify relations between gas flux and short-term (hourly) variations in atmospheric pressure. (II) A numerical gas transport model was fitted to the data and used to quantify short-term impacts of variations in atmospheric pressure, volumetric soil......-water content, soil gas permeability, soil gas diffusion coefficients, and biological CH4 degradation rate upon landfill gas concentration and fluxes in the soil. Fluxes and concentrations were found to be most sensitive to variations in volumetric soil water content, atmospheric pressure variations and gas...... permeability whereas variations in CH4 oxidation rate and molecular coefficients had less influence. Fluxes appeared to be most sensitive to atmospheric pressure at intermediate distances from the landfill edge. Also overall CH4 fluxes out of the soil over longer periods (years) were largest during periods...

  17. Patent analysis to identify shale gas development in China and the United States

    International Nuclear Information System (INIS)

    Lee, Woo Jin; Sohn, So Young

    2014-01-01

    Shale gas has become an increasingly important form of hydrocarbon energy, and related technologies reflect the geographical characteristics of the countries where the gas is extracted and stored. The United States (U.S.) produces most of the world’s shale gas, while China has the world’s largest shale gas reserves. In this research, we focused on identifying the trends in shale-gas related technologies registered to the United States Patent and Trademark Office (USPTO) and to the State Intellectual Property Office of the People’s Republic of China (SIPO) respectively. To cluster shale-gas related technologies, we text-mined the abstracts of patent specifications. It was found that in the U.S., the key advanced technologies were related to hydraulic fracturing, horizontal drilling, and slick water areas, whereas China had a focus on proppants. The results of our study are expected to assist energy experts in designing energy policies related to technology importation. - Highlights: • We analyzed shale gas-related patent applications in the USPTO and SIPO. • We clustered shale gas patents by text mining patent abstract. • Differences were observed in shale gas technologies developed in the U.S. and China. • We proposed the policies of shale gas exploration and development based on patent analysis

  18. Using size distribution analysis to forecast natural gas resources in Asia Pacific

    International Nuclear Information System (INIS)

    Aguilera, Roberto F.; Ripple, Ronald D.

    2011-01-01

    Highlights: → We estimate the total endowment of conventional natural gas in Asia Pacific. → Includes volumes in previously unassessed provinces. → Endowment distributed across countries to show where volumes are most likely to be found. → A breakdown between offshore versus onshore resources is also estimated. → We find there is a significant natural gas endowment in the region. -- Abstract: Increasing energy consumption in Asia Pacific will largely be met by fossil fuels. Natural gas production in the region presently ranks behind that of oil and coal. However, the abundance of gas could lead to a significant gas market share increase in the energy mix. The purpose of this paper is to estimate the total endowment of conventional gas in Asia Pacific. This is carried out with a Variable Shape Distribution (VSD) model that forecasts volumes in provinces that have not been previously evaluated. The endowment is then distributed across countries to show where volumes are most likely to be found. A breakdown between offshore versus onshore resources is also estimated. The results of the analysis show there is a significant gas endowment. The estimated distribution across countries and onshore/offshore areas provides insight into the relative economics of gas production, as well as a basis for potential investment decisions. With appropriate energy policies, it may be possible to tap the vast gas potential in Asia Pacific. Considering gas may be the most abundant, inexpensive, and clean fossil fuel, the outcome would be increased energy security and a low carbon economy.

  19. Assessment of oil weathering by gas chromatography-mass spectrometry, time warping and principal component analysis

    DEFF Research Database (Denmark)

    Malmquist, Linus M.V.; Olsen, Rasmus R.; Hansen, Asger B.

    2007-01-01

    weathering state and to distinguish between various weathering processes is investigated and discussed. The method is based on comprehensive and objective chromatographic data processing followed by principal component analysis (PCA) of concatenated sections of gas chromatography–mass spectrometry...

  20. Off-Gas Analysis During the Vitrification of Hanford Radioactive Waste Samples

    International Nuclear Information System (INIS)

    Ha, B.C.; Ferrara, D.M.; Crawford, C.L.; Choi, A.S.; Bibler, N.E.

    1998-01-01

    This paper describes the off-gas analysis of samples collected during the radioactive vitrification experiments. Production and characterization of the Hanford waste-containing LAW and HAW glasses are presented in related reports from this conference

  1. (N+1)-dimensional Lorentzian evolving wormholes supported by polytropic matter

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, Mauricio [Universidad del Bio-Bio, Departamento de Fisica, Facultad de Ciencias, Concepcion (Chile); Arostica, Fernanda; Bahamonde, Sebastian [Universidad de Concepcion, Departamento de Fisica, Concepcion (Chile)

    2013-08-15

    In this paper we study (N+1)-dimensional evolving wormholes supported by energy satisfying a polytropic equation of state. The considered evolving wormhole models are described by a constant redshift function and generalizes the standard flat Friedmann-Robertson-Walker spacetime. The polytropic equation of state allows us to consider in (3+1)-dimensions generalizations of the phantom energy and the generalized Chaplygin gas sources. (orig.)

  2. Continuum removed band depth analysis for detecting the effects of natural gas, methane and ethane on maize reflectance

    NARCIS (Netherlands)

    Noomen, M.F.; Skidmore, A.K.; Meer, van der F.D.; Prins, H.H.T.

    2006-01-01

    It is known that natural gas in the soil affects vegetation health, which may be detected through analysis of reflectance spectra. Since natural gas is invisible, changes in the vegetation could potentially indicate gas leakage. Although it is known that gas in soil affects plant reflectance, the

  3. Gas turbine cooling modeling - Thermodynamic analysis and cycle simulations

    Energy Technology Data Exchange (ETDEWEB)

    Jordal, Kristin

    1999-02-01

    Considering that blade and vane cooling are a vital point in the studies of modern gas turbines, there are many ways to include cooling in gas turbine models. Thermodynamic methods for doing this are reviewed in this report, and, based on some of these methods, a number of model requirements are set up and a Cooled Gas Turbine Model (CGTM) for design-point calculations of cooled gas turbines is established. Thereafter, it is shown that it is possible to simulate existing gas turbines with the CGTM. Knowledge of at least one temperature in the hot part of the turbine (TET, TRIT or possibly TIT) is found to be vital for a complete heat balance over the turbine. The losses, which are caused by the mixing of coolant and main flow, are in the CGTM considered through a polytropic efficiency reduction factor S. Through the study of S, it can be demonstrated that there is more to gain from coolant reduction in a small and/or old turbine with poor aerodynamics, than there is to gain in a large, modern turbine, where the losses due to interaction between coolant and main flow are, relatively speaking, small. It is demonstrated, at the design point (TET=1360 deg C, {pi}=20) for the simple-cycle gas turbine, that heat exchanging between coolant and fuel proves to have a large positive impact on cycle efficiency, with an increase of 0.9 percentage points if all of the coolant passes through the heat exchanger. The corresponding improvement for humidified coolant is 0.8 percentage points. A design-point study for the HAT cycle shows that if all of the coolant is extracted after the humidification tower, there is a decrease in coolant requirements of 7.16 percentage points, from 19.58% to 12.52% of the compressed air, and an increase in thermal efficiency of 0.46 percentage points, from 53.46% to 53.92%. Furthermore, it is demonstrated with a TET-parameter variation, that the cooling of a simple-cycle gas turbine with humid air can have a positive effect on thermal efficiency

  4. Thermodynamical cycle analysis of gas in a thermocompressor

    Energy Technology Data Exchange (ETDEWEB)

    Arques, P.

    1998-07-01

    A thermocompressor is a compressor that transforms the heat of a source into an energy of pressure without intermediate mechanical work. It is a Stirling engine simplification into a driven machine for which the piston that provides the power has been suppressed. This thermocompressor comprises a free piston displacer that separates cold and hot gas. The simulation takes into account the movement of the piston, heat transfers and variable mass with the time. The thermocompressor is a compressor of gas that works between one hot and one cold source. This compressor has neither crankshaft nor connecting rod assembly. In this paper, the author presents some results concerning this type of compressor. The ratio of pressures that it is possible to obtain is a function of the ratio of hot and cold source temperatures and of the extreme volume ratio. The global efficiency of the cycle with the regenerator go up by an maximum independent of the regenerator efficiency. The open cycle is executed in a thermocompressor that has a free piston separating cold and hot gas, intake and exhaust valves and the regenerator. The thermocompressor compression efficiency decreases when the volumetric ratio increases. For the gas, it is therefore desirable to have an extreme volume ratio closest to 1. In the paper, the author presents : Actual and calculated evolution of the free piston velocity compared to the theoretical evolution obtained by calculation with a pressure linearisation; friction influence between piston and cylinder; the differential equation of the movement of the piston; the period of pulsation of the piston; influence of the piston adiabaticity. By analytical study followed by an actual simulation, the author shows that: the regenerator efficiency has a very strong influence on the engine efficiency; taking into account the hot source temperature, the choice of volumes has affects the efficiency, consequences which must be taken into account.

  5. Optimal Energy Consumption Analysis of Natural Gas Pipeline

    Science.gov (United States)

    Liu, Enbin; Li, Changjun; Yang, Yi

    2014-01-01

    There are many compressor stations along long-distance natural gas pipelines. Natural gas can be transported using different boot programs and import pressures, combined with temperature control parameters. Moreover, different transport methods have correspondingly different energy consumptions. At present, the operating parameters of many pipelines are determined empirically by dispatchers, resulting in high energy consumption. This practice does not abide by energy reduction policies. Therefore, based on a full understanding of the actual needs of pipeline companies, we introduce production unit consumption indicators to establish an objective function for achieving the goal of lowering energy consumption. By using a dynamic programming method for solving the model and preparing calculation software, we can ensure that the solution process is quick and efficient. Using established optimization methods, we analyzed the energy savings for the XQ gas pipeline. By optimizing the boot program, the import station pressure, and the temperature parameters, we achieved the optimal energy consumption. By comparison with the measured energy consumption, the pipeline now has the potential to reduce energy consumption by 11 to 16 percent. PMID:24955410

  6. Smell of danger: an analysis of LP-gas odorization

    Energy Technology Data Exchange (ETDEWEB)

    Cain, W.S.; Turk, A.

    1985-03-01

    LP-gas derives warning properties from the odorants ethyl mercaptan or thiophane. Laboratory tests have implied that the average person has the ability to smell the odors before leaking LP-gas reaches one-fifth its lower limit of flammability. Generally, however, laboratory tests ignore or discard persons with a poor sense of smell, especially the elderly and persons with certain types of hyposmia. Some persons who apparently can smell the warning agents when directed may otherwise fail to notice or identify them. Elderly men seem particularly vulnerable to instances of incidental anosmia and olfactory agnosia. Psychophysical testing of the warning agents has been rather unsophisticated. There exists neither a standard protocol for testing nor adequate specification of the perceptual properties that might make one warning agent better than another. Without such developments, improvement in warning agents will fail to occur. Possible improvements include increases in concentration, the use of blends to insure more uniform delivery of agent and, to decrease the perceptual vulnerability of relatively insensitive people, use of agents with favorable psychophysical (stimulus-response) functions and use of agents with favorable adaptation characteristics. Even without a change in existing products, it seems advisable to learn more about the vulnerability of LP-gas users and to employ educational means to reduce risks.

  7. Analysis of hollow fibre membrane systems for multicomponent gas separation

    KAUST Repository

    Khalilpour, Rajab

    2013-02-01

    This paper analysed the performance of a membrane system over key design/operation parameters. A computation methodology is developed to solve the model of hollow fibre membrane systems for multicomponent gas feeds. The model represented by a nonlinear differential algebraic equation system is solved via a combination of backward differentiation and Gauss-Seidel methods. Natural gas sweetening problem is investigated as a case study. Model parametric analyses of variables, namely feed gas quality, pressure, area, selectivity and permeance, resulted in better understanding of operating and design optima. Particularly, high selectivities and/or permeabilities are shown not to be necessary targets for optimal operation. Rather, a medium selectivity (<60 in the given example) combined with medium permeance (∼300-500×10-10mol/sm2Pa in the given case study) is more advantageous. This model-based membrane systems engineering approach is proposed for the synthesis of efficient and cost-effective multi-stage membrane networks. © 2012 The Institution of Chemical Engineers.

  8. Analysis of Mechanical Seals for High-Speed Centrifugal Gas Compressors

    OpenAIRE

    K.N. Nwaigwe; P.E. Ugwuoke; E.E. Anyanwu; D.P.S. Abam

    2012-01-01

    A study aimed at seal selection efficiency for centrifugal pumps in the oil and gas industry is presented. A detailed analysis of mechanical seals in use in exploration and production activities of the oil and gas sector was undertaken. The approach of analysis was using seal design equations as mathematical models for simulating the performance of the mechanical seal. The results showed a mechanical seal with balance value of 0.5, an increased surface area between mating surfaces; provided w...

  9. Metallurgical analysis of high pressure gas pipelines rupture

    International Nuclear Information System (INIS)

    Hasan, F.; Ahmed, F.

    2007-01-01

    On 6 July 2004, two parallel-running gas pipelines (18-inch and 24-inch diameters), in the main transmission network of SNGPL (a gas company in Pakistan) were ruptured. The ruptures occurred in the early hours of the morning about 8 miles downstream of the compressor station AC-4. The ruptures were indicated by the increased gas flow at the outlet of AC-4 (1), first at about 0648 hours and then again about 20 minutes later. The gas escaping from the ruptured lines had caught fire, and the flames had also 'affected' a third parallel-running pipeline of 30-inch diameter, lying next to the 24-inch line. The metallurgical examination of the two ruptured lines showed that the 24-inch line was ruptured with the help of an explosive device that had been placed on the underside of the pipe. An examination of the 18-inch line showed that this pipe had failed as a result of the heating of the pipe-wall, presumably, by the flame emanating from the 24-inch line. These two observations clearly suggested that the 24-inch line was the first to rupture (by explosives), and the fire following this rupture had heated the 18-inch pipe to a temperature where its yield strength was unable to support the inside gas pressure. The 20 minutes time interval between the two ruptures was obviously the time taken by the 18 inch pipe to be heated upto the level where it started to yield. The 30-inch line lying next to the 24-inch line was affected to the extent that its coating had been burnt-off over a length of about 40-50 feet. However, the pipe did not exhibit any signs of deshaping or deformation what-so-ever. A replica metallographic examination indicated that the microstructure of the pipe was not measurably affected by the heat. It was thus decided not to replace the affected part of the 30-inch pipe, but only to re-coat this affected portion. (author)

  10. The gas market opens out to competition: how will the French system of distributions evolve?; Ouverture a la concurrence du marche du gaz: quelle evolution pour le systeme francais des concessions de distribution?

    Energy Technology Data Exchange (ETDEWEB)

    Carbonnier, R. [Strasbourg-3 Universite, Robert Schuman, 67 (France)]|[Strasbourg-1 Univ. Louis Pasteur, 67 (France)

    1998-10-01

    Th public distribution of natural gas in France is organised around a system of franchises allocated by the communes to a unique designated distributor (Gaz de France in most cases). This system, which was recently eased by a legislative provision, seems to have an uncertain future faced with the opening of competition that is encouraged by the European authorities and with the demands of some local communities which would like to lay a greater role in the future organisational plan for gas. This article looks at the possible evolutions, from the reactivation of franchises to their complete disappearance. (author)

  11. Just fracking: a distributive environmental justice analysis of unconventional gas development in Pennsylvania, USA

    Science.gov (United States)

    Clough, Emily; Bell, Derek

    2016-02-01

    This letter presents a distributive environmental justice analysis of unconventional gas development in the area of Pennsylvania lying over the Marcellus Shale, the largest shale gas formation in play in the United States. The extraction of shale gas using unconventional wells, which are hydraulically fractured (fracking), has increased dramatically since 2005. As the number of wells has grown, so have concerns about the potential public health effects on nearby communities. These concerns make shale gas development an environmental justice issue. This letter examines whether the hazards associated with proximity to wells and the economic benefits of shale gas production are fairly distributed. We distinguish two types of distributive environmental justice: traditional and benefit sharing. We ask the traditional question: are there a disproportionate number of minority or low-income residents in areas near to unconventional wells in Pennsylvania? However, we extend this analysis in two ways: we examine income distribution and level of education; and we compare before and after shale gas development. This contributes to discussions of benefit sharing by showing how the income distribution of the population has changed. We use a binary dasymetric technique to remap the data from the 2000 US Census and the 2009-2013 American Communities Survey and combine that data with a buffer containment analysis of unconventional wells to compare the characteristics of the population living nearer to unconventional wells with those further away before and after shale gas development. Our analysis indicates that there is no evidence of traditional distributive environmental injustice: there is not a disproportionate number of minority or low-income residents in areas near to unconventional wells. However, our analysis is consistent with the claim that there is benefit sharing distributive environmental injustice: the income distribution of the population nearer to shale gas wells

  12. EVOLVE : International Conference

    CERN Document Server

    Deutz, Andre; Schuetze, Oliver; Bäck, Thomas; Tantar, Emilia; Tantar, Alexandru-Adrian; Moral, Pierre; Legrand, Pierrick; Bouvry, Pascal; Coello, Carlos

    2013-01-01

    Numerical and computational methods are nowadays used in a wide range of contexts in complex systems research, biology, physics, and engineering.  Over the last decades different methodological schools have emerged with emphasis on different aspects of computation, such as nature-inspired algorithms, set oriented numerics, probabilistic systems and Monte Carlo methods. Due to the use of different terminologies and emphasis on different aspects of algorithmic performance there is a strong need for a more integrated view and opportunities for cross-fertilization across particular disciplines. These proceedings feature 20 original publications from distinguished authors in the cross-section of computational sciences, such as machine learning algorithms and probabilistic models, complex networks and fitness landscape analysis, set oriented numerics and cell mapping, evolutionary multiobjective optimization, diversity-oriented search, and the foundations of genetic programming algorithms. By presenting cutting ed...

  13. A simulation approach for analysis of short-term security of natural gas supply in Colombia

    International Nuclear Information System (INIS)

    Villada, Juan; Olaya, Yris

    2013-01-01

    Achieving security of gas supply implies diversifying gas sources, while having enough supply, transportation, and storage capacity to meet demand peaks and supply interruptions. Devising a strategy for securing gas supply is not straightforward because gas supply depends on complex interactions of production, demand and infrastructure, and it is exposed to economic, regulatory, political, environmental and technical risks. To address this complexity, we propose a simulation approach that replicates the structure of the gas supply chain, including transportation constraints and demand fluctuations. We build and calibrate a computer model for the Colombian gas sector, and run the model to assess the impact of expanding transportation capacity and increasing market flexibility on the security of supply. Our analysis focuses on the operation and planned and proposed expansions of the transportation infrastructure because adequate regulation and development of this infrastructure can contribute to increase the security of supply in the gas sector. We find that proposed import facilities, specifically LNG import terminals at Buenaventura, increase system's security under the current market structure. - Highlights: ► We build a simulation model for analyzing natural gas trade in Colombia. ► The model captures the structure of the gas network and on market rules. ► We simulate investment decisions to increase short-term security of supply. ► Securing supply would need LNG imports and expansion of pipeline capacity.

  14. Natural gas to improve energy security in Small Island Developing States: A techno-economic analysis

    Directory of Open Access Journals (Sweden)

    Pravesh Raghoo

    Full Text Available There is a paucity of studies on natural gas-based energy production in Small Island Developing States (SIDS even though technological improvements today are likely to make the application of natural gas more and more feasible. The development of natural gas in some of the regions of the Pacific, Africa, Indian Ocean and Caribbean attracts nearby countries and the coming up of the compressed natural gas (CNG technology which can serve regional markets are two motivations for SIDS to develop natural gas-based energy provision. A third factor concerns long-term energy security. Due to continued reliance on fossil fuels and slow uptake of renewable energy, there is a need to diversify SIDS’ energy mix for a sustainable electricity industry. Comparing the opportunities and constraints of liquefied natural gas (LNG and compressed natural gas (CNG in a SIDS-specific context, this paper discusses how to improve the integration of natural gas in prevailing energy regimes in SIDS as an alternative fuel to oil and complementary to renewable energy sources. To illustrate feasibility in practice, a techno-economic analysis is carried out using the island of Mauritius as an example. Keywords: Energy security, Natural gas, Small Island Developing States

  15. Technical and Feasibility Analysis of Gasoline and Natural Gas Fuelled Vehicles

    Directory of Open Access Journals (Sweden)

    Charalambos Chasos

    2014-03-01

    Full Text Available There is recent interest for the utilisation of natural gas for empowering the internal combustion engines (ICE of vehicles. The production of novel natural gas ICE for vehicles, as well as the conversion of existing gasoline fuelled ICE of vehicles to natural gas fuelled ICE are new technologies which require to be analysed and assessed. The objective of the present study is to examine the adaptation of natural gas as vehicle fuel and carry out a technical analysis and an economical feasibility analysis of the two types of ICE vehicles, namely gasoline and natural gas fuelled vehicles. The technical model uses the physical properties of the two fuels and the performance factors of internal combustion engines including brake thermal efficiency. The resulting exhaust gas emissions are also estimated by the technical model using combustion calculations which provide the expected levels of exhaust gas emissions. Based on the analysis with the technical model, comparisons of the two types of engines are performed. Furthermore, the estimated performance characteristics of the two types of engines, along with local statistical data on annual fuel imports and annual fuel consumption for transportation and data on the vehicles fleet for the case study of Cyprus are used as input in the economical model. For the base year 2013, data of natural gas price is also used in the economical model. The economical model estimates the capital cost, the carbon dioxide emissions avoidance of fines, the net present value and the internal rate of return of the investment of large scale adaptation of natural gas fuelled vehicles for the case study. From the results and comparisons, conclusions are drawn and recommendations are provided for the adaptation of natural gas vehicles which can provide improved performance with reduced pollutant emissions.

  16. Probabilistic Steady-State Operation and Interaction Analysis of Integrated Electricity, Gas and Heating Systems

    Directory of Open Access Journals (Sweden)

    Lun Yang

    2018-04-01

    Full Text Available The existing studies on probabilistic steady-state analysis of integrated energy systems (IES are limited to integrated electricity and gas networks or integrated electricity and heating networks. This paper proposes a probabilistic steady-state analysis of integrated electricity, gas and heating networks (EGH-IES. Four typical operation modes of an EGH-IES are presented at first. The probabilistic energy flow problem of the EGS-IES considering its operation modes and correlated uncertainties in wind/solar power and electricity/gas/heat loads is then formulated and solved by the Monte Carlo method based on Latin hypercube sampling and Nataf transformation. Numerical simulations are conducted on a sample EGH-IES working in the “electricity/gas following heat” mode to verify the probabilistic analysis proposed in this paper and to study the effects of uncertainties and correlations on the operation of the EGH-IES, especially uncertainty transmissions among the subnetworks.

  17. Severe Accident Analysis for Combustible Gas Risk Evaluation inside CFVS

    International Nuclear Information System (INIS)

    Lee, NaRae; Lee, JinYong; Bang, YoungSuk; Lee, DooYong; Kim, HyeongTaek

    2015-01-01

    The purpose of this study is to identify the composition of gases discharged into the containment filtered venting system by analyzing severe accidents. The accident scenarios which could be significant with respect to containment pressurization and hydrogen generation are derived and composition of containment atmosphere and possible discharged gas mixtures are estimated. In order to ensure the safety of the public and environment, the ventilation system should be designed properly by considering discharged gas flow rate, aerosol loads, radiation level, etc. One of considerations to be resolved is the risk due to combustible gas, especially hydrogen. Hydrogen can be generated largely by oxidation of cladding and decomposition of concrete. If the hydrogen concentration is high enough and other conditions like oxygen and steam concentration is met, the hydrogen can burn, deflagrate or detonate, which result in the damage the structural components. In particularly, after Fukushima accident, the hydrogen risk has been emphasized as an important contributor threatening the integrity of nuclear power plant during the severe accident. These results will be used to analyze the risk of hydrogen combustion inside the CFVS as boundary conditions. Severe accident simulation results are presented and discussed qualitatively with respect to hydrogen combustion. The hydrogen combustion risk inside of the CFVS has been examined qualitatively by investigating the discharge flow characteristics. Because the composition of the discharge flow to CFVS would be determined by the containment atmosphere, the severe accident progression and containment atmosphere composition have been investigated. Due to PAR operation, the hydrogen concentration in the containment would be decreased until the oxygen is depleted. After the oxygen is depleted, the hydrogen concentration would be increased. As a result, depending on the vent initiation timing (i.e. vent initiation pressure), the important

  18. Severe Accident Analysis for Combustible Gas Risk Evaluation inside CFVS

    Energy Technology Data Exchange (ETDEWEB)

    Lee, NaRae; Lee, JinYong; Bang, YoungSuk; Lee, DooYong [FNC Technology Co. Ltd., Yongin (Korea, Republic of); Kim, HyeongTaek [KHNP-Central Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The purpose of this study is to identify the composition of gases discharged into the containment filtered venting system by analyzing severe accidents. The accident scenarios which could be significant with respect to containment pressurization and hydrogen generation are derived and composition of containment atmosphere and possible discharged gas mixtures are estimated. In order to ensure the safety of the public and environment, the ventilation system should be designed properly by considering discharged gas flow rate, aerosol loads, radiation level, etc. One of considerations to be resolved is the risk due to combustible gas, especially hydrogen. Hydrogen can be generated largely by oxidation of cladding and decomposition of concrete. If the hydrogen concentration is high enough and other conditions like oxygen and steam concentration is met, the hydrogen can burn, deflagrate or detonate, which result in the damage the structural components. In particularly, after Fukushima accident, the hydrogen risk has been emphasized as an important contributor threatening the integrity of nuclear power plant during the severe accident. These results will be used to analyze the risk of hydrogen combustion inside the CFVS as boundary conditions. Severe accident simulation results are presented and discussed qualitatively with respect to hydrogen combustion. The hydrogen combustion risk inside of the CFVS has been examined qualitatively by investigating the discharge flow characteristics. Because the composition of the discharge flow to CFVS would be determined by the containment atmosphere, the severe accident progression and containment atmosphere composition have been investigated. Due to PAR operation, the hydrogen concentration in the containment would be decreased until the oxygen is depleted. After the oxygen is depleted, the hydrogen concentration would be increased. As a result, depending on the vent initiation timing (i.e. vent initiation pressure), the important

  19. Modeling and analysis of the Rimfire gas switch

    International Nuclear Information System (INIS)

    Gahl, John M.; Kemp, Mark A.; Struve, Kenneth William; Curry, Randy D.; McDonald, Ken F.

    2005-01-01

    Many accelerators at Sandia National Laboratories utilize the Rimfire gas switch for high-voltage, high-power switching. Future accelerators will have increased performance requirements for switching elements. When designing improved versions of the Rimfire switch, there is a need for quick and accurate simulation of the electrical effects of geometry changes. This paper presents an advanced circuit model of the Rimfire switch that can be used for these simulations. The development of the model is shown along with comparisons to past models and experimental results.

  20. Analysis of artificial fireplace logs by high temperature gas chromatography.

    Science.gov (United States)

    Kuk, Raymond J

    2002-11-01

    High temperature gas chromatography is used to analyze the wax of artificial fireplace logs (firelogs). Firelogs from several different manufacturers are studied and compared. This study shows that the wax within a single firelog is homogeneous and that the wax is also uniform throughout a multi-firelog package. Different brands are shown to have different wax compositions. Firelogs of the same brand, but purchased in different locations, also have different wax compositions. With this information it may be possible to associate an unknown firelog sample to a known sample, but a definitive statement of the origin cannot be made.

  1. Improvement of gas chromatographic analysis for organic acids and ...

    African Journals Online (AJOL)

    Yomi

    2010-08-27

    Aug 27, 2010 ... and ethanol fermentation by using the anaerobic bacterium. Clostridium ... GC analysis. Standard solution for GC analysis consisted of acetic acid (Sigma-. Aldrich ... Microorganism and inoculum preparation. C. beijerinckii ...

  2. Thermal performance of gas turbine power plant based on exergy analysis

    International Nuclear Information System (INIS)

    Ibrahim, Thamir K.; Basrawi, Firdaus; Awad, Omar I.; Abdullah, Ahmed N.; Najafi, G.; Mamat, Rizlman; Hagos, F.Y.

    2017-01-01

    Highlights: • Modelling theoretical framework for the energy and exergy analysis of the Gas turbine. • Investigated the effects of ambient temperature on the energy and exergy performance. • The maximum exergy loss occurs in the gas turbine components. - Abstract: This study is about energy and exergy analysis of gas turbine power plant. Energy analysis is more quantitatively while exergy analysis is about the same but with the addition of qualitatively. The lack quality of the thermodynamic process in the system leads to waste of potential energy, also known as exergy destruction which affects the efficiency of the power plant. By using the first and second law of thermodynamics, the model for the gas turbine power plant is built. Each component in the thermal system which is an air compressor, combustion chamber and gas turbine play roles in affecting the efficiency of the gas turbine power plant. The exergy flow rate for the compressor (AC), the combustion chamber (CC) and the gas turbine (GT) inlet and outlet are calculated based on the physical exergy and chemical exergy. The exergy destruction calculation based on the difference between the exergy flow in and exergy flow out of the component. The combustion chamber has the highest exergy destruction. The air compressor has 94.9% and 92% of exergy and energy efficiency respectively. The combustion chamber has 67.5% and 61.8% of exergy and energy efficiency respectively while gas turbine has 92% and 82% of exergy and energy efficiency respectively. For the overall efficiency, the plant has 32.4% and 34.3% exergy and energy efficiency respectively. To enhance the efficiency, the intake air temperature should be reduced, modify the combustion chamber to have the better air-fuel ratio and increase the capability of the gas turbine to receive high inlet temperature.

  3. Stress analysis and life prediction of gas turbine blade

    Science.gov (United States)

    Hsiung, H. C.; Dunn, A. J.; Woodling, D. R.; Loh, D. L.

    1988-01-01

    A stress analysis procedure is presented for a redesign of the Space Shuttle Main Engine high pressure fuel turbopump turbine blades. The analysis consists of the one-dimensional scoping analysis to support the design layout and the follow-on three-dimensional finite element analysis to confirm the blade design at operating loading conditions. Blade life is evaluated based on high-cycle fatigue and low-cycle fatigue.

  4. Frequency Analysis of Failure Scenarios from Shale Gas Development.

    Science.gov (United States)

    Abualfaraj, Noura; Gurian, Patrick L; Olson, Mira S

    2018-04-29

    This study identified and prioritized potential failure scenarios for natural gas drilling operations through an elicitation of people who work in the industry. A list of twelve failure scenarios of concern was developed focusing on specific events that may occur during the shale gas extraction process involving an operational failure or a violation of regulations. Participants prioritized the twelve scenarios based on their potential impact on the health and welfare of the general public, potential impact on worker safety, how well safety guidelines protect against their occurrence, and how frequently they occur. Illegal dumping of flowback water, while rated as the least frequently occurring scenario, was considered the scenario least protected by safety controls and the one of most concern to the general public. In terms of worker safety, the highest concern came from improper or inadequate use of personal protective equipment (PPE). While safety guidelines appear to be highly protective regarding PPE usage, inadequate PPE is the most directly witnessed failure scenario. Spills of flowback water due to equipment failure are of concern both with regards to the welfare of the general public and worker safety as they occur more frequently than any other scenario examined in this study.

  5. Integral Transport Analysis Results for Ions Flowing Through Neutral Gas

    Science.gov (United States)

    Emmert, Gilbert; Santarius, John

    2017-10-01

    Results of a computational model for the flow of energetic ions and neutrals through a background neutral gas will be presented. The method models reactions as creating a new source of ions or neutrals if the energy or charge state of the resulting particle is changed. For a given source boundary condition, the creation and annihilation of the various species is formulated as a 1-D Volterra integral equation that can quickly be solved numerically by finite differences. The present work focuses on multiple-pass, 1-D ion flow through neutral gas and a nearly transparent, concentric anode and cathode pair in spherical, cylindrical, or linear geometry. This has been implemented as a computer code for atomic (3He, 3He +, 3He + +) and molecular (D, D2, D-, D +, D2 +, D3 +) ion and neutral species, and applied to modeling inertial-electrostatic connement (IEC) devices. The code yields detailed energy spectra of the various ions and energetic neutral species. Calculations for several University of Wisconsin IEC and ion implantation devices will be presented. Research supported by US Dept. of Homeland Security Grant 2015-DN-077-ARI095, Dept. of Energy Grant DE-FG02-04ER54745, and the Grainger Foundation.

  6. Trash to Gas (TtG) Simulant Analysis

    Science.gov (United States)

    Miles, John D., II; Hintze, Paul E.

    2014-01-01

    Space exploration in outer earths orbit is a long-term commitment, where the reuse of discarded materials is a critical component for its success. The Logistics Reduction and Repurposing (LRR) project under the NASA Advanced Exploration System Program is a project focused on technologies that reduce the amount of consumables that are needed to be sent into space, repurpose items sent to space, or convert wastes to commodities. In particular, Trash to Gas (TtG), part of the LRR project, is a novel space technology capable of converting raw elements from combustible waste including food waste and packaging, paper, wipes and towels, nitrile gloves, fecal matter, urine brine, maximum absorbency garments, and other organic wastes from human space exploration into useful gases. Trash to gas will ultimately reduce mission cost by producing a portion of important consumables in situ. This paper will discuss results of waste processing by steam reforming. Steam reforming is a thermochemical process developed as part of TtG, where waste is heated in the presence of oxygen and steam to produce carbon dioxide, carbon monoxide, hydrogen, methane and water. The aim of this experiment is to investigate the processing of different waste simulants and their gaseous products. This will lay a foundation for understating and optimizing the production of useful gases for propulsion and recovery of water for life support.

  7. Cycle analysis of MCFC/gas turbine system

    Directory of Open Access Journals (Sweden)

    Musa Abdullatif

    2017-01-01

    Full Text Available High temperature fuel cells such as the solid oxide fuel cell (SOFC and the molten carbonate fuel cell (MCFC are considered extremely suitable for electrical power plant application. The molten carbonate fuel cell (MCFC performances is evaluated using validated model for the internally reformed (IR fuel cell. This model is integrated in Aspen Plus™. Therefore, several MCFC/Gas Turbine systems are introduced and investigated. One of this a new cycle is called a heat recovery (HR cycle. In the HR cycle, a regenerator is used to preheat water by outlet air compressor. So the waste heat of the outlet air compressor and the exhaust gases of turbine are recovered and used to produce steam. This steam is injected in the gas turbine, resulting in a high specific power and a high thermal efficiency. The cycles are simulated in order to evaluate and compare their performances. Moreover, the effects of an important parameters such as the ambient air temperature on the cycle performance are evaluated. The simulation results show that the HR cycle has high efficiency.

  8. Analysis of noble gas recycling at a fusion plasma divertor

    International Nuclear Information System (INIS)

    Brooks, J.N.

    1996-01-01

    Near-surface recycling of neon and argon atoms and ions at a divertor has been studied using impurity transport and surface interaction codes. A fixed background deuterium endash tritium plasma model is used corresponding to the International Thermonuclear Experimental Reactor (ITER) [ITER EDA Agreement and Protocol 2, ITER EDA Documentation Series No. 5 (International Atomic Energy Agency, Vienna, 1994)] radiative plasma conditions (T e ≤10 eV). The noble gas transport depends critically on the divertor surface material. For low-Z materials (Be and C) both neon and argon recycle many (e.g., ∼100) times before leaving the near-surface region. This is also true for an argon on tungsten combination. For neon on tungsten, however, there is low recycling. These variations are due to differences in particle and energy reflection coefficients, mass, and ionization rates. In some cases a high flux of recycling atoms is ionized within the magnetic sheath and this can change local sheath parameters. Due to inhibited backflow, high recycling, and possibly high sputtering, noble gas seeding (for purposes of enhancing radiation) may be incompatible with Be or C surfaces, for fusion reactor conditions. On the other hand, neon use appears compatible with tungsten. copyright 1996 American Institute of Physics

  9. Cycle analysis of MCFC/gas turbine system

    Science.gov (United States)

    Musa, Abdullatif; Alaktiwi, Abdulsalam; Talbi, Mosbah

    2017-11-01

    High temperature fuel cells such as the solid oxide fuel cell (SOFC) and the molten carbonate fuel cell (MCFC) are considered extremely suitable for electrical power plant application. The molten carbonate fuel cell (MCFC) performances is evaluated using validated model for the internally reformed (IR) fuel cell. This model is integrated in Aspen Plus™. Therefore, several MCFC/Gas Turbine systems are introduced and investigated. One of this a new cycle is called a heat recovery (HR) cycle. In the HR cycle, a regenerator is used to preheat water by outlet air compressor. So the waste heat of the outlet air compressor and the exhaust gases of turbine are recovered and used to produce steam. This steam is injected in the gas turbine, resulting in a high specific power and a high thermal efficiency. The cycles are simulated in order to evaluate and compare their performances. Moreover, the effects of an important parameters such as the ambient air temperature on the cycle performance are evaluated. The simulation results show that the HR cycle has high efficiency.

  10. Spacetimes containing slowly evolving horizons

    International Nuclear Information System (INIS)

    Kavanagh, William; Booth, Ivan

    2006-01-01

    Slowly evolving horizons are trapping horizons that are ''almost'' isolated horizons. This paper reviews their definition and discusses several spacetimes containing such structures. These include certain Vaidya and Tolman-Bondi solutions as well as (perturbatively) tidally distorted black holes. Taking into account the mass scales and orders of magnitude that arise in these calculations, we conjecture that slowly evolving horizons are the norm rather than the exception in astrophysical processes that involve stellar-scale black holes

  11. Natural selection promotes antigenic evolvability.

    Science.gov (United States)

    Graves, Christopher J; Ros, Vera I D; Stevenson, Brian; Sniegowski, Paul D; Brisson, Dustin

    2013-01-01

    The hypothesis that evolvability - the capacity to evolve by natural selection - is itself the object of natural selection is highly intriguing but remains controversial due in large part to a paucity of direct experimental evidence. The antigenic variation mechanisms of microbial pathogens provide an experimentally tractable system to test whether natural selection has favored mechanisms that increase evolvability. Many antigenic variation systems consist of paralogous unexpressed 'cassettes' that recombine into an expression site to rapidly alter the expressed protein. Importantly, the magnitude of antigenic change is a function of the genetic diversity among the unexpressed cassettes. Thus, evidence that selection favors among-cassette diversity is direct evidence that natural selection promotes antigenic evolvability. We used the Lyme disease bacterium, Borrelia burgdorferi, as a model to test the prediction that natural selection favors amino acid diversity among unexpressed vls cassettes and thereby promotes evolvability in a primary surface antigen, VlsE. The hypothesis that diversity among vls cassettes is favored by natural selection was supported in each B. burgdorferi strain analyzed using both classical (dN/dS ratios) and Bayesian population genetic analyses of genetic sequence data. This hypothesis was also supported by the conservation of highly mutable tandem-repeat structures across B. burgdorferi strains despite a near complete absence of sequence conservation. Diversification among vls cassettes due to natural selection and mutable repeat structures promotes long-term antigenic evolvability of VlsE. These findings provide a direct demonstration that molecular mechanisms that enhance evolvability of surface antigens are an evolutionary adaptation. The molecular evolutionary processes identified here can serve as a model for the evolution of antigenic evolvability in many pathogens which utilize similar strategies to establish chronic infections.

  12. Natural selection promotes antigenic evolvability.

    Directory of Open Access Journals (Sweden)

    Christopher J Graves

    Full Text Available The hypothesis that evolvability - the capacity to evolve by natural selection - is itself the object of natural selection is highly intriguing but remains controversial due in large part to a paucity of direct experimental evidence. The antigenic variation mechanisms of microbial pathogens provide an experimentally tractable system to test whether natural selection has favored mechanisms that increase evolvability. Many antigenic variation systems consist of paralogous unexpressed 'cassettes' that recombine into an expression site to rapidly alter the expressed protein. Importantly, the magnitude of antigenic change is a function of the genetic diversity among the unexpressed cassettes. Thus, evidence that selection favors among-cassette diversity is direct evidence that natural selection promotes antigenic evolvability. We used the Lyme disease bacterium, Borrelia burgdorferi, as a model to test the prediction that natural selection favors amino acid diversity among unexpressed vls cassettes and thereby promotes evolvability in a primary surface antigen, VlsE. The hypothesis that diversity among vls cassettes is favored by natural selection was supported in each B. burgdorferi strain analyzed using both classical (dN/dS ratios and Bayesian population genetic analyses of genetic sequence data. This hypothesis was also supported by the conservation of highly mutable tandem-repeat structures across B. burgdorferi strains despite a near complete absence of sequence conservation. Diversification among vls cassettes due to natural selection and mutable repeat structures promotes long-term antigenic evolvability of VlsE. These findings provide a direct demonstration that molecular mechanisms that enhance evolvability of surface antigens are an evolutionary adaptation. The molecular evolutionary processes identified here can serve as a model for the evolution of antigenic evolvability in many pathogens which utilize similar strategies to establish

  13. Thermodynamic analysis of turbine blade cooling on the performance of gas turbine cycle

    International Nuclear Information System (INIS)

    Sarabchi, K.; Shokri, M.

    2002-01-01

    Turbine inlet temperature strongly affects gas turbine performance. Today blade cooling technologies facilitate the use of higher inlet temperatures. Of course blade cooling causes some thermodynamic penalties that destroys to some extent the positive effect of higher inlet temperatures. This research aims to model and evaluate the performance of gas turbine cycle with air cooled turbine. In this study internal and transpiration cooling methods has been investigated and the penalties as the result of gas flow friction, cooling air throttling, mixing of cooling air flow with hot gas flow, and irreversible heat transfer have been considered. In addition, it is attempted to consider any factor influencing actual conditions of system in the analysis. It is concluded that penalties due to blade cooling decrease as permissible temperature of the blade surface increases. Also it is observed that transpiration method leads to better performance of gas turbine comparing to internal cooling method

  14. Analysis of senior high school student understanding on gas kinetic theory material

    Science.gov (United States)

    Anri, Y.; Maknun, J.; Chandra, D. T.

    2018-05-01

    The purpose of this research conducted to find out student understanding profile about gas kinetic theory. Particularly, on ideal gas law material, ideal gas equations and kinetic energy of ideal gas. This research was conducted on student of class XII in one of the schools in Bandung. This research is a descriptive research. The data of this research collected by using test instrument which was the essay that has been developed by the researcher based on Bloom’s Taxonomy revised. Based on the analysis result to student answer, this research discovered that whole student has low understanding in the material of gas kinetic theory. This low understanding caused of the misconception of the student, student attitude on physic subjects, and teacher teaching method who are less helpful in obtaining clear pictures in material being taught.

  15. Greenhouse gas emissions in Hawaii. Household and visitor expenditure analysis

    International Nuclear Information System (INIS)

    Konan, Denise Eby; Chan, Hing Ling

    2010-01-01

    This paper focuses on petroleum use and greenhouse gas emissions associated with economic activities in Hawaii. Data on economic activity, petroleum consumption by type (gasoline, diesel, aviation fuel, residual, propane), and emissions factors are compiled and analyzed. In the baseline year 1997, emissions are estimated to total approximately 23.2 million metric tons of carbon, 181 thousand metric tons of nitrous oxide, and 31 thousand metric tons of methane in terms of carbon-equivalent global warming potential over a 100-year horizon. Air transportation, electricity, and other transportation are the key economic activity responsible for GHG emissions associated with fossil fuel use. More than 22% of total emissions are attributed to visitor expenditures. On a per person per annum basis, emission rates generated by visitor demand are estimated to be higher than that of residents by a factor of 4.3 for carbon, 3.2 for methane, and 4.8 for nitrous oxide. (author)

  16. Performance Analysis of Depleted Oil Reservoirs for Underground Gas Storage

    Directory of Open Access Journals (Sweden)

    Dr. C.I.C. Anyadiegwu

    2014-02-01

    Full Text Available The performance of underground gas storage in depleted oil reservoir was analysed with reservoir Y-19, a depleted oil reservoir in Southern region of the Niger Delta. Information on the geologic and production history of the reservoir were obtained from the available field data of the reservoir. The verification of inventory was done to establish the storage capacity of the reservoir. The plot of the well flowing pressure (Pwf against the flow rate (Q, gives the deliverability of the reservoir at various pressures. Results of the estimated properties signified that reservoir Y-19 is a good candidate due to its storage capacity and its flow rate (Q of 287.61 MMscf/d at a flowing pressure of 3900 psig

  17. Reliability analysis of hydrologic containment of liquefied petroleum gas within unlined rock caverns.

    Science.gov (United States)

    Gao, X.; Yan, E. C.; Yeh, T. C. J.; Wang, Y.; Liang, Y.; Hao, Y.

    2017-12-01

    Notice that most of the underground liquefied petroleum gas (LPG) storage caverns are constructed in unlined rock caverns (URCs), where the variability of hydraulic properties (in particular, hydraulic conductivity) has significant impacts on hydrologic containment performance. However, it is practically impossible to characterize the spatial distribution of these properties in detail at the site of URCs. This dilemma forces us to cope with uncertainty in our evaluations of gas containment. As a consequence, the uncertainty-based analysis is deemed more appropriate than the traditional deterministic analysis. The objectives of this paper are 1) to introduce a numerical first order method to calculate the gas containment reliability within a heterogeneous, two-dimensional unlined rock caverns, and 2) to suggest a strategy for improving the gas containment reliability. In order to achieve these goals, we first introduced the stochastic continuum representation of saturated hydraulic conductivity (Ks) of fractured rock and analyzed the spatial variability of Ks at a field site. We then conducted deterministic simulations to demonstrate the importance of heterogeneity of Ks in the analysis of gas tightness performance of URCs. Considering the uncertainty of the heterogeneity in the real world situations, we subsequently developed a numerical first order method (NFOM) to determine the gas tightness reliability at crucial locations of URCs. Using the NFOM, the effect of spatial variability of Ks on gas tightness reliability was investigated. Results show that as variance or spatial structure anisotropy of Ks increases, most of the gas tightness reliability at crucial locations reduces. Meanwhile, we compare the results of NFOM with those of Monte Carlo simulation, and we find the accuracy of NFOM is mainly affected by the magnitude of the variance of Ks. At last, for improving gas containment reliability at crucial locations at this study site, we suggest that vertical

  18. Dynamic Modeling and Analysis of an Industrial Gas Suspension Absorber for Flue Gas Desulfurization

    DEFF Research Database (Denmark)

    Cignitti, Stefano; Mansouri, Seyed Soheil; Sales-Cruz, Mauricio

    2016-01-01

    parameters were fitted to operational data from a real cement plant. A detailed statistical analysis of the parameter estimation procedure was performed, and the confidence intervals for estimated kinetic parameters were calculated. The model and reaction rate expression prediction ability was tested using...... another plant data set. It was verified that in spite of the simplicity of the model, very good prediction of industrial behavior was obtained. Furthermore, the dynamic analysis of the system was performed by carrying out open-loop and closed-loop simulations to verify plant dynamics. Therefore, a simple...... dynamic model with a reaction rate expression that is simple and efficient to use to predict the dynamics of GSA process was proposed in this work....

  19. A Driving Force Analysis and Forecast for Gas Consumption Demand in China

    Directory of Open Access Journals (Sweden)

    Qing Zhu

    2014-01-01

    Full Text Available In recent years, gas has begun to be widely used in power generation as well as in manufacturing because of the environmental advantages, lower cost, and the relative safety and reliability. Accurate prediction of future gas consumption is of great importance for energy security. In this paper, we first use path analysis to select the core factors that impact gas consumption, then use the RBF-QRNN model and BVAR model separately to predict future gas consumption, and finally discuss and compare the results from the two models. The results show that if there is a positive growth in GDP, urbanization, and population, then gas consumption is expected to increase over a comparatively long time. In detail, gas consumption is expected to remain at about 25% of all energy consumption, GDP’s contribution to gas consumption is expected to be about 53%, and the urbanization rate contribution would be about 15%. Gas consumption in China is predicted to reach around 178649.23 million cubic meters by the end of 2015 and about 264698.86 million cubic meters by 2020.

  20. Rotordynamic analysis for stepped-labyrinth gas seals using moody's friction-factor model

    International Nuclear Information System (INIS)

    Ha, Tae Woong

    2001-01-01

    The governing equations are derived for the analysis of a stepped labyrinth gas seal generally used in high performance compressors, gas turbines, and steam turbines. The bulk-flow is assumed for a single cavity control volume set up in a stepped labyrinth cavity and the flow is assumed to be completely turbulent in the circumferential direction. The Moody's wall-friction-factor model is used for the calculation of wall shear stresses in the single cavity control volume. For the reaction force developed by the stepped labyrinth gas seal, linearized zeroth-order and first-order perturbation equations are developed for small motion about a centered position. Integration of the resultant first-order pressure distribution along and around the seal defines the rotordynamic coefficients of the stepped labyrinth gas seal. The resulting leakage and rotordynamic characteristics of the stepped labyrinth gas seal are presented and compared with Scharrer's theoretical analysis using Blasius' wall-friction-factor model. The present analysis shows a good qualitative agreement of leakage characteristics with Scharrer's analysis, but underpredicts by about 20 %. For the rotordynamic coefficients, the present analysis generally yields smaller predicted values compared with Scharrer's analysis

  1. Uncertainty and sensitivity analysis of fission gas behavior in engineering-scale fuel modeling

    Energy Technology Data Exchange (ETDEWEB)

    Pastore, Giovanni, E-mail: Giovanni.Pastore@inl.gov [Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Swiler, L.P., E-mail: LPSwile@sandia.gov [Optimization and Uncertainty Quantification, Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185-1318 (United States); Hales, J.D., E-mail: Jason.Hales@inl.gov [Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Novascone, S.R., E-mail: Stephen.Novascone@inl.gov [Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Perez, D.M., E-mail: Danielle.Perez@inl.gov [Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Spencer, B.W., E-mail: Benjamin.Spencer@inl.gov [Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Luzzi, L., E-mail: Lelio.Luzzi@polimi.it [Politecnico di Milano, Department of Energy, Nuclear Engineering Division, via La Masa 34, I-20156 Milano (Italy); Van Uffelen, P., E-mail: Paul.Van-Uffelen@ec.europa.eu [European Commission, Joint Research Centre, Institute for Transuranium Elements, Hermann-von-Helmholtz-Platz 1, D-76344 Karlsruhe (Germany); Williamson, R.L., E-mail: Richard.Williamson@inl.gov [Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States)

    2015-01-15

    The role of uncertainties in fission gas behavior calculations as part of engineering-scale nuclear fuel modeling is investigated using the BISON fuel performance code with a recently implemented physics-based model for fission gas release and swelling. Through the integration of BISON with the DAKOTA software, a sensitivity analysis of the results to selected model parameters is carried out based on UO{sub 2} single-pellet simulations covering different power regimes. The parameters are varied within ranges representative of the relative uncertainties and consistent with the information in the open literature. The study leads to an initial quantitative assessment of the uncertainty in fission gas behavior predictions with the parameter characterization presently available. Also, the relative importance of the single parameters is evaluated. Moreover, a sensitivity analysis is carried out based on simulations of a fuel rod irradiation experiment, pointing out a significant impact of the considered uncertainties on the calculated fission gas release and cladding diametral strain. The results of the study indicate that the commonly accepted deviation between calculated and measured fission gas release by a factor of 2 approximately corresponds to the inherent modeling uncertainty at high fission gas release. Nevertheless, significantly higher deviations may be expected for values around 10% and lower. Implications are discussed in terms of directions of research for the improved modeling of fission gas behavior for engineering purposes.

  2. Leakage analysis of fuel gas pipe in large LNG carrier engine room

    Directory of Open Access Journals (Sweden)

    CEN Zhuolun

    2017-10-01

    Full Text Available [Objectives] The electric propulsion dual-fuel engine is becoming dominant in newly built Liquefied Natural Gas(LNGcarriers. To avoid the potential risks that accompany the use of flammable and explosive boil-off gas,the performance of precise safety and reliability assessments is indispensable. [Methods] This research concerns the engine rooms of large LNG carriers which are propelled electrically by a dual-fuel engine. Possible fuel gas(natural gasleak cases in different areas of the engine room are simulated and analyzed. Five representative leak cases defined by leak form,leak location and leak rate are entered into a Computational Fluid Dynamics(CFDsimulation,in which the Reynolds stress model of Fluent software is adopted as the turbulence model. The results of the leaked gas distribution and ventilation velocity field are analyzed in combination to obtain the diffusion tendency and concentration distribution of leaked gas in different areas.[Results] Based on an analysis of the results,an optimized arrangement of flammable gas detectors is provided for the engine room, and the adoption of an explosion-proof exhaust fan is proven to be unnecessary.[Conclusions] These analysis methods can provide a reference for similar gas leakage scenarios occurring in confined ventilated spaces. In addition, the simulation results can be used to quantitatively assess potential fire or explosion damage in order to guide the design of structural reinforcements.

  3. Adapting Human Reliability Analysis from Nuclear Power to Oil and Gas Applications

    Energy Technology Data Exchange (ETDEWEB)

    Boring, Ronald Laurids [Idaho National Laboratory

    2015-09-01

    ABSTRACT: Human reliability analysis (HRA), as currently used in risk assessments, largely derives its methods and guidance from application in the nuclear energy domain. While there are many similarities be-tween nuclear energy and other safety critical domains such as oil and gas, there remain clear differences. This paper provides an overview of HRA state of the practice in nuclear energy and then describes areas where refinements to the methods may be necessary to capture the operational context of oil and gas. Many key distinctions important to nuclear energy HRA such as Level 1 vs. Level 2 analysis may prove insignifi-cant for oil and gas applications. On the other hand, existing HRA methods may not be sensitive enough to factors like the extensive use of digital controls in oil and gas. This paper provides an overview of these con-siderations to assist in the adaptation of existing nuclear-centered HRA methods to the petroleum sector.

  4. Shale Gas in Poland: an Analysis of Tax Mechanisms and Dynamic Interactions

    Directory of Open Access Journals (Sweden)

    Dawid Walentek

    2016-12-01

    Full Text Available This is a preliminary research into possible taxation mechanisms for firms that will be operating in the shale gas industry in Poland and potential market interactions between the incumbents and the entrants. The study places focus on the level of welfare and it includes a static and a dynamic analysis. The result of the former is that the lump sum tax is the first best of all considered tax mechanisms for the Polish shale gas from the welfare perspective. The second best option for taxation is a combination of the current CIT rate and a windfall profit tax. In respect to the dynamic analysis, the results suggest that Gazprom can remain the market leader in Poland even if the shale gas producers start to operate, due to the sequential character of the competition in the Polish natural gas market. Counterintuitively, it will not come at the expenses of the consumers in Poland and it can bring potential welfare gains

  5. Development of conjugate methods with gas chromatography for inorganic compounds analysis

    International Nuclear Information System (INIS)

    Baccan, N.

    1975-01-01

    The application of gas chromatography combined with mass spectrometry or with nuclear methods for the analysis of inorganic compounds is studied. The advantages of the use of a gas chromatograph coupled with a quadrupole mass spectrometer or with a high resolution radiation detector, are discussed. We also studied the formation and solvent extraction of metal chelates; an aliquot of the organic phase was directly injected into the gas chromatograph and the eluted compounds were detected by mass spectrometry or, when radioactive, by nuclear methods. (author)

  6. Techno-economic analysis and optimization of the heat recovery of utility boiler flue gas

    International Nuclear Information System (INIS)

    Xu, Gang; Huang, Shengwei; Yang, Yongping; Wu, Ying; Zhang, Kai; Xu, Cheng

    2013-01-01

    Highlights: • Four typical flue gas heat recovery schemes are quantitatively analyzed. • The analysis considers thermodynamic, heat transfer and hydrodynamics factors. • Techno-economic analysis and optimization design are carried out. • High-stage steam substitute scheme obtains better energy-saving effect. • Large heat transfer area and high flue gas resistances weaken overall performance. - Abstract: Coal-fired power plants in China consume nearly half of available coals, and the resulting CO 2 emissions cover over 40% of total national emissions. Therefore, reducing the energy expenditure of coal-fired power plants is of great significance to China’s energy security and greenhouse gas reduction programs. For coal-fired power plants, the temperature of a boiler’s exhaust gas reaches 120–150 °C or even higher. The thermal energy of boiler’s exhaust accounts for approximately 3–8% of the total energy of fuel input. Given these factors, we conducted a techno-economic analysis and optimization design of the heat recovery system using boiler exhaust gas. This research is conformed to the principles of thermodynamic, heat transfer, and hydrodynamics. Based on the data from an existing 1000 MW typical power generation unit in China, four typical flue gas heat recovery schemes are quantitatively analyzed from the thermodynamics perspective. The impacts of flue gas heat recovery on net work output and standard coal consumption rate of various schemes are performed. Furthermore, the transfer area of heat recovery exchanger and the draft fan work increment due to the flue gas pressure drop are analyzed. Finally, a techno-economic analysis of the heat recovery schemes is conducted, and some recommendations on optimization design parameters are proposed, with full consideration of various factors such as the decrease on fuel cost due to energy conservation as well as the investment cost of heat recovery retrofitting. The results revealed that, high

  7. Heat transfer analysis of unsteady graphene oxide nanofluid flow using a fuzzy identifier evolved by genetically encoded mutable smart bee algorithm

    Directory of Open Access Journals (Sweden)

    Mohammadreza Azimi

    2015-03-01

    Full Text Available In the current research, the unsteady two dimensional Graphene Oxide water based nanofluid heat transfer between two moving parallel plates is analyzed using an intelligent black-box identifier. The developed intelligent tool is known as evolvable evolutionary fuzzy inference system (EE-FIS which is based on the integration of low-level fuzzy programming and hyper-level evolutionary computing concepts. Here, the authors propose the use of a modified evolutionary algorithm (EA which is called hybrid genetic mutable smart bee algorithm (HGMSBA. The proposed HGMSBA is used to evolve both antecedent and consequent parts of fuzzy rule base. Besides, it tries to prune the rule base of fuzzy inference system (FIS to decrease its computational complexity and increase its interpretability. By considering the prediction error of the fuzzy identifier as the objective function of HGMSBA, an automatic soft interpolation machine is developed which can intuitively increase the robustness and accuracy of the final model. Here, HGMSBA-FIS is used to provide a nonlinear map between inputs, i.e. nanoparticles solid volume fraction (ϕ, Eckert number (Ec and a moving parameter which describes the movements of plates (S, and output, i.e. Nusselt number (Nu. Prior to proceeding with the modeling process, a comprehensive numerical comparative study is performed to investigate the potentials of the proposed model for nonlinear system identification. After demonstrating the efficacy of HGMSBA for training the FIS, the system is applied to the considered problem. Based on the obtained results, it can be inferred that the developed HGMSBA-FIS black-box identifier can be used as a very authentic tool with respect to accuracy and robustness. Besides, as the proposed black-box is not a physics-based identifier, it frees experts from the cumbersome mathematical formulations, and can be used for advanced real-time applications such as model-based control. The simulations

  8. Application of Pyrolysis - Gas Chromatography/Mass Spectrometry in Failure Analysis in the Automotive Industry

    OpenAIRE

    Kusch, Peter (Dr.)

    2015-01-01

    This book chapter describes application examples of gas chromatography/mass spectrometry and pyrolysis – gas chromatography/mass spectrometry in failure analysis for the identification of chemical materials like mineral oils and nitrile rubber gaskets. Furthermore, failure cases demanding identification of polymers/copolymers in fouling on the compressor wall of a car air conditioner and identification of fouling on the surface of a bearing race from the automotive industry are demonstr...

  9. SIMULATION AND PRELIMINARY ECONOMIC ANALYSIS OF A COMPLEX OF NUTRIENTS USING CAMISEA GAS

    OpenAIRE

    Porlles L., J.; Cárdenas R., J.

    2014-01-01

    Peru is in fact a country with important reservoirs of natural gas as Camisea and it opens potential opportunities for gas chemical development. In a mark of a higher enterprise competitiveness, in industry any time is more generalized to account with tools as support for enhanced of process and cost savings. The simulation and optimization of industrial process aided by computer is a powerful alternative. This work has as propose to make the design of a process an economical analysis with pr...

  10. Analysis of GRI North American Regional Gas Supply-Demand Model

    International Nuclear Information System (INIS)

    Nesbitt, D.M.; Singh, J.; Pine, G.D.; Kline, D.; Barron, M.; Cheung, P.D.

    1989-01-01

    This paper summarizes the results from the GRI North American Regional Gas Supply-Demand Model using the four scenarios defined for the Energy Modeling Forum Number 9 (EMF-9) described in EMF-9 Working Paper 9.4 (1987). The analysis is designed both to showcase the GRI North American Regional model as well as to infer meaningful results about the North American natural gas system. The focus of the analysis is not R ampersand D per se; R ampersand D analysis using the model is conducted regularly by GRI and described elsewhere. Rather, the objective is to analyze some of the major uncertainties in the North American gas market, uncertainties that potentially affect all players including GRI. In particular, the authors seek to quantify the overall economic environment in which production, transmission, distribution, consumption, and R ampersand D decisions will be made and how different that overall environment might be under alternative assumptions. An attendant objective of this analysis has been to enlist economists from a range of organizations (producers, regulators, GRI, and consultants) to carefully scrutinize the GRI North American Regional model and results. In particular, the coauthors were assembled from diverse organizations to review and evaluate model outputs, applying their particular experience and perspective. The four EMF-9 scenarios upon which this paper is based are described in detail later in this document. Briefly, scenario one represents a world with a surfeit of gas and a relatively high oil price projection; scenario two considers a lower oil price forecast; scenario three assumes a pessimistic outlook for the gas resource base with the same oil prices as scenario one; and scenario four examines a higher level of demand for gas in the North American gas market. An important objective of this analysis is to illustrate the predictive power of multi-scenario comparisons (as contrasted with detailed analysis of any individual scenario)

  11. Hermetic conditions for the gas-in-oil analysis. Testing of transformer oil; Hermetische Bedingungen fuer die Gas-in-Oel-Analyse. Pruefung von Transformatorenoel

    Energy Technology Data Exchange (ETDEWEB)

    Braesel, Eckhard; Braesel, Olaf [Gatron GmbH, Greifswald (Germany); Sasum, Ute [Forschungszentrum Sensorik Greifswald e.V., Greifswald (Germany)

    2012-06-25

    The protection of hermetic conditions for the gas-in-oil analysis is performed as an innovative method of sampling with integrated gas extraction. It also is controllable with a criterion derived from online monitoring. The importance is in the utilization of all individual gases in the diagnosis and in the determination of the accuracy of DGA results as well as the laboratory control.

  12. The encounter and analysis of naturally occurring radionuclides in gas and oil production and processing

    International Nuclear Information System (INIS)

    Hartog, F.A.; Jonkers, G.; Knaepen, W.A.I.

    1996-01-01

    As a result of oil and gas production, radioactive daughter elements from the uranium and thorium decay series can be mobilized and transported away from the reservoir. Due to changes in flow regime, temperature, pressure or chemical environment NORs (Naturally Occurring Radionuclides) may build up in products, by-products or waste streams from gas and oil production and processing facilities. Products containing NORs are commonly denoted by the acronym NORM (Naturally Occurring Radioactive Materials). Main topics of this paper are: E and P (Exploration and Production) NORM characteristics; incentives for NORM analysis; NORM analysis; interlaboratory test programme; analysis techniques; results and conclusions of the test programme. 4 figs., 2 tabs

  13. A model-based analysis of the implications of shale gas developments for the European gas market

    Energy Technology Data Exchange (ETDEWEB)

    De Joode, J.; Plomp, A.J.; Ozdemir, O. [ECN Policy Studies, Petten (Netherlands)

    2012-04-15

    Shale gas in Europe could potentially be a big thing, especially in particular regions. Whereas test drillings need to confirm the technical recoverability of deposits and further research is needed on the environmental and safety aspects of shale gas production, this paper illustrates that shale gas developments may have substantial implications for regional gas balances, gas flows, and infrastructure requirements throughout Europe in the next decades.

  14. Advanced exergetic analysis of five natural gas liquefaction processes

    International Nuclear Information System (INIS)

    Vatani, Ali; Mehrpooya, Mehdi; Palizdar, Ali

    2014-01-01

    Highlights: • Advanced exergetic analysis was investigated for five LNG processes. • Avoidable/unavoidable and endogenous/exogenous irreversibilities were calculated. • Advanced exergetic analysis identifies the potentials for improving the system. - Abstract: Conventional exergy analysis cannot identify portion of inefficiencies which can be avoided. Also this analysis does not have ability to calculate a portion of exergy destruction which has been produced through performance of a component alone. In this study advanced exergetic analysis was performed for five mixed refrigerant LNG processes and four parts of irreversibility (avoidable/unavoidable) and (endogenous/exogenous) were calculated for the components with high inefficiencies. The results showed that portion of endogenous exergy destruction in the components is higher than the exogenous one. In fact interactions among the components do not affect the inefficiencies significantly. Also this analysis showed that structural optimization cannot be useful to decrease the overall process irreversibilities. In compressors high portion of the exergy destruction is related to the avoidable one, thus they have high potential to improve. But in multi stream heat exchangers and air coolers, unavoidable inefficiencies were higher than the other parts. Advanced exergetic analysis can identify the potentials and strategies to improve thermodynamic performance of energy intensive processes

  15. Exergy analysis of a gas turbine power plant | Oko | Journal of ...

    African Journals Online (AJOL)

    Exergy analysis of a 100MW gas turbine power plant that works on the. Brayton cycle is presented. The average increase in the thermodynamic degradation of the plant over the period of six (6) years at three different levels of load was assessed. The exergy analysis of the plant was done on two sets of data: one from the ...

  16. Pixel-based analysis of comprehensive two-dimensional gas chromatograms (color plots) of petroleum

    DEFF Research Database (Denmark)

    Furbo, Søren; Hansen, Asger B.; Skov, Thomas

    2014-01-01

    We demonstrate how to process comprehensive two-dimensional gas chromatograms (GC × GC chromatograms) to remove nonsample information (artifacts), including background and retention time shifts. We also demonstrate how this, combined with further reduction of the influence of irrelevant informati......, allows for data analysis without integration or peak deconvolution (pixelbased analysis)....

  17. Socioeconomic effects of the DOE Gas Centrifuge Enrichment Plant. Volume 1: methodology and analysis

    International Nuclear Information System (INIS)

    1979-01-01

    The socioeconomic effects of the Gas Centrifuge Enrichment Plant being built in Portsmouth, Ohio were studied. Chapters are devoted to labor force, housing, population changes, economic impact, method for analysis of services, analysis of service impacts, schools, and local government finance

  18. Fractal analysis of the dark matter and gas distributions in the Mare-Nostrum universe

    International Nuclear Information System (INIS)

    Gaite, José

    2010-01-01

    We develop a method of multifractal analysis of N-body cosmological simulations that improves on the customary counts-in-cells method by taking special care of the effects of discreteness and large scale homogeneity. The analysis of the Mare-Nostrum simulation with our method provides strong evidence of self-similar multifractal distributions of dark matter and gas, with a halo mass function that is of Press-Schechter type but has a power-law exponent -2, as corresponds to a multifractal. Furthermore, our analysis shows that the dark matter and gas distributions are indistinguishable as multifractals. To determine if there is any gas biasing, we calculate the cross-correlation coefficient, with negative but inconclusive results. Hence, we develop an effective Bayesian analysis connected with information theory, which clearly demonstrates that the gas is biased in a long range of scales, up to the scale of homogeneity. However, entropic measures related to the Bayesian analysis show that this gas bias is small (in a precise sense) and is such that the fractal singularities of both distributions coincide and are identical. We conclude that this common multifractal cosmic web structure is determined by the dynamics and is independent of the initial conditions

  19. The economics of natural gas infrastructure investments. Theory and model-based analysis for Europe

    Energy Technology Data Exchange (ETDEWEB)

    Lochner, Stefan

    2012-07-01

    Changing supply structures, security of supply threats and efforts to eliminate bottlenecks and increase competition in the European gas market potentially warrant infrastructure investments. However, which investments are actually efficient is unclear. From a theoretical perspective, concepts from other sectors regarding the estimation of congestion cost and efficient investment can be applied - with some extensions - to natural gas markets. Investigations in a simple analytical framework, thereby, show that congestion does not necessarily imply that investment is efficient, and that there are multiple interdependencies between investments in different infrastructure elements (pipeline grid, gas storage, import terminals for liquefied natural gas (LNG)) which need to be considered in an applied analysis. Such interdependencies strengthen the case for a model-based analysis. An optimization model minimizing costs can illustrate the first-best solution with respect to investments in natural gas infrastructure; gas market characteristics such as temperature-dependent stochasticity of demand or the lumpiness of investments can be included. Scenario analyses help to show the effects of changing the underlying model presumption. Hence, results are projections subject to data and model assumption - and not forecasts. However, as they depict the optimal, cost-minimizing outcome, results provide a guideline to policymakers and regulators regarding the desirable market outcome. A stochastic mixed-integer dispatch and investment model for the European natural gas infrastructure is developed as an optimization model taking the theoretical inter-dependencies into account. It is based on an extensive infrastructure database including long-distance transmission pipelines, LNG terminals and gas storage sites with a high level of spatial granularity. It is parameterized with assumptions on supply and demand developments as well as empirically derived infrastructure extension costs

  20. Analysis of basis at Eastern hubs and the impact of gas from Sable Island

    International Nuclear Information System (INIS)

    Mortensen, P.; Schlesinger, B.; Ratra, A.

    2000-01-01

    The major changes that are happening in natural gas markets in the northeast region of North America can be attributed to the introduction of Sable Island as a new source of gas supply, new domestic industrial markets for gas in Atlantic Canada and Northern New England, and major growth in gas-fired electric power generation. This report presented a long term outlook for new Canadian gas supplies to the northeastern North American market with particular reference to prices and basis relationships that will develop between major existing and potential market centres in the area. The development of pipeline transmission and merchant power plant construction in the region was also reviewed. Four potential scenarios were examined for the period to 2010 via a model-based approach. Emerging basis trends under various market conditions were projected. The key observations from the analysis are that the basis between Northeast city gates and the major producing areas will probably increase greatly by 2010. The rise in basis is mostly due to growth in gas demand while changes in gas supply will have only a minor impact on basis. It was also suggested that reference levels of gas production from Sable Island will not alter prices in a significant manner, but higher levels of gas production from Sable Island will benefit Sable producers and Northeast consumers. Basis impacts are moderated when enough pipeline capacity exists to enable toll discounting. The report also stated that there is little risk to the basis impact when gas demand is greater than forecasted. Fluctuations will occur around the general basis trend. 18 refs., 26 tabs., 39 figs

  1. Molecular analysis of manufactured gas plant soils for naphthalene mineralization

    International Nuclear Information System (INIS)

    Sanseverino, J.; Werner, C.; Fleming, J.; Applegate, B.M.; King, J.M.H.; Sayler, G.S.; Blackburn, J.

    1991-01-01

    New molecular tools are being developed and tested to ascertain the biodegradability of hazardous wastes by soil bacterial population. The potential for manufactured gas plant (MGP) soil bacterial populations to degrade naphthalene, as a component mixture of polynuclear aromatic hydrocarbons, was evaluated by the detection of a naphthalene biodegradative genotype by DNA probe hybridization with DNA extracts and colonies of cultured bacteria of the MGP soils. The activity of the naphthalene-degrading populations was evaluated by mineralization assays, 14 CO 2 production from 14 C-naphthalene. Direct messenger RNA (mRNA) extraction from MGP soil was evaluated as an instantaneous measure of naphthalene catabolic gene expression in MGP soil. The bioavailability of naphthalene for bacterial degradation within the MGP soils was assessed by measuring the bioluminescent response of a naphthalene-lux catabolic reporter strain Pseudomonas fluorescens HK44 (pUTK21). DNA extracted from 5 MGP soils and 1 creosote-contaminated soil and hybridized with a nahA gene probe indicated that the naphthalene degradative genes were present in all samples in the range of 0.06 to 0.95 ng/100 μl DNA extract which was calculated to represent 3.58 x 10 8 to 1.05 x 10 10 nahA positive cells/g soil. Phenanthrene, anthracene, and benzo(a)pyrene were mineralized also by some of the soils. NAH7 homologous messenger RNA transcripts were detectable in one MGP soil and in the creosote-contaminated soil

  2. Unsteady Probabilistic Analysis of a Gas Turbine System

    Science.gov (United States)

    Brown, Marilyn

    2003-01-01

    In this work, we have considered an annular cascade configuration subjected to unsteady inflow conditions. The unsteady response calculation has been implemented into the time marching CFD code, MSUTURBO. The computed steady state results for the pressure distribution demonstrated good agreement with experimental data. We have computed results for the amplitudes of the unsteady pressure over the blade surfaces. With the increase in gas turbine engine structural complexity and performance over the past 50 years, structural engineers have created an array of safety nets to ensure against component failures in turbine engines. In order to reduce what is now considered to be excessive conservatism and yet maintain the same adequate margins of safety, there is a pressing need to explore methods of incorporating probabilistic design procedures into engine development. Probabilistic methods combine and prioritize the statistical distributions of each design variable, generate an interactive distribution and offer the designer a quantified relationship between robustness, endurance and performance. The designer can therefore iterate between weight reduction, life increase, engine size reduction, speed increase etc.

  3. Multi-scale structural analysis of gas diffusion layers

    Science.gov (United States)

    Göbel, Martin; Godehardt, Michael; Schladitz, Katja

    2017-07-01

    The macroscopic properties of materials are strongly determined by their micro structure. Here, transport properties of gas diffusion layers (GDL) for fuel cells are considered. In order to simulate flow and thermal properties, detailed micro structural information is essential. 3D images obtained by high-resolution computed tomography using synchrotron radiation and scanning electron microscopy (SEM) combined with focused ion beam (FIB) serial slicing were used. A recent method for reconstruction of porous structures from FIB-SEM images and sophisticated morphological image transformations were applied to segment the solid structural components. The essential algorithmic steps for segmenting the different components in the tomographic data-sets are described and discussed. In this paper, two types of GDL, based on a non-woven substrate layer and a paper substrate layer were considered, respectively. More than three components are separated within the synchrotron radiation computed tomography data. That is, fiber system, polytetrafluoroethylene (PTFE) binder/impregnation, micro porous layer (MPL), inclusions within the latter, and pore space are segmented. The usage of the thus derived 3D structure data in different simulation applications can be demonstrated. Simulations of macroscopic properties such as thermal conductivity, depending on the flooding state of the GDL are possible.

  4. Gas-core reactor power transient analysis. Final report

    International Nuclear Information System (INIS)

    Kascak, A.F.

    1972-01-01

    The gas core reactor is a proposed device which features high temperatures. It has applications in high specific impulse space missions, and possibly in low thermal pollution MHD power plants. The nuclear fuel is a ball of uranium plasma radiating thermal photons as opposed to gamma rays. This thermal energy is picked up before it reaches the solid cavity liner by an inflowing seeded propellant stream and convected out through a rocket nozzle. A wall-burnout condition will exist if there is not enough flow of propellant to convect the energy back into the cavity. A reactor must therefore operate with a certain amount of excess propellant flow. Due to the thermal inertia of the flowing propellant, the reactor can undergo power transients in excess of the steady-state wall burnout power for short periods of time. The objective of the study was to determine how long the wall burnout power could be exceeded without burning out the cavity liner. The model used in the heat-transfer calculation was one-dimensional, and thermal radiation was assumed to be a diffusion process. (auth)

  5. Methodology for Structural Integrity Analysis of Gas Turbine Blades

    Directory of Open Access Journals (Sweden)

    Tiago de Oliveira Vale

    2012-03-01

    Full Text Available One of the major sources of stress arising in turbomachinery blades are the centrifugal loads acting at any section of the airfoil. Accounting for this phenomenon stress evaluation of the blade attachment region in the disc has to be performed in order to avoid blade failure. Turbomachinery blades are generally twisted, and the cross section area varies from the root of the blade to the tip. The blade root shape at the attachment region is of great concern. Stress concentrations are predictable at this contact region. In this paper, a finite element model has been created for the purpose of assessing stress at the joint region connecting the blade to the disc slot. Particular attention was paid to the geometric modeling of the "fir-tree" fixing, which is now used in the majority of gas turbine engines. This study has been performed using the commercial software ANSYS 13.0. The disc and blade assembly are forced to move with a certain rotational velocity. Contact connections are predicted on the common faces of the blade and on the disc at the root. Solutions can be obtained to allow the evaluation of stresses. Results can be compared with the mechanical properties of the adopted material.

  6. Calibration strategy for semi-quantitative direct gas analysis using inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Gerdes, Kirk; Carter, Kimberly E.

    2011-01-01

    A process is described by which an ICP-MS equipped with an Octopole Reaction System (ORS) is calibrated using liquid phase standards to facilitate direct analysis of gas phase samples. The instrument response to liquid phase standards is analyzed to produce empirical factors relating ion generation and transmission efficiencies to standard operating parameters. Empirical factors generated for liquid phase samples are then used to produce semi-quantitative analysis of both mixed liquid/gas samples and pure gas samples. The method developed is similar to the semi-quantitative analysis algorithms in the commercial software, which have here been expanded to include gas phase elements such as Xe and Kr. Equations for prediction of relative ionization efficiencies and isotopic transmission are developed for several combinations of plasma operating conditions, which allows adjustment of limited parameters between liquid and gas injection modes. In particular, the plasma temperature and electron density are calculated from comparison of experimental results to the predictions of the Saha equation. Comparisons between operating configurations are made to determine the robustness of the analysis to plasma conditions and instrument operating parameters. Using the methods described in this research, the elemental concentrations in a liquid standard containing 45 analytes and treated as an unknown sample were quantified accurately to ± 50% for most elements using 133 Cs as a single internal reference. The method is used to predict liquid phase mercury within 12% of the actual concentration and gas phase mercury within 28% of the actual concentration. The results verify that the calibration method facilitates accurate semi-quantitative, gas phase analysis of metal species with sufficient sensitivity to quantify metal concentrations lower than 1 ppb for many metallic analytes.

  7. A neighbourhood evolving network model

    International Nuclear Information System (INIS)

    Cao, Y.J.; Wang, G.Z.; Jiang, Q.Y.; Han, Z.X.

    2006-01-01

    Many social, technological, biological and economical systems are best described by evolved network models. In this short Letter, we propose and study a new evolving network model. The model is based on the new concept of neighbourhood connectivity, which exists in many physical complex networks. The statistical properties and dynamics of the proposed model is analytically studied and compared with those of Barabasi-Albert scale-free model. Numerical simulations indicate that this network model yields a transition between power-law and exponential scaling, while the Barabasi-Albert scale-free model is only one of its special (limiting) cases. Particularly, this model can be used to enhance the evolving mechanism of complex networks in the real world, such as some social networks development

  8. Modeling and performance analysis of CCHP (combined cooling, heating and power) system based on co-firing of natural gas and biomass gasification gas

    International Nuclear Information System (INIS)

    Wang, Jiangjiang; Mao, Tianzhi; Sui, Jun; Jin, Hongguang

    2015-01-01

    Co-firing biomass and fossil energy is a cost-effective and reliable way to use renewable energy and offer advantages in flexibility, conversion efficiency and commercial possibility. This study proposes a co-fired CCHP (combined cooling, heating and power) system based on natural gas and biomass gasification gas that contains a down-draft gasifier, ICE (internal combustion engine), absorption chiller and heat exchangers. Thermodynamic models are constructed based on a modifying gasification thermochemical equilibrium model and co-fired ICE model for electricity and heat recovery. The performance analysis for the volumetric mixture ratio of natural gas and product gas indicates that the energy and exergy efficiencies are improved by 9.5% and 13.7%, respectively, for an increasing mixture ratio of 0–1.0. Furthermore, the costs of multi-products, including electricity, chilled water and hot water, based on exergoeconomic analysis are analyzed and discussed based on the influences of the mixture ratio of the two gas fuels, investment cost and biomass cost. - Highlights: • Propose a co-fired CCHP system by natural gas and biomass gasification gas. • Modify biomass gasification and co-fired ICE models. • Present the thermodynamic analysis of the volumetric mixture ratios of two gas fuels. • Energy and exergy efficiencies are improved 9.5% and 13.7%. • Discuss multi-products’ costs influenced by investment and fuel costs.

  9. Analysis of Neutron Flux Distribution in Rsg-Gas Reactor With U-Mo Fuels

    Directory of Open Access Journals (Sweden)

    Taswanda Taryo

    2004-01-01

    Full Text Available The use of U-Mo fuels in research reactors seems to be promising and, recently, world researchers have carried out these such activities actively. The National Nuclear Energy Agency (BATAN which owns RSG-GAS reactor available in Serpong Research Center for Atomic Energy should anticipate this trend. It is, therefore, this research work on the use of U-Mo fuels in RSG-GAS reactor should be carried out. The work was focused on the analysis of neutron flux distribution in the RSG-GAS reactor using different content of molybdenum in U-Mo fuels. To begin with, RSG-GAS reactor core model was developed and simulated into X, Y and Z dimensions. Cross section of materials based on the developed cells of standard and control fuels was then generated using WIMS-D5-B. The criticality calculations were finally carried out applying BATAN-2DIFF code. The results showed that the neutron flux distribution obtained in U-Mo-fuel-based RSG-GAS core is very similar to those achieved in the 300-gram sillicide-fuel-based RSG-GAS reactor core. Indeed, the utilization of the U-Mo RSG-GAS core can be very similar to that of the high-density sillicide reactor core and even could be better in the future.

  10. Visibility graph network analysis of natural gas price: The case of North American market

    Science.gov (United States)

    Sun, Mei; Wang, Yaqi; Gao, Cuixia

    2016-11-01

    Fluctuations in prices of natural gas significantly affect global economy. Therefore, the research on the characteristics of natural gas price fluctuations, turning points and its influencing cycle on the subsequent price series is of great significance. Global natural gas trade concentrates on three regional markets: the North American market, the European market and the Asia-Pacific market, with North America having the most developed natural gas financial market. In addition, perfect legal supervision and coordinated regulations make the North American market more open and more competitive. This paper focuses on the North American natural gas market specifically. The Henry Hub natural gas spot price time series is converted to a visibility graph network which provides a new direction for macro analysis of time series, and several indicators are investigated: degree and degree distribution, the average shortest path length and community structure. The internal mechanisms underlying price fluctuations are explored through the indicators. The results show that the natural gas prices visibility graph network (NGP-VGN) is of small-world and scale-free properties simultaneously. After random rearrangement of original price time series, the degree distribution of network becomes exponential distribution, different from the original ones. This means that, the original price time series is of long-range negative correlation fractal characteristic. In addition, nodes with large degree correspond to significant geopolitical or economic events. Communities correspond to time cycles in visibility graph network. The cycles of time series and the impact scope of hubs can be found by community structure partition.

  11. Sustainability Assessment of the Natural Gas Industry in China Using Principal Component Analysis

    Directory of Open Access Journals (Sweden)

    Xiucheng Dong

    2015-05-01

    Full Text Available Under pressure toward carbon emission reduction and air protection, China has accelerated energy restructuring by greatly improving the supply and consumption of natural gas in recent years. However, several issues with the sustainable development of the natural gas industry in China still need in-depth discussion. Therefore, based on the fundamental ideas of sustainable development, industrial development theories and features of the natural gas industry, a sustainable development theory is proposed in this thesis. The theory consists of five parts: resource, market, enterprise, technology and policy. The five parts, which unite for mutual connection and promotion, push the gas industry’s development forward together. Furthermore, based on the theoretical structure, the Natural Gas Industry Sustainability Index in China is established and evaluated via the Principal Component Analysis (PCA method. Finally, a conclusion is reached: that the sustainability of the natural gas industry in China kept rising from 2008 to 2013, mainly benefiting from increasing supply and demand, the enhancement of enterprise profits, technological innovation, policy support and the optimization and reformation of the gas market.

  12. Economic evaluation and market analysis for natural gas utilization. Topical report

    International Nuclear Information System (INIS)

    Hackworth, J.H.; Koch, R.W.; Rezaiyan, A.J.

    1995-04-01

    During the past decade, the U.S. has experienced a surplus gas supply. Future prospects are brightening because of increased estimates of the potential size of undiscovered gas reserves. At the same time, U.S. oil reserves and production have steadily declined, while oil imports have steadily increased. Reducing volume growth of crude oil imports was a key objective of the Energy Policy Act of 1992. Natural gas could be an important alternative energy source to liquid products derived from crude oil to help meet market demand. The purpose of this study was to (1) analyze three energy markets to determine whether greater use could be made of natural gas or its derivatives and (2) determine whether those products could be provided on an economically competitive basis. The following three markets were targeted for possible increases in gas use: transportation fuels, power generation, and chemical feedstock. Gas-derived products that could potentially compete in these three markets were identified, and the economics of the processes for producing those products were evaluated. The processes considered covered the range from commercial to those in early stages of process development. The analysis also evaluated the use of both high-quality natural gas and lower-quality gases containing CO 2 and N 2 levels above normal pipeline quality standards

  13. Quantitative analysis of bowel gas by plain abdominal radiograph combined with computer image processing

    International Nuclear Information System (INIS)

    Gao Yan; Peng Kewen; Zhang Houde; Shen Bixian; Xiao Hanxin; Cai Juan

    2003-01-01

    Objective: To establish a method for quantitative analysis of bowel gas by plain abdominal radiograph and computer graphics. Methods: Plain abdominal radiographs in supine position from 25 patients with irritable bowel syndrome (IBS) and 20 health controls were studied. A gastroenterologist and a radiologist independently conducted the following procedure on each radiograph. After the outline of bowel gas was traced by axe pen, the radiograph was digitized by a digital camera and transmitted to the computer with Histogram software. The total gas area was determined as the pixel value on images. The ratio of the bowel gas quantity to the pixel value in the region surrounded by a horizontal line tangential to the superior pubic symphysis margin, a horizontal line tangential to the tenth dorsal vertebra inferior margin, and the lateral line tangential to the right and left anteriosuperior iliac crest, was defined as the gas volume score (GVS). To examine the sequential reproducibility, a second plain abdominal radiograph was performed in 5 normal controls 1 week later, and the GVS were compared. Results: Bowel gas was easily identified on the plain abdominal radiograph. Both large and small intestine located in the selected region. Both observers could finish one radiographic measurement in less than 10 mins. The correlation coefficient between the two observers was 0.986. There was no statistical difference on GVS between the two sequential radiographs in 5 health controls. Conclusion: Quantification of bowel gas based on plain abdominal radiograph and computer is simple, rapid, and reliable

  14. Spectral Analysis of Moderately Charged Rare-Gas Atoms

    Directory of Open Access Journals (Sweden)

    Jorge Reyna Almandos

    2017-03-01

    Full Text Available This article presents a review concerning the spectral analysis of several ions of neon, argon, krypton and xenon, with impact on laser studies and astrophysics that were mainly carried out in our collaborative groups between Argentina and Brazil during many years. The spectra were recorded from the vacuum ultraviolet to infrared regions using pulsed discharges. Semi-empirical approaches with relativistic Hartree–Fock and Dirac-Fock calculations were also included in these investigations. The spectral analysis produced new classified lines and energy levels. Lifetimes and oscillator strengths were also calculated.

  15. Impact of comprehensive two-dimensional gas chromatography with mass spectrometry on food analysis.

    Science.gov (United States)

    Tranchida, Peter Q; Purcaro, Giorgia; Maimone, Mariarosa; Mondello, Luigi

    2016-01-01

    Comprehensive two-dimensional gas chromatography with mass spectrometry has been on the separation-science scene for about 15 years. This three-dimensional method has made a great positive impact on various fields of research, and among these that related to food analysis is certainly at the forefront. The present critical review is based on the use of comprehensive two-dimensional gas chromatography with mass spectrometry in the untargeted (general qualitative profiling and fingerprinting) and targeted analysis of food volatiles; attention is focused not only on its potential in such applications, but also on how recent advances in comprehensive two-dimensional gas chromatography with mass spectrometry will potentially be important for food analysis. Additionally, emphasis is devoted to the many instances in which straightforward gas chromatography with mass spectrometry is a sufficiently-powerful analytical tool. Finally, possible future scenarios in the comprehensive two-dimensional gas chromatography with mass spectrometry food analysis field are discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Interring Gas Dynamic Analysis of Piston in a Diesel Engine considering the Thermal Effect

    Directory of Open Access Journals (Sweden)

    Wanyou Li

    2015-01-01

    Full Text Available Understanding the interaction between ring dynamics and gas transport in ring pack systems is crucial and needs to be imperatively studied. The present work features detailed interring gas dynamics of piston ring pack behavior in internal combustion engines. The model is developed for a ring pack with four rings. The dynamics of ring pack are simulated. Due to the fact that small changes in geometry of the grooves and lands would have a significant impact on the interring gas dynamics, the thermal deformation of piston has been considered during the ring pack motion analysis in this study. In order to get the temperature distribution of piston head more quickly and accurately, an efficient method utilizing the concept of inverse heat conduction is presented. Moreover, a sensitive analysis based on the analysis of partial regression coefficients is presented to investigate the effect of groove parameters on blowby.

  17. Analysis of spatial and temporal spectra of liquid film surface in annular gas-liquid flow

    Science.gov (United States)

    Alekseenko, Sergey; Cherdantsev, Andrey; Heinz, Oksana; Kharlamov, Sergey; Markovich, Dmitriy

    2013-09-01

    Wavy structure of liquid film in annular gas-liquid flow without liquid entrainment consists of fast long-living primary waves and slow short-living secondary waves. In present paper, results of spectral analysis of this wavy structure are presented. Application of high-speed LIF technique allowed us to perform such analysis in both spatial and temporal domains. Power spectra in both domains are characterized by one-humped shape with long exponential tail. Influence of gas velocity, liquid Reynolds number, liquid viscosity and pipe diameter on frequency of the waves is investigated. When gravity effect is much lesser than the shear stress, similarity of power spectra at different gas velocities is observed. Using combination of spectral analysis and identification of characteristic lines of primary waves, frequency of generation of secondary waves by primary waves is measured.

  18. Life Cycle Energy Consumption and Greenhouse Gas Emissions Analysis of Natural Gas-Based Distributed Generation Projects in China

    Directory of Open Access Journals (Sweden)

    Hansi Liu

    2017-10-01

    Full Text Available In this paper, we used the life-cycle analysis (LCA method to evaluate the energy consumption and greenhouse gas (GHG emissions of natural gas (NG distributed generation (DG projects in China. We took the China Resources Snow Breweries (CRSB NG DG project in Sichuan province of China as a base scenario and compared its life cycle energy consumption and GHG emissions performance against five further scenarios. We found the CRSB DG project (all energy input is NG can reduce GHG emissions by 22%, but increase energy consumption by 12% relative to the scenario, using coal combined with grid electricity as an energy input. The LCA also indicated that the CRSB project can save 24% of energy and reduce GHG emissions by 48% relative to the all-coal scenario. The studied NG-based DG project presents major GHG emissions reduction advantages over the traditional centralized energy system. Moreover, this reduction of energy consumption and GHG emissions can be expanded if the extra electricity from the DG project can be supplied to the public grid. The action of combining renewable energy into the NG DG system can also strengthen the dual merit of energy conservation and GHG emissions reduction. The marginal CO2 abatement cost of the studied project is about 51 USD/ton CO2 equivalent, which is relatively low. Policymakers are recommended to support NG DG technology development and application in China and globally to boost NG utilization and control GHG emissions.

  19. The gas market and sector in France. Situation and predictions 2018 - Sector and competitive analysis

    International Nuclear Information System (INIS)

    2017-01-01

    Through a detailed analysis of market determining factors, of evolutions of supply and demand, and of major events in firms life, this set of two reports proposes an analysis of the recent situation of the gas sector and of the evolutions of the competitive game. The first report on situation and predictions which is updated three times a year, proposes a synthesis on the consequences of the evolution of the economic environment, on major trends noticed for the sector, and on predictable evolutions. It proposes the most recent predictions regarding natural gas consumption in France and the turnover of the gas sector. It highlights recent events for companies of the sector: takeovers, investments, restructuring, introduction of new products, and so on. It proposes a sector-based dashboard which contains all the critical figures useful to analyse the sector situation (activity determining factors, key figures for the sector and its environment). The second report (the annual one) proposes an overview of trends and competition within the gas sector. It gives an overview of some basic aspects of the activity (sector organisation, gas categories, main customer markets, gas consumption in industry), and of its determining factors, analyses the sector environment (sites connected to the natural gas network, evolution of average temperatures in France, production by chemical industry, by the food industry, and by metallurgy and oil refining, thermal production of electricity, regulatory evolution regarding supports to energy efficiency, and new opportunities). The evolution of the sector activity is analysed through its trends and indicators (turnovers, gas consumption, butane-propane deliveries, wholesale prices, regulated tariffs). The economic structure is also analysed: aspects related to the upstream part (extraction, injection of biogas, natural gas main input and output points, transport and storage, natural gas distribution), and aspects related to gas provision

  20. Helicopter Gas Turbine Engine Performance Analysis : A Multivariable Approach

    NARCIS (Netherlands)

    Arush, Ilan; Pavel, M.D.

    2017-01-01

    Helicopter performance relies heavily on the available output power of the engine(s) installed. A simplistic single-variable analysis approach is often used within the flight-testing community to reduce raw flight-test data in order to predict the available output power under different atmospheric

  1. PRINCIPAL COMPONENT ANALYSIS STUDIES OF TURBULENCE IN OPTICALLY THICK GAS

    Energy Technology Data Exchange (ETDEWEB)

    Correia, C.; Medeiros, J. R. De [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59072-970, Natal (Brazil); Lazarian, A. [Astronomy Department, University of Wisconsin, Madison, 475 N. Charter St., WI 53711 (United States); Burkhart, B. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St, MS-20, Cambridge, MA 02138 (United States); Pogosyan, D., E-mail: caioftc@dfte.ufrn.br [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON (Canada)

    2016-02-20

    In this work we investigate the sensitivity of principal component analysis (PCA) to the velocity power spectrum in high-opacity regimes of the interstellar medium (ISM). For our analysis we use synthetic position–position–velocity (PPV) cubes of fractional Brownian motion and magnetohydrodynamics (MHD) simulations, post-processed to include radiative transfer effects from CO. We find that PCA analysis is very different from the tools based on the traditional power spectrum of PPV data cubes. Our major finding is that PCA is also sensitive to the phase information of PPV cubes and this allows PCA to detect the changes of the underlying velocity and density spectra at high opacities, where the spectral analysis of the maps provides the universal −3 spectrum in accordance with the predictions of the Lazarian and Pogosyan theory. This makes PCA a potentially valuable tool for studies of turbulence at high opacities, provided that proper gauging of the PCA index is made. However, we found the latter to not be easy, as the PCA results change in an irregular way for data with high sonic Mach numbers. This is in contrast to synthetic Brownian noise data used for velocity and density fields that show monotonic PCA behavior. We attribute this difference to the PCA's sensitivity to Fourier phase information.

  2. Quantifying tight-gas sandstone permeability via critical path analysis

    Science.gov (United States)

    Rock permeability has been actively investigated over the past several decades by the geosciences community. However, its accurate estimation still presents significant technical challenges, especially in spatially complex rocks. In this letter, we apply critical path analysis (CPA) to estimate perm...

  3. PRINCIPAL COMPONENT ANALYSIS STUDIES OF TURBULENCE IN OPTICALLY THICK GAS

    International Nuclear Information System (INIS)

    Correia, C.; Medeiros, J. R. De; Lazarian, A.; Burkhart, B.; Pogosyan, D.

    2016-01-01

    In this work we investigate the sensitivity of principal component analysis (PCA) to the velocity power spectrum in high-opacity regimes of the interstellar medium (ISM). For our analysis we use synthetic position–position–velocity (PPV) cubes of fractional Brownian motion and magnetohydrodynamics (MHD) simulations, post-processed to include radiative transfer effects from CO. We find that PCA analysis is very different from the tools based on the traditional power spectrum of PPV data cubes. Our major finding is that PCA is also sensitive to the phase information of PPV cubes and this allows PCA to detect the changes of the underlying velocity and density spectra at high opacities, where the spectral analysis of the maps provides the universal −3 spectrum in accordance with the predictions of the Lazarian and Pogosyan theory. This makes PCA a potentially valuable tool for studies of turbulence at high opacities, provided that proper gauging of the PCA index is made. However, we found the latter to not be easy, as the PCA results change in an irregular way for data with high sonic Mach numbers. This is in contrast to synthetic Brownian noise data used for velocity and density fields that show monotonic PCA behavior. We attribute this difference to the PCA's sensitivity to Fourier phase information

  4. Gas-phase polynuclear aromatic hydrocarbons (PAH) in vehicle exhaust: A method for collection and analysis

    International Nuclear Information System (INIS)

    Seigl, W.O.; Chladek, E.

    1990-01-01

    Gas-phase polynuclear aromatic hydrocarbons (PAH) are emitted at low levels in vehicle exhaust compared to other hydrocarbon emissions. A method has been developed involving the trapping of gas phase emissions on Tenax, a macrorecticular porous polymer, followed by thermal desorption onto a capillary gas chromatography column. Gas chromatography/mass spectrometry (GC/MS) was used for the chemical analysis. A detection limit of 0.05 ng was achieved for several gas-phase PAH. This high sensitivity enables the speciation and quantitation of gas-phase PAH collected from a dilution tube during standard driving (test) cycles. The method was demonstrated for the analysis of 9 PAH in the exhaust from a 1987 vehicle (with and without catalyst) during the hot start transient phase of the EPA urban dynamometer driving schedule. The PAH measured include naphthalene, 2-methyl- and 1-methylnaphthalene, biphenyl, fluorene, phenanthrene, anthracene, fluoranthene and pyrene. The four most abundant PAH observed are naphthalene, 2-methyl and 1-methylnaphthalene, and biphenyl, in that order

  5. Analysis of gas-liquid metal two-phase flows using a reactor safety analysis code SIMMER-III

    International Nuclear Information System (INIS)

    Suzuki, Tohru; Tobita, Yoshiharu; Kondo, Satoru; Saito, Yasushi; Mishima, Kaichiro

    2003-01-01

    SIMMER-III, a safety analysis code for liquid-metal fast reactors (LMFRs), includes a momentum exchange model based on conventional correlations for ordinary gas-liquid flows, such as an air-water system. From the viewpoint of safety evaluation of core disruptive accidents (CDAs) in LMFRs, we need to confirm that the code can predict the two-phase flow behaviors with high liquid-to-gas density ratios formed during a CDA. In the present study, the momentum exchange model of SIMMER-III was assessed and improved using experimental data of two-phase flows containing liquid metal, on which fundamental information, such as bubble shapes, void fractions and velocity fields, has been lacking. It was found that the original SIMMER-III can suitably represent high liquid-to-gas density ratio flows including ellipsoidal bubbles as seen in lower gas fluxes. In addition, the employment of Kataoka-Ishii's correlation has improved the accuracy of SIMMER-III for gas-liquid metal flows with cap-shape bubbles as identified in higher gas fluxes. Moreover, a new procedure, in which an appropriate drag coefficient can be automatically selected according to bubble shape, was developed. Through this work, the reliability and the precision of SIMMER-III have been much raised with regard to bubbly flows for various liquid-to-gas density ratios

  6. A physicochemical mechanism of chemical gas sensors using an AC analysis.

    Science.gov (United States)

    Moon, Jaehyun; Park, Jin-Ah; Lee, Su-Jae; Lee, Jeong-Ik; Zyung, Taehyong; Shin, Eui-Chol; Lee, Jong-Sook

    2013-06-21

    Electrical modeling of the chemical gas sensors was successfully applied to TiO2 nanofiber gas sensors by developing an equivalent circuit model where the junction capacitance as well as the resistance can be separated from the comparable stray capacitance. The Schottky junction impedance exhibited a characteristic skewed arc described by a Cole-Davidson function, and the variation of the fit and derived parameters with temperature, bias, and NO2 gas concentration indicated definitely a physicochemical sensing mechanism based on the Pt|TiO2 Schottky junctions against the conventional supposition of the enhanced sensitivity in nanostructured gas sensors with high grain boundary/surface area. Analysis on a model Pt|TiO2|Pt structure also confirmed the characteristic impedance response of TiO2 nanofiber sensors.

  7. Computational analysis of transient gas release from a high pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Pedro, G.; Oshkai, P.; Djilali, N. [Victoria Univ., BC (Canada). Inst. for Integrated Energy Systems; Penau, F. [CERAM Euro-American Inst. of Technology, Sophia Antipolis (France)

    2006-07-01

    Gas jets exiting from compressed vessels can undergo several regimes as the pressure in the vessel decreases, and a greater understanding of the characteristics of gas jets is needed to determine safety requirements in the transport, distribution, and use of hydrogen. This paper provided a study of the bow shock waves that typically occur during the initial stage of a gas jet incident. The transient behaviour of an initiated jet was investigated using unsteady, compressible flow simulations. The gas was considered to be ideal, and the domain was considered to be axisymmetric. Tank pressure for the analysis was set at a value of 100 atm. Jet structure was examined, as well as the shock structures and separation due to adverse pressure gradients at the nozzle. Shock structure displacement was also characterized.

  8. Modeling and parametric analysis of hollow fiber membrane system for carbon capture from multicomponent flue gas

    KAUST Repository

    Khalilpour, Rajab

    2011-08-12

    The modeling and optimal design/operation of gas membranes for postcombustion carbon capture (PCC) is presented. A systematic methodology is presented for analysis of membrane systems considering multicomponent flue gas with CO 2 as target component. Simplifying assumptions is avoided by namely multicomponent flue gas represented by CO 2/N 2 binary mixture or considering the co/countercurrent flow pattern of hollow-fiber membrane system as mixed flow. Optimal regions of flue gas pressures and membrane area were found within which a technoeconomical process system design could be carried out. High selectivity was found to not necessarily have notable impact on PCC membrane performance, rather, a medium selectivity combined with medium or high permeance could be more advantageous. © 2011 American Institute of Chemical Engineers (AIChE).

  9. An analysis on social cost benefit of city gas safety supervision system - concentrated on estimating the intended amount paid about gas safety of households using city gas

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong Sung [Korea Energy Economics Institute, Euiwang (Korea)

    1999-04-01

    With the increase of convenient and clean gas fuel consumption, the danger of gas safety accident is also increasing. Therefore, now is the time for requiring many thoughtful concerns and cares for the prevention of gas accident. In this study, the perception of city gas end users on use of city gas was studied and the economic value of improving gas safety was estimated by examining the intended amount paid for improving safety of city gas use. Although most of city gas end-users perceive that gas use is generally safe, they are concerned about a possibility of dander of accidents happened without any notice. On the other hand, about 97% of households using city gas know checking gas safety at a minimum, but only 60% among them are implementing self-checkup. The economic benefit of improving gas safety of city gas end-users in Korea is estimated from the lowest of 121.47 billion to the highest of 317.97 billion annually. (author). 38 refs., 5 figs., 45 tabs.

  10. Analysis of gas turbine cogeneration plants in Italy; Indagine sulla funzionalita` degli impianti di cogenerazione conturbina a gas operanti in Italia

    Energy Technology Data Exchange (ETDEWEB)

    Romani, Rino; Vignati, Sigfrido [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Energia

    1997-10-01

    The purpose of this study is to improve, by random analysis, the current knowledge about functional and running data of gas turbine cogeneration plants in Italy. The analysis consider simple and combined cycle gas turbines plant with electric power less 30.000 k W per unit and involves a sample of 44 units according to a randomized model consisting of 112 gas turbines. The collected data show different plant selection criteria, energy performances, reliability and availability values as well as maintenance costs. These data support some general suggestions and recommendations for a better selection and utilization of these plants.

  11. Analysis of Discharged Gas from Incinerator using Simulated Organic Solution

    International Nuclear Information System (INIS)

    Kim, Seungil; Kim, Hyunki; Heo, Jun; Kang, Dukwon; Kim, Yunbok; Kwon, Youngbock

    2014-01-01

    is controlled from 800 .deg. c to 930 .deg. C using temperature controller. The concentration of gaseous pollutants released by incinerating simulated organic waste is satisfied with Clean Air Conservation Act, Notification of Nuclear Safety Commission, Persistent Organic Pollutants Control Act and related statute. The incinerator used in this experiment is not object of regulation but the concentration of dioxin released from incinerator, 0.007ng-TEQ/Sm 3 , could be ignored because it is just 7%, in comparison with the limit of exhaust standard, 0.1ng-TEQ/Sm 3 . This is due to the rapid cooling of exhaust gas using heat-exchanger

  12. Analysis of Discharged Gas from Incinerator using Simulated Organic Solution

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seungil; Kim, Hyunki; Heo, Jun; Kang, Dukwon [HaJI Co., Ltd., Radiation Eng. Center, Siheung (Korea, Republic of); Kim, Yunbok; Kwon, Youngbock [KORAD, Daejeon (Korea, Republic of)

    2014-05-15

    is controlled from 800 .deg. c to 930 .deg. C using temperature controller. The concentration of gaseous pollutants released by incinerating simulated organic waste is satisfied with Clean Air Conservation Act, Notification of Nuclear Safety Commission, Persistent Organic Pollutants Control Act and related statute. The incinerator used in this experiment is not object of regulation but the concentration of dioxin released from incinerator, 0.007ng-TEQ/Sm{sup 3}, could be ignored because it is just 7%, in comparison with the limit of exhaust standard, 0.1ng-TEQ/Sm{sup 3}. This is due to the rapid cooling of exhaust gas using heat-exchanger.

  13. Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

    OpenAIRE

    Shams Bilal; Yao Jun; Zhang Kai; Zhang Lei

    2017-01-01

    Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large...

  14. Self-organizing nanodot structures on InP surfaces evolving under low-energy ion irradiation: analysis of morphology and composition.

    Science.gov (United States)

    Radny, Tobias; Gnaser, Hubert

    2014-01-01

    Surfaces of InP were bombarded by 1.9 keV Ar(+) ions under normal incidence. The total accumulated ion fluence Φ the samples were exposed to was varied from 1 × 10(17) cm(-2) to 3 × 10(18) cm(-2), and ion fluxes f of (0.4 - 2) × 10(14) cm(-2) s(-1) were used. The surface morphology resulting from these ion irradiations was examined by atomic force microscopy (AFM). Generally, nanodot structures are formed on the surface; their dimensions (diameter, height and separation), however, were found to depend critically on the specific bombardment conditions. As a function of ion fluence, the mean radius r, height h, and spacing l of the dots can be fitted by power-law dependences: r ∝ Φ(0.40), h ∝ Φ(0.48), and l ∝ Φ(0.19). In terms of ion flux, there appears to exist a distinct threshold: below f ~ (1.3 ± 0.2) × 10(14) cm(-2) s(-1), no ordering of the dots exists and their size is comparatively small; above that value of f, the height and radius of the dots becomes substantially larger (h ~ 40 nm and r ~ 50 nm). This finding possibly indicates that surface diffusion processes could be important. In order to determine possible local compositional changes in these nanostructures induced by ion impact, selected samples were prepared for atom probe tomography (APT). The results indicate that APT can provide analytical information on the composition of individual InP nanodots. By means of 3D APT data, the surface region of such nanodots evolving under ion bombardment could be examined with atomic spatial resolution. At the InP surface, the values of the In/P concentration ratio are distinctly higher over a distance of approximately 1 nm and amount to 1.3 to 1.7.

  15. An assessment of gas impact on geological repository. Methodology and material property of gas migration analysis in engineered barrier system

    International Nuclear Information System (INIS)

    Yamamoto, Mikihiko; Mihara, Morihiro; Ooi, Takao

    2004-01-01

    Gas production in a geological repository has potential hazard, as overpressurisation and enhanced release of radionuclides. Amongst data needed for assessment of gas impact, gas migration properties of engineered barriers, focused on clayey and cementitious material, was evaluated in this report. Gas injection experiments of saturated bentonite sand mixture, mortar and cement paste were carried out. In the experiments, gas entry phenomenon and gas outflow rate were observed for these materials. Based on the experimental results, two-phase flow parameters were evaluated quantitatively. A conventional continuum two-phase flow model, which is only practically used multidimensional multi-phase flow model, was applied to fit the experimental results. The simulation results have been in good agreement with the gas entry time and the outflow flux of gas and water observed in the experiments. It was confirmed that application of the continuum two-phase flow model to gas migration in cementitious materials provides sufficient degree of accuracy for assessment of repository performance. But, for sand bentonite mixture, further extension of basic two-phase flow model is needed especially for effect of stress field. Furthermore, gas migration property of other barrier materials, including rocks, but long-term gas injection test, clarification of influence of chemicals environment and large-scale gas injection test is needed for multi-barrier assessment tool development and their verification. (author)

  16. Integrated failure probability estimation based on structural integrity analysis and failure data: Natural gas pipeline case

    International Nuclear Information System (INIS)

    Dundulis, Gintautas; Žutautaitė, Inga; Janulionis, Remigijus; Ušpuras, Eugenijus; Rimkevičius, Sigitas; Eid, Mohamed

    2016-01-01

    In this paper, the authors present an approach as an overall framework for the estimation of the failure probability of pipelines based on: the results of the deterministic-probabilistic structural integrity analysis (taking into account loads, material properties, geometry, boundary conditions, crack size, and defected zone thickness), the corrosion rate, the number of defects and failure data (involved into the model via application of Bayesian method). The proposed approach is applied to estimate the failure probability of a selected part of the Lithuanian natural gas transmission network. The presented approach for the estimation of integrated failure probability is a combination of several different analyses allowing us to obtain: the critical crack's length and depth, the failure probability of the defected zone thickness, dependency of the failure probability on the age of the natural gas transmission pipeline. A model's uncertainty analysis and uncertainty propagation analysis are performed, as well. - Highlights: • Degradation mechanisms of natural gas transmission pipelines. • Fracture mechanic analysis of the pipe with crack. • Stress evaluation of the pipe with critical crack. • Deterministic-probabilistic structural integrity analysis of gas pipeline. • Integrated estimation of pipeline failure probability by Bayesian method.

  17. A multi-sectoral decomposition analysis of city-level greenhouse gas emissions: Case study of Tianjin, China

    International Nuclear Information System (INIS)

    Kang, Jidong; Zhao, Tao; Liu, Nan; Zhang, Xin; Xu, Xianshuo; Lin, Tao

    2014-01-01

    To better understand how city-level greenhouse gas (GHG) emissions have evolved, we performed a multi-sectoral decomposition analysis to disentangle the GHG emissions in Tianjin from 2001 to 2009. Five sectors were considered, including the agricultural, industrial, transportation, commercial and other sectors. An industrial sub-sector decomposition analysis was further performed in the six high-emission industrial branches. The results show that, for all five sectors in Tianjin, economic growth was the most important factor driving the increase in emissions, while energy efficiency improvements were primarily responsible for the decrease in emissions. In comparison, the influences from energy mix shift and emission coefficient changes were relatively marginal. The disaggregated decomposition in the industry further revealed that energy efficiency improvement has been widely achieved in the industrial branches, which was especially true for the Smelting and Pressing of Ferrous Metals and Chemical Raw Materials and Chemical Products sub-sectors. However, the energy efficiency declined in a few branches, e.g., Petroleum Processing and Coking Products. Moreover, the increased emissions related to industrial structure shift were primarily due to the expansion of Smelting and Pressing of Ferrous Metals; its share in the total industry output increased from 5.62% to 16.1% during the examined period. - Highlights: • We perform the LMDI analysis on the emissions in five sectors of Tianjin. • Economic growth was the most important factor for the emissions increase. • Energy efficiency improvements mainly contributed to the emission decrease. • Negative energy intensity effect was observed in most of the industrial sub-sectors. • Industrial structure change largely resulted in emission increase

  18. An analysis of main factors in electron beam flue gas purification

    International Nuclear Information System (INIS)

    Zhang Ming; Xu Guang

    2003-01-01

    Electron beam flue gas purification method is developing very quickly in recent years. Based on the experiment setting for electron beam flue gas purification in Institute of Nuclear Energy and Technology, Tsinghua University, how the technique factors affect the ratio of desulphurization and denitrogenation are described. Radiation dose (D), temperature (T), humidity (H), pour ammonia quantity (α) and initial concentration of SO 2 (C SO 2 ) and NO x (C NO x ) are main factors influencing flue gas purification. Using the methods of correlation analysis and regression analysis, the primary effect factors are found out and the regression equations are set to optimize the system process, predigest the system structure and to forecast the experimental results. (authors)

  19. Basic chemically recuperated gas turbines--power plant optimization and thermodynamics second law analysis

    International Nuclear Information System (INIS)

    Alves, Lourenco Gobira; Nebra, Silvia Azucena

    2004-01-01

    One of the proposals to increase the performance of the gas turbines is to improve chemical recuperated cycle. In this cycle, the heat in the turbine exhaust gases is used to heat and modify the chemical characteristics of the fuel. One mixture of natural gas and steam receives heat from the exhaust turbine gases; the mixture components react among themselves producing hot synthesis gas. In this work, an analysis and nonlinear optimization of the cycle were made in order to investigate the temperature and pressure influence on the global cycle performance. The chemical composition in the reformer was assumed according to chemical equilibrium equations, which presents good agreement with data from literature. The mixture of hot gases was treated like ideal gases. The maximum net profit was achieved and a thermodynamic second law analysis was made in order to detect the greatest sources of irreversibility

  20. Application of gas chromatography to analysis of spirit-based alcoholic beverages.

    Science.gov (United States)

    Wiśniewska, Paulina; Śliwińska, Magdalena; Dymerski, Tomasz; Wardencki, Waldemar; Namieśnik, Jacek

    2015-01-01

    Spirit-based beverages are alcoholic drinks; their production processes are dependent on the type and origin of raw materials. The composition of this complex matrix is difficult to analyze, and scientists commonly choose gas chromatography techniques for this reason. With a wide selection of extraction methods and detectors it is possible to provide qualitative and quantitative analysis for many chemical compounds with various functional groups. This article describes different types of gas chromatography techniques and their most commonly used associated extraction techniques (e.g., LLE, SPME, SPE, SFE, and SBME) and detectors (MS, TOFMS, FID, ECD, NPD, AED, O or EPD). Additionally, brief characteristics of internationally popular spirit-based beverages and application of gas chromatography to the analysis of selected alcoholic drinks are presented.

  1. Sensitivity analysis of a light gas oil deep hydrodesulfurization process via catalytic distillation

    Energy Technology Data Exchange (ETDEWEB)

    Rosales-Quintero, A.; Vargas-Villamil, F.D. [Prog. de Matematicas Aplicadas y Computacion, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, Mexico, D.F. 07330 (Mexico); Arce-Medina, E. [Instituto Politecnico Nacional, ESIQIE, Ed. 8 Col. Lindavista, Mexico, D.F. 07738 (Mexico)

    2008-01-30

    In this work, a sensitivity analysis of a light gas oil deep hydrodesulfurization catalytic distillation column is presented. The aim is to evaluate the effects of various parameters and operating conditions on the organic sulfur compound elimination by using a realistic light gas oil fraction. The hydrocarbons are modeled using pseudocompounds, while the organic sulfur compounds are modeled using model compounds, i.e., dibenzothiophene (DBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT). These are among the most refractive sulfur compounds present in the oil fractions. A sensitivity analysis is discussed for the reflux ratio, bottom flow rate, condenser temperature, hydrogen and gas oil feed stages, catalyst loading, the reactive, stripping, and rectifying stages, feed disturbances, and multiple feeds. The results give insight into the qualitative effect of some of the operating variables and disturbances on organic sulfur elimination. In addition, they show that special attention must be given to the bottom flow rate and LGO feed rate control. (author)

  2. Life cycle planning: An evolving concept

    International Nuclear Information System (INIS)

    Moore, P.J.R.; Gorman, I.G.

    1994-01-01

    Life-cycle planning is an evolving concept in the management of oil and gas projects. BHP Petroleum now interprets this idea to include all development planning from discovery and field appraisal to final abandonment and includes safety, environmental, technical, plant, regulatory, and staffing issues. This article describes in the context of the Timor Sea, how despite initial successes and continuing facilities upgrades, BHPP came to perceive that current operations could be the victim of early development successes, particularly in the areas of corrosion and maintenance. The search for analogies elsewhere lead to the UK North Sea, including the experiences of Britoil and BP, both of which performed detailed Life of Field studies in the later eighties. These materials have been used to construct a format and content for total Life-cycle plans in general and the social changes required to ensure their successful application in Timor Sea operations and deployment throughout Australia

  3. Investigation of thiol derivatized gold nanoparticle sensors for gas analysis

    Science.gov (United States)

    Stephens, Jared S.

    Analysis of volatile organic compounds (VOCs) in air and exhaled breath by sensor array is a very useful testing technique. It can provide non-invasive, fast, inexpensive testing for many diseases. Breath analysis has been very successful in identifying cancer and other diseases by using a chemiresistor sensor or array with gold nanoparticles to detect biomarkers. Acetone is a biomarker for diabetes and having a portable testing device could help to monitor diabetic and therapeutic progress. An advantage to this testing method is it is conducted at room temperature instead of 200 degrees Celsius. 3. The objective of this research is to determine the effect of thiol derivatized gold nanoparticles based on sensor(s) detection of VOCs. The VOCs to be tested are acetone, ethanol, and a mixture of acetone and ethanol. Each chip is tested under all three VOCs and three concentration levels (0.1, 1, and 5.0 ppm). VOC samples are used to test the sensors' ability to detect and differentiate VOCs. Sensors (also referred to as a chip) are prepared using several types of thiol derivatized gold nanoparticles. The factors are: thiol compound and molar volume loading of the thiol in synthesis. The average resistance results are used to determine the VOC selectivity of the sensors tested. The results show a trend of increasing resistance as VOC concentration is increased relative to dry air; which is used as baseline for VOCs. Several sensors show a high selectivity to one or more VOCs. Overall the 57 micromoles of 4-methoxy-toluenethiol sensor shows the strongest selectivity for VOCs tested. 3. Gerfen, Kurt. 2012. Detection of Acetone in Air Using Silver Ion Exchanged ZSM-5 and Zinc Oxide Sensing Films. Master of Science thesis, University of Louisville.

  4. Chemical sensors for breath gas analysis: the latest developments at the Breath Analysis Summit 2013.

    Science.gov (United States)

    Tisch, Ulrike; Haick, Hossam

    2014-06-01

    Profiling the body chemistry by means of volatile organic compounds (VOCs) in the breath opens exciting new avenues in medical diagnostics. Gas sensors could provide ideal platforms for realizing portable, hand-held breath testing devices in the near future. This review summarizes the latest developments and applications in the field of chemical sensors for diagnostic breath testing that were presented at the Breath Analysis Summit 2013 in Wallerfangen, Germany. Considerable progress has been made towards clinically applicable breath testing devices, especially by utilizing chemo-sensitive nanomaterials. Examples of several specialized breath testing applications are presented that are either based on stand-alone nanomaterial-based sensors being highly sensitive and specific to individual breath compounds over others, or on combinations of several highly specific sensors, or on experimental nanomaterial-based sensors arrays. Other interesting approaches include the adaption of a commercially available MOx-based sensor array to indirect breath testing applications, using a sample pre-concentration method, and the development of compact integrated GC-sensor systems. The recent trend towards device integration has led to the development of fully integrated prototypes of point-of-care devices. We describe and compare the performance of several prototypes that are based on different sensing technologies and evaluate their potential as low-cost and readily available next-generation medical devices.

  5. Fatigue life analysis of cracked gas receiver of emergency cut-off system in gas gathering station

    Science.gov (United States)

    Hu, Junzhi; Zhou, Jiyong; Li, Siyuan

    2017-06-01

    Small-scale air compressor and gas receiver are used as the driving gas of the emergency cut-off system in gas gathering station. Operation of block valve is ensured by starting and stopping compressor automatically. The frequent start-stop of compressor and the pressure fluctuation pose a threat to the service life of gas receiver, and then affect normal operation of the emergency cut-off system and security of gas gathering station. In this paper, the fatigue life of a pressure vessel with axial semi-elliptical surface crack in the inner wall is analyzed under the varying pressure by means of the theory of fracture mechanics. The influences of the amplitude of pressure fluctuation and the initial crack size on the residual life of gas receiver are discussed. It provides a basis for setting the working parameters of gas receiver of emergency cut-off system and determining the maintenance cycle.

  6. Optimization of gas mixing system of premixed burner based on CFD analysis

    International Nuclear Information System (INIS)

    Zhang, Tian-Hu; Liu, Feng-Guo; You, Xue-Yi

    2014-01-01

    Highlights: • New multi-ejectors gas mixing system for premixed combustion burner is provided. • Two measures are proposed to improve the flow uniformity at the outlet of GMS. • Small improvement of uniformity induces significant decrease of pollutant emission. • Uniformity of velocity and fuel–gas mixing of ejector increases 234.2% and 2.9%. • Uniformity of flow rate and fuel–gas mixing of ejectors increases 1.9% and 2.2%. - Abstract: The optimization of gas mixing system (GMS) of premixed burner is presented by Computational Fluid Dynamics (CFD) and the uniformity at the outlet of GMS is proved experimentally to have strong influence on pollutant emission. To improve the uniformity at the outlet of GMS, the eleven distribution orifice plates and a diversion plate are introduced. The quantified analysis shows that the uniformity at the outlet of GMS is improved significantly. With applying the distribution orifice plates, the uniformity of velocity and fuel–gas mixing of single ejector is increased by 234.2% and 2.9%, respectively. With applying the diversion plate, the uniformity of flow rate and fuel–gas mixing of different ejectors is increased by 1.9% and 2.2%, respectively. The optimal measures and geometrical parameters provide an applicable guidance for the design of commercial premixed burner

  7. Economic and reliability analysis in determining a programme for the technological renovation of gas networks

    International Nuclear Information System (INIS)

    Nkokolo, F.; Pisino, F.; Vakka, L.

    1997-01-01

    Gas Distribution Companies have long paid great attention to improving the quality of gas supply service to the consumer. This has involved them in an on-going attempt to successfully define and establish a clear computer assisted replacement programme which, when drawn up on a reliability basis, may also prove cost effective. The reasons which drive any gas line replacement programme are mainly related to the necessity: to improve the gas network asset so as to face a striking expected growth in gas demand; to refurbish old distribution systems with the purpose not only to increase the reliability and continuity of gas supply but also to reduce the rate of maintenance costs due to frequent repair works; to prevent the possibility of massive replacement works for a progressing ageing of the network. This paper will present the computer assisted procedure being implemented by Italgas. It ranks well defined network areas which urgently need renewal and also have a favourable economic index for action. The results of the analysis performed on a trial model network managed by the Geographic Information System, will also be a topic for discussion. (au)

  8. Offshore Antarctic Peninsula Gas Hydrate Reservoir Characterization by Geophysical Data Analysis

    Directory of Open Access Journals (Sweden)

    Michela Giustiniani

    2010-12-01

    Full Text Available A gas hydrate reservoir, identified by the presence of the bottom simulating reflector, is located offshore of the Antarctic Peninsula. The analysis of geophysical dataset acquired during three geophysical cruises allowed us to characterize this reservoir. 2D velocity fields were obtained by using the output of the pre-stack depth migration iteratively. Gas hydrate amount was estimated by seismic velocity, using the modified Biot-Geerstma-Smit theory. The total volume of gas hydrate estimated, in an area of about 600 km2, is in a range of 16 × 109–20 × 109 m3. Assuming that 1 m3 of gas hydrate corresponds to 140 m3 of free gas in standard conditions, the reservoir could contain a total volume that ranges from 1.68 to 2.8 × 1012 m3 of free gas. The interpretation of the pre-stack depth migrated sections and the high resolution morpho-bathymetry image allowed us to define a structural model of the area. Two main fault systems, characterized by left transtensive and compressive movement, are recognized, which interact with a minor transtensive fault system. The regional geothermal gradient (about 37.5 °C/km, increasing close to a mud volcano likely due to fluid-upwelling, was estimated through the depth of the bottom simulating reflector by seismic data.

  9. Analysis of micro vibration in gas film of aerostatic guide way based on molecule collision theory

    Directory of Open Access Journals (Sweden)

    Yang Shao Hua

    2016-01-01

    Full Text Available Micro vibration of the aerostatic guide way has a significant impact on its dynamic characteristics and stability, which limits the development of pneumatic component. High pressure gas molecules have been collided with the supporting surface and the internal surface of the throttle during the flow process. Variable impulse of the surfaces aside for the gas film are affected by the changes of impulse which formed irregular impact force in horizontal and vertical direction. Micro-vibration takes place based on the natural frequency of the system and its frequency doubling. In this paper, the vibration model was established to describe the dynamic characteristics of the gas film, and the formation mechanism of micro vibration in the film is defined. Through the simulation analysis and experimental comparison, formation mechanism of the micro vibration in the gas film is confirmed. It was proposed that the micro vibration of gas film can be produced no matter whether there is a gas chamber or not in the throttle. Under the same conditions, the micro vibration of the guide way with air chamber is greater than that without any chamber. The frequency points of the vibration peaks are almost the same, as well as the vibration pattern in the frequency domain.

  10. Application of Gas Chromatographic analysis to RPC detectors in the ATLAS experiment at CERN-LHC

    CERN Document Server

    De Asmundis, R

    2007-01-01

    Starting from 2007 a large number (1200) Resistive Plate Chambers (RPC) detectors will be used as muon trigger detectors in the ATLAS Experiment at CERN-LHC accelerator. RPC are gaseous detector in which the quality and the stability of the gas mixture as well as the design of the gas supplying system, play a fundamental role in their functioning. RPC are foreseen to work more than ten years in the high radiation environment of ATLAS and the gas mixture acts really as a "lifeguard" for the detectors. For this reason a great attention has been devoted to the gas studies in order to optimize RPC performance, robustness and reliability in a high radiation environment. In this paper we describe the work done to decide how to supply and control in an optimal way the gas to the detectors, in order to ensure their best performance for a long time. The activity, based on Gas Chromatographic (GC) analysis, has been carried on a sample of final RPC working in radiation conditions much more intense than those foreseen f...

  11. Transient Analysis and Design Improvement of a Gas Turbine Rotor Based on Thermal-Mechanical Method

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2018-01-01

    Full Text Available The rotor is the core component of a gas turbine, and more than 80% of the failures in gas turbines occur in the rotor system, especially during the start-up period. Therefore, the safety assessment of the rotor during the start-up period is essential for the design of the gas turbine. In this paper, the transient equivalent stress of a gas turbine rotor under the cold start-up condition is investigated and the novel tie rod structure is introduced to reduce the equivalent stress. Firstly, a three-dimensional finite element model of the gas turbine rotor is built, and nonlinear contact behaviors such as friction are taken into account. Secondly, the convective heat transfer coefficients of the gas turbine rotor under the cold start-up condition are calculated using thermal dynamic theory. The transient analysis of the gas turbine rotor is conducted considering the thermal load, the centrifugal load, and the pretightening force. The temperature and stress distributions of the rotor under the cold start-up condition are shown in detail. In particular, the generation mechanism of maximum equivalent stress for tie rods and the change tendency of the pretightening force are illustrated in detail. The tie rod holes of the rear shaft and the turbine tie rod are the dangerous locations during the start-up period. Finally, a novel tie rod is proposed to reduce the maximum equivalent stress at the dangerous location. The maximum equivalent stress at this location is decreased by 15%. This paper provides some reference for the design of the gas turbine rotor.

  12. Electricity to natural gas competition under customer-side technological change: a marginal cost pricing analysis

    International Nuclear Information System (INIS)

    Gulli', Francesco

    2004-01-01

    This paper aims at evaluating the impact of technological change (on the customer side of the meter) on the network energy industry (electricity and natural gas). The performances of the small gas fired power technologies and the electrical reversible heat pumps have improved remarkably over the last ten years, making possible (or more viable) two opposite technological trajectories: the fully gas-based system, based on the use of small CHP (combined heat and power generation) plants, which would involve a wide decentralisation of energy supply; the fully electric-based system, based on the use of reversible electric heat pumps, which would imply increasing centralisation of energy supply. The analysis described in this paper attempts to evaluate how these two kinds of technological solutions can impact on inter-service competition when input prices are ste equals to marginal costs of supply in each stage of the electricity and natural gas industries. For this purpose, unbundled prices over time and over space are simulated. In particular the paper shows that unbundling prices over space in not very important in affecting electricity to natural gas competition and that, when prices are set equal to long-run marginal costs, the fully electric-based solution (the reversible heat pump) is by far preferable to the fully gas-based solution (the CHP gas fired small power plant). In consequence, the first best outcome of the technological change would involve increasing large power generation and imported (from the utility grid) electricity consumption. Given this framework, we have to ask ourselves why operators, regulators and legislators are so optimistic about the development of the fully gas-based solutions. In this respect, the paper suggests that market distortions (such as market power, energy taxation and inefficient pricing regulation) might have give an ambiguous representation of the optimal technological trajectory, inducing to overestimate the social value

  13. Carbohydrate analysis of hemicelluloses by gas chromatography-mass spectrometry of acteylated methyl glycosides

    DEFF Research Database (Denmark)

    Sárossy, Zsuzsa; Plackett, David; Egsgaard, Helge

    2012-01-01

    A method based on gas chromatography–mass spectrometry analysis of acetylated methyl glycosides was developed in order to analyze monosaccharides obtained from various hemicelluloses. The derivatives of monosaccharide standards, arabinose, glucose, and xylose were studied in detail and 13C...

  14. Trace analysis in the food and beverage industry by capillary gas chromatography: system performance and maintenance.

    Science.gov (United States)

    Hayes, M A

    1988-04-01

    Gas chromatography (GC) is the most widely used analytical technique in the food and beverage industry. This paper addresses the problems of sample preparation and system maintenance to ensure the most sensitive, durable, and efficient results for trace analysis by GC in this industry.

  15. Comprehensive two-dimensional gas chromatography for the analysis of organohalogenated micro-contaminants

    NARCIS (Netherlands)

    Korytar, P.; Haglund, P.; Boer, de J.; Brinkman, U.A.Th.

    2006-01-01

    We explain the principles of comprehensive two-dimensional gas chromatography (GC × GC), and discuss key instrumental aspects - with emphasis on column combinations and mass spectrometric detection. As the main item of interest, we review the potential of GC × GC for the analysis of

  16. Gas chromatography/sniffing port analysis evaluated for aroma release from rehydrated French beans (Phaseolus vulgaris).

    NARCIS (Netherlands)

    Ruth, van S.M.; Roozen, J.P.; Cozijnsen, J.L.

    1996-01-01

    The technique of gas chromatography/sniffing port analysis was evaluated for studying the release of aroma compounds from rehydrated diced French beans. The aroma compounds 2-—methylbutanal and hexanal were released at a constant rate over time. An identical selection of odour active compounds was

  17. Modelling and analysis of offshore energy systems on North Sea oil and gas platforms

    DEFF Research Database (Denmark)

    Nguyen, Tuong-Van; Elmegaard, Brian; Pierobon, Leonardo

    2012-01-01

    export, and power generation. In this paper, a generic model of a North Sea oil and gas platform is described and the most thermodynamically inefficient processes are identified by performing an exergy analysis. Models and simulations are built and run with the tools Aspen Plus R, DNA and Aspen HYSYS R...

  18. Integration of phase change materials in compressed hydrogen gas systems: Modelling and parametric analysis

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Rothuizen, Erasmus; Jørgensen, Jens-Erik

    2016-01-01

    to the phase change material, mainly occurs after the fueling is completed, resulting in a hydrogen peak temperature higher than 85 C and a lower fueled mass than a gas-cooled system. Such a mass reduction accounts for 12% with respect to the case of a standard tank system fueled at 40 C. A parametric analysis...

  19. Some aspects of the analysis of labelled organic compounds by gas radiochromatography

    International Nuclear Information System (INIS)

    Heise, K.H.; Gorner, Ch.; Bubner, M.

    1977-01-01

    The first experience with the analysis of tritium-and 14 C-labelled compounds by gas radiochromatography are reported. The instrumental arrangement is described where, on the chromatograph output, the radioactive compounds are burnt, and the radioactive gases are measured by scintillation detectors in a coincidence circuit

  20. Quantitative analysis of target components by comprehensive two-dimensional gas chromatography

    NARCIS (Netherlands)

    Mispelaar, V.G. van; Tas, A.C.; Smilde, A.K.; Schoenmakers, P.J.; Asten, A.C. van

    2003-01-01

    Quantitative analysis using comprehensive two-dimensional (2D) gas chromatography (GC) is still rarely reported. This is largely due to a lack of suitable software. The objective of the present study is to generate quantitative results from a large GC x GC data set, consisting of 32 chromatograms.

  1. High-resolution gas chromatographic analysis of polycyclic aromatic hydrocarbons and aliphatic hydrocarbons

    International Nuclear Information System (INIS)

    Perez, M.; Gonzalez, D.

    1988-01-01

    A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons and aliphatic hydrocarbons is presented. The separation has been carried out by glass and fused silica capillary column in two different polar stationary phases OV-1 and SE-54. The limitation and the advantages of the procedure are discussed in terms of separation, sensitivity and precision. (Author) 20 refs

  2. Semi-continuous high speed gas analysis of generated vapors of chemical warfare agents

    NARCIS (Netherlands)

    Trap, H.C.; Langenberg, J.P.

    1999-01-01

    A method is presented for the continuous analysis of generated vapors of the nerve agents soman and satin and the blistering agent sulfur mustard. By using a gas sampling valve and a very short (15 cm) column connected to an on-column injector with a 'standard length' column, the system can either

  3. Analysis of Radioactivity Contamination Level of Kartini Reactor Efluen Gas to the Environment

    International Nuclear Information System (INIS)

    Suratman; Purwanto; Aminjoyo, S

    1996-01-01

    The analysis of radioactivity contamination level of Kartini reactor efluen gas to the environment has been done from 13-10-'95 until 8-2-'96. The aim of this research is to determine the radioactivity contamination level on the environment resulted from the release of Kartini reactor efluen gas and other facilities at Yogyakarta Nuclear Research Centre through stack. The analysis methods is the student t-test, the first count factor test and the gamma spectrometry. The gas sampling were carried out in the stack reactor, reactor room, environment and in other room for comparison. Efluen gas was sucked through a filter by a high volume vacuum pump. The filter was counted for beta, gamma and alpha activities. The radioactivity contamination level of the efluen gas passing through the stack to the environment was measured between 0.57 - 1.34 Bq/m3, which was equal to the airborne radioactivity in environment between 0.69 - 1.12 Bq/m3. This radioactivity comes from radon daughter, decay products result from the natural uranium and thorium series of the materials of the building

  4. Parametric Analysis of a Two-Shaft Aeroderivate Gas Turbine of 11.86 MW

    Directory of Open Access Journals (Sweden)

    R. Lugo-Leyte

    2015-08-01

    Full Text Available The aeroderivate gas turbines are widely used for power generation in the oil and gas industry. In offshore marine platforms, the aeroderivative gas turbines provide the energy required to drive mechanically compressors, pumps and electric generators. Therefore, the study of the performance of aeroderivate gas turbines based on a parametric analysis is relevant to carry out a diagnostic of the engine, which can lead to operational as well as predictive and/or corrective maintenance actions. This work presents a methodology based on the exergetic analysis to estimate the irrevesibilities and exergetic efficiencies of the main components of a two-shaft aeroderivate gas turbine. The studied engine is the Solar Turbine Mars 100, which is rated to provide 11.86 MW. In this engine, the air is compressed in an axial compressor achieving a pressure ratio of 17.7 relative to ambient conditions and a high pressure turbine inlet temperature of 1220 °C. Even if the thermal efficiency associated to the pressure ratio of 17.7 is 1% lower than the maximum thermal efficiency, the irreversibilities related to this pressure ratio decrease approximately 1 GW with respect to irreversibilities of the optimal pressure ratio for the thermal efficiency. In addition, this paper contributes to develop a mathematical model to estimate the high turbine inlet temperature as well as the pressure ratio of the low and high pressure turbines.

  5. Towards Breath Gas Analysis Based on Millimeter-Wave Molecular Spectroscopy

    Science.gov (United States)

    Rothbart, Nick; Hübers, Heinz-Wilhelm; Schmalz, Klaus; Borngräber, Johannes; Kissinger, Dietmar

    2018-03-01

    Breath gas analysis is a promising non-invasive tool for medical diagnosis as there are thousands of Volatile Organic Compounds (VOCs) in human breath that can be used as health monitoring markers. Millimeter-wave/terahertz molecular spectroscopy is highly suitable for breath gas analysis due to unique fingerprint spectra of many VOCs in that frequency range. We present our recent work on sensor systems for gas spectroscopy based on integrated transmitters (TX) and receivers (RX) fabricated in IHP's 0.13 μm SiGe BiCMOS technology. For a single-band system, spectroscopic measurements and beam profiles are presented. The frequency is tuned by direct voltage-frequency tuning and by a fractional-n PLL, respectively. The spectroscopic system includes a folded gas absorption cell with gas pre-concentration abilities demonstrating the detection of a 50 ppm mixture of ethanol in ambient air corresponding to a minimum detectable concentration of 260 ppb. Finally, the design of a 3-band system covering frequencies from 225 to 273 GHz is introduced.

  6. The determination of frequency response function of the RSG Gas by laplace transform analysis

    International Nuclear Information System (INIS)

    Tukiran, S.; Surian, P.; Jujuratisbela, U.

    1997-01-01

    The response function of the RSG-GAS reactor system to the reactivity perturbations is necessary to be analyzed due to the interrelation with reliability and safety of reactor operation. the response depends on the power frequency response function H(s), while H(s) depends on the zero power frequency response function Z(s) and dynamic power coefficient of reactivity Kp(s) determination of the frequency response function of the RSG-GAS reactor was done by Fourier transform analysis method. Z(s) was obtained by fourier transform of P(t) and Cj(t) became P(S) and Cj(s) in point kinetic equations. Second order of simpson rule was used for completion of its numerical integration. then. LYMPR (Laplace transform for multipurpose reactor) code was made with fortran 77 computer language in vax 8550 system. the LTMPR code is able to determine the frequency response function and period-reactivity relation of RSG-GAS reactor by rod drop method. Profile of power as rod drop, zero power (without reactivity feedback) was used for determination frequency response of RSG-GAS reactor. The results of calculations are in a good agreement with experiment result, so the LTMPR code can be used for analysis response frequency of the RSG-GAS reactor

  7. Analysis of fission gas release in LWR fuel using the BISON code

    Energy Technology Data Exchange (ETDEWEB)

    G. Pastore; J.D. Hales; S.R. Novascone; D.M. Perez; B.W. Spencer; R.L. Williamson

    2013-09-01

    Recent advances in the development of the finite-element based, multidimensional fuel performance code BISON of Idaho National Laboratory are presented. Specifically, the development, implementation and testing of a new model for the analysis of fission gas behavior in LWR-UO2 fuel during irradiation are summarized. While retaining a physics-based description of the relevant mechanisms, the model is characterized by a level of complexity suitable for application to engineering-scale nuclear fuel analysis and consistent with the uncertainties pertaining to some parameters. The treatment includes the fundamental features of fission gas behavior, among which are gas diffusion and precipitation in fuel grains, growth and coalescence of gas bubbles at grain faces, grain growth and grain boundary sweeping effects, thermal, athermal, and transient gas release. The BISON code incorporating the new model is applied to the simulation of irradiation experiments from the OECD/NEA International Fuel Performance Experiments database, also included in the IAEA coordinated research projects FUMEX-II and FUMEX-III. The comparison of the results with the available experimental data at moderate burn-up is presented, pointing out an encouraging predictive accuracy, without any fitting applied to the model parameters.

  8. Techno-economic analysis for the evaluation of three UCG synthesis gas end use approaches

    Science.gov (United States)

    Nakaten, Natalie; Kempka, Thomas; Burchart-Korol, Dorota; Krawczyk, Piotr; Kapusta, Krzysztof; Stańczyk, Krzysztof

    2016-04-01

    Underground coal gasification (UCG) enables the utilization of coal reserves that are economically not exploitable because of complex geological boundary conditions. In the present study we investigate UCG as a potential economic approach for conversion of deep-seated coals into a synthesis gas and its application within three different utilization options. Related to geological boundary conditions and the chosen gasification agent, UCG synthesis gas composes of varying methane, hydrogen, nitrogen, carbon monoxide and carbon dioxide amounts. In accordance to its calorific value, the processed UCG synthesis gas can be utilized in different manners, as for electricity generation in a combined cycle power plant or for feedstock production making use of its various chemical components. In the present study we analyze UCG synthesis gas utilization economics in the context of clean electricity generation with an integrated carbon capture and storage process (CCS) as well as synthetic fuel and fertilizer production (Kempka et al., 2010) based on a gas composition achieved during an in situ UCG trial in the Wieczorek Mine. Hereby, we also consider chemical feedstock production in order to mitigate CO2 emissions. Within a sensitivity analysis of UCG synthesis gas calorific value variations, we produce a range of capital and operational expenditure bandwidths that allow for an economic assessment of different synthesis gas end use approaches. To carry out the integrated techno-economic assessment of the coupled systems and the sensitivity analysis, we adapted the techno-economic UCG-CCS model developed by Nakaten et al. (2014). Our techno-economic modeling results demonstrate that the calorific value has a high impact on the economics of UCG synthesis gas utilization. In the underlying study, the synthesis gas is not suitable for an economic competitive electricity generation, due to the relatively low calorific value of 4.5 MJ/Nm³. To be a profitable option for electricity

  9. Application of modern online instrumentation for chemical analysis of gas and particulate phases of exhaust at the European Commission heavy-duty vehicle emission laboratory.

    Science.gov (United States)

    Adam, T W; Chirico, R; Clairotte, M; Elsasser, M; Manfredi, U; Martini, G; Sklorz, M; Streibel, T; Heringa, M F; Decarlo, P F; Baltensperger, U; De Santi, G; Krasenbrink, A; Zimmermann, R; Prevot, A S H; Astorga, C

    2011-01-01

    The European Commission recently established a novel test facility for heavy-duty vehicles to enhance more sustainable transport. The facility enables the study of energy efficiency of various fuels/scenarios as well as the chemical composition of evolved exhaust emissions. Sophisticated instrumentation for real-time analysis of the gas and particulate phases of exhaust has been implemented. Thereby, gas-phase characterization was carried out by a Fourier transform infrared spectrometer (FT-IR; carbonyls, nitrogen-containing species, small hydrocarbons) and a resonance-enhanced multiphoton ionization time-of-flight mass spectrometer (REMPI-TOFMS; monocyclic and polycyclic aromatic hydrocarbons). For analysis of the particulate phase, a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS; organic matter, chloride, nitrate), a condensation particle counter (CPC; particle number), and a multiangle absorption photometer (MAAP; black carbon) were applied. In this paper, the first application of the new facility in combination with the described instruments is presented, whereby a medium-size truck was investigated by applying different driving cycles. The goal was simultaneous chemical characterization of a great variety of gaseous compounds and particulate matter in exhaust on a real-time basis. The time-resolved data allowed new approaches to view the results; for example, emission factors were normalized to time-resolved consumption of fuel and were related to emission factors evolved during high speeds. Compounds could be identified that followed the fuel consumption, others showed very different behavior. In particular, engine cold start, engine ignition (unburned fuel), and high-speed events resulted in unique emission patterns.

  10. Comparative analysis of monetizing technologies for the use of offshore natural gas; Analise comparativa das tecnologias embarcadas de aproveitamento de gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Biruel Junior, Jose

    2008-09-15

    The growing world need for natural gas, the issue of offshore oil and associated gas exploration in regions constantly farther from the consumer market, and the law restrictions due to greenhouses gases emissions have stimulated the development of technologies intended to monetizing stranded gas reserves. In order to compare these technologies, a Multi Criteria Decision Analysis Methodology, based on fuzzy parameters, has been developed. The Methodology enables specialists to define analysis dimensions and criteria as well as to assign weight and ratings by means of linguistic variables, resulting in a general performance index for each technology. The Methodology has been applied in a case study to compare the floating technologies FCNG (Floating Compressed Natural Gas), FLNG (Floating Liquefied Natural Gas), FGTL (Floating Gas-to-Liquid) and FGTW (Floating Gas-to- Wire). The efficacy of the Methodology depends on the comprehensiveness and quality of the information provided. Therefore, this dissertation presents a study of these technologies, placing strong emphasis on the Technological Dimension. The Methodology allows for the identification of the drawbacks of each technology so as to especially conduct R and D efforts to improve their competitiveness. (author)

  11. Evolving artificial metalloenzymes via random mutagenesis

    Science.gov (United States)

    Yang, Hao; Swartz, Alan M.; Park, Hyun June; Srivastava, Poonam; Ellis-Guardiola, Ken; Upp, David M.; Lee, Gihoon; Belsare, Ketaki; Gu, Yifan; Zhang, Chen; Moellering, Raymond E.; Lewis, Jared C.

    2018-03-01

    Random mutagenesis has the potential to optimize the efficiency and selectivity of protein catalysts without requiring detailed knowledge of protein structure; however, introducing synthetic metal cofactors complicates the expression and screening of enzyme libraries, and activity arising from free cofactor must be eliminated. Here we report an efficient platform to create and screen libraries of artificial metalloenzymes (ArMs) via random mutagenesis, which we use to evolve highly selective dirhodium cyclopropanases. Error-prone PCR and combinatorial codon mutagenesis enabled multiplexed analysis of random mutations, including at sites distal to the putative ArM active site that are difficult to identify using targeted mutagenesis approaches. Variants that exhibited significantly improved selectivity for each of the cyclopropane product enantiomers were identified, and higher activity than previously reported ArM cyclopropanases obtained via targeted mutagenesis was also observed. This improved selectivity carried over to other dirhodium-catalysed transformations, including N-H, S-H and Si-H insertion, demonstrating that ArMs evolved for one reaction can serve as starting points to evolve catalysts for others.

  12. Parallel Hybrid Gas-Electric Geared Turbofan Engine Conceptual Design and Benefits Analysis

    Science.gov (United States)

    Lents, Charles; Hardin, Larry; Rheaume, Jonathan; Kohlman, Lee

    2016-01-01

    The conceptual design of a parallel gas-electric hybrid propulsion system for a conventional single aisle twin engine tube and wing vehicle has been developed. The study baseline vehicle and engine technology are discussed, followed by results of the hybrid propulsion system sizing and performance analysis. The weights analysis for the electric energy storage & conversion system and thermal management system is described. Finally, the potential system benefits are assessed.

  13. A Graphical Adversarial Risk Analysis Model for Oil and Gas Drilling Cybersecurity

    OpenAIRE

    Vieira, Aitor Couce; Houmb, Siv Hilde; Insua, David Rios

    2014-01-01

    Oil and gas drilling is based, increasingly, on operational technology, whose cybersecurity is complicated by several challenges. We propose a graphical model for cybersecurity risk assessment based on Adversarial Risk Analysis to face those challenges. We also provide an example of the model in the context of an offshore drilling rig. The proposed model provides a more formal and comprehensive analysis of risks, still using the standard business language based on decisions, risks, and value.

  14. A Graphical Adversarial Risk Analysis Model for Oil and Gas Drilling Cybersecurity

    Directory of Open Access Journals (Sweden)

    Aitor Couce Vieira

    2014-04-01

    Full Text Available Oil and gas drilling is based, increasingly, on operational technology, whose cybersecurity is complicated by several challenges. We propose a graphical model for cybersecurity risk assessment based on Adversarial Risk Analysis to face those challenges. We also provide an example of the model in the context of an offshore drilling rig. The proposed model provides a more formal and comprehensive analysis of risks, still using the standard business language based on decisions, risks, and value.

  15. Evolving phenotypic networks in silico.

    Science.gov (United States)

    François, Paul

    2014-11-01

    Evolved gene networks are constrained by natural selection. Their structures and functions are consequently far from being random, as exemplified by the multiple instances of parallel/convergent evolution. One can thus ask if features of actual gene networks can be recovered from evolutionary first principles. I review a method for in silico evolution of small models of gene networks aiming at performing predefined biological functions. I summarize the current implementation of the algorithm, insisting on the construction of a proper "fitness" function. I illustrate the approach on three examples: biochemical adaptation, ligand discrimination and vertebrate segmentation (somitogenesis). While the structure of the evolved networks is variable, dynamics of our evolved networks are usually constrained and present many similar features to actual gene networks, including properties that were not explicitly selected for. In silico evolution can thus be used to predict biological behaviours without a detailed knowledge of the mapping between genotype and phenotype. Copyright © 2014 The Author. Published by Elsevier Ltd.. All rights reserved.

  16. Ranking in evolving complex networks

    Science.gov (United States)

    Liao, Hao; Mariani, Manuel Sebastian; Medo, Matúš; Zhang, Yi-Cheng; Zhou, Ming-Yang

    2017-05-01

    Complex networks have emerged as a simple yet powerful framework to represent and analyze a wide range of complex systems. The problem of ranking the nodes and the edges in complex networks is critical for a broad range of real-world problems because it affects how we access online information and products, how success and talent are evaluated in human activities, and how scarce resources are allocated by companies and policymakers, among others. This calls for a deep understanding of how existing ranking algorithms perform, and which are their possible biases that may impair their effectiveness. Many popular ranking algorithms (such as Google's PageRank) are static in nature and, as a consequence, they exhibit important shortcomings when applied to real networks that rapidly evolve in time. At the same time, recent advances in the understanding and modeling of evolving networks have enabled the development of a wide and diverse range of ranking algorithms that take the temporal dimension into account. The aim of this review is to survey the existing ranking algorithms, both static and time-aware, and their applications to evolving networks. We emphasize both the impact of network evolution on well-established static algorithms and the benefits from including the temporal dimension for tasks such as prediction of network traffic, prediction of future links, and identification of significant nodes.

  17. Decomposition analysis of gas consumption in the residential sector in Ireland

    International Nuclear Information System (INIS)

    Rogan, Fionn; Cahill, Caiman J.; Ó Gallachóir, Brian P.

    2012-01-01

    To-date, decomposition analysis has been widely used at the macro-economic level and for in-depth analyses of the industry and transport sectors; however, its application in the residential sector has been rare. This paper uses the Log-Mean Divisia Index I (LMDI-I) methodology to decompose gas consumption trends in the gas-connected residential sector in Ireland from 1990 to 2008, which despite an increasing number of energy efficiency policies, experienced total final consumption growth of 470%. The analysis decomposes this change in gas consumption into a number of effects, examining the impact over time of market factors such as a growing customer base, varying mix of dwelling types, changing share of vacant dwellings, changing size of new dwellings, the impact of building regulations policy and other factors such as the weather. The analysis finds the most significant effects are changing customer numbers and changing intensity; the analysis also quantifies the impact of building regulations and compares it with other effects such as changing size of new dwellings. By comparing the historical impact on gas consumption of policy factors and non-policy factors, this paper highlights the challenge for policy-makers in achieving overall energy consumption reduction. - Highlights: ► Contribution to a gap in the literature with a residential sector decomposition analysis of gas TFC. ► Activity effect had the largest impact and was cumulatively the best explainer of total TFC change. ► Intensity effect was the second biggest effect with a 19% share of total TFC change. ► In line with rising surface temperatures, the weather effect is declining over time. ► Building regulations are having a diminishing impact but are being negated by larger dwellings.

  18. The EU Legislative Framework Against Money Laundering and Terrorist Finance:A Critical Analysis in the Light of Evolving Global Standards

    OpenAIRE

    Gilmore, William; Mitsilegas, Valsamis

    2007-01-01

    This article examines the evolution of the EU anti-money laundering legislative framework (which in recent years has also included measures to counter terrorist finance), by focusing in particular on recent legislation such as the third money laundering Directive and the Regulation on controls of cash entering the EU, both adopted in 2005. The analysis highlights the relationship between these instruments and international initiatives in the field (in particular FATF standards), and addresses...

  19. CHEMICAL ANALYSIS OF DENSE-GAS EXTRACTS FROM LIME FLOWERS

    Directory of Open Access Journals (Sweden)

    Demyanenko DV

    2015-04-01

    Full Text Available The purpose of this work was to make qualitative and quantitative analysis of phenolic biologically active substances (BAS in the extracts produced from lime flowers with condensed gases, using method of high-performance liquid chromatography (HPLC. Materials and methods: materials for this study were the extracts obtained by consequent processing of the herbal drug and marcs thereof with various condensed gases: difluorochloromethane (Freon R22, difluoromethane (Freon R32, azeotropic mixture of difluoromethane with pentafluoroethane (Freon 410A and freon-ammonium mixture. Extracts obtained with the latter were subjected to further fractionation by liquidliquid separation into hexane, chloroform, ethyl acetate and aqueous-alcohol phases. Besides, the supercritical СО2 extract, obtained from the herbal drug under rather strong conditions (at temperature 60°С and pressure 400 bar, was studied in our previous research. Presence of phenolic BAS and their quantity in the researched samples were determined by method of HPLC with UVspectrometric detection. Results and discussion: It has been found that Freon R22 extracted trace amounts of rutin from lime flowers – its content was only 0.08% of the total extract weight. On the other hand, Freons R32 and R410А showed good selectivity to moderately polar BAS of lime flowers (derivatives of flavonoids and hydroxycinnamic acids: in particular, the extract obtained with freon R32 contained about 1.3% of the total phenolic substances, and it was the only one of the investigated condensed gases used by us which took the basic flavonoid of lime flowers tiliroside – its content was 0.42% of extract weight. Also Freons R32 and R410А were able to withdraw another compound dominating among phenolic substances in the yielded extracts. Its quantity was rather noticeable – up to 0.87% of extract weight. This substance was not identified by existing database, but its UV-spectrum was similar to those of

  20. Comparative Analysis of Volatile Defensive Secretions of Three Species of Pyrrhocoridae (Insecta: Heteroptera by Gas Chromatography-Mass Spectrometric Method.

    Directory of Open Access Journals (Sweden)

    Jan Krajicek

    Full Text Available The true bugs (Hemiptera: Heteroptera have evolved a system of well-developed scent glands that produce diverse and frequently strongly odorous compounds that act mainly as chemical protection against predators. A new method of non-lethal sampling with subsequent separation using gas chromatography with mass spectrometric detection was proposed for analysis of these volatile defensive secretions. Separation was performed on Rtx-200 column containing fluorinated polysiloxane stationary phase. Various mechanical irritation methods (ultrasonics, shaking, pressing bugs with plunger of syringe were tested for secretion sampling with a special focus on non-lethal irritation. The preconcentration step was performed by sorption on solid phase microextraction (SPME fibers with different polarity. For optimization of sampling procedure, Pyrrhocoris apterus was selected. The entire multi-parameter optimization procedure of secretion sampling was performed using response surface methodology. The irritation of bugs by pressing them with a plunger of syringe was shown to be the most suitable. The developed method was applied to analysis of secretions produced by adult males and females of Pyrrhocoris apterus, Pyrrhocoris tibialis and Scantius aegyptius (all Heteroptera: Pyrrhocoridae. The chemical composition of secretion, particularly that of alcohols, aldehydes and esters, is species-specific in all three pyrrhocorid species studied. The sexual dimorphism in occurrence of particular compounds is largely limited to alcohols and suggests their epigamic intraspecific function. The phenetic overall similarities in composition of secretion do not reflect either relationship of species or similarities in antipredatory color pattern. The similarities of secretions may be linked with antipredatory strategies. The proposed method requires only a few individuals which remain alive after the procedure. Thus secretions of a number of species including even the rare

  1. Risk Analysis on Leakage Failure of Natural Gas Pipelines by Fuzzy Bayesian Network with a Bow-Tie Model

    OpenAIRE

    Shan, Xian; Liu, Kang; Sun, Pei-Liang

    2017-01-01

    Pipeline is the major mode of natural gas transportation. Leakage of natural gas pipelines may cause explosions and fires, resulting in casualties, environmental damage, and material loss. Efficient risk analysis is of great significance for preventing and mitigating such potential accidents. The objective of this study is to present a practical risk assessment method based on Bow-tie model and Bayesian network for risk analysis of natural gas pipeline leakage. Firstly, identify the potential...

  2. Dynamic analysis of natural gas distribution sector in Bahia: case study of the Gas State Company entry

    International Nuclear Information System (INIS)

    Ribeiro, H.M.

    1988-01-01

    For the Natural Gas Distribution Sector in Bahia, some preliminary scenarios and theoretical concerns are presented under the perspectives of the Gas State Company entry. These scenarios are derived from the going institutional changes and physical expansion of the Sector with the increasing natural gas usage. The study has the objective of anticipating, for the State Government and its partners in the Company, the strategies and relevant problems for a successful entrance into this Sector. (author)

  3. canEvolve: a web portal for integrative oncogenomics.

    Directory of Open Access Journals (Sweden)

    Mehmet Kemal Samur

    Full Text Available BACKGROUND & OBJECTIVE: Genome-wide profiles of tumors obtained using functional genomics platforms are being deposited to the public repositories at an astronomical scale, as a result of focused efforts by individual laboratories and large projects such as the Cancer Genome Atlas (TCGA and the International Cancer Genome Consortium. Consequently, there is an urgent need for reliable tools that integrate and interpret these data in light of current knowledge and disseminate results to biomedical researchers in a user-friendly manner. We have built the canEvolve web portal to meet this need. RESULTS: canEvolve query functionalities are designed to fulfill most frequent analysis needs of cancer researchers with a view to generate novel hypotheses. canEvolve stores gene, microRNA (miRNA and protein expression profiles, copy number alterations for multiple cancer types, and protein-protein interaction information. canEvolve allows querying of results of primary analysis, integrative analysis and network analysis of oncogenomics data. The querying for primary analysis includes differential gene and miRNA expression as well as changes in gene copy number measured with SNP microarrays. canEvolve provides results of integrative analysis of gene expression profiles with copy number alterations and with miRNA profiles as well as generalized integrative analysis using gene set enrichment analysis. The network analysis capability includes storage and visualization of gene co-expression, inferred gene regulatory networks and protein-protein interaction information. Finally, canEvolve provides correlations between gene expression and clinical outcomes in terms of univariate survival analysis. CONCLUSION: At present canEvolve provides different types of information extracted from 90 cancer genomics studies comprising of more than 10,000 patients. The presence of multiple data types, novel integrative analysis for identifying regulators of oncogenesis, network

  4. Life Cycle Greenhouse Gas Analysis of Multiple Vehicle Fuel Pathways in China

    Directory of Open Access Journals (Sweden)

    Tianduo Peng

    2017-11-01

    Full Text Available The Tsinghua University Life Cycle Analysis Model (TLCAM is applied to calculate the life cycle fossil energy consumption and greenhouse gas (GHG emissions for more than 20 vehicle fuel pathways in China. In addition to conventional gasoline and diesel, these include coal- and gas-based vehicle fuels, and electric vehicle (EV pathways. The results indicate the following. (1 China’s current dependence on coal and relative low-efficiency processes limits the potential for most alternative fuel pathways to decrease energy consumption and emissions; (2 Future low-carbon electricity pathways offer more obvious advantages, with coal-based pathways needing to adopt carbon dioxide capture and storage technology to compete; (3 A well-to-wheels analysis of the fossil energy consumption of vehicles fueled by compressed natural gas and liquefied natural gas (LNG showed that they are comparable to conventional gasoline vehicles. However, importing rather than domestically producing LNG for vehicle use can decrease domestic GHG emissions by 35% and 31% compared with those of conventional gasoline and diesel vehicles, respectively; (4 The manufacturing and recovery of battery and vehicle in the EV analysis has significant impact on the overall ability of EVs to decrease fossil energy consumption and GHG emissions from ICEVs.

  5. Development Optimization and Uncertainty Analysis Methods for Oil and Gas Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Ettehadtavakkol, Amin, E-mail: amin.ettehadtavakkol@ttu.edu [Texas Tech University (United States); Jablonowski, Christopher [Shell Exploration and Production Company (United States); Lake, Larry [University of Texas at Austin (United States)

    2017-04-15

    Uncertainty complicates the development optimization of oil and gas exploration and production projects, but methods have been devised to analyze uncertainty and its impact on optimal decision-making. This paper compares two methods for development optimization and uncertainty analysis: Monte Carlo (MC) simulation and stochastic programming. Two example problems for a gas field development and an oilfield development are solved and discussed to elaborate the advantages and disadvantages of each method. Development optimization involves decisions regarding the configuration of initial capital investment and subsequent operational decisions. Uncertainty analysis involves the quantification of the impact of uncertain parameters on the optimum design concept. The gas field development problem is designed to highlight the differences in the implementation of the two methods and to show that both methods yield the exact same optimum design. The results show that both MC optimization and stochastic programming provide unique benefits, and that the choice of method depends on the goal of the analysis. While the MC method generates more useful information, along with the optimum design configuration, the stochastic programming method is more computationally efficient in determining the optimal solution. Reservoirs comprise multiple compartments and layers with multiphase flow of oil, water, and gas. We present a workflow for development optimization under uncertainty for these reservoirs, and solve an example on the design optimization of a multicompartment, multilayer oilfield development.

  6. Development of a new method for hydrogen isotope analysis of trace hydrocarbons in natural gas samples

    Directory of Open Access Journals (Sweden)

    Xibin Wang

    2016-12-01

    Full Text Available A new method had been developed for the analysis of hydrogen isotopic composition of trace hydrocarbons in natural gas samples by using solid phase microextraction (SPME combined with gas chromatography-isotope ratio mass spectrometry (GC/IRMS. In this study, the SPME technique had been initially introduced to achieve the enrichment of trace content of hydrocarbons with low abundance and coupled to GC/IRMS for hydrogen isotopic analysis. The main parameters, including the equilibration time, extraction temperature, and the fiber type, were systematically optimized. The results not only demonstrated that high extraction yield was true but also shows that the hydrogen isotopic fractionation was not observed during the extraction process, when the SPME device fitted with polydimethylsiloxane/divinylbenzene/carbon molecular sieve (PDMS/DVB/CAR fiber. The applications of SPME-GC/IRMS method were evaluated by using natural gas samples collected from different sedimentary basins; the standard deviation (SD was better than 4‰ for reproducible measurements; and also, the hydrogen isotope values from C1 to C9 can be obtained with satisfying repeatability. The SPME-GC/IRMS method fitted with PDMS/DVB/CAR fiber is well suited for the preconcentration of trace hydrocarbons, and provides a reliable hydrogen isotopic analysis for trace hydrocarbons in natural gas samples.

  7. Development Optimization and Uncertainty Analysis Methods for Oil and Gas Reservoirs

    International Nuclear Information System (INIS)

    Ettehadtavakkol, Amin; Jablonowski, Christopher; Lake, Larry

    2017-01-01

    Uncertainty complicates the development optimization of oil and gas exploration and production projects, but methods have been devised to analyze uncertainty and its impact on optimal decision-making. This paper compares two methods for development optimization and uncertainty analysis: Monte Carlo (MC) simulation and stochastic programming. Two example problems for a gas field development and an oilfield development are solved and discussed to elaborate the advantages and disadvantages of each method. Development optimization involves decisions regarding the configuration of initial capital investment and subsequent operational decisions. Uncertainty analysis involves the quantification of the impact of uncertain parameters on the optimum design concept. The gas field development problem is designed to highlight the differences in the implementation of the two methods and to show that both methods yield the exact same optimum design. The results show that both MC optimization and stochastic programming provide unique benefits, and that the choice of method depends on the goal of the analysis. While the MC method generates more useful information, along with the optimum design configuration, the stochastic programming method is more computationally efficient in determining the optimal solution. Reservoirs comprise multiple compartments and layers with multiphase flow of oil, water, and gas. We present a workflow for development optimization under uncertainty for these reservoirs, and solve an example on the design optimization of a multicompartment, multilayer oilfield development.

  8. 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.

  9. Doping control analysis of anabolic steroids in equine urine by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wong, April S Y; Leung, Gary N W; Leung, David K K; Wan, Terence S M

    2017-09-01

    Anabolic steroids are banned substances in equine sports. Gas chromatography-mass spectrometry (GC-MS) has been the traditional technique for doping control analysis of anabolic steroids in biological samples. Although liquid chromatography-mass spectrometry (LC/MS) has become an important technique in doping control, the detection of saturated hydroxysteroids by LC-MS remains a problem due to their low ionization efficiency under electrospray. The recent development in fast-scanning gas-chromatography-triple-quadrupole mass spectrometry (GC-MS/MS) has provided a better alternative with a significant reduction in chemical noise by means of selective reaction monitoring. Herein, we present a sensitive and selective method for the screening of over 50 anabolic steroids in equine urine using gas chromatography-tandem mass spectrometry (GC-MS/MS). Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  10. Shock Structure Analysis and Aerodynamics in a Weakly Ionized Gas Flow

    Science.gov (United States)

    Saeks, R.; Popovic, S.; Chow, A. S.

    2006-01-01

    The structure of a shock wave propagating through a weakly ionized gas is analyzed using an electrofluid dynamics model composed of classical conservation laws and Gauss Law. A viscosity model is included to correctly model the spatial scale of the shock structure, and quasi-neutrality is not assumed. A detailed analysis of the structure of a shock wave propagating in a weakly ionized gas is presented, together with a discussion of the physics underlying the key features of the shock structure. A model for the flow behind a shock wave propagating through a weakly ionized gas is developed and used to analyze the effect of the ionization on the aerodynamics and performance of a two-dimensional hypersonic lifting body.

  11. Thermal Stress FE Analysis of Large-scale Gas Holder Under Sunshine Temperature Field

    Science.gov (United States)

    Li, Jingyu; Yang, Ranxia; Wang, Hehui

    2018-03-01

    The temperature field and thermal stress of Man type gas holder is simulated by using the theory of sunshine temperature field based on ASHRAE clear-sky model and the finite element method. The distribution of surface temperature and thermal stress of gas holder under the given sunshine condition is obtained. The results show that the thermal stress caused by sunshine can be identified as one of the important factors for the failure of local cracked oil leakage which happens on the sunny side before on the shady side. Therefore, it is of great importance to consider the sunshine thermal load in the stress analysis, design and operation of large-scale steel structures such as the gas holder.

  12. Preliminary analysis of combined cycle of modular high-temperature gas cooled reactor

    International Nuclear Information System (INIS)

    Baogang, Z.; Xiaoyong, Y.; Jie, W.; Gang, Z.; Qian, S.

    2015-01-01

    Modular high-temperature gas cooled reactor (HTGR) is known as one of the most advanced nuclear reactors because of its inherent safety and high efficiency. The power conversion system of HTGR can be steam turbine based on Rankine cycle or gas turbine based on Brayton cycle respectively. The steam turbine system is mature and the gas turbine system has high efficiency but under development. The Brayton-Rankine combined cycle is an effective way to further promote the efficiency. This paper investigated the performance of combined cycle from the viewpoint of thermodynamics. The effect of non-dimensional parameters on combined cycle’s efficiency, such as temperature ratio, compression ratio, efficiency of compressor, efficiency of turbine, was analyzed. Furthermore, the optimal parameters to achieve highest efficiency was also given by this analysis under engineering constraints. The conclusions could be helpful to the design and development of combined cycle of HTGR. (author)

  13. Bifurcation and nonlinear dynamic analysis of a flexible rotor supported by relative short gas journal bearings

    International Nuclear Information System (INIS)

    Wang, C.-C.; Jang, M.-J.; Yeh, Y.-L.

    2007-01-01

    This paper studies the bifurcation and nonlinear behaviors of a flexible rotor supported by relative short gas film bearings. A time-dependent mathematical model for gas journal bearings is presented. The finite difference method with successive over relation method is employed to solve the Reynolds' equation. The system state trajectory, Poincare maps, power spectra, and bifurcation diagrams are used to analyze the dynamic behavior of the rotor and journal center in the horizontal and vertical directions under different operating conditions. The analysis reveals a complex dynamic behavior comprising periodic and subharmonic response of the rotor and journal center. This paper shows how the dynamic behavior of this type of system varies with changes in rotor mass and rotational velocity. The results of this study contribute to a further understanding of the nonlinear dynamics of gas film rotor-bearing systems

  14. Analysis of Critical Permeabilty, Capillary Pressure and Electrical Properties for Mesaverde Tight Gas Sandstones from Western U.S. Basins

    Energy Technology Data Exchange (ETDEWEB)

    Alan Byrnes; Robert Cluff; John Webb; John Victorine; Ken Stalder; Daniel Osburn; Andrew Knoderer; Owen Metheny; Troy Hommertzheim; Joshua Byrnes; Daniel Krygowski; Stefani Whittaker

    2008-06-30

    Although prediction of future natural gas supply is complicated by uncertainty in such variables as demand, liquefied natural gas supply price and availability, coalbed methane and gas shale development rate, and pipeline availability, all U.S. Energy Information Administration gas supply estimates to date have predicted that Unconventional gas sources will be the dominant source of U.S. natural gas supply for at least the next two decades (Fig. 1.1; the period of estimation). Among the Unconventional gas supply sources, Tight Gas Sandstones (TGS) will represent 50-70% of the Unconventional gas supply in this time period (Fig. 1.2). Rocky Mountain TGS are estimated to be approximately 70% of the total TGS resource base (USEIA, 2005) and the Mesaverde Group (Mesaverde) sandstones represent the principal gas productive sandstone unit in the largest Western U.S. TGS basins including the basins that are the focus of this study (Washakie, Uinta, Piceance, northern Greater Green River, Wind River, Powder River). Industry assessment of the regional gas resource, projection of future gas supply, and exploration programs require an understanding of reservoir properties and accurate tools for formation evaluation. The goal of this study is to provide petrophysical formation evaluation tools related to relative permeability, capillary pressure, electrical properties and algorithms for wireline log analysis. Detailed and accurate moveable gas-in-place resource assessment is most critical in marginal gas plays and there is need for quantitative tools for definition of limits on gas producibility due to technology and rock physics and for defining water saturation. The results of this study address fundamental questions concerning: (1) gas storage; (2) gas flow; (3) capillary pressure; (4) electrical properties; (5) facies and upscaling issues; (6) wireline log interpretation algorithms; and (7) providing a web-accessible database of advanced rock properties. The following text

  15. High-Temperature Structural Analysis Model of the Process Heat Exchanger for Helium Gas Loop (II)

    International Nuclear Information System (INIS)

    Song, Kee Nam; Lee, Heong Yeon; Kim, Chan Soo; Hong, Seong Duk; Park, Hong Yoon

    2010-01-01

    PHE (Process Heat Exchanger) is a key component required to transfer heat energy of 950 .deg. C generated in a VHTR (Very High Temperature Reactor) to the chemical reaction that yields a large quantity of hydrogen. Korea Atomic Energy Research Institute established the helium gas loop for the performance test of components, which are used in the VHTR, and they manufactured a PHE prototype to be tested in the loop. In this study, as part of the high temperature structural-integrity evaluation of the PHE prototype, which is scheduled to be tested in the helium gas loop, we carried out high-temperature structural-analysis modeling, thermal analysis, and thermal expansion analysis of the PHE prototype. The results obtained in this study will be used to design the performance test setup for the PHE prototype

  16. Chemically modified glasses for analysis of hydrogen isotopes by gas-chromatography

    International Nuclear Information System (INIS)

    Stanciu, Vasile; Stefanescu, Doina

    1999-01-01

    Hydrogen isotope separation process by such methods as cryogenic distillation or thermal diffusion method is one of the key technologies of the tritium separation from heavy water of CANDU reactors and in the tritium fuel cycle for a thermonuclear fusion reactor. In each process, the analytical techniques for measuring contents of hydrogen isotope mixture are necessary. An extensive experimental research has been carried out in order to produce the most suitable absorbent and define the best operating conditions for selective separation and analysis of hydrogen isotope by gas-chromatography. This paper describes the preparation of adsorbent materials utilised as stationary phase in the gas-chromatographic column for hydrogen isotope separation and treatment (activation) of stationary phase. Modified thermo-resisting glass with Fe(NH 4 ) 2 (SO 4 ) 2 6H 2 O and Cr 2 O 3 , respectively, have been experimentally investigated at 77 K for H 2 , HD and D 2 separation and the results of chromatographic runs are also reported and discussed. The gas-chromatographic apparatus used is composed of a Hewlett-Packard 7620A gas-chromatograph equipped with a gas carrier flow rate controller and a thermal conductivity detector (TCD). The apparatus comprises also a Dewar vessel containing the separation column. The hydrogen isotopes H 2 , HD, D 2 and their mixture have been obtained in our laboratories. The best operating conditions of the adsorbent column Fe (III)/glass and Cr 2 O 3 /glass, i.e. granulometry, column length, pressure-drop along the column, carrier gas flow rate, sample volume have been studied by means of the analysis of the retention times, separation factors and HETP. (authors)

  17. Metal/glass composites for analysis of hydrogen isotopes by gas-chromatography

    International Nuclear Information System (INIS)

    Nicolae, Constantin Adrian; Sisu, Claudia; Stefanescu, Doina; Stanciu, Vasile

    1999-01-01

    The separation process of hydrogen isotopes by cryogenic distillation or thermal diffusion is a key technology for tritium separation from heavy water in CANDU reactor and for tritium fuel cycle in thermonuclear fusion reactor. In each process, analytical techniques for analyzing the hydrogen isotope mixture are required. An extensive experimental research has been carried out in order to produce the most suitable adsorbents and to establish the best operating conditions for selective separation and analysis of hydrogen isotopes by gas-chromatography. This paper describes the preparation of adsorbent materials used as stationary phases in the gas-chromatographic column for hydrogen isotope separation and the treatment (activation) of stationary phases. Modified thermoresisting glass with Fe(NH 4 ) 2 (SO 4 ) 2 ·6H 2 O and Cr 2 O 3 respectively have been experimentally investigated at 77 K for H 2 , HD and D 2 separation and the results of chromatographic runs are reported and discussed. The gas-chromatographic apparatus used in this study is composed of a Hewlett-Packard 7620A gas-chromatograph equipped with a gas carrier flow rate controller and a thermal conductivity detector. The apparatus comprises also a Dewar vessel containing the separation column. The hydrogen isotopes, H 2 , HD, D 2 , and their mixture have been obtained in our laboratories. The best operating conditions and parameters of the Fe 3+ /glass adsorbent column , i.e. granulometry, column length, pressure-drop along the column, carrier gas flow rate and sample volume have been studied by means of the analysis of the retention times, separation factors and HETP. (authors)

  18. Risk analysis of urban gas pipeline network based on improved bow-tie model

    Science.gov (United States)

    Hao, M. J.; You, Q. J.; Yue, Z.

    2017-11-01

    Gas pipeline network is a major hazard source in urban areas. In the event of an accident, there could be grave consequences. In order to understand more clearly the causes and consequences of gas pipeline network accidents, and to develop prevention and mitigation measures, the author puts forward the application of improved bow-tie model to analyze risks of urban gas pipeline network. The improved bow-tie model analyzes accident causes from four aspects: human, materials, environment and management; it also analyzes the consequences from four aspects: casualty, property loss, environment and society. Then it quantifies the causes and consequences. Risk identification, risk analysis, risk assessment, risk control, and risk management will be clearly shown in the model figures. Then it can suggest prevention and mitigation measures accordingly to help reduce accident rate of gas pipeline network. The results show that the whole process of an accident can be visually investigated using the bow-tie model. It can also provide reasons for and predict consequences of an unfortunate event. It is of great significance in order to analyze leakage failure of gas pipeline network.

  19. Gas Bubbles Investigation in Contaminated Water Using Optical Tomography Based on Independent Component Analysis Method

    Directory of Open Access Journals (Sweden)

    Mohd Taufiq Mohd Khairi

    2016-01-01

    Full Text Available This paper presents the results of concentration profiles for gas bubble flow in a vertical pipeline containing contaminated water using an optical tomography system. The concentration profiles for the bubble flow quantities are investigated under five different flows conditions, a single bubble, double bubbles, 25% of air opening, 50% of air opening, and 100% of air opening flow rates where a valve is used to control the gas flow in the vertical pipeline. The system is aided by the independent component analysis (ICA algorithm to reconstruct the concentration profiles of the liquid-gas flow. The behaviour of the gas bubbles was investigated in contaminated water in which the water sample was prepared by adding 25 mL of colour ingredients to 3 liters of pure water. The result shows that the application of ICA has enabled the system to detect the presence of gas bubbles in contaminated water. This information provides vital information on the flow inside the pipe and hence could be very significant in increasing the efficiency of the process industries.

  20. Online gas analysis and diagnosis for RPC detectors in the ATLAS experiment

    International Nuclear Information System (INIS)

    De Asmundis, Riccardo

    2007-01-01

    Resistive Plate Counters (RPC) detectors need a very strict control of gas parameters: motivations for this statement come from both the request of stability in the detector working point, and chemical consideration concerning potentially aggressive materials generated during the ionization processes into the sensitive gap; the latter point can be relevant because of a possible damage to the internal surface of the detector that has to be avoided in order to ensure an high detection efficiency of the RPC during their ten years or more of operation in ATLAS. In order to understand these aspects, detailed studies on gas behavior have been carried on at the GIF-X5 at CERN (2002-2005), based on Gas Chromatographic and spectroscopy techniques. Main results of these analysis are presented here, together with the design of the online analyzer to be installed on ATLAS conceived to keep control of gas quality and to trigger maintenance interventions on the gas system, in particular on the purification subsystem

  1. Analysis of three geopressured geothermal aquifer-natural gas fields; Duson Hollywood and Church Point, Louisiana

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, L.A.; Boardman, C.R.

    1981-05-01

    The available well logs, production records and geological structure maps were analyzed for the Hollywood, Duson, and Church Point, Louisiana oil and gas field to determine the areal extent of the sealed geopressured blocks and to identify which aquifer sands within the blocks are connected to commercial production of hydrocarbons. The analysis showed that over the depth intervals of the geopressured zones shown on the logs essentially all of the sands of any substantial thickness had gas production from them somewhere or other in the fault block. It is therefore expected that the sands which are fully brine saturated in many of the wells are the water drive portion of the producing gas/oil somewhere else within the fault block. In this study only one deep sand was identified, in the Hollywood field, which was not connected to a producing horizon somewhere else in the field. Estimates of the reservoir parameters were made and a hypothetical production calculation showed the probable production to be less than 10,000 b/d. The required gas price to profitably produce this gas is well above the current market price.

  2. A meta-analysis of leaf gas exchange and water status responses to drought.

    Science.gov (United States)

    Yan, Weiming; Zhong, Yangquanwei; Shangguan, Zhouping

    2016-02-12

    Drought is considered to be one of the most devastating natural hazards, and it is predicted to become increasingly frequent and severe in the future. Understanding the plant gas exchange and water status response to drought is very important with regard to future climate change. We conducted a meta-analysis based on studies of plants worldwide and aimed to determine the changes in gas exchange and water status under different drought intensities (mild, moderate and severe), different photosynthetic pathways (C3 and C4) and growth forms (herbs, shrubs, trees and lianas). Our results were as follows: 1) drought negatively impacted gas exchange and water status, and stomatal conductance (gs) decreased more than other physiological traits and declined to the greatest extent in shrubs and C3 plants. Furthermore, C4 plants had an advantage compared to C3 plants under the same drought conditions. 2) The decrease in gs mainly reduced the transpiration rate (Tr), and gs could explain 55% of the decrease in the photosynthesis (A) and 74% of the decline in Tr. 3). Finally, gas exchange showed a close relationship with the leaf water status. Our study provides comprehensive information about the changes in plant gas exchange and water status under drought.

  3. Analysis of reactivity accidents of the RSG-GAS core with silicide fuel

    International Nuclear Information System (INIS)

    Tukiran

    2002-01-01

    The fuels of RSG-GAS reactor is changed from uranium oxide to uranium silicide. For time being, the fuel of RSG-GAS core are mixed up between oxide and silicide fuels with 250 gr of loading and 2.96 g U/cm 3 of density, respectively. While, silicide fuel with 300 gr of loading is still under research. The advantages of silicide fuels are can be used in high density, so that, it can be stayed longer in the core at higher burn-up, therefore, the length of cycle is longer. The silicide fuel in RSG-GAS core is used in step-wise by using mixed up core. Firstly, it is used silicide fuel with 250 gr of loading and then, silicide fuel with 300 gr of loading (3.55 g U/cm 3 of density). In every step-wise of fuel loading must be analysed its safety margin. In this occasion, it is analysed the reactivity accident of RSG-GAS core with 300 gr of silicide fuel loading. The calculation was done by using POKDYN code which available at P2TRR. The calculation was done by reactivity insertion at start up and power rangers. From all cases which were have been done, the results of analysis showed that there is no anomaly and safety margin break at RSG-GAS core with 300 gr silicide fuel loading

  4. Gas analysis within remote porous targets using LIDAR multi-scatter techniques

    Science.gov (United States)

    Guan, Z. G.; Lewander, M.; Grönlund, R.; Lundberg, H.; Svanberg, S.

    2008-11-01

    Light detection and ranging (LIDAR) experiments are normally pursued for range resolved atmospheric gas measurements or for analysis of solid target surfaces using fluorescence of laser-induced breakdown spectroscopy. In contrast, we now demonstrate the monitoring of free gas enclosed in pores of materials, subject to impinging laser radiation, employing the photons emerging back to the surface laterally of the injection point after penetrating the medium in heavy multiple scattering processes. The directly reflected light is blocked by a beam stop. The technique presented is a remote version of the newly introduced gas in scattering media absorption spectroscopy (GASMAS) technique, which so far was pursued with the injection optics and the detector in close contact with the sample. Feasibility measurements of LIDAR-GASMAS on oxygen in polystyrene foam were performed at a distance of 6 m. Multiple-scattering induced delays of the order of 50 ns, which corresponds to 15 m optical path length, were observed. First extensions to a range of 60 m are discussed. Remote observation of gas composition anomalies in snow using differential absorption LIDAR (DIAL) may find application in avalanche victim localization or for leak detection in snow-covered natural gas pipelines. Further, the techniques may be even more useful for short-range, non-intrusive GASMAS measurements, e.g., on packed food products.

  5. A Mathematical Pressure Transient Analysis Model for Multiple Fractured Horizontal Wells in Shale Gas Reservoirs

    Directory of Open Access Journals (Sweden)

    Yan Zeng

    2018-01-01

    Full Text Available Multistage fractured horizontal wells (MFHWs have become the main technology for shale gas exploration. However, the existing models have neglected the percolation mechanism in nanopores of organic matter and failed to consider the differences among the reservoir properties in different areas. On that account, in this study, a modified apparent permeability model was proposed describing gas flow in shale gas reservoirs by integrating bulk gas flow in nanopores and gas desorption from nanopores. The apparent permeability was introduced into the macroseepage model to establish a dynamic pressure analysis model for MFHWs dual-porosity formations. The Laplace transformation and the regular perturbation method were used to obtain an analytical solution. The influences of fracture half-length, fracture permeability, Langmuir volume, matrix radius, matrix permeability, and induced fracture permeability on pressure and production were discussed. Results show that fracture half-length, fracture permeability, and induced fracture permeability exert a significant influence on production. A larger Langmuir volume results in a smaller pressure and pressure derivative. An increase in matrix permeability increases the production rate. Besides, this model fits the actual field data relatively well. It has a reliable theoretical foundation and can preferably describe the dynamic changes of pressure in the exploration process.

  6. Numerical Analysis of Turbulent Combustion in a Model Swirl Gas Turbine Combustor

    Directory of Open Access Journals (Sweden)

    Ali Cemal Benim

    2016-01-01

    Full Text Available Turbulent reacting flows in a generic swirl gas turbine combustor are investigated numerically. Turbulence is modelled by a URANS formulation in combination with the SST turbulence model, as the basic modelling approach. For comparison, URANS is applied also in combination with the RSM turbulence model to one of the investigated cases. For this case, LES is also used for turbulence modelling. For modelling turbulence-chemistry interaction, a laminar flamelet model is used, which is based on the mixture fraction and the reaction progress variable. This model is implemented in the open source CFD code OpenFOAM, which has been used as the basis for the present investigation. For validation purposes, predictions are compared with the measurements for a natural gas flame with external flue gas recirculation. A good agreement with the experimental data is observed. Subsequently, the numerical study is extended to syngas, for comparing its combustion behavior with that of natural gas. Here, the analysis is carried out for cases without external flue gas recirculation. The computational model is observed to provide a fair prediction of the experimental data and predict the increased flashback propensity of syngas.

  7. The role of fission gas in the analysis of hypothetical core disruptive accidents

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, E A [Gesellschaft fuer Kernforschung mbH, INR Kernforschungszentrum, Karlsruhe (Germany)

    1977-07-01

    This paper summarizes recent work at Karlsruhe with the goal of understanding the effects of fission gas in hypothetical core disruptive accidents. The fission gas behavior model is discussed. The computer programs LANGZEIT and KURZZEIT describe the long-term and the transient gas behavior, respectively. Recent improvements in the modeling and a comparison of results with experimental data are reported. A somewhat detailed study of the role of fission gas in transient overpower (TOP) accidents was carried out. If pessimistic assumptions, like pin failure near the axial midplane are made, these accidents end in core disassembly. The codes HOPE and KADIS were used to analyze the initiating and the disassembly phase in these studies. Improvements of the codes are discussed. They include an automatic data transfer from HOPE to KADIS, and a new equation of state in KADIS, with an improved model for fission gas behavior. The analysis of a 15 cents/sec reactivity ramp accident is presented. Different pin failure criteria are used. In the cases selected, the codes predict an energetic disassembly. For the much discussed loss-of-flow driven TOP, detailed models are presently not available at Karlsruhe. Therefore, only a few comments and the results of a few scoping calculations will be presented.

  8. Simulation and Parametric Analysis of a Hybrid SOFC-Gas Turbine Power Generation System

    International Nuclear Information System (INIS)

    Hassan, A.M.; Fahmy

    2004-01-01

    Combined SOFC-Gas Turbine Power Generation Systems are aimed to increase the power and efficiency obtained from the technology of using high temperature fuel cells by integrating them with gas turbines. Hybrid systems are considered in the last few years as one of the most promising technologies to obtain electric energy from the natural gas at very high efficiency with a serious potential for commercial use. The use of high temperature allows internal reforming for natural gas and thus disparity of fuel composition is allowed. Also air preheating is performed thanks to the high operating cell temperature as a task of energy integration. In this paper a modeling approach is presented for the fuel cell-gas turbine hybrid power generation systems, to obtain the sofc output voltage, power, and the overall hybrid system efficiency. The system has been simulated using HYSYS, the process simulation software to help improving the process understanding and provide a quick system solution. Parametric analysis is also presented in this paper to discuss the effect of some important SOFC operating parameters on the system performance and efficiency

  9. Thermodynamic analysis of a combined gas turbine, ORC cycle and absorption refrigeration for a CCHP system

    International Nuclear Information System (INIS)

    Mohammadi, Amin; Kasaeian, Alibakhsh; Pourfayaz, Fathollah; Ahmadi, Mohammad Hossein

    2017-01-01

    Highlights: • Thermodynamic analysis of a hybrid CCHP system. • Sensitivity analysis is performed on the most important parameters of the system. • Pressure ratio and gas turbine inlet temperature are the most effective parameters. - Abstract: Hybrid power systems are gained more attention due to their better performance and higher efficiency. Widespread use of these systems improves environmental situation as they reduce the amount of fossil fuel consumption. In this paper a hybrid system composed of a gas turbine, an ORC cycle and an absorption refrigeration cycle is proposed as a combined cooling, heating and power system for residential usage. Thermodynamic analysis is applied on the system. Also a parametric analysis is carried out to investigate the effect of different parameters on the system performance and output cooling, heating and power. The results show that under design conditions, the proposed plant can produce 30 kW power, 8 kW cooling and almost 7.2 ton hot water with an efficiency of 67.6%. Moreover, parametric analysis shows that pressure ratio and gas turbine inlet temperature are the most important and influential parameters. After these two, ORC turbine inlet temperature is the most effective parameter as it can change both net output power and energy efficiency of the system.

  10. Economic analysis of multiple-module high temperature gas-cooled reactor (MHTR) nuclear power plants

    International Nuclear Information System (INIS)

    Liu Yu; Dong Yujie

    2011-01-01

    In recent years, as the increasing demand of energy all over the world, and the pressure on greenhouse emissions, there's a new opportunity for the development of nuclear energy. Modular High Temperature Gas-cooled Reactor (MHTR) received recognition for its inherent safety feature and high outlet temperature. Whether the Modular High Temperature Gas-cooled Reactor would be accepted extensively, its economy is a key point. In this paper, the methods of qualitative analysis and the method of quantitative analysis, the economic models designed by Economic Modeling Working Group (EMWG) of the Generation IV International Forum (GIF), as well as the HTR-PM's main technical features, are used to analyze the economy of the MHTR. A prediction is made on the basis of summarizing High Temperature Gas-cooled Reactor module characteristics, construction cost, total capital cost, fuel cost and operation and maintenance (O and M) cost and so on. In the following part, comparative analysis is taken measures to the economy and cost ratio of different designs, to explore the impacts of modularization and standardization on the construction of multiple-module reactor nuclear power plant. Meanwhile, the analysis is also adopted in the research of key factors such as the learning effect and yield to find out their impacts on the large scale development of MHTR. Furthermore, some reference would be provided to its wide application based on these analysis. (author)

  11. Mobile computing acceptance grows as applications evolve.

    Science.gov (United States)

    Porn, Louis M; Patrick, Kelly

    2002-01-01

    Handheld devices are becoming more cost-effective to own, and their use in healthcare environments is increasing. Handheld devices currently are being used for e-prescribing, charge capture, and accessing daily schedules and reference tools. Future applications may include education on medications, dictation, order entry, and test-results reporting. Selecting the right handheld device requires careful analysis of current and future applications, as well as vendor expertise. It is important to recognize the technology will continue to evolve over the next three years.

  12. Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

    Directory of Open Access Journals (Sweden)

    Shams Bilal

    2017-08-01

    Full Text Available Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large amount of condensate in reservoir pores. Trapped condensate often is lost due to condensate accumulation-condensate blockage courtesy of high molecular weight, heavy condensate residue. Recovering lost condensate most economically and optimally has always been a challenging goal. Thus, gas cycling is applied to alleviate such a drastic loss in resources.

  13. Comparative sequence analysis of Solanum and Arabidopsis in a hot spot for pathogen resistance on potato chromosome V reveals a patchwork of conserved and rapidly evolving genome segments

    Directory of Open Access Journals (Sweden)

    Bruggmann Rémy

    2007-05-01

    Full Text Available Abstract Background Quantitative phenotypic variation of agronomic characters in crop plants is controlled by environmental and genetic factors (quantitative trait loci = QTL. To understand the molecular basis of such QTL, the identification of the underlying genes is of primary interest and DNA sequence analysis of the genomic regions harboring QTL is a prerequisite for that. QTL mapping in potato (Solanum tuberosum has identified a region on chromosome V tagged by DNA markers GP21 and GP179, which contains a number of important QTL, among others QTL for resistance to late blight caused by the oomycete Phytophthora infestans and to root cyst nematodes. Results To obtain genomic sequence for the targeted region on chromosome V, two local BAC (bacterial artificial chromosome contigs were constructed and sequenced, which corresponded to parts of the homologous chromosomes of the diploid, heterozygous genotype P6/210. Two contiguous sequences of 417,445 and 202,781 base pairs were assembled and annotated. Gene-by-gene co-linearity was disrupted by non-allelic insertions of retrotransposon elements, stretches of diverged intergenic sequences, differences in gene content and gene order. The latter was caused by inversion of a 70 kbp genomic fragment. These features were also found in comparison to orthologous sequence contigs from three homeologous chromosomes of Solanum demissum, a wild tuber bearing species. Functional annotation of the sequence identified 48 putative open reading frames (ORF in one contig and 22 in the other, with an average of one ORF every 9 kbp. Ten ORFs were classified as resistance-gene-like, 11 as F-box-containing genes, 13 as transposable elements and three as transcription factors. Comparing potato to Arabidopsis thaliana annotated proteins revealed five micro-syntenic blocks of three to seven ORFs with A. thaliana chromosomes 1, 3 and 5. Conclusion Comparative sequence analysis revealed highly conserved collinear regions

  14. Analysis of resource potential for China’s unconventional gas and forecast for its long-term production growth

    International Nuclear Information System (INIS)

    Wang, Jianliang; Mohr, Steve; Feng, Lianyong; Liu, Huihui; Tverberg, Gail E.

    2016-01-01

    China is vigorously promoting the development of its unconventional gas resources because natural gas is viewed as a lower-carbon energy source and because China has relatively little conventional natural gas supply. In this paper, we first evaluate how much unconventional gas might be available based on an analysis of technically recoverable resources for three types of unconventional gas resources: shale gas, coalbed methane and tight gas. We then develop three alternative scenarios of how this extraction might proceed, using the Geologic Resources Supply Demand Model. Based on our analysis, the medium scenario, which we would consider to be our best estimate, shows a resource peak of 176.1 billion cubic meters (bcm) in 2068. Depending on economic conditions and advance in extraction techniques, production could vary greatly from this. If economic conditions are adverse, unconventional natural gas production could perhaps be as low as 70.1 bcm, peaking in 2021. Under the extremely optimistic assumption that all of the resources that appear to be technologically available can actually be recovered, unconventional production could amount to as much as 469.7 bcm, with peak production in 2069. Even if this high scenario is achieved, China’s total gas production will only be sufficient to meet China’s lowest demand forecast. If production instead matches our best estimate, significant amounts of natural gas imports are likely to be needed. - Highlights: • A comprehensive investigation on China’s unconventional gas resources is presented. • China’s unconventional gas production is forecast under different scenarios. • Unconventional gas production will increase rapidly in high scenario. • Achieving the projected production in high scenario faces many challenges. • The increase of China’s unconventional gas production cannot solve its gas shortage.

  15. The 'E' factor -- evolving endodontics.

    Science.gov (United States)

    Hunter, M J

    2013-03-01

    Endodontics is a constantly developing field, with new instruments, preparation techniques and sealants competing with trusted and traditional approaches to tooth restoration. Thus general dental practitioners must question and understand the significance of these developments before adopting new practices. In view of this, the aim of this article, and the associated presentation at the 2013 British Dental Conference & Exhibition, is to provide an overview of endodontic methods and constantly evolving best practice. The presentation will review current preparation techniques, comparing rotary versus reciprocation, and question current trends in restoration of the endodontically treated tooth.

  16. Humidity independent mass spectrometry for gas phase chemical analysis via ambient proton transfer reaction.

    Science.gov (United States)

    Zhu, Hongying; Huang, Guangming

    2015-03-31

    In this work, a humidity independent mass spectrometric method was developed for rapid analysis of gas phase chemicals. This method is based upon ambient proton transfer reaction between gas phase chemicals and charged water droplets, in a reaction chamber with nearly saturate humidity under atmospheric pressure. The humidity independent nature enables direct and rapid analysis of raw gas phase samples, avoiding time- and sample-consuming sample pretreatments in conventional mass spectrometry methods to control sample humidity. Acetone, benzene, toluene, ethylbenzene and meta-xylene were used to evaluate the analytical performance of present method. The limits of detection for benzene, toluene, ethylbenzene and meta-xylene are in the range of ∼0.1 to ∼0.3 ppbV; that of benzene is well below the present European Union permissible exposure limit for benzene vapor (5 μg m(-3), ∼1.44 ppbV), with linear ranges of approximately two orders of magnitude. The majority of the homemade device contains a stainless steel tube as reaction chamber and an ultrasonic humidifier as the source of charged water droplets, which makes this cheap device easy to assemble and facile to operate. In addition, potential application of this method was illustrated by the real time identification of raw gas phase chemicals released from plants at different physiological stages. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Comprehensive Analysis of the Gas- and Particle-Phase Products of VOC Oxidation

    Science.gov (United States)

    Bakker-Arkema, J.; Ziemann, P. J.

    2017-12-01

    Controlled environmental chamber studies are important for determining atmospheric reaction mechanisms and gas and aerosol products formed in the oxidation of volatile organic compounds (VOCs). Such information is necessary for developing detailed chemical models for use in predicting the atmospheric fate of VOCs and also secondary organic aerosol (SOA) formation. However, complete characterization of atmospheric oxidation reactions, including gas- and particle-phase product yields, and reaction branching ratios, are difficult to achieve. In this work, we investigated the reactions of terminal and internal alkenes with OH radicals in the presence of NOx in an attempt to fully characterize the chemistry of these systems while minimizing and accounting for the inherent uncertainties associated with environmental chamber experiments. Gas-phase products (aldehydes formed by alkoxy radical decomposition) and particle-phase products (alkyl nitrates, β-hydroxynitrates, dihydroxynitrates, 1,4-hydroxynitrates, 1,4-hydroxycarbonyls, and dihydroxycarbonyls) formed through pathways involving addition of OH to the C=C double bond as well as H-atom abstraction were identified and quantified using a suite of analytical techniques. Particle-phase products were analyzed in real time with a thermal desorption particle beam mass spectrometer; and off-line by collection onto filters, extraction, and subsequent analysis of functional groups by derivatization-spectrophotometric methods developed in our lab. Derivatized products were also separated by liquid chromatography for molecular quantitation by UV absorbance and identification using chemical ionization-ion trap mass spectrometry. Gas phase aldehydes were analyzed off-line by collection onto Tenax and a 5-channel denuder with subsequent analysis by gas chromatography, or by collection onto DNPH-coated cartridges and subsequent analysis by liquid chromatography. The full product identification and quantitation, with careful

  18. Pseudo-absolute quantitative analysis using gas chromatography – Vacuum ultraviolet spectroscopy – A tutorial

    International Nuclear Information System (INIS)

    Bai, Ling; Smuts, Jonathan; Walsh, Phillip; Qiu, Changling; McNair, Harold M.; Schug, Kevin A.

    2017-01-01

    The vacuum ultraviolet detector (VUV) is a new non-destructive mass sensitive detector for gas chromatography that continuously and rapidly collects full wavelength range absorption between 120 and 240 nm. In addition to conventional methods of quantification (internal and external standard), gas chromatography - vacuum ultraviolet spectroscopy has the potential for pseudo-absolute quantification of analytes based on pre-recorded cross sections (well-defined absorptivity across the 120–240 nm wavelength range recorded by the detector) without the need for traditional calibration. The pseudo-absolute method was used in this research to experimentally evaluate the sources of sample loss and gain associated with sample introduction into a typical gas chromatograph. Standard samples of benzene and natural gas were used to assess precision and accuracy for the analysis of liquid and gaseous samples, respectively, based on the amount of analyte loaded on-column. Results indicate that injection volume, split ratio, and sampling times for splitless analysis can all contribute to inaccurate, yet precise sample introduction. For instance, an autosampler can very reproducibly inject a designated volume, but there are significant systematic errors (here, a consistently larger volume than that designated) in the actual volume introduced. The pseudo-absolute quantification capability of the vacuum ultraviolet detector provides a new means for carrying out system performance checks and potentially for solving challenging quantitative analytical problems. For practical purposes, an internal standardized approach to normalize systematic errors can be used to perform quantitative analysis with the pseudo-absolute method. - Highlights: • Gas chromatography diagnostics and quantification using VUV detector. • Absorption cross-sections for molecules enable pseudo-absolute quantitation. • Injection diagnostics reveal systematic errors in hardware settings. • Internal

  19. Pseudo-absolute quantitative analysis using gas chromatography – Vacuum ultraviolet spectroscopy – A tutorial

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Ling [Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, TX (United States); Smuts, Jonathan; Walsh, Phillip [VUV Analytics, Inc., Cedar Park, TX (United States); Qiu, Changling [Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, TX (United States); McNair, Harold M. [Department of Chemistry, Virginia Tech, Blacksburg, VA (United States); Schug, Kevin A., E-mail: kschug@uta.edu [Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, TX (United States)

    2017-02-08

    The vacuum ultraviolet detector (VUV) is a new non-destructive mass sensitive detector for gas chromatography that continuously and rapidly collects full wavelength range absorption between 120 and 240 nm. In addition to conventional methods of quantification (internal and external standard), gas chromatography - vacuum ultraviolet spectroscopy has the potential for pseudo-absolute quantification of analytes based on pre-recorded cross sections (well-defined absorptivity across the 120–240 nm wavelength range recorded by the detector) without the need for traditional calibration. The pseudo-absolute method was used in this research to experimentally evaluate the sources of sample loss and gain associated with sample introduction into a typical gas chromatograph. Standard samples of benzene and natural gas were used to assess precision and accuracy for the analysis of liquid and gaseous samples, respectively, based on the amount of analyte loaded on-column. Results indicate that injection volume, split ratio, and sampling times for splitless analysis can all contribute to inaccurate, yet precise sample introduction. For instance, an autosampler can very reproducibly inject a designated volume, but there are significant systematic errors (here, a consistently larger volume than that designated) in the actual volume introduced. The pseudo-absolute quantification capability of the vacuum ultraviolet detector provides a new means for carrying out system performance checks and potentially for solving challenging quantitative analytical problems. For practical purposes, an internal standardized approach to normalize systematic errors can be used to perform quantitative analysis with the pseudo-absolute method. - Highlights: • Gas chromatography diagnostics and quantification using VUV detector. • Absorption cross-sections for molecules enable pseudo-absolute quantitation. • Injection diagnostics reveal systematic errors in hardware settings. • Internal

  20. Canadian family physician job satisfaction - is it changing in an evolving practice environment? An analysis of the 2013 National Physician Survey database.

    Science.gov (United States)

    Malhotra, Jana; Wong, Eric; Thind, Amardeep

    2018-06-23

    To explore the determinants of job satisfaction and work-life balance satisfaction of family physicians in Canada. This is a secondary analysis of the Canadian 2013 National Physician's Survey using descriptive statistics and binomial logistic regression. An estimated 34,753 family physicians practicing in Canada at the time of survey administration in 2013 were eligible for the survey. The main outcome measures were respondent satisfaction with professional life and satisfaction with work-life balance. The survey had a response rate of 17%. Seventy-two percent of respondents were satisfied with their professional lives, and 49% were satisfied with their work-life balance. Male family physicians had lower odds of satisfaction with their work-life balance than their female counterparts (OR = 0.86, 95% CI 0.82-0.92). Family physicians using an electronic medical record had higher odds of dissatisfaction with their professional lives (OR = 1.13, 95% CI 1.05-1.22) and work-life balance (OR = 1.22, 95% CI 1.15-1.30) than those not using an EMR. Family physicians not in a focused practice had greater odds of dissatisfaction (OR = 1.61, 95% CI 1.50-1.72) with both their professional lives and work-life balance (OR = 1.29, 95% CI 1.22-1.37) compared to their colleagues who have one or more areas of clinical focus. Canadian family physicians are more satisfied with their professional lives than with their work-life balance. Novel findings that family physicians with one or more clinical areas of focus are more satisfied with their work and work-life balance satisfaction, and that family physicians using electronic health records are less satisfied with their work and their work-life balance merit further inquiry.

  1. Wavelength modulation spectroscopy--digital detection of gas absorption harmonics based on Fourier analysis.

    Science.gov (United States)

    Mei, Liang; Svanberg, Sune

    2015-03-20

    This work presents a detailed study of the theoretical aspects of the Fourier analysis method, which has been utilized for gas absorption harmonic detection in wavelength modulation spectroscopy (WMS). The lock-in detection of the harmonic signal is accomplished by studying the phase term of the inverse Fourier transform of the Fourier spectrum that corresponds to the harmonic signal. The mathematics and the corresponding simulation results are given for each procedure when applying the Fourier analysis method. The present work provides a detailed view of the WMS technique when applying the Fourier analysis method.

  2. Revisiting Robustness and Evolvability: Evolution in Weighted Genotype Spaces

    Science.gov (United States)

    Partha, Raghavendran; Raman, Karthik

    2014-01-01

    Robustness and evolvability are highly intertwined properties of biological systems. The relationship between these properties determines how biological systems are able to withstand mutations and show variation in response to them. Computational studies have explored the relationship between these two properties using neutral networks of RNA sequences (genotype) and their secondary structures (phenotype) as a model system. However, these studies have assumed every mutation to a sequence to be equally likely; the differences in the likelihood of the occurrence of various mutations, and the consequence of probabilistic nature of the mutations in such a system have previously been ignored. Associating probabilities to mutations essentially results in the weighting of genotype space. We here perform a comparative analysis of weighted and unweighted neutral networks of RNA sequences, and subsequently explore the relationship between robustness and evolvability. We show that assuming an equal likelihood for all mutations (as in an unweighted network), underestimates robustness and overestimates evolvability of a system. In spite of discarding this assumption, we observe that a negative correlation between sequence (genotype) robustness and sequence evolvability persists, and also that structure (phenotype) robustness promotes structure evolvability, as observed in earlier studies using unweighted networks. We also study the effects of base composition bias on robustness and evolvability. Particularly, we explore the association between robustness and evolvability in a sequence space that is AU-rich – sequences with an AU content of 80% or higher, compared to a normal (unbiased) sequence space. We find that evolvability of both sequences and structures in an AU-rich space is lesser compared to the normal space, and robustness higher. We also observe that AU-rich populations evolving on neutral networks of phenotypes, can access less phenotypic variation compared to

  3. Analysis of a gas turbine driven hybrid drive system for heavy vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Malmquist, Anders

    1999-07-01

    The goal of this thesis has been to analyze the performance and behavior of a gas turbine driven hybrid drive train. The thesis covers both computer simulations and experimental tests. In two case studies, a number of measurements have been made on gas turbine driven hybrid vehicles that are developed by Volvo and ABB. In the recent years, much effort is currently put into the design and analysis of hybrid drive trains. Many studies involve computer simulations, but they are often made on a general level. This thesis concentrate on gas turbine driven hybrids for heavy vehicles, a field that has previously not been covered to a large extent in academic studies. A major contribution to the field of hybrid drive train design is the development of detailed simulation models that have a close connection to hybrids that are actually built and tested. The access to detailed gas turbine data has further enhanced the possibility to design a dynamic model of the gas turbine driven and the electric circuits. The combination of simulations and extensive field experience gains new knowledge on the properties of gas turbines in hybrid drive trains. Two simulation models have been developed in Matlab and Simulink. One is a quasi-steady state model that can be used for drive cycle simulations, e.g. a complete bus line. The other is a transient model that combines the thermodynamic properties of the gas turbine, the mechanical properties of the combined turbine-generator shaft, the electric power circuit and the control system. The transient model has been used to simulate the power response during accelerations and retardation. An analysis of the internal energy flows and the system efficiency of a hybrid drive train contributes to the understanding of the properties of series hybrid drive trains. An important part of the topology is that the system is based on a DC/DC-converter that is connected between the battery and the DC-bus. It controls the DC-bus voltage and by this

  4. Spectrum analysis of national greenhouse gas emission: a case study of Germany

    Energy Technology Data Exchange (ETDEWEB)

    Su, Meirong [Dongguan University of Technology, School of Chemistry and Environmental Engineering, Dongguan, Guangdong Province (China); Beijing Normal University, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Beijing (China); Technical University of Munich, Strategic Landscape Planning and Management, Freising (Germany); Pauleit, Stephan; Xu, Chao [Technical University of Munich, Strategic Landscape Planning and Management, Freising (Germany)

    2016-10-15

    It is essential to abstract the key information from accounting results of greenhouse gas (GHG) emissions because it can provide a highly generalized and clear picture of GHG emissions, which is especially helpful for the public and policy makers. To clearly display the composition of GHG emissions, the concept of spectrum analysis is introduced and defined in this paper. Next, a multilayer analysis framework for national GHG emissions was proposed, which is represented by a pyramid of three layers: total emissions (first layer), emissions decomposed by gas type or sector (second layer), and emissions decomposed by both gas type and sector (third layer). Based on the analysis results from the first to third layers, the main compositional information of national GHG emissions was gradually summarized and analyzed until a spectrum of GHG emissions was acquired. The spectrum of GHG emissions displays the compositional structure of national GHG emissions in the different layers, which is helpful in identifying priorities for emissions reduction. A case study of Germany's GHG emissions during 1990-2012 was conducted, which indicated that CO{sub 2} and the energy sector were the biggest contributors to the total GHG emissions. Some suggestions for reducing GHG emissions are offered based on the obtained results. And the potential development of spectrum analysis for GHG emissions is also expected from aspects of both research and technology. (orig.)

  5. Spectrum analysis of national greenhouse gas emission: a case study of Germany

    International Nuclear Information System (INIS)

    Su, Meirong; Pauleit, Stephan; Xu, Chao

    2016-01-01

    It is essential to abstract the key information from accounting results of greenhouse gas (GHG) emissions because it can provide a highly generalized and clear picture of GHG emissions, which is especially helpful for the public and policy makers. To clearly display the composition of GHG emissions, the concept of spectrum analysis is introduced and defined in this paper. Next, a multilayer analysis framework for national GHG emissions was proposed, which is represented by a pyramid of three layers: total emissions (first layer), emissions decomposed by gas type or sector (second layer), and emissions decomposed by both gas type and sector (third layer). Based on the analysis results from the first to third layers, the main compositional information of national GHG emissions was gradually summarized and analyzed until a spectrum of GHG emissions was acquired. The spectrum of GHG emissions displays the compositional structure of national GHG emissions in the different layers, which is helpful in identifying priorities for emissions reduction. A case study of Germany's GHG emissions during 1990-2012 was conducted, which indicated that CO_2 and the energy sector were the biggest contributors to the total GHG emissions. Some suggestions for reducing GHG emissions are offered based on the obtained results. And the potential development of spectrum analysis for GHG emissions is also expected from aspects of both research and technology. (orig.)

  6. Origin and spatial distribution of gas at seismogenic depths of the San Andreas Fault from drill-mud gas analysis

    International Nuclear Information System (INIS)

    Wiersberg, Thomas; Erzinger, Joerg

    2008-01-01

    Data are presented on the molecular composition of drill-mud gas from the lower sedimentary section (1800-3987 m) of the SAFOD (San Andreas Fault Observatory at Depth) Main Hole measured on-line during drilling, as well as C and H isotope data from off-line mud gas samples. Hydrocarbons, H 2 and CO 2 are the most abundant non-atmospheric gases in drill-mud when drilling seismogenic zones. Gas influx into the well at depth is related to the lithology and permeability of the drilled strata: larger formation gas influx was detected when drilling through organic-rich shales and permeable sandstones. The SAF (San Andreas Fault), encountered between approximately 3100 m and 3450 m borehole depth, is generally low in gas, but is encompassed by two gas-rich zones (2700-2900 m and below 3550 m) at the fault margins with enhanced 222 Rn activities and distinct gas compositions. Within the fault, two interstratified gas-rich lenses (3150-3200 m and 3310-3340 m) consist of CO 2 and hydrocarbons (upper zone), but almost exclusively of hydrocarbons (lower zone). The isotopic composition indicates an organic source of hydrocarbons and CO 2 in the entire sedimentary section of the well. Hydrocarbons in sedimentary strata are partly of microbial origin down to ∼2500 m borehole depth. The contribution of thermogenic gas increases between ∼2500 m and 3200 m. Below ∼3200 m, hydrocarbons fully derive from thermal degradation of organic matter. The lack of H 2 in the center of the fault and the high concentration of H 2 in the fractured zones at the fault margins are consistent with H 2 formation by interaction of water with fresh silica mineral surfaces generated by tectonic activities, however, this needs to be verified by laboratory experiments. Based on these studies, it is concluded that the fault zone margins consist of strata with enhanced permeability, separated by a low-permeability fault center

  7. Life Cycle Greenhouse Gas Emissions from Electricity Generation: A Comparative Analysis of Australian Energy Sources

    Directory of Open Access Journals (Sweden)

    Robert G. Hynes

    2012-03-01

    Full Text Available Electricity generation is one of the major contributors to global greenhouse gas emissions. Transitioning the World’s energy economy to a lower carbon future will require significant investment in a variety of cleaner technologies, including renewables and nuclear power. In the short term, improving the efficiency of fossil fuel combustion in energy generation can provide an important contribution. Availability of life cycle GHG intensity data will allow decision-makers to move away from overly simplistic assertions about the relative merits of certain fuels, and focus on the complete picture, especially the critical roles of technology selection and application of best practice. This analysis compares the life-cycle greenhouse gas (GHG intensities per megawatt-hour (MWh of electricity produced for a range of Australian and other energy sources, including coal, conventional liquefied natural gas (LNG, coal seam gas LNG, nuclear and renewables, for the Australian export market. When Australian fossil fuels are exported to China, life cycle greenhouse gas emission intensity in electricity production depends to a significant degree on the technology used in combustion. LNG in general is less GHG intensive than black coal, but the gap is smaller for gas combusted in open cycle gas turbine plant (OCGT and for LNG derived from coal seam gas (CSG. On average, conventional LNG burned in a conventional OCGT plant is approximately 38% less GHG intensive over its life cycle than black coal burned in a sub-critical plant, per MWh of electricity produced. However, if OCGT LNG combustion is compared to the most efficient new ultra-supercritical coal power, the GHG intensity gap narrows considerably. Coal seam gas LNG is approximately 13–20% more GHG intensive across its life cycle, on a like-for like basis, than conventional LNG. Upstream fugitive emissions from CSG (assuming best practice gas extraction techniques do not materially alter the life cycle

  8. THE NIGERIAN GAS MASTER-PLAN, INVESTMENT OPPORTUNITIES, CHALLENGES, ISSUES AFFECTING POWER SECTOR: AN ANALYSIS

    Directory of Open Access Journals (Sweden)

    R. INGWE

    2014-11-01

    Full Text Available The Nigerian Gas Master-Plan, Investment Opportunities, Challenges, Issues Affecting Power Sector: an Analysis. The objective of this article is to contribute towards understanding of the Nigerian Gas Master Plan (NGMP/Plan and its bifurcations with key socio-economic development factors. I applied the method of discourse to bring to being some points that have hitherto been unknown about the Master-plan and its inter-relationships and bifurcations. Elaborated here are the spectacular gains that have accrued to the Latin American country, Trinidad and Tobago, from its recent development of natural gas resources. This was considered suitable and significant here for highlighting that if such spectacular achievements could be realized from Trinidad and Tobago’s relatively smaller gas deposit (15.3 tcf, probable reserves (8.4 tcf, possible reserves (6.2 tcf would be by far greater considering Nigeria’s larger natural gas reserves (184 tcf wealth as earlier stated. I show that the Plan is well designed relevant to addressing Nigeria’s current development needs generally. It presents potentials for stimulating Nigeria’s economic growth by harnessing the country’s abundant natural gas reserves. The Plan enumerates/ elaborates huge investment opportunities. Some challenges likely to be faced in the implementation/management of the Plan are already being surmounted as recent reports show that some of its key investments have been realized and the required infrastructure are being provided. Regarding the issues in the Master-plan that are likely to affect and are affecting Nigeria’s power sector development, I reckon that they are mostly positive factors due to the way the plan promises to stimulate electricity generation in our country.

  9. Analysis of residual swirl in tangentially-fired natural gas-boiler

    International Nuclear Information System (INIS)

    Hasril Hasini; Muhammad Azlan Muad; Mohd Zamri Yusoff; Norshah Hafeez Shuaib

    2010-01-01

    This paper describes the investigation on residual swirl flow in a 120 MW natural gas, full-scale, tangential-fired boiler. Emphasis is given towards the understanding of the behavior of the combustion gas flow pattern and temperature distribution as a result of the tangential firing system of the boiler. The analysis was carried out based on three-dimensional computational modeling on full scale boiler with validation from key design parameter as well as practical observation. Actual operating parameters of the actual boiler are taken as the boundary conditions for this modeling. The prediction of total heat flux was found to be in agreement with the key design parameter while the residual swirl predicted at the upper furnace agrees qualitatively with the practical observation. Based on this comparison, detail analysis was carried out for comprehensive understanding on the generation and destruction of the residual swirl behavior in boiler especially those with high capacity. (author)

  10. Thermal stress analysis and thermo-mechanical fatigue for gas turbine blade

    International Nuclear Information System (INIS)

    Hyun, J. S.; Kim, B. S.; Kang, M. S.; Ha, J. S.; Lee, Y. S.

    2002-01-01

    The numerical analysis for gas turbine blades were carried out under several conditions by compounding temperature field, velocity field, thermal conduction of blade, and cooling heat transfer. The three types of 1,100 deg. C class 1st-stage gas turbine blades were analyzed. The analysis results are applied to the study on evaluating the remaining life for thermo-mechanical fatigue life. The thermo-mechanical fatigue experiments under out-of-phase and in-phase have been performed. The physical-based life prediction models which considered the contribution of different damage mechanisms have been applied. These models were applied to the temperature and strain rate dependences of isothermal cycling fatigue lives, and the strain-temperature history effect on the thermo-mechanical fatigue lives

  11. [Recent advances in analysis of petroleum geological samples by comprehensive two-dimensional gas chromatography].

    Science.gov (United States)

    Gao, Xuanbo; Chang, Zhenyang; Dai, Wei; Tong, Ting; Zhang, Wanfeng; He, Sheng; Zhu, Shukui

    2014-10-01

    Abundant geochemical information can be acquired by analyzing the chemical compositions of petroleum geological samples. The information obtained from the analysis provides scientifical evidences for petroleum exploration. However, these samples are complicated and can be easily influenced by physical (e. g. evaporation, emulsification, natural dispersion, dissolution and sorption), chemical (photodegradation) and biological (mainly microbial degradation) weathering processes. Therefore, it is very difficult to analyze the petroleum geological samples and they cannot be effectively separated by traditional gas chromatography/mass spectrometry. A newly developed separation technique, comprehensive two-dimensional gas chromatography (GC x GC), has unique advantages in complex sample analysis, and recently it has been applied to petroleum geological samples. This article mainly reviews the research progres- ses in the last five years, the main problems and the future research about GC x GC applied in the area of petroleum geology.

  12. Optical design of multi-multiple expander structure of laser gas analysis and measurement device

    Science.gov (United States)

    Fu, Xiang; Wei, Biao

    2018-03-01

    The installation and debugging of optical circuit structure in the application of carbon monoxide distributed laser gas analysis and measurement, there are difficult key technical problems. Based on the three-component expansion theory, multi-multiple expander structure with expansion ratio of 4, 5, 6 and 7 is adopted in the absorption chamber to enhance the adaptability of the installation environment of the gas analysis and measurement device. According to the basic theory of aberration, the optimal design of multi-multiple beam expander structure is carried out. By using image quality evaluation method, the difference of image quality under different magnifications is analyzed. The results show that the optical quality of the optical system with the expanded beam structure is the best when the expansion ratio is 5-7.

  13. Performance Analysis of Joule-Thomson Cooler Supplied with Gas Mixtures

    Science.gov (United States)

    Piotrowska, A.; Chorowski, M.; Dorosz, P.

    2017-02-01

    Joule-Thomson (J-T) cryo-coolers working in closed cycles and supplied with gas mixtures are the subject of intensive research in different laboratories. The replacement of pure nitrogen by nitrogen-hydrocarbon mixtures allows to improve both thermodynamic parameters and economy of the refrigerators. It is possible to avoid high pressures in the heat exchanger and to use standard refrigeration compressor instead of gas bottles or high-pressure oil free compressor. Closed cycle and mixture filled Joule-Thomson cryogenic refrigerator providing 10-20 W of cooling power at temperature range 90-100 K has been designed and manufactured. Thermodynamic analysis including the optimization of the cryo-cooler mixture has been performed with ASPEN HYSYS software. The paper describes the design of the cryo-cooler and provides thermodynamic analysis of the system. The test results are presented and discussed.

  14. Theoretical analysis of stack gas emission velocity measurement by optical scintillation

    International Nuclear Information System (INIS)

    Yang Yang; Dong Feng-Zhong; Ni Zhi-Bo; Pang Tao; Zeng Zong-Yong; Wu Bian; Zhang Zhi-Rong

    2014-01-01

    Theoretical analysis for an online measurement of the stack gas flow velocity based on the optical scintillation method with a structure of two parallel optical paths is performed. The causes of optical scintillation in a stack are first introduced. Then, the principle of flow velocity measurement and its mathematical expression based on cross correlation of the optical scintillation are presented. The field test results show that the flow velocity measured by the proposed technique in this article is consistent with the value tested by the Pitot tube. It verifies the effectiveness of this method. Finally, by use of the structure function of logarithmic light intensity fluctuations, the theoretical explanation of optical scintillation spectral characteristic in low frequency is given. The analysis of the optical scintillation spectrum provides the basis for the measurement of the stack gas flow velocity and particle concentration simultaneously. (general)

  15. Design, fabrication and testing of the gas analysis system for the tritium recovery experiment, TRIO-01

    International Nuclear Information System (INIS)

    Finn, P.A.; Reedy, G.T.; Homa, M.I.; Clemmer, R.G.; Pappas, G.; Slawecki, M.A.; Graczyk, D.G.; Bowers, D.L.; Clemmer, E.D.

    1983-01-01

    The tritium recovery experiment, TRIO-01, required a gas analysis system which detected the form of tritium, the amount of tritium (differential and integral), and the presence and amount of other radioactive species. The system had to handle all contingencies and function for months at a time unattended during weekend operation. The designed system, described herein, consisted of a train of components which could be grouped as desired to match tritium release behavior

  16. Analysis of Bacterial Vaginosis-Related Amines in Vaginal Fluid by Gas Chromatography and Mass Spectrometry

    OpenAIRE

    Wolrath, Helen; Forsum, Urban; Larsson, P. G.; Borén, Hans

    2001-01-01

    The presence of various amines in vaginal fluid from women with malodorous vaginal discharge has been reported before. The investigations have used several techniques to identify the amines. However, an optimized quantification, together with a sensitive analysis method in connection with a diagnostic procedure for vaginal discharge, including the syndrome of bacterial vaginosis, as defined by the accepted “gold standard,” has not been done before. We now report a sensitive gas chromatographi...

  17. Numerical analysis of the thermally induced flow in a strongly rotating gas centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Novelli, P.

    1982-04-01

    The present work is concerned with the numerical analysis of the thermally induced flow in a rapidly gas centrifuge. The primary purpose for this work is to investigate the dependence of the flow field on the thermal boundary conditions, angular speed, aspect ratio of the cylinder, holdup. Some of our results are compared with the predictions of asymptotic theories, particularly those of Sakurai-Mtsuda and Brouwers, and with the numerical results of Dickinson-Jones.

  18. The adaptive internet application for interpretation of the transformer oil gas chromatographic analysis results

    Directory of Open Access Journals (Sweden)

    Polužanski Vladimir

    2015-01-01

    Full Text Available This paper describes an adaptive Internet application for the interpretation of the transformer oil gas chromatographic analysis results. The first version of the application is developed by following an evolutionary software development concept. The most important software development risks and the appropriate solutions are described. An open-source web framework named Bootstrap is used for an application implementation. The application is developed by using ASP.NET and MS SQL server.

  19. Evaluation and analysis method for natural gas hydrate storage and transportation processes

    International Nuclear Information System (INIS)

    Hao Wenfeng; Wang Jinqu; Fan Shuanshi; Hao Wenbin

    2008-01-01

    An evaluation and analysis method is presented to investigate an approach to scale-up a hydration reactor and to solve some economic problems by looking at the natural gas hydrate storage and transportation process as a whole. Experiments with the methane hydration process are used to evaluate the whole natural gas hydrate storage and transportation process. The specific contents and conclusions are as follows: first, batch stirring effects and load coefficients are studied in a semi-continuous stirred-tank reactor. Results indicate that batch stirring and appropriate load coefficients are effective in improving hydrate storage capacity. In the experiments, appropriate values for stirring velocity, stirring time and load coefficient were found to be 320 rpm, 30 min and 0.289, respectively. Second, throughput and energy consumption of the reactor for producing methane hydrates are calculated by mass and energy balance. Results show that throughput of this is 1.06 kg/d, with a product containing 12.4% methane gas. Energy consumption is 0.19 kJ, while methane hydrates containing 1 kJ heat are produced. Third, an energy consumption evaluation parameter is introduced to provide a single energy consumption evaluation rule for different hydration reactors. Parameter analyses indicate that process simplicity or process integration can decrease energy consumption. If experimental gas comes from a small-scale natural gas field and the energy consumption is 0.02 kJ when methane hydrates containing 1 kJ heat are produced, then the decrease is 87.9%. Moreover, the energy consumption evaluation parameter used as an economic criterion is converted into a process evaluation parameter. Analyses indicate that the process evaluation parameter is relevant to technology level and resource consumption for a system, which can make it applicable to economic analysis and venture forecasting for optimal capital utilization

  20. Optimum design and thermodynamic analysis of a gas turbine and ORC combined cycle with recuperators

    International Nuclear Information System (INIS)

    Cao, Yue; Gao, Yike; Zheng, Ya; Dai, Yiping

    2016-01-01

    Highlights: • A GT-ORC combined cycle with recuperators was designed. • The effect of the ORC turbine inlet pressure on the combined cycle was examined. • Toluene was a more suitable working fluid for the GT-ORC combined cycle. • The GT-ORC combined cycle performed better than the GT-Rankine combined cycle. • The sensitivity analysis to the ambient temperature was completed. - Abstract: Gas turbines are widely used in distributed power generation because of their high efficiency, low pollution and low operational cost. To further utilize the waste heat from gas turbines, an organic Rankine cycle (ORC) was proposed as the bottoming cycle for gas turbines in this paper. Two recuperators were coupled with the combined cycle to increase the thermal efficiency, and aromatics were chosen as the working fluid for the bottoming cycle. This paper focused on the optimum design and thermodynamic analysis of the gas turbine and ORC (GT-ORC) combined cycle. Results showed that the net power and thermal efficiency of the ORC increased with the ORC turbine inlet pressure and achieved optimum values at a specific pressure based on the optimum criteria. Furthermore, compared with the GT-Rankine combined cycle, the GT-ORC combined cycle had better thermodynamic performance. Toluene was a more suitable working fluid for the GT-ORC combined cycle. Moreover, ambient temperature sensitivity simulations concluded that the GT-ORC combined cycle had a maximum thermal efficiency and the combined cycle net power was mainly determined by the topping gas turbine cycle.