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Sample records for fuel mixture due

  1. Stabilizer for fuel mixtures

    SciTech Connect

    Abe, M.; Moriyama, N.; Yamamura, M.

    1981-02-24

    A stabilizer for fuel mixtures of finely divided coal and fuel oil is composed of an active ingredient, a non-ionic surface active agent consisting of a block copolymer represented by the following general formula (I): R/sub 1/O-(C/sub 2/H/sup 4/O)l-(C/sub 3/H/sup 6/O)m-(C/sub 2/H/sup 4/O)n-R/sub 2/ (I) wherein r/sub 1/ and r/sub 2/ stand for a hydrogen atom or an alklyl group having 1 to 6 carbon atoms, the mole number (L+n) of added ethylene oxide is in the range of from 30 to 300, the mole number (M) of added propylene oxide is in the range of from 15 to 80, and the content of ethylene oxide in the whole molecule is 40 to 85% by weight.

  2. Solid fuel oil mixtures

    SciTech Connect

    Rutter, P.R.; Veal, C.J.

    1984-11-27

    Fuel composition comprises 15 to 60% be weight, preferably 40 to 55%, of a friable solid fuel, e.g. coal, a stabilizing additive composition and a fuel oil. The additive comprises the combination of a polymer containing functional groups, e.g., maleinized polybutadiene, and a surfactant. The composition is suitable for use as a liquid fuel for industrial burners.

  3. Coal-water mixture fuel burner

    DOEpatents

    Brown, T.D.; Reehl, D.P.; Walbert, G.F.

    1985-04-29

    The present invention represents an improvement over the prior art by providing a rotating cup burner arrangement for use with a coal-water mixture fuel which applies a thin, uniform sheet of fuel onto the inner surface of the rotating cup, inhibits the collection of unburned fuel on the inner surface of the cup, reduces the slurry to a collection of fine particles upon discharge from the rotating cup, and further atomizes the fuel as it enters the combustion chamber by subjecting it to the high shear force of a high velocity air flow. Accordingly, it is an object of the present invention to provide for improved combustion of a coal-water mixture fuel. It is another object of the present invention to provide an arrangement for introducing a coal-water mixture fuel into a combustion chamber in a manner which provides improved flame control and stability, more efficient combustion of the hydrocarbon fuel, and continuous, reliable burner operation. Yet another object of the present invention is to provide for the continuous, sustained combustion of a coal-water mixture fuel without the need for a secondary combustion source such as natural gas or a liquid hydrocarbon fuel. Still another object of the present invention is to provide a burner arrangement capable of accommodating a coal-water mixture fuel having a wide range of rheological and combustion characteristics in providing for its efficient combustion. 7 figs.

  4. Dual-water mixture fuel burner

    DOEpatents

    Brown, Thomas D.; Reehl, Douglas P.; Walbert, Gary F.

    1986-08-05

    A coal-water mixture (CWM) burner includes a conically shaped rotating cup into which fuel comprised of coal particles suspended in a slurry is introduced via a first, elongated inner tube coupled to a narrow first end portion of the cup. A second, elongated outer tube is coaxially positioned about the first tube and delivers steam to the narrow first end of the cup. The fuel delivery end of the inner first tube is provided with a helical slot on its lateral surface for directing the CWM onto the inner surface of the rotating cup in the form of a uniform, thin sheet which, under the influence of the cup's centrifugal force, flows toward a second, open, expanded end portion of the rotating cup positioned immediately adjacent to a combustion chamber. The steam delivered to the rotating cup wets its inner surface and inhibits the coal within the CWM from adhering to the rotating cup. A primary air source directs a high velocity air flow coaxially about the expanded discharge end of the rotating cup for applying a shear force to the CWM in atomizing the fuel mixture for improved combustion. A secondary air source directs secondary air into the combustion chamber adjacent to the outlet of the rotating cup at a desired pitch angle relative to the fuel mixture/steam flow to promote recirculation of hot combustion gases within the ignition zone for increased flame stability.

  5. Examination of physical properties of fuels and mixtures with alternative fuels

    NASA Astrophysics Data System (ADS)

    Lown, Anne Lauren

    ABSTRACT. EXAMINATION OF PHYSICAL PROPERTIES OF FUELS AND MIXTURES WITH ALTERNATIVE FUELS. By. Anne Lauren Lown. The diversity of alternative fuels is increasing due to new second generation biofuels. By modeling alternative fuels and fuel mixtures, types of fuels can be selected based on their properties, without producing and testing large batches. A number of potential alternative fuels have been tested and modeled to determine their impact when blended with traditional diesel and jet fuels. The properties evaluated include cloud point and pour point temperature, cetane number, distillation curve, and speed of sound. This work represents a novel approach to evaluating the properties of alternative fuels and their mixtures with petroleum fuels. Low temperature properties were evaluated for twelve potential biofuel compounds in mixtures with three diesel fuels and one jet fuel. Functional groups tested included diesters, esters, ketones, and ethers, and alkanes were used for comparison. Alkanes, ethers, esters, and ketones with a low melting point temperature were found to decrease the fuel cloud point temperature. Diesters added to fuels display an upper critical solution temperature, and multiple methods were used to confirm the presence of liquid-liquid immiscibility. These behaviors are independent of chain length and branching, as long as the melting point temperature of the additive is not significantly higher than the cloud point temperature of the fuel. Physical properties were estimated for several potential fuel additive molecules using group contribution methods. Quantum chemical calculations were used for ideal gas heat capacities. Fuel surrogates for three petroleum based fuels and six alternative fuels were developed. The cloud point temperature, distillation curve, cetane number, and average molecular weight for different fuel surrogates were simultaneously represented. The proposed surrogates use the experimental mass fractions of paraffins, and

  6. Nuclear fuel alloys or mixtures and method of making thereof

    DOEpatents

    Mariani, Robert Dominick; Porter, Douglas Lloyd

    2016-04-05

    Nuclear fuel alloys or mixtures and methods of making nuclear fuel mixtures are provided. Pseudo-binary actinide-M fuel mixtures form alloys and exhibit: body-centered cubic solid phases at low temperatures; high solidus temperatures; and/or minimal or no reaction or inter-diffusion with steel and other cladding materials. Methods described herein through metallurgical and thermodynamics advancements guide the selection of amounts of fuel mixture components by use of phase diagrams. Weight percentages for components of a metallic additive to an actinide fuel are selected in a solid phase region of an isothermal phase diagram taken at a temperature below an upper temperature limit for the resulting fuel mixture in reactor use. Fuel mixtures include uranium-molybdenum-tungsten, uranium-molybdenum-tantalum, molybdenum-titanium-zirconium, and uranium-molybdenum-titanium systems.

  7. Air-fuel mixture ratio control using electrostatic force

    SciTech Connect

    Maruoka, H.

    1981-07-28

    Electrostatically charged liquid fuel is introduced into a venturi to be atomized therein and is then applied to the combustion chamber of an engine under the control of electrostatic force for properly controlling the air-fuel mixture ratio.

  8. Air-fuel mixture ratio control using electrostatic force

    SciTech Connect

    Maruoka, H.

    1980-01-15

    Electrostatically charged liquid fuel is introduced into a venturi to be atomized therein and is then applied to the combustion chambers of an engine under the control of electrostatic force for properly controlling the air-fuel mixture ratio.

  9. Inorganic salt mixtures as electrolyte media in fuel cells

    NASA Technical Reports Server (NTRS)

    Angell, Charles Austen (Inventor); Belieres, Jean-Philippe (Inventor); Francis-Gervasio, Dominic (Inventor)

    2012-01-01

    Fuel cell designs and techniques for converting chemical energy into electrical energy uses a fuel cell are disclosed. The designs and techniques include an anode to receive fuel, a cathode to receive oxygen, and an electrolyte chamber in the fuel cell, including an electrolyte medium, where the electrolyte medium includes an inorganic salt mixture in the fuel cell. The salt mixture includes pre-determined quantities of at least two salts chosen from a group consisting of ammonium trifluoromethanesulfonate, ammonium trifluoroacetate, and ammonium nitrate, to conduct charge from the anode to the cathode. The fuel cell includes an electrical circuit operatively coupled to the fuel cell to transport electrons from the cathode.

  10. Additive for otto cycle engines and fuel mixture so obtained

    SciTech Connect

    Scifoni, M.

    1985-02-12

    The additive for Otto cycle engines according to the present invention consists of a mixture of water, ethanol, methanol and butanol to which is added a determined quantity of a liquid obtained by pressing prickly pear leaves. Added in a small percentage to the fuel, gasoline, LP or methane, this additive prevents the oxidation associated with the use of water and/or alcohols in Otto cycle engines, lowers fuel consumption and allows the use of low octane fuel.

  11. The use of gaseous fuels mixtures for SI engines propulsion

    NASA Astrophysics Data System (ADS)

    Flekiewicz, M.; Kubica, G.

    2016-09-01

    Paper presents results of SI engine tests, carried on for different gaseous fuels. Carried out analysis made it possible to define correlation between fuel composition and engine operating parameters. Tests covered various gaseous mixtures: of methane and hydrogen and LPG with DME featuring different shares. The first group, considered as low carbon content fuels can be characterized by low CO2 emissions. Flammability of hydrogen added in those mixtures realizes the function of combustion process activator. That is why hydrogen addition improves the energy conversion by about 3%. The second group of fuels is constituted by LPG and DME mixtures. DME mixes perfectly with LPG, and differently than in case of other hydrocarbon fuels consists also of oxygen makes the stoichiometric mixture less oxygen demanding. In case of this fuel an improvement in engine volumetric and overall engine efficiency has been noticed, when compared to LPG. For the 11% DME share in the mixture an improvement of 2% in the efficiency has been noticed. During the tests standard CNG/LPG feeding systems have been used, what underlines utility value of the research. The stand tests results have been followed by combustion process simulation including exhaust forming and charge exchange.

  12. Catalytic oxidation of very fuel rich mixtures

    NASA Technical Reports Server (NTRS)

    Brabbs, T. A.

    1983-01-01

    The objective of this research is to demonstrate the feasibility of using a catalytic reactor as a tool to study soot formation from the fuel rich side of the soot limit (null set = 3 - 6). The experimental approach to be taken in the first phase of the research is to document that a hydrocarbon fuel can be burnt at very rich equivalence ratios without forming soot. A simple mono-component fuel, iso-octane, will be used as the test fuel. To insure that combustion is uniform across the catalyst bed, measurements will be made of the fuel-air equivalence ratio profile across the inlet and the temperature and product distribution across the outlet. Phase Two will be to use this environment as a testing ground for determining the effect the structure of a hydrocarbon fuel has on its tendency to form soot. Various amounts of organic compounds such as benzene will be added to the iso-octane and the reaction products studied. Other compounds to be tested will xylene, toluene, and naphthalene.

  13. Spontaneous ignition delay characteristics of hydrocarbon fuel-air mixtures

    NASA Technical Reports Server (NTRS)

    Lefebvre, A. H.; Freeman, W. G.; Cowell, L. H.

    1986-01-01

    The influence of pressure on the autoignition characteristics of homogeneous mixtures of hydrocarbon fuels in air is examined. Autoignition delay times are measured for propane, ethylene, methane, and acetylene in a continuous flow apparatus featuring a multi-point fuel injector. Results are presented for mixture temperatures from 670K to 1020K, pressures from 1 to 10 atmospheres, equivalence ratios from 0.2 to 0.7, and velocities from 5 to 30 m/s. Delay time is related to pressure, temperature, and fuel concentration by global reaction theory. The results show variations in global activation energy from 25 to 38 kcal/kg-mol, pressure exponents from 0.66 to 1.21, and fuel concentration exponents from 0.19 to 0.75 for the fuels studied. These results are generally in good agreement with previous studies carried out under similar conditions.

  14. Fuel moisture content enhances nonadditive effects of plant mixtures on flammability and fire behavior.

    PubMed

    Blauw, Luke G; Wensink, Niki; Bakker, Lisette; van Logtestijn, Richard S P; Aerts, Rien; Soudzilovskaia, Nadejda A; Cornelissen, J Hans C

    2015-09-01

    Fire behavior of plant mixtures includes a complex set of processes for which the interactive contributions of its drivers, such as plant identity and moisture, have not yet been unraveled fully. Plant flammability parameters of species mixtures can show substantial deviations of fire properties from those expected based on the component species when burnt alone; that is, there are nonadditive mixture effects. Here, we investigated how fuel moisture content affects nonadditive effects in fire behavior. We hypothesized that both the magnitude and variance of nonadditivity in flammability parameters are greater in moist than in dry fuel beds. We conducted a series of experimental burns in monocultures and 2-species mixtures with two ericaceous dwarf shrubs and two bryophyte species from temperate fire-prone heathlands. For a set of fire behavior parameters, we found that magnitude and variability of nonadditive effects are, on average, respectively 5.8 and 1.8 times larger in moist (30% MC) species mixtures compared to dry (10% MC) mixed fuel beds. In general, the moist mixtures caused negative nonadditive effects, but due to the larger variability these mixtures occasionally caused large positive nonadditive effects, while this did not occur in dry mixtures. Thus, at moister conditions, mixtures occasionally pass the moisture threshold for ignition and fire spread, which the monospecific fuel beds are unable to pass. We also show that the magnitude of nonadditivity is highly species dependent. Thus, contrary to common belief, the strong nonadditive effects in mixtures can cause higher fire occurrence at moister conditions. This new integration of surface fuel moisture and species interactions will help us to better understand fire behavior in the complexity of natural ecosystems. PMID:26380709

  15. Fuel moisture content enhances nonadditive effects of plant mixtures on flammability and fire behavior

    PubMed Central

    Blauw, Luke G; Wensink, Niki; Bakker, Lisette; van Logtestijn, Richard S P; Aerts, Rien; Soudzilovskaia, Nadejda A; Cornelissen, J Hans C

    2015-01-01

    Fire behavior of plant mixtures includes a complex set of processes for which the interactive contributions of its drivers, such as plant identity and moisture, have not yet been unraveled fully. Plant flammability parameters of species mixtures can show substantial deviations of fire properties from those expected based on the component species when burnt alone; that is, there are nonadditive mixture effects. Here, we investigated how fuel moisture content affects nonadditive effects in fire behavior. We hypothesized that both the magnitude and variance of nonadditivity in flammability parameters are greater in moist than in dry fuel beds. We conducted a series of experimental burns in monocultures and 2-species mixtures with two ericaceous dwarf shrubs and two bryophyte species from temperate fire-prone heathlands. For a set of fire behavior parameters, we found that magnitude and variability of nonadditive effects are, on average, respectively 5.8 and 1.8 times larger in moist (30% MC) species mixtures compared to dry (10% MC) mixed fuel beds. In general, the moist mixtures caused negative nonadditive effects, but due to the larger variability these mixtures occasionally caused large positive nonadditive effects, while this did not occur in dry mixtures. Thus, at moister conditions, mixtures occasionally pass the moisture threshold for ignition and fire spread, which the monospecific fuel beds are unable to pass. We also show that the magnitude of nonadditivity is highly species dependent. Thus, contrary to common belief, the strong nonadditive effects in mixtures can cause higher fire occurrence at moister conditions. This new integration of surface fuel moisture and species interactions will help us to better understand fire behavior in the complexity of natural ecosystems. PMID:26380709

  16. Fuel moisture content enhances nonadditive effects of plant mixtures on flammability and fire behavior.

    PubMed

    Blauw, Luke G; Wensink, Niki; Bakker, Lisette; van Logtestijn, Richard S P; Aerts, Rien; Soudzilovskaia, Nadejda A; Cornelissen, J Hans C

    2015-09-01

    Fire behavior of plant mixtures includes a complex set of processes for which the interactive contributions of its drivers, such as plant identity and moisture, have not yet been unraveled fully. Plant flammability parameters of species mixtures can show substantial deviations of fire properties from those expected based on the component species when burnt alone; that is, there are nonadditive mixture effects. Here, we investigated how fuel moisture content affects nonadditive effects in fire behavior. We hypothesized that both the magnitude and variance of nonadditivity in flammability parameters are greater in moist than in dry fuel beds. We conducted a series of experimental burns in monocultures and 2-species mixtures with two ericaceous dwarf shrubs and two bryophyte species from temperate fire-prone heathlands. For a set of fire behavior parameters, we found that magnitude and variability of nonadditive effects are, on average, respectively 5.8 and 1.8 times larger in moist (30% MC) species mixtures compared to dry (10% MC) mixed fuel beds. In general, the moist mixtures caused negative nonadditive effects, but due to the larger variability these mixtures occasionally caused large positive nonadditive effects, while this did not occur in dry mixtures. Thus, at moister conditions, mixtures occasionally pass the moisture threshold for ignition and fire spread, which the monospecific fuel beds are unable to pass. We also show that the magnitude of nonadditivity is highly species dependent. Thus, contrary to common belief, the strong nonadditive effects in mixtures can cause higher fire occurrence at moister conditions. This new integration of surface fuel moisture and species interactions will help us to better understand fire behavior in the complexity of natural ecosystems.

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

    SciTech Connect

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

    1981-03-26

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

  18. Flame propagation in heterogeneous mixtures of fuel drops and air

    NASA Technical Reports Server (NTRS)

    Myers, G. D.; Lefebvre, A. H.

    1984-01-01

    Photographic methods are used to measure flame speeds in flowing mixtures of fuel props and air at atmospheric pressure. The fuels employed include a conventional fuel oil plus various blends JP 7 with stocks containing single-ring and mullti-ring aromatics. The results for stoichiometric mixtures show that flame propagation cannot occur in mixtures containing mean drop sizes larger than 300 to 400 microns, depending on the fuel type. For smaller drop sizes, down to around 60 microns, flame speed is inversely proportional to drop size, indicating that evaporation rates are limiting to flame speed. Below around 60 microns, the curves of flame speed versus mean drop size flatten out, thereby demonstrating that for finely atomized sprays flame speeds are much less dependent on evaporation rates, and are governed primarily by mixing and/or chemical reaction rates. The fuels exhibiting the highest flame speeds are those containing multi-ring aromatics. This is attributed to the higher radiative heat flux emanating from their soot-bearing flames which enhances the rate of evaporation of the fuel drops approaching the flame front.

  19. Comparative exergy analysis of direct alcohol fuel cells using fuel mixtures

    NASA Astrophysics Data System (ADS)

    Leo, Teresa J.; Raso, Miguel A.; Navarro, Emilio; Sánchez-de-la-Blanca, Emilia

    Within the last years there has been increasing interest in direct liquid fuel cells as power sources for portable devices and, in the future, power plants for electric vehicles and other transport media as ships will join those applications. Methanol is considerably more convenient and easy to use than gaseous hydrogen and a considerable work is devoted to the development of direct methanol fuel cells. But ethanol has much lower toxicity and from an ecological viewpoint ethanol is exceptional among all other types of fuel as is the only chemical fuel in renewable supply. The aim of this study is to investigate the possibility of using direct alcohol fuel cells fed with alcohol mixtures. For this purpose, a comparative exergy analysis of a direct alcohol fuel cell fed with alcohol mixtures against the same fuel cell fed with single alcohols is performed. The exergetic efficiency and the exergy loss and destruction are calculated and compared in each case. When alcohol mixtures are fed to the fuel cell, the contribution of each fuel to the fuel cell performance is weighted attending to their relative proportion in the aqueous solution. The optimum alcohol composition for methanol/ethanol mixtures has been determined.

  20. Isentropic Compression of Multicomponent Mixtures of Fuels and Inert Gases

    NASA Technical Reports Server (NTRS)

    Barragan, Michelle; Julien, Howard L.; Woods, Stephen S.; Wilson, D. Bruce; Saulsberry, Regor L.

    2000-01-01

    In selected aerospace applications of the fuels hydrazine and monomethythydrazine, there occur conditions which can result in the isentropic compression of a multicomponent mixture of fuel and inert gas. One such example is when a driver gas such as helium comes out of solution and mixes with the fuel vapor, which is being compressed. A second example is when product gas from an energetic device mixes with the fuel vapor which is being compressed. Thermodynamic analysis has shown that under isentropic compression, the fuels hydrazine and monomethylhydrazine must be treated as real fluids using appropriate equations of state. The appropriate equations of state are the Peng-Robinson equation of state for hydrazine and the Redlich-Kwong-Soave equation of state for monomethylhydrazine. The addition of an inert gas of variable quantity and input temperature and pressure to the fuel compounds the problem for safety design or analysis. This work provides the appropriate thermodynamic analysis of isentropic compression of the two examples cited. In addition to an entropy balance describing the change of state, an enthalpy balance is required. The presence of multicomponents in the system requires that appropriate mixing rules are identified and applied to the analysis. This analysis is not currently available.

  1. Method and apparatus for controlling fuel/air mixture in a lean burn engine

    DOEpatents

    Kubesh, John Thomas; Dodge, Lee Gene; Podnar, Daniel James

    1998-04-07

    The system for controlling the fuel/air mixture supplied to a lean burn engine when operating on natural gas, gasoline, hydrogen, alcohol, propane, butane, diesel or any other fuel as desired. As specific humidity of air supplied to the lean burn engine increases, the oxygen concentration of exhaust gas discharged by the engine for a given equivalence ratio will decrease. Closed loop fuel control systems typically attempt to maintain a constant exhaust gas oxygen concentration. Therefore, the decrease in the exhaust gas oxygen concentration resulting from increased specific humidity will often be improperly attributed to an excessive supply of fuel and the control system will incorrectly reduce the amount of fuel supplied to the engine. Also, the minimum fuel/air equivalence ratio for a lean burn engine to avoid misfiring will increase as specific humidity increases. A relative humidity sensor to allow the control system to provide a more enriched fuel/air mixture at high specific humidity levels. The level of specific humidity may be used to compensate an output signal from a universal exhaust gas oxygen sensor for changing oxygen concentrations at a desired equivalence ratio due to variation in specific humidity specific humidity. As a result, the control system will maintain the desired efficiency, low exhaust emissions and power level for the associated lean burn engine regardless of the specific humidity level of intake air supplied to the lean burn engine.

  2. Apparatus and method for burning a lean, premixed fuel/air mixture with low NOx emission

    DOEpatents

    Kostiuk, Larry W.; Cheng, Robert K.

    1996-01-01

    An apparatus for enabling a burner to stably burn a lean fuel/air mixture. The burner directs the lean fuel/air mixture in a stream. The apparatus comprises an annular flame stabilizer; and a device for mounting the flame stabilizer in the fuel/air mixture stream. The burner may include a body having an internal bore, in which case, the annular flame stabilizer is shaped to conform to the cross-sectional shape of the bore, is spaced from the bore by a distance greater than about 0.5 mm, and the mounting device mounts the flame stabilizer in the bore. An apparatus for burning a gaseous fuel with low NOx emissions comprises a device for premixing air with the fuel to provide a lean fuel/air mixture; a nozzle having an internal bore through which the lean fuel/air mixture passes in a stream; and a flame stabilizer mounted in the stream of the lean fuel/air mixture. The flame stabilizer may be mounted in the internal bore, in which case, it is shaped and is spaced from the bore as just described. In a method of burning a lean fuel/air mixture, a lean fuel/air mixture is provided, and is directed in a stream; an annular eddy is created in the stream of the lean fuel/air mixture; and the lean fuel/air mixture is ignited at the eddy.

  3. Ignition strategies for fuel mixtures in catalytic microburners

    NASA Astrophysics Data System (ADS)

    Seshadri, Vikram; Kaisare, Niket S.

    2010-03-01

    Ignition of methane-air and propane-air mixtures over platinum catalyst in a parallel-plate microburner is studied numerically and a comparison of their ignition characteristics is presented. The ignition behaviour of the two fuels is compared for the case of heated feed and the strategy of using propane-methane mixed fuel is analysed. We show that adding small quantities of propane reduces the ignition temperature of lean methane-air mixture. Transient response of the mixed methane-propane fuel reveals sequential ignition of propane followed by methane. Sensitivity analysis on physical properties of methane and propane shows that the higher apparent activation energy of methane combustion accounts for most of the observed differences in their ignition behaviour. Ignition by resistive preheating, specifically the effect of locally preheating initial section of the burner is investigated. The amount of electric power required for ignition decreases with decrease in the electrical preheating length. This reduction in ignition power is especially significant for low conductivity walls, compared to highly conducting walls. Finally, the gap size of the channel has a relatively small effect on ignition in catalytic microburners.

  4. Replacing equipment due to obsolescence, fuel efficiency

    SciTech Connect

    Harbor, V.

    1982-08-23

    Southern Natural Gas' engine replacement program with regard to expansion problems, replacement justification, meeting requirements (e.g. FERC regulations), economics, and removal and replacement was examined. As a result of replacement, gas supplies are more plentiful; and due to increased load factors, the replacing of four 1,300-hp units is now under way.

  5. Electrochemical cell apparatus having axially distributed entry of a fuel-spent fuel mixture transverse to the cell lengths

    DOEpatents

    Reichner, P.; Dollard, W.J.

    1991-01-08

    An electrochemical apparatus is made having a generator section containing axially elongated electrochemical cells, a fresh gaseous feed fuel inlet, a gaseous feed oxidant inlet, and at least one gaseous spent fuel exit channel, where the spent fuel exit channel passes from the generator chamber to combine with the fresh feed fuel inlet at a mixing apparatus, reformable fuel mixture channel passes through the length of the generator chamber and connects with the mixing apparatus, that channel containing entry ports within the generator chamber, where the axis of the ports is transverse to the fuel electrode surfaces, where a catalytic reforming material is distributed near the reformable fuel mixture entry ports. 2 figures.

  6. Determining size of drops in fuel mixture of internal combustion engines

    NASA Technical Reports Server (NTRS)

    Sauter, J

    1926-01-01

    In compressorless Diesel engines and in explosion engines using fuels with high boiling points it is difficult to effect a good combustion of the fuel mixture. This report presents different methods for calculating the size and uniformity of fuel droplets and mixtures.

  7. Laser-induced breakdown emission in hydrocarbon fuel mixtures

    NASA Astrophysics Data System (ADS)

    Kobayashi, Kazunobu; Bak, Moon Soo; Tanaka, Hiroki; Carter, Campbell; Do, Hyungrok

    2016-04-01

    Time-resolved emission measurements of laser-induced breakdown plasmas have been carried out to investigate the effect that gas species might have on the kinetics, particularly in excited states, and the resulting plasma properties. For this purpose, fuel-oxygen (O2)-carbon dioxide (CO2) mixtures with either helium (He) or nitrogen (N2) balance are prepared while maintaining their atomic compositions. The fuels tested in this study are methane (CH4), ethylene (C2H4), propane (C3H8), and butane (C4H10). The breakdown is produced in the mixtures (CH4/CO2/O2/He, C2H4/O2/He, C3H8/CO2/O2/He and C4H10/CO2/O2/He or CH4/CO2/O2/N2, C2H4/O2/N2, C3H8/CO2/O2/N2 and C4H10/CO2/O2/N2) at room conditions using the second harmonic of a Q-switched Nd:YAG laser (with pulse duration of 10 ns). The temporal evolution of plasma temperature is deduced from the ratio of two oxygen lines (777 nm and 823 nm) through Boltzmann analysis, while the evolution of electron number density is estimated based on Stark broadening of the Balmer-alpha (H α ) line at 656 nm and the measured plasma temperature. From the results, the temporal evolution of emission spectra and decay rates of atomic line-intensities are found to be almost identical between the breakdown plasma in the different mixtures given balancing gases. Furthermore, the temporal evolution of plasma temperature and electron number density are also found to be independent of the species compositions. Therefore, this behavior—of the breakdown emissions and plasma properties in the different mixtures with identical atomic composition—may be because the breakdown gases reach similar thermodynamic and physiochemical states immediately after the breakdown.

  8. Method and apparatus for varying the fuel ratio of an air-fuel mixture

    SciTech Connect

    Leonardi, S.

    1981-03-24

    A method and apparatus is described for varying the fuel ratio of an air-fuel mixture supplied to the carburetor of an internal combustion engine. In a first embodiment, a valve opens and closes a port in an aluminum block between a passage coupled to the pcv and carburetor and a second passage open to the atmosphere. A spring in the second passage modulates the air flow as a function of vacuum pressure and thermally responsive means maintains the valve closed until the engine reaches its operating temperature. In a second embodiment the valve is opened as a function of the wind pressure produced during vehicle movement.

  9. Turbulent Burning Velocities of Two-Component Fuel Mixtures of Methane, Propane and Hydrogen

    NASA Astrophysics Data System (ADS)

    Kido, Hiroyuki; Nakahara, Masaya; Hashimoto, Jun; Barat, Dilmurat

    In order to clarify the turbulent burning velocity of multi-component fuel mixtures, both lean and rich two-component fuel mixtures, in which methane, propane and hydrogen were used as fuels, were prepared while maintaining the laminar burning velocity approximately constant. A distinct difference in the measured turbulent burning velocity at the same turbulence intensity is observed for two-component fuel mixtures having different addition rates of fuel, even the laminar burning velocities are approximately the same. The burning velocities of lean mixtures change almost constantly as the rate of addition changes, whereas the burning velocities of the rich mixtures show no such tendency. This trend can be explained qualitatively based on the mean local burning velocity, which is estimated by taking into account the preferential diffusion effect for each fuel component. In addition, a model of turbulent burning velocity proposed for single-component fuel mixtures may be applied to two-component fuel mixtures by considering the estimated mean local burning velocity of each fuel.

  10. Bragg diffraction for normal and obliquely circularly polarized light due a new chiral mixture

    NASA Astrophysics Data System (ADS)

    Castro-Garay, P.; Manzanares-Martinez, J.; Corella-Madueño, A.; Rosas-Burgos, A.; Lizola, Josue; Clark, Marielena; Palma, Lillian

    2015-09-01

    We have found experimentally the transmittance of normal incident circularly polarized light due to new chiral mixture that was distorted by electric field. The chiral mixture was achieved by mixtures of two nematic liquid crystals (5OCB and 5CB) and S-1-bromo-2-methylbutane. We have found a regime of circular Bragg diffraction for certain values of concentrations and thickness. Optical diffraction phenomenon have received particular attention in research for optical and electro-optical applications, such as low -voltage modulators, reflective phase gratings and smart reflectors.

  11. The quantification of mixture stoichiometry when fuel molecules contain oxidizer elements or oxidizer molecules contain fuel elements.

    SciTech Connect

    Mueller, Charles J.

    2005-05-01

    The accurate quantification and control of mixture stoichiometry is critical in many applications using new combustion strategies and fuels (e.g., homogeneous charge compression ignition, gasoline direct injection, and oxygenated fuels). The parameter typically used to quantify mixture stoichiometry (i.e., the proximity of a reactant mixture to its stoichiometric condition) is the equivalence ratio, /gf. The traditional definition of /gf is based on the relative amounts of fuel and oxidizer molecules in a mixture. This definition provides an accurate measure of mixture stoichiometry when the fuel molecule does not contain oxidizer elements and when the oxidizer molecule does not contain fuel elements. However, the traditional definition of /gf leads to problems when the fuel molecule contains an oxidizer element, as is the case when an oxygenated fuel is used, or once reactions have started and the fuel has begun to oxidize. The problems arise because an oxidizer element in a fuel molecule is counted as part of the fuel, even though it acts as an oxidizer. Similarly, if an oxidizer molecule contains fuel elements, the fuel elements in the oxidizer molecule are misleadingly lumped in with the oxidizer in the traditional definition of /gf. In either case, use of the traditional definition of /gf to quantify the mixture stoichiometry can lead to significant errors. This paper introduces the oxygen equivalence ratio, /gf/gV, a parameter that properly characterizes the instantaneous mixture stoichiometry for a broader class of reactant mixtures than does /gf. Because it is an instantaneous measure of mixture stoichiometry,/gf/gV can be used to track the time-evolution of stoichiometry as a reaction progresses. The relationship between /gf/gV and /gf is shown. Errors are involved when the traditional definition of /gf is used as a measure of mixture stoichiometry with fuels that contain oxidizer elements or oxidizers that contain fuel elements; /gf/gV is used to quantify

  12. Electrochemical cell apparatus having axially distributed entry of a fuel-spent fuel mixture transverse to the cell lengths

    DOEpatents

    Reichner, Philip; Dollard, Walter J.

    1991-01-01

    An electrochemical apparatus (10) is made having a generator section (22) containing axially elongated electrochemical cells (16), a fresh gaseous feed fuel inlet (28), a gaseous feed oxidant inlet (30), and at least one gaseous spent fuel exit channel (46), where the spent fuel exit channel (46) passes from the generator chamber (22) to combine with the fresh feed fuel inlet (28) at a mixing apparatus (50), reformable fuel mixture channel (52) passes through the length of the generator chamber (22) and connects with the mixing apparatus (50), that channel containing entry ports (54) within the generator chamber (22), where the axis of the ports is transverse to the fuel electrode surfaces (18), where a catalytic reforming material is distributed near the reformable fuel mixture entry ports (54).

  13. Apparatus and method for operating internal combustion engines from variable mixtures of gaseous fuels

    SciTech Connect

    Heffel, James W.; Scott, Paul B.; Park, Chan Seung

    2011-11-01

    An apparatus and method for utilizing any arbitrary mixture ratio of multiple fuel gases having differing combustion characteristics, such as natural gas and hydrogen gas, within an internal combustion engine. The gaseous fuel composition ratio is first sensed, such as by thermal conductivity, infrared signature, sound propagation speed, or equivalent mixture differentiation mechanisms and combinations thereof which are utilized as input(s) to a "multiple map" engine control module which modulates selected operating parameters of the engine, such as fuel injection and ignition timing, in response to the proportions of fuel gases available so that the engine operates correctly and at high efficiency irrespective of the gas mixture ratio being utilized. As a result, an engine configured according to the teachings of the present invention may be fueled from at least two different fuel sources without admixing constraints.

  14. Apparatus and method for operating internal combustion engines from variable mixtures of gaseous fuels

    DOEpatents

    Heffel, James W.; Scott, Paul B.

    2003-09-02

    An apparatus and method for utilizing any arbitrary mixture ratio of multiple fuel gases having differing combustion characteristics, such as natural gas and hydrogen gas, within an internal combustion engine. The gaseous fuel composition ratio is first sensed, such as by thermal conductivity, infrared signature, sound propagation speed, or equivalent mixture differentiation mechanisms and combinations thereof which are utilized as input(s) to a "multiple map" engine control module which modulates selected operating parameters of the engine, such as fuel injection and ignition timing, in response to the proportions of fuel gases available so that the engine operates correctly and at high efficiency irrespective of the gas mixture ratio being utilized. As a result, an engine configured according to the teachings of the present invention may be fueled from at least two different fuel sources without admixing constraints.

  15. Multiple recycle of REMIX fuel based on reprocessed uranium and plutonium mixture in thermal reactors

    SciTech Connect

    Fedorov, Y.S.; Bibichev, B.A.; Zilberman, B.Y.; Baryshnikov, M.V.; Kryukov, O.V.; Khaperskaya, A.V.

    2013-07-01

    REMIX fuel consumption in WWER-1000 is considered. REMIX fuel is fabricated from non-separated mixture of uranium and plutonium obtained during NPP spent fuel reprocessing with further makeup by enriched natural uranium. It makes possible to recycle several times the total amount of uranium and plutonium obtained from spent fuel with 100% loading of the WWER-1000 core. The stored SNF could be also involved in REMIX fuel cycle by enrichment of regenerated uranium. The same approach could be applied to closing the fuel cycle of CANDU reactors. (authors)

  16. Sensor for measuring alcohol content of alcohol/gasoline fuel mixtures

    SciTech Connect

    Harris, S.J.; Swarin, S.J.; Sultan, M.F.; Lambert, D.K.; Jack, M.D.

    1993-08-31

    A sensing device is described for determining the alcohol content of an alcohol/gasoline mixture comprising: a light source emitting a light beam containing at least a first and a second wavelengths within the near-infrared spectrum, said light beam being transmitted through the alcohol/gasoline fuel mixture; means for switching the current through said light source between at least two fixed values, so as to correspondingly switch the light intensity at said first and second wavelengths which is emitted by said light source; first and second detectors which are disposed so as to receive said emitted light beam after its transmission through the alcohol/gasoline fuel mixture, said first detector determines a first amount of absorption by the alcohol/gasoline fuel mixture at said first wavelength for each of said fixed values of current, and said second detector determines a second amount of absorption by the alcohol/gasoline fuel mixture at said second wavelength for each of said fixed values of current; means for separately measuring the output voltage from said first and second detectors for each of said power settings; and computational means for determining, from said output voltages, the ratio of said first and second absorbances by the alcohol/gasoline fuel mixture at said first and said second wavelengths for each of said fixed values of current such that said ratio of absorbances provide an output indicative of the alcohol content within the alcohol/gasoline mixture.

  17. 10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... mixture of solar energy (including wind, tide, and other intermittent sources) and petroleum or natural gas, where: (1) Solar energy will account for at least 20 percent of the total annual Btu heat input... 10 Energy 4 2013-01-01 2013-01-01 false Permanent exemption for certain fuel mixtures...

  18. 10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... mixture of solar energy (including wind, tide, and other intermittent sources) and petroleum or natural gas, where: (1) Solar energy will account for at least 20 percent of the total annual Btu heat input... 10 Energy 4 2014-01-01 2014-01-01 false Permanent exemption for certain fuel mixtures...

  19. 10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... mixture of solar energy (including wind, tide, and other intermittent sources) and petroleum or natural gas, where: (1) Solar energy will account for at least 20 percent of the total annual Btu heat input... 10 Energy 4 2012-01-01 2012-01-01 false Permanent exemption for certain fuel mixtures...

  20. Compression-ignition engine performance with undoped and doped fuel oils and alcohol mixtures

    NASA Technical Reports Server (NTRS)

    Moore, Charles S; Foster, Hampton H

    1939-01-01

    Several fuel oils, doped fuel oils, and mixtures of alcohol and fuel oil were tested in a high-speed, single-cylinder, compression-ignition engine to determine power output, fuel consumption, and ignition and combustion characteristics. Fuel oils or doped fuel oils of high octane number had shorter ignition lags, lower rates of pressure rise, and gave smoother engine operation than fuel oils or doped fuel oils of low octane number. Higher engine rotative speeds and boost pressures resulted in smoother engine operation and permitted the use of fuel oils of relatively low octane number. Although the addition of a dope to a fuel oil decreased the ignition lag and the rate of pressure rise, the ensuing rate of combustion was somewhat slower than for the undoped fuel oil so that the effectiveness of combustion was practically unchanged. Alcohol used as an auxiliary fuel, either as a mixture or by separate injection, increased the rates of pressure rise and induced roughness. In general, the power output decreased as the proportion of alcohol increased and, below maximum power, varied with the heating value of the total fuel charge.

  1. The influence of oxygen concentration on the combustion of a fuel/oxidizer mixture

    SciTech Connect

    Biteau, H.; Fuentes, A.; Marlair, G.; Torero, J.L.

    2010-04-15

    The aim of the present study is to investigate the influence of the O{sub 2} concentration on the combustion behaviour of a fuel/oxidizer mixture. The material tested is a ternary mixture of lactose, starch, and potassium nitrate, which has already been used in an attempt to estimate heat release rate using the FM-Global Fire Propagation Apparatus. It provides a well-controlled combustion chamber to study the evolution of the combustion products when varying the O{sub 2} concentration, between air and low oxidizer conditions. Different chemical behaviours have been exhibited. When the O{sub 2} concentration was reduced beyond 18%, large variations were observed in the CO{sub 2} and CO concentrations. This critical O{sub 2} concentration seems to be the limit before which the material only uses its own oxidizer to react. On the other hand, mass loss did not highlight this change in chemical reactions and remained similar whatever the test conditions. This presumes that the oxidation of CO into CO{sub 2} are due to reactions occurring in the gas phase especially for large O{sub 2} concentrations. This actual behaviour can be verified using a simplified flammability limit model adapted for the current work. Finally, a sensitivity analysis has been carried out to underline the influence of CO concentration in the evaluation of heat release rate using typical calorimetric methods. The results of this study provide a critical basis for the investigation of the combustion of a fuel/oxidizer mixture and for the validation of future numerical models. (author)

  2. Stabilization of T-6 jet fuel by mixtures of antioxidants

    SciTech Connect

    Golubeva, I.A.; Gutnikova, L.P.; Popova, T.V.; Vishnyakova, T.P.

    1985-09-01

    Work has been reported on synergistic combinations of additives for the stabilization of jet fuels. This paper investigates combinations of the additive KF-1 with dilauryl thiodipropionate (DLTDP). Data on the effects of these additive combinations on the post-test optical density, acidity and peroxide number of T-6 fuel is presented. Attention is also given to combinations of antioxidants with organometallic compounds. The stabilization of T-6 fuel by combination of KF-1 with phenosansesters of 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid and pentaerythritol, diethylene glycol, ethylene glycol, and thiodiethylene glycol is investigated.

  3. Combustible coal/water mixtures for fuel and methods of preparing the same

    SciTech Connect

    Sawyer, E.W. Jr.

    1984-02-21

    A novel fuel slurry is claimed comprising a mixture of finely ground coal constituting 65 to 70 percent of the fuel, water, a wetting/dispersing agent for the coal constituting 0.5 to 5 percent of the fuel and for stabilizing the fuel slurry a suspending agent which is a clay such as attapulgite clay in the dry, pregelled or predispersed form. Other clays can be montmorillonate clay. If the coal slurry is to be used immediately the clay or other gelling agent is not necessary to maintain suspension stability.

  4. [Fire disaster due to deflagration of a propane gas-air mixture].

    PubMed

    Nadjem, Hadi; Vogt, Susanne; Simon, Karl-Heinz; Pollak, Stefan; Geisenberger, Dorothee; Kramer, Lena; Pircher, Rebecca; Perdekampl, Markus Große; Thierauf-Emberger, Annette

    2015-01-01

    On 26 Nov 2012, a serious fire occurred at Neustadt/Black Forest in which 14 persons in a sheltered workshop died and 10 other individuals were injured. The fire was caused by the unbridled escape of propane gas due to accidental disconnection of the screw fixing between a gas bottle and a catalytic heater. Deflagration of the propane gas-air mixture set the workshop facilities on fire. In spite of partly extensive burns the fatally injured victims could be rapidly identified. The results of the fire investigations at the scene and the autopsy findings are presented. Carboxyhemoglobin concentrations ranged between 8 and 56 % and signs of fire fume inhalation were present in all cases. Three victims had eardrum ruptures due to the sudden increase in air pressure during the deflagration. PMID:26548032

  5. [Fire disaster due to deflagration of a propane gas-air mixture].

    PubMed

    Nadjem, Hadi; Vogt, Susanne; Simon, Karl-Heinz; Pollak, Stefan; Geisenberger, Dorothee; Kramer, Lena; Pircher, Rebecca; Perdekampl, Markus Große; Thierauf-Emberger, Annette

    2015-01-01

    On 26 Nov 2012, a serious fire occurred at Neustadt/Black Forest in which 14 persons in a sheltered workshop died and 10 other individuals were injured. The fire was caused by the unbridled escape of propane gas due to accidental disconnection of the screw fixing between a gas bottle and a catalytic heater. Deflagration of the propane gas-air mixture set the workshop facilities on fire. In spite of partly extensive burns the fatally injured victims could be rapidly identified. The results of the fire investigations at the scene and the autopsy findings are presented. Carboxyhemoglobin concentrations ranged between 8 and 56 % and signs of fire fume inhalation were present in all cases. Three victims had eardrum ruptures due to the sudden increase in air pressure during the deflagration.

  6. On-Line Measurement of Heat of Combustion of Gaseous Hydrocarbon Fuel Mixtures

    NASA Technical Reports Server (NTRS)

    Sprinkle, Danny R.; Chaturvedi, Sushil K.; Kheireddine, Ali

    1996-01-01

    A method for the on-line measurement of the heat of combustion of gaseous hydrocarbon fuel mixtures has been developed and tested. The method involves combustion of a test gas with a measured quantity of air to achieve a preset concentration of oxygen in the combustion products. This method involves using a controller which maintains the fuel (gas) volumetric flow rate at a level consistent with the desired oxygen concentration in the combustion products. The heat of combustion is determined form a known correlation with the fuel flow rate. An on-line computer accesses the fuel flow data and displays the heat of combustion measurement at desired time intervals. This technique appears to be especially applicable for measuring heats of combustion of hydrocarbon mixtures of unknown composition such as natural gas.

  7. The Oxygen Ratio: A Fuel-Independent Measure of Mixture Stoichiometry

    SciTech Connect

    Mueller, C J; Musculus, M P; Pickett, L M; Pitz, W J; Westbrook, C K

    2003-12-19

    The pollutant-formation characteristics and other properties of a combustion reaction typically depend strongly on the proximity of the mixture to its stoichiometric condition, i.e., the ''mixture stoichiometry.'' A quantitative, widely applicable measure of this mixture property is therefore a critical independent variable in the study of combustion systems. Such a parameter enables the clear separation of mixture stoichiometry effects from other effects (e.g., fuel molecular structure, product temperature, diluent concentration, pressure). The parameter most often used to quantify mixture stoichiometry is the equivalence ratio. Unfortunately, the equivalence ratio fails to properly account for oxygen in oxygenates, i.e., compounds that have oxygen chemically bound within the fuel molecule. This manuscript introduces the oxygen ratio, a parameter that properly characterizes mixture stoichiometry for a broader class of reactants than does the equivalence ratio, including oxygenates. A detailed definition of the oxygen ratio is provided and used to show its relationship to the equivalence ratio. The definition is also used to quantify errors involved when the equivalence ratio is used as a measure of mixture stoichiometry with oxygenates. Proper usage of the oxygen ratio is discussed and the oxygen ratio is used to interpret results in a practical example.

  8. Ways of solving environmental problems while transferring the boilers for burning water-bitumen mixture instead of fuel oil

    NASA Astrophysics Data System (ADS)

    Kotler, V. R.; Sosin, D. V.

    2009-03-01

    Information concerning a new kind (for Russia) of liquid fuel, i.e., water-bitumen mixture (orimulsion), is presented. The application of the new fuel instead of the fuel oil at a boiler of a power unit of 350-MW capacity makes it possible to decrease sufficiently the expenditures for fuel while keeping the main environmental indices.

  9. Suppression of turbulent energy cascade due to phase separation in homogenous binary mixture fluid

    NASA Astrophysics Data System (ADS)

    Takagi, Youhei; Okamoto, Sachiya

    2015-11-01

    When a multi-component fluid mixture becomes themophysically unstable state by quenching from well-melting condition, phase separation due to spinodal decomposition occurs, and a self-organized structure is formed. During phase separation, free energy is consumed for the structure formation. In our previous report, the phase separation in homogenous turbulence was numerically simulated and the coarsening process of phase separation was discussed. In this study, we extended our numerical model to a high Schmidt number fluid corresponding to actual polymer solution. The governing equations were continuity, Navier-Stokes, and Chan-Hiliard equations as same as our previous report. The flow filed was an isotropic homogenous turbulence, and the dimensionless parameters in the Chan-Hilliard equation were estimated based on the thermophysical condition of binary mixture. From the numerical results, it was found that turbulent energy cascade was drastically suppressed in the inertial subrange by phase separation for the high Schmidt number flow. By using the identification of turbulent and phase separation structure, we discussed the relation between total energy balance and the structures formation processes. This study is financially supported by the Grand-in-Aid for Young Scientists (B) (No. T26820045) from the Ministry of Education, Cul-ture, Sports, Science and Technology of Japan.

  10. An Experimental Investigation of Hypergolic Ignition Delay of Hydrogen Peroxide with Fuel Mixtures

    NASA Technical Reports Server (NTRS)

    Blevins, John A.; Gostowski, Rudy; Chianese, Silvio

    2003-01-01

    An experimental evaluation of decomposition and ignition delay of hydrogen peroxide at concentrations of 80% to 98% with combinations of hydrocarbon fuels, tertiary amines and transition metal chelates will be presented in the proposed paper. The results will be compared to hydrazine ignition delays with hydrogen peroxide and nitric acid mixtures using the same test apparatus.

  11. Fuel and lubricant additives from acid treated mixtures of vegetable oil derived amides and esters

    SciTech Connect

    Bonazza, B.R.; Devault, A.N.

    1981-05-26

    Vegetable oils such as corn oil, peanut oil, and soy oil are reacted with polyamines to form a mixture containing amides, imides, half esters, and glycerol with subsequent treatment with a strong acid such as sulfonic acid to produce a product mix that has good detergent properties in fuels and lubricants.

  12. RECORDING FLAME SPEED DATA OF FUEL AND AIR RATIO MIXTURES - THE HORIZONTAL GLASS TUBE IS FILLED WITH

    NASA Technical Reports Server (NTRS)

    1949-01-01

    RECORDING FLAME SPEED DATA OF FUEL AND AIR RATIO MIXTURES - THE HORIZONTAL GLASS TUBE IS FILLED WITH A HOMOGENOUS MIXTURE OF FUEL AND AIR - THE RATE OF FLAME TRAVEL IS PICKED UP BY PHOTO CELLS SHOWN ABOVE THE TUBE AND RECORDED ON THE ELECTRONIC TIME

  13. PEM fuel cell stack performance using dilute hydrogen mixture. Implications on electrochemical engine system performance and design

    SciTech Connect

    Inbody, M.A.; Vanderborgh, N.E.; Hedstrom, J.C.; Tafoya, J.I.

    1996-12-31

    Onboard fuel processing to generate a hydrogen-rich fuel for PEM fuel cells is being considered as an alternative to stored hydrogen fuel for transportation applications. If successful, this approach, contrasted to operating with onboard hydrogen, utilizes the existing fuels infrastructure and provides required vehicle range. One attractive, commercial liquid fuels option is steam reforming of methanol. However, expanding the liquid methanol infrastructure will take both time and capital. Consequently technology is also being developed to utilize existing transportation fuels, such as gasoline or diesel, to power PEM fuel cell systems. Steam reforming of methanol generates a mixture with a dry gas composition of 75% hydrogen and 25% carbon dioxide. Steam reforming, autothermal reforming, and partial oxidation reforming of C{sub 2} and larger hydrocarbons produces a mixture with a more dilute hydrogen concentration (65%-40%) along with carbon dioxide ({approx}20%) and nitrogen ({approx}10%-40%). Performance of PEM fuel cell stacks on these dilute hydrogen mixtures will affect the overall electrochemical engine system design as well as the overall efficiency. The Los Alamos Fuel Cell Stack Test facility was used to access the performance of a PEM Fuel cell stack over the range of gas compositions chosen to replicate anode feeds from various fuel processing options for hydrocarbon and alcohol fuels. The focus of the experiments was on the anode performance with dilute hydrogen mixtures with carbon dioxide and nitrogen diluents. Performance with other anode feed contaminants, such as carbon monoxide, are not reported here.

  14. Combustion of hydrogen-based mixtures in gas-fueled reciprocating engines

    NASA Astrophysics Data System (ADS)

    Smygalina, A. E.; Zaitchenko, V. M.; Ivanov, M. F.; Kiverin, A. D.

    2015-12-01

    The research is devoted to the possibility for application of hydrogen accumulated from renewable energy sources as a fuel for a reciprocating engine, which serves as an electrical generator drive. Hydrogen combustion in the chamber of a reciprocating engine, as a rule, occurs in a detonation mode. In order to obtain less hard modes, the present research proposes the usage of steam additions to hydrogen-air mixture or lean hydrogen-air mixtures. Mathematical simulation is used for investigation of combustion of mentioned mixtures in the combustion chamber of a reciprocating engine with a spark-plug ignition. The comparison of the usage of hydrogen-steam-air mixtures and lean hydrogen-air mixtures as fuels is given. The dependence of arising combustion modes and its quantitative characteristics on hydrogen content in combustible composition is investigated. The analysis of optimal combustion is presented, which is based on the consideration of two parameters: peak pressure in one cycle and the crankshaft angle corresponding to the achievement of the peak pressure.

  15. Preliminary Investigation of Performance and Starting Characteristics of Liquid Fluorine : Liquid Oxygen Mixtures with Jet Fuel

    NASA Technical Reports Server (NTRS)

    Rothenberg, Edward A; Ordin, Paul M

    1954-01-01

    The performance of jet fuel with an oxidant mixture containing 70 percent liquid fluorine and 30 percent liquid oxygen by weight was investigated in a 500-pound-thrust engine operating at a chamber pressure of 300 pounds per square inch absolute. A one-oxidant-on-one-fuel skewed-hole impinging-jet injector was evaluated in a chamber of characteristic length equal to 50 inches. A maximum experimental specific impulse of 268 pound-seconds per pound was obtained at 25 percent fuel, which corresponds to 96 percent of the maximum theoretical specific impulse based on frozen composition expansion. The maximum characteristic velocity obtained was 6050 feet per second at 23 percent fuel, or 94 percent of the theoretical maximum. The average thrust coefficient was 1.38 for the 500-pound thrust combustion-chamber nozzle used, which was 99 percent of the theoretical (frozen) maximum. Mixtures of fluorine and oxygen were found to be self-igniting with jet fuel with fluorine concentrations as low as 4 percent, when low starting propellant flow rated were used.

  16. The Suitability of the Fuel Mixture of Horse Manure and Bedding Materials for Combustion

    NASA Astrophysics Data System (ADS)

    Tyni, Sanna K.; Tiainen, Minna S.; Laitinen, Risto S.

    The mixture of horse manure and bedding materials (peat and sawdust) appear to be a potential biofuel. The chemical compositions of horse manure, bedding materials, and the mixture of these have been characterized by SEM-EDS and ICP-OES. In addition, the compositional distribution of ash of these materials has been determined and this facilitates the estimation of their propensity for ash-related problems in boilers. NOx and SOx emissions from the co-combustion are also discussed on the basis of the chemical composition of fuel mixtures. It seems that co-combustion of horse manure and bedding materials in FB boilers is suitable for small-scale energy production.

  17. An Experimental Investigation of Hypergolic Ignition Delay of Hydrogen Peroxide with Fuel Mixtures

    NASA Technical Reports Server (NTRS)

    Blevins, John A.; Gostowski, Rudy; Chianese, Silvio

    2003-01-01

    An experimental investigation of hypergolicity and ignition delay of fuel mixtures with hydrogen peroxide is presented. Example results of high speed photography and schleiren from drop tests are shown. Also, a discussion of the sensitivity to experimental parameters such as drop size and subsequent uncertainty considerations of ignition delay results is presented. It is shown that using the described setup on the mixtures presented, the precision uncertainty is on the order of 6% of average ignition delay and 5% of average decomposition delay. This represents sufficient repeatability for first order discrimination of ignition delay for propellant development and screening. Two mixtures, each using commonly available amines and transition metal compounds, are presented as examples that result in ignition delays on the order of 10 milliseconds.

  18. Detonation propagation through methane-air mixtures with fuel concentration gradients

    NASA Astrophysics Data System (ADS)

    Kessler, David; Gamezo, Vadim; Oran, Elaine

    2010-11-01

    The complex structure of a multidimensional detonation front consists of constantly changing, multiply intersecting incident shocks and Mach stems followed by growing and shrinking regions of reacted and unreacted gases. Because these flow structures change in time, the energy release in the shocked and compressed gases varies in space and time. Trajectories of triple points formed at shock intersections create cellular patterns whose size and structure are characteristic of the particular material and the background condition. In high-activation-energy fuel-air mixtures, such as methane in air, cellular patterns are relatively large, very irregular, and have complex and changing substructures. Here we use numerical simulations to study the behavior of detonations propagating through methane-air mixtures with a spatial gradient of fuel concentration. When the mixture stoichiometry varies from stoichiometric, the detonation propagation speed slows and sizes of cellular structures grow. In partially premixed systems with a nonuniform concentration of fuel -- a condition that can occur, for example, naturally in sealed underground coal mine tunnels -- both the propagation speed and the characteristic detonation cell size vary spatially.

  19. The Effects of Engine Speed and Mixture Temperature on the Knocking Characteristics of Several Fuels

    NASA Technical Reports Server (NTRS)

    Lee, Dana W

    1940-01-01

    Six 100-octane and two 87-octane aviation engine fuels were tested in a modified C.F.R. variable-compression engine at 1,500, 2,000 and 2,500 rpm. The mixture temperature was raised from 50 to 300 F in approximately 50 degree steps and, at each temperature, the compression ratio was adjusted to give incipient knock as shown by a cathode ray indicator. The results are presented in tabular form. The results are analyzed on the assumption that the conditions which determine whether a given fuel will knock are the maximum values of density and temperature reached by the burning gases. A maximum permissible density factor, proportional to the maximum density of the burning gases just prior to incipient knock, and the temperature of the burning gases at that time were computed for each of the test conditions. Values of the density factors were plotted against the corresponding end-gas temperatures for the three engine speeds and also against engine speed for several and end-gas temperatures. The maximum permissible density factor varied only slightly with engine speed but decreased rapidly with an increase in the end-gas temperature. The effect of changing the mixture temperature was different for fuels of different types. The results emphasize the desirability of determining the anti knock values of fuels over a wide range of engine and intake-air conditions rather that at a single set of conditions.

  20. Measurements of fuel mixture fraction oscillations of a turbulent jet non-premixed flame

    SciTech Connect

    Kanga, D.M.; Fernandez, V.; Culick, F.E.C.; Ratner, A.

    2009-01-15

    This work describes new type of combustion instability for which the 3-way coupling between mixing, flame heat release, and acoustics is modified by local buoyancy effects. Measurements of fuel mixture fraction are made for a non-premixed jet flame in a combustion chamber to assess the dynamics of mixing under imposed acoustic oscillations (22-55 Hz). Infrared laser absorption and phase resolved acetone-planar laser induced fluorescence are used to measure the fuel mixture fraction and then the degree of fuel/air mixing is calculated by determining the unmixedness. Results show acoustic excitation causes oscillations in the degree of fuel/air mixing at the driving frequency, which results in oscillatory flame behavior. This oscillatory flame behavior couples to the buoyancy and this in turn affects the mixing. Results also show that the mixing becomes less effective when the excitation frequency is increased or when the flame is present, compared to the non-reacting case. This work describes a key coupling mechanism that occurs when buoyancy is a significant factor in the flow field. (author)

  1. Effects of two diesel fuel mixtures on fecal coliform bacteria densities

    SciTech Connect

    Marcus, J.M.; Scott, G.I.

    1989-03-01

    One of the major potential environmental impacts from synthetic fuel production plants and conventional petroleum refinement operations is the spillage of the refined product into natural waters. Impacts upon aquatic ecosystems resulting from spills of synthetic fuel would likely be different from those associated with conventional petroleum since products extracted from coal or shale are generally richer in phenolics, aromatic amines and other soluble organic compounds. Also, synfuels have higher water solubilities than equivalent petroleum products giving the potential for higher water concentrations of hydrocarbons. This study tested the effects of the water soluble fractions (WSFs) of a shale diesel fuel mixture (SDFM) and a petroleum diesel fuel mixture (PDFM) on the growth of fecal coliform bacteria, the group used almost universally as an indicator of bacteriological water quality. The WSF was tested instead of whole oil because acute toxicity results primarily from this fraction. A wild group of fecal coliform bacteria was used since the objective was to observe effects upon this indicator group encountered in the environment instead of pure laboratory cultures by the routine ambient monitoring and measurement technique of membrane filter colony counts as employed by most water quality management agencies.

  2. Performance of an internal reforming molten carbonate fuel cell supplied with ethanol/water mixture

    SciTech Connect

    Freni, S.; Maggio, G.; Barone, F.

    1996-12-31

    The state of an on the field of molten carbonate fuel cell (MCFC) systems covers many technological aspects related to the use of these systems for the production of electricity. In this respect, extensive research efforts have been made to develop a technology using the methane based on the steam reforming process, and different configurations have been analyzed and their performance determined for several operative cell conditions. However, the operative temperature (T-923 K) of the MCFC. that allows the direct conversion of hydrocarbons or alcohols into H{sub 2} and CO, promotes researches in the field of alternative fuels, more easily transported and reformed compared to methane. In this paper are described the most indicative results obtained by a study that considers the use of water/ethanol mixture as an attractive alternative to the methane for a molten carbonate fuel cell.

  3. Unsteady Extinction of Opposed Jet Ethylene/Methane HIFiRE Surrogate Fuel Mixtures vs Air

    NASA Technical Reports Server (NTRS)

    Vaden, Sarah N.; Debes, Rachel L.; Lash, E. Lara; Burk, Rachel S.; Boyd, C. Merritt; Wilson, Lloyd G.; Pellett, Gerald L.

    2009-01-01

    A unique idealized study of the subject fuel vs. air systems was conducted using an Oscillatory-input Opposed Jet Burner (OOJB) system and a newly refined analysis. Extensive dynamic-extinction measurements were obtained on unanchored (free-floating) laminar Counter Flow Diffusion Flames (CFDFs) at 1-atm, stabilized by steady input velocities (e.g., U(sub air)) and perturbed by superimposed in-phase sinusoidal velocity inputs at fuel and air nozzle exits. Ethylene (C2H4) and methane (CH4), and intermediate 64/36 and 15/85 molar percent mixtures were studied. The latter gaseous surrogates were chosen earlier to mimic ignition and respective steady Flame Strengths (FS = U(sub air)) of vaporized and cracked, and un-cracked, JP-7 "like" kerosene for a Hypersonic International Flight Research Experimentation (HIFiRE) scramjet. For steady idealized flameholding, the 100% C2H4 flame is respectively approx. 1.3 and approx.2.7 times stronger than a 64/36 mix and CH4; but is still 12.0 times weaker than a 100% H2-air flame. Limited Hot-Wire (HW) measurements of velocity oscillations at convergent-nozzle exits, and more extensive Probe Microphone (PM) measurements of acoustic pressures, were used to normalize Dynamic FSs, which decayed linearly with pk/pk U(sub air) (velocity magnitude, HW), and also pk/pk P (pressure magnitude, PM). Thus Dynamic Flame Weakening (DFW) is defined as % decrease in FS per Pascal of pk/pk P oscillation, namely, DFW = -100 d(U(sub air)/U(sub air),0Hz)/d(pkpk P). Key findings are: (1) Ethylene flames are uniquely strong and resilient to extinction by oscillating inflows below 150 Hz; (2) Methane flames are uniquely weak; (3) Ethylene / methane surrogate flames are disproportionately strong with respect to ethylene content; and (4) Flame weakening is consistent with limited published results on forced unsteady CFDFs. Thus from 0 to approx. 10 Hz and slightly higher, lagging diffusive responses of key species led to progressive phase lags (relative

  4. The flammability limits of lean fuel-air mixtures: thermochemical and kinetic criteria for explosion hazards.

    PubMed

    Burgess, D; Hertzberg, M

    1975-01-01

    The present state of knowledge is reviewed concisely in terms of the experimental methods used, the effect of apparatus size, accuracy of data, methods of data presentation, and the sensitivity of the limits to initial temperature and pressure. The heat of combustion per mole of gas mixture at the lean limit is a reliable thermochemical criterion for the flammability of organic fuels with comparable reactivities. The limit calorific value for the heavy paraffins is 11.5 +/- 0.1 kcal mole -1. However, kinetic effects strongly influence this value. Highly reactive fuels (hydrogen, acetylene) require lower energy contents, whereas less reactive fuels (ammonia) require higher values. Hydrogen-starved fuels (carbon monoxide, cyanogen) show marked anomalies and are sensitive to impurities that can provide H-atom chain carriers. These kinetic effects are reflected in the experimentally measurable burning velocity of the fuel. This parameter is a key ingredient in the theory of flammable limits, which is briefly sketched. Five competing processes dissipate power from the combustion wave and quench it at some characteristic limit velocity. The prevalent consensus that the limits are controlled by natural convection is clearly demonstrated, and the complex interplay of kinetics and thermochemistry follows logically therefrom.

  5. Analysis of the possibility of fabricating compact combustion-driven DF lasers due to fuel preheating

    NASA Astrophysics Data System (ADS)

    Fang, Xiaoting; Yuan, Shengfu; Hua, Weihong

    2016-09-01

    We report a theoretical calculation of the processes proceeding in the combustor of combustion-driven cw DF/HF chemical lasers with different mixtures of fuels preheated to high temperatures. Calculation results demonstrate a great effect of the preheating temperature on the yield of F atoms and strongest deactivator, on the primary dilution ratio ψp and on the estimated specific power. When fuels are preheated to about 1300 K, the specific power is improved by about 74.2%, and the total mass of the fuel is reduced by about 43%, which makes it possible to realise a more compact and efficient design of combustion-driven cw DF/HF chemical lasers at elevated combustor pressures. Fuel preheating can facilitate the development of chemical lasers and high-power lasers based not only on airborne and space-borne platforms, but also on mobile ground-based platforms.

  6. Reductions in aircraft particulate emissions due to the use of Fischer-Tropsch fuels

    NASA Astrophysics Data System (ADS)

    Beyersdorf, A. J.; Timko, M. T.; Ziemba, L. D.; Bulzan, D.; Corporan, E.; Herndon, S. C.; Howard, R.; Miake-Lye, R.; Thornhill, K. L.; Winstead, E.; Wey, C.; Yu, Z.; Anderson, B. E.

    2013-06-01

    The use of alternative fuels for aviation is likely to increase due to concerns over fuel security, price stability and the sustainability of fuel sources. Concurrent reductions in particulate emissions from these alternative fuels are expected because of changes in fuel composition including reduced sulfur and aromatic content. The NASA Alternative Aviation Fuel Experiment (AAFEX) was conducted in January-February 2009 to investigate the effects of synthetic fuels on gas-phase and particulate emissions. Standard petroleum JP-8 fuel, pure synthetic fuels produced from natural gas and coal feedstocks using the Fischer-Tropsch (FT) process, and 50% blends of both fuels were tested in the CFM-56 engines on a DC-8 aircraft. To examine plume chemistry and particle evolution with time, samples were drawn from inlet probes positioned 1, 30, and 145 m downstream of the aircraft engines. No significant alteration to engine performance was measured when burning the alternative fuels. However, leaks in the aircraft fuel system were detected when operated with the pure FT fuels as a result of the absence of aromatic compounds in the fuel. Dramatic reductions in soot emissions were measured for both the pure FT fuels (reductions of 84% averaged over all powers) and blended fuels (64%) relative to the JP-8 baseline with the largest reductions at idle conditions. The alternative fuels also produced smaller soot (e.g. at 85% power, volume mean diameters were reduced from 78 nm for JP-8 to 51 nm for the FT fuel), which may reduce their ability to act as cloud condensation nuclei (CCN). The reductions in particulate emissions are expected for all alternative fuels with similar reductions in fuel sulfur and aromatic content regardless of the feedstock. As the plume cools downwind of the engine, nucleation-mode aerosols form. For the pure FT fuels, reductions (94% averaged over all powers) in downwind particle number emissions were similar to those measured at the exhaust plane (84

  7. Catalytic and electrochemical behaviour of solid oxide fuel cell operated with simulated-biogas mixtures

    NASA Astrophysics Data System (ADS)

    Dang-Long, T.; Quang-Tuyen, T.; Shiratori, Y.

    2016-06-01

    Being produced from organic matters of wastes (bio-wastes) through a fermentation process, biogas mainly composed of CH4 and CO2 and can be considered as a secondary energy carrier derived from solar energy. To generate electricity from biogas through the electrochemical process in fuel cells is a state-of-the-art technology possessing higher energy conversion efficiency without harmful emissions compared to combustion process in heat engines. Getting benefits from high operating temperature such as direct internal reforming ability and activation of electrochemical reactions to increase overall system efficiency, solid oxide fuel cell (SOFC) system operated with biogas becomes a promising candidate for distributed power generator for rural applications leading to reductions of environmental issues caused by greenhouse effects and bio-wastes. CO2 reforming of CH4 and electrochemical oxidation of the produced syngas (H2-CO mixture) are two main reaction processes within porous anode material of SOFC. Here catalytic and electrochemical behavior of Ni-ScSZ (scandia stabilized-zirconia) anode in the feed of CH4-CO2 mixtures as simulated-biogas at 800 °C were evaluated. The results showed that CO2 had strong influences on both reaction processes. The increase in CO2 partial pressure resulted in the decrease in anode overvoltage, although open-circuit voltage was dropped. Besides that, the simulation result based on a power-law model for equimolar CH4-CO2 mixture revealed that coking hazard could be suppressed along the fuel flow channel in both open-circuit and closed-circuit conditions.

  8. Theoretical rocket performance of JP-4 fuel with mixtures of liquid ozone and fluorine

    NASA Technical Reports Server (NTRS)

    Huff, Vearl N; Gordon, Sanford

    1957-01-01

    Data were estimated by means of a heat correction equation using data for JP-4 fuel with mixtures of oxygen and flourine. The estimated data were checked for several cases by direct calculations. The difference in specific impulse between the estimated and directly calculated values was from 0.2 to 0.8 pound-second per pound. The maximum value of specific impulse was 334.9 pound-seconds per pound for a combustion-chamber pressure of 600 pounds per square inch absolute and an exit pressure of 1 atmosphere.

  9. Theoretical Rocket Performance of JP-4 Fuel with Several Fluorine-Oxygen Mixtures Assuming Equilibrium Composition

    NASA Technical Reports Server (NTRS)

    Gordon, Sanford

    1958-01-01

    Theoretical rocket performance for equilibrium composition during expansion was calculated for JP-4 fuel with several fluorine-oxygen mixtures for a range of pressure ratios and oxidant-fuel ratios. The parameters included are specific impulse, combustion-chamber temperature, nozzle-exit temperature, molecular weight, characteristic velocity, coefficient of thrust, ratio of nozzle-exit area to throat area, specific heat at constant pressure, isentropic exponent, viscosity, thermal conductivity, and equilibrium gas compositions. A correlation is given for the effect of chamber pressure on several of the parameters. The maximum value of specific impulse for a chamber pressure of 600 pounds per square inch absolute (40.827 atm) and an exit pressure of 1 atmosphere is 325.7 for 70.37 percent fluorine in the oxidant as compared with 284.9 and 305.1 for 100 percent oxygen and 100 percent fluorine, respectively.

  10. Performance of winter rape (Brassica napus) based fuel mixtures in diesel engines

    SciTech Connect

    Wagner, G.L.; Peterson, C.L.

    1982-01-01

    Winter rape is well adapted to the Palouse region of Northern Idaho and Eastern Washington. Nearly all of the current US production is grown in this region. Yields of 2200 to 2700 kg/ha with 45 percent oil content are common. Even though present production only 2000 to 2500 ha per year, the long history of production and good yields of oil make winter rape the best potential fuel vegetable oil crop for the region. Winter rape oil is more viscous than sunflower oil (50 cSt at 40/sup 0/C for winter rape and 35 cSt at 40/sup 0/C for sunflower oil) and about 17 times more viscous than diesel. The viscosity of the pure oil has been found too high for operation in typical diesel injector systems. Mixtures and/or additives are essential if the oil is to be a satisfactory fuel. Conversely, the fatty acid composition of witer rape oils is such that it is potentially a more favorable fuel because of reduced rates of oxidation and thermal polymerization. This paper will report on results of short and long term engine tests using winter rape, diesel, and commercial additives as the components. Selection of mixtures for long term screening tests was based on laboratory studies which included high temperature oxidation studies and temperature-viscosity data. Fuel temperature has been monitored at the outlet of the injector nozzle on operating engines so that viscosity comparisons at the actual injector temperature can be made. 1 figure, 3 tables.

  11. A Method for Microscale Combustion of Near Stoichiometric Energy Dense Liquid Fuel Mixtures

    NASA Astrophysics Data System (ADS)

    Tolmachoff, E. D.; Allmon, W. R.; Waits, C. M.

    2013-12-01

    This paper reports on the potential of a heterogeneous/homogeneous (HH) reactor for use as a fuel-flexible heat source, meeting the needs of the next generation of high temperature thermal-to-electric (TEC) portable power converters. In this class of reactor, low activation energy catalytic reactions provide a means to stabilize high activation energy homogeneous reactions. Diffusion limited surface reactions play a critical role in HH reactor operation. Surface conversion must be sufficiently fast to generate the high temperatures (~1000 K) necessary to initiate gas phase reactions. Therefore, fuel diffusivity and the reactor dimension are important parameters in governing HH reactor operation. We examine the performance of an HH reactor fuelled by propane and n-dodecane, representing two extremes of liquid hydrocarbon diffusivity, as a function of confining reactor dimension. Unburned fuel/air mixtures are close to stoichiometric, which is an important factor in minimizing the amount of excess air and, therefore, balance of plant energy costs. At moderate levels of confinement, the reactor is capable producing high, uniform temperatures for both fuels.

  12. The impact of air-fuel mixture composition on SI engine performance during natural gas and producer gas combustion

    NASA Astrophysics Data System (ADS)

    Przybyła, G.; Postrzednik, S.; Żmudka, Z.

    2016-09-01

    The paper summarizers results of experimental tests of SI engine fuelled with gaseous fuels such as, natural gas and three mixtures of producer gas substitute that simulated real producer gas composition. The engine was operated under full open throttle and charged with different air-fuel mixture composition (changed value of air excess ratio). The spark timing was adjusted to obtain maximum brake torque (MBT) for each fuel and air-fuel mixture. This paper reports engine indicated performance based on in-cylinder, cycle resolved pressure measurements. The engine performance utilizing producer gas in terms of indicated efficiency is increased by about 2 percentage points when compared to fuelling with natural gas. The engine power de-rating when producer gas is utilized instead the natural gas, varies from 24% to 28,6% under stoichiometric combustion conditions. For lean burn (λ=1.5) the difference are lower and varies from 22% to 24.5%.

  13. INITIAL ANALYSIS OF TRANSIENT POWER TIME LAG DUE TO HETEROGENEITY WITHIN THE TREAT FUEL MATRIX.

    SciTech Connect

    D.M. Wachs; A.X. Zabriskie, W.R. Marcum

    2014-06-01

    The topic Nuclear Safety encompasses a broad spectrum of focal areas within the nuclear industry; one specific aspect centers on the performance and integrity of nuclear fuel during a reactivity insertion accident (RIA). This specific accident has proven to be fundamentally difficult to theoretically characterize due to the numerous empirically driven characteristics that quantify the fuel and reactor performance. The Transient Reactor Test (TREAT) facility was designed and operated to better understand fuel behavior under extreme (i.e. accident) conditions; it was shutdown in 1994. Recently, efforts have been underway to commission the TREAT facility to continue testing of advanced accident tolerant fuels (i.e. recently developed fuel concepts). To aid in the restart effort, new simulation tools are being used to investigate the behavior of nuclear fuels during facility’s transient events. This study focuses specifically on the characterizing modeled effects of fuel particles within the fuel matrix of the TREAT. The objective of this study was to (1) identify the impact of modeled heterogeneity within the fuel matrix during a transient event, and (2) demonstrate acceptable modeling processes for the purpose of TREAT safety analyses, specific to fuel matrix and particle size. Hypothetically, a fuel that is dominantly heterogeneous will demonstrate a clearly different temporal heating response to that of a modeled homogeneous fuel. This time difference is a result of the uniqueness of the thermal diffusivity within the fuel particle and fuel matrix. Using MOOSE/BISON to simulate the temperature time-lag effect of fuel particle diameter during a transient event, a comparison of the average graphite moderator temperature surrounding a spherical particle of fuel was made for both types of fuel simulations. This comparison showed that at a given time and with a specific fuel particle diameter, the fuel particle (heterogeneous) simulation and the homogeneous simulation

  14. Discontinuous Bubble Nucleation Due to a Metastable Condensation Transition in Polymer-CO2 Mixtures.

    PubMed

    Xu, Xiaofei; Cristancho, Diego E; Costeux, Stéphane; Wang, Zhen-Gang

    2013-05-16

    We combine a newly developed density-functional theory with the string method to calculate the minimum free energy path of bubble nucleation in compressible polymer-CO2 mixtures. Nucleation is initiated by saturating the polymer liquid with high pressure CO2 and subsequently reducing the pressure to ambient condition. Below a critical temperature, we find that there is a discontinuous drop in the nucleation barrier with increased initial CO2 pressure, as a result of an underlying metastable transition from a CO2-rich-vapor phase to a CO2-rich-liquid phase. This phenomenon is different from previously proposed nucleation mechanisms involving metastable transitions.

  15. Increase in ozone due to the use of biodiesel fuel rather than diesel fuel.

    PubMed

    Thang, Phan Quang; Muto, Yusuke; Maeda, Yasuaki; Trung, Nguyen Quang; Itano, Yasuyuki; Takenaka, Norimichi

    2016-09-01

    The consumption of fuel by vehicles emits nitrogen oxides (NOx) and non-methane hydrocarbons (NMHCs) into the atmosphere, which are important ozone precursors. Ozone is formed as a secondary pollutant via photochemical processes and is not emitted directly into the atmosphere. In this paper, the ozone increase resulting from the use of biodiesel and diesel fuels was investigated, and the different ozone formation trends were experimentally evaluated. Known amounts of exhaust gas from a power generator operated using biodiesel and diesel fuels were added to ambient air. The quality of the ambient air, such as the initial NMHC and NOx concentrations, and the irradiation intensity have an effect on the ozone levels. When 30 cm(3) of biodiesel fuel exhaust gas (BFEG) or diesel fuel exhausted gas (DFEG) was added to 18 dm(3) of ambient air, the highest ratios of ozone increase from BFEG compared with DFEG in Japan and Vietnam were 31.2 and 42.8%, respectively, and the maximum ozone increases resulting from DFEG and BFEG compared with the ambient air in Japan were 17.4 and 26.4 ppb, respectively. The ozone increase resulting from the use of BFEG was large and significant compared to that from DFEG under all experimental conditions. The ozone concentration increased as the amount of added exhaust gas increased. The ozone increase from the Jatropha-BFEG was slightly higher than that from waste cooking oil-BFEG. PMID:27396671

  16. Increase in ozone due to the use of biodiesel fuel rather than diesel fuel.

    PubMed

    Thang, Phan Quang; Muto, Yusuke; Maeda, Yasuaki; Trung, Nguyen Quang; Itano, Yasuyuki; Takenaka, Norimichi

    2016-09-01

    The consumption of fuel by vehicles emits nitrogen oxides (NOx) and non-methane hydrocarbons (NMHCs) into the atmosphere, which are important ozone precursors. Ozone is formed as a secondary pollutant via photochemical processes and is not emitted directly into the atmosphere. In this paper, the ozone increase resulting from the use of biodiesel and diesel fuels was investigated, and the different ozone formation trends were experimentally evaluated. Known amounts of exhaust gas from a power generator operated using biodiesel and diesel fuels were added to ambient air. The quality of the ambient air, such as the initial NMHC and NOx concentrations, and the irradiation intensity have an effect on the ozone levels. When 30 cm(3) of biodiesel fuel exhaust gas (BFEG) or diesel fuel exhausted gas (DFEG) was added to 18 dm(3) of ambient air, the highest ratios of ozone increase from BFEG compared with DFEG in Japan and Vietnam were 31.2 and 42.8%, respectively, and the maximum ozone increases resulting from DFEG and BFEG compared with the ambient air in Japan were 17.4 and 26.4 ppb, respectively. The ozone increase resulting from the use of BFEG was large and significant compared to that from DFEG under all experimental conditions. The ozone concentration increased as the amount of added exhaust gas increased. The ozone increase from the Jatropha-BFEG was slightly higher than that from waste cooking oil-BFEG.

  17. 33 CFR 155.330 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on U.S. non-oceangoing ships.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Oily mixture (bilge slops)/fuel... MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS Vessel Equipment § 155.330 Oily mixture (bilge slops... on board all oily mixtures and is equipped to discharge these oily mixtures to a reception...

  18. 33 CFR 155.330 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on U.S. non-oceangoing ships.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Oily mixture (bilge slops)/fuel... MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS Vessel Equipment § 155.330 Oily mixture (bilge slops... on board all oily mixtures and is equipped to discharge these oily mixtures to a reception...

  19. Dip-in Indicators for Visual Differentiation of Fuel Mixtures Based on Wettability of Fluoroalkylchlorosilane-Coated Inverse Opal Films.

    PubMed

    Sedighi, Abootaleb; Qiu, Shuang; Wong, Michael C K; Li, Paul C H

    2015-12-30

    We have developed the dip-in indicator based on the inverse opal film (IOF) for visual differentiation of organic liquid mixtures, such as oil/gasoline or ethanol/gasoline fuel mixtures. The IOF consists of a three-dimensional porous structure with a highly ordered periodic arrangement of nanopores. The specularly reflected light at the interface of the nanopores and silica walls contributes to the structural color of the IOF film. This color disappears when the nanopores are infiltrated by a liquid with a similar refractive index to silica. The disappearance of the structural color provides a means to differentiate various liquid fuel mixtures based on their wettability of the nanopores in the IOF-based indicators. For differentiation of various liquid mixtures, we tune the wettability threshold of the indicator in such a way that it is wetted (color disappears) by one liquid but is not wetted by the other (color remains). Although colorimetric differentiation of liquids based on IOF wettability has been reported, differentiation of highly similar liquid mixtures require complicated readout approaches. It is known that the IOF wettability is controlled by multiple surface properties (e.g., oleophobicity) and structural properties (e.g., neck angle and film thickness) of the nanostructure. Therefore, we aim to exploit the combined tuning of these properties for differentiation of fuel mixtures with close compositions. In this study, we have demonstrated that, for the first time, the IOF-based dip-in indicator is able to detect a slight difference in the fuel mixture composition (i.e., 0.4% of oil content). Moreover, the color/no-color differentiation platform is simple, powerful, and easy-to-read. This platform makes the dip-in indicator a promising tool for authentication and determination of fuel composition at the point-of-purchase or point-of-use. PMID:26634404

  20. Dip-in Indicators for Visual Differentiation of Fuel Mixtures Based on Wettability of Fluoroalkylchlorosilane-Coated Inverse Opal Films.

    PubMed

    Sedighi, Abootaleb; Qiu, Shuang; Wong, Michael C K; Li, Paul C H

    2015-12-30

    We have developed the dip-in indicator based on the inverse opal film (IOF) for visual differentiation of organic liquid mixtures, such as oil/gasoline or ethanol/gasoline fuel mixtures. The IOF consists of a three-dimensional porous structure with a highly ordered periodic arrangement of nanopores. The specularly reflected light at the interface of the nanopores and silica walls contributes to the structural color of the IOF film. This color disappears when the nanopores are infiltrated by a liquid with a similar refractive index to silica. The disappearance of the structural color provides a means to differentiate various liquid fuel mixtures based on their wettability of the nanopores in the IOF-based indicators. For differentiation of various liquid mixtures, we tune the wettability threshold of the indicator in such a way that it is wetted (color disappears) by one liquid but is not wetted by the other (color remains). Although colorimetric differentiation of liquids based on IOF wettability has been reported, differentiation of highly similar liquid mixtures require complicated readout approaches. It is known that the IOF wettability is controlled by multiple surface properties (e.g., oleophobicity) and structural properties (e.g., neck angle and film thickness) of the nanostructure. Therefore, we aim to exploit the combined tuning of these properties for differentiation of fuel mixtures with close compositions. In this study, we have demonstrated that, for the first time, the IOF-based dip-in indicator is able to detect a slight difference in the fuel mixture composition (i.e., 0.4% of oil content). Moreover, the color/no-color differentiation platform is simple, powerful, and easy-to-read. This platform makes the dip-in indicator a promising tool for authentication and determination of fuel composition at the point-of-purchase or point-of-use.

  1. Analysis of effect of flameholder characteristics on lean, premixed, partially vaporized fuel-air mixtures quality and nitrogen oxides emissions

    NASA Technical Reports Server (NTRS)

    Cooper, L. P.

    1981-01-01

    An analysis was conducted of the effect of flameholding devices on the precombustion fuel-air characteristics and on oxides of nitrogen (NOx) emissions for combustion of premixed partially vaporized mixtures. The analysis includes the interrelationships of flameholder droplet collection efficiency, reatomization efficiency and blockage, and the initial droplet size distribution and accounts for the contribution of droplet combustion in partially vaporized mixtures to NOx emissions. Application of the analytical procedures is illustrated and parametric predictions of NOx emissions are presented.

  2. La2O3 Nano powders by mixture of fuels approach through chemical combustion for dielectric studies

    NASA Astrophysics Data System (ADS)

    Nithesh Sharma, G.; Venkateswara Rao, K.; Sesha Sai Kumar, V.; Shilpa Chakra, Ch; Rajendar, V.; Ranjith Reddy, P.

    2015-02-01

    La2O3 which is considered as a promising substitute for present SiO2 Gate oxide material in CMOS devices has been synthesized by mixture of fuel method . The method involves the mixing of the Lanthanum Nitrate with, mixture 1:1 of Urea and Glycine. The fuel to oxidizer ratio (Ψ) has been maintained as 1.25. The powders were studied by several physical characterization techniques such as X-ray diffraction (XRD), Thermo gravimetric analysis (TGA) and Differential Thermal analysis (DTA) and dielectric properties have been studied using LCR meter. Surface morphology has been studied by SEM. Particle size has been analysed using Particle analyzer.

  3. Experimental research on the rotating detonation in gaseous fuels-oxygen mixtures

    NASA Astrophysics Data System (ADS)

    Kindracki, J.; Wolański, P.; Gut, Z.

    2011-04-01

    An experimental study on rotating detonation is presented in this paper. The study was focused on the possibility of using rotating detonation in a rocket engine. The research was divided into two parts: the first part was devoted to obtaining the initiation of rotating detonation in fuel-oxygen mixture; the second was aimed at determination of the range of propagation stability as a function of chamber pressure, composition, and geometry. Additionally, thrust and specific impulse were determined in the latter stage. In the paper, only rich mixture is described, because using such a composition in rocket combustion chambers maximizes the specific impulse and thrust. In the experiments, two kinds of geometry were examined: cylindrical and cylindrical-conic, the latter can be simulated by a simple aerospike nozzle. Methane, ethane, and propane were used as fuel. The pressure-time courses in the manifolds and in the chamber are presented. The thrust-time profile and detonation velocity calculated from measured pressure peaks are shown. To confirm the performance of a rocket engine with rotating detonation as a high energy gas generator, a model of a simple engine was designed, built, and tested. In the tests, the model of the engine was connected to the dump tank. This solution enables different environmental conditions from a range of flight from 16 km altitude to sea level to be simulated. The obtained specific impulse for pressure in the chamber of max. 1.2 bar and a small nozzle expansion ratio of about 3.5 was close to 1,500 m/s.

  4. Solution combustion synthesis of strontium aluminate, SrAl2O4, powders: single-fuel versus fuel-mixture approach.

    PubMed

    Ianoş, Robert; Istratie, Roxana; Păcurariu, Cornelia; Lazău, Radu

    2016-01-14

    The solution combustion synthesis of strontium aluminate, SrAl2O4, via the classic single-fuel approach and the modern fuel-mixture approach was investigated in relation to the synthesis conditions, powder properties and thermodynamic aspects. The single-fuel approach (urea or glycine) did not yield SrAl2O4 directly from the combustion reaction. The absence of SrAl2O4 was explained by the low amount of energy released during the combustion process, in spite of the highly negative values of the standard enthalpy of reaction and standard Gibbs free energy. In the case of single-fuel recipes, the maximum combustion temperatures measured by thermal imaging (482 °C - urea, 941 °C - glycine) were much lower than the calculated adiabatic temperatures (1864 °C - urea, 2147 °C - glycine). The fuel-mixture approach (urea and glycine) clearly represented a better option, since (α,β)-SrAl2O4 resulted directly from the combustion reaction. The maximum combustion temperature measured in the case of a urea and glycine fuel mixture was the highest one (1559 °C), which was relatively close to the calculated adiabatic temperature (1930 °C). The addition of a small amount of flux, such as H3BO3, enabled the formation of pure α-SrAl2O4 directly from the combustion reaction.

  5. Rat muscle opacity decrease due to the osmosis of a simple mixture.

    PubMed

    Oliveira, Luís; Lage, Armindo; Pais Clemente, M; Tuchin, Valery V

    2010-01-01

    It is known that the fibrous structure of muscle causes light scattering. This phenomenon occurs due to the refractive index discontinuities located between muscle fibers and interstitial fluid. To study the possibility of reducing light scattering inside muscle, we consider its spectral transmittance evolution during an immersion treatment with an optical clearing solution containing ethanol, glycerol, and distilled water. Our methodology consists of registering spectral transmittance of muscle samples while immersed in that solution. With the spectral data collected, we represent the transmittance evolution for some wavelengths during the treatment applied. Additionally, we study the variations that the treatment has caused on the samples regarding tissue refractive index and mass. By analyzing microscopic photographs of tissue cross section, we can also verify changes in the internal arrangement of muscle fibers caused by the immersion treatment. Due to a mathematical model that we develop, we can explain the variations observed in the studied parameters and estimate the amount of optical clearing agent that has diffused into the tissue samples during the immersion treatment. At the end of the study, we observe and explain the improvement in tissue spectral transmittance, which is approximately 65% after 20 min.

  6. Rat muscle opacity decrease due to the osmosis of a simple mixture

    NASA Astrophysics Data System (ADS)

    Oliveira, Luís; Lage, Armindo; Pais Clemente, M.; Tuchin, Valery V.

    2010-09-01

    It is known that the fibrous structure of muscle causes light scattering. This phenomenon occurs due to the refractive index discontinuities located between muscle fibers and interstitial fluid. To study the possibility of reducing light scattering inside muscle, we consider its spectral transmittance evolution during an immersion treatment with an optical clearing solution containing ethanol, glycerol, and distilled water. Our methodology consists of registering spectral transmittance of muscle samples while immersed in that solution. With the spectral data collected, we represent the transmittance evolution for some wavelengths during the treatment applied. Additionally, we study the variations that the treatment has caused on the samples regarding tissue refractive index and mass. By analyzing microscopic photographs of tissue cross section, we can also verify changes in the internal arrangement of muscle fibers caused by the immersion treatment. Due to a mathematical model that we develop, we can explain the variations observed in the studied parameters and estimate the amount of optical clearing agent that has diffused into the tissue samples during the immersion treatment. At the end of the study, we observe and explain the improvement in tissue spectral transmittance, which is approximately 65% after 20 min.

  7. Nuclear Criticality Control and Safety of Plutonium-Uranium Fuel Mixtures Outside Reactors

    SciTech Connect

    Biswas, D; Mennerdahl, D

    2008-06-23

    The ANSI/ANS 8.12 standard was first approved in July 1978. At that time, this edition was applicable to operations with plutonium-uranium oxide (MOX) fuel mixtures outside reactors and was limited to subcritical limits for homogeneous systems. The next major revision, ANSI/ANS-8.12-1987, included the addition of subcritical limits for heterogeneous systems. The standard was subsequently reaffirmed in February 1993. During late 1990s, substantial work was done by the ANS 8.12 Standard Working Group to re-examine the technical data presented in the standard using the latest codes and cross section sets. Calculations performed showed good agreement with the values published in the standard. This effort resulted in the reaffirmation of the standard in March 2002. The standard is currently in a maintenance mode. After 2002, activities included discussions to determine the future direction of the standard and to follow the MOX standard development by the International Standard Organization (ISO). In 2007, the Working Group decided to revise the standard to extend the areas of applicability by providing a wider range of subcritical data. The intent is to cover a wider domain of MOX fuel fabrication and operations. It was also decided to follow the ISO MOX standard specifications (related to MOX density and isotopics) and develop a new set of subcritical limits for homogeneous systems. This has resulted in the submittal (and subsequent approval) of the project initiation notification system form (PINS) in 2007.

  8. Reductions in aircraft particulate emissions due to the use of Fischer-Tropsch fuels

    NASA Astrophysics Data System (ADS)

    Beyersdorf, A. J.; Timko, M. T.; Ziemba, L. D.; Bulzan, D.; Corporan, E.; Herndon, S. C.; Howard, R.; Miake-Lye, R.; Thornhill, K. L.; Winstead, E.; Wey, C.; Yu, Z.; Anderson, B. E.

    2014-01-01

    The use of alternative fuels for aviation is likely to increase due to concerns over fuel security, price stability, and the sustainability of fuel sources. Concurrent reductions in particulate emissions from these alternative fuels are expected because of changes in fuel composition including reduced sulfur and aromatic content. The NASA Alternative Aviation Fuel Experiment (AAFEX) was conducted in January-February 2009 to investigate the effects of synthetic fuels on gas-phase and particulate emissions. Standard petroleum JP-8 fuel, pure synthetic fuels produced from natural gas and coal feedstocks using the Fischer-Tropsch (FT) process, and 50% blends of both fuels were tested in the CFM-56 engines on a DC-8 aircraft. To examine plume chemistry and particle evolution with time, samples were drawn from inlet probes positioned 1, 30, and 145 m downstream of the aircraft engines. No significant alteration to engine performance was measured when burning the alternative fuels. However, leaks in the aircraft fuel system were detected when operated with the pure FT fuels as a result of the absence of aromatic compounds in the fuel. Dramatic reductions in soot emissions were measured for both the pure FT fuels (reductions in mass of 86% averaged over all powers) and blended fuels (66%) relative to the JP-8 baseline with the largest reductions at idle conditions. At 7% power, this corresponds to a reduction from 7.6 mg kg-1 for JP-8 to 1.2 mg kg-1 for the natural gas FT fuel. At full power, soot emissions were reduced from 103 to 24 mg kg-1 (JP-8 and natural gas FT, respectively). The alternative fuels also produced smaller soot (e.g., at 85% power, volume mean diameters were reduced from 78 nm for JP-8 to 51 nm for the natural gas FT fuel), which may reduce their ability to act as cloud condensation nuclei (CCN). The reductions in particulate emissions are expected for all alternative fuels with similar reductions in fuel sulfur and aromatic content regardless of the

  9. 33 CFR 155.350 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of less...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... must meet current standards in 46 CFR part 162, subpart 162.050 by the date set forth in paragraphs (a... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Oily mixture (bilge slops)/fuel... mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of less than 400...

  10. 33 CFR 155.350 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of less...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... must meet current standards in 46 CFR part 162, subpart 162.050 by the date set forth in paragraphs (a... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Oily mixture (bilge slops)/fuel... mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of less than 400...

  11. 33 CFR 155.350 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of less...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... must meet current standards in 46 CFR part 162, subpart 162.050 by the date set forth in paragraphs (a... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Oily mixture (bilge slops)/fuel... mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of less than 400...

  12. Electrorefining process and apparatus for recovery of uranium and a mixture of uranium and plutonium from spent fuels

    DOEpatents

    Ackerman, John P.; Miller, William E.

    1989-01-01

    An electrorefining process and apparatus for the recovery of uranium and a mixture of uranium and plutonium from spent fuel using an electrolytic cell having a lower molten cadmium pool containing spent nuclear fuel, an intermediate electrolyte pool, an anode basket containing spent fuel, and two cathodes, the first cathode composed of either a solid alloy or molten cadmium and the second cathode composed of molten cadmium. Using this cell, additional amounts of uranium and plutonium from the anode basket are dissolved in the lower molten cadmium pool, and then substantially pure uranium is electrolytically transported and deposited on the first alloy or molten cadmium cathode. Subsequently, a mixture of uranium and plutonium is electrotransported and deposited on the second molten cadmium cathode.

  13. Electrorefining process and apparatus for recovery of uranium and a mixture of uranium and plutonium from spent fuels

    DOEpatents

    Ackerman, J.P.; Miller, W.E.

    1987-11-05

    An electrorefining process and apparatus for the recovery of uranium and a mixture of uranium and plutonium from spent fuels is disclosed using an electrolytic cell having a lower molten cadmium pool containing spent nuclear fuel, an intermediate electrolyte pool, an anode basket containing spent fuels, two cathodes and electrical power means connected to the anode basket, cathodes and lower molten cadmium pool for providing electrical power to the cell. Using this cell, additional amounts of uranium and plutonium from the anode basket are dissolved in the lower molten cadmium pool, and then purified uranium is electrolytically transported and deposited on a first molten cadmium cathode. Subsequently, a mixture of uranium and plutonium is electrotransported and deposited on a second cathode. 3 figs.

  14. Vibrational and rotational CARS measurements of nitrogen in afterglow of streamer discharge in atmospheric pressure fuel/air mixtures

    NASA Astrophysics Data System (ADS)

    Pendleton, S. J.; Montello, A.; Carter, C.; Lempert, W.; Gundersen, M. A.

    2012-12-01

    The use of nonequilibrium plasma generated by nanosecond discharges to ignite fuel/air mixtures, known as transient plasma ignition (TPI), has been shown to effectively reduce ignition delay and improve engine performance relative to spark ignition for combustion engines. While this method is potentially useful for many engine applications, at present the underlying physics are poorly understood. This work uses coherent anti-Stokes Raman spectroscopy (CARS) to measure the rotational and vibrational excitation of nitrogen molecules in the discharge afterglow in a variety of fuel/air mixtures outside the limits of combustion in order to elucidate the thermal behaviour of TPI. The time evolution of relative populations of vibrationally excited states of nitrogen in the electronic ground state are reported for each gas mixture; it is shown that generation of these vibrationally excited states is inefficient during the discharge in air but that generation occurs at a high rate roughly 5 µs following the discharge; with the addition of fuels vibrationally excited states are observed during the discharge but an increase in population is still seen at 5 µs. Possible mechanisms for this behaviour are discussed. In addition, rotational temperature increases of at least 500 K are reported for all gas mixtures. The effect of this temperature increase on ignition, reaction rates, and thermal energy pathways are discussed.

  15. Disease burden due to biomass cooking-fuel-related household air pollution among women in India

    PubMed Central

    Sehgal, Meena; Rizwan, Suliankatchi Abdulkader; Krishnan, Anand

    2014-01-01

    Background Household air pollution (HAP) due to biomass cooking fuel use is an important risk factor for a range of diseases, especially among adult women who are primary cooks, in India. About 80% of rural households in India use biomass fuel for cooking. The aim of this study is to estimate the attributable cases (AC) for four major diseases/conditions associated with biomass cooking fuel use among adult Indian women. Methods We used the population attributable fraction (PAF) method to calculate the AC of chronic bronchitis, tuberculosis (TB), cataract, and stillbirths due to exposure to biomass cooking fuel. A number of data sources were accessed to obtain population totals and disease prevalence rates. A meta-analysis was conducted to obtain adjusted pooled odds ratios (ORs) for strength of association. Using this, PAF and AC were calculated using a standard formula. Results were presented as number of AC and 95% confidence intervals (CI). Results The fixed effects pooled OR obtained from the meta-analysis were 2.37 (95% CI: 1.59, 3.54) for chronic bronchitis, 2.33 (1.65, 3.28) for TB, 2.16 (1.42, 3.26) for cataract, and 1.26 (1.12, 1.43) for stillbirths. PAF varied across conditions being maximum (53%) for chronic bronchitis in rural areas and least (1%) for cataract in older age and urban areas. About 2.4 (95% CI: 1.4, 3.1) of 5.6 m cases of chronic bronchitis, 0.3 (0.2, 0.4) of 0.76 m cases of TB, 5.0 (2.8, 6.7) of 51.4 m cases of cataract among adult Indian women and 0.02 (0.01, 0.03) of 0.15 m stillbirths across India are attributable to HAP due to biomass cooking fuel. These estimates should be cautiously interpreted in the light of limitations discussed which relate to exposure assessment, exposure characterization, and age-specific prevalence of disease. Conclusions HAP due to biomass fuel has diverse and major impacts on women’s health in India. Although challenging, incorporating the agenda of universal clean fuel access or cleaner technology within

  16. 10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... these regulations. (c) Solar mixtures. OFE will grant a permanent mixtures exemption for the use of a mixture of solar energy (including wind, tide, and other intermittent sources) and petroleum or natural gas, where: (1) Solar energy will account for at least 20 percent of the total annual Btu heat...

  17. 10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... these regulations. (c) Solar mixtures. OFE will grant a permanent mixtures exemption for the use of a mixture of solar energy (including wind, tide, and other intermittent sources) and petroleum or natural gas, where: (1) Solar energy will account for at least 20 percent of the total annual Btu heat...

  18. Experimental investigation of homogeneous charge compression ignition combustion of biodiesel fuel with external mixture formation in a CI engine.

    PubMed

    Ganesh, D; Nagarajan, G; Ganesan, S

    2014-01-01

    In parallel to the interest in renewable fuels, there has also been increased interest in homogeneous charge compression ignition (HCCI) combustion. HCCI engines are being actively developed because they have the potential to be highly efficient and to produce low emissions. Even though HCCI has been researched extensively, few challenges still exist. These include controlling the combustion at higher loads and the formation of a homogeneous mixture. To obtain better homogeneity, in the present investigation external mixture formation method was adopted, in which the fuel vaporiser was used to achieve excellent HCCI combustion in a single cylinder air-cooled direct injection diesel engine. In continuation of our previous works, in the current study a vaporised jatropha methyl ester (JME) was mixed with air to form a homogeneous mixture and inducted into the cylinder during the intake stroke to analyze the combustion, emission and performance characteristics. To control the early ignition of JME vapor-air mixture, cooled (30 °C) Exhaust gas recirculation (EGR) technique was adopted. The experimental result shows 81% reduction in NOx and 72% reduction in smoke emission. PMID:24383396

  19. Experimental investigation of homogeneous charge compression ignition combustion of biodiesel fuel with external mixture formation in a CI engine.

    PubMed

    Ganesh, D; Nagarajan, G; Ganesan, S

    2014-01-01

    In parallel to the interest in renewable fuels, there has also been increased interest in homogeneous charge compression ignition (HCCI) combustion. HCCI engines are being actively developed because they have the potential to be highly efficient and to produce low emissions. Even though HCCI has been researched extensively, few challenges still exist. These include controlling the combustion at higher loads and the formation of a homogeneous mixture. To obtain better homogeneity, in the present investigation external mixture formation method was adopted, in which the fuel vaporiser was used to achieve excellent HCCI combustion in a single cylinder air-cooled direct injection diesel engine. In continuation of our previous works, in the current study a vaporised jatropha methyl ester (JME) was mixed with air to form a homogeneous mixture and inducted into the cylinder during the intake stroke to analyze the combustion, emission and performance characteristics. To control the early ignition of JME vapor-air mixture, cooled (30 °C) Exhaust gas recirculation (EGR) technique was adopted. The experimental result shows 81% reduction in NOx and 72% reduction in smoke emission.

  20. Fuel mixture stratification as a method for improving homogeneous charge compression ignition engine operation

    DOEpatents

    Dec, John E.; Sjoberg, Carl-Magnus G.

    2006-10-31

    A method for slowing the heat-release rate in homogeneous charge compression ignition ("HCCI") engines that allows operation without excessive knock at higher engine loads than are possible with conventional HCCI. This method comprises injecting a fuel charge in a manner that creates a stratified fuel charge in the engine cylinder to provide a range of fuel concentrations in the in-cylinder gases (typically with enough oxygen for complete combustion) using a fuel with two-stage ignition fuel having appropriate cool-flame chemistry so that regions of different fuel concentrations autoignite sequentially.

  1. Thermodynamic substantiation of the existence of a phase transition point with a change in the structure of the solid-fuel mixture glycidyl azide Polymer/RDX

    NASA Astrophysics Data System (ADS)

    Futko, S. I.

    2012-09-01

    With the help of thermodynamic calculations for a wide range of solid-fuel mixtures glycidyl azide polymer (GAP)/RDX with a component ratio from 100% GAP/0% RDX to 0% GAP/100% RDX we have found a structural transition point corresponding to a mixture of 60.8 mass % of RDX in GAP at which a sharp change in the trend of thermodynamic combustion characteristics of these mixtures occurs. The given point is determined from the condition of equality of molar fractions of C and O atoms in the above mixtures. It is pressure-independent, corresponds to the minimum point on the curve of the rate of combustion of the mixture as a function of its composition and to the structural change in the solid-fuel mixture GAP/RDX from amorphous to polycrystalline, and is a phase transition point.

  2. An experimental study of the autoignition characteristics of conventional jet fuel/oxidizer mixtures: Jet-A and JP-8

    SciTech Connect

    Kumar, Kamal; Sung, Chih-Jen

    2010-04-15

    Ignition delay times of Jet-A/oxidizer and JP-8/oxidizer mixtures are measured using a heated rapid compression machine at compressed charge pressures corresponding to 7, 15, and 30 bar, compressed temperatures ranging from 650 to 1100 K, and equivalence ratios varying from 0.42 to 2.26. When using air as the oxidant, two oxidizer-to-fuel mass ratios of 13 and 19 are investigated. To achieve higher compressed temperatures for fuel lean mixtures (equivalence ratio of {proportional_to}0.42), argon dilution is also used and the corresponding oxidizer-to-fuel mass ratio is 84.9. For the conditions studied, experimental results show two-stage ignition characteristics for both Jet-A and JP-8. Variations of both the first-stage and overall ignition delays with compressed temperature, compressed pressure, and equivalence ratio are reported and correlated. It is noted that the negative temperature coefficient phenomenon becomes more prominent at relatively lower pressures. Furthermore, the first-stage-ignition delay is found to be less sensitive to changes in equivalence ratio and primarily dependent on temperature. (author)

  3. Fuel flexible fuel injector

    DOEpatents

    Tuthill, Richard S; Davis, Dustin W; Dai, Zhongtao

    2015-02-03

    A disclosed fuel injector provides mixing of fuel with airflow by surrounding a swirled fuel flow with first and second swirled airflows that ensures mixing prior to or upon entering the combustion chamber. Fuel tubes produce a central fuel flow along with a central airflow through a plurality of openings to generate the high velocity fuel/air mixture along the axis of the fuel injector in addition to the swirled fuel/air mixture.

  4. Reactive atomistic simulations of shock-induced initiation processes in mixtures of ammonium nitrate and fuel oil

    NASA Astrophysics Data System (ADS)

    Thompson, Aidan P.; Shan, Tzu-Ray

    2014-05-01

    Ammonium nitrate mixed with fuel oil (ANFO) is a commonly used blasting agent. In this paper we investigated the shock properties of pure ammonium nitrate (AN) and two different mixtures of ammonium nitrate and n-dodecane by characterizing their Hugoniot states. We simulated shock compression of pure AN and ANFO mixtures using the Multi-scale Shock Technique, and observed differences in chemical reaction. We also performed a large-scale explicit sub-threshold shock of AN crystal with a 10 nm void filled with 4.4 wt% of n-dodecane. We observed the formation of hotspots and enhanced reactivity at the interface region between AN and n-dodecane molecules.

  5. Bioaccumulation of fossil fuel components during single-compound and complex-mixture exposures of Daphnia magna

    SciTech Connect

    Dauble, D.D.; Carlile, D.W.; Hanf, R.W. Jr.

    1986-07-01

    The authors conducted tests with the water flea (Daphnia magna) to compare the bioaccumulation of compounds presented alone with the bioaccumulation of these same compounds when they were presented within a complex coal liquid, water-soluble fraction. Phenol and aniline were used as representative compounds because they are highly soluble, moderately toxic, and common to many fossil fuel liquid products and corresponding wastes. The tests were primarily designed to aid in development of predictive models relating to the transport and fate of components from complex mixtures in aquatic biota.

  6. Plasma barodiffusion in inertial-confinement-fusion implosions: application to observed yield anomalies in thermonuclear fuel mixtures.

    PubMed

    Amendt, Peter; Landen, O L; Robey, H F; Li, C K; Petrasso, R D

    2010-09-10

    The observation of large, self-generated electric fields (≥10(9)  V/m) in imploding capsules using proton radiography has been reported [C. K. Li, Phys. Rev. Lett. 100, 225001 (2008)]. A model of pressure gradient-driven diffusion in a plasma with self-generated electric fields is developed and applied to reported neutron yield deficits for equimolar D3He [J. R. Rygg, Phys. Plasmas 13, 052702 (2006)] and (DT)3He [H. W. Herrmann, Phys. Plasmas 16, 056312 (2009)] fuel mixtures and Ar-doped deuterium fuels [J. D. Lindl, Phys. Plasmas 11, 339 (2004)]. The observed anomalies are explained as a mild loss of deuterium nuclei near capsule center arising from shock-driven diffusion in the high-field limit.

  7. Notes from the Field: Intoxication and Deaths Associated with Ingestion of a Racing Fuel and Carbonated Soft Drink Mixture - Tennessee, January 2016.

    PubMed

    Fill, Mary-Margaret A; Seger, Donna L; Dunn, John R; Schaffner, William; Jones, Timothy F

    2016-01-01

    In January 2016, the Tennessee Poison Center and Tennessee Department of Health learned of the deaths of two adolescents, and the nonfatal intoxication of two other adolescents, after ingestion of a mixture of racing fuel (approximately 100% methanol) and a carbonated soft drink. The Tennessee Department of Health reviewed medical records and police reports to learn more about the racing fuel source, assess ongoing risk, and guide prevention efforts. These are the first reported deaths in the United States associated with ingestion of this racing fuel mixture. PMID:27281631

  8. Response of the global climate to changes in atmospheric chemical composition due to fossil fuel burning

    NASA Technical Reports Server (NTRS)

    Cess, R. D.; Hameed, S.; Hogan, J. S.

    1980-01-01

    Tropospheric ozone and methane might increase in the future as the result of increasing anthropogenic emissions of CO, NOx and CH4 due to fossil fuel burning. Since O3 and CH4 are both greenhouse gases, increases in their concentrations could augment global warming due to larger future amounts of atmospheric CO2. To test this possible climatic impact, a zonal energy-balance climate model has been combined with a vertically-averaged tropospheric chemical model. The latter model includes all relevant chemical reactions which affect species derived from H2O, O2, CH4 and NOx. The climate model correspondingly incorporates changes in the infrared heating of the surface-troposphere system resulting from chemically induced changes in tropospheric ozone and methane. This coupled climate-chemical model indicates that global climate is sensitive to changes in emissions of CO, NOx and CH4, and that future increases in these emissions could enhance global warming due to increasing atmospheric CO2.

  9. Response of the global climate to changes in atmospheric chemical composition due to fossil fuel burning

    NASA Technical Reports Server (NTRS)

    Hameed, S.; Cess, R. D.; Hogan, J. S.

    1980-01-01

    Recent modeling of atmospheric chemical processes (Logan et al, 1978; Hameed et al, 1979) suggests that tropospheric ozone and methane might significantly increase in the future as the result of increasing anthropogenic emissions of CO, NO(x), and CH4 due to fossil fuel burning. Since O3 and CH4 are both greenhouse gases, increases in their concentrations could augment global warming due to larger future amounts of atmospheric CO2. To test the possible climatic impact of changes in tropospheric chemical composition, a zonal energy-balance climate model has been combined with a vertically averaged tropospheric chemical model. The latter model includes all relevant chemical reactions which affect species derived from H2O, O2, CH4, and NO(x). The climate model correspondingly incorporates changes in the infrared heating of the surface-troposphere system resulting from chemically induced changes in tropospheric ozone and methane. This coupled climate-chemical model indicates that global climate is sensitive to changes in emissions of CO, NO(x) and CH4, and that future increases in these emissions could augment global warming due to increasing atmospheric CO2.

  10. Flow and Mixture Optimization for a Fuel Stratification Engine Using PIV and PLIF Techniques

    NASA Astrophysics Data System (ADS)

    Li, Y.; Zhao, H.; Ma, T.

    2006-07-01

    This paper describes an application of PIV (particle image velocimetry) and two-tracer PLIF (planar laser-induced florescence) techniques to optimize the in-cylinder flow and to visualize two fuels distribution simultaneously for developing a fuel stratification engine. This research was carried out on a twin-spark four-valve SI engine. The PIV measurement results shows that a strong tumbling flow was produced in the cylinder as the intake valves were shrouded. The flow exhibited a symmetrical distribution in the plane perpendicular to the cylinder axis from the early stage of intake until the late stage of compression. This flow pattern helps to stratify the two fuels introduced from separate ports into two regions laterally. The stratification of fuels was observed visually by the two-tracer PLIF technique. During the PLIF measurement, two tracers, 3- pentanone and N, N-dimethylaniline (DMA), were doped into two fuels, hexane and iso-octane, respectively. Their fluorescence emissions were separated by two optical band-pass filters and recorded by a single ICCD camera simultaneously via an image doubling system. The PLIF measurement result shows that two fuels were well stratified.

  11. Experimental analysis of performance degradation of micro-tubular solid oxide fuel cells fed by different fuel mixtures

    NASA Astrophysics Data System (ADS)

    Calise, F.; Restucccia, G.; Sammes, N.

    This paper analyzes the thermodynamic and electrochemical dynamic performance of an anode supported micro-tubular solid oxide fuel cell (SOFC) fed by different types of fuel. The micro-tubular SOFC used is anode supported, consisting of a NiO and Gd 0.2Ce 0.8O 2- x (GDC) cermet anode, thin GDC electrolyte, and a La 0.6Sr 0.4Co 0.2Fe 0.8O 3- y (LSCF) and GDC cermet cathode. The fabrication of the cells under investigation is briefly summarized, with emphasis on the innovations with respect to traditional techniques. Such micro-tubular cells were tested using a Test Stand consisting of: a vertical tubular furnace, an electrical load, a galvanostast, a bubbler, gas pipelines, temperature, pressure and flow meters. The tests on the micro-SOFC were performed using H 2, CO, CH 4 and H 2O in different combinations at 550 °C, to determine the cell polarization curves under several load cycles. Long-term experimental tests were also performed in order to assess degradation of the electrochemical performance of the cell. Results of the tests were analyzed aiming at determining the sources of the cell performance degradation. Authors concluded that the cell under investigation is particularly sensitive to the carbon deposition which significantly reduces cell performance, after few cycles, when fed by light hydrocarbons. A significant performance degradation is also detected when hydrogen is used as fuel. In this case, the authors ascribe the degradation to the micro-cracks, the change in materials crystalline structure and problems with electrical connections.

  12. Lean mixture engine testing and evaluation program. [for automobile engine pollution and fuel performances

    NASA Technical Reports Server (NTRS)

    Dowdy, M. W.; Hoehn, F. W.; Griffin, D. C.

    1975-01-01

    Experimental results for fuel consumption and emissions are presented for a 350 CID (5.7 liter) Chevrolet V-8 engine modified for lean operation with gasoline. The lean burn engine achieved peak thermal efficiency at an equivalence ratio of 0.75 and a spark advance of 60 deg BTDC. At this condition the lean burn engine demonstrated a 10% reduction in brake specific fuel consumption compared with the stock engine; however, NOx and hydrocarbon emissions were higher. With the use of spark retard and/or slightly lower equivalence ratios, the NOx emissions performance of the stock engine was matched while showing a 6% reduction in brake specific fuel consumption. Hydrocarbon emissions exceeded the stock values in all cases. Diagnostic data indicate that lean performance in the engine configuration tested is limited by ignition delay, cycle-to-cycle pressure variations, and cylinder-to-cylinder distribution.

  13. Metabolic engineering of Clostridium acetobutylicum for the enhanced production of isopropanol-butanol-ethanol fuel mixture.

    PubMed

    Jang, Yu-Sin; Malaviya, Alok; Lee, Joungmin; Im, Jung Ae; Lee, Sang Yup; Lee, Julia; Eom, Moon-Ho; Cho, Jung-Hee; Seung, Do Young

    2013-01-01

    Butanol is considered as a superior biofuel, which is conventionally produced by clostridial acetone-butanol-ethanol (ABE) fermentation. Among ABE, only butanol and ethanol can be used as fuel alternatives. Coproduction of acetone thus causes lower yield of fuel alcohols. Thus, this study aimed at developing an improved Clostridium acetobutylicum strain possessing enhanced fuel alcohol production capability. For this, we previously developed a hyper ABE producing BKM19 strain was further engineered to convert acetone into isopropanol. The BKM19 strain was transformed with the plasmid pIPA100 containing the sadh (primary/secondary alcohol dehydrogenase) and hydG (putative electron transfer protein) genes from the Clostridium beijerinckii NRRL B593 cloned under the control of the thiolase promoter. The resulting BKM19 (pIPA100) strain produced 27.9 g/l isopropanol-butanol-ethanol (IBE) as a fuel alcohols with negligible amount of acetone (0.4 g/l) from 97.8 g/l glucose in lab-scale (2 l) batch fermentation. Thus, this metabolically engineered strain was able to produce 99% of total solvent produced as fuel alcohols. The scalability and stability of BKM19 (pIPA100) were evaluated at 200 l pilot-scale fermentation, which showed that the fuel alcohol yield could be improved to 0.37 g/g as compared to 0.29 g/g obtained at lab-scale fermentation, while attaining a similar titer. To the best of our knowledge, this is the highest titer of IBE achieved and the first report on the large scale fermentation of C. acetobutylicum for IBE production.

  14. High-repetition-rate laser ignition of fuel-air mixtures.

    PubMed

    Hsu, Paul S; Roy, Sukesh; Zhang, Zhili; Sawyer, Jordan; Slipchenko, Mikhail N; Mance, Jason G; Gord, James R

    2016-04-01

    A laser-ignition (LI) method is presented that utilizes a high-repetition-rate (HRR) nanosecond laser to reduce minimal ignition energies of individual pulses by ∼10 times while maintaining comparable total energies. The most common LI employs a single nanosecond-laser pulse with energies on the order of tens of millijoules to ignite combustible gaseous mixtures. Because of the requirements of high energy per pulse, fiber coupling of traditional LI systems is difficult to implement in real-world systems with limited optical access. The HRR LI method demonstrated here has an order of magnitude lower per-pulse energy requirement than the traditional single-pulse LI technique, potentially allowing delivery through standard commercial optical fibers. Additionally, the HRR LI approach significantly increases the ignition probability of lean combustible mixtures in high-speed flows while maintaining low individual pulse energies. PMID:27192289

  15. Calculated flame temperature (CFT) modeling of fuel mixture lower flammability limits.

    PubMed

    Zhao, Fuman; Rogers, William J; Mannan, M Sam

    2010-02-15

    Heat loss can affect experimental flammability limits, and it becomes indispensable to quantify flammability limits when apparatus quenching effect becomes significant. In this research, the lower flammability limits of binary hydrocarbon mixtures are predicted using calculated flame temperature (CFT) modeling, which is based on the principle of energy conservation. Specifically, the hydrocarbon mixture lower flammability limit is quantitatively correlated to its final flame temperature at non-adiabatic conditions. The modeling predictions are compared with experimental observations to verify the validity of CFT modeling, and the minor deviations between them indicated that CFT modeling can represent experimental measurements very well. Moreover, the CFT modeling results and Le Chatelier's Law predictions are also compared, and the agreement between them indicates that CFT modeling provides a theoretical justification for the Le Chatelier's Law. PMID:19819067

  16. Methane production from stillage/manure mixtures at a fuel alcohol plant

    SciTech Connect

    Williams, D.W.; Eastman, R.V.

    1986-01-01

    Steel tanks were retrofitted as anaerobic digesters to process stillage wastes from a fuel alcohol plant. In addition to the stillage, poultry manure will be digested to produce a total of almost 10,000 cubic meters of biogas per day. Electricity and thermal energy will be cogenerated from the methane, and the digested solids marketed as nursery soil.

  17. Trace element partitioning in ashes from boilers firing pure wood or mixtures of solid waste with respect to fuel composition, chlorine content and temperature

    SciTech Connect

    Saqib, Naeem Bäckström, Mattias

    2014-12-15

    Highlights: • Different solids waste incineration is discussed in grate fired and fluidized bed boilers. • We explained waste composition, temperature and chlorine effects on metal partitioning. • Excessive chlorine content can change oxide to chloride equilibrium partitioning the trace elements in fly ash. • Volatility increases with temperature due to increase in vapor pressure of metals and compounds. • In Fluidized bed boiler, most metals find themselves in fly ash, especially for wood incineration. - Abstract: Trace element partitioning in solid waste (household waste, industrial waste, waste wood chips and waste mixtures) incineration residues was investigated. Samples of fly ash and bottom ash were collected from six incineration facilities across Sweden including two grate fired and four fluidized bed incinerators, to have a variation in the input fuel composition (from pure biofuel to mixture of waste) and different temperature boiler conditions. As trace element concentrations in the input waste at the same facilities have already been analyzed, the present study focuses on the concentration of trace elements in the waste fuel, their distribution in the incineration residues with respect to chlorine content of waste and combustion temperature. Results indicate that Zn, Cu and Pb are dominating trace elements in the waste fuel. Highly volatile elements mercury and cadmium are mainly found in fly ash in all cases; 2/3 of lead also end up in fly ash while Zn, As and Sb show a large variation in distribution with most of them residing in the fly ash. Lithophilic elements such as copper and chromium are mainly found in bottom ash from grate fired facilities while partition mostly into fly ash from fluidized bed incinerators, especially for plants fuelled by waste wood or ordinary wood chips. There is no specific correlation between input concentration of an element in the waste fuel and fraction partitioned to fly ash. Temperature and chlorine

  18. Greenhouse Impact Due to the Use of Combustible Fuels: Life Cycle Viewpoint and Relative Radiative Forcing Commitment

    PubMed Central

    Palosuo, Taru; Holmgren, Kristina; Savolainen, Ilkka

    2008-01-01

    Extensive information on the greenhouse impacts of various human actions is important in developing effective climate change mitigation strategies. The greenhouse impacts of combustible fuels consist not only of combustion emissions but also of emissions from the fuel production chain and possible effects on the ecosystem carbon storages. It is important to be able to assess the combined, total effect of these different emissions and to express the results in a comprehensive way. In this study, a new concept called relative radiative forcing commitment (RRFC) is presented and applied to depict the greenhouse impact of some combustible fuels currently used in Finland. RRFC is a ratio that accounts for the energy absorbed in the Earth system due to changes in greenhouse gas concentrations (production and combustion of fuel) compared to the energy released in the combustion of fuel. RRFC can also be expressed as a function of time in order to give a dynamic cumulative picture on the caused effect. Varying time horizons can be studied separately, as is the case when studying the effects of different climate policies on varying time scales. The RRFC for coal for 100 years is about 170, which means that in 100 years 170 times more energy is absorbed in the atmosphere due to the emissions of coal combustion activity than is released in combustion itself. RRFC values of the other studied fuel production chains varied from about 30 (forest residues fuel) to 190 (peat fuel) for the 100-year study period. The length of the studied time horizon had an impact on the RRFC values and, to some extent, on the relative positions of various fuels. PMID:18521657

  19. Dermal, eye, and oral toxicologic evaluations of brass powder, fog oil, diesel fuel, and their mixtures. Report for 1 May-30 September 1985 on Phase 3

    SciTech Connect

    Mayhew, D.A.; Smith, S.H.; Doyle, G.L.; Kreuger, J.C.; Mellon, K.A.

    1985-12-01

    Five test articles were evaluated to establish their eye and skin irritation potential and their oral and dermal toxicity. The test articles evaluated were as followed: 1) Brass Powder, 2) Fog Oil, 3) Diesel Fuel, 4) 0.75 parts Fog Oil:1 part Brass Powder (w/w mixture), and 5) 0.7 parts Diesel Fuel: 1 part Brass Powder (w/w mixture). Oral studies were conducted utilizing the Fischer-344 albino rat as the test system; all other studies utilized the New Zealand White Albino Rabbit as the test system. Results obtained in these studies are summarized.

  20. Separation of gaseous hydrogen from a water-hydrogen mixture in a fuel cell power system operating in a weightless environment

    NASA Technical Reports Server (NTRS)

    Romanowski, William E. (Inventor); Suljak, George T. (Inventor)

    1989-01-01

    A fuel cell power system for use in a weightless environment, such as in space, includes a device for removing water from a water-hydrogen mixture condensed from the exhaust from the fuel cell power section of the system. Water is removed from the mixture in a centrifugal separator, and is fed into a holding, pressure operated water discharge valve via a Pitot tube. Entrained nondissolved hydrogen is removed from the Pitot tube by a bleed orifice in the Pitot tube before the water reaches the water discharge valve. Water discharged from the valve thus has a substantially reduced hydrogen content.

  1. Response of selected plant and insect species to simulated SRM exhaust mixtures and to exhaust components from SRM fuels

    NASA Technical Reports Server (NTRS)

    Heck, W. W.

    1980-01-01

    The possible biologic effects of exhaust products from solid rocket motor (SRM) burns associated with the space shuttle are examined. The major components of the exhaust that might have an adverse effect on vegetation, HCl and Al2O3 are studied. Dose response curves for native and cultivated plants and selected insects exposed to simulated exhaust and component chemicals from SRM exhaust are presented. A system for dispensing and monitoring component chemicals of SRM exhaust (HCl and Al2O3) and a system for exposing test plants to simulated SRM exhaust (controlled fuel burns) are described. The effects of HCl, Al2O3, and mixtures of the two on the honeybee, the corn earworm, and the common lacewing and the effects of simulated exhaust on the honeybee are discussed.

  2. Solution combustion synthesis of CeO{sub 2}-CeAlO{sub 3} nano-composites by mixture-of-fuels approach

    SciTech Connect

    Aruna, S.T.; Kini, N.S. Rajam, K.S.

    2009-04-02

    Nano-composites of CeO{sub 2}-CeAlO{sub 3} are synthesised by solution combustion method employing (a) urea and (b) a mixture of urea and glycine as fuels with corresponding metal nitrates. The as-prepared powders are all nano-sized (5-30 nm) and the same is confirmed by broadening of the X-ray diffraction peaks and transmission electron microscopy. A starting composition of Ce:Al in the atomic ratio 4:6 gives rise to different phases depending on the fuel being used for combustion. When urea alone is used as fuel, nano-crystalline CeO{sub 2} phase is formed with Al{sub 2}O{sub 3} being in the amorphous state. When the mixture of fuels is used, a mixture of nano-sized CeO{sub 2} and CeAlO{sub 3} phases is obtained. However, upon sintering at 1400 deg. C in air, the stable phases CeO{sub 2} and {alpha}-Al{sub 2}O{sub 3} are formed in both the cases. Combustion synthesis using mixture-of-fuels is proposed to be a route to stabilise low oxidation compounds such as CeAlO{sub 3}.

  3. Numerical modeling of flame-balls in fuel-air mixtures

    NASA Technical Reports Server (NTRS)

    Smooke, Mitchell D.; Ern, Alexandre

    1995-01-01

    At low gravity, when buoyancy effects are small, flame-balls can be generated. These are stationary spherical structures whose existence appears to require a near-limit mixture, a small Lewis number and heat losses from radiation. It is our goal to combine computational modeling with existing experimental and theoretical studies (NASA) of these structures so that an improved understanding of flammability limits and near-limit phenomena will occur. The question of flammability limits is of fundamental importance and has long been examined. It is of great practical importance to predict, from first principles, a limit mixture strength that agrees with experimental values for the configuration at hand. Flame-balls provide an excellent configuration in which convective losses can be eliminated and the resulting stable solutions are produced from a diffusive, reactive and radiative balance. Although analytical modeling provides convincing evidence that the key physical ingredients of flame-balls have been identified, quantitative confirmation can only come from detailed numerical simulations. Our goal is to predict theoretically the mass fractions of the species and the temperature as functions of the independent coordinate r.

  4. Novel process and catalytic materials for converting CO2 and H2 containing mixtures to liquid fuels and chemicals.

    PubMed

    Meiri, Nora; Dinburg, Yakov; Amoyal, Meital; Koukouliev, Viatcheslav; Nehemya, Roxana Vidruk; Landau, Miron V; Herskowitz, Moti

    2015-01-01

    Carbon dioxide and water are renewable and the most abundant feedstocks for the production of chemicals and fungible fuels. However, the current technologies for production of hydrogen from water are not competitive. Therefore, reacting carbon dioxide with hydrogen is not economically viable in the near future. Other alternatives include natural gas, biogas or biomass for the production of carbon dioxide, hydrogen and carbon monoxide mixtures that react to yield chemicals and fungible fuels. The latter process requires a high performance catalyst that enhances the reverse water-gas-shift (RWGS) reaction and Fischer-Tropsch synthesis (FTS) to higher hydrocarbons combined with an optimal reactor system. Important aspects of a novel catalyst, based on a Fe spinel and three-reactor system developed for this purpose published in our recent paper and patent, were investigated in this study. Potassium was found to be a key promoter that improves the reaction rates of the RWGS and FTS and increases the selectivity of higher hydrocarbons while producing mostly olefins. It changed the texture of the catalyst, stabilized the Fe-Al-O spinel, thus preventing decomposition into Fe3O4 and Al2O3. Potassium also increased the content of Fe5C2 while shifting Fe in the oxide and carbide phases to a more reduced state. In addition, it increased the relative exposure of carbide iron on the catalysts surface, the CO2 adsorption and the adsorption strength. A detailed kinetic model of the RWGS, FTS and methanation reactions was developed for the Fe spinel catalyst based on extensive experimental data measured over a range of operating conditions. Significant oligomerization activity of the catalyst was found. Testing the pelletized catalyst with CO2, CO and H2 mixtures over a range of operating conditions demonstrated its high productivity to higher hydrocarbons. The composition of the liquid (C5+) was found to be a function of the potassium content and the composition of the feedstock

  5. Novel process and catalytic materials for converting CO2 and H2 containing mixtures to liquid fuels and chemicals.

    PubMed

    Meiri, Nora; Dinburg, Yakov; Amoyal, Meital; Koukouliev, Viatcheslav; Nehemya, Roxana Vidruk; Landau, Miron V; Herskowitz, Moti

    2015-01-01

    Carbon dioxide and water are renewable and the most abundant feedstocks for the production of chemicals and fungible fuels. However, the current technologies for production of hydrogen from water are not competitive. Therefore, reacting carbon dioxide with hydrogen is not economically viable in the near future. Other alternatives include natural gas, biogas or biomass for the production of carbon dioxide, hydrogen and carbon monoxide mixtures that react to yield chemicals and fungible fuels. The latter process requires a high performance catalyst that enhances the reverse water-gas-shift (RWGS) reaction and Fischer-Tropsch synthesis (FTS) to higher hydrocarbons combined with an optimal reactor system. Important aspects of a novel catalyst, based on a Fe spinel and three-reactor system developed for this purpose published in our recent paper and patent, were investigated in this study. Potassium was found to be a key promoter that improves the reaction rates of the RWGS and FTS and increases the selectivity of higher hydrocarbons while producing mostly olefins. It changed the texture of the catalyst, stabilized the Fe-Al-O spinel, thus preventing decomposition into Fe3O4 and Al2O3. Potassium also increased the content of Fe5C2 while shifting Fe in the oxide and carbide phases to a more reduced state. In addition, it increased the relative exposure of carbide iron on the catalysts surface, the CO2 adsorption and the adsorption strength. A detailed kinetic model of the RWGS, FTS and methanation reactions was developed for the Fe spinel catalyst based on extensive experimental data measured over a range of operating conditions. Significant oligomerization activity of the catalyst was found. Testing the pelletized catalyst with CO2, CO and H2 mixtures over a range of operating conditions demonstrated its high productivity to higher hydrocarbons. The composition of the liquid (C5+) was found to be a function of the potassium content and the composition of the feedstock.

  6. In situ measurements of water transfer due to different mechanisms in a proton exchange membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Husar, Attila; Higier, Andrew; Liu, Hongtan

    Water management is of critical importance in a proton exchange membrane (PEM) fuel cell, in particular, those based on a sulfonic acid polymer, which requires water to conduct protons. Yet there are limited in situ studies of water transfer through the membrane and no data are available for water transfer due to individual mechanisms through the membrane in an operational fuel cell. Thus it is the objective of this study to measure water transfer through the membrane due to each individual mechanism in an operational PEM fuel cell. The three different mechanisms of water transfer, i.e., electro-osmotic drag, diffusion and hydraulic permeation are isolated by specially imposed boundary conditions. Therefore water transfer through the membrane due to each mechanism is measured separately. In this study, all the data is collected in an actual assembled operational fuel cell. The experimental results show that water transfer due to hydraulic permeation, i.e. the pressure difference between the anode and cathode is at least an order of magnitude lower than those due to the other two mechanisms. The data for water transfer due to diffusion through the membrane are in good agreement with some of the ex situ data in the literature. The data for electro-osmosis show that the number of water molecules dragged per proton increases not only with temperature but also with current density, which is different from existing data in the literature. The methodology used in this study is simple and can be easily adopted for in situ water transfer measurement due to different mechanisms in other PEM fuel cells without any cell modifications.

  7. Fuel mixture approach for solution combustion synthesis of Ca{sub 3}Al{sub 2}O{sub 6} powders

    SciTech Connect

    Ianos, Robert Lazau, Ioan; Pacurariu, Cornelia; Barvinschi, Paul

    2009-07-15

    Single-phase 3CaO.Al{sub 2}O{sub 3} powders were prepared via solution combustion synthesis using a fuel mixture of urea and {beta}-alanine. The concept of using this fuel mixture comes from the individual reactivity of calcium nitrate and aluminum nitrate with respect to urea and {beta}-alanine. It was proved that urea is the optimum fuel for Al(NO{sub 3}){sub 3} whereas {beta}-alanine is the most suitable fuel for Ca(NO{sub 3}){sub 2}. X-ray diffraction and thermal analysis investigations revealed that heating at 300 deg. C the precursor mixture containing the desired metal nitrates, urea and {beta}-alanine triggers a vigorous combustion reaction, which yields single-phase nanocrystalline 3CaO.Al{sub 2}O{sub 3} powder (33.3 nm). In this case additional annealing was no longer required. The use of a single fuel failed to ensure the formation of 3CaO.Al{sub 2}O{sub 3} directly from the combustion reaction. After annealing at 900 deg. C for 1 h, the powders obtained by using a single fuel (urea or {beta}-alanine) developed a phase composition comprising of 3CaO.Al{sub 2}O{sub 3}, 12CaO.7Al{sub 2}O{sub 3} and CaO.

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

    SciTech Connect

    Gupta, Kamlesh G.; Echekki, Tarek

    2011-02-15

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

  9. Reducing the deactivation of Ni-metal during the catalytic partial oxidation of a surrogate diesel fuel mixture

    SciTech Connect

    Haynes, Daniel J.; Campos, Andrew; Smith, Mark W.; Berry, David A.; Shekhawat, Dushyant; Spivey, James J.

    2010-09-01

    Ni catalysts are active and selective for the conversion of hydrocarbon into synthesis gas. However, conventional supported Ni catalysts rapidly deactivate at the high temperatures required for partial oxidation of diesel fuel by sintering and metal vaporization, as well as by carbon deposition and sulfur poisoning. Thus, to reduce deactivation Ni (3 wt%) was substituted into the structures of Ba-hexaaluminate (BNHA) and La–Sr–Zr pyrochlore (LSZN), and their activity was compared to a supported Ni/Al2O3 for the catalytic partial oxidation (CPOX) of a surrogate diesel fuel. Characterization by XRD showed a single phase -alumina for the hexaaluminate, while LSZN had a pyrochlore structure with a defect SrZrO3 perovskite phase. Temperature programmed reduction experiments confirmed Ni was reducible in all catalysts. XANES results confirmed that Ni atoms were substituted into the hexaaluminate and pyrochlore structures, as spectra for each catalyst showed different coordination environments for Ni compared to a NiO standard. During CPOX activity tests (T = 900°C and WHSV= 50,000 scc/gcat/h), the LSZN pyrochlore produced stable H2 and CO yields in the presence of 5 wt% 1-methylnaphthalene and 50ppmw dibenzothiophene/n-tetradecane for 2 h, while both Ni/Al2O3 and BNHA catalysts were irreversibly deactivated by this mixture over the same time. Activity loss was strongly linked to carbon formation

  10. Surface Tension Driven Instability Due to Internal Heat Sources in a Horizontal Layer of Binary Liquid Mixture

    NASA Astrophysics Data System (ADS)

    Takashima, Masaki; Mori, Kazuhiro

    1988-02-01

    Linear stability theory is applied to the problem of the onset of surface-tension-driven instability in a horizontal layer of binary liquid mixture confined at the bottom by a rigid, thermally insulating wall and at the top by a non-deformable free surface at which Newton’s cooling law is assumed to hold. It is also assumed that the liquid layer is heated by uniformly distributed internal heat sources which produce a nonlinear temperature profile and, in addition, a nonlinear concentration profile through the Soret effect. By neglecting small terms including the Soret coefficient ST, an eigenvalue system of eighth order is derived and is then solved exactly. For wide ranges of various parameters, the conditions under which instability sets in are determined numerically. As compared with the corresponding linear temperature case (M. Takashima: J. Phys. Soc. Jpn. 47 (1979) 1321; 49 (1980) 802), it is found that the nonlinear temperature profile produced by internal heat sources makes the liquid layer less stable for both stationary and oscillatory modes.

  11. Quantification of Back-End Nuclear Fuel Cycle Metrics Uncertainties Due to Cross Sections

    SciTech Connect

    Tracy E. Stover, Jr.

    2007-11-01

    This work examines uncertainties in the back end fuel cycle metrics of isotopic composition, decay heat, radioactivity, and radiotoxicity. Most advanced fuel cycle scenarios, including the ones represented in this work, are limited by one or more of these metrics, so that quantification of them becomes of great importance in order to optimize or select one of these scenarios. Uncertainty quantification, in this work, is performed by propagating cross-section covariance data, and later number density covariance data, through a reactor physics and depletion code sequence. Propagation of uncertainty is performed primarily via the Efficient Subspace Method (ESM). ESM decomposes the covariance data into singular pairs and perturbs input data along independent directions of the uncertainty and only for the most significant values of that uncertainty. Results of these perturbations being collected, ESM directly calculates the covariance of the observed output posteriori. By exploiting the rank deficient nature of the uncertainty data, ESM works more efficiently than traditional stochastic sampling, but is shown to produce equivalent results. ESM is beneficial for very detailed models with large amounts of input data that make stochastic sampling impractical. In this study various fuel cycle scenarios are examined. Simplified, representative models of pressurized water reactor (PWR) and boiling water reactor (BWR) fuels composed of both uranium oxide and mixed oxides are examined. These simple models are intended to give a representation of the uncertainty that can be associated with open uranium oxide fuel cycles and closed mixed oxide fuel cycles. The simplified models also serve as a demonstration to show that ESM and stochastic sampling produce equivalent results, because these models require minimum computer resources and have amounts of input data small enough such that either method can be quickly implemented and a numerical experiment performed. The simplified

  12. Ignition delay of a gas mixture above a liquid fuel pool

    NASA Technical Reports Server (NTRS)

    Schiller, D. N.; Sirignano, W. A.

    1991-01-01

    A computational study has been made of transient heat transfer and fluid flow of an axisymmetric two-layer gas-and-liquid system heated from above by a small hot spot (e.g., a hot wire or pilot flame) located close to the liquid surface. The gas phase is unconfined above the liquid pool. The effects of varying gravity level (0.0001 to 1 gn), liquid pool height, and heater height are investigated. Thermocapillary convection induced by the nonuniform heating of the liquid surface combines with buoyancy forces to affect the heat transfer and the transport of fuel vapor toward the heat source. At reduced gravity, gas-phase conduction is comparable to the incident radiation at the liquid surface, whereas at 1 gn, buoyant convection carries the heat upward from the heat source and, therefore, the liquid is heated primarily by radiation.

  13. Fuel additives from SO/sub 2/ treated mixtures of amides and esters derived from vegetable oil, tall oil acid, or aralkyl acid

    SciTech Connect

    Efner, H. F.; Schiff, S.

    1985-03-12

    Vegetable oils, particularly soybean oil, tall oil acid, or aralkyl acids, particularly phenylstearic acid, are reacted with multiamines, particularly tetraethylenepentamine, to form a product mixture for subsequent reaction with SO/sub 2/ to produce a product mix that has good detergent properties in fuels.

  14. 33 CFR 155.350 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of less...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Oily mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of less than 400 gross tons. 155.350 Section 155.350 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL...

  15. 33 CFR 155.330 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on U.S. non-oceangoing ships.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Oily mixture (bilge slops)/fuel oil tank ballast water discharges on U.S. non-oceangoing ships. 155.330 Section 155.330 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS...

  16. 33 CFR 155.330 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on U.S. non-oceangoing ships.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Oily mixture (bilge slops)/fuel oil tank ballast water discharges on U.S. non-oceangoing ships. 155.330 Section 155.330 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS...

  17. Toxicity of jet fuel aliphatic and aromatic hydrocarbon mixtures on human epidermal keratinocytes: evaluation based on in vitro cytotoxicity and interleukin-8 release.

    PubMed

    Yang, Jen-Hung; Lee, Chia-Hue; Monteiro-Riviere, Nancy A; Riviere, Jim E; Tsang, Chau-Loong; Chou, Chi-Chung

    2006-08-01

    Jet fuels are complex mixtures of aliphatic (ALI) and aromatic (ARO) hydrocarbons that vary significantly in individual cytotoxicity and proinflammatory activity in human epidermal keratinocytes (HEK). In order to delineate the toxicological interactions among individual hydrocarbons in a mixture and their contributions to cutaneous toxicity, nine ALI and five ARO hydrocarbons were each divided into five (high/medium/low cytotoxic and strong/weak IL-8 induction) groups and intra/inter-mixed to assess for their mixture effects on HEK mortality and IL-8 release. Addition of single hydrocarbon to JP-8 fuel was also evaluated for their changes in fuel dermatotoxicity. The results indicated that when hydrocarbons were mixed, HEK mortality and IL-8 release were not all predictable by their individual ability affecting these two parameters. The lowest HEK mortality (7%) and the highest IL-8 production were induced with mixtures including high cytotoxic and weak IL-8 inductive ARO hydrocarbons. Antagonistic reactions not consistently correlated with ALI carbon chain length and ARO structure were evident and carried different weight in the overall mixture toxicities. Single addition of benzene, toluene, xylene or ethylbenzene for up to tenfold in JP-8 did not increase HEK mortality while single addition of ALI hydrocarbons exhibited dose-related differential response in IL-8. In an all ALI environment, no single hydrocarbon is the dominating factor in the determination of HEK cytotoxicity while deletion of hexadecane resulted in a 2.5-fold increase in IL-8 production. Overall, decane, undecane and dodecane were the major hydrocarbons associated with high cytotoxicity while tetradecane, pentadecane and hexadecane were those which had the greatest buffering effect attenuating dermatotoxicity. The mixture effects must be considered when evaluating jet fuel toxicity to HEK.

  18. Estimation of wildfire size and risk changes due to fuels treatments

    USGS Publications Warehouse

    Cochrane, M.A.; Moran, C.J.; Wimberly, M.C.; Baer, A.D.; Finney, M.A.; Beckendorf, K.L.; Eidenshink, J.; Zhu, Z.

    2012-01-01

    Human land use practices, altered climates, and shifting forest and fire management policies have increased the frequency of large wildfires several-fold. Mitigation of potential fire behaviour and fire severity have increasingly been attempted through pre-fire alteration of wildland fuels using mechanical treatments and prescribed fires. Despite annual treatment of more than a million hectares of land, quantitative assessments of the effectiveness of existing fuel treatments at reducing the size of actual wildfires or how they might alter the risk of burning across landscapes are currently lacking. Here, we present a method for estimating spatial probabilities of burning as a function of extant fuels treatments for any wildland fire-affected landscape. We examined the landscape effects of more than 72 000 ha of wildland fuel treatments involved in 14 large wildfires that burned 314 000 ha of forests in nine US states between 2002 and 2010. Fuels treatments altered the probability of fire occurrence both positively and negatively across landscapes, effectively redistributing fire risk by changing surface fire spread rates and reducing the likelihood of crowning behaviour. Trade offs are created between formation of large areas with low probabilities of increased burning and smaller, well-defined regions with reduced fire risk.

  19. Simulation of detonation of ammonium nitrate fuel oil mixture confined by aluminum: edge angles for DSD

    SciTech Connect

    Short, Mark; Quirk, James J; Kiyanda, Charles B; Jackson, Scott I; Briggs, Matthew E; Shinas, Micheal A

    2010-01-01

    Non-ideal high explosives are typically porous, low-density materials with a low detonation velocity (3--5 km/s) and long detonation reaction zone ({approx} cms). As a result, the interaction of a non-ideal high explosive with an inert confiner can be markedly different than for a conventional high explosive. Issues arise, for example, with light stiff confiners where the confiner can drive the high explosive (HE) through a Prandtl-Meyer fan at the HE/confiner interface rather than the HE driving the confiner. For a non-ideal high explosive confined by a high sound speed inert such that the detonation velocity is lower than the inert sound speed, the flow is subsonic and thus shockless in the confiner. In such cases, the standard detonation shock dynamics methodology, which requires a positive edge-angle be specified at the HE/confiner interface in order that the detonation shape be divergent, cannot be directly utilized. In order to study how detonation shock dynamics can be utilized in such cases, numerical simulations of the detonation of ammonium nitrate-fuel oil (ANFO) confined by aluminum 6061 are conducted.

  20. Reductions in vehicle fuel consumption due to refinements in aerodynamic design. [for trailer trucks

    NASA Technical Reports Server (NTRS)

    Saltzman, E. J.

    1979-01-01

    Over-the-highway fuel consumption and coastdown drag tests were performed on cab-over-engine, van type trailer trucks and modifications of these vehicles incorporating refinements in aerodynamic design. In addition, 1/25-scale models of these configurations, and derivatives of these configurations were tested in a wind tunnel to determine the effects of wind on the magnitude of the benefits that aerodynamic refinements can provide. The results of these tests are presented for a vehicle incorporating major redesign features and for a relatively simple add-on modification. These results include projected fuel savings on the basis of annual savings per vehicle year as well as probable nationwide fuel savings.

  1. Reducing the deactivation of Ni-metal during the catalytic partial oxidation of a surrogate diesel fuel mixture

    SciTech Connect

    Haynes, Daniel J.; Campos, Andrew; Smith, Mark W.; Berry, David A.; Shekhawat, Dushyant; Spivey, James J.

    2010-09-01

    Ni catalysts are active and selective for the conversion of hydrocarbon into synthesis gas. However, conventional supported Ni catalysts rapidly deactivate at the high temperatures required for partial oxidation of diesel fuel by sintering and metal vaporization, as well as by carbon deposition and sulfur poisoning. Thus, to reduce deactivation Ni (3 wt%) was substituted into the structures of Ba-hexaaluminate (BNHA) and La–Sr–Zr pyrochlore (LSZN), and their activity was compared to a supported Ni/Al2O3 for the catalytic partial oxidation (CPOX) of a surrogate diesel fuel. Characterization by XRD showed a single phase β-alumina for the hexaaluminate, while LSZN had a pyrochlore structure with a defect SrZrO3 perovskite phase. Temperature programmed reduction experiments confirmed Ni was reducible in all catalysts. XANES results confirmed that Ni atoms were substituted into the hexaaluminate and pyrochlore structures, as spectra for each catalyst showed different coordination environments for Ni compared to a NiO standard. During CPOX activity tests (T = 900 °C and WHSV = 50,000 scc/gcat/h), the LSZN pyrochlore produced stable H2 and CO yields in the presence of 5 wt% 1-methylnaphthalene and 50 ppmw dibenzothiophene/n-tetradecane for 2 h, while both Ni/Al2O3 and BNHA catalysts were irreversibly deactivated by this mixture over the same time. Finally, activity loss was strongly linked to carbon formation.

  2. Design Concepts for Co-Production of Power, Fuels & Chemicals Via Coal/Biomass Mixtures

    SciTech Connect

    Rao, A. D.; Chen, Q.; Samuelsen, G. S.

    2012-09-30

    The overall goal of the program is to develop design concepts, incorporating advanced technologies in areas such as oxygen production, feed systems, gas cleanup, component separations and gas turbines, for integrated and economically viable coal and biomass fed gasification facilities equipped with carbon capture and storage for the following scenarios: (i) coproduction of power along with hydrogen, (ii) coproduction of power along with fuels, (iii) coproduction of power along with petrochemicals, and (iv) coproduction of power along with agricultural chemicals. To achieve this goal, specifically the following objectives are met in this proposed project: (i) identify advanced technology options and innovative preliminary design concepts that synergistically integrate plant subsections, (ii) develop steady state system simulations to predict plant efficiency and environmental signature, (iii) develop plant cost estimates by capacity factoring major subsystems or by major equipment items where required, and then capital, operating and maintenance cost estimates, and (iv) perform techno- economic analyses for the above described coproduction facilities. Thermal efficiencies for the electricity only cases with 90% carbon capture are 38.26% and 36.76% (HHV basis) with the bituminous and the lignite feedstocks respectively. For the coproduction cases (where 50% of the energy exported is in the form of electricity), the electrical efficiency, as expected, is highest for the hydrogen coproduction cases while lowest for the higher alcohols (ethanol) coproduction cases. The electrical efficiencies for Fischer-Tropsch coproduction cases are slightly higher than those for the methanol coproduction cases but it should be noted that the methanol (as well as the higher alcohol) coproduction cases produce the finished coproduct while the Fischer-Tropsch coproduction cases produce a coproduct that requires further processing in a refinery. The cross comparison of the thermal

  3. Structural and magnetic properties of manganese zinc ferrite nanoparticles prepared by solution combustion method using mixture of fuels

    NASA Astrophysics Data System (ADS)

    Angadi, V. Jagadeesha; Rudraswamy, B.; Sadhana, K.; Praveena, K.

    2016-07-01

    The structural analysis and magnetic investigation Mn1-xZnxFe2O4 with stoichiometry (x=0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0) were synthesized by solution combustion method using mixture of fuel this is first of its kind. As synthesized Mn-Zn nanoferrites were characterized by X-ray Diffractometer (XRD), Transmission electron microscopy (TEM) at room temperature. The magnetic domain relaxation was investigated by inductance spectroscopy (IS) and the observed magnetic domain relaxation frequency (fr) was increased with the increase in grain size. The Room temperature magnetic properties were studied using vibrating sample magnetometer (VSM). It was observed that the real and imaginary part of permeability (μ‧ and μ″), saturation magnetization (Ms), remanance magnetization (Mr) and magneton number (Mr/Ms) were decreases gradually with increasing Zn2+ concentration. The decrease in the saturation magnetization may be explained as, the Zn2+ concentration increases the relative number of ferric ions on the A sites diminishes and this reduces the A-B interaction. Hence synthesized materials are good for high frequency applications.

  4. Detonation cellular structure in NO{sub 2}/N{sub 2}O{sub 4}-fuel gaseous mixtures

    SciTech Connect

    Joubert, Franckie; Desbordes, Daniel; Presles, Henri-Noel

    2008-03-15

    Experimental and numerical studies of the detonation in NO{sub 2}-N{sub 2}O{sub 4}/fuel (H{sub 2}, CH{sub 4}, and C{sub 2}H{sub 6}) gaseous mixtures show that for equivalence ratio {phi}>0.8-1, (1) the detonation has a double cellular structure, the ratio between the cell size of each net being at least one order of magnitude; (2) inside the detonation reaction zone the chemical energy is released in two successive exothermic steps. Their chemical induction lengths, defined between the leading shock front and each local maximum heat release rate associated with each step, differ by at least one order of magnitude. The chemical reaction NO{sub 2} + H {yields} NO + OH is mainly responsible for the first exothermic step (fast kinetics), NO being the oxidizer on the second one (slow kinetics). Existence of correlations between calculated induction lengths and corresponding cell sizes strengthen the assumption that the cellular structure originates from local strong gradients of chemical heat release inside the detonation reaction zone. (author)

  5. Open- and closed-circuit study of an intermediate temperature SOFC directly fueled with simulated biogas mixtures

    NASA Astrophysics Data System (ADS)

    Yentekakis, Ioannis V.

    An intermediate temperature solid oxide fuel cell (SOFC) based on a gadolinia doped ceria (GDC) solid electrolyte, a Ni(Au)-GDC cermet anode and a La 0.54Sr 0.46MnO 3 perovskite cathode was tested at 600 and 640 °C on direct feed of simulated biogas mixtures. The catalytic (open-circuit) rate of the methane dry (CO 2)-reforming reaction over Ni(Au)-GDC anode was found to be maximized at about equimolar CH 4/CO 2 feed ratio. Cell power density up to 60 mW cm -2, at a cell voltage of 445 mV and a current density of 135 mA cm -2 at 640 °C, has been obtained under closed-circuit cell operation at this optimal feed ratio. Carbon deposition was found not to downgrade cell output characteristics under closed-circuit conditions at constant external loads for ∼120 h, preceded by open- or closed-circuit operation for ∼100 additional hours.

  6. Effect of fuel mixture fraction and velocity perturbations on the flame transfer function of swirl stabilized flames

    NASA Astrophysics Data System (ADS)

    Wysocki, Stefan; Di-Chiaro, Giacomo; Biagioli, Fernando

    2015-11-01

    A novel methodology is developed to decompose the classic Flame Transfer Function (FTF) used in the thermo-acoustic stability analysis of lean premix combustors into contributions of different types. The approach is applied, in the context of Large Eddy Simulation (LES), to partially-premixed and fully-premixed flames, which are stabilized via a central recirculation zone as a result of the vortex breakdown phenomenon. The first type of decomposition is into contributions driven by fuel mixture fraction and dynamic velocity fluctuations. Each of these two contributions is further split into the components of turbulent flame speed and flame surface area. The flame surface area component, driven by the pure dynamic velocity fluctuation, which is shown to be a dominant contribution to the overall FTF, is also additionally decomposed over the coherent flow structures using proper orthogonal decomposition. Using a simplified model for the dynamic response of premixed flames, it is shown that the distribution of the FTF, as obtained from LES, is closely related to the characteristics of the velocity field frequency response to the inlet perturbation. Initially, the proposed method is tested and validated with a well characterized laboratory burner geometry. Subsequently, the method is applied to an industrial gas turbine burner.

  7. High-speed mixture fraction and temperature imaging of pulsed, turbulent fuel jets auto-igniting in high-temperature, vitiated co-flows

    NASA Astrophysics Data System (ADS)

    Papageorge, Michael J.; Arndt, Christoph; Fuest, Frederik; Meier, Wolfgang; Sutton, Jeffrey A.

    2014-07-01

    In this manuscript, we describe an experimental approach to simultaneously measure high-speed image sequences of the mixture fraction and temperature fields during pulsed, turbulent fuel injection into a high-temperature, co-flowing, and vitiated oxidizer stream. The quantitative mixture fraction and temperature measurements are determined from 10-kHz-rate planar Rayleigh scattering and a robust data processing methodology which is accurate from fuel injection to the onset of auto-ignition. In addition, the data processing is shown to yield accurate temperature measurements following ignition to observe the initial evolution of the "burning" temperature field. High-speed OH* chemiluminescence (CL) was used to determine the spatial location of the initial auto-ignition kernel. In order to ensure that the ignition kernel formed inside of the Rayleigh scattering laser light sheet, OH* CL was observed in two viewing planes, one near-parallel to the laser sheet and one perpendicular to the laser sheet. The high-speed laser measurements are enabled through the use of the unique high-energy pulse burst laser system which generates long-duration bursts of ultra-high pulse energies at 532 nm (>1 J) suitable for planar Rayleigh scattering imaging. A particular focus of this study was to characterize the fidelity of the measurements both in the context of the precision and accuracy, which includes facility operating and boundary conditions and measurement of signal-to-noise ratio (SNR). The mixture fraction and temperature fields deduced from the high-speed planar Rayleigh scattering measurements exhibited SNR values greater than 100 at temperatures exceeding 1,300 K. The accuracy of the measurements was determined by comparing the current mixture fraction results to that of "cold", isothermal, non-reacting jets. All profiles, when properly normalized, exhibited self-similarity and collapsed upon one another. Finally, example mixture fraction, temperature, and OH* emission

  8. Results of turbojet engine operation tests using a 50-50 mixture of JP-4 and tributyl borate as the fuel

    NASA Technical Reports Server (NTRS)

    Schafer, Louis J , Jr; Stepka, Francis S

    1957-01-01

    An experimental investigation was conducted on a centrifugal-type turbojet engine using a 50-50 mixture of tributyl borate and JP-4 as the fuel to determine the magnitude and the location of the boric oxide deposits in the engine as well as the effect of these deposits on the engine performance. Large deposits of boric acid formed in the combustor walls and on the turbine rotor and stator blades. The deposits had no effect on the engine thrust.

  9. Carburetor mixture control apparatus

    SciTech Connect

    Dalke, A.E.

    1983-11-29

    A mixture control device is disclosed for automatically controlling the air to fuel mixture of a conventional carburetor involving a plurality of sloped radial vanes circumferentially located within the annulus formed by the booster venturi and the venturi tube. By inducing significant centrifugal motion in the air passing outside the booster venturi the problems associated with fuel to air mixture changes associated with changes in elevation and changes in seasonal temperatures are alleviated.

  10. Theoretical performance of liquid ammonia, hydrazine and mixture of liquid ammonia and hydrazine as fuels with liquid oxygen biflouride as oxidant for rocket engines : I-mixture of liquid ammonia and hydrazine

    NASA Technical Reports Server (NTRS)

    Huff, Vearl N; Gordon, Sanford

    1952-01-01

    Theoretical performance for mixture of 36.3 percent liquid ammonia and 63.7 percent hydrazine with liquid oxygen bifluoride as rocket propellant was calculated on assumption of equilibrium composition during expansion for a wide range of fuel-oxidant and expansios ratios. Parameters included were specific impulse, combustion-chamber temperature, nozzle exit temperature, composition mean molecular weight, characteristic velocity, coefficient of thrust and ratio of nozzle-exit area to throat area. For chamber pressure of 300 pounds per square inch absolute and expansion to 1 atmosphere, maximum specific impulse was 295.8 pound-seconds per pound. Five percent by weight of water in the hydrazine lowered specific impulse from about one to three units over a wide range of weight-percent fuel.

  11. Influence of the Structure of a Solid-Fuel Mixture on the Thermal Efficiency of the Combustion Chamber of an Engine System

    NASA Astrophysics Data System (ADS)

    Futko, S. I.; Koznacheev, I. A.; Ermolaeva, E. M.

    2014-11-01

    On the basis of thermodynamic calculations, the features of the combustion of a solid-fuel mixture based on the glycidyl azide polymer were investigated, the thermal cycle of the combustion chamber of a model engine system was analyzed, and the efficiency of this chamber was determined for a wide range of pressures in it and different ratios between the components of the combustible mixture. It was established that, when the pressure in the combustion chamber of an engine system increases, two maxima arise successively on the dependence of the thermal efficiency of the chamber on the weight fractions of the components of the combustible mixture and that the first maximum shifts to the side of smaller concentrations of the glycidyl azide polymer with increase in the pressure in the chamber; the position of the second maximum is independent of this pressure, coincides with the minimum on the dependence of the rate of combustion of the mixture, and corresponds to the point of its structural phase transition at which the mole fractions of the carbon and oxygen atoms in the mixture are equal. The results obtained were interpreted on the basis of the Le-Chatelier principle.

  12. Hydraulic Property Alterations due to Wettability Induced Changes by Diesel Fuels

    NASA Astrophysics Data System (ADS)

    O'Carroll, Denis

    2013-04-01

    The remediation of non-aqueous phase liquid (NAPL) contaminated sites is impeded due to subsurface complexities, including wettability. Wettability quantifies which of two immiscible fluids preferentially coats a solid. At most contaminated sites water-wetting conditions are typically assumed despite mounting evidence that is not always the case. In this study, wettability was examined for two NAPL samples of contrasting origin: a fresh and a field sample. Wettability was assessed through (i) cyclical, 'cumulative elapsed contact time' intrinsic contact angle measurements, (ii) interface jar tests, and (iii) cyclical, pseudo-static capillary pressure-saturation curves. The work as a whole demonstrated that while the fresh diesel sample was consistently water-wet, the field diesel sample exhibited repeatable cycles of wettability reversal between water drainage and imbibition. And while wettability hysteresis increased with contact time for the field diesel, the occurrence of wettability reversal at each change of saturation direction was independent of contact time. Such behavior is not easily assessed by standard wettability indices. Moreover, it contrasts with the permanent wettability alteration observed for complex organics (e.g., coal tar) observed in most studies. It is hypothesized that the cyclical wettability reversal is related to cyclical changes in intermediate pore wettability due to sorption of surface active compounds (causing NAPL-wetting imbibition) and rupturing of the the soil grain water film (causing water-wet drainage). The wettability differences between the two NAPLs may be due to additives (i.e., a surfactant) in the original formulation and/or byproducts from subsurface weathering. These results support better characterization of site-specific wettability, improved model development and more realistic site conceptual models for improved remediation efforts.

  13. Radial Displacement of Pellet Ablation Fuel in Tokamaks Due to the grad-B Effect

    NASA Astrophysics Data System (ADS)

    Parks, P. B.

    1999-11-01

    An apparent displacement of deposited pellet ablation substance toward the low-field or large-R side of the tokamak is observed during pellet injection from the low-field side, and it has been attributed to uncompensated nabla B and curvature drifts induced by the 1/R toroidal field variation. The effect was recently exploited in ASDEX-U during pellet injection from the high-field side in order to promote deeper fuel penetration. This presentation will discuss a self-consistent model that predicts the large-R velocity and transport distance. The particle source from an ablating pellet presents a significant disturbance to the plasma. Initially, an ablated ``cloudlet'' just separated from the pellet shadow is a toroidally localized, mildly diamagnetic (magnetic β_c<0.1) plasmoid, which will polarize and E× B drift towards the low-field side of the tokamak. Periodic cloud ``disruptions,'' related to the formation of striations, breed a sequence of 20 to 30 discrete cloudlets along the trajectory of the pellet, with each cloudlet carrying off the ablated mass contained in the pellet's ionized shielding channel at the moment of its birth. The cloudlets are assumed to have a cylindrical shape, with initial field-aligned profiles inherited from the shielding channel and sharp-boundary density and pressure profiles in the radial direction. The cloudlet expands along the field lines against the ambient backpressure, while it undergoes motion as a whole in the large-R direction. The rigid body motion is obtained from B\\cdotnabla× of the momentum equation, while a combination of the parallel component of the momentum equation and the energy balance equation, in one-dimensional Lagrangian coordinates, expresses the parallel dynamics. The internal heat source comes from a kinetic treatment for partial absorption of the parallel heat flux carried by incident plasma electrons streaming through the cloudlet. The nabla B drift drive enters into in the large-R motion in the

  14. Theoretical performance of JP-4 fuel with a 70-30 mixture of fluorine and oxygen as a rocket propellant : equilibrium composition

    NASA Technical Reports Server (NTRS)

    Gordon, Sanford; Huff, Vearl N

    1956-01-01

    Data were calculated for equivalence ratios of 1 to 4, chamber pressures of 300 and 600 pounds per square inch absolute, and pressure ratios of 1 to 1500. Parameters included are specific impulse, combustion and exit temperatures, molecular weight, characteristic velocity, coefficient of thrust, ratio of nozzle-exit area to throat area, specific heat at constant pressure, isentropic exponent, viscosity, and thermal conductivity. A correlation is given which permits determination of performance for a wide range of chamber pressures. A method for obtaining specific impulse of JP-4 fuel with OF2 and O3-F2 mixtures is given.

  15. Modeling the Risk of Fire/Explosion Due to Oxidizer/Fuel Leaks in the Ares I Interstage

    NASA Technical Reports Server (NTRS)

    Ring, Robert W.; Stott, James E.; Hales, Christy

    2008-01-01

    A significant flight hazard associated with liquid propellants, such as those used in the upper stage of NASA's new Ares I launch vehicle, is the possibility of leakage of hazardous fluids resulting in a catastrophic fire/explosion. The enclosed and vented interstage of the Ares I contains numerous oxidizer and fuel supply lines as well as ignition sources. The potential for fire/explosion due to leaks during ascent depends on the relative concentrations of hazardous and inert fluids within the interstage along with other variables such as pressure, temperature, leak rates, and fluid outgasing rates. This analysis improves on previous NASA Probabilistic Risk Assessment (PRA) estimates of the probability of deflagration, in which many of the variables pertinent to the problem were not explicitly modeled as a function of time. This paper presents the modeling methodology developed to analyze these risks.

  16. Response of selected plant and insect species to simulated solid rocket exhaust mixtures and to exhaust components from solid rocket fuels

    NASA Technical Reports Server (NTRS)

    Heck, W. W.; Knott, W. M.; Stahel, E. P.; Ambrose, J. T.; Mccrimmon, J. N.; Engle, M.; Romanow, L. A.; Sawyer, A. G.; Tyson, J. D.

    1980-01-01

    The effects of solid rocket fuel (SRF) exhaust on selected plant and and insect species in the Merritt Island, Florida area was investigated in order to determine if the exhaust clouds generated by shuttle launches would adversely affect the native, plants of the Merritt Island Wildlife Refuge, the citrus production, or the beekeeping industry of the island. Conditions were simulated in greenhouse exposure chambers and field chambers constructed to model the ideal continuous stirred tank reactor. A plant exposure system was developed for dispensing and monitoring the two major chemicals in SRF exhaust, HCl and Al203, and for dispensing and monitoring SRF exhaust (controlled fuel burns). Plants native to Merritt Island, Florida were grown and used as test species. Dose-response relationships were determined for short term exposure of selected plant species to HCl, Al203, and mixtures of the two to SRF exhaust.

  17. Trace element partitioning in ashes from boilers firing pure wood or mixtures of solid waste with respect to fuel composition, chlorine content and temperature.

    PubMed

    Saqib, Naeem; Bäckström, Mattias

    2014-12-01

    Trace element partitioning in solid waste (household waste, industrial waste, waste wood chips and waste mixtures) incineration residues was investigated. Samples of fly ash and bottom ash were collected from six incineration facilities across Sweden including two grate fired and four fluidized bed incinerators, to have a variation in the input fuel composition (from pure biofuel to mixture of waste) and different temperature boiler conditions. As trace element concentrations in the input waste at the same facilities have already been analyzed, the present study focuses on the concentration of trace elements in the waste fuel, their distribution in the incineration residues with respect to chlorine content of waste and combustion temperature. Results indicate that Zn, Cu and Pb are dominating trace elements in the waste fuel. Highly volatile elements mercury and cadmium are mainly found in fly ash in all cases; 2/3 of lead also end up in fly ash while Zn, As and Sb show a large variation in distribution with most of them residing in the fly ash. Lithophilic elements such as copper and chromium are mainly found in bottom ash from grate fired facilities while partition mostly into fly ash from fluidized bed incinerators, especially for plants fuelled by waste wood or ordinary wood chips. There is no specific correlation between input concentration of an element in the waste fuel and fraction partitioned to fly ash. Temperature and chlorine content have significant effects on partitioning characteristics by increasing the formation and vaporization of highly volatile metal chlorides. Zinc and cadmium concentrations in fly ash increase with the incineration temperature. PMID:25263218

  18. Trace element partitioning in ashes from boilers firing pure wood or mixtures of solid waste with respect to fuel composition, chlorine content and temperature.

    PubMed

    Saqib, Naeem; Bäckström, Mattias

    2014-12-01

    Trace element partitioning in solid waste (household waste, industrial waste, waste wood chips and waste mixtures) incineration residues was investigated. Samples of fly ash and bottom ash were collected from six incineration facilities across Sweden including two grate fired and four fluidized bed incinerators, to have a variation in the input fuel composition (from pure biofuel to mixture of waste) and different temperature boiler conditions. As trace element concentrations in the input waste at the same facilities have already been analyzed, the present study focuses on the concentration of trace elements in the waste fuel, their distribution in the incineration residues with respect to chlorine content of waste and combustion temperature. Results indicate that Zn, Cu and Pb are dominating trace elements in the waste fuel. Highly volatile elements mercury and cadmium are mainly found in fly ash in all cases; 2/3 of lead also end up in fly ash while Zn, As and Sb show a large variation in distribution with most of them residing in the fly ash. Lithophilic elements such as copper and chromium are mainly found in bottom ash from grate fired facilities while partition mostly into fly ash from fluidized bed incinerators, especially for plants fuelled by waste wood or ordinary wood chips. There is no specific correlation between input concentration of an element in the waste fuel and fraction partitioned to fly ash. Temperature and chlorine content have significant effects on partitioning characteristics by increasing the formation and vaporization of highly volatile metal chlorides. Zinc and cadmium concentrations in fly ash increase with the incineration temperature.

  19. Hazards Induced by Breach of Liquid Rocket Fuel Tanks: Conditions and Risks of Cryogenic Liquid Hydrogen-Oxygen Mixture Explosions

    NASA Technical Reports Server (NTRS)

    Osipov, Viatcheslav; Muratov, Cyrill; Hafiychuk, Halyna; Ponizovskya-Devine, Ekaterina; Smelyanskiy, Vadim; Mathias, Donovan; Lawrence, Scott; Werkheiser, Mary

    2011-01-01

    We analyze the data of purposeful rupture experiments with LOx and LH2 tanks, the Hydrogen-Oxygen Vertical Impact (HOVI) tests that were performed to clarify the ignition mechanisms, the explosive power of cryogenic H2/Ox mixtures under different conditions, and to elucidate the puzzling source of the initial formation of flames near the intertank section during the Challenger disaster. We carry out a physics-based analysis of general explosions scenarios for cryogenic gaseous H2/Ox mixtures and determine their realizability conditions, using the well-established simplified models from the detonation and deflagration theory. We study the features of aerosol H2/Ox mixture combustion and show, in particular, that aerosols intensify the deflagration flames and can induce detonation for any ignition mechanism. We propose a cavitation-induced mechanism of self-ignition of cryogenic H2/Ox mixtures that may be realized when gaseous H2 and Ox flows are mixed with a liquid Ox turbulent stream, as occurred in all HOVI tests. We present an overview of the HOVI tests to make conclusion on the risk of strong explosions in possible liquid rocket incidents and provide a semi-quantitative interpretation of the HOVI data based on aerosol combustion. We uncover the most dangerous situations and discuss the foreseeable risks which can arise in space missions and lead to tragic outcomes. Our analysis relates to only unconfined mixtures that are likely to arise as a result of liquid propellant space vehicle incidents.

  20. Measurements of some parameters of thermal sparks with respect to their ability to ignite aviation fuel/air mixtures

    NASA Technical Reports Server (NTRS)

    Haigh, S. J.; Hardwick, C. J.; Baldwin, R. E.

    1991-01-01

    A method used to generate thermal sparks for experimental purposes and methods by which parameters of the sparks, such as speed, size, and temperature, were measured are described. Values are given of the range of such parameters within these spark showers. Titanium sparks were used almost exclusively, since it is particles of this metal which are found to be ejected during simulation tests to carbon fiber composite (CFC) joints. Tests were then carried out in which titanium sparks and spark showers were injected into JP4/(AVTAG F40) mixtures with air. Single large sparks and dense showers of small sparks were found to be capable of causing ignition. Tests were then repeated using ethylene/air mixtures, which were found to be more easily ignited by thermal sparks than the JP4/ air mixtures.

  1. Study of flame quenching and near-wall combustion of lean burn fuel-air mixture in a catalytically activated spark-ignited lean burn engine

    SciTech Connect

    Nedunchezhian, N.; Dhandapani, S.

    2006-01-01

    A study of the catalytic activation of charge near the combustion chamber wall and of the flame quenching phenomenon was carried out to identify whether flame quenches due to catalytic activation or due to thermal quenching. It was found that (1) the diffusion rate of fuel into the boundary sublayer limits the catalytic surface reaction rate during combustion; (2) the results of the present flame quench model indicate that the flame quenches due to the heat loss to walls, and the depletion of fuel due to the catalyst coated on the combustion chamber walls does not affect flame quenching; (3) the catalysts coated on the combustion chamber surface do not contribute increased hydrocarbon emissions, but actually reduce them; (4) each catalyst has a specific surface temperature, at which the Damkoehler number for surface reaction is unity.

  2. Advanced Systems for Preprocessing and Characterizing Coal-Biomass Mixtures as Next-Generation Fuels and Feedstocks

    SciTech Connect

    Karmis, Michael; Luttrell, Gerald; Ripepi, Nino; Bratton, Robert; Dohm, Erich

    2014-09-30

    The research activities presented in this report are intended to address the most critical technical challenges pertaining to coal-biomass briquette feedstocks. Several detailed investigations were conducted using a variety of coal and biomass feedstocks on the topics of (1) coal-biomass briquette production and characterization, (2) gasification of coal-biomass mixtures and briquettes, (3) combustion of coal-biomass mixtures and briquettes, and (4) conceptual engineering design and economic feasibility of briquette production. The briquette production studies indicate that strong and durable co-firing feedstocks can be produced by co-briquetting coal and biomass resources commonly available in the United States. It is demonstrated that binderless coal-biomass briquettes produced at optimized conditions exhibit very high strength and durability, which indicates that such briquettes would remain competent in the presence of forces encountered in handling, storage and transportation. The gasification studies conducted demonstrate that coal-biomass mixtures and briquettes are exceptional gasification feedstocks, particularly with regard to the synergistic effects realized during devolatilization of the blended materials. The mixture combustion studies indicate that coal-biomass mixtures are exceptional combustion feedstocks, while the briquette combustion study indicates that the use of blended briquettes reduces NOx, CO2, and CO emissions, and requires the least amount of changes in the operating conditions of an existing coal-fired power plant. Similar results were obtained for the physical durability of the pilot-scale briquettes compared to the bench-scale tests. Finally, the conceptual engineering and feasibility analysis study for a commercial-scale briquetting production facility provides preliminary flowsheet and cost simulations to evaluate the various feedstocks, equipment selection and operating parameters.

  3. Small global effect on terrestrial net primary production due to increased fossil fuel aerosol emissions from East Asia since the turn of the century

    PubMed Central

    Rap, A.; Reddington, C. L.; Spracklen, D. V.; Gloor, M.; Buermann, W.

    2016-01-01

    Abstract The global terrestrial carbon sink has increased since the start of this century at a time of growing carbon emissions from fossil fuel burning. Here we test the hypothesis that increases in atmospheric aerosols from fossil fuel burning enhanced the diffuse light fraction and the efficiency of plant carbon uptake. Using a combination of models, we estimate that at global scale changes in light regimes from fossil fuel aerosol emissions had only a small negative effect on the increase in terrestrial net primary production over the period 1998–2010. Hereby, the substantial increases in fossil fuel aerosol emissions and plant carbon uptake over East Asia were effectively canceled by opposing trends across Europe and North America. This suggests that if the recent increase in the land carbon sink would be causally linked to fossil fuel emissions, it is unlikely via the effect of aerosols but due to other factors such as nitrogen deposition or nitrogen‐carbon interactions. PMID:27773953

  4. Novel anisole mixture and gasoline containing the same

    DOEpatents

    Singerman, Gary M.

    1982-01-26

    A novel anisole mixture containing anisole and a mixture of alkyl anisoles and liquid hydrocarbon fuels containing said novel anisole mixture in an amount sufficient to increase the octane number of said liquid fuel composition.

  5. Thermodynamic analysis of a new combined cooling, heat and power system driven by solid oxide fuel cell based on ammonia-water mixture

    NASA Astrophysics Data System (ADS)

    Ma, Shaolin; Wang, Jiangfeng; Yan, Zhequan; Dai, Yiping; Lu, Bingheng

    2011-10-01

    Although a solid oxide fuel cell combined with a gas turbine (SOFC-GT) has good performance, the temperature of exhaust from gas turbine is still relatively high. In order to recover the waste heat of exhaust from the SOFC-GT to enhance energy conversion efficiency as well as to reduce the emissions of greenhouse gases and pollutants, in this study a new combined cooling, heat and power (CCHP) system driven by the SOFC is proposed to perform the trigeneration by using ammonia-water mixture to recover the waste heat of exhaust from the SOFC-GT. The CCHP system, whose main fuel is methane, can generate electricity, cooling effect and heat effect simultaneously. The overall system performance has been evaluated by mathematical models and thermodynamic laws. A parametric analysis is also conducted to examine the effects of some key thermodynamic parameters on the system performance. Results indicate that the overall energy conversion efficiency exceeds 80% under the given conditions, and it is also found that the increasing the fuel flow rate can improve overall energy conversion efficiency, even though both the SOFC efficiency and electricity efficiency decrease. Moreover, with an increased compressor pressure ratio, the SOFC efficiency, electricity efficiency and overall energy conversion efficiency all increase. Ammonia concentration and pressure entering ammonia-water turbine can also affect the CCHP system performance.

  6. Upgrading of consumer characteristics of granulated solid fuel from mixture of low-grade coal and biomass

    NASA Astrophysics Data System (ADS)

    Kuzmina, J. S.; Milovanov, O. Yu; Sinelshchikov, V. A.; Sytchev, G. A.; Zaichenko, V. M.

    2015-11-01

    Effect of torrefaction on consumer characteristics of fuel pellets made of low-grade and agricultural waste is shown. Data on the volatile content, ash content, calorific value and hygroscopicity for initial pellets and pellets, heat-treated at various temperatures are presented. The experimental study of the combustion process of initial and heat-treated pellets showed that torrefaction of pellets leads to a decreasing of the ignition temperature and an increasing of the efficiency of boiler plant.

  7. Chemical kinetic study of the oxidation of a biodiesel-bioethanol surrogate fuel: methyl octanoate-ethanol mixtures.

    PubMed

    Togbé, C; May-Carle, J-B; Dayma, G; Dagaut, P

    2010-03-25

    There is a growing interest for using bioethanol-biodiesel fuel blends in diesel engines but no kinetic data and model for their combustion were available. Therefore, the kinetics of oxidation of a biodiesel-bioethanol surrogate fuel (methyl octanoate-ethanol) was studied experimentally in a jet-stirred reactor at 10 atm and constant residence time, over the temperature range 560-1160 K, and for several equivalence ratios (0.5-2). Concentration profiles of reactants, stable intermediates, and final products were obtained by probe sampling followed by online FTIR, and off-line gas chromatography analyses. The oxidation of this fuel in these conditions was modeled using a detailed chemical kinetic reaction mechanism consisting of 4592 reversible reactions and 1087 species. The proposed kinetic reaction mechanism yielded a good representation of the kinetics of oxidation of this biodiesel-bioethanol surrogate under the JSR conditions. The modeling was used to delineate the reactions triggering the low-temperature oxidation of ethanol important for diesel engine applications.

  8. Chemical kinetic study of the oxidation of a biodiesel-bioethanol surrogate fuel: methyl octanoate-ethanol mixtures.

    PubMed

    Togbé, C; May-Carle, J-B; Dayma, G; Dagaut, P

    2010-03-25

    There is a growing interest for using bioethanol-biodiesel fuel blends in diesel engines but no kinetic data and model for their combustion were available. Therefore, the kinetics of oxidation of a biodiesel-bioethanol surrogate fuel (methyl octanoate-ethanol) was studied experimentally in a jet-stirred reactor at 10 atm and constant residence time, over the temperature range 560-1160 K, and for several equivalence ratios (0.5-2). Concentration profiles of reactants, stable intermediates, and final products were obtained by probe sampling followed by online FTIR, and off-line gas chromatography analyses. The oxidation of this fuel in these conditions was modeled using a detailed chemical kinetic reaction mechanism consisting of 4592 reversible reactions and 1087 species. The proposed kinetic reaction mechanism yielded a good representation of the kinetics of oxidation of this biodiesel-bioethanol surrogate under the JSR conditions. The modeling was used to delineate the reactions triggering the low-temperature oxidation of ethanol important for diesel engine applications. PMID:20235606

  9. Flame acceleration and the development of detonation in fuel-oxygen mixtures at elevated temperatures and pressures.

    PubMed

    Thomas, G O

    2009-04-30

    Experimental measurements of the conditions required for the development of detonation in a 7 mm tube following ignition by a low energy spark are reported. There are then compared to previous experimental propagation limit criterion using theoretical predictions of detonation cell sizes based on a one-dimensional detonation length scale computed using a detailed chemical kinetic scheme. Technical difficulties precluded direct cell size measurements. Ethylene-oxygen and hydrogen-methane-oxygen mixtures were investigated as well as methane-ammonia-oxygen, at initial pressures and temperatures in the ranges 1-7 bar and 293-540 K, respectively. The likelihood of detonation in ethylene-air mixtures in 150 mm and 50mm pipes at ambient initial conditions is also discussed in relation to published cell width data.The results indicate that whilst detonation cell width predictions do not provide a quantitative measure of the conditions for which detonation may develop in a pipe of given diameter, for prescribed initial conditions, predicted detonation cell size data does provide useful qualitative guidance as to possible hazardous compositions, particularly if preliminary experimental safety testing is thought to be necessary. PMID:18782653

  10. Changes in the Basicity and Species on the Surface of Me(OH) 2-SiO 2 ( Me = Ca, Mg, Sr) Mixtures Due to Mechanical Activation

    NASA Astrophysics Data System (ADS)

    Watanabe, Tomoyuki; Liao, Jiefan; Senna, Mamoru

    1995-03-01

    Mechanical activation increased the surface basicity of the alkaline earth hydroxides in the order Sr(OH) 2 > Ca(OH) 2 > Mg(OH) 2, as determined by titration, temperature-programmed, desorption, and FT-IR. The increase and the difference in the basicity between the hydroxides became more significant in the case of grinding Me (OH) 2-SiO 2 mixtures, as a result of mechanochemical interactions between the ingredients. Bidentate adsorption of CO 2, found exclusively on the ground mixture with SiO2, is only explained by the formation of new - Me-O-Si- bonding. This indicates the incipient formation of alkaline earth silicates as a result of charge transfer during grinding.

  11. [Hypoxic gas mixture delivery due to a defective vaporiser manifold: case report, review of the literature and suggested emergency management algorithm].

    PubMed

    Berlet, T

    2014-04-01

    A case of delivery of a hypoxic gas mixture to a patient during total intravenous anesthesia is described. A progressive fall in inspiratory oxygen concentration followed by a drop in oxygen saturation below 90 % occurred during the advanced stages of a hitherto uneventful general anesthesia of a female patient undergoing anterior cervical fusion surgery. A malfunctioning defective rubber seal of a vaporizer manifold was identified as the cause of the gas leak. The leak had not been detected during the preanesthesia leak test. The problem of hypoxic gas mixtures and uncommon leaks in modern anesthesia equipment is discussed. The importance of locating a leak in the high or low pressure circuits is explained. An algorithm for the management of an unexpected decrease of inspiratory oxygen concentration or any other manifestation of a gas leak along with a systematic approach to locating the source of a gas leak is presented. PMID:24584839

  12. A Kinetic Modeling study on the Oxidation of Primary Reference Fuel?Toluene Mixtures Including Cross Reactions between Aromatics and Aliphatics

    SciTech Connect

    Sakai, Y; Miyoshi, A; Koshi, M; Pitz, W J

    2008-01-09

    A detailed chemical kinetic model for the mixtures of Primary Reference Fuel (PRF: n-heptane and iso-octane) and toluene has been proposed. This model is divided into three parts; a PRF mechanism [T. Ogura et al., Energy & Fuels 21 (2007) 3233-3239], toluene sub-mechanism and cross reactions between PRF and toluene. Toluene sub-mechanism includes the low temperature kinetics relevant to engine conditions. A chemical kinetic mechanism proposed by Pitz et al. [Proc. the 2nd Joint Meeting of the U.S. Combust. Institute (2001)] was used as a starting model and modified by updating rate coefficients. Theoretical estimations of rate coefficients were performed for toluene and benzyl radical reactions important at low temperatures. Cross-reactions between alkane, alkene, and aromatics were also included in order to account for the acceleration by the addition of toluene into iso-octane recently found in the shock tube study of the ignition delay [Y. Sakai et al, SAE 2007-01-4014 (2007)]. Validations of the model were performed with existing shock tube and flow tube data. The model well predicts the ignition characteristics of toluene and PRF/Toluene mixtures under the wide range of temperatures (500-1700 K) and pressures (2-50 atm). It is found that reactions of benzyl radical with oxygen molecule determine the reactivity of toluene at low temperature. Although the effect of toluene addition to iso-octane is not fully resolved, the reactions of alkene with benzyl radical have the possibility to account for the kinetic interactions between PRF and toluene.

  13. MnO2 nanotube-Pt/graphene mixture as an ORR catalyst for proton exchange membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Divya, P.; Ramaprabhu, S.

    2013-02-01

    In the present study, MnO2 nanotubes are synthesized by hydrothermal method and Pt/graphene by co reduction of hexachloroplatinic acid and graphite oxide. The formation of MnO2 nanotubes and Pt/graphene are confirmed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy. MnO2 nanotubes are mixed with Pt/graphene is applied as the ORR catalyst in proton exchange membrane fuel cell. The single cell measurement is carried out after fabricating the membrane electrode assembly and polarization curves are recorded at different temperatures and the results are discussed.

  14. Alternatives to Diesel Fuel in California - Fuel Cycle Energy and Emission Effects of Possible Replacements Due to the TAC Diesel Particulate Decision

    SciTech Connect

    Christopher L. Saraicks; Donald M. Rote; Frank Stodolsky; James J. Eberhardt

    2000-05-01

    Limitations on petroleum-based diesel fuel in California could occur pursuant to the 1998 declaration by California's Air Resources Board (CARB) that the particulate matter component of diesel exhaust is a carcinogen, therefore a toxic air contaminant (TAC) subject to the state's Proposition 65. It is the declared intention of CARB not to ban or restrict diesel fuel, per se, at this time. Assuming no total ban, Argonne National Laboratory (ANL) explored two feasible ''mid-course'' strategies, each of which results in some degree of (conventional) diesel displacement. In the first case, with substantial displacement of compression ignition by spark ignition engines, diesel fuel is assumed admissible for ignition assistance as a pilot fuel in natural gas (NG)-powered heavy-duty vehicles. Gasoline demand in California increases by 32.2 million liters (8.5 million gallons) per day overall, about 21 percent above projected 2010 baseline demand. Natural gas demand increases by 13.6 million diesel liter (3.6 million gallon) equivalents per day, about 7 percent above projected (total) consumption level. In the second case, ressionignition engines utilize substitutes for petroleum-based diesel having similar ignition and performance properties. For each case we estimated localized air emission plus generalized greenhouse gas and energy changes. Fuel replacement by di-methyl ether yields the greatest overall reduction in NOx emissions, though all scenarios bring about PM10 reductions relative to the 2010 baseline, with greatest reductions from the first case described above and the least from fuel replacement by Fischer-Tropsch synthetic diesel. Economic implications of vehicle and engine replacement were not formally evaluated.

  15. Alternatives to diesel fuel in California - fuel cycle energy and emission effects of possible replacements due to the TAC diesel particulate decision.

    SciTech Connect

    Saricks, C. L.; Rote, D. M.; Stodolsky, F.; Eberhardt, J. J.

    1999-12-03

    Limitations on petroleum-based diesel fuel in California could occur pursuant to the 1998 declaration by California's Air Resources Board (CARB) that the particulate matter component of diesel exhaust is a carcinogen, therefore a toxic air contaminant (TAC) subject to the state's Proposition 65. It is the declared intention of CARB not to ban or restrict diesel fuel per se, at this time. Assuming no total ban, Argonne National Laboratory (ANL) explored two feasible mid-course strategies, each of which results in some degree of (conventional) diesel displacement. In the first case, with substantial displacement of compression-ignition by spark-ignition engines, diesel fuel is assumed admissible for ignition assistance as a pilot fuel in natural gas (NG)-powered heavy-duty vehicles. Gasoline demand in California increases by 32.2 million liters (8.5 million gallons) per day overall, about 21% above projected 2010 baseline demand. Natural gas demand increases by 13.6 million diesel liter (3.6 million gallon) equivalents per day, about 7% above projected (total) consumption level. In the second case, compression-ignition engines utilize substitutes for petroleum-based diesel having similar ignition and performance properties. For each case the authors estimated localized air emission plus generalized greenhouse gas and energy changes. Fuel replacement by di-methyl ether yields the greatest overall reduction in NOX emissions, though all scenarios bring about PM{sub 10} reductions relative to the 2010 baseline, with greatest reductions from the first case described above and the least from fuel replacement by Fischer-Tropsch synthetic diesel. Economic implications of vehicle and engine replacement were not formally evaluated.

  16. Comparison of quartz tuning forks and AlN-based extensional microresonators for viscosity measurements in oil/fuel mixtures

    NASA Astrophysics Data System (ADS)

    Toledo, J.; Manzaneque, T.; Hernando-García, J.; Vazquez, J.; Ababneh, A.; Seidel, H.; Lapuerta, M.; Sánchez-Rojas, J. L.

    2013-05-01

    In-situ monitoring of the physical properties of liquids is of great interest in the automotive industry. For example, lubricants are subject to dilution with diesel fuel as a consequence of late-injection processes, which are necessary for regenerating diesel particulate filters. This dilution can be determined by tracking the viscosity and the density of the lubricant. Here we report the test of two in-plane movement based resonators to explore their capability to monitor oil dilution with diesel and biodiesel. One of the resonators is the commercially available millimeter-sized quartz tuning fork, working at 32.7 kHz. The second resonator is a state-of-the-art micron-sized AlN-based rectangular plate, actuated in the first extensional mode in the MHz range. Electrical impedance measurements were carried out to characterize the performance of the structures in various liquid media in a wide range of viscosities. These measurements were completed with the development of low-cost electronic circuits to track the resonance frequency and the quality factor automatically, these two parameters allow to obtain the viscosity of various fluids under investigation, as in the case of dilution of lubricant SAE 15W40 and biodiesel.

  17. Improvement of performance in low temperature solid oxide fuel cells operated on ethanol and air mixtures using Cu-ZnO-Al2O3 catalyst layer

    NASA Astrophysics Data System (ADS)

    Morales, M.; Espiell, F.; Segarra, M.

    2015-10-01

    Anode-supported single-chamber solid oxide fuel cells with and without Cu-ZnO-Al2O3 catalyst layers deposited on the anode support have been operated on ethanol and air mixtures. The cells consist of gadolinia-doped ceria electrolyte, Ni-doped ceria anode, and La0.6Sr0.4CoO3-δ-doped ceria cathode. Catalyst layers with different Cu-ZnO-Al2O3 ratios are deposited and sintered at several temperatures. Since the performance of single-chamber fuel cells strongly depends on catalytic properties of electrodes for partial oxidation of ethanol, the cells are electrochemically characterized as a function of the temperature, ethanol-air molar ratio and gas flow rate. In addition, catalytic activities of supported anode, catalytic layer-supported anode and cathode for partial oxidation of ethanol are analysed. Afterwards, the effect of composition and sintering temperature of catalyst layer on the cell performance are determined. The results indicate that the cell performance can be significantly enhanced using catalyst layers of 30:35:35 and 40:30:30 wt.% Cu-ZnO-Al2O3 sintered at 1100 °C, achieving power densities above 50 mW cm-2 under 0.45 ethanol-air ratio at temperatures as low as 450 °C. After testing for 15 h, all cells present a gradual loss of power density, without carbon deposition, which is mainly attributed to the partial re-oxidation of Ni at the anode.

  18. [Optimization of cultivation conditions of chlorate-reducing bacteria Acinetobacter thermotoleranticus C-1 for treatment of sewage from fuel mixtures industry].

    PubMed

    Smirnova, G F

    2006-01-01

    Composition of culture medium for cultivation of chlorate-reducing strain A. thermotoleranticus C-1 has been optimized with the purpose to decontaminate sewage from production of fuel mixtures, match production sewage, including toxical oxygen-containing anions-chlorates, chromates in particular. It has been established that chlorates are not toxical for the studied culture in a wide concentration range. The rate of chlorates reduction by the strain C-1 was 50.4 + 2.3 mg/(l x h). Maximum chlorate reduction displays in the medium containing (mg/1) : ClO3(-) - 700; CrO4(2-) - 4.5; phosphates in the form of HPO4(2-) - 0.5; in the form of H2PO4(-) - 4.5; nitrogen in the form of NH4Cl - 50.0; t - 40 degrees C; albumin - 500. It is shown that the optimal ratio ChPC:N:P in sewage supplied for neutralization should be 80:10:1 for the efficient use of the strain.

  19. End-to-end testing. [to verify electrical equipment failure due to carbon fibers released in aircraft-fuel fires

    NASA Technical Reports Server (NTRS)

    Pride, R. A.

    1979-01-01

    The principle objective of the kinds of demonstration tests that are discussed is to try to verify whether or not carbon fibers that are released by burning composite parts in an aircraft-fuel fires can produce failures in electrical equipment. A secondary objective discussed is to experimentally validate the analytical models for some of the key elements in the risk analysis. The approach to this demonstration testing is twofold: limited end-to-end test are to be conducted in a shock tube; and planning for some large outdoor burn tests is being done.

  20. Stochastic simulation of fission product activity in primary coolant due to fuel rod failures in typical PWRs under power transients

    NASA Astrophysics Data System (ADS)

    Javed Iqbal, M.; Mirza, Nasir M.; Mirza, Sikander M.

    2008-01-01

    During normal operation of PWRs, routine fuel rods failures result in release of radioactive fission products (RFPs) in the primary coolant of PWRs. In this work, a stochastic model has been developed for simulation of failure time sequences and release rates for the estimation of fission product activity in primary coolant of a typical PWR under power perturbations. In the first part, a stochastic approach is developed, based on generation of fuel failure event sequences by sampling the time dependent intensity functions. Then a three-stage model based deterministic methodology of the FPCART code has been extended to include failure sequences and random release rates in a computer code FPCART-ST, which uses state-of-the-art LEOPARD and ODMUG codes as its subroutines. The value of the 131I activity in primary coolant predicted by FPCART-ST code has been found in good agreement with the corresponding values measured at ANGRA-1 nuclear power plant. The predictions of FPCART-ST code with constant release option have also been found to have good agreement with corresponding experimental values for time dependent 135I, 135Xe and 89Kr concentrations in primary coolant measured during EDITHMOX-1 experiments.

  1. Mixture Experiments

    SciTech Connect

    Piepel, Gregory F.

    2007-12-01

    A mixture experiment involves combining two or more components in various proportions or amounts and then measuring one or more responses for the resulting end products. Other factors that affect the response(s), such as process variables and/or the total amount of the mixture, may also be studied in the experiment. A mixture experiment design specifies the combinations of mixture components and other experimental factors (if any) to be studied and the response variable(s) to be measured. Mixture experiment data analyses are then used to achieve the desired goals, which may include (i) understanding the effects of components and other factors on the response(s), (ii) identifying components and other factors with significant and nonsignificant effects on the response(s), (iii) developing models for predicting the response(s) as functions of the mixture components and any other factors, and (iv) developing end-products with desired values and uncertainties of the response(s). Given a mixture experiment problem, a practitioner must consider the possible approaches for designing the experiment and analyzing the data, and then select the approach best suited to the problem. Eight possible approaches include 1) component proportions, 2) mathematically independent variables, 3) slack variable, 4) mixture amount, 5) component amounts, 6) mixture process variable, 7) mixture of mixtures, and 8) multi-factor mixture. The article provides an overview of the mixture experiment designs, models, and data analyses for these approaches.

  2. Studies of Temperature Elevation Due to the Pre-flame Reaction in a Spark-ignition Engine with CARS Temperature Measurements Using Fuels of Various Octane Numbers

    NASA Astrophysics Data System (ADS)

    Choi, Inyong; Chun, Kwang Min; Hahn, Jae Won; Park, Chul-Woung

    The unburned end-gas temperatures in a combustion chamber of a conventional 4-cylinder DOHC spark-ignition engine were measured using the broadband CARS temperature measurement technique. The test engine was fueled with primary reference fuel 80 and gasoline with research octane numbers of 70.9, 83.4, 91.5 and 100.4. The measured CARS temperatures were compared with the adiabatic core temperatures calculated from the measured pressures. Significant heating by pre-flame reaction in the end gas zone was observed in the late part of compression stroke under both knocking and non-knocking conditions. The measured CARS temperatures when the cylinder pressures were above 1400kPa were higher than the calculated adiabatic core temperatures. These results indicate that some exothermic reactions exist in relatively low pressure and temperature regions. The CARS temperatures began to be higher than the adiabatic core temperature when the end-gas temperatures reached 700K. The temperature elevation due to the pre-flame reaction correlated well with the unburned gas CARS temperature for different research octane number fuels tested.

  3. 33 CFR 155.330 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on U.S. non-oceangoing ships.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS Vessel Equipment § 155.330 Oily mixture (bilge...

  4. 33 CFR 155.370 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of 10,000...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... oily mixtures on ships certificated under 46 CFR Chapter I shall meet the requirements of 46 CFR 56.50... approved under paragraph (a) of this section, it must meet current standards in 46 CFR part 162, subpart... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Oily mixture (bilge...

  5. Sooting characteristics of surrogates for jet fuels

    SciTech Connect

    Mensch, Amy; Santoro, Robert J.; Litzinger, Thomas A.; Lee, S.-Y.

    2010-06-15

    Currently, modeling the combustion of aviation fuels, such as JP-8 and JetA, is not feasible due to the complexity and compositional variation of these practical fuels. Surrogate fuel mixtures, composed of a few pure hydrocarbon compounds, are a key step toward modeling the combustion of practical aviation fuels. For the surrogate to simulate the practical fuel, the composition must be designed to reproduce certain pre-designated chemical parameters such as sooting tendency, H/C ratio, autoignition, as well as physical parameters such as boiling range and density. In this study, we focused only on the sooting characteristics based on the Threshold Soot Index (TSI). New measurements of TSI values derived from the smoke point along with other sooting tendency data from the literature have been combined to develop a set of recommended TSI values for pure compounds used to make surrogate mixtures. When formulating the surrogate fuel mixtures, the TSI values of the components are used to predict the TSI of the mixture. To verify the empirical mixture rule for TSI, the TSI values of several binary mixtures of candidate surrogate components were measured. Binary mixtures were also used to derive a TSI for iso-cetane, which had not previously been measured, and to verify the TSI for 1-methylnaphthalene, which had a low smoke point and large relative uncertainty as a pure compound. Lastly, surrogate mixtures containing three components were tested to see how well the measured TSI values matched the predicted values, and to demonstrate that a target value for TSI can be maintained using various components, while also holding the H/C ratio constant. (author)

  6. 33 CFR 155.370 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of 10,000...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... approved under paragraph (a) of this section, it must meet current standards in 46 CFR part 162, subpart... oily mixtures on ships certificated under 46 CFR Chapter I shall meet the requirements of 46 CFR...

  7. 33 CFR 155.370 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of 10,000...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... approved under paragraph (a) of this section, it must meet current standards in 46 CFR part 162, subpart... oily mixtures on ships certificated under 46 CFR Chapter I shall meet the requirements of 46 CFR...

  8. 33 CFR 155.370 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of 10,000...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... approved under paragraph (a) of this section, it must meet current standards in 46 CFR part 162, subpart... oily mixtures on ships certificated under 46 CFR Chapter I shall meet the requirements of 46 CFR...

  9. Fuel compositions

    SciTech Connect

    Zaweski, E.F.; Niebylski, L.M.

    1986-09-23

    This patent describes a distillate fuel for indirect injection compression ignition engines containing at least the combination of (i) organic nitrate ignition accelerator, and (ii) an additive selected from the group consisting of alkenyl substituted succinimide, alkenyl substituted succinamide and mixtures thereof. The alkenyl substituent contains about 12-36 carbon atoms, the additive being made by the process comprising (a) isomerizing the double bond of an ..cap alpha..-olefin containing about 12-36 carbon atoms to obtain a mixture of internal olefins, (b) reacting the mixture of internal olefins with maleic acid, anhydride or ester to obtain an intermediate alkenyl substituted succinic acid, anhydride or ester, and (c) reacting the intermediate with ammonia to form a succinimide, succinamide or mixture thereof. The combination is present in an amount sufficient to minimize the coking characteristics of such fuel, especially throttling nozzle coking in the prechambers or swirl chambers of indirect injection compression ignition engines operated on such fuel.

  10. Parametric studies with an atmospheric diffusion model that assesses toxic fuel hazards due to the ground clouds generated by rocket launches

    NASA Technical Reports Server (NTRS)

    Stewart, R. B.; Grose, W. L.

    1975-01-01

    Parametric studies were made with a multilayer atmospheric diffusion model to place quantitative limits on the uncertainty of predicting ground-level toxic rocket-fuel concentrations. Exhaust distributions in the ground cloud, cloud stabilized geometry, atmospheric coefficients, the effects of exhaust plume afterburning of carbon monoxide CO, assumed surface mixing-layer division in the model, and model sensitivity to different meteorological regimes were studied. Large-scale differences in ground-level predictions are quantitatively described. Cloud alongwind growth for several meteorological conditions is shown to be in error because of incorrect application of previous diffusion theory. In addition, rocket-plume calculations indicate that almost all of the rocket-motor carbon monoxide is afterburned to carbon dioxide CO2, thus reducing toxic hazards due to CO. The afterburning is also shown to have a significant effect on cloud stabilization height and on ground-level concentrations of exhaust products.

  11. Solid fuel applications to transportation engines

    SciTech Connect

    Rentz, Richard L.; Renner, Roy A.

    1980-06-01

    The utilization of solid fuels as alternatives to liquid fuels for future transportation engines is reviewed. Alternative liquid fuels will not be addressed nor will petroleum/solid fuel blends except for the case of diesel engines. With respect to diesel engines, coal/oil mixtures will be addressed because of the high interest in this specific application as a result of the large number of diesel engines currently in transportation use. Final assessments refer to solid fuels only for diesel engines. The technical assessments of solid fuels utilization for transportation engines is summarized: solid fuel combustion in transportation engines is in a non-developed state; highway transportation is not amenable to solid fuels utilization due to severe environmental, packaging, control, and disposal problems; diesel and open-cycle gas turbines do not appear worthy of further development, although coal/oil mixtures for slow speed diesels may offer some promise as a transition technology; closed-cycle gas turbines show some promise for solid fuels utilization for limited applications as does the Stirling engine for use of cleaner solid fuels; Rankine cycle engines show good potential for limited applications, such as for locomotives and ships; and any development program will require large resources and sophisticated equipment in order to advance the state-of-the-art.

  12. Carcinogenic mixtures.

    PubMed

    Krewski, D; Thomas, R D

    1992-03-01

    Human populations are generally exposed simultaneously to a number of toxicants present in the environment, including complex mixtures of unknown and variable origin. While scientific methods for evaluating the potential carcinogenic risks of pure compounds are relatively well established, methods for assessing the risks of complex mixtures are somewhat less developed. This article provides a report of a recent workshop on carcinogenic mixtures sponsored by the Committee on Toxicology of the U.S. National Research Council, in which toxicological, epidemiological, and statistical approaches to carcinogenic risk assessment for mixtures were discussed. Complex mixtures, such as diesel emissions and tobacco smoke, have been shown to have carcinogenic potential. Bioassay-directed fractionation based on short-term screening test for genotoxicity has also been used in identifying carcinogenic components of mixtures. Both toxicological and epidemiological studies have identified clear interactions between chemical carcinogens, including synergistic effects at moderate to high doses. To date, laboratory studies have demonstrated over 900 interactions involving nearly 200 chemical carcinogens. At lower doses, theoretical arguments suggest that risks may be near additive. Thus, additivity at low doses has been invoked as as a working hypothesis by regulatory authorities in the absence of evidence to the contrary. Future studies of the joint effects of carcinogenic agents may serve to elucidate the mechanisms by which interactions occur at higher doses.

  13. Modeling of molten-fuel-moderator interactions

    NASA Astrophysics Data System (ADS)

    Diab, Aya K.

    CANDU reactors are pressurized heavy-water moderated and cooled reactor designs. During commissioning of nuclear power plants a range of possible accidents must be considered to assure the plants' robust design. Consider a complete channel blockage in the CANDU reactor. Such an extreme flow blockage event would result in fuel overheating, pressure tube failure, partial melting of fuel rods and possible molten fuel-moderator interactions (MFMI). The MFMI phenomenon would occur immediately after tube rupture, and would involve a mixture of steam, hydrogen and molten fuel being ejected into the surrounding moderator water in the form of a high-pressure vapor bubble mixture. This bubble mixture would accelerate the surrounding denser water, causing interfacial mixing due to hydrodynamic instabilities at the interface. As a result of these interfacial instabilities, water is entrained into the growing two-phase bubble mixture with the attendant mass and heat transfer; e.g., water vaporization, fuel oxidation. A comprehensive model is developed to investigate these complex phenomena resulting from a postulated complete flow blockage and complete pressure tube failure. This dynamic model serves as a baseline to characterize the pressure response due to a pressure tube rupture and the associated MFMI phenomena. Theoretical modeling of these interrelated complex phenomena is not known a priori and therefore a semi-empirical approach is adopted. Consequently, experimental work is being proposed as part of the thesis work to verify key hypotheses regarding these interfacial fluid instabilities, such as the entrainment fraction into the rapidly expanding bubble.

  14. Modeling Molten-Fuel-Moderator Interactions

    NASA Astrophysics Data System (ADS)

    Diab, Aya

    2005-11-01

    CANDU reactors are pressurized heavy-water moderated and cooled nuclear reactor designs. During commissioning of nuclear power plants a range of possible accidents must be considered to assure the plants' robust design. One must consider a complete channel blockage in the CANDU reactor. Such an extreme flow blockage event would result in fuel overheating, pressure tube failure, partial melting of fuel rods and possible molten fuel-moderator interactions (MFMI). The MFMI phenomenon would occur immediately following tube rupture, and involves a mixture of steam, hydrogen and molten fuel being ejected into the surrounding moderator water in the form of a high-pressure vapor bubble mixture. This bubble mixture would accelerate the surrounding denser water, causing interfacial mixing due to hydrodynamic instabilities at the interface. As a result of these interfacial instabilities, water is entrained into the growing two-phase bubble mixture with the attendant mass and heat transfer; e.g., water vaporization, fuel oxidation. A comprehensive model has been developed to investigate the complex phenomena resulting from a postulated complete flow blockage and pressure tube failure. This dynamic model will serve as a baseline to characterize the pressure response due to a pressure tube rupture and the associated MFMI phenomena.

  15. Utilization of the heat of catalytic combustion of low-calorie gaseous fuel mixtures by reversing the direction of their input

    SciTech Connect

    Boreskov, G.K.; Ivanov, A.G.; Matros, Y.S.

    1986-05-01

    In the recovery and processing of various industrial raw materials, gas-air mixtures are formed which contain small quantities of carbon monoxide, methane, and other combustible substances. This paper proposes and discusses a method of obtaining high-level heat from these low concentration gases. A nonsteady-state method is proposed in which the reaction mixture is fed at low temperature into a reactor and onto an initially warmed-up stationary catalyst bed; the direction of the feed is periodically reversed. This process forms a slowly migrating front of an exothermic chemical reaction in the bed.

  16. Neutronics Benchmarks for the Utilization of Mixed-Oxide Fuel: Joint U.S./ Russian Progress Report for Fiscal Year 1997, Volume 4, Part 8 - Neutron Poison Plates in Assemblies Containing Homogeneous Mixtures of Polystyrene-Moderated Plutonium and Uranium Oxides

    SciTech Connect

    Yavuz, M.

    1999-05-01

    In the 1970s at the Battelle Pacific Northwest Laboratory (PNL), a series of critical experiments using a remotely operated Split-Table Machine was performed with homogeneous mixtures of (Pu-U)O{sub 2}-polystyrene fuels in the form of square compacts having different heights. The experiments determined the critical geometric configurations of MOX fuel assemblies with and without neutron poison plates. With respect to PuO{sub 2} content and moderation [H/(Pu+U)atomic] ratio (MR), two different homogeneous (Pu-U) O{sub 2}-polystyrene mixtures were considered: Mixture (1) 14.62 wt% PuO{sub 2} with 30.6 MR, and Mixture (2) 30.3 wt% PuO{sub 2} with 2.8 MR. In all mixtures, the uranium was depleted to about O.151 wt% U{sup 235}. Assemblies contained copper, copper-cadmium or aluminum neutron poison plates having thicknesses up to {approximately}2.5 cm. This evaluation contains 22 experiments for Mixture 1, and 10 for Mixture 2 compacts. For Mixture 1, there are 10 configurations with copper plates, 6 with aluminum, and 5 with copper-cadmium. One experiment contained no poison plate. For Mixture 2 compacts, there are 3 configurations with copper, 3 with aluminum, and 3 with copper-cadmium poison plates. One experiment contained no poison plate.

  17. 33 CFR 155.370 - Oily mixture (bilge slops)/fuel oil tank ballast water discharges on oceangoing ships of 10,000...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... approved under paragraph (a) of this section, it must meet current standards in 46 CFR part 162, subpart... oily mixtures on ships certificated under 46 CFR Chapter I shall meet the requirements of 46 CFR 56.50....370 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)...

  18. Alternative jet aircraft fuels

    NASA Technical Reports Server (NTRS)

    Grobman, J.

    1979-01-01

    Potential changes in jet aircraft fuel specifications due to shifts in supply and quality of refinery feedstocks are discussed with emphasis on the effects these changes would have on the performance and durability of aircraft engines and fuel systems. Combustion characteristics, fuel thermal stability, and fuel pumpability at low temperature are among the factors considered. Combustor and fuel system technology needs for broad specification fuels are reviewed including prevention of fuel system fouling and fuel system technology for fuels with higher freezing points.

  19. Laminar flame speeds of moist syngas mixtures

    SciTech Connect

    Das, Apurba K.; Kumar, Kamal; Sung, Chih-Jen

    2011-02-15

    This work experimentally investigates the effect of the presence of water vapor on the laminar flame speeds of moist syngas/air mixtures using the counterflow twin-flame configuration. The experimental results presented here are for fuel lean syngas mixtures with molar percentage of hydrogen in the hydrogen and carbon monoxide mixture varying from 5% to 100%, for an unburned mixture temperature of 323 K, and under atmospheric pressure. At a given equivalence ratio, the effect of varying amount of water vapor addition on the measured laminar flame speed is demonstrated. The experimental laminar flame speeds are also compared with computed values using chemical kinetic mechanisms reported in the literature. It is found that laminar flame speed varies non-monotonically with addition of water for the carbon monoxide rich mixtures. It first increases with increasing amount of water addition, reaches a maximum value, and then decreases. An integrated reaction path analysis is further conducted to understand the controlling mechanism responsible for the non-monotonic variation in laminar flame speed due to water addition. On the other hand, for higher values of H{sub 2}/CO ratio the laminar flame speed monotonically decreases with increasing water addition. It is shown that the competition between the chemical and thermal effects of water addition leads to the observed response. Furthermore, reaction rate sensitivity analysis as well as binary diffusion coefficient sensitivity analysis are conducted to identify the possible sources of discrepancy between the experimental and predicted values. The sensitivity results indicate that the reaction rate constant of H{sub 2}+OH = H{sub 2}O+H is worth revisiting and refinement of binary diffusion coefficient data of N{sub 2}-H{sub 2}O, N{sub 2}-H{sub 2}, and H{sub 2}-H{sub 2}O pairs can be considered. (author)

  20. Small global effect on terrestrial net primary production due to increased fossil fuel aerosol emissions from East Asia during the last decade.

    NASA Astrophysics Data System (ADS)

    O'Sullivan, Michael; Rap, Alex; Reddington, Carly; Spracklen, Dominick; Buermann, Wolfgang

    2016-04-01

    The global terrestrial carbon sink has increased since the start of this century at a time of rapidly growing carbon dioxide emissions from fossil fuel burning. Here we test the hypothesis that increases in atmospheric aerosols from fossil fuel burning have increased the diffuse fraction of incoming solar radiation and the efficiency of photosynthesis leading to increased plant carbon uptake. Using a combination of atmospheric and biospheric models, we find that changes in diffuse light associated with fossil fuel aerosol emission accounts for only 2.8% of the increase in global net primary production (1.221 PgC/yr) over the study period 1998 to 2007. This relatively small global signal is however a result of large regional compensations. Over East Asia, the strong increase in fossil fuel emissions contributed nearly 70% of the increased plant carbon uptake (21 TgC/yr), whereas the declining fossil fuel aerosol emissions in Europe and North America contributed negatively (-16% and -54%, respectively) to increased plant carbon uptake. At global scale, we also find the CO2 fertilization effect on photosynthesis to be the dominant driver of increased plant carbon uptake, in line with previous studies. These results suggest that further research into alternative mechanisms by which fossil fuel emissions could increase carbon uptake, such as nitrogen deposition and carbon-nitrogen interactions, is required to better understand a potential link between the recent changes in fossil fuel emissions and terrestrial carbon uptake.

  1. Variable mixture ratio performance through nitrogen augmentation

    NASA Technical Reports Server (NTRS)

    Beichel, R.; Obrien, C. J.; Bair, E. K.

    1988-01-01

    High/variable mixture ratio O2/H2 candidate engine cycles are examined for earth-to-orbit vehicle application. Engine performance and power balance information are presented for the candidate cycles relative to chamber pressure, bulk density, and mixture ratio. Included in the cycle screening are concepts where a third fluid (liquid nitrogen) is used to achieve a variable mixture ratio over the trajectory from liftoff to earth orbit. The third fluid cycles offer a very low risk, fully reusable, low operation cost alternative to high/variable mixture ratio bipropellant cycles. Variable mixture ratio engines with extendible nozzle are slightly lower performing than a single mixture ratio engine (MR = 7:1) with extendible nozzle. Dual expander engines (MR = 7:1) have slightly better performance than the single mixture ratio engine. Dual fuel dual expander engines offer a 16 percent improvement over the single mixture ratio engine.

  2. A multivariate assessment of innate immune-related gene expressions due to exposure to low concentration individual and mixtures of four kinds of heavy metals on zebrafish (Danio rerio) embryos.

    PubMed

    Cobbina, Samuel Jerry; Xu, Hai; Zhao, Ting; Mao, Guanghua; Zhou, Zhaoxiang; Wu, Xueshan; Liu, Hongyang; Zou, Yanmin; Wu, Xiangyang; Yang, Liuqing

    2015-12-01

    Concerns over the potential health effects of mixtures of low concentration heavy metals on living organisms keep growing by the day. However, the toxicity of low concentration metal mixtures on the immune system of fish species has rarely been investigated. In this study, the zebrafish model was employed to investigate the effect on innate immune and antioxidant-related gene expressions, on exposure to environmentally relevant concentrations of individual and mixtures of Pb (0.01 mg/L), Hg (0.001 mg/L), As (0.01 mg/L) and Cd (0.005 mg/L). Messenger-RNA (mRNA) levels of IL1β, TNF-α, IFNγ, Mx, Lyz, C3B and CXCL-Clc which are closely associated with the innate immune system were affected after exposing zebrafish embryos to metals for 120 h post fertilization (hpf). Individual and mixtures of metals exhibited different potentials to modulate innate-immune gene transcription. IL1β genes were significantly up regulated on exposure to Pb + As (2.01-fold) and inhibited on exposure to Pb + Hg + Cd (0.13-fold). TNF-α was significantly inhibited on exposure to As (0.40-fold) and Pb + As (0.32-fold) compared to control. Metal mixtures generally up regulated IFNγ compared to individual metals. Additionally, antioxidant genes were affected, as CAT and GPx gene expressions generally increased, whiles Mn-SOD and Zn/Cu-SOD reduced. Multivariate analysis showed that exposure to individual metals greatly influenced modulation of innate immune genes; whiles metal mixtures influenced antioxidant gene expressions. This suggests that beside oxidative stress, there may be other pathways influencing gene expressions of innate immune and antioxidant-related genes. Low concentration heavy metals also affect expression of development-related (wnt8a and vegf) genes. Altogether, the results of this study clearly demonstrate that low concentration individual and mixtures of metals in aquatic systems will greatly influence the immune system. It is indicative that mechanisms associated with

  3. A multivariate assessment of innate immune-related gene expressions due to exposure to low concentration individual and mixtures of four kinds of heavy metals on zebrafish (Danio rerio) embryos.

    PubMed

    Cobbina, Samuel Jerry; Xu, Hai; Zhao, Ting; Mao, Guanghua; Zhou, Zhaoxiang; Wu, Xueshan; Liu, Hongyang; Zou, Yanmin; Wu, Xiangyang; Yang, Liuqing

    2015-12-01

    Concerns over the potential health effects of mixtures of low concentration heavy metals on living organisms keep growing by the day. However, the toxicity of low concentration metal mixtures on the immune system of fish species has rarely been investigated. In this study, the zebrafish model was employed to investigate the effect on innate immune and antioxidant-related gene expressions, on exposure to environmentally relevant concentrations of individual and mixtures of Pb (0.01 mg/L), Hg (0.001 mg/L), As (0.01 mg/L) and Cd (0.005 mg/L). Messenger-RNA (mRNA) levels of IL1β, TNF-α, IFNγ, Mx, Lyz, C3B and CXCL-Clc which are closely associated with the innate immune system were affected after exposing zebrafish embryos to metals for 120 h post fertilization (hpf). Individual and mixtures of metals exhibited different potentials to modulate innate-immune gene transcription. IL1β genes were significantly up regulated on exposure to Pb + As (2.01-fold) and inhibited on exposure to Pb + Hg + Cd (0.13-fold). TNF-α was significantly inhibited on exposure to As (0.40-fold) and Pb + As (0.32-fold) compared to control. Metal mixtures generally up regulated IFNγ compared to individual metals. Additionally, antioxidant genes were affected, as CAT and GPx gene expressions generally increased, whiles Mn-SOD and Zn/Cu-SOD reduced. Multivariate analysis showed that exposure to individual metals greatly influenced modulation of innate immune genes; whiles metal mixtures influenced antioxidant gene expressions. This suggests that beside oxidative stress, there may be other pathways influencing gene expressions of innate immune and antioxidant-related genes. Low concentration heavy metals also affect expression of development-related (wnt8a and vegf) genes. Altogether, the results of this study clearly demonstrate that low concentration individual and mixtures of metals in aquatic systems will greatly influence the immune system. It is indicative that mechanisms associated with

  4. Fuel cycle for a fusion neutron source

    NASA Astrophysics Data System (ADS)

    Ananyev, S. S.; Spitsyn, A. V.; Kuteev, B. V.

    2015-12-01

    The concept of a tokamak-based stationary fusion neutron source (FNS) for scientific research (neutron diffraction, etc.), tests of structural materials for future fusion reactors, nuclear waste transmutation, fission reactor fuel production, and control of subcritical nuclear systems (fusion-fission hybrid reactor) is being developed in Russia. The fuel cycle system is one of the most important systems of FNS that provides circulation and reprocessing of the deuterium-tritium fuel mixture in all fusion reactor systems: the vacuum chamber, neutral injection system, cryogenic pumps, tritium purification system, separation system, storage system, and tritium-breeding blanket. The existing technologies need to be significantly upgraded since the engineering solutions adopted in the ITER project can be only partially used in the FNS (considering the capacity factor higher than 0.3, tritium flow up to 200 m3Pa/s, and temperature of reactor elements up to 650°C). The deuterium-tritium fuel cycle of the stationary FNS is considered. The TC-FNS computer code developed for estimating the tritium distribution in the systems of FNS is described. The code calculates tritium flows and inventory in tokamak systems (vacuum chamber, cryogenic pumps, neutral injection system, fuel mixture purification system, isotope separation system, tritium storage system) and takes into account tritium loss in the fuel cycle due to thermonuclear burnup and β decay. For the two facility versions considered, FNS-ST and DEMO-FNS, the amount of fuel mixture needed for uninterrupted operation of all fuel cycle systems is 0.9 and 1.4 kg, consequently, and the tritium consumption is 0.3 and 1.8 kg per year, including 35 and 55 g/yr, respectively, due to tritium decay.

  5. Fuel cycle for a fusion neutron source

    SciTech Connect

    Ananyev, S. S. Spitsyn, A. V. Kuteev, B. V.

    2015-12-15

    The concept of a tokamak-based stationary fusion neutron source (FNS) for scientific research (neutron diffraction, etc.), tests of structural materials for future fusion reactors, nuclear waste transmutation, fission reactor fuel production, and control of subcritical nuclear systems (fusion–fission hybrid reactor) is being developed in Russia. The fuel cycle system is one of the most important systems of FNS that provides circulation and reprocessing of the deuterium–tritium fuel mixture in all fusion reactor systems: the vacuum chamber, neutral injection system, cryogenic pumps, tritium purification system, separation system, storage system, and tritium-breeding blanket. The existing technologies need to be significantly upgraded since the engineering solutions adopted in the ITER project can be only partially used in the FNS (considering the capacity factor higher than 0.3, tritium flow up to 200 m{sup 3}Pa/s, and temperature of reactor elements up to 650°C). The deuterium–tritium fuel cycle of the stationary FNS is considered. The TC-FNS computer code developed for estimating the tritium distribution in the systems of FNS is described. The code calculates tritium flows and inventory in tokamak systems (vacuum chamber, cryogenic pumps, neutral injection system, fuel mixture purification system, isotope separation system, tritium storage system) and takes into account tritium loss in the fuel cycle due to thermonuclear burnup and β decay. For the two facility versions considered, FNS-ST and DEMO-FNS, the amount of fuel mixture needed for uninterrupted operation of all fuel cycle systems is 0.9 and 1.4 kg, consequently, and the tritium consumption is 0.3 and 1.8 kg per year, including 35 and 55 g/yr, respectively, due to tritium decay.

  6. Quantification of Uncertainties due to 235,238U, 239,240,241Pu and Fission Products Nuclear Data Uncertainties for a PWR Fuel Assembly

    NASA Astrophysics Data System (ADS)

    da Cruz, D. F.; Rochman, D.; Koning, A. J.

    2014-04-01

    Uncertainty analysis on reactivity and discharged inventory for a typical PWR fuel element as a result of uncertainties in 235,238U, 239,240,241Pu, and fission products nuclear data was performed. The Total Monte-Carlo (TMC) method was applied using the deterministic transport code DRAGON. The nuclear data used in this study is from the JEFF-3.1 evaluations, with the exception of the nuclear data files for U, Pu and fission products isotopes, which are taken from the nuclear data library TENDL-2012. Results show that the calculated total uncertainty in keff (as result of uncertainties in nuclear data of the considered isotopes) is virtually independent on fuel burnp and amounts to 700 pcm. The uncertainties in inventory of the discharged fuel is dependent on the element considered and lies in the range 1-15% for most fission products, and is below 5% for the most important actinides.

  7. Concentric layer ramjet fuel

    SciTech Connect

    Burdette, G.W.; Francis, J.P.

    1988-03-08

    This patent describes a solid fuel ramjet grain comprising concentric layers of solid ramjet fuel having a perforation therethrough along the center axis of the grain. The performation is connected to a combustion after-chamber. The solid ramjet fuel layers comprises a pure hydroxyl-terminated polybutadiene hydrocarbon fuel or a mixture of a hydroxyl-terminated polybutadiene hydrocarbon fuel and from about 5 to about 60 percent by weight of an additive to increase the fuel regression rate selected from the group consisting of magnesium, boron carbide, aluminum, and zirconium such that, when buried in the operation of the ramjet, each fuel layer produces a different level of thrust.

  8. Method for producing hydrocarbon and alcohol mixtures. [Patent application

    DOEpatents

    Compere, A.L.; Googin, J.M.; Griffith, W.L.

    1980-12-01

    It is an object of this invention to provide an efficient process for extracting alcohols and ketones from an aqueous solution containing the same into hydrocarbon fuel mixtures, such as gasoline, diesel fuel and fuel oil. Another object of the invention is to provide a mixture consisting of hydrocarbon, alcohols or ketones, polyoxyalkylene polymer and water which can be directly added to fuels or further purified. The above stated objects are achieved in accordance with a preferred embodiment of the invention by contacting an aqueous fermentation liquor with a hydrocarbon or hydrocarbon mixture containing carbon compounds having 5 to 18 carbon atoms, which may include gasoline, diesel fuel or fuel oil. The hydrocarbon-aqueous alcohol solution is mixed in the presence or one or more of a group of polyoxyalkylene polymers described in detail hereinafter; the fermentation alcohol being extracted into the hydrocarbon fuel-polyoxyalkylene polymer mixture.

  9. Fuel economizer employing improved turbulent mixing of fuel and air

    SciTech Connect

    Howes, L.D.

    1980-11-25

    A fuel economizer is described for internal combustion engines which increases turbulence of the fuel and air mixture in the carburetor by decreasing the throat of its venturi to a predetermined minimum necessary to induce fuel flow through its fuel jets and then downstream of the venturi adding further atmospheric air for complete combustion.

  10. Uncertainty analysis on reactivity and discharged inventory for a pressurized water reactor fuel assembly due to {sup 235,238}U nuclear data uncertainties

    SciTech Connect

    Da Cruz, D. F.; Rochman, D.; Koning, A. J.

    2012-07-01

    This paper discusses the uncertainty analysis on reactivity and inventory for a typical PWR fuel element as a result of uncertainties in {sup 235,238}U nuclear data. A typical Westinghouse 3-loop fuel assembly fuelled with UO{sub 2} fuel with 4.8% enrichment has been selected. The Total Monte-Carlo method has been applied using the deterministic transport code DRAGON. This code allows the generation of the few-groups nuclear data libraries by directly using data contained in the nuclear data evaluation files. The nuclear data used in this study is from the JEFF3.1 evaluation, and the nuclear data files for {sup 238}U and {sup 235}U (randomized for the generation of the various DRAGON libraries) are taken from the nuclear data library TENDL. The total uncertainty (obtained by randomizing all {sup 238}U and {sup 235}U nuclear data in the ENDF files) on the reactor parameters has been split into different components (different nuclear reaction channels). Results show that the TMC method in combination with a deterministic transport code constitutes a powerful tool for performing uncertainty and sensitivity analysis of reactor physics parameters. (authors)

  11. Systematic approach on the fabrication of Co doped ZnO semiconducting nanoparticles by mixture of fuel approach for Antibacterial applications

    NASA Astrophysics Data System (ADS)

    Rajendar, V.; Dayakar, T.; Shobhan, K.; Srikanth, I.; Venkateswara Rao, K.

    2014-11-01

    Zinc oxide (ZnO) is a wide band gap semiconductor (3.2 eV) with a high exciton binding energy (60 meV), where it has wide applications in advanced spintronic devices. The theoretical prediction of room temperature ferromagnetism and also antibacterial activity will be possible through the investigation of diluted magnetic semiconductors (DMS), such as transition metal doped ZnO, especially Cobalt doped ZnO. The aim of the work is the synthesis of Cobalt (Co) doped ZnO nanopowders were prepared Zn1-xCoxO (0 ⩽ x ⩾ 0.09) nanopowders from Sol-Gel auto combustion method have been synthesized with precursors such as Zinc and Cobalt nitrates with the assistance Ammonium acetate & Urea as fuel by increasing the cobalt concentration in zinc oxide and their structural, morphological, optical, Thermal, magnetic and antibacterial properties were studied by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Transmission Electron microscope (TEM), UV-visible spectroscopy, thermo gravimetric/differential thermal analysis (TG/DTA) and vibrating sample magneto meter (VSM). From the antibacterial studies, against gram positive Bacillus subtilis bacteria is most abundant bacteria in soil and indoor atmosphere, which affects the stored spintronic devices so that the devices should be made with antibacterial activity of DMS like Co doped ZnO. In this article is found that ZnO:Co nanopowders with higher Co doping level (0.07 and 0.09 wt%) exhibit good antibacterial efficiency. The magnetization curves obtained using vibrating sample magnetometer (VSM) show a sign of strong room temperature ferromagnetic behavior when the Co doping level is 0.05 wt% and a weak room temperature ferromagnetic behavior Co doping level is below 0.07 wt%, and also they found to exhibit antiferromagnetic and paramagnetic properties, when the Co doping levels are 0.07 and 0.09 wt%, respectively, to enhance and increase the special magnetic and antibacterial property for

  12. Carburetor fuel discharge assembly

    SciTech Connect

    Yost, R.M.

    1993-06-29

    An improved carburetor for use on an internal combustion engine is described, the carburetor having an airflow passage and fuel discharge means for admitting fuel into the airflow passage for mixing the fuel with air flowing in the airflow passage to form a fuel/air mixture to be supplied to the combustion chamber(s) of the engine, the fuel discharge means including a fuel discharge assembly which comprises a hollow discharge tube and fuel supplying means connected to the discharge tube for admitting fuel into the interior of the discharge tube, wherein the discharge tube has a longitudinal internal bore in fluid communication with the fuel supplying means, wherein the internal bore extends between an inlet that is closest to the fuel supplying means and an outlet that is furthest from the fuel supplying means with the outlet of the bore being located within the airflow passage of the carburetor to supply fuel into this passage after the fuel passes from the fuel supplying means through the internal bore of the discharge tube, wherein the improvement relates to the fuel discharge assembly and comprises: a hollow fuel flow guide tube telescopically received inside the internal bore of the discharge tube, wherein the fuel flow guide tube extends from approximately the location of the inlet of the bore up at least a portion of the length of the bore towards the outlet of the bore to conduct fuel from the fuel supplying means into the bore of the discharge tube.

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

    PubMed

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

    2016-03-01

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

  14. Gas-phase detonation propagation in mixture composition gradients.

    PubMed

    Kessler, D A; Gamezo, V N; Oran, E S

    2012-02-13

    The propagation of detonations through several fuel-air mixtures with spatially varying fuel concentrations is examined numerically. The detonations propagate through two-dimensional channels, inside of which the gradient of mixture composition is oriented normal to the direction of propagation. The simulations are performed using a two-component, single-step reaction model calibrated so that one-dimensional detonation properties of model low- and high-activation-energy mixtures are similar to those observed in a typical hydrocarbon-air mixture. In the low-activation-energy mixture, the reaction zone structure is complex, consisting of curved fuel-lean and fuel-rich detonations near the line of stoichiometry that transition to decoupled shocks and turbulent deflagrations near the channel walls where the mixture is extremely fuel-lean or fuel-rich. Reactants that are not consumed by the leading detonation combine downstream and burn in a diffusion flame. Detonation cells produced by the unstable reaction front vary in size across the channel, growing larger away from the line of stoichiometry. As the size of the channel decreases relative to the size of a detonation cell, the effect of the mixture composition gradient is lessened and cells of similar sizes form. In the high-activation-energy mixture, detonations propagate more slowly as the magnitude of the mixture composition gradient is increased and can be quenched in a large enough gradient. PMID:22213660

  15. Profiling refined hydrocarbon fuels using polar components

    USGS Publications Warehouse

    Rostad, C.E.; Hostettler, F.D.

    2007-01-01

    Identification of a fuel released into the environment can be difficult due to biodegradation or weathering. Negative electrospray ionization/mass spectrometry was used to screen for unique polar components in a wide variety of commercial hydrocarbon products and mixtures. These fuels produced unique and relatively simple spectra. When applied to hydrocarbon samples from a large, long-term fuel spill in a relatively cool climate in which the alkane, isoprenoid, and alkylcyclohexane portions had begun to biodegrade or weather, the polar components in these samples had changed little over time. This technique provided rapid fuel identification on hydrocarbons released into the environment, without sample preparation, fractionation, or chromatography. Copyright ?? Taylor & Francis Group, LLC.

  16. Detailed Kinetic Modeling of Gasoline Surrogate Mixtures

    SciTech Connect

    Mehl, M; Curran, H J; Pitz, W J; Westbrook, C K

    2009-03-09

    Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, a recently revised version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multi-component gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines. Simulation results are discussed focusing attention on the mixing effects of the fuel components.

  17. Fuel cell integrated with steam reformer

    DOEpatents

    Beshty, Bahjat S.; Whelan, James A.

    1987-01-01

    A H.sub.2 -air fuel cell integrated with a steam reformer is disclosed wherein a superheated water/methanol mixture is fed to a catalytic reformer to provide a continuous supply of hydrogen to the fuel cell, the gases exhausted from the anode of the fuel cell providing the thermal energy, via combustion, for superheating the water/methanol mixture.

  18. Antipathogenic activity of probiotics against Salmonella Typhimurium and Clostridium difficile in anaerobic batch culture systems: is it due to synergies in probiotic mixtures or the specificity of single strains?

    PubMed

    Tejero-Sariñena, Sandra; Barlow, Janine; Costabile, Adele; Gibson, Glenn R; Rowland, Ian

    2013-12-01

    Probiotics are currently being investigated for prevention of infections caused by enteric pathogens. The aim of this in vitro study was to evaluate the influence of three single probiotics: Lactobacillus casei NCIMB 30185 (PXN 37), Lactobacillus acidophilus NCIMB 30184 (PXN 35), Bifidobacterium breve NCIMB 30180 (PXN 25) and a probiotic mixture containing the above strains plus twelve other strains belonging to the Lactobacillus, Bifidobacterium, Lactococcus, Streptococcus and Bacillus genera on the survival of Salmonella Typhimurium and Clostridium difficile using pH-controlled anaerobic batch cultures containing mixed faecal bacteria. Changes in relevant bacterial groups and effects of probiotic addition on survival of the two pathogens were assessed over 24 h. Quantitative analysis of bacterial populations revealed that there was a significant increase in lactobacilli and/or bifidobacteria numbers, depending on probiotic addition, compared with the control (no added probiotic). There was also a significant reduction in S. Typhimurium and C. difficile numbers in the presence of certain probiotics compared with controls. Of the probiotic treatments, two single strains namely L. casei NCIMB 30185 (PXN 37), and B. breve NCIMB 30180 (PXN 25) were the most potent in reducing the numbers of S. Typhimurium and C. difficile. In addition, the supplementation with probiotics into the systems influenced some fermentations parameters. Acetate was found in the largest concentrations in all vessels and lactate and formate were generally detected in higher amounts in vessels with probiotic addition compared to controls.

  19. The Gaseous Explosive Reaction : A Study of the Kinetics of Composite Fuels

    NASA Technical Reports Server (NTRS)

    Stevens, F W

    1929-01-01

    This report deals with the results of a series of studies of the kinetics of gaseous explosive reactions where the fuel under observation, instead of being a simple gas, is a known mixture of simple gases. In the practical application of the gaseous explosive reaction as a source of power in the gas engine, the fuels employed are composite, with characteristics that are apt to be due to the characteristics of their components and hence may be somewhat complex. The simplest problem that could be proposed in an investigation either of the thermodynamics or kinetics of the gaseous explosive reaction of a composite fuel would seem to be a separate study of the reaction characteristics of each component of the fuel and then a study of the reaction characteristics of the various known mixtures of those components forming composite fuels more and more complex. (author)

  20. A shift in emission time profiles of fossil fuel combustion due to energy transitions impacts source receptor matrices for air quality.

    PubMed

    Hendriks, Carlijn; Kuenen, Jeroen; Kranenburg, Richard; Scholz, Yvonne; Schaap, Martijn

    2015-03-01

    Effective air pollution and short-lived climate forcer mitigation strategies can only be designed when the effect of emission reductions on pollutant concentrations and health and ecosystem impacts are quantified. Within integrated assessment modeling source-receptor relationships (SRRs) based on chemistry transport modeling are used to this end. Currently, these SRRs are made using invariant emission time profiles. The LOTOS-EUROS model equipped with a source attribution module was used to test this assumption for renewable energy scenarios. Renewable energy availability and thereby fossil fuel back up are strongly dependent on meteorological conditions. We have used the spatially and temporally explicit energy model REMix to derive time profiles for backup power generation. These time profiles were used in LOTOS-EUROS to investigate the effect of emission timing on air pollutant concentrations and SRRs. It is found that the effectiveness of emission reduction in the power sector is significantly lower when accounting for the shift in the way emissions are divided over the year and the correlation of emissions with synoptic situations. The source receptor relationships also changed significantly. This effect was found for both primary and secondary pollutants. Our results indicate that emission timing deserves explicit attention when assessing the impacts of system changes on air quality and climate forcing from short lived substances.

  1. A shift in emission time profiles of fossil fuel combustion due to energy transitions impacts source receptor matrices for air quality.

    PubMed

    Hendriks, Carlijn; Kuenen, Jeroen; Kranenburg, Richard; Scholz, Yvonne; Schaap, Martijn

    2015-03-01

    Effective air pollution and short-lived climate forcer mitigation strategies can only be designed when the effect of emission reductions on pollutant concentrations and health and ecosystem impacts are quantified. Within integrated assessment modeling source-receptor relationships (SRRs) based on chemistry transport modeling are used to this end. Currently, these SRRs are made using invariant emission time profiles. The LOTOS-EUROS model equipped with a source attribution module was used to test this assumption for renewable energy scenarios. Renewable energy availability and thereby fossil fuel back up are strongly dependent on meteorological conditions. We have used the spatially and temporally explicit energy model REMix to derive time profiles for backup power generation. These time profiles were used in LOTOS-EUROS to investigate the effect of emission timing on air pollutant concentrations and SRRs. It is found that the effectiveness of emission reduction in the power sector is significantly lower when accounting for the shift in the way emissions are divided over the year and the correlation of emissions with synoptic situations. The source receptor relationships also changed significantly. This effect was found for both primary and secondary pollutants. Our results indicate that emission timing deserves explicit attention when assessing the impacts of system changes on air quality and climate forcing from short lived substances. PMID:25594282

  2. NEUTRONIC REACTOR FUEL ELEMENT

    DOEpatents

    Picklesimer, M.L.; Thurber, W.C.

    1961-01-01

    A chemically nonreactive fuel composition for incorporation in aluminum- clad, plate type fuel elements for neutronic reactors is described. The composition comprises a mixture of aluminum and uranium carbide particles, the uranium carbide particles containing at least 80 wt.% UC/sub 2/.

  3. Hydrocarbon fuel detergent

    SciTech Connect

    Meyer, G.R.; Lyons, W.R.

    1990-01-23

    This patent describes a hydrocarbon fuel composition comprising: a hydrocarbon fuel; and a detergent amount of a detergent comprising an alkenylsuccinimide prepared by reacting an alkenylsuccinic acid or anhydride with a mixture of amines, wherein at least 90 weight percent of the alkenyl substituent is derived from an olefin having a carbon chain of from 10 to 30 carbons or mixtures thereof, and wherein the alkenylsuccinic acid or anhydride is reacted with the mixture of amines at a mole ratio of 0.8 to 1.5 moles of the amines per mole of the alkenylsuccinic acid or anhydride.

  4. Effect of compositional heterogeneity on dissolution of non-ideal LNAPL mixtures

    NASA Astrophysics Data System (ADS)

    Vasudevan, M.; Johnston, C. D.; Bastow, T. P.; Lekmine, G.; Rayner, J. L.; Nambi, I. M.; Suresh Kumar, G.; Ravi Krishna, R.; Davis, G. B.

    2016-11-01

    The extent of dissolution of petroleum hydrocarbon fuels into groundwater depends greatly on fuel composition. Petroleum fuels can consist of thousands of compounds creating different interactions within the non-aqueous phase liquid (NAPL), thereby affecting the relative dissolution of the components and hence a groundwater plume's composition over long periods. Laboratory experiments were conducted to study the variability in the effective solubilities and activity coefficients for common constituents of gasoline fuels (benzene, toluene, p-xylene and 1,2,4-trimethylbenzene) (BTX) in matrices with an extreme range of molar volumes and chemical affinities. Four synthetic mixtures were investigated comprising BTX with the bulk of the NAPL mixtures made up of either, ethylbenzene (an aromatic like BTX with similar molar volume); 1,3,5-trimethylbenzene (an aromatic with a greater molar volume); n-hexane (an aliphatic with a low molar volume); and n-decane (an aliphatic with a high molar volume). Equilibrium solubility values for the constituents were under-predicted by Raoult's law by up to 30% (higher experimental concentrations) for the mixture with n-hexane as a filler and over-predicted by up to 12% (lower experimental concentrations) for the aromatic mixtures with ethylbenzene and 1,3,5-trimethylbenzene as fillers. Application of PP-LFER (poly-parameter linear free energy relationship) model for non-ideal mixtures also resulted in poor correlation between experimentally measured and predicted concentrations, indicating that differences in chemical affinities can be the major cause of deviation from ideal behavior. Synthetic mixtures were compared with the dissolution behavior of fresh and naturally weathered unleaded gasoline. The presence of lighter aliphatic components in the gasoline had a profound effect on estimating effective solubility due to chemical affinity differences (estimated at 0.0055 per percentage increase in the molar proportion of aliphatic) as

  5. Ionization coefficients in gas mixtures

    NASA Astrophysics Data System (ADS)

    Marić, D.; Šašić, O.; Jovanović, J.; Radmilović-Rađenović, M.; Petrović, Z. Lj.

    2007-03-01

    We have tested the application of the common E/N ( E—electric field, N—gas number density) or Wieland approximation [Van Brunt, R.J., 1987. Common parametrizations of electron transport, collision cross section, and dielectric strength data for binary gas mixtures. J. Appl. Phys. 61 (5), 1773-1787.] and the common mean energy (CME) combination of the data for pure gases to obtain ionization coefficients for mixtures. Test calculations were made for Ar-CH4, Ar-N2, He-Xe and CH4-N2 mixtures. Standard combination procedure gives poor results in general, due to the fact that the electron energy distribution is considerably different in mixtures and in individual gases at the same values of E/N. The CME method may be used for mixtures of gases with ionization coefficients that do not differ by more than two orders of magnitude which is better than any other technique that was proposed [Marić, D., Radmilović-Rađenović, M., Petrović, Z.Lj., 2005. On parametrization and mixture laws for electron ionization coefficients. Eur. Phys. J. D 35, 313-321.].

  6. Autoignition characteristics of aircraft-type fuels

    NASA Technical Reports Server (NTRS)

    Spadaccini, L. J.; Tevelde, J. A.

    1980-01-01

    The ignition delay characteristics of Jet A, JP 4, no. 2 diesel, cetane and an experimental referee broad specification (ERBS) fuel in air at inlet temperatures up to 1000 K, pressures of 10, 15, 20, 25 and 30 atm, and fuel air equivalence ratios of 0.3, 0.5, 0.7 and 1.0 were mapped. Ignition delay times in the range of 1 to 50 msec at freestream flow velocities ranging from 20 to 100 m/sec were obtained using a continuous flow test apparatus which permitted independent variation and evaluation of the effect of temperature, pressure, flow rate, and fuel/air ratio. The ignition delay times for all fuels tested appeared to correlate with the inverse of pressure and the inverse exponent of temperature. With the exception of pure cetane, which had the shortest ignition delay times, the differences between the fuels tested did not appear to be significant. The apparent global activation energies for the typical gas turbine fuels ranged from 38 to 40 kcal/mole, while the activation energy determined for cetane was 50 kcal/mole. In addition, the data indicate that for lean mixtures, ignition delay times decrease with increasing equivalence ratio. It was also noted that physical (apparatus dependent) phenomena, such as mixing (i.e., length and number of injection sites) and airstream cooling (due to fuel heating, vaporization and convective heat loss) can have an important effect on the ignition delay.

  7. Air/fuel ratio controller

    SciTech Connect

    Schechter, M.M.; Simko, A.O.

    1980-12-23

    An internal combustion engine has a fuel injection pump and an air/fuel ratio controller. The controller has a lever that is connected to the pump lever. An aneroid moves the controller lever as a function of changes in intake manifold vacuum to maintain a constant air/fuel ratio to the mixture charge. A fuel enrichment linkage is provided that modifies the movement of the fuel flow control lever by the aneroid in response to changes in manifold gas temperature levels and exhaust gas recirculation to maintain the constant air/fuel ratio. A manual override is provided to obtain a richer air/fuel ratio for maximum acceleration.

  8. Positive and Negative Contributions in the Solvation Enthalpy due to Specific Interactions in Binary Mixtures of C1-C4 n-Alkanols and Chloroform with Butan-2-one.

    PubMed

    Varfolomeev, Mikhail A; Rakipov, Ilnaz T; Solomonov, Boris N; Lodowski, Piotr; Marczak, Wojciech

    2015-06-25

    In the paper, results of calorimetric measurements, IR spectra, and calculated ab initio stabilization energies of dimers are reported for binary systems butan-2-one + (methanol, ethanol, propan-1-ol, butan-1-ol, and chloroform). Changes in the total enthalpy of specific interactions due to dissolution of butan-2-one in the alcohols, calculated using equations derived in previous works, are positive. That results from the endothermic breaking of the O-H···O-H bonds not completely compensated by the exothermic effects of formation of the O-H···O═C ones. Moreover, the concentration of nonbonded molecules of butan-2-one is significant even in dilute solutions, as is evidenced by the shape of the C═O stretching vibrations band in the IR spectra. Apart from that, the spectra do not confirm 1:2 complexes in spite of two lone electron pairs in the carbonyl group of butan-2-one capable of forming the hydrogen bonds. The changes in enthalpy of specific interactions are negative for dilute solutions of alcohols and chloroform in butan-2-one and of butan-2-one in chloroform, because no hydrogen bonds occur in pure butan-2-one. The experimental results are positively correlated with the enthalpies estimated from the ab initio energies using a simple "chemical reaction" approach. PMID:26012694

  9. Positive and Negative Contributions in the Solvation Enthalpy due to Specific Interactions in Binary Mixtures of C1-C4 n-Alkanols and Chloroform with Butan-2-one.

    PubMed

    Varfolomeev, Mikhail A; Rakipov, Ilnaz T; Solomonov, Boris N; Lodowski, Piotr; Marczak, Wojciech

    2015-06-25

    In the paper, results of calorimetric measurements, IR spectra, and calculated ab initio stabilization energies of dimers are reported for binary systems butan-2-one + (methanol, ethanol, propan-1-ol, butan-1-ol, and chloroform). Changes in the total enthalpy of specific interactions due to dissolution of butan-2-one in the alcohols, calculated using equations derived in previous works, are positive. That results from the endothermic breaking of the O-H···O-H bonds not completely compensated by the exothermic effects of formation of the O-H···O═C ones. Moreover, the concentration of nonbonded molecules of butan-2-one is significant even in dilute solutions, as is evidenced by the shape of the C═O stretching vibrations band in the IR spectra. Apart from that, the spectra do not confirm 1:2 complexes in spite of two lone electron pairs in the carbonyl group of butan-2-one capable of forming the hydrogen bonds. The changes in enthalpy of specific interactions are negative for dilute solutions of alcohols and chloroform in butan-2-one and of butan-2-one in chloroform, because no hydrogen bonds occur in pure butan-2-one. The experimental results are positively correlated with the enthalpies estimated from the ab initio energies using a simple "chemical reaction" approach.

  10. Fully ceramic nuclear fuel and related methods

    DOEpatents

    Venneri, Francesco; Katoh, Yutai; Snead, Lance Lewis

    2016-03-29

    Various embodiments of a nuclear fuel for use in various types of nuclear reactors and/or waste disposal systems are disclosed. One exemplary embodiment of a nuclear fuel may include a fuel element having a plurality of tristructural-isotropic fuel particles embedded in a silicon carbide matrix. An exemplary method of manufacturing a nuclear fuel is also disclosed. The method may include providing a plurality of tristructural-isotropic fuel particles, mixing the plurality of tristructural-isotropic fuel particles with silicon carbide powder to form a precursor mixture, and compacting the precursor mixture at a predetermined pressure and temperature.

  11. Interpreting Y chromosome STR haplotype mixture.

    PubMed

    Ge, Jianye; Budowle, Bruce; Chakraborty, Ranajit

    2010-05-01

    Mixture interpretation is a challenging problem in forensic DNA analyses. The interpretation of Y short tandem repeat (STR) haplotype mixtures, due to a lack of recombination, differs somewhat from that of the autosomal DNA markers and is more complex. We describe approaches for calculating the probability of exclusion (PE) and likelihood ratio (LR) methods to interpret Y-STR mixture evidence with population substructure incorporated. For a mixture sample, first, all possible contributor haplotypes in a reference database are listed as a candidate list. The PE is the complement of the summation of the frequencies of haplotypes in the candidate list. The LR method compares the probabilities of the evidence given alternative hypotheses. The hypotheses are possible explanations for the mixture. Population substructure may be further incorporated in likelihood calculation. The maximum number of contributors is based on the candidate list and the computing complexity is polynomial. Additionally, mixtures were simulated by combining two or three 16 Y-STR marker haplotypes derived from the US forensic Y-STR database. The average PE was related to the size of database. With a database comprised of 500 haplotypes an average PE value of at least 0.995 can be obtained for two-person mixtures. The PE decreases with an increasing number of contributors to the mixture. Using the total sample population, the average number of candidate haplotypes of two-person mixtures is 3.73 and 95% mixtures have less than or equal to 10 candidate haplotypes. More than 98.7% of two-person mixtures can only be explained by the haplotype combinations that mixtures are composed. These values are generally higher for three-person mixtures. A small proportion of three-person mixture can also be explained by only two haplotypes.

  12. Neutronic analysis stochastic distribution of fuel particles in Very High Temperature Gas-Cooled Reactors

    NASA Astrophysics Data System (ADS)

    Ji, Wei

    The Very High Temperature Gas-Cooled Reactor (VHTR) is a promising candidate for Generation IV designs due to its inherent safety, efficiency, and its proliferation-resistant and waste minimizing fuel cycle. A number of these advantages stem from its unique fuel design, consisting of a stochastic mixture of tiny (0.78mm diameter) microspheres with multiple coatings. However, the microsphere fuel regions represent point absorbers for resonance energy neutrons, resulting in the "double heterogeneity" for particle fuel. Special care must be taken to analyze this fuel in order to predict the spatial and spectral dependence of the neutron population in a steady-state reactor configuration. The challenges are considerable and resist brute force computation: there are over 1010 microspheres in a typical reactor configuration, with no hope of identifying individual microspheres in this stochastic mixture. Moreover, when individual microspheres "deplete" (e.g., burn the fissile isotope U-235 or transmute the fertile isotope U-238 (eventually) to Pu-239), the stochastic time-dependent nature of the depletion compounds the difficulty posed by the stochastic spatial mixture of the fuel, resulting in a prohibitive computational challenge. The goal of this research is to develop a methodology to analyze particle fuel randomly distributed in the reactor, accounting for the kernel absorptions as well as the stochastic depletion of the fuel mixture. This Ph.D. dissertation will address these challenges by developing a methodology for analyzing particle fuel that will be accurate enough to properly model stochastic particle fuel in both static and time-dependent configurations and yet be efficient enough to be used for routine analyses. This effort includes creation of a new physical model, development of a simulation algorithm, and application to real reactor configurations.

  13. Development of surrogates for aviation jet fuels

    NASA Astrophysics Data System (ADS)

    Nasseri, Seyed Ali

    Surrogate fuels are mixtures of pure hydrocarbons that mimic specific properties of a real fuel. The use of a small number of pure compounds in their formulation ensures that chemical composition is well controlled, helping increase reproducibility of experiments and reduce the computational cost associated with numerical modeling. In this work, surrogate mixtures were developed for Jet A fuel based on correlations between fuel properties (cetane number, smoke point, threshold sooting index (TSI), density, viscosity, boiling point and freezing point) and the nuclear magnetic resonance (NMR) spectra of the fuel as a measure of the fuel's chemical composition. Comparison of the chemical composition and target fuel properties of the surrogate fuels developed in this work to a Jet A fuel sample and other surrogate fuels proposed in the literature revealed the superiority of these surrogate fuels in mimicking the fuel properties of interest.

  14. NUCLEAR FUEL MATERIAL

    DOEpatents

    Goeddel, W.V.

    1962-06-26

    An improved method is given for making the carbides of nuclear fuel material. The metal of the fuel material, which may be a fissile and/or fertile material, is transformed into a silicide, after which the silicide is comminuted to the desired particle size. This silicide is then carburized at an elevated temperature, either above or below the melting point of the silicide, to produce an intimate mixture of the carbide of the fuel material and the carbide of silicon. This mixture of the fuel material carbide and the silicon carbide is relatively stable in the presence of moisture and does not exhibit the highly reactive surface condition which is observed with fuel material carbides made by most other known methods. (AEC)

  15. Fuel Vapor Pressures and the Relation of Vapor Pressure to the Preparation of Fuel for Combustion in Fuel Injection Engines

    NASA Technical Reports Server (NTRS)

    Joachim, William F; Rothrock, A M

    1930-01-01

    This investigation on the vapor pressure of fuels was conducted in connection with the general research on combustion in fuel injection engines. The purpose of the investigation was to study the effects of high temperatures such as exist during the first stages of injection on the vapor pressures of several fuels and certain fuel mixtures, and the relation of these vapor pressures to the preparation of the fuel for combustion in high-speed fuel injection engines.

  16. Influence of propane additives on the detonation characteristics of H2-air mixtures

    NASA Astrophysics Data System (ADS)

    Cheng, Guanbing; Bauer, Pascal; Zitoun, Ratiba

    2014-03-01

    Hydrogen is more and more considered as a potential fuel for propulsion applications. However, due to its low ignition energy and wide flammability limits, H2-air mixtures raise a concern in terms of safety. This aspect can be partly solved by adding an alkane to these mixtures, which plays the role of an inhibitor. The present paper provides data on such binary fuel-air mixtures where various amounts of propane are added to hydrogen. The behavior of the corresponding mixtures, in terms of detonation characteristics and other fundamental properties, such as the cell size of the detonation front and induction delay, are presented and discussed for a series of equivalence ratios and propane addition. The experimental detonation velocity is in good agreement with calculated theoretical Chapman-Jouguet values. Based on soot tracks records, the cell size λ is measured, whereas the induction length L i is derived from data using a GRI-Mech kinetic mechanism. These data allow providing a value of the coefficient K = λ/L i .

  17. Mixture including hydrogen and hydrocarbon having pressure-temperature stability

    NASA Technical Reports Server (NTRS)

    Mao, Wendy L. (Inventor); Mao, Ho-Kwang (Inventor)

    2009-01-01

    The invention relates to a method of storing hydrogen that employs a mixture of hydrogen and a hydrocarbon that can both be used as fuel. In one embodiment, the method involves maintaining a mixture including hydrogen and a hydrocarbon in the solid state at ambient pressure and a temperature in excess of about 10 K.

  18. Facilitated solubilization of polynuclear aromatic hydrocarbons by the cosolvent effect of oxygenated fuel additives and alternative fuels

    SciTech Connect

    Chen, C.S.; Delfino, J.J.

    1996-12-31

    Oxygenated and alternative fuels become popular because three different alternative fuel programs have been mandated in the 1990 Clean Air Act Amendments to minimize combustion-related pollution. The alternative fuels have brought increased interest in the transport and fate of miscible organic liquids in the subsurface and the effect that these liquids have on the transport and fate of other contaminants. The addition of polar organic solvents that are completely miscible or highly soluble in water to a mixture of hydrocarbons and water has the potential of showing the cosolvent effect. Therefore, the use of oxygenated and alternative fuels leads to cosolvency becoming an important issue. The objective of this research is to investigate the redistribution and facilitated transport of hydrophobic organic compounds (HOCs) from contaminated sediment caused by cosolvent effects due to potential oxygenated/alternative fuel spills. Specifically, the phase redistribution of HOCs in aqueous and sediment systems upon the addition of oxygenated and alternative fuels is investigated. This study is expected to provide the basis to predict fate parameters (i.e., dissolution, sorption) for the facilitated transport of HOCs due to cosolvent effects of oxygenated additives and alternative fuels. These fate parameters will allow further assessment of the environmental and health effects of spills and leaks of oxygenated and alternative fuels.

  19. Fuel processing device

    DOEpatents

    Ahluwalia, Rajesh K.; Ahmed, Shabbir; Lee, Sheldon H. D.

    2011-08-02

    An improved fuel processor for fuel cells is provided whereby the startup time of the processor is less than sixty seconds and can be as low as 30 seconds, if not less. A rapid startup time is achieved by either igniting or allowing a small mixture of air and fuel to react over and warm up the catalyst of an autothermal reformer (ATR). The ATR then produces combustible gases to be subsequently oxidized on and simultaneously warm up water-gas shift zone catalysts. After normal operating temperature has been achieved, the proportion of air included with the fuel is greatly diminished.

  20. Minimally refined biomass fuel

    DOEpatents

    Pearson, Richard K.; Hirschfeld, Tomas B.

    1984-01-01

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

  1. The determination of water in biomass-derived liquid fuels

    SciTech Connect

    Roy, C.; De Caumia, B.

    1986-01-01

    The Dean and Stark distillation is an appropriate method for the determination of water in coal tar, bitumen and petroleum-like products. This article shows, however, that a direct application of the Dean and Stark method for the determination of water in biomass-derived liquid fuels results in incorrect estimates. Inaccuracies are due to the presence of soluble organics in the aqueous phase, which apparently form azeotropic mixtures with water and xylene and which condense and are trapped as distillate in the graduated cylinder. Instead, a Karl Fischer determination of water is recommended in the case of biomass-derived liquid fuels.

  2. Turbulent Flame Propagation Characteristics of High Hydrogen Content Fuels

    SciTech Connect

    Seitzman, Jerry; Lieuwen, Timothy

    2014-09-30

    This final report describes the results of an effort to better understand turbulent flame propagation, especially at conditions relevant to gas turbines employing fuels with syngas or hydrogen mixtures. Turbulent flame speeds were measured for a variety of hydrogen/carbon monoxide (H2/CO) and hydrogen/methane (H2/CH4) fuel mixtures with air as the oxidizer. The measurements include global consumption speeds (ST,GC) acquired in a turbulent jet flame at pressures of 1-10 atm and local displacement speeds (ST,LD) acquired in a low-swirl burner at atmospheric pressure. The results verify the importance of fuel composition in determining turbulent flame speeds. For example, different fuel-air mixtures having the same unstretched laminar flame speed (SL,0) but different fuel compositions resulted in significantly different ST,GC for the same turbulence levels (u'). This demonstrates the weakness of turbulent flame speed correlations based simply on u'/SL,0. The results were analyzed using a steady-steady leading points concept to explain the sensitivity of turbulent burning rates to fuel (and oxidizer) composition. Leading point theories suggest that the premixed turbulent flame speed is controlled by the flame front characteristics at the flame brush leading edge, or, in other words, by the flamelets that advance farthest into the unburned mixture (the so-called leading points). For negative Markstein length mixtures, this is assumed to be close to the maximum stretched laminar flame speed (SL,max) for the given fuel-oxidizer mixture. For the ST,GC measurements, the data at a given pressure were well-correlated with an SL,max scaling. However the variation with pressure was not captured, which may be due to non-quasi-steady effects that are not included in the current model. For the ST,LD data, the leading points model again faithfully captured the variation of turbulent flame speed over a wide range of fuel-compositions and turbulence intensities. These results provide

  3. Pulverized coal fuel injector

    DOEpatents

    Rini, Michael J.; Towle, David P.

    1992-01-01

    A pulverized coal fuel injector contains an acceleration section to improve the uniformity of a coal-air mixture to be burned. An integral splitter is provided which divides the coal-air mixture into a number separate streams or jets, and a center body directs the streams at a controlled angle into the primary zone of a burner. The injector provides for flame shaping and the control of NO/NO.sub.2 formation.

  4. Carburetor and fuel preconditioner

    SciTech Connect

    Brown, P.M.

    1991-12-24

    This patent describes an improved carburetor and fuel preconditioner device for internal combustion engines. It comprises a first atmospheric air intake conduit; a bubble chamber operable to hold liquid fuel at a selected level therein, the bubble chamber provided with one or more air ports located below the fuel level for receiving atmospheric air from the first air intake conduit for bubbling air through the fuel and the bubble chamber defining an air-fuel vapor chamber above the fuel level; a multiplicity of catalytic beads located within the bubble chamber in contact with the fuel and with air drawn through the ports; a second atmospheric air intake conduit for receiving an air supply separate from the first conduit, the second conduit provided with at least one venturi, the venturi in fluid communication with the vapor chamber of the bubble chamber for receiving a fuel-air vapor mixture therefrom and for mixing and conducting the same to an intake manifold of the internal combustion engine; and, control means consisting of at least one pill can, located between the vapor chamber of the bubble chamber and the second conduit for controlling the amount of fuel-air mixture entering the second conduit.

  5. Possibility of using alternate fuels in Hungary

    SciTech Connect

    Zombori, J.

    1982-12-01

    In Hungary investigations are aimed at the use of fuel mixtures having a moderate ration of alternate fuels in them. For the last two years engine tests have been carried out with the mixture of diesel oil and sunflower oil, and that of diesel oil and ethanol and they show positive results.

  6. MOLTEN FLUORIDE NUCLEAR REACTOR FUEL

    DOEpatents

    Barton, C.J.; Grimes, W.R.

    1960-01-01

    Molten-salt reactor fuel compositions consisting of mixtures of fluoride salts are reported. In its broadest form, the composition contains an alkali fluoride such as sodium fluoride, zirconium tetrafluoride, and a uranium fluoride, the latter being the tetrafluoride or trifluoride or a mixture of the two. An outstanding property of these fuel compositions is a high coeffieient of thermal expansion which provides a negative temperature coefficient of reactivity in reactors in which they are used.

  7. Monitoring oil-water mixture separation by time domain reflectometry

    NASA Astrophysics Data System (ADS)

    Bruvik, E. M.; Hjertaker, B. T.; Folgerø, K.; Meyer, S. K.

    2012-12-01

    Effective separation of water and oil is an essential part of petroleum production. Time domain reflectometry (TDR) can be used to profile the separation of hydrocarbon oil-water mixtures. In such two-component systems, metal electrodes will become oil-coated due to their affinity to oil. This coating layer will impact water content measurements. By combining the TDR signals from two probes in a novel configuration, the thickness of the oil layer on the electrodes can be estimated and its effect on the TDR measurements corrected for. The probes consist of two rods of different diameter and spacing to a common ground/guard electrode. The measurement principle is demonstrated using a light fuel oil and a thicker organic oil. The results indicate that oil and water levels can be monitored during separation if the metal electrode oil-coating effect is accounted for.

  8. Mixture of Skewed α-Stable Distributions

    NASA Astrophysics Data System (ADS)

    Shojaei, S. R. Hosseini; Nassiri, V.; Mohammadian, Gh. R.; Mohammadpour, A.

    2011-03-01

    Expectation maximization (EM) algorithm and the Bayesian techniques are two approaches for statistical inference of mixture models [3, 4]. By noting the advantages of the Bayesian methods, practitioners prefer them. However, implementing Markov chain Monte Carlo algorithms can be very complicated for stable distributions, due to the non-analytic density or distribution function formulas. In this paper, we introduce a new class of mixture of heavy-tailed distributions, called mixture of skewed stable distributions. Skewed stable distributions belongs to the exponential family and they have analytic density representation. It is shown that skewed stable distributions dominate skew stable distribution functions and they can be used to model heavy-tailed data. The class of skewed stable distributions has an analytic representation for its density function and the Bayesian inference can be done similar to the exponential family of distributions. Finally, mixture of skewed stable distributions are compared to the mixture of stable distributions through a simulations study.

  9. Analysis of interaction in binary odorant mixtures.

    PubMed

    Smith, B H

    1998-12-01

    An understanding of the olfactory system of any animal must account for how odor mixtures are perceived and processed. The present experiments apply associationist models to the study of how elements are processed in binary odorant mixtures. Using experimental designs for Proboscis Extension Conditioning of honey bees, I show that learning about a pure odorant element is frequently affected by its occurrence in a mixture with a second odorant. Presence of a background odor when an odorant is associated with sucrose reinforcement decreases the rate and/or asymptotic level of associative strength that accumulates to that odorant. This interaction is in part due to synthetic qualities that arise in sensory transduction and initial processing. In addition, it involves an attention-like processing system like that involved in overshadowing. Therefore, a model that includes representations of the component and configural qualities of odorants in mixtures is needed to provide a more complete account of learning about odor mixtures. PMID:9877404

  10. Effect of Initial Mixture Temperature on Flame Speed of Methane-Air, Propane-Air, and Ethylene-Air Mixtures

    NASA Technical Reports Server (NTRS)

    Dugger, Gordon L

    1952-01-01

    Flame speeds based on the outer edge of the shadow cast by the laminar Bunsen cone were determined as functions of composition for methane-air mixtures at initial mixture temperatures ranging from -132 degrees to 342 degrees c and for propane-air and ethylene-air mixtures at initial mixture temperatures ranging from -73 degrees to 344 degrees c. The data showed that maximum flame speed increased with temperature at an increasing rate. The percentage change in flame speed with change in initial temperature for the three fuels followed the decreasing order, methane, propane, and ethylene. Empirical equations were determined for maximum flame speed as a function of initial temperature over the temperature range covered for each fuel. The observed effect of temperature on flame speed for each of the fuels was reasonably well predicted by either the thermal theory as presented by Semenov or the square-root law of Tanford and Pease.

  11. 10 CFR 503.9 - Use of mixtures-general requirement for certain permanent exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... and petroleum and an alternate fuel for which an exemption under 10 CFR 503.38 (Fuel mixtures) would... 10 Energy 4 2013-01-01 2013-01-01 false Use of mixtures-general requirement for certain permanent... General Requirements for Exemptions § 503.9 Use of mixtures—general requirement for certain...

  12. 10 CFR 503.9 - Use of mixtures-general requirement for certain permanent exemptions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... and petroleum and an alternate fuel for which an exemption under 10 CFR 503.38 (Fuel mixtures) would... 10 Energy 4 2012-01-01 2012-01-01 false Use of mixtures-general requirement for certain permanent... General Requirements for Exemptions § 503.9 Use of mixtures—general requirement for certain...

  13. 10 CFR 503.9 - Use of mixtures-general requirement for certain permanent exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... and petroleum and an alternate fuel for which an exemption under 10 CFR 503.38 (Fuel mixtures) would... 10 Energy 4 2014-01-01 2014-01-01 false Use of mixtures-general requirement for certain permanent... General Requirements for Exemptions § 503.9 Use of mixtures—general requirement for certain...

  14. 10 CFR 503.9 - Use of mixtures-general requirement for certain permanent exemptions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... and petroleum and an alternate fuel for which an exemption under 10 CFR 503.38 (Fuel mixtures) would... 10 Energy 4 2010-01-01 2010-01-01 false Use of mixtures-general requirement for certain permanent... General Requirements for Exemptions § 503.9 Use of mixtures—general requirement for certain...

  15. 10 CFR 503.9 - Use of mixtures-general requirement for certain permanent exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... and petroleum and an alternate fuel for which an exemption under 10 CFR 503.38 (Fuel mixtures) would... 10 Energy 4 2011-01-01 2011-01-01 false Use of mixtures-general requirement for certain permanent... General Requirements for Exemptions § 503.9 Use of mixtures—general requirement for certain...

  16. Symmetric normal mixtures

    NASA Technical Reports Server (NTRS)

    Turmon, Michael

    2004-01-01

    We consider mixture density estimation under the symmetry constraint x = Az for an orthogonal matrix A. This distributional constraint implies a corresponding constraint on the mixture parameters. Focusing on the gaussian case, we derive an expectation-maximization (EM) algorithm to enforce the constraint and show results for modeling of image feature vectors.

  17. Chemical kinetic modeling of component mixtures relevant to gasoline

    SciTech Connect

    Mehl, M; Curran, H J; Pitz, W J; Dooley, S; Westbrook, C K

    2008-05-29

    Detailed kinetic models of pyrolysis and combustion of hydrocarbon fuels are nowadays widely used in the design of internal combustion engines and these models are effectively applied to help meet the increasingly stringent environmental and energetic standards. In previous studies by the combustion community, such models not only contributed to the understanding of pure component combustion, but also provided a deeper insight into the combustion behavior of complex mixtures. One of the major challenges in this field is now the definition and the development of appropriate surrogate models able to mimic the actual features of real fuels. Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. Their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. Aside the most commonly used surrogates containing iso-octane and n-heptane only, the so called Primary Reference Fuels (PRF), new mixtures have recently been suggested to extend the reference components in surrogate mixtures to also include alkenes and aromatics. It is generally agreed that, including representative species for all the main classes of hydrocarbons which can be found in real fuels, it is possible to reproduce very effectively in a wide range of operating conditions not just the auto-ignition propensity of gasoline or Diesel fuels, but also their physical properties and their combustion residuals [1]. In this work, the combustion behavior of several components relevant to gasoline surrogate formulation is computationally examined. The attention is focused on the autoignition of iso-octane, hexene and their mixtures. Some important issues relevant to the experimental and modeling investigation of such fuels are discussed with the help of rapid compression machine data and calculations. Following the model validation, the behavior of mixtures is discussed on the

  18. Investigation of the intermediate oxidation regime of Diesel fuel

    SciTech Connect

    Al-Hamamre, Z.; Trimis, D.

    2009-09-15

    A very high temperature fuel-air mixture is necessary for the thermal partial oxidation process of hydrocarbon fuels in order to have a high reaction temperature which accelerate the reaction kinetics. For Diesel fuel and due to the ignition delay time behavior, different oxidation behavior can be realized at different preheating temperatures. In this work, the intermediate oxidation region of Diesel fuel is investigated. By making use of the ignition delay time behavior, an vaporizer like tube reactor is constructed in order to enable a very high preheating temperature without the risk of self-ignition in a time-independent experiment. The oxidation behavior of Diesel fuel in air is investigated numerically and experimentally. In the numerical part, the ignition delay time was estimated using CHEMIKIN tools for different air-fuel mixtures at different temperatures. The evaporation behavior of the Diesel fuel-air mixtures are investigated at relatively high air preheating temperatures ranging from 500 C up to 680 C. The amount of the process air was varied from an air ratio {lambda} = 0.35 to {lambda} = 0.6. The experiments are also performed with N{sub 2} as an evaporation media and compared with those performed with air to detect any temperature increase in the case of Diesel-air mixtures. The amount of heat release in the low chemistry region as well as in the intermediate region is calculated for the case of Diesel/air mixtures. The experiments show that four different oxidation region of Diesel fuel can be distinguished depending on air inlet temperatures and on the air ratio. At a temperature lower than 723 K (450 C), no chemical reaction takes place. The cool flame reactions start at temperatures above 723 K (450 C). However, no stable cool flame can be achieved unless the air preheating temperature reached about 753 K (480 C). The cool flame region is extended up to about 873 K (600 C), at which the intermediate regime started. This regime stabilized to a

  19. Experience with coal-water mixtures

    SciTech Connect

    Uhrig, R.E.

    1983-06-01

    A demonstration of coal-water mixture at Florida Power and Light's Sanford plant was a technological success, but not without some difficulty. Extensive accumulation of melted ash, and atomizer wear, made the demonstration only marginal economically. Falling oil prices in 1981-82 made the conversion to COM even less attractive. Combustion tests on the suitability of several candidate coal mixtures concluded that the quantity and characteristics of the ash in the coal is the most important variable in predicting fuel performance. An examination of the characteristics of CWM with various coal-water ratios shows that the ''water penalty'' is not as severe as believed. Yet it is NOT a foregone conclusion that CWM fuels will be economical in the future.

  20. High-temperature sorbent method for removal of sulfur containing gases from gaseous mixtures

    DOEpatents

    Young, J.E.; Jalan, V.M.

    1984-06-19

    A copper oxide-zinc oxide mixture is used as a sorbent for removing hydrogen sulfide and other sulfur containing gases at high temperatures from a gaseous fuel mixture. This high-temperature sorbent is especially useful for preparing fuel gases for high temperature fuel cells. The copper oxide is initially reduced in a preconditioning step to elemental copper and is present in a highly dispersed state throughout the zinc oxide which serves as a support as well as adding to the sulfur sorption capacity. The spent sorbent is regenerated by high-temperature treatment with an air fuel, air steam mixture followed by hydrogen reduction to remove and recover the sulfur.

  1. High-temperature sorbent method for removal of sulfur containing gases from gaseous mixtures

    DOEpatents

    Young, John E.; Jalan, Vinod M.

    1984-01-01

    A copper oxide-zinc oxide mixture is used as a sorbent for removing hydrogen sulfide and other sulfur containing gases at high temperatures from a gaseous fuel mixture. This high-temperature sorbent is especially useful for preparing fuel gases for high temperature fuel cells. The copper oxide is initially reduced in a preconditioning step to elemental copper and is present in a highly dispersed state throughout the zinc oxide which serves as a support as well as adding to the sulfur sorption capacity. The spent sorbent is regenerated by high-temperature treatment with an air fuel, air steam mixture followed by hydrogen reduction to remove and recover the sulfur.

  2. High-temperature sorbent method for removal of sulfur-containing gases from gaseous mixtures

    DOEpatents

    Young, J.E.; Jalan, V.M.

    1982-07-07

    A copper oxide-zinc oxide mixture is used as a sorbent for removing hydrogen sulfide and other sulfur containing gases at high temperatures from a gaseous fuel mixture. This high-temperature sorbent is especially useful for preparing fuel gases for high temperature fuel cells. The copper oxide is initially reduced in a preconditioning step to elemental copper and is present in a highly dispersed state throughout the zinc oxide which serves as a support as well as adding to the sulfur sorbtion capacity. The spent sorbent is regenerated by high-temperature treatment with an air fuel, air steam mixture followed by hydrogen reduction to remove and recover the sulfur.

  3. Fuel cells feasibility

    NASA Technical Reports Server (NTRS)

    Schonfeld, D.; Charng, T.

    1981-01-01

    The technical and economic status of fuel cells is assessed with emphasis on their potential benefits to the Deep Space Network. The fuel cell, what it is, how it operates, and what its outputs are, is reviewed. Major technical problems of the fuel cell and its components are highlighted. Due to these problems and economic considerations it is concluded that fuel cells will not become commercially viable until the early 1990s.

  4. Binder enhanced refuse derived fuel

    DOEpatents

    Daugherty, Kenneth E.; Venables, Barney J.; Ohlsson, Oscar O.

    1996-01-01

    A refuse derived fuel (RDF) pellet having about 11% or more particulate calcium hydroxide which is utilized in a combustionable mixture. The pellets are used in a particulate fuel bring a mixture of 10% or more, on a heat equivalent basis, of the RDF pellet which contains calcium hydroxide as a binder, with 50% or more, on a heat equivalent basis, of a sulphur containing coal. Combustion of the mixture is effective to produce an effluent gas from the combustion zone having a reduced SO.sub.2 and polycyclic aromatic hydrocarbon content of effluent gas from similar combustion materials not containing the calcium hydroxide.

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

    SciTech Connect

    Cooper, John F.; Cherepy, Nerine

    2012-10-09

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

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

    DOEpatents

    Cooper, John F.; Cherepy, Nerine

    2011-08-16

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

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

    DOEpatents

    Cooper, John F.; Cherepy, Nerine

    2012-01-24

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

  8. Carbon Fuel Particles Used in Direct Carbon Conversion Fuel Cells

    DOEpatents

    Cooper, John F.; Cherepy, Nerine

    2008-10-21

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

  9. A numerical study of laminar flames propagating in stratified mixtures

    NASA Astrophysics Data System (ADS)

    Zhang, Jiacheng

    Numerical simulations are carried out to study the structure and speed of laminar flames propagating in compositionally and thermally stratified fuel-air mixtures. The study is motivated by the need to understand the physics of flame propagation in stratified-charge engines and model it. The specific question of interest in this work is: how does the structure and speed of the flame in the stratified mixture differ from that of the flame in a corresponding homogeneous mixture at the same equivalence ratio, temperature, and pressure? The studies are carried out in hydrogen-air, methane-air, and n-heptane-air mixtures. A 30-species 184-step skeletal mechanism is employed for methane oxidation, a 9-species 21-step mechanism for hydrogen oxidation, and a 37-species 56-step skeletal mechanism for n-heptane oxidation. Flame speed and structure are compared with corresponding values for homogeneous mixtures. For compositionally stratified mixtures, as shown in prior experimental work, the numerical results suggest that when the flame propagates from a richer mixture to a leaner mixture, the flame speed is faster than the corresponding speed in the homogeneous mixture. This is caused by enhanced diffusion of heat and species from the richer mixture to the leaner mixture. In fact, the effects become more pronounced in leaner mixtures. Not surprisingly, the stratification gradient influences the results with shallower gradients showing less effect. The controlling role that diffusion plays is further assessed and confirmed by studying the effect of a unity Lewis number assumption in the hydrogen/air mixtures. Furthermore, the effect of stratification becomes less important when using methane or n-heptane as fuel. The laminar flame speed in a thermally stratified mixture is similar to the laminar flame speed in homogeneous mixture at corresponding unburned temperature. Theoretical analysis is performed and the ratio of extra thermal diffusion rate to flame heat release rate

  10. Perception of trigeminal mixtures.

    PubMed

    Filiou, Renée-Pier; Lepore, Franco; Bryant, Bruce; Lundström, Johan N; Frasnelli, Johannes

    2015-01-01

    The trigeminal system is a chemical sense allowing for the perception of chemosensory information in our environment. However, contrary to smell and taste, we lack a thorough understanding of the trigeminal processing of mixtures. We, therefore, investigated trigeminal perception using mixtures of 3 relatively receptor-specific agonists together with one control odor in different proportions to determine basic perceptual dimensions of trigeminal perception. We found that 4 main dimensions were linked to trigeminal perception: sensations of intensity, warmth, coldness, and pain. We subsequently investigated perception of binary mixtures of trigeminal stimuli by means of these 4 perceptual dimensions using different concentrations of a cooling stimulus (eucalyptol) mixed with a stimulus that evokes warmth perception (cinnamaldehyde). To determine if sensory interactions are mainly of central or peripheral origin, we presented stimuli in a physical "mixture" or as a "combination" presented separately to individual nostrils. Results showed that mixtures generally yielded higher ratings than combinations on the trigeminal dimensions "intensity," "warm," and "painful," whereas combinations yielded higher ratings than mixtures on the trigeminal dimension "cold." These results suggest dimension-specific interactions in the perception of trigeminal mixtures, which may be explained by particular interactions that may take place on peripheral or central levels. PMID:25500807

  11. Perception of trigeminal mixtures.

    PubMed

    Filiou, Renée-Pier; Lepore, Franco; Bryant, Bruce; Lundström, Johan N; Frasnelli, Johannes

    2015-01-01

    The trigeminal system is a chemical sense allowing for the perception of chemosensory information in our environment. However, contrary to smell and taste, we lack a thorough understanding of the trigeminal processing of mixtures. We, therefore, investigated trigeminal perception using mixtures of 3 relatively receptor-specific agonists together with one control odor in different proportions to determine basic perceptual dimensions of trigeminal perception. We found that 4 main dimensions were linked to trigeminal perception: sensations of intensity, warmth, coldness, and pain. We subsequently investigated perception of binary mixtures of trigeminal stimuli by means of these 4 perceptual dimensions using different concentrations of a cooling stimulus (eucalyptol) mixed with a stimulus that evokes warmth perception (cinnamaldehyde). To determine if sensory interactions are mainly of central or peripheral origin, we presented stimuli in a physical "mixture" or as a "combination" presented separately to individual nostrils. Results showed that mixtures generally yielded higher ratings than combinations on the trigeminal dimensions "intensity," "warm," and "painful," whereas combinations yielded higher ratings than mixtures on the trigeminal dimension "cold." These results suggest dimension-specific interactions in the perception of trigeminal mixtures, which may be explained by particular interactions that may take place on peripheral or central levels.

  12. Binary Mixtures of Polycyclic Aromatic Hydrocarbons Display Nonadditive Mixture Interactions in an In Vitro Liver Cell Model.

    PubMed

    Gaskill, Stacey J; Bruce, Erica D

    2016-05-01

    Polycyclic aromatic hydrocarbons (PAHs) have been labeled contaminants of concern due to their carcinogenic potential, insufficient toxicological data, environmental ubiquity, and inconsistencies in the composition of environmental mixtures. The Environmental Protection Agency is reevaluating current methods for assessing the toxicity of PAHs, including the assumption of toxic additivity in mixtures. This study was aimed at testing mixture interactions through in vitro cell culture experimentation, and modeling the toxicity using quantitative structure-activity relationships (QSAR). Clone-9 rat liver cells were used to analyze cellular proliferation, viability, and genotoxicity of 15 PAHs in single doses and binary mixtures. Tests revealed that many mixtures have nonadditive toxicity, but display varying mixture effects depending on the mixture composition. Many mixtures displayed antagonism, similar to other published studies. QSARs were then developed using the genetic function approximation algorithm to predict toxic activity both in single PAH congeners and in binary mixtures. Effective concentrations inhibiting 50% of the cell populations were modeled, with R(2) = 0.90, 0.99, and 0.84, respectively. The QSAR mixture algorithms were then adjusted to account for the observed mixture interactions as well as the mixture composition (ratios) to assess the feasibility of QSARs for mixtures. Based on these results, toxic addition is improbable and therefore environmental PAH mixtures are likely to see nonadditive responses when complex interactions occur between components. Furthermore, QSAR may be a useful tool to help bridge these data gaps surrounding the assessment of human health risks that are associated with PAH exposures.

  13. Fuel Processors for PEM Fuel Cells

    SciTech Connect

    Levi T. Thompson

    2008-08-08

    Fuel cells are being developed to power cleaner, more fuel efficient automobiles. The fuel cell technology favored by many automobile manufacturers is PEM fuel cells operating with H2 from liquid fuels like gasoline and diesel. A key challenge to the commercialization of PEM fuel cell based powertrains is the lack of sufficiently small and inexpensive fuel processors. Improving the performance and cost of the fuel processor will require the development of better performing catalysts, new reactor designs and better integration of the various fuel processing components. These components and systems could also find use in natural gas fuel processing for stationary, distributed generation applications. Prototype fuel processors were produced, and evaluated against the Department of Energy technical targets. Significant advances were made by integrating low-cost microreactor systems, high activity catalysts, π-complexation adsorbents, and high efficiency microcombustor/microvaporizers developed at the University of Michigan. The microreactor system allowed (1) more efficient thermal coupling of the fuel processor operations thereby minimizing heat exchanger requirements, (2) improved catalyst performance due to optimal reactor temperature profiles and increased heat and mass transport rates, and (3) better cold-start and transient responses.

  14. SEPARATION OF FLUID MIXTURES

    DOEpatents

    Lipscomb, R.; Craig, A.; Labrow, S.; Dunn, J.F.

    1958-10-28

    An apparatus is presented for separating gaseous mixtures by selectively freezing a constituent of the mixture and subsequently separating the frozen gas. The gas mixture is passed through a cylinder fltted with a cooling jacket, causing one gas to freeze on the walls of the cylinder. A set of scraper blades are provided in the interior of the cyllnder, and as the blades oscillate, the frozen gas is scraped to the bottom of the cylinder. Means are provided for the frozen material to pass into a heating chamber where it is vaporized and the product gas collected.

  15. DIESEL FUEL LUBRICATION

    SciTech Connect

    Qu, Jun

    2012-01-01

    The diesel fuel injector and pump systems contain many sliding interfaces that rely for lubrication upon the fuels. The combination of the poor fuel lubricity and extremely tight geometric clearance between the plunger and bore makes the diesel fuel injector vulnerable to scuffing damage that severely limits the engine life. In order to meet the upcoming stricter diesel emission regulations and higher engine efficiency requirements, further fuel refinements that will result in even lower fuel lubricity due to the removal of essential lubricating compounds, more stringent operation conditions, and tighter geometric clearances are needed. These are expected to increase the scuffing and wear vulnerability of the diesel fuel injection and pump systems. In this chapter, two approaches are discussed to address this issue: (1) increasing fuel lubricity by introducing effective lubricity additives or alternative fuels, such as biodiesel, and (2) improving the fuel injector scuffing-resistance by using advanced materials and/or surface engineering processes. The developing status of the fuel modification approach is reviewed to cover topics including fuel lubricity origins, lubricity improvers, alternative fuels, and standard fuel lubricity tests. The discussion of the materials approach is focused on the methodology development for detection of the onset of scuffing and evaluation of the material scuffing characteristics.

  16. Foaming of mixtures of pure hydrocarbons

    NASA Technical Reports Server (NTRS)

    Robinson, J. V.; Woods, W. W.

    1950-01-01

    Mixtures of pure liquid hydrocarbons are capable of foaming. Nine hydrocarbons were mixed in pairs, in all possible combinations, and four proportions of each combination. These mixtures were sealed in glass tubes, and the foaming was tested by shaking. Mixtures of aliphatic with other aliphatic hydrocarbons, or of alkyl benzenes with other alkyl benzenes, did not foam. Mixtures of aliphatic hydrocarbons with alkyl benzenes did foam. The proportions of the mixtures greatly affected the foaming, the maximum foaming of 12 of 20 pairs being at the composition 20 percent aliphatic hydrocarbon, 80 percent alkyl benzene. Six seconds was the maximum foam lifetime of any of these mixtures. Aeroshell 120 lubricating oil was fractionated into 52 fractions and a residue by extraction with acetone in a fractionating extractor. The index of refraction, foam lifetime, color, and viscosity of these fractions were measured. Low viscosity and high index fractions were extracted first. The viscosity of the fractions extracted rose and the index decreased as fractionation proceeded. Foam lifetimes and color were lowest in the middle fractions. Significance is attached to the observation that none of the foam lifetimes of the fractions or residue is as high as the foam lifetime of the original Aeroshell, indicating that the foaming is not due to a particular foaming constituent, but rather to the entire mixture.

  17. Experimental study on thermal hazard of tributyl phosphate-nitric acid mixtures using micro calorimeter technique.

    PubMed

    Sun, Qi; Jiang, Lin; Gong, Liang; Sun, Jin-Hua

    2016-08-15

    During PUREX spent nuclear fuel reprocessing, mixture of tributyl phosphate (TBP) and hydrocarbon solvent are employed as organic solvent to extract uranium in consideration of radiation contaminated safety and resource recycling, meanwhile nitric acid is utilized to dissolve the spent fuel into small pieces. However, once TBP contacts with nitric acid or nitrates above 130°C, a heavy "red oil" layer would occur accompanied by thermal runaway reactions, even caused several nuclear safety accident. Considering nitric acid volatility and weak exothermic detection, C80micro calorimeter technique was used in this study to investigate thermal decomposition of TBP mixed with nitric acid. Results show that the concentration of nitric acid greatly influences thermal hazard of the system by direct reactions. Even with a low heating rate, if the concentration of nitric acid increases due to evaporation of water or improper operations, thermal runaway in the closed system could start at a low temperature. PMID:27136728

  18. Focused Schlieren flow visualization studies of multiple venturi fuel injectors in a high pressure combustor

    NASA Technical Reports Server (NTRS)

    Chun, K. S.; Locke, R. J.; Lee, C. M.; Ratvasky, W. J.

    1994-01-01

    Multiple venturi fuel injectors were used to obtain uniform fuel distributions, better atomization and vaporization in the premixing/prevaporizing section of a lean premixed/prevaporized flame tube combustor. A focused Schlieren system was used to investigate the fuel/air mixing effectiveness of various fuel injection configurations. The Schlieren system was focused to a plane within the flow field of a test section equipped with optical windows. The focused image plane was parallel to the axial direction of the flow and normal to the optical axis. Images from that focused plane, formed by refracted light due to density gradients within the flow field, were filmed with a high-speed movie camera at framing rates of 8,000 frames per second (fps). Three fuel injection concepts were investigated by taking high-speed movies of the mixture flows at various operating conditions. The inlet air temperature was varied from 600 F to 1000 F, and inlet pressures from 80 psia to 150 psia. Jet-A fuel was used typically at an equivalence ratio of 0.5. The intensity variations of the digitized Schlieren images were analytically correlated to spatial density gradients of the mixture flows. Qualitative measurements for degree of mixedness, intensity of mixing, and mixing completion time are shown. Various mixing performance patterns are presented with different configurations of fuel injection points and operating conditions.

  19. Dual-Mode Measurement and Theoretical Analysis of Evaporation Kinetics of Binary Mixtures

    NASA Astrophysics Data System (ADS)

    Song, Hanyu; He, Chi-Ruei; Basdeo, Carl; Li, Ji-Qin; Ye, Dezhuang; Kalonia, Devendra; Li, Si-Yu; Fan, Tai-Hsi

    Theoretical and experimental investigations are presented for the precision measurement of evaporation kinetics of binary mixtures using a quartz crystal resonator. A thin layer of light alcohol mixture including a volatile (methanol) and a much less volatile (1-butanol) components is deployed on top of the resonator. The normal or acoustic mode is to detect the moving liquid-vapor interface due to evaporation with a great spatial precision on the order of microns, and simultaneously the shear mode is used for in-situ detection of point viscosity or concentration of the mixture near the resonator. A one-dimensional theoretical model is developed to describe the underlying mass transfer and interfacial transport phenomena. Along with the modeling results, the transient evaporation kinetics, moving interface, and the stratification of viscosity of the liquid mixture during evaporation are simultaneously measured by the impedance response of the shear and longitudinal waves emitted from the resonator. The system can be used to characterize complicated evaporation kinetics involving multi-component fuels. American Chemical Society Petroleum Research Fund, NSF CMMI-0952646.

  20. Chemical kinetic modeling of component mixtures relevant to gasoline

    SciTech Connect

    Mehl, M; Curran, H J; Pitz, W J; Westbrook, C K

    2009-02-13

    Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, a recently revised version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multi-component gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines. Simulation results are discussed focusing attention on the mixing effects of the fuel components.

  1. Fuel quality combustion analysis

    NASA Technical Reports Server (NTRS)

    Naegeli, D. W.; Moses, C. A.

    1979-01-01

    A high pressure research combustor operating over a wide range of burner inlet conditions was used to determine the effects of fuel molecular structure on soot formation. Six test fuels with equal hydrogen content (12.8%) were blended to stress different molecular components and final boiling points. The fuels containing high concentrations (20%) of polycyclic aromatics and partially saturated polycyclic structures such as tetralin, produced more soot than would be expected from a hydrogen content correlation for typical petroleum based fuels. Fuels containing naphthenes such as decalin agreed with the hydrogen content correlation. The contribution of polycyclic aromatics to soot formation was equivalent to a reduction in fuel hydrogen content of about one percent. The fuel sensitivity to soot formation due to the polycyclic aromatic contribution decreased as burner inlet pressure and fuel/air ratio increased.

  2. Numerical study of detonation transmission in mixtures containing chemical inhibitors

    NASA Astrophysics Data System (ADS)

    Papalexandris, M. V.

    2012-05-01

    In this article, we report on numerical simulations of the evolution of gaseous detonation waves in mixtures that contain chemical inhibitors. In general, these are compounds that consume the radicals that are produced during combustion, thereby inhibiting the exothermic chain-terminating reaction. Also, some of them participate in endothermic reactions, such as dissociation. These properties make them very efficient flame suppressants. In this study, we employ a chemical kinetics model that consists of a three-step chain-branching mechanism for the fuel combustion and a one-step mechanism for the reaction between inhibitor and radicals. Results from both one- and two-dimensional simulations are presented and discussed. It is shown that radical consumption and heat absorption due to the inhibitor's reaction result in longer induction zones. This, in turn, leads to a detachment of the reaction zone from the precursor shock. For small and medium inhibitor concentrations, this detachment is temporary. Eventually, the radical concentration behind the induction zone becomes sufficient to initiate rapid fuel consumption, thus producing pressure waves which reach the precursor shock and re-ignite the detonation. This is followed by large over-pressures and highly irregular oscillations of the shock. Nonetheless, sufficiently high inhibitor concentrations can yield permanent detonation quenching.

  3. The effect of incomplete fuel-air mixing on the lean limit and emissions characteristics of a Lean Prevaporized Premixed (LPP) combustor

    NASA Technical Reports Server (NTRS)

    Santavicca, D. A.; Steinberger, R. L.; Gibbons, K. A.; Citeno, J. V.; Mills, S.

    1993-01-01

    Results are presented from an experimental study of the effect of incomplete fuel-air mixing on the lean limit and emissions characteristics of a lean, prevaporized, premixed (LPP), coaxial mixing tube combustor. Two-dimensional exciplex fluorescence was used to characterize the degree of fuel vaporization and mixing at the combustor inlet under non-combusting conditions. These tests were conducted at a pressure of 4 atm., a temperature of 400 C, a mixer tube velocity of 100 m/sec and an equivalence ratio of .8, using a mixture of tetradecane, 1 methyl naphthalene and TMPD as a fuel simulant. Fuel-air mixtures with two distinct spatial distributions were studied. The exciplex measurements showed that there was a significant amount of unvaporized fuel at the combustor entrance in both cases. One case, however, exhibited a very non-uniform distribution of fuel liquid and vapor at the combustor entrance, i.e., with most of the fuel in the upper half of the combustor tube, while in the other case, both the fuel liquid and vapor were much more uniformly distributed across the width of the combustor entrance. The lean limit and emissions measurements were all made at a pressure of 4 atm. and a mixer tube velocity of 100 m/sec, using Jet A fuel and both fuel-air mixture distributions. Contrary to what was expected, the better mixed case was found to have a substantially leaner operating limit. The two mixture distributions also unexpectedly resulted in comparable NO(x) emissions, for a given equivalence ratio and inlet temperature, however, lower NO(x) emissions were possible in the better mixed case due to its leaner operating limit.

  4. Kinetics of plasma-assisted combustion: effect of non-equilibrium excitation on the ignition and oxidation of combustible mixtures

    NASA Astrophysics Data System (ADS)

    Popov, N. A.

    2016-08-01

    A review of experimental and theoretical investigations of the effect of atomic particles, and electronically and vibrationally excited molecules on the induction delay time and on the shift in the ignition temperature threshold of combustible mixtures is presented. The addition of oxygen and hydrogen atoms to combustible mixtures may cause a significant reduction in the ignition delay time. However, at relatively low initial temperatures, the non-equilibrium effect of the addition of atomic particles in ground electronic states is not pronounced. At the same time, the effect of excited O(1D) atoms on the oxidation and reforming of combustible mixtures is quite significant due to the high rates of reactions of O(1D) atoms with hydrogen and hydrocarbon molecules. In fuel-air mixtures, collisions with O(1D) atoms determine, under certain conditions, the dissociation of hydrocarbon molecules. Singlet oxygen molecules, O2(a1Δ g ), participate both in chain initiation and chain branching reactions, but the effect of O2(a1Δ g ) on the ignition processes is generally less important compared to oxygen atoms. The reactions of vibrationally excited molecules and the processes of VT-relaxation in combustible mixtures are discussed. The production of vibrationally excited N 2(v) molecules in fuel-air mixtures at relatively low electric field is very important. However, at the moment, the effect of the reactions of N 2(v) molecules on the oxidation and ignition of combustible mixtures is not completely clear, and requires further investigation. Therefore, with present knowledge, to reduce the ignition delay time and decrease the temperature threshold of combustive mixtures, the use of gas discharge systems with relatively high E/N values is recommended. In this case the reactions of electronically excited {{\\text{N}}2}≤ft(\\text{A}{}3Σu+,\\text{B}{}3{{\\Pi}g},\\text{C}{}3{{\\Pi}u},\\text{a}{}\\prime 1Σu-\\right) molecules, and atomic particles in ground and

  5. Customized optimization of cellulase mixtures for differently pretreated rice straw.

    PubMed

    Kim, In Jung; Jung, Ju Yeon; Lee, Hee Jin; Park, Hyong Seok; Jung, Young Hoon; Park, Kyungmoon; Kim, Kyoung Heon

    2015-05-01

    Lignocellulose contains a large amount of cellulose but is recalcitrant to enzymatic hydrolysis, which yields sugars for fuels or chemicals. Various pretreatment methods are used to improve the enzymatic digestibility of cellulose in lignocellulose. Depending on the lignocellulose types and pretreatment methods, biomass compositions and physical properties significantly vary. Therefore, customized enzyme mixtures have to be employed for the efficient hydrolysis of pretreated lignocellulose. Here, using three recombinant model enzymes consisting of endoglucanase, cellobiohydrolase, and xylanase with a fixed amount of β-glucosidase, the optimal formulation of enzyme mixtures was designed for two differently pretreated rice straws (acid-pretreated or alkali-pretreated rice straw) by the mixture design methodology. As a result, different optimal compositions for the enzyme mixtures were employed depending on the type of pretreatment of rice straw. These results suggest that customized enzyme mixtures for pretreated lignocellulosic biomass are necessary to obtain increased sugar yields and should be considered in the industrial utilization of lignocellulose. PMID:25547288

  6. Fossil fuels -- future fuels

    SciTech Connect

    1998-03-01

    Fossil fuels -- coal, oil, and natural gas -- built America`s historic economic strength. Today, coal supplies more than 55% of the electricity, oil more than 97% of the transportation needs, and natural gas 24% of the primary energy used in the US. Even taking into account increased use of renewable fuels and vastly improved powerplant efficiencies, 90% of national energy needs will still be met by fossil fuels in 2020. If advanced technologies that boost efficiency and environmental performance can be successfully developed and deployed, the US can continue to depend upon its rich resources of fossil fuels.

  7. Coal-oil mixtures - Their technical and commercial status

    NASA Astrophysics Data System (ADS)

    Viola, M. A.; Botsaris, G. D.

    The commercial and technical status of coal-oil mixtures (COM) are discussed. Although this technology is commerically available and economic incentives for its use exist, it is argued that optimization of fuel properties and the refinement of its production methods to prepare environmentally 'clean' COM will, along with the growing differential between coal and oil prices, increase its viability as an alternative fuel. Some industrial corporations have to date demonstrated preparation facilities and potential applications.

  8. Apparatus for supplementary control of a combustible mixture

    SciTech Connect

    Eheim, F.

    1980-06-03

    A fuel control device for an internal combustion engine employing a fuel mixture preparation system in which the amount of fuel is set at will and the amount of combustion air is adjusted automatically. In order to provide sufficient air during abrupt and rapid actuations of the fuel control lever, there is provided a hydraulic differentiating mechanism which senses rapid displacements of the fuel control lever and which temporarily opens a channel leading from a source of high hydraulic pressure directly to the servo motor that pivots the air throttle, thereby causing additional opening of the air throttle and an increased rate of air flow. The high pressure channel is closed gradually after the occurrence of the abrupt fuel change.

  9. Influence of drop size distribution and fuel vapor fraction on premixed spray combustion

    NASA Astrophysics Data System (ADS)

    Machiroutu, Sridhar Venkatabojji

    Premixed spray combustion is affected by fuel and oxidizer properties, mixture equivalence ratio and spray quality. The spray quality is characterized by a mean droplet diameter (SMD) and a droplet size distribution (DSD). Prior experimental studies have considered only the influence of SMD, in part due to the difficulty in controlling the DSD independently. The present work provides experimental evidence demonstrating the effect of the fuel droplet size distribution and fuel vapor fraction on premixed spray combustion. Combustion experiments were performed in a pilot-ignited, continuous flow, tubular, vertical test rig wherein fuel sprays were injected into an air stream. A novel twin-atomizer technique that allowed control over overall equivalence ratio, SMD, DSD, and fuel vapor fraction of the premixed spray was used to generate test sprays. A line-of-sight, infrared (IR) extinction technique was developed to quantify the fuel vapor fraction in premixed sprays. Radial distributions of fuel vapor were evaluated using an 'onion peeling' deconvolution technique. Combustion of test sprays indicated flame propagation among regions of high fuel vapor fraction to generate a high rate of combustion. In lean premixed sprays, the presence of a low fuel vapor concentration does not impact the combustion process. Experimental evidence demonstrating the enhancement of flame propagation velocity for optimal SMDs of ethanol sprays has been found. It was observed that test sprays with narrower DSDs have faster burning rates and more complete combustion. The DSD of the sprays were characterized with a droplet surface-area-based standard deviation of the DSD.

  10. Laser ablation based fuel ignition

    DOEpatents

    Early, J.W.; Lester, C.S.

    1998-06-23

    There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition. 3 figs.

  11. Laser ablation based fuel ignition

    DOEpatents

    Early, James W.; Lester, Charles S.

    1998-01-01

    There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition.

  12. Transcriptional responses to complex mixtures: a review.

    PubMed

    Sen, Banalata; Mahadevan, Brinda; DeMarini, David M

    2007-01-01

    Exposure of people to hazardous compounds is primarily through complex environmental mixtures, those that occur through media such as air, soil, water, food, cigarette smoke, and combustion emissions. Microarray technology offers the ability to query the entire genome after exposure to such an array of compounds, permitting a characterization of the biological effects of such exposures. This review summarizes the published literature on the transcriptional profiles resulting from exposure of cells or organisms to complex environmental mixtures such as cigarette smoke, diesel emissions, urban air, motorcycle exhaust, carbon black, jet fuel, and metal ore and fumes. The majority of the mixtures generally up-regulate gene expression, with heme oxygenase 1 and CYP1A1 being up-regulated by all of the mixtures. Most of the mixtures altered the expression of genes involved in oxidative stress response (OH-1, metallothioneins), immune/inflammation response (IL-1b, protein kinase), xenobiotic metabolism (CYP1A1, CYP1B1), coagulation and fibrinolysis (plasminogen activator/inhibitor), proto-oncogenes (FUS1, JUN), heat-shock response (HSP60, HSP70), DNA repair (PCNA, GADD45), structural unit of condensed DNA (Crf15Orf16, DUSP 15), and extracellular matrix degradation (MMP1, 8, 9, 11, 12). Genes involved in aldehyde metabolism, such as ALDH3, appeared to be uniquely modulated by cigarette smoke. Cigarette smoke-exposed populations have been successfully distinguished from control nonexposed populations based on the expression pattern of a subset of genes, thereby demonstrating the utility of this approach in identifying biomarkers of exposure and susceptibility. The analysis of gene-expression data at the pathway and functional level, along with a systems biology approach, will provide a more comprehensive insight into the biological effects of complex mixtures and will improve risk assessment of the same. We suggest critical components of study design and reporting that will

  13. Transcriptional responses to complex mixtures: a review.

    PubMed

    Sen, Banalata; Mahadevan, Brinda; DeMarini, David M

    2007-01-01

    Exposure of people to hazardous compounds is primarily through complex environmental mixtures, those that occur through media such as air, soil, water, food, cigarette smoke, and combustion emissions. Microarray technology offers the ability to query the entire genome after exposure to such an array of compounds, permitting a characterization of the biological effects of such exposures. This review summarizes the published literature on the transcriptional profiles resulting from exposure of cells or organisms to complex environmental mixtures such as cigarette smoke, diesel emissions, urban air, motorcycle exhaust, carbon black, jet fuel, and metal ore and fumes. The majority of the mixtures generally up-regulate gene expression, with heme oxygenase 1 and CYP1A1 being up-regulated by all of the mixtures. Most of the mixtures altered the expression of genes involved in oxidative stress response (OH-1, metallothioneins), immune/inflammation response (IL-1b, protein kinase), xenobiotic metabolism (CYP1A1, CYP1B1), coagulation and fibrinolysis (plasminogen activator/inhibitor), proto-oncogenes (FUS1, JUN), heat-shock response (HSP60, HSP70), DNA repair (PCNA, GADD45), structural unit of condensed DNA (Crf15Orf16, DUSP 15), and extracellular matrix degradation (MMP1, 8, 9, 11, 12). Genes involved in aldehyde metabolism, such as ALDH3, appeared to be uniquely modulated by cigarette smoke. Cigarette smoke-exposed populations have been successfully distinguished from control nonexposed populations based on the expression pattern of a subset of genes, thereby demonstrating the utility of this approach in identifying biomarkers of exposure and susceptibility. The analysis of gene-expression data at the pathway and functional level, along with a systems biology approach, will provide a more comprehensive insight into the biological effects of complex mixtures and will improve risk assessment of the same. We suggest critical components of study design and reporting that will

  14. CH-radical concentration measurements in fuel-rich CH{sub 4}/O{sub 2}/Ar and CH{sub 4}/O{sub 2}/NO/Ar mixtures behind shock waves

    SciTech Connect

    Woiki, D.; Votsmeier, M.; Davidson, D.F.; Hanson, R.K.; Bowman, C.T.

    1998-06-01

    CH radicals are important precursors in prompt-NO formation and they also play a role in NO removal via reburning. Little information exists, however, on the absolute concentrations of CH during fuel-rich methane oxidation and their dependence on NO concentrations. Here the authors report results of CH-radical measurements for such conditions, using a shock tube in combination with a sensitive CH absorption diagnostic. These measurements provide useful data for the further development of large-scale reaction mechanisms, such as the recently developed Gas Research Institute methane oxidation and NO reburning mechanism (GRI-Mech 2.11). CH-radical profiles were measured at high temperatures for fuel-rich methane oxidation with and without addition of NO. Comparison of these data with predictions based on the GRI-Mech 2.11 mechanism shows significant deviations, suggesting the need for additional high-temperature rate data on important CH reactions and for further optimization of the detailed mechanism.

  15. Cold start characteristics of ethanol as an automobile fuel

    DOEpatents

    Greiner, Leonard

    1982-01-01

    An alcohol fuel burner and decomposer in which one stream of fuel is preheated by passing it through an electrically heated conduit to vaporize the fuel, the fuel vapor is mixed with air, the air-fuel mixture is ignited and combusted, and the combustion gases are passed in heat exchange relationship with a conduit carrying a stream of fuel to decompose the fuel forming a fuel stream containing hydrogen gas for starting internal combustion engines, the mass flow of the combustion gas being increased as it flows in heat exchange relationship with the fuel carrying conduit, is disclosed.

  16. Secondary fuel delivery system

    DOEpatents

    Parker, David M.; Cai, Weidong; Garan, Daniel W.; Harris, Arthur J.

    2010-02-23

    A secondary fuel delivery system for delivering a secondary stream of fuel and/or diluent to a secondary combustion zone located in the transition piece of a combustion engine, downstream of the engine primary combustion region is disclosed. The system includes a manifold formed integral to, and surrounding a portion of, the transition piece, a manifold inlet port, and a collection of injection nozzles. A flowsleeve augments fuel/diluent flow velocity and improves the system cooling effectiveness. Passive cooling elements, including effusion cooling holes located within the transition boundary and thermal-stress-dissipating gaps that resist thermal stress accumulation, provide supplemental heat dissipation in key areas. The system delivers a secondary fuel/diluent mixture to a secondary combustion zone located along the length of the transition piece, while reducing the impact of elevated vibration levels found within the transition piece and avoiding the heat dissipation difficulties often associated with traditional vibration reduction methods.

  17. Opportunity fuels

    SciTech Connect

    Lutwen, R.C.

    1994-12-31

    Opportunity fuels - fuels that can be converted to other forms of energy at lower cost than standard fossil fuels - are discussed in outline form. The type and source of fuels, types of fuels, combustability, methods of combustion, refinery wastes, petroleum coke, garbage fuels, wood wastes, tires, and economics are discussed.

  18. Fuel nozzle assembly

    DOEpatents

    Johnson, Thomas Edward; Ziminsky, Willy Steve; Lacey, Benjamin Paul; York, William David; Stevenson, Christian Xavier

    2011-08-30

    A fuel nozzle assembly is provided. The assembly includes an outer nozzle body having a first end and a second end and at least one inner nozzle tube having a first end and a second end. One of the nozzle body or nozzle tube includes a fuel plenum and a fuel passage extending therefrom, while the other of the nozzle body or nozzle tube includes a fuel injection hole slidably aligned with the fuel passage to form a fuel flow path therebetween at an interface between the body and the tube. The nozzle body and the nozzle tube are fixed against relative movement at the first ends of the nozzle body and nozzle tube, enabling the fuel flow path to close at the interface due to thermal growth after a flame enters the nozzle tube.

  19. Method and system for low-NO.sub.x dual-fuel combustion of liquid and/or gaseous fuels

    SciTech Connect

    Gard, Vincent; Chojnacki, Dennis A; Rabovitser, Ioseph K

    2014-12-02

    A method and apparatus for combustion in which a pressurized preheated liquid fuel is atomized and a portion thereof flash vaporized, creating a mixture of fuel vapor and liquid droplets. The mixture is mixed with primary combustion oxidant, producing a fuel/primary oxidant mixture which is then injected into a primary combustion chamber in which the fuel/primary oxidant mixture is partially combusted, producing a secondary gaseous fuel containing hydrogen and carbon oxides. The secondary gaseous fuel is mixed with a secondary combustion oxidant and injected into the second combustion chamber wherein complete combustion of the secondary gaseous fuel is carried out. The resulting second stage flue gas containing very low amounts of NO.sub.x is then vented from the second combustion chamber.

  20. Hydrogen-fuel-powered bell segments of biomimetic jellyfish

    NASA Astrophysics Data System (ADS)

    Tadesse, Yonas; Villanueva, Alex; Haines, Carter; Novitski, David; Baughman, Ray; Priya, Shashank

    2012-04-01

    Artificial muscles powered by a renewable energy source are desired for joint articulation in bio-inspired autonomous systems. In this study, a robotic underwater vehicle, inspired by jellyfish, was designed to be actuated by a chemical fuel source. The fuel-powered muscles presented in this work comprise nano-platinum catalyst-coated multi-wall carbon nanotube (MWCNT) sheets, wrapped on the surface of nickel-titanium (NiTi) shape memory alloy (SMA). As a mixture of oxygen and hydrogen gases makes contact with the platinum, the resulting exothermic reaction activates the nickel-titanium (NiTi)-based SMA. The MWCNT sheets serve as a support for the platinum particles and enhance the heat transfer due to the high thermal conductivity between the composite and the SMA. A hydrogen and oxygen fuel source could potentially provide higher power density than electrical sources. Several vehicle designs were considered and a peripheral SMA configuration under the robotic bell was chosen as the best arrangement. Constitutive equations combined with thermodynamic modeling were developed to understand the influence of system parameters that affect the overall actuation behavior of the fuel-powered SMA. The model is based on the changes in entropy of the hydrogen and oxygen fuel on the composite actuator within a channel. The specific heat capacity is the dominant factor controlling the width of the strain for various pulse widths of fuel delivery. Both theoretical and experimental strains for different diameter (100 and 150 µm) SMA/MWCNT/Pt fuel-powered muscles with dead weight attached at the end exhibited the highest magnitude under 450 ms of fuel delivery within 1.6 mm diameter conduit size. Fuel-powered bell deformation of 13.5% was found to be comparable to that of electrically powered (29%) and natural jellyfish (42%).

  1. Fuel saving device

    SciTech Connect

    Imbert, J. C.

    1984-01-10

    The present invention relates to a fuel saving device adaptable to all types of carburetors, petrol engines and domestic or industrial burners, constituted by a solenoid generating a magnetic field which has an influence on the air-fuel mixture. Said solenoid has a red copper coil, has its axis oriented in parallel to the axis of the engine, and, periodically, in a first pre-determined direction, during the moon phase which goes from the full moon to the new moon, and in a second, opposite, direction, during the moon phase going from the new moon to the full moon. The invention finds an application in motor engine of low consumption.

  2. Process for preparing a liquid fuel composition

    DOEpatents

    Singerman, Gary M.

    1982-03-16

    A process for preparing a liquid fuel composition which comprises liquefying coal, separating a mixture of phenols from said liquefied coal, converting said phenols to the corresponding mixture of anisoles, subjecting at least a portion of the remainder of said liquefied coal to hydrotreatment, subjecting at least a portion of said hydrotreated liquefied coal to reforming to obtain reformate and then combining at least a portion of said anisoles and at least a portion of said reformate to obtain said liquid fuel composition.

  3. MixtureTree annotator: a program for automatic colorization and visual annotation of MixtureTree.

    PubMed

    Chen, Shu-Chuan; Ogata, Aaron

    2015-01-01

    The MixtureTree Annotator, written in JAVA, allows the user to automatically color any phylogenetic tree in Newick format generated from any phylogeny reconstruction program and output the Nexus file. By providing the ability to automatically color the tree by sequence name, the MixtureTree Annotator provides a unique advantage over any other programs which perform a similar function. In addition, the MixtureTree Annotator is the only package that can efficiently annotate the output produced by MixtureTree with mutation information and coalescent time information. In order to visualize the resulting output file, a modified version of FigTree is used. Certain popular methods, which lack good built-in visualization tools, for example, MEGA, Mesquite, PHY-FI, TreeView, treeGraph and Geneious, may give results with human errors due to either manually adding colors to each node or with other limitations, for example only using color based on a number, such as branch length, or by taxonomy. In addition to allowing the user to automatically color any given Newick tree by sequence name, the MixtureTree Annotator is the only method that allows the user to automatically annotate the resulting tree created by the MixtureTree program. The MixtureTree Annotator is fast and easy-to-use, while still allowing the user full control over the coloring and annotating process. PMID:25826378

  4. MixtureTree annotator: a program for automatic colorization and visual annotation of MixtureTree.

    PubMed

    Chen, Shu-Chuan; Ogata, Aaron

    2015-01-01

    The MixtureTree Annotator, written in JAVA, allows the user to automatically color any phylogenetic tree in Newick format generated from any phylogeny reconstruction program and output the Nexus file. By providing the ability to automatically color the tree by sequence name, the MixtureTree Annotator provides a unique advantage over any other programs which perform a similar function. In addition, the MixtureTree Annotator is the only package that can efficiently annotate the output produced by MixtureTree with mutation information and coalescent time information. In order to visualize the resulting output file, a modified version of FigTree is used. Certain popular methods, which lack good built-in visualization tools, for example, MEGA, Mesquite, PHY-FI, TreeView, treeGraph and Geneious, may give results with human errors due to either manually adding colors to each node or with other limitations, for example only using color based on a number, such as branch length, or by taxonomy. In addition to allowing the user to automatically color any given Newick tree by sequence name, the MixtureTree Annotator is the only method that allows the user to automatically annotate the resulting tree created by the MixtureTree program. The MixtureTree Annotator is fast and easy-to-use, while still allowing the user full control over the coloring and annotating process.

  5. Thermodynamic study of (anthracene + phenanthrene) solid state mixtures

    PubMed Central

    Rice, James W.; Fu, Jinxia; Sandström, Emma; Ditto, Jenna C.; Suuberg, Eric M.

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAH) are common components of many materials, such as petroleum and various types of tars. They are generally present in mixtures, occurring both naturally and as byproducts of fuel processing operations. It is important to understand the thermodynamic properties of such mixtures in order to understand better and predict their behavior (i.e., fate and transport) in the environment and in industrial operations. To characterize better the thermodynamic behavior of PAH mixtures, the phase behavior of a binary (anthracene + phenanthrene) system was studied by differential scanning calorimetry, X-ray diffraction, and the Knudsen effusion technique. Mixtures of (anthracene + phenanthrene) exhibit non-ideal mixture behavior. They form a lower-melting, phenanthrene-rich phase with an initial melting temperature of 372 K (identical to the melting temperature of pure phenanthrene) and a vapor pressure of roughly lnP/Pa = −2.38. The phenanthrene-rich phase coexists with an anthracene-rich phase when the mole fraction of phenanthrene (xP) in the mixture is less than or equal to 0.80. Mixtures initially at xP = 0.90 consist entirely of the phenanthrene-rich phase and sublime at nearly constant vapor pressure and composition, consistent with azeotrope-like behavior. Quasi-azeotropy was also observed for very high-content anthracene mixtures (2.5 < xP < 5) indicating that anthracene may accommodate very low levels of phenanthrene in its crystal structure. PMID:26973354

  6. Kinetic Modeling of Gasoline Surrogate Components and Mixtures under Engine Conditions

    SciTech Connect

    Mehl, M; Pitz, W J; Westbrook, C K; Curran, H J

    2010-01-11

    Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, an improved version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multicomponent gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines (3-50 atm, 650-1200K, stoichiometric fuel/air mixtures). Simulation results are discussed focusing attention on the mixing effects of the fuel components.

  7. Single chamber fuel cells: Flow geometry, rate and composition considerations

    SciTech Connect

    Stefan, Ionel C.; Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

    2003-11-17

    Four different single chamber fuel cell designs were compared using propane-air gas mixtures. Gas flow around the electrodes has a significant influence on the open circuit voltage and the power density of the cell. The strong influence of flow geometry is likely due to its effect on gas composition, particularly on the oxygen chemical potential at the two electrodes as a result of gas mixing. The chamber design which exposes the cathode first to the inlet gas was found to yield the best performance at lower flow rates, while the open tube design with the electrodes equally exposed to the inlet gas worked best at higher flow rates.

  8. Effects of Fuel Distribution on Detonation Tube Performance

    NASA Technical Reports Server (NTRS)

    Perkins, H. Douglas; Sung, Chih-Jen

    2003-01-01

    A pulse detonation engine uses a series of high frequency intermittent detonation tubes to generate thrust. The process of filling the detonation tube with fuel and air for each cycle may yield non-uniform mixtures. Uniform mixing is commonly assumed when calculating detonation tube thrust performance. In this study, detonation cycles featuring idealized non-uniform Hz/air mixtures were analyzed using a two-dimensional Navier-Stokes computational fluid dynamics code with detailed chemistry. Mixture non-uniformities examined included axial equivalence ratio gradients, transverse equivalence ratio gradients, and partially fueled tubes. Three different average test section equivalence ratios were studied; one stoichiometric, one fuel lean, and one fuel rich. All mixtures were detonable throughout the detonation tube. Various mixtures representing the same average test section equivalence ratio were shown to have specific impulses within 1% of each other, indicating that good fuel/air mixing is not a prerequisite for optimal detonation tube performance under conditions investigated.

  9. California Natural Disasters - Using NASA Earth Observations to Assess Smoke Emissions, Fuel Loading, Moisture Content, and Vegetation Loss due to the 2009 Station Fire in the Angeles National Forest

    NASA Astrophysics Data System (ADS)

    Jones, M. L.; Reedy, J.; Moustafa, S.; Brundage, D.; Anderson, K.; Ferrare, R. A.; Swanson, A. J.; Yang, M. M.

    2010-12-01

    Wildfires are a normal occurrence in the state of California. Evidence of this can be seen in the Station Fire of 2009 (26 August - 16 October), a fire which destroyed over 154,000 acres of the Angeles National Forest and the combined summer fires of 2008 (22 May-29 August), which burned over 1,500,000 acres. In order to understand these fires it is important to consider several factors, including fire suppression, fuel loading, and the California climate. NDVI and NDMI maps for Angeles National forest were developed using Landsat 5 TM. The trend in live vegetation moisture content and vegetation condition for 2009 was found using these maps of Angeles National Forest. The NDMI maps were analyzed to understand changes in live vegetation moisture content that preceded the forest fires. Fuel for the Station fire was mapped using land classification through Landsat 5 TM and ASTER. This classification, along with moisture content levels, allowed for a method to map change in vegetation distribution, condition, and fuel load. The fuel load from these fires produces harmful emissions. These emissions contain large amounts of PM, including PM2.5, which are 2.5 micrometers in diameter and smaller (PM2.5). HYSPLIT trajectories were used to follow emissions from the 2008 summer fires to correlate with ARCTAS CARB data. HYSPLIT dispersion models were also used to show the deposition of particles in surrounding counties. Terra’s ASTER, MODIS, as well as data from EPA’s AirNow system, CARB AQMIS, and ARCTAS CARB flights were used to observe air quality factors such as PM2.5 levels, AOD, trace gases, and UV aerosol index. The results obtained from this study will demonstrate the feasibility of current and future NASA satellites to offer California policy makers assistance with more informed decision making.

  10. Alcohol fuels

    SciTech Connect

    Not Available

    1990-07-01

    Ethanol is an alcohol made from grain that can be blended with gasoline to extend petroleum supplies and to increase gasoline octane levels. Congressional proposals to encourage greater use of alternative fuels could increase the demand for ethanol. This report evaluates the growth potential of the ethanol industry to meet future demand increases and the impacts increased production would have on American agriculture and the federal budget. It is found that ethanol production could double or triple in the next eight years, and that American farmers could provide the corn for this production increase. While corn growers would benefit, other agricultural segments would not; soybean producers, for example could suffer for increased corn oil production (an ethanol byproduct) and cattle ranchers would be faced with higher feed costs because of higher corn prices. Poultry farmers might benefit from lower priced feed. Overall, net farm cash income should increase, and consumers would see slightly higher food prices. Federal budget impacts would include a reduction in federal farm program outlays by an annual average of between $930 million (for double current production of ethanol) to $1.421 billion (for triple production) during the eight-year growth period. However, due to an partial tax exemption for ethanol blended fuels, federal fuel tax revenues could decrease by between $442 million and $813 million.

  11. Degradation of jet fuel hydrocarbons by aquatic microbial communities. Interim report 23 October 1981-30 September 1983

    SciTech Connect

    Spain, J.C.; Somerville, C.C.; Butler, L.C.; Lee, T.J.; Bourquin, A.W.

    1983-11-01

    A model fuel mixture of fifteen hydrocarbons representative of those in distillate jet fuels was used to determine whether degradation by natural microbial communities could affect the persistence of such fuels released into aquatic environments. The mixture included hexane, cyclohexane, n-heptane, methylcyclohexane, toluene, n-octane, ethylcyclohexane, p-xylene, cumene, 1,3,5-trimethylbenzene, indan, naphthalene, 2-methylnaphthalene, n-tetradecane, and 2,3-dimethylnaphthalene. The water-soluble fraction of the model fuel was incubated in shake flasks with water or water and sediment suspensions collected at estuarine and freshwater sites. Surface films of the model mixture were studied under quiescent incubation. The disappearance of hydrocarbons was measured by capillary gas chromatography. Control flasks were sterilized with HgC1 to estimate losses due to abiotic processes. Fate tests were repeated with petroleum-derived JP-4. The soluble components of JP-4 were volatilized too rapidly for biodegradation to occur. Sedimentation dramatically affected the fate of fuel components when mixing of the hydrocarbon and sediment layers was studied. Sediment-associated components were more resistant to volatilization and microbial attack.

  12. Identifiability of large phylogenetic mixture models.

    PubMed

    Rhodes, John A; Sullivant, Seth

    2012-01-01

    Phylogenetic mixture models are statistical models of character evolution allowing for heterogeneity. Each of the classes in some unknown partition of the characters may evolve by different processes, or even along different trees. Such models are of increasing interest for data analysis, as they can capture the variety of evolutionary processes that may be occurring across long sequences of DNA or proteins. The fundamental question of whether parameters of such a model are identifiable is difficult to address, due to the complexity of the parameterization. Identifiability is, however, essential to their use for statistical inference.We analyze mixture models on large trees, with many mixture components, showing that both numerical and tree parameters are indeed identifiable in these models when all trees are the same. This provides a theoretical justification for some current empirical studies, and indicates that extensions to even more mixture components should be theoretically well behaved. We also extend our results to certain mixtures on different trees, using the same algebraic techniques.

  13. Soot formation during combustion of unsupported methanol/toluene mixture droplets in microgravity

    NASA Technical Reports Server (NTRS)

    Jackson, G. S.; Avedisian, C. T.; Yang, J. C.

    1991-01-01

    Results are reported of an experimental study tracing the influence of liquid composition on soot formation and the burning rate of a droplet composed of a binary miscible mixture of liquids. The mixture components represented a highly sooting fuel, toluene, and a nonsooting fuel, methanol. The toluene concentration in methanol was shown to dramatically influence flame luminosity and soot production. Neither burning rates nor a propensity for flame extinction appeared to be significantly affected by toluene mixture fractions. Five-percent toluene mixture droplets behaved like pure methanol droplets in terms of burning rate, lack of flame luminosity, and extinction. Increasing the toluene concentration in the droplets to 25 percent increased flame luminosity, yet no visible soot agglomerates were observed. The 50-percent-mixture droplets burned with highly luminous flames and large amounts of soot agglomerates collecting inside the flame. All the mixture droplets showed burning rates similar to those of pure methanol and likewise exhibited flame extinction before complete droplet vaporization.

  14. Pressure Effects in Droplet Combustion of Miscible Binary Fuels

    NASA Technical Reports Server (NTRS)

    Mikami, Masato; Habara, Osamu; Kono, Michikata; Sato, Jun-Ichi; Dietrich, Daniel L.; Williams, Forman A.

    1997-01-01

    The objective of this research is to improve understanding of the combustion of binary fuel mixtures in the vicinity of the critical point. Fiber-supported droplets of mixtures of n-heptane and n-hexadecane, initially 1 mm in diameter, were burned in room-temperature air at pressures from 1 MPa to 6 MPa under free-fall microgravity conditions. For most mixtures the total burning time was observed to achieve a minimum value at pressures well above the critical pressure of either of the pure fuels. This behavior is explained in terms of critical mixing conditions of a ternary system consisting of the two fuels and nitrogen. The importance of inert-gas dissolution in the liquid fuel near the critical point is thereby re-emphasized, and nonmonotonic dependence of dissolution on initial fuel composition is demonstrated. The results provide information that can be used to estimate high-pressure burning rates of fuel mixtures.

  15. Inerting Aircraft Fuel Systems Using Exhaust Gases

    NASA Technical Reports Server (NTRS)

    Hehemann, David G.

    2002-01-01

    Our purpose in this proposal was to determine the feasibility of using carbon dioxide, possibly obtained from aircraft exhaust gases as a substance to inert the fuel contained in fuel tanks aboard aircraft. To do this, we decided to look at the effects carbon dioxide has upon commercial Jet-A aircraft fuel. In particular, we looked at the solubility of CO2 in Jet-A fuel, the pumpability of CO2-saturated Jet-A fuel, the flashpoint of Jet-A fuel under various mixtures of air and CO2, the static outgassing of CO2-Saturated Jet-A fuel and the dynamic outgassing of Jet-A fuel during pumping of Jet-A fuel.

  16. Laser induced spark ignition of methane-oxygen mixtures

    NASA Technical Reports Server (NTRS)

    Santavicca, D. A.; Ho, C.; Reilly, B. J.; Lee, T.-W.

    1991-01-01

    Results from an experimental study of laser induced spark ignition of methane-oxygen mixtures are presented. The experiments were conducted at atmospheric pressure and 296 K under laminar pre-mixed and turbulent-incompletely mixed conditions. A pulsed, frequency doubled Nd:YAG laser was used as the ignition source. Laser sparks with energies of 10 mJ and 40 mJ were used, as well as a conventional electrode spark with an effective energy of 6 mJ. Measurements were made of the flame kernel radius as a function of time using pulsed laser shadowgraphy. The initial size of the spark ignited flame kernel was found to correlate reasonably well with breakdown energy as predicted by the Taylor spherical blast wave model. The subsequent growth rate of the flame kernel was found to increase with time from a value less than to a value greater than the adiabatic, unstretched laminar growth rate. This behavior was attributed to the combined effects of flame stretch and an apparent wrinkling of the flame surface due to the extremely rapid acceleration of the flame. The very large laminar flame speed of methane-oxygen mixtures appears to be the dominant factor affecting the growth rate of spark ignited flame kernels, with the mode of ignition having a small effect. The effect of incomplete fuel-oxidizer mixing was found to have a significant effect on the growth rate, one which was greater than could simply be accounted for by the effect of local variations in the equivalence ratio on the local flame speed.

  17. Fuel pin

    DOEpatents

    Christiansen, D.W.; Karnesky, R.A.; Leggett, R.D.; Baker, R.B.

    1987-11-24

    A fuel pin for a liquid metal nuclear reactor is provided. The fuel pin includes a generally cylindrical cladding member with metallic fuel material disposed therein. At least a portion of the fuel material extends radially outwardly to the inner diameter of the cladding member to promote efficient transfer of heat to the reactor coolant system. The fuel material defines at least one void space therein to facilitate swelling of the fuel material during fission.

  18. Evaluating Whole Chemical Mixtures and Sufficient Similarity

    EPA Science Inventory

    This powerpoint presentation supports apresentation describing dose-response assessment for complex chemical mixtures including deriving reference doses for mixtures evaluating sufficient similarity among chemical mixtures.

  19. Gaseous fueled torch apparatus and fueling module therefor

    SciTech Connect

    Czerwinski, K.S.; Gabany, E.; Sharma, S.S.; Turko, J.W.

    1990-06-05

    This patent describes a fueling system. It is used for supplying natural gas to one of a natural gas fueled torch apparatus and at least one storage vessel, the torch apparatus including a torch adapted for use in cutting or welding operations. The torch apparatus includes a source of oxygen for supplying oxygen to the torch, and the torch being selectively operable for combustion of a mixture of natural gas and oxygen. The fueling system is connectable to an electric power source and supplies natural gas to one of the torch apparatus and the storage vessel at an elevated pressure from a relatively low pressure natural gas supply system.

  20. A note on the meaning of mixture viscosity using the classical continuum theories of mixtures

    SciTech Connect

    Massoudi, Mehrdad

    2008-07-01

    In this paper we provide a brief review of the basic equations for the flow of two linearly viscous fluids using the mixture theory equations given in Atkin and Craine [R.J. Atkin, R.E. Craine, Continuum theories of mixtures: applications, J. Inst. Math. Appl. 17 (1976) 153; R.J. Atkin, R.E. Craine, Continuum theories of mixtures: basic theory and historical development, Quart. J. Mech. Appl. Math. 29 (1976) 290]. We then look at certain principles (or more accurately assumptions) due to Truesdell [C. Truesdell, Sulle basi della thermomeccanica, Rand Lincei, Series 8 22 (1957) 33–38, and 158–166] and Adkins [J.E. Adkins, Non-linear diffusion, 1. Diffusion and flow of mixtures of fluids, Philos. Trans. Roy. Soc. London A 255 (1963) 607–633; J.E. Adkins, Non-linear diffusion, 2. Constitutive equations for mixtures of isotropic fluids, Philos. Trans. Roy. Soc. London A 255 (1963) 635–648] and show that if the ‘assumption of the limiting cases’ of Adkins is to hold, then a very specific structure on the material properties of the two fluids has to be imposed. This new hypothesis provides one such condition for this requirement. An attempt is made to derive a relationship for the mixture viscosity using these ideas.

  1. Flame Propagation of Butanol Isomers/Air Mixtures

    SciTech Connect

    Veloo, Peter S.; Egolfopoulos, Fokion N.

    2011-01-01

    An experimental and computational study was conducted on the propagation of flames of saturated butanol isomers. The experiments were performed in the counterflow configuration under atmospheric pressure, unburned mixture temperature of 343 K, and for a wide range of equivalence ratios. The experiments were simulated using a recent kinetic model for the four isomers of butanol. Results indicate that n-butanol/air flames propagate somewhat faster than both sec-butanol/air and iso-butanol/air flames, and that tert-butanol/air flames propagate notably slower compared to the other three isomers. Reaction path analysis of tert-butanol/air flames revealed that iso-butene is a major intermediate, which subsequently reacts to form the resonantly stable iso-butenyl radical retarding thus the overall reactivity of tert-butanol/air flames relatively to the other three isomers. Through sensitivity analysis, it was determined that the mass burning rates of sec-butanol/air and iso-butanol/air flames are sensitive largely to hydrogen, carbon monoxide, and C{sub 1}–C{sub 2} hydrocarbon kinetics and not to fuel-specific reactions similarly to n-butanol/air flames. However, for tert-butanol/air flames notable sensitivity to fuel-specific reactions exists. While the numerical results predicted closely the experimental data for n-butanol/air and sec-butanol/air flames, they overpredicted and underpredicted the laminar flame speeds for iso-butanol/air and tert-butanol/air flames respectively. It was demonstrated further that the underprediction of the laminar flame speeds of tert-butanol/air flames by the model was most likely due to deficiencies of the C{sub 4}-alkene kinetics.

  2. Toxicological approaches to complex mixtures.

    PubMed Central

    Mauderly, J L

    1993-01-01

    This paper reviews the role of toxicological studies in understanding the health effects of environmental exposures to mixtures. The approach taken is to review mixtures that have received the greatest emphasis from toxicology; major mixtures research programs; the toxicologist's view of mixtures and approaches to their study; and the complementary roles of toxicological, clinical, and epidemiological studies. Studies of tobacco smoke, engine exhaust, combustion products, and air pollutants comprise most of the past research on mixtures. Because of their great experimental control over subjects, exposures, and endpoints, toxicologists tend to consider a wider range of toxic interactions among mixture components and sequential exposures than is practical for human studies. The three fundamental experimental approaches used by toxicologists are integrative (studying the mixture as a whole), dissective (dissecting a mixture to determine causative constituents), and synthetic (studying interactions between agents in simple combinations). Toxicology provides information on potential hazards, mechanisms by which mixture constituents interact to cause effects, and exposure dose-effect relationships; but extrapolation from laboratory data to quantitative human health risks is problematic. Toxicological, clinical, and epidemiological approaches are complementary but are seldom coordinated. Fostering synergistic interactions among the disciplines in studying the risks from mixtures could be advantageous. PMID:7515806

  3. Toxicological approaches to complex mixtures.

    PubMed

    Mauderly, J L

    1993-12-01

    This paper reviews the role of toxicological studies in understanding the health effects of environmental exposures to mixtures. The approach taken is to review mixtures that have received the greatest emphasis from toxicology; major mixtures research programs; the toxicologist's view of mixtures and approaches to their study; and the complementary roles of toxicological, clinical, and epidemiological studies. Studies of tobacco smoke, engine exhaust, combustion products, and air pollutants comprise most of the past research on mixtures. Because of their great experimental control over subjects, exposures, and endpoints, toxicologists tend to consider a wider range of toxic interactions among mixture components and sequential exposures than is practical for human studies. The three fundamental experimental approaches used by toxicologists are integrative (studying the mixture as a whole), dissective (dissecting a mixture to determine causative constituents), and synthetic (studying interactions between agents in simple combinations). Toxicology provides information on potential hazards, mechanisms by which mixture constituents interact to cause effects, and exposure dose-effect relationships; but extrapolation from laboratory data to quantitative human health risks is problematic. Toxicological, clinical, and epidemiological approaches are complementary but are seldom coordinated. Fostering synergistic interactions among the disciplines in studying the risks from mixtures could be advantageous.

  4. Gas and liquid fuel injection into an enclosed swirling flow

    NASA Astrophysics Data System (ADS)

    Ahmad, N. T.; Andrews, G. E.

    1984-06-01

    The use of swirler air for atomization has been tested with direct central propane injection and with direct central kerosene and gas oil injection, and its results have been compared with those for nonswirling flow systems under the same conditions. Direct propane injection results in a major extension of stability limits, by comparison to results for premixing, while with liquid fuel injection the stability limits are generally worse than for premixed fuel and air. This may be due to the action of the centrifugal forces on the liquid droplets in the swirl flow, which results in outer swirl flow vaporization and weaker mixtures in the core recirculation region than would be the case for propane injection. A comparison with nonswirling system performance indicated that all emission levels were higher with swirl for propane.

  5. Plasma enhancement of combustion of solid fuels

    SciTech Connect

    Askarova, A.S.; Karpenko, E.I.; Messerle, V.E.; Ustimenko, A.B.

    2006-03-15

    Plasma fuel systems that increase the coal burning efficiency are discussed. The systems were tested for fuel oil-free startup of boilers and stabilizating a pulverized-coal flame in power-generating boilers equipped with different types of burner and burning all types of power-generating coal. Plasma ignition, thermochemical treatment of an air-fuel mixture prior to combustion, and its burning in a power-generating boiler were numerically simulated. Environmental friendliness of the plasma technology was demonstrated.

  6. Comparative analysis of plant oil based fuels

    SciTech Connect

    Ziejewski, M.; Goettler, H.J.; Haines, H.; Huong, C.

    1995-12-31

    This paper presents the evaluation results from the analysis of different blends of fuels using the 13-mode standard SAE testing method. Six high oleic safflower oil blends, six ester blends, six high oleic sunflower oil blends, and six sunflower oil blends were used in this portion of the investigation. Additionally, the results from the repeated 13-mode tests for all the 25/75% mixtures with a complete diesel fuel test before and after each alternative fuel are presented.

  7. A jet fuel surrogate formulated by real fuel properties

    SciTech Connect

    Dooley, Stephen; Won, Sang Hee; Chaos, Marcos; Heyne, Joshua; Ju, Yiguang; Dryer, Frederick L.; Kumar, Kamal; Sung, Chih-Jen; Wang, Haowei; Oehlschlaeger, Matthew A.; Santoro, Robert J.; Litzinger, Thomas A.

    2010-12-15

    An implicit methodology based on chemical group theory to formulate a jet aviation fuel surrogate by the measurements of several combustion related fuel properties is tested. The empirical formula and derived cetane number of an actual aviation fuel, POSF 4658, have been determined. A three component surrogate fuel for POSF 4658 has been formulated by constraining a mixture of n-decane, iso-octane and toluene to reproduce the hydrogen/carbon ratio and derived cetane number of the target fuel. The validity of the proposed surrogate is evaluated by experimental measurement of select combustion properties of POSF 4658, and the POSF 4658 surrogate. (1)A variable pressure flow reactor has been used to chart the chemical reactivity of stoichiometric mixtures of POSF 4658/O{sub 2}/N{sub 2} and POSF 4658 surrogate/O{sub 2}/N{sub 2} at 12.5 atm and 500-1000 K, fixing the carbon content at 0.3% for both mixtures. (2)The high temperature chemical reactivity and chemical kinetic-molecular diffusion coupling of POSF 4658 and POSF 4658 surrogate have been evaluated by measurement of the strained extinction limit of diffusion flames. (3)The autoignition behavior of POSF 4658 and POSF 4658 surrogate has been measured with a shock tube at 674-1222 K and with a rapid compression machine at 645-714 K for stoichiometric mixtures of fuel in air at pressures close to 20 atm. The flow reactor study shows that the character and extent of chemical reactivity of both fuels at low temperature (500-675 K) and high temperature (900 K+) are extremely similar. Slight differences in the transition from the end of the negative temperature coefficient regime to hot ignition are observed. The diffusion flame strained extinction limits of the fuels are observed to be indistinguishable when compared on a molar basis. Ignition delay measurements also show that POSF 4658 exhibits NTC behavior. Moreover, the ignition delays of both fuels are also extremely similar over the temperature range studied in

  8. Agglomeration and defluidization in FBC of biomass fuels -- Mechanisms and measures for prevention

    SciTech Connect

    Nordin, A.; Oehman, M.; Skrifvars, B.J.; Hupa, M.

    1996-12-31

    The use of biomass fuels in fluidized bed combustion (FBC) and gasification (FBG) is becoming more important because of the environmental benefits associated with these fuel and processes. However, severe bed agglomeration and defluidization have been reported due to the special ash forming constituents of some biomass fuels. Previous results have indicated that this could possibly be prevented by intelligent fuel mixing. In the present work the mechanisms of bed agglomeration using two different biomass fuels as well as the mechanism of the prevention of agglomeration by co-combustion with coal (50/50 %{sub w}) were studied. Several repeated combustion tests with the two biomass fuels, alone (Lucerne and olive flesh), all resulted in agglomeration and defluidization of the bed within less than 30 minutes. By controlled defluidization experiments the initial cohesion temperatures for the two fuels were determined to be as low as 670 C and 940 C, respectively. However, by fuel mixing the initial agglomeration temperature increased to 950 C and more than 1050 C, respectively. When co-combusted with coal during ten hour extended runs, no agglomeration was observed for either of the two fuel mixtures. The agglomeration temperatures were compared with results from a laboratory method, based on compression strength measurements of ash pellets, and results from chemical equilibrium calculations. Samples of bed materials, collected throughout the experimental runs, as well as the produced agglomerated beds, were analyzed using SEM EDS and X-ray diffraction. The results showed that loss of fluidization resulted from formation of molten phases coating the bed materials; a salt melt in the case of Lucerne and a silicate melt in the case of the olive fuel. By fuel mixing, the in-bed ash composition is altered, conferring higher melting temperatures, and thereby agglomeration and defluidization can be prevented.

  9. 40 CFR 90.308 - Lubricating oil and test fuels.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... lubricants. (2) For 2-stroke engines, the fuel/oil mixture ratio must be that which is recommended by the..., manufacturers may use the fuel specified in 40 CFR part 1065, subpart H, for gasoline-fueled engines. (2...) Test fuels—service accumulation and aging. Unleaded gasoline representative of commercial...

  10. Sulfur tolerant molten carbonate fuel cell anode and process

    DOEpatents

    Remick, Robert J.

    1990-01-01

    Molten carbonate fuel cell anodes incorporating a sulfur tolerant carbon monoxide to hydrogen water-gas-shift catalyst provide in situ conversion of carbon monoxide to hydrogen for improved fuel cell operation using fuel gas mixtures of over about 10 volume percent carbon monoxide and up to about 10 ppm hydrogen sulfide.

  11. Antiandrogenic activity of phthalate mixtures: Validity of concentration addition

    SciTech Connect

    Christen, Verena; Crettaz, Pierre; Oberli-Schrämmli, Aurelia; Fent, Karl

    2012-03-01

    Phthalates and bisphenol A have very widespread use leading to significant exposure of humans. They are suspected to interfere with the endocrine system, including the androgen, estrogen and the thyroid hormone system. Here we analyzed the antiandrogenic activity of six binary, and one ternary mixture of phthalates exhibiting complete antiandrogenic dose–response curves, and binary mixtures of phthalates and bisphenol A at equi-effective concentrations of EC{sub 10}, EC{sub 25} and EC{sub 50} in MDA-kb2 cells. Mixture activity followed the concentration addition (CA) model with a tendency to synergism at high and antagonism at low concentrations. Isoboles and the toxic unit approach (TUA) confirmed the additive to synergistic activity of the binary mixtures BBP + DBP, DBP + DEP and DEP + BPA at high concentrations. Both methods indicate a tendency to antagonism for the EC{sub 10} mixtures BBP + DBP, BBP + DEP and DBP + DEP, and the EC{sub 25} mixture of DBP + BPA. A ternary mixture revealed synergism at the EC{sub 50}, and weak antagonistic activity at the EC{sub 25} level by the TUA. A mixture of five phthalates representing a human urine composition and reflecting exposure to corresponding parent compounds showed no antiandrogenic activity. Our study demonstrates that CA is an appropriate concept to account for mixture effects of antiandrogenic phthalates and bisphenol A. The interaction indicates a departure from additivity to antagonism at low concentrations, probably due to interaction with the androgen receptor and/or cofactors. This study emphasizes that a risk assessment of phthalates should account for mixture effects by applying the CA concept. -- Highlights: ► Antiandrogenic activity of mixtures of 2 and 3 phthalates are assessed in MDA-kb2 cells. ► Mixture activities followed the concentration addition model. ► A tendency to synergism at high and antagonism at low levels occurred.

  12. Sodium nitrate containing mixture for producing ceramic-glass-ceramic seal by microwave heating

    DOEpatents

    Blake, R.D.; Meek, T.T.

    1984-10-10

    A mixture for, and method of using such a mixture, for producing a ceramic-glass-ceramic seal by the use of microwave energy are disclosed, wherein the mixture comprises a glass sealing material, a coupling agent, and an oxidizer. The seal produced exhibits greater strength due to its different microstructure. Sodium nitrate is the most preferred oxidizer.

  13. Automotive Fuel Processor Development and Demonstration with Fuel Cell Systems

    SciTech Connect

    Nuvera Fuel Cells

    2005-04-15

    The potential for fuel cell systems to improve energy efficiency and reduce emissions over conventional power systems has generated significant interest in fuel cell technologies. While fuel cells are being investigated for use in many applications such as stationary power generation and small portable devices, transportation applications present some unique challenges for fuel cell technology. Due to their lower operating temperature and non-brittle materials, most transportation work is focusing on fuel cells using proton exchange membrane (PEM) technology. Since PEM fuel cells are fueled by hydrogen, major obstacles to their widespread use are the lack of an available hydrogen fueling infrastructure and hydrogen's relatively low energy storage density, which leads to a much lower driving range than conventional vehicles. One potential solution to the hydrogen infrastructure and storage density issues is to convert a conventional fuel such as gasoline into hydrogen onboard the vehicle using a fuel processor. Figure 2 shows that gasoline stores roughly 7 times more energy per volume than pressurized hydrogen gas at 700 bar and 4 times more than liquid hydrogen. If integrated properly, the fuel processor/fuel cell system would also be more efficient than traditional engines and would give a fuel economy benefit while hydrogen storage and distribution issues are being investigated. Widespread implementation of fuel processor/fuel cell systems requires improvements in several aspects of the technology, including size, startup time, transient response time, and cost. In addition, the ability to operate on a number of hydrocarbon fuels that are available through the existing infrastructure is a key enabler for commercializing these systems. In this program, Nuvera Fuel Cells collaborated with the Department of Energy (DOE) to develop efficient, low-emission, multi-fuel processors for transportation applications. Nuvera's focus was on (1) developing fuel processor

  14. Air tight fuel burning stove

    SciTech Connect

    Nietupski, V.J.

    1980-03-11

    A fuel burning stove is claimed for holding and burning fuel to heat the surrounding atmosphere in a room where the stove is employed. The stove includes a fire box which supports the fuel and where the combustion is sustained. An air inlet is provided to the fire box allowing the inflow of air for combustion with the fuel. The air is preheated upon entry into the fire box for mixture with volatiles formed by the burning fuel directed toward the entering air by a baffle means to effect a secondary combustion. In addition, a movable damper cooperates with the baffle to direct volatiles toward the incoming heated air when the damper is in the closed position and to provide a more direct path to the chimney when in the open position.

  15. Evaluating temperature and fuel stratification for heat-release rate control in a reactivity-controlled compression-ignition engine using optical diagnostics and chemical kinetics modeling

    SciTech Connect

    Musculus, Mark P. B.; Kokjohn, Sage L.; Reitz, Rolf D.

    2015-04-23

    We investigated the combustion process in a dual-fuel, reactivity-controlled compression-ignition (RCCI) engine using a combination of optical diagnostics and chemical kinetics modeling to explain the role of equivalence ratio, temperature, and fuel reactivity stratification for heat-release rate control. An optically accessible engine is operated in the RCCI combustion mode using gasoline primary reference fuels (PRF). A well-mixed charge of iso-octane (PRF = 100) is created by injecting fuel into the engine cylinder during the intake stroke using a gasoline-type direct injector. Later in the cycle, n-heptane (PRF = 0) is delivered through a centrally mounted diesel-type common-rail injector. This injection strategy generates stratification in equivalence ratio, fuel blend, and temperature. The first part of this study uses a high-speed camera to image the injection events and record high-temperature combustion chemiluminescence. Moreover, the chemiluminescence imaging showed that, at the operating condition studied in the present work, mixtures in the squish region ignite first, and the reaction zone proceeds inward toward the center of the combustion chamber. The second part of this study investigates the charge preparation of the RCCI strategy using planar laser-induced fluorescence (PLIF) of a fuel tracer under non-reacting conditions to quantify fuel concentration distributions prior to ignition. The fuel-tracer PLIF data show that the combustion event proceeds down gradients in the n-heptane distribution. The third part of the study uses chemical kinetics modeling over a range of mixtures spanning the distributions observed from the fuel-tracer fluorescence imaging to isolate the roles of temperature, equivalence ratio, and PRF number stratification. The simulations predict that PRF number stratification is the dominant factor controlling the ignition location and growth rate of the reaction zone. Equivalence ratio has a smaller, but still significant

  16. Gas emissions and engine behavior when gasoline-alcohol mixtures are used.

    PubMed

    Arapatsakos, C I; Karkanis, A N; Sparis, P D

    2003-09-01

    This paper deals with the use of gasoline-methanol and gasoline-ethanol mixtures in a small four-stroke engine of internal combustion that is used for the movement of a small alternative generator. It was observed that CO and HC emissions decrease compared to gasoline when the percentage of methanol, ethanol in the fuel was increased, under different load conditions (without load conditions and under full electrical load conditions). The use of gasoline-methanol mixtures showed a higher decrease of emissions. When the mixtures of gasoline-70%methanol and gasoline-90%ethanol and 100%ethanol for which the engine malfunctioned, the rpm of the engine were not constant and the emissions were increased. It is also important that (with the existing regulation of the fuel/air ratio that refers to gasoline) the engine functioned for the case of gasoline-methanol mixtures up to a concentration of -70%methanol mixture, while for the case of gasoline-ethanol mixtures until the use of 100%ethanol. Furthermore, during the use of the mixtures of gasoline-methanol and gasoline-ethanol there was a small increase of fuel consumption when the percentage of the methanol or ethanol in the fuel was increased.

  17. Combustion system for hybrid solar fossil fuel receiver

    DOEpatents

    Mehos, Mark S.; Anselmo, Kenneth M.; Moreno, James B.; Andraka, Charles E.; Rawlinson, K. Scott; Corey, John; Bohn, Mark S.

    2004-05-25

    A combustion system for a hybrid solar receiver comprises a pre-mixer which combines air and fuel to form an air-fuel mixture. The mixture is introduced tangentially into a cooling jacket. A burner plenum is fluidically connected to the cooling jacket such that the burner plenum and the cooling jacket are arranged in thermal contact with one another. The air-fuel mixture flows through the cooling jacket cooling the burner plenum to reduce pre-ignition of the air-fuel mixture in the burner plenum. A combustion chamber is operatively associated with and open to the burner plenum to receive the air-fuel mixture from the burner plenum. An igniter is operatively positioned in the combustion chamber to combust the air-fuel mixture, releasing heat. A recuperator is operatively associated with the burner plenum and the combustion chamber and pre-heats the air-fuel mixture in the burner plenum with heat from the combustion chamber. A heat-exchanger is operatively associated and in thermal contact with the combustion chamber. The heat-exchanger provides heat for the hybrid solar receiver.

  18. Detonation characteristics of dimethyl ether and ethanol-air mixtures

    NASA Astrophysics Data System (ADS)

    Diakow, P.; Cross, M.; Ciccarelli, G.

    2015-05-01

    The detonation cell structure in dimethyl ether vapor and ethanol vapor-air mixtures was measured at atmospheric pressure and initial temperatures in the range of 293-373 K. Tests were carried out in a 6.2-m-long, 10-cm inner diameter tube. For more reactive mixtures, a series of orifice plates were used to promote deflagration-to-detonation transition in the first half of the tube. For less reactive mixtures prompt detonation initiation was achieved with an acetylene-oxygen driver. The soot foil technique was used to capture the detonation cell structure. The measured cell size was compared to the calculated one-dimensional detonation reaction zone length. For fuel-rich dimethyl ether mixtures the calculated reaction zone is highlighted by a temperature gradient profile with two maxima, i.e., double heat release. The detonation cell structure was interpreted as having two characteristic sizes over the full range of mixture compositions. For mixtures at the detonation propagation limits the large cellular structure approached a single-head spin, and the smaller cells approached the size of the tube diameter. There is little evidence to support the idea that the two cell sizes observed on the foils are related to the double heat release predicted for the rich mixtures. There was very little influence of initial temperature on the cell size over the temperature range investigated. A double heat release zone was not predicted for ethanol-air detonations. The detonation cell size for stoichiometric ethanol-air was found to be similar to the size of the small cells for dimethyl ether. The measured cell size for ethanol-air did not vary much with composition in the range of 30-40 mm. For mixtures near stoichiometric it was difficult to discern multiple cell sizes. However, near the detonation limits there was strong evidence of a larger cell structure similar to that observed in dimethyl ether air mixtures.

  19. Using a low melting solvent mixture to extract value from wood biomass

    PubMed Central

    Hiltunen, Jaakko; Kuutti, Lauri; Rovio, Stella; Puhakka, Eini; Virtanen, Tommi; Ohra-Aho, Taina; Vuoti, Sauli

    2016-01-01

    Green chemistry, sustainability and eco-efficiency are guiding the development of the next generation of industrial chemical processes. The use of non-edible lignocellulosic biomass as a source of chemicals and fuels has recently raised interest due to the need for an alternative to fossil resources. Valorisation mainly focuses on cellulose, which has been used for various industrial scale applications for decades. However, creating an economically more viable value chain would require the exploitation of the other main components, hemicellulose and lignin. Here, we present a new low melting mixture composition based in boric acid and choline chloride, and demonstrate its efficiency in the fractionation of wood-based biomass for the production of non-condensed lignin, suitable for further use in the search for sustainable industrial applications, and for the selective conversion of hemicelluloses into valuable platform chemicals. PMID:27599741

  20. Using a low melting solvent mixture to extract value from wood biomass

    NASA Astrophysics Data System (ADS)

    Hiltunen, Jaakko; Kuutti, Lauri; Rovio, Stella; Puhakka, Eini; Virtanen, Tommi; Ohra-Aho, Taina; Vuoti, Sauli

    2016-09-01

    Green chemistry, sustainability and eco-efficiency are guiding the development of the next generation of industrial chemical processes. The use of non-edible lignocellulosic biomass as a source of chemicals and fuels has recently raised interest due to the need for an alternative to fossil resources. Valorisation mainly focuses on cellulose, which has been used for various industrial scale applications for decades. However, creating an economically more viable value chain would require the exploitation of the other main components, hemicellulose and lignin. Here, we present a new low melting mixture composition based in boric acid and choline chloride, and demonstrate its efficiency in the fractionation of wood-based biomass for the production of non-condensed lignin, suitable for further use in the search for sustainable industrial applications, and for the selective conversion of hemicelluloses into valuable platform chemicals.

  1. Using a low melting solvent mixture to extract value from wood biomass.

    PubMed

    Hiltunen, Jaakko; Kuutti, Lauri; Rovio, Stella; Puhakka, Eini; Virtanen, Tommi; Ohra-Aho, Taina; Vuoti, Sauli

    2016-01-01

    Green chemistry, sustainability and eco-efficiency are guiding the development of the next generation of industrial chemical processes. The use of non-edible lignocellulosic biomass as a source of chemicals and fuels has recently raised interest due to the need for an alternative to fossil resources. Valorisation mainly focuses on cellulose, which has been used for various industrial scale applications for decades. However, creating an economically more viable value chain would require the exploitation of the other main components, hemicellulose and lignin. Here, we present a new low melting mixture composition based in boric acid and choline chloride, and demonstrate its efficiency in the fractionation of wood-based biomass for the production of non-condensed lignin, suitable for further use in the search for sustainable industrial applications, and for the selective conversion of hemicelluloses into valuable platform chemicals. PMID:27599741

  2. Using a low melting solvent mixture to extract value from wood biomass.

    PubMed

    Hiltunen, Jaakko; Kuutti, Lauri; Rovio, Stella; Puhakka, Eini; Virtanen, Tommi; Ohra-Aho, Taina; Vuoti, Sauli

    2016-01-01

    Green chemistry, sustainability and eco-efficiency are guiding the development of the next generation of industrial chemical processes. The use of non-edible lignocellulosic biomass as a source of chemicals and fuels has recently raised interest due to the need for an alternative to fossil resources. Valorisation mainly focuses on cellulose, which has been used for various industrial scale applications for decades. However, creating an economically more viable value chain would require the exploitation of the other main components, hemicellulose and lignin. Here, we present a new low melting mixture composition based in boric acid and choline chloride, and demonstrate its efficiency in the fractionation of wood-based biomass for the production of non-condensed lignin, suitable for further use in the search for sustainable industrial applications, and for the selective conversion of hemicelluloses into valuable platform chemicals.

  3. LMFBR fuel assembly design for HCDA fuel dispersal

    DOEpatents

    Lacko, Robert E.; Tilbrook, Roger W.

    1984-01-01

    A fuel assembly for a liquid metal fast breeder reactor having an upper axial blanket region disposed in a plurality of zones within the fuel assembly. The characterization of a zone is dependent on the height of the axial blanket region with respect to the active fuel region. The net effect of having a plurality of zones is to establish a dispersal flow path for the molten materials resulting during a core meltdown accident. Upward flowing molten material can escape from the core region and/or fuel assembly without solidifying on the surface of fuel rods due to the heat sink represented by blanket region pellets.

  4. 46 CFR 119.455 - Fuel piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... boxes. All fuel lines and fittings must be accessible for inspection. (3) Shutoff valves, installed so... type opening on top for cleaning screens. Fuel filter and strainer bowls must be highly resistant to shattering due to mechanical impact and resistant to failure due to thermal shock. Fuel filters fitted...

  5. 46 CFR 119.455 - Fuel piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... boxes. All fuel lines and fittings must be accessible for inspection. (3) Shutoff valves, installed so... type opening on top for cleaning screens. Fuel filter and strainer bowls must be highly resistant to shattering due to mechanical impact and resistant to failure due to thermal shock. Fuel filters fitted...

  6. 46 CFR 119.455 - Fuel piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... boxes. All fuel lines and fittings must be accessible for inspection. (3) Shutoff valves, installed so... type opening on top for cleaning screens. Fuel filter and strainer bowls must be highly resistant to shattering due to mechanical impact and resistant to failure due to thermal shock. Fuel filters fitted...

  7. 46 CFR 119.455 - Fuel piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... boxes. All fuel lines and fittings must be accessible for inspection. (3) Shutoff valves, installed so... type opening on top for cleaning screens. Fuel filter and strainer bowls must be highly resistant to shattering due to mechanical impact and resistant to failure due to thermal shock. Fuel filters fitted...

  8. 46 CFR 119.455 - Fuel piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... boxes. All fuel lines and fittings must be accessible for inspection. (3) Shutoff valves, installed so... type opening on top for cleaning screens. Fuel filter and strainer bowls must be highly resistant to shattering due to mechanical impact and resistant to failure due to thermal shock. Fuel filters fitted...

  9. Mixture design and multivariate analysis in mixture research.

    PubMed Central

    Eide, I; Johnsen, H G

    1998-01-01

    Mixture design has been used to identify possible interactions between mutagens in a mixture. In this paper the use of mixture design in multidimensional isobolographic studies is introduced. Mutagenicity of individual nitro-polycyclic aromatic hydrocarbons (PAH) was evaluated is an organic extract of diesel exhaust particles (DEPs). The particles were extracted with dichloromethane (DCM). After replacing DCM with dimethyl sulfoxide, the extract was spiked with three individual nitro-PAH: 1-nitropyrene, 2-nitrofluorene, and 1,8-dinitropyrene. The nitro-PAH were added separately and in various combinations to the extract to determine the effects of each variable and to identify possible interactions between the individual nitro-PAH and between the nitro-PAH and the extract. The composition of the mixtures was determined by mixture design (linear axial normal) with four variables (the DEP extract and the three nitro-PAH, giving 8 different mixtures plus a triplicate centerpoint, i.e., a total of 11. The design supports a model with linear and interaction (product) terms. Two different approaches were used: traditional mixture design within a well-defined range on the linear part of the dose-response curves and an isobolographic mixture design with equipotent doses of each variable. The mixtures were tested for mutagenicity in the Ames assay using the TA98 strain of Salmonella typhimurium. The data were analyzed with projections to latent structures (PLS). The three individual nitro-PAH and the DEP extract acted additively in the Ames test. The use of mixture design either within a well-defined range of the linear part on the dose-response curve or with equipotent doses saves experiments and reduces the possibility of false interaction terms in situations with dose additivity or response additivity. Images Figure 1 Figure 2 PMID:9860895

  10. Mixture design and multivariate analysis in mixture research.

    PubMed

    Eide, I; Johnsen, H G

    1998-12-01

    Mixture design has been used to identify possible interactions between mutagens in a mixture. In this paper the use of mixture design in multidimensional isobolographic studies is introduced. Mutagenicity of individual nitro-polycyclic aromatic hydrocarbons (PAH) was evaluated is an organic extract of diesel exhaust particles (DEPs). The particles were extracted with dichloromethane (DCM). After replacing DCM with dimethyl sulfoxide, the extract was spiked with three individual nitro-PAH: 1-nitropyrene, 2-nitrofluorene, and 1,8-dinitropyrene. The nitro-PAH were added separately and in various combinations to the extract to determine the effects of each variable and to identify possible interactions between the individual nitro-PAH and between the nitro-PAH and the extract. The composition of the mixtures was determined by mixture design (linear axial normal) with four variables (the DEP extract and the three nitro-PAH, giving 8 different mixtures plus a triplicate centerpoint, i.e., a total of 11. The design supports a model with linear and interaction (product) terms. Two different approaches were used: traditional mixture design within a well-defined range on the linear part of the dose-response curves and an isobolographic mixture design with equipotent doses of each variable. The mixtures were tested for mutagenicity in the Ames assay using the TA98 strain of Salmonella typhimurium. The data were analyzed with projections to latent structures (PLS). The three individual nitro-PAH and the DEP extract acted additively in the Ames test. The use of mixture design either within a well-defined range of the linear part on the dose-response curve or with equipotent doses saves experiments and reduces the possibility of false interaction terms in situations with dose additivity or response additivity. PMID:9860895

  11. FUEL PROCESSING FOR FUEL CELLS: EFFECTS ON CATALYST DURABILITY AND CARBON FORMATION

    SciTech Connect

    R. BORUP; M. INBODY; B. MORTON; L. BROWN

    2001-05-01

    On-board production of hydrogen for fuel cells for automotive applications is a challenging developmental task. The fuel processor must show long term durability and under challenging conditions. Fuel processor catalysts in automotive fuel processors will be exposed to large thermal variations, vibrations, exposure to uncontrolled ambient conditions, and various impurities from ambient air and from fuel. For the commercialization of fuel processors, the delineation of effects on catalyst activity and durability are required. We are studying fuels and fuel constituent effects on the fuel processor system as part of the DOE Fuel Cells for Transportation program. Pure fuel components are tested to delineate the fuel component effect on the fuel processor and fuel processor catalysts. Component blends are used to simulate ''real fuels'', with various fuel mixtures being examined such as reformulated gasoline and naptha. The aliphatic, napthenic, olefin and aromatic content are simulated to represent the chemical kinetics of possible detrimental reactions, such as carbon formation, during fuel testing. Testing has examined the fuel processing performance of different fuel components to help elucidate the fuel constituent effects on fuel processing performance and upon catalyst durability. Testing has been conducted with vapor fuels, including natural gas and pure methane. The testing of pure methane and comparable testing with natural gas (97% methane) have shown some measurable differences in performance in the fuel processor. Major gasoline fuel constituents, such as aliphatic compounds, napthanes, and aromatics have been compared for their effect on the fuel processing performance. Experiments have been conducted using high-purity compounds to observe the fuel processing properties of the individual components and to document individual fuel component performance. The relative carbon formation of different fuel constituents have been measured by monitoring carbon via

  12. Familial searching on DNA mixtures with dropout.

    PubMed

    Slooten, K

    2016-05-01

    Familial searching, the act of searching a database for a relative of an unknown individual whose DNA profile has been obtained, is usually restricted to cases where the DNA profile of that person has been unambiguously determined. Therefore, it is normally applied only with a good quality single source profile as starting point. In this article we investigate the performance of the method if applied to mixtures with and without allelic dropout, when likelihood ratios are computed with a semi-continuous (binary) model. We show that mixtures with dropout do not necessarily perform worse than mixtures without, especially if some separation between the donors is possible due to their different dropout probabilities. The familial searching true and false positive rates of mixed profiles on 15 loci are in some cases better than those of single source profiles on 10 loci. Thus, the information loss due to the fact that the person of interest's DNA has been mixed with that of other, and is affected by dropout, can be less than the loss of information corresponding to having 5 fewer loci available for a single source trace. Profiles typed on 10 autosomal loci are often involved in familial searching casework since many databases, including the Dutch one, in part consist of such profiles. Therefore, from this point of view, there seems to be no objection to extend familial searching to mixed or degraded profiles.

  13. Thermophysical Properties of Hydrocarbon Mixtures

    National Institute of Standards and Technology Data Gateway

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

  14. COMPLEX MIXTURES AND GROUNDWATER QUALITY

    EPA Science Inventory

    Experience has shown that many soil and ground-water contamination problems involve complex mixtures of chemicals. his manuscript identifies and discusses, in a generic sense, some of the important processes which must be considered when dealing with complex mixtures in the subsu...

  15. A structural investigation of ionic liquid mixtures.

    PubMed

    Matthews, Richard P; Villar-Garcia, Ignacio J; Weber, Cameron C; Griffith, Jeraime; Cameron, Fiona; Hallett, Jason P; Hunt, Patricia A; Welton, Tom

    2016-03-28

    The structures of mixtures of ionic liquids (ILs) featuring a common 1-butyl-3-methylimidazolium ([C4C1im](+)) cation but different anions have been investigated both experimentally and computationally. (1)H and (13)C NMR of the ILs and their mixtures has been performed both on the undiluted liquids and those diluted by CD2Cl2. These experiments have been complemented by quantum chemical density functional theory calculations and molecular dynamics simulations. These techniques have identified the formation of preferential interactions between H(2) of the imidazolium cation and the most strongly hydrogen bond (H-bond) accepting anion. In addition, a preference for the more weakly H-bond accepting anion to interact above the imidazolium ring through anion-π(+) interactions has been identified. The modelling of these data has identified that the magnitude of these preferences are small, of the order of only a few kJ mol(-1), for all IL mixtures. No clustering of the anions around a specific cation could be observed, indicating that these interactions arise from the reorientation of the cation within a randomly assigned network of anions. π(+)-π(+) stacking of the imidazolium cations was also studied and found to be promoted by ILs with a strong H-bond accepting anion. Stacking interactions are easily disrupted by the introduction of small proportions (<50 mol%) of a weakly coordinating anion due to their propensity to form anion-π(+) interactions. These results suggest that the formation of IL mixtures with different anions leads to subtle structural changes of much lower energy than the Coulombic ordering of ions, accounting for why most IL mixtures exhibit ideal, or nearly ideal, behaviour. PMID:26947103

  16. A structural investigation of ionic liquid mixtures.

    PubMed

    Matthews, Richard P; Villar-Garcia, Ignacio J; Weber, Cameron C; Griffith, Jeraime; Cameron, Fiona; Hallett, Jason P; Hunt, Patricia A; Welton, Tom

    2016-03-28

    The structures of mixtures of ionic liquids (ILs) featuring a common 1-butyl-3-methylimidazolium ([C4C1im](+)) cation but different anions have been investigated both experimentally and computationally. (1)H and (13)C NMR of the ILs and their mixtures has been performed both on the undiluted liquids and those diluted by CD2Cl2. These experiments have been complemented by quantum chemical density functional theory calculations and molecular dynamics simulations. These techniques have identified the formation of preferential interactions between H(2) of the imidazolium cation and the most strongly hydrogen bond (H-bond) accepting anion. In addition, a preference for the more weakly H-bond accepting anion to interact above the imidazolium ring through anion-π(+) interactions has been identified. The modelling of these data has identified that the magnitude of these preferences are small, of the order of only a few kJ mol(-1), for all IL mixtures. No clustering of the anions around a specific cation could be observed, indicating that these interactions arise from the reorientation of the cation within a randomly assigned network of anions. π(+)-π(+) stacking of the imidazolium cations was also studied and found to be promoted by ILs with a strong H-bond accepting anion. Stacking interactions are easily disrupted by the introduction of small proportions (<50 mol%) of a weakly coordinating anion due to their propensity to form anion-π(+) interactions. These results suggest that the formation of IL mixtures with different anions leads to subtle structural changes of much lower energy than the Coulombic ordering of ions, accounting for why most IL mixtures exhibit ideal, or nearly ideal, behaviour.

  17. One-step catalytic conversion of biomass-derived carbohydrates to liquid fuels

    DOEpatents

    Sen, Ayusman; Yang, Weiran

    2014-03-18

    The invention relates to a method for manufacture of hydrocarbon fuels and oxygenated hydrocarbon fuels such as alkyl substituted tetrahydrofurans such as 2,5-dimethyltetrahydrofuran, 2-methyltetrahydrofuran, 5-methylfurfural and mixtures thereof. The method generally entails forming a mixture of reactants that includes carbonaceous material, water, a metal catalyst and an acid reacting that mixture in the presence of hydrogen. The reaction is performed at a temperature and for a time sufficient to produce a furan type hydrocarbon fuel. The process may be adapted to provide continuous manufacture of hydrocarbon fuels such as a furan type fuel.

  18. Air/fuel supply system for use in a gas turbine engine

    DOEpatents

    Fox, Timothy A; Schilp, Reinhard; Gambacorta, Domenico

    2014-06-17

    A fuel injector for use in a gas turbine engine combustor assembly. The fuel injector includes a main body and a fuel supply structure. The main body has an inlet end and an outlet end and defines a longitudinal axis extending between the outlet and inlet ends. The main body comprises a plurality of air/fuel passages extending therethrough, each air/fuel passage including an inlet that receives air from a source of air and an outlet. The fuel supply structure communicates with and supplies fuel to the air/fuel passages for providing an air/fuel mixture within each air/fuel passage. The air/fuel mixtures exit the main body through respective air/fuel passage outlets.

  19. State Relationships of Laminar Permanently-Blue Opposed-Jet Hydrocarbon-Fueled Diffusion Flames. Appendix D

    NASA Technical Reports Server (NTRS)

    Lin, K.-C.; Faeth, G. M.; Urban, D. L. (Technical Monitor)

    2000-01-01

    The structure and state relationships of laminar soot-free (permanently-blue) diffusion flames at various strain rates were studied experimentally using an opposed-jet configuration, motivated by the importance of soot-free hydrocarbon-fueled diffusion flames for many practical applications. Measurements of gas velocities, temperatures and compositions were carried out along the stagnation stream line. Flame conditions studied included propylene- and 1,3-butadiene-fueled opposed-jet diffusion flames having a stoichiometric mixture fractions of 0.7 and strain rates of 60-240 s (exp -1) at normal temperature and pressure. It was found that oxygen leakage to fuel-rich conditions and carbon monoxide leakage to fuel-lean conditions both increased as strain rates increased. Furthermore, increased strain rates caused increased fuel concentrations near the flame sheet, decreased peak gas temperatures, and decreased concentrations of carbon dioxide and water vapor throughout the flames. State relationships for major gas species and gas temperatures for these flames were found to exist over broad ranges of strain rates. In addition, current measurements, as well as previous measurements and predictions of ethylene-fueled permanently-blue diffusion flames, all having a stoichiometric mixture fraction of 0.7, were combined to establish generalized state relationships for permanently-blue diffusion flames for this stoichiometric mixture fraction. The combined measurements and predictions support relatively universal generalized state relationships for N2, CO2, H2O and fuel over a broad range of strain rates and fuel types. State relationships for O2 in the fuel-rich region, and for CO in the fuel-lean region, however, are functions of strain rate and fuel type. State relationships for H2 and temperature exhibit less universality, mainly due to the increased experimental uncertainties for these variables. The existence of state relationships for soot-free hydrocarbon-fueled

  20. Latent classiness and other mixtures.

    PubMed

    Neale, Michael C

    2014-05-01

    The aim of this article is to laud Lindon Eaves' role in the development of mixture modeling in genetic studies. The specification of models for mixture distributions was very much in its infancy when Professor Eaves implemented it in his own FORTRAN programs, and extended it to data collected from relatives such as twins. It was his collaboration with the author of this article which led to the first implementation of mixture distribution modeling in a general-purpose structural equation modeling program, Mx, resulting in a 1996 article on linkage analysis in Behavior Genetics. Today, the popularity of these methods continues to grow, encompassing methods for genetic association, latent class analysis, growth curve mixture modeling, factor mixture modeling, regime switching, marginal maximum likelihood, genotype by environment interaction, variance component twin modeling in the absence of zygosity information, and many others. This primarily historical article concludes with some consideration of some possible future developments. PMID:24477932

  1. Opportunity fuels

    SciTech Connect

    Lutwen, R.C.

    1996-12-31

    The paper consists of viewgraphs from a conference presentation. A comparison is made of opportunity fuels, defined as fuels that can be converted to other forms of energy at lower cost than standard fossil fuels. Types of fuels for which some limited technical data is provided include petroleum coke, garbage, wood waste, and tires. Power plant economics and pollution concerns are listed for each fuel, and compared to coal and natural gas power plant costs. A detailed cost breakdown for different plant types is provided for use in base fuel pricing.

  2. Evaluation of Codisposal Viability for TH/U Carbide (Fort Saint Vrain HTGR) DOE-Owned Fuel

    SciTech Connect

    H. radulescu

    2001-09-28

    There are more than 250 forms of US Department of Energy (DOE)-owned spent nuclear fuel (SNF). Due to the variety of the spent nuclear fuel, the National Spent Nuclear Fuel Program has designated nine representative fuel groups for disposal criticality analyses based on fuel matrix, primary fissile isotope, and enrichment. The Fort Saint Vrain reactor (FSVR) SNF has been designated as the representative fuel for the Th/U carbide fuel group. The FSVR SNF consists of small particles (spheres of the order of 0.5-mm diameter) of thorium carbide or thorium and high-enriched uranium carbide mixture, coated with multiple, thin layers of pyrolytic carbon and silicon carbide, which serve as miniature pressure vessels to contain fission products and the U/Th carbide matrix. The coated particles are bound in a carbonized matrix, which forms fuel rods or ''compacts'' that are loaded into large hexagonal graphite prisms. The graphite prisms (or blocks) are the physical forms that are handled in reactor loading and unloading operations, and which will be loaded into the DOE standardized SNF canisters. The results of the analyses performed will be used to develop waste acceptance criteria. The items that are important to criticality control are identified based on the analysis needs and result sensitivities. Prior to acceptance to fuel from the Th/U carbide fuel group for disposal, the important items for the fuel types that are being considered for disposal under the Th/U carbide fuel group must be demonstrated to satisfy the conditions determined in this report.

  3. Hydrogen-enriched fuels

    SciTech Connect

    Roser, R.

    1998-08-01

    NRG Technologies, Inc. is attempting to develop hardware and infrastructure that will allow mixtures of hydrogen and conventional fuels to become viable alternatives to conventional fuels alone. This commercialization can be successful if the authors are able to achieve exhaust emission levels of less than 0.03 g/kw-hr NOx and CO; and 0.15 g/kw-hr NMHC at full engine power without the use of exhaust catalysts. The major barriers to achieving these goals are that the lean burn regimes required to meet exhaust emissions goals reduce engine output substantially and tend to exhibit higher-than-normal total hydrocarbon emissions. Also, hydrogen addition to conventional fuels increases fuel cost, and reduces both vehicle range and engine output power. Maintaining low emissions during transient driving cycles has not been demonstrated. A three year test plan has been developed to perform the investigations into the issues described above. During this initial year of funding research has progressed in the following areas: (a) a cost effective single-cylinder research platform was constructed; (b) exhaust gas speciation was performed to characterize the nature of hydrocarbon emissions from hydrogen-enriched natural gas fuels; (c) three H{sub 2}/CH{sub 4} fuel compositions were analyzed using spark timing and equivalence ratio sweeping procedures and finally; (d) a full size pick-up truck platform was converted to run on HCNG fuels. The testing performed in year one of the three year plan represents a baseline from which to assess options for overcoming the stated barriers to success.

  4. Mixture Hidden Markov Models in Finance Research

    NASA Astrophysics Data System (ADS)

    Dias, José G.; Vermunt, Jeroen K.; Ramos, Sofia

    Finite mixture models have proven to be a powerful framework whenever unobserved heterogeneity cannot be ignored. We introduce in finance research the Mixture Hidden Markov Model (MHMM) that takes into account time and space heterogeneity simultaneously. This approach is flexible in the sense that it can deal with the specific features of financial time series data, such as asymmetry, kurtosis, and unobserved heterogeneity. This methodology is applied to model simultaneously 12 time series of Asian stock markets indexes. Because we selected a heterogeneous sample of countries including both developed and emerging countries, we expect that heterogeneity in market returns due to country idiosyncrasies will show up in the results. The best fitting model was the one with two clusters at country level with different dynamics between the two regimes.

  5. Analysis of gaseous fuel and air mixing in flames and flame quenching

    SciTech Connect

    Brasoveanu, D.

    1997-07-01

    A model for fuel-air mixing in flames is presented and applied to study the mixing and quenching of methane-air flames. The model is based on the ideal gas law, the energy equation, the equation of continuity and Arrhenius form of rate equation and is, therefore, strictly valid for mixtures having low density, i.e., for low pressure combustors. In the absence of preferential diffusion, chemical reactions cause an unbalanced consumption of fuel and oxygen in non-stoichiometric flames. Until the desired equivalence ratio is achieved, enhanced preferential diffusion of oxygen or fuel is required in fuel-rich or fuel-lean flames, respectively. After desired equivalence ratio is achieved, preferential diffusion of oxygen or fuel should be reduced to the exact level required to compensate the unbalanced consumption of fuel and air. In the absence of these conditions, flame chemistry cannot be strictly controlled. In addition, unless the desired equivalence ratio is at a position of stable equilibrium over an extended range of operational conditions, the flame may be quenched. Net transport of fuel or oxygen due to diffusion is correlated with distributions of pressure, temperature, velocity, species mass fractions and heat transfer through radiation and conduction. Results show that negative rates of pressure (or positive rates of temperature) and positive rates of pressure (or negative rates of temperature) can enhance preferential diffusion of oxygen and fuel, respectively. Negative velocity divergence also enhances diffusion of oxygen, while positive velocity divergence enhances diffusion of fuel. Recirculation of burnt gases improves the stability of all flames.

  6. Importance of Molecular Structure on the Thermophoresis of Binary Mixtures.

    PubMed

    Kumar, Pardeep; Goswami, Debabrata

    2014-12-26

    Using thermal lens spectroscopy, we study the role of molecular structural isomers of butanol on the thermophoresis (or Soret effect) of binary mixtures of methanol in butanol. In this study, we show that the thermal lens signal due to the Soret effect changes its sign for all the different concentrations of binary mixtures of butanol with methanol except for the one containing tertiary-butanol. The magnitude and sign of the Soret coefficients strongly depend on the molecular structure of the isomers of butanol in the binary mixture with methanol. This isomerization dependence is in stark contrast to the expected mass dependence of the Soret effect.

  7. Fuel electrode containing pre-sintered nickel/zirconia for a solid oxide fuel cell

    DOEpatents

    Ruka, Roswell J.; Vora, Shailesh D.

    2001-01-01

    A fuel cell structure (2) is provided, having a pre-sintered nickel-zirconia fuel electrode (6) and an air electrode (4), with a ceramic electrolyte (5) disposed between the electrodes, where the pre-sintered fuel electrode (6) contains particles selected from the group consisting of nickel oxide, cobalt and cerium dioxide particles and mixtures thereof, and titanium dioxide particles, within a matrix of yttria-stabilized zirconia and spaced-apart filamentary nickel strings having a chain structure, and where the fuel electrode can be sintered to provide an active solid oxide fuel cell.

  8. Catalytic combustion of heavy partially-vaporized fuels

    NASA Technical Reports Server (NTRS)

    Rosfjord, T. J.

    1980-01-01

    An experimental program to demonstrate efficient catalytic combustion of fuel-lean and fuel-rich mixtures of residual fuel and air, and to assess the influence of incomplete fuel vaporization on the performance of a catalytic reactor is being conducted. A 7.5-cm diameter catalytic reactor was designed and will be tested over a matrix of conditions representative of a gas turbine combustor inlet. For each of three test phases, two series of tests with a uniform but poorly vaporized (less than 50 percent) mixture of No. 6 fuel oil and air will be performed. In the first series, the non-vaporized fuel will be contained in a spray of droplets with a Sauter Mean Diameter (SMD) less than 30 microns. In the second series, the non-vaporized fuel will be characterized by a spray SMD approximately equal to 100 microns. The designs of the fuel injection system and the catalytic reactor are described in this paper.

  9. Fuel-Cell Water Separator

    NASA Technical Reports Server (NTRS)

    Burke, Kenneth Alan; Fisher, Caleb; Newman, Paul

    2010-01-01

    The main product of a typical fuel cell is water, and many fuel-cell configurations use the flow of excess gases (i.e., gases not consumed by the reaction) to drive the resultant water out of the cell. This two-phase mixture then exits through an exhaust port where the two fluids must again be separated to prevent the fuel cell from flooding and to facilitate the reutilization of both fluids. The Glenn Research Center (GRC) has designed, built, and tested an innovative fuel-cell water separator that not only removes liquid water from a fuel cell s exhaust ports, but does so with no moving parts or other power-consuming components. Instead it employs the potential and kinetic energies already present in the moving exhaust flow. In addition, the geometry of the separator is explicitly intended to be integrated into a fuel-cell stack, providing a direct mate with the fuel cell s existing flow ports. The separator is also fully scalable, allowing it to accommodate a wide range of water removal requirements. Multiple separators can simply be "stacked" in series or parallel to adapt to the water production/removal rate. GRC s separator accomplishes the task of water removal by coupling a high aspect- ratio flow chamber with a highly hydrophilic, polyethersulfone membrane. The hydrophilic membrane readily absorbs and transports the liquid water away from the mixture while simultaneously resisting gas penetration. The expansive flow path maximizes the interaction of the water particles with the membrane while minimizing the overall gas flow restriction. In essence, each fluid takes its corresponding path of least resistance, and the two fluids are effectively separated. The GRC fuel-cell water separator has a broad range of applications, including commercial hydrogen-air fuel cells currently being considered for power generation in automobiles.

  10. Production of liquid hydrocarbon and ether mixtures

    SciTech Connect

    Harandi, M.N.; Owen, H.

    1989-05-16

    An integrated process is described for the production of ether-rich liquid fuels, comprising: (a) etherifying a mixture of excess lower alkyl alcohol and aliphatic hydrocarbon feedstock rich in C/sub 4/+isoalkenes in the presence of acid etherification catalyst whereby lower alkyl tertiary alkyl ethers are produced; (b) separating etherification effluent from step(a) to provide a gasoline stream rich in C/sub 5/+ ethers and a stream comprising unreacted alcohol and alkenes; (c) contacting the unreacted alcohol and alkenes with an acidic metallosilicate zeolite conversion catalyst under olefinic and oxygenates conversion conditions at a temperature of at least 200/sup 0/C (392/sup 0/F) whereby a conversion effluent stream rich in C/sub 4/+ isoalkenes is produced; (d) recycling at least a portion of the conversion effluent stream to step (a) for etherification.

  11. Fuel cell development for transportation: Catalyst development

    SciTech Connect

    Doddapaneni, N.

    1996-04-01

    Fuel cells are being considered as alternate power sources for transportation and stationary applications. With proton exchange membrane (PEM) fuel cells the fuel crossover to cathodes causes severe thermal management and cell voltage drop due to oxidation of fuel at the platinized cathodes. The main goal of this project was to design, synthesize, and evaluate stable and inexpensive transition metal macrocyclic catalysts for the reduction of oxygen and be electrochemically inert towards anode fuels such as hydrogen and methanol.

  12. Characteristics of slush and boiling methane and methane mixtures.

    NASA Technical Reports Server (NTRS)

    Sindt, C. F.; Ludtke, P. R.

    1971-01-01

    Methane gas of two purities, 99.97% and 99%, was condensed to study the characteristics of the boiling liquid and the slush. In addition, binary mixtures of nitrogen and methane, and those of ethane and methane, and propane and methane, were also studied. Potential advantages of these gases when employed as fuels for high-performance aircraft, rocket engines, and motor vehicles are emphasized.

  13. Synthetic Fuel

    ScienceCinema

    Idaho National Laboratory - Steve Herring, Jim O'Brien, Carl Stoots

    2016-07-12

    Two global energy priorities today are finding environmentally friendly alternatives to fossil fuels, and reducing greenhouse gass Two global energy priorities today are finding environmentally friendly alternatives to fossil fuels, and reducing greenhous

  14. Fuel cells

    NASA Astrophysics Data System (ADS)

    1984-12-01

    The US Department of Energy (DOE), Office of Fossil Energy, has supported and managed a fuel cell research and development (R and D) program since 1976. Responsibility for implementing DOE's fuel cell program, which includes activities related to both fuel cells and fuel cell systems, has been assigned to the Morgantown Energy Technology Center (METC) in Morgantown, West Virginia. The total United States effort of the private and public sectors in developing fuel cell technology is referred to as the National Fuel Cell Program (NFCP). The goal of the NFCP is to develop fuel cell power plants for base-load and dispersed electric utility systems, industrial cogeneration, and on-site applications. To achieve this goal, the fuel cell developers, electric and gas utilities, research institutes, and Government agencies are working together. Four organized groups are coordinating the diversified activities of the NFCP. The status of the overall program is reviewed in detail.

  15. Synthetic Fuel

    SciTech Connect

    Idaho National Laboratory - Steve Herring, Jim O'Brien, Carl Stoots

    2008-03-26

    Two global energy priorities today are finding environmentally friendly alternatives to fossil fuels, and reducing greenhouse gass Two global energy priorities today are finding environmentally friendly alternatives to fossil fuels, and reducing greenhous

  16. Sterilization of fermentation vessels by ethanol/water mixtures

    DOEpatents

    Wyman, C.E.

    1999-02-09

    A method is described for sterilizing process fermentation vessels with a concentrated alcohol and water mixture integrated in a fuel alcohol or other alcohol production facility. Hot, concentrated alcohol is drawn from a distillation or other purification stage and sprayed into the empty fermentation vessels. This sterilizing alcohol/water mixture should be of a sufficient concentration, preferably higher than 12% alcohol by volume, to be toxic to undesirable microorganisms. Following sterilization, this sterilizing alcohol/water mixture can be recovered back into the same distillation or other purification stage from which it was withdrawn. The process of this invention has its best application in, but is not limited to, batch fermentation processes, wherein the fermentation vessels must be emptied, cleaned, and sterilized following completion of each batch fermentation process. 2 figs.

  17. Sterilization of fermentation vessels by ethanol/water mixtures

    DOEpatents

    Wyman, Charles E.

    1999-02-09

    A method for sterilizing process fermentation vessels with a concentrated alcohol and water mixture integrated in a fuel alcohol or other alcohol production facility. Hot, concentrated alcohol is drawn from a distillation or other purification stage and sprayed into the empty fermentation vessels. This sterilizing alcohol/water mixture should be of a sufficient concentration, preferably higher than 12% alcohol by volume, to be toxic to undesirable microorganisms. Following sterilization, this sterilizing alcohol/water mixture can be recovered back into the same distillation or other purification stage from which it was withdrawn. The process of this invention has its best application in, but is not limited to, batch fermentation processes, wherein the fermentation vessels must be emptied, cleaned, and sterilized following completion of each batch fermentation process.

  18. Sterilization of fermentation vessels by ethanol/water mixtures

    SciTech Connect

    Wyman, C.E.

    1991-03-20

    This invention is comprised of a method for sterilizing process fermentation vessels with a concentrated alcohol and water mixture integrated in a fuel alcohol or other alcohol production facility. Hot, concentrated alcohol is drawn from a distillation or other purification stage and sprayed into the empty fermentation vessels. This sterilizing alcohol/water mixture should be of a sufficient concentration, preferably higher than 12% alcohol by volume, to be toxic to undesirable microorganisms. Following sterilization, this sterilizing alcohol/water mixture can be recovered back into the same distillation or other purification stage from which it was withdrawn. The process of this invention has its best application in, but is not limited to, batch fermentation processes, wherein the fermentation vessels must be emptied, cleaned, and sterilized following completion of each batch fermentation process.

  19. Kinetics of plasma-assisted combustion: effect of non-equilibrium excitation on the ignition and oxidation of combustible mixtures

    NASA Astrophysics Data System (ADS)

    Popov, N. A.

    2016-08-01

    A review of experimental and theoretical investigations of the effect of atomic particles, and electronically and vibrationally excited molecules on the induction delay time and on the shift in the ignition temperature threshold of combustible mixtures is presented. The addition of oxygen and hydrogen atoms to combustible mixtures may cause a significant reduction in the ignition delay time. However, at relatively low initial temperatures, the non-equilibrium effect of the addition of atomic particles in ground electronic states is not pronounced. At the same time, the effect of excited O(1D) atoms on the oxidation and reforming of combustible mixtures is quite significant due to the high rates of reactions of O(1D) atoms with hydrogen and hydrocarbon molecules. In fuel–air mixtures, collisions with O(1D) atoms determine, under certain conditions, the dissociation of hydrocarbon molecules. Singlet oxygen molecules, O2(a1Δ g ), participate both in chain initiation and chain branching reactions, but the effect of O2(a1Δ g ) on the ignition processes is generally less important compared to oxygen atoms. The reactions of vibrationally excited molecules and the processes of VT-relaxation in combustible mixtures are discussed. The production of vibrationally excited N 2(v) molecules in fuel–air mixtures at relatively low electric field is very important. However, at the moment, the effect of the reactions of N 2(v) molecules on the oxidation and ignition of combustible mixtures is not completely clear, and requires further investigation. Therefore, with present knowledge, to reduce the ignition delay time and decrease the temperature threshold of combustive mixtures, the use of gas discharge systems with relatively high E/N values is recommended. In this case the reactions of electronically excited {{\\text{N}}2}≤ft(\\text{A}{}3Σu+,\\text{B}{}3{{\\Pi}g},\\text{C}{}3{{\\Pi}u},\\text{a}{}\\prime 1Σu-\\right) molecules, and atomic particles in ground and

  20. Fuel and soot oxidation in diesel-like conditions

    SciTech Connect

    Cavaliere, A.; Barbella, R.; Ciajolo, A.; D`Anna, A.; Ragucci, R.

    1994-12-31

    Diesel combustion has been studied under simplified experimental conditions in a nearly quiescent, high-temperature (900 K), high-pressure (4 MPa) environment by means of two-dimensional (2D) laser light scattering techniques and chemical analysis of gaseous and condensable material sampled by a fast-acting valve. Two model fuels, constituted of a simple alkane hydrocarbon (tetradecane (TD)) and an aromatic/aliphatic mixture ({alpha}-methylnaphthalene/tetradecane), have been used in order to study the effect of the fuel specificity on the combustion process. Temporal profiles of the scattering intensity and of the evolution of the oxidation progress evaluated by CO and CO{sub 2} determinations, have shown the same behavior independently on the fuel type and on the sampling location. For both fuels, the combustion proceeds through the formation of CO and subsequent oxidation to CO{sub 2}, which is anticipated with respect to the appearance of a scattering signal due to soot formation and is almost completed in correspondence of the beginning of soot oxidation. The early phase of the latter process takes place in correspondence of the CO depletion when OH radicals become available. The importance of this result consists in the recognition that mechanisms of soot oxidation by an OH attack can realistically occur in diesel engine combustion and that this is the only pathway through which soot oxidation takes place in characteristic timescales comparable to those of its formation.

  1. Carbonate fuel cell anodes

    DOEpatents

    Donado, R.A.; Hrdina, K.E.; Remick, R.J.

    1993-04-27

    A molten alkali metal carbonates fuel cell porous anode of lithium ferrite and a metal or metal alloy of nickel, cobalt, nickel/iron, cobalt/iron, nickel/iron/aluminum, cobalt/iron/aluminum and mixtures thereof wherein the total iron content including ferrite and iron of the composite is about 25 to about 80 percent, based upon the total anode, provided aluminum when present is less than about 5 weight percent of the anode. A process is described for production of the lithium ferrite containing anode by slipcasting.

  2. Carbonate fuel cell anodes

    DOEpatents

    Donado, Rafael A.; Hrdina, Kenneth E.; Remick, Robert J.

    1993-01-01

    A molten alkali metal carbonates fuel cell porous anode of lithium ferrite and a metal or metal alloy of nickel, cobalt, nickel/iron, cobalt/iron, nickel/iron/aluminum, cobalt/iron/aluminum and mixtures thereof wherein the total iron content including ferrite and iron of the composite is about 25 to about 80 percent, based upon the total anode, provided aluminum when present is less than about 5 weight percent of the anode. A process for production of the lithium ferrite containing anode by slipcasting.

  3. Prechamber initiation of detonation in gaseous mixtures

    NASA Astrophysics Data System (ADS)

    Bivol, G. Yu; Golovastov, S. V.; Golub, V. V.

    2015-11-01

    A process of deflagration-to-detonation transition in propane-butane-oxygen and acetylene-oxygen mixtures, in an open channel with a circular cross section with a diameter of 3 mm, was investigated experimentally. Detonation initiation was carried out by burning the mixture in the prechamber connected to the channel. The prechamber was considered as an extended source for the initiation of the detonation of a finite volume. To measure the velocity of a flame front, photodiodes, installed along the axis of the channel, were used. To determine the boundary conditions at the entrance to the channel, a piezoelectric pressure transducer was used. The influence of the dimensions of the prechamber, equivalence ratio and fuel on the pressure profile, and evolution of the flame front along the axis of the channel are presented. It was shown that, the dynamics of the flame front and shock waves in the channel can occur in different scenarios depending on the geometry of the prechamber and equivalence ratio. Two limit effects of the prechamber detonation initiation in the channel have been analyzed. The pre-detonation distances and the minimal energy of direct initiation of the detonation were determined.

  4. Chemical Kinetic Modeling of Advanced Transportation Fuels

    SciTech Connect

    PItz, W J; Westbrook, C K; Herbinet, O

    2009-01-20

    Development of detailed chemical kinetic models for advanced petroleum-based and nonpetroleum based fuels is a difficult challenge because of the hundreds to thousands of different components in these fuels and because some of these fuels contain components that have not been considered in the past. It is important to develop detailed chemical kinetic models for these fuels since the models can be put into engine simulation codes used for optimizing engine design for maximum efficiency and minimal pollutant emissions. For example, these chemistry-enabled engine codes can be used to optimize combustion chamber shape and fuel injection timing. They also allow insight into how the composition of advanced petroleum-based and non-petroleum based fuels affect engine performance characteristics. Additionally, chemical kinetic models can be used separately to interpret important in-cylinder experimental data and gain insight into advanced engine combustion processes such as HCCI and lean burn engines. The objectives are: (1) Develop detailed chemical kinetic reaction models for components of advanced petroleum-based and non-petroleum based fuels. These fuels models include components from vegetable-oil-derived biodiesel, oil-sand derived fuel, alcohol fuels and other advanced bio-based and alternative fuels. (2) Develop detailed chemical kinetic reaction models for mixtures of non-petroleum and petroleum-based components to represent real fuels and lead to efficient reduced combustion models needed for engine modeling codes. (3) Characterize the role of fuel composition on efficiency and pollutant emissions from practical automotive engines.

  5. Electrochemical fuel cell generator having an internal and leak tight hydrocarbon fuel reformer

    DOEpatents

    Dederer, Jeffrey T.; Hager, Charles A.

    1998-01-01

    An electrochemical fuel cell generator configuration is made having a generator section which contains a plurality of axially elongated fuel cells, each cell containing a fuel electrode, air electrode, and solid oxide electrolyte between the electrodes, in which axially elongated dividers separate portions of the fuel cells from each other, and where at least one divider also reforms a reformable fuel gas mixture prior to electricity generation reactions, the at least one reformer-divider is hollow having a closed end and an open end entrance for a reformable fuel mixture to pass to the closed end of the divider and then reverse flow and pass back along the hollowed walls to be reformed, and then finally to pass as reformed fuel out of the open end of the divider to contact the fuel cells, and further where the reformer-divider is a composite structure having a gas diffusion barrier of metallic foil surrounding the external walls of the reformer-divider except at the entrance to prevent diffusion of the reformable gas mixture through the divider, and further housed in an outer insulating jacket except at the entrance to prevent short-circuiting of the fuel cells by the gas diffusion barrier.

  6. Electrochemical fuel cell generator having an internal and leak tight hydrocarbon fuel reformer

    DOEpatents

    Dederer, J.T.; Hager, C.A.

    1998-03-31

    An electrochemical fuel cell generator configuration is made having a generator section which contains a plurality of axially elongated fuel cells, each cell containing a fuel electrode, air electrode, and solid oxide electrolyte between the electrodes, in which axially elongated dividers separate portions of the fuel cells from each other, and where at least one divider also reforms a reformable fuel gas mixture prior to electricity generation reactions, the at least one reformer-divider is hollow having a closed end and an open end entrance for a reformable fuel mixture to pass to the closed end of the divider and then reverse flow and pass back along the hollowed walls to be reformed, and then finally to pass as reformed fuel out of the open end of the divider to contact the fuel cells, and further where the reformer-divider is a composite structure having a gas diffusion barrier of metallic foil surrounding the external walls of the reformer-divider except at the entrance to prevent diffusion of the reformable gas mixture through the divider, and further housed in an outer insulating jacket except at the entrance to prevent short-circuiting of the fuel cells by the gas diffusion barrier. 10 figs.

  7. Fossil Fuels.

    ERIC Educational Resources Information Center

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with fossil fuels. Some topics covered are historic facts, development of fuels, history of oil production, current and future trends of the oil industry, refining fossil fuels, and environmental problems. Material in each unit may…

  8. Proteomics based compositional analysis of complex cellulase-hemicellulase mixtures

    SciTech Connect

    Chundawat, Shishir P.; Lipton, Mary S.; Purvine, Samuel O.; Uppugundla, Nirmal; Gao, Dahai; Balan, Venkatesh; Dale, Bruce E.

    2011-10-07

    Efficient deconstruction of cellulosic biomass to fermentable sugars for fuel and chemical production is accomplished by a complex mixture of cellulases, hemicellulases and accessory enzymes (e.g., >50 extracellular proteins). Cellulolytic enzyme mixtures, produced industrially mostly using fungi like Trichoderma reesei, are poorly characterized in terms of their protein composition and its correlation to hydrolytic activity on cellulosic biomass. The secretomes of commercial glycosyl hydrolase producing microbes was explored using a proteomics approach with high-throughput quantification using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Here, we show that proteomics based spectral counting approach is a reasonably accurate and rapid analytical technique that can be used to determine protein composition of complex glycosyl hydrolase mixtures that also correlates with the specific activity of individual enzymes present within the mixture. For example, a strong linear correlation was seen between Avicelase activity and total cellobiohydrolase content. Reliable, quantitative and cheaper analytical methods that provide insight into the cellulosic biomass degrading fungal and bacterial secretomes would lead to further improvements towards commercialization of plant biomass derived fuels and chemicals.

  9. Reaction products of amido-amine and epoxide useful as fuel additives

    SciTech Connect

    Efner, H.F.

    1988-04-12

    A method for reducing engine deposits in an internal combustion engine is described comprising the addition of a detergent fuel additive package to a hydrocarbon fuel for the engine. The fuel detergent is added in an amount effective to reduce deposits and the hydrocarbon fuel is used with detergent additive as fuel in an internal combustion engine. The detergent fuel additive package comprises: (1) a fuel detergent additive that is the reaction product prepared by reacting (a) vegetable oil or (b) higher carboxylic acid chosen from (i) aliphatic fatty acids having 10-25 carbon atoms and (ii) aralkyl acids having 12-42 carbon atoms with (c) multiamine to obtain a fist product mixture with the first product mixture reacted with alklylene oxide to produce a second product mixture and (2) a fuel detergent additive solvent compatible with the fuels.

  10. Patch testing with perfume mixture.

    PubMed

    Veien, N K; Hattel, T; Justesen, O; Nørholm, A

    1982-01-01

    145 of 1116 patients patch tested with the standard series of the International Contact Dermatitis Research Group, including the recently introduced perfume mixture, had positive patch test reactions to at least one of the traditional screening agents for fragrance allergy or to the perfume mixture. In 96 of 145 patients the positive patch tests could be explained as being related to fragrance allergy. The perfume mixture was considered a useful screening agent for fragrance allergy. However, the results indicate that it is still necessary to employ several screening agents to detect this type of hypersensitivity.

  11. Catalytic combustion with incompletely vaporized residual fuel

    NASA Technical Reports Server (NTRS)

    Rosfjord, T. J.

    1981-01-01

    Catalytic combustion of fuel lean mixtures of incompletely vaporized residual fuel and air was investigated. The 7.6 cm diameter, graded cell reactor was constructed from zirconia spinel substrate and catalyzed with a noble metal catalyst. Streams of luminous particles exited the rector as a result of fuel deposition and carbonization on the substrate. Similar results were obtained with blends of No. 6 and No. 2 oil. Blends of shale residual oil and No. 2 oil resulted in stable operation. In shale oil blends the combustor performance degraded with a reduced degree of fuel vaporization. In tests performed with No. 2 oil a similar effect was observed.

  12. Fuel-air control device

    SciTech Connect

    Norman, J.

    1981-12-15

    The invention concerns a device for controlling the vehicles fuel-air mixture by regulating the air in the ventilation passage leading to the engine air intake from the crankcase. In a vehicle provided with a PCV valve, the device is located in the ventilation passage leading from the crankcase to the engine air intake and the device is downstream of the PCV valve. The device admits outside air to the ventilation passage to lean the gas mixture when the engine creates a vacuum less than 8 psi in the ventilation passage.

  13. Chitosan biopolymer for fuel cell applications.

    PubMed

    Ma, Jia; Sahai, Yogeshwar

    2013-02-15

    Fuel cell is an electrochemical device which converts chemical energy stored in a fuel into electrical energy. Fuel cells have been receiving attention due to its potential applicability as a good alternative power source. Recently, cost-effective and eco-friendly biopolymer chitosan has been extensively studied as a material for membrane electrolytes and electrodes in low to intermediate temperature hydrogen polymer electrolyte fuel cell, direct methanol fuel cell, alkaline fuel cell, and biofuel cell. This paper reviews structure and property of chitosan with respect to its applications in fuel cells. Recent achievements and prospect of its applications have also been included.

  14. Effect of Inhomogeneous Mixture Properties on CI Combustion in a Schnurle-Type Gasoline DI Engine

    NASA Astrophysics Data System (ADS)

    Kim, Seok-Woo; Moriyoshi, Yasuo

    The authors have performed experiments on compression-ignition (CI) for a single-cylinder Schnurle-type two-stroke gasoline direct injection (DI) engine which employs a variable exhaust port, area, and deduced two presumptions from the experimental results. Firstly, the spatial distributions of fuel concentration and in-cylinder gas temperature are indispensable to enable CI operation under stratified charge conditions, because CI operation is not possible in a DI system although the necessary conditions of the scavenging efficiency and the in-cylinder gas temperature for the initiation of CI in homogeneous charge conditions are satisfied. Secondly, it is possible that flame propagation occurs in stratified charge CI conditions, because the combustion period in the later stage after 80% mass burned becomes longer than that with homogeneous charge CI combustion. In this report, in order to verify the above two presumptions deduced from experiments, the gas exchange process and mixture formation process were numerically analyzed, and the initiation conditions of CI were estimated using a CHEMKIN application. As a result, in case of CI with a late injection timing in DI system, it was found that CI was possible because high temperature but no fuel region and low temperature but rich fuel region exist in the cylinder due to inhomogeneous spatial distributions of fuel and temperature. Also, in case of CI with a late injection timing, the flame propagation was possible in the low-temperature and diluted rich region. Thereby, the two presumptions deduced from the experimental results were validated from the numerical analysis results.

  15. Flame ignition studies of conventional and alternative jet fuels and surrogate components

    NASA Astrophysics Data System (ADS)

    Liu, Ning

    Practical jet fuels are widely used in air-breathing propulsion, but the chemical mechanisms that control their combustion are not yet understood. Thousands of components are contained in conventional and alternative jet fuels, making thus any effort to model their combustion behavior a daunting task. That has been the motivation behind the development of surrogate fuels that contain typically a small number of neat components, whose physical properties and combustion behavior mimic those of the real jet fuel, and whose kinetics could be modeled with increased degree of confidence. Towards that end, a large number of experimental data are required both for the real fuels and the attendant surrogate components that could be used to develop and validate detailed kinetic models. Those kinetic models could be used then upon reduction to model a combustor and eventually optimize its performance. Among all flame phenomena, ignition is rather sensitive to the oxidative and pyrolytic propensity of the fuel as well as to its diffusivity. The counterflow configuration is ideal in probing both the fuel reactivity and diffusivity aspects of the ignition process and it was used in the present work to determine the ignition temperatures of premixed and non-premixed flames of a variety of fuels relevant to air-breathing propulsion. The experiments were performed at atmospheric pressure, elevated unburned fuel mixture temperatures, and various strain rates that were measured locally. Several recent kinetic models were used in direct numerical simulations of the experiments and the computed results were tested against the experimental data. Furthermore, through sensitivity, reaction path, and structure analyses of the computed flames, insight was provided into the dominant mechanisms that control ignition. It was found that ignition is primarily sensitive to fuel diffusion and secondarily sensitive to chemical kinetics and intermediate species diffusivities under the low fuel

  16. Novel design for transparent high-pressure fuel injector nozzles.

    PubMed

    Falgout, Z; Linne, M

    2016-08-01

    The efficiency and emissions of internal combustion (IC) engines are closely tied to the formation of the combustible air-fuel mixture. Direct-injection engines have become more common due to their increased practical flexibility and efficiency, and sprays dominate mixture formation in these engines. Spray formation, or rather the transition from a cylindrical liquid jet to a field of isolated droplets, is not completely understood. However, it is known that nozzle orifice flow and cavitation have an important effect on the formation of fuel injector sprays, even if the exact details of this effect remain unknown. A number of studies in recent years have used injectors with optically transparent nozzles (OTN) to allow observation of the nozzle orifice flow. Our goal in this work is to design various OTN concepts that mimic the flow inside commercial injector nozzles, at realistic fuel pressures, and yet still allow access to the very near nozzle region of the spray so that interior flow structure can be correlated with primary breakup dynamics. This goal has not been achieved until now because interior structures can be very complex, and the most appropriate optical materials are brittle and easily fractured by realistic fuel pressures. An OTN design that achieves realistic injection pressures and grants visual access to the interior flow and spray formation will be explained in detail. The design uses an acrylic nozzle, which is ideal for imaging the interior flow. This nozzle is supported from the outside with sapphire clamps, which reduces tensile stresses in the nozzle and increases the nozzle's injection pressure capacity. An ensemble of nozzles were mechanically tested to prove this design concept. PMID:27587161

  17. Novel design for transparent high-pressure fuel injector nozzles.

    PubMed

    Falgout, Z; Linne, M

    2016-08-01

    The efficiency and emissions of internal combustion (IC) engines are closely tied to the formation of the combustible air-fuel mixture. Direct-injection engines have become more common due to their increased practical flexibility and efficiency, and sprays dominate mixture formation in these engines. Spray formation, or rather the transition from a cylindrical liquid jet to a field of isolated droplets, is not completely understood. However, it is known that nozzle orifice flow and cavitation have an important effect on the formation of fuel injector sprays, even if the exact details of this effect remain unknown. A number of studies in recent years have used injectors with optically transparent nozzles (OTN) to allow observation of the nozzle orifice flow. Our goal in this work is to design various OTN concepts that mimic the flow inside commercial injector nozzles, at realistic fuel pressures, and yet still allow access to the very near nozzle region of the spray so that interior flow structure can be correlated with primary breakup dynamics. This goal has not been achieved until now because interior structures can be very complex, and the most appropriate optical materials are brittle and easily fractured by realistic fuel pressures. An OTN design that achieves realistic injection pressures and grants visual access to the interior flow and spray formation will be explained in detail. The design uses an acrylic nozzle, which is ideal for imaging the interior flow. This nozzle is supported from the outside with sapphire clamps, which reduces tensile stresses in the nozzle and increases the nozzle's injection pressure capacity. An ensemble of nozzles were mechanically tested to prove this design concept.

  18. Novel design for transparent high-pressure fuel injector nozzles

    NASA Astrophysics Data System (ADS)

    Falgout, Z.; Linne, M.

    2016-08-01

    The efficiency and emissions of internal combustion (IC) engines are closely tied to the formation of the combustible air-fuel mixture. Direct-injection engines have become more common due to their increased practical flexibility and efficiency, and sprays dominate mixture formation in these engines. Spray formation, or rather the transition from a cylindrical liquid jet to a field of isolated droplets, is not completely understood. However, it is known that nozzle orifice flow and cavitation have an important effect on the formation of fuel injector sprays, even if the exact details of this effect remain unknown. A number of studies in recent years have used injectors with optically transparent nozzles (OTN) to allow observation of the nozzle orifice flow. Our goal in this work is to design various OTN concepts that mimic the flow inside commercial injector nozzles, at realistic fuel pressures, and yet still allow access to the very near nozzle region of the spray so that interior flow structure can be correlated with primary breakup dynamics. This goal has not been achieved until now because interior structures can be very complex, and the most appropriate optical materials are brittle and easily fractured by realistic fuel pressures. An OTN design that achieves realistic injection pressures and grants visual access to the interior flow and spray formation will be explained in detail. The design uses an acrylic nozzle, which is ideal for imaging the interior flow. This nozzle is supported from the outside with sapphire clamps, which reduces tensile stresses in the nozzle and increases the nozzle's injection pressure capacity. An ensemble of nozzles were mechanically tested to prove this design concept.

  19. Antiandrogenic activity of phthalate mixtures: validity of concentration addition.

    PubMed

    Christen, Verena; Crettaz, Pierre; Oberli-Schrämmli, Aurelia; Fent, Karl

    2012-03-01

    Phthalates and bisphenol A have very widespread use leading to significant exposure of humans. They are suspected to interfere with the endocrine system, including the androgen, estrogen and the thyroid hormone system. Here we analyzed the antiandrogenic activity of six binary, and one ternary mixture of phthalates exhibiting complete antiandrogenic dose-response curves, and binary mixtures of phthalates and bisphenol A at equi-effective concentrations of EC(10), EC(25) and EC(50) in MDA-kb2 cells. Mixture activity followed the concentration addition (CA) model with a tendency to synergism at high and antagonism at low concentrations. Isoboles and the toxic unit approach (TUA) confirmed the additive to synergistic activity of the binary mixtures BBP+DBP, DBP+DEP and DEP+BPA at high concentrations. Both methods indicate a tendency to antagonism for the EC(10) mixtures BBP+DBP, BBP+DEP and DBP+DEP, and the EC(25) mixture of DBP+BPA. A ternary mixture revealed synergism at the EC(50), and weak antagonistic activity at the EC(25) level by the TUA. A mixture of five phthalates representing a human urine composition and reflecting exposure to corresponding parent compounds showed no antiandrogenic activity. Our study demonstrates that CA is an appropriate concept to account for mixture effects of antiandrogenic phthalates and bisphenol A. The interaction indicates a departure from additivity to antagonism at low concentrations, probably due to interaction with the androgen receptor and/or cofactors. This study emphasizes that a risk assessment of phthalates should account for mixture effects by applying the CA concept.

  20. Alternative fuels

    NASA Technical Reports Server (NTRS)

    Grobman, J. S.; Butze, H. F.; Friedman, R.; Antoine, A. C.; Reynolds, T. W.

    1977-01-01

    Potential problems related to the use of alternative aviation turbine fuels are discussed and both ongoing and required research into these fuels is described. This discussion is limited to aviation turbine fuels composed of liquid hydrocarbons. The advantages and disadvantages of the various solutions to the problems are summarized. The first solution is to continue to develop the necessary technology at the refinery to produce specification jet fuels regardless of the crude source. The second solution is to minimize energy consumption at the refinery and keep fuel costs down by relaxing specifications.

  1. Improved electrolytes for fuel cells

    SciTech Connect

    Gard, G.L.; Roe, D.K.

    1991-06-01

    Present day fuel cells based upon hydrogen and oxygen have limited performance due to the use of phosphoric acid as an electrolyte. Improved performance is desirable in electrolyte conductivity, electrolyte management, oxygen solubility, and the kinetics of the reduction of oxygen. Attention has turned to fluorosulfonic acids as additives or substitute electrolytes to improve fuel cell performance. The purpose of this project is to synthesize and electrochemically evaluate new fluorosulfonic acids as superior alternatives to phosphoric acid in fuel cells. (VC)

  2. Prospective studies of HTR fuel cycles involving plutonium

    SciTech Connect

    Bonin, B.; Greneche, D.; Carre, F.; Damian, F.; Doriath, J.Y.

    2002-07-01

    High Temperature Gas Cooled reactors (HTRs) are able to accommodate a wide variety of mixtures of fissile and fertile materials without any significant modification of the core design. This flexibility is due to an uncoupling between the parameters of cooling geometry, and the parameters which characterize neutronic optimisation (moderation ratio or heavy nuclide concentration and distribution). Among other advantageous features, an HTR core has a better neutron economy than a LWR because there is much less parasitic capture in the moderator (capture cross section of graphite is 100 times less than the one of water) and in internal structures. Moreover, thanks to the high resistance of the coated particles, HTR fuels are able to reach very high burn-ups, far beyond the possibilities offered by other fuels (except the special case of molten salt reactors). These features make HTRs especially interesting for closing the nuclear fuel cycle and stabilizing the plutonium inventory. A large number of fuel cycle studies are already available today, on 3 main categories of fuel cycles involving HTRs: i) High enriched uranium cycle, based on thorium utilization as a fertile material and HEU as a fissile material; ii) Low enriched uranium cycle, where only LEU is used (from 5% to 12%); iii) Plutonium cycle based on the utilization of plutonium only as a fissile material, with (or without) fertile materials. Plutonium consumption at high burnups in HTRs has already been tested with encouraging results under the DRAGON project and at Peach Bottom. To maximize plutonium consumption, recent core studies have also been performed on plutonium HTR cores, with special emphasis on weapon-grade plutonium consumption. In the following, we complete the picture by a core study for a HTR burning reactor-grade plutonium. Limits in burnup due to core neutronics are investigated for this type of fuel. With these limits in mind, we study in some detail the Pu cycle in the special case of a

  3. Gas-phase saturation and evaporative cooling effects during wet compression of a fuel aerosol under RCM conditions

    SciTech Connect

    Goldsborough, S.S.; Johnson, M.V.; Zhu, G.S.; Aggarwal, S.K.

    2011-01-15

    Wet compression of a fuel aerosol has been proposed as a means of creating gas-phase mixtures of involatile diesel-representative fuels and oxidizer + diluent gases for rapid compression machine (RCM) experiments. The use of high concentration aerosols (e.g., {proportional_to}0.1 mL{sub fuel}/L{sub gas}, {proportional_to}1 x 10{sup 9} droplets/L{sub gas} for stoichiometric fuel loading at ambient conditions) can result in droplet-droplet interactions which lead to significant gas-phase fuel saturation and evaporative cooling during the volumetric compression process. In addition, localized stratification (i.e., on the droplet scale) of the fuel vapor and of temperature can lead to non-homogeneous reaction and heat release processes - features which could prevent adequate segregation of the underlying chemical kinetic rates from rates of physical transport. These characteristics are dependent on many factors including physical parameters such as overall fuel loading and initial droplet size relative to the compression rate, as well as fuel and diluent properties such as the boiling curve, vaporization enthalpy, heat capacity, and mass and thermal diffusivities. This study investigates the physical issues, especially fuel saturation and evaporative cooling effects, using a spherically-symmetric, single-droplet wet compression model. n-Dodecane is used as the fuel with the gas containing 21% O{sub 2} and 79% N{sub 2}. An overall compression time and compression ratio of 15.3 ms and 13.4 are used, respectively. It is found that smaller droplets (d{sub 0}{proportional_to} 2-3 {mu}m) are more affected by 'far-field' saturation and cooling effects, while larger droplets (d{sub 0}{proportional_to} 14 {mu}m) result in greater localized stratification of the gas-phase due to the larger diffusion distances for heat and mass transport. Vaporization of larger droplets is more affected by the volumetric compression process since evaporation requires more time to be completed

  4. Dielectric properties measurement method in the microwave frequencies range for non-polar/polar liquid mixtures characterization

    NASA Astrophysics Data System (ADS)

    Surducan, E.; Neamtu, C.; Ienciu, M.; Surducan, V.; Limare, A.; Fourel, L.

    2015-12-01

    We present a method based on dielectric properties measurements over a large spectrum of frequencies, in the microwave (MW) domain, in order to characterize a liquid mixture. The liquid mixtures consist of non-polar fluids (silicone oil, diesel fuel) and polar additives, in order to increase the specific MW absorption of the mixture for further MW power processing. We have measured the MW specific absorptions for mixtures of silicone oil with 20% and 30% (w/w) isopropanol. In both cases, the mixtures are sufficiently stable over time to allow further studies of thermal convection dynamics initiated by MW heating. For a mixture of diesel fuel with 10% (w/w) alkyl polyglycoside, the main observation was that its MW specific absorption varies over time after the mechanical mixing process.

  5. A flash vaporization system for detonation of hydrocarbon fuels in a pulse detonation engine

    NASA Astrophysics Data System (ADS)

    Tucker, Kelly Colin

    Current research by both the US Air Force and Navy is concentrating on obtaining detonations in a pulse detonation engine (PDE) with low vapor pressure, kerosene based jet fuels. These fuels, however, have a low vapor pressure and the performance of a liquid hydrocarbon fueled PDE is significantly hindered by the presence of fuel droplets. A high pressure, fuel flash vaporization system (FVS) has been designed and built to reduce and eliminate the time required to evaporate the fuel droplets. Four fuels are tested: n-heptane, isooctane, aviation gasoline, and JP-8. The fuels vary in volatility and octane number and present a clear picture on the benefits of flash vaporization. Results show the FVS quickly provided a detonable mixture for all of the fuels tested without coking or clogging the fuel lines. Combustion results validated the model used to predict the fuel and air temperatures required to achieve gaseous mixtures with each fuel. The most significant achievement of the research was the detonation of flash vaporized JP-8 and air. The results show that the flash vaporized JP-8 used 20 percent less fuel to ignite the fuel air mixture twice as fast (8 ms from 16 ms) when compared to the unheated JP-8 combustion data. Likewise, the FVS has been validated as a reliable method to create the droplet free mixtures required for liquid hydrocarbon fueled PDEs.

  6. TEA laser gas mixture optimization

    NASA Astrophysics Data System (ADS)

    Lipchak, W. Michael; Luck, Clarence F.

    1982-11-01

    The topographical plot of an optimized parameter, such as pulse energy or peak power, on the gas mixture plane is presented as a useful aid in realizing optimum mixtures of helium, carbon dioxide, and nitrogen, for operation of CO2 TEA lasers. A method for generating such a plot is discussed and an example is shown. The potential benefits of this graphical technique are also discussed.

  7. TEA laser gas mixture optimization

    SciTech Connect

    Lipchak, W.M.; Luck, C.F.

    1982-11-01

    The topographical plot of an optimized parameter, such as pulse energy or peak power, on the gas mixture plane is presented as a useful aid in realizing optimum mixtures of helium, carbon dioxide, and nitrogen, for operation of CO/sub 2/ TEA lasers. A method for generating such a plot is discussed and an example is shown. The potential benefits of this graphical technique are also discussed.

  8. SEPARATION OF GAS MIXTURES BY THERMOACOUSTIC WAVES

    SciTech Connect

    G.W. SWIFT; D.A. GELLER; P.S. SPOOR

    2001-06-01

    Imposing sound on a binary gas mixture in a duct separates the two gases along the acoustic-propagation axis. Mole-fraction differences as large as 10% and separation fluxes as high as 0.001 M-squared c, where M is Mach number and c is sound speed, are easily observed. We describe the accidental discovery of this phenomenon in a helium-xenon mixture, subsequent experiments with a helium-argon mixture, and theoretical developments. The phenomenon occurs because a thin layer of the gas adjacent to the wall is immobilized by viscosity while the rest of the gas moves back and forth with the wave, and the heat capacity of the wall holds this thin layer of the gas at constant temperature while the rest of the gas experiences temperature oscillations due to the wave's oscillating pressure. The oscillating temperature gradient causes the light and heavy atoms in the gas to take turns diffusing into and out of the immobilized layer, so that the oscillating motion of the wave outside the immobilized layer tends to carry light-enriched gas in one direction and heavy-enriched gas in the opposite direction. Experiment and theory are in very good agreement for the initial separation fluxes and the saturation mole-fraction differences.

  9. Non-Genomic Effects of Xenoestrogen Mixtures

    PubMed Central

    Viñas, René; Jeng, Yow-Jiun; Watson, Cheryl S.

    2012-01-01

    Xenoestrogens (XEs) are chemicals derived from a variety of natural and anthropogenic sources that can interfere with endogenous estrogens by either mimicking or blocking their responses via non-genomic and/or genomic signaling mechanisms. Disruption of estrogens’ actions through the less-studied non-genomic pathway can alter such functional end points as cell proliferation, peptide hormone release, catecholamine transport, and apoptosis, among others. Studies of potentially adverse effects due to mixtures and to low doses of endocrine-disrupting chemicals have recently become more feasible, though few so far have included actions via the non-genomic pathway. Physiologic estrogens and XEs evoke non-monotonic dose responses, with different compounds having different patterns of actions dependent on concentration and time, making mixture assessments all the more challenging. In order to understand the spectrum of toxicities and their mechanisms, future work should focus on carefully studying individual and mixture components across a range of concentrations and cellular pathways in a variety of tissue types. PMID:23066391

  10. Advanced thermally stable jet fuels

    SciTech Connect

    Schobert, H.H.

    1999-01-31

    The Pennsylvania State University program in advanced thermally stable coal-based jet fuels has five broad objectives: (1) Development of mechanisms of degradation and solids formation; (2) Quantitative measurement of growth of sub-micrometer and micrometer-sized particles suspended in fuels during thermal stressing; (3) Characterization of carbonaceous deposits by various instrumental and microscopic methods; (4) Elucidation of the role of additives in retarding the formation of carbonaceous solids; (5) Assessment of the potential of production of high yields of cycloalkanes by direct liquefaction of coal. Future high-Mach aircraft will place severe thermal demands on jet fuels, requiring the development of novel, hybrid fuel mixtures capable of withstanding temperatures in the range of 400--500 C. In the new aircraft, jet fuel will serve as both an energy source and a heat sink for cooling the airframe, engine, and system components. The ultimate development of such advanced fuels requires a thorough understanding of the thermal decomposition behavior of jet fuels under supercritical conditions. Considering that jet fuels consist of hundreds of compounds, this task must begin with a study of the thermal degradation behavior of select model compounds under supercritical conditions. The research performed by The Pennsylvania State University was focused on five major tasks that reflect the objectives stated above: Task 1: Investigation of the Quantitative Degradation of Fuels; Task 2: Investigation of Incipient Deposition; Task 3: Characterization of Solid Gums, Sediments, and Carbonaceous Deposits; Task 4: Coal-Based Fuel Stabilization Studies; and Task 5: Exploratory Studies on the Direct Conversion of Coal to High Quality Jet Fuels. The major findings of each of these tasks are presented in this executive summary. A description of the sub-tasks performed under each of these tasks and the findings of those studies are provided in the remainder of this volume

  11. Heat exchanger for fuel cell power plant reformer

    DOEpatents

    Misage, Robert; Scheffler, Glenn W.; Setzer, Herbert J.; Margiott, Paul R.; Parenti, Jr., Edmund K.

    1988-01-01

    A heat exchanger uses the heat from processed fuel gas from a reformer for a fuel cell to superheat steam, to preheat raw fuel prior to entering the reformer and to heat a water-steam coolant mixture from the fuel cells. The processed fuel gas temperature is thus lowered to a level useful in the fuel cell reaction. The four temperature adjustments are accomplished in a single heat exchanger with only three heat transfer cores. The heat exchanger is preheated by circulating coolant and purge steam from the power section during startup of the latter.

  12. Effect of sunflower oil on a diesel fuel system

    SciTech Connect

    Kucera, H.; Schunk, S.; Pratt, G.

    1982-05-01

    A typical farm tractor diesel fuel system (injection pump, fuel lines, filters and injectors) was tested on a test stand at various temperatures using sunflower oil, diesel fuel, and mixtures of the two as fuels. Measurements taken included fuel volume delivered by the injector line pressure at the injector, pressure drop across the filter, transfer pump pressure, and fuel injection timing. Results indicate that low percentages of sunflower oil may be used successfully in the system under summer conditions. Design changes to the system may be necessary for higher percentages of sunflower oil and cold conditions.

  13. Cholestatic hepatitis due to Ecballium elaterium ingestion.

    PubMed

    Bizid, Sondès; Sabbah, Mériam; Msakni, Issam; Ben Slimene, Baha; Mohamed, Ghanem; Bouali, Riadh; Ben Abdallah, Hatem; Abdelli, Nabil

    2015-10-01

    Ecballium elaterium is an herbaceous plant belonging to the Cucurbitaceae family. This plant is fairly common in the Mediterranean regions. It is frequently consumed in infusion, mixture of fruit or even in aerosol in cases of fever or flu. This plant is known for its respiratory and ocular toxicity. Hepatotoxicity has never been described in the literature. We report a case of acute cholestatic hepatitis due to Ecballium elaterium in a 39 years old patient, with no past medical history.

  14. Improving the AGR Fuel Testing Power Density Profile Versus Irradiation-Time in the Advanced Test Reactor

    SciTech Connect

    Gray S. Chang; David A. Petti; John T. Maki; Misti A. Lillo

    2009-05-01

    The Very High Temperature gas-cooled Reactor (VHTR), which is currently being developed, achieves simplification of safety through reliance on ceramic-coated fuel particles. Each TRISO-coated fuel particle has its own containment which serves as the principal barrier against radionuclide release under normal operating and accident conditions. These fuel particles, in the form of graphite fuel compacts, are currently undergoing a series of irradiation tests in the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL) to support the Advanced Gas-Cooled Reactor (AGR) fuel qualification program. A representive coated fuel particle with an 235U enrichment of 19.8 wt% was used in this analysis. The fuel burnup analysis tool used to perform the neutronics study reported herein, couples the Monte Carlo transport code MCNP, with the radioactive decay and burnup code ORIGEN2. The fuel burnup methodology known as Monte-Carlo with ORIGEN2 (MCWO) was used to evaluate the AGR experiment assembly and demonstrate compliance with ATR safety requirements. For the AGR graphite fuel compacts, the MCWO-calculated fission power density (FPD) due to neutron fission in 235U is an important design parameter. One of the more important AGR fuel testing requirements is to maintain the peak fuel compact temperature close to 1250°C throughout the proposed irradiation campaign of 550 effective full power days (EFPDs). Based on the MCWO-calculated FPD, a fixed gas gap size was designed to allow regulation of the fuel compact temperatures throughout the entire fuel irradiation campaign by filling the gap with a mixture of helium and neon gases. The chosen fixed gas gap can only regulate the peak fuel compact temperature in the desired range during the irradiation test if the ratio of the peak power density to the time-dependent low power density (P/T) at 550 EFPDs is less than 2.5. However, given the near constant neutron flux within the ATR driver core and the depletion of 235U in

  15. Gaseous fueled torch apparatus and fueling module therefor

    SciTech Connect

    Czerwinski, K.S.; Gabany, E.; Sharma, S.S.; Turko, J.W.

    1988-10-11

    This patent describes a fueling module for supplying natural gas to a natural gas fueled torch apparatus including a torch adapted for use in cutting or welding operations, the torch apparatus further including a source of oxygen for supplying oxygen to the torch, and the torch being selectively operable for combustion of a mixture of natural gas and oxygen, the fueling module connectable to an electric power source and being supplying natural gas to the torch apparatus at an elevated pressure from a relatively low pressure natural gas supply system, the fueling module comprising: fueling module inlet means connectable in fluid communication with the natural gas supply system; compression means in fluid communication with the fueling module inlet means and selectively energizable for compressing the natural gas from the natural gas supply system in order to increase its pressure, the compression means having a compression intake in fluid communication with the fueling module inlet means and a compression discharge outlet for discharging compressed natural gas from the compression means; lubricant filter means in fluid communication with the compression discharge outlet for substantially trapping and collecting compression means lubricants from the compressed natural gas from the compression discharge outlet and for returning the collected compression means lubricants to the compression intake; cooling means in fluid communication with the compression discharge outlet means for reducing the temperature of the compressed natural gas.

  16. Spin-Drag Hall Effect in a Rotating Bose Mixture

    SciTech Connect

    Driel, H. J. van; Duine, R. A.; Stoof, H. T. C.

    2010-10-08

    We show that in a rotating two-component Bose mixture, the spin drag between the two different spin species shows a Hall effect. This spin-drag Hall effect can be observed experimentally by studying the out-of-phase dipole mode of the mixture. We determine the damping of this mode due to spin drag as a function of temperature. We find that due to Bose stimulation there is a strong enhancement of the damping for temperatures close to the critical temperature for Bose-Einstein condensation.

  17. Universal Three-Body Physics in Ultracold KRb Mixtures

    NASA Astrophysics Data System (ADS)

    Wacker, L. J.; Jørgensen, N. B.; Birkmose, D.; Winter, N.; Mikkelsen, M.; Sherson, J.; Zinner, N.; Arlt, J. J.

    2016-10-01

    Ultracold atomic gases have recently become a driving force in few-body physics due to the observation of the Efimov effect. While initially observed in equal mass systems, one expects even richer few-body physics in the heteronuclear case. In previous experiments with ultracold mixtures of potassium and rubidium, an unexpected nonuniversal behavior of Efimov resonances was observed. In contrast, we measure the scattering length dependent three-body recombination coefficient in ultracold heteronuclear mixtures of 39K - 87Rb and 41K - 87Rb and do not observe any signatures of Efimov resonances for accessible scattering lengths in either mixture. Our results show good agreement with our theoretical model for the scattering dependent three-body recombination coefficient and reestablish universality across isotopic mixtures.

  18. Benzophenone derivatives as fuel additives

    SciTech Connect

    Andress, H.J.

    1988-05-17

    This patent describes a composition comprising a major amount of a liquid hydrocarbon fuel having an initial boiling point of at least about 75/sup 0/F and an end boiling point of about 750/sup 0/F, and a minor amount sufficient to improve the fuel detergency thereof the reaction product of an ester of a benzophenone tetracarboxylic dianhydride or mixtures of such esters and an amine wherein the benzophenone tetracarboxylic dianhydride ester or mixtures of such esters are reacted with the amine in a mole ratio of from about 3:1 to about 1:3 at a temperature of from about 100/sup 0/ - 300/sup 0/C at atmospheric pressure from about three to about 10 hours.

  19. Modeling fuel succession

    USGS Publications Warehouse

    Davis, Brett; Van Wagtendonk, Jan W.; Beck, Jen; van Wagtendonk, Kent A.

    2009-01-01

    Surface fuels data are of critical importance for supporting fire incident management, risk assessment, and fuel management planning, but the development of surface fuels data can be expensive and time consuming. The data development process is extensive, generally beginning with acquisition of remotely sensed spatial data such as aerial photography or satellite imagery (Keane and others 2001). The spatial vegetation data are then crosswalked to a set of fire behavior fuel models that describe the available fuels (the burnable portions of the vegetation) (Anderson 1982, Scott and Burgan 2005). Finally, spatial fuels data are used as input to tools such as FARSITE and FlamMap to model current and potential fire spread and behavior (Finney 1998, Finney 2006). The capture date of the remotely sensed data defines the period for which the vegetation, and, therefore, fuels, data are most accurate. The more time that passes after the capture date, the less accurate the data become due to vegetation growth and processes such as fire. Subsequently, the results of any fire simulation based on these data become less accurate as the data age. Because of the amount of labor and expense required to develop these data, keeping them updated may prove to be a challenge. In this article, we describe the Sierra Nevada Fuel Succession Model, a modeling tool that can quickly and easily update surface fuel models with a minimum of additional input data. Although it was developed for use by Yosemite, Sequoia, and Kings Canyon National Parks, it is applicable to much of the central and southern Sierra Nevada. Furthermore, the methods used to develop the model have national applicability.

  20. Hydrogen vehicle fueling station

    SciTech Connect

    Daney, D.E.; Edeskuty, F.J.; Daugherty, M.A.

    1995-09-01

    Hydrogen fueling stations are an essential element in the practical application of hydrogen as a vehicle fuel, and a number of issues such as safety, efficiency, design, and operating procedures can only be accurately addressed by a practical demonstration. Regardless of whether the vehicle is powered by an internal combustion engine or fuel cell, or whether the vehicle has a liquid or gaseous fuel tank, the fueling station is a critical technology which is the link between the local storage facility and the vehicle. Because most merchant hydrogen delivered in the US today (and in the near future) is in liquid form due to the overall economics of production and delivery, we believe a practical refueling station should be designed to receive liquid. Systems studies confirm this assumption for stations fueling up to about 300 vehicles. Our fueling station, aimed at refueling fleet vehicles, will receive hydrogen as a liquid and dispense it as either liquid, high pressure gas, or low pressure gas. Thus, it can refuel any of the three types of tanks proposed for hydrogen-powered vehicles -- liquid, gaseous, or hydride. The paper discusses the fueling station design. Results of a numerical model of liquid hydrogen vehicle tank filling, with emphasis on no vent filling, are presented to illustrate the usefulness of the model as a design tool. Results of our vehicle performance model illustrate our thesis that it is too early to judge what the preferred method of on-board vehicle fuel storage will be in practice -- thus our decision to accommodate all three methods.

  1. Effect of NACA Injection Impeller on Mixture Distribution of Double-Row Radial Aircraft Engine

    NASA Technical Reports Server (NTRS)

    Marble, Frank E; Ritter, William K; Miller, Mahlon A

    1945-01-01

    The NACA injection impeller was developed to improve the mixture distribution of aircraft engines by discharging the fuel from a centrifugal supercharger impeller and thus to promote a thorough mixing of fuel and charge air. Experiments with a double-row radial aircraft engine indicated that for the normal range of engine power the NACA injection impeller provided marked improvement in mixture distribution over the standard spray-bar injection system used in the same engine. The mixture distribution at cruising conditions was excellent; at 1200, 1500, and 1700 brake horsepower, the differences between the fuel-air ratios of the richest and the leanest cylinders were reduced to approximately one-third their former values.

  2. FUEL COMPOSITION FOR NUCLEAR REACTORS

    DOEpatents

    Andersen, J.C.

    1963-08-01

    A process for making refractory nuclear fuel elements involves heating uranium and silicon powders in an inert atmosphere to 1600 to 1800 deg C to form USi/sub 3/; adding silicon carbide, carbon, 15% by weight of nickel and aluminum, and possibly also molybdenum and silicon powders; shaping the mixture; and heating to 1700 to 2050 deg C again in an inert atmosphere. Information on obtaining specific compositions is included. (AEC)

  3. Effects of Non-Uniform Fuel Distribution on Detonation Tube Performance

    NASA Technical Reports Server (NTRS)

    Perkins, H. Douglas; Sung, Chih-Jen

    2003-01-01

    A pulse detonation engine uses a series of high frequency intermittent detonation tubes to generate thrust. The process of filling the detonation tube with fuel and air for each cycle may yield non-uniform mixtures. Uniform mixing is commonly assumed when calculating detonation tube thrust performance. In this study, detonation cycles featuring idealized non-uniform H2/air mixtures were analyzed using a two-dimensional Navier-Stokes computational fluid dynamics code with detailed chemistry. Mixture non-uniformities examined included axial equivalence ratio gradients, transverse equivalence ratio gradients, and partially fueled tubes. Three different average test section equivalence ratios were studied; one stoichiometric, one fuel lean, and one fuel rich. All mixtures were detonable throughout the detonation tube. Various mixtures representing the same average test section equivalence ratio were shown to have specific impulses within 1% of each other, indicating that good fuel/air mixing is not a prerequisite for optimal detonation tube performance under the conditions investigated.

  4. Orbiter fuel cell improvement assessment

    NASA Technical Reports Server (NTRS)

    Johnson, R. E.

    1981-01-01

    The history of fuel cells and the theory of fuel cells is given. Expressions for thermodynamic and electrical efficiencies are developed. The voltage losses due to electrode activation, ohmic resistance and ionic diffusion are discussed. Present limitations of the Orbiter Fuel Cell, as well as proposed enhancements, are given. These enhancements are then evaluated and recommendations are given for fuel cell enhancement both for short-range as well as long-range performance improvement. Estimates of reliability and cost savings are given for enhancements where possible.

  5. 40 CFR 600.113-12 - Fuel economy and carbon-related exhaust emission calculations for FTP, HFET, US06, SC03 and cold...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) divided by the total weight of fuel. (4) Ethanol test fuel shall be analyzed to determine the following...-fueled automobiles and automobiles designed to operate on mixtures of gasoline and ethanol, the fuel... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Fuel economy and...

  6. Reflectance properties of spinel-plagioclase mixtures

    NASA Astrophysics Data System (ADS)

    Cheek, L.; Jackson, C.; Dhingra, D.; Pieters, C. M.; Prissel, T. C.; Williams, K. B.

    2012-12-01

    Near-infrared spectra displaying the diagnostic properties of Mg-spinel have recently been reported in several lunar craters based on Moon Mineralogy Mapper (M3) data [1-5]. These spectra lack evidence for olivine or pyroxene, suggesting that they represent a spinel-plagioclase lithology [1]. Current hypotheses [6, 7] suggest that this lithology formed by interactions of a mafic or ultramafic liquid with an anorthositic country rock, but the proportions of spinel and plagioclase are unknown. The aim of this work is to constrain the modal abundances of spinel and plagioclase in the observed lithology using laboratory reflectance spectroscopy of particulate mixtures. Reflectance spectra of Mg-spinel display a strong absorption at ~2000 nm due to Fe2+ in a tetrahedral site [e.g., 8]. At higher FeO contents, > ~5 wt%, an octahedral absorption near 1000 nm is also apparent [9]. Plagioclase often displays a broad absorption centered near 1250 nm due to trace amounts (0.1 wt%) of Fe2+ in the Ca2+ site. Previous studies have noted that plagioclase must be present in extremely high abundances (~85 vol%) in order for the 1250 nm absorption to be apparent in mixtures with olivine and pyroxene [10, 11]. Recent nonlinear modeling has suggested that at least 50% plagioclase is necessary for the 1250 nm absorption to be apparent in a calculated mixture with spinel [12]. Our approach involves making mineral mixtures of spinel and plagioclase particulate samples and measuring near-infrared spectra of the bulk material. For the plagioclase endmember, we use terrestrial gem quality labradorite with ~0.3 wt% FeO. The spinel endmember was produced experimentally at Brown University (1500 C; fO2~ IW; sintered 72 hrs), and contains 5 wt% FeO. Preliminary results show that spectra of a 90% plagioclase - 10% spinel mixture only display the spectral properties of the spinel component; the 1250 nm absorption is not apparent. Importantly, the addition of 90% plagioclase does not significantly

  7. Variational Inference for Watson Mixture Model.

    PubMed

    Taghia, Jalil; Leijon, Arne

    2016-09-01

    This paper addresses modelling data using the Watson distribution. The Watson distribution is one of the simplest distributions for analyzing axially symmetric data. This distribution has gained some attention in recent years due to its modeling capability. However, its Bayesian inference is fairly understudied due to difficulty in handling the normalization factor. Recent development of Markov chain Monte Carlo (MCMC) sampling methods can be applied for this purpose. However, these methods can be prohibitively slow for practical applications. A deterministic alternative is provided by variational methods that convert inference problems into optimization problems. In this paper, we present a variational inference for Watson mixture models. First, the variational framework is used to side-step the intractability arising from the coupling of latent states and parameters. Second, the variational free energy is further lower bounded in order to avoid intractable moment computation. The proposed approach provides a lower bound on the log marginal likelihood and retains distributional information over all parameters. Moreover, we show that it can regulate its own complexity by pruning unnecessary mixture components while avoiding over-fitting. We discuss potential applications of the modeling with Watson distributions in the problem of blind source separation, and clustering gene expression data sets. PMID:26571512

  8. Electrolyte reservoir for carbonate fuel cells

    DOEpatents

    Iacovangelo, C.D.; Shores, D.A.

    1984-05-23

    An electrode for a carbonate fuel cell and method of making same are described wherein a substantially uniform mixture of an electrode-active powder and porous ceramic particles suitable for a carbonate fuel cell are formed into an electrode with the porous ceramic particles having pores in the range of from about 1 micron to about 3 microns, and a carbonate electrolyte is in the pores of the ceramic particles.

  9. Electrolyte reservoir for carbonate fuel cells

    DOEpatents

    Iacovangelo, Charles D.; Shores, David A.

    1985-01-01

    An electrode for a carbonate fuel cell and method of making same wherein a substantially uniform mixture of an electrode-active powder and porous ceramic particles suitable for a carbonate fuel cell are formed into an electrode with the porous ceramic particles having pores in the range of from about 1 micron to about 3 microns, and a carbonate electrolyte is in the pores of the ceramic particles.

  10. Methane-free biogas for direct feeding of solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Leone, P.; Lanzini, A.; Santarelli, M.; Calì, M.; Sagnelli, F.; Boulanger, A.; Scaletta, A.; Zitella, P.

    This paper deals with the experimental analysis of the performance and degradation issues of a Ni-based anode-supported solid oxide fuel cell fed by a methane-free biogas from dark-anaerobic digestion of wastes by pastry and fruit shops. The biogas is produced by means of an innovative process where the biomass is fermented with a pre-treated bacteria inoculum (Clostridia) able to completely inhibit the methanization step during the fermentation process and to produce a H 2/CO 2 mixture instead of conventional CH 4/CO 2 anaerobic digested gas (bio-methane). The proposed biogas production route leads to a biogas composition which avoids the need of introducing a reformer agent into or before the SOFC anode in order to reformate it. In order to analyse the complete behaviour of a SOFC with the bio-hydrogen fuel, an experimental session with several H 2/CO 2 synthetic mixtures was performed on an anode-supported solid oxide fuel cell with a Ni-based anode. It was found that side reactions occur with such mixtures in the typical thermodynamic conditions of SOFCs (650-800 °C), which have an effect especially at high currents, due to the shift to a mixture consisting of hydrogen, carbon monoxide, carbon dioxide and water. However, cells operated with acceptable performance and carbon deposits (typical of a traditional hydrocarbon-containing biogas) were avoided after 50 h of cell operation even at 650 °C. Experiments were also performed with traditional bio-methane from anaerobic digestion with 60/40 vol% of composition. It was found that the cell performance dropped after few hours of operation due to the formation of carbon deposits. A short-term test with the real as-produced biogas was also successfully performed. The cell showed an acceptable power output (at 800 °C, 0.35 W cm -2 with biogas, versus 0.55 W cm -2 with H 2) although a huge quantity of sulphur was present in the feeding fuel (hydrogen sulphide at 103 ppm and mercaptans up to 10 ppm). Therefore, it

  11. Automated Fuel Element Closure Welding System

    SciTech Connect

    Wahlquist, D.R.

    1993-01-01

    The Automated Fuel Element Closure Welding System is a robotic device that will load and weld top end plugs onto nuclear fuel elements in a highly radioactive and inert gas environment. The system was developed at Argonne National Laboratory-West as part of the Fuel Cycle Demonstration. The welding system performs four main functions, it (1) injects a small amount of a xenon/krypton gas mixture into specific fuel elements, and (2) loads tiny end plugs into the tops of fuel element jackets, and (3) welds the end plugs to the element jackets, and (4) performs a dimensional inspection of the pre- and post-welded fuel elements. The system components are modular to facilitate remote replacement of failed parts. The entire system can be operated remotely in manual, semi-automatic, or fully automatic modes using a computer control system. The welding system is currently undergoing software testing and functional checkout.

  12. Automated Fuel Element Closure Welding System

    SciTech Connect

    Wahlquist, D.R.

    1993-03-01

    The Automated Fuel Element Closure Welding System is a robotic device that will load and weld top end plugs onto nuclear fuel elements in a highly radioactive and inert gas environment. The system was developed at Argonne National Laboratory-West as part of the Fuel Cycle Demonstration. The welding system performs four main functions, it (1) injects a small amount of a xenon/krypton gas mixture into specific fuel elements, and (2) loads tiny end plugs into the tops of fuel element jackets, and (3) welds the end plugs to the element jackets, and (4) performs a dimensional inspection of the pre- and post-welded fuel elements. The system components are modular to facilitate remote replacement of failed parts. The entire system can be operated remotely in manual, semi-automatic, or fully automatic modes using a computer control system. The welding system is currently undergoing software testing and functional checkout.

  13. Real gas properties and Space Shuttle Main Engine fuel turbine performance prediction

    NASA Technical Reports Server (NTRS)

    Harloff, G. J.

    1987-01-01

    The H2/H2O mixture thermodynamic and transport properties variations for the Space Shuttle Main Engine (SSME) fuel turbine over a range of temperatures and pressures are examined. The variation of molecular viscosity, specific heat at constant pressure, and Prandtl number for the hydrogen/steam mixture are fitted using polynominal relationships for future turbine performance use. The mixture property variations are calculated using GASP and WASP computer programs. The air equivalent performance of the SSME fuel turbine is computed.

  14. Fuel cells 101

    SciTech Connect

    Hirschenhofer, J.H.

    1999-07-01

    This paper discusses the various types of fuel cells, the importance of cell voltage, fuel processing for natural gas, cell stacking, fuel cell plant description, advantages and disadvantages of the types of fuel cells, and applications. The types covered include: polymer electrolyte fuel cell, alkaline fuel cell, phosphoric acid fuel cell; molten carbonate fuel cell, and solid oxide fuel cell.

  15. Bayesian Kernel Mixtures for Counts

    PubMed Central

    Canale, Antonio; Dunson, David B.

    2011-01-01

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

  16. Bayesian Kernel Mixtures for Counts.

    PubMed

    Canale, Antonio; Dunson, David B

    2011-12-01

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

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

    PubMed

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

    2015-01-01

    Minimum ignition energies (MIE) of α-pinene-benzene/air mixtures at a given temperature for different equivalence ratios and fuel proportions are experimented in this paper. We used a cylindrical chamber of combustion using a nanosecond pulse at 1,064 nm from a Q-switched Nd:YAG laser. Laser-induced spark ignitions were studied for two molar proportions of α-pinene/benzene mixtures, respectively 20-80% and 50-50%. The effect of the equivalence ratio (Φ) has been investigated for 0.7, 0.9, 1.1 and 1.5 and ignition of fuel/air mixtures has been experimented for two different incident laser energies: 25 and 33 mJ. This study aims at observing the influence of different α-pinene/benzene proportions on the flammability of the mixture to have further knowledge of the potential of biogenic volatile organic compounds (BVOCs) and smoke mixtures to influence forest fires, especially in the case of the accelerating forest fire phenomenon (AFF). Results of ignition probability and energy absorption are based on 400 laser shots for each studied fuel proportions. MIE results as functions of equivalence ratio compared to data of pure α-pinene and pure benzene demonstrate that the presence of benzene in α-pinene-air mixture tends to increase ignition probability and reduce MIE without depending strongly on the α-pinene/benzene proportion. PMID:25464289

  18. Effect of silane concentration on the supersonic combustion of a silane/methane mixture

    SciTech Connect

    Northam, G.B.; Mc Lain, A.G.; Pellett, G.L.; Diskin, G.S.

    1986-01-01

    A series of direct connect combustor tests was conducted to determine the effect of silane concentration on the supersonic combustion characteristics of silane/methane mixtures. Shock tube ignition delay data indicated more than an order of magnitude reduction in ignition delay times for both 10 and 20 percent silane/methane mixtures as compared to methane. The ignition delay time of the 10 percent mixture was only a factor of 2.3 greater than that of the 20 percent mixture. Supersonic combustion tests were conducted with the fuel injected into a model scramjet combustor. The combustor was mounted at the exit of a Mach 2 nozzle and a hydrogen fired heater was used to provide a variation in test gas total temperature. Tests using the 20 percent silane/methane mixture indicated considerable combustion enhancement when compared to methane alone. This mixture had an autoignition total temperature of 1650 R. The addition of 20 percent silane to methane resulted in a pyrophoric fuel with good supersonic combustion performance. Reducing the silane concentration below this level, however, yielded a less pyrophoric fuel that exhibited poor supersonic combustion performance.

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

    PubMed

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

    2015-01-01

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

  20. Nuclear fuel particles and method of making nuclear fuel compacts therefrom

    DOEpatents

    DeVelasco, Rubin I.; Adams, Charles C.

    1991-01-01

    Methods for making nuclear fuel compacts exhibiting low heavy metal contamination and fewer defective coatings following compact fabrication from a mixture of hardenable binder, such as petroleum pitch, and nuclear fuel particles having multiple layer fission-product-retentive coatings, with the dense outermost layer of the fission-product-retentive coating being surrounded by a protective overcoating, e.g., pyrocarbon having a density between about 1 and 1.3 g/cm.sup.3. Such particles can be pre-compacted in molds under relatively high pressures and then combined with a fluid binder which is ultimately carbonized to produce carbonaceous nuclear fuel compacts having relatively high fuel loadings.

  1. Mixtures as a fungicide resistance management tactic.

    PubMed

    van den Bosch, Frank; Paveley, Neil; van den Berg, Femke; Hobbelen, Peter; Oliver, Richard

    2014-12-01

    We have reviewed the experimental and modeling evidence on the use of mixtures of fungicides of differing modes of action as a resistance management tactic. The evidence supports the following conclusions. 1. Adding a mixing partner to a fungicide that is at-risk of resistance (without lowering the dose of the at-risk fungicide) reduces the rate of selection for fungicide resistance. This holds for the use of mixing partner fungicides that have either multi-site or single-site modes of action. The resulting predicted increase in the effective life of the at-risk fungicide can be large enough to be of practical relevance. The more effective the mixing partner (due to inherent activity and/or dose), the larger the reduction in selection and the larger the increase in effective life of the at-risk fungicide. 2. Adding a mixing partner while lowering the dose of the at-risk fungicide reduces the selection for fungicide resistance, without compromising effective disease control. The very few studies existing suggest that the reduction in selection is more sensitive to lowering the dose of the at-risk fungicide than to increasing the dose of the mixing partner. 3. Although there are very few studies, the existing evidence suggests that mixing two at-risk fungicides is also a useful resistance management tactic. The aspects that have received too little attention to draw generic conclusions about the effectiveness of fungicide mixtures as resistance management strategies are as follows: (i) the relative effect of the dose of the two mixing partners on selection for fungicide resistance, (ii) the effect of mixing on the effective life of a fungicide (the time from introduction of the fungicide mode of action to the time point where the fungicide can no longer maintain effective disease control), (iii) polygenically determined resistance, (iv) mixtures of two at-risk fungicides, (v) the emergence phase of resistance evolution and the effects of mixtures during this phase

  2. Unrestricted Mixture Models for Class Identification in Growth Mixture Modeling

    ERIC Educational Resources Information Center

    Liu, Min; Hancock, Gregory R.

    2014-01-01

    Growth mixture modeling has gained much attention in applied and methodological social science research recently, but the selection of the number of latent classes for such models remains a challenging issue, especially when the assumption of proper model specification is violated. The current simulation study compared the performance of a linear…

  3. Effect of fuel aromaticity on diesel emissions

    SciTech Connect

    Barbella, R.; Ciajolo, A.; D'Anna, A. ); Bertoli, C. )

    1989-09-01

    The effect of the fuel aromatic content on soot and heavy hydrocarbon emissions from a single-cylinder direct-injection diesel engine has been investigated burning a pure paraffinic fuel (n-tetradecane), a tetradecane-toluene mixture (70-30 vol%) and two diesel oils with different aromatic content. All experiments were at various air-fuel ratios with constant engine speed and injection timing advance. The detailed chemical analysis of exhaust heavy hydrocarbons in terms of mass percentage of paraffins, monoaromatics, polyaromatics and polar compounds, and the gas chromatography-mass spectrometry of each hydrocarbon class have been compared with the original fuel analyses in order to discriminate the unburned fuel compounds from the combustion-formed products. The soot emission rate has been found to be independent of the fuel aromatic content, but the fuel affects the quality and quantity of heavy hydrocarbon emission. Low amounts of heavy hydrocarbons, mainly partially oxidized compounds, are emitted from tetradecane combustion, whereas diesel fuel oils produced high emissions of heavy hydrocarbons, mainly unburned fuel compounds. The emission of polynuclear aromatic hydrocarbons (PAH) from tetradecane and tetradecane-toluene diesel combustion indicates that these compounds are combustion-formed products, but unburned fuel PAH are the main components of PAH emitted by the diesel fuel oils.

  4. Landfilling ash/sludge mixtures

    SciTech Connect

    Benoit, J.; Eighmy, T.T.; Crannell, B.S.

    1999-10-01

    The geotechnical properties of a mixture of municipal solid waste incinerator bottom ash and municipal wastewater treatment plant sludge was investigated for a proposed ash/sludge secure landfill. The components as well as mixtures ranging from 10:1 to 5:1 (ash:sludge, by volume) were evaluated, where appropriate, for a number of geotechnical index and mechanical properties including particle size, water content, specific gravity, density-moisture relationships, shear strength, and compressibility. The results from a compactibility study and stability analysis of the proposed landfill were used to help approve a landfill codisposal concept; a full-scale facility was constructed and is currently operating successfully.

  5. Phylogenetic mixture models for proteins.

    PubMed

    Le, Si Quang; Lartillot, Nicolas; Gascuel, Olivier

    2008-12-27

    Standard protein substitution models use a single amino acid replacement rate matrix that summarizes the biological, chemical and physical properties of amino acids. However, site evolution is highly heterogeneous and depends on many factors: genetic code; solvent exposure; secondary and tertiary structure; protein function; etc. These impact the substitution pattern and, in most cases, a single replacement matrix is not enough to represent all the complexity of the evolutionary processes. This paper explores in maximum-likelihood framework phylogenetic mixture models that combine several amino acid replacement matrices to better fit protein evolution.We learn these mixture models from a large alignment database extracted from HSSP, and test the performance using independent alignments from TREEBASE.We compare unsupervised learning approaches, where the site categories are unknown, to supervised ones, where in estimations we use the known category of each site, based on its exposure or its secondary structure. All our models are combined with gamma-distributed rates across sites. Results show that highly significant likelihood gains are obtained when using mixture models compared with the best available single replacement matrices. Mixtures of matrices also improve over mixtures of profiles in the manner of the CAT model. The unsupervised approach tends to be better than the supervised one, but it appears difficult to implement and highly sensitive to the starting values of the parameters, meaning that the supervised approach is still of interest for initialization and model comparison. Using an unsupervised model involving three matrices, the average AIC gain per site with TREEBASE test alignments is 0.31, 0.49 and 0.61 compared with LG (named after Le & Gascuel 2008 Mol. Biol. Evol. 25, 1307-1320), WAG and JTT, respectively. This three-matrix model is significantly better than LG for 34 alignments (among 57), and significantly worse for 1 alignment only. Moreover

  6. Testing of high-octane fuels in the single-cylinder airplane engine

    NASA Technical Reports Server (NTRS)

    Seeber, Fritz

    1940-01-01

    One of the most important properties of aviation fuels for spark-ignition engines is their knock rating. The CFR engine tests of fuels of 87 octane and above does not always correspond entirely to the actual behavior of these fuels in the airplane engine. A method is therefore developed which, in contrast to the octane number determination, permits a testing of the fuel under various temperatures and fuel mixture conditions. The following reference fuels were employed: 1) Primary fuels; isooctane and n-heptane; 2) Secondary fuels; pure benzene and synthetic benzine.

  7. 16 CFR 1500.5 - Hazardous mixtures.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Hazardous mixtures. 1500.5 Section 1500.5... HAZARDOUS SUBSTANCES AND ARTICLES; ADMINISTRATION AND ENFORCEMENT REGULATIONS § 1500.5 Hazardous mixtures. For a mixture of substances, the determination of whether the mixture is a “hazardous substance”...

  8. 14 CFR 23.1147 - Mixture controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Mixture controls. 23.1147 Section 23.1147... Accessories § 23.1147 Mixture controls. (a) If there are mixture controls, each engine must have a separate control, and each mixture control must have guards or must be shaped or arranged to prevent confusion...

  9. 16 CFR 1500.5 - Hazardous mixtures.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Hazardous mixtures. 1500.5 Section 1500.5... HAZARDOUS SUBSTANCES AND ARTICLES; ADMINISTRATION AND ENFORCEMENT REGULATIONS § 1500.5 Hazardous mixtures. For a mixture of substances, the determination of whether the mixture is a “hazardous substance”...

  10. 14 CFR 23.1147 - Mixture controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Mixture controls. 23.1147 Section 23.1147... Accessories § 23.1147 Mixture controls. (a) If there are mixture controls, each engine must have a separate control, and each mixture control must have guards or must be shaped or arranged to prevent confusion...

  11. 16 CFR 1500.5 - Hazardous mixtures.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Hazardous mixtures. 1500.5 Section 1500.5... HAZARDOUS SUBSTANCES AND ARTICLES; ADMINISTRATION AND ENFORCEMENT REGULATIONS § 1500.5 Hazardous mixtures. For a mixture of substances, the determination of whether the mixture is a “hazardous substance”...

  12. 14 CFR 23.1147 - Mixture controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Mixture controls. 23.1147 Section 23.1147... Accessories § 23.1147 Mixture controls. (a) If there are mixture controls, each engine must have a separate control, and each mixture control must have guards or must be shaped or arranged to prevent confusion...

  13. 14 CFR 23.1147 - Mixture controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Mixture controls. 23.1147 Section 23.1147... Accessories § 23.1147 Mixture controls. (a) If there are mixture controls, each engine must have a separate control, and each mixture control must have guards or must be shaped or arranged to prevent confusion...

  14. 16 CFR 1500.5 - Hazardous mixtures.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Hazardous mixtures. 1500.5 Section 1500.5... HAZARDOUS SUBSTANCES AND ARTICLES; ADMINISTRATION AND ENFORCEMENT REGULATIONS § 1500.5 Hazardous mixtures. For a mixture of substances, the determination of whether the mixture is a “hazardous substance”...

  15. 14 CFR 23.1147 - Mixture controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Mixture controls. 23.1147 Section 23.1147... Accessories § 23.1147 Mixture controls. (a) If there are mixture controls, each engine must have a separate control, and each mixture control must have guards or must be shaped or arranged to prevent confusion...

  16. 16 CFR 1500.5 - Hazardous mixtures.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Hazardous mixtures. 1500.5 Section 1500.5... HAZARDOUS SUBSTANCES AND ARTICLES; ADMINISTRATION AND ENFORCEMENT REGULATIONS § 1500.5 Hazardous mixtures. For a mixture of substances, the determination of whether the mixture is a “hazardous substance”...

  17. Analysis of Cylinder-pressure-indicator Diagrams Showing Effects of Mixture Strength and Spark Timing

    NASA Technical Reports Server (NTRS)

    Gerrish, Harold C; Voss, Fred

    1940-01-01

    An investigation was made to determine the effect of mixture strength and of normal as well as optimum spark timing on the combustion, on the cylinder temperature, and on the performance characteristics of an engine. A single-cylinder test unit utilizing an air-cooled cylinder and a carburetor and operating with gasoline having an octane rating of 92 was used. The investigation covered a range of fuel-air ratios from 0.053 to 0.118. Indicator diagrams and engine-performance data were taken for each change in engine conditions. Examination of the indicator shows that for fuel-air ratios less than and greater than 0.082 the rate and the amount of effective fuel burned decreased. For a fuel-air ratio of 0.118 the combustion efficiency was only 58 percent. Advancing the spark timing increased the rate of pressure rise. This effect was more pronounced with leaner mixtures.

  18. Precursor detonation wave development in ANFO due to aluminum confinement

    SciTech Connect

    Jackson, Scott I; Klyanda, Charles B; Short, Mark

    2010-01-01

    Detonations in explosive mixtures of ammonium-nitrate-fuel-oil (ANFO) confined by aluminum allow for transport of detonation energy ahead of the detonation front due to the aluminum sound speed exceeding the detonation velocity. The net effect of this energy transport on the detonation is unclear. It could enhance the detonation by precompressing the explosive near the wall. Alternatively, it could decrease the explosive performance by crushing porosity required for initiation by shock compression or destroying confinement ahead of the detonation. At present, these phenomena are not well understood. But with slowly detonating, non-ideal high explosive (NIHE) systems becoming increasing prevalent, proper understanding and prediction of the performance of these metal-confined NIHE systems is desirable. Experiments are discussed that measured the effect of this ANFO detonation energy transported upstream of the front by a 76-mm-inner-diameter aluminum confining tube. Detonation velocity, detonation-front shape, and aluminum response are recorded as a function of confiner wall thickness and length. Detonation shape profiles display little curvature near the confining surface, which is attributed to energy transported upstream modifying the flow. Average detonation velocities were seen to increase with increasing confiner thickness, while wavefront curvature decreased due to the stiffer, subsonic confinement. Significant radial sidewall tube motion was observed immediately ahead of the detonation. Axial motion was also detected, which interfered with the front shape measurements in some cases. It was concluded that the confiner was able to transport energy ahead of the detonation and that this transport has a definite effect on the detonation by modifying its characteristic shape.

  19. Fuel injector

    DOEpatents

    Lambeth, Malcolm David Dick

    2001-02-27

    A fuel injector comprises first and second housing parts, the first housing part being located within a bore or recess formed in the second housing part, the housing parts defining therebetween an inlet chamber, a delivery chamber axially spaced from the inlet chamber, and a filtration flow path interconnecting the inlet and delivery chambers to remove particulate contaminants from the flow of fuel therebetween.

  20. Equipment specifications for an electrochemical fuel reprocessing plant

    SciTech Connect

    Hemphill, Kevin P

    2010-01-01

    Electrochemical reprocessing is a technique used to chemically separate and dissolve the components of spent nuclear fuel, in order to produce new metal fuel. There are several different variations to electrochemical reprocessing. These variations are accounted for by both the production of different types of spent nuclear fuel, as well as different states and organizations doing research in the field. For this electrochemical reprocessing plant, the spent fuel will be in the metallurgical form, a product of fast breeder reactors, which are used in many nuclear power plants. The equipment line for this process is divided into two main categories, the fuel refining equipment and the fuel fabrication equipment. The fuel refining equipment is responsible for separating out the plutonium and uranium together, while getting rid of the minor transuranic elements and fission products. The fuel fabrication equipment will then convert this plutonium and uranium mixture into readily usable metal fuel.

  1. Storage of H.sub.2 by absorption and/or mixture within a fluid medium

    DOEpatents

    Berry, Gene David; Aceves, Salvador Martin

    2007-03-20

    For the first time, a hydrogen storage method, apparatus and system having a fluid mixture is provided. At predetermined pressures and/or temperatures within a contained substantially fixed volume, the fluid mixture can store a high density of hydrogen molecules, wherein a predetermined phase of the fluid mixture is capable of being withdrawn from the substantially fixed volume for use as a vehicle fuel or energy storage having reduced and/or eliminated evaporative losses, especially where storage weight, vessel cost, vessel shape, safety, and energy efficiency are beneficial.

  2. 40 CFR 86.1309-90 - Exhaust gas sampling system; Otto-cycle and non-petroleum-fueled engines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... gasoline-fueled, natural gas-fueled, liquefied petroleum gas-fueled or methanol-fueled engines. In the CVS... uncharacterized CVS, addition of an unknown inlet restriction on the dilution air, etc.). (2) The gas mixture... allowed. Heating is also allowed, provided: (i) The air (or air plus exhaust gas) temperature does...

  3. Development of Kinetic Mechanisms for Next-Generation Fuels and CFD Simulation of Advanced Combustion Engines

    SciTech Connect

    Pitz, William J.; McNenly, Matt J.; Whitesides, Russell; Mehl, Marco; Killingsworth, Nick J.; Westbrook, Charles K.

    2015-12-17

    Predictive chemical kinetic models are needed to represent next-generation fuel components and their mixtures with conventional gasoline and diesel fuels. These kinetic models will allow the prediction of the effect of alternative fuel blends in CFD simulations of advanced spark-ignition and compression-ignition engines. Enabled by kinetic models, CFD simulations can be used to optimize fuel formulations for advanced combustion engines so that maximum engine efficiency, fossil fuel displacement goals, and low pollutant emission goals can be achieved.

  4. Research fuels local economies

    SciTech Connect

    Bosisio, M. )

    1990-04-01

    Research from US DOA-Agricultural Research Service (ARS) has resulted in a number of new products, alternative crops, and an increase in planted acreage of crops due to pest control by pheromones. Superslurper, produced from cornstarch, was found to absorb 1400 times its weight in moisture. This material is being used in fuel filters to remove water in fuel tanks and pumps. There is a growing market for these filters; superslurpers also are used in body powders, diapers, absorbent soft goods, batteries, soil additives, and in medical and recreational coldpacks. Local economies have benefited as a direct result of ARS efforts.

  5. Fuels from renewable resources

    NASA Astrophysics Data System (ADS)

    Hoffmann, L.; Schnell, C.; Gieseler, G.

    Consideration is given to fuel substitution based on regenerative plants. Methanol can be produced from regenerative plants by gasification followed by the catalytic hydration of carbon oxides. Ethanol can be used as a replacement fuel in gasoline and diesel engines and its high-knock rating allows it to be mixed with lead-free gasoline. Due to the depletion of oil and gas reserves, fermentation alcohol is being considered. The raw materials for the fermentation process can potentially include: (1) sugar (such as yeasts, beet or cane sugar); (2) starch (from potatoes or grain) and (3) cellulose which can be hydrolized into glucose for fermentation.

  6. Turbidimetric Estimation of Alcohol Concentration in Aqueous-Alcohol Mixtures

    ERIC Educational Resources Information Center

    Swinehart, William E.; Zimmerman, Bonnie L.; Powell, Kinsey; Moore, Stephen D.; Iordanov, Tzvetelin D.

    2014-01-01

    A concept of the turbidimetric method for determining the concentration of ethanol in water-ethanol mixtures is described. A closed sample cell containing the analyte was heated to achieve vapor saturation and subsequent condensation. As the condensation occurred, the decrease in percentage transmittance with time due to light scattering was…

  7. STRATEGIES TO IDENTIFY BIOACTIVE SUBSTANCES IN COMPLEX AIR POLLUTANT MIXTURES

    EPA Science Inventory

    Both indoor and outdoor air contains a very complex mixture of gas and particulate matter (PM) pollutants. The assessment of the role of each pollutant in the complex atmosphere in the induction of an associated health effect or a response can be difficult due to many factors, i...

  8. Consolidated fuel reprocessing program: Criticality experiments with fast test reactor fuel pins in an organic moderator

    SciTech Connect

    Bierman, S.R.

    1986-12-01

    The results obtained in a series of criticality experiments performed as part of a joint program on criticality data development between the United States Department of Energy and the Power Reactor and Nuclear Fuel Development Corporation of Japan are presented in this report along with a complete description of the experiments. The experiments involved lattices of Fast Test Reactor (FTR) fuel pins in an organic moderator mixture similar to that used in the solvent extraction stage of fuel reprocessing. The experiments are designed to provide data for direct comparison with previously performed experimental measurements with water moderated lattices of FTR fuel pins. The same lattice arrangements and FTR fuel pin types are used in these organic moderated experimental assemblies as were used in the water moderated experiments. The organic moderator is a mixture of 38 wt % tributylphosphate in a normal paraffin hydrocarbon mixture of C{sub 11}H{sub 24} to C{sub 15}H{sub 32} molecules. Critical sizes of 1054.8, 599.2, 301.8, 199.5 and 165.3 fuel pins were obtained respectively for organic moderated lattices having 0.761 cm, 0.968 cm, 1.242 cm, 1.537 cm and 1.935 cm square lattice pitches as compared to 1046.9, 571.9, 293.9, 199.7 and 165.1 fuel pins for the same lattices water moderated.

  9. Performance and emissions characteristics of a naturally aspirated diesel engine with vegetable oil fuels - 2

    SciTech Connect

    Humke, A.L.; Barsic, N.J.

    1981-01-01

    A naturally aspirated, direct injected diesel engine was used to evaluate the performance and emissions characteristics of a crude soybean oil, a 50 percent (by volume) mixture of crude soybean oil and no. 2 diesel fuel, and a degummed soybean oil. The data were compared with previous tests conducted on the same engine using diesel fuel, crude sunflower oil and a 50 percent mixture of crude sunflower oil and diesel fuel. 18 refs.

  10. Single-element coaxial injector for rocket fuel

    NASA Technical Reports Server (NTRS)

    Larson, L. L.

    1969-01-01

    Improved injector for oxygen difluoride and diborane has better mixing characteristics and is able to project fuel onto the wall of the combustion chamber for better cooling. It produces an essentially conical, diverging, continuous sheet of propellant mixture formed by similarly shaped and continuously impinging sheets of fuel and oxidant.

  11. EVALUATION OF CARBON BLACK SLURRIES AS CLEAN BURNING FUELS

    EPA Science Inventory

    Experiments were performed to examine the pumpability, atomization and combustion characteristics of slurries made of mixtures of carbon black with No. 2 fuel oil and methanol. Carbon black-No. 2 fuel oil and carbon black-methanol slurries, with carbon black contents of up to 50 ...

  12. Highly selective condensation of biomass-derived methyl ketones as a source of aviation fuel.

    PubMed

    Sacia, Eric R; Balakrishnan, Madhesan; Deaner, Matthew H; Goulas, Konstantinos A; Toste, F Dean; Bell, Alexis T

    2015-05-22

    Aviation fuel (i.e., jet fuel) requires a mixture of C9 -C16 hydrocarbons having both a high energy density and a low freezing point. While jet fuel is currently produced from petroleum, increasing concern with the release of CO2 into the atmosphere from the combustion of petroleum-based fuels has led to policy changes mandating the inclusion of biomass-based fuels into the fuel pool. Here we report a novel way to produce a mixture of branched cyclohexane derivatives in very high yield (>94 %) that match or exceed many required properties of jet fuel. As starting materials, we use a mixture of n-alkyl methyl ketones and their derivatives obtained from biomass. These synthons are condensed into trimers via base-catalyzed aldol condensation and Michael addition. Hydrodeoxygenation of these products yields mixtures of C12 -C21 branched, cyclic alkanes. Using models for predicting the carbon number distribution obtained from a mixture of n-alkyl methyl ketones and for predicting the boiling point distribution of the final mixture of cyclic alkanes, we show that it is possible to define the mixture of synthons that will closely reproduce the distillation curve of traditional jet fuel.

  13. Odour suppression in binary mixtures.

    PubMed

    Cashion, Larry; Livermore, Andrew; Hummel, Thomas

    2006-10-01

    It has been suggested that odours causing stronger trigeminal activation suppress weaker trigeminal stimuli and that mixed olfactory-trigeminal stimuli suppress odorants that only activate one of these systems. Volunteer normosmic participants (n=20) were exposed to six odorants with varying trigeminal impact to test the hypothesis that more intense "trigeminal" odorants would suppress weaker trigeminal stimuli in binary odour mixtures. It was also hypothesised that stronger trigeminal odorants would dominate six-odour mixtures. The predicted linear pattern of suppression was not seen, with a quadratic model emerging from the data. Stronger trigeminal stimuli failed to dominate six-odour mixtures. Despite the fact that the major hypothesis was not supported, it can be hypothesised from this experiment that the effect of suppression in binary mixtures is reliant upon two major effects: (1) the association formed between odours and the multiple memory systems that they interact with during the encoding and recognition processes, and (2) the balance between activation of the olfactory and trigeminal systems.

  14. Thermal performance of Al2O3 in water - ethylene glycol nanofluid mixture as cooling medium in mini channel

    NASA Astrophysics Data System (ADS)

    Zakaria, Irnie Azlin; Mohamed, Wan Ahmad Najmi Wan; Mamat, Aman Mohd Ihsan; Sainan, Khairul Imran; Talib, Siti Fatimah Abu

    2015-08-01

    Continuous need for an optimum conversion efficiency of a Proton Exchange Membrane Fuel Cell (PEMFC) operation has triggered varieties of advancements namely on the thermal management engineering scope. Nanofluids as an innovative heat transfer fluid solution are expected to be a promising candidate for alternative coolant in mini channel cooling plate of PEMFC. In this work, heat transfer performance of low concentration of 0.1, 0.3 and 0.5 % Al2O3 in water: Ethylene glycol (EG) mixtures of 100:0 and 50:50 nanofluids have been studied and compared against its base fluids at Re number ranging from 10 to 100. A steady, laminar and incompressible flow with constant heat flux is assumed in the channel of 140mm × 200mm. It was found that nanofluids have performed better than the base fluid but the demerit is on the pumping power due to the higher pressure drop across mini channel geometry as expected.

  15. Heterogeneous fuel for hybrid rocket

    NASA Technical Reports Server (NTRS)

    Stickler, David B. (Inventor)

    1996-01-01

    Heterogeneous fuel compositions suitable for use in hybrid rocket engines and solid-fuel ramjet engines, The compositions include mixtures of a continuous phase, which forms a solid matrix, and a dispersed phase permanently distributed therein. The dispersed phase or the matrix vaporizes (or melts) and disperses into the gas flow much more rapidly than the other, creating depressions, voids and bumps within and on the surface of the remaining bulk material that continuously roughen its surface, This effect substantially enhances heat transfer from the combusting gas flow to the fuel surface, producing a correspondingly high burning rate, The dispersed phase may include solid particles, entrained liquid droplets, or gas-phase voids having dimensions roughly similar to the displacement scale height of the gas-flow boundary layer generated during combustion.

  16. Evaluation of the genetic toxicity of middle distillate fuels.

    PubMed

    McKee, R H; Amoruso, M A; Freeman, J J; Przygoda, R T

    1994-01-01

    Petroleum middle distillate (PMD) fuels are mixtures of hydrocarbons that distill between approximately 170-370 degrees C. Commercial products that fall into this category include kerosine, diesel fuel, jet fuel, and home heating oil. These products contain both saturated (paraffins and cycloparaffins) and aromatic species, but because of the boiling range normally contain very small amounts of the 3-6 ring polycyclic aromatic hydrocarbon (PAH) constituents, which are considered to be carcinogenic. Nevertheless, there is evidence of weak tumorigenic activity when these materials are repeatedly applied to mouse skin. In the current studies representative products were tested in two commonly used, short-term assays for genetic toxicity, the Salmonella/mammalian microsome mutagenicity assay and the mouse bone marrow micronucleus test. All samples were inactive in the micronucleus assay, and three were clearly inactive in the Salmonella test. Of the remaining two, one was marginally active in the Salmonella assay, and one was equivocal. The marginally active sample contained detectable levels of PAH due to the use of catalytically cracked materials as blending stocks. The results indicated that PMDs that do not contain cracked material were not mutagenic. Thus they may produce tumors via nongenotoxic processes. Those products that do contain cracked stocks may have sufficient PAH to be mutagenic in the Salmonella assay, and in those cases the PAH might also contribute to tumor formation.

  17. Downhole steam generator using low pressure fuel and air supply

    DOEpatents

    Fox, Ronald L.

    1983-01-01

    An apparatus for generation of steam in a borehole for penetration into an earth formation wherein a spiral, tubular heat exchanger is used in the combustion chamber to isolate the combustion process from the water being superheated for conversion into steam. The isolation allows combustion of a relatively low pressure oxidant and fuel mixture for generating high enthalpy steam. The fuel is preheated by feedback of combustion gases from the top of the combustion chamber through a fuel preheater chamber. The hot exhaust gases of combustion at the bottom of the combustion chamber, after flowing over the heat exchanger enter an exhaust passage and pipe. The exhaust pipe is mounted inside the water supply line heating the water flowing into the heat exchanger. After being superheated in the heat exchanger, the water is ejected through an expansion nozzle and converts into steam prior to penetration into the earth formation. Pressure responsive doors are provided at a steam outlet downstream of the nozzle and close when the steam pressure is lost due to flameout.

  18. Direct numerical simulation of ignition in turbulent n-heptane liquid-fuel spray jets

    SciTech Connect

    Wang, Y.; Rutland, C.J.

    2007-06-15

    Direct numerical simulation was used for fundamental studies of the ignition of turbulent n-heptane liquid-fuel spray jets. A chemistry mechanism with 33 species and 64 reactions was adopted to describe the chemical reactions. The Eulerian method is employed to solve the carrier-gas flow field and the Lagrangian method is used to track the liquid-fuel droplets. Two-way coupling interaction is considered through the exchange of mass, momentum, and energy between the carrier-gas fluid and the liquid-fuel spray. The initial carrier-gas temperature was 1500 K. Six cases were simulated with different droplet radii (from 10 to 30 {mu}m) and two initial velocities (100 and 150 m/s). From the simulations, it was found that evaporative cooling and turbulence mixing play important roles in the ignition of liquid-fuel spray jets. Ignition first occurs at the edges of the jets where the fuel mixture is lean, and the scalar dissipation rate and the vorticity magnitude are very low. For smaller droplets, ignition occurs later than for larger droplets due to increased evaporative cooling. Higher initial droplet velocity enhances turbulence mixing and evaporative cooling. For smaller droplets, higher initial droplet velocity causes the ignition to occur earlier, whereas for larger droplets, higher initial droplet velocity delays the ignition time. (author)

  19. Abundance of (14)C in biomass fractions of wastes and solid recovered fuels.

    PubMed

    Fellner, Johann; Rechberger, Helmut

    2009-05-01

    In recent years thermal utilization of mixed wastes and solid recovered fuels has become of increasing importance in European waste management. Since wastes or solid recovered fuels are generally composed of fossil and biogenic materials, only part of the CO(2) emissions is accounted for in greenhouse gas inventories or emission trading schemes. A promising approach for determining this fraction is the so-called radiocarbon method. It is based on different ratios of the carbon isotopes (14)C and (12)C in fossil and biogenic fuels. Fossil fuels have zero radiocarbon, whereas biogenic materials are enriched in (14)C and reflect the (14)CO(2) abundance of the ambient atmosphere. Due to nuclear weapons tests in the past century, the radiocarbon content in the atmosphere has not been constant, which has resulted in a varying (14)C content of biogenic matter, depending on the period of growth. In the present paper (14)C contents of different biogenic waste fractions (e.g., kitchen waste, paper, wood), as well as mixtures of different wastes (household, bulky waste, and commercial waste), and solid recovered fuels are determined. The calculated (14)C content of the materials investigated ranges between 98 and 135pMC.

  20. Abundance of (14)C in biomass fractions of wastes and solid recovered fuels.

    PubMed

    Fellner, Johann; Rechberger, Helmut

    2009-05-01

    In recent years thermal utilization of mixed wastes and solid recovered fuels has become of increasing importance in European waste management. Since wastes or solid recovered fuels are generally composed of fossil and biogenic materials, only part of the CO(2) emissions is accounted for in greenhouse gas inventories or emission trading schemes. A promising approach for determining this fraction is the so-called radiocarbon method. It is based on different ratios of the carbon isotopes (14)C and (12)C in fossil and biogenic fuels. Fossil fuels have zero radiocarbon, whereas biogenic materials are enriched in (14)C and reflect the (14)CO(2) abundance of the ambient atmosphere. Due to nuclear weapons tests in the past century, the radiocarbon content in the atmosphere has not been constant, which has resulted in a varying (14)C content of biogenic matter, depending on the period of growth. In the present paper (14)C contents of different biogenic waste fractions (e.g., kitchen waste, paper, wood), as well as mixtures of different wastes (household, bulky waste, and commercial waste), and solid recovered fuels are determined. The calculated (14)C content of the materials investigated ranges between 98 and 135pMC. PMID:19157836

  1. Abundance of {sup 14}C in biomass fractions of wastes and solid recovered fuels

    SciTech Connect

    Fellner, Johann Rechberger, Helmut

    2009-05-15

    In recent years thermal utilization of mixed wastes and solid recovered fuels has become of increasing importance in European waste management. Since wastes or solid recovered fuels are generally composed of fossil and biogenic materials, only part of the CO{sub 2} emissions is accounted for in greenhouse gas inventories or emission trading schemes. A promising approach for determining this fraction is the so-called radiocarbon method. It is based on different ratios of the carbon isotopes {sup 14}C and {sup 12}C in fossil and biogenic fuels. Fossil fuels have zero radiocarbon, whereas biogenic materials are enriched in {sup 14}C and reflect the {sup 14}CO{sub 2} abundance of the ambient atmosphere. Due to nuclear weapons tests in the past century, the radiocarbon content in the atmosphere has not been constant, which has resulted in a varying {sup 14}C content of biogenic matter, depending on the period of growth. In the present paper {sup 14}C contents of different biogenic waste fractions (e.g., kitchen waste, paper, wood), as well as mixtures of different wastes (household, bulky waste, and commercial waste), and solid recovered fuels are determined. The calculated {sup 14}C content of the materials investigated ranges between 98 and 135 pMC.

  2. Fuel cell-fuel cell hybrid system

    DOEpatents

    Geisbrecht, Rodney A.; Williams, Mark C.

    2003-09-23

    A device for converting chemical energy to electricity is provided, the device comprising a high temperature fuel cell with the ability for partially oxidizing and completely reforming fuel, and a low temperature fuel cell juxtaposed to said high temperature fuel cell so as to utilize remaining reformed fuel from the high temperature fuel cell. Also provided is a method for producing electricity comprising directing fuel to a first fuel cell, completely oxidizing a first portion of the fuel and partially oxidizing a second portion of the fuel, directing the second fuel portion to a second fuel cell, allowing the first fuel cell to utilize the first portion of the fuel to produce electricity; and allowing the second fuel cell to utilize the second portion of the fuel to produce electricity.

  3. Uphill diffusion in multicomponent mixtures.

    PubMed

    Krishna, Rajamani

    2015-05-21

    Molecular diffusion is an omnipresent phenomena that is important in a wide variety of contexts in chemical, physical, and biological processes. In the majority of cases, the diffusion process can be adequately described by Fick's law that postulates a linear relationship between the flux of any species and its own concentration gradient. Most commonly, a component diffuses down the concentration gradient. The major objective of this review is to highlight a very wide variety of situations that cause the uphill transport of one constituent in the mixture. Uphill diffusion may occur in multicomponent mixtures in which the diffusion flux of any species is strongly coupled to that of its partner species. Such coupling effects often arise from strong thermodynamic non-idealities. For a quantitative description we need to use chemical potential gradients as driving forces. The transport of ionic species in aqueous solutions is coupled with its partner ions because of the electro-neutrality constraints; such constraints may accelerate or decelerate a specific ion. When uphill diffusion occurs, we observe transient overshoots during equilibration; the equilibration process follows serpentine trajectories in composition space. For mixtures of liquids, alloys, ceramics and glasses the serpentine trajectories could cause entry into meta-stable composition zones; such entry could result in phenomena such as spinodal decomposition, spontaneous emulsification, and the Ouzo effect. For distillation of multicomponent mixtures that form azeotropes, uphill diffusion may allow crossing of distillation boundaries that are normally forbidden. For mixture separations with microporous adsorbents, uphill diffusion can cause supra-equilibrium loadings to be achieved during transient uptake within crystals; this allows the possibility of over-riding adsorption equilibrium for achieving difficult separations.

  4. Uphill diffusion in multicomponent mixtures.

    PubMed

    Krishna, Rajamani

    2015-05-21

    Molecular diffusion is an omnipresent phenomena that is important in a wide variety of contexts in chemical, physical, and biological processes. In the majority of cases, the diffusion process can be adequately described by Fick's law that postulates a linear relationship between the flux of any species and its own concentration gradient. Most commonly, a component diffuses down the concentration gradient. The major objective of this review is to highlight a very wide variety of situations that cause the uphill transport of one constituent in the mixture. Uphill diffusion may occur in multicomponent mixtures in which the diffusion flux of any species is strongly coupled to that of its partner species. Such coupling effects often arise from strong thermodynamic non-idealities. For a quantitative description we need to use chemical potential gradients as driving forces. The transport of ionic species in aqueous solutions is coupled with its partner ions because of the electro-neutrality constraints; such constraints may accelerate or decelerate a specific ion. When uphill diffusion occurs, we observe transient overshoots during equilibration; the equilibration process follows serpentine trajectories in composition space. For mixtures of liquids, alloys, ceramics and glasses the serpentine trajectories could cause entry into meta-stable composition zones; such entry could result in phenomena such as spinodal decomposition, spontaneous emulsification, and the Ouzo effect. For distillation of multicomponent mixtures that form azeotropes, uphill diffusion may allow crossing of distillation boundaries that are normally forbidden. For mixture separations with microporous adsorbents, uphill diffusion can cause supra-equilibrium loadings to be achieved during transient uptake within crystals; this allows the possibility of over-riding adsorption equilibrium for achieving difficult separations. PMID:25761383

  5. Alternative Aviation Fuel Experiment (AAFEX)

    NASA Technical Reports Server (NTRS)

    Anderson, B. E.; Beyersdorf, A. J.; Hudgins, C. H.; Plant, J. V.; Thornhill, K. L.; Winstead, E. L.; Ziemba, L. D.; Howard, R.; Corporan, E.; Miake-Lye, R. C.; Herndon, S. C.; Timko, M.; Woods, E.; Dodds, W.; Lee, B.; Santoni, G.; Whitefield, P.; Hagen, D.; Lobo, P.; Knighton, W. B.; Bulzan, D.; Tacina, K.; Wey, C.; VanderWal, R.; Bhargava, A.

    2011-01-01

    The rising cost of oil coupled with the need to reduce pollution and dependence on foreign suppliers has spurred great interest and activity in developing alternative aviation fuels. Although a variety of fuels have been produced that have similar properties to standard Jet A, detailed studies are required to ascertain the exact impacts of the fuels on engine operation and exhaust composition. In response to this need, NASA acquired and burned a variety of alternative aviation fuel mixtures in the Dryden Flight Research Center DC-8 to assess changes in the aircraft s CFM-56 engine performance and emission parameters relative to operation with standard JP-8. This Alternative Aviation Fuel Experiment, or AAFEX, was conducted at NASA Dryden s Aircraft Operations Facility (DAOF) in Palmdale, California, from January 19 to February 3, 2009 and specifically sought to establish fuel matrix effects on: 1) engine and exhaust gas temperatures and compressor speeds; 2) engine and auxiliary power unit (APU) gas phase and particle emissions and characteristics; and 3) volatile aerosol formation in aging exhaust plumes

  6. Antimisting fuel breakup and flammability

    NASA Technical Reports Server (NTRS)

    Parikh, P.; Fleeter, R.; Sarohia, V.

    1983-01-01

    The breakup behavior and flammability of antimisting turbine fuels subjected to aerodynamic shear are investigated. Fuels tested were Jet A containing 0.3% FM-9 polymer at various levels of degradation ranging from virgin AMK to neat Jet A. The misting behavior of the fuels was quantified by droplet size distribution measurements. A technique based on high resolution laser photography and digital image processing of photographic records for rapid determination of droplet size distribution was developed. The flammability of flowing droplet-air mixtures was quantified by direct measurements of temperature rise in a flame established in the wake of a continuous ignition source. The temperature rise measurements were correlated with droplet size measurements. The flame anchoring phenomenon associated with the breakup of a liquid fuel in the wake of bluff body was shown to be important in the context of a survivable crash scenario. A pass/fail criterion for flammability testing of antimisting fuels, based on this flame-anchoring phenomenon, was proposed. The role of various ignition sources and their intensity in ignition and post-ignition behavior of antimisting fuels was also investigated.

  7. Fuel Flexible, Low Emission Catalytic Combustor for Opportunity Fuel Applications

    SciTech Connect

    Eteman, Shahrokh

    2013-06-30

    Limited fuel resources, increasing energy demand and stringent emission regulations are drivers to evaluate process off-gases or process waste streams as fuels for power generation. Often these process waste streams have low energy content and/or highly reactive components. Operability of low energy content fuels in gas turbines leads to issues such as unstable and incomplete combustion. On the other hand, fuels containing higher-order hydrocarbons lead to flashback and auto-ignition issues. Due to above reasons, these fuels cannot be used directly without modifications or efficiency penalties in gas turbine engines. To enable the use of these wide variety of fuels in gas turbine engines a rich catalytic lean burn (RCL®) combustion system was developed and tested in a subscale high pressure (10 atm.) rig. The RCL® injector provided stability and extended turndown to low Btu fuels due to catalytic pre-reaction. Previous work has shown promise with fuels such as blast furnace gas (BFG) with LHV of 85 Btu/ft3 successfully combusted. This program extends on this work by further modifying the combustor to achieve greater catalytic stability enhancement. Fuels containing low energy content such as weak natural gas with a Lower Heating Value (LHV) of 6.5 MJ/m3 (180 Btu/ft3 to natural gas fuels containing higher hydrocarbon (e.g ethane) with LHV of 37.6 MJ/m3 (1010 Btu/ft3) were demonstrated with improved combustion stability; an extended turndown (defined as the difference between catalytic and non-catalytic lean blow out) of greater than 250oF was achieved with CO and NOx emissions lower than 5 ppm corrected to 15% O2. In addition, for highly reactive fuels the catalytic region preferentially pre-reacted the higher order hydrocarbons with no events of flashback or auto-ignition allowing a stable and safe operation with low NOx and CO emissions.

  8. Experimental verification of the thermodynamic properties for a jet-A fuel

    NASA Technical Reports Server (NTRS)

    Graciasalcedo, Carmen M.; Brabbs, Theodore A.; Mcbride, Bonnie J.

    1988-01-01

    Thermodynamic properties for a Jet-A fuel were determined by Shell Development Company in 1970 under a contract for NASA Lewis Research Center. The polynomial fit necessary to include Jet-A fuel (liquid and gaseous phases) in the library of thermodynamic properties of the NASA Lewis Chemical Equilibrium Program is calculated. To verify the thermodynamic data, the temperatures of mixtures of liquid Jet-A injected into a hot nitrogen stream were experimentally measured and compared to those calculated by the program. Iso-octane, a fuel for which the thermodynamic properties are well known, was used as a standard to calibrate the apparatus. The measured temperatures for the iso-octane/nitrogen mixtures reproduced the calculated temperatures except for a small loss due to the non-adiabatic behavior of the apparatus. The measurements for Jet-A were corrected for this heat loss and showed excellent agreement with the calculated temperatures. These experiments show that this process can be adequately described by the thermodynamic properties fitted for the Chemical Equilibrium Program.

  9. Effect of the NACA Injection Impeller on the Mixture Distribution of a Double-row Radial Aircraft Engine

    NASA Technical Reports Server (NTRS)

    Marble, Frank E.; Ritter, William K.; Miller, Mahlon A.

    1946-01-01

    For the normal range of engine power the impeller provided marked improvement over the standard spray-bar injection system. Mixture distribution at cruising was excellent, maximum cylinder temperatures were reduced about 30 degrees F, and general temperature distribution was improved. The uniform mixture distribution restored the normal response of cylinder temperature to mixture enrichment and it reduced the possibility of carburetor icing, while no serious loss in supercharger pressure rise resulted from injection of fuel near the impeller outlet. The injection impeller also furnished a convenient means of adding water to the charge mixture for internal cooling.

  10. Swedish tests on rape-seed oil as an alternative to diesel fuel

    SciTech Connect

    Johansson, E.; Nordstroem, O.

    1982-01-01

    The cheapest version of Swedish rape-seed oil was chosen. First the rape-seed oil was mixed in different proportions with regular diesel fuel. A mixture of 1/3 rape-seed oil and 2/3 regular diesel fuel (R 33) was then selected for a long-term test. A Perkins 4.248 diesel engine was used for laboratory tests. Four regular farm tractors, owned and operated by farmers, and two tractors belonging to the Institute have been running on R 33. Each tractor was calibrated on a dynamometer according to Swedish and ISO-standards before they were operated on R 33. Since then the tractors have been regularly recalibrated. The test tractors have been operated on R 33 for more than 3400 h. An additional 1200 h have been covered by the laboratory test engine. None of the test tractors have hitherto required repairs due to the use of R 33, but some fuel filters have been replaced. Some fuel injectors have been cleaned due to deposits on the nozzles. 4 figures, 1 table.

  11. Effects of Fuel Distribution on Detonation Tube Performance

    NASA Technical Reports Server (NTRS)

    Perkins, Hugh Douglas

    2002-01-01

    A pulse detonation engine (PDE) uses a series of high frequency intermittent detonation tubes to generate thrust. The process of filling the detonation tube with fuel and air for each cycle may yield non-uniform mixtures. Lack of mixture uniformity is commonly ignored when calculating detonation tube thrust performance. In this study, detonation cycles featuring idealized non-uniform H2/air mixtures were analyzed using the SPARK two-dimensional Navier-Stokes CFD code with 7-step H2/air reaction mechanism. Mixture non-uniformities examined included axial equivalence ratio gradients, transverse equivalence ratio gradients, and partially fueled tubes. Three different average test section equivalence ratios (phi), stoichiometric (phi = 1.00), fuel lean (phi = 0.90), and fuel rich (phi = 1.10), were studied. All mixtures were detonable throughout the detonation tube. It was found that various mixtures representing the same test section equivalence ratio had specific impulses within 1 percent of each other, indicating that good fuel/air mixing is not a prerequisite for optimal detonation tube performance.

  12. Study of the combustion of various alternate fuels

    SciTech Connect

    Barfield, B.F.; Acker, G.J. Jr.; Lindsay, M.H.

    1984-01-01

    This research project used two methods for studying the problems facing alternate fuels. The first method studied the use of chemicals to improve fuel characteristics without changing the basic engine design. The second method was to make engine modifications to suit characteristics of the alternate fuel. The result of the two methods studied is a two-part report. Alcohols, solvent-refined coal (SRC-II), vegetable oils, and mixtures of these with diesel fuels and with each other are the alternative fuels discussed and tested. 21 references, 4 figures, 10 tables.

  13. Ceramic fuel pellets for isotopic heat sources

    SciTech Connect

    Rankin, D.T.; Congdon, J.W.; Livingston, J.T.; Duncan, N.D.

    1980-01-01

    The General-Purpose Heat Source (GPHS) will supply power for future space missions. The GPHS fuel pellets are fabricated by hot pressing a blended mixture of /sup 238/PuO/sub 2/ granules prepared from calcined plutonium oxalate. Results of a test program which led to the development of the production process are described.

  14. Fuel Flexibility in Gasification

    SciTech Connect

    McLendon, T. Robert; Pineault, Richard L.; Richardson, Steven W.; Rockey, John M.; Beer, Stephen K.; Lui, Alain P.; Batton, William A.

    2001-11-06

    In order to increase efficiencies of carbonizers, operation at high pressures is needed. In addition, waste biomass fuels of opportunity can be used to offset fossil fuel use. The National Energy Technology Laboratory (NETL) Fluidized Bed Gasifier/Combustor (FBG/C) was used to gasify coal and mixtures of coal and biomass (sawdust) at 425 psig. The purpose of the testing program was to generate steady state operating data for modeling efforts of carbonizers. A test program was completed with a matrix of parameters varied one at a time in order to avoid second order interactions. Variables were: coal feed rate, pressure, and varying mixtures of sawdust and coal types. Coal types were Montana Rosebud subbituminous and Pittsburgh No. 8 bituminous. The sawdust was sanding waste from a furniture manufacturer in upstate New York. Coal was sieved from -14 to +60 mesh and sawdust was sieved to -14 mesh. The FBG/C operates at a nominal 425 psig, but pressures can be lowered. For the tests reported it was operated as a jetting, fluidized bed, ash-agglomerating gasifier. Preheated air and steam are injected into the center of the bottom along with the solid feed that is conveyed with cool air. Fairly stable reactor internal flow patterns develop and temperatures stabilize (with some fluctuations) when steady state is reached. At nominal conditions the solids residence time in the reactor is on the order of 1.5 to 2 hours, so changes in feed types can require on the order of hours to equilibrate. Changes in operating conditions (e.g. feed rate) usually require much less time. The operating periods of interest for these tests were only the steady state periods, so transient conditions were not monitored as closely. The test matrix first established a base case of operations to which single parameter changes in conditions could be compared. The base case used Montana Rosebud at a coal feed rate of 70 lbm/hr at 425 psig. The coal sawdust mixtures are reported as percent by weight

  15. Determination, correlation, and mechanistic interpretation of effects of hydrogen addition on laminar flame speeds of hydrocarbon–air mixtures

    SciTech Connect

    Tang, C. L.; Huang, Z. H.; Law, C. K.

    2010-08-30

    The stretch-affected propagation speeds of expanding spherical flames of n-butane–air mixtures with hydrogen addition were measured at atmospheric pressure and subsequently processed through a nonlinear regression analysis to yield the stretch-free laminar flame speeds. Based on a hydrogen addition parameter (RH) and an effective fuel equivalence ratio (ΦF), these laminar flame speeds were found to increase almost linearly with RH, for ΦF between 0.6 and 1.4 and RHRH from 0 to 0.5, with the slope of the variation assuming a minimum around stoichiometry. These experimental results also agree well with computed values using a detailed reaction mechanism. Furthermore, a mechanistic investigation aided by sensitivity analysis identified that kinetic effects through the global activation energy, followed by thermal effects through the adiabatic flame temperature, have the most influence on the increase in the flame speeds and the associated linear variation with RH due to hydrogen addition. Nonequidiffusion effects due to the high mobility of hydrogen, through the global Lewis number, have the least influence. Further calculations for methane, ethene, and propane as the fuel showed similar behavior, leading to possible generalization of the phenomena and correlation.

  16. FUEL ELEMENT

    DOEpatents

    Bean, R.W.

    1963-11-19

    A ceramic fuel element for a nuclear reactor that has improved structural stability as well as improved cooling and fission product retention characteristics is presented. The fuel element includes a plurality of stacked hollow ceramic moderator blocks arranged along a tubular raetallic shroud that encloses a series of axially apertured moderator cylinders spaced inwardly of the shroud. A plurality of ceramic nuclear fuel rods are arranged in the annular space between the shroud and cylinders of moderator and appropriate support means and means for directing gas coolant through the annular space are also provided. (AEC)

  17. Fuel ethanol

    SciTech Connect

    Not Available

    1989-02-01

    This report discusses the Omnibus Trade and Competitiveness Act of 1988 which requires GAO to examine fuel ethanol imports from Central America and the Caribbean and their impact on the U.S. fuel ethanol industry. Ethanol is the alcohol in beverages, such as beer, wine, and whiskey. It can also be used as a fuel by blending with gasoline. It can be made from renewable resources, such as corn, wheat, grapes, and sugarcane, through a process of fermentation. This report finds that, given current sugar and gasoline prices, it is not economically feasible for Caribbean ethanol producers to meet the current local feedstock requirement.

  18. Raman and XPS characterization of fuel cladding interactions using miniature specimens

    NASA Astrophysics Data System (ADS)

    Windisch, C. F., Jr.; Henager, C. H., Jr.; Engelhard, M. H.; Bennett, W. D.

    2009-01-01

    A combination of laser Raman spectroscopy and X-ray photoelectron spectroscopy was applied in a study of fuel-cladding chemical interactions on miniature oxide-coated HT-9 disks at elevated temperature. The experiments were intended as a preliminary step toward the development of a quick-screening technique for candidate alloys for cladding materials and actinide-based mixed oxide fuel mixtures. The results indicated that laser Raman spectroscopy was capable of determining the major oxides on HT-9 and how they changed in composition due to heating. However, X-ray photoelectron spectroscopy was necessary to identify the role of the metallic phases and provide depth resolution. Using the two techniques the kinetics of chromia growth were shown to be affected by the presence of an applied oxide coating. A single replacement reaction involving residual reduced metal within the coating was also identified.

  19. Evaluation of nickel-titanium oxide-niobium pentoxide metal ceramic composite as interconnect for solid oxide fuel cell

    NASA Astrophysics Data System (ADS)

    Budur, Abhijith

    With increasing importance for clean energy, fuel cells have gained great significance in recent decades. Solid oxide fuel cells are easy to transport due to presence of solid electrolyte and also have requisite electrical properties,but have been obstructed by their limitation to be used at only temperatures greater than 6000C and less than 8000C. To construct a stack of cells, materials that are good electrical conductors and having necessary mechanical strengths at that temperatures are being considered as interconnects between the cells. Evaluation of Nickel-Titanium dioxide-Niobium pentoxide (NTN) as interconnect and comparison to Stainless Steel 441 alloy has been made in this research. The criteria for evaluation are the resistance, long-term stability and the power density characteristics of the cell for each interconnect. Electrical measurements by impedance spectroscopy techniques were conducted at variousworking temperatures using a gas mixture of 10 % hydrogen and 90% nitrogen to evaluate both interconnect materials in the working range of fuel cells. Scanning Electron Microscopy images of Lanthanum Strontium Manganite paste before and after the fuel cell measurements are shown.The results showed that both NTN and Stainless Steel 441 interconnects exhibit similar electrical properties under operating conditions of the fuel cell. Since theNTN interconnect is less prone to corrosion and does not have the effect of chromium poisoning, it can be considered as a viable interconnect material for solid oxide fuel cells.

  20. 40 CFR 1065.701 - General requirements for test fuels.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... parameters in 40 CFR 80.46. (e) Two-stroke fuel/oil mixing. For two-stroke engines, use a fuel/oil mixture.... Gas turbine ASTM D1655-07e01. Jet B wide cut ASTM D6615-06. Gas turbine fuel General ASTM D2880-03l... 40 Protection of Environment 34 2013-07-01 2013-07-01 false General requirements for test...