Holographic studies of the vapor explosion of vaporizing water-in-fuel emulsion droplets

NASA Technical Reports Server (NTRS)

Sheffield, S. A.; Hess, C. F.; Trolinger, J. D.

1982-01-01

Holographic studies were performed which examined the fragmentation process during vapor explosion of a water-in-fuel (hexadecane/water) emulsion droplet. Holograms were taken at 700 to 1000 microseconds after the vapor explosion. Photographs of the reconstructed holograms reveal a wide range of fragment droplet sizes created during the explosion process. Fragment droplet diameters range from below 10 microns to over 100 microns. It is estimated that between ten thousand and a million fragment droplets can result from this extremely violent vapor explosion process. This enhanced atomization is thus expected to have a pronounced effect on vaporization processes which are present during combustion of emulsified fuels.

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.

Computational Thermodynamics Analysis of Vaporizing Fuel Droplets in the Human Upper Airways

NASA Astrophysics Data System (ADS)

Zhang, Zhe; Kleinstreuer, Clement

The detailed knowledge of air flow structures as well as particle transport and deposition in the human lung for typical inhalation flow rates is an important precursor for dosimetry-and-health-effect studies of toxic particles as well as for targeted drug delivery of therapeutic aerosols. Focusing on highly toxic JP-8 fuel aerosols, 3-D airflow and fluid-particle thermodynamics in a human upper airway model starting from mouth to Generation G3 (G0 is the trachea) are simulated using a user-enhanced and experimentally validated finite-volume code. The temperature distributions and their effects on airflow structures, fuel vapor deposition and droplet motion/evaporation are discussed. The computational results show that the thermal effect on vapor deposition is minor, but it may greatly affect droplet deposition in human airways.

Effect of fuel vapor concentrations on combustor emissions and performance

NASA Technical Reports Server (NTRS)

Norgren, C. T.; Ingebo, R. D.

1973-01-01

Effects of fuel vaporization on the exhaust emission levels of oxides of nitrogen, carbon monoxide, total hydrocarbons, and smoke number were obtained in an experimental turbojet combustor segment. Two different fuel injectors were used in which liquid ASTM A-1 jet fuel and vapor propane fuel were independently controlled to simulate varying degrees of vaporization. Tests were conducted over a range of inlet-air temperatures from 478 to 700 K, pressures from 4 to 20 atm, and combustor reference velocities from 15.3 to 27.4 m/sec. Converting from liquid to complete vapor fuel resulted in oxides of nitrogen reductions of as much as 22 percent and smoke number reductions up to 51 percent. Supplement data are also presented on flame emissivity, flame temperature, and primary-zone liner wall temperatures.

Vapor-fed bio-hybrid fuel cell.

PubMed

Benyamin, Marcus S; Jahnke, Justin P; Mackie, David M

2017-01-01

Concentration and purification of ethanol and other biofuels from fermentations are energy-intensive processes, with amplified costs at smaller scales. To circumvent the need for these processes, and to potentially reduce transportation costs as well, we have previously investigated bio-hybrid fuel cells (FCs), in which a fermentation and FC are closely coupled. However, long-term operation requires strictly preventing the fermentation and FC from harming each other. We introduce here the concept of the vapor-fed bio-hybrid FC as a means of continuously extracting power from ongoing fermentations at ambient conditions. By bubbling a carrier gas (N 2 ) through a yeast fermentation and then through a direct ethanol FC, we protect the FC anode from the catalyst poisons in the fermentation (which are non-volatile), and also protect the yeast from harmful FC products (notably acetic acid) and from build-up of ethanol. Since vapor-fed direct ethanol FCs at ambient conditions have never been systematically characterized (in contrast to vapor-fed direct methanol FCs), we first assess the effects on output power and conversion efficiency of ethanol concentration, vapor flow rate, and FC voltage. The results fit a continuous stirred-tank reactor model. Over a wide range of ethanol partial pressures (2-8 mmHg), power densities are comparable to those for liquid-fed direct ethanol FCs at the same temperature, with power densities >2 mW/cm 2 obtained. We then demonstrate the continuous operation of a vapor-fed bio-hybrid FC with fermentation for 5 months, with no indication of performance degradation due to poisoning (of either the FC or the fermentation). It is further shown that the system is stable, recovering quickly from disturbances or from interruptions in maintenance. The vapor-fed bio-hybrid FC enables extraction of power from dilute bio-ethanol streams without costly concentration and purification steps. The concept should be scalable to both large and small

Vapor transport mechanisms

NASA Technical Reports Server (NTRS)

Workman, G. L.

1978-01-01

The Raman scattering furnace for investigating vapor transport mechanisms was completed and checked out. Preliminary experiments demonstate that a temperature resolution of plus and minus 5 C is possible with this system operating in a backscatter mode. In the experiments presented with the GeI 4 plus excess Ge system at temperatures up to 600 C, only the GeI4 band at 150 cm superscript minus 1 was observed. Further experiments are in progress to determine if GeI2 does become the major vapor species above 440 C.

Mid-infrared laser-absorption diagnostic for vapor-phase fuel mole fraction and liquid fuel film thickness

NASA Astrophysics Data System (ADS)

Porter, J. M.; Jeffries, J. B.; Hanson, R. K.

2011-02-01

A novel two-wavelength mid-infrared laser-absorption diagnostic has been developed for simultaneous measurements of vapor-phase fuel mole fraction and liquid fuel film thickness. The diagnostic was demonstrated for time-resolved measurements of n-dodecane liquid films in the absence and presence of n-decane vapor at 25°C and 1 atm. Laser wavelengths were selected from FTIR measurements of the C-H stretching band of vapor n-decane and liquid n-dodecane near 3.4 μm (3000 cm-1). n-Dodecane film thicknesses <20 μm were accurately measured in the absence of vapor, and simultaneous measurements of n-dodecane liquid film thickness and n-decane vapor mole fraction (300 ppm) were measured with <10% uncertainty for film thicknesses <10 μm. A potential application of the measurement technique is to provide accurate values of vapor mole fraction in combustion environments where strong absorption by liquid fuel or oil films on windows make conventional direct absorption measurements of the gas problematic.

Liquid fuel vaporizer and combustion chamber having an adjustable thermal conductor

DOEpatents

Powell, Michael R; Whyatt, Greg A; Howe, Daniel T; Fountain, Matthew S

2014-03-04

The efficiency and effectiveness of apparatuses for vaporizing and combusting liquid fuel can be improved using thermal conductors. For example, an apparatus having a liquid fuel vaporizer and a combustion chamber can be characterized by a thermal conductor that conducts heat from the combustion chamber to the vaporizer. The thermal conductor can be a movable member positioned at an insertion depth within the combustion chamber that corresponds to a rate of heat conduction from the combustion chamber to the vaporizer. The rate of heat conduction can, therefore, be adjusted by positioning the movable member at a different insertion depth.

VOC composition of current motor vehicle fuels and vapors, and collinearity analyses for receptor modeling.

PubMed

Chin, Jo-Yu; Batterman, Stuart A

2012-03-01

The formulation of motor vehicle fuels can alter the magnitude and composition of evaporative and exhaust emissions occurring throughout the fuel cycle. Information regarding the volatile organic compound (VOC) composition of motor fuels other than gasoline is scarce, especially for bioethanol and biodiesel blends. This study examines the liquid and vapor (headspace) composition of four contemporary and commercially available fuels: gasoline (<10% ethanol), E85 (85% ethanol and 15% gasoline), ultra-low sulfur diesel (ULSD), and B20 (20% soy-biodiesel and 80% ULSD). The composition of gasoline and E85 in both neat fuel and headspace vapor was dominated by aromatics and n-heptane. Despite its low gasoline content, E85 vapor contained higher concentrations of several VOCs than those in gasoline vapor, likely due to adjustments in its formulation. Temperature changes produced greater changes in the partial pressures of 17 VOCs in E85 than in gasoline, and large shifts in the VOC composition. B20 and ULSD were dominated by C(9) to C(16)n-alkanes and low levels of the aromatics, and the two fuels had similar headspace vapor composition and concentrations. While the headspace composition predicted using vapor-liquid equilibrium theory was closely correlated to measurements, E85 vapor concentrations were underpredicted. Based on variance decomposition analyses, gasoline and diesel fuels and their vapors VOC were distinct, but B20 and ULSD fuels and vapors were highly collinear. These results can be used to estimate fuel related emissions and exposures, particularly in receptor models that apportion emission sources, and the collinearity analysis suggests that gasoline- and diesel-related emissions can be distinguished. Copyright © 2011 Elsevier Ltd. All rights reserved.

Analysis of Fuel Vaporization, Fuel-Air Mixing, and Combustion in Integrated Mixer-Flame Holders

NASA Technical Reports Server (NTRS)

Deur, J. M.; Cline, M. C.

2004-01-01

Requirements to limit pollutant emissions from the gas turbine engines for the future High-Speed Civil Transport (HSCT) have led to consideration of various low-emission combustor concepts. One such concept is the Integrated Mixer-Flame Holder (IMFH). This report describes a series of IMFH analyses performed with KIVA-II, a multi-dimensional CFD code for problems involving sprays, turbulence, and combustion. To meet the needs of this study, KIVA-II's boundary condition and chemistry treatments are modified. The study itself examines the relationships between fuel vaporization, fuel-air mixing, and combustion. Parameters being considered include: mixer tube diameter, mixer tube length, mixer tube geometry (converging-diverging versus straight walls), air inlet velocity, air inlet swirl angle, secondary air injection (dilution holes), fuel injection velocity, fuel injection angle, number of fuel injection ports, fuel spray cone angle, and fuel droplet size. Cases are run with and without combustion to examine the variations in fuel-air mixing and potential for flashback due to the above parameters. The degree of fuel-air mixing is judged by comparing average, minimum, and maximum fuel/air ratios at the exit of the mixer tube, while flame stability is monitored by following the location of the flame front as the solution progresses from ignition to steady state. Results indicate that fuel-air mixing can be enhanced by a variety of means, the best being a combination of air inlet swirl and a converging-diverging mixer tube geometry. With the IMFH configuration utilized in the present study, flashback becomes more common as the mixer tube diameter is increased and is instigated by disturbances associated with the dilution hole flow.

Cirrus and Water Vapor Transport in the Tropical Tropopause Layer

NASA Astrophysics Data System (ADS)

Dinh, Tra Phuong

Simulations of tropical-tropopause-layer (TTL) cirrus under the influence of a large-scale equatorial Kelvin wave have been performed in two dimensions. These simulations show that, even under the influence of the large-scale wave, radiatively induced dynamics in TTL cirrus plays an important role in the transport of water vapor in the vertical direction. In a typical TTL cirrus, the heating that results from absorption of radiation by ice crystals induces a mesoscale circulation. Advection of ice and water vapor by the radiatively induced circulation leads to the persistence of the cloud and upward advection of the cloudy air. Upward advection of the cloudy air is equivalent to upward transport of water vapor when the air above the cloud is drier than the cloudy air, and downward transport otherwise. In TTL cirrus, microphysical processes also contribute to transport of water vapor in the vertical direction. Ice nucleation and growth, followed by sedimentation and sublimation, always lead to downward transport of water vapor. The magnitude of the downward transport by microphysical processes increases with the relative humidity of the air surrounding the cloud. Moisture in the surrounding environment is important because there is continuous interactions between the cloudy and environmental air throughout the cloud boundary. In our simulations, when the air surrounding the cloud is subsaturated, hence drier than the cloudy air, the magnitude of the downward transport due to microphysical processes is smaller than that of the upward transport due to the radiatively induced advection of water vapor. The net result is upward transport of water vapor, and equivalently hydration of the lower stratosphere. On the other hand, when the surrounding air is supersaturated, hence moister than the cloudy air, microphysical and radiatively induced dynamical processes work in concert to induce downward transport of water vapor, that is dehydration of the lower stratosphere. TTL

Studies of oscillatory combustion and fuel vaporization

NASA Technical Reports Server (NTRS)

Borman, G. L.; Myers, P. S.; Uyehara, O. A.

1972-01-01

Research projects involving oscillatory combustion and fuel vaporization are reported. Comparisons of experimental and theoretical droplet vaporization histories under ambient conditions such that the droplet may approach its thermodynamic critical point are presented. Experimental data on instantaneous heat transfer from a gas to a solid surface under conditions of oscillatory pressure with comparisons to an unsteady one-dimensional model are analyzed. Droplet size and velocity distribution in a spray as obtained by use of a double flash fluorescent method were investigated.

Physical Vapor Transport of Lead Telluride

NASA Technical Reports Server (NTRS)

Palosz, W.

1997-01-01

Mass transport properties of physical vapor transport of PbTe are investigated. Thermochemical analysis of the system and its implications for the growth conditions are discussed. The effect of the material preparation and pre-processing on the stoichiometry and residual gas pressure and composition, and on related mass flux is shown. A procedure leading to high mass transport rates is presented.

VOC composition of current motor vehicle fuels and vapors, and collinearity analyses for receptor modeling

PubMed Central

Chin, Jo-Yu; Batterman, Stuart A.

2015-01-01

The formulation of motor vehicle fuels can alter the magnitude and composition of evaporative and exhaust emissions occurring throughout the fuel cycle. Information regarding the volatile organic compound (VOC) composition of motor fuels other than gasoline is scarce, especially for bioethanol and bio-diesel blends. This study examines the liquid and vapor (headspace) composition of four contemporary and commercially available fuels: gasoline (<10% ethanol), E85 (85% ethanol and 15% gasoline), ultra-low sulfur diesel (ULSD), and B20 (20% soy-biodiesel and 80% ULSD). The composition of gasoline and E85 in both neat fuel and headspace vapor was dominated by aromatics and n-heptane. Despite its low gasoline content, E85 vapor contained higher concentrations of several VOCs than those in gasoline vapor, likely due to adjustments in its formulation. Temperature changes produced greater changes in the partial pressures of 17 VOCs in E85 than in gasoline, and large shifts in the VOC composition. B20 and ULSD were dominated by C9 to C16 n-alkanes and low levels of the aromatics, and the two fuels had similar headspace vapor composition and concentrations. While the headspace composition predicted using vapor–liquid equilibrium theory was closely correlated to measurements, E85 vapor concentrations were underpredicted. Based on variance decomposition analyses, gasoline and diesel fuels and their vapors VOC were distinct, but B20 and ULSD fuels and vapors were highly collinear. These results can be used to estimate fuel related emissions and exposures, particularly in receptor models that apportion emission sources, and the collinearity analysis suggests that gasoline- and diesel-related emissions can be distinguished. PMID:22154341

A Hydrocarbon Fuel Flash Vaporization System for a Pulsed Detonation Engine

DTIC Science & Technology

2006-12-01

Experiments were performed in the Air Force Research Laboratory (AFRL) Pulsed Detonation Research Facility at Wright Patterson AFB, Ohio. The PDE ...AFRL-MN-EG-TP-2006-7420 A HYDROCARBON FUEL FLASH VAPORIZATION SYSTEM FOR A PULSED DETONATION ENGINE (PREPRINT) K. Colin Tucker...85,7<&/$66,),&$7,212) E7(/(3+21(180%(5 ,QFOXGHDUHDFRGH A Hydrocarbon Fuel Flash Vaporization System for a Pulsed Detonation Engine K

Evidence of a sewer vapor transport pathway at the USEPA vapor intrusion research duplex.

PubMed

McHugh, Thomas; Beckley, Lila; Sullivan, Terry; Lutes, Chris; Truesdale, Robert; Uppencamp, Rob; Cosky, Brian; Zimmerman, John; Schumacher, Brian

2017-11-15

The role of sewer lines as preferential pathways for vapor intrusion is poorly understood. Although the importance of sewer lines for volatile organic compound (VOC) transport has been documented at a small number of sites with vapor intrusion, sewer lines are not routinely sampled during most vapor intrusion investigations. We have used a tracer study and VOC concentration measurements to evaluate the role of the combined sanitary/storm sewer line in VOC transport at the USEPA vapor intrusion research duplex in Indianapolis, Indiana. The results from the tracer study demonstrated gas migration from the sewer main line into the duplex. The migration pathway appears to be complex and may include leakage from the sewer lateral at a location below the building foundation. Vapor samples collected from the sewer line demonstrated the presence of tetrachloroethene (PCE) and chloroform in the sewer main in front of the duplex and at multiple sample locations within the sewer line upstream of the duplex. These test results combined with results from the prior multi-year study of the duplex indicate that the sewer line plays an important role in transport of VOCs from the subsurface source to the immediate vicinity of the duplex building envelope. Copyright © 2017 Elsevier B.V. All rights reserved.

Evidence of a sewer vapor transport pathway at the USEPA vapor intrusion research duplex

DOE PAGES

McHugh, Thomas; Beckley, Lila; Sullivan, Terry; ...

2017-04-26

We report the role of sewer lines as preferential pathways for vapor intrusion is poorly understood. Although the importance of sewer lines for volatile organic compound (VOC) transport has been documented at a small number of sites with vapor intrusion, sewer lines are not routinely sampled during most vapor intrusion investigations. We have used a tracer study and VOC concentration measurements to evaluate the role of the combined sanitary/storm sewer line in VOC transport at the USEPA vapor intrusion research duplex in Indianapolis, Indiana. The results from the tracer study demonstrated gas migration from the sewer main line into themore » duplex. The migration pathway appears to be complex and may include leakage from the sewer lateral at a location below the building foundation. Vapor samples collected from the sewer line demonstrated the presence of tetrachloroethene (PCE) and chloroform in the sewer main in front of the duplex and at multiple sample locations within the sewer line upstream of the duplex. Finally, these test results combined with results from the prior multi-year study of the duplex indicate that the sewer line plays an important role in transport of VOCs from the subsurface source to the immediate vicinity of the duplex building envelope.« less

Evidence of a sewer vapor transport pathway at the USEPA vapor intrusion research duplex

DOE Office of Scientific and Technical Information (OSTI.GOV)

McHugh, Thomas; Beckley, Lila; Sullivan, Terry

We report the role of sewer lines as preferential pathways for vapor intrusion is poorly understood. Although the importance of sewer lines for volatile organic compound (VOC) transport has been documented at a small number of sites with vapor intrusion, sewer lines are not routinely sampled during most vapor intrusion investigations. We have used a tracer study and VOC concentration measurements to evaluate the role of the combined sanitary/storm sewer line in VOC transport at the USEPA vapor intrusion research duplex in Indianapolis, Indiana. The results from the tracer study demonstrated gas migration from the sewer main line into themore » duplex. The migration pathway appears to be complex and may include leakage from the sewer lateral at a location below the building foundation. Vapor samples collected from the sewer line demonstrated the presence of tetrachloroethene (PCE) and chloroform in the sewer main in front of the duplex and at multiple sample locations within the sewer line upstream of the duplex. Finally, these test results combined with results from the prior multi-year study of the duplex indicate that the sewer line plays an important role in transport of VOCs from the subsurface source to the immediate vicinity of the duplex building envelope.« less

Atomization and vaporization characteristics of airblast fuel injection inside a venturi tube

NASA Technical Reports Server (NTRS)

Sun, H.; Chue, T.-H.; Lai, M.-C.; Tacina, R. R.

1993-01-01

This paper describes the experimental and numerical characterization of the capillary fuel injection, atomization, dispersion, and vaporization of liquid fuel in a coflowing air stream inside a single venturi tube. The experimental techniques used are all laser-based. Phase Doppler analyzer was used to characterize the atomization and vaporization process. Planar laser-induced fluorescence visualizations give good qualitative picture of the fuel droplet and vapor distribution. Limited quantitative capabilities of the technique are also demonstrated. A modified version of the KIVA-II was used to simulate the entire spray process, including breakup and vaporization. The advantage of venturi nozzle is demonstrated in terms of better atomization, more uniform F/A distribution, and less pressure drop. Multidimensional spray calculations can be used as a design tool only if care is taken for the proper breakup model, and wall impingement process.

Plasma reforming and partial oxidation of hydrocarbon fuel vapor to produce synthesis gas and/or hydrogen gas

DOEpatents

Kong, Peter C.; Detering, Brent A.

2003-08-19

Methods and systems for treating vapors from fuels such as gasoline or diesel fuel in an internal combustion engine, to form hydrogen gas or synthesis gas, which can then be burned in the engine to produce more power. Fuel vapor, or a mixture of fuel vapor and exhaust gas and/or air, is contacted with a plasma, to promote reforming reactions between the fuel vapor and exhaust gas to produce carbon monoxide and hydrogen gas, partial oxidation reactions between the fuel vapor and air to produce carbon monoxide and hydrogen gas, or direct hydrogen and carbon particle production from the fuel vapor. The plasma can be a thermal plasma or a non-thermal plasma. The plasma can be produced in a plasma generating device which can be preheated by contact with at least a portion of the hot exhaust gas stream, thereby decreasing the power requirements of the plasma generating device.

Plasma Reforming And Partial Oxidation Of Hydrocarbon Fuel Vapor To Produce Synthesis Gas And/Or Hydrogen Gas

DOEpatents

Kong, Peter C.; Detering, Brent A.

2004-10-19

Methods and systems are disclosed for treating vapors from fuels such as gasoline or diesel fuel in an internal combustion engine, to form hydrogen gas or synthesis gas, which can then be burned in the engine to produce more power. Fuel vapor, or a mixture of fuel vapor and exhaust gas and/or air, is contacted with a plasma, to promote reforming reactions between the fuel vapor and exhaust gas to produce carbon monoxide and hydrogen gas, partial oxidation reactions between the fuel vapor and air to produce carbon monoxide and hydrogen gas, or direct hydrogen and carbon particle production from the fuel vapor. The plasma can be a thermal plasma or a non-thermal plasma. The plasma can be produced in a plasma generating device which can be preheated by contact with at least a portion of the hot exhaust gas stream, thereby decreasing the power requirements of the plasma generating device.

Aviators intoxicated by inhalation of JP-5 fuel vapors.

PubMed

Porter, H O

1990-07-01

This case of intoxication of two aviators by inhalation of JP-5 fuel vapors emphasizes a dangerous safety hazard. One or both aviators experienced burning eyes, nausea, fatigue, impairment of eye-hand coordination, euphoria, and memory defects when their cockpit became overwhelmed with the odor of JP-5 fuel. Physical and laboratory examinations were normal except for their ill appearance, conjunctivitis, and mild hypertension, which resolved without sequelae. Exposure to JP-5 fuel vapor occurs frequently, particularly after acrobatic flight in some aircraft. The neurologic effects and insidious nature of intoxication makes continued operation under such conditions extremely hazardous. The following is recommended: in the event the odor of JP-5 or any noxious or irritating substance is detected in the cockpit, serious consideration should be given to terminating the flight, using precautionary emergency landing procedures and 100% O2.

Evidence of a sewer vapor transport pathway at the USEPA vapor intrusion research duplex

EPA Science Inventory

The role of sewer lines as preferential pathways for vapor intrusion is poorly understood. Although the importance of sewer lines for volatile organic compound (VOC) transport has been documented at a small number of sites with vapor intrusion, sewer lines are not routinely sampl...

Loop system for creating jet fuel vapor standards used in the calibration of infrared spectrophotometers and gas chromatographs.

PubMed

Reboulet, James; Cunningham, Robert; Gunasekar, Palur G; Chapman, Gail D; Stevens, Sean C

2009-02-01

A whole body inhalation study of mixed jet fuel vapor and its aerosol necessitated the development of a method for preparing vapor only standards from the neat fuel. Jet fuel is a complex mixture of components which partitions between aerosol and vapor when aspirated based on relative volatility of the individual compounds. A method was desired which could separate the vapor portion from the aerosol component to prepare standards for the calibration of infrared spectrophotometers and a head space gas chromatography system. A re-circulating loop system was developed which provided vapor only standards whose composition matched those seen in an exposure system. Comparisons of nominal concentrations in the exposure system to those determined by infrared spectrophotometry were in 92-95% agreement. Comparison of jet fuel vapor concentrations determined by infrared spectrophotometry compared to head space gas chromatography yielded a 93% overall agreement in trial runs. These levels of agreement show the loop system to be a viable method for creating jet fuel vapor standards for calibrating instruments.

Fuel Vaporization and Its Effect on Combustion in a High-Speed Compression-Ignition Engine

NASA Technical Reports Server (NTRS)

Rothrock, A M; Waldron, C D

1933-01-01

The tests discussed in this report were conducted to determine whether or not there is appreciable vaporization of the fuel injected into a high-speed compression-ignition engine during the time available for injection and combustion. The effects of injection advance angle and fuel boiling temperature were investigated. The results show that an appreciable amount of the fuel is vaporized during injection even though the temperature and pressure conditions in the engine are not sufficient to cause ignition either during or after injection, and that when the conditions are such as to cause ignition the vaporization process affects the combustion. The results are compared with those of several other investigators in the same field.

Evidence of a sewer vapor transport pathway at the USEPA ...

EPA Pesticide Factsheets

The role of sewer lines as preferential pathways for vapor intrusion is poorly understood. Although the importance of sewer lines for volatile organic compound (VOC) transport has been documented at a small number of sites with vapor intrusion, sewer lines are not routinely sampled during most vapor intrusion investigations. We have used a tracer study and VOC concentration measurements to evaluate the role of the combined sanitary/storm sewer line in VOC transport at the USEPA vapor intrusion research duplex in Indianapolis, Indiana. The results from the tracer study demonstrated gas migration from the sewer main line into the duplex. The migration pathway appears to be complex and may include leakage from the sewer lateral at a location below the building foundation. Vapor samples collected from the sewer line demonstrated the presence of tetrachloroethene (PCE) and chloroform in the sewer main in front of the duplex and at multiple sample locations within the sewer line upstream of the duplex. These test results combined with results from the prior multi-year study of the duplex indicate that the sewer line plays an important role in transport of VOCs from the subsurface source to the immediate vicinity of the duplex building envelope. Highlights • The sewer line is an important pathway for VOC transport at the USEPA duplex. • The importance of this pathway was not identified during prior study of the duplex. • Sewer lines should be routinely evaluated

Fuels processing for transportation fuel cell systems

NASA Astrophysics Data System (ADS)

Kumar, R.; Ahmed, S.

Fuel cells primarily use hydrogen as the fuel. This hydrogen must be produced from other fuels such as natural gas or methanol. The fuel processor requirements are affected by the fuel to be converted, the type of fuel cell to be supplied, and the fuel cell application. The conventional fuel processing technology has been reexamined to determine how it must be adapted for use in demanding applications such as transportation. The two major fuel conversion processes are steam reforming and partial oxidation reforming. The former is established practice for stationary applications; the latter offers certain advantages for mobile systems and is presently in various stages of development. This paper discusses these fuel processing technologies and the more recent developments for fuel cell systems used in transportation. The need for new materials in fuels processing, particularly in the area of reforming catalysis and hydrogen purification, is discussed.

Urban airshed modeling of air quality impacts of alternative transportation fuel use in Los Angeles and Atlanta

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1997-12-01

The main objective of NREL in supporting this study is to determine the relative air quality impact of the use of compressed natural gas (CNG) as an alternative transportation fuel when compared to low Reid vapor pressure (RVP) gasoline and reformulated gasoline (RFG). A table lists the criteria, air toxic, and greenhouse gas pollutants for which emissions were estimated for the alternative fuel scenarios. Air quality impacts were then estimated by performing photochemical modeling of the alternative fuel scenarios using the Urban Airshed Model Version 6.21 and the Carbon Bond Mechanism Version IV (CBM-IV) (Geary et al., 1988) Using thismore » model, the authors examined the formation and transport of ozone under alternative fuel strategies for motor vehicle transportation sources for the year 2007. Photochemical modeling was performed for modeling domains in Los Angeles, California, and Atlanta, Georgia.« less

Growth of zinc selenide crystals by physical vapor transport in microgravity

NASA Technical Reports Server (NTRS)

Rosenberger, Franz

1995-01-01

The growth of single crystals of zinc selenide was carried out by both closed ampoule physical vapor transport and effusive ampoule physical vapor transport (EAPVT). The latter technique was shown to be a much more efficient method for the seeded growth of zinc selenide, resulting in higher transport rates. Furthermore, EAPVT work on CdTe has shown that growth onto /n11/ seeds is advantageous for obtaining reduced twinning and defect densities in II-VI sphalerite materials.

Development of a Fuel Spill/Vapor Migration Modeling System.

DTIC Science & Technology

1985-12-01

transforms resulting in a direct solution of the differential equation. A second order finite * difference approximation to the Poisson equation A2*j is...7 O-A64 043 DEVELOPMENT OF A FUEL SPILL/VPOR MIGRATION MODELING 1/2 SYSTEM(U) TRACER TECHNOLOGIES ESCONDIDO Cflo IL 0 ENGLAND ET AL. DEC 85 RFURL...AFWAL-TR-85-2089 DEVELOPMENT OF A FUEL SPILL/VAPOR MIGRATION MODELING SYSTEM W.G. England * L.H. Teuscher TRACER TECHNOLOGIES DTIC *2120 WEST MISSION

Health assessment of gasoline and fuel oxygenate vapors: generation and characterization of test materials.

PubMed

Henley, Michael; Letinski, Daniel J; Carr, John; Caro, Mario L; Daughtrey, Wayne; White, Russell

2014-11-01

In compliance with the Clean Air Act regulations for fuel and fuel additive registration, the petroleum industry, additive manufacturers, and oxygenate manufacturers have conducted comparative toxicology testing on evaporative emissions of gasoline alone and gasoline containing fuel oxygenates. To mimic real world exposures, a generation method was developed that produced test material similar in composition to the re-fueling vapor from an automotive fuel tank at near maximum in-use temperatures. Gasoline vapor was generated by a single-step distillation from a 1000-gallon glass-lined kettle wherein approximately 15-23% of the starting material was slowly vaporized, separated, condensed and recovered as test article. This fraction was termed vapor condensate (VC) and was prepared for each of the seven test materials, namely: baseline gasoline alone (BGVC), or gasoline plus an ether (G/MTBE, G/ETBE, G/TAME, or G/DIPE), or gasoline plus an alcohol (G/EtOH or G/TBA). The VC test articles were used for the inhalation toxicology studies described in the accompanying series of papers in this journal. These studies included evaluations of subchronic toxicity, neurotoxicity, immunotoxicity, genotoxicity, reproductive and developmental toxicity. Results of these studies will be used for comparative risk assessments of gasoline and gasoline/oxygenate blends by the US Environmental Protection Agency. Copyright © 2014 Elsevier Inc. All rights reserved.

Transportation Fuels Markets, PADD 5

EIA Publications

2015-01-01

This study examines supply, demand, and distribution of transportation fuels in Petroleum Administration for Defense District (PADD) 5, a region that includes the western states of California, Arizona, Nevada, Oregon, Washington, Alaska, and Hawaii. For this study, transportation fuels include gasoline, diesel fuel, and jet fuel.

Permeation of Military Fuels Through Nitrile-Coated Fabrics Used for Collapsible Fuel Storage Containers

DTIC Science & Technology

2014-03-01

resistance; while decreasing the amount of acrylonitrile content improves low-temperature flexibility, but increases transport rates of military fuels through...tanks do suffer from an increase in total weight and reduced flexibility, which may influence storage, transportation , and setup of the containers...exterior surfaces. The transport of the fuel can be described by Fick’s first law (11): c J=-P x   (1) Where J is the fuel vapor flux, P is

Experimental Studies on Mass Transport of Cadmium-Zinc Telluride by Physical Vapor Transport

NASA Technical Reports Server (NTRS)

Palosz, W.; Szofran, F. R.; Lehoczky, S. L.

1995-01-01

Experimental studies on mass transport of ternary compound, Cd(1-x)Zn(x)Te by physical vapor transport (PVT) for source compositions up to X = 0.21 are presented. The effect of thermochemical (temperatures, vapor composition) and other factors (preparation of the source, crystal growth rate, temperature gradient) on composition and composition profiles of the grown crystals were investigated. A steep decrease in the mass flux with an increase in X(crystal) for X less than 0.1, and a difference in composition between the source and the deposited material have been observed. The composition profiles of the crystals were found to depend on the density and pretreatment of the source, and on the temperature gradient in the source zone. The homogeneity of the crystals improves at low undercoolings and/or when an appropriate excess of metal constituents is present in the vapor phase. The experimental results are in good agreement with our thermochemical model of this system.

Improvement of water management in a vapor feed direct methanol fuel cell

NASA Astrophysics Data System (ADS)

Masdar, M. Shahbudin; Tsujiguchi, Takuya; Nakagawa, Nobuyoshi

Water transport in a vapor feed direct methanol fuel cell was improved by fixing a hydrophobic air filter (HAF) at the cathode. Effects of the HAF properties and the fixed positions, i.e., just on the cathode surface or by providing a certain space from the surface, of the HAF on the water transport as well as the power generation performance were investigated. The water transport was evaluated by measuring the partial pressure of water, PH2O , and methanol, PCH3OH , at the anode gas layer using in situ mass spectrometry with a capillary probe and also the water and methanol fluxes across the electrode structure using a conventional method. The HAF with the highest hydrophobicity and the highest flow resistance had the strongest effect on increasing the water back diffusion from the cathode to the anode through the membrane and increasing the current density. It was noted that the HAF fixation by providing a space from the cathode surface was more effective in increasing JWCO and the current density than that of the direct placement on the cathode surface. There was an optimum distance for the HAF placement depending on the humidity of the outside air.

Climatic Analysis of Oceanic Water Vapor Transports Based on Satellite E-P Datasets

NASA Technical Reports Server (NTRS)

Smith, Eric A.; Sohn, Byung-Ju; Mehta, Vikram

2004-01-01

Understanding the climatically varying properties of water vapor transports from a robust observational perspective is an essential step in calibrating climate models. This is tantamount to measuring year-to-year changes of monthly- or seasonally-averaged, divergent water vapor transport distributions. This cannot be done effectively with conventional radiosonde data over ocean regions where sounding data are generally sparse. This talk describes how a methodology designed to derive atmospheric water vapor transports over the world oceans from satellite-retrieved precipitation (P) and evaporation (E) datasets circumvents the problem of inadequate sampling. Ultimately, the method is intended to take advantage of the relatively complete and consistent coverage, as well as continuity in sampling, associated with E and P datasets obtained from satellite measurements. Independent P and E retrievals from Special Sensor Microwave Imager (SSM/I) measurements, along with P retrievals from Tropical Rainfall Measuring Mission (TRMM) measurements, are used to obtain transports by solving a potential function for the divergence of water vapor transport as balanced by large scale E - P conditions.

Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport

NASA Technical Reports Server (NTRS)

Su, Ching-Hua; Brebrick, Robert F.; Volz, Martin P.; Burger, Arnold; Dudley, Michael; Matyi, Richard J.; Ramachandran, Narayanan; Sha, Yi-Gao; Volz, Martin P.; Shih, Hung-Dah

2001-01-01

Crystal growth by vapor transport has several distinct advantages over melt growth techniques. Among various potential benefits from material processing in reduced gravity the followings two are considered to be related to crystal growth by vapor transport: (1) elimination of the crystal weight and its influence on the defect formation and (2) reduction of natural buoyancy-driven convective flows arising from thermally and/ or solutally induced density gradient in fluids. The previous results on vapor crystal growth of semiconductors showed the improvements in surface morphology, crystalline quality, electrical properties and dopant distribution of the crystals grown in reduced gravity as compared to the crystals grown on Earth. But the mechanisms, which are responsible for the improvements and cause the gravitational effects on the complicated and coupled processes of vapor mass transport and growth kinetics, are not well understood.

Determination of As, Se, and Hg in fuel samples by in-chamber chemical vapor generation ICP OES using a Flow Blurring® multinebulizer.

PubMed

García, Miriam; Aguirre, Miguel Ángel; Canals, Antonio

2017-09-01

In this work, a new and simple analytical methodology based on in-chamber chemical vapor generation has been developed for the spectrochemical analysis of commercial fuel samples. A multiple nebulizer with three nebulization units has been employed for this purpose: One unit was used for sample introduction, while the other two were used for the necessary reagent introduction. In this way, the aerosols were mixed inside the spray chamber. Through this method, analyte transport and, therefore, sensitivity are improved in inductively coupled plasma-optical emission spectrometry. The factors (i.e., variables), influencing chemical vapor generation, have been optimized using a multivariate approach. Under optimum chemical vapor generation conditions ([NaBH 4 ] = 1.39%, [HCl] = 2.97 M, total liquid flow = 936 μL min -1 ), the proposed sample introduction system allowed the determination of arsenic, selenium, and mercury up to 5 μg g -1 with a limit of detection of 25, 140, and 13 μg kg -1 , respectively. Analyzing spiked commercial fuel samples, recovery values obtained were between 96 and 113%, and expanded uncertainty values ranged from 4 to 16%. The most striking practical conclusion of this investigation is that no carbon deposit appears on the plasma torch after extended periods of working. Graphical abstract A new and simple analytical methodology based on in-chamber chemical vapor generation has been developed for the spectrochemical analysis of commercial fuel samples in ICP OES.

Theoretical studies in support of the 3M-vapor transport (PVTOS-) experiments

NASA Technical Reports Server (NTRS)

Rosner, Daniel E.; Keyes, David E.

1989-01-01

Results are reported for a preliminary theoretical study of the coupled mass-, momentum-, and heat-transfer conditions expected within small ampoules used to grow oriented organic solid (OS-) films, by physical vapor transport (PVT) in microgravity environments. It is show that previous studies made restrictive assumptions (e.g., smallness of delta T/T, equality of molecular diffusivities) not valid under PVTOS conditions, whereas the important phenomena of sidewall gas creep, Soret transport of the organic vapor, and large vapor phase supersaturations associated with the large prevailing temperature gradients were not previously considered. Rational estimates are made of the molecular transport properties relevant to copper-phthalocyanine monomeric vapor in a gas mixture containing H2(g) and Xe(g). Efficient numerical methods have been developed and are outlined/illustrated here to making steady axisymmetric gas flow calculations within such ampoules, allowing for realistic realistic delta T/T(sub)w-values, and even corrections to Navier-Stokes-Fourier 'closure' for the governing continuum differential equations. High priority follow-on studies are outlined based on these new results.

Mass Flux of ZnSe by Physical Vapor Transport

NASA Technical Reports Server (NTRS)

Sha, Yi-Gao; Su, Ching-Hua; Palosz, W.; Volz, M. P.; Gillies, D. C.; Szofran, F. R.; Lehoczky, S. L.; Liu, Hao-Chieh; Brebrick, R. F.

1995-01-01

Mass fluxes of ZnSe by physical vapor transport (PVT) were measured in the temperature range of 1050 to 1160 C using an in-situ dynamic technique. The starting materials were either baked out or distilled under vacuum to obtain near-congruently subliming compositions. Using an optical absorption technique Zn and Se, were found to be the dominant vapor species. Partial pressures of Zn and Se, over the starting materials at temperatures between 960 and 1140 C were obtained by measuring the optical densities of the vapor phase at the wavelengths of 2138, 3405, 3508, 3613, and 3792 A. The amount and composition of the residual gas inside the experimental ampoules were measured after the run using a total pressure gauge. For the first time, the experimentally determined partial pressures of Zn and Se, and the amount and composition of the residual gas were used in a one-dimensional diffusion limited analysis of the mass transport rates for a PVT system. Reasonable agreement between the experimental and theoretical results was observed.

Quantifying liquid boundary and vapor distributions in a fuel spray by rainbow schlieren deflectometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taber Wanstall, C.; Agrawal, Ajay K.; Bittle, Joshua A.

The rainbow schlieren deflectometry (RSD) technique is used to determine the liquid boundary and the fuel volume fraction distributions in the vapor region of a high-pressure fuel spray. Experiments were conducted in a constant pressure flow vessel, whereby a customized single-hole common-rail diesel injector is used to introduce n-heptane fuel into a coflow of low-speed ambient air at two different test conditions. Only the quasi-steady period of the fuel spray is considered, and multiple injections are performed to acquire statistically significant data at an image acquisition rate of 20 kHz. An algorithm to identify the liquid boundary using intensity recordedmore » by the RSD images is presented. The results are compared against measurements obtained by the Mie scattering technique. Our results demonstrate that the RSD can be a powerful optical diagnostics technique to simultaneously quantify both the vapor and liquid regions in the high-pressure fuel sprays.« less

Quantifying liquid boundary and vapor distributions in a fuel spray by rainbow schlieren deflectometry.

PubMed

Taber Wanstall, C; Agrawal, Ajay K; Bittle, Joshua A

2017-10-20

The rainbow schlieren deflectometry (RSD) technique is used to determine the liquid boundary and the fuel volume fraction distributions in the vapor region of a high-pressure fuel spray. Experiments were conducted in a constant pressure flow vessel, whereby a customized single-hole common-rail diesel injector is used to introduce n-heptane fuel into a coflow of low-speed ambient air at two different test conditions. Only the quasi-steady period of the fuel spray is considered, and multiple injections are performed to acquire statistically significant data at an image acquisition rate of 20 kHz. An algorithm to identify the liquid boundary using intensity recorded by the RSD images is presented. The results are compared against measurements obtained by the Mie scattering technique. Results demonstrate that the RSD can be a powerful optical diagnostics technique to simultaneously quantify both the vapor and liquid regions in the high-pressure fuel sprays.

Quantifying liquid boundary and vapor distributions in a fuel spray by rainbow schlieren deflectometry

DOE PAGES

Taber Wanstall, C.; Agrawal, Ajay K.; Bittle, Joshua A.

2017-01-01

The rainbow schlieren deflectometry (RSD) technique is used to determine the liquid boundary and the fuel volume fraction distributions in the vapor region of a high-pressure fuel spray. Experiments were conducted in a constant pressure flow vessel, whereby a customized single-hole common-rail diesel injector is used to introduce n-heptane fuel into a coflow of low-speed ambient air at two different test conditions. Only the quasi-steady period of the fuel spray is considered, and multiple injections are performed to acquire statistically significant data at an image acquisition rate of 20 kHz. An algorithm to identify the liquid boundary using intensity recordedmore » by the RSD images is presented. The results are compared against measurements obtained by the Mie scattering technique. Our results demonstrate that the RSD can be a powerful optical diagnostics technique to simultaneously quantify both the vapor and liquid regions in the high-pressure fuel sprays.« less

Water-Vapor-Mediated Close-Spaced Vapor Transport Growth of Epitaxial Gallium Indium Phosphide Films on Gallium Arsenide Substrates

DOE PAGES

Greenaway, Ann L.; Bachman, Benjamin F.; Boucher, Jason W.; ...

2018-01-12

Ga 1–xIn xP is a technologically important III–V ternary semiconductor widely utilized in commercial and record-efficiency solar cells. We report the growth of Ga 1–xIn xP by water-vapor-mediated close-spaced vapor transport. Because growth of III–V semiconductors in this system is controlled by diffusion of metal oxide species, we find that congruent transport from the mixed powder source requires complete annealing to form a single alloy phase. Growth from a fully alloyed source at water vapor concentrations of ~7000 ppm in H 2 at 850 °C affords smooth films with electron mobility of 1070 cm 2 V –1 s –1 andmore » peak internal quantum efficiency of ~90% for carrier collection in a nonaqueous photoelectrochemical test cell.« less

Water-Vapor-Mediated Close-Spaced Vapor Transport Growth of Epitaxial Gallium Indium Phosphide Films on Gallium Arsenide Substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greenaway, Ann L.; Bachman, Benjamin F.; Boucher, Jason W.

Ga 1–xIn xP is a technologically important III–V ternary semiconductor widely utilized in commercial and record-efficiency solar cells. We report the growth of Ga 1–xIn xP by water-vapor-mediated close-spaced vapor transport. Because growth of III–V semiconductors in this system is controlled by diffusion of metal oxide species, we find that congruent transport from the mixed powder source requires complete annealing to form a single alloy phase. Growth from a fully alloyed source at water vapor concentrations of ~7000 ppm in H 2 at 850 °C affords smooth films with electron mobility of 1070 cm 2 V –1 s –1 andmore » peak internal quantum efficiency of ~90% for carrier collection in a nonaqueous photoelectrochemical test cell.« less

Vapor-Driven Propulsion of Catalytic Micromotors

NASA Astrophysics Data System (ADS)

Dong, Renfeng; Li, Jinxing; Rozen, Isaac; Ezhilan, Barath; Xu, Tailin; Christianson, Caleb; Gao, Wei; Saintillan, David; Ren, Biye; Wang, Joseph

2015-08-01

Chemically-powered micromotors offer exciting opportunities in diverse fields, including therapeutic delivery, environmental remediation, and nanoscale manufacturing. However, these nanovehicles require direct addition of high concentration of chemical fuel to the motor solution for their propulsion. We report the efficient vapor-powered propulsion of catalytic micromotors without direct addition of fuel to the micromotor solution. Diffusion of hydrazine vapor from the surrounding atmosphere into the sample solution is instead used to trigger rapid movement of iridium-gold Janus microsphere motors. Such operation creates a new type of remotely-triggered and powered catalytic micro/nanomotors that are responsive to their surrounding environment. This new propulsion mechanism is accompanied by unique phenomena, such as the distinct off-on response to the presence of fuel in the surrounding atmosphere, and spatio-temporal dependence of the motor speed borne out of the concentration gradient evolution within the motor solution. The relationship between the motor speed and the variables affecting the fuel concentration distribution is examined using a theoretical model for hydrazine transport, which is in turn used to explain the observed phenomena. The vapor-powered catalytic micro/nanomotors offer new opportunities in gas sensing, threat detection, and environmental monitoring, and open the door for a new class of environmentally-triggered micromotors.

Vapor-Driven Propulsion of Catalytic Micromotors

PubMed Central

Dong, Renfeng; Li, Jinxing; Rozen, Isaac; Ezhilan, Barath; Xu, Tailin; Christianson, Caleb; Gao, Wei; Saintillan, David; Ren, Biye; Wang, Joseph

2015-01-01

Chemically-powered micromotors offer exciting opportunities in diverse fields, including therapeutic delivery, environmental remediation, and nanoscale manufacturing. However, these nanovehicles require direct addition of high concentration of chemical fuel to the motor solution for their propulsion. We report the efficient vapor-powered propulsion of catalytic micromotors without direct addition of fuel to the micromotor solution. Diffusion of hydrazine vapor from the surrounding atmosphere into the sample solution is instead used to trigger rapid movement of iridium-gold Janus microsphere motors. Such operation creates a new type of remotely-triggered and powered catalytic micro/nanomotors that are responsive to their surrounding environment. This new propulsion mechanism is accompanied by unique phenomena, such as the distinct off-on response to the presence of fuel in the surrounding atmosphere, and spatio-temporal dependence of the motor speed borne out of the concentration gradient evolution within the motor solution. The relationship between the motor speed and the variables affecting the fuel concentration distribution is examined using a theoretical model for hydrazine transport, which is in turn used to explain the observed phenomena. The vapor-powered catalytic micro/nanomotors offer new opportunities in gas sensing, threat detection, and environmental monitoring, and open the door for a new class of environmentally-triggered micromotors. PMID:26285032

The competition between liquid and vapor transport in transpiring leaves.

PubMed

Rockwell, Fulton Ewing; Holbrook, N Michele; Stroock, Abraham Duncan

2014-04-01

In leaves, the transpirational flux of water exits the veins as liquid and travels toward the stomata in both the vapor and liquid phases before exiting the leaf as vapor. Yet, whether most of the evaporation occurs from the vascular bundles (perivascular), from the photosynthetic mesophyll cells, or within the vicinity of the stomatal pore (peristomatal) remains in dispute. Here, a one-dimensional model of the competition between liquid and vapor transport is developed from the perspective of nonisothermal coupled heat and water molecule transport in a composite medium of airspace and cells. An analytical solution to the model is found in terms of the energy and transpirational fluxes from the leaf surfaces and the absorbed solar energy load, leading to mathematical expressions for the proportions of evaporation accounted for by the vascular, mesophyll, and epidermal regions. The distribution of evaporation in a given leaf is predicted to be variable, changing with the local environment, and to range from dominantly perivascular to dominantly peristomatal depending on internal leaf architecture, with mesophyll evaporation a subordinate component. Using mature red oak (Quercus rubra) trees, we show that the model can be solved for a specific instance of a transpiring leaf by combining gas-exchange data, anatomical measurements, and hydraulic experiments. We also investigate the effect of radiation load on the control of transpiration, the potential for condensation on the inside of an epidermis, and the impact of vapor transport on the hydraulic efficiency of leaf tissue outside the xylem.

Modeling fission product vapor transport in the Falcon facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shepherd, I.M.; Drossinos, Y.; Benson, C.G.

1995-05-01

An extensive database of aerosol Experiments exists and has been used for checking aerosol transport codes. Data for fission product vapor transport are harder to find. Some qualitative data are available, but the Falcon thermal gradient tube tests carried out at AEA Technology`s laboratories in Winfrith, England, mark the first serious attempt to provide a set of experiments suitable for the validation of codes that predict the transport and condensation of realistic mixtures of fission product vapors. Four of these have been analyzed to check how well the computer code VICTORIA can predict the most important phenomena. Of the fourmore » experiments studied, two are reference cases (FAL-17 and FAL-19), one is a case without boric acid (FAL-18), and the other is run in a reducing atmosphere (FAL-20). The results show that once the vapors condense onto aerosols, VICTORIA can predict their deposition rather well. The dominant mechanism is thermophoresis, and each element deposits with more or less the same deposition velocity. The behavior of the vapors is harder to interpret. Essentially, it is important to know the temperature at which each element condenses. It is clear from the measurements that this temperature changed from test to test-caused mostly by the different speciation as the composition of the carrier gas and the relative concentration of other fission products changed. Only in the test with a steam atmosphere and without boric acid was the assumption valid that most of the iodine is cesium iodide and most of the cesium is cesium hydroxide. In general, VICTORIA predicts that, with the exception of cesium, there will be less variation in the speciation-and, hence, variation in the deposition-between tests than is in fact observed. VICTORIA underpredicts the volatility of most elements, and this is partly a consequence of the ideal solution assumption and partly an overestimation of vapor/aerosol interactions.« less

30 CFR 75.1906 - Transport of diesel fuel.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Transport of diesel fuel. 75.1906 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Diesel-Powered Equipment § 75.1906 Transport of diesel fuel. (a) Diesel fuel shall be transported only by diesel fuel transportation units or in safety...

30 CFR 75.1906 - Transport of diesel fuel.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Transport of diesel fuel. 75.1906 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Diesel-Powered Equipment § 75.1906 Transport of diesel fuel. (a) Diesel fuel shall be transported only by diesel fuel transportation units or in safety...

Physics-based agent to simulant correlations for vapor phase mass transport.

PubMed

Willis, Matthew P; Varady, Mark J; Pearl, Thomas P; Fouse, Janet C; Riley, Patrick C; Mantooth, Brent A; Lalain, Teri A

2013-12-15

Chemical warfare agent simulants are often used as an agent surrogate to perform environmental testing, mitigating exposure hazards. This work specifically addresses the assessment of downwind agent vapor concentration resulting from an evaporating simulant droplet. A previously developed methodology was used to estimate the mass diffusivities of the chemical warfare agent simulants methyl salicylate, 2-chloroethyl ethyl sulfide, di-ethyl malonate, and chloroethyl phenyl sulfide. Along with the diffusivity of the chemical warfare agent bis(2-chloroethyl) sulfide, the simulant diffusivities were used in an advection-diffusion model to predict the vapor concentrations downwind from an evaporating droplet of each chemical at various wind velocities and temperatures. The results demonstrate that the simulant-to-agent concentration ratio and the corresponding vapor pressure ratio are equivalent under certain conditions. Specifically, the relationship is valid within ranges of measurement locations relative to the evaporating droplet and observation times. The valid ranges depend on the relative transport properties of the agent and simulant, and whether vapor transport is diffusion or advection dominant. Published by Elsevier B.V.

Evaluation of FIDC system. [fuel vapor injector/ogniter and lean limit controller for automobile engines

NASA Technical Reports Server (NTRS)

Hall, R. A.; Dowdy, M. W.; Price, T. W.

1978-01-01

A fuel vapor injector/igniter system was evaluated for its effect on automobile engine performance, fuel economy, and exhaust emissions. Improved fuel economy and emissions, found during the single cylinder tests were not realized with a multicylinder engine. Multicylinder engine tests were conducted to compare the system with both a stock and modified stock configuration. A comparison of cylinder-to-cylinder equivalence ratio distribution was also obtained from the multicylinder engine tests. The multicylinder engine was installed in a vehicle was tested on a chassis dynamometer to compare the system with stock and modified stock configurations. The fuel vapor injector/igniter system (FIDC) configuration demonstrated approximately five percent improved fuel economy over the stock configuration, but the modified stock configuration demonstrated approximately twelve percent improved fuel economy. The hydrocarbon emissions were approximately two-hundred-thirty percent higher with the FIDC system than with the stock configuration. Both the FIDC system and the modified stock configuration adversely affected driveability. The FIDC system demonstrated a modest fuel savings, but with the penalty of increased emissions, and loss of driveability.

Bulk Growth of Wide Band Gap II-VI Compound Semiconductors by Physical Vapor Transport

NASA Technical Reports Server (NTRS)

Su, Ching-Hua

1997-01-01

The mechanism of physical vapor transport of II-VI semiconducting compounds was studied both theoretically, using a one-dimensional diffusion model, as well as experimentally. It was found that the vapor phase stoichiometry is critical in determining the vapor transport rate. The experimental heat treatment methods to control the vapor composition over the starting materials were investigated and the effectiveness of the heat treatments was confirmed by partial pressure measurements using an optical absorption technique. The effect of residual (foreign) gas on the transport rate was also studies theoretically by the diffusion model and confirmed experimentally by the measurements of total pressure and compositions of the residual gas. An in-situ dynamic technique for the transport rate measurements and a further extension of the technique that simultaneously measured the partial pressures and transport rates were performed and, for the first time, the experimentally determined mass fluxes were compared with those calculated, without any adjustable parameters, from the diffusion model. Using the information obtained from the experimental transport rate measurements as guideline high quality bulk crystal of wide band gap II-VI semiconductor were grown from the source materials which undergone the same heat treatment methods. The grown crystals were then extensively characterized with emphasis on the analysis of the crystalline structural defects.

Diffusive-convective physical vapor transport of PbTe from a Te-rich solid source

NASA Technical Reports Server (NTRS)

Zoutendyk, J.; Akutagawa, W.

1982-01-01

Crystal growth of PbTe by physical vapor transport (sublimation) in a closed ampoule is governed by the vapor species in thermal equilibrium with the solid compound. Deviations from stoichiometry in the source material cause diffusion limitation of the transport rate, which can be modified by natural (gravity-driven) convection. Mass-transport experiments have been performed using Te-rich material wherein sublimation rates have been measured in order to study the effects of natural convection in diffusion-limited vapor transport. Linear velocities for both crystal growth and evaporation (back sublimation) have been measured for transport in the direction of gravity, horizontally, and opposite to gravity. The experimental results are discussed in terms of both the one-dimensional diffusive-advective model and current, more sophisticated theory which includes natural convection. There is some evidence that convection effects from radial temperature gradients and solutal density gradients have been observed.

14 CFR 29.954 - Fuel system lightning protection.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel system lightning protection. 29.954...

14 CFR 29.954 - Fuel system lightning protection.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel system lightning protection. 29.954...

14 CFR 25.954 - Fuel system lightning protection.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel system lightning protection. 25.954...

14 CFR 29.954 - Fuel system lightning protection.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel system lightning protection. 29.954...

14 CFR 29.954 - Fuel system lightning protection.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel system lightning protection. 29.954...

14 CFR 25.954 - Fuel system lightning protection.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel system lightning protection. 25.954...

14 CFR 25.954 - Fuel system lightning protection.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel system lightning protection. 25.954...

14 CFR 25.954 - Fuel system lightning protection.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel system lightning protection. 25.954...

14 CFR 29.954 - Fuel system lightning protection.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel system lightning protection. 29.954...

14 CFR 25.954 - Fuel system lightning protection.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.954 Fuel system lightning protection. The fuel system must be designed and arranged to prevent the ignition of fuel vapor... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel system lightning protection. 25.954...

30 CFR 75.1906 - Transport of diesel fuel.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Transport of diesel fuel. 75.1906 Section 75... diesel fuel. (a) Diesel fuel shall be transported only by diesel fuel transportation units or in safety... fuel storage facilities. (c) Safety cans that leak must be promptly removed from the mine. (d) Diesel...

The Future of Low-Carbon Transportation Fuels

NASA Astrophysics Data System (ADS)

Yang, Christopher; Yeh, Sonia

2011-11-01

Petroleum fuel uses make up essentially all of transportation fuel usage today and will continue to dominate transportation fuel usage well into future without any major policy changes. This chapter focuses on low-carbon transportation fuels, specifically, biofuels, electricity and hydrogen, that are emerging options to displace petroleum based fuels. The transition to cleaner, lower carbon fuel sources will need significant technology advancement, and sustained coordination efforts among the vehicle and fuel industry and policymakers/regulators over long period of time in order to overcome market barriers, consumer acceptance, and externalities of imported oil. We discuss the unique infrastructure challenges, and compare resource, technology, economics and transitional issues for each of these fuels. While each fuel type has important technical and implementation challenges to overcome (including vehicle technologies) in order to contribute a large fraction of our total fuel demand, it is important to note that a portfolio approach will give us the best chance of meeting stringent environmental and energy security goals for a sustainable transportation future.

Fuel cell water transport

DOEpatents

Vanderborgh, Nicholas E.; Hedstrom, James C.

1990-01-01

The moisture content and temperature of hydrogen and oxygen gases is regulated throughout traverse of the gases in a fuel cell incorporating a solid polymer membrane. At least one of the gases traverses a first flow field adjacent the solid polymer membrane, where chemical reactions occur to generate an electrical current. A second flow field is located sequential with the first flow field and incorporates a membrane for effective water transport. A control fluid is then circulated adjacent the second membrane on the face opposite the fuel cell gas wherein moisture is either transported from the control fluid to humidify a fuel gas, e.g., hydrogen, or to the control fluid to prevent excess water buildup in the oxidizer gas, e.g., oxygen. Evaporation of water into the control gas and the control gas temperature act to control the fuel cell gas temperatures throughout the traverse of the fuel cell by the gases.

Numerical modeling of physical vapor transport under microgravity conditions: Effect of thermal creep and stress

NASA Technical Reports Server (NTRS)

Mackowski, Daniel W.; Knight, Roy W.

1993-01-01

One of the most promising applications of microgravity (micro-g) environments is the manufacture of exotic and high-quality crystals in closed cylindrical ampoules using physical vapor transport (PVT) processes. The quality enhancements are believed to be due to the absence of buoyant convection in the weightless environment - resulting in diffusion-limited transport of the vapor. In a typical experiment, solid-phase sample material is initially contained at one end of the ampoule. The sample is made to sublime into the vapor phase and deposit onto the opposite end by maintaining the source at an elevated temperature with respect to the deposit. Identification of the physical factors governing both the rates and uniformity of crystal growth, and the optimization of the micro-g technology, will require an accurate modeling of the vapor transport within the ampoule. Previous micro-g modeling efforts have approached the problem from a 'classical' convective/diffusion formulation, in which convection is driven by the action of buoyancy on thermal and solutal density differences. The general conclusion of these works have been that in low gravity environments the effect of buoyancy on vapor transport is negligible, and vapor transport occurs in a diffusion-limited mode. However, it has been recently recognized than in the non-isothermal (and often low total pressure) conditions encountered in ampoules, the commonly-assumed no-slip boundary condition to the differential equations governing fluid motion can be grossly unrepresentative of the actual situation. Specifically, the temperature gradients can give rise to thermal creep flows at the ampoule side walls. In addition, temperature gradients in the vapor itself can, through the action of thermal stress, lead to bulk fluid convection.

Methods of producing transportation fuel

DOEpatents

Nair, Vijay [Katy, TX; Roes, Augustinus Wilhelmus Maria [Houston, TX; Cherrillo, Ralph Anthony [Houston, TX; Bauldreay, Joanna M [Chester, GB

2011-12-27

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method for producing transportation fuel is described herein. The method for producing transportation fuel may include providing formation fluid having a boiling range distribution between -5.degree. C. and 350.degree. C. from a subsurface in situ heat treatment process to a subsurface treatment facility. A liquid stream may be separated from the formation fluid. The separated liquid stream may be hydrotreated and then distilled to produce a distilled stream having a boiling range distribution between 150.degree. C. and 350.degree. C. The distilled liquid stream may be combined with one or more additives to produce transportation fuel.

Idle speed and fuel vapor recovery control system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orzel, D.V.

1993-06-01

A method for controlling idling speed of an engine via bypass throttle connected in parallel to a primary engine throttle and for controlling purge flow through a vapor recovery system into an air/fuel intake of the engine is described, comprising the steps of: positioning the bypass throttle to decrease any difference between a desired engine idle speed and actual engine idle speed; and decreasing the purge flow when said bypass throttle position is less than a preselected fraction of a maximum bypass throttle position.

Off-Highway Transportation-Related Fuel Use

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, S.C.

2004-05-08

The transportation sector includes many subcategories--for example, on-highway, off-highway, and non-highway. Use of fuel for off-highway purposes is not well documented, nor is the number of off-highway vehicles. The number of and fuel usage for on-highway and aviation, marine, and rail categories are much better documented than for off-highway land-based use. Several sources document off-highway fuel use under specific conditions--such as use by application (e.g., recreation) or by fuel type (e.g., gasoline). There is, however, no single source that documents the total fuel used off-highway and the number of vehicles that use the fuel. This report estimates the fuel usagemore » and number of vehicles/equipment for the off-highway category. No new data have been collected nor new models developed to estimate the off-highway data--this study is limited in scope to using data that already exist. In this report, unless they are being quoted from a source that uses different terminology, the terms are used as listed below. (1) ''On-highway/on-road'' includes land-based transport used on the highway system or other paved roadways. (2) ''Off-highway/off-road'' includes land-based transport not using the highway system or other paved roadways. (3) ''Non-highway/non-road'' includes other modes not traveling on highways such as aviation, marine, and rail. It should be noted that the term ''transportation'' as used in this study is not typical. Generally, ''transportation'' is understood to mean the movement of people or goods from one point to another. Some of the off-highway equipment included in this study doesn't transport either people or goods, but it has utility in movement (e.g., a forklift or a lawn mower). Along these lines, a chain saw also has utility in movement, but it cannot transport itself (i.e., it must be carried) because it does not have wheels. Therefore, to estimate the transportation-related fuel used off-highway, transportation equipment is defined

14 CFR 25.981 - Fuel tank ignition prevention.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.981 Fuel tank... system where catastrophic failure could occur due to ignition of fuel or vapors. This must be shown by... established, as necessary, to prevent development of ignition sources within the fuel tank system pursuant to...

14 CFR 25.981 - Fuel tank ignition prevention.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.981 Fuel tank... system where catastrophic failure could occur due to ignition of fuel or vapors. This must be shown by... established, as necessary, to prevent development of ignition sources within the fuel tank system pursuant to...

14 CFR 25.981 - Fuel tank ignition prevention.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.981 Fuel tank... system where catastrophic failure could occur due to ignition of fuel or vapors. This must be shown by... established, as necessary, to prevent development of ignition sources within the fuel tank system pursuant to...

14 CFR 25.981 - Fuel tank ignition prevention.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.981 Fuel tank... system where catastrophic failure could occur due to ignition of fuel or vapors. This must be shown by... established, as necessary, to prevent development of ignition sources within the fuel tank system pursuant to...

14 CFR 25.981 - Fuel tank ignition prevention.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.981 Fuel tank... system where catastrophic failure could occur due to ignition of fuel or vapors. This must be shown by... established, as necessary, to prevent development of ignition sources within the fuel tank system pursuant to...

Heat Treatments of ZnSe Starting Materials for Physical Vapor Transport

NASA Technical Reports Server (NTRS)

Su, Ching-Hua; Palosz, W.; Feth, S.; Lehoczky, S. L.

1998-01-01

The effect of different heat treatments on stoichiometry and residual gas pressure in ZnSe physical vapor transport system was investigated. The dependence of the amount and composition of the residual gas on various heat treatment procedures is reported. Heat treatment of ZnSe starting materials by baking under the condition of dynamic vacuum to adjust its stoichiometry was performed and the effectiveness of the treatment was confirmed by the measurements of the partial pressure of Se2, P(sub Se2), in equilibrium with the heat treated samples. Optimum heat treatment procedures on the ZnSe starting material for the physical vapor transport process are discussed and verified experimentally.

Heat Treatments of ZnSe Starting Materials for Physical Vapor Transport

NASA Technical Reports Server (NTRS)

Su, Ching-Hua; Palosz, W.; Feth, S.; Lehoczky, S. L.

1997-01-01

The effect of different heat treatments on stoichiometry and residual gas pressure in ZnSe physical vapor transport system was investigated. The dependence of the amount and composition of the residual gas on various heat treatment procedures is reported. Heat treatment of ZnSe starting materials by baking under the condition of dynamic vacuum to adjust its stoichiometry was performed and the effectiveness of the treatment was confirmed by the measurements of the partial pressure of Se2, P(sub Se2), in equilibrium with the heat treated samples. Optimum heat treatment procedures on the ZnSe starting material for the physical vapor transport process are discussed and verified experimentally.

14 CFR 29.961 - Fuel system hot weather operation.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.961 Fuel system hot weather operation. Each suction lift fuel system and other fuel systems conducive to vapor... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel system hot weather operation. 29.961...

14 CFR 29.961 - Fuel system hot weather operation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.961 Fuel system hot weather operation. Each suction lift fuel system and other fuel systems conducive to vapor... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel system hot weather operation. 29.961...

14 CFR 29.961 - Fuel system hot weather operation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.961 Fuel system hot weather operation. Each suction lift fuel system and other fuel systems conducive to vapor... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel system hot weather operation. 29.961...

14 CFR 29.961 - Fuel system hot weather operation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.961 Fuel system hot weather operation. Each suction lift fuel system and other fuel systems conducive to vapor... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel system hot weather operation. 29.961...

14 CFR 29.961 - Fuel system hot weather operation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.961 Fuel system hot weather operation. Each suction lift fuel system and other fuel systems conducive to vapor... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel system hot weather operation. 29.961...

Fuel Mix Impacts from Transportation Fuel Carbon Intensity Standards in Multiple Jurisdictions

NASA Astrophysics Data System (ADS)

Witcover, J.

2017-12-01

Fuel carbon intensity standards have emerged as an important policy in jurisdictions looking to target transportation greenhouse gas (GHG) emissions for reduction. A carbon intensity standard rates transportation fuels based on analysis of lifecycle GHG emissions, and uses a system of deficits and tradable, bankable credits to reward increased use of fuels with lower carbon intensity ratings while disincentivizing use of fuels with higher carbon intensity ratings such as conventional fossil fuels. Jurisdictions with carbon intensity standards now in effect include California, Oregon, and British Columbia, all requiring 10% reductions in carbon intensity of the transport fuel pool over a 10-year period. The states and province have committed to grow demand for low carbon fuels in the region as part of collaboration on climate change policies. Canada is developing a carbon intensity standard with broader coverage, for fuels used in transport, industry, and buildings. This study shows a changing fuel mix in affected jurisdictions under the policy in terms of shifting contribution of transportation energy from alternative fuels and trends in shares of particular fuel pathways. It contrasts program designs across the jurisdictions with the policy, highlights the opportunities and challenges these pose for the alternative fuel market, and discusses the impact of having multiple policies alongside federal renewable fuel standards and sometimes local carbon pricing regimes. The results show how the market has responded thus far to a policy that incentivizes carbon saving anywhere along the supply chain at lowest cost, in ways that diverged from a priori policy expectations. Lessons for the policies moving forward are discussed.

Laser absorption-scattering technique applied to asymmetric evaporating fuel sprays for simultaneous measurement of vapor/liquid mass distributions

NASA Astrophysics Data System (ADS)

Gao, J.; Nishida, K.

2010-10-01

This paper describes an Ultraviolet-Visible Laser Absorption-Scattering (UV-Vis LAS) imaging technique applied to asymmetric fuel sprays. Continuing from the previous studies, the detailed measurement principle was derived. It is demonstrated that, by means of this technique, cumulative masses and mass distributions of vapor/liquid phases can be quantitatively measured no matter what shape the spray is. A systematic uncertainty analysis was performed, and the measurement accuracy was also verified through a series of experiments on the completely vaporized fuel spray. The results show that the Molar Absorption Coefficient (MAC) of the test fuel, which is typically pressure and temperature dependent, is the major error source. The measurement error in the vapor determination has been shown to be approximately 18% under the assumption of constant MAC of the test fuel. Two application examples of the extended LAS technique were presented for exploring the dynamics and physical insight of the evaporating fuel sprays: diesel sprays injected by group-hole nozzles and gasoline sprays impinging on an inclined wall.

Some Notes on Sparks and Ignition of Fuels

NASA Technical Reports Server (NTRS)

Fisher, Franklin A.

2000-01-01

This report compliments a concurrent analysis of the electromagnetic field threat to the fuel system of a transport aircraft. The accompanying effort assessed currents, voltages and power levels that may be induced upon fuel tank wiring from radio transmitters (inside and outside the aircraft). In addition to this, it was also essential to determine how much voltage, current, or power is required to create a fuel-vapor ignition hazard. The widely accepted minimum guideline for aircraft fuel-vapor ignition is the application of a 0.2 millijoule energy level. However, when considering radio frequency (RF) sources, this guideline is seriously inadequate. This report endeavors to bridge the gap between a traditional understanding of electrical breakdown, heating and combustion; and supplement the knowledge with available information regarding aircraft fuel-vapor ignition by RF sources

Alternative Fuels Data Center: South Dakota Transportation Data for

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Multi-fuel reformers for fuel cells used in transportation. Phase 1: Multi-fuel reformers

NASA Astrophysics Data System (ADS)

1994-05-01

DOE has established the goal, through the Fuel Cells in Transportation Program, of fostering the rapid development and commercialization of fuel cells as economic competitors for the internal combustion engine. Central to this goal is a safe feasible means of supplying hydrogen of the required purity to the vehicular fuel cell system. Two basic strategies are being considered: (1) on-board fuel processing whereby alternative fuels such as methanol, ethanol or natural gas stored on the vehicle undergo reformation and subsequent processing to produce hydrogen, and (2) on-board storage of pure hydrogen provided by stationary fuel processing plants. This report analyzes fuel processor technologies, types of fuel and fuel cell options for on-board reformation. As the Phase 1 of a multi-phased program to develop a prototype multi-fuel reformer system for a fuel cell powered vehicle, the objective of this program was to evaluate the feasibility of a multi-fuel reformer concept and to select a reforming technology for further development in the Phase 2 program, with the ultimate goal of integration with a DOE-designated fuel cell and vehicle configuration. The basic reformer processes examined in this study included catalytic steam reforming (SR), non-catalytic partial oxidation (POX) and catalytic partial oxidation (also known as Autothermal Reforming, or ATR). Fuels under consideration in this study included methanol, ethanol, and natural gas. A systematic evaluation of reforming technologies, fuels, and transportation fuel cell applications was conducted for the purpose of selecting a suitable multi-fuel processor for further development and demonstration in a transportation application.

Alternative Fuels Data Center: Alaska Transportation Data for Alternative

Science.gov Websites

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United States transportation fuel economics (1975 - 1995)

NASA Technical Reports Server (NTRS)

Alexander, A. D., III

1975-01-01

The United States transportation fuel economics in terms of fuel resources options, processing alternatives, and attendant economics for the period 1975 to 1995 are evaluated. The U.S. energy resource base is reviewed, portable fuel-processing alternatives are assessed, and selected future aircraft fuel options - JP fuel, liquid methane, and liquid hydrogen - are evaluated economically. Primary emphasis is placed on evaluating future aircraft fuel options and economics to provide guidance for future strategy of NASA in the development of aviation and air transportation research and technology.

Vapor feed direct methanol fuel cells with passive thermal-fluids management system

NASA Astrophysics Data System (ADS)

Guo, Zhen; Faghri, Amir

The present paper describes a novel technology that can be used to manage methanol and water in miniature direct methanol fuel cells (DMFCs) without the need for a complex micro-fluidics subsystem. At the core of this new technology is a unique passive fuel delivery system that allows for fuel delivery at an adjustable rate from a reservoir to the anode. Furthermore, the fuel cell is designed for both passive water management and effective carbon dioxide removal. The innovative thermal management mechanism is the key for effective operation of the fuel cell system. The vapor feed DMFC reached a power density of 16.5 mW cm -2 at current density of 60 mA cm -2. A series of fuel cell prototypes in the 0.5 W range have been successfully developed. The prototypes have demonstrated long-term stable operation, easy fuel delivery control and are scalable to larger power systems. A two-cell stack has successfully operated for 6 months with negligible degradation.

Petroleum Vapor Intrusion

EPA Pesticide Factsheets

One type of vapor intrusion is PVI, in which vapors from petroleum hydrocarbons such as gasoline, diesel, or jet fuel enter a building. Intrusion of contaminant vapors into indoor spaces is of concern.

Alternate-fueled transport aircraft possibilities

NASA Technical Reports Server (NTRS)

Aiken, W. S.

1977-01-01

The paper is organized to describe: (1) NASA's cryogenically fueled aircraft program; (2) LH2 subsonic and supersonic transport design possibilities (3) the fuel system and ground side problems associated with LH2 distribution; (4) a comparison of LCH4 with LH2; (5) the design possibilities for LCH4 fueled aircraft; and (6) a summary of where NASA's cryogenically fueled programs are headed.

Growth of urea crystals by physical vapor transport

NASA Technical Reports Server (NTRS)

Feigelson, R. S.; Route, R. K.; Kao, T.-M.

1985-01-01

This work demonstrates that high optical quality crystals of urea can be grown by the physical vapor transport method. The unique features of this method are compared with growth from methanol/water solutions. High growth rates, exceeding 2.5 mm/day, were achieved, and cm-size optical quality single crystals were obtained. Details of the growth technique and the physical properties of the crystals are presented.

NASA Experiment on Tropospheric-Stratospheric Water Vapor Transport in the Intertropical Convergence Zone

NASA Technical Reports Server (NTRS)

Page, William A.

1982-01-01

The following six papers report preliminary results obtained from a field experiment designed to study the role of tropical cumulo-nimbus clouds in the transfer of water vapor from the troposphere to the stratosphere over the region of Panama. The measurements were made utilizing special NOAA enhanced IR satellite images, radiosonde-ozonesondes and a NASA U-2 aircraft carrying. nine experiments. The experiments were provided by a group of NASA, NOAA, industry, and university scientists. Measurements included atmospheric humidity, air and cloud top temperatures, atmospheric tracer constituents, cloud particle characteristics and cloud morphology. The aircraft made a total of eleven flights from August 30 through September 18, 1980, from Howard Air Force Base, Panama; the pilots obtained horizontal and vertical profiles in and near convectively active regions and flew around and over cumulo-nimbus towers and through the extended anvils in the stratosphere. Cumulo-nimbus clouds in the tropics appear to play an important role in upward water vapor transport and may represent the principal source influencing the stratospheric water vapor budget. The clouds provide strong vertical circulation in the troposphere, mixing surface air and its trace materials (water vapor, CFM's sulfur compounds, etc.) quickly up to the tropopause. It is usually assumed that large scale mean motions or eddy scale motions transport the trace materials through the tropopause and into the stratosphere where they are further dispersed and react with other stratospheric constituents. The important step between the troposphere and stratosphere for water vapor appears to depend upon the processes occurring at or near the tropopause at the tops of the cumulo-nimbus towers. Several processes have been sugested: (1) The highest towers penetrate the tropopause and carry water in the form of small ice particles directly into the stratosphere. (2) Water vapor from the tops of the cumulonimbus clouds is

Review of the Flammability Hazard of Jet A Fuel Vapor in Civil Transport Aircraft Fuels Tanks

DOT National Transportation Integrated Search

1998-06-01

This report documents the findings of a Fuel Flammability Task Group made up of recognized fuel and combustion specialists investigating the flammability and explosiveness of fuel within an aircraft fuel tank. The task group reviewed all available re...

Transportation of spent MTR fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raisonnier, D.

1997-08-01

This paper gives an overview of the various aspects of MTR spent fuel transportation and provides in particular information about the on-going shipment of 4 spent fuel casks to the United States. Transnucleaire is a transport and Engineering Company created in 1963 at the request of the French Atomic Energy Commission. The company followed the growth of the world nuclear industry and has now six subsidiaries and affiliated companies established in countries with major nuclear programs.

Growth of zinc selenide single crystals by physical vapor transport in microgravity

NASA Technical Reports Server (NTRS)

Rosenberger, Franz

1993-01-01

The goals of this research were the optimization of growth parameters for large (20 mm diameter and length) zinc selenide single crystals with low structural defect density, and the development of a 3-D numerical model for the transport rates to be expected in physical vapor transport under a given set of thermal and geometrical boundary conditions, in order to provide guidance for an advantageous conduct of the growth experiments. In the crystal growth studies, it was decided to exclusively apply the Effusive Ampoule PVT technique (EAPVT) to the growth of ZnSe. In this technique, the accumulation of transport-limiting gaseous components at the growing crystal is suppressed by continuous effusion to vacuum of part of the vapor contents. This is achieved through calibrated leaks in one of the ground joints of the ampoule. Regarding the PVT transport rates, a 3-D spectral code was modified. After introduction of the proper boundary conditions and subroutines for the composition-dependent transport properties, the code reproduced the experimentally determined transport rates for the two cases with strongest convective flux contributions to within the experimental and numerical error.

Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport

NASA Technical Reports Server (NTRS)

Su, Ching-Hua; Brebrick, R. F.; Burger, A.; Dudley, M.; Ramachandran, N.

2003-01-01

The objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the crystals grown by vapor transport as results of buoyance-driven convection and growth interface fluctuations caused by irregular fluid-flows. ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, were grown by vapor transport technique with real time in-situ non-invasive monitoring techniques. The grown crystals were characterized extensively to correlate the grown crystal properties with the growth conditions.

Alternative Fuels Data Center: New York Transportation Data for Alternative

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DOE perspective on fuel cells in transportation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kost, R.

1996-04-01

Fuel cells are one of the most promising technologies for meeting the rapidly growing demand for transportation services while minimizing adverse energy and environmental impacts. This paper reviews the benefits of introducing fuel cells into the transportation sector; in addition to dramatically reduced vehicle emissions, fuel cells offer the flexibility than use petroleum-based or alternative fuels, have significantly greater energy efficiency than internal combustion engines, and greatly reduce noise levels during operation. The rationale leading to the emphasis on proton-exchange-membrane fuel cells for transportation applications is reviewed as are the development issues requiring resolution to achieve adequate performance, packaging, andmore » cost for use in automobiles. Technical targets for power density, specific power, platinum loading on the electrodes, cost, and other factors that become increasingly more demanding over time have been established. Fuel choice issues and pathways to reduced costs and to a renewable energy future are explored. One such path initially introduces fuel cell vehicles using reformed gasoline while-on-board hydrogen storage technology is developed to the point of allowing adequate range (350 miles) and refueling convenience. This scenario also allows time for renewable hydrogen production technologies and the required supply infrastructure to develop. Finally, the DOE Fuel Cells in Transportation program is described. The program, whose goal is to establish the technology for fuel cell vehicles as rapidly as possible, is being implemented by means of the United States Fuel Cell Alliance, a Government-industry alliance that includes Detroit`s Big Three automakers, fuel cell and other component suppliers, the national laboratories, and universities.« less

Alternative Fuels Data Center: New Hampshire Transportation Data for

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Alternative Fuels Data Center: New Mexico Transportation Data for

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Alternative Fuels Data Center: New Jersey Transportation Data for

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Alternative Fuels Data Center: North Dakota Transportation Data for

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Liquid-fueled SOFC power sources for transportation

NASA Astrophysics Data System (ADS)

Myles, K. M.; Doshi, R.; Kumar, R.; Krumpelt, M.

Traditionally, fuel cells have been developed for space or stationary terrestrial applications. As the first commercial 200-kW systems were being introduced by ONSI and Fuji Electric, the potentially much larger, but also more challenging, application in transportation was beginning to be addressed. As a result, fuel cell-powered buses have been designed and built, and R&D programs for fuel cell-powered passenger cars have been initiated. The engineering challenge of eventually replacing the internal combustion engine in buses, trucks, and passenger cars with fuel cell systems is to achieve much higher power densities and much lower costs than obtainable in systems designed for stationary applications. At present, the leading fuel cell candidate for transportation applications is, without question, the polymer electrolyte fuel cell (PEFC). Offering ambient temperature start-up and the potential for a relatively high power density, the polymer technology has attracted the interest of automotive manufacturers worldwide. But the difficulties of fuel handling for the PEFC have led to a growing interest in exploring the prospects for solid oxide fuel cells (SOFCs) operating on liquid fuels for transportation applications. Solid oxide fuel cells are much more compatible with liquid fuels (methanol or other hydrocarbons) and are potentially capable of power densities high enough for vehicular use. Two SOFC options for such use are discussed in this report.

Transportation fuels for the 21st century

EPA Science Inventory

As we enter the 21st century, policymakers face complex decisions regarding options for meeting the demand for transportation fuels. There is now a broad scientific consensus that the burning of fossil fuels has been contributing to climate change, and the transportation sector i...

Simultaneous imaging of fuel vapor mass fraction and gas-phase temperature inside gasoline sprays using two-line excitation tracer planar laser-induced fluorescence.

PubMed

Zigan, Lars; Trost, Johannes; Leipertz, Alfred

2016-02-20

This paper reports for the first time, to the best of our knowledge, on the simultaneous imaging of the gas-phase temperature and fuel vapor mass fraction distribution in a direct-injection spark-ignition (DISI) spray under engine-relevant conditions using tracer planar laser-induced fluorescence (TPLIF). For measurements in the spray, the fluorescence tracer 3-pentanone is added to the nonfluorescent surrogate fuel iso-octane, which is excited quasi-simultaneously by two different excimer lasers for two-line excitation LIF. The gas-phase temperature of the mixture of fuel vapor and surrounding gas and the fuel vapor mass fraction can be calculated from the two LIF signals. The measurements are conducted in a high-temperature, high-pressure injection chamber. The fluorescence calibration of the tracer was executed in a flow cell and extended significantly compared to the existing database. A detailed error analysis for both calibration and measurement is provided. Simultaneous single-shot gas-phase temperature and fuel vapor mass fraction fields are processed for the assessment of cyclic spray fluctuations.

EVermont Renewable Hydrogen Production and Transportation Fueling System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garabedian, Harold T.

2008-03-30

A great deal of research funding is being devoted to the use of hydrogen for transportation fuel, particularly in the development of fuel cell vehicles. When this research bears fruit in the form of consumer-ready vehicles, will the fueling infrastructure be ready? Will the required fueling systems work in cold climates as well as they do in warm areas? Will we be sure that production of hydrogen as the energy carrier of choice for our transit system is the most energy efficient and environmentally friendly option? Will consumers understand this fuel and how to handle it? Those are questions addressedmore » by the EVermont Wind to Wheels Hydrogen Project: Sustainable Transportation. The hydrogen fueling infrastructure consists of three primary subcomponents: a hydrogen generator (electrolyzer), a compression and storage system, and a dispenser. The generated fuel is then used to provide transportation as a motor fuel. EVermont Inc., started in 1993 by then governor Howard Dean, is a public-private partnership of entities interested in documenting and advancing the performance of advanced technology vehicles that are sustainable and less burdensome on the environment, especially in areas of cold climates, hilly terrain and with rural settlement patterns. EVermont has developed a demonstration wind powered hydrogen fuel producing filling system that uses electrolysis, compression to 5000 psi and a hydrogen burning vehicle that functions reliably in cold climates. And that fuel is then used to meet transportation needs in a hybrid electric vehicle whose internal combustion engine has been converted to operate on hydrogen Sponsored by the DOE EERE Hydrogen, Fuel Cells & Infrastructure Technologies (HFC&IT) Program, the purpose of the project is to test the viability of sustainably produced hydrogen for use as a transportation fuel in a cold climate with hilly terrain and rural settlement patterns. Specifically, the project addresses the challenge of building a

Transportation accident scenarios for commercial spent fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilmot, E L

1981-02-01

A spectrum of high severity, low probability, transportation accident scenarios involving commercial spent fuel is presented together with mechanisms, pathways and quantities of material that might be released from spent fuel to the environment. These scenarios are based on conclusions from a workshop, conducted in May 1980 to discuss transportation accident scenarios, in which a group of experts reviewed and critiqued available literature relating to spent fuel behavior and cask response in accidents.

Water Vapor Transport Over the Tropical Oceans During ENSO as Diagnosed from TRMM and SSM/I Data

NASA Technical Reports Server (NTRS)

Robertson, Franklin R.; Smith, Eric A.; Sohn, Byung-Ju

2000-01-01

Traditionally, large-scale water vapor transport [div Q] has been derived directly from circulation statistics in which transport processes are often depicted by mean and eddy motions. Thus detailed and accurate calculations of moisture transport terms over the globe are required. Notably, the lack of systematically spaced conventional measurements of meteorological variables over oceans has hindered understanding of the distribution and transport of water vapor. This motivates the use of indirect calculation methods in which horizontal divergence of water vapor is balanced by the evaporation minus precipitation, assuming the rate of changes of precipitable water and condensates is small over a sufficiently long time period. In order to obtain the water vapor transport, we need evaporation rate minus precipitation (E-P). Focussing on the differences in water vapor transport between El Nino and La Nina periods and their influences on atmospheric circulations, we study January, February, and March of 1998 and 1999 periods which represent El Nino and La Nina respectively. SSM/I-derived precipitation and evaporation rate from SSM/I wind and total precipitable water, in conjunction with NCEP SST and surface air temperature, are used for the calculation of the transport potential function. For the retrieval of evaporation we use a stability-dependent aerodynamic bulk scheme developed by Chou (1993). It was tested against aircraft covariance fluxes measured during cold air outbreaks over the North Atlantic Ocean. Chou et al. (1997) reported that the SSM/I retrieved latent heat flux over the western Pacific warm pool area were found to be comparable with daily mean fluxes of a ship measurements during TOGA/COARE.

Boron coating on boron nitride coated nuclear fuels by chemical vapor deposition

NASA Astrophysics Data System (ADS)

Durmazuçar, Hasan H.; Gündüz, Güngör

2000-12-01

Uranium dioxide-only and uranium dioxide-gadolinium oxide (5% and 10%) ceramic nuclear fuel pellets which were already coated with boron nitride were coated with thin boron layer by chemical vapor deposition to increase the burn-up efficiency of the fuel during reactor operation. Coating was accomplished from the reaction of boron trichloride with hydrogen at 1250 K in a tube furnace, and then sintering at 1400 and 1525 K. The deposited boron was identified by infrared spectrum. The morphology of the coating was studied by using scanning electron microscope. The plate, grainy and string (fiber)-like boron structures were observed.

Swelling kinetics and electrical charge transport in PEDOT:PSS thin films exposed to water vapor.

PubMed

Sarkar, Biporjoy; Jaiswal, Manu; Satapathy, Dillip K

2018-06-06

We report the swelling kinetics and evolution of the electrical charge transport in poly(3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT:PSS) thin films subjected to water vapor. Polymer films swell by the diffusion of water vapor and are found to undergo structural relaxations. Upon exposure to water vapor, primarily the hygroscopic PSS shell, which surrounds the conducting PEDOT-rich cores, takes up water vapor and subsequently swells. We found that the degree of swelling largely depends on the PEDOT to PSS ratio. Swelling driven microscopic rearrangement of the conducting PEDOT-rich cores in the PSS matrix strongly influences the electrical charge transport of the polymer film. Swelling induced increase as well as decrease of electrical resistance are observed in polymer films having different PEDOT to PSS ratio. This anomalous charge transport behavior in PEDOT:PSS films is reconciled by taking into account the contrasting swelling behavior of the PSS and the conducting PEDOT-rich cores leading to spatial segregation of PSS in films with PSS as a minority phase and by a net increase in mean separation between conducting PEDOT-rich cores for films having abundance of PSS.

Swelling kinetics and electrical charge transport in PEDOT:PSS thin films exposed to water vapor

NASA Astrophysics Data System (ADS)

Sarkar, Biporjoy; Jaiswal, Manu; Satapathy, Dillip K.

2018-06-01

We report the swelling kinetics and evolution of the electrical charge transport in poly(3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT:PSS) thin films subjected to water vapor. Polymer films swell by the diffusion of water vapor and are found to undergo structural relaxations. Upon exposure to water vapor, primarily the hygroscopic PSS shell, which surrounds the conducting PEDOT-rich cores, takes up water vapor and subsequently swells. We found that the degree of swelling largely depends on the PEDOT to PSS ratio. Swelling driven microscopic rearrangement of the conducting PEDOT-rich cores in the PSS matrix strongly influences the electrical charge transport of the polymer film. Swelling induced increase as well as decrease of electrical resistance are observed in polymer films having different PEDOT to PSS ratio. This anomalous charge transport behavior in PEDOT:PSS films is reconciled by taking into account the contrasting swelling behavior of the PSS and the conducting PEDOT-rich cores leading to spatial segregation of PSS in films with PSS as a minority phase and by a net increase in mean separation between conducting PEDOT-rich cores for films having abundance of PSS.

Diesel engine emissions and combustion predictions using advanced mixing models applicable to fuel sprays

NASA Astrophysics Data System (ADS)

Abani, Neerav; Reitz, Rolf D.

2010-09-01

An advanced mixing model was applied to study engine emissions and combustion with different injection strategies ranging from multiple injections, early injection and grouped-hole nozzle injection in light and heavy duty diesel engines. The model was implemented in the KIVA-CHEMKIN engine combustion code and simulations were conducted at different mesh resolutions. The model was compared with the standard KIVA spray model that uses the Lagrangian-Drop and Eulerian-Fluid (LDEF) approach, and a Gas Jet spray model that improves predictions of liquid sprays. A Vapor Particle Method (VPM) is introduced that accounts for sub-grid scale mixing of fuel vapor and more accurately and predicts the mixing of fuel-vapor over a range of mesh resolutions. The fuel vapor is transported as particles until a certain distance from nozzle is reached where the local jet half-width is adequately resolved by the local mesh scale. Within this distance the vapor particle is transported while releasing fuel vapor locally, as determined by a weighting factor. The VPM model more accurately predicts fuel-vapor penetrations for early cycle injections and flame lift-off lengths for late cycle injections. Engine combustion computations show that as compared to the standard KIVA and Gas Jet spray models, the VPM spray model improves predictions of in-cylinder pressure, heat released rate and engine emissions of NOx, CO and soot with coarse mesh resolutions. The VPM spray model is thus a good tool for efficiently investigating diesel engine combustion with practical mesh resolutions, thereby saving computer time.

Seeded Physical Vapor Transport of Cadmium-Zinc Telluride Crystals: Growth and Characterization

NASA Technical Reports Server (NTRS)

Palosz, W.; George, M. A.; Collins, E. E.; Chen, K.-T.; Zhang, Y.; Burger, A.

1997-01-01

Crystals of Cd(1-x)Zn(x)Te with x = 0.2 and 40 g in weight were grown on monocrystalline cadmium-zinc telluride seeds by closed-ampoule physical vapor transport with or without excess (Cd + Zn) in the vapor phase. Two post-growth cool-down rates were used. The crystals were characterized using low temperature photoluminescence, atomic force microscopy, chemical etching, X-ray diffraction and electrical measurements. No formation of a second, ZnTe-rich phase was observed.

A Burst Mode, Ultrahigh Temperature UF4 Vapor Core Reactor Rankine Cycle Space Power System Concept

NASA Technical Reports Server (NTRS)

Dugan, E. T.; Kahook, S. D.; Diaz, N. J.

1996-01-01

Static and dynamic neutronic analyses have been performed on an innovative burst mode (100's of MW output for a few thousand seconds) Ulvahigh Temperature Vapor Core Reactor (UTVR) space nuclear power system. The NVTR employs multiple, neutronically-coupled fissioning cores and operates on a direct, closed Rankine cycle using a disk Magnetohydrodynamic (MHD) generater for energy conversion. The UTVR includes two types of fissioning core regions: (1) the central Ultrahigh Temperature Vapor Core (UTVC) which contains a vapor mixture of highly enriched UF4 fuel and a metal fluoride working fluid and (2) the UF4 boiler column cores located in the BeO moderator/reflector region. The gaseous nature of the fuel the fact that the fuel is circulating, the multiple coupled fissioning cores, and the use of a two phase fissioning fuel lead to unique static and dynamic neutronic characteristics. Static neutronic analysis was conducted using two-dimensional S sub n, transport theory calculations and three-dimensional Monte Carlo transport theory calculations. Circulating-fuel, coupled-core point reactor kinetics equations were used for analyzing the dynamic behavior of the UTVR. In addition to including reactivity feedback phenomena associated with the individual fissioning cores, the effects of core-to-core neutronic and mass flow coupling between the UTVC and the surrounding boiler cores were also included in the dynamic model The dynamic analysis of the UTVR reveals the existence of some very effectlve inherent reactivity feedback effects that are capable of quickly stabilizing this system, within a few seconds, even when large positive reactivity insertions are imposed. If the UTVC vapor fuel density feedback is suppressed, the UTVR is still inherently stable because of the boiler core liquid-fuel volume feedback; in contrast, suppression of the vapor fuel density feedback in 'conventional" gas core cavity reactors causes them to become inherently unstable. Due to the

Ground-based research of crystal growth of II-VI compound semiconductors by physical vapor transport

NASA Technical Reports Server (NTRS)

Volz, M. P.; Gillies, D. C.; Szofran, F. R.; Lehoczky, S. L.; Su, Ching-Hua; Sha, Yi-Gao; Zhou, W.; Dudley, M.; Liu, Hao-Chieh; Brebrick, R. F.;

Transportation Fuels Markets, PADD 1 and PADD 3

EIA Publications

2016-01-01

This study examines supply, consumption, and distribution of transportation fuels in Petroleum Administration for Defense Districts (PADDs) 1 and 3, or the U.S. East Coast and the Gulf Coast, respectively. The East Coast region includes states from Maine to Florida along the U.S. Atlantic Coast. The Gulf Coast region comprises states between New Mexico in the west to Alabama in the east along the Gulf of Mexico. For this study, transportation fuels include gasoline, diesel fuel and jet fuel. Residual fuel oil supply is also analyzed where applicable.

Fabrication of solid oxide fuel cell by electrochemical vapor deposition

DOEpatents

Riley, B.; Szreders, B.E.

1988-04-26

In a high temperature solid oxide fuel cell (SOFC), the deposition of an impervious high density thin layer of electrically conductive interconnector material, such as magnesium doped lanthanum chromite, and of an electrolyte material, such as yttria stabilized zirconia, onto a porous support/air electrode substrate surface is carried out at high temperatures (/approximately/1100/degree/ /minus/ 1300/degree/C) by a process of electrochemical vapor deposition. In this process, the mixed chlorides of the specific metals involved react in the gaseous state with water vapor resulting in the deposit of an impervious thin oxide layer on the support tube/air electrode substrate of between 20--50 microns in thickness. An internal heater, such as a heat pipe, is placed within the support tube/air electrode substrate and induces a uniform temperature profile therein so as to afford precise and uniform oxide deposition kinetics in an arrangement which is particularly adapted for large scale, commercial fabrication of SOFCs.

Fabrication of solid oxide fuel cell by electrochemical vapor deposition

DOEpatents

Brian, Riley; Szreders, Bernard E.

1989-01-01

In a high temperature solid oxide fuel cell (SOFC), the deposition of an impervious high density thin layer of electrically conductive interconnector material, such as magnesium doped lanthanum chromite, and of an electrolyte material, such as yttria stabilized zirconia, onto a porous support/air electrode substrate surface is carried out at high temperatures (approximately 1100.degree.-1300.degree. C.) by a process of electrochemical vapor deposition. In this process, the mixed chlorides of the specific metals involved react in the gaseous state with water vapor resulting in the deposit of an impervious thin oxide layer on the support tube/air electrode substrate of between 20-50 microns in thickness. An internal heater, such as a heat pipe, is placed within the support tube/air electrode substrate and induces a uniform temperature profile therein so as to afford precise and uniform oxide deposition kinetics in an arrangement which is particularly adapted for large scale, commercial fabrication of SOFCs.

Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport

NASA Technical Reports Server (NTRS)

2003-01-01

The objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the crystals grown by vapor transport as results of buoyancy-driven convection and growth interface fluctuations caused by irregular fluid-flows. ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, were grown by vapor transport technique with real time in situ non-invasive monitoring techniques. The grown crystals were characterized extensively to correlate the grown crystal properties with the growth conditions. Significant effects of gravity vector orientation on the growth crystal morphology and point defect distribution were observed.

Vapor intrusion risk of fuel ether oxygenates methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME) and ethyl tert-butyl ether (ETBE): A modeling study.

PubMed

Ma, Jie; Xiong, Desen; Li, Haiyan; Ding, Yi; Xia, Xiangcheng; Yang, Yongqi

2017-06-15

Vapor intrusion of synthetic fuel additives represents a critical yet still neglected problem at sites contaminated by petroleum fuel releases. This study used an advanced numerical model to investigate the vapor intrusion potential of fuel ether oxygenates methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME), and ethyl tert-butyl ether (ETBE). Simulated indoor air concentration of these compounds can exceed USEPA indoor air screening level for MTBE (110μg/m 3 ). Our results also reveal that MTBE has much higher chance to cause vapor intrusion problems than TAME and ETBE. This study supports the statements made by USEPA in the Petroleum Vapor Intrusion (PVI) Guidance that the vertical screening criteria for petroleum hydrocarbons may not provide sufficient protectiveness for fuel additives, and ether oxygenates in particular. In addition to adverse impacts on human health, ether oxygenate vapor intrusion may also cause aesthetic problems (i.e., odour and flavour). Overall, this study points out that ether oxygenates can cause vapor intrusion problems. We recommend that USEPA consider including the field measurement data of synthetic fuel additives in the existing PVI database and possibly revising the PVI Guidance as necessary. Copyright © 2017 Elsevier B.V. All rights reserved.

The Competition between Liquid and Vapor Transport in Transpiring Leaves1[W][OPEN

PubMed Central

Rockwell, Fulton Ewing; Holbrook, N. Michele; Stroock, Abraham Duncan

2014-01-01

In leaves, the transpirational flux of water exits the veins as liquid and travels toward the stomata in both the vapor and liquid phases before exiting the leaf as vapor. Yet, whether most of the evaporation occurs from the vascular bundles (perivascular), from the photosynthetic mesophyll cells, or within the vicinity of the stomatal pore (peristomatal) remains in dispute. Here, a one-dimensional model of the competition between liquid and vapor transport is developed from the perspective of nonisothermal coupled heat and water molecule transport in a composite medium of airspace and cells. An analytical solution to the model is found in terms of the energy and transpirational fluxes from the leaf surfaces and the absorbed solar energy load, leading to mathematical expressions for the proportions of evaporation accounted for by the vascular, mesophyll, and epidermal regions. The distribution of evaporation in a given leaf is predicted to be variable, changing with the local environment, and to range from dominantly perivascular to dominantly peristomatal depending on internal leaf architecture, with mesophyll evaporation a subordinate component. Using mature red oak (Quercus rubra) trees, we show that the model can be solved for a specific instance of a transpiring leaf by combining gas-exchange data, anatomical measurements, and hydraulic experiments. We also investigate the effect of radiation load on the control of transpiration, the potential for condensation on the inside of an epidermis, and the impact of vapor transport on the hydraulic efficiency of leaf tissue outside the xylem. PMID:24572172

Numerical Modeling of Physical Vapor Transport in Contactless Crystal Growth Geometry

NASA Technical Reports Server (NTRS)

Palosz, W.; Lowry, S.; Krishnam, A.; Przekwas, A.; Grasza, K.

1998-01-01

Growth from the vapor under conditions of limited contact with the walls of the growth ampoule is beneficial for the quality of the growing crystal due to reduced stress and contamination which may be caused by interactions with the growth container. The technique may be of a particular interest for studies on crystal growth under microgravity conditions: elimination of some factors affecting the crystal quality may make interpretation of space-conducted processes more conclusive and meaningful. For that reason, and as a part of our continuing studies on 'contactless' growth technique, we have developed a computational model of crystal growth process in such system. The theoretical model was built, and simulations were performed using the commercial computational fluid dynamics code, (CFD) ACE. The code uses an implicit finite volume formulation with a gray discrete ordinate method radiation model which accounts for the diffuse absorption and reflection of radiation throughout the furnace. The three-dimensional model computes the heat transfer through the crystal, quartz, and gas both inside and outside the ampoule, and mass transport from the source to the crystal and the sink. The heat transport mechanisms by conduction, natural convection, and radiation, and mass transport by diffusion and convection are modeled simultaneously and include the heat of the phase transition at the solid-vapor interfaces. As the thermal boundary condition, temperature profile along the walls of the furnace is used. For different thermal profiles and furnace and ampoule dimensions, the crystal growth rate and development of the crystal-vapor and source-vapor interfaces (change of the interface shape and location with time) are obtained. Super/under-saturation in the ampoule is determined and critical factors determining the 'contactless' growth conditions are identified and discussed. The relative importance of the ampoule dimensions and geometry, the furnace dimensions and its

Growth kinetics of physical vapor transport processes: Crystal growth of the optoelectronic material mercurous chloride

NASA Technical Reports Server (NTRS)

Singh, N. B.; Duval, W. M.

1991-01-01

Physical vapor transport processes were studied for the purpose of identifying the magnitude of convective effects on the crystal growth process. The effects of convection on crystal quality were were studied by varying the aspect ratio and those thermal conditions which ultimately affect thermal convection during physical vapor transport. An important outcome of the present study was the observation that the convection growth rate increased up to a certain value and then dropped to a constant value for high aspect ratios. This indicated that a very complex transport had occurred which could not be explained by linear stability theory. Better quality crystals grown at a low Rayleigh number confirmed that improved properties are possible in convectionless environments.

Transportation fuels and vehicles.

DOT National Transportation Integrated Search

1999-06-24

Environmental concerns are currently the primary driver of innovation in the area of Transportation Fuels and Vehicles. Road vehicle emissions are a significant determinant of urban air quality and produce a very substantial quantity of carbon dioxid...

The comparative analysis of pre-flood season precipitation and water vapor transportation over guangdong before and after “Hiatus”

NASA Astrophysics Data System (ADS)

Fan, Lingli

2018-02-01

Relation between pre-flood season precipitation and water vapor transport in Guangdong was analysed by using the monthly observed precipitation data, reanalysis data of ERA, NCEP/NCAR, and OAFlux during 1979-2015, and the differences between before/after global warming “hiatus” were studied. Results showed that, after “hiatus”, during the pre-flood season, skin-temperature, evaporation, and the absolute humidity over the ocean near to Southern China was decreasing, and over land was increasing. So, the water cycle over the ocean had slowed down and over land had speed up. The absolute humidity difference between the ocean and the land was reduced. However, at the same time, the total wind speed in Southern China had decreased. So, the water vapor transport from the ocean to the land had reduced. The Eastern Guangdong had an anomalous convergence of meridional water vapor transport, led to increased precipitation; but in Western Guangdong, there was no meridional water vapor transport, so precipitation had a decrease.

Alternative Fuels Data Center: Leadership in CNG Propels Paper Transport

Science.gov Websites

Inc. Leadership in CNG Propels Paper Transport Inc. to someone by E-mail Share Alternative Fuels Data Center: Leadership in CNG Propels Paper Transport Inc. on Facebook Tweet about Alternative Fuels Data Center: Leadership in CNG Propels Paper Transport Inc. on Twitter Bookmark Alternative Fuels

Total Water Vapor Transport Observed in Twelve Atmospheric Rivers over the Northeastern Pacific Ocean Using Dropsondes

NASA Astrophysics Data System (ADS)

Ralph, F. M.; Iacobellis, S.; Neiman, P. J.; Cordeira, J. M.; Spackman, J. R.; Waliser, D. E.; Wick, G. A.; White, A. B.; Fairall, C. W.

2014-12-01

Demory et al (2013) recently showed that the global water cycle in climate models, including the magnitude of water vapor transport, is strongly influenced by the model's spatial resolution. The lack of offshore observations is noted as a serious limitation in determining the correct amount of transport. Due to the key role of atmospheric rivers (ARs) in determining the global distribution of water vapor, quantifying transport from ARs is a high priority. This forms a foundation of the CalWater-2 experiment aimed at sampling many ARs during 2014-2018. In February 2014, an "early-start" deployment of the NOAA G-IV research aircraft sampled 10 ARs over the northeast Pacific Ocean. On six of these flights, dropsondes were deployed in a line crossing the AR so as to robustly sample the total water vapor transport (TVT). The TVT is defined here as the sum of the vertically integrated horizontal water vapor transport (IVT) in the AR using a baseline that stretches from its warm southern (or eastern) edge to its cool northern (or western) edge. TVT includes both AR-parallel and AR-perpendicular transport. These data double the overall number of such cross-AR airborne samples suitable for calculating TVT. Analysis of TVT for these six new samples, in combination with the six previous samples from the preceding 16 years (from CalJet, WISPAR, and a Hawaii-based campaign), will be shown. A comparison will be made of the AR width and TVT determined using the well-established integrated water vapor (IWV) threshold of 2 cm, versus an IVT threshold of 250 kg m-1 s-1. Finally, the data from a well sampled case on 13 February 2014 (23 sondes with 75-100 km spacing) will be used to assess the sensitivity of TVT to dropsonde horizontal spacing and vertical resolution. This sensitivity analysis is of practical importance for the upcoming CalWater-2 field campaign where the G-IV will be used to sample many additional AR events, due to the relatively high cost of the dropsondes.

Sensor system for fuel transport vehicle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Earl, Dennis Duncan; McIntyre, Timothy J.; West, David L.

An exemplary sensor system for a fuel transport vehicle can comprise a fuel marker sensor positioned between a fuel storage chamber of the vehicle and an access valve for the fuel storage chamber of the vehicle. The fuel marker sensor can be configured to measure one or more characteristics of one or more fuel markers present in the fuel adjacent the sensor, such as when the marked fuel is unloaded at a retail station. The one or more characteristics can comprise concentration and/or identity of the one or more fuel markers in the fuel. Based on the measured characteristics ofmore » the one or more fuel markers, the sensor system can identify the fuel and/or can determine whether the fuel has been adulterated after the marked fuel was last measured, such as when the marked fuel was loaded into the vehicle.« less

Chemistry and Transport Properties for Jet Fuel Combustion

DTIC Science & Technology

2013-04-01

AFRL-OSR-VA-TR-2013-0168 Chemistry and Transport Properties for Jet Fuel Combustion Angela Violi University of Michigan...5a. CONTRACT NUMBER (U) Chemistry and Transport Properties for Jet Fuel Combustion 5b. GRANT NUMBER FA9550-09-1-0021 5c...combustors.   Although,  chemical  kinetic  mechanisms  of  hydrocarbons  have  been  widely  studied,  molecular   transport

Transport of Carbon Tetrachloride in a Fractured Vadose Zone due to Atmospheric Pressure Fluctuations, Diffusion, and Vapor Density

NASA Astrophysics Data System (ADS)

McCray, J. E.; Downs, W.; Falta, R. W.; Housley, T.

2005-12-01

DNAPL sources of carbon tetrachloride (CT) vapors are of interest at the Radioactive Waste Management Complex (RWMC) at the Idaho National Engineering and Environmental Laboratory (INEEL). The site is underlain by thick fractured basalt that includes sedimentary interbeds, each are a few meters thick. Daily atmospheric pressure fluctuations serve as driving forces for CT vapor transport in the subsurface. Other important transport processes for vapor movement include gas-phase diffusion and density-driven transport. The objective of this research is to investigate the influence and relative importance of these processes on gaseous transport of CT. Gas pressure and vapor concentration measurements were conducted at various depths in two wells. A numerical multiphase flow model (TOUGH2), calibrated to field pressure data, is used to conduct sensitivity analyses to elucidate the importance of the different transport mechanisms. Results show that the basalt is highly permeable to vertical air flow. The pressure dampening occurs mainly in the sedimentary interbeds. Model-calibrated permeability values for the interbeds are similar to those obtained in a study by the U.S. Geological Survey for shallow sediments, and an order of magnitude higher than column-scale values obtained by previous studies conducted by INEEL scientists. The transport simulations indicate that considering the effect of barometric pressure changes is critical to simulating transport of pollutants in the vadose zone above the DNAPL source. Predicted concentrations can be orders of magnitude smaller than actual concentrations if the effect is not considered. Below the DNAPL vapor source, accounting for density and diffusion alone would yield acceptable results provided that a 20% error in concentrations are acceptable, and that simulating concentrations trends (and not actual concentrations) is the primary goal.

Alternative Fuels Data Center: Biodiesel Truck Transports Capitol Christmas

Science.gov Websites

Tree Biodiesel Truck Transports Capitol Christmas Tree to someone by E-mail Share Alternative Fuels Data Center: Biodiesel Truck Transports Capitol Christmas Tree on Facebook Tweet about Alternative Fuels Data Center: Biodiesel Truck Transports Capitol Christmas Tree on Twitter Bookmark Alternative

Alternative Fuels Data Center: Michigan Transports Students in Hybrid

Science.gov Websites

Electric School Buses Michigan Transports Students in Hybrid Electric School Buses to someone by E-mail Share Alternative Fuels Data Center: Michigan Transports Students in Hybrid Electric School Electric School Buses on Twitter Bookmark Alternative Fuels Data Center: Michigan Transports Students in

Systemic molecular and cellular changes induced in rats upon inhalation of JP-8 petroleum fuel vapor.

PubMed

Hanas, Jay S; Bruce Briggs, G; Lerner, Megan R; Lightfoot, Stan A; Larabee, Jason L; Karsies, Todd J; Epstein, Robert B; Hanas, Rushie J; Brackett, Daniel J; Hocker, James R

2010-05-01

Limited information is available regarding systemic changes in mammals associated with exposures to petroleum/hydrocarbon fuels. In this study, systemic toxicity of JP-8 jet fuel was observed in a rat inhalation model at different JP-8 fuel vapor concentrations (250, 500, or 1000 mg/m(3), for 91 days). Gel electrophoresis and mass spectrometry sequencing identified the alpha-2 microglobulin protein to be elevated in rat kidney in a JP-8 dose-dependent manner. Western blot analysis of kidney and lung tissue extracts revealed JP-8 dependent elevation of inducible heat shock protein 70 (HSP70). Tissue changes were observed histologically (hematoxylin and eosin staining) in liver, kidney, lung, bone marrow, and heart, and more prevalently at medium or high JP-8 vapor phase exposures (500-1000 mg/m(3)) than at low vapor phase exposure (250 mg/m(3)) or non-JP-8 controls. JP-8 fuel-induced liver alterations included dilated sinusoids, cytoplasmic clumping, and fat cell deposition. Changes to the kidneys included reduced numbers of nuclei, and cytoplasmic dumping in the lumen of proximal convoluted tubules. JP-8 dependent lung alterations were edema and dilated alveolar capillaries, which allowed clumping of red blood cells (RBCs). Changes in the bone marrow in response to JP-8 included reduction of fat cells and fat globules, and cellular proliferation (RBCs, white blood cells-WBCs, and megakaryocytes). Heart tissue from JP-8 exposed animals contained increased numbers of inflammatory and fibroblast cells, as well as myofibril scarring. cDNA array analysis of heart tissue revealed a JP-8 dependent increase in atrial natriuretic peptide precursor mRNA and a decrease in voltage-gated potassium (K+) ion channel mRNA.

Alternative Fuels Data Center: Transportation System Efficiency

Science.gov Websites

energy use. Transportation planners and corporate decision makers can implement combinations of these corporate decision makers can help employees telework to conserve fuel. Maps & Data Average Annual Fuel

Transportation Fuels and the Hydrogen Economy

NASA Astrophysics Data System (ADS)

Gabbard, Alex

2004-11-01

An energy analysis of transportation fuels is performed for comparing automobiles and fuels currently in the marketplace as real world benchmarks projected as "hydrogen economy" requirements. Comparisons are made for ideal case average energy values at Standard Temperature and Pressure (STP) at 20°C, 1 atmosphere with no loses. "Real world" benchmarks currently in the marketplace illuminate the challenges to be met if an equivalent "hydrogen economy" is to become reality. The idea of a "hydrogen economy" is that, at some time in the future, world energy needs will be supplied in part or totally from hydrogen; in part as compared to the current "petroleum economy" that is the source of most of the world's transportation fuels and only a portion of total energy use, or hydrogen as the source of all energy consumption.

Preliminary assessment of a potassium-steam-gas vapor cycle for better fuel economy and reduced thermal pollution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fraas, A.P.

1971-08-01

The facts of fuel supply limitations, environmental quality demands, and spiraling electric generating costs strongly favor development of electric power plants that simultaneously run at higher efficiency, i.e., higher temperature, use to advantage clean fuels, and have as low a capital cost as possible. Both fuel supply and thermal pollution considerations that are becoming progressively more important strongly favor the development of a higher temperature, and more efficient, thermodynamic cycle for electric power plants. About 200,000 hr of operation of boiling potassium systems, including over 15,000 hr of potassium vapor turbine operation under the space power plant program, suggest thatmore » a potassium vapor topping cycle with a turbine inlet temperature of approximately 1500/sup 0/F merits consideration. A design study has been carried out to indicate the size, cost, and development problems of the new types of equipment required. The results indicate that a potassium vapor cycle superimposed on a conventional 1050/sup 0/F steam cycle would give an overall thermal efficiency of about 54% as compared to only 40% from a conventional steam cycle. Thus the proposed system would have a fuel consumption only 75% and a heat rejection rate only 50% that of a conventional plant. The system requires clean fuel, and takes advantage of the present trend toward eliminating SO/sub 2/, NO/sub x/ and ash emissions. Surprisingly, at first sight, the assessment at this stage shows that the capital cost may be less than that of a conventional plant. The main reason for this is use of pressurized combustion, which leads to a much smaller combustor, and thin tube walls to contain potassium at about the same pressure.« less

Chemical vapor transport of layer structured crystal β-ZrNCl

NASA Astrophysics Data System (ADS)

Ohashi, M.; Yamanaka, S.; Hattori, M.

1988-12-01

A layer structured compound β-ZrNCl is transported to a higher temperature zone with the aid of ammonium chloride as the transporting agent in the temperature range of 823-1173 K. The transport mechanism can be explained by the formation of a volatile compound (NH 4) 2ZrCl 6: β- ZrNCl+5 NH4Cl→( NH4) 2ZrCl6+4 NH3. The measurements of the vapor pressure and the mass spectrum revealed that (NH 4) 2ZrCl 6 decomposed congruently according to the equation: ( NH4) 2ZrCl6( s)→ ZrCl4( g)+2 NH3( g)+2 HCl( g) The enthalpy change for the decomposition was determined to be 533 kJ/mol. By combining the above two equations, a simplified transport equation is derived: β- ZrNCl( s)+3 HCl( g)⇌ ZrCl4( g+ NH3( g) .

Fuel cell development for transportation: Catalyst development

DOE Office of Scientific and Technical Information (OSTI.GOV)

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.

Chemical vapor deposition of Mo tubes for fuel cladding applications

DOE PAGES

Beaux, Miles F.; Vodnik, Douglas R.; Peterson, Reuben J.; ...

2018-01-31

In this study, chemical vapor deposition (CVD) techniques have been evaluated for fabrication of free-standing 0.25 mm thick molybdenum tubes with the end goal of nuclear fuel cladding applications. In order to produce tubes with the wall thickness and microstructures desirable for this application, long deposition durations on the order of 50 h with slow deposition rates were employed. A standard CVD method, involving molybdenum pentachloride reduction by hydrogen, as well as a fluidized-bed CVD (FBCVD) method was applied towards these objectives. Characterization of the tubes produced in this manner revealed regions of material with fine grain microstructure and wallmore » thickness suitable for fuel cladding applications, but lacking necessary uniformity across the length of the tubes. Finally, a path forward for the production of freestanding molybdenum tubes that possess the desired properties across their entire length has been identified and can be accomplished by future optimization of the deposition system.« less

Chemical vapor deposition of Mo tubes for fuel cladding applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beaux, Miles F.; Vodnik, Douglas R.; Peterson, Reuben J.

In this study, chemical vapor deposition (CVD) techniques have been evaluated for fabrication of free-standing 0.25 mm thick molybdenum tubes with the end goal of nuclear fuel cladding applications. In order to produce tubes with the wall thickness and microstructures desirable for this application, long deposition durations on the order of 50 h with slow deposition rates were employed. A standard CVD method, involving molybdenum pentachloride reduction by hydrogen, as well as a fluidized-bed CVD (FBCVD) method was applied towards these objectives. Characterization of the tubes produced in this manner revealed regions of material with fine grain microstructure and wallmore » thickness suitable for fuel cladding applications, but lacking necessary uniformity across the length of the tubes. Finally, a path forward for the production of freestanding molybdenum tubes that possess the desired properties across their entire length has been identified and can be accomplished by future optimization of the deposition system.« less

Dielectric Spectroscopy Study of ZnSe Grown by Physical Vapor Transport

NASA Technical Reports Server (NTRS)

Kokan, J.; Gerhardt, R.; Su, Ching-Hua

1997-01-01

The dielectric properties of ZnSe samples grown by physical vapor transport were measured as a function of frequency. Differences can be seen in the dielectric properties of samples grown under different conditions. The spectra of heat treated samples were also acquired and were found to exhibit significant deviations from those of the as grown crystals.

A Preliminary Study of the Preparation of Slurry Fuels from Vaporized Magnesium

NASA Technical Reports Server (NTRS)

Witzke, Walter R; Prok, George M; Walsh, Thomas J

1954-01-01

Slurry fuels containing extremely small particles of magnesium were prepared by concentrating the dilute slurry product resulting from the shock-cooling of magnesium metal vapors with a liquid hydrocarbon spray. A complete description of the equipment and procedure used in preparing the fuel is given. Ninety-five percent by weight of the solid particles formed by this process passed through a 100-mesh screen. The particle-size distribution of the screened fraction of one run, as determined by sedimentation analysis, indicated that 73 percent by weight of the metal particles were finer than 2 microns in equivalent spherical diameter. The purity of the solid particles ranged as high as 98.9 percent by weight of free magnesium. The screened product was concentrated by means of a bowl-type centrifuge from 0.5 to more than 50 percent by weight solids content to form an extremely viscous, clay-like mass. By addition of a surface active agent, this viscous material was converted into a pumpable slurry fuel.

Particulate Emissions Hazards Associated with Fueling Heat Engines

NASA Technical Reports Server (NTRS)

Hendricks, Robert C.; Bushnell, Dennis M.

2010-01-01

All hydrocarbon- (HC-) fueled heat engine exhaust (tailpipe) emissions (<10 to 140 nm) contribute as health hazards, including emissions from transportation vehicles (e.g., aircraft) and other HC-fueled power systems. CO2 emissions are tracked, and when mapped, show outlines of major transportation routes and cities. Particulate pollution affects living tissue and is found to be detrimental to cardiovascular and respiratory systems where ultrafine particulates directly translocate to promote vascular system diseases potentially detectable as organic vapors. This paper discusses aviation emissions, fueling, and certification issues, including heat engine emissions hazards, detection at low levels and tracking of emissions, and alternate energy sources for general aviation.

Environmental economics of lignin derived transport fuels.

PubMed

Obydenkova, Svetlana V; Kouris, Panos D; Hensen, Emiel J M; Heeres, Hero J; Boot, Michael D

2017-11-01

This paper explores the environmental and economic aspects of fast pyrolytic conversion of lignin, obtained from 2G ethanol plants, to transport fuels for both the marine and automotive markets. Various scenarios are explored, pertaining to aggregation of lignin from several sites, alternative energy carries to replace lignin, transport modalities, and allocation methodology. The results highlight two critical factors that ultimately determine the economic and/or environmental fuel viability. The first factor, the logistics scheme, exhibited the disadvantage of the centralized approach, owing to prohibitively expensive transportation costs of the low energy-dense lignin. Life cycle analysis (LCA) displayed the second critical factor related to alternative energy carrier selection. Natural gas (NG) chosen over additional biomass boosts well-to-wheel greenhouse gas emissions (WTW GHG) to a level incompatible with the reduction targets set by the U.S. renewable fuel standard (RFS). Adversely, the process' economics revealed higher profits vs. fossil energy carrier. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

The Water Vapor Source and Transport Characteristic of Rainy Seasons in Eastern China Base on Lagrangian Method

NASA Astrophysics Data System (ADS)

Shi, Y.; Jiang, Z.; Liu, Z.; Li, L.

2017-12-01

The Hybrid Single-Particle Lagrangian Integrated Trajectory platform is employed in this studyto simulate trajectories of air parcels in the different rainy seasons in East China from 1961 to 2010,with the purpose of investigating general and specific characteristics of moisture sources and the eventual relationship withprecipitation in each rainy season.The moisture transport andsource-sink characteristics of different rainy seasons have evident differences. The results show that the frontal pre-rainy season is mainly influenced bywinter monsoon system, and the precipitation is strongly affected by water vapor from Pacific Ocean (PO) and East China (EC). Afterthe onset of South China Sea Summer Monsoon (SCSMS), the moisture from Pacific Ocean decreases and from Indian Ocean monsoon area increases. Afterwards, with the northward of the rain belt, the parcels from Southwest region (South China Sea (SCS), Indian Ocean (IO) andIndo-China Peninsula and Indian Peninsula(IP)) decrease and from North region (EC, Eurasia (EA) and PO) increase. Besides, most of the land areas are water vapor sink region and most of sea areas are water vapor source region. Before the onset of SCSMS, EC and PO are two main water vapor source areas.After the onset of SCSMS, the source from PO decreasesand Indian monsoon area becomes the main vapor source region. IP is the main water vapor sink area for all four rainy seasons.As for moisture circulation characteristics, the results of vertical structure of water vapor transport indicate that the maximum water vapor transport in west and east boundaries is located in mid-troposphere and in south and north boundaries is at low-troposphere. The spatiotemporal analysis of moisture trajectory based onmultivariate empirical orthogonal function (MVEOF) indicates that the first mode has close relationship with the precipitation in North China and PDO pattern; the second mode is closely related with the precipitation in Yangtze-Huaihe river basin and

Vapor Transport Through Fractures and Other High-Permeability Paths: Its Role in the Drift Scale Test at Yucca Mountain, Nevada

NASA Astrophysics Data System (ADS)

Mukhopadhyay, S.; Tsang, Y. W.

2001-12-01

Heating unsaturated fractured tuff sets off a series of complicated thermal-hydrological (TH) processes, which result in large-scale redistribution of moisture in the host rock. Moisture redistribution arises from boiling of water near heat sources, transport of vapor away from those heat sources, condensation of that vapor in cooler rock, and subsequent gravity drainage of condensate through fractures. Vapor transport through high-permeability paths, which include both the fractures in the rock and other conduits, contributes to the evolution of these TH processes in two ways. First, the highly permeable natural fractures provide easy passage for vapor away from the heat sources. Second, these fractures and other highly permeable conduits allow vapor (and the associated energy) to escape the rock through open boundaries of the test domain. The overall impact of vapor transport on the evolution of the TH processes can be more easily understood in the context of the Drift Scale Test (DST), the largest ever in situ heater test in unsaturated fractured tuff. The DST, in which a large volume of rock has been heated for four years now, is located in the middle nonlithophysal (Tptpmn) stratigraphic unit of Yucca Mountain, Nevada. The fractured tuff in Tptpmn contains many well-connected fractures. In the DST, heating is provided by nine cannister heaters placed in a five-meter-diameter Heated Drift (HD) and fifty wing heaters installed orthogonal to the axis of the HD. The test has many instrumentation boreholes, some of which are not sealed by packers or grout and may provide passage for vapor and energy. Of these conduits, the boreholes housing the wing heaters are most important for vapor transport because of their proximity to heat sources. While part of the vapor generated by heating moves away from the heat sources through the fractures and condenses elsewhere in the rock, the rest of the vapor, under gas-pressure difference, enters the HD by way of the high

Fuel cell system for transportation applications

DOEpatents

Kumar, Romesh; Ahmed, Shabbir; Krumpelt, Michael; Myles, Kevin M.

1993-01-01

A propulsion system for a vehicle having pairs of front and rear wheels and a fuel tank. An electrically driven motor having an output shaft operatively connected to at least one of said pair of wheels is connected to a fuel cell having a positive electrode and a negative electrode separated by an electrolyte for producing dc power to operate the motor. A partial oxidation reformer is connected both to the fuel tank and to the fuel cell receives hydrogen-containing fuel from the fuel tank and water and air and for partially oxidizing and reforming the fuel with water and air in the presence of an oxidizing catalyst and a reforming catalyst to produce a hydrogen-containing gas. The hydrogen-containing gas is sent from the partial oxidation reformer to the fuel cell negative electrode while air is transported to the fuel cell positive electrode to produce dc power for operating the electric motor.

Fuel cell system for transportation applications

DOEpatents

Kumar, R.; Ahmed, S.; Krumpelt, M.; Myles, K.M.

1993-09-28

A propulsion system is described for a vehicle having pairs of front and rear wheels and a fuel tank. An electrically driven motor having an output shaft operatively connected to at least one of said pair of wheels is connected to a fuel cell having a positive electrode and a negative electrode separated by an electrolyte for producing dc power to operate the motor. A partial oxidation reformer is connected both to the fuel tank and to the fuel cell and receives hydrogen-containing fuel from the fuel tank and uses water and air for partially oxidizing and reforming the fuel in the presence of an oxidizing catalyst and a reforming catalyst to produce a hydrogen-containing gas. The hydrogen-containing gas is sent from the partial oxidation reformer to the fuel cell negative electrode while air is transported to the fuel cell positive electrode to produce dc power for operating the electric motor. 3 figures.

Water footprint of U.S. transportation fuels.

PubMed

Scown, Corinne D; Horvath, Arpad; McKone, Thomas E

2011-04-01

In the modern global economy, water and energy are fundamentally connected. Water already plays a major role in electricity generation and, with biofuels and electricity poised to gain a significant share of the transportation fuel market, water will become significantly more important for transportation energy as well. This research provides insight into the potential changes in water use resulting from increased biofuel or electricity production for transportation energy, as well as the greenhouse gas and freshwater implications. It is shown that when characterizing the water impact of transportation energy, incorporating indirect water use and defensible allocation techniques have a major impact on the final results, with anywhere between an 82% increase and a 250% decrease in the water footprint if evaporative losses from hydroelectric power are excluded. The greenhouse gas impact results indicate that placing cellulosic biorefineries in areas where water must be supplied using alternative means, such as desalination, wastewater recycling, or importation can increase the fuel's total greenhouse gas footprint by up to 47%. The results also show that the production of ethanol and petroleum fuels burden already overpumped aquifers, whereas electricity production is far less dependent on groundwater.

Impact of freeze-drying, mixing and horizontal transport on water vapor in the upper troposphere and lower stratosphere (UTLS)

NASA Astrophysics Data System (ADS)

Poshyvailo, Liubov; Ploeger, Felix; Müller, Rolf; Tao, Mengchu; Konopka, Paul; Abdoulaye Diallo, Mohamadou; Grooß, Jens-Uwe; Günther, Gebhard; Riese, Martin

2017-04-01

Water vapor in the upper troposphere and lower stratosphere (UTLS) is a key player in the global radiation budget. Therefore, a realistic representation of the water vapor distribution in this region and the involved control processes is critical for climate models, but largely uncertain hitherto. It is known that the extremely low temperatures around the tropical tropopause cause the dominant factor controlling water vapor in the lower stratosphere. Here, we focus on additional processes, such as horizontal transport between tropics and extratropics, small-scale mixing, and freeze-drying. We assess the sensitivities of simulated water vapor in the UTLS from simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS). CLaMS is a Lagrangian transport model, with a parameterization of small-scale mixing (model diffusion) which is coupled to deformations in the large-scale flow. First, to assess the robustness of water vapor with respect to the meteorological datasets we examine CLaMS driven by ECMWF ERA-Interim and the Japanese 55-year reanalysis. Second, to investigate the effects of small-scale mixing we vary the parameterized mixing strength in the CLaMS model between the reference case with the mixing strength optimized to reproduce atmospheric trace gas observations and a purely advective simulation with parameterized mixing turned off. Also calculation of Lagrangian cold points gives further insight of the processes involved. Third, to assess the effects of horizontal transport between the tropics and extratropics we carry out sensitivity simulations with horizontal transport barriers along latitude circles at the equator, 15°N/S and 35°N/S. Finally, the impact of Antarctic dehydration is estimated from additional sensitivity simulations with switched off freeze-drying in the model at high latitudes of 50°N/S. Our results show that the uncertainty in the tropical tropopause temperatures between current reanalysis datasets causes significant

Investigation of Thermal Creep and Thermal Stress Effects in Microgravity Physical Vapor Transport

NASA Technical Reports Server (NTRS)

Mackowski, D. W. (Principal Investigator); Knight, R. W. (Principal Investigator)

1996-01-01

Reported here are the results of our numerical investigation into the mechanisms which affect the transport and growth processes in physical vapor transport (PVT) crystal growth ampoules. The first part of the report consists of a brief summary of the major accomplishments and conclusions of our work. The second part consists of two manuscripts, submitted to the Journal of Crystal Growth, which provided a detailed description of the findings in our investigation.

Health assessment of gasoline and fuel oxygenate vapors: immunotoxicity evaluation.

PubMed

White, Kimber L; Peachee, Vanessa L; Armstrong, Sarah R; Twerdok, Lorraine E; Clark, Charles R; Schreiner, Ceinwen A

2014-11-01

Female Sprague Dawley rats were exposed via inhalation to vapor condensates of either gasoline or gasoline combined with various fuel oxygenates to assess potential immunotoxicity of evaporative emissions. Test articles included vapor condensates prepared from "baseline gasoline" (BGVC), or gasoline combined with methyl tertiary butyl ether (G/MTBE), ethyl t-butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), ethanol (G/EtOH), or t-butyl alcohol (G/TBA). Target concentrations were 0, 2000, 10,000 or 20,000mg/mg(3) administered for 6h/day, 5days/week for 4weeks. The antibody-forming cell (AFC) response to the T-dependent antigen, sheep erythrocyte (sRBC), was used to determine the effects of the gasoline vapor condensates on the humoral components of the immune system. Exposure to BGVC, G/MTBE, G/TAME, and G/TBA did not result in significant changes in the IgM AFC response to sRBC, when evaluated as either specific activity (AFC/10(6) spleen cells) or as total spleen activity (AFC/spleen). Exposure to G/EtOH and G/DIPE resulted in a dose-dependent decrease in the AFC response, reaching the level of statistical significance only at the high 20,000mg/m(3) level. Exposure to G/ETBE resulted in a statistically significant decrease in the AFC response at the middle (10,000mg/m(3)) and high (20,000mg/m(3)) exposure concentrations. Copyright © 2014 Elsevier Inc. All rights reserved.

Transportation Fuels Markets, Midwest and Rocky Mountain

EIA Publications

2017-01-01

A new study commissioned by the U.S. Energy Information Administration (EIA), finds that changes in North American energy markets over the past decade have strengthened the supply of transportation fuels including motor gasoline, distillates, and jet fuel in the Midwest and Rocky Mountain regions.

Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport

NASA Technical Reports Server (NTRS)

Su, Ching-Hua; Brebrick, R. F.; Dudley, M.; Ramachandran, N.; Curreri, Peter A. (Technical Monitor)

2002-01-01

The objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the crystals grown by vapor transport as results of buoyance-driven convection and growth interface fluctuations caused by irregular fluid-flows. ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, were grown by vapor transport technique with real time in-situ non-invasive monitoring techniques. The grown crystals were characterized extensively to correlate the grown crystal properties with the growth conditions. The following are the research progress in the past two years. In-situ monitoring of partial pressure by optical absorption technique and visual observation of the growing crystal were performed during vapor growth of ZnSe. Low-temperature photoluminescence (PL) spectra and glow discharge mass spectroscopy (GDMS) were measured on ZnSe starting materials provided by various vendors and on bulk crystals grown from these starting materials by physical vapor transport (PVT) to study the effects of purification and contamination during crystal growth process. Optical characterization was performed on wafers sliced from the grown crystals of ZnSe, ZnTe and ZnSe(1-x),Te(x), (0

Short circuit of water vapor and polluted air to the global stratosphere by convective transport over the Tibetan Plateau

PubMed Central

Fu, Rong; Hu, Yuanlong; Wright, Jonathon S.; Jiang, Jonathan H.; Dickinson, Robert E.; Chen, Mingxuan; Filipiak, Mark; Read, William G.; Waters, Joe W.; Wu, Dong L.

2006-01-01

During boreal summer, much of the water vapor and CO entering the global tropical stratosphere is transported over the Asian monsoon/Tibetan Plateau (TP) region. Studies have suggested that most of this transport is carried out either by tropical convection over the South Asian monsoon region or by extratropical convection over southern China. By using measurements from the newly available National Aeronautics and Space Administration Aura Microwave Limb Sounder, along with observations from the Aqua and Tropical Rainfall-Measuring Mission satellites, we establish that the TP provides the main pathway for cross-tropopause transport in this region. Tropospheric moist convection driven by elevated surface heating over the TP is deeper and detrains more water vapor, CO, and ice at the tropopause than over the monsoon area. Warmer tropopause temperatures and slower-falling, smaller cirrus cloud particles in less saturated ambient air at the tropopause also allow more water vapor to travel into the lower stratosphere over the TP, effectively short-circuiting the slower ascent of water vapor across the cold tropical tropopause over the monsoon area. Air that is high in water vapor and CO over the Asian monsoon/TP region enters the lower stratosphere primarily over the TP, and it is then transported toward the Asian monsoon area and disperses into the large-scale upward motion of the global stratospheric circulation. Thus, hydration of the global stratosphere could be especially sensitive to changes of convection over the TP. PMID:16585523

Alternative Fuels Data Center: Maryland Transportation Data for Alternative

Science.gov Websites

: BioFuels Atlas from the National Renewable Energy Laboratory Case Studies Video thumbnail for Baltimore on YouTube Video thumbnail for Maryland County Fleet Uses Wide Variety of Alternative Fuels Maryland /Jt3ftCMissc Video thumbnail for Veolia Transportation Converts Taxi Fleet to Propane Veolia Transportation

Multi-fuel reformers for fuel cells used in transportation: Assessment of hydrogen storage technologies

NASA Astrophysics Data System (ADS)

1994-03-01

This report documents a portion of the work performed on Multi-fuel Reformers for Fuel Cells Used in Transportation. One objective of this program is to develop advanced fuel processing systems to reform methanol, ethanol, natural gas, and other hydrocarbons into hydrogen for use in transportation fuel cell systems, while a second objective is to develop better systems for on-board hydrogen storage. This report examines techniques and technology available for storage of pure hydrogen on board a vehicle as pure hydrogen of hydrides. The report focuses separately on near and far-term technologies, with particular emphasis on the former. Development of lighter, more compact near-term storage systems is recommended to enhance competitiveness and simplify fuel cell design. The far-term storage technologies require substantial applied research in order to become serious contenders.

Crystal Growth of ZnSe by Physical Vapor Transport: A Modeling Study

NASA Technical Reports Server (NTRS)

Ramachandran, Narayanan; Su, Ching-Hua

1998-01-01

Crystal growth from the vapor phase has various advantages over melt growth. The main advantage is from a lower processing temperature which makes the process more amenable in instances where the melting temperature of the crystal is high. Other benefits stem from the inherent purification mechanism in the process due to differences in the vapor pressures of the native elements and impurities, and the enhanced interfacial morphological stability during the growth process. Further, the implementation of Physical Vapor Transport (PVT) growth in closed ampoules affords experimental simplicity with minimal needs for complex process control which makes it an ideal candidate for space investigations in systems where gravity tends to have undesirable effects on the growth process. Bulk growth of wide band gap II-VI semiconductors by physical vapor transport has been developed and refined over the past several years at NASA MSFC. Results from a modeling study of PVT crystal growth of ZnSe arc reported in this paper. The PVI process is numerically investigated using both two-dimensional and fully three-dimensional formulation of the governing equations and associated boundary conditions. Both the incompressible Boussinesq approximation and the compressible model are tested to determine the influence of gravity on the process and to discern the differences between the two approaches. The influence of a residual gas is included in the models. The preliminary results show that both the incompressible and compressible approximations provide comparable results and the presence of a residual gas tends to measurably reduce the mass flux in the system. Detailed flow, thermal and concentration profiles will be provided in the final manuscript along with computed heat and mass transfer rates. Comparisons with the 1-D model will also be provided.

Experimental Study of the Low Supersaturation Nucleation in Crystal Growth by Contactless Physical Vapor Transport

NASA Technical Reports Server (NTRS)

Grasza, K.; Palosz, W.; Trivedi, S. B.

1998-01-01

The process of the development of the nuclei and of subsequent seeding in 'contactless' physical vapor transport is investigated experimentally. Consecutive stages of the Low Supersaturation Nucleation in 'contactless' geometry for growth of CdTe crystals from the vapor are shown. The effects of the temperature field, geometry of the system, and experimental procedures on the process are presented and discussed. The experimental results are found to be consistent with our earlier numerical modeling results.

Spent Nuclear Fuel Transport Reliability Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jy-An John; Wang, Hong; Jiang, Hao

This conference paper was orignated and shorten from the following publisehd PTS documents: 1. Jy-An Wang, Hao Jiang, and Hong Wang, Dynamic Deformation Simulation of Spent Nuclear Fuel Assembly and CIRFT Deformation Sensor Stability Investigation, ORNL/SPR-2015/662, November 2015. 2. Jy-An Wang, Hong Wang, Mechanical Fatigue Testing of High-Burnup Fuel for Transportation Applications, NUREG/CR-7198, ORNL/TM-2014/214, May 2015. 3. Jy-An Wang, Hong Wang, Hao Jiang, Yong Yan, Bruce Bevard, Spent Nuclear Fuel Vibration Integrity Study 16332, WM2016 Conference, March 6 10, 2016, Phoenix, Arizona.

Deposition of naphthalene and tetradecane vapors in models of the human respiratory system.

PubMed

Zhang, Zhe; Kleinstreuer, Clement

2011-01-01

Jet-propulsion fuel (particularly JP-8) is currently being used worldwide, exposing especially Air Force personnel and people living near airfields to JP-8 vapors and aerosols during aircraft fueling, maintenance operations, and/or cold starts. JP-8 is a complex mixture containing >200, mostly toxic, aliphatic and aromatic hydrocarbon compounds of which tetradecane and naphthalene were chosen as two representative chemical markers for computer simulations. Thus, transport and deposition of naphthalene and tetradecane vapors have been simulated in models of the human respiratory system. The inspiratory deposition data were analyzed in terms of regional deposition fractions (DFs) and deposition enhancement factors (DEF). The vapor depositions are affected by vapor properties (e.g. diffusivity), airway geometric features, breathing patterns, inspiratory flow rates, as well as airway-wall absorption parameter. Specifically, the respiratory uptake of vapors is greatly influenced by the degree of airway-wall absorption. For example, being an almost insoluble species in the mucus layer, the deposition of tetradecane vapor is nearly zero in the extrathoracic and tracheobronchial (TB) airways, that is, the DF is <1%. The remaining vapors may penetrate further and deposit in the alveolar airways. The DF of tetradecane vapors during inhalation in the alveolar region can range from 7% to 24%, depending on breathing waveform, inhalation rate, and thickness of the mucus layer. In contrast, naphthalene vapor almost completely deposits in the extrathoracic and TB airways and hardly moves downstream and deposits in the respiratory zone. The DFs of naphthalene vapor in the extrathoracic airways from nasal/oral to trachea under normal breathing conditions (Q = 15-60 L/min) are about 12-34%, although they are about 66-87% in the TB airways. In addition, the variation of breathing routes (say, from nasal breathing to oral breathing) may influence the vapor deposition in the

Flood Runoff in Relation to Water Vapor Transport by Atmospheric Rivers Over the Western United States, 1949-2015

NASA Astrophysics Data System (ADS)

Konrad, Christopher P.; Dettinger, Michael D.

2017-11-01

Atmospheric rivers (ARs) have a significant role in generating floods across the western United States. We analyze daily streamflow for water years 1949 to 2015 from 5,477 gages in relation to water vapor transport by ARs using a 6 h chronology resolved to 2.5° latitude and longitude. The probability that an AR will generate 50 mm/d of runoff in a river on the Pacific Coast increases from 12% when daily mean water vapor transport, DVT, is greater than 300 kg m-1 s-1 to 54% when DVT > 600 kg m-1 s-1. Extreme runoff, represented by the 99th quantile of daily values, doubles from 80 mm/d at DVT = 300 kg m-1 s-1 to 160 mm/d at DVT = 500 kg m-1 s-1. Forecasts and predictions of water vapor transport by atmospheric rivers can support flood risk assessment and estimates of future flood frequencies and magnitude in the western United States.

Energy and water vapor transport across a simplified cloud-clear air interface

NASA Astrophysics Data System (ADS)

Gallana, L.; Di Savino, S.; De Santi, F.; Iovieno, M.; Tordella, D.

2014-11-01

We consider a simplified physics of the could interface where condensation, evaporation and radiation are neglected and momentum, thermal energy and water vapor transport is represented in terms of the Boussinesq model coupled to a passive scalar transport equation for the vapor. The interface is modeled as a layer separating two isotropic turbulent regions with different kinetic energy and vapor concentration. In particular, we focus on the small scale part of the inertial range of the atmospheric boundary layer as well as on the dissipative range of scales which are important to the micro-physics of warm clouds. We have numerically investigated stably stratified interfaces by locally perturbing at an initial instant the standard temperature lapse rate at the cloud interface and then observing the temporal evolution of the system. When the buoyancy term becomes of the same order of the inertial one, we observe a spatial redistribution of the kinetic energy which produce a concomitant pit of kinetic energy within the mixing layer. In this situation, the mixing layer contains two interfacial regions with opposite kinetic energy gradient, which in turn produces two intermittent sublayers in the velocity fluctuations field. This changes the structure of the field with respect to the corresponding non-stratified shearless mixing: the communication between the two turbulent region is weak, and the growth of the mixing layer stops. These results are discussed with respect to Large Eddy Simulations data for the Planetary Boundary Layers.

Molecular-Flow Properties of RIB Type Vapor-Transport Systems Using a Fast-Valve

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alton, Gerald D; Bilheux, Hassina Z; Zhang, Y.

2014-01-01

The advent of the fast-valve device, described previously, permits measurement of molecular-flow times of chemically active or inactive gaseous species through radioactive ion beam (RIB) target ion source systems, independent of size, geometry and materials of construction. Thus, decay losses of short-half-life RIBs can be determined for a given target/vapor-transport system in advance of on-line operation, thereby ascertaining the feasibility of the system design for successful processing of a given isotope. In this article, molecular-flow-time theory and experimentally measured molecular-flow time data are given for serial- and parallel-coupled Ta metal RIB vapor-transport systems similar to those used at ISOL basedmore » RIB facilities. In addition, the effect of source type on the molecular-flow time properties of a given system is addressed, and a chemical passivation method for negating surface adsorption enthalpies for chemically active gaseous species on Ta surfaces is demonstrated.« less

Evidence of thermal transport anisotropy in stable glasses of vapor deposited organic molecules

NASA Astrophysics Data System (ADS)

Ràfols-Ribé, Joan; Dettori, Riccardo; Ferrando-Villalba, Pablo; Gonzalez-Silveira, Marta; Abad, Llibertat; Lopeandía, Aitor F.; Colombo, Luciano; Rodríguez-Viejo, Javier

2018-03-01

Vapor deposited organic glasses are currently in use in many optoelectronic devices. Their operation temperature is limited by the glass transition temperature of the organic layers and thermal management strategies become increasingly important to improve the lifetime of the device. Here we report the unusual finding that molecular orientation heavily influences heat flow propagation in glassy films of small molecule organic semiconductors. The thermal conductivity of vapor deposited thin-film semiconductor glasses is anisotropic and controlled by the deposition temperature. We compare our data with extensive molecular dynamics simulations to disentangle the role of density and molecular orientation on heat propagation. Simulations do support the view that thermal transport along the backbone of the organic molecule is strongly preferred with respect to the perpendicular direction. This is due to the anisotropy of the molecular interaction strength that limits the transport of atomic vibrations. This approach could be used in future developments to implement small molecule glassy films in thermoelectric or other organic electronic devices.

New High Performance Water Vapor Membranes to Improve Fuel Cell Balance of Plant Efficiency and Lower Costs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagener, Earl; Topping, Chris; Morgan, Brad

Hydrogen fuel cells are currently one of the more promising long term alternative energy options and out of the range of fuel cell technologies under development, proton exchange membranes [PEMs] have the advantage of being able to deliver high power density at relatively low operating temperatures. This is essential for systems such as fuel cell vehicles (FCV) and many stationary applications that undergoing frequent on/off cycling. One of the biggest challenges for PEM systems is the need to maintain a high level of hydration in the cell to enable efficient conduction of protons from the anode to the cathode. Inmore » addition to significant power loss, low humidity conditions lead to increased stress on the membranes which can result in both physical and chemical degradation. Therefore, an effective fuel cell humidifier can be critical for the efficient operation and durability of the system under high load and low humidity conditions. The most common types of water vapor transport (WVT) devices are based on water permeable membrane based separators. Successful membranes must effectively permeate water vapor while restricting crossover of air, and be robust to the temperature and humidity fluctuations experienced in fuel cell systems. DOE sponsored independent evaluations indicate that balance of plant components, including humidification devices, make up more than half of the cost of current automotive fuel cell systems. Despite its relatively widespread us in other applications, the current industry standard perfluorosulfonic acid based Nafion® remains expensive compared with non-perfluorinated polymer membranes. During Phase II of this project, we demonstrated the improved performance of our semi-fluorinated perfluorocyclobutyl polymer based membranes compared with the current industry standard perfluorosulfonic acid based Nafion®, at ~ 50% lower cost. Building on this work, highlights of our Phase IIB developments, in close collaboration with leading

Transport Studies and Modeling in PEM Fuel Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mittelsteadt, Cortney K.; Xu, Hui; Brawn, Shelly

2014-07-30

This project’s aim was to develop fuel cell components (i.e. membranes, gas-diffusion media (GDM), bipolar plates and flow fields) that possess specific properties (i.e. water transport and conductivity). A computational fluid dynamics model was developed to elucidate the effect of certain parameters on these specific properties. Ultimately, the model will be used to determine sensitivity of fuel cell performance to component properties to determine limiting components and to guide research. We have successfully reached our objectives and achieved most of the milestones of this project. We have designed and synthesized a variety of hydrocarbon block polymer membranes with lower equivalentmore » weight, structure, chemistry, phase separation and process conditions. These membranes provide a broad selection with optimized water transport properties. We have also designed and constructed a variety of devices that are capable of accurately measuring the water transport properties (water uptake, water diffusivity and electro-osmatic drag) of these membranes. These transport properties are correlated to the membranes’ structures derived from X-ray and microscopy techniques to determine the structure-property relationship. We successfully integrated hydrocarbon membrane MEAs with a current distribution board (CBD) to study the impact of hydrocarbon membrane on water transport in fuel cells. We have designed and fabricated various GDM with varying substrate, diffusivity and micro-porous layers (MPL) and characterized their pore structure, tortuosity and hydrophobicity. We have derived a universal chart (MacMullin number as function of wet proofing and porosity) that can be used to characterize various GDM. The abovementioned GDMs have been evaluated in operating fuel cells; their performance is correlated to various pore structure, tortuosity and hydrophobicity of the GDM. Unfortunately, determining a universal relationship between the MacMullin number and these

77 FR 28406 - Spent Fuel Transportation Risk Assessment

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-14

... Regulations (10 CFR) part 71, ``Packaging and Transportation of Radioactive Waste,'' dated January 26, 2004) for the packaging and transport of spent nuclear fuel (and other large quantities of radioactive... NUREG- 0170, ``Final Environmental Statement on the Transportation of Radioactive Material by Air and...

Thermodynamic Properties and Transport Coefficients of Nitrogen, Hydrogen and Helium Plasma Mixed with Silver Vapor

NASA Astrophysics Data System (ADS)

Zhou, Xue; Cui, Xinglei; Chen, Mo; Zhai, Guofu

2016-05-01

Species composites of Ag-N2, Ag-H2 and Ag-He plasmas in the temperature range of 3,000-20,000 K and at 1 atmospheric pressure were calculated by using the minimization of Gibbs free energy. Thermodynamic properties and transport coefficients of nitrogen, hydrogen and helium plasmas mixed with a variety of silver vapor were then calculated based on the equilibrium composites and collision integral data. The calculation procedure was verified by comparing the results obtained in this paper with the published transport coefficients on the case of pure nitrogen plasma. The influences of the silver vapor concentration on composites, thermodynamic properties and transport coefficients were finally analyzed and summarized for all the three types of plasmas. Those physical properties were important for theoretical study and numerical calculation on arc plasma generated by silver-based electrodes in those gases in sealed electromagnetic relays and contacts. supported by National Natural Science Foundation of China (Nos. 51277038 and 51307030)

Multiphase transport in polymer electrolyte membrane fuel cells

NASA Astrophysics Data System (ADS)

Gauthier, Eric D.

Polymer electrolyte membrane fuel cells (PEMFCs) enable efficient conversion of fuels to electricity. They have enormous potential due to the high energy density of the fuels they utilize (hydrogen or alcohols). Power density is a major limitation to wide-scale introduction of PEMFCs. Power density in hydrogen fuel cells is limited by accumulation of water in what is termed fuel cell `flooding.' Flooding may occur in either the gas diffusion layer (GDL) or within the flow channels of the bipolar plate. These components comprise the electrodes of the fuel cell and balance transport of reactants/products with electrical conductivity. This thesis explores the role of electrode materials in the fuel cell and examines the fundamental connection between material properties and multiphase transport processes. Water is generated at the cathode catalyst layer. As liquid water accumulates it will utilize the largest pores in the GDL to go from the catalyst layer to the flow channels. Water collects to large pores via lateral transport at the interface between the GDL and catalyst layer. We have shown that water may be collected in these large pores from several centimeters away, suggesting that we could engineer the GDL to control flooding with careful placement and distribution of large flow-directing pores. Once liquid water is in the flow channels it forms slugs that block gas flow. The slugs are pushed along the channel by a pressure gradient that is dependent on the material wettability. The permeable nature of the GDL also plays a major role in slug growth and allowing bypass of gas between adjacent channels. Direct methanol fuel cells (DMFCs) have analogous multiphase flow issues where carbon dioxide bubbles accumulate, `blinding' regions of the fuel cell. This problem is fundamentally similar to water management in hydrogen fuel cells but with a gas/liquid phase inversion. Gas bubbles move laterally through the porous GDL and emerge to form large bubbles within the

Tested Demonstrations. Gasoline Vapor: An Invisible Pollutant

ERIC Educational Resources Information Center

Stephens, Edgar R.

1977-01-01

Describes a demonstration concerning the air pollution aspects of gasoline vapor which provides an estimation of the vapor pressure of test fuel, the molecular weight of the vapor, and illustrates a method of controlling the pollution. (SL)

Ignition of Fuel Vapors Beneath Titanium Aircraft Skins Exposed to Lightning

NASA Technical Reports Server (NTRS)

Kosvic, T. C.; Helgeson, N. L.; Gerstein, M.

1971-01-01

Hot-spot and puncture ignition of fuel vapors by simulated lightning discharges was studied experimentally. The influences of skin coating, skin structure, discharge polarity, skin thickness, discharge current level, and current duration were measured and interpreted. Ignition thresholds are reported for titanium alloy constructed as sheets, sheets coated with sealants, and sandwich skins. Results indicated that the ignition threshold charge transfer for coated sheets, honeycomb, and truss skins is respectively about 200%, 400%, 800% that of bare alloy sheet of .102 cm (.040 in.)-thickness. It was found that hot-spot ignition can occur well after termination of the arc, and that sandwich materials allow ignition only if punctured.

Vapor transport deposition of antimony selenide thin film solar cells with 7.6% efficiency.

PubMed

Wen, Xixing; Chen, Chao; Lu, Shuaicheng; Li, Kanghua; Kondrotas, Rokas; Zhao, Yang; Chen, Wenhao; Gao, Liang; Wang, Chong; Zhang, Jun; Niu, Guangda; Tang, Jiang

2018-06-05

Antimony selenide is an emerging promising thin film photovoltaic material thanks to its binary composition, suitable bandgap, high absorption coefficient, inert grain boundaries and earth-abundant constituents. However, current devices produced from rapid thermal evaporation strategy suffer from low-quality film and unsatisfactory performance. Herein, we develop a vapor transport deposition technique to fabricate antimony selenide films, a technique that enables continuous and low-cost manufacturing of cadmium telluride solar cells. We improve the crystallinity of antimony selenide films and then successfully produce superstrate cadmium sulfide/antimony selenide solar cells with a certified power conversion efficiency of 7.6%, a net 2% improvement over previous 5.6% record of the same device configuration. We analyze the deep defects in antimony selenide solar cells, and find that the density of the dominant deep defects is reduced by one order of magnitude using vapor transport deposition process.

Storage, transportation and disposal system for used nuclear fuel assemblies

DOEpatents

Scaglione, John M.; Wagner, John C.

2017-01-10

An integrated storage, transportation and disposal system for used fuel assemblies is provided. The system includes a plurality of sealed canisters and a cask sized to receive the sealed canisters in side by side relationship. The plurality of sealed canisters include an internal basket structure to receive a plurality of used fuel assemblies. The internal basket structure includes a plurality of radiation-absorbing panels and a plurality of hemispherical ribs generally perpendicular to the canister sidewall. The sealed canisters are received within the cask for storage and transportation and are removed from the cask for disposal at a designated repository. The system of the present invention allows the handling of sealed canisters separately or collectively, while allowing storage and transportation of high burnup fuel and damaged fuel to the designated repository.

Preconditioning of the YSZ-NiO Fuel Cell Anode in Hydrogenous Atmospheres Containing Water Vapor.

PubMed

Vasyliv, Bogdan; Podhurska, Viktoriya; Ostash, Orest

2017-12-01

The YSZ-NiO ceramics for solid oxide fuel cells (SOFCs) anode have been investigated. A series of specimens were singly reduced in a hydrogenous atmosphere (Ar-5 vol% H 2 mixture) at 600 °C under the pressure of 0.15 MPa or subjected to 'reduction in the mixture-oxidation in air' (redox) cycling at 600 °C. The YSZ-Ni cermets formed in both treatment conditions were then aged in 'water vapor in Ar-5 vol% H 2 mixture' atmosphere at 600 °C under the pressure of 0.15 MPa. Additionally, the behaviour of the as-received material in this atmosphere was studied. It was revealed that small amount of water vapor in Ar-5 vol% H 2 mixture (water vapor pressure below 0.03 MPa) does not affect the reduction of the nickel phase in the YSZ-NiO ceramics, but causes some changes in the YSZ-Ni cermet structure. In particular, nanopore growth in tiny Ni particles takes place. At higher concentration of water vapor in the mixture (water vapor pressure above 0.03-0.05 MPa), converse changes in the kinetics of reduction occur. The best physical and mechanical properties were revealed for the material treated by redox cycling after holding at 600 °C in water depleted gas mixture. The dual effect of water vapor on nickel-zirconia anode behaviour is discussed basing on scanning electron microscopy analysis data, material electrical conductivity, and strength.

Reduced Gravity Studies of Soret Transport Effects in Liquid Fuel Combustion

NASA Technical Reports Server (NTRS)

Shaw, Benjamin D.

2004-01-01

Soret transport, which is mass transport driven by thermal gradients, can be important in practical flames as well as laboratory flames by influencing transport of low molecular weight species (e.g., monatomic and diatomic hydrogen). In addition, gas-phase Soret transport of high molecular weight fuel species that are present in practical liquid fuels (e.g., octane or methanol) can be significant in practical flames (Rosner et al., 2000; Dakhlia et al., 2002) and in high pressure droplet evaporation (Curtis and Farrell, 1992), and it has also been shown that Soret transport effects can be important in determining oxygen diffusion rates in certain classes of microgravity droplet combustion experiments (Aharon and Shaw, 1998). It is thus useful to obtain information on flames under conditions where Soret effects can be clearly observed. This research is concerned with investigating effects of Soret transport on combustion of liquid fuels, in particular liquid fuel droplets. Reduced-gravity is employed to provide an ideal (spherically-symmetrical) experimental model with which to investigate effects of Soret transport on combustion. The research will involve performing reduced-gravity experiments on combustion of liquid fuel droplets in environments where Soret effects significantly influence transport of fuel and oxygen to flame zones. Experiments will also be performed where Soret effects are not expected to be important. Droplets initially in the 0.5 to 1 mm size range will be burned. Data will be obtained on influences of Soret transport on combustion characteristics (e.g., droplet burning rates, droplet lifetimes, gas-phase extinction, and transient flame behaviors) under simplified geometrical conditions that are most amenable to theoretical modeling (i.e., spherical symmetry). The experiments will be compared with existing theoretical models as well as new models that will be developed. Normal gravity experiments will also be performed.

Fuel conservation merits of advanced turboprop transport aircraft

NASA Technical Reports Server (NTRS)

Revell, J. D.; Tullis, R. H.

1977-01-01

The advantages of a propfan powered aircraft for the commercial air transportation system were assessed by the comparison with an equivalent turbofan transport. Comparisons were accomplished on the basis of fuel utilization and operating costs, as well as aircraft weight and size. Advantages of the propfan aircraft, concerning fuel utilization and operating costs, were accomplished by considering: (1) incorporation of propfan performance and acoustic data; (2) revised mission profiles (longer design range and reduction in; and cruise speed) (3) utilization of alternate and advanced technology engines.

Transport equations in an enzymatic glucose fuel cell

NASA Astrophysics Data System (ADS)

Jariwala, Soham; Krishnamurthy, Balaji

2018-01-01

A mathematical model is developed to study the effects of convective flux and operating temperature on the performance of an enzymatic glucose fuel cell with a membrane. The model assumes isothermal operating conditions and constant feed rate of glucose. The glucose fuel cell domain is divided into five sections, with governing equations describing transport characteristics in each region, namely - anode diffusion layer, anode catalyst layer (enzyme layer), membrane, cathode catalyst layer and cathode diffusion layer. The mass transport is assumed to be one-dimensional and the governing equations are solved numerically. The effects flow rate of glucose feed on the performance of the fuel cell are studied as it contributes significantly to the convective flux. The effects of operating temperature on the performance of a glucose fuel cell are also modeled. The cell performances are compared using cell polarization curves, which were found compliant with experimental observations.

Moving beyond alternative fuel hype to decarbonize transportation

NASA Astrophysics Data System (ADS)

Melton, Noel; Axsen, Jonn; Sperling, Daniel

2016-03-01

In the past three decades, government, industry and other stakeholders have repeatedly been swept up with the ‘fuel du jour’, claiming that a particular alternative fuel vehicle (AFV) technology can succeed in replacing conventional gasoline-powered vehicles. However, AFV technologies have experienced relatively little success, with fossil fuels still accounting for about 95% of global transport energy use. Here, using the US as a case study, we conduct a media analysis to show how society’s attention has skipped among AFV types between 1980 and 2013, including methanol, natural gas, plug-in electric, hybrid electric, hydrogen and biofuels. Although our results provide no indication as to whether hype ultimately has a net positive or negative impact on AFV innovation, we offer several recommendations that governments can follow to move past hype to support significant AFV adoption and displace fossil fuel use in the transportation sector.

Fuel cell assembly with electrolyte transport

DOEpatents

Chi, Chang V.

1983-01-01

A fuel cell assembly wherein electrolyte for filling the fuel cell matrix is carried via a transport system comprising a first passage means for conveying electrolyte through a first plate and communicating with a groove in a second plate at a first point, the first and second plates together sandwiching the matrix, and second passage means acting to carry electrolyte exclusively through the second plate and communicating with the groove at a second point exclusive of the first point.

78 FR 40199 - Draft Spent Fuel Storage and Transportation Interim Staff Guidance

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-03

... NUCLEAR REGULATORY COMMISSION [NRC-2013-0140] Draft Spent Fuel Storage and Transportation Interim... Spent Fuel Storage and Transportation Interim Staff Guidance No. 24 (SFST-ISG-24), Revision 0, ``The Use of a Demonstration Program as Confirmation of Integrity for Continued Storage of High Burnup Fuel...

Alternative Fuels Data Center: Idaho Transports Mail and Reduces Emissions

Science.gov Websites

with Natural Gas Trucks Idaho Transports Mail and Reduces Emissions with Natural Gas Trucks to Natural Gas Trucks on Facebook Tweet about Alternative Fuels Data Center: Idaho Transports Mail and Reduces Emissions with Natural Gas Trucks on Twitter Bookmark Alternative Fuels Data Center: Idaho

Flashback flame arrester devices for fuel cargo tank vapor vents

NASA Technical Reports Server (NTRS)

Bjorklund, R. A.; Kushida, R. O.

1981-01-01

The flame quenching capability of four types of flame arresting devices suitable for installation on fuel cargo tank vents of marine transport vessels is evaluated. A single 30 mesh screen, a dual 20 mesh screen, a spiral wound crimped metal ribbon, and a packed bed of ballast rings were tested. Flame speed and flame penetration of the test arresters were determined. Eight fuels representative of bulk cargoes were tested. The test arresters quenched a minimum of three flashback flames from all eight fuels, with one exception: high speed ethylene flames penetrated the dual 20 mesh screen on three tests. The arresters withstood the sustained flame from a propane/air mixture for 30 minutes. None of the arresters withstood the sustained flame from an ethylene/air mixture for more than 7 minutes.

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.

Storage, transportation and disposal system for used nuclear fuel assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scaglione, John M.; Wagner, John C.

An integrated storage, transportation and disposal system for used fuel assemblies is provided. The system includes a plurality of sealed canisters and a cask sized to receive the sealed canisters in side by side relationship. The plurality of sealed canisters include an internal basket structure to receive a plurality of used fuel assemblies. The internal basket structure includes a plurality of radiation-absorbing panels and a plurality of hemispherical ribs generally perpendicular to the canister sidewall. The sealed canisters are received within the cask for storage and transportation and are removed from the cask for disposal at a designated repository. Themore » system of the present invention allows the handling of sealed canisters separately or collectively, while allowing storage and transportation of high burnup fuel and damaged fuel to the designated repository.« less

Regional analysis of renewable transportation fuels - production and consumption

NASA Astrophysics Data System (ADS)

Liu, Xiaoshuai

The transportation sector contributes more than a quarter of total U.S. greenhouse gas emissions. Replacing fossil fuels with renewable fuels can be a key solution to mitigate GHG emissions from the transportation sector. Particularly, we have focused on land-based production of renewable fuels from landfills and brownfield in the southeastern region of the United States. These so call marginal lands require no direct land-use change to avoid environmental impact and, furthermore, have rendered opportunities for carbon trading and low-carbon intensity business. The resources potential and production capacity were derived using federal and state energy databases with the aid of GIS techniques. To maximize fuels production and land-use efficiency, a scheme of co-location renewable transportation fuels for production on landfills was conducted as a case study. Results of economic modeling analysis indicate that solar panel installed on landfill sites could generate a positive return within the project duration, but the biofuel production within the landfill facility is relatively uncertain, requiring proper sizing of the onsite processing facility, economic scale of production and available tax credits. From the consumers' perspective, a life-cycle cost analysis has been conducted to determine the economic and environmental implications of different transportation choices by consumers. Without tax credits, only the hybrid electric vehicles have lifetime total costs equivalent to a conventional vehicles differing by about 1 to 7%. With tax credits, electric and hybrid electric vehicles could be affordable and attain similar lifetime total costs as compared to conventional vehicles. The dissertation research has provided policy-makers and consumers a pathway of prioritizing investment on sustainable transportation systems with a balance of environmental benefits and economic feasibility.

Analysis of Transportation Options for Commercial Spent Fuel in the U.S.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalinina, Elena; Busch, Ingrid Karin

.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage The U.S. Department of Energy (DOE) is laying the groundwork for implementing interim storage and associated transportation of spent nuclear fuel (SNF) highand associated transportation of spent nuclear fuel (SNF) and high and

Vapor crystal growth technology development: Application to cadmium telluride

NASA Technical Reports Server (NTRS)

Rosenberger, Franz; Banish, Michael; Duval, Walter M. B.

1991-01-01

Growth of bulk crystals by physical vapor transport was developed and applied to cadmium telluride. The technology makes use of effusive ampoules, in which part of the vapor contents escapes to a vacuum shroud through defined leaks during the growth process. This approach has the advantage over traditional sealed ampoule techniques that impurity vapors and excess vapor constituents are continuously removed from the vicinity of the growing crystal. Thus, growth rates are obtained routinely at magnitudes that are rather difficult to achieve in closed ampoules. Other advantages of this effusive ampoule physical vapor transport (EAPVT) technique include the predetermination of transport rates based on simple fluid dynamics and engineering considerations, and the growth of the crystal from close to congruent vapors, which largely alleviates the compositional nonuniformities resulting from buoyancy driven convective transport. After concisely reviewing earlier work on improving transport rates, nucleation control, and minimization of crystal wall interactions in vapor crystal growth, a detail account is given of the largely computer controlled EAPVT experimentation.

Performance of a Cross-Flow Humidifier with a High Flux Water Vapor Transport Membrane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahluwalia, R. K.; Wang, X.; Johnson, W. B.

Water vapor transport (WVT) flux across a composite membrane that consists of a very thin perfluorosulfonic acid (PFSA) ionomer layer sandwiched between two expanded polytetrafluoroethylene (PTFE) microporous layers is investigated. Static and dynamic tests are conducted to measure WVT flux for different composite structures; a transport model shows that the underlying individual resistances for water diffusion in the gas phase and microporous and ionomer layers and for interfacial kinetics of water uptake at the ionomer surface are equally important under different conditions. A finite-difference model is formulated to determine water transport in a full-scale (2-m2 active membrane area) planar cross-flowmore » humidifier module assembled using pleats of the optimized composite membrane. In agreement with the experimental data, the modeled WVT flux in the module increases at higher inlet relative humidity (RH) of the wet stream and at lower pressures, but the mass transfer effectiveness is higher at higher pressures. The model indicates that the WVT flux is highest under conditions that maintain the wet stream at close to 100% RH while preventing the dry stream from becoming saturated. The overall water transport is determined by the gradient in RH of the wet and dry streams but is also affected by vapor diffusion in the gas layer and the microporous layer.« less

Transportable Rayleigh/Raman lidar for aerosol and water vapor profiling

NASA Astrophysics Data System (ADS)

Congeduti, Fernando; D'Aulerio, P.; Casadio, S.; Baldetti, P.; Belardinelli, F.

2001-01-01

A nighttime operating Raman/Rayleigh/Mie lidar system for the measurement of profiles of the water vapor mixing ratio and the aerosol backscatter ratio is described. The transmitter utilizes two laser beam at 532 nm and 355 nm from a Nd:YAG pulsed laser and the receiver consists of three Newtonian telescopes. Optical fibers carry the signal to the detectors. The system, which is installed in two containers, is transportable. Data are recorded with resolutions of 75-m in altitude and 1-min in time. Water vapor profiles from 200 m above the lidar altitude up to the upper troposphere and aerosol profiles form 500 m up to the lower stratosphere were obtained also at the lowest resolution. The lidar was deployed and used in the 'Target Area of the Lago Maggiore' during the MAP-SOP international campaign. Measurements taken during that campaign are reported to show the lidar performance. Improvements of the system by employing an array of nine 50-cm diameter telescopes are planned. These should effectively enhance the lidar performance.

Study of methane fuel for subsonic transport aircraft

NASA Technical Reports Server (NTRS)

Carson, L. K.; Davis, G. W.; Versaw, E. F.; Cunnington, G. R., Jr.; Daniels, E. J.

1980-01-01

The cost and performance were defined for commercial transport using liquid methane including its fuel system and the ground facility complex required for the processing and storage of methane. A cost and performance comparison was made with Jet A and hydrogen powered aircraft of the same payload and range capability. Extensive design work was done on cryogenic fuel tanks, insulation systems as well as the fuel system itself. Three candidate fuel tank locations were evaluated, i.e., fuselage tanks, wing tanks or external pylon tanks.

Health assessment of gasoline and fuel oxygenate vapors: neurotoxicity evaluation.

PubMed

O'Callaghan, James P; Daughtrey, Wayne C; Clark, Charles R; Schreiner, Ceinwen A; White, Russell

2014-11-01

Sprague-Dawley rats were exposed via inhalation to vapor condensates of either gasoline or gasoline combined with various fuel oxygenates to assess potential neurotoxicity of evaporative emissions. Test articles included vapor condensates prepared from "baseline gasoline" (BGVC), or gasoline combined with methyl tertiary butyl ether (G/MTBE), ethyl t-butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), ethanol (G/EtOH), or t-butyl alcohol (G/TBA). Target concentrations were 0, 2000, 10,000 or 20,000mg/mg(3) and exposures were for 6h/day, 5days/week for 13weeks. The functional observation battery (FOB) with the addition of motor activity (MA) testing, hematoxylin and eosin staining of brain tissue sections, and brain regional analysis of glial fibrillary acidic protein (GFAP) were used to assess behavioral changes, traditional neuropathology and astrogliosis, respectively. FOB and MA data for all agents, except G/TBA, were negative. G/TBA behavioral effects resolved during recovery. Neuropathology was negative for all groups. Analyses of GFAP revealed increases in multiplebrain regions largely limited to males of the G/EtOH group, findings indicative of minor gliosis, most significantly in the cerebellum. Small changes (both increases and decreases) in GFAP were observed for other test agents but effects were not consistent across sex, brain region or exposure concentration. Copyright © 2014 Elsevier Inc. All rights reserved.

Health assessment of gasoline and fuel oxygenate vapors: Neurotoxicity evaluation

PubMed Central

O’Callaghan, James P.; Daughtrey, Wayne C.; Clark, Charles R.; Schreiner, Ceinwen A.; White, Russell

2016-01-01

Sprague–Dawley rats were exposed via inhalation to vapor condensates of either gasoline or gasoline combined with various fuel oxygenates to assess potential neurotoxicity of evaporative emissions. Test articles included vapor condensates prepared from “baseline gasoline” (BGVC), or gasoline combined with methyl tertiary butyl ether (G/MTBE), ethyl t-butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), ethanol (G/EtOH), or t-butyl alcohol (G/TBA). Target concentrations were 0, 2000, 10,000 or 20,000 mg/mg3 and exposures were for 6 h/day, 5 days/week for 13 weeks. The functional observation battery (FOB) with the addition of motor activity (MA) testing, hematoxylin and eosin staining of brain tissue sections, and brain regional analysis of glial fibrillary acidic protein (GFAP) were used to assess behavioral changes, traditional neuropathology and astrogliosis, respectively. FOB and MA data for all agents, except G/TBA, were negative. G/TBA behavioral effects resolved during recovery. Neuropathology was negative for all groups. Analyses of GFAP revealed increases in multiple brain regions largely limited to males of the G/EtOH group, findings indicative of minor gliosis, most significantly in the cerebellum. Small changes (both increases and decreases) in GFAP were observed for other test agents but effects were not consistent across sex, brain region or exposure concentration. PMID:24879970

Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport in Low Gravity

NASA Technical Reports Server (NTRS)

Su, Ching-Hua; Ramachandran, N.

2013-01-01

Crystals of ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, will be grown by physical vapor transport in the Material Science Research Rack (MSRR) on International Space Station (ISS). The objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the crystals grown by vapor transport as results of buoyance-driven convection and growth interface fluctuations caused by irregular fluid-flows on Earth. The investigation consists of extensive ground-based experimental and theoretical research efforts and concurrent flight experimentation. The objectives of the ground-based studies are (1) obtain the experimental data and conduct the analyses required to define the optimum growth parameters for the flight experiments, (2) perfect various characterization techniques to establish the standard procedure for material characterization, (3) quantitatively establish the characteristics of the crystals grown on Earth as a basis for subsequent comparative evaluations of the crystals grown in a low-gravity environment and (4) develop theoretical and analytical methods required for such evaluations. ZnSe and related ternary compounds have been grown by vapor transport technique with real time in-situ non-invasive monitoring techniques. The grown crystals have been characterized extensively by various techniques to correlate the grown crystal properties with the growth conditions.

Effects of repeated exposure of rats to JP-5 or JP-8 jet fuel vapor on neurobehavioral capacity and neurotransmitter levels.

PubMed

Rossi, J; Nordholm, A F; Carpenter, R L; Ritchie, G D; Malcomb, W

2001-07-20

The U.S. Naval Service is anticipating transition from the nearly exclusive use of JP-5 jet fuel to predominant use of JP-8, consistent with the primary utilization by the U.S. Army, U.S. Air Force, and the militaries of most NATO countries. To compare the relative risk of repeated exposure to JP-5 versus JP-8 vapor, groups of 32 male Sprague-Dawley rats each were exposed for 6 h/d, 5 d/wk for 6 wk (180 h) to JP-8 jet fuel vapor (1,000 +/- 10% mg/m3), IP-5 vapor (1,200 +/- 10% mg/m3), or room air control conditions. Following a 65-d rest period, rats completed 10 tests selected from the Neurobehavioral Toxicity Assessment Battery (NTAB) to evaluate changes in performance capacity. Repeated exposure to JP-5 resulted in significant effects on only one test, forelimb grip strength (FGS), while exposure to JP-8 vapor resulted in a significant difference versus controls on appetitive reinforcer approach sensitization (ARAS). Rats were further evaluated for concentrations of major neurotransmitters and metabolites in five brain regions and in the blood serum. Levels of dopamine, the dopamine metabolite dihydroxyphenylacetic acid (DOPAC), and the serotonin metabolite homovanillic acid (HVA) were significantly modulated in various brain regions, as measured 85+ d postexposure. Similarly, serum levels of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) were differentially modulated following JP-8 or JP-5 exposure. Results are compared to previously published research evaluating the neurotoxicity of repeated exposure to other hydrocarbon fuels and solvents.

Barriers to the utilization of synthetic fuels for transportation

NASA Technical Reports Server (NTRS)

Parker, H. W.; Reilly, M. J.

1981-01-01

The principal types of engines for transportation uses are reviewed and the specifications for conventional fuels are compared with specifications for synthetic fuels. Synfuel processes nearing the commercialization phase are reviewed. The barriers to using synfuels can be classified into four groups: technical, such as the uncertainty that a new engine design can satisfy the desired performance criteria; environmental, such as the risk that the engine emissions cannot meet the applicable environmental standards; economic, including the cost of using a synfuel relative to conventional transportation fuels; and market, involving market penetration by offering new engines, establishing new distribution systems and/or changing user expectations.

Evaluation of the BioVapor Model

EPA Science Inventory

The BioVapor model addresses transport and biodegradation of petroleum vapors in the subsurface. This presentation describes basic background on the nature and scientific basis of environmental transport models. It then describes a series of parameter uncertainty runs of the Bi...

A Study of Transport Airplane Crash-Resistant Fuel Systems

NASA Technical Reports Server (NTRS)

Jones, Lisa (Technical Monitor); Robertson, S. H.; Johnson, N. B.; Hall, D. S.; Rimson, I. J.

2002-01-01

This report presents the results of a study, funded by the Federal Aviation Administration (FAA), of transport airplane crash-resistant fuel system (CRFS). The report covers the historical studies related to aircraft crash fires and fuel containment concepts undertaken by the FAA, NASA, and the U.S. Army, which ultimately led to the current state of the art in CRFS technology. It describes the basic research, testing, field investigations and production efforts which have led to the highly successful military CRFS, which has saved many lives and reduced costs of accidents. Current CRFS technology used in transport category airplanes is defined and compared to the available state-of-the-art technology. The report provides information to the FAA and other government organizations which can help them plan their efforts to improve the state of crash fire protection in the transport airplane fleet. The report provides guidance to designers looking for information about CRFS design problems, analysis tools to use for product improvement, and a summary of current and proposed regulations for transport category airplane fuel systems.

Spent nuclear fuel system dynamic stability under normal conditions of transportation

DOE PAGES

Jiang, Hao; Wang, Jy-An John

2016-10-14

In a horizontal layout of a spent nuclear fuel (SNF) assembly under normal conditions of transportation (NCT), the fuel assembly’s skeleton formed by guide tubes and spacer grids is the primary load bearing structure for carrying and transferring the vibration loads within an SNF assembly. Therefore, the integrity of guide tubes and spacer grids will dictate the vibration amplitude/intensity of the fuel assembly during transport, and must be considered when designing multipurpose purpose canister (MPC) for safe SNF transport. This paper investigates the SNF assembly deformation dynamics during normal vibration mode, as well as the transient shock mode inside themore » cask during NCT. In conclusion, dynamic analyses were performed in the frequency domain to study frequency characteristic of the fuel assembly system and in the time domain to simulate the transient dynamic response of the fuel assembly.« less

Spent nuclear fuel system dynamic stability under normal conditions of transportation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Hao; Wang, Jy-An John

In a horizontal layout of a spent nuclear fuel (SNF) assembly under normal conditions of transportation (NCT), the fuel assembly’s skeleton formed by guide tubes and spacer grids is the primary load bearing structure for carrying and transferring the vibration loads within an SNF assembly. Therefore, the integrity of guide tubes and spacer grids will dictate the vibration amplitude/intensity of the fuel assembly during transport, and must be considered when designing multipurpose purpose canister (MPC) for safe SNF transport. This paper investigates the SNF assembly deformation dynamics during normal vibration mode, as well as the transient shock mode inside themore » cask during NCT. In conclusion, dynamic analyses were performed in the frequency domain to study frequency characteristic of the fuel assembly system and in the time domain to simulate the transient dynamic response of the fuel assembly.« less

Gas-pressure chemical vapor transport growth of millimeter-sized c-BAs single crystals with moderate thermal conductivity

NASA Astrophysics Data System (ADS)

Xing, Jie; Glaser, Evan R.; Song, Bai; Culbertson, James C.; Freitas, Jaime A.; Duncan, Ryan A.; Nelson, Keith A.; Chen, Gang; Ni, Ni

2018-06-01

We have grown c-BAs single crystals up to 1000 μm size by the chemical vapor transport (CVT) technique using combined As and I2 transport agents with the As:I ratio of 1:3 under gas pressures of up to 35 atm. Raman spectroscopy revealed a very sharp (˜2.4 cm-1) P1 phonon mode and an interesting splitting behavior of P1 from detailed polarization studies. Electron paramagnetic resonance (EPR) experiments revealed no evidence for EPR active growth-related defects under the experimental resolution. Finally, a moderate thermal conductivity value of ˜132 W/m-K was obtained using a transient thermal grating technique. These results suggest that although the high As gas vapor pressure environment in CVT growth can increase the transport rate of c-BAs significantly, it may not be efficient in reducing the defects and enhancing the thermal conductivity in c-BAs significantly.

Consideration of Fuel Requirements for Supersonic Transport Operation

NASA Technical Reports Server (NTRS)

Stickle, Joseph W.

1965-01-01

An analysis of the interaction of operational environment and aircraft characteristics of the supersonic transport (SST) in the areas of design-range and reserve-fuel requirements has been made. Design-range requirements are considered in relation to the effects of wind, temperature, flight-level assignment, and payload variation. An approach toward combining en route and holding reserve requirements while maintaining protection equivalent to that provided subsonic jet transport operations by the present civil air regulation en route plus holding reserves is given. This approach results in a savings in reserve fuel over that required by separate requirements.

Alternative Fuel Transportation Optimization Tool : Description, Methodology, and Demonstration Scenarios.

DOT National Transportation Integrated Search

2015-09-01

This report describes an Alternative Fuel Transportation Optimization Tool (AFTOT), developed by the U.S. Department of Transportation (DOT) Volpe National Transportation Systems Center (Volpe) in support of the Federal Aviation Administration (FAA)....

Carbon agent chemical vapor transport growth of Ga2O3 crystal

NASA Astrophysics Data System (ADS)

Jie, Su; Tong, Liu; Jingming, Liu; Jun, Yang; Guiying, Shen; Yongbiao, Bai; Zhiyuan, Dong; Youwen, Zhao

2016-10-01

Beta-type gallium oxide (β-Ga2O3) is a new attractive material for optoelectronic devices. Different methods had been tried to grow high quality β-Ga2O3 crystals. In this work, crystal growth of Ga2O3 has been carried out by chemical vapor transport (CVT) method in a closed quartz tube using C as transport agent and sapphire wafer as seed. The CVT mass flux has been analyzed by theoretical calculations based on equilibrium thermodynamics and 1D diffusional mass transport. The crystal growth experimental results are in agreement with the theoretical predictions. Influence factors of Ga2O3 crystal growth, such as temperature distribution, amount of C as transport agent used, have also been discussed. Structural (XRD) and optical (Raman spectroscopy, photoluminescence spectrum) properties of the CVT-Ga2O3 crystal are presented. Project supported by the National Natural Science Foundation of China (Nos. 61474104, 61504131).

Fuel processor for fuel cell power system

DOEpatents

Vanderborgh, Nicholas E.; Springer, Thomas E.; Huff, James R.

1987-01-01

A catalytic organic fuel processing apparatus, which can be used in a fuel cell power system, contains within a housing a catalyst chamber, a variable speed fan, and a combustion chamber. Vaporized organic fuel is circulated by the fan past the combustion chamber with which it is in indirect heat exchange relationship. The heated vaporized organic fuel enters a catalyst bed where it is converted into a desired product such as hydrogen needed to power the fuel cell. During periods of high demand, air is injected upstream of the combustion chamber and organic fuel injection means to burn with some of the organic fuel on the outside of the combustion chamber, and thus be in direct heat exchange relation with the organic fuel going into the catalyst bed.

Biomass Conversion to Produce Hydrocarbon Liquid Fuel Via Hot-vapor Filtered Fast Pyrolysis and Catalytic Hydrotreating.

PubMed

Wang, Huamin; Elliott, Douglas C; French, Richard J; Deutch, Steve; Iisa, Kristiina

2016-12-25

Lignocellulosic biomass conversion to produce biofuels has received significant attention because of the quest for a replacement for fossil fuels. Among the various thermochemical and biochemical routes, fast pyrolysis followed by catalytic hydrotreating is considered to be a promising near-term opportunity. This paper reports on experimental methods used 1) at the National Renewable Energy Laboratory (NREL) for fast pyrolysis of lignocellulosic biomass to produce bio-oils in a fluidized-bed reactor and 2) at Pacific Northwest National Laboratory (PNNL) for catalytic hydrotreating of bio-oils in a two-stage, fixed-bed, continuous-flow catalytic reactor. The configurations of the reactor systems, the operating procedures, and the processing and analysis of feedstocks, bio-oils, and biofuels are described in detail in this paper. We also demonstrate hot-vapor filtration during fast pyrolysis to remove fine char particles and inorganic contaminants from bio-oil. Representative results showed successful conversion of biomass feedstocks to fuel-range hydrocarbon biofuels and, specifically, the effect of hot-vapor filtration on bio-oil production and upgrading. The protocols provided in this report could help to generate rigorous and reliable data for biomass pyrolysis and bio-oil hydrotreating research.

Biomass Conversion to Produce Hydrocarbon Liquid Fuel Via Hot-vapor Filtered Fast Pyrolysis and Catalytic Hydrotreating

PubMed Central

Wang, Huamin; Elliott, Douglas C.; French, Richard J.; Deutch, Steve; Iisa, Kristiina

2016-01-01

Lignocellulosic biomass conversion to produce biofuels has received significant attention because of the quest for a replacement for fossil fuels. Among the various thermochemical and biochemical routes, fast pyrolysis followed by catalytic hydrotreating is considered to be a promising near-term opportunity. This paper reports on experimental methods used 1) at the National Renewable Energy Laboratory (NREL) for fast pyrolysis of lignocellulosic biomass to produce bio-oils in a fluidized-bed reactor and 2) at Pacific Northwest National Laboratory (PNNL) for catalytic hydrotreating of bio-oils in a two-stage, fixed-bed, continuous-flow catalytic reactor. The configurations of the reactor systems, the operating procedures, and the processing and analysis of feedstocks, bio-oils, and biofuels are described in detail in this paper. We also demonstrate hot-vapor filtration during fast pyrolysis to remove fine char particles and inorganic contaminants from bio-oil. Representative results showed successful conversion of biomass feedstocks to fuel-range hydrocarbon biofuels and, specifically, the effect of hot-vapor filtration on bio-oil production and upgrading. The protocols provided in this report could help to generate rigorous and reliable data for biomass pyrolysis and bio-oil hydrotreating research. PMID:28060311

Synthetic fuels for ground transportation with special emphasis on hydrogen

NASA Technical Reports Server (NTRS)

Singh, J. J.

1975-01-01

The role of various synthetic fuels, for ground transportation in the United States, was examined for the near term (by 1985) and the longer term applications (1985-2000 and beyond 2000). Feasible options include synthetic oil, methanol, electric propulsion, and hydrogen. It is concluded that (1) the competition during the next 50 years will be for the fuels of all types, rather than among the fuels; (2) extensive domestic oil and gas exploration should be initiated concurrent with the development of several alternate fuels and related ancillaries; and (3) hydrogen, as an automotive fuel, seems to be equivalent to gasoline for optimum fuel to air mixtures. As a pollution free, high energy density fuel, hydrogen deserves consideration as the logical replacement for the hydrocarbons. Several research and development requirements, essential for the implementation of hydrogen economy for ground transportation, were identified. Extensive engineering development and testing activities should be initiated to establish hydrogen as the future automotive fuel, followed by demonstration projects and concerted efforts at public education.

Vapor Transport Within the Thermal Diffusion Cloud Chamber

NASA Technical Reports Server (NTRS)

Ferguson, Frank T.; Heist, Richard H.; Nuth, Joseph A., III

2000-01-01

A review of the equations used to determine the 1-D vapor transport in the thermal diffusion cloud chamber (TDCC) is presented. These equations closely follow those of the classical Stefan tube problem in which there is transport of a volatile species through a noncondensible, carrier gas. In both cases, the very plausible assumption is made that the background gas is stagnant. Unfortunately, this assumption results in a convective flux which is inconsistent with the momentum and continuity equations for both systems. The approximation permits derivation of an analytical solution for the concentration profile in the Stefan tube, but there is no computational advantage in the case of the TDCC. Furthermore, the degree of supersaturation is a sensitive function of the concentration profile in the TD CC and the stagnant background gas approximation can make a dramatic difference in the calculated supersaturation. In this work, the equations typically used with a TDCC are compared with very general transport equations describing the 1-D diffusion of the volatile species. Whereas no pressure dependence is predicted with the typical equations, a strong pressure dependence is present with the more general equations given in this work. The predicted behavior is consistent with observations in diffusion cloud experiments. It appears that the new equations may account for much of the pressure dependence noted in TDCC experiments, but a comparison between the new equations and previously obtained experimental data are needed for verification.

Electricity as Transportation ``Fuel''

NASA Astrophysics Data System (ADS)

Tamor, Michael

2013-04-01

The personal automobile is a surprisingly efficient device, but its place in a sustainable transportation future hinges on its ability use a sustainable fuel. While electricity is widely expected to be such a ``fuel,'' the viability of electric vehicles rests on the validity of three assumptions. First, that the emissions from generation will be significantly lower than those from competing chemical fuels whether `renewable' or fossil. Second, that advances in battery technology will deliver adequate range and durability at an affordable cost. Third, that most customers will accept any functional limitations intrinsic to electrochemical energy storage. While the first two are subjects of active research and vigorous policy debate, the third is treated virtually as a given. Popular statements to the effect that ``because 70% of all daily travel is accomplished in less than 100 miles, mass deployment of 100 mile EVs will electrify 70% of all travel'' are based on collections of one-day travel reports such as the National Household Travel Survey, and so effectively ignore the complexities of individual needs. We have analyzed the day-to-day variations of individual vehicle usage in multiple regions and draw very different conclusions. Most significant is that limited EV range results in a level of inconvenience that is likely to be unacceptable to the vast majority of vehicle owners, and for those who would accept that inconvenience, battery costs must be absurdly low to achieve any economic payback. In contrast, the plug-in hybrid (PHEV) does not suffer range limitations and delivers economic payback for most users at realistic battery costs. More importantly, these findings appear to be universal in developed nations, with labor market population density being a powerful predictor of personal vehicle usage. This ``scalable city'' hypothesis may prove to a powerful predictor of the evolution of transportation in the large cities of the developing world.

Potential of hydrogen fuel for future air transportation systems.

NASA Technical Reports Server (NTRS)

Small, W. J.; Fetterman, D. E.; Bonner, T. F., Jr.

1973-01-01

Recent studies have shown that hydrogen fuel can yield spectacular improvements in aircraft performance in addition to its more widely discussed environmental advantages. The characteristics of subsonic, supersonic, and hypersonic transport aircraft using hydrogen fuel are discussed, and their performance and environmental impact are compared to that of similar aircraft using conventional fuel. The possibilities of developing hydrogen-fueled supersonic and hypersonic vehicles with sonic boom levels acceptable for overland flight are also explored.

Rapid methods for radionuclide contaminant transport in nuclear fuel cycle simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huff, Kathryn

Here, nuclear fuel cycle and nuclear waste disposal decisions are technologically coupled. However, current nuclear fuel cycle simulators lack dynamic repository performance analysis due to the computational burden of high-fidelity hydrolgic contaminant transport models. The Cyder disposal environment and repository module was developed to fill this gap. It implements medium-fidelity hydrologic radionuclide transport models to support assessment appropriate for fuel cycle simulation in the Cyclus fuel cycle simulator. Rapid modeling of hundreds of discrete waste packages in a geologic environment is enabled within this module by a suite of four closed form models for advective, dispersive, coupled, and idealized con-more » taminant transport: a Degradation Rate model, a Mixed Cell model, a Lumped Parameter model, and a 1-D Permeable Porous Medium model. A summary of the Cyder module, its timestepping algorithm, and the mathematical models implemented within it are presented. Additionally, parametric demonstrations simulations performed with Cyder are presented and shown to demonstrate functional agreement with parametric simulations conducted in a standalone hydrologic transport model, the Clay Generic Disposal System Model developed by the Used Fuel Disposition Campaign Department of Energy Office of Nuclear Energy.« less

Rapid methods for radionuclide contaminant transport in nuclear fuel cycle simulation

DOE PAGES

Huff, Kathryn

2017-08-01

Here, nuclear fuel cycle and nuclear waste disposal decisions are technologically coupled. However, current nuclear fuel cycle simulators lack dynamic repository performance analysis due to the computational burden of high-fidelity hydrolgic contaminant transport models. The Cyder disposal environment and repository module was developed to fill this gap. It implements medium-fidelity hydrologic radionuclide transport models to support assessment appropriate for fuel cycle simulation in the Cyclus fuel cycle simulator. Rapid modeling of hundreds of discrete waste packages in a geologic environment is enabled within this module by a suite of four closed form models for advective, dispersive, coupled, and idealized con-more » taminant transport: a Degradation Rate model, a Mixed Cell model, a Lumped Parameter model, and a 1-D Permeable Porous Medium model. A summary of the Cyder module, its timestepping algorithm, and the mathematical models implemented within it are presented. Additionally, parametric demonstrations simulations performed with Cyder are presented and shown to demonstrate functional agreement with parametric simulations conducted in a standalone hydrologic transport model, the Clay Generic Disposal System Model developed by the Used Fuel Disposition Campaign Department of Energy Office of Nuclear Energy.« less

Study of fuel systems for LH2-fueled subsonic transport aircraft, volume 1

NASA Technical Reports Server (NTRS)

Brewer, G. D.; Morris, R. E.; Davis, G. W.; Versaw, E. F.; Cunnington, G. R., Jr.; Riple, J. C.; Baerst, C. F.; Garmong, G.

1978-01-01

Several engine concepts examined to determine a preferred design which most effectively exploits the characteristics of hydrogen fuel in aircraft tanks received major emphasis. Many candidate designs of tank structure and cryogenic insulation systems were evaluated. Designs of all major elements of the aircraft fuel system including pumps, lines, valves, regulators, and heat exchangers received attention. Selected designs of boost pumps to be mounted in the LH2 tanks, and of a high pressure pump to be mounted on the engine were defined. A final design of LH2-fueled transport aircraft was established which incorporates a preferred design of fuel system. That aircraft was then compared with a conventionally fueled counterpart designed to equivalent technology standards.

Summary report on transportation of nuclear fuel materials in Japan : transportation infrastructure, threats identified in open literature, and physical protection regulations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cochran, John Russell; Ouchi, Yuichiro; Furaus, James Phillip

2008-03-01

This report summarizes the results of three detailed studies of the physical protection systems for the protection of nuclear materials transport in Japan, with an emphasis on the transportation of mixed oxide fuel materials1. The Japanese infrastructure for transporting nuclear fuel materials is addressed in the first section. The second section of this report presents a summary of baseline data from the open literature on the threats of sabotage and theft during the transport of nuclear fuel materials in Japan. The third section summarizes a review of current International Atomic Energy Agency, Japanese and United States guidelines and regulations concerningmore » the physical protection for the transportation of nuclear fuel materials.« less

A ``NEW'' Solid-Core Reactor Fuel Form that Maximizes the Performance of Nuclear Thermal and Electric Rockets

NASA Astrophysics Data System (ADS)

Rom, Frank E.; Finnegan, Patrick M.

1994-07-01

The ``NEW'' solid-core fuel form is the old Vapor Transport (VT) fuel pin investigated at NASA about 30 years ago. It is simply a tube sealed at both ends partially filled with UO2. During operation the UO2 forms an annular layer on the inside of the tube by vaporization and condensation. This form is an ideal structure for overall strength and retention of fission products. All of the structural material lies between the fuel (including fission products) and the reactor coolant. The isothermal inside fuel surface temperature that results from the vaporization and condensation of fuel during operation eliminates hotspots, significantly increasing the design fuel pin surface temperature. For NTP, W-UO2 fuel pins yield higher operating temperatures than for other fuel forms, because W has about a ten-fold lower vaporization rate compared to any other known material. The use of perigee propulsion using W-UO2 fuel pins can result in a more than ten-fold reduction in reactor power. Lower reactor power, together with zero fission product release potential, and the simplicity of fabrication of VT fuel pins should greatly simplify and reduce the cost of development of NTP. For NEP, VT fuel pins can increase fast neutron spectrum reactor life with no fission product release. Thermal spectrum NEP reactors using W184 or Mo VT fuel pins, with only small amounts of high neutron absorbing additives, offer benefits because of much lower fissionable fuel requirements. The VT fuel pin has application to commercial power reactors with similar benefits.

Alternative Fuels Data Center: Mississippi Transportation Data for

Science.gov Websites

with other local stakeholders. Gasoline Diesel Natural Gas Transportation Fuel Consumption Source Renewable Power Plants 0 Renewable Power Plant Capacity (nameplate, MW) 0 Source: BioFuels Atlas from the $2.19/GGE $2.50/gallon $2.50/GGE Diesel $2.61/gallon $2.35/GGE $2.96/gallon $2.66/GGE Source: Average

Alternative Fuels Data Center: Virginia Transportation Corporation Runs

Science.gov Websites

Vehicle Haulers in Alabama on Natural Gas Virginia Transportation Corporation Runs Vehicle Haulers in Alabama on Natural Gas to someone by E-mail Share Alternative Fuels Data Center: Virginia Transportation Corporation Runs Vehicle Haulers in Alabama on Natural Gas on Facebook Tweet about Alternative

Alternative Fuels Data Center: Pittsburgh Livery Company Transports

Science.gov Websites

Customers in Alternative Fuel VehiclesA> Pittsburgh Livery Company Transports Customers in hybrid, propane, and natural gas vehicles to transport customers. For information about this project Television Related Videos Photo of a car Electric Vehicles Charge up at State Parks in West Virginia Dec. 9

Crystal growth of ZnSe and related ternary compound semiconductors by physical vapor transport

NASA Technical Reports Server (NTRS)

Su, Ching-Hua

1993-01-01

The materials to be investigated are ZnSe and related ternary semiconducting alloys (e.g., ZnS(x)Se(1-x), ZnTe(x)Se(1-x), and Zn(1-x)Cd(x)Se). These materials are useful for opto-electronic applications such as high efficient light emitting diodes and low power threshold and high temperature lasers in the blue-green region of the visible spectrum. The recent demonstration of its optical bistable properties also makes ZnSe a possible candidate material for digital optical computers. The investigation consists of an extensive ground-based study followed by flight experimentation, and involves both experimental and theoretical work. The objectives of the ground-based work are to establish the characteristics of the crystals grown on Earth as a basis for subsequent comparative evaluations of the crystals grown in a low gravity environment and to obtain the experimental data and perform the analyses required to define the optimum parameters for the flight experiments. During the six months of the Preliminary Definition Phase, the research efforts were concentrated on the binary compound ZnSe - the purification of starting materials of Se by zone refining, the synthesis of ZnSe starting materials, the heat treatments of the starting materials, the vapor transport rate measurements, the vapor partial pressure measurements of ZnSe, the crystal growth of ZnSe by physical vapor transport, and various characterization on the grown ZnSe crystals.

Reduction of degradation in vapor phase transported InP/InGaAsP mushroom stripe lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jung, H.; Burkhardt, E.G.; Pfister, W.

1988-10-03

The rapid degradation rate generally observed in InP/InGaAsP mushroom stripe lasers can be considerably decreased by regrowing the open sidewalls of the active stripe with low-doped InP in a second epitaxial step using the hydride vapor phase transport technique. This technique does not change the fundamental laser parameters like light-current and current-voltage characteristics. Because of this drastic reduction in degradation, the vapor phase epitaxy regrown InP/InGaAsP mushroom laser seems to be an interesting candidate for application in optical communication.

Exergy analysis of a solid oxide fuel cell micropowerplant

NASA Astrophysics Data System (ADS)

Hotz, Nico; Senn, Stephan M.; Poulikakos, Dimos

In this paper, an analytical model of a micro solid oxide fuel cell (SOFC) system fed by butane is introduced and analyzed in order to optimize its exergetic efficiency. The micro SOFC system is equipped with a partial oxidation (POX) reformer, a vaporizer, two pre-heaters, and a post-combustor. A one-dimensional (1D) polarization model of the SOFC is used to examine the effects of concentration overpotentials, activation overpotentials, and ohmic resistances on cell performance. This 1D polarization model is extended in this study to a two-dimensional (2D) fuel cell model considering convective mass and heat transport along the fuel cell channel and from the fuel cell to the environment. The influence of significant operational parameters on the exergetic efficiency of the micro SOFC system is discussed. The present study shows the importance of an exergy analysis of the fuel cell as part of an entire thermodynamic system (transportable micropowerplant) generating electric power.

Gene expression profiles in the rat central nervous system induced by JP-8 jet fuel vapor exposure.

PubMed

Lin, Baochuan; Ritchie, Glenn D; Rossi, John; Pancrazio, Joseph J

2004-06-17

Jet propulsion fuel-8 (JP-8) is the predominant fuel for military land vehicles and aircraft used in the US and NATO. Occupational exposure to jet fuel in military personnel has raised concern for the health risk associated with such exposure in the Department of Defense. Clinical studies of humans chronically exposed to jet fuel have suggested both neurotoxicity and neurobehavioral deficits. We utilized rat neurobiology U34 array to measure gene expression changes in whole brain tissue of rats exposed repeatedly to JP-8, under conditions that simulated possible occupational exposure (6 h/day for 91 days) to JP-8 vapor at 250, 500, and 1000 mg/m(3), respectively. Our studies revealed that the gene expression changes of exposure groups can be divided into two main categories according to their functions: (1). neurotransmitter signaling pathways; and (2). stress response. The implications of these gene expression changes are discussed.

Polymer electrolyte fuel cells for transportation applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Springer, T.E.; Wilson, M.S.; Garzon, F.H.

1993-01-01

The application of the polymer electrolyte fuel cell (PEFC) as a primary power source in electric vehicles has received incrming attention during the last few years. This increased attention has been fueled by a combination of significant technical advances in this field and by the initiation of some projects for the demonstration of a complete, PEFC-based power system in a bus or in a passenger car. Such demonstration pretieds reflect an increased faith of industry in the potential of this technology for transportation applications, or, at least, in the need for a detailed evaluation of this potential Nevertheless, large scalemore » transportation applications of PEFCs requim a continued concerted effort of research on catalysis, materials and components, combined with the engineering efforts addressing the complete power system. This is required to achieve cost effective, highly performing PEFC stack and power system. We describe in this contribution some recent results of work performed within the Core Research PEFC Program at Los Alamos National Laboratory, which has addressed transportation applications of PEFCs.« less

Polymer electrolyte fuel cells for transportation applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Springer, T.E.; Wilson, M.S.; Garzon, F.H.

1993-03-01

The application of the polymer electrolyte fuel cell (PEFC) as a primary power source in electric vehicles has received incrming attention during the last few years. This increased attention has been fueled by a combination of significant technical advances in this field and by the initiation of some projects for the demonstration of a complete, PEFC-based power system in a bus or in a passenger car. Such demonstration pretieds reflect an increased faith of industry in the potential of this technology for transportation applications, or, at least, in the need for a detailed evaluation of this potential Nevertheless, large scalemore » transportation applications of PEFCs requim a continued concerted effort of research on catalysis, materials and components, combined with the engineering efforts addressing the complete power system. This is required to achieve cost effective, highly performing PEFC stack and power system. We describe in this contribution some recent results of work performed within the Core Research PEFC Program at Los Alamos National Laboratory, which has addressed transportation applications of PEFCs.« less

Multi-Scale Computational Analyses of JP-8 Fuel Droplets and Vapors in Human Respiratory Airway Models

DTIC Science & Technology

2007-10-31

equation of ultrafine particles , or (JP-8) fuel vapor, whose dominant radial transfer mechanisms are Brownian motion and turbulent dispersion is given in...Deposition of ultrafine particles at carinal ridges of the upper bronchial airways. Aerosol Science and Technology 38, 991-1000. Comer, J.K...from studies of ultrafine particles . Environmental Health Perspectives 113, 823-839. Ritchie, G., Still, K., Rossi III, J., Bekkedal, M., Bobb, A. and

BioVapor Model Evaluation (St. Louis, MO)

EPA Science Inventory

The BioVapor model addresses transport and biodegradation of petroleum vapors in the subsurface. This presentation describes basic background on the nature and scientific basis of environmental transport models. It then describes a series of parameter uncertainty runs of the Bi...

The Effect of Cirrus Clouds on Water Vapor Transport in the Upper Troposphere and Lower Stratosphere

NASA Astrophysics Data System (ADS)

Lei, L.; McCormick, M. P.; Anderson, J.

2017-12-01

Water vapor plays an important role in the Earth's radiation budget and stratospheric chemistry. It is widely accepted that a large percentage of water vapor entering the stratosphere travels through the tropical tropopause and is dehydrated by the cold tropopause temperature. The vertical transport of water vapor is also affected by the radiative effects of cirrus clouds in the tropical tropopause layer. This latter effect of cirrus clouds was investigated in this research. The work focuses on the tropical and mid-latitude region (50N-50S). Water vapor data from the Microwave Limb Sounder (MLS) and cirrus cloud data from the Cloud-Aerosol Lidar and Infrared pathfinder Satellite Observation (CALIPSO) instruments were used to investigate the relationship between the water vapor and the occurrence of cirrus cloud. A 10-degree in longitude by 10-degree in latitude resolution was chosen to bin the MLS and CALIPSO data. The result shows that the maximum water vapor in the upper troposphere (below 146 hPa) is matched very well with the highest frequency of cirrus cloud occurrences. Maximum water vapor in the lower stratosphere (100 hPa) is partly matched with the maximum cirrus cloud occurrence in the summer time. The National Oceanic and Atmospheric Administration Interpolated Outgoing Longwave Radiation data and NCEP-DOE Reanalysis 2 wind data were used also to investigate the relationship between the water vapor entering the stratosphere, deep convection, and wind. Results show that maximum water vapor at 100 hPa coincides with the northern hemisphere summer-time anticyclone. The effects from both single-layer cirrus clouds and cirrus clouds above the anvil top on the water vapor entering the stratosphere were also studied and will be presented.

DSMC simulations of vapor transport toward development of the lithium vapor box divertor concept

NASA Astrophysics Data System (ADS)

Jagoe, Christopher; Schwartz, Jacob; Goldston, Robert

2016-10-01

The lithium vapor divertor box concept attempts to achieve volumetric dissipation of the high heat efflux from a fusion power system. The vapor extracts the heat of the incoming plasma by ionization and radiation, while remaining localized in the vapor box due to differential pumping based on rapid condensation. Preliminary calculations with lithium vapor at densities appropriate for an NSTX-U-scale machine give Knudsen numbers between 0.01 and 1, outside both the range of continuum fluid dynamics and of collisionless Monte Carlo. The direct-simulation Monte Carlo (DSMC) method, however, can simulate rarefied gas flows in this regime. Using the solver contained in the OpenFOAM package, pressure-driven flows of water vapor will be analyzed. The use of water vapor in the relevant range of Knudsen number allows for a flexible similarity experiment to verify the reliability of the code before moving to tests with lithium. The simulation geometry consists of chains of boxes on a temperature gradient, connected by slots with widths that are a representative fraction of the dimensions of the box. We expect choked flow, sonic shocks, and order-of-magnitude pressure and density drops from box to box, but this expectation will be tested in the simulation and then experiment. This work is supported by the Princeton Environmental Institute.

Biomass conversion to produce hydrocarbon liquid fuel via hot-vapor filtered fast pyrolysis and catalytic hydrotreating

DOE PAGES

Wang, Huamin; Elliott, Douglas C.; French, Richard J.; ...

2016-12-25

Lignocellulosic biomass conversion to produce biofuels has received significant attention because of the quest for a replacement for fossil fuels. Among the various thermochemical and biochemical routes, fast pyrolysis followed by catalytic hydrotreating is considered to be a promising near-term opportunity. This paper reports on experimental methods used 1) at the National Renewable Energy Laboratory (NREL) for fast pyrolysis of lignocellulosic biomass to produce bio-oils in a fluidized-bed reactor and 2) at Pacific Northwest National Laboratory (PNNL) for catalytic hydrotreating of bio-oils in a two-stage, fixed-bed, continuous-flow catalytic reactor. The configurations of the reactor systems, the operating procedures, and themore » processing and analysis of feedstocks, bio-oils, and biofuels are described in detail in this paper. We also demonstrate hot-vapor filtration during fast pyrolysis to remove fine char particles and inorganic contaminants from bio-oil. Representative results showed successful conversion of biomass feedstocks to fuel-range hydrocarbon biofuels and, specifically, the effect of hot-vapor filtration on bio-oil production and upgrading. As a result, the protocols provided in this report could help to generate rigorous and reliable data for biomass pyrolysis and bio-oil hydrotreating research.« less

Biomass conversion to produce hydrocarbon liquid fuel via hot-vapor filtered fast pyrolysis and catalytic hydrotreating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Huamin; Elliott, Douglas C.; French, Richard J.

Lignocellulosic biomass conversion to produce biofuels has received significant attention because of the quest for a replacement for fossil fuels. Among the various thermochemical and biochemical routes, fast pyrolysis followed by catalytic hydrotreating is considered to be a promising near-term opportunity. This paper reports on experimental methods used 1) at the National Renewable Energy Laboratory (NREL) for fast pyrolysis of lignocellulosic biomass to produce bio-oils in a fluidized-bed reactor and 2) at Pacific Northwest National Laboratory (PNNL) for catalytic hydrotreating of bio-oils in a two-stage, fixed-bed, continuous-flow catalytic reactor. The configurations of the reactor systems, the operating procedures, and themore » processing and analysis of feedstocks, bio-oils, and biofuels are described in detail in this paper. We also demonstrate hot-vapor filtration during fast pyrolysis to remove fine char particles and inorganic contaminants from bio-oil. Representative results showed successful conversion of biomass feedstocks to fuel-range hydrocarbon biofuels and, specifically, the effect of hot-vapor filtration on bio-oil production and upgrading. As a result, the protocols provided in this report could help to generate rigorous and reliable data for biomass pyrolysis and bio-oil hydrotreating research.« less

Using "CONNected objECT (CONNECT)" Algorithm to Explore Intense Global Water Vapor Transport to Investigate Impacts of Climate Variability and Change

NASA Astrophysics Data System (ADS)

Kawzenuk, B.; Sellars, S. L.; Nguyen, P.; Ralph, F. M.; Sorooshian, S.

2017-12-01

The CONNected objECT (CONNECT) algorithm is applied to Integrated Water Vapor Transport (IVT) data from the NASA's Modern-Era Retrospective Analysis for Research and Applications - Version 2 reanalysis product for the period 1980 to 2016 to study water vapor transport globally. The algorithm generates life-cycle records as statistical objects for the time and space location of the evolving strong vapor transport events. Global statistics are presented and used to investigate how climate variability impacts the events' location and frequency. Results show distinct water vapor object frequency and seasonal peaks during NH and SH Winter. Moreover, a positive linear trend in the annual number of objects is reported, increasing by 3.58 objects year-over-year (with 95% confidence, +/- 1.39). In addition, we show five distinct regions where these events typically exist (southeastern United States, eastern China, South Pacific south of 25°S, eastern South America and off the southern tip of South Africa), and where they rarely exist (eastern South Pacific Ocean and central southern Atlantic Ocean between 5°N-25°S). In addition, the event frequency and geographical location are also shown to be related to the Arctic Oscillation, Pacific North American Pattern, and the Quasi-Biennial Oscillation.

Alternative Fuels in Transportation : Workforce needs and opportunities in support of reducing reliance on petroleum fuels

DOT National Transportation Integrated Search

2016-01-01

An overreliance on foreign oil and the negative impacts of using petroleum fuels on the worlds climate have prompted energy policies that support the diversification of transport fuels and aggressive work to transition to non-petroleum options. Th...

Effects of Atmospheric Conditions and the Land/Atmospheric Interface on Transport of Chemical Vapors from Subsurface Sources

NASA Astrophysics Data System (ADS)

Rice, A. K.; Smits, K. M.; Cihan, A.; Howington, S. E.; Illangasekare, T. H.

2013-12-01

Understanding the movement of chemical vapors and gas through variably saturated soil subjected to atmospheric thermal and mass flux boundary conditions at the land/atmospheric interface is important to many applications, including landmine detection, methane leakage during natural gas production from shale and CO2 leakage from deep geologic storage. New, advanced technologies exist to sense chemical signatures and gas leakage at the land/atmosphere interface, but interpretation of sensor signals remains a challenge. Chemical vapors are subject to numerous interactions while migrating through the soil environment, masking source conditions. The process governing movement of gases through porous media is often assumed to be Fickian diffusion through the air phase with minimal quantification of other processes, such as convective gas flow and temporal or spatial variation in soil moisture. Vapor migration is affected by atmospheric conditions (e.g. humidity, temperature, wind velocity), soil thermal and hydraulic properties and contaminant properties, all of which are physically and thermodynamically coupled. The complex coupling of two drastically different flow regimes in the subsurface and atmosphere is commonly ignored in modeling efforts, or simplifying assumptions are made to treat the systems as de-coupled. Experimental data under controlled laboratory settings are lacking to refine the theory for proper coupling and complex treatment of vapor migration through porous media in conversation with atmospheric flow and climate variations. Improving fundamental understanding and accurate quantification of these processes is not feasible in field settings due to lack of controlled initial and boundary conditions and inability to fully characterize the subsurface at all relevant scales. The goal of this work is to understand the influence of changes in atmospheric conditions to transport of vapors through variably saturated soil. We have developed a tank apparatus

An assessment and comparison of fuel cells for transportation applications

NASA Astrophysics Data System (ADS)

Krumpelt, M.; Christianson, C. C.

1989-09-01

Fuel cells offer the potential of a clean, efficient power source for buses, cars, and other transportation applications. When the fuel cell is run on methanol, refueling would be as rapid as with gasoline-powered internal combustion engines, providing a virtually unlimited range while still maintaining the smooth and quiet acceleration that is typical for electric vehicles. The advantages and disadvantages of five types of fuel cells are reviewed and analyzed for a transportation application: alkaline, phosphoric acid, proton exchange membrane, molten carbonate, and solid oxide. The status of each technology is discussed, system designs are reviewed, and preliminary comparisons of power densities, start-up times, and dynamic response capabilities are made. To test the concept, a fuel cell/battery powered urban bus appears to be a good first step that can be realized today with phosphoric acid cells. In the longer term, the proton exchange membrane and solid oxide fuel cells appear to be superior.

Comparative analyses of spent nuclear fuel transport modal options: Transport options under existing site constraints

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brentlinger, L.A.; Hofmann, P.L.; Peterson, R.W.

1989-08-01

The movement of nuclear waste can be accomplished by various transport modal options involving different types of vehicles, transport casks, transport routes, and intermediate intermodal transfer facilities. A series of systems studies are required to evaluate modal/intermodal spent fuel transportation options in a consistent fashion. This report provides total life-cycle cost and life-cycle dose estimates for a series of transport modal options under existing site constraints. 14 refs., 7 figs., 28 tabs.

Hydrogen for the subsonic transport. [aircraft design and fuel requirements

NASA Technical Reports Server (NTRS)

Korycinski, P. F.; Snow, D. B.

1975-01-01

Relations between air travel and fuel requirements are examined. Alternate fuels considered in connection with problems related to a diminishing supply of petroleum include synthetic jet fuel, methane, and hydrogen. A cruise flight of a subsonic aircraft on a hydrogen-fueled jet engine was demonstrated in 1957. However, more development work is required to provide a sound engineering base for a complete air transportation system using hydrogen as fuel. Aircraft designs for alternate fuels are discussed, giving attention to hydrogen-related technology already available and new developments which are needed.

Water vapor diffusion membranes, 2

NASA Technical Reports Server (NTRS)

Holland, F. F.; Klein, E.; Smith, J. K.; Eyer, C.

1976-01-01

Transport mechanisms were investigated for the three different types of water vapor diffusion membranes. Membranes representing porous wetting and porous nonwetting structures as well as dense diffusive membrane structures were investigated for water permeation rate as a function of: (1) temperature, (2) solids composition in solution, and (3) such hydrodynamic parameters as sweep gas flow rate, solution flow rate and cell geometry. These properties were measured using nitrogen sweep gas to collect the effluent. In addition, the chemical stability to chromic acid-stabilized urine was measured for several of each type of membrane. A technology based on the mechanism of vapor transport was developed, whereby the vapor diffusion rates and relative susceptibility of membranes to fouling and failure could be projected for long-term vapor recovery trials using natural chromic acid-stabilized urine.

FY 2012 USED FUEL DISPOSITION CAMPAIGN TRANSPORTATION TASK REPORT ON INL EFFORTS SUPPORTING THE MODERATOR EXCLUSION CONCEPT AND STANDARDIZED TRANSPORTATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

D. K. Morton

2012-08-01

Following the defunding of the Yucca Mountain Project, it is reasonable to assume that commercial used fuel will remain in storage for a longer time period than initially assumed. Previous transportation task work in FY 2011, under the Department of Energy’s Office of Nuclear Energy, Used Fuel Disposition Campaign, proposed an alternative for safely transporting used fuel regardless of the structural integrity of the used fuel, baskets, poisons, or storage canisters after an extended period of storage. This alternative assures criticality safety during transportation by implementing a concept that achieves moderator exclusion (no in-leakage of moderator into the used fuelmore » cavity). By relying upon a component inside of the transportation cask that provides a watertight function, a strong argument can be made that moderator intrusion is not credible and should not be a required assumption for criticality evaluations during normal or hypothetical accident conditions of transportation. This Transportation Task report addresses the assigned FY 2012 work that supports the proposed moderator exclusion concept as well as a standardized transportation system. The two tasks assigned were to (1) promote the proposed moderator exclusion concept to both regulatory and nuclear industry audiences and (2) advance specific technical issues in order to improve American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section III, Division 3 rules for storage and transportation containments. The common point behind both of the assigned tasks is to provide more options that can be used to resolve current issues being debated regarding the future transportation of used fuel after extended storage.« less

Alternative Fuels Data Center: Nevada Transportation Data for Alternative

Science.gov Websites

. Gasoline Diesel Natural Gas Electricity Transportation Fuel Consumption Source: State Energy Data System Renewable Power Plant Capacity (nameplate, MW) 1,684 Source: BioFuels Atlas from the National Renewable Source: Average prices per gasoline gallon equivalent (GGE) for the West Coast PADD from the Alternative

Alternative Fuels Data Center: Delaware Transportation Data for Alternative

Science.gov Websites

local stakeholders. Gasoline Diesel Natural Gas Transportation Fuel Consumption Source: State Energy Plants 1 Renewable Power Plant Capacity (nameplate, MW) 2 Source: BioFuels Atlas from the National /gallon $2.66/GGE Source: Average prices per gasoline gallon equivalent (GGE) for the Central Atlantic

Liquid Water Transport in the Reactant Channels of Proton Exchange Membrane Fuel Cells

NASA Astrophysics Data System (ADS)

Banerjee, Rupak

Water management has been identified as a critical issue in the development of PEM fuel cells for automotive applications. Water is present inside the PEM fuel cell in three phases, i.e. liquid phase, vapor phase and mist phase. Liquid water in the reactant channels causes flooding of the cell and blocks the transport of reactants to the reaction sites at the catalyst layer. Understanding the behavior of liquid water in the reactant channels would allow us to devise improved strategies for removing liquid water from the reactant channels. In situ fuel cell tests have been performed to identify and diagnose operating conditions which result in the flooding of the fuel cell. A relationship has been identified between the liquid water present in the reactant channels and the cell performance. A novel diagnostic technique has been established which utilizes the pressure drop multiplier in the reactant channels to predict the flooding of the cell or the drying-out of the membrane. An ex-situ study has been undertaken to quantify the liquid water present in the reactant channels. A new parameter, the Area Coverage Ratio (ACR), has been defined to identify the interfacial area of the reactant channel which is blocked for reactant transport by the presence of liquid water. A parametric study has been conducted to study the effect of changing temperature and the inlet relative humidity on the ACR. The ACR decreases with increase in current density as the gas flow rates increase, removing water more efficiently. With increase in temperature, the ACR decreases rapidly, such that by 60°C, there is no significant ACR to be reported. Inlet relative humidity of the gases does change the saturation of the gases in the channel, but did not show any significant effect on the ACR. Automotive powertrains, which is the target for this work, are continuously faced with transient changes. Water management under transient operating conditions is significantly more challenging and has not

Local mass and energy transports in evaporation processes from a vapor-liquid interface in a slit pore based on molecular dynamics

NASA Astrophysics Data System (ADS)

Fujiwara, K.; Shibahara, M.

2018-02-01

Molecular evaporation processes from a vapor-liquid interface formed in a slit-like pore were examined based on the classical molecular dynamics method, in order to elucidate a molecular mechanism of local mass and energy transports in a slit. The calculation system consisted of monatomic molecules and atoms which interact through the 12-6 Lennard-Jones potential. At first, a liquid was situated in a slit with a vapor-liquid interface, and instantaneous amounts of the mass and energy fluxes defined locally in the slit were obtained in two dimensions to reveal local fluctuation properties of the fluid in equilibrium states. Then, imposing a temperature gradient in the calculation system, non-equilibrium evaporation processes in the slit were investigated in details based on the local mass and energy fluxes. In this study, we focused on the fluid which is in the vicinity of the solid surface and in contact with the vapor phase. In the non-equilibrium evaporation processes, the results revealed that the local energy transport mechanism in the vicinity of the solid surface is different from that of the vapor phase, especially in the case of the relatively strong fluid-solid interaction. The results also revealed that the local mass transport in the vicinity of the solid surface can be interpreted based on the mechanism of the local energy transport, and the mechanism provides valuable information about pictures of the evaporation phenomena especially in the vicinity of the hydrophilic surfaces. It suggests that evaluating and changing this mechanism of the local energy transport are necessary to control the local mass flux more precisely in the vicinity of the solid surface.

Removal of hydrogen sulfide as ammonium sulfate from hydropyrolysis product vapors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marker, Terry L.; Felix, Larry G.; Linck, Martin B.

A system and method for processing biomass into hydrocarbon fuels that includes processing a biomass in a hydropyrolysis reactor resulting in hydrocarbon fuels and a process vapor stream and cooling the process vapor stream to a condensation temperature resulting in an aqueous stream. The aqueous stream is sent to a catalytic reactor where it is oxidized to obtain a product stream containing ammonia and ammonium sulfate. A resulting cooled product vapor stream includes non-condensable process vapors comprising H.sub.2, CH.sub.4, CO, CO.sub.2, ammonia and hydrogen sulfide.

Removal of hydrogen sulfide as ammonium sulfate from hydropyrolysis product vapors

DOEpatents

Marker, Terry L; Felix, Larry G; Linck, Martin B; Roberts, Michael J

2014-10-14

A system and method for processing biomass into hydrocarbon fuels that includes processing a biomass in a hydropyrolysis reactor resulting in hydrocarbon fuels and a process vapor stream and cooling the process vapor stream to a condensation temperature resulting in an aqueous stream. The aqueous stream is sent to a catalytic reactor where it is oxidized to obtain a product stream containing ammonia and ammonium sulfate. A resulting cooled product vapor stream includes non-condensable process vapors comprising H.sub.2, CH.sub.4, CO, CO.sub.2, ammonia and hydrogen sulfide.

Electrolyte vapor condenser

DOEpatents

Sederquist, Richard A.; Szydlowski, Donald F.; Sawyer, Richard D.

1983-01-01

A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well.

Electrolyte vapor condenser

DOEpatents

Sederquist, R.A.; Szydlowski, D.F.; Sawyer, R.D.

1983-02-08

A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well. 3 figs.

Mechanical Fatigue Testing of High Burnup Fuel for Transportation Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jy-An John; Wang, Hong

This report describes testing designed to determine the ability of high burnup (HBU) (>45 GWd/MTU) spent fuel to maintain its integrity under normal conditions of transportation. An innovative system, Cyclic Integrated Reversible-bending Fatigue Tester (CIRFT), has been developed at Oak Ridge National Laboratory (ORNL) to test and evaluate the mechanical behavior of spent nuclear fuel (SNF) under conditions relevant to storage and transportation. The CIRFT system is composed of a U-frame equipped with load cells for imposing the pure bending loads on the SNF rod test specimen and measuring the in-situ curvature of the fuel rod during bending using amore » set up with three linear variable differential transformers (LVDTs).« less

Mechanical Fatigue Testing of High-Burnup Fuel for Transportation Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jy-An; Wang, Hong

This report describes testing designed to determine the ability of high burnup (HBU) (>45 GWd/MTU) spent fuel to maintain its integrity under normal conditions of transportation. An innovative system, Cyclic Integrated Reversible-bending Fatigue Tester (CIRFT), has been developed at Oak Ridge National Laboratory (ORNL) to test and evaluate the mechanical behavior of spent nuclear fuel (SNF) under conditions relevant to storage and transportation. The CIRFT system is composed of a U-frame equipped with load cells for imposing the pure bending loads on the SNF rod test specimen and measuring the in-situ curvature of the fuel rod during bending using amore » set up with three linear variable differential transformers (LVDTs).« less

Distribution of volatile organic compounds in soil vapor in the vicinity of a defense fuel supply point, Hanahan, South Carolina

USGS Publications Warehouse

Robertson, J.F.; Aelion, C.M.; Vroblesky, D.A.

1993-01-01

Two passive soil-vapor sampling techniques were used in the vicinity of a defense fuel supply point in Hanahan, South Carolina, to identify areas of potential contamination of the shallow water table aquifer by volatile organic compounds (VOC's). Both techniques involved the burial of samplers in the vadose zone and the saturated bottom sediments of nearby streams. One method, the empty-tube technique, allowed vapors to pass through a permeable membrane and accumulate inside an inverted empty test tube. A sample was extracted and analyzed on site by using a portable gas chromatograph. As a comparison to this method, an activated-carbon technique, also was used in certain areas. This method uses a vapor collector consisting of a test tube containing activated carbon as a sorbent for VOC's.

Origin of the relatively low transport mobility of graphene grown through chemical vapor deposition

PubMed Central

Song, H. S.; Li, S. L.; Miyazaki, H.; Sato, S.; Hayashi, K.; Yamada, A.; Yokoyama, N.; Tsukagoshi, K.

2012-01-01

The reasons for the relatively low transport mobility of graphene grown through chemical vapor deposition (CVD-G), which include point defect, surface contamination, and line defect, were analyzed in the current study. A series of control experiments demonstrated that the determinant factor for the low transport mobility of CVD-G did not arise from point defects or surface contaminations, but stemmed from line defects induced by grain boundaries. Electron microscopies characterized the presence of grain boundaries and indicated the polycrystalline nature of the CVD-G. Field-effect transistors based on CVD-G without the grain boundary obtained a transport mobility comparative to that of Kish graphene, which directly indicated the detrimental effect of grain boundaries. The effect of grain boundary on transport mobility was qualitatively explained using a potential barrier model. Furthermore, the conduction mechanism of CVD-G was also investigated using the temperature dependence measurements. This study can help understand the intrinsic transport features of CVD-G. PMID:22468224

Influence of long-range transboundary transport on atmospheric water vapor mercury collected at the largest city of Tibet.

PubMed

Huang, Jie; Kang, Shichang; Tian, Lide; Guo, Junming; Zhang, Qianggong; Cong, Zhiyuan; Sillanpää, Mika; Sun, Shiwei; Tripathee, Lekhendra

2016-10-01

Monsoon circulation is an important process that affects long-range transboundary transport of anthropogenic contaminants such as mercury (Hg). During the Indian monsoon season of 2013, a total of 92 and 26 atmospheric water vapor samples were collected at Lhasa, the largest city of the Tibet, for Hg and major ions analysis, respectively. The relatively low pH/high electronic conductivity values, together with the fact that NH4(+) in atmospheric water vapor was even higher than that determined in precipitation of Lhasa, indicated the effects of anthropogenic perturbations through long-range transboundary atmospheric transport. Concentrations of Hg in atmospheric water vapor ranged from 2.5 to 73.7ngL(-1), with an average of 12.5ngL(-1). The elevated Hg and major ions concentrations, and electronic conductivity values were generally associated with weak acidic samples, and Hg mainly loaded with anthropogenic ions such as NH4(+). The results of principal component analysis and trajectory analysis suggested that anthropogenic emissions from the Indian subcontinent may have largely contributed to the determined Hg in atmospheric water vapor. Furthermore, our study reconfirmed that below-cloud scavenging contribution was significant for precipitation Hg in Lhasa, and evaluated that on average 74.1% of the Hg in precipitation could be accounted for by below-cloud scavenging. Copyright © 2016 Elsevier B.V. All rights reserved.

Alternative Fuels Data Center: Maine Transportation Data for Alternative

Science.gov Websites

connect with other local stakeholders. Gasoline Diesel Natural Gas Transportation Fuel Consumption Source Renewable Power Plants 58 Renewable Power Plant Capacity (nameplate, MW) 984 Source: BioFuels Atlas from the $2.96/gallon $2.66/GGE Source: Average prices per gasoline gallon equivalent (GGE) for the New England

Alternative Fuels Data Center: Hawaii Transportation Data for Alternative

Science.gov Websites

Diesel Natural Gas Transportation Fuel Consumption Source: State Energy Data System based on beta data Plant Capacity (nameplate, MW) 145 Source: BioFuels Atlas from the National Renewable Energy Laboratory $2.96/gallon $2.66/GGE Source: Average prices per gasoline gallon equivalent (GGE) for the West Coast

Alternative Fuels Data Center: Montana Transportation Data for Alternative

Science.gov Websites

. Gasoline Diesel Natural Gas Transportation Fuel Consumption Source: State Energy Data System based on beta Renewable Power Plant Capacity (nameplate, MW) 2,955 Source: BioFuels Atlas from the National Renewable /gallon $2.66/GGE Source: Average prices per gasoline gallon equivalent (GGE) for the Rocky Mountain PADD

The role of technology as air transportation faces the fuel situation

NASA Technical Reports Server (NTRS)

Driver, C.

1980-01-01

Perspectives on the air transportation fuel stituation are discussed including intercity air traffic, airline fuel consumption, fuel price effects on ticket price, and projected traffic and fuel useage between now and the year 2000. Actions taken by the airlines to reduce consumption are reviewed, as well as efforts currently underway to improve fuel consumption. Longer range technology payoffs resulting from NASA research programs are reviewed and results from studies on the use of alternate fuels are discussed.

Pipeline transportation of upgraded Yugoslavian lignite fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ljubicic, B.; Anderson, C.; Bukurov, Z.

1993-12-31

Hydraulic transport and handling procedures for coal are not widely used, but when practiced, they result in a technically and economically successful operation. Potentially the most attractive way to utilize lignitic coals for power generation would be to combine hydraulic mining techniques with aqueous ash removal, hydrothermal processing, solids concentration, and coal-water fuel (CWF) combustion. Technical and economic assessment of this operation is being implemented within the Yugoslavian-American Scientific Technical Cooperation Agreement. The Energy and Environmental Research Center (EERC), Grand Forks, North Dakota, with support from the U.S. Department of Energy, has entered into a jointly sponsored research project withmore » Electric Power of Serbia (EPS), Belgrade, Yugoslavia, to investigate the application of the nonevaporative hydrothermal drying procedure, commonly called hot-water drying (HWD), developed at the EERC, to the lignite from the Kovin deposit. Advances in hydrothermal treatment of low-rank coals (LRCs) at the EERC have enabled cheaper, more reactive LRCs to be used in coal-water fuels (CWFs). HWD is a high-temperature, nonevaporative drying technique carried out at high pressure in water that permanently alters the structure of LRC. It solves the stability problems by producing a safe, easily transported, liquid fuel that can be handled and used like oil. For continued or increased success, it is necessary to evaluate carefully all aspects of slurry technology that permit further optimization. This paper discusses some aspects of low-rank coal hydraulic transport combined with hydrothermal treatment as an alternative energy solution toward less oil dependence in Yugoslavia.« less

Effects of the Fuel Price Increase on the Operating Cost of Freight Transport Vehicles

NASA Astrophysics Data System (ADS)

Gohari, Adel; Matori, Nasir; Yusof, Khamaruzaman Wan; Toloue, Iraj; Myint, Kin Cho

2018-03-01

One of the most important criteria in freight modal choices is the transport operating cost in which fuel price changes has a significant effect on it. This paper presents the impact of fuel price increases on the operating cost of the different transport modes for the containerized freight transportation. In this study, an operating cost equation was applied to compare the operating cost of different freight transport vehicles as well as evaluation of the operating cost changes across a range of fuel prices between the current price and one-hundred percent increase. The equation consists of influential parameters such as fuel cost, driver wage and maintenance cost of a vehicle. It has been concluded that the effect of the fuel price increase on the operating cost of different freight transportation modes is not in the same rate. According to equation and effective parameters considered, comparing the results showed that truck has the highest cost, train has the largest increase in price. Finally, the ship is the most influenced vehicle in terms of operating cost percentage increase when the rate of fuel price increase, followed by train and truck.

Mountain waves modulate the water vapor distribution in the UTLS

NASA Astrophysics Data System (ADS)

Heller, Romy; Voigt, Christiane; Beaton, Stuart; Dörnbrack, Andreas; Giez, Andreas; Kaufmann, Stefan; Mallaun, Christian; Schlager, Hans; Wagner, Johannes; Young, Kate; Rapp, Markus

2017-12-01

The water vapor distribution in the upper troposphere-lower stratosphere (UTLS) region has a strong impact on the atmospheric radiation budget. Transport and mixing processes on different scales mainly determine the water vapor concentration in the UTLS. Here, we investigate the effect of mountain waves on the vertical transport and mixing of water vapor. For this purpose we analyze measurements of water vapor and meteorological parameters recorded by the DLR Falcon and NSF/NCAR Gulfstream V research aircraft taken during the Deep Propagating Gravity Wave Experiment (DEEPWAVE) in New Zealand. By combining different methods, we develop a new approach to quantify location, direction and irreversibility of the water vapor transport during a strong mountain wave event on 4 July 2014. A large positive vertical water vapor flux is detected above the Southern Alps extending from the troposphere to the stratosphere in the altitude range between 7.7 and 13.0 km. Wavelet analysis for the 8.9 km altitude level shows that the enhanced upward water vapor transport above the mountains is caused by mountain waves with horizontal wavelengths between 22 and 60 km. A downward transport of water vapor with 22 km wavelength is observed in the lee-side of the mountain ridge. While it is a priori not clear whether the observed fluxes are irreversible, low Richardson numbers derived from dropsonde data indicate enhanced turbulence in the tropopause region related to the mountain wave event. Together with the analysis of the water vapor to ozone correlation, we find indications for vertical transport followed by irreversible mixing of water vapor. For our case study, we further estimate greater than 1 W m-2 radiative forcing by the increased water vapor concentrations in the UTLS above the Southern Alps of New Zealand, resulting from mountain waves relative to unperturbed conditions. Hence, mountain waves have a great potential to affect the water vapor distribution in the UTLS. Our

Alternative Fuels Data Center: Arkansas Transportation Data for Alternative

Science.gov Websites

Diesel Natural Gas Electricity Transportation Fuel Consumption Source: State Energy Data System based on Renewable Power Plant Capacity (nameplate, MW) 1,349 Source: BioFuels Atlas from the National Renewable $2.50/gallon $2.50/GGE Diesel $2.61/gallon $2.35/GGE $2.96/gallon $2.66/GGE Source: Average prices per

Alternative Fuels Data Center: Nebraska Transportation Data for Alternative

Science.gov Websites

Diesel Natural Gas Transportation Fuel Consumption Source: State Energy Data System based on beta data Capacity (nameplate, MW) 546 Source: BioFuels Atlas from the National Renewable Energy Laboratory Videos $2.50/gallon $2.50/GGE Diesel $2.89/gallon $2.60/GGE $2.96/gallon $2.66/GGE Source: Average prices per

Improving Catalyst Efficiency in Bio-Based Hydrocarbon Fuels; NREL (National Renewable Energy Laboratory)

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

This article investigates upgrading biomass pyrolysis vapors to form hydrocarbon fuels and chemicals using catalysts with different concentrations of acid sites. It shows that greater separation of acid sites makes catalysts more efficient at producing hydrocarbon fuels and chemicals. The conversion of biomass into liquid transportation fuels has attracted significant attention because of depleting fossil fuel reserves and environmental concerns resulting from the use of fossil fuels. Biomass is a renewable resource, which is abundant worldwide and can potentially be exploited to produce transportation fuels that are less damaging to the environment. This renewable resource consists of cellulose (40–50%), hemicellulosemore » (25–35%), and lignin (16–33%) biopolymers in addition to smaller quantities of inorganic materials such as silica and alkali and alkaline earth metals (calcium and potassium). Fast pyrolysis is an attractive thermochemical technology for converting biomass into precursors for hydrocarbon fuels because it produces up to 75 wt% bio-oil,1 which can be upgraded to feedstocks and/or blendstocks for further refining to finished fuels. Bio-oil that has not been upgraded has limited applications because of the presence of oxygen-containing functional groups, derived from cellulose, hemicellulose and lignin, which gives rise to high acidity, high viscosity, low heating value, immiscibility with hydrocarbons and aging during storage. Ex situ catalytic vapor phase upgrading is a promising approach for improving the properties of bio-oil. The goal of this process is to reject oxygen and produce a bio-oil with improved properties for subsequent downstream conversion to hydrocarbons.« less

On direct and indirect methanol fuel cells for transportation applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gottesfield, S.

1996-04-01

Research on direct oxidation methanol fuel cells (DMFCs) and polymer electrolyte fuel cells (PEFCs) is discussed. Systems considered for transportation applications are addressed. The use of platinum/ruthenium anode electrocatalysts and platinum cathode electrocatalysts in polymer electrolyte DMFCs has resulted in significant performance enhancements.

Health assessment of gasoline and fuel oxygenate vapors: subchronic inhalation toxicity.

PubMed

Clark, Charles R; Schreiner, Ceinwen A; Parker, Craig M; Gray, Thomas M; Hoffman, Gary M

2014-11-01

Sprague Dawley rats were exposed via inhalation to vapor condensates of either gasoline or gasoline combined with various fuel oxygenates to assess whether their use in gasoline influences the hazard of evaporative emissions. Test substances included vapor condensates prepared from an EPA described "baseline gasoline" (BGVC), or gasoline combined with methyl tertiary butyl ether (G/MTBE), ethyl t-butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), ethanol (G/EtOH), or t-butyl alcohol (G/TBA). Target concentrations were 0, 2000, 10,000 or 20,000mg/m(3) and exposures were for 6h/day, 5days/week for 13weeks. A portion of the animals were maintained for a four week recovery period to determine the reversibility of potential adverse effects. Increased kidney weight and light hydrocarbon nephropathy (LHN) were observed in treated male rats in all studies which were reversible or nearly reversible after 4weeks recovery. LHN is unique to male rats and is not relevant to human toxicity. The no observed effect level (NOAEL) in all studies was 10,000mg/m(3), except for G/MTBE (<2000) and G/TBA (2000). The results provide evidence that use of the studied oxygenates are unlikely to increase the hazard of evaporative emissions during refueling, compared to those from gasoline alone. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Sustainable fuel for the transportation sector

PubMed Central

Agrawal, Rakesh; Singh, Navneet R.; Ribeiro, Fabio H.; Delgass, W. Nicholas

2007-01-01

A hybrid hydrogen-carbon (H2CAR) process for the production of liquid hydrocarbon fuels is proposed wherein biomass is the carbon source and hydrogen is supplied from carbon-free energy. To implement this concept, a process has been designed to co-feed a biomass gasifier with H2 and CO2 recycled from the H2-CO to liquid conversion reactor. Modeling of this biomass to liquids process has identified several major advantages of the H2CAR process. (i) The land area needed to grow the biomass is <40% of that needed by other routes that solely use biomass to support the entire transportation sector. (ii) Whereas the literature estimates known processes to be able to produce ≈30% of the United States transportation fuel from the annual biomass of 1.366 billion tons, the H2CAR process shows the potential to supply the entire United States transportation sector from that quantity of biomass. (iii) The synthesized liquid provides H2 storage in an open loop system. (iv) Reduction to practice of the H2CAR route has the potential to provide the transportation sector for the foreseeable future, using the existing infrastructure. The rationale of using H2 in the H2CAR process is explained by the significantly higher annualized average solar energy conversion efficiency for hydrogen generation versus that for biomass growth. For coal to liquids, the advantage of H2CAR is that there is no additional CO2 release to the atmosphere due to the replacement of petroleum with coal, thus eliminating the need to sequester CO2. PMID:17360377

Sustainable fuel for the transportation sector.

PubMed

Agrawal, Rakesh; Singh, Navneet R; Ribeiro, Fabio H; Delgass, W Nicholas

2007-03-20

A hybrid hydrogen-carbon (H(2)CAR) process for the production of liquid hydrocarbon fuels is proposed wherein biomass is the carbon source and hydrogen is supplied from carbon-free energy. To implement this concept, a process has been designed to co-feed a biomass gasifier with H(2) and CO(2) recycled from the H(2)-CO to liquid conversion reactor. Modeling of this biomass to liquids process has identified several major advantages of the H(2)CAR process. (i) The land area needed to grow the biomass is <40% of that needed by other routes that solely use biomass to support the entire transportation sector. (ii) Whereas the literature estimates known processes to be able to produce approximately 30% of the United States transportation fuel from the annual biomass of 1.366 billion tons, the H(2)CAR process shows the potential to supply the entire United States transportation sector from that quantity of biomass. (iii) The synthesized liquid provides H(2) storage in an open loop system. (iv) Reduction to practice of the H(2)CAR route has the potential to provide the transportation sector for the foreseeable future, using the existing infrastructure. The rationale of using H(2) in the H(2)CAR process is explained by the significantly higher annualized average solar energy conversion efficiency for hydrogen generation versus that for biomass growth. For coal to liquids, the advantage of H(2)CAR is that there is no additional CO(2) release to the atmosphere due to the replacement of petroleum with coal, thus eliminating the need to sequester CO(2).

Sustainable Transportation: Accelerating Widespread Adoption of Energy Efficient Vehicles & Fuels (Brochure)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2014-12-01

While energy efficient transportation strategies have the potential to simultaneously slash oil consumption and reduce greenhouse gas (GHG) emissions, a truly sustainable solution will require more than just putting drivers behind the wheels of new fuel-efficient cars. As the only national laboratory dedicated 100% to renewable energy and energy efficiency, the National Renewable Energy Laboratory (NREL) accelerates widespread adoption of high-performance, low-emission, energy-efficient passenger and freight vehicles, as well as alternative fuels and related infrastructure. Researchers collaborate closely with industry, government, and research partners, using a whole-systems approach to design better batteries, drivetrains, and engines, as well as thermal management,more » energy storage, power electronic, climate control, alternative fuel, combustion, and emission systems. NREL's sustainable transportation research, development, and deployment (RD&D) efforts are not limited to vehicles, roads, and fueling stations. The lab also explores ways to save energy and reduce GHGs by integrating transportation technology advancements with renewable energy generation, power grids and building systems, urban planning and policy, and fleet operations.« less

ECMWF Extreme Forecast Index for water vapor transport: A forecast tool for atmospheric rivers and extreme precipitation

NASA Astrophysics Data System (ADS)

Lavers, David A.; Pappenberger, Florian; Richardson, David S.; Zsoter, Ervin

2016-11-01

In winter, heavy precipitation and floods along the west coasts of midlatitude continents are largely caused by intense water vapor transport (integrated vapor transport (IVT)) within the atmospheric river of extratropical cyclones. This study builds on previous findings that showed that forecasts of IVT have higher predictability than precipitation, by applying and evaluating the European Centre for Medium-Range Weather Forecasts Extreme Forecast Index (EFI) for IVT in ensemble forecasts during three winters across Europe. We show that the IVT EFI is more able (than the precipitation EFI) to capture extreme precipitation in forecast week 2 during forecasts initialized in a positive North Atlantic Oscillation (NAO) phase; conversely, the precipitation EFI is better during the negative NAO phase and at shorter leads. An IVT EFI example for storm Desmond in December 2015 highlights its potential to identify upcoming hydrometeorological extremes, which may prove useful to the user and forecasting communities.

The Observed Relationship Between Water Vapor and Ozone in the Tropical Tropopause Saturation Layer and the Influence of Meridional Transport

NASA Technical Reports Server (NTRS)

Selkirk, Henry B.; Schoeberl, M. R.; Olsen, M. A.; Douglass, A. R.

2011-01-01

We examine balloonsonde observations of water vapor and ozone from three Ticosonde campaigns over San Jose, Costa Rica [10 N, 84 W] during northern summer and a fourth during northern winter. The data from the summer campaigns show that the uppermost portion of the tropical tropopause layer between 360 and 380 K, which we term the tropopause saturation layer or TSL, is characterized by water vapor mixing ratios from proximately 3 to 15 ppmv and ozone from approximately 50 ppbv to 250 ppbv. In contrast, the atmospheric water vapor tape recorder at 380 K and above displays a more restricted 4-7 ppmv range in water vapor mixing ratio. From this perspective, most of the parcels in the TSL fall into two classes - those that need only additional radiative heating to rise into the tape recorder and those requiring some combination of additional dehydration and mixing with drier air. A substantial fraction of the latter class have ozone mixing ratios greater than 150 ppbv, and with water vapor greater than 7 ppmv this air may well have been transported into the tropics from the middle latitudes in conjunction with high-amplitude equatorial waves. We examine this possibility with both trajectory analysis and transport diagnostics based on HIRDLS ozone data. We apply the same approach to study the winter season. Here a very different regime obtains as the ozone-water vapor scatter diagram of the sonde data shows the stratosphere and troposphere to be clearly demarcated with little evidence of mixing in of middle latitude air parcels.

Fuel cell system with combustor-heated reformer

DOEpatents

Pettit, William Henry

2000-01-01

A fuel cell system including a fuel reformer heated by a catalytic combustor fired by anode effluent and/or fuel from a liquid fuel supply providing fuel for the fuel cell. The combustor includes a vaporizer section heated by the combustor exhaust gases for vaporizing the fuel before feeding it into the combustor. Cathode effluent is used as the principle oxidant for the combustor.

Investigating the source, transport, and isotope composition of water vapor in the planetary boundary layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griffis, Timothy J.; Wood, Jeffrey D.; Baker, John M.

Increasing atmospheric humidity and convective precipitation over land provide evidence of intensification of the hydrologic cycle – an expected response to surface warming. The extent to which terrestrial ecosystems modulate these hydrologic factors is important to understand feedbacks in the climate system. We measured the oxygen and hydrogen isotope composition of water vapor at a very tall tower (185 m) in the upper Midwest, United States, to diagnose the sources, transport, and fractionation of water vapor in the planetary boundary layer (PBL) over a 3-year period (2010 to 2012). These measurements represent the first set of annual water vapor isotopemore » observations for this region. Several simple isotope models and cross-wavelet analyses were used to assess the importance of the Rayleigh distillation process, evaporation, and PBL entrainment processes on the isotope composition of water vapor. The vapor isotope composition at this tall tower site showed a large seasonal amplitude (mean monthly δ 18O v ranged from –40.2 to –15.9 ‰ and δ 2H v ranged from –278.7 to –113.0 ‰) and followed the familiar Rayleigh distillation relation with water vapor mixing ratio when considering the entire hourly data set. However, this relation was strongly modulated by evaporation and PBL entrainment processes at timescales ranging from hours to several days. The wavelet coherence spectra indicate that the oxygen isotope ratio and the deuterium excess ( d v) of water vapor are sensitive to synoptic and PBL processes. According to the phase of the coherence analyses, we show that evaporation often leads changes in d v, confirming that it is a potential tracer of regional evaporation. Isotope mixing models indicate that on average about 31 % of the growing season PBL water vapor is derived from regional evaporation. However, isoforcing calculations and mixing model analyses for high PBL water vapor mixing ratio events ( > 25 mmol mol –1) indicate that

Investigating the source, transport, and isotope composition of water vapor in the planetary boundary layer

DOE PAGES

Griffis, Timothy J.; Wood, Jeffrey D.; Baker, John M.; ...

2016-04-25

Increasing atmospheric humidity and convective precipitation over land provide evidence of intensification of the hydrologic cycle – an expected response to surface warming. The extent to which terrestrial ecosystems modulate these hydrologic factors is important to understand feedbacks in the climate system. We measured the oxygen and hydrogen isotope composition of water vapor at a very tall tower (185 m) in the upper Midwest, United States, to diagnose the sources, transport, and fractionation of water vapor in the planetary boundary layer (PBL) over a 3-year period (2010 to 2012). These measurements represent the first set of annual water vapor isotopemore » observations for this region. Several simple isotope models and cross-wavelet analyses were used to assess the importance of the Rayleigh distillation process, evaporation, and PBL entrainment processes on the isotope composition of water vapor. The vapor isotope composition at this tall tower site showed a large seasonal amplitude (mean monthly δ 18O v ranged from –40.2 to –15.9 ‰ and δ 2H v ranged from –278.7 to –113.0 ‰) and followed the familiar Rayleigh distillation relation with water vapor mixing ratio when considering the entire hourly data set. However, this relation was strongly modulated by evaporation and PBL entrainment processes at timescales ranging from hours to several days. The wavelet coherence spectra indicate that the oxygen isotope ratio and the deuterium excess ( d v) of water vapor are sensitive to synoptic and PBL processes. According to the phase of the coherence analyses, we show that evaporation often leads changes in d v, confirming that it is a potential tracer of regional evaporation. Isotope mixing models indicate that on average about 31 % of the growing season PBL water vapor is derived from regional evaporation. However, isoforcing calculations and mixing model analyses for high PBL water vapor mixing ratio events ( > 25 mmol mol –1) indicate that

Transport phenomena in alkaline direct ethanol fuel cells for sustainable energy production

NASA Astrophysics Data System (ADS)

An, L.; Zhao, T. S.

2017-02-01

Alkaline direct ethanol fuel cells (DEFC), which convert the chemical energy stored in ethanol directly into electricity, are one of the most promising energy-conversion devices for portable, mobile and stationary power applications, primarily because this type of fuel cell runs on a carbon-neutral, sustainable fuel and the electrocatalytic and membrane materials that constitute the cell are relatively inexpensive. As a result, the alkaline DEFC technology has undergone a rapid progress over the last decade. This article provides a comprehensive review of transport phenomena of various species in this fuel cell system. The past investigations into how the design and structural parameters of membrane electrode assemblies and the operating parameters affect the fuel cell performance are discussed. In addition, future perspectives and challenges with regard to transport phenomena in this fuel cell system are also highlighted.

Preliminary investigation of uncombusted auto fuel vapor dispersion within a residential garage microenvironment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lansari, A.; Streicher, J.J.; Huber, A.H.

1993-01-01

Evaporative emissions from vehicles in an attached garage may represent a significant source of indoor pollution and human exposure. A pilot field study was undertaken to investigate potential in-house dispersion of evaporative emissions of uncombusted fuels from a vehicle parked inside an attached garage. In a set of experiments using sulfur hexafluoride tracer gas, the multizonal mass balance model, CONTAM88, was used to predict interzonal air flow rates and SF6 concentration distributions within the garage and house. Several experiments were included to evaluate the effect of meteorology and mechanical mixing mechanisms on the dispersion of automobile fuel vapor. Measurements indicatedmore » that approximately three percent of the garage maximum concentration was measured in a room adjacent to the garage. The model successfully predicted garage concentrations under well mixed conditions, but underpredicted the measured concentrations within various rooms of the house, in which mixing was incomplete. Multizonal mass balance models such as CONTAM88 may be useful in approximating contaminant concentrations at various locations within the house.« less

Alternative transportation fuels: Infrastructure requirements and environmental impacts for ethanol and hydrogen

NASA Astrophysics Data System (ADS)

Wakeley, Heather L.

Alternative fuels could replace a significant portion of the 140 billion gallons of annual US gasoline use. Considerable attention is being paid to processes and technologies for producing alternative fuels, but an enormous investment in new infrastructure will be needed to have substantial impact on the demand for petroleum. The economics of production, distribution, and use, along with environmental impacts of these fuels, will determine the success or failure of a transition away from US petroleum dependence. This dissertation evaluates infrastructure requirements for ethanol and hydrogen as alternative fuels. It begins with an economic case study for ethanol and hydrogen in Iowa. A large-scale linear optimization model is developed to estimate average transportation distances and costs for nationwide ethanol production and distribution systems. Environmental impacts of transportation in the ethanol life cycle are calculated using the Economic Input-Output Life Cycle Assessment (EIO-LCA) model. An EIO-LCA Hybrid method is developed to evaluate impacts of future fuel production technologies. This method is used to estimate emissions for hydrogen production and distribution pathways. Results from the ethanol analyses indicate that the ethanol transportation cost component is significant and is the most variable. Costs for ethanol sold in the Midwest, near primary production centers, are estimated to be comparable to or lower than gasoline costs. Along with a wide range of transportation costs, environmental impacts for ethanol range over three orders of magnitude, depending on the transport required. As a result, intensive ethanol use should be encouraged near ethanol production areas. Fossil fuels are likely to remain the primary feedstock sources for hydrogen production in the near- and mid-term. Costs and environmental impacts of hydrogen produced from natural gas and transported by pipeline are comparable to gasoline. However, capital costs are prohibitive and

The electrolyte challenge for a direct methanol-air polymer electrolyte fuel cell operating at temperatures up to 200 C

NASA Technical Reports Server (NTRS)

Savinell, Robert; Yeager, Ernest; Tryk, Donald; Landau, Uziel; Wainright, Jesse; Gervasio, Dominic; Cahan, Boris; Litt, Morton; Rogers, Charles; Scherson, Daniel

1993-01-01

Novel polymer electrolytes are being evaluated for use in a direct methanol-air fuel cell operating at temperatures in excess of 100 C. The evaluation includes tests of thermal stability, ionic conductivity, and vapor transport characteristics. The preliminary results obtained to date indicate that a high temperature polymer electrolyte fuel cell is feasible. For example, Nafion 117 when equilibrated with phosphoric acid has a conductivity of at least 0.4 Omega(exp -1)cm(exp -1) at temperatures up to 200 C in the presence of 400 torr of water vapor and methanol vapor cross over equivalent to 1 mA/cm(exp 2) under a one atmosphere methanol pressure differential at 135 C. Novel polymers are also showing similar encouraging results. The flexibility to modify and optimize the properties by custom synthesis of these novel polymers presents an exciting opportunity to develop an efficient and compact methanol fuel cell.

METHANOL PRODUCTION FROM BIOMASS AND NATURAL GAS AS TRANSPORTATION FUEL

EPA Science Inventory

Two processes are examined for production of methanol. They are assessed against the essential requirements of a future alternative fuel for road transport: that it (i) is producible in amounts comparable to the 19 EJ of motor fuel annually consumed in the U.S., (ii) minimizes em...

Reduction of Convection in Closed Tube Vapor Transport Experiments

NASA Technical Reports Server (NTRS)

Naumann, R. J.; Tan, Sarwa Bakti; Shin, In-Seok; Kim, Joo Soo

2002-01-01

The primary objective of this effort was to develop a method for suppressing convective flows during the growth of mercurous chloride crystals by vapor transport in closed tubes to levels approaching those obtained in the microgravity environment. Mercurous chloride was chosen because it is a technologically interesting acoustical optical material whose optical properties are believed to be affected by convective flows. Since the Grashof number scales as the cube of the smallest dimension in the flow system, reduction of the size scale can be extremely effective in reducing unwanted convective flows. However, since materials of practical interest must be grown at least on the cm scale, reduction of the overall growth system is not feasible. But if the region just above the growing crystal could be restricted to a few mm, considerable reduction in flow velocity would result. By suspending an effusive barrier in the growth ampoule just above the growth interface, it should be possible to reduce the convective velocity in this vicinity to levels approaching flows in microgravity. If successful, this growth technique will offer a screening test for proposed space experiments that involve vapor transport to see if reduction of convection will result in improved material and will set a new standard against which the improvements obtained in microgravity may be judged. In addition, it may provide an improved method for preparing materials on Earth whose growth is affected adversely by convection. If the properties of this material can be improved there is a potential commercial interest from Brimrose Inc., who has agreed to fabricate and test devices from the crystals we have grown. This report describes the development of the growth facility, the purification processes developed for preparing the starting material, and the results from growth experiments with and without the effusive baffle. Mercurous chloride turned out to be a more difficult material to deal with than

Alternative Fuels Data Center: State Fees as Transportation Funding

Science.gov Websites

Transportation began collecting $0.015 per mile driven from 5,000 volunteer vehicles and issued a gas tax refund electricity, which are not currently subject to state fuel tax. These fees are meant to recover revenue the state would otherwise capture through the motor fuel tax, had the vehicle been running on gasoline or

Alternative Fuels Data Center: Utah Transportation Data for Alternative

Science.gov Websites

Transportation Fuel Consumption Source: State Energy Data System based on beta data converted to gasoline gallon Source: BioFuels Atlas from the National Renewable Energy Laboratory Case Studies Video thumbnail for /gallon $2.42/GGE $2.50/gallon $2.50/GGE Diesel $2.82/gallon $2.54/GGE $2.96/gallon $2.66/GGE Source

Reduction of fuel consumption and exhaust pollutant using intelligent transport systems.

PubMed

Nasir, Mostofa Kamal; Md Noor, Rafidah; Kalam, M A; Masum, B M

2014-01-01

Greenhouse gas emitted by the transport sector around the world is a serious issue of concern. To minimize such emission the automobile engineers have been working relentlessly. Researchers have been trying hard to switch fossil fuel to alternative fuels and attempting to various driving strategies to make traffic flow smooth and to reduce traffic congestion and emission of greenhouse gas. Automobile emits a massive amount of pollutants such as Carbon Monoxide (CO), hydrocarbons (HC), carbon dioxide (CO2), particulate matter (PM), and oxides of nitrogen (NO x ). Intelligent transport system (ITS) technologies can be implemented to lower pollutant emissions and reduction of fuel consumption. This paper investigates the ITS techniques and technologies for the reduction of fuel consumption and minimization of the exhaust pollutant. It highlights the environmental impact of the ITS application to provide the state-of-art green solution. A case study also advocates that ITS technology reduces fuel consumption and exhaust pollutant in the urban environment.

Reduction of Fuel Consumption and Exhaust Pollutant Using Intelligent Transport Systems

PubMed Central

Nasir, Mostofa Kamal; Md Noor, Rafidah; Kalam, M. A.; Masum, B. M.

2014-01-01

Greenhouse gas emitted by the transport sector around the world is a serious issue of concern. To minimize such emission the automobile engineers have been working relentlessly. Researchers have been trying hard to switch fossil fuel to alternative fuels and attempting to various driving strategies to make traffic flow smooth and to reduce traffic congestion and emission of greenhouse gas. Automobile emits a massive amount of pollutants such as Carbon Monoxide (CO), hydrocarbons (HC), carbon dioxide (CO2), particulate matter (PM), and oxides of nitrogen (NOx). Intelligent transport system (ITS) technologies can be implemented to lower pollutant emissions and reduction of fuel consumption. This paper investigates the ITS techniques and technologies for the reduction of fuel consumption and minimization of the exhaust pollutant. It highlights the environmental impact of the ITS application to provide the state-of-art green solution. A case study also advocates that ITS technology reduces fuel consumption and exhaust pollutant in the urban environment. PMID:25032239

Stratospheric water vapor in the NCAR CCM2

NASA Technical Reports Server (NTRS)

Mote, Philip W.; Holton, James R.

1992-01-01

Results are presented of the water vapor distribution in a 3D GCM with good vertical resolution, a state-of-the-art transport scheme, and a realistic water vapor source in the middle atmosphere. In addition to water vapor, the model transported methane and an idealized clock tracer, which provides transport times to and within the middle atmosphere. The water vapor and methane distributions are compared with Nimbus 7 SAMS and LIMS data and with in situ measurements. It is argued that the hygropause in the model is maintained not by 'freeze-drying' at the tops of tropical cumulonimbus, but by a balance between two sources and one sink. Since the southern winter dehydration is unrealistically intense, this balance most likely does not resemble the balance in the real atmosphere.

Atmospheric water vapor transport: Estimation of continental precipitation recycling and parameterization of a simple climate model. M.S. Thesis

NASA Technical Reports Server (NTRS)

Brubaker, Kaye L.; Entekhabi, Dara; Eagleson, Peter S.

1991-01-01

The advective transport of atmospheric water vapor and its role in global hydrology and the water balance of continental regions are discussed and explored. The data set consists of ten years of global wind and humidity observations interpolated onto a regular grid by objective analysis. Atmospheric water vapor fluxes across the boundaries of selected continental regions are displayed graphically. The water vapor flux data are used to investigate the sources of continental precipitation. The total amount of water that precipitates on large continental regions is supplied by two mechanisms: (1) advection from surrounding areas external to the region; and (2) evaporation and transpiration from the land surface recycling of precipitation over the continental area. The degree to which regional precipitation is supplied by recycled moisture is a potentially significant climate feedback mechanism and land surface-atmosphere interaction, which may contribute to the persistence and intensification of droughts. A simplified model of the atmospheric moisture over continents and simultaneous estimates of regional precipitation are employed to estimate, for several large continental regions, the fraction of precipitation that is locally derived. In a separate, but related, study estimates of ocean to land water vapor transport are used to parameterize an existing simple climate model, containing both land and ocean surfaces, that is intended to mimic the dynamics of continental climates.

Genesis, Pathways, and Terminations of Intense Global Water Vapor Transport in Association with Large-Scale Climate Patterns

NASA Astrophysics Data System (ADS)

Sellars, S. L.; Kawzenuk, B.; Nguyen, P.; Ralph, F. M.; Sorooshian, S.

2017-12-01

The CONNected objECT (CONNECT) algorithm is applied to global Integrated Water Vapor Transport data from the NASA's Modern-Era Retrospective Analysis for Research and Applications - Version 2 reanalysis product for the period of 1980 to 2016. The algorithm generates life-cycle records in time and space evolving strong vapor transport events. We show five regions, located in the midlatitudes, where events typically exist (off the coast of the southeast United States, eastern China, eastern South America, off the southern tip of South Africa, and in the southeastern Pacific Ocean). Global statistics show distinct genesis and termination regions and global seasonal peak frequency during Northern Hemisphere late fall/winter and Southern Hemisphere winter. In addition, the event frequency and geographical location are shown to be modulated by the Arctic Oscillation, Pacific North American Pattern, and the quasi-biennial oscillation. Moreover, a positive linear trend in the annual number of objects is reported, increasing by 3.58 objects year-over-year.

Personal exposure to JP-8 jet fuel vapors and exhaust at air force bases.

PubMed

Pleil, J D; Smith, L B; Zelnick, S D

2000-03-01

JP-8 jet fuel (similar to commercial/international jet A-1 fuel) is the standard military fuel for all types of vehicles, including the U.S. Air Force aircraft inventory. As such, JP-8 presents the most common chemical exposure in the Air Force, particularly for flight and ground crew personnel during preflight operations and for maintenance personnel performing routine tasks. Personal exposure at an Air Force base occurs through occupational exposure for personnel involved with fuel and aircraft handling and/or through incidental exposure, primarily through inhalation of ambient fuel vapors. Because JP-8 is less volatile than its predecessor fuel (JP-4), contact with liquid fuel on skin and clothing may result in prolonged exposure. The slowly evaporating JP-8 fuel tends to linger on exposed personnel during their interaction with their previously unexposed colleagues. To begin to assess the relative exposures, we made ambient air measurements and used recently developed methods for collecting exhaled breath in special containers. We then analyzed for certain volatile marker compounds for JP-8, as well as for some aromatic hydrocarbons (especially benzene) that are related to long-term health risks. Ambient samples were collected by using compact, battery-operated, personal whole-air samplers that have recently been developed as commercial products; breath samples were collected using our single-breath canister method that uses 1-L canisters fitted with valves and small disposable breathing tubes. We collected breath samples from various groups of Air Force personnel and found a demonstrable JP-8 exposure for all subjects, ranging from slight elevations as compared to a control cohort to > 100 [mutilpe] the control values. This work suggests that further studies should be performed on specific issues to obtain pertinent exposure data. The data can be applied to assessments of health outcomes and to recommendations for changes in the use of personal protective

Personal exposure to JP-8 jet fuel vapors and exhaust at air force bases.

PubMed Central

Pleil, J D; Smith, L B; Zelnick, S D

2000-01-01

JP-8 jet fuel (similar to commercial/international jet A-1 fuel) is the standard military fuel for all types of vehicles, including the U.S. Air Force aircraft inventory. As such, JP-8 presents the most common chemical exposure in the Air Force, particularly for flight and ground crew personnel during preflight operations and for maintenance personnel performing routine tasks. Personal exposure at an Air Force base occurs through occupational exposure for personnel involved with fuel and aircraft handling and/or through incidental exposure, primarily through inhalation of ambient fuel vapors. Because JP-8 is less volatile than its predecessor fuel (JP-4), contact with liquid fuel on skin and clothing may result in prolonged exposure. The slowly evaporating JP-8 fuel tends to linger on exposed personnel during their interaction with their previously unexposed colleagues. To begin to assess the relative exposures, we made ambient air measurements and used recently developed methods for collecting exhaled breath in special containers. We then analyzed for certain volatile marker compounds for JP-8, as well as for some aromatic hydrocarbons (especially benzene) that are related to long-term health risks. Ambient samples were collected by using compact, battery-operated, personal whole-air samplers that have recently been developed as commercial products; breath samples were collected using our single-breath canister method that uses 1-L canisters fitted with valves and small disposable breathing tubes. We collected breath samples from various groups of Air Force personnel and found a demonstrable JP-8 exposure for all subjects, ranging from slight elevations as compared to a control cohort to > 100 [mutilpe] the control values. This work suggests that further studies should be performed on specific issues to obtain pertinent exposure data. The data can be applied to assessments of health outcomes and to recommendations for changes in the use of personal protective

Energy analysis and break-even distance for transportation for biofuels in comparison to fossil fuels

USDA-ARS?s Scientific Manuscript database

In the present analysis various forms fuel from biomass and fossil sources, their mass and energy densities, and their break-even transportation distances to transport them effectively were analyzed. This study gives an insight on how many times more energy spent on transporting the fuels to differe...

Oil Price Uncertainty, Transport Fuel Demand and Public Health.

PubMed

He, Ling-Yun; Yang, Sheng; Chang, Dongfeng

2017-03-01

Based on the panel data of 306 cities in China from 2002 to 2012, this paper investigates China's road transport fuel (i.e., gasoline and diesel) demand system by using the Almost Ideal Demand System (AIDS) and the Quadratic AIDS (QUAIDS) models. The results indicate that own-priceelasticitiesfordifferentvehiclecategoriesrangefrom-1.215to-0.459(byAIDS)andfrom -1.399 to-0.369 (by QUAIDS). Then, this study estimates the air pollution emissions (CO, NOx and PM2.5) and public health damages from the road transport sector under different oil price shocks. Compared to the base year 2012, results show that a fuel price rise of 30% can avoid 1,147,270 tonnes of pollution emissions; besides, premature deaths and economic losses decrease by 16,149 cases and 13,817.953 million RMB yuan respectively; while based on the non-linear health effect model, the premature deaths and total economic losses decrease by 15,534 and 13,291.4 million RMB yuan respectively. Our study combines the fuel demand and health evaluation models and is the first attempt to address how oil price changes influence public health through the fuel demand system in China. Given its serious air pollution emission and substantial health damages, this paper provides important insights for policy makers in terms of persistent increasing in fuel consumption and the associated health and economic losses.

Nuclear Energy and Synthetic Liquid Transportation Fuels

NASA Astrophysics Data System (ADS)

McDonald, Richard

2012-10-01

This talk will propose a plan to combine nuclear reactors with the Fischer-Tropsch (F-T) process to produce synthetic carbon-neutral liquid transportation fuels from sea water. These fuels can be formed from the hydrogen and carbon dioxide in sea water and will burn to water and carbon dioxide in a cycle powered by nuclear reactors. The F-T process was developed nearly 100 years ago as a method of synthesizing liquid fuels from coal. This process presently provides commercial liquid fuels in South Africa, Malaysia, and Qatar, mainly using natural gas as a feedstock. Nuclear energy can be used to separate water into hydrogen and oxygen as well as to extract carbon dioxide from sea water using ion exchange technology. The carbon dioxide and hydrogen react to form synthesis gas, the mixture needed at the beginning of the F-T process. Following further refining, the products, typically diesel and Jet-A, can use existing infrastructure and can power conventional engines with little or no modification. We can then use these carbon-neutral liquid fuels conveniently long into the future with few adverse environmental impacts.

Vapor deposition of hardened niobium

DOEpatents

Blocher, Jr., John M.; Veigel, Neil D.; Landrigan, Richard B.

1983-04-19

A method of coating ceramic nuclear fuel particles containing a major amount of an actinide ceramic in which the particles are placed in a fluidized bed maintained at ca. 800.degree. to ca. 900.degree. C., and niobium pentachloride vapor and carbon tetrachloride vapor are led into the bed, whereby niobium metal is deposited on the particles and carbon is deposited interstitially within the niobium. Coating apparatus used in the method is also disclosed.

Analysis of hydrogen as a Transportation Fuel FY17 Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pratt, Richard M.; Luzi, Francesco; Wilcox Freeburg, Eric D.

This report summarizes the results of literature reviews, surveys and analyses performed to evaluate the potential of hydrogen-fueled vehicles to be an economically viable transportation alternative. Five existing and important drivers of expanding hydrogen-fueled transportation adoption are multi-billion dollar sales reservations of Nikola Class 8 trucks, CALSTART viability analysis of hybrid-hydrogen drayage trucks in the shipyard cargo application, analysis showing economic advantages of Fuel Cell Electric Vehicles (FCEV)s over Battery Electric Vehicles (BEV)s beginning at 150-mile ranges, the announcement of a commercial 5kg electrolyzer, and commercial plans or vehicle availability by nine vehicle manufacturers of FCEV passenger vehicles. But hydrogenmore » infrastructure availability needed to support broad adoption of hydrogen-fueled vehicles is limited to less than 50 publicly-available refueling stations, primarily in California. The demand side (consumer) economics associated with FCEV adoption showed strong economic sensitivity to the original vehicle’s fuel economy (mpg), distance traveled, and hydrogen (H2) generation costs. Seven use cases were used to evaluate the broad range of potential FCEV purchasers, including autonomous vehicle applications. Each consumer use case analysis resulted in a different hydrogen fuel cost that would be equivalent to the current fuel cost being paid by the consumer. The H2 generation costs (supply side) were sensitive to the volume of H2 supplied and H2 production costs needed to repay H2 supply facility capital costs and produce competitively-priced energy. H2FAST was used to more accurately incorporate capital, maintenance and production costs into a viable H2 supply cost to the consumer. When the H2 generation and consumer economics were combined, several applications with positive economics became clear. The availability of low-cost hydrogen pipeline connections, and therefore low-cost hydrogen, greatly

Proton exchange membrane fuel cell technology for transportation applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swathirajan, S.

1996-04-01

Proton Exchange Membrane (PEM) fuel cells are extremely promising as future power plants in the transportation sector to achieve an increase in energy efficiency and eliminate environmental pollution due to vehicles. GM is currently involved in a multiphase program with the US Department of Energy for developing a proof-of-concept hybrid vehicle based on a PEM fuel cell power plant and a methanol fuel processor. Other participants in the program are Los Alamos National Labs, Dow Chemical Co., Ballard Power Systems and DuPont Co., In the just completed phase 1 of the program, a 10 kW PEM fuel cell power plantmore » was built and tested to demonstrate the feasibility of integrating a methanol fuel processor with a PEM fuel cell stack. However, the fuel cell power plant must overcome stiff technical and economic challenges before it can be commercialized for light duty vehicle applications. Progress achieved in phase I on the use of monolithic catalyst reactors in the fuel processor, managing CO impurity in the fuel cell stack, low-cost electrode-membrane assembles, and on the integration of the fuel processor with a Ballard PEM fuel cell stack will be presented.« less

Water Vapor Feedbacks to Climate Change

NASA Technical Reports Server (NTRS)

Rind, David

1999-01-01

The response of water vapor to climate change is investigated through a series of model studies with varying latitudinal temperature gradients, mean temperatures, and ultimately, actual climate change configurations. Questions to be addressed include: what role does varying convection have in water vapor feedback; do Hadley Circulation differences result in differences in water vapor in the upper troposphere; and, does increased eddy energy result in greater eddy vertical transport of water vapor in varying climate regimes?

Fuel processor for fuel cell power system. [Conversion of methanol into hydrogen

DOEpatents

Vanderborgh, N.E.; Springer, T.E.; Huff, J.R.

1986-01-28

A catalytic organic fuel processing apparatus, which can be used in a fuel cell power system, contains within a housing a catalyst chamber, a variable speed fan, and a combustion chamber. Vaporized organic fuel is circulated by the fan past the combustion chamber with which it is in indirect heat exchange relationship. The heated vaporized organic fuel enters a catalyst bed where it is converted into a desired product such as hydrogen needed to power the fuel cell. During periods of high demand, air is injected upstream of the combustion chamber and organic fuel injection means to burn with some of the organic fuel on the outside of the combustion chamber, and thus be in direct heat exchange relation with the organic fuel going into the catalyst bed.

Alternative Fuels Data Center: District of Columbia Transportation Data for

Science.gov Websites

Electricity Transportation Fuel Consumption Source: State Energy Data System based on beta data converted to (nameplate, MW) 0 Source: BioFuels Atlas from the National Renewable Energy Laboratory Videos Text Version /GGE $2.96/gallon $2.66/GGE Source: Average prices per gasoline gallon equivalent (GGE) for the Central

Methods for conversion of lignocellulosic-derived products to transportation fuel precursors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lilga, Michael A.; Padmaperuma, Asanga B.

2017-10-03

Methods are disclosed for converting a biomass-derived product containing levulinic acid and/or gamma-valerolactone to a transportation fuel precursor product containing diesel like hydrocarbons. These methods are expected to produce fuel products at a reduced cost relative to conventional approaches.

Contactless Growth of ZnSe Single Crystals by Physical Vapor Transport

NASA Technical Reports Server (NTRS)

Su, Ching-Hua; George, M. A.; Feth, S.; Lehoczky, S. L.

1998-01-01

ZnSe crystals were grown by self-seeded physical vapor transport (PVT) technique in the horizontal configuration. The source materials were heat treated by H2 reduction to remove the oxide followed by baking under dynamic vacuum to adjust the source composition toward that of congruent sublimation. Contactless growth of ZnSe single crystals have been performed consistently using three different source materials. The crystals grew away from the wall during the later stage of the growth with large (110) facets tend to align parallel to the gravity direction. The Scanning Electron Micrography (SEM) micrographs and the Atomic Force Microscope (AFM) images showed that large (110) terraces and steps dominate the as-grown facets. The measured residual gas pressures in the processed ampoules agree well among various source materials and the major components were CO and H2. No preferred growth direction was found. The one-dimensional diffusion model on the mass flux of a multi-species PVT system was employed to analyze the conditions for contactless growth. The calculated thermal profile for supersaturation is very close to the thermal profile measured inside the empty furnace bore in the region of contactless growth. The effects of convective flows in the vapor phase inside the ampoule on the growth processes are discussed.

Shaping of the axial power density distribution in the core to minimize the vapor volume fraction at the outlet of the VVER-1200 fuel assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savander, V. I.; Shumskiy, B. E., E-mail: borisshumskij@yandex.ru; Pinegin, A. A.

The possibility of decreasing the vapor fraction at the VVER-1200 fuel assembly outlet by shaping the axial power density field is considered. The power density field was shaped by axial redistribution of the concentration of the burnable gadolinium poison in the Gd-containing fuel rods. The mathematical modeling of the VVER-1200 core was performed using the NOSTRA computer code.

VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eric M. Suuberg; Vahur Oja

1997-07-01

This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization whichmore » have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.« less

Salt transport extraction of transuranium elements from LWR fuel

DOEpatents

Pierce, R.D.; Ackerman, J.P.; Battles, J.E.; Johnson, T.R.; Miller, W.E.

1992-11-03

A process is described for separating transuranium actinide values from uranium values present in spent nuclear oxide fuels which contain rare earth and noble metal fission products. The oxide fuel is reduced with Ca metal in the presence of CaCl[sub 2] and a Cu--Mg alloy containing not less than about 25% by weight Mg at a temperature in the range of from about 750 C to about 850 C to precipitate uranium metal and some of the noble metal fission products leaving the Cu--Mg alloy having transuranium actinide metals and rare earth fission product metals and some of the noble metal fission products dissolved therein. The CaCl[sub 2] having CaO and fission products of alkali metals and the alkali earth metals and iodine dissolved therein is separated and electrolytically treated with a carbon electrode to reduce the CaO to Ca metal while converting the carbon electrode to CO and CO[sub 2]. The Ca metal and CaCl[sub 2] is recycled to reduce additional oxide fuel. The Cu--Mg alloy having transuranium metals and rare earth fission product metals and the noble metal fission products dissolved therein is contacted with a transport salt including MgCl[sub 2] to transfer Mg values from the transport salt to the Cu--Mg alloy while transuranium actinide and rare earth fission product metals transfer from the Cu--Mg alloy to the transport salt. Then the transport salt is mixed with a Mg--Zn alloy to transfer Mg values from the alloy to the transport salt while the transuranium actinide and rare earth fission product values dissolved in the salt are reduced and transferred to the Mg--Zn alloy. 2 figs.

Salt transport extraction of transuranium elements from lwr fuel

DOEpatents

Pierce, R. Dean; Ackerman, John P.; Battles, James E.; Johnson, Terry R.; Miller, William E.

1992-01-01

A process of separating transuranium actinide values from uranium values present in spent nuclear oxide fuels which contain rare earth and noble metal fission products. The oxide fuel is reduced with Ca metal in the presence of CaCl.sub.2 and a Cu--Mg alloy containing not less than about 25% by weight Mg at a temperature in the range of from about 750.degree. C. to about 850.degree. C. to precipitate uranium metal and some of the noble metal fission products leaving the Cu--Mg alloy having transuranium actinide metals and rare earth fission product metals and some of the noble metal fission products dissolved therein. The CaCl.sub.2 having CaO and fission products of alkali metals and the alkali earth metals and iodine dissolved therein is separated and electrolytically treated with a carbon electrode to reduce the CaO to Ca metal while converting the carbon electrode to CO and CO.sub.2. The Ca metal and CaCl.sub.2 is recycled to reduce additional oxide fuel. The Cu--Mg alloy having transuranium metals and rare earth fission product metals and the noble metal fission products dissolved therein is contacted with a transport salt including Mg Cl.sub.2 to transfer Mg values from the transport salt to the Cu--Mg alloy while transuranium actinide and rare earth fission product metals transfer from the Cu--Mg alloy to the transport salt. Then the transport salt is mixed with a Mg--Zn alloy to transfer Mg values from the alloy to the transport salt while the transuranium actinide and rare earth fission product values dissolved in the salt are reduced and transferred to the Mg--Zn alloy.

Hydrogen fuel dispensing station for transportation vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, S.P.N.; Richmond, A.A.

1995-07-01

A technical and economic assessment is being conducted of a hydrogen fuel dispensing station to develop an understanding of the infrastructure requirements for supplying hydrogen fuel for mobile applications. The study includes a process design of a conceptual small-scale, stand-alone, grassroots fuel dispensing facility (similar to the present-day gasoline stations) producing hydrogen by steam reforming of natural gas. Other hydrogen production processes (such as partial oxidation of hydrocarbons and water electrolysis) were reviewed to determine their suitability for manufacturing the hydrogen. The study includes an assessment of the environmental and other regulatory permitting requirements likely to be imposed on amore » hydrogen fuel dispensing station for transportation vehicles. The assessment concludes that a dispensing station designed to produce 0.75 million standard cubic feet of fuel grade (99.99%+ purity) hydrogen will meet the fuel needs of 300 light-duty vehicles per day. Preliminary economics place the total capital investment (in 1994 US dollars) for the dispensing station at $4.5 million and the annual operating costs at around $1 million. A discounted cash-flow analysis indicates that the fuel hydrogen product price (excluding taxes) to range between $1.37 to $2.31 per pound of hydrogen, depending upon the natural gas price, the plant financing scenario, and the rate of return on equity capital. A report on the assessment is due in June 1995. This paper presents a summary of the current status of the assessment.« less

Computational modeling of transport and electrochemical reactions in proton-exchange membrane fuel cells

NASA Astrophysics Data System (ADS)

Um, Sukkee

A comprehensive, multi-physics computational fuel cell dynamics (CFCD) model integrating electrochemical kinetics, charge transport, mass transport (particularly water transport), and flow dynamics is developed in this thesis. The numerical model is validated against published experimental data and utilized to generate results that reveal the internal operation of a PEM fuel cell. A number of model applications are demonstrated in the present work. First, the CFCD model is applied to explore hydrogen dilution effects in the anode feed. Detailed two-dimensional electrochemical and flow/transport simulations are provided to examine substantial anode concentration polarization due to hydrogen depletion at the reaction sites. A transient simulation of the cell current response to a step change in cell voltage is also attempted to elucidate characteristics of the dynamic response of a fuel cell for the first time. After the two-dimensional computational study, the CFCD model is applied to illustrate three-dimensional interactions between mass transfer and electrochemical kinetics. Emphasis is placed on obtaining a fundamental understanding of fully three-dimensional flow in the air cathode with interdigitated flowfield design and how it impacts the transport and electrochemical reaction processes. The innovative design concept for enhanced oxygen transport to, and effective water removal from the cathode, is explored numerically. Next, an analytical study of water transport is performed to investigate various water transport regimes of practical interest. The axial locations characteristic of anode water loss and cathode flooding are predicted theoretically and compared with numerical results. A continuous stirred fuel cell reactor (CSFCR) model is also proposed for the limiting situation where the anode and cathode sides reach equilibrium in water concentration with a thin ionomer membrane in between. In addition to the analytical solutions, a detailed water transport

SOIL VAPOR EXTRACTION TECHNOLOGY: REFERENCE HANDBOOK

EPA Science Inventory

Soil vapor extraction (SVE) systems are being used in Increasing numbers because of the many advantages these systems hold over other soil treatment technologies. SVE systems appear to be simple in design and operation, yet the fundamentals governing subsurface vapor transport ar...

Oil Price Uncertainty, Transport Fuel Demand and Public Health

PubMed Central

He, Ling-Yun; Yang, Sheng; Chang, Dongfeng

2017-01-01

Based on the panel data of 306 cities in China from 2002 to 2012, this paper investigates China’s road transport fuel (i.e., gasoline and diesel) demand system by using the Almost Ideal Demand System (AIDS) and the Quadratic AIDS (QUAIDS) models. The results indicate that own-price elasticities for different vehicle categories range from −1.215 to −0.459 (by AIDS) and from −1.399 to −0.369 (by QUAIDS). Then, this study estimates the air pollution emissions (CO, NOx and PM2.5) and public health damages from the road transport sector under different oil price shocks. Compared to the base year 2012, results show that a fuel price rise of 30% can avoid 1,147,270 tonnes of pollution emissions; besides, premature deaths and economic losses decrease by 16,149 cases and 13,817.953 million RMB yuan respectively; while based on the non-linear health effect model, the premature deaths and total economic losses decrease by 15,534 and 13,291.4 million RMB yuan respectively. Our study combines the fuel demand and health evaluation models and is the first attempt to address how oil price changes influence public health through the fuel demand system in China. Given its serious air pollution emission and substantial health damages, this paper provides important insights for policy makers in terms of persistent increasing in fuel consumption and the associated health and economic losses. PMID:28257076

Transport of Chemical Vapors from Subsurface Sources to Atmosphere as Affected by Shallow Subsurface and Atmospheric Conditions

NASA Astrophysics Data System (ADS)

Rice, A. K.; Smits, K. M.; Hosken, K.; Schulte, P.; Illangasekare, T. H.

2012-12-01

Understanding the movement and modeling of chemical vapor through unsaturated soil in the shallow subsurface when subjected to natural atmospheric thermal and mass flux boundary conditions at the land surface is of importance to applications such as landmine detection and vapor intrusion into subsurface structures. New, advanced technologies exist to sense chemical signatures at the land/atmosphere interface, but interpretation of these sensor signals to make assessment of source conditions remains a challenge. Chemical signatures are subject to numerous interactions while migrating through the unsaturated soil environment, attenuating signal strength and masking contaminant source conditions. The dominant process governing movement of gases through porous media is often assumed to be Fickian diffusion through the air phase with minimal or no quantification of other processes contributing to vapor migration, such as thermal diffusion, convective gas flow due to the displacement of air, expansion/contraction of air due to temperature changes, temporal and spatial variations of soil moisture and fluctuations in atmospheric pressure. Soil water evaporation and interfacial mass transfer add to the complexity of the system. The goal of this work is to perform controlled experiments under transient conditions of soil moisture, temperature and wind at the land/atmosphere interface and use the resulting dataset to test existing theories on subsurface gas flow and iterate between numerical modeling efforts and experimental data. Ultimately, we aim to update conceptual models of shallow subsurface vapor transport to include conditionally significant transport processes and inform placement of mobile sensors and/or networks. We have developed a two-dimensional tank apparatus equipped with a network of sensors and a flow-through head space for simulation of the atmospheric interface. A detailed matrix of realistic atmospheric boundary conditions was applied in a series of

Driving it home: choosing the right path for fueling North America's transportation future

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ann Bordetsky; Susan Casey-Lefkowitz; Deron Lovaas

2007-06-15

North America faces an energy crossroads. With the world fast approaching the end of cheap, plentiful conventional oil, we must choose between developing ever-dirtier sources of fossil fuels -- at great cost to our health and environment -- or setting a course for a more sustainable energy future of clean, renewable fuels. This report explores the full scale of the damage done by attempts to extract oil from liquid coal, oil shale, and tar sands; examines the risks for investors of gambling on these dirty fuel sources; and lays out solutions for guiding us toward a cleaner fuel future. Tablemore » of contents: Executive Summary; Chapter 1: Transportation Fuel at a Crossroads; Chapter 2: Canadian Tar Sands: Scraping the Bottom of the Barrel in Endangered Forests; Chapter 3: Oil Shale Extraction: Drilling Through the American West; Chapter 4: Liquid Coal: A 'Clean Fuel' Mirage; Chapter 5: The Investment Landscape: Dirty Fuels Are Risky Business; Chapter 6: The Clean Path for Transportation and Conclusion.« less

A Characterization Of Alcohol Fuel Vapor For Wavelength Modulation Spectroscopy Applied To Microgravity Flame Spread

NASA Technical Reports Server (NTRS)

Kulis, Michael J.; Perry, David S.; Miller, Fletcher; Piltch, Nancy

2003-01-01

A diode laser diagnostic is being developed for use in an ongoing investigation of flame spread in microgravity at NASA Glenn Research Center. Flame spread rates through non-homogenous gas mixtures are significantly different in a microgravity environment because of buoyancy and possibly hydrostatic pressure effects. These effects contribute to the fuel vapor concentration ahead of the flame being altered so that flame spread is more rapid in microgravity. This paper describes spectral transmission measurements made through mixtures of alcohol, water vapor, and nitrogen in a gas cell that was designed and built to allow measurements at temperatures up to 500 C. The alcohols considered are methanol, ethanol, and n-propanol. The basic technique of wavelength modulation spectroscopy for gas species measurements in microgravity was developed by Silver et al. For this technique to be applicable, one must carefully choose the spectral features over which the diode laser is modulated to provide good sensitivity and minimize interference from other molecular lines such as those in water. Because the methanol spectrum was not known with sufficient resolution in the wavelength region of interest, our first task was to perform high-resolution transmission measurements with an FTIR spectrometer for methanol vapor in nitrogen, followed recently by ethanol and n-propanol. A computer program was written to generate synthesized data to mimic that expected from the experiment using the laser diode, and results from that simulation are also presented.

Doping and electronic properties of GaAs grown by close-spaced vapor transport from powder sources for scalable III–V photovoltaics

DOE PAGES

Ritenour, Andrew J.; Boucher, Jason W.; DeLancey, Robert; ...

2014-09-01

The high balance-of-system costs of photovoltaic (PV) installations indicate that reductions in cell $/W costs alone are likely insufficient for PV electricity to reach grid parity unless energy conversion efficiency is also increased. Technologies which yield both high-efficiency cells (>25%) and maintain low costs are needed. GaAs and related III-V semiconductors are used in the highest-efficiency single- and multi-junction photovoltaics, but the technology is too expensive for non-concentrated terrestrial applications. This is due in part to the difficulty of scaling the metal-organic chemical vapor deposition (MOCVD) process, which relies on expensive reactors and employs toxic and pyrophoric gas-phase precursors suchmore » as arsine and trimethyl gallium, respectively. In this study, we describe GaAs films made by an alternative close-spaced vapor transport (CSVT) technique which is carried out at atmospheric pressure and requires only bulk GaAs, water vapor, and a temperature gradient in order to deposit crystalline films with similar electronic properties to that of GaAs deposited by MOCVD. CSVT is similar to the vapor transport process used to deposit CdTe thin films and is thus a potentially scalable low-cost route to GaAs thin films.« less

Stability of Materials in High Temperature Water Vapor: SOFC Applications

NASA Technical Reports Server (NTRS)

Opila, E. J.; Jacobson, N. S.

2010-01-01

Solid oxide fuel cell material systems require long term stability in environments containing high-temperature water vapor. Many materials in fuel cell systems react with high-temperature water vapor to form volatile hydroxides which can degrade cell performance. In this paper, experimental methods to characterize these volatility reactions including the transpiration technique, thermogravimetric analysis, and high pressure mass spectrometry are reviewed. Experimentally determined data for chromia, silica, and alumina volatility are presented. In addition, data from the literature for the stability of other materials important in fuel cell systems are reviewed. Finally, methods for predicting material recession due to volatilization reactions are described.

Performance of a multiple venturi fuel-air preparation system. [fuel injection for gas turbines

NASA Technical Reports Server (NTRS)

Tacina, R. R.

1979-01-01

Spatial fuel-air distributions, degree of vaporization, and pressure drop were measured 16.5 cm downstream of the fuel injection plane of a multiple Venturi tube fuel injector. Tests were performed in a 12 cm tubular duct. Test conditions were: a pressure of 0.3 MPa, inlet air temperature from 400 to 800K, air velocities of 10 and 20 m/s, and fuel-air ratios of 0.010 and 0.020. The fuel was Diesel #2. Spatial fuel-air distributions were within + or - 20 percent of the mean at inlet air temperatures above 450K. At an inlet air temperature of 400K, the fuel-air distribution was measured when a 50 percent blockage plate was placed 9.2 cm upstream of the fuel injection plane to distort the inlet air velocity fuel injection plane to distort the inlet air velocity profile. Vaporization of the fuel was 50 percent complete at an inlet air temperature of 400K and the percentage increased linearly with temperature to complete vaporization at 600K. The pressure drop was 3 percent at the design point which was three times greater than the designed value and the single tube experiment value. No autoignition or flashback was observed at the conditions tested.

Wells to wheels: Environmental implications of natural gas as a transportation fuel

DOE PAGES

Cai, Hao; Burnham, Andrew; Chen, Rui; ...

2017-07-25

Expanded use of natural gas (NG) as a transportation fuel in the United States requires understanding its environmental, technological, and economic performance. We analyzed water consumption for NG production in major U.S. shale gas plays from recent reports and studies. Also, we assessed the water consumption, greenhouse gas (GHG) emissions, and air emissions of using compressed and liquefied NG as transportation fuels by three heavyduty NG vehicles (NGV) types from a wells-to-wheels (WTW) perspective, using the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET®) model developed at Argonne National Laboratory. We reviewed recent work on quantifying methane leakagemore » in the NG supply chain and vehicle use to improve the estimates of this important factor to GHG emissions of NGVs. These results show that the NGVs could reduce water consumption significantly and offer air emissions reduction benefits compared to their diesel counterparts. WTW GHG emissions of NGVs are largely driven by the vehicle fuel efficiency, and methane leakage rates of the NG supply chain and vehicle end use, and are slightly higher than those of the diesel counterparts with the estimated WTW methane leakage. We also analyzed costs of operating NGVs relative to diesel vehicles and found that the cost-effectiveness of NGVs is impacted by incremental cost of NG storage tanks and price difference between NG and diesel fuels. Our findings for NG as a transportation fuel for different vehicle technologies shed light on their environmental impacts and the economics from the WTW holistic point of view.« less

76 FR 67287 - Alternative Fuel Transportation Program; Alternative Fueled Vehicle Credit Program (Subpart F...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-31

... infrastructure, nonroad equipment, and emerging technologies related to those electric drive vehicles. As... for investment in an emerging technology relating to any'' of the enumerated electric drive vehicles... Fuel Transportation Program (AFTP or Program), by including EISA-specified electric drive vehicles and...

Homojunction GaAs solar cells grown by close space vapor transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boucher, Jason W.; Ritenour, Andrew J.; Greenaway, Ann L.

2014-06-08

We report on the first pn junction solar cells grown by homoepitaxy of GaAs using close space vapor transport (CSVT). Cells were grown both on commercial wafer substrates and on a CSVT absorber film, and had efficiencies reaching 8.1%, open circuit voltages reaching 909 mV, and internal quantum efficiency of 90%. The performance of these cells is partly limited by the electron diffusion lengths in the wafer substrates, as evidenced by the improved peak internal quantum efficiency in devices fabricated on a CSVT absorber film. Unoptimized highly-doped n-type emitters also limit the photocurrent, indicating that thinner emitters with reduced doping,more » and ultimately wider band gap window or surface passivation layers, are required to increase the efficiency.« less

Cross‐Saharan transport of water vapor via recycled cold pool outflows from moist convection

PubMed Central

Trzeciak, Tomasz M.; Garcia‐Carreras, Luis

2017-01-01

Abstract Very sparse data have previously limited observational studies of meteorological processes in the Sahara. We present an observed case of convectively driven water vapor transport crossing the Sahara over 2.5 days in June 2012, from the Sahel in the south to the Atlas in the north. A daily cycle is observed, with deep convection in the evening generating moist cold pools that fed the next day's convection; the convection then generated new cold pools, providing a vertical recycling of moisture. Trajectories driven by analyses were able to capture the direction of the transport but not its full extent, particularly at night when cold pools are most active, and analyses missed much of the water content of cold pools. The results highlight the importance of cold pools for moisture transport, dust and clouds, and demonstrate the need to include these processes in models in order to improve the representation of Saharan atmosphere. PMID:28344367

Solar Energy for Transportation Fuel (LBNL Science at the Theater)

ScienceCinema

Lewis, Nate

2018-05-25

Nate Lewis' talk looks at the challenge of capturing solar energy and storing it as an affordable transportation fuel - all on a scale necessary to reduce global warming. Overcoming this challenge will require developing new materials that can use abundant and inexpensive elements rather than costly and rare materials. He discusses the promise of new materials in the development of carbon-free alternatives to fossil fuel.

ESTEEM - Encouraging School Transportation Effective Energy Management - Fuel Economy Management Handbook for Directors of Pupil Transportation, School District Administrators, Transportation Department Management.

ERIC Educational Resources Information Center

BRI Systems, Inc., Phoenix, AZ.

This publication is a guide for school districts to reduce pupil transportation costs and save energy. The information presented is based upon: (1) energy saving programs implemented by school districts; (2) government and industry research efforts in fuel economy; (3) the successful experiences of commercial trucking fleets to save fuel; and (4)…

Organic solar cells with graphene electrodes and vapor printed poly(3,4-ethylenedioxythiophene) as the hole transporting layers.

PubMed

Park, Hyesung; Howden, Rachel M; Barr, Miles C; Bulović, Vladimir; Gleason, Karen; Kong, Jing

2012-07-24

For the successful integration of graphene as a transparent conducting electrode in organic solar cells, proper energy level alignment at the interface between the graphene and the adjacent organic layer is critical. The role of a hole transporting layer (HTL) thus becomes more significant due to the generally lower work function of graphene compared to ITO. A commonly used HTL material with ITO anodes is poly(3,4-ethylenedioxythiophene) (PEDOT) with poly(styrenesulfonate) (PSS) as the solid-state dopant. However, graphene's hydrophobic surface renders uniform coverage of PEDOT:PSS (aqueous solution) by spin-casting very challenging. Here, we introduce a novel, yet simple, vapor printing method for creating patterned HTL PEDOT layers directly onto the graphene surface. Vapor printing represents the implementation of shadow masking in combination with oxidative chemical vapor deposition (oCVD). The oCVD method was developed for the formation of blanket (i.e., unpatterened) layers of pure PEDOT (i.e., no PSS) with systematically variable work function. In the unmasked regions, vapor printing produces complete, uniform, smooth layers of pure PEDOT over graphene. Graphene electrodes were synthesized under low-pressure chemical vapor deposition (LPCVD) using a copper catalyst. The use of another electron donor material, tetraphenyldibenzoperiflanthene, instead of copper phthalocyanine in the organic solar cells also improves the power conversion efficiency. With the vapor printed HTL, the devices using graphene electrodes yield comparable performances to the ITO reference devices (η(p,LPCVD) = 3.01%, and η(p,ITO) = 3.20%).

Conversion to a Hydrogen Fuel Transportation Industry, Incremental Route or Direct Route

DTIC Science & Technology

2005-03-18

applications and direct use applications . Hydrogen fuel cells reverse the hydrolysis process by taking oxygen from the air to produce water, heat and an...exploring platinum/ ruthenium catalysts that are more resistant to CO. PEM fuel cells are used primarily for transportation applications and some stationary...21 vi vii LIST OF ILLUSTRATIONS FIGURE 1 EPOCH OF FOSSIL FUELS IN HUMAN HISTORY

NREL - Advanced Vehicles and Fuels Basics - Center for Transportation Technologies and Systems 2010

ScienceCinema

Dan; Arvizu; Barbara; Goodman; Robert; McCormick; Tony; Markel; Matt; Keyser; Sreekant; Narumanchi; Rob; Farrington

2017-12-09

We can improve the fuel economy of our cars, trucks, and buses by designing them to use the energy in fuels more efficiently. Researchers at the National Renewable Energy Laboratory (NREL) are helping the nation achieve these goals by developing transportation technologies like: advanced vehicle systems and components; alternative fuels; as well as fuel cells, hybrid electric, and plug-in hybrid vehicles.

High burn-up spent nuclear fuel transport reliability investigation

DOE PAGES

Wang, Jy-An; Wang, Hong; Jiang, Hao; ...

2018-04-15

Transportation packages for spent nuclear fuel (SNF) must meet safety requirements under normal and accident conditions as specified by federal regulations. During road or rail transportation, SNF will experience unique conditions that could affect the structural integrity of the cladding due to vibrational and impact loading. Lack of SNF inertia-induced dynamic fatigue data, especially for the high burn-up (HBU) SNF systems, has brought significant challenges to quantify the reliability of SNF during transportation with a high degree of confidence. To address this shortcoming, Oak Ridge National Laboratory (ORNL) developed a SNF vibration testing protocol without fuel pellets removal, which hasmore » provided significant insight regarding the dynamics of mechanical interactions between pellet and cladding. This research has provided a detailed understanding about the effect of loading rate and loading mode on the fatigue damage evolution of HBU SNF under normal conditions of transport (NCT). Static and dynamic loading experimental data were generated for SNF under simulated transportation environments using a cyclic integrated reversible-bending fatigue tester (CIRFT), an enabling hot-cell testing technology developed at ORNL. SNF flexural tensile strength and fatigue S-N data from pressurized water reactors (PWRs) and boiling water reactor (BWR) HBU SNF are presented in this paper, including the potential effects of pellet-cladding interface bonding, hydride reorientation, and thermal annealing to SNF vibration reliability. The data presented here can be used to meet the nuclear industry and U.S. Nuclear Regulatory Commission needs in safety of SNF transportation operations.« less

High burn-up spent nuclear fuel transport reliability investigation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jy-An; Wang, Hong; Jiang, Hao

Transportation packages for spent nuclear fuel (SNF) must meet safety requirements under normal and accident conditions as specified by federal regulations. During road or rail transportation, SNF will experience unique conditions that could affect the structural integrity of the cladding due to vibrational and impact loading. Lack of SNF inertia-induced dynamic fatigue data, especially for the high burn-up (HBU) SNF systems, has brought significant challenges to quantify the reliability of SNF during transportation with a high degree of confidence. To address this shortcoming, Oak Ridge National Laboratory (ORNL) developed a SNF vibration testing protocol without fuel pellets removal, which hasmore » provided significant insight regarding the dynamics of mechanical interactions between pellet and cladding. This research has provided a detailed understanding about the effect of loading rate and loading mode on the fatigue damage evolution of HBU SNF under normal conditions of transport (NCT). Static and dynamic loading experimental data were generated for SNF under simulated transportation environments using a cyclic integrated reversible-bending fatigue tester (CIRFT), an enabling hot-cell testing technology developed at ORNL. SNF flexural tensile strength and fatigue S-N data from pressurized water reactors (PWRs) and boiling water reactor (BWR) HBU SNF are presented in this paper, including the potential effects of pellet-cladding interface bonding, hydride reorientation, and thermal annealing to SNF vibration reliability. The data presented here can be used to meet the nuclear industry and U.S. Nuclear Regulatory Commission needs in safety of SNF transportation operations.« less

Identification of vapor-phase chemical warfare agent simulants and rocket fuels using laser-induced breakdown spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stearns, Jaime A.; McElman, Sarah E.; Dodd, James A.

2010-05-01

Application of laser-induced breakdown spectroscopy (LIBS) to the identification of security threats is a growing area of research. This work presents LIBS spectra of vapor-phase chemical warfare agent simulants and typical rocket fuels. A large dataset of spectra was acquired using a variety of gas mixtures and background pressures and processed using partial least squares analysis. The five compounds studied were identified with a 99% success rate by the best method. The temporal behavior of the emission lines as a function of chamber pressure and gas mixture was also investigated, revealing some interesting trends that merit further study.

Investigation of diamond deposition by chemical vapor transport with hydrogen

NASA Astrophysics Data System (ADS)

Piekarczyk, Wladyslaw; Messier, Russell F.; Roy, Rustum; Engdahl, Chris

1990-12-01

The carbon-hydrogen chemical vapor transport system was examined in accordance with a four-stage transport model. A result of this examination is that graphite co-deposition could be avoided when diamond is deposited from gas solutions under-saturated with respect to diamond. Actual deposition experiments showed that this unusual requirement can be fulfilled but only for the condition that the transport distance between the carbon source and the substrate surface is short. In such a case diamond can be deposited equally from super-saturated as well as from under-saturated gas solutions. On the basis of thermodynamic considerations a possible explanation of this unusual phenomenon is given. It is shown that there is a possibility of deposition of diamond from both super-saturated as well as under-saturated gas solutions but only on the condition that they are in a non-equilibrium state generally called the activated state. A model of the diamond deposition process consisting of two steps is proposed. In the first step diamond and graphite are deposited simultaneously. The most important carbon deposition reaction is C2H2(g) + 2 H(g) C(diamond graphite) + CH(g). The amount of co-deposited graphite is not a direct function of the saturation state of the gas phase. In the second step graphite is etched according to the most probable reaction C(graphite) + 4 H(g) CH4(g). Atomic hydrogen in a super-equilibrium concentration is necessary not only to etch graphite but also to precipitate and graphite. 1.

Experimental study of flash boiling spray vaporization through quantitative vapor concentration and liquid temperature measurements

NASA Astrophysics Data System (ADS)

Zhang, Gaoming; Hung, David L. S.; Xu, Min

2014-08-01

Flash boiling sprays of liquid injection under superheated conditions provide the novel solutions of fast vaporization and better air-fuel mixture formation for internal combustion engines. However, the physical mechanisms of flash boiling spray vaporization are more complicated than the droplet surface vaporization due to the unique bubble generation and boiling process inside a superheated bulk liquid, which are not well understood. In this study, the vaporization of flash boiling sprays was investigated experimentally through the quantitative measurements of vapor concentration and liquid temperature. Specifically, the laser-induced exciplex fluorescence technique was applied to distinguish the liquid and vapor distributions. Quantitative vapor concentration was obtained by correlating the intensity of vapor-phase fluorescence with vapor concentration through systematic corrections and calibrations. The intensities of two wavelengths were captured simultaneously from the liquid-phase fluorescence spectra, and their intensity ratios were correlated with liquid temperature. The results show that both liquid and vapor phase of multi-hole sprays collapse toward the centerline of the spray with different mass distributions under the flash boiling conditions. Large amount of vapor aggregates along the centerline of the spray to form a "gas jet" structure, whereas the liquid distributes more uniformly with large vortexes formed in the vicinity of the spray tip. The vaporization process under the flash boiling condition is greatly enhanced due to the intense bubble generation and burst. The liquid temperature measurements show strong temperature variations inside the flash boiling sprays with hot zones present in the "gas jet" structure and vortex region. In addition, high vapor concentration and closed vortex motion seem to have inhibited the heat and mass transfer in these regions. In summary, the vapor concentration and liquid temperature provide detailed information

Influence of absorption by environmental water vapor on radiation transfer in wildland fires

Treesearch

D. Frankman; B. W. Webb; B. W. Butler

2008-01-01

The attenuation of radiation transfer from wildland flames to fuel by environmental water vapor is investigated. Emission is tracked from points on an idealized flame to locations along the fuel bed while accounting for absorption by environmental water vapor in the intervening medium. The Spectral Line Weighted-sum-of-gray-gases approach was employed for treating the...

Cryogenic foam insulation for LH2 fueled subsonic transports

NASA Technical Reports Server (NTRS)

Sharpe, E. L.; Helenbrook, R. G.

1978-01-01

Shortages of petroleum-based aircraft fuels are foreseen before the end of the century. To cope with such shortages, NASA is developing a commercial aircraft which can operate on liquid hydrogen. Various foam insulators for LH2 storage are considered in terms of thermal performance and service life. Of the cryogenic foams considered (plain foam, foam with flame retardants and fiberglass reinforcement, and foam with vapor barriers), polyurethane foams were found to be the best. Tests consisted of heating a 5 cm layer of insulation around an aluminum tank containing LH2 to 316 K, and then cooling it to 266 K, while the inner surface was maintained at LH2 temperature (20 K).

Understanding of ammonia transport in PEM fuel cells

NASA Astrophysics Data System (ADS)

Jung, Myunghee

This dissertation investigates ammonia (NH3) as a fuel contaminant to the anode in Proton Exchange Membrane Fuel Cells (PEMFCs). Since NH 3 is fed to the anode in a gas phase and transferred to the cathode, the effect of a contaminant is distributed through MEA and quite complicated. This study is focused on the investigation of mechanism of NH3 transport and the isolation of multiple effects to degrade the performance of fuel cell. An External Reference Electrode (ERE) was employed to decouple the effect of individual electrode and explain the mechanism of NH3 contamination. A mechanism of NH3 transport is proposed and supported by data for various inlet conditions in a N2/N2 laboratory-scale fuel cell at Open Circuit Conditions (OCC). With a commercialized GORE(TM) PRIMEA RTM 5631 MEAs at 70°C, data were obtained utilizing a material balance technique, which uses an ion selective electrode (ISE) to determine the concentration of ammonium ion in the process streams. The results indicate that ammonia is not transported across the membrane when the feeds to both electrodes are dry. However, with humidified feeds ammonia was transported from the anode to the cathode. The data also indicate the water content of in the MEA is the critical factor that causes NH3 crossover in the MEA. Diffusion coefficients of NH3 in MEA are also calculated at different relative humilities. An ERE was developed for PEM fuel cell by using a NafionRTM strip which was used to understand contamination mechanism. The voltage of anode electrode relative to ERE was measured during a polarization curve. The data showed the measurement of individual electrode potential was extremely affected by the misalignment between two electrodes. We compare the overpotential measured from the reference electrode and the calculated overpotential from subtracting the cell voltages between neat hydrogen and a 25 ppm CO in H 2 stream at same current. The studies indicated that the overpotentials obtained from

Influence of longer dry seasons in the Southern Amazon on patterns of water vapor transport over northern South America and the Caribbean

NASA Astrophysics Data System (ADS)

Agudelo, Jhoana; Arias, Paola A.; Vieira, Sara C.; Martínez, J. Alejandro

2018-06-01

Several studies have identified a recent lengthening of the dry season over the southern Amazon during the last three decades. Some explanations to this lengthening suggest the influence of changes in the regional circulation over the Atlantic and Pacific oceans, whereas others point to the influence of vegetation changes over the Amazon rainforest. This study aims to understand the implications of more frequent long dry seasons in this forest on atmospheric moisture transport toward northern South America and the Caribbean region. Using a semi-Langrangian model for water vapor tracking, results indicate that longer dry seasons in the southern Amazon relate to reductions of water vapor content over the southern and eastern Amazon basin, due to significant reductions of evaporation and recycled precipitation rates in these regions, especially during the transition from dry to wet conditions in the southern Amazon. On the other hand, longer dry seasons also relate to enhanced atmospheric moisture content over the Caribbean and northern South America regions, mainly due to increased contributions of water vapor from oceanic regions and the increase of surface moisture convergence over the equatorial region. This highlights the importance of understanding the relative role of regional circulation and local surface conditions on modulating water vapor transport toward continental regions.

Preliminary analysis of aircraft fuel systems for use with broadened specification jet fuels

NASA Technical Reports Server (NTRS)

Pasion, A. J.; Thomas, I.

1977-01-01

An analytical study was conducted on the use of broadened specification hydrocarbon fuels in present day aircraft. A short range Boeing 727 mission and three long range Boeing 747 missions were used as basis of calculation for one-day-per-year extreme values of fuel loading, airport ambient and altitude ambient temperatures with various seasonal and climatic conditions. Four hypothetical fuels were selected; two high-vapor-pressure fuels with 35 kPa and 70 kPa RVP and two high-freezing-point fuels with -29 C and -18 C freezing points. In-flight fuel temperatures were predicted by Boeing's aircraft fuel tank thermal analyzer computer program. Boil-off rates were calculated for the high vapor pressure fuels and heating/insulation requirements for the high freezing point fuels were established. Possible minor and major heating system modifications were investigated with respect to heat output, performance and economic penalties for the high freezing point fuels.

Hybrid life-cycle assessment of natural gas based fuel chains for transportation.

PubMed

Strømman, Anders Hammer; Solli, Christian; Hertwich, Edgar G

2006-04-15

This research compares the use of natural gas, methanol, and hydrogen as transportation fuels. These three fuel chains start with the extraction and processing of natural gas in the Norwegian North Sea and end with final use in Central Europe. The end use is passenger transportation with a sub-compact car that has an internal combustion engine for the natural gas case and a fuel cell for the methanol and hydrogen cases. The life cycle assessment is performed by combining a process based life-cycle inventory with economic input-output data. The analysis shows that the potential climate impacts are lowest for the hydrogen fuel scenario with CO2 deposition. The hydrogen fuel chain scenario has no significant environmental disadvantage compared to the other fuel chains. Detailed analysis shows that the construction of the car contributes significantly to most impact categories. Finally, it is shown how the application of a hybrid inventory model ensures a more complete inventory description compared to standard process-based life-cycle assessment. This is particularly significant for car construction which would have been significantly underestimated in this study using standard process life-cycle assessment alone.

Overview of the vapor generation and analysis parameters of the petroleum- and shale-derived fuel studies conducted in thomas dome exposure chambers at the toxic hazards research unit, Wright-Patterson Air Force Base (Dayton), Ohio, 1973-1983. Final report, January 1973-December 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leahy, H.F.

1994-05-01

Over a decade ago (1973-1983), a series of long-term inhalation exposures were performed to study the toxicity of a number of aviation and marine fuels derived from petroleum and compare results with those derived from shale. These included JP-4, JP-5, and diesel fuel marine, as well as some specialty petroleum derived fuels W-7, JP-8, and JP-TS. The Thomas Domes located in the Armstrong Laboratory at Wright-Patterson Air Force Base (Dayton), Ohio, were ideally suited for these studies because of both the large capacity for inhalation exposure of the mixed animal complement and the convenience of entry without interrupting continuous exposures.more » The target total hydrocarbon (TH) concentrations ranged from 0.05 to 5.0 mg/L. The concentration levels of TH vapors were limited by the effective vapor pressure of the type of fuel and, if exceeded, the formation of condensate aerosols in the exposure chamber. The Th vapor generation and analytical equipment is described. Advances in gas chromatographic technology during the period covered provided a variety of qualitative pictures of the fuel, vapor, and waste TH components. Hydrocarbons above C14 existed only in very low concentrations in any of the vapors.« less

Numerical simulation of proton exchange membrane fuel cells at high operating temperature

NASA Astrophysics Data System (ADS)

Peng, Jie; Lee, Seung Jae

A three-dimensional, single-phase, non-isothermal numerical model for proton exchange membrane (PEM) fuel cell at high operating temperature (T ≥ 393 K) was developed and implemented into a computational fluid dynamic (CFD) code. The model accounts for convective and diffusive transport and allows predicting the concentration of species. The heat generated from electrochemical reactions, entropic heat and ohmic heat arising from the electrolyte ionic resistance were considered. The heat transport model was coupled with the electrochemical and mass transport models. The product water was assumed to be vaporous and treated as ideal gas. Water transportation across the membrane was ignored because of its low water electro-osmosis drag force in the polymer polybenzimidazole (PBI) membrane. The results show that the thermal effects strongly affect the fuel cell performance. The current density increases with the increasing of operating temperature. In addition, numerical prediction reveals that the width and distribution of gas channel and current collector land area are key optimization parameters for the cell performance improvement.

Vapor core propulsion reactors

NASA Technical Reports Server (NTRS)

Diaz, Nils J.

1991-01-01

Many research issues were addressed. For example, it became obvious that uranium tetrafluoride (UF4) is a most preferred fuel over uranium hexafluoride (UF6). UF4 has a very attractive vaporization point (1 atm at 1800 K). Materials compatible with UF4 were looked at, like tungsten, molybdenum, rhenium, carbon. It was found that in the molten state, UF4 and uranium attacked most everything, but in the vapor state they are not that bad. Compatible materials were identified for both the liquid and vapor states. A series of analyses were established to determine how the cavity should be designed. A series of experiments were performed to determine the properties of the fluid, including enhancement of the electrical conductivity of the system. CFD's and experimental programs are available that deal with most of the major issues.

Technologies and Concepts for Reducing the Fuel Burn of Subsonic Transport Aircraft

NASA Technical Reports Server (NTRS)

Nickol, Craig L.

2012-01-01

There are many technologies under development that have the potential to enable large fuel burn reductions in the 2025 timeframe for subsonic transport aircraft relative to the current fleet. This paper identifies a potential technology suite and analyzes the fuel burn reduction potential of these technologies when integrated into advanced subsonic transport concepts. Advanced tube-and-wing concepts are developed in the single aisle and large twin aisle class, and a hybrid-wing-body concept is developed for the large twin aisle class. The resulting fuel burn reductions for the advanced tube-and-wing concepts range from a 42% reduction relative to the 777-200 to a 44% reduction relative to the 737-800. In addition, the hybrid-wingbody design resulted in a 47% fuel burn reduction relative to the 777-200. Of course, to achieve these fuel burn reduction levels, a significant amount of technology and concept maturation is required between now and 2025. A methodology for capturing and tracking concept maturity is also developed and presented in this paper.

Encouraging School Transportation Effective Energy Management (ESTEEM). Fuel Economy Management Handbook for Directors of Pupil Transportation; School District Administrators; Transportation Department Management.

ERIC Educational Resources Information Center

BRI Systems, Inc., Phoenix, AZ.

This handbook offers a practical approach for pupil transportation energy management by suggesting ideas to save fuel in the purchasing, planning, routing, scheduling, driving, and maintenance areas of the pupil transportation operation. The handbook is divided into seven parts. Part 1 and 2 provide insight into energy management in pupil…

The control of purity and stoichiometry of compound semiconductors by high vapor pressure transport

NASA Technical Reports Server (NTRS)

Bachmann, Klaus J.; Ito, Kazufumi; Scroggs, Jeffery S.; Tran, Hien T.

1995-01-01

In this report we summarize the results of a three year research program on high pressure vapor transport (HPVT) of compound semiconductors. Most of our work focused onto pnictides, in particular ZnGeP2, as a model system. Access to single crystals of well controlled composition of this material is desired for advancing the understanding and control of its point defect chemistry in the contest of remote, real-time sensing of trace impurities, e.g., greenhouse gases, in the atmosphere by ZnGeP2 optical parametric oscillators (OPO's).

Analyses on Water Vapor Resource in Chengdu City

NASA Astrophysics Data System (ADS)

Liu, B.; Xiao, T.; Wang, C.; Chen, D.

2017-12-01

Chengdu is located in the Sichuan basin, and it is the most famous inland city in China. With suitable temperatures and rainfall, Chengdu is the most livable cities in China. With the development of urban economy and society, the population has now risen to 16 million, and it will up to 22 million in 2030. This will cause the city water resources demand, and the carrying capacity of water resources become more and more serious. In order to improve the contradiction between urban waterlogging and water shortage, sponge city planning was proposed by Chengdu government, and this is of great practical significance for promoting the healthy development of the city. Base on the reanalysis data from NCEP during 2007-2016, the characters of Water Vapor Resources was analyzed, and the main contents of this research are summarized as follows: The water vapor resource in Chengdu plain is more than that in Southeast China and less in Northwest China. The annual average water vapor resource is approximately 160 mm -320 mm, and the water vapor resource in summer can reach 3 times in winter. But the annual average precipitation in Chengdu is about 800 mm -1200 mm and it is far greater than the water vapor resource, this is because of the transport of water vapor. Using the formula of water vapor flux, the water vapor in Chengdu is comes from the west and the south, and the value is around 50kg/(ms). Base on the calculation of boundary vapor budget, the water vapor transport under 500hPa accounted for 97% of the total. Consider the water vapor transport, transformation and urban humidification effect, the Water Vapor Resource in Chengdu is 2500mm, and it can be used by artificial precipitation enhancement. Therefore, coordinated development of weather modification and sponge city construction, the shortage of water resources in Chengdu plain can be solved. Key words: Chengdu; Sponge city; Water vapor resource; Precipitation; Artificial precipitation enhancement Acknowledgements

Simultaneous in situ Optical Monitoring Techniques during Crystal Growth of ZnSe by Physical Vapor Transport

NASA Technical Reports Server (NTRS)

Su, C.- H.; Feth, S.; Lehoczky, S. L.

1998-01-01

ZnSe crystals grown in sealed ampoules by the physical vapor transport method were monitored in situ using three techniques, simultaneously. A Michelson interferometer was set-up to observe the growth rate and surface morphological evolution. An interference pattern (interferogram) is formed by the interaction between the reflection of a HeNe laser (632.8 nm wavelength) off the crystal-vapor interface and a reference beam from the same laser. Preliminary results indicate that the rate of growth/thermal-etching can be calculated using analog data acquisition and simple fringe counting techniques. Gross surface features may also be observed using a digital frame grabber and fringe analysis software. The second in situ technique uses optical absorption to determine the partial pressures of the vapor species. The Se2 and Zn vapor species present in the sealed ampoule absorb light at characteristic wavelengths. The optical absorption is determined by monitoring the light intensity difference between the sample and reference beams. The Se2 Partial pressure profile along the length of the ampoule was estimated from the vibronic absorption peaks at 340.5, 350.8, 361.3 and 379.2 nm using the Beer's law constants established in the calibration runs of pure Se. Finally, because the high temperature crystal growth furnace contains windows, in situ visual observation of the growing crystal is also possible. The use of these techniques not only permits in situ investigation of high temperature vapor growth of semiconductors, but also offers the potential for real time feed back on the growing crystal and allows the possibility of actively controlling the growth process.

Origin of sulfide replacement textures in lunar breccias. Implications for vapor element transport in the lunar crust

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shearer, C.K.; Burger, P.V.; Guan, Y.

Lunar samples 67016,294, 67915,150, and 67016,297 represent clasts of Mg-suite and ferroan anorthosite lithologies that have interacted with a S-rich vapor. Numerous studies have speculated on the composition and source of these 'fluids', their capability for the transport of vapor-mobilized elements, and the scale and environment under which these types of process occurred. These models all assumed a Moon with a very 'dry' mantle, crust, and surface. The olivine in these lithologies is partially to totally replaced by troilite and low-Ca pyroxene. The troilite makes up 30-54 vol% of the troilite + low-Ca pyroxene pseudomorphs after olivine. Other silicates andmore » oxides in the assemblages have experienced post-magmatic reequilibration (pyroxene exsolution, recrystallization, 'exsolution' of ilmenite in spinel). The troilite also occurs in veins cross cutting individual phases and metamorphic textures. The sulfide veining and replacement features are restricted to individual clasts and do not cut across the matrix surrounding the clasts, and thus predate the breccia-forming event. The proportion of troilite to low-Ca pyroxene and silicate chemistries indicate that simple reactions (such as olivine + S{sub 2} {leftrightarrow} low-Ca pyroxene + troilite + O{sub 2}) do not adequately represent the replacement process. The sulfides have compositions that are similar to those found in mare basalts. In particular, the sulfides generally are enriched in Co relative to Ni. Exsolution of Ni-Co-Cu in the sulfides is distinctly different between the breccias and mare basalts and suggests a different cooling or crystallization (melt versus vapor) history. The sulfur isotopic composition of the vein and replacement troilite ranges from approximately {delta}{sup 34}S = -1.0{per_thousand} to -3.3{per_thousand}. Based on our observations, it appears that the model suggested by Norman et al. (1995) is the most appropriate for the origin of the troilite veining and troilite

Alternative Fuels Data Center: Wisconsin Transportation Data for

Science.gov Websites

Compressed Natural Gas (CNG) 41 15 Electric 249 36 Ethanol (E85) 189 1 Hydrogen 0 0 Liquefied Natural Gas Natural Gas Electricity Transportation Fuel Consumption Source: State Energy Data System based on beta ) 68,820 Natural Gas (million cubic feet) 400,877 Conventional Power Plants 76 Generating Capacity

10 CFR 51.52 - Environmental effects of transportation of fuel and waste-Table S-4.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Nuclear Power Plants,” WASH-1238, December 1972, and Supp. 1 NUREG-75/038 April 1975. Both documents are... 10 Energy 2 2010-01-01 2010-01-01 false Environmental effects of transportation of fuel and waste... Environmental effects of transportation of fuel and waste—Table S-4. Under § 51.50, every environmental report...

Auxiliary Electrodes for Chromium Vapor Sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fergus, Jeffrey; Shahzad, Moaiz; Britt, Tommy

Measurement of chromia-containing vapors in solid oxide fuel cell systems is useful for monitoring and addressing cell degradation caused by oxidation of the chomia scale formed on alloys for interconnects and balance-of-plant components. One approach to measuring chromium is to use a solid electrolyte with an auxiliary electrode that relates the partial pressure of the chromium containing species to the mobile species in the electrolyte. One example is YCrO3 which can equilibrate with the chromium containing vapor and yttrium in yttria stabilized zirconia to establish an oxygen activity. Another is Na2CrO4 which can equilibrate with the chromium-containing vapor to establishmore » a sodium activity.« less

Transportation Energy Futures Series: Alternative Fuel Infrastructure Expansion: Costs, Resources, Production Capacity, and Retail Availability for Low-Carbon Scenarios

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melaina, W.; Heath, Garvin; Sandor, Debra

2013-04-01

The petroleum-based transportation fuel system is complex and highly developed, in contrast to the nascent low-petroleum, low-carbon alternative fuel system. This report examines how expansion of the low-carbon transportation fuel infrastructure could contribute to deep reductions in petroleum use and greenhouse gas (GHG) emissions across the U.S. transportation sector. Three low-carbon scenarios, each using a different combination of low-carbon fuels, were developed to explore infrastructure expansion trends consistent with a study goal of reducing transportation sector GHG emissions to 80% less than 2005 levels by 2050.These scenarios were compared to a business-as-usual (BAU) scenario and were evaluated with respect tomore » four criteria: fuel cost estimates, resource availability, fuel production capacity expansion, and retail infrastructure expansion.« less

Neurobehavioral evaluations of rats gestationally exposed to gasoline vapors

EPA Science Inventory

As the US fuel supply is moving towards blends with higher ethanol levels, there are questions regarding effects of these fuel vapors in the developing fetus. As part of a project evaluating gasoline-ethanol blends of different proportions. we included an evaluation of inhaled pu...

Method of depositing a catalyst on a fuel cell electrode

DOEpatents

Dearnaley, Geoffrey; Arps, James H.

2000-01-01

Fuel cell electrodes comprising a minimal load of catalyst having maximum catalytic activity and a method of forming such fuel cell electrodes. The method comprises vaporizing a catalyst, preferably platinum, in a vacuum to form a catalyst vapor. A catalytically effective amount of the catalyst vapor is deposited onto a carbon catalyst support on the fuel cell electrode. The electrode preferably is carbon cloth. The method reduces the amount of catalyst needed for a high performance fuel cell electrode to about 0.3 mg/cm.sup.2 or less.

Fiber-Optic Determination of N2, O2, and Fuel Vapor in the Ullage of Liquid-Fuel Tanks

NASA Technical Reports Server (NTRS)

Nguyen, Quang-Viet

2008-01-01

A fiber-optic sensor system has been developed that can remotely measure the concentration of molecular oxygen (O2), nitrogen (N2), hydrocarbon vapor, and other gases (CO2, CO, H2O, chlorofluorocarbons, etc.) in the ullage of a liquid-fuel tank. The system provides an accurate and quantitative identification of the above gases with an accuracy of better than 1 percent by volume (for O2 or N2) in real-time (5 seconds). In an effort to prevent aircraft fuel tank fires or explosions similar to the tragic TWA Flight 800 explosion in 1996, OBIGGS are currently being developed for large commercial aircraft to prevent dangerous conditions from forming inside fuel tanks by providing an inerting gas blanket that is low in oxygen, thus preventing the ignition of the fuel/air mixture in the ullage. OBIGGS have been used in military aircraft for many years and are now standard equipment on some newer large commercial aircraft (such as the Boeing 787). Currently, OBIGGS are being developed for retrofitting to existing commercial aircraft fleets in response to pending mandates from the FAA. Most OBIGGS use an air separation module (ASM) that separates O2 from N2 to make nitrogen-enriched air from compressed air flow diverted from the engine (bleed air). Current OBIGGS systems do not have a closed-loop feedback control, in part, due to the lack of suitable process sensors that can reliably measure N2 or O2 and at the same time, do not constitute an inherent source of ignition. Thus, current OBIGGS operate with a high factor-of-safety dictated by process protocol to ensure adequate fuel-tank inerting. This approach is inherently inefficient as it consumes more engine bleed air than is necessary compared to a closed-loop controlled approach. The reduction of bleed air usage is important as it reduces fuel consumption, which translates to both increased flight range and lower operational costs. Numerous approaches to developing OBIGGS feedback-control sensors have been under

Tradable credits system design and cost savings for a national low carbon fuel standard for road transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rubin, Jonathan; Leiby, Paul N.

2012-06-11

This research examines the economic implications of different designs for a national low carbon fuel standard (NLCFS) for the road transportation sector. A NLCFS based on the average Carbon Intensity (CI) of all fuels sold in the gasoline and diesel markets will generate an incentive for fuel suppliers to reduce the measured CI of their petroleum fuels. The economic impacts of a NLCFS are fundamentally determined by: the availability of low carbon fuels; the compliance path; the reference level CI of the fuel baseline; and the degree of flexibility in the credit system. To quantitatively examine the implications of amore » NLCFS, we created the Transportation Regulation and Credit Trading (TRACT) Model. With TRACT, we model a NLCFS credit trading system among profit maximizing fuel suppliers for light- and heavy-duty vehicle fuel use for the United States from 2012 - 2030. Given the wide range of cost and availability of biofuels, we find that credit trading across gasoline and diesel fuel markets combined with credit banking can significantly reduce compliance costs and stabilize credit prices. We make policy recommendations on how to combine a NLCFS with other existing regulations for transportation fuels.« less

Nonradiative transport of atomic excitation in Na vapor

NASA Astrophysics Data System (ADS)

Zajonc, Arthur G.; Phelps, A. V.

1981-05-01

Measurements are reported which show the effect of nonradiative losses at a gas-window interface on the backscattered fluorescence intensity for Na vapor at frequencies in the vicinity of the resonance lines near 589 nm. The Na 3P12,32 states are excited with a low-intensity single-mode tunable dye laser at high Na densities and the frequency integral of the backscattered fluorescence intensity in the D1 and D2 lines is measured. As the laser is tuned through resonance, the loss of atomic excitation to the window appears as a sharp decrease in the frequency-integrated fluorescence intensity. For example, at 7×1020 atoms m-3 the fluorescence intensity decreases by a factor of 4 in a frequency interval of 4 GHz. Measured absolute fluorescence intensities versus laser frequency are compared with predictions made using the theory of Hummer and Kunasz which includes both radiative and nonradiative transport processes. The agreement between theory and experiment is remarkably good when one considers that the theory contains only one unknown coefficient, i.e., the reflection coefficient for excited atoms at the windows. In our case the excited atoms are assumed to be completely destroyed at the window.

Risk-Based Evaluation of Total Petroleum Hydrocarbons in Vapor Intrusion Studies

PubMed Central

Brewer, Roger; Nagashima, Josh; Kelley, Michael; Heskett, Marvin; Rigby, Mark

2013-01-01

This paper presents a quantitative method for the risk-based evaluation of Total Petroleum Hydrocarbons (TPH) in vapor intrusion investigations. Vapors from petroleum fuels are characterized by a complex mixture of aliphatic and, to a lesser extent, aromatic compounds. These compounds can be measured and described in terms of TPH carbon ranges. Toxicity factors published by USEPA and other parties allow development of risk-based, air and soil vapor screening levels for each carbon range in the same manner as done for individual compounds such as benzene. The relative, carbon range makeup of petroleum vapors can be used to develop weighted, site-specific or generic screening levels for TPH. At some critical ratio of TPH to a targeted, individual compound, the overwhelming proportion of TPH will drive vapor intrusion risk over the individual compound. This is particularly true for vapors associated with diesel and other middle distillate fuels, but can also be the case for low-benzene gasolines or even for high-benzene gasolines if an adequately conservative, target risk is not applied to individually targeted chemicals. This necessitates a re-evaluation of the reliance on benzene and other individual compounds as a stand-alone tool to evaluate vapor intrusion risk associated with petroleum. PMID:23765191

Methods of making transportation fuel

DOEpatents

Roes, Augustinus Wilhelmus Maria [Houston, TX; Mo, Weijian [Sugar Land, TX; Muylle, Michel Serge Marie [Houston, TX; Mandema, Remco Hugo [Houston, TX; Nair, Vijay [Katy, TX

2012-04-10

A method for producing alkylated hydrocarbons is disclosed. Formation fluid is produced from a subsurface in situ heat treatment process. The formation fluid is separated to produce a liquid stream and a first gas stream. The first gas stream includes olefins. The liquid stream is fractionated to produce at least a second gas stream including hydrocarbons having a carbon number of at least 3. The first gas stream and the second gas stream are introduced into an alkylation unit to produce alkylated hydrocarbons. At least a portion of the olefins in the first gas stream enhance alkylation. The alkylated hydrocarbons may be blended with one or more components to produce transportation fuel.

Explosive vapor detection payload for small robots

NASA Astrophysics Data System (ADS)

Stimac, Phil J.; Pettit, Michael; Wetzel, John P.; Haas, John W.

2013-05-01

Detection of explosive hazards is a critical component of enabling and improving operational mobility and protection of US Forces. The Autonomous Mine Detection System (AMDS) developed by the US Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate (NVESD) is addressing this challenge for dismounted soldiers. Under the AMDS program, ARA has developed a vapor sampling system that enhances the detection of explosive residues using commercial-off-the-shelf (COTS) sensors. The Explosives Hazard Trace Detection (EHTD) payload is designed for plug-and-play installation and operation on small robotic platforms, addressing critical Army needs for more safely detecting concealed or exposed explosives in areas such as culverts, walls and vehicles. In this paper, we describe the development, robotic integration and performance of the explosive vapor sampling system, which consists of a sampling "head," a vapor transport tube and an extendable "boom." The sampling head and transport tube are integrated with the boom, allowing samples to be collected from targeted surfaces up to 7-ft away from the robotic platform. During sample collection, an IR lamp in the sampling head is used to heat a suspected object/surface and the vapors are drawn through the heated vapor transport tube to an ion mobility spectrometer (IMS) for detection. The EHTD payload is capable of quickly (less than 30 seconds) detecting explosives such as TNT, PETN, and RDX at nanogram levels on common surfaces (brick, concrete, wood, glass, etc.).

High liquid fuel yielding biofuel processes and a roadmap for the future transportation

NASA Astrophysics Data System (ADS)

Singh, Navneet R.

In a fossil-fuel deprived world when crude oil will be scarce and transportation need cannot be met with electricity and transportation liquid fuel must be produced, biomass derived liquid fuels can be a natural replacement. However, the carbon efficiency of the currently known biomass to liquid fuel conversion processes ranges from 35-40%, yielding 90 ethanol gallon equivalents (ege) per ton of biomass. This coupled with the fact that the efficiency at which solar energy is captured by biomass (<1%) is significantly lower than H 2 (10-27%) and electricity (20-42%), implies that sufficient land area is not available to meet the need for the entire transportation sector. To counter this dilemma, a number of processes have been proposed in this work: a hybrid hydrogen-carbon (H2CAR) process based on biomass gasification followed by the Fischer-Tropsch process such that 100% carbon efficiency is achieved yielding 330 ege/ton biomass using hydrogen derived from a carbon-free energy. The hydrogen requirement for the H2CAR process is 0.33 kg/liter of diesel. To decrease the hydrogen requirement associated with the H2CAR process, a hydrogen bio-oil (H2Bioil) process based on biomass fast-hydropyrolysis/hydrodeoxygenation is proposed which can achieve liquid fuel yield of 215 ege/ton consuming 0.11 kg hydrogen per liter of oil. Due to the lower hydrogen consumption of the H2Bioil process, synergistically integrated transition pathways are feasible where hot syngas derived from coal gasification (H2Bioil-C) or a natural gas reformer (H 2Bioil-NG) is used to supply the hydrogen and process heat for the biomass fast-hydropyrolysis/hydrodeoxygenation. Another off-shoot of the H2Bioil process is the H2Bioil-B process, where hydrogen required for the hydropyrolysis is obtained from gasification of a fraction of the biomass. H2Bioil-B achieves the highest liquid fuel yield (126-146 ege/ton of biomass) reported in the literature for any self-contained conversion of biomass to

Nuclear design of a vapor core reactor for space nuclear propulsion

NASA Astrophysics Data System (ADS)

Dugan, Edward T.; Watanabe, Yoichi; Kuras, Stephen A.; Maya, Isaac; Diaz, Nils J.

1993-01-01

Neutronic analysis methodology and results are presented for the nuclear design of a vapor core reactor for space nuclear propulsion. The Nuclear Vapor Thermal Reactor (NVTR) Rocket Engine uses modified NERVA geometry and systems which the solid fuel replaced by uranium tetrafluoride vapor. The NVTR is an intermediate term gas core thermal rocket engine with specific impulse in the range of 1000-1200 seconds; a thrust of 75,000 lbs for a hydrogen flow rate of 30 kg/s; average core exit temperatures of 3100 K to 3400 K; and reactor thermal powers of 1400 to 1800 MW. Initial calculations were performed on epithermal NVTRs using ZrC fuel elements. Studies are now directed at thermal NVTRs that use fuel elements made of C-C composite. The large ZrC-moderated reactors resulted in thrust-to-weight ratios of only 1 to 2; the compact C-C composite systems yield thrust-to-weight ratios of 3 to 5.

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

DOEpatents

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.

Polymer electrolyte fuel cells: Potential transportation and stationary applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gottesfeld, S.

1993-01-01

The application of the polymer electrolyte fuel cell (PEFC) as a primary power source in electric vehicles has received increasing attention during the last few years. This increased attention is the result of a combination of significant technical advances in this fuel cell technology and the initiation of some projects for the demonstration of a complete, PEFC-based power system a bus or in a passenger car. Such demonstration projects reflect an increase in industry's faith in the potential of this technology for transportation applications, or, at least, in the need for a detailed evaluation of this potential. Nevertheless, large scalemore » transportation applications of PEFCs require a continued concerted effort of research on catalysis, materials and components, combined with the engineering efforts addressing the complete power system. This is required to achieve a cost effective, highly performing PEFC stack and power system. A related set of technical and cost challenges arises in the context of potential applications of PEFCs for stationary power applications, although there are clearly some differences in their nature, particularly, to do with the different types of fuels to be employed for each of these applications. We describe in this contribution some recent results of work performed by the Core Research PEFC Program at Los Alamos National Laboratory, which has addressed materials, components and single cell testing of PEFCS. Also included are some recent observations and some insights regarding the potential of this fuel cell technology for stationary Power generation.« less

Polymer electrolyte fuel cells: Potential transportation and stationary applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gottesfeld, S.

1993-04-01

The application of the polymer electrolyte fuel cell (PEFC) as a primary power source in electric vehicles has received increasing attention during the last few years. This increased attention is the result of a combination of significant technical advances in this fuel cell technology and the initiation of some projects for the demonstration of a complete, PEFC-based power system a bus or in a passenger car. Such demonstration projects reflect an increase in industry`s faith in the potential of this technology for transportation applications, or, at least, in the need for a detailed evaluation of this potential. Nevertheless, large scalemore » transportation applications of PEFCs require a continued concerted effort of research on catalysis, materials and components, combined with the engineering efforts addressing the complete power system. This is required to achieve a cost effective, highly performing PEFC stack and power system. A related set of technical and cost challenges arises in the context of potential applications of PEFCs for stationary power applications, although there are clearly some differences in their nature, particularly, to do with the different types of fuels to be employed for each of these applications. We describe in this contribution some recent results of work performed by the Core Research PEFC Program at Los Alamos National Laboratory, which has addressed materials, components and single cell testing of PEFCS. Also included are some recent observations and some insights regarding the potential of this fuel cell technology for stationary Power generation.« less

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.

Fuel conservation merits of advanced turboprop transport aircraft. Final report, January--August 1977

DOE Office of Scientific and Technical Information (OSTI.GOV)

Revell, J.D.; Tullis, R.H.

1977-08-01

The advantages of a propfan powered aircraft for the commercial air transportation system were assessed by the comparison with an equivalent turbofan transport. Comparisons were accomplished on the basis of fuel utilization and operating costs, as well as aircraft weight and size. Advantages of the propfan aircraft, concerning fuel utilization and operating costs, were accomplished by considering: (1) incorporation of propfan performance and acoustic data; (2) revised mission profiles (longer design range and reduction in; and cruise speed) (3) utilization of alternate and advanced technology engines.

Flux growth in a horizontal configuration: An analog to vapor transport growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, J. -Q.; Sales, B. C.; Susner, M. A.

Flux growth of single crystals is normally performed in a vertical configuration with an upright refractory container holding the flux melt. At high temperatures, flux dissolves the charge, forming a homogeneous solution before nucleation and growth of crystals takes place under proper supersaturation generated by cooling or evaporating the flux. In this paper, we report flux growth in a horizontal configuration with a temperature gradient along the horizontal axis: a liquid transport growth analogous to the vapor transport technique. In a typical liquid transport growth, the charge is kept at the hot end of the refractory container and the fluxmore » melt dissolves the charge and transfers it to the cold end. Once the concentration of charge is above the solubility limit at the cold end, the thermodynamically stable phase nucleates and grows. Compared to the vertical flux growth, the liquid transport growth can provide a large quantity of crystals in a single growth since the charge/flux ratio is not limited by the solubility limit at the growth temperature. This technique is complementary to the vertical flux growth and can be considered when a large amount of crystals is needed but the yield from the conventional vertical flux growth is limited. Finally, we applied this technique to the growth of IrSb 3, Mo 3Sb 7, and MnBi from self-flux, and the growth of FeSe, CrTe 3, NiPSe 3, FePSe 3, CuInP 2S 6, RuCl 3, and OsCl 4 from a halide flux.« less

Flux growth in a horizontal configuration: An analog to vapor transport growth

DOE PAGES

Yan, J. -Q.; Sales, B. C.; Susner, M. A.; ...

2017-07-05

Flux growth of single crystals is normally performed in a vertical configuration with an upright refractory container holding the flux melt. At high temperatures, flux dissolves the charge, forming a homogeneous solution before nucleation and growth of crystals takes place under proper supersaturation generated by cooling or evaporating the flux. In this paper, we report flux growth in a horizontal configuration with a temperature gradient along the horizontal axis: a liquid transport growth analogous to the vapor transport technique. In a typical liquid transport growth, the charge is kept at the hot end of the refractory container and the fluxmore » melt dissolves the charge and transfers it to the cold end. Once the concentration of charge is above the solubility limit at the cold end, the thermodynamically stable phase nucleates and grows. Compared to the vertical flux growth, the liquid transport growth can provide a large quantity of crystals in a single growth since the charge/flux ratio is not limited by the solubility limit at the growth temperature. This technique is complementary to the vertical flux growth and can be considered when a large amount of crystals is needed but the yield from the conventional vertical flux growth is limited. Finally, we applied this technique to the growth of IrSb 3, Mo 3Sb 7, and MnBi from self-flux, and the growth of FeSe, CrTe 3, NiPSe 3, FePSe 3, CuInP 2S 6, RuCl 3, and OsCl 4 from a halide flux.« less

Life cycle assessment of the production of hydrogen and transportation fuels from corn stover via fast pyrolysis

NASA Astrophysics Data System (ADS)

Zhang, Yanan; Hu, Guiping; Brown, Robert C.

2013-06-01

This life cycle assessment evaluates and quantifies the environmental impacts of the production of hydrogen and transportation fuels from the fast pyrolysis and upgrading of corn stover. Input data for this analysis come from Aspen Plus modeling, a GREET (Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation) model database and a US Life Cycle Inventory Database. SimaPro 7.3 software is employed to estimate the environmental impacts. The results indicate that the net fossil energy input is 0.25 MJ and 0.23 MJ per km traveled for a light-duty vehicle fueled by gasoline and diesel fuel, respectively. Bio-oil production requires the largest fossil energy input. The net global warming potential (GWP) is 0.037 kg CO2eq and 0.015 kg CO2eq per km traveled for a vehicle fueled by gasoline and diesel fuel, respectively. Vehicle operations contribute up to 33% of the total positive GWP, which is the largest greenhouse gas footprint of all the unit processes. The net GWPs in this study are 88% and 94% lower than for petroleum-based gasoline and diesel fuel (2005 baseline), respectively. Biomass transportation has the largest impact on ozone depletion among all of the unit processes. Sensitivity analysis shows that fuel economy, transportation fuel yield, bio-oil yield, and electricity consumption are the key factors that influence greenhouse gas emissions.

Study of LH2 fueled subsonic passenger transport aircraft

NASA Technical Reports Server (NTRS)

Brewer, G. D.; Morris, R. E.

1976-01-01

The potential of using liquid hydrogen as fuel in subsonic transport aircraft was investigated to explore an expanded matrix of passenger aircraft sizes. Aircraft capable of carrying 130 passengers 2,780 km (1500 n.mi.); 200 passengers 5,560 km (3000 n.mi.); and 400 passengers on a 9,265 km (5000 n.mi.) radius mission, were designed parametrically. Both liquid hydrogen and conventionally fueled versions were generated for each payload/range in order that comparisons could be made. Aircraft in each mission category were compared on the basis of weight, size, cost, energy utilization, and noise.

Minimum-fuel, three-dimensional flight paths for jet transports

NASA Technical Reports Server (NTRS)

Neuman, F.; Kreindler, E.

1985-01-01

A number of studies dealing with fuel minimization are concerned with three-dimensional flight. However, only Neuman and Kreindler (1982) consider cases involving commercial jet transports. In the latter study, only the climb-out and descent portions of complete long-range flight paths below 10,000 ft altitude have been investigated. The present investigation is concerned with the computation of minimum-fuel nonturning and turning flight paths for climb-outs from 2000 to 10,000 ft for long-range flights (greater than 50 n mi), and for complete flight paths of lengths between 5 and 50 n mi.

Observed Changes in Upper-Tropospheric Water Vapor Transport From Satellite Measurements During the Summers of 1987 and 1988

NASA Technical Reports Server (NTRS)

Lerner, Jeffrey A.; Jedlovee, Gary J.; Atkinson, Robert J.

1998-01-01

The research described below focuses on the use of satellite measurements to monitor both monthly and interannual changes in UT (upper tropospheric) water vapor transport. The GOES-7 Pathfinder data set is used to estimate both winds and humidity during the summers (JJA) of 1987 and 1988. These two summers are of particular importance to climate variability since they were characterized by a dramatic shift in the Southern Oscillation index (i.e., 1987 as a warm ENSO event and 1988 as a cold La-Nina period) (Arkin, 1988; Ropelewski 1988). The contrasting features of the summers of '87 and '88 are exploited to demonstrate the utility of satellite wind and humidity estimates to analyze the role of water vapor in climate change.

Final Report: Vapor Transport Deposition for Thin Film III-V Photovoltaics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boettcher, Shannon; Greenaway, Ann; Boucher, Jason

2016-02-10

Silicon, the dominant photovoltaic (PV) technology, is reaching its fundamental performance limits as a single absorber/junction technology. Higher efficiency devices are needed to reduce cost further because the balance of systems account for about two-thirds of the overall cost of the solar electricity. III-V semiconductors such as GaAs are used to make the highest-efficiency photovoltaic devices, but the costs of manufacture are much too high for non-concentrated terrestrial applications. The cost of III-V’s is driven by two factors: (1) metal-organic chemical vapor deposition (MOCVD), the dominant growth technology, employs expensive, toxic and pyrophoric gas-phase precursors, and (2) the growth substratesmore » conventionally required for high-performance devices are monocrystalline III-V wafers. The primary goal of this project was to show that close-spaced vapor transport (CSVT), using water vapor as a transport agent, is a scalable deposition technology for growing low-cost epitaxial III-V photovoltaic devices. The secondary goal was to integrate those devices on Si substrates for high-efficiency tandem applications using interface nanopatterning to address the lattice mismatch. In the first task, we developed a CSVT process that used only safe solid-source powder precursors to grow epitaxial GaAs with controlled n and p doping and mobilities/lifetimes similar to that obtainable via MOCVD. Using photoelectrochemical characterization, we showed that the best material had near unity internal quantum efficiency for carrier collection and minority carrier diffusions lengths in of ~ 8 μm, suitable for PV devices with >25% efficiency. In the second task we developed the first pn junction photovoltaics using CSVT and showed unpassivated structures with open circuit photovoltages > 915 mV and internal quantum efficiencies >0.9. We also characterized morphological and electrical defects and identified routes to reduce those defects. In task three we grew

Evaluating the viability of dimethyl carbonate as an alternative fuel for the transportation sector.

DOT National Transportation Integrated Search

2017-06-01

Some of the most important questions in the development of sustainable transportation are : identify fuels that will reduce emissions, provide diversification from fossil fuels, reduce : greenhouse gas emissions, be produced from renewable sources, a...

Invisible transportation infrastructure technology to mitigate energy and environment.

PubMed

Hossain, Md Faruque

2017-01-01

Traditional transportation infrastructure built by heat trapping products and the transportation vehiles run by fossil fuel, both causing deadly climate change. Thus, a new technology of invisible Flying Transportation system has been proposed to mitigate energy and environmental crisis caused by traditional infrastructure system. Underground Maglev system has been modeled to be constructed for all transportation systems to run the vehicle smoothly just over two feet over the earth surface by propulsive and impulsive force at flying stage. A wind energy modeling has also been added to meet the vehicle's energy demand when it runs on a non-maglev area. Naturally, all maglev infrastructures network to be covered by evergreen herb except pedestrian walkways to absorb CO 2 , ambient heat, and moisture (vapor) from the surrounding environment to make it cool. The research revealed that the vehicle will not require any energy since it will run by superconducting electromagnetic force while it runs on a maglev infrastructure area and directed by wind energy while it runs on non-maglev area. The proposed maglev transportation infrastructure technology will indeed be an innovative discovery in modern engineering science which will reduce fossil fuel energy consumption and climate change dramatically.

49 CFR 193.2059 - Flammable vapor-gas dispersion protection.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Flammable vapor-gas dispersion protection. 193.2059 Section 193.2059 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE...

Life-cycle assessment of diesel, natural gas and hydrogen fuel cell bus transportation systems

NASA Astrophysics Data System (ADS)

Ally, Jamie; Pryor, Trevor

The Sustainable Transport Energy Programme (STEP) is an initiative of the Government of Western Australia, to explore hydrogen fuel cell technology as an alternative to the existing diesel and natural gas public transit infrastructure in Perth. This project includes three buses manufactured by DaimlerChrysler with Ballard fuel cell power sources operating in regular service alongside the existing natural gas and diesel bus fleets. The life-cycle assessment (LCA) of the fuel cell bus trial in Perth determines the overall environmental footprint and energy demand by studying all phases of the complete transportation system, including the hydrogen infrastructure, bus manufacturing, operation, and end-of-life disposal. The LCAs of the existing diesel and natural gas transportation systems are developed in parallel. The findings show that the trial is competitive with the diesel and natural gas bus systems in terms of global warming potential and eutrophication. Emissions that contribute to acidification and photochemical ozone are greater for the fuel cell buses. Scenario analysis quantifies the improvements that can be expected in future generations of fuel cell vehicles and shows that a reduction of greater than 50% is achievable in the greenhouse gas, photochemical ozone creation and primary energy demand impact categories.

What is the role of laminar cirrus cloud on regulating the cross-tropopause water vapor transport?

NASA Astrophysics Data System (ADS)

Wu, D. L.; Gong, J.; Tsai, V.

2016-12-01

Laminar cirrus is an extremely thin ice cloud found persistently inhabit in the tropical and subtropical tropopause. Due to its sub-visible optical depth and high formation altitude, knowledge about the characteristics of this special type of cloud is very limited, and debates are ongoing about its role on regulating the cross-tropopause transport of water vapor. The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the CALIPSO satellite has been continuously providing us with unprecedented details of the laminar cirrus since its launch in 2006. In this research, we adapted Winker and Trepte (1998)'s eyeball detection method. A JAVA-based applet and graphical user interface (GUI) is developed to manually select the laminar, which then automatically record the cloud properties, such as spatial location, shape, thickness, tilt angle, and whether its isolated or directly above a deep convective cloud. Monthly statistics of the laminar cirrus are then separately analyzed according to the orbit node, isolated/convective, banded/non-banded, etc. Monthly statistics support a diurnal difference in the occurring frequency and formation height of the laminar cirrus. Also, isolated and convective laminars show diverse behaviors (height, location, distribution, etc.), which strongly implies that their formation mechanisms and their roles on depleting the upper troposphere water vapor are distinct. We further study the relationship between laminar characteristics and collocated and coincident water vapor gradient measurements from Aura Microwave Limb Sounder (MLS) observations below and above the laminars. The identified relationship provides a quantitative answer to the role laminar cirrus plays on regulating the water vapor entering the stratosphere.

Model for the Vaporization of Mixed Organometallic Compounds in the Metalorganic Chemical Vapor Deposition of High Temperature Superconducting Films

NASA Technical Reports Server (NTRS)

Meng, Guangyao; Zhou, Gang; Schneider, Roger L.; Sarma, Bimal K.; Levy, Moises

1993-01-01

A model of the vaporization and mass transport of mixed organometallics from a single source for thin film metalorganic chemical vapor deposition is presented. A stoichiometric gas phase can be obtained from a mixture of the organometallics in the desired mole ratios, in spite of differences in the volatilities of the individual compounds. Proper film composition and growth rates are obtained by controlling the velocity of a carriage containing the organometallics through the heating zone of a vaporizer.

Lattice Boltzmann modeling of transport phenomena in fuel cells and flow batteries

NASA Astrophysics Data System (ADS)

Xu, Ao; Shyy, Wei; Zhao, Tianshou

2017-06-01

Fuel cells and flow batteries are promising technologies to address climate change and air pollution problems. An understanding of the complex multiscale and multiphysics transport phenomena occurring in these electrochemical systems requires powerful numerical tools. Over the past decades, the lattice Boltzmann (LB) method has attracted broad interest in the computational fluid dynamics and the numerical heat transfer communities, primarily due to its kinetic nature making it appropriate for modeling complex multiphase transport phenomena. More importantly, the LB method fits well with parallel computing due to its locality feature, which is required for large-scale engineering applications. In this article, we review the LB method for gas-liquid two-phase flows, coupled fluid flow and mass transport in porous media, and particulate flows. Examples of applications are provided in fuel cells and flow batteries. Further developments of the LB method are also outlined.

High speed commercial transport fuels considerations and research needs

NASA Technical Reports Server (NTRS)

Lee, C. M.; Niedzwiecki, R. W.

1989-01-01

NASA is currently evaluating the potential of incorporating High Speed Civil Transport (HSCT) aircraft in the commercial fleet in the beginning of the 21st century. NASA sponsored HSCT enabling studies currently underway with airframers and engine manufacturers, are addressing a broad range of technical, environmental, economic, and related issues. Supersonic cruise speeds for these aircraft were originally focused in the Mach 2 to 5 range. At these flight speeds, both jet fuels and liquid methane were considered potential fuel candidates. For the year 2000 to 2010, cruise Mach numbers of 2 to 3+ are projected for aircraft fuel with thermally stable liquid jet fuels. For 2015 and beyond, liquid methane fueled aircraft cruising at Mach numbers of 4+ may be viable candidates. Operation at supersonic speeds will be much more severe than those encountered at subsonic flight. One of the most critical problems is the potential deterioration of the fuel due to the high temperature environment. HSCT fuels will not only be required to provide the energy necessary for flight, but will also be subject to aerodynamic heating and, will be required to serve as the primary heat sink for cooling the engine and airframe. To define fuel problems for high speed flight, a fuels workshop was conducted at NASA Lewis Research Center. The purpose of the workshop was to gather experts on aviation fuels, airframe fuel systems, airport infrastructure, and combustion systems to discuss high speed fuel alternatives, fuel supply scenarios, increased thermal stability approaches and measurements, safety considerations, and to provide directional guidance for future R and D efforts. Subsequent follow-up studies defined airport infrastructure impacts of high speed fuel candidates. The results of these activities are summarized. In addition, an initial case study using modified in-house refinery simulation model Gordian code (1) is briefly discussed. This code can be used to simulate different

Alternative Fuels Data Center: West Virginia Transportation Data for

Science.gov Websites

Transportation Fuel Consumption Source: State Energy Data System based on beta data converted to gasoline gallon (bbl/day) 20,000 Renewable Power Plants 13 Renewable Power Plant Capacity (nameplate, MW) 751 Source Source: Average prices per gasoline gallon equivalent (GGE) for the Lower Atlantic PADD from the

Environmental and financial implications of ethanol as a bioethylene feedstock versus as a transportation fuel

NASA Astrophysics Data System (ADS)

McKechnie, Jon; Pourbafrani, Mohammad; Saville, Bradley A.; MacLean, Heather L.

2015-12-01

Bulk chemicals production from biomass may compete with biofuels for low-cost and sustainable biomass sources. Understanding how alternative uses of biomass compare in terms of financial and environmental parameters is therefore necessary to help ensure that efficient uses of resources are encouraged by policy and undertaken by industry. In this paper, we compare the environmental and financial performance of using ethanol as a feedstock for bioethylene production or as a transport fuel in the US life cycle-based models are developed to isolate the relative impacts of these two ethanol uses and generate results that are applicable irrespective of ethanol production pathway. Ethanol use as a feedstock for bioethylene production or as a transport fuel leads to comparable greenhouse gas (GHG) emissions and fossil energy consumption reductions relative to their counterparts produced from fossil sources. By displacing gasoline use in vehicles, use of ethanol as a transport fuel is six times more effective in reducing petroleum energy use on a life cycle basis. In contrast, bioethylene predominately avoids consumption of natural gas. Considering 2013 US ethanol and ethylene market prices, our analysis shows that bioethylene is financially viable only if significant price premiums are realized over conventional ethylene, from 35% to 65% depending on the scale of bioethylene production considered (80 000 t yr-1 to 240 000 t yr-1). Ethanol use as a transportation fuel is therefore the preferred pathway considering financial, GHG emissions, and petroleum energy use metrics, although bioethylene production could have strategic value if demand-side limitations of ethanol transport fuel markets are reached.

Transportation Energy Futures Series: Alternative Fuel Infrastructure Expansion: Costs, Resources, Production Capacity, and Retail Availability for Low-Carbon Scenarios

DOE Office of Scientific and Technical Information (OSTI.GOV)