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1

LNG Vapor Dispersion Prediction with the DEGADIS Dense Gas Dispersion Model. Topical Report, April 1988-July 1990. Documentation.  

National Technical Information Service (NTIS)

The topical report is one of a series on the development of methods for LNG vapor dispersion prediction for regulatory application. The results indicate that the DEGADIS model is superior both phenomenologically and in performance to the Gaussian line sou...

J. Havens T. Spicer

1990-01-01

2

LNG Vapor Dispersion Prediction with the DEGADIS Dense Gas Dispersion Model (for Microcomputers).  

National Technical Information Service (NTIS)

The DEGADIS model is consistent with a wide range of laboratory and field test data for dense gas releases on a flat surface with dispersion over unobstructed flat terrain. Comparisons indicate that the DEGADIS model is superior in performance to the Gaus...

1991-01-01

3

LNG fire and vapor control system technologies  

Microsoft Academic Search

This report provides a review of fire and vapor control practices used in the liquefied natural gas (LNG) industry. Specific objectives of this effort were to summarize the state-of-the-art of LNG fire and vapor control; define representative LNG facilities and their associated fire and vapor control systems; and develop an approach for a quantitative effectiveness evaluation of LNG fire and

G. J. Konzek; K. M. Yasutake; A. L. Franklin

1982-01-01

4

Evaluation of 3-D hydrodynamic computer models for prediction of LNG vapor dispersion in the atmosphere. Annual report, March 1984-February 1985  

SciTech Connect

The MARIAH-II, SIGMET-N, ZEPHYR, and FEM3 3-D hydrodynamic computer models for atmospheric dispersion of LNG vapor are being evaluated. The models show important differences in the prediction of LNG vapor dispersion; the differences are attributed primarily to numerical diffusion and modeling of turbulent air entrainment. The importance of controlling numerical diffusion to prevent masking the physical diffusion is demonstrated. The turbulent air entrainment submodel used in MARIAH-II, SIGMET-N, and ZEPHYR is considered unsuitable for simulation of the general LNG dispersion scenario. An improved turbulent entrainment submodel is being developed, with initial testing against laboratory mixing experiment and wind tunnel data. Validation of models against controlled experiment data will precede comparison of simulations with a wide range of heavy gas field test data.

Havens, J.A.; Schreurs, P.J.

1985-03-01

5

Effects of high expansion foam dispersed onto leaked LNG on the atmospheric diffusion of vaporized gas  

Microsoft Academic Search

When LNG leaks from a storage tank, the LNG vapourizes vigorously above the adiabatic concrete floor inside the safety dike and the cryogenic methane diffuses in the atmosphere. It is well known that as the density of a vapourized gas drops, the atmospheric diffusion is enhanced due to buoyancy, and the concentration of vapourized gas along the ground decreases. The

K. Yoshida; K. Ogura

1996-01-01

6

LNG fire and vapor control system technologies  

SciTech Connect

This report provides a review of fire and vapor control practices used in the liquefied natural gas (LNG) industry. Specific objectives of this effort were to summarize the state-of-the-art of LNG fire and vapor control; define representative LNG facilities and their associated fire and vapor control systems; and develop an approach for a quantitative effectiveness evaluation of LNG fire and vapor control systems. In this report a brief summary of LNG physical properties is given. This is followed by a discussion of basic fire and vapor control design philosophy and detailed reviews of fire and vapor control practices. The operating characteristics and typical applications and application limitations of leak detectors, fire detectors, dikes, coatings, closed circuit television, communication systems, dry chemicals, water, high expansion foam, carbon dioxide and halogenated hydrocarbons are described. Summary descriptions of a representative LNG peakshaving facility and import terminal are included in this report together with typical fire and vapor control systems and their locations in these types of facilities. This state-of-the-art review identifies large differences in the application of fire and vapor control systems throughout the LNG industry.

Konzek, G.J.; Yasutake, K.M.; Franklin, A.L.

1982-06-01

7

Four band differential radiometer for monitoring LNG vapors  

NASA Technical Reports Server (NTRS)

The development by JPL of a four band differential radiometer (FBDR) which is capable of providing a fast rate of response, accurate measurements of methane, ethane, and propane concentrations on the periphery of a dispersing LNG cloud. The FBDR is a small, low power, lightweight, portable instrument system that uses differential absorption of near infrared radiation by the LNG cloud as a technique for the determination of concentration of the three gases as the LNG cloud passes the instrument position. Instrument design and data analysis approaches are described. The data obtained from the FBDR prototype instrument system deployed in an instrument array during two 40 cubic meter spill tests are discussed.

Simmonds, J. J.

1981-01-01

8

Boil-off gas vapors are recovered by reliquefaction in LNG  

Microsoft Academic Search

Although great care is taken to prevent heat leaks into cryogenic equipment in LNG terminals, boil-off vapors evolve from LNG stored at thermodynamic equilibrium. The quantities of boil-off vapors may be quite considerable. They account for about 1% of the total gas quantity received and sent out at the monitor-de-bretagne LNG terminal of Gaz de France. A novel process has

M. Levay; P. Petit; H. Paradowski

1986-01-01

9

Numerical simulation of the mitigating effects of an LNG vapor fence  

SciTech Connect

FEM3A, a fully three-dimensional numerical model for simulating the atmospheric dispersion of heavy gases involving complex geometry, has been used to investigate the mitigating effects of a vapor fence for LNG storage areas. In this paper, a brief description of the numerical model used to perform such calculations is given, the problem being simulated is described, and an intercomparison among the results from numerical simulations (with and without the vapor fence) and field data (with vapor fence) is made. The numerical results indicate that, with the present fence configuration, the maximum concentration on the cloud centerline was reduced by a factor of two or more within 250 m behind the fence, and the downwind distance to the 2.5% concentration was reduced from 365 m to 230 m. However, a vapor fence could also cause the vapor cloud to linger considerably longer in the source area, thus increasing the potential for ignition and combustion within the vapor fence and the area nearby over time. 8 refs., 10 figs.

Chan, S.T.

1990-05-01

10

Effects of Structures on Toxic Vapor Dispersion.  

National Technical Information Service (NTIS)

Currently available toxic vapor dispersion models at Air Force facilities do not adequately include the effects of structures on the rate of dispersion. Some relevant models and data sets are available in the literature as a result of research by other or...

L. L. Schulman S. R. Hanna R. Britter

1996-01-01

11

LNG measurement at Hopkinton plant  

Microsoft Academic Search

The Hopkinton LNG Corp. effectively uses turbine meters to measure the LNG vaporized from its LNG facility at Hopkinton, Mass., for peakshaving to serve customers of its parent companies, the New England Gas and Electric Association and Air Products and Chemicals, Inc., as well as NEGEA subsidiary Commonwealth Gas Co. The joint venture also includes the 500 million cf LNG

R. C. Farmer; E. J. Cooney

1974-01-01

12

Controlling the hazards from LNG spills on the ground; LNG firefighting methods and their effects; application to Gaz de France terminals  

Microsoft Academic Search

Gaz de France has developed a mathematical model to calculate vapor dispersion from accidental LNG spills on land. This model was applied to make clear the influence of certain parameters in reducing the extension of the plumes. Based on the results of calculations -provided that basic safety features were included in the design and building of the LNG facilities -

F. Bellus; H. Cochard; R. Vincent; J. Mauger

1978-01-01

13

Storage and regasification of liquefied natural gas (LNG)  

Microsoft Academic Search

A discussion covers the historical background of LNG; a description of Columbia LNG Corp.'s LNG terminal at Cove Point, Maryland, including physical plant layout; LNG unloading facilities; the primary vaporization system, which uses submerged combustion to vaporize approximately 75% of the LNG; waste heat LNG vaporizers; four 375,000 bbl aluminum, double-wall storage tanks; the centrifugal, single-stage, pot-mounted LNG pumps; safety

Litchfield

1980-01-01

14

Controlling the Hazards from LNG Spills on the Ground, LNG Firefighting Methods and Their Effects Application to Gas de France Terminals.  

National Technical Information Service (NTIS)

Gaz de France has developed a mathematical model to calculate vapor dispersion from accidental LNG spills on land. This model has been applied to make clear the influence of certain parameters in reducing the extension of the plumes. Based on the results ...

F. Bellus H. Cochard J. Mauger R. Vincent

1978-01-01

15

46 CFR 154.1854 - Methane (LNG) as fuel.  

Code of Federal Regulations, 2010 CFR

...LNG) as fuel. (a) If methane (LNG) vapors are used...States. (b) When the methane (LNG) fuel supply is shut...to loss of ventilation or detection of gas, the master shall ensure that the methane (LNG) fuel supply is...

2009-10-01

16

46 CFR 154.1854 - Methane (LNG) as fuel.  

Code of Federal Regulations, 2010 CFR

...LNG) as fuel. (a) If methane (LNG) vapors are used...States. (b) When the methane (LNG) fuel supply is shut...to loss of ventilation or detection of gas, the master shall ensure that the methane (LNG) fuel supply is...

2010-10-01

17

Chemical vapor infiltration: Dispersed and graded depositions for ceramic composites  

Microsoft Academic Search

A structured-geometry model for dispersed and graded deposits was developed for chemical vapor infiltration of multiply-woven substrates of carbon filters. An earlier model was modified to allow for two reactants in the feed. The model predicts gas-phase concentration profiles in the voids of substrates and deposition amounts of two reactants as a function of time and location. Results are shown

G. Y. Chung; B. J. McCoy; J. M. Smith; Domenick E. Cagliostro

1993-01-01

18

49 CFR 193.2059 - Flammable vapor-gas dispersion protection.  

Code of Federal Regulations, 2011 CFR

...order to account for additional cloud dilution which may be caused...parameters must be used in computing dispersion distances: ...upwind and downwind of the vapor cloud has dense vegetation and that the vapor cloud height is more than ten...

2011-10-01

19

Liquid turbines improve LNG operations  

Microsoft Academic Search

Adding a pair of cryogenic hydraulic turbines, often called liquid expanders, into an LNG processing train can increase plant annual revenues by 3--4%. The cooldown of a vapor phase by expansion through a gas turbine is widely used in such cryogenic processes as NGL and LPG recovery in the cold section of the steam cracking and in air or natural-gas

L. L. Johnson; G. Renaudin

1996-01-01

20

49 CFR 193.2059 - Flammable vapor-gas dispersion protection.  

Code of Federal Regulations, 2013 CFR

... Flammable vapor-gas dispersion protection...Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS...TRANSPORTATION (CONTINUED) PIPELINE SAFETY LIQUEFIED NATURAL GAS FACILITIES: FEDERAL...Accident Consequence Analysesâ. The use of...

2013-10-01

21

Type curves to determine the relative importance of advection and dispersion for solute and vapor transport  

Microsoft Academic Search

The relative importance of advection and dispersion for both solute and vapor transport can be determined from type curves for concentration, flux, or cumulative flux. The dimensionless form of the type curves provides a means to directly evaluate the importance of mass transport by advection relative to that of mass transport by diffusion and dispersion. Type curves based on an

John A. Garges; Arthur L. Baehr

1998-01-01

22

Cove Point: A step back into the LNG business  

Microsoft Academic Search

In 1978, ships began unloading LNG from Algeria at Cove Point`s berthing facilities 1.25 miles offshore. An underwater pipeline transported the LNG to land, where it was stored in the terminal`s four 140-foot-high cryogenic storage tanks. When the LNG was needed, the terminals 10 vaporizers converted it back to gas for send out via an 87-mile-long, 36-inch-diameter pipeline linking the

Katz

1995-01-01

23

LNG report\\/Dryout, cooldown keyed Cove Point commissioning  

Microsoft Academic Search

Columbia LNG Corp.'s experiences in commissioning its Cove Point, Md., terminal are described in some detail, including the dryout of all cryogenic vessels, piping, and equipment after field pressure testing, with nitrogen as the dryout medium; the initial cooldown to test and inspect the 14 and 32 in. dia vapor and LNG lines, pipe supports, and bellow-type expansion joints for

Venendaal

1979-01-01

24

A novel cryogenic power cycle for LNG cold energy recovery  

Microsoft Academic Search

A novel cryogenic cycle by using a binary mixture as working fluids and combined with a vapor absorption process was proposed to improve the energy recovery efficiency of an LNG (liquefied natural gas) cold power generation. The cycle was simulated with seawater as the heat source and LNG as the heat sink, and the optimization of the power generated per

Yanni Liu; Kaihua Guo

2011-01-01

25

Simultaneous chemical vapor deposition of SiC-dispersed phase composites  

SciTech Connect

Ceramic composites are being developed because they can have high strength and toughness yet retain the normal ceramic attributes of refractoriness and high resistance to abrasion and corrosion. In the present research, toughened ceramic composites were produced by the simultaneous chemical vapor deposition of an SiC matrix and a dispersed phase of TiSi/sub 2/. The morphology of the dispersed phase was found to control the mechanical properties of the composite. Deposition of coatings in a fluidized bed produced a finer and more uniformly dispersed second phase. The conditions within the fluidized bed such as temperature, gas composition, and hydrogen flow also affected the morphology of the TiSi/sub 2/ phase. The fracture toughness values for these composite coatings approached 5.5 MPa..sqrt..m at 25/sup 0/C, which is significantly higher than the toughness value for chemically vapor deposited SiC.

Stinton, D.P.; Lackey, W.J.

1985-01-01

26

Effect of filler dispersion on the electromechanical response of epoxy/vapor-grown carbon nanofiber composites  

NASA Astrophysics Data System (ADS)

The piezoresistive response of epoxy/vapor-grown carbon nanofiber composites prepared by four different dispersion methods achieving different dispersion levels has been investigated. The composite response was measured as a function of carbon nanofiber loading for the different dispersion methods. Strain sensing by variation of the electrical resistance was tested through four-point bending experiments, and the dependence of the gauge factor as a function of the deformation and velocity of deformation was calculated as well as the stability of the electrical response. The composites demonstrated an appropriate response for being used as a piezoresistive sensor. Specific findings were that the intrinsic piezoresistive response was only effective around the percolation threshold and that good cluster dispersion was more appropriate for a good piezoresistive response than a uniform dispersion of individual nanofibers. The application limits of these materials for sensor applications are also addressed.

Ferreira, A.; Cardoso, P.; Klosterman, D.; Covas, J. A.; van Hattum, F. W. J.; Vaz, F.; Lanceros-Mendez, S.

2012-07-01

27

Vaporization, dispersion, and radiant fluxes from LPG spills. Final technical report  

SciTech Connect

Both burning and non-burning spills of LPG (primarily propane) were studied. Vaporization rates for propane spills on soil, concrete, insulating concrete, asphalt, sod, wood, and polymer foams were measured. Thermal conductivity, heat transfer coefficients, and steady state vaporization rates were determined. Vapor concentrations were measured downwind of open propane pools and a Gaussian dispersion model modified for area sources provided a good correlation of measured concentrations. Emitted and incident radiant fluxes from propane fires were measured. Simplified flame radiation models were adequate for predicting radiant fluxes. Tests in which propane was sprayed into the air showed that at moderately high spray rates all the propane flashed to vapor or atomized; no liquid collected on the ground.

Not Available

1982-05-01

28

Curves to determine the relative importance of advection and dispersion for solute and vapor transport  

USGS Publications Warehouse

The relative importance of advection and dispersion for both solute and vapor transport can be determined from type curves or concentration, flux, or cumulative flux. The dimensionless form of the type curves provides a means to directly evaluate the importance of mass transport by advection relative to that of mass transport by diffusion and dispersion. Type curves based on an analytical solution to the advection-dispersion equation are plotted in terms of dimensionless time and Peclet number. Flux and cumulative flux type curves provide additional rationale for transport regime determination in addition to the traditional concentration type curves. The extension of type curves to include vapor transport with phase partitioning in the unsaturated zone is a new development. Type curves for negative Peclet numbers also are presented. A negative Peclet number characterizes a problem in which one direction of flow is toward the contamination source, and thereby diffusion and advection can act in opposite directions. Examples are the diffusion of solutes away from the downgradient edge of a pump-and-treat capture zone, the upward diffusion of vapors through the unsaturated zone with recharge, and the diffusion of solutes through a low hydraulic conductivity cutoff wall with an inward advective gradient.

Garges, J. A.; Baehr, A. L.

1998-01-01

29

Type curves to determine the relative importance of advection and dispersion for solute and vapor transport  

SciTech Connect

The relative importance of advection and dispersion for both solute and vapor transport can be determined from type curves for concentration, flux, or cumulative flux. The dimensionless form of the type curves provides a means to directly evaluate the importance of mass transport by advection relative to that of mass transport by diffusion and dispersion. Type curves based on an analytical solution to the advection-dispersion equation are plotted in terms of dimensionless time and Peclet number. Flux and cumulative flux type curves provide additional rationale for transport regime determination in addition to the traditional concentration type curves. The extension of type curves to include vapor transport with phase partitioning in the unsaturated zone is a new development. Type curves for negative Peclet numbers also are presented. A negative Peclet number characterizes a problem in which the direction of flow is toward the contamination source, and thereby diffusion and advection can act in opposite directions. Examples are the diffusion of solutes away from the downgradient edge of a pump-and-treat capture zone, the upward diffusion of vapors through the unsaturated zone with recharge, and the diffusion of solutes through a low hydraulic conductivity cutoff wall with an inward advective gradient.

Garges, J.A. [Conestoga-Rovers and Associates, Exton, PA (United States); Baehr, A.L. [Geological Survey, West Trenton, NJ (United States)

1998-11-01

30

Comparative safety analysis of LNG storage tanks  

SciTech Connect

LNG storage tank design and response to selected release scenarios were reviewed. The selection of the scenarios was based on an investigation of potential hazards as cited in the literature. A review of the structure of specific LNG storage facilities is given. Scenarios initially addressed included those that most likely emerge from the tank facility itself: conditions of overfill and overflow as related to liquid LNG content levels; over/underpressurization at respective tank vapor pressure boundaries; subsidence of bearing soil below tank foundations; and crack propagation in tank walls due to possible exposure of structural material to cryogenic temperatures. Additional scenarios addressed include those that result from external events: tornado induced winds and pressure drops; exterior tank missile impact with tornado winds and rotating machinery being the investigated mode of generation; thermal response due to adjacent fire conditions; and tank response due to intense seismic activity. Applicability of each scenario depended heavily on the specific tank configurations and material types selected. (PSB)

Fecht, B.A.; Gates, T.E.; Nelson, K.O.; Marr, G.D.

1982-07-01

31

Rapid removal of selected volatile organic compounds from gaseous mixtures using a new dispersive vapor extraction technique: A feasibility study  

Microsoft Academic Search

A new dispersive vapor extraction (DVE) technique for rapid removal of selected volatile organic compounds (VOCs) from gaseous mixtures was investigated. In this technique, less than 1.0mL of a volatile solvent was vaporized for 8min in a 250-mL flask containing a gaseous mixture. The flask was then cooled under running tap water for 2–3min to induce condensation of the vapor

E. S. Farrell; G. E. Pacey

2010-01-01

32

75 FR 53371 - Liquefied Natural Gas Facilities: Obtaining Approval of Alternative Vapor-Gas Dispersion Models  

Federal Register 2010, 2011, 2012, 2013

...the Technical Committee on Liquefied Natural Gas of the NFPA. Several years ago...LNG Facilities. Subject: Liquefied Natural Gas Facilities: Obtaining Approval of...used with justification provided for the selection of pool diameter(s),...

2010-08-31

33

High efficiency Brayton cycles using LNG  

DOEpatents

A modified, closed-loop Brayton cycle power conversion system that uses liquefied natural gas as the cold heat sink media. When combined with a helium gas cooled nuclear reactor, achievable efficiency can approach 68 76% (as compared to 35% for conventional steam cycle power cooled by air or water). A superheater heat exchanger can be used to exchange heat from a side-stream of hot helium gas split-off from the primary helium coolant loop to post-heat vaporized natural gas exiting from low and high-pressure coolers. The superheater raises the exit temperature of the natural gas to close to room temperature, which makes the gas more attractive to sell on the open market. An additional benefit is significantly reduced costs of a LNG revaporization plant, since the nuclear reactor provides the heat for vaporization instead of burning a portion of the LNG to provide the heat.

Morrow, Charles W. (Albuquerque, NM)

2006-04-18

34

Development of an improved LNG plant failure rate data base. Final report March 1980June 1981  

Microsoft Academic Search

Questionnaires were sent to LNG plant operators requesting data on failures of gas pretreatment systems, vaporizers, compressors, valves, piping, storage tanks, fire and leak detection systems, etc. The responses were combined to broaden the failure rate data base for major LNG plant equipment. The results generally agree with data found in an earlier survey. The results will be useful for

D. W. Johnson; J. R. Welker

1981-01-01

35

Chemical vapor deposited tungsten with dispersed carbides for Space Shuttle check valves  

NASA Technical Reports Server (NTRS)

A chemical vapor deposited tungsten with dispersed carbides was selected as the material for Space Shuttle Orbital Maneuvering and Reaction Control Systems check valve poppets and seats. The selection followed a NASA-sponsored prototype check valve development program utilizing the cutter-seal shell poppet concept. The poppet material is deposited as a coating approximately 0.9 mm thick and fabricated into a shell as a free standing body. The seat material is deposited as a coating 1.1 mm thick on a seat blank, and the cutter seal is machined in the coating. Module tests demonstrated that the material could be ground and lapped to very sharp edges and could cut through typical system contaminants without excessive damage to the sealing surfaces. The material was also determined to be unaffected by exposure to a strongly oxidizing storable propellant.

Williams, G. E.

1980-01-01

36

Thermal and chemical vapor deposition of Si nanowires: Shape control, dispersion, and electrical properties  

SciTech Connect

We investigate and compare complementary approaches to SiNW production in terms of yield, morphology control, and electrical properties. Vapor-phase techniques are considered, including chemical vapor deposition (with or without the assistance of a plasma) and thermal evaporation. We report Au-catalyzed nucleation of SiNWs at temperatures as low as 300 deg. C using SiH{sub 4} as precursor. We get yields up to several milligrams by metal-free condensation of SiO powders. For all processes, we control the final nanostructure morphology. We then report concentrated and stable dispersions of SiNWs in solvents compatible with semiconducting organic polymers. Finally, we investigate the electrical response of intrinsic SiNWs grown by different methods. All our SiNWs exhibit p-type behavior and comparable performance, though in some cases ambipolar devices are observed. Thus, processing and morphology, rather than the growth technique, are key to achieve optimal samples for applications.

Colli, A.; Fasoli, A.; Beecher, P.; Servati, P.; Pisana, S.; Fu, Y.; Flewitt, A. J.; Milne, W. I.; Robertson, J.; Ducati, C.; De Franceschi, S.; Hofmann, S.; Ferrari, A. C. [Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom); Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 6GF (United Kingdom); Laboratoire de Transport Electronique Quantique et Supraconductivite, CEA-Grenoble, 38054 Grenoble cedex 9 (France); Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom)

2007-08-01

37

Vapor-liquid Coexistence Curves for Methanol and Methane using Dispersion-Corrected Density Functional Theory  

SciTech Connect

First principles Monte Carlo simulations in the Gibbs and isobaric-isothermal ensembles were performed to map the vapor-liquid coexistence curves (VLCC) of methanol and methane described by Kohn-Sham density functional theory using the Becke-Lee-Yang-Parr (BLYP) exchange and correlation functionals with the Grimme correction term for dispersive (D2) interactions. The simulations indicate that the BLYP-D2 description underpredicts the saturated vapor densities and overpredicts the saturated liquid densities and critical and boiling temperatures for both compounds. Although the deviations are quite large, these results present a significant improvement over the BLYP functional without the correction term which misses the experimental results by a larger extent in the opposite direction. With the D2 correction, an increase in the basis set does not lead to significant changes in the VLCC properties. This work was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

McGrath, Matthew J.; Kuo, I-F W.; Ghogomu, Julius N.; Mundy, Christopher J.; Siepmann, Joern I.

2011-10-13

38

Determination of octane numbers and Reid vapor pressure in commercial gasoline using dispersive fiber-optic Raman spectroscopy  

Microsoft Academic Search

Dispersive fiber-optic Raman spectroscopy utilizing CCD detection and near-IR DBR diode laser excitation is used to remotely analyze 205 petroleum fuels of varying composition for pump octane number, motor octane number (MON), research octane number (RON), and Reid vapor pressure (RVP). Partial least squares regression analysis in tandem with several preprocessing techniques was used to model pump octane, MON, RON,

Philip E. Flecher; William T. Welch; Sacharia Albin; John B. Cooper

1997-01-01

39

The influence of the dispersion method on the electrical properties of vapor-grown carbon nanofiber/epoxy composites  

PubMed Central

The influence of the dispersion of vapor-grown carbon nanofibers (VGCNF) on the electrical properties of VGCNF/Epoxy composites has been studied. A homogenous dispersion of the VGCNF does not imply better electrical properties. In fact, it is demonstrated that the most simple of the tested dispersion methods results in higher conductivity, since the presence of well-distributed nanofiber clusters appears to be a key factor for increasing composite conductivity. PACS: 72.80.Tm; 73.63.Fg; 81.05.Qk

2011-01-01

40

LNG annotated bibliography  

SciTech Connect

This document updates the bibliography published in Liquefied Gaseous Fuels Safety and Environmental Control Assessment Program: third status report (PNL-4172) and is a complete listing of literature reviewed and reported under the LNG Technical Surveillance Task. The bibliography is organized alphabetically by author.

Bomelburg, H.J.; Counts, C.A.; Cowan, C.E.; Davis, W.E.; DeSteese, J.G.; Pelto, P.J.

1982-09-01

41

LNG Slurry Formation.  

National Technical Information Service (NTIS)

The process of forming particles of frozen crude oil by spraying oil into LNG was originally conceived by LeFever. Analyses by Coulter have shown that the particles formed for slurry transportation must be as small as possible, on the order of 30 micromet...

D. M. Coulter

1975-01-01

42

An LNG release, transport, and fate model system for marine spills.  

PubMed

LNGMAP, a fully integrated, geographic information based modular system, has been developed to predict the fate and transport of marine spills of LNG. The model is organized as a discrete set of linked algorithms that represent the processes (time dependent release rate, spreading, transport on the water surface, evaporation from the water surface, transport and dispersion in the atmosphere, and, if ignited, burning and associated radiated heat fields) affecting LNG once it is released into the environment. A particle-based approach is employed in which discrete masses of LNG released from the source are modeled as individual masses of LNG or spillets. The model is designed to predict the gas mass balance as a function of time and to display the spatial and temporal evolution of the gas (and radiated energy field). LNGMAP has been validated by comparisons to predictions of models developed by ABS Consulting and Sandia for time dependent point releases from a draining tank, with and without burning. Simulations were in excellent agreement with those performed by ABS Consulting and consistent with Sandia's steady state results. To illustrate the model predictive capability for realistic emergency scenarios, simulations were performed for a tanker entering Block Island Sound. Three hypothetical cases were studied: the first assumes the vessel continues on course after the spill starts, the second that the vessel stops as soon as practical after the release begins (3 min), and the third that the vessel grounds at the closest site practical. The model shows that the areas of the surface pool and the incident thermal radiation field (with burning) are minimized and dispersed vapor cloud area (without burning) maximized if the vessel continues on course. For this case the surface pool area, with burning, is substantially smaller than for the without burning case because of the higher mass loss rate from the surface pool due to burning. Since the vessel speed substantially exceeds the spill spreading rate, both the thermal radiation fields and surface pool trail the vessel. The relative directions and speeds of the wind and vessel movement govern the orientation of the dispersed plume. If the vessel stops, the areas of the surface pool and incident radiation field (with burning) are maximized and the dispersed cloud area (without burning) minimized. The longer the delay in stopping the vessel, the smaller the peak values are for the pool area and the size of the thermal radiation field. Once the vessel stops, the spill pool is adjacent to the vessel and moving down current. The thermal radiation field is oriented similarly. These results may be particularly useful in contingency planning for underway vessels. PMID:17110025

Spaulding, Malcolm L; Swanson, J Craig; Jayko, Kathy; Whittier, Nicole

2007-02-20

43

Vapor spill pipe monitor  

DOEpatents

The invention is a method and apparatus for continually monitoring the composition of liquefied natural gas flowing from a spill pipe during a spill test by continually removing a sample of the LNG by means of a probe, gasifying the LNG in the probe, and sending the vaporized LNG to a remote ir gas detector for analysis. The probe comprises three spaced concentric tubes surrounded by a water jacket which communicates with a flow channel defined between the inner and middle, and middle and outer tubes. The inner tube is connected to a pump for providing suction, and the probe is positioned in the LNG flow below the spill pipe with the tip oriented partly downward so that LNG is continuously drawn into the inner tube through a small orifice. The probe is made of a high thermal conductivity metal. Hot water is flowed through the water jacket and through the flow channel between the three tubes to provide the necessary heat transfer to flash vaporize the LNG passing through the inner channel of the probe. The gasified LNG is transported through a connected hose or tubing extending from the probe to a remote ir sensor which measures the gas composition.

Bianchini, G.M.; McRae, T.G.

1983-06-23

44

71 FR 30134 - Trunkline LNG Company, LLC; Notice of Intent To Prepare an Environmental Assessment for the...  

Federal Register 2010, 2011, 2012, 2013

...Trunkline LNG seeks authority to construct and operate the following: 64 Potassium Formate (KF)-Air heaters (64 forced convection, three-fan air exchangers, 17.9 million Btu per hour (MMBtu/ hr)/Air Heater; Four KF-LNG Vaporizers...

2006-05-25

45

LNG pool fire spectral data and calculation of emissive power.  

PubMed

Spectral description of thermal emission from fires provides a fundamental basis on which the fire thermal radiation hazard assessment models can be developed. Several field experiments were conducted during the 1970s and 1980s to measure the thermal radiation field surrounding LNG fires. Most of these tests involved the measurement of fire thermal radiation to objects outside the fire envelope using either narrow-angle or wide-angle radiometers. Extrapolating the wide-angle radiometer data without understanding the nature of fire emission is prone to errors. Spectral emissions from LNG fires have been recorded in four test series conducted with LNG fires on different substrates and of different diameters. These include the AGA test series of LNG fires on land of diameters 1.8 and 6m, 35 m diameter fire on an insulated concrete dike in the Montoir tests conducted by Gaz de France, a 1976 test with 13 m diameter and the 1980 tests with 10 m diameter LNG fire on water carried out at China Lake, CA. The spectral data from the Montoir test series have not been published in technical journals; only recently has some data from this series have become available. This paper presents the details of the LNG fire spectral data from, primarily, the China Lake test series, their analysis and results. Available data from other test series are also discussed. China Lake data indicate that the thermal radiation emission from 13 m diameter LNG fire is made up of band emissions of about 50% of energy by water vapor (band emission), about 25% by carbon dioxide and the remainder constituting the continuum emission by luminous soot. The emissions from the H2O and CO2 bands are completely absorbed by the intervening atmosphere in less than about 200 m from the fire, even in the relatively dry desert air. The effective soot radiation constitutes only about 23% during the burning period of methane and increases slightly when other higher hydrocarbon species (ethane, propane, etc.) are burning in the LNG fire. The paper discusses the procedure by which the fire spectral data are used to predict the thermal emission from large LNG fires. Unfortunately, no direct measurements of the soot density or smoke characteristics were made in the tests. These parameters have significant effect on the thermal emission from large LNG fires. PMID:16920262

Raj, Phani K

2007-04-11

46

Financing aspects of LNG trade  

Microsoft Academic Search

A discussion of key elements in developing a comprehensive financial plan for an LNG system covers the typical project involving a producing nation and a consuming plus a sea-transport element; two key documents: a contract between producer and consumer, and a sea-transport contract; the long life of an LNG project and the advantage of long-term financing for the life of

A. R. Batkin; R. H. Goodspeed

1977-01-01

47

Modeling the release, spreading, and burning of LNG, LPG, and gasoline on water.  

PubMed

Current interest in the shipment of liquefied natural gas (LNG) has renewed the debate about the safety of shipping large volumes of flammable fuels. The size of a spreading pool following a release of LNG from an LNG tank ship has been the subject of numerous papers and studies dating back to the mid-1970s. Several papers have presented idealized views of how the LNG would be released and spread across a quiescent water surface. There is a considerable amount of publicly available material describing these idealized releases, but little discussion of how other flammable fuels would behave if released from similar sized ships. The purpose of this paper is to determine whether the models currently available from the United States Federal Energy Regulatory Commission (FERC) can be used to simulate the release, spreading, vaporization, and pool fire impacts for materials other than LNG, and if so, identify which material-specific parameters are required. The review of the basic equations and principles in FERC's LNG release, spreading, and burning models did not reveal a critical fault that would prevent their use in evaluating the consequences of other flammable fluid releases. With the correct physical data, the models can be used with the same level of confidence for materials such as LPG and gasoline as they are for LNG. PMID:17112658

Johnson, David W; Cornwell, John B

2007-02-20

48

Simultaneous determination of arsenic, antimony, bismuth and mercury in geological materials by vapor generation-four-channel non-dispersive atomic fluorescence spectrometry  

Microsoft Academic Search

Chemical vapor generation (CVG) coupled with non-dispersive atomic fluorescence spectrometry (NDAFS) has been widely used for determination of vapor-forming elements, but most of such works have been focused on single element analysis, and reports dealing with more than three elements simultaneous determination by CVG-NDAFS are rare. In this work, a sensitive and robust analytical procedure for the simultaneous determination of

Zhongxi Li; Xiaoming Yang; Yuean Guo; Haitao Li; Yuhuan Feng

2008-01-01

49

Recommended research on LNG safety  

SciTech Connect

The US Department of Energy (DOE) is conducting research on the safety and other environmental aspects of liquefied energy gases including liquefied natural gas (LNG). The effort reported here was conducted as part of the planning for further research into the safety aspects of transporting and storing LNG, with primary emphasis on public safety. Although the modern LNG industry has enjoyed excellent success in providing for safe operations, significant questions remain on the part of many, the expressions of which were intensified with the addition of marine-based LNG import terminals. Public safety with regard to large-scale importation of this fuel has received widespread attention in the US Congress, state legislatures, county and city governments, and from various individuals and public groups, with coverage in all the news media, including books published on the subject. The safety concerns have centered around the consequences to the public of a large spill of the cryogenic liquid from an ocean tanker or a larger storage tank, either of which might hold as much as 125,000 m/sup 3/ of LNG.

Carpenter, H.J.; Gilmore, F.R.

1981-03-01

50

PRELIMINARY INVESTIGATION OF UNCOMBUSTED AUTO FUEL VAPOR DISPERSION WITHIN A RESIDENTIAL GARAGE MICROENVIRONMENT  

EPA Science Inventory

Evaporative emissions from vehicles in an attached garage may represent a significant source of indoor pollution and human exposure. ilot field study was undertaken to investigate potential in-house dispersion of evaporative emissions of uncombusted fuels from a vehicle parked in...

51

Enhanced reflection via phase compensation from anomalous dispersion in atomic vapor  

SciTech Connect

The phase compensation mechanism induced by anomalous dispersion in the reflection process of four-wave mixing (or reflection from a grating) in a three-level system is investigated, where the four wave vectors do not match in vacuum. An efficiency of the reflected signal of as high as 43% from a hot atomic cell of Cs is observed. The maximum reflection occurs when the frequency of the probe beam (and consequently the frequency of the reflected signal) is slightly red detuned from the transition frequency, which is attributed to the phase compensation from the steep anomalous dispersion accompanied with a strong probe absorption. The dependences of the efficiency on the angle between the coupling and probe lights, on the intensity of the coupling, field and on atomic density are studied. A theoretical model is presented and it is in good agreement with the experimental results.

Zhang Junxiang; Zhou Haitao [State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006 (China); Wang Dawei [Beijing Computational Science Research Center, Beijing 100084 (China); Zhu Shiyao [State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006 (China); Beijing Computational Science Research Center, Beijing 100084 (China); Department of Physics, Hong Kong Baptist University (Hong Kong)

2011-05-15

52

Cove point LNG receiving terminal  

Microsoft Academic Search

A 1-billion-cfd base load LNG receiving and regasification terminal is being built at Cove Point, Maryland. It will handle 650 MMscfd of the gas initially. This article deals with the design and construction phases of this project, with emphasis on engineering for safety. (DLC)

Levy

1976-01-01

53

Investigation of low-cost LNG vehicle fuel tank concepts. Final report  

SciTech Connect

The objective of this study was to investigate development of a low-cost liquid natural gas (LNG) vehicle fuel storage tank with low fuel boil-off, low tank pressure, and high safety margin. One of the largest contributors to the cost of converting a vehicle to LNG is the cost of the LNG fuel tank. To minimize heat leak from the surroundings into the low-temperature fuel, these tanks are designed as cryogenic dewars with double walls separated by an evacuated insulation space containing multi-layer insulation. The cost of these fuel tanks is driven by this double-walled construction, both in terms of materials and labor. The primary focus of the analysis was to try to devise a fuel tank concept that would allow for the elimination of the double-wall requirement. Results of this study have validated the benefit of vacuum/MLI insulation for LNG fuel tanks and the difficulty in identifying viable alternatives. The thickness of a non-vacuum insulation layer would have to be unreasonably large to achieve an acceptable non-venting hold time. Reasonable hold times could be achieved by using an auxiliary tank to accept boil-off vapor from a non-vacuum insulated primary tank, if the vapor in the auxiliary tank can be stored at high pressure. The primary focus of the analysis was to try to devise a fuel tank concept that allowed for the elimination of the double-wall requirement. Thermodynamic relations were developed for analyzing the fuel tank transient response to heat transfer, venting of vapor, and out-flow of either vapor or liquid. One of the major costs associated with conversion of a vehicle to LNG fuel is the cost of the LNG fuel tank. The cost of these tanks is driven by the cryogenic nature of the fuel and by the fundamental design requirements of long non-venting hold times and low storage pressure.

O`Brien, J.E.; Siahpush, A. [Lockheed Martin Idaho Technologies Co., Idaho Falls, ID (United States). Idaho National Engineering and Environmental Lab.

1998-02-01

54

71 FR 67554 - Trunkline LNG Company, LLC ; Notice of Availability of the Environmental Assessment for the...  

Federal Register 2010, 2011, 2012, 2013

...unit (Btu) control. The facilities would include the following: 64 Potassium Formate (KF)-Air heaters (64 forced convection, three-fan air exchangers, 17.9 million Btu per hour (MMBtu/ hr)/Air Heater; Four KF-LNG Vaporizers...

2006-11-22

55

Effect of Mo Dispersion Size and Water Vapor on Oxidation of Two-Phase Directionally Solidified NiAl-9Mo In-Situ Composites  

SciTech Connect

Oxidation of two-phase NiAl-9Mo eutectics with 3 different growth rates/2nd phase Mo dispersion sizes were investigated at 900 C in air and air with 10% water vapor. Good oxidation resistance via alumina formation was observed in dry air, with Mo volatilization loss minimized by fine submicron Mo dispersions. However, extensive Mo volatilization and in-place internal oxidation of prior Mo phase regions was observed in wet air oxidation. Ramifications of this phenomenon for the development of multi-phase high-temperature alloys are discussed

Brady, Michael P [ORNL] [ORNL; Bei, Hongbin [ORNL] [ORNL; Meisner, Roberta Ann [ORNL] [ORNL; Lance, Michael J [ORNL] [ORNL; Tortorelli, Peter F [ORNL] [ORNL

2014-01-01

56

Analysing the risk of LNG carrier operations  

Microsoft Academic Search

This paper presents a generic, high-level risk assessment of the global operation of ocean-going liquefied natural gas (LNG) carriers. The analysis collects and combines information from several sources such as an initial hazid, a thorough review of historic LNG accidents, review of previous studies, published damage statistics and expert judgement, and develops modular risk models for critical accident scenarios. In

Erik Vanem; Pedro Antão; Ivan Østvik; Francisco Del Castillo de Comas

2008-01-01

57

Cove Point LNG receiving terminal control systems  

Microsoft Academic Search

The control systems installed to operate the Cove Point LNG receiving terminal have performed exceptionally well, reports Columbia LNG Corp. All major equipment at the terminal is operated locally from manned monitoring stations that are linked via telemetry to the computer in the terminal's main control room. An independent emergency system, activated by designated pushbuttons located throughout the plants, automatically

Kazinoff

1979-01-01

58

Vaporizing Vapor  

NSDL National Science Digital Library

In this demonstration, relative humidity is modeled using a sponge and a pan of water, and the concept of saturation is depicted. Students answer questions examining the relationship between temperature and the capacity of air to hold water vapor. The resource is part of the teacher's guide accompanying the video, NASA Sci Files: The Case of the Phenomenal Weather. Lesson objectives supported by the video, additional resources, teaching tips and an answer sheet are included in the teacher's guide.

59

Cove Point LNG terminal: its first year of operation  

Microsoft Academic Search

As of mid-Nov. 1978, the Cove Point LNG terminal, jointly owned by Columbia LNG Corp. and Consolidated System LNG Co., has received 13 shiploads of LNG from Algeria, delivering 30 billion cu ft of gas to regional distribution systems without significant operating or safety problems. Although the terminal has not yet reached its design throughput, performance has been very satisfactory.

Levy

1979-01-01

60

Feasibility of methods and systems for reducng LNG tanker fire hazards  

SciTech Connect

In this program concepts for reducing fire hazards that may result from LNG tanker collisions are identified and their technical feasibility evaluated. Concepts considered include modifications to the shipborne LNG containers so that in the event of a container rupture less of the contents would spill and/or the contents would spill at a reduced rate. Changes in the cargo itself, including making the LNG into a gel, solidifying it, converting it to methanol, and adding flame suppressants are also evaluated. The relative effectiveness and the costs of implementing these methods in terms of increased cost of gas at the receiving terminal, are explained. The vulnerability of an LNG tanker and its crew to the thermal effects of a large pool fire caused by a collision spill is estimated and methods of protecting the crew are considered. It is shown that the protection of ship and crew so that further deterioration of a damaged ship might be ameliorated, would require the design and installation of extraordinary insulation systems and life support assistance for the crew. Methods of salvaging or disposing of cargo from a damaged and disabled ship are evaluated, and it is concluded that if the cargo cannot be transferred to another (empty) LNG tanker because of lack of availability, then the burning of the cargo at a location somewhat distant from the disabled tanker appears to be a promising approach. Finally, the likelihood of the vapors from a spill being ignited due to the frictional impact of the colliding ships was examined. It is found that the heating of metal sufficient to ignite flammable vapors would occur during a collision, but it is questionable whether flammable vapor and air will, in fact, come in contact with the hot metal surfaces.

Not Available

1980-08-01

61

Potential for world trade in LNG  

SciTech Connect

Deliveries of LNG in 1978 in international trade amounted to about 24.77 billion cu m; of the actual deliveries, 9% were received by the U.S., 30% by West European countries, and 61% by Japan. For Spain, these deliveries represented 100% of its natural gas supply; for the U.S., they represented only 2% of natural gas demand. By the mid-1980's, the international LNG growth rate will slow to approx. 16%/yr, although projects totaling 130 million cu m/day may be completed. During the late 1980's, another 94.1 million cu m/day of LNG projects could be implemented. The over-all growth rate for the decade would then be approx. 11%/yr in LNG volumes. After 1990, several LNG export projects could be put into operation, possibly in the Middle East, West Africa, and the U.S.S.R. In 1980-2000, energy demand may increase by 2%/yr. Oil should retain its 65-70% of the primary energy supply; whether natural gas can increase its relative share depends on economic and political factors. Pipeline transport of gas costs twice as much as crude oil, and sea transport of LNG costs four to five times as much as crude oil. Wider use of the refrigeration available at LNG import terminals could affect project economics favorably. Tables.

Anderson, P.J.

1980-01-01

62

On the application of computational fluid dynamics codes for liquefied natural gas dispersion  

Microsoft Academic Search

Computational fluid dynamics (CFD) codes are increasingly being used in the liquefied natural gas (LNG) industry to predict natural gas dispersion distances. This paper addresses several issues regarding the use of CFD for LNG dispersion such as specification of the domain, grid, boundary and initial conditions. A description of the k–? model is presented, along with modifications required for atmospheric

Anay Luketa-Hanlin; Ronald P. Koopman; Donald L. Ermak

2007-01-01

63

Damage-detection system for LNG carriers  

NASA Technical Reports Server (NTRS)

System utilizes array of acoustical transducers to detect cracks and leaks in liquefied natural gas (LNG) containers onboard ships. In addition to detecting leaks, device indicates location and leak rate.

Mastandrea, J. R.; Scherb, M. V.

1978-01-01

64

Imported LNG to serve east coast utilities  

Microsoft Academic Search

Through the El Paso Natural Gas Co. project, Consolidated Natural Gas Co. and Columbia Gas System, Inc., expect to import Algerian LNG equivalent to 650 million ft³\\/day of natural gas by 1977, with initial deliveries to start in late 1976. The project will eventually cost $2 billion and involve LNG imports equivalent to 1 billion ft³\\/day of gas. Arriving from

1974-01-01

65

Keys to modeling LNG spills on water.  

PubMed

Although no LNG ship has experienced a loss of containment in over 40 years of shipping, it is important for risk management planning to understand the predicted consequences of a spill. A key parameter in assessing the impact of an LNG spill is the pool size. LNG spills onto water generally result in larger pools than land spills because they are unconfined. Modeling of LNG spills onto water is much more difficult than for land spills because the phenomena are more complex and the experimental basis is more limited. The most prevalent practice in predicting pool sizes is to treat the release as instantaneous or constant-rate, and to calculate the pool size using an empirical evaporation or burn rate. The evaporation or burn rate is particularly difficult to estimate for LNG spills on water, because the available data are so limited, scattered, and difficult to extrapolate to the large releases of interest. A more effective modeling of possible spills of LNG onto water calculates, rather than estimating, the evaporation or burn rate. The keys to this approach are to: * Use rigorous multicomponent physical properties. * Use a time-varying analysis of spill and evaporation. * Use a material and energy balance approach. * Estimate the heat transfer from water to LNG in a way that reflects the turbulence. These keys are explained and demonstrated by predictions of a model that incorporates these features. The major challenges are describing the effects of the LNG-water turbulence and the heat transfer from the pool fire to the underlying LNG pool. The model includes a fundamentally based framework for these terms, and the current formulation is based on some of the largest tests to-date. The heat transfer coefficient between the water and LNG is obtained by applying a "turbulence factor" to the value from correlations for quiescent film and transition boiling. The turbulence factor is based on two of the largest unignited tests on water to-date. The heat transfer from the fire to the pool is based on the burning rate for the largest pool fire test on land to-date. PMID:17113709

Hissong, D W

2007-02-20

66

LNG fires: a review of experimental results, models and hazard prediction challenges.  

PubMed

A number of experimental investigations of LNG fires (of sizes 35 m diameter and smaller) were undertaken, world wide, during the 1970s and 1980s to study their physical and radiative characteristics. This paper reviews the published data from several of these tests including from the largest test to date, the 35 m, Montoir tests. Also reviewed in this paper is the state of the art in modeling LNG pool and vapor fires, including thermal radiation hazard modeling. The review is limited to considering the integral and semi-empirical models (solid flame and point source); CFD models are not reviewed. Several aspects of modeling LNG fires are reviewed including, the physical characteristics, such as the (visible) fire size and shape, tilt and drag in windy conditions, smoke production, radiant thermal output, etc., and the consideration of experimental data in the models. Comparisons of model results with experimental data are indicated and current deficiencies in modeling are discussed. The requirements in the US and European regulations related to LNG fire hazard assessment are reviewed, in brief, in the light of model inaccuracies, criteria for hazards to people and structures, and the effects of mitigating circumstances. The paper identifies: (i) critical parameters for which there exist no data, (ii) uncertainties and unknowns in modeling and (iii) deficiencies and gaps in current regulatory recipes for predicting hazards. PMID:17156916

Raj, Phani K

2007-02-20

67

Characterization of the Near-Field Transport and Dispersion of Vapors Released from the Headspaces of Hanford Site Underground Storage Tanks  

SciTech Connect

A parametric air dispersion analysis has been conducted to define the range of tank vapor concentrations from the Hanford Site underground tanks that can potentially occur in the worker breathing zones from active and passive releases from the waste tanks. The potential influences of tank farm specific release characteristics, ambient meteorological conditions, local farm surface roughness, and topographical influences are considered. The parametric approach allows consideration of the full range venting configurations and potential vapor concentration over the range of meteorological conditions at the Hanford Site. The results indicate that occasional short duration exposures of up to several seconds to relatively undiluted headspace air can be expected in the immediate vicinity of the tank vents. Average concentrations which represent diffusion, as well as spatial averaging, fall off rapidly with distance for the passive vents and to a lesser extent for the forced-air stacks. The addition of the influence of the surface roughness elements on the tank farms will result in a faster decrease of concentrations with downwind distance.

Droppo, James G.

2004-07-30

68

Re-Examining the Properties of the Aqueous Vapor-Liquid Interface Using Dispersion Corrected Density Functional Theory  

SciTech Connect

First-principles molecular dynamics simulations, in which the forces are computed from electronic structure calculations, have great potential to provide unique insight into structure, dynamics, electronic properties, and chemistry at aqueous interfaces that is not available from empirical force fields. The majority of current first-principles simulations are driven by forces derived from density functional theory with generalized gradient approximations to the exchange-correlation energy, which do not capture dispersion interactions. We have carried out first-principles molecular dynamics simulations of air-water interfaces employing a particular generalized gradient approximation to the exchange-correlation functional (BLYP), with and without empirical dispersion corrections. We assess the utility of the dispersion corrections by comparison of a variety of structural, dynamic, and thermodynamic properties of bulk and interfacial water with experimental data, as well as other first-principles and force field-based simulations. This work was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

Baer, Marcel D.; Mundy, Christopher J.; McGrath, Matthew J.; Kuo, I-F W.; Siepmann, Joern I.; Tobias, Douglas J.

2011-09-28

69

Numerical Research on LNG Tank Leakage Effect on Environment for LNG Bus  

Microsoft Academic Search

Study and analysis the fuel leakage security of current LNG alternative fuel bus. Do the simulation on surrounding concentration and temperature of LNG bus fuel tank leakage by Computational Fluid Dynamics (CFD). By analyzing the influence of three different bus velocities, 0km\\/h, 30km\\/h and 80km\\/h, we have the conclusion from the simulation that when the bus gets faster, the influence

Lei Zhang; Ying Gao; Da-wen Liu; Peng Liu

2011-01-01

70

Electricity Generation by Utilization of LNG Cold.  

National Technical Information Service (NTIS)

LNG has, after it has been raised to the usual pipeline pressures, a high useful energy (= technical work potential). With modern large terminals the energy potentials are of the order of 100 MW. In the light of the increase in the cost of energy the ques...

M. Streich A. W. D. Pocrnja

1977-01-01

71

77 FR 73627 - 2012 LNG Export Study  

Federal Register 2010, 2011, 2012, 2013

...world demand for natural gas increases rapidly, and if LNG supplies from other regions are limited. If the promise of shale gas is not fulfilled and costs of producing gas in the U.S. rise substantially, or if there are ample supplies of...

2012-12-11

72

Accident at the Cove Point LNG facility  

Microsoft Academic Search

On October 6, 1979, an explosion occurred at the Cove Point, Md, liquefied natural gas receiving terminal when leaking LNG was ignited by an electrical arc. The explosion destroyed an electrical substation building containing switchgear and motor controllers. This paper briefly describes the accident itself, the source of the gas leakage and cause of the explosion. Details of the seal

Van Meerbeke

1982-01-01

73

Grain structure and growth of dispersed phase BN-AlN coatings grown via chemical vapor deposition  

SciTech Connect

This paper discusses the variation in microstructures encountered during the separate depositions of boron nitride (BN) and aluminium nitride (AlN) as well as during the codeposition of BN-AlN dispersed phase ceramic coatings. This combination was chosen in order to take advantage of the self lubricating properties of hexagonal BN along with the hard, erosion resistance of AlN. Films were characterized using scanning and transmission electron microscopy (SEM and TEM), x-ray photoelectron spectroscopy (XPS), and x-ray diffraction (XRD). A range of coating microstructures are possible depending on the conditions of deposition. The best films produced, in terms of hardness, density, and tenacity, were a fine mixture of turbostratic BN and preferentially oriented A1N whiskers aligned with the whisker axis perpendicular to the substrate surface as seen by both electron microscopy and x-ray diffraction. 4 refs., 9 figs., 1 tab.

Freeman, G.B.; Lackey, W.J.; Hanigofsky, J.A. (Georgia Inst. of Tech., Atlanta, GA (USA). Georgia Technology Research Inst.); Lee, Woo Y. (United Technologies Research Center, East Hartford, CT (USA)); More, K.L. (Oak Ridge National Lab., TN (USA))

1990-01-01

74

U.S. LNG Imports - The Next Wave  

EIA Publications

U.S. LNG imports - The Next Wave, is now available as a special supplement to the January 2007 issue of the Short-Term Energy Outlook (STEO). Although liquefied natural gas (LNG) imports still account for less than 3% of total U.S. natural gas supplies, the global market is growing and the Energy Information Administration (EIA) foresees another wave of U.S. LNG import growth over the next two years. The supplement focuses on recent trends in global and U.S. LNG trade, and presents factors expected to influence LNG imports through 2008. EIA expects year-over-year increases in LNG imports of 34.5% and 38.5% in 2007 and 2008, respectively.

Information Center

2007-01-11

75

Potential for long-term LNG supply. Final report  

Microsoft Academic Search

Limited foreign liquefaction and U.S. LNG terminal capacity exists before 1993, after which time re-opening of the Cove Point and, later, Elba Island terminals, together with the refurbishment of inefficient Algerian liquefaction plant, permits a major expansion in U.S.-North African LNG trade. Towards 2000 expansion of all four U.S. LNG receiving terminals is technically possible, providing appropriate market, regulatory and

T. I. Moncrieff; D. P. Goldman; E. F. Jeffries; J. L. Sherff; J. C. Wood-Collins

1991-01-01

76

Submarine LNG tanker concept for the Arctic  

Microsoft Academic Search

If LNG tankers could travel underwater, they could transport natural gas from Arctic regions year-round. General Dynamics has designed just such a tanker - a 140,000-m³ submarine with a methane-fired steam-propulsion system that uses recirculated exhaust gas injected with oxygen to sustain combustion. (Nuclear power would be cheaper but might not be practical if new regulations are imposed.) Developed from

P. T. Veliotis; S. Reitz

1981-01-01

77

Fire performance of LNG carriers insulated with polystyrene foam  

Microsoft Academic Search

Analysis of the response of a liquid-full Moss Sphere LNG tank insulated with polystyrene foam to an engulfing LNG fire indicates that current regulatory requirements for pressure relief capacity sufficient to prevent tank rupture are inadequate. The inadequacy of the current requirements stems primarily from two factors. Firstly, the area of the Moss Sphere protruding above what would be the

Jerry Havens; James Venart

2008-01-01

78

Performance of cryogenic thermoelectric generators in LNG cold energy utilization  

Microsoft Academic Search

The cold energy of liquefied natural gas (LNG) is generally wasted when the LNG is extracted for utilization. This paper proposes cryogenic thermoelectric generators to recover this cold energy. The theoretical performance of the generator has been analyzed. An analytical method and numerical method of calculation of the optimum parameters of the generator have been demonstrated.

Wei Sun; Peng Hu; Zeshao Chen; Lei Jia

2005-01-01

79

Do we or don't we want LNG  

Microsoft Academic Search

The promise and performance of LNG was discussed previously when the Cove Point, Maryland terminal was under construction. Now that it is operational (the first LNG ship arrived and unloaded the equivalent of 2.5 billion cubic feet of natural gas March 13, 1978), the price and safety debate continues. These issues are discussed in detail. Some comments from industrialists are

Crull

2009-01-01

80

Imported LNG (liquid natural gas) as an alternative fuel  

Microsoft Academic Search

Imports of liquefied natural gas (LNG) first arrived in the United States in 1972 at the rate of one billion cubic feet (Bcf) per year. By 1979, they had reached 252 Bcf\\/year. However, as US as demand declined and domestic deliverability grew, inflexible LNG prices led to the complete collapse of trade during the 1980s. In 1987, all four US

1990-01-01

81

Submarine LNG tanker concept for the Arctic  

SciTech Connect

If LNG tankers could travel underwater, they could transport natural gas from Arctic regions year-round. General Dynamics has designed just such a tanker - a 140,000-m/sup 3/ submarine with a methane-fired steam-propulsion system that uses recirculated exhaust gas injected with oxygen to sustain combustion. (Nuclear power would be cheaper but might not be practical if new regulations are imposed.) Developed from parametric variations in cargo capacity, hull material, and ballasting, the design identifies such ship characteristics as length, beam, depth, cargo-system arrangement, speed, and ship control. An economic analysis indicates the concept's competitiveness with both pipelines and icebreaking tankers.

Veliotis, P.T.; Reitz, S.

1981-01-01

82

First US LNG base load trade from Algeria, the Cove Point Operation  

Microsoft Academic Search

The Algeria 1 LNG project, by far the largest LNG-import project in the world, has proved a beneficial source of energy for the Atlantic Coast states, owing to extensive crew training, good terminal-operating procedures, and US Coast Guard monitoring procedures. Participating in the project with El Paso Marine Co. are Columbia LNG Corp. and Consolidated System LNG Co., which receive

J. W. Kime; J. W. Boylston; J. Van Dyke

1979-01-01

83

Electric propulsion for LNG Carriers Full-size LNG carriers with dual fuel diesel engines and electric propulsion are now under construction in France. The authors present the benefits and design features of electric propulsion systems in LNG shipping applications  

Microsoft Academic Search

he current world usage of LNG is about 110 million tons per year and current analysis indicates this grow- ing in the next 10 years by 70 to 100 million tons. This may lead to demand for more than 80 new LNG carriers by 2010, in addi- tion to those already under construction. Traditionally LNG carriers have been pro- pelled

Jan Fredrik; Rune Lysebo

84

Lng weathering effects: Theoretical and empirical. Topical report, March-August 1992. [LNG (Liquified Natural Gas)  

SciTech Connect

The report details the composition change of LNG as it weathers in a vehicle size tank. The composition methane number and stoichiometric air-fuel ratios each change with composition. The results show that the factor controlling weathering is the tank heat leak rate. Weathering occurs at a constant rate when plotted against tank volume, that is composition change is primarily a function of tank volume and the percentage of initial fill boiled off. Heat leak defines the rate at which weathering occurs.

Acker, G.H.; Moulton, S.D.

1992-12-01

85

Vaporization of Droplets in Premixing Chambers.  

National Technical Information Service (NTIS)

Detailed measurements were made of the structures of turbulent fuel sprays vaporizing in heated airstreams. The measurements show the size dependent vaporization and dispersion of the droplets and the important influence of the large eddies in the turbule...

A. J. Yule N. A. Chigier

1980-01-01

86

Dynamic Simulation of the Liquefaction Section in Baseload LNG Plants.  

National Technical Information Service (NTIS)

This thesis demonstrates modeling and simulation of a cryogenic heat exchangers in a baseload Liquefied Natural Gas (LNG) plant. The work comprises two main areas. The first concerns the development and description of the transient liquefaction models. Th...

E. Melaaen

1994-01-01

87

Dynamic simulation of the liquefaction section in baseload LNG plants.  

National Technical Information Service (NTIS)

The thesis demonstrates modelling and simulation of a cryogenic heat exchanger in a baseload LNG plant within two main areas. The first one concerns the development and description of the transient liquefaction models. The second one looks at the verifica...

E. Melaaen

1994-01-01

88

Numerical Simulation and Optimazation of Small Scale LNG Plant  

NASA Astrophysics Data System (ADS)

The LNG20 is a small-scale natural gas liquefier. Its capacity is 20 cube meters LNG per day. This liquefier could be used for the pipeline gas, coalbed gas, oil field gas liquefaction and peakshaving plant for town gas gate station and natural gas power plant. Two processing cycles are applied to LNG20, nitrogen expander cycle and mixed refrigerant cycle. In this report, two feed gases are the target sources; one is the pipeline gas in ``West-to-east pipeline gas'' in a gate station in Zhejiang province and coalbed gas in Northeast China. The numerical simulation and optimization for the LNG20 were carried out to obtain the design parameters.

Li, H. Y.; Jia, L. X.; Fan, Q. H.; Yin, Q. S.

2006-04-01

89

The Phoenix series large scale LNG pool fire experiments.  

SciTech Connect

The increasing demand for natural gas could increase the number and frequency of Liquefied Natural Gas (LNG) tanker deliveries to ports across the United States. Because of the increasing number of shipments and the number of possible new facilities, concerns about the potential safety of the public and property from an accidental, and even more importantly intentional spills, have increased. While improvements have been made over the past decade in assessing hazards from LNG spills, the existing experimental data is much smaller in size and scale than many postulated large accidental and intentional spills. Since the physics and hazards from a fire change with fire size, there are concerns about the adequacy of current hazard prediction techniques for large LNG spills and fires. To address these concerns, Congress funded the Department of Energy (DOE) in 2008 to conduct a series of laboratory and large-scale LNG pool fire experiments at Sandia National Laboratories (Sandia) in Albuquerque, New Mexico. This report presents the test data and results of both sets of fire experiments. A series of five reduced-scale (gas burner) tests (yielding 27 sets of data) were conducted in 2007 and 2008 at Sandia's Thermal Test Complex (TTC) to assess flame height to fire diameter ratios as a function of nondimensional heat release rates for extrapolation to large-scale LNG fires. The large-scale LNG pool fire experiments were conducted in a 120 m diameter pond specially designed and constructed in Sandia's Area III large-scale test complex. Two fire tests of LNG spills of 21 and 81 m in diameter were conducted in 2009 to improve the understanding of flame height, smoke production, and burn rate and therefore the physics and hazards of large LNG spills and fires.

Simpson, Richard B.; Jensen, Richard Pearson; Demosthenous, Byron; Luketa, Anay Josephine; Ricks, Allen Joseph; Hightower, Marion Michael; Blanchat, Thomas K.; Helmick, Paul H.; Tieszen, Sheldon Robert; Deola, Regina Anne; Mercier, Jeffrey Alan; Suo-Anttila, Jill Marie; Miller, Timothy J.

2010-12-01

90

Liquefied Noble Gas (LNG) detectors for detection of nuclear materials  

Microsoft Academic Search

Liquefied-noble-gas (LNG) detectors offer, in principle, very good energy resolution for both neutrons and gamma rays, fast response time (hence high-count-rate capabilities), excellent discrimination between neutrons and gamma rays, and scalability to large volumes. They do, however, need cryogenics. LNG detectors in sizes of interest for fissionable material detection in cargo are reaching a certain level of maturity because of

J A Nikkel; T Gozani; C Brown; J Kwong; D N McKinsey; Y Shin; S Kane; C Gary; M Firestone

2012-01-01

91

Startup of El Paso's Algeria I LNG project  

Microsoft Academic Search

The project involves the importation of the LNG equivalent of 1 billion cu ft\\/day of Algerian natural gas from Sonatrach to the U.S. east coast: 650 million cu ft\\/day to Cove Point, Md., including 350 million cu ft\\/day to Consolidated System LNG Co., and another 350 million cu ft\\/day will be delivered to Southern Energy Corp.'s Elba Island (Ga.) terminal.

Schmitt

1978-01-01

92

LNG terminal will ease gas shortage. [Cove Point, Maryland  

Microsoft Academic Search

Columbia LNG Corp., a subsidiary of the Columbia Gas System, Wilmington, Del., is nearing completion of a 1-billion-cfd base-load LNG receiving and regasification terminal at Cove Point, Md. Initially, the terminal will handle 650 MMscfd of gas with Columbia receiving 300 MMscfd and the remainder (350 MMscfd) going to Consolidated Natural Gas System, co-owner of the terminal. Importation of the

Levy

1976-01-01

93

LNG Safety Research: FEM3A Model Development  

SciTech Connect

The initial scope of work for this project included: (1) Improving the FEM3A advanced turbulence closure module, (2) Adaptation of FEM3A for more general applications, and (3) Verification of dispersion over rough surfaces, with and without obstacle using the advanced turbulence closure module. These work elements were to be performed by Chemical Hazards Research Center (CHRC), Department of Chemical Engineering, University of Arkansas as a subcontractor to Gas Technology Institute (GTI). The tasks for GTI included establishment of the scientific support base for standardization of the FEM3A model, project management, technology transfer, and project administration. Later in the course of the project, the scope of work was modified by the National Energy Technology Laboratories (NETL) to remove the emphasis on FEM3A model and instead, develop data in support of NETL's FLUENT modeling. With this change, GTI was also instructed to cease activities relative to FEM3A model. GTI's technical activities through this project included the initial verification of FEM3A model, provision of technical inputs to CHRC researchers regarding the structure of the final product, and participation in technical discussion sessions with CHRC and NETL technical staff. GTI also began the development of a Windows-based front end for the model but the work was stopped due to the change in scope of work. In the meantime, GTI organized a workshop on LNG safety in Houston, Texas. The workshop was very successful and 75 people from various industries participated. All technical objectives were met satisfactorily by Dr. Jerry Havens and Dr. Tom Spicer of CHRC and results are presented in a stand-alone report included as Appendix A to this report.

Iraj A. Salehi; Jerry Havens; Tom Spicer

2006-09-30

94

LNG cascading damage study. Volume I, fracture testing report.  

SciTech Connect

As part of the liquefied natural gas (LNG) Cascading Damage Study, a series of structural tests were conducted to investigate the thermal induced fracture of steel plate structures. The thermal stresses were achieved by applying liquid nitrogen (LN{sub 2}) onto sections of each steel plate. In addition to inducing large thermal stresses, the lowering of the steel temperature simultaneously reduced the fracture toughness. Liquid nitrogen was used as a surrogate for LNG due to safety concerns and since the temperature of LN{sub 2} is similar (-190 C) to LNG (-161 C). The use of LN{sub 2} ensured that the tests could achieve cryogenic temperatures in the range an actual vessel would encounter during a LNG spill. There were four phases to this test series. Phase I was the initial exploratory stage, which was used to develop the testing process. In the Phase II series of tests, larger plates were used and tested until fracture. The plate sizes ranged from 4 ft square pieces to 6 ft square sections with thicknesses from 1/4 inches to 3/4 inches. This phase investigated the cooling rates on larger plates and the effect of different notch geometries (stress concentrations used to initiate brittle fracture). Phase II was divided into two sections, Phase II-A and Phase II-B. Phase II-A used standard A36 steel, while Phase II-B used marine grade steels. In Phase III, the test structures were significantly larger, in the range of 12 ft by 12 ft by 3 ft high. These structures were designed with more complex geometries to include features similar to those on LNG vessels. The final test phase, Phase IV, investigated differences in the heat transfer (cooling rates) between LNG and LN{sub 2}. All of the tests conducted in this study are used in subsequent parts of the LNG Cascading Damage Study, specifically the computational analyses.

Petti, Jason P.; Kalan, Robert J.

2011-12-01

95

Impacts of offshore liquid natural gas (LNG) terminals on local fish populations in Mass Bay  

Microsoft Academic Search

This study examines the effect of offshore liquid natural gas (LNG) terminals on local fish populations. Two LNG sites and two control sites in Massachusetts Bay were surveyed using hydroacoustics during June 2009. Each LNG site contains an identical subsurface structure, and is at the center of an 800 m radius zone where fishing is prohibited. Control sites do not

Catherine Caruso; J. Idjadi; K. Lagueux; J. Mandelman

2010-01-01

96

Analysis of LNG peakshaving-facility release-prevention systems  

SciTech Connect

The purpose of this study is to provide an analysis of release prevention systems for a reference LNG peakshaving facility. An overview assessment of the reference peakshaving facility, which preceeded this effort, identified 14 release scenarios which are typical of the potential hazards involved in the operation of LNG peakshaving facilities. These scenarios formed the basis for this more detailed study. Failure modes and effects analysis and fault tree analysis were used to estimate the expected frequency of each release scenario for the reference peakshaving facility. In addition, the effectiveness of release prevention, release detection, and release control systems were evaluated.

Pelto, P.J.; Baker, E.G.; Powers, T.B.; Schreiber, A.M.; Hobbs, J.M.; Daling, P.M.

1982-05-01

97

Hawaii energy strategy project 2: Fossil energy review. Task 3 -- Greenfield options: Prospects for LNG use  

SciTech Connect

This paper begins with an overview of the Asia-Pacific LNG market, its major players, and the likely availability of LNG supplies in the region. The discussion then examines the possibilities for the economic supply of LNG to Hawaii, the potential Hawaiian market, and the viability of an LNG project on Oahu. This survey is far from a complete technical assessment or an actual engineering/feasibility study. The economics alone cannot justify LNG`s introduction. The debate may continue as to whether fuel diversification and environmental reasons can outweigh the higher costs. Several points are made. LNG is not a spot commodity. Switching to LNG in Hawaii would require a massive, long-term commitment and substantial investments. LNG supplies are growing very tight in the Asia-Pacific region. Some of the environmental benefits of LNG are not entirely relevant in Hawaii because Hawaii`s air quality is generally excellent. Any air quality benefits may be more than counterbalanced by the environmental hazards connected with large-scale coastal zone construction, and by the safety hazards of LNG carriers, pipelines, etc. Lastly, LNG is not suitable for all energy uses, and is likely to be entirely unsuitable for neighbor island energy needs.

Breazeale, K. [ed.; Fesharaki, F.; Fridley, D.; Pezeshki, S.; Wu, K.

1993-12-01

98

Fire performance of LNG carriers insulated with polystyrene foam.  

PubMed

Analysis of the response of a liquid-full Moss Sphere LNG tank insulated with polystyrene foam to an engulfing LNG fire indicates that current regulatory requirements for pressure relief capacity sufficient to prevent tank rupture are inadequate. The inadequacy of the current requirements stems primarily from two factors. Firstly, the area of the Moss Sphere protruding above what would be the nominal deck on a conventional carrier, which is protected only by a steel weather cover from exposure to heat from a tank-engulfing fire, is being underestimated. Secondly, aluminum foil-covered polystyrene foam insulation applied to the exterior of the LNG tank is protected above the deck only by the steel weather cover under which the insulation could begin to melt in as little as 1-3 min, and could completely liquefy in as few as 10 min. U.S. and International Regulations require that the insulations on the above-deck portion of tanks have approved fire proofing and stability under fire exposure. Polystyrene foam, as currently installed on LNG carriers, does not appear to meet these criteria. As a result of these findings, but giving no consideration to the significant potential for further damage if the polystyrene should burn, the boil-off rate is predicted to be an order-of-magnitude higher than provided for by current PRV sizing requirements. PMID:18372107

Havens, Jerry; Venart, James

2008-10-30

99

LNG insurance bill seen hiking cost, cutting supply  

Microsoft Academic Search

Opponents to a House bill requiring importers of liquefied natural gas (LNG) to guarantee up to $100 million liability for an accident claim it will raise costs and restrict supplies to users if enacted. Sponsored by the House subcommittee on commerce energy and power, the bill's chances are unknown. It is designed to coordinate licensing procedures, but its safety rules

OBrien

1978-01-01

100

First big LNG unit seen boosting East's gas supply  

Microsoft Academic Search

A liquefied natural gas (LNG) importation project, scheduled to begin operating at Cove Pt., Maryland in mid-March, will provide seven eastern states with one million cubic feet of gas per day for 25 years. Seven southern states will be served by a second terminal at Savannah, Georgia. Three pipelines will buy the Algerian gas. The project has enabled gas utilities

Ruth

1978-01-01

101

Peak shaving with LNG from Cove Point Terminal  

Microsoft Academic Search

The differing calorific values of US gas and regasified Algerian LNG posed thermodynamic problems in BG and E's gas-liquefaction peakshaving plant. The fluctuating US\\/imported gas mix entering the liquefiers required the pretreatment system to operate at all times. Removal of the excess hydrocarbons carried in the imported gas resulted in refrigeration losses amounting to 20% of the plant capacity. To

1981-01-01

102

LNG Plant Optimization Tool CryoPro: A Joint Venture.  

National Technical Information Service (NTIS)

A base-load LNG plant is planned for the 'Snohvit' field in northern Norway. A design optimization tool, CryoPro, was developed by Statoil R&D and the Division of Refrigeration Engineering, NTH-SINTEF, to be used in concept evaluations. The conditions in ...

G. Owren E. Brendeng R. S. Heiersted A. Fredheim

1992-01-01

103

Soot-Free Combustion Of Methane And LNG  

NASA Technical Reports Server (NTRS)

Neither methane nor liquefied natural gas (LNG) produces soot when burned in turbine simulator with liquid oxygen under conditions like those in gas-generator section of rocket engine. Experiments conducted to determine if these fuels behave similarly to other hydrocarbon fuels, which give off soot coating turbomachinery and reducing performance.

Bossard, John

1992-01-01

104

Analysis of LNG import terminal release prevention systems  

SciTech Connect

The release prevention systems of liquefied natural gas (LNG) import terminal were analyzed. A series of potential release scenarios were analyzed to determine the frequency of the release events, the probability these releases are not stopped or isolated by emergency shutdown systems, the estimated release quantities, and the critical components of the system. The two plant areas identified as being most significant with respect to safety are the unloading system and the storage system. Rupture of the main transfer line and gross failure of the storage tanks are the two release scenarios of primary safety interest. Reducing the rate of failure by improved design, better maintenance and testing, or adding redundancy of the critical system components for these plant areas and release scenarios will result in improved safety. Several design alternatives which have the potential to significantly reduce the probability of a large release of LNG occurring at an import terminal are identified. These design alternatives would reduce the probability of a large release of LNG by reducing the expected number of failures which could cause a release or by reducing the magnitude of releases that do occur. All of these alternatives are technically feasible and have been used or considered for use in at least one LNG facility. A more rigorous analysis of the absolute risk of LNG import terminal operation is necessary before the benefits of these design alternatives can be determined. In addition, an economic evaluation of these alternatives must be made so the costs and benefits can be compared. It is concludd that for remotely located facilities many of these alternatives are probably not justified; however, for facilities located in highly populated areas, these alternatives deserve serious consideration.

Baker, E G

1982-04-01

105

Interim qualitative risk assessment for an LNG refueling station and review of relevant safety issues  

SciTech Connect

This report is a qualitative assessment of the public and worker risk involved with the operation of a liquefied natural (LNG) vehicle refueling facility. This study includes facility maintenance and operations, tanker truck delivers and end-use vehicle fueling; it does not treat the risks of LNG vehicles on roadways. Accident initiating events are identified by using a Master Logic Diagram, a Failure Modes and Effects analysis and historical operating experiences. The event trees were drawn to depict possible sequences of mitigating events following the initiating events. The phenomenology of LNG and other vehicle fuels is discussed to characterize the hazard posed by LNG usage. Based on the risk modeling and analysis, recommendations are given to improve the safety of LNG refueling stations in the areas of procedures and training, station design, and the dissemination of best practice information throughout the LNG community.

Siu, N.; Herring, S.; Cadwallader, L.; Reece, W.; Byers, J.

1997-07-01

106

Qualitative Risk Assessment for an LNG Refueling Station and Review of Relevant Safety Issues  

SciTech Connect

This report is a qualitative assessment of the public and worker risk involved with the operation of a liquefied natural gas (LNG) vehicle refueling facility. This study includes facility maintenance and operations, tank truck deliveries, and end-use vehicle fueling; it does not treat the risks of LNG vehicles on roadways. Accident initiating events are identified by using a Master Logic Diagram, a Failure Modes and Effects Analysis, and historical operating experiences. The event trees were drawn to depict possible sequences of mitigating events following the initiating events. The phenomenology of LNG and other vehicle fuels is discussed to characterize the hazard posed by LNG usage. Based on the risk modeling and analysis, recommendations are given to improve the safety of LNG refueling stations in the areas of procedures and training, station design, and the dissemination of ``best practice`` information throughout the LNG community.

Siu, N.; Herring, J.S.; Cadwallader, L.; Reece, W.; Byers, J.

1998-02-01

107

40 CFR Table W - 5 of Subpart W of Part 98-Default Methane Emission Factors for Liquefied Natural Gas (LNG) Storage  

Code of Federal Regulations, 2013 CFR

...Methane Emission Factors for Liquefied Natural Gas (LNG) Storage W Table W...GREENHOUSE GAS REPORTING Petroleum and Natural Gas Systems Definitions. Pt...Methane Emission Factors for Liquefied Natural Gas (LNG) Storage LNG...

2013-07-01

108

Kalimantan field development hikes gas supply for LNG export  

SciTech Connect

This paper reports on the development of Tambora and Tunu gas fields in Kalimantan that have increased available gas supply for the export of liquefied natural gas (LNG) from Indonesia. The demand for LNG is increasing in the energy thirsty Far East market. And Indonesia, the world's largest exporter, is keeping pace by expanding the Bontang liquefaction plant in East Kalimantan. A fifth train, with a capacity of around 2.5 million tons/year, began operating in January 1990. Start-up of a sixth train, of identical capacity, is planned for January 1994. The Bontang plant is operated by PT Badak on behalf of Pertamina, the Indonesian state oil and gas mining company. The feed to the fifth train comes primarily from the first-phase development of Total Indonesie's two gas fields, Tambora and Tunu. The sixth train will be fed by a second-phase development of the Tunu field.

Suharmoko, G.R. (Total Indonesie, Balikpapan (ID))

1991-10-14

109

The role of consequence modeling in LNG facility siting.  

PubMed

Liquefied natural gas (LNG) project modeling focuses on two primary issues, facility siting and the physical layout of element spacing. Modeling often begins with an analysis of these issues, while ensuring code compliance and sound engineering practice. The most commonly performed analysis involves verifying compliance with the siting provisions of NFPA 59A, which primarily concern property-line spacing (offsite hazard impacts). If the facility is located in the US, compliance with 49 CFR 193 is also required. Other consequence modeling is often performed to determine the spacing of elements within the facility (onsite hazard impacts). Often, many issues concerning in-plant spacing are addressed with the guidance provided in Europe's LNG standard, EN-1473. Spacing of plant buildings in relation to process areas is also a concern as analyzed using the approach given in API RP 752. Studies may also include probabilistic analysis, depending on the perceived risk and cost of mitigation. PMID:16934395

Taylor, Dennis W

2007-04-11

110

Dual fuel development for an LNG marine engine  

SciTech Connect

A dual-fuel conversion for the 3406-B Caterpillar marine diesel engine has been developed. The purpose of this conversion is to use lower priced natural gas as a fuel, thus providing substantial cost savings for large fuel consumers. Details of the conversion system are given. Data is presented showing fuel consumption, conditions leading to engine knock, conditions promoting methane flame propagation, and air-fuel ratios required for efficient combustion. The system resulting from this study will use Liquefied Natural Gas (LNG) to power a dual-fuel conversion of a shrimp boat's main engine and generator set. The cold temperatures of the LNG will also be used as a heat sink to refrigerate the fish-hold area of the boat.

Acker, G.H.

1988-01-01

111

LNG Vehicle High-Pressure Fuel System and ''Cold Energy'' Utilization  

Microsoft Academic Search

A high-pressure fuel system for LNG vehicles with direct-injection natural gas engines has been developed and demonstrated on a heavy-duty truck. A new concept for utilizing the ''cold energy'' associated with LNG vehicles to generate mechanical power to drive auxiliary equipment (such as high-pressure fuel pumps) has also been developed and demonstrated in the laboratory. The high-pressure LNG fuel system

Charles A. powers; T. Craig Derbidge

2001-01-01

112

Coupling dynamic blow down and pool evaporation model for LNG.  

PubMed

Treating the dynamic effects of accidental discharges of liquefied natural gas (LNG) is important for realistic predictions of pool radius. Two phenomena have important influence on pool spread dynamics, time-varying discharge (blow down) and pool ignition. Time-varying discharge occurs because a punctured LNG tanker or storage tank drains with a decreasing liquid head and decreasing head-space pressure. Pool ignition increases the evaporation rate of a pool and consequently decreases the ultimate pool area. This paper describes an approach to treat these phenomena in a dynamic pool evaporation model. The pool evaporation model developed here has two separate regimes. Early in the spill, momentum forces dominate and the pool spreads independently of pool evaporation rate and the corresponding heat transfer rate. After the average pool depth drops below a minimum value, momentum forces are largely dissipated and the thin edges of the pool completely evaporate, so pool area is established by the heat transfer rate. The maximum extent of a burning pool is predicted to be significantly less than that of an unignited pool because the duration of the first regime is reduced by higher heat transfer rates. The maximum extent of an LNG pool is predicted to be larger upon accounting for blow down compared with using a constant average discharge rate. However, the maximum pool extent occurs only momentarily before retreating. PMID:17184912

Woodward, John L

2007-02-20

113

Vapor Barrier Assessment Program for delaying and diluting heavier-than-air HF vapor clouds---A review of previous related work  

SciTech Connect

The overall purpose of this three phase study (note: the second phase deals with cloud flammability concerns and is not a part of the CPP project) is to assess the effect of vapor barriers in diluting and delaying heavier-than-air (HTA) hydrogen fluoride (HF) vapor clouds. The first phase, which is the subject of this report, consisted of obtaining, reviewing and analyzing existing field and laboratory data bases. Three data bases (Thorney Island Phase 1, 2, and 3 Heavy Gas Dispersion Trails, Neff and Meroney (1986) pre-field wind tunnel tests for the Falcon LNG field tests, and Petersen and Ratcliff (1988) API surface roughness effects evaluation) were analyzed. For the Thorney Island and Neff and Marionette data bases, continuous concentrations were measured so that peak concentrations, peak arrival times, cloud arrival times and cloud durations could be assessed. For the Petersen and Ratcliff data base, continuous released were evaluated and average concentrations were measured; therefore, peak times, etc. could not be evaluated. From the Thorney Island data base, the effect of the following obstructions could be assessed: (a) a 5 m semi-circular fence; (b) a 9 m isolated cubic building up and downwind of the release; (c) a semi-circular 10 m porous screen; and (d) a 2.4 rectangular enclosure. The Neff and Meroney (1986) data base studied the effect of a 44 by 88 m enclosure with a 9.4 m height and 14.1 and 9.4 m vortex-generating walls directly upwind of the release. The Petersen and Ratcliff (1988) data base studied the effect of natural occurring barriers (designated as the API tank farm and API process unit) and homogeneous type surface roughness ranging from grasslands to the center of a city. 16 refs., 45 figs., 9 tabs.

Petersen, R.L.; Ratcliff, M.A.

1988-10-01

114

Study of the Dispersive Potential of Irradiated Fuel Using in-Core Experiments.  

National Technical Information Service (NTIS)

Under prompt burst conditions the work potential of expanding fuel vapor is a sensitive function of the ability of fission product gases to cause fuel dispersal milliseconds before dispersal would occur from fuel vapor pressure alone. This relation is of ...

D. H. Worledge G. L. Cano

1979-01-01

115

Chemical Vapor Synthesis of Niobium Aluminides.  

National Technical Information Service (NTIS)

Chemical vapor deposition of niobium aluminides, niobium silicides, metal-rich compositions containing dispersed metallic phases, and ternary compositions in the titanium-niobium aluminum system was performed by several techniques. Process chemistry model...

G. H. Reynolds J. Chin J. H. Norman

1992-01-01

116

76 FR 33746 - Freeport LNG Development, L.P.; Application for Blanket Authorization To Export Liquefied Natural...  

Federal Register 2010, 2011, 2012, 2013

...LNG states that traditional domestic natural gas production has been supplemented by unconventional sources, such as shale gas formations, which new technologies have made economically recoverable. Freeport LNG asserts that as a result of...

2011-06-09

117

LNG (liquefied natural gas) in the Asia-Pacific region: Twenty years of trade and outlook for the future  

SciTech Connect

This report discusses the following topics: the current status of LNG trade in the Asia-Pacific region; present structure and projected demand in the Asia-Pacific region; prospective and tentative projects; and LNG contracts: stability versus flexibility.

Kiani, B.

1990-01-01

118

33 CFR 165.1709 - Security Zones: Liquefied Natural Gas Tanker Transits and Operations at Phillips Petroleum LNG...  

Code of Federal Regulations, 2013 CFR

...Tanker Transits and Operations at Phillips Petroleum LNG Pier, Cook Inlet, AK. 165...Tanker Transits and Operations at Phillips Petroleum LNG Pier, Cook Inlet, AK. (a...Cook Inlet, Alaska between the Phillips Petroleum LNG Pier, 60°40â²43â³ N and...

2013-07-01

119

Thermal design of coil-wound LNG heat exchangers. Shell-side heat transfer and pressure drop.  

National Technical Information Service (NTIS)

The main objectives for the work presented in this thesis have been to develop calculation models for LNG (Liquefied Natural Gas) heat exchangers and LNG liquefaction cycles, in order to do realistic simulations of LNG plants. The thesis consists of three...

A. O. Fredheim

1994-01-01

120

Tests at the FOS Terminal on the LNG Behavior in Large Tanks.  

National Technical Information Service (NTIS)

The determination of the recovery process of the evaporation gases of the LNG tanks and the setting of rational operating methods imply the exact knowledge of the LNG behavior during its storage. The theoretical studies carried out in this direction did n...

C. Bonnaure F. Bellus L. Chevalier Y. Reveillard

1978-01-01

121

LNG dilemma: the need is great but so are the risks  

Microsoft Academic Search

Dr. Edward Teller cites the hazards of LNG, but at the moment there are no alternatives. According to the American Gas Association, imported LNG offers that potential of providing 3 trillion cubic feet of natural gas by 1985. This represents 3 percent of total U.S. energy needs forecast for that year by the Federal Energy Administration and 12 to 15

Beiser

1976-01-01

122

Research for developing the program(II) of Estimating LNG/NG physical properties.  

National Technical Information Service (NTIS)

After liquefied natural gas(LNG) has been imported since 1986 to reduce our national primary energy dependence on petroleum and to give variety utilization, the annual demand of LNG has been getting increased due to its convenience and absence of air poll...

H. Kim S. Y. Kim

1994-01-01

123

Thermodynamic Processes Involving Liquefied Natural Gas at the LNG Receiving Terminals / Procesy termodynamiczne z wykorzystaniem skroplonego gazu ziemnego w terminalach odbiorczych LNG  

NASA Astrophysics Data System (ADS)

The increase in demand for natural gas in the world, cause that the production of liquefied natural gas (LNG) and in consequences its regasification becoming more common process related to its transportation. Liquefied gas is transported in the tanks at a temperature of about 111K at atmospheric pressure. The process required to convert LNG from a liquid to a gas phase for further pipeline transport, allows the use of exergy of LNG to various applications, including for electricity generation. Exergy analysis is a well known technique for analyzing irreversible losses in a separate process. It allows to specify the distribution, the source and size of the irreversible losses in energy systems, and thus provide guidelines for energy efficiency. Because both the LNG regasification and liquefaction of natural gas are energy intensive, exergy analysis process is essential for designing highly efficient cryogenic installations. Wzrost zapotrzebowania na gaz ziemny na ?wiecie powoduje, ?e produkcja skroplonego gazu ziemnego (LNG), a w konsekwencji jego regazyfikacja, staje si? coraz bardziej powszechnym procesem zwi?zanym z jego transportem. Skroplony gaz transportowany jest w zbiornikach w temperaturze oko?o 111K pod ci?nieniem atmosferycznym. Przebieg procesu regazyfikacji niezb?dny do zamiany LNG z fazy ciek?ej w gazow? dla dalszego transportu w sieci, umo?liwia wykorzystanie egzergii LNG do ró?nych zastosowa?, mi?dzy innymi do produkcji energii elektrycznej. Analiza egzergii jest znan? technik? analizowania nieodwracalnych strat w wydzielonym procesie. Pozwala na okre?lenie dystrybucji, ?ród?a i wielko?ci nieodwracalnych strat w systemach energetycznych, a wi?c ustali? wytyczne dotycz?ce efektywnego zu?ycia energii. Poniewa? zarówno regazyfikacja LNG jak i skraplanie gazu ziemnego s? energoch?onne, proces analizy egzergii jest niezb?dny do projektowania wysoce wydajnych instalacji kriogenicznych.

?aciak, Mariusz

2013-06-01

124

Comparison of hypothetical LNG and fuel oil fires on water.  

PubMed

Large spills of refined petroleum products have been an occasional occurrence over the past few decades. This has not been true for large spills of liquefied natural gas (LNG). This paper compares the likely similarities and differences between accidental releases from a ship of sizable quantities of these different hydrocarbon fuels, their subsequent spreading, and possible pool-fire behavior. Quantitative estimates are made of the spread rate and maximum slick size, burn rate, and duration; effective thermal radiation; and subsequent soot generation. PMID:15036638

Lehr, William; Simecek-Beatty, Debra

2004-02-27

125

Numerical simulation of water injection into vapor-dominated reservoirs  

Microsoft Academic Search

Water injection into vapor-dominated reservoirs is a means of condensate disposal, as well as a reservoir management tool for enhancing energy recovery and reservoir life. We review different approaches to modeling the complex fluid and heat flow processes during injection into vapor-dominated systems. Vapor pressure lowering, grid orientation effects, and physical dispersion of injection plumes from reservoir heterogeneity are important

K. Pruess

1995-01-01

126

Vapor fragrancer  

NASA Astrophysics Data System (ADS)

This invention relates to a vapor fragrancer for continuously, uniformly, and economically odorizing or deodorizing an environment. Homes, offices, automobiles, and space stations require either odorizing or deodorizing of the atmosphere to create pleasant conditions for work or leisure. A vapor fragrancer is provided to accomplish these goals. A supplier continuously supplies a predetermined amount of desired liquid fragrance from a container to a retaining material, which is positioned in the circulation path of the atmosphere. The supplier is either a low powered pump or a gravity dispenser. The atmosphere flowing in a circulation path passes over the retaining material containing the liquid fragrance and lifts a fragrant vapor from the retaining material. The atmosphere is thereby continuously and uniformly fragranced.

Sang, Q. Tran; Bryant, Timothy D.

1987-05-01

127

Vapor Detector  

NASA Technical Reports Server (NTRS)

Detector eliminates need for removing covers to take samples. Detector is canister consisting of screw-in base and clear plastic tube that contains two colors of silica gel. Monoethylhydrazine and nitrogen tetroxide vapors are visually monitored with canister containing color-changing gels.

Waddell, H. M.; Garrard, G. C.; Houston, D. W.

1982-01-01

128

A review of recent field tests and mathematical modelling of atmospheric dispersion of large spills of Denser-than-air gases  

NASA Astrophysics Data System (ADS)

Large-scale spills of hazardous materials often produce gas clouds which are denser than air. The dominant physical processes which occur during dense-gas dispersion are very different from those recognized for trace gas releases in the atmosphere. Most important among these processes are stable stratification and gravity flow. Dense-gas flows displace the ambient atmospheric flow and modify ambient turbulent mixing. Thermodynamic and chemical reactions can also contribute to dense-gas effects. Some materials flash to aerosol and vapor when released and the aerosol can remain airborne, evaporating as it moves downwind, causing the cloud to remain cold and dense for long distances downwind. Dense-gas dispersion models, which include phase change and terrain effects have been developed and are capable of simulating many possible accidental releases. A number of large-scale field tests with hazardous materials such as liquefied natural gas (LNG), ammonia (NH 3), hydrofluoric acid(HF) and nitrogen tetroxide(N 2O 4) have been performed and used to evaluate models. The tests have shown that gas concentrations up to ten times higher than those predicted by trace gas models can occur due to aerosols and other dense-gas effects. A methodology for model evaluation has been developed which is based on the important physical characteristics of dense-gas releases.

Koopman, Ronald P.; Ermak, Donald L.; Chan, Stevens T.

129

Oil dispersants  

SciTech Connect

This book contains papers presented at a symposium of the American Society for Testing and Materials. The topics covered include: The effect of elastomers on the efficiency of oil spill dispersants; planning for dispersant use; field experience with dispersants for oil spills on land; and measurements on natural dispersion.

Flaherty, L.M.

1989-01-01

130

49 CFR 191.22 - National Registry of Pipeline and LNG operators.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false National Registry of Pipeline and LNG operators. 191.22 Section...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL...

2013-10-01

131

49 CFR 195.64 - National Registry of Pipeline and LNG Operators.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false National Registry of Pipeline and LNG Operators. 195.64 Section...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF...

2013-10-01

132

75 FR 70350 - Liberty Natural Gas LLC, Liberty Liquefied Natural Gas (LNG) Deepwater Port License Application  

Federal Register 2010, 2011, 2012, 2013

...Administration [USCG-2010-0993] Liberty Natural Gas LLC, Liberty Liquefied Natural Gas (LNG) Deepwater Port License Application AGENCY...received an application for the licensing of a natural gas deepwater port and the application...

2010-11-17

133

75 FR 60095 - Sempra LNG Marketing, LLC; Application for Blanket Authorization To Export Liquefied Natural Gas  

Federal Register 2010, 2011, 2012, 2013

...Authorization To Export Liquefied Natural Gas AGENCY: Office of Fossil Energy...of foreign sourced liquefied natural gas (LNG) for a two-year period...was filed under section 3 of the Natural Gas Act (NGA), as amended by...

2010-09-29

134

78 FR 35263 - Freeport LNG Development, L.P.; Application for Blanket Authorization To Export Previously...  

Federal Register 2010, 2011, 2012, 2013

...Export Previously Imported Liquefied Natural Gas on a Short-Term Basis AGENCY...authorization to export liquefied natural gas (LNG) that previously had been...24 billion cubic feet (Bcf) of natural gas on a short-term or spot...

2013-06-12

135

49 CFR 193.2013 - Incorporation by reference.  

Code of Federal Regulations, 2010 CFR

...a). (2) GTI-04/0049 (April 2004) âLNG Vapor Dispersion Prediction with the DEGADIS 2.1: Dense Gas Dispersion Model For LNG Vapor Dispersionâ § 193.2059. (3) GRI-96/0396.5 âEvaluation of Mitigation Methods...

2010-10-01

136

Columbia-Iran LNG project will have first commercial barge-mounted plant  

Microsoft Academic Search

An agreement of understanding signed by Columbia LNG Corp. and the National Iranian Gas Co. (NIGC) in Apr. 1978 provides for delivery of 300 million cu ft\\/day of gas as LNG to the Cove Point, Md., terminal for 20 yr beginning in 1982. A barge-mounted liquefaction plant is to be designed and built and 90% financed by Norway's Moss-Rosenberg Verft

1978-01-01

137

Vapor Bubble Nucleation: A Microscopic Phenomenon  

Microsoft Academic Search

In this article, vapor bubble nucleation in liquid and the evaporation process of a liquid droplet at its superheat limit\\u000a were discussed from the viewpoint of molecular clustering (molecular cluster model for bubble nucleation). For the vapor bubble\\u000a formation, the energy barrier against bubble nucleation was estimated by the molecular interaction due to the London dispersion\\u000a force. Bubble nucleation by

Ho-Young Kwak

2004-01-01

138

Zero-Emission Combined Power Cycle Using LNG Cold  

NASA Astrophysics Data System (ADS)

A potential zero emission combined power generation plant fired by liquefied natural gas (LNG) has been investigated. A mixture of carbon dioxide (CO2)-steam is used as the working fluid of a gas turbine cycle, which replaces the normal combustion-in-air products and air, notably as the thermal ballast for the control of flame temperature. Oxygen (O2) is used as the fuel oxidant and is obtained from an air separation unit (ASU). The excess CO2 due to combustion is extracted by a simple flow separator and liquefied ready to be reused and/or sequestered. The plant configuration and thermodynamics of the cycle are discussed first and then the optimised overall efficiency of the plant is calculated with a comparison of 100% and 120% stoichiometric combustion. The overall net efficiency, optimised to pressure and temperature levels complying with the material and cooling techniques currently available, is around 56% (LHV basis), including the energy penalty of the ASU and the CO2 separation.

Velautham, Sanjayan; Ito, Takehiro; Takata, Yasuyuki

139

Geologic setting and gas reserves of the Venezuelan LNG project  

SciTech Connect

Four gas fields, Mejillones, Patao, Dragon, and Rio Caribe, were discovered by Lagoven, a subsidiary of Petroleos de Venezuela S.A., during an exploratory campaign during 1978-1982, offshore northeastern Venezuela. Thirteen wells drilled in the four fields discovered 13.9 tcf of gas, including 1.2 tcf of gas and condensate in the Rio Caribe field. In February 1991, Lagoven entered into an agreement with Shell, Exxon, and Mitsubishi to assess the viability of producing and exporting gas from the four offshore gas fields in the form of liquified natural gas. This is the Venezuelan LNG Project, otherwise called the Cristobal Colon Project. As part of the agreement the participants established a Project Team in Caracas and undertook the acquisition of 1600 km[sup 2] of 3D seismic data over the four fields to evaluate the geological model of the area. In addition, interpretation of the 3D data has led to a preliminary geological model for the gas bearing sands which envisages deposition in a regional setting varying from bathyal turbidites in the Rio Caribe and Mejillones fields in the west to shelf deposits over the Patao and Dragon fields in the east. In addition to the geological setting this paper will discuss preliminary results of the reserves evaluation for the Rio Caribe, Patao, and Dragon fields.

Prieto, R.; Van der Molen, I.; Ramirez de Arellano, R. (Lagoven, Caracas (Venezuela))

1993-02-01

140

Seed Dispersal  

NSDL National Science Digital Library

In this outdoor activity and bingo-like game, learners explore why and how seeds spread far from the plants that produce them. To understand natural adaptions that let seeds and fruit be dispersed, learners make modifications to dried beans and peas so they could be dispersed by natural forces like water, air, or an animal moving from one place to another. In the "Seed-Go" Game, learners match ways that seeds are dispersed, to fill rows on the game board.

Science, Lawrence H.

1979-01-01

141

Dispersion Basics  

NSDL National Science Digital Library

In this Webcast, Dr. Timothy Spangler (Director of the COMET Program and a former air quality consultant) provides a brief overview of the basics of atmospheric dispersion and how dispersion is modeled, particularly for accidental releases of hazardous materials. The lecture is presented in six sections and covers the effects of stability, turbulence, plume rise, and wind. Basic dispersion models are discussed, along with a brief summary of models used in special situations and factors that complicate their use.

Spangler, Tim

2002-11-01

142

75 FR 11169 - AES Sparrows Point LNG, LLC; Mid-Atlantic Express, LLC; Notice of Availability of the Revised...  

Federal Register 2010, 2011, 2012, 2013

...CP07-63-000] AES Sparrows Point LNG, LLC; Mid-Atlantic Express, LLC; Notice of Availability of the Revised Draft Final General...proposed by AES Sparrows Point LNG, LLC and Mid-Atlantic Express, LLC, collectively referred to as AES, in the...

2010-03-10

143

Ocular dispersion  

NASA Astrophysics Data System (ADS)

Spectrally resolved white-light interferometry was used to measure the wavelength dependence of refractive index (i.e., dispersion) for various ocular components. The accuracy of the technique was assessed by measurement of fused silica and water, the refractive indices of which have been measured at several different wavelengths. The dispersion of bovine and rabbit aqueous and vitreous humor was measured from 400 to 1100 nm. Also, the dispersion was measured from 400 to 700 nm for aqueous and vitreous humor extracted from goat and rhesus monkey eyes. For the humors, the dispersion did not deviate significantly from water. In an additional experiment, the dispersion of aqueous and vitreous humor that had aged up to a month was compared to freshly harvested material. No difference was found between the fresh and aged media. An unsuccessful attempt was also made to use the technique for dispersion measurement of bovine cornea and lens. Future refinement may allow measurement of the dispersion of cornea and lens across the entire visible and near-infrared wavelength band. The principles of white- light interferometry including image analysis, measurement accuracy, and limitations of the technique, are discussed. In addition, alternate techniques and previous measurements of ocular dispersion are reviewed.

Hammer, Daniel X.; Noojin, Gary D.; Thomas, Robert J.; Stolarski, David J.; Rockwell, Benjamin A.; Welch, Ashley J.

1999-06-01

144

Calibrated vapor generator source  

DOEpatents

A portable vapor generator is disclosed that can provide a controlled source of chemical vapors, such as, narcotic or explosive vapors. This source can be used to test and calibrate various types of vapor detection systems by providing a known amount of vapors to the system. The vapor generator is calibrated using a reference ion mobility spectrometer. A method of providing this vapor is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the vapor pressure of the material) to control the concentration of vapors in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of vapors at the outlet.

Davies, John P. (Idaho Falls, ID); Larson, Ronald A. (Idaho Falls, ID); Goodrich, Lorenzo D. (Shelley, ID); Hall, Harold J. (Idaho Falls, ID); Stoddard, Billy D. (Idaho Falls, ID); Davis, Sean G. (Idaho Falls, ID); Kaser, Timothy G. (Idaho Falls, ID); Conrad, Frank J. (Albuquerque, NM)

1995-01-01

145

Calibrated vapor generator source  

DOEpatents

A portable vapor generator is disclosed that can provide a controlled source of chemical vapors, such as, narcotic or explosive vapors. This source can be used to test and calibrate various types of vapor detection systems by providing a known amount of vapors to the system. The vapor generator is calibrated using a reference ion mobility spectrometer. A method of providing this vapor is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the vapor pressure of the material) to control the concentration of vapors in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of vapors at the outlet. 10 figs.

Davies, J.P.; Larson, R.A.; Goodrich, L.D.; Hall, H.J.; Stoddard, B.D.; Davis, S.G.; Kaser, T.G.; Conrad, F.J.

1995-09-26

146

THERMOACOUSTIC LIQUEFACTION OF COAL MINE METHANE TO PRODUCE LNG FOR HEAVY VEHICLE APPLICAITONS  

SciTech Connect

This report describes the activity undertaken by the project members under MORGANTOWN ENERGY TECHNOLOGY CENTER (METC) contract No. DE-AC21-95MC32185 to develop a project that will provide a commercial use for Coal Mine Methane (CMM). In particular, the report describes a project to convert CMM into Liquefied Natural Gas (LNG) and to market that LNG to the transportation sector in and around the I-79 corridor near Morgantown, West Virginia. The report discusses the sources of CMM and provides estimates of the extent of the resource specifically dedicated to the project. It discusses the novel refrigeration technology that will be employed to convert the CMM to LNG and the gas conditioning technology that will be used to bring the raw CMM up to cryogenic processing specifications. Summary capital and operating cost estimates are furnished for the project and specific monetary and schedule requirements are identified so the project can be examined in its entirety. The report discusses the immediate market potential for the successful commercial sale of LNG into the nearby market and provides estimates of future market penetration into local, regional and wider markets. Lastly, the report comments on the environmental effects of the project and extrapolates these benefits to future markets. One of the driving forces for the project is the reduction of environmentally harmful greenhouse gases currently escaping unchecked into the atmosphere. This final section analyzes the TASHER technology's potential net environmental benefits both in terms of greenhouse gases and criteria pollutants.

Dr. Kashi Aminian; Dr. Lloyd English; Dr. Douglas Patchen; Dr. Hema Siriwardane; Charles D. Estes; Raymond L. Zahradnik

1999-10-29

147

Environmental Review of the Proposed Cove Point LNG Facility ASU Project.  

National Technical Information Service (NTIS)

The Maryland Public Service Commission (PSC) has granted a Certificate of Public Convenience and Necessity (CPCN) to Dominion Cove Point LNG, L.P. (PSC Order No. 80998) to construct an Air Separation Unit (ASU) Project at Cove Point, its liquefied natural...

C. Faustini D. Mountain J. Flannery J. Ross M. Garrospm

2009-01-01

148

LIQUID NATURAL GAS (LNG): AN ALTERNATIVE FUEL FROM LANDFILL GAS (LFG) AND WASTEWATER DIGESTER GAS  

SciTech Connect

This Research and Development Subcontract sought to find economic, technical and policy links between methane recovery at landfill and wastewater treatment sites in New York and Maryland, and ways to use that methane as an alternative fuel--compressed natural gas (CNG) or liquid natural gas (LNG) -- in centrally fueled Alternative Fueled Vehicles (AFVs).

VANDOR,D.

1999-03-01

149

Water Vapor Imagery: Water Vapor Imagery Basics  

NSDL National Science Digital Library

This self-paced, interactive tutorial enables learners to discover practical uses for water vapor imagery from weather satellites. The module introduces the concept and function of the water vapor channel of satellite imagery, and teaches how to interpret and apply data obtained from the water vapor channel. At the end of the tutorial, links are provided to real world data collected by NASA satellites where learners can apply the skills they have acquired. This resource is part of the tutorial series, Satellite Observations in Science Education, and is the first of three modules in the tutorial, Water Vapor Imagery. (Note: requires Java plug-in)

150

Three-dimensional model for simulating atmospheric dispersion of heavy-gases over complex terrain  

SciTech Connect

To help understand heavy gas releases and simulate the resultant dispersion, we have developed a three-dimensional finite element model called FEM3 and an improved version names FEM3A for solving the time dependent conservation equations based on generalized anelastic approximation. Recent enhancements to the model to include the treatment of dispersion scenarios involving density variations much larger than the liquefied natural gas range and an advanced turbulence submodel based on the buoyancy-extended transport equations. This paper presents the main features of the present model FEM3C and numerical results from the simulations of a field-scale LNG spill experiment.

Chan, S.T.

1997-09-01

151

Explosives Vapor Characterization.  

National Technical Information Service (NTIS)

The vaporous emissions from seventeen explosives were investigated by gas chromatographic and combined gas chromatographic/mass spectrometric techniques using a novel collection device. The vapor emission rates were followed as a function of time untile t...

F. H. Jarke S. M. Gordon

1982-01-01

152

Vapor Pressure of GD.  

National Technical Information Service (NTIS)

The vapor pressure of pinacolyl methyl phosphonofluoridate O-(I ,2, 2-trimethylpropyl)-methyl phosphonofluoridate. GD has been measured between - 20 and 50 C, using vapor saturation methodology. The current data are in good agreement with data previously ...

A. Balboa D. E. Tevault J. H. Buchanan L. C. Buettner T. Sewell

2007-01-01

153

76 FR 76698 - Dominion Cove Point LNG, LP; Application To Export Domestic Liquefied Natural Gas to Non-Free...  

Federal Register 2010, 2011, 2012, 2013

...exist to satisfy domestic demand as well as the proposed LNG exports. DCP notes that the recent phenomenon of domestic shale gas has increased gas reserves and, consequently, gas production levels are projected to continue to grow steadily....

2011-12-08

154

77 FR 55197 - LNG Development Company, LLC; Application for Long-Term Authorization To Export Liquefied Natural...  

Federal Register 2010, 2011, 2012, 2013

...production, owing to drilling productivity gains that enabled rapid growth in supplies from unconventional, and particularly shale, gas-bearing formations in the United States and Canada. Oregon LNG states that improvements in drilling and...

2012-09-07

155

75 FR 68347 - Sabine Pass Liquefaction LLC, and Sabine Pass LNG, L.P.; Notice of Intent To Prepare an...  

Federal Register 2010, 2011, 2012, 2013

...owing to drilling productivity gains that have enabled rapid growth in supplies from unconventional, and particularly shale, gas-bearing formations in the United States. The exportation of LNG would provide a market solution to allow the...

2010-11-05

156

78 FR 17189 - Trunkline LNG Export, LLC; Application for Long-Term Authorization to Export Liquefied Natural...  

Federal Register 2010, 2011, 2012, 2013

...Long-Term Authorization to Export Liquefied Natural Gas Produced from Domestic Natural Gas Resources to Non-Free Trade Agreement Countries...authorization to export domestically produced liquefied natural gas (LNG) in an amount up to of 15 million...

2013-03-20

157

Demand management of city gas per season and study of estimating proper size of LNG storage facilities.  

National Technical Information Service (NTIS)

LNG storage facilities are indispensable to satisfy demand throughout the year by saturating the time difference of supply and demand that appears due to seasonal factors. The necessity of storage facilities is more important in a country like Korea where...

Y. H. Jung S. D. Kim

1997-01-01

158

18 CFR 157.21 - Pre-filing procedures and review process for LNG terminal facilities and other natural gas...  

Code of Federal Regulations, 2010 CFR

...which Commission staff may make a selection to assist in the preparation of the requisite NEPA document. (9) For natural gas facilities other than LNG terminal...which Commission staff may make a selection to assist in the preparation...

2010-04-01

159

18 CFR 157.21 - Pre-filing procedures and review process for LNG terminal facilities and other natural gas...  

Code of Federal Regulations, 2010 CFR

...which Commission staff may make a selection to assist in the preparation of the requisite NEPA document. (9) For natural gas facilities other than LNG terminal...which Commission staff may make a selection to assist in the preparation...

2009-04-01

160

D-optimal experimental design coupled with parallel factor analysis 2 decomposition a useful tool in the determination of triazines in oranges by programmed temperature vaporization-gas chromatography-mass spectrometry when using dispersive-solid phase extraction.  

PubMed

The determination of triazines in oranges using a GC-MS system coupled to a programmed temperature vaporizer (PTV) inlet in the context of legislation is performed. Both pretreatment (using a Quick Easy Cheap Effective Rugged and Safe (QuEChERS) procedure) and injection steps are optimized using D-optimal experimental designs for reducing the experimental effort. The relative dirty extracts obtained and the elution time shifts make it necessary to use a PARAFAC2 decomposition to solve these two usual problems in the chromatographic determinations. The "second-order advantage" of the PARAFAC2 decomposition allows unequivocal identification according to document SANCO/12495/2011 (taking into account the tolerances for relative retention time and the relative abundance for the diagnostic ions), avoiding false negatives even in the presence of unknown co-eluents. The detection limits (CC?) found, from 0.51 to 1.05?gkg(-1), are far below the maximum residue levels (MRLs) established by the European Union for simazine, atrazine, terbuthylazine, ametryn, simetryn, prometryn and terbutryn in oranges. No MRL violations were found in the commercial oranges analyzed. PMID:23522618

Herrero, A; Ortiz, M C; Sarabia, L A

2013-05-01

161

Colloidal Dispersions  

Microsoft Academic Search

The book covers the physical side of colloid science from the individual forces acting between submicron particles suspended in a liquid through the resulting equilibrium and dynamic properties. The relevant forces include Brownian motion, electrostatic repulsion, dispersion attraction, both attraction and repulsion due to soluble polymer, and viscous forces due to relative motion between the particles and the liquid. The

W. B. Russel; D. A. Saville; W. R. Schowalter

1992-01-01

162

Comparative life-cycle air emissions of coal, domestic natural gas, LNG, and SNG for electricity generation.  

PubMed

The U.S. Department of Energy (DOE) estimates that in the coming decades the United States' natural gas (NG) demand for electricity generation will increase. Estimates also suggest that NG supply will increasingly come from imported liquefied natural gas (LNG). Additional supplies of NG could come domestically from the production of synthetic natural gas (SNG) via coal gasification-methanation. The objective of this study is to compare greenhouse gas (GHG), SOx, and NOx life-cycle emissions of electricity generated with NG/LNG/SNG and coal. This life-cycle comparison of air emissions from different fuels can help us better understand the advantages and disadvantages of using coal versus globally sourced NG for electricity generation. Our estimates suggest that with the current fleet of power plants, a mix of domestic NG, LNG, and SNG would have lower GHG emissions than coal. If advanced technologies with carbon capture and sequestration (CCS) are used, however, coal and a mix of domestic NG, LNG, and SNG would have very similar life-cycle GHG emissions. For SOx and NOx we find there are significant emissions in the upstream stages of the NG/ LNG life-cycles, which contribute to a larger range in SOx and NOx emissions for NG/LNG than for coal and SNG. PMID:17937317

Jaramillo, Paulina; Griffin, W Michael; Matthews, H Scott

2007-09-01

163

Vapor phase pyrolysis  

NASA Technical Reports Server (NTRS)

The vapor phase pyrolysis process is designed exclusively for the lunar production of oxygen. In this concept, granulated raw material (soil) that consists almost entirely of metal oxides is vaporized and the vapor is raised to a temperature where it dissociates into suboxides and free oxygen. Rapid cooling of the dissociated vapor to a discrete temperature causes condensation of the suboxides, while the oxygen remains essentially intact and can be collected downstream. The gas flow path and flow rate are maintained at an optimum level by control of the pressure differential between the vaporization region and the oxygen collection system with the aid of the environmental vacuum.

Steurer, Wolfgang

1992-01-01

164

Stratospheric water vapor feedback  

PubMed Central

We show here that stratospheric water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that stratospheric water vapor increases with tropospheric temperature, implying the existence of a stratospheric water vapor feedback. We estimate the strength of this feedback in a chemistry–climate model to be +0.3 W/(m2?K), which would be a significant contributor to the overall climate sensitivity. One-third of this feedback comes from increases in water vapor entering the stratosphere through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause.

Dessler, A. E.; Schoeberl, M. R.; Wang, T.; Davis, S. M.; Rosenlof, K. H.

2013-01-01

165

Survey of fire-protection systems at LNG facilities. Topical report, July-November 1990  

SciTech Connect

The objectives of the study were to collect and analyze data relating to the types, costs, and operational problems of gas leak and fire detection devices and of fire prevention and suppression systems used at LNG facilities operating in the United States. Data from 39 LNG facilities, which accounted for 45% of the total U.S. storage capacity, were collected. The report provides information relating to equipment manufacturers, site applications, operational problems, initial installation costs, annual operational costs, and equipment lifetime. Equipment of interest included fixed gas leak, fire and cryogenic detection systems, water deluge and barrier systems, thermal radiation walls and protective coatings, and fixed high expansion foam, dry chemical, carbon dioxide and halon fire suppression systems. In addition, internal fire fighting capabilities were reviewed.

Atallah, S.; Borows, K.A.

1991-04-05

166

Fog dispersion  

NASA Technical Reports Server (NTRS)

A study of economically viable techniques for dispersing warm fog at commercial airports is presented. Five fog dispersion techniques are examined: evaporation suppression, downwash, mixing, seeding with hygroscopic material, thermal techniques, and charged particle techniques. Thermal techniques, although effective, were found to be too expensive for routine airport operations, and detrimental to the environment. Seeding or helicopter downwash are practical for small-scale or temporary fog clearing, but are probably not useful for airport operations on a routine basis. Considerable disagreement exists on the capability of charged particle techniques, which stems from the fact that different assumptions and parameter values are used in the analytical models. Recommendations resulting from the review of this technique are listed, and include: experimental measurements of the parameters in question; a study to ascertain possible safety hazards, such as increased electrical activity or fuel ignition during refueling operations which could render charged particle techniques impractical; and a study of a single charged particle generator.

Frost, W.; Christensen, L. S.; Collins, F. G.; Camp, D. W.

1980-01-01

167

Australian LNG plant debottlenecked to 7.5 million tons\\/year  

Microsoft Academic Search

The North West Shelf gas project, Karratha, Western Australia, has successfully carried out a three-train LNG plant debottlenecking to increase capacity from 6.9 million metric tons\\/year (mty) to more than 7.5 mty. The two major constraints targeted by the project were the COâ-removal column and the main refrigerant compressor drivers. Replacement of the original trays by structured packing in the

W. J. Brehaut; M. J. Concannon

1996-01-01

168

Cost-effectiveness analysis of levonorgestrel-releasing intrauterine system (LNG-IUS) 13.5mg in contraception  

PubMed Central

Background LNG-IUS 13.5mg (total content) is a low-dose levonorgestrel intrauterine system for up to three years of use. This analysis evaluated the cost-effectiveness of LNG-IUS 13.5mg in comparison with short-acting reversible contraceptive (SARC) methods in a cohort of young women in the US from a third-party payer’s perspective. Study Design A state-transition model consisting of three mutually exclusive health states – initial method, unintended pregnancy (UP) and subsequent method – was developed. Cost-effectiveness of LNG-IUS 13.5mg was assessed versus SARC methods in a cohort of 1,000 women aged 20–29 years. SARC methods comprise oral contraceptives (OC), ring, patch and injections which are the methods commonly used by this cohort. Failure and discontinuation probabilities were based on published literature, contraceptive uptake was determined by the most recent data from the National Survey of Family Growth and costs were taken from standard US databases. One-way sensitivity analysis was conducted around key inputs while scenario analysis assessed a comparison between LNG-IUS 13.5mg and the existing IUS, LNG-IUS 20mcg/24 hours. The key model output was cost per UP avoided. Results Compared to SARC methods, initiating contraception with LNG-IUS 13.5mg resulted in fewer UP (64 UP vs. 276 UP) and lower total costs ($1,283,479 USD vs. $1,862,633 USD, a 31% saving) over the three-year time horizon. Results were most sensitive to the probability of failure on OC, the probability of LNG-IUS 13.5mg discontinuation and the cost of live births. Scenario analysis suggests that further cost savings may be generated with the initiation of LNG-IUS 20mcg/24 hours in place of SARC methods. Conclusions From a third-party payer perspective, LNG-IUS 13.5mg is a more cost-effective contraceptive option than SARC. Therefore, women switching from current SARC use to LNG-IUS 13.5mg are likely to generate cost savings to third-party healthcare payers, driven principally by decreased UP-related expenditures and long-term savings in contraceptive costs.

Trussell, James; Hassan, Fareen; Henry, Nathaniel; Pocoski, Jennifer; Law, Amy; Filonenko, Anna

2014-01-01

169

Vapor spill monitoring method  

DOEpatents

Method for continuous sampling of liquified natural gas effluent from a spill pipe, vaporizing the cold liquified natural gas, and feeding the vaporized gas into an infrared detector to measure the gas composition. The apparatus utilizes a probe having an inner channel for receiving samples of liquified natural gas and a surrounding water jacket through which warm water is flowed to flash vaporize the liquified natural gas.

Bianchini, Gregory M. (Livermore, CA); McRae, Thomas G. (Livermore, CA)

1985-01-01

170

LNG Safety Research: FEM3A Model Development  

SciTech Connect

Work continued to address numerical problems experienced with simulation of low-wind-speed, stable, atmospheric conditions with FEM3A. Steps 1 through 8 in the plan outlined in the first Quarterly report have been completed successfully for the FEM3A model utilizing the Planetary Boundary Layer (PBL) turbulence closure model. Researchers at the University of Arkansas have solved the problems related to stability of the simulations at regulatory conditions of low wind speed and stable atmospheric conditions with FEM3A using the PBL model, and are continuing our program to verify the operation of the model using an updated, verified, version of the k-epsilon turbulence closure model which has been modified to handle dense gas dispersion effects. This quarterly report for DE-FG26-04NT42030 covers a period from January 1, 2006 to March 31, 2006. GTI's activities during the report quarter were limited to administrative work. The work at the University of Arkansas continued in line with the initial scope of work and the identified questions regarding surface to cloud heat transfer as being largely responsible for the instability problems previously encountered. A brief summary of results is discussed in this section and the complete report from University of Arkansas is attached.

Iraj A Salehi; Jerry Havens; Tom Spicer

2006-05-01

171

Vapor core turbulence in annular two-phase flow  

SciTech Connect

This paper reports a new technique to measure vapor turbulence in two-phase flows using hot-film anemometry. Continuous vapor turbulence measurements along with local void fraction, droplet frequency, droplet velocity and droplet diameter were measured in a thin, vertical duct. By first eliminating the portion of the output voltage signal resulting from the interaction of dispersed liquid droplets with the HFA sensor, the discrete voltage samples associated with the vapor phase were separately analyzed. The data revealed that, over the range of liquid droplet sizes and concentrations encountered, the presence of the droplet field acts to enhance vapor turbulence. In addition, there is evidence that vapor turbulence is significantly influenced by the wall-bounded liquid film. The present results are qualitatively consistent with the limited data available in the open literature.

Trabold, T.A.; Kumar, R. [Lockheed Martin Corp., Schenectady, NY (United States)

1998-06-01

172

Petroleum Vapor - Field Technical  

EPA Science Inventory

The screening approach being developed by EPA OUST to evaluate petroleum vapor intrusion (PVI) requires information that has not be routinely collected in the past at vapor intrusion sites. What is the best way to collect this data? What are the relevant data quality issues and ...

173

Chemical Vapor Deposition Growth.  

National Technical Information Service (NTIS)

A chemical vapor deposition (CVD) reactor system with a vertical deposition chamber was used for the growth of Si films on glass, glass-ceramic, and polycrystalline ceramic substrates. Silicon vapor was produced by pyrolysis of SiH4 in a H2 or He carrier ...

R. P. Ruth, H. M. Manasevit, J. L. Kenty, L. A. Moudy, W. I. Simpson

1976-01-01

174

78 FR 25074 - Elba Liquefaction Company, L.L.C., Southern LNG Company, L.L.C., Elba Express Company, L.L.C...  

Federal Register 2010, 2011, 2012, 2013

...Southern LNG Company, L.L.C., Elba Express Company, L.L.C.; Notice of Intent...LNG Company, LLC (SLNG); and Elba Express Company, LLC (EEC, collectively referred...add compression along its existing Elba Express Pipeline in Georgia. These...

2013-04-29

175

Piezoelectric trace vapor calibrator  

SciTech Connect

The design and performance of a vapor generator for calibration and testing of trace chemical sensors are described. The device utilizes piezoelectric ink-jet nozzles to dispense and vaporize precisely known amounts of analyte solutions as monodisperse droplets onto a hot ceramic surface, where the generated vapors are mixed with air before exiting the device. Injected droplets are monitored by microscope with strobed illumination, and the reproducibility of droplet volumes is optimized by adjustment of piezoelectric wave form parameters. Complete vaporization of the droplets occurs only across a 10 deg. C window within the transition boiling regime of the solvent, and the minimum and maximum rates of trace analyte that may be injected and evaporated are determined by thermodynamic principles and empirical observations of droplet formation and stability. By varying solution concentrations, droplet injection rates, air flow, and the number of active nozzles, the system is designed to deliver--on demand--continuous vapor concentrations across more than six orders of magnitude (nominally 290 fg/l to 1.05 {mu}g/l). Vapor pulses containing femtogram to microgram quantities of analyte may also be generated. Calibrated ranges of three explosive vapors at ng/l levels were generated by the device and directly measured by ion mobility spectrometry (IMS). These data demonstrate expected linear trends within the limited working range of the IMS detector and also exhibit subtle nonlinear behavior from the IMS measurement process.

Verkouteren, R. Michael; Gillen, Greg; Taylor, David W. [Surface and Microanalysis Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); MicroFab Technologies, Inc., 1104 Summit Avenue, Suite 110, Plano, Texas 75074 (United States)

2006-08-15

176

Piezoelectric trace vapor calibrator  

NASA Astrophysics Data System (ADS)

The design and performance of a vapor generator for calibration and testing of trace chemical sensors are described. The device utilizes piezoelectric ink-jet nozzles to dispense and vaporize precisely known amounts of analyte solutions as monodisperse droplets onto a hot ceramic surface, where the generated vapors are mixed with air before exiting the device. Injected droplets are monitored by microscope with strobed illumination, and the reproducibility of droplet volumes is optimized by adjustment of piezoelectric wave form parameters. Complete vaporization of the droplets occurs only across a 10 °C window within the transition boiling regime of the solvent, and the minimum and maximum rates of trace analyte that may be injected and evaporated are determined by thermodynamic principles and empirical observations of droplet formation and stability. By varying solution concentrations, droplet injection rates, air flow, and the number of active nozzles, the system is designed to deliver-on demand-continuous vapor concentrations across more than six orders of magnitude (nominally 290 fg/l to 1.05 ?g/l). Vapor pulses containing femtogram to microgram quantities of analyte may also be generated. Calibrated ranges of three explosive vapors at ng/l levels were generated by the device and directly measured by ion mobility spectrometry (IMS). These data demonstrate expected linear trends within the limited working range of the IMS detector and also exhibit subtle nonlinear behavior from the IMS measurement process.

Verkouteren, R. Michael; Gillen, Greg; Taylor, David W.

2006-08-01

177

Measurement of vapor superheat in post-critical-heat-flux boiling  

Microsoft Academic Search

A differentially-aspirated superheat probe was developed to measure vapor temperatures in post-critical-heat-flux, dispersed-flow boiling. Measurements obtained for water, at low-to-moderate pressures and mass flow rates in a tube, indicated very significant nonequilibrium, with vapor superheats of several hundred degrees (°C). Predictions of published correlations showed unsatisfactory agreement with the experimental results.

S. Nijhawan; J. C. Chen; R. K. Sundaram; E. J. London

1980-01-01

178

AMTEC vapor-vapor series connected cells  

NASA Technical Reports Server (NTRS)

An alkali metal thermoelectric converter (AMTEC) having a plurality of cells structurally connected in series to form a septum dividing a plenum into two chambers, and electrically connected in series, is provided with porous metal anodes and porous metal cathodes in the cells. The cells may be planar or annular, and in either case a metal alkali vapor at a high temperature is provided to the plenum through one chamber on one side of the wall and returned to a vapor boiler after condensation at a chamber on the other side of the wall in the plenum. If the cells are annular, a heating core may be placed along the axis of the stacked cells. This arrangement of series-connected cells allows efficient generation of power at high voltage and low current.

Underwood, Mark L. (inventor); Williams, Roger M. (inventor); Ryan, Margaret A. (inventor); Nakamura, Barbara J. (inventor); Oconnor, Dennis E. (inventor)

1995-01-01

179

Pressure Effects of Homogeneous Rubidium Vapor on Its Resonance Lines  

Microsoft Academic Search

The broadening of the resonance lines of rubidium in absorption under pressures up to 150 mm of its own homogeneous vapor was studied by means of a 21-foot grating. Under pressures below 1 mm the broadening of the lines was very symmetrical and the line contours could be described by the dispersion formula, but when the pressure was high the

Ch'en Shang-Yi

1940-01-01

180

Chemical vapor infiltration.  

National Technical Information Service (NTIS)

Continuous filament ceramic composites are enabling new, high temperature structural applications. Chemical vapor infiltration methods for producing these composites are being studied, with the complexity of filament weaves and deposition chemistry merged...

T. M. Besmann D. P. Stinton R. A. Lowden

1992-01-01

181

Gasoline Vapor Recovery  

NASA Technical Reports Server (NTRS)

Gasoline is volatile and some of it evaporates during storage, giving off hydrocarbon vapor. Formerly, the vapor was vented into the atmosphere but anti-pollution regulations have precluded that practice in many localities, so oil companies and storage terminals are installing systems to recover hydrocarbon vapor. Recovery provides an energy conservation bonus in that most of the vapor can be reconverted to gasoline. Two such recovery systems are shown in the accompanying photographs (mid-photo at right and in the foreground below). They are actually two models of the same system, although.configured differently because they are customized to users' needs. They were developed and are being manufactured by Edwards Engineering Corporation, Pompton Plains, New Jersey. NASA technological information proved useful in development of the equipment.

1979-01-01

182

Vapor Compression Distillation Module.  

National Technical Information Service (NTIS)

A Vapor Compression Distillation (VCD) module was developed and evaluated as part of a Space Station Prototype (SSP) environmental control and life support system. The VCD module includes the waste tankage, pumps, post-treatment cells, automatic controls ...

P. P. Nuccio

1975-01-01

183

Biofiltration of methanol vapor  

Microsoft Academic Search

Biofiltration of solvent and fuel vapors may offer a cost-effective way to comply with increasingly strict air emission standards. An important step in the development of this technology is to derive and validate mathematical models of the biofiltration process for predictive and scaleup calculations. For the study of methanol vapor biofiltration, an 8-membered bacterial consortium was obtained from methanol-exposed soil.

Zarook Shareefdeen; Basil C. Baltzis; Young-Sook Oh; Richard Bartha

1993-01-01

184

Comparative analysis of liquefied natural gas (LNG) and compressed natural gas (CNG) used by transit agencies in Texas. Research report  

Microsoft Academic Search

This study is a detailed comparative analysis of liquefied natural gas (LNG) and compressed natural gas (CNG). The study provides data on two alternative fuels used by transit agencies in Texas. First, we examine the `state-of-the- art` in alternative fuels to established a framework for the study. Efforts were made to examine selected characteristics of two types of natural gas

Lede

1997-01-01

185

Electric Power Generation and LNG Evaporation with the Aid of Gas Turbines within a Closed-Cycle Process.  

National Technical Information Service (NTIS)

LNG, after being pumped to customary pipeline pressure, has a high working potential which can be technically utilized. Thus, in a modern large-size terminal, a power potential in the order of magnitude of several hundred MW is available. In the course of...

D. Weber

1978-01-01

186

Worker Protection from Chemical Vapors: Hanford Tank Farms  

SciTech Connect

Chemical vapor emissions from underground hazardous waste storage tanks on the Hanford site in eastern Washington State are a potential concern because workers enter the tank farms on a regular basis for waste retrievals, equipment maintenance, and surveillance. Tank farm contractors are in the process of retrieving all remaining waste from aging single-shell tanks, some of which date to World War II, and transferring it to newer double-shell tanks. During the waste retrieval process, tank farm workers are potentially exposed to fugitive chemical vapors that can escape from tank head-spaces and other emission points. The tanks are known to hold more than 1,500 different species of chemicals, in addition to radionuclides. Exposure assessments have fully characterized the hazards from chemical vapors in half of the tank farms. Extensive sampling and analysis has been done to characterize the chemical properties of hazardous waste and to evaluate potential health hazards of vapors at the ground surface, where workers perform maintenance and waste transfer activities. Worker concerns, risk communication, and exposure assessment are discussed, including evaluation of the potential hazards of complex mixtures of chemical vapors. Concentrations of vapors above occupational exposure limits (OEL) were detected only at exhaust stacks and passive breather filter outlets. Beyond five feet from the sources, vapors disperse rapidly. No vapors have been measured above 50% of their OELs more than five feet from the source. Vapor controls are focused on limited hazard zones around sources. Further evaluations of vapors include analysis of routes of exposure and thorough analysis of nuisance odors. (authors)

Anderson, T.J. [CH2M HILL Hanford Group, Inc. / Environmental Health, Richland, WA (United States)

2007-07-01

187

Vapor core propulsion reactors  

NASA Technical Reports Server (NTRS)

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.

Diaz, Nils J.

1991-01-01

188

BTSC VAPOR INSTRUSION PRIMER "VAPOR INTRUSION CONSIDERATION FOR REDEVELOPMENT"  

EPA Science Inventory

This primer is designed for brownfields stakeholders concerned about vapor intrusion, including property owners, real estate developers, and contractors performing environmental site investigations. It provides an overview of the vapor intrusion issue and how it can impact the ap...

189

SPILLS: An Evaporation/Air Dispersion Model for Chemical Spills on Land.  

National Technical Information Service (NTIS)

SPILLS, an unsteady-state model representing the evaporation of a chemical spill and the atmospheric dispersion of the vapors is presented. The model estimates concentrations of the vapors as a function of time and distance downwind of instantaneously-for...

M. T. Fleischer R. P. Deschner R. M. Grimes

1982-01-01

190

Numerical study on mixing of sprayed liquid in an LNG storage tank  

NASA Technical Reports Server (NTRS)

This paper presents a numerical method to simulate the mixing of heavier LNG sprayed on lighter layer. Numerical results for evolutions of flow field and density field are obtained in a rectangular computational domain which includes the vicinity of the liquid surface. At the surface boundary, uniform distributions of the fluid velocity and the density are assumed. Detail structure of flow caused by impingements of liquid drops are neglected. But, to trigger a realistic motion, a series of random numbers is employed. It is used as an initial distribution of the density near the surface. This method successfully gives a realistic simulation of the mixing process. Numerical results for mixing velocity shows good agreement with experimental data.

Uchida, Hiroyuki; Arai, Tatsuya; Sugihara, Makoto; Nakayama, Mariko

1992-01-01

191

The dispersion theory of dispersion forces  

NASA Astrophysics Data System (ADS)

The long-range forces that act between neutral atoms and molecules have been known as dispersion forces since the work of London, who was the first to make manifest the connection between these forces and the dispersion of light by atoms, already guessed at by Newton. The analysis and application of the analyticity properties of scattering amplitudes, developed several decades ago in the context of quantum field theory, is known as dispersion theory. In this article we review the approach to dispersion forces based on dispersion theory. We give a general discussion of the concept of potential in quantum field theory and then show how a study of two-photon exchange amplitudes leads to a model-independent derivation and generalization of the formulas describing retarded dispersion forces for the case of two neutral atoms, first obtained by Casimir and Polder. We then review later extentions to the interaction of a charged and a neutral system and recent work on the case where both systems are charged. The connection between the dispersion-theory approach and more conventional methods is described. We also illustrate the use of dispersion-theory techniques to study forces arising from two-neutrino exchange and two-meson exchange. The effect of dispersion forces on the energy levels of the Rydberg states of hilium is briefly sketched. Finally, some open questions are mentioned.

Feinberg, G.; Sucher, J.; Au, C.-K.

1989-08-01

192

Enthalpy of Vaporization and Vapor Pressures: An Inexpensive Apparatus  

ERIC Educational Resources Information Center

A simple and inexpensive method to determine the enthalpy of vaporization of liquids by measuring vapor pressure as a function of temperature is described. The vapor pressures measured with the stopcock cell were higher than the literature values and those measured with the sidearm rubber septum cell were both higher and lower than literature…

Battino, Rubin; Dolson, David A.; Hall, Michael A.; Letcher, Trevor M.

2007-01-01

193

Graphite Fusion and Vaporization.  

National Technical Information Service (NTIS)

An analysis is conducted to establish the bounds of the carbon solid-liquidus-vapor phase diagram. Included in the analysis is an assessment of the graphite triple-point experiments. Results of the analysis indicate that the triple-point experimental data...

K. M. Kratsch

1969-01-01

194

Variable voltage portable vaporizer  

US Patent & Trademark Office Database

A portable vaporizer having an electronic control unit electrically coupled to a power source and an atomizer. The electronic control unit utilizes a voltage regulator which allows changes in an output voltage supplied to the atomizer in response to a change in electrical resistance of a potentiometer incorporated therewith.

2014-07-15

195

Water vapor lidar  

NASA Technical Reports Server (NTRS)

The feasibility was studied of measuring atmospheric water vapor by means of a tunable lidar operated from the space shuttle. The specific method evaluated was differential absorption, a two-color method in which the atmospheric path of interest is traversed by two laser pulses. Results are reported.

Ellingson, R.; Mcilrath, T.; Schwemmer, G.; Wilkerson, T. D.

1976-01-01

196

Water vapor diffusion membranes  

NASA Technical Reports Server (NTRS)

The program is reported, which was designed to define the membrane technology of the vapor diffusion water recovery process and to test this technology using commercially available or experimental membranes. One membrane was selected, on the basis of the defined technology, and was subjected to a 30-day demonstration trial.

Holland, F. F., Jr.; Smith, J. K.

1974-01-01

197

Vapor Grown Carbon Fiber/Polydicyclopentadiene Composites: Shapeable Pastes to Make Composite Tooling and Plasma Erosion-Resistant Parts.  

National Technical Information Service (NTIS)

Vapor grown carbon nanofibers (VGCF) with 60-250nm diameters and 10 to 80 micrometers lengths were blended with the nonpolar organic monomer, dicyclopentadiene, to create liquid dispersions or pastes (based on the wt% fiber used). Ruthenium catalysts were...

C. U. Pittman

2002-01-01

198

The dispersion theory of dispersion forces  

Microsoft Academic Search

The long-range forces that act between neutral atoms and molecules have been known as dispersion forces since the work of London, who was the first to make manifest the connection between these forces and the dispersion of light by atoms, already guessed at by Newton. The analysis and application of the analyticity properties of scattering amplitudes, developed several decades ago

G. Feinberg; J. Sucher; C.-K. Au

1989-01-01

199

The use of long acting subcutaneous levonorgestrel (LNG) gel depot as an effective contraceptive option for cotton-top tamarins (Saguinus oedipus).  

PubMed

Cotton-top tamarins (Saguinus oedipus) are a critically endangered species that have been bred successfully in captivity for many years. For two decades, the Cotton-top Tamarin SSP(©) has been challenged with a high rate of reproduction combined with a history of contraceptive failures and nonrecommended births using the current Depo Provera(®) (medroxyprogesterone acetate) injection followed by MGA (melengestrol acetate) implant contraception combination. To address these issues we have developed and tested the use of levonorgestrel (LNG) as an effective contraception option for cotton-top tamarins. LNG was delivered in an injectable, gel matrix consisting of polylactic-co-glycolic acid, triethyl citrate and N-methylpyrrolidone. This gel matrix forms a biodegradable depot at the subcutaneous injection site providing slow release of the active ingredient. Gel matrix composition and LNG concentration were adjusted in four gel formulations to maximize the duration of contraceptive efficacy while minimizing immediate post-injection increases in fecal LNG concentration. LNG treatment (68.44 ± 8.61 mg/kg) successfully eliminated ovarian cycles (fecal pregnanediol-3-glucuronide (PdG) and estrone conjugates (E(1) C)) for 198.8 ± 70.3 days (formulation four; range 19-50 weeks). It was demonstrated that subcutaneous LNG depot injection was an effective, reversible contraceptive option for the management of cotton-top tamarins in captivity. PMID:20938969

Wheaton, C J; Savage, A; Shukla, A; Neiffer, D; Qu, W; Sun, Y; Lasley, B L

2011-01-01

200

FEM3 Modeling of Ammonia and Hydrofluoric Acid Dispersion.  

National Technical Information Service (NTIS)

FEM3 is a three-dimensional computer model that was designed to simulate the atmospheric dispersion of heavier-than-air gas releases. Recently a phase-change submodel based on local thermodynamic equilibrium has been implemented to treat vapor-liquid tran...

D. N. Blewitt H. C. Rodean S. T. Chan

1987-01-01

201

Atmospheric Dispersion of Ammonia: An Ammonia Fog Model.  

National Technical Information Service (NTIS)

A simplification to the two-phase ammonia vapor-droplet fog problem has been implemented to study the dispersion of a spill of 40 tons of ammonia. We have circumvented the necessity of adding the partial differential equations for mass, momentum, and ener...

E. J. Kansa H. C. Rodean S. T. Chan D. L. Ermak

1983-01-01

202

Effects of the dispersion interaction in liquid water  

NASA Astrophysics Data System (ADS)

The properties of liquid water obtained from molecular simulations using a density functional theory (B3LYP) based force field [O. Akin-Ojo, F. Wang, J. Comput. Chem. 32 (2011) 453.] with and without an intermolecular dispersion interaction term are compared. Although it is small, the dispersion interaction is found to significantly affect some properties such as the density and the heat of vaporization but not others, for example, the atom-atom radial distribution functions and the infrared spectra. The inclusion of the dispersion interaction in the force field produces an increase in the computed self diffusivity comparable to that resulting from a ˜5 K rise in temperature.

Akin-Ojo, Omololu; Wang, Feng

2011-09-01

203

Adsorption of vapors of argon, nitrogen, n-hexane, and benzene on boron nitride and molybdenum sulfide  

Microsoft Academic Search

1.The values of the adsorption of argon vapor per unit surface of adsorbents of different kinds differ sharply, since in this case only electrokinetic (dispersion) interactions are manifested, which depend basically upon the concentration, dimensions, and polarizability of the atoms on the surface of the adsorbent. The values of the adsorption of nitrogen vapor on adsorbents of different kinds are

L. D. Belyakova; A. V. Kiselev

1966-01-01

204

Visual Observation of Vapor Film Collapse Behavior During Vapor Explosion  

SciTech Connect

During severe accident of a light water reactor, various thermal hydraulic phenomena including vapor explosion could threaten the integrity of the containment vessel. Thermal detonation model is proposed to describe the vapor explosion. According to the model, several processes should be sequentially satisfied for the trigger phenomena of the vapor explosion. One of the most important processes for the trigger phenomena is the vapor film collapse around high temperature molten material droplets. In the present study, the vapor film collapse behavior around high temperature solid particle submerged into water was experimentally investigated by attacking a pressure pulse to the vapor film on a high temperature sold particle. The interfacial phenomena between vapor and water were measure by using a high-speed video camera of the maximum speed of 40,500 fps. The visual data obtained were processed with visual data processing techniques. That is, the average vapor film thickness was estimated, dynamic behaviors of the interfaces were analyzed with PIV technique and the interface movement was estimated with the digital auto correlation techniques from the visual data obtained. Furthermore, the transients of the temperature and pressure were simultaneously measured. The interfacial temperatures between vapor and water, and between molted liquid and water are analytically estimated by solving the heat conduction equation with the data obtained as the boundary conditions. It is clarified that vapor collapse by pressure pulse occurs homogeneously around the vapor film surface on a high temperature particle. Microscopic information are obtained from the visual data by using visual data processing technique, PIV technique and digital auto-correlation technique. At the time the vapor film surface changes to white, the saturation temperature exceeds the interfacial temperature. The microscopic vapor film collapse behavior indicates the possibility of the phase change at the vapor film collapse. (authors)

Yutaka Abe; Hideki Nariai [University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)

2002-07-01

205

Stratified vapor generator  

DOEpatents

A stratified vapor generator (110) comprises a first heating section (H.sub.1) and a second heating section (H.sub.2). The first and second heating sections (H.sub.1, H.sub.2) are arranged so that the inlet of the second heating section (H.sub.2) is operatively associated with the outlet of the first heating section (H.sub.1). A moisture separator (126) having a vapor outlet (164) and a liquid outlet (144) is operatively associated with the outlet (124) of the second heating section (H.sub.2). A cooling section (C.sub.1) is operatively associated with the liquid outlet (144) of the moisture separator (126) and includes an outlet that is operatively associated with the inlet of the second heating section (H.sub.2).

Bharathan, Desikan (Lakewood, CO) [Lakewood, CO; Hassani, Vahab (Golden, CO) [Golden, CO

2008-05-20

206

Chemical vapor deposition growth  

NASA Technical Reports Server (NTRS)

A chemical vapor deposition (CVD) reactor system with a vertical deposition chamber was used for the growth of Si films on glass, glass-ceramic, and polycrystalline ceramic substrates. Silicon vapor was produced by pyrolysis of SiH4 in a H2 or He carrier gas. Preliminary deposition experiments with two of the available glasses were not encouraging. Moderately encouraging results, however, were obtained with fired polycrystalline alumina substrates, which were used for Si deposition at temperatures above 1,000 C. The surfaces of both the substrates and the films were characterized by X-ray diffraction, reflection electron diffraction, scanning electron microscopy optical microscopy, and surface profilometric techniques. Several experiments were conducted to establish baseline performance data for the reactor system, including temperature distributions on the sample pedestal, effects of carrier gas flow rate on temperature and film thickness, and Si film growth rate as a function of temperature.

Ruth, R. P.; Manasevit, H. M.; Kenty, J. L.; Moudy, L. A.; Simpson, W. I.; Yang, J. J.

1976-01-01

207

Field tests on human tolerance to (LNG) fire radiant heat exposure, and attenuation effects of clothing and other objects  

Microsoft Academic Search

A series of field tests exposing mannequins clothed with civilian clothing to a 3m×3m square liquefied natural gas (LNG) pool fire was conducted. Both single layer clothing and double layer clothing were used. The radiant heat flux incident outside the clothing and incident on the skin covered by clothing were measured using wide-angle radiometers, for durations of 100–200s (per test).

Phani K. Raj

2008-01-01

208

Chemical vapor infiltration  

SciTech Connect

Continuous filament ceramic composites are enabling new, high temperature structural applications. Chemical vapor infiltration methods for producing these composites are being studied, with the complexity of filament weaves and deposition chemistry merged with standard heat and mass transport relationships. Silicon carbide-based materials are, by far, the most advanced, and are already being used in aerospace applications. This paper will address the state-of-the-art of the technology and outline current issues.

Besmann, T.M.; Stinton, D.P.; Lowden, R.A.

1992-01-01

209

Chemical vapor infiltration  

SciTech Connect

Continuous filament ceramic composites are enabling new, high temperature structural applications. Chemical vapor infiltration methods for producing these composites are being studied, with the complexity of filament weaves and deposition chemistry merged with standard heat and mass transport relationships. Silicon carbide-based materials are, by far, the most advanced, and are already being used in aerospace applications. This paper will address the state-of-the-art of the technology and outline current issues.

Besmann, T.M.; Stinton, D.P.; Lowden, R.A.

1992-02-01

210

FIELD DISPERSANT EFFECTIVENESS TEST  

EPA Science Inventory

The EPA's OHMSETT facility has developed a rapid field test that includes some of the theoretical aspects and conditions of dispersion at sea. This Field Dispersant Effectiveness Test (FDET) has been used to evaluate the dispersibility of various commonly-transported oils and mak...

211

Dispersion in the Surfzone: Tracer Dispersion Studies.  

National Technical Information Service (NTIS)

Terrestrial runoff and river input dominates urban pollutant loading rates degrading nearshore and surfzone water quality (e.g., Boehm et al., 2002). Surfzone mixing processes disperse and dilute such (and other types of) pollution. On smaller length-scal...

F. Feddersen

2011-01-01

212

?-Propiolactone Vapor Decontamination  

PubMed Central

Although ?-propiolactone (BPL) is an effective vapor-phase decontaminant for enclosed areas, some problems have been encountered in its use. Adequate air circulation during BPL dissemination could eliminate most of these problems. It is recommended that, when decontaminating the ordinary building or laboratory, the amount of BPL sprayed be changed from the previously suggested 1 gal/16,000 cubic ft of space to 1 gal/25,000 cubic ft. The use of aqueous BPL solutions and thermal-type generators is not recommended.

Hoffman, Robert K.; Buchanan, Lee M.; Spiner, David R.

1966-01-01

213

Vapor Diffusion Apparatus  

NASA Technical Reports Server (NTRS)

Vapor Diffusion Apparatus (VDA-2) was developed by the University of Alabama in Birmingham for NASA's Marshall Space Flight Center. In the original VDA, a protein solution and a precipitant are extruded by two plungers onto the tip of a small syringe and allowed to evaporate, raising the concentration and prompting protein molecules to crystallize. In the VDA-2 version, a third plunger was added to mix the two solutions before returning the mix to the syringe tip. The principal investigator is Dr. Larry Delucas of the University of Alabama in Birmingham.

2001-01-01

214

Vapor Diffusion Apparatus  

NASA Technical Reports Server (NTRS)

Vapor Diffusion Apparatus (VDA and VDA-2) was developed by the University of Alabama in Birmingham for NASA's Marshall Space Flight Center. In the original VDA, a protein solution and a precipitant are extruded by two plungers onto the tip of a small syringe and allowed to evaporate, raising the concentration and prompting protein molecules to crystallize. In the VDA-2 version, a third plunger was added to mix the two solutions before returning the mix to the syringe tip. The principal investigator is Dr. Larry Delucas of the University of Alabama in Birmingham

2001-01-01

215

Vapor-Liquid Equilibria for Some Concentrated Aqueous PolymerSolutions  

SciTech Connect

Vapor-liquid-equilibrium data were obtained for binary aqueous solutions of six water-soluble linear polymers in the range 70-95 C. A classical gravimetric sorption method was used to measure the amount of solvent absorbed as a function of vapor-phase water pressure. Polymers studied were polyvinylpyrrolidone, polyethyleneoxide, polyvinylalcohol, hydroxyethylcellulose, polyethylenimine, polymethylvinylether. The experimental data were reduced with Hino's lattice model that distinguished the interactions due to London dispersion forces and those due to hydrogen bonding.

Striolo, Alberto; Prausnitz, John M.

1999-07-01

216

Meals, quarters for 8,200 needed at peak in LNG project  

SciTech Connect

It has everything a real town has except women, children, schools, bars, and old people. It is the huge camp built at Ras Laffan, Qatar, on the shores of the Persian Gulf to lodge and feed over 5,000 workers as they build the first plant in the emirate for liquefying millions of tons of natural gas yearly. Japan`s Chiyoda Corp. is the top contractor for the Qatar Liquefied Gas Co. (QatarGas) project, which is owned by a Qatari, French, American, and Japanese consortium. As part of the plant construction contract, Chiyoda built the camp, which Teyseer Services Co., the Qatar affiliate of the French company, Sodexho Alliance, now runs and maintains. Sodexho is the world`s largest catering/remote site management organization. It has had all its expertise in those fields put to the test for nearly 4 years supporting this world-scale LNG project which will be completed this summer. This project is described.

Aalund, L.R.

1998-04-27

217

LNG (liquefied natural gas) as a fuel and refrigerant for diesel powered shrimp boats  

SciTech Connect

A 3406-B Caterpillar and a 4.236 Perkins have been converted from their standard diesel configuration to dual-fuel engines. These engines operate using an aspirated charge of natural gas and a pilot charge of diesel fuel. The pilot is injected for combustion initiation, performing the same task as a spark plug in a spark ignition engine. Natural gas supplies 80% of the total heat addition at full load for both engines. The diesel fuel provides ignition, performs the function of idling the engine, and acts as a coolant for the injector tips. The diesel pilot setting remains constant throughout the operating range and provides a regular repeatable idle for the engine during no-load operation. A shrimp boat is being used to evaluate the dual-fuel system. The vessel normally carries 16000 1 of diesel fuel giving it a trip length of 14-21 days. To operate on natural gas with similar trip length requires liquification and cryogenic storage at -163/sup 0/C. This type of storage provides the necessary energy density needed for on board fuel storage. A 22 m shrimp boat will carry approximately 17000 1 of LNG in insulated tanks. Urethane insulation is used as both an insulator against heat leak and as a partial tank support structure.

Acker, G. Jr.; Brett, C.E.; Schaetzle, W.J.; Song, Y.K.

1988-01-01

218

Water Vapor Circulation on Earth  

NSDL National Science Digital Library

Water vapor plays an important role in the water cycle and in the distribution of heat around the planet. By observing the movement of water vapor, scientists can study global wind patterns and the development of cyclonic storms. This simulation from the National Center for Atmospheric Research shows the circulation of water vapor around the Earth over the course of a year. The segment is four minutes fifty-two seconds in length. Quicktime is required to view the clip.

2010-08-27

219

Dispersible carbon nanotubes.  

PubMed

A method is proposed to produce nanoparticles dispersible and recyclable in any class of solvents, and the concept is illustrated with the carbon nanotubes. Classically, dispersions of CNTs can be achieved through steric stabilization induced by adsorbed or grafted polymer chains. Yet, the surface modification of CNTs surfaces is irreversible, and the chemical nature of the polymer chains imposes the range of solvents in which CNTs can be dispersed. To address this limitation, supramolecular bonds can be used to attach and to detach polymer chains from the surface of CNTs. The reversibility of supramolecular bonds offers an easy way to recycle CNTs as well as the possibility to disperse the same functional CNTs in any type of solvent, by simply adapting the chemical nature of the stabilizing chains to the dispersing medium. The concept of supramolecular functionalization can be applied to other particles, for example, silica or metal oxides, as well as to dispersing in polymer melts, films or coatings. PMID:24458908

Soulié-Ziakovic, Corinne; Nicolaÿ, Renaud; Prevoteau, Alexandre; Leibler, Ludwik

2014-01-27

220

A Planar-Fluorescence Imaging Technique for Studying Droplet-Turbulence Interactions in Vaporizing Sprays  

NASA Technical Reports Server (NTRS)

Droplet turbulence interactions directly affect the vaporization and dispersion of droplets in liquid sprays and therefore play a major role in fuel oxidizer mixing in liquid fueled combustion systems. Proper characterization of droplet turbulence interactions in vaporizing sprays require measurement of droplet size velocity and size temperature correlations. A planar, fluorescence imaging technique is described which is being developed for simultaneously measuring the size, velocity, and temperature of individual droplets in vaporizing sprays. Preliminary droplet size velocity correlation measurements made with this technique are presented. These measurements are also compared to and show very good agreement with measurements made in the same spray using a phase Doppler particle analyzer.

Santavicca, Dom A.; Coy, E.

1990-01-01

221

33 CFR 154.828 - Vapor recovery and vapor destruction units.  

Code of Federal Regulations, 2013 CFR

...Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Vapor recovery and vapor destruction units...Navigation and Navigable Waters COAST GUARD, DEPARTMENT...Systems § 154.828 Vapor recovery and vapor destruction...

2013-07-01

222

Modeling of near and supercritical droplet vaporization  

SciTech Connect

The model considers the case when a droplet, initially at ambient or elevated temperature, is suddenly injected into a gaseous environment that is at a temperature that is well above, and at a pressure that is slightly below (near-critical), or well above (super-critical) those corresponding to the critical value of the liquid. First, an analysis is developed of the diffusionally controlled evaporation of a fuel droplet at near and super-critical conditions. The transient conservation equations for the gas and liquid phases are solved using an expansion solution in a power series in time. The series expansion solution provides an explicit expression for the interface regression, the transient heat diffusion in the liquid and gas phases, and the mass transfer in the gas phase. An analysis of the super-critical, convective, evaporation of a fuel droplet in a stagnant point flow is developed next. The present analysis describes the transient evaporation of a liquid fuel at its stagnation point in a high temperature, high pressure, environment. The transient conservation equations for both liquid and gas phases are solved simultaneously to determine the profiles of the vorticity, temperature and species distributions, and the regression velocity of the liquid-gas interface. A third model is developed of the dispersion of a vapor fuel droplet that is suddenly set in motion in a gaseous environment that has a density similar to that of the fuel vapor. In the analysis, the transient, axisymmetric, stream function-vorticity and species equations are solved to determine the evolution of the vorticity distribution, species mixing and the distortion of the initial interface. The results show that the initially spherical gaseous fuel droplet is extensively distorted, adopting a mushroom-like shape, and also the vapor mixing process is greatly enhanced around the vortex ring.

Lee, H.

1987-01-01

223

Thermal Plasma Chemical Vapor Deposition  

Microsoft Academic Search

Diamond has many unrivaled properties and has great application potentials in modern industry. Among various metastable chemical vapor deposition methods for producing diamond, thermal plasma chemical vapor deposition has shown advantages of offering high growth rates and high quality. However, systematic parametric studies are needed for optimization of the process. This study investigates the effects of substrate materials, substrate temperatures,

Zhipeng Lu

1991-01-01

224

Chemical vapor deposition growth  

NASA Technical Reports Server (NTRS)

The chemical vapor deposition (CVD) method for the growth of Si sheet on inexpensive substrate materials is investigated. The objective is to develop CVD techniques for producing large areas of Si sheet on inexpensive substrate materials, with sheet properties suitable for fabricating solar cells meeting the technical goals of the Low Cost Silicon Solar Array Project. Specific areas covered include: (1) modification and test of existing CVD reactor system; (2) identification and/or development of suitable inexpensive substrate materials; (3) experimental investigation of CVD process parameters using various candidate substrate materials; (4) preparation of Si sheet samples for various special studies, including solar cell fabrication; (5) evaluation of the properties of the Si sheet material produced by the CVD process; and (6) fabrication and evaluation of experimental solar cell structures, using standard and near-standard processing techniques.

Ruth, R. P.; Manasevit, H. M.; Kenty, J. L.; Moudy, L. A.; Simpson, W. I.; Yang, J. J.

1976-01-01

225

Particle Transport by Rapid Vaporization of Superheated Liquid.  

NASA Astrophysics Data System (ADS)

Superheated liquid vaporizing explosively in a particle bed inside a cylindrical test cell has been studied using a rapid depressurization apparatus. The experiments provide insights into the explosive vaporization phenomenon and the multiphase flow which is generated by the rapid production of vapor. Inside the sealed test cell, spherical glass particles are immersed in a volatile liquid, Refrigerant 12 or 114 at 300K. When the diaphragm at the upper end of the test cell is ruptured, the liquid pressure is reduced to a predetermined pressure within milliseconds. Since the liquid temperature is higher than the boiling temperature at reduced pressure, the liquid achieves a superheated state and nucleate boiling begins among the particles. The particle-liquid-vapor flow produced by the rapid release of vapor has been found to differ depending on whether the pressure is reduced below a critical level, which is 55% of the vapor pressure in the experiments conducted. When the final pressure is greater than critical, vapor pockets continue to grow throughout the particle bed and displace a liquid-particles mixture out from the test cell. When the final pressure is below critical, the particles are dispersed by a wave -like phenomenon (disruption front) where explosive vaporization appears to be localized in a narrow region. A disruption front in R12 travels at about 380 cm/s, and at about 200 cm/s in R114. Experiments have been performed at various conditions to study the vaporization and transport process. High -speed cinematography and fast-response pressure gauges have provided data on the particle acceleration process. The inertial effect on particle acceleration has been studied by conducting similar experiments in a centrifuge. Using this data, the transport process associated with the disruption front has been examined in detail. An empirical relationship between the particle weight and viscous drag is presented for this particular case. This study concludes with discussions based on analytical models of the disruption front to approximate flows properties which are intractable experimentally. It is suggested that a disruption front is an expansion process which maximizes vaporization and entropy.

Sugioka, Ichiro

226

Particle transport by rapid vaporization of superheated liquid  

NASA Astrophysics Data System (ADS)

Superheated liquid vaporizing explosively in a particle bed inside a cylindrical test cell has been studied using a rapid depressurization apparatus. The experiments provide insights into the explosive vaporization phenomenon and the multiphase flow which is generated by the rapid production of vapor.Inside the sealed test cell, spherical glass particles are immersed in a volatile liquid, Refrigerant 12 or 114 at 300K. When the diaphragm at the upper end of the test cell is ruptured, the liquid pressure is reduced to a predetermined pressure within milliseconds. Since the liquid temperature is higher than the boiling temperature at reduced pressure, the liquid achieves a superheated state and nucleate boiling begins among the particles. The particle-liquid-vapor flow produced by the rapid release of vapor has been found to differ depending on whether the pressure is reduced below a critical level, which is 55% of the vapor pressure in the experiments conducted. When the final pressure is greater than critical, vapor pockets continue to grow throughout the particle bed and displace a liquid-particles mixture out from the test cell. When the final pressure is below critical, the particles are dispersed by a wave-like phenomenon (disruption front) where explosive vaporization appears to be localized in a narrow region. A disruption front in R12 travels at about 380 cm/s, and at about 200 cm/s in R114.Experiments have been performed at various conditions to study the vaporization and transport process. High-speed cinematography and fast response pressure gauges have provided data on the particle acceleration process. The inertial effect on particle acceleration has been studied by conducting similar experiments in a centrifuge. Using this data, the transport process associated with the disruption front has been examined in detail. An empirical relationship between the particle weight and viscous drag is presented for this particular case. This study concludes with discussions based on analytical models of the disruption front to approximate flows properties which are intractable experimentally. It is suggested that a disruption front is an expansion process which maximizes vaporization and entropy.

Sugioka, Ichiro

227

Constrained Vapor Bubble  

NASA Technical Reports Server (NTRS)

The nonisothermal Constrained Vapor Bubble, CVB, is being studied to enhance the understanding of passive systems controlled by interfacial phenomena. The study is multifaceted: 1) it is a basic scientific study in interfacial phenomena, fluid physics and thermodynamics; 2) it is a basic study in thermal transport; and 3) it is a study of a heat exchanger. The research is synergistic in that CVB research requires a microgravity environment and the space program needs thermal control systems like the CVB. Ground based studies are being done as a precursor to flight experiment. The results demonstrate that experimental techniques for the direct measurement of the fundamental operating parameters (temperature, pressure, and interfacial curvature fields) have been developed. Fluid flow and change-of-phase heat transfer are a function of the temperature field and the vapor bubble shape, which can be measured using an Image Analyzing Interferometer. The CVB for a microgravity environment, has various thin film regions that are of both basic and applied interest. Generically, a CVB is formed by underfilling an evacuated enclosure with a liquid. Classification depends on shape and Bond number. The specific CVB discussed herein was formed in a fused silica cell with inside dimensions of 3x3x40 mm and, therefore, can be viewed as a large version of a micro heat pipe. Since the dimensions are relatively large for a passive system, most of the liquid flow occurs under a small capillary pressure difference. Therefore, we can classify the discussed system as a low capillary pressure system. The studies discussed herein were done in a 1-g environment (Bond Number = 3.6) to obtain experience to design a microgravity experiment for a future NASA flight where low capillary pressure systems should prove more useful. The flight experiment is tentatively scheduled for the year 2000. The SCR was passed on September 16, 1997. The RDR is tentatively scheduled for October, 1998.

Huang, J.; Karthikeyan, M.; Plawsky, J.; Wayner, P. C., Jr.

1999-01-01

228

Dispersion strengthened copper  

DOEpatents

A composition of matter is described which is comprised of copper and particles which are dispersed throughout the copper, where the particles are comprised of copper oxide and copper having a coating of copper oxide. A method for making this composition of matter is also described. This invention relates to the art of powder metallurgy and, more particularly, it relates to dispersion strengthened metals.

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

1990-01-09

229

Dispersal of forest insects  

NASA Technical Reports Server (NTRS)

Dispersal flights of selected species of forest insects which are associated with periodic outbreaks of pests that occur over large contiguous forested areas are discussed. Gypsy moths, spruce budworms, and forest tent caterpillars were studied for their massive migrations in forested areas. Results indicate that large dispersals into forested areas are due to the females, except in the case of the gypsy moth.

Mcmanus, M. L.

1979-01-01

230

A Column Dispersion Experiment.  

ERIC Educational Resources Information Center

Crushed glass and a Rhodamine B solution are used in a one-dimensional optically scanned column experiment to study the dispersion phenomenon in porous media. Results indicate that the described model gave satisfactory results and that the dispersion process in this experiment is basically convective. (DC)

Corapcioglu, M. Y.; Koroglu, F.

1982-01-01

231

Spores Disperse, Too!  

ERIC Educational Resources Information Center

Suggests the use of spores and spore-producing structures to show adaptations facilitating spore dispersal and dispersal to favorable environments. Describes several activities using horsetails, ferns, and mosses. Lists five safety factors related to use of mold spores in the classroom. (DS)

Schumann, Donna N.

1981-01-01

232

Dispersion Forces and Duality  

Microsoft Academic Search

We formulate a symmetry principle on the basis of the duality of electric and magnetic fields and apply it to dispersion forces. Within the context of macroscopic quantum electrodynamics, we rigorously establish duality invariance for the free electromagnetic field in the presence of causal magnetoelectrics. Dispersion forces are given in terms of the Green tensor for the electromagnetic field and

Stefan Yoshi Buhmann; Stefan Scheel; Hassan Safari; Dirk-Gunnar Welsch

2009-01-01

233

Dispersion-managed solitons at normal average dispersion  

Microsoft Academic Search

We find that in a dispersion-managed fiber, in which the strength of the dispersion management is above some threshold, solitons can exist with normal average dispersion. When the normal average dispersion is below some limiting value there exist two soliton solutions with the same pulse duration and different pulse energies. When the normal average dispersion is above this limiting value,

V. S. Grigoryan; C. R. Menyuk

1998-01-01

234

Tested Demonstrations. Gasoline Vapor: An Invisible Pollutant  

ERIC Educational Resources Information Center

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)

Stephens, Edgar R.

1977-01-01

235

Cross Disperser Mode Test  

NASA Astrophysics Data System (ADS)

This program is to test the scientific capabilities and some of the implementation procedures of the STIS cross-disperser modes. The sensitivity of the cross-disperser modes in a few settings will be determined using a standard star. Slit throughputs of the orthogonal slits will also be determined using different slits. The results would be useful in determining the limiting magnitudes {for a given S/N and exposure time} for different cross-disperser modes. One of the main rationale behind making these cross-disperser modes not available in cycle 7 was the fact that the NUV and FUV MAMA detectors are positioned such that the light in the cross-disperser modes falls in both NUV and FUV-MAMA detectors simultaneously. Thus the BOP checking procedure was complicated. Now that the MAMA detectors can be switched off at any given time, that is less of a constraint. However, it will be necessary to restrict the use of the cross-disperser modes to one detector at a time. Therefore to implement their use, the ground s ystem would have to be modified to allow the use of only one MAMA per visit when the cross-dispersers are used and shut off the other MAMA. For this proposal, however, both MAMAs can be kept on. The target is chosen such that there is no overlight if both detectors are on at the same time.

Sahu, Kailash

1997-12-01

236

Passive vapor extraction feasibility study  

SciTech Connect

Demonstration of a passive vapor extraction remediation system is planned for sites in the 200 West Area used in the past for the disposal of waste liquids containing carbon tetrachloride. The passive vapor extraction units will consist of a 4-in.-diameter pipe, a check valve, a canister filled with granular activated carbon, and a wind turbine. The check valve will prevent inflow of air that otherwise would dilute the soil gas and make its subsequent extraction less efficient. The granular activated carbon is used to adsorb the carbon tetrachloride from the air. The wind turbine enhances extraction rates on windy days. Passive vapor extraction units will be designed and operated to meet all applicable or relevant and appropriate requirements. Based on a cost analysis, passive vapor extraction was found to be a cost-effective method for remediation of soils containing lower concentrations of volatile contaminants. Passive vapor extraction used on wells that average 10-stdft{sup 3}/min air flow rates was found to be more cost effective than active vapor extraction for concentrations below 500 parts per million by volume (ppm) of carbon tetrachloride. For wells that average 5-stdft{sup 3}/min air flow rates, passive vapor extraction is more cost effective below 100 ppm.

Rohay, V.J.

1994-06-30

237

MODIFICATION OF SPILL FACTORS AFFECTING AIR POLLUTION. VOLUME I. AN EVALUATION OF COOLING AS A VAPOR MITIGATION PROCEDURE FOR SPILLED VOLATILE CHEMICALS  

EPA Science Inventory

Spilled chemicals that pose a hazard to the land and water ecosystems can also provide a significant vapor hazard. Although the vapors released by such chemicals may ultimately be dispersed in the environment with little long-term effects, they do pose a hazard to life and proper...

238

Vaporization of lithium sulfide  

NASA Astrophysics Data System (ADS)

The vaporization of lithium sulfide has been studied by the mass spectrometric Knudsen effusion method. Over the temperature range from 1257 to 1441 K the partial pressures of Li(g), S(g), LiS(g), Li 2S(g) and S 2(g) are found to be log pLi = (9.66 ± 0.31) - (1.614 ± 0.040) 10 4/ T, logpS = (10.84 ± 0.45) - (2.117 ± 0.065) 10 4/ T, logpLiS = (10.15 ± 0.11) -(2.079 ± 0.014) 10 4/ T, logpLi2S = (10.41 ± 0.13) - (1.978 ± 0.018) 10 4/ T and logpS2 = (11.08 ± 0.36) - (2.056 ± 0.052) 10 4/ T, where the unit of pressures is pascal. From the enthalpies of reaction for the gaseous equilibria, the enthalpies of formation and the atomization energies for LiS(g) and Li 2S(g) have been determined to be ?Hf298 o( LiS, g) = (127.4 ± 7.8) kJ/ mol, ?Hf298 o( Li2S, g) = (-49.3 ± 9.6) kJ/ mol, D0o( LiS) = (308.8 ± 7.6) kJ/ mol and D0o( Li2S) = (644.3 ± 9.1) kJ/ mol, respectively.

Kimura, Hitoshi; Asano, Mitsuru; Kubo, Kenji

1981-04-01

239

Archimedes Mass Filter Vaporizer  

NASA Astrophysics Data System (ADS)

Archimedes Technology Group, Inc., is developing a plasma mass separator called the Archimedes Filter that separates waste oxide mixtures ion by ion into two mass groups: light and heavy. Since high-level waste at Hanford has 99.9its radioactivity associated with heavy elements, the Archimedes Filter can effectively decontaminate over three-quarters of that waste. The Filter process involves some preprocessing followed by volatilization and separation by the magnetic and electric fields of the main plasma. This presentation describes the approach to volatilization of the waste oxy-hydroxide mixture by means of a very high heat flux (q > 10 MW/m2). Such a high heat flux is required to ensure congruent evaporation of the complex oxy-hydroxide mixture and is achieved by injection of small droplets of molten waste into an inductively coupled plasma (ICP) torch. This presentation further addresses different issues related to evaporation of the waste including modeling of droplet evaporation, estimates of parameters of plasma torch, and 2D modeling of the plasma. The experimental test bed for oxide vaporization and results of the initial experiments on oxide evaporation in 60 kW ICP torch will also be described.

Putvinski, S.; Agnew, A. F.; Cluggish, B. P.; Ohkawa, T.; Sevier, L.; Umstadter, K. R.; Dresvin, S. V.; Kuteev, B. V.; Feygenson, O. N.; Ivanov, D. V.; Zverev, S. G.; Miroshnikov, I. V.; Egorov, S. M.; Kiesewetter, D. V.; Maliugin, V. I.

2001-10-01

240

Chemical vapor deposition growth  

NASA Technical Reports Server (NTRS)

The objective was to investigate and develop chemical vapor deposition (CVD) techniques for the growth of large areas of Si sheet on inexpensive substrate materials, with resulting sheet properties suitable for fabricating solar cells that would meet the technical goals of the Low Cost Silicon Solar Array Project. The program involved six main technical tasks: (1) modification and test of an existing vertical-chamber CVD reactor system; (2) identification and/or development of suitable inexpensive substrate materials; (3) experimental investigation of CVD process parameters using various candidate substrate materials; (4) preparation of Si sheet samples for various special studies, including solar cell fabrication; (5) evaluation of the properties of the Si sheet material produced by the CVD process; and (6) fabrication and evaluation of experimental solar cell structures, using impurity diffusion and other standard and near-standard processing techniques supplemented late in the program by the in situ CVD growth of n(+)/p/p(+) sheet structures subsequently processed into experimental cells.

Ruth, R. P.; Manasevit, H. M.; Campbell, A. G.; Johnson, R. E.; Kenty, J. L.; Moudy, L. A.; Shaw, G. L.; Simpson, W. I.; Yang, J. J.

1978-01-01

241

Aqueous silicone dispersion  

US Patent & Trademark Office Database

The invention concerns a silicon dispersion hardenable by cross-linking and useable particularly as putty, paint or film coating. The dispersion according to the instant invention contains hydroxylated condensable constituents and is free from hydrolyzable substituents capable of being transformed into volatile organic compounds, is free from volatile organic compounds and polyvinil alcohol, and contains an .alpha.,.omega.-diOH polyorganosiloxane (A), an adherence promoter (B) with NH.sub.2 functions and OH functions, and, optionally, a catalyst (C), a surfactant (D), a cross-linking agent (E), fillers (F), a dispersing agent (G), a plasticizer (H), an antifungal agent (I), an antifoaming agent (J), a stabilizer (K) or a base (L). The invention is useful for putty or film coatings prepared with this dispersion.

2003-02-18

242

Naturally occurring vapor-liquid-solid (VLS) Whisker growth of germanium sulfide  

USGS Publications Warehouse

The first naturally occurring terrestrial example of vapor-liquid-solid (VLS) growth has been observed in condensates from gases released by burning coal in culm banks. Scanning electron microscopy, X-ray diffraction, and energy dispersive analysis indicate that the crystals consist of elongated rods (??? 100 ??m) of germanium sulfide capped by bulbs depleted in germanium. ?? 1974.

Finkelman, R. B.; Larson, R. R.; Dwornik, E. J.

1974-01-01

243

Nanocrystal dispersed amorphous alloys  

NASA Technical Reports Server (NTRS)

Compositions and methods for obtaining nanocrystal dispersed amorphous alloys are described. A composition includes an amorphous matrix forming element (e.g., Al or Fe); at least one transition metal element; and at least one crystallizing agent that is insoluble in the resulting amorphous matrix. During devitrification, the crystallizing agent causes the formation of a high density nanocrystal dispersion. The compositions and methods provide advantages in that materials with superior properties are provided.

Perepezko, John H. (Inventor); Allen, Donald R. (Inventor); Foley, James C. (Inventor)

2001-01-01

244

Dispersion management with filtering.  

PubMed

We present analytical and numerical results for dispersion-managed solitons in a fiber link including guiding filters and compensating gain, both taken in the distributed approximation. Stationary propagation regimes with anomalous, zero, and normal path-average dispersion (PAD) are identified. New features, compared with those of the case without filters, are the absence of a critical strength for propagation at zero and normal PAD and, instead, the existence of a critical power for stationary propagation at any PAD. PMID:18071554

Berntson, A; Malomed, B A

1999-04-15

245

Overview of chemical vapor infiltration.  

National Technical Information Service (NTIS)

chemical vapor infiltration (CVI) is developing into a commercially important method for the fabrication of continuous filament ceramic composites. Current efforts are focused on the development of an improved understanding of the various processes in CVI...

T. M. Besmann D. P. Stinton R. A. Lowden

1993-01-01

246

Modeling of Chemical Vapor Infiltration.  

National Technical Information Service (NTIS)

Ceramic matrix composites can be fabricated by chemical vapor infiltration (CVI) of a fibrous preform. In conventional processing, the reactant gases diffuse into the preform under isothermal conditions, depositing material onto the fibers and forming a c...

T. L. Starr

1989-01-01

247

Microwave assisted chemical vapor infiltration.  

National Technical Information Service (NTIS)

A microwave assisted process for production of continuous fiber reinforced ceramic matrix composites is described. A simple apparatus combining a chemical vapor infiltration reactor with a conventional 700 W multimode oven is described. Microwave induced ...

D. J. Devlin R. P. Currier R. S. Barbero B. F. Espinoza N. Elliott

1991-01-01

248

Water vapor diffusion membranes, 2  

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

249

Vapor sampling and analysis plan.  

National Technical Information Service (NTIS)

This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, Oak Ridge National Laboratory, and PNL tank vapor program. The scope of this plan is to provide guidance for the sampling and anal...

C. S. Homi

1995-01-01

250

Portable vapor diffusion coefficient meter  

DOEpatents

An apparatus for measuring the effective vapor diffusion coefficient of a test vapor diffusing through a sample of porous media contained within a test chamber. A chemical sensor measures the time-varying concentration of vapor that has diffused a known distance through the porous media. A data processor contained within the apparatus compares the measured sensor data with analytical predictions of the response curve based on the transient diffusion equation using Fick's Law, iterating on the choice of an effective vapor diffusion coefficient until the difference between the predicted and measured curves is minimized. Optionally, a purge fluid can forced through the porous media, permitting the apparatus to also measure a gas-phase permeability. The apparatus can be made lightweight, self-powered, and portable for use in the field.

Ho, Clifford K. (Albuquerque, NM)

2007-06-12

251

Water Vapor Circulation on Earth  

NSDL National Science Digital Library

This simulation from the National Center for Atmospheric Research portrays annual patterns in water vapor and precipitation across the globe, illustrating general circulation patterns as well as seasonal and regional variation.

Foundation, Wgbh E.

2005-10-21

252

A stratospheric water vapor feedback  

NASA Astrophysics Data System (ADS)

Variations in stratospheric water vapor play a role in the evolution of our climate. We show here that variations in water vapor since 2004 can be traced to tropical tropopause layer (TTL) temperature perturbations from at least three processes: the quasi-biennial oscillation, the strength of the Brewer-Dobson circulation, and the temperature of the troposphere. The connection between stratospheric water vapor and the temperature of the troposphere implies the existence of a stratospheric water vapor feedback. We estimate the feedback in a chemistry-climate model to have a magnitude of +0.3 W/m2/K, which could be a significant contributor to the overall climate sensitivity. About two-thirds of the feedback comes from the extratropical stratosphere below ~16 km (the lowermost stratosphere), with the rest coming from the stratosphere above ~16 km (the overworld).

Dessler, A. E.; Schoeberl, M. R.; Wang, T.; Davis, S. M.; Rosenlof, K. H.

2013-12-01

253

A Laboratory Water Vapor Laser.  

National Technical Information Service (NTIS)

A water vapor laser has been constructed that will emit coherent radiation in the far infrared. Although most construction details are typical of gas lasers, the particularly long wavelengths involved require some innovative design features. After a brief...

R. N. Chandler R. K. Likuski

1969-01-01

254

Design, fabrication and testing of porous tungsten vaporizers for mercury ion thrusters  

NASA Technical Reports Server (NTRS)

The dispersions in the characteristics, performance and reliability of vaporizers for early model 30-cm thrusters were investigated. The purpose of the paper is to explore the findings and to discuss the approaches that were taken to reduce the observed dispersion and present the results of a program which validated those approaches. The information that is presented includes porous tungsten materials specifications, a discussion of assembly procedures, and a description of a test program which screens both material and fabrication processes. There are five appendices providing additional detail in the areas of vaporizer contamination, nitrogen flow testing, bubble testing, porosimeter testing, and mercury purity. Four neutralizers, seven cathodes and five main vaporizers were successfully fabricated, tested, and operated on thrusters. Performance data from those devices is presented and indicates extremely repeatable results from using the design and fabrication procedures.

Zavesky, R.; Kroeger, E.; Kami, S.

1983-01-01

255

Packed Alumina Absorbs Hypergolic Vapors  

NASA Technical Reports Server (NTRS)

Beds of activated alumina effective as filters to remove hypergolic vapors from gas streams. Beds absorb such substances as nitrogen oxides and hydrazines and may also absorb acetylene, ethylene, hydrogen sulfide, benzene, butadiene, butene, styrene, toluene, and xoylene. Bed has no moving parts such as pumps, blowers and mixers. Reliable and energy-conservative. Bed readily adapted to any size from small portable units for use where little vapor release is expected to large stationary units for extensive transfer operations.

Thomas, J. J.; Mauro, D. M.

1984-01-01

256

Vapor deposition of hardened niobium  

DOEpatents

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.

Blocher, Jr., John M. (Columbus, OH); Veigel, Neil D. (Columbus, OH); Landrigan, Richard B. (Columbus, OH)

1983-04-19

257

Chemical vapor deposition sciences  

SciTech Connect

Chemical vapor deposition (CVD) is a widely used method for depositing thin films of a variety of materials. Applications of CVD range from the fabrication of microelectronic devices to the deposition of protective coatings. New CVD processes are increasingly complex, with stringent requirements that make it more difficult to commercialize them in a timely fashion. However, a clear understanding of the fundamental science underlying a CVD process, as expressed through computer models, can substantially shorten the time required for reactor and process development. Research scientists at Sandia use a wide range of experimental and theoretical techniques for investigating the science of CVD. Experimental tools include optical probes for gas-phase and surface processes, a range of surface analytic techniques, molecular beam methods for gas/surface kinetics, flow visualization techniques and state-of-the-art crystal growth reactors. The theoretical strategy uses a structured approach to describe the coupled gas-phase and gas-surface chemistry, fluid dynamics, heat and mass transfer of a CVD process. The software used to describe chemical reaction mechanisms is easily adapted to codes that model a variety of reactor geometries. Carefully chosen experiments provide critical information on the chemical species, gas temperatures and flows that are necessary for model development and validation. This brochure provides basic information on Sandia`s capabilities in the physical and chemical sciences of CVD and related materials processing technologies. It contains a brief description of the major scientific and technical capabilities of the CVD staff and facilities, and a brief discussion of the approach that the staff uses to advance the scientific understanding of CVD processes.

NONE

1992-12-31

258

Effects of high-pressure homogenization on the properties of starch-plasticizer dispersions and their films  

Microsoft Academic Search

The properties of starch-plasticizer (glycerol:xylitol=1:1) dispersions obtained with and without high-pressure homogenization and their corresponding films were investigated. The fully gelatinized dispersions with or without homogenization were subsequently converted into films using solution casting. The apparent viscosity of the dispersions with or without homogenization was determined. The water vapor permeability, opacity, crystalline\\/amorphous nature, and mechanical properties of these starch-based films

Zong-qiang Fu; Li-jun Wang; Dong Li; Qing Wei; Benu Adhikari

2011-01-01

259

Condensing from Vapor-Gas Mixtures.  

National Technical Information Service (NTIS)

Designing condensers for vapor-gas mixtures is far more complex than for vapors alone. This simplified design method eliminates the old trial-and-error procedures. Condensation of vapor from a vapor-gas mixture where the gas does not condense is quite dif...

F. Votta

1964-01-01

260

Breakup and vaporization of droplets under locally supersonic conditions  

NASA Astrophysics Data System (ADS)

The disruption and vaporization of simulated fuel droplets in an accelerating supersonic flow was examined experimentally in a draw-down supersonic wind tunnel. The droplets achieved supersonic velocities relative to the surrounding air to give relative Mach numbers of up to 1.8 and Weber numbers of up to 300. Mono-disperse, 100 ?m-diameter fluid droplets were generated using a droplet-on-demand generator upstream of the tunnel entrance. Direct close-up single- and multiple-exposure imaging was used to examine the features of droplet breakup and to determine the droplet velocities. Laser-induced fluorescence (LIF) imaging of the disrupting droplets was performed using acetone fluorescence to determine the dispersion of the expelled vapor. Three test liquids were employed: 2-propanol and tetraethylene glycol dimethyl ether as non-volatile fluids and a 50/50 hexanol-pentane mixture (Hex-Pen 50/50). The vapor pressure of the Hex-Pen 50/50 was sufficiently high to cause the droplet fluid to potentially become superheated in the decreased static pressure of the supersonic stream. The dynamics for 2-propanol and Hex-Pen 50/50 droplets were similar up to the point of disruption, which occurred more rapidly for the more volatile Hex-Pen 50/50. A 1D dynamic droplet model was developed to provide a first estimate of the expected droplet acceleration and velocity. The actual droplet velocities were in reasonable agreement with the model up to the point at which significant droplet disruption and mass loss commenced. The droplet deformation and breakup patterns for these supersonic flow conditions can be classified into four different flow regions characterized by changes in the Weber number with downstream distance as the droplets accelerate, however, those flow regimes and Weber number ranges were different than those seen for droplets disrupting in shock tubes. The disruption patterns were seen to be generally similar for the different fluids, though droplet disruption occurred more rapidly for the more volatile fluid. LIF imaging established the extent of the dispersion of the expelled vapor. Examination of the vapor clouds surrounding the droplets suggests that Hex-Pen 50/50 droplets had a greater rate of vaporization than 2-propanol droplets starting at approximately 2 mm downstream of the nozzle throat, where the air static pressure became lower than the liquid vapor pressure. This suggests that droplet superheating can have an effect on the extent and rate of droplet vaporization under locally supersonic conditions. The degree of vaporization for Hex-Pen 50/50 was approximately 1.3 times greater than that of the non-volatile fluids over all downstream distances in the supersonic flow.

Kim, YoungJun; Hermanson, James C.

2012-07-01

261

Cauchy's dispersion equation reconsidered : dispersion in silicate glasses.  

SciTech Connect

We formulate a novel method of characterizing optically transparent substances using dispersion theory. The refractive index is given by a generalized Cauchy dispersion equation with coefficients that are moments of the uv and ir absorptions. Mean dispersion, Abbe number, and partial dispersion are combinations of these moments. The empirical relation between index and dispersion for families of glasses appears as a consequence of Beer's law applied to the uv spectra.

Smith, D. Y.; Inokuti, M.; Karstens, W.; Physics; Univ. of Vermont; St. Michael's College

2002-01-01

262

The atmospheric water vapor line.  

NASA Astrophysics Data System (ADS)

We have measured the hydrogen and oxygen isotope composition of atmospheric water vapor periodically across the American Southwest through most of 2007. Samples were primarily collected over Albuquerque, NM on the roof of the 3-story UNM geology building on a near-daily basis with occasional sampling in southern Arizona and southern Texas. Water vapor was captured by pumping ~60 to ~600 liters of air (amount depending on dew point) through a cold trap, producing ~1mL of water. Precipitation samples were also collected in Albuquerque throughout the year and analyzed for hydrogen and oxygen isotopic composition. Isotopic compositions of both vapor and precipitation were determined by CO2 equilibration for oxygen and chromium reduction for hydrogen, with resulting gasses analyzed on a mass spectrometer. Nearly all water vapor samples lie parallel to the Global Meteoric Water Line (GMWL) but with a deuterium excess of ~17 (?D = 8?O + 17). This is true regardless of relative humidity, dew point, location, time of day, or season. Precipitation samples fall to the right of the GMWL with a slope of ~5. Within our dataset we have identified 10 pairs of vapor and precipitation samples that were collected within 24 hours. Half of these sample pairs have values consistent with equilibrium conditions at ground temperature, while the other half are not in equilibrium at any temperature. Simple modeling of nonequilibrium fractionation processes suggests that the array of precipitation samples can be derived from the array of vapor samples by equilibrium condensation followed by partial evaporation of falling raindrops. Our data suggests that atmospheric water vapor has a relatively constant deuterium excess value regardless of moisture source, degree of rainout, and/or evapotranspiration contributions.

Strong, M.; Sharp, Z. D.; Gutzler, D. S.

2008-12-01

263

When Seed Dispersal Matters  

NSDL National Science Digital Library

This peer-reviewed resource from Bioscience journal is about the varying importance of seed dispersal within plant communities. A profusion of fruit forms implies that seed dispersal plays a central role in plant ecology, yet the chance that an individual seed will ultimately produce a reproductive adult is low to infinitesimal. Extremely high variance in survival implies that variations in fruit production or transitions from seed to seedling will contribute little to population growth. The key issue is that variance in survival of plant life-history stages, and therefore the importance of dispersal, differs greatly among and within plant communities. In stable communities of a few species of long-lived plants, variances in seed and seedling survival are immense, so seed-to-seedling transitions have little influence on overall population dynamics. However, when seedlings in different circumstances have very different chances of survival--in ecological succession, for example, or when dispersed seeds escape density-dependent mortality near parent trees--the biased survival of dispersed seeds or seedlings in some places rather than others results in pervasive demographic impacts.

HENRY F. HOWE and MARIA N. MIRITI (;)

2004-07-01

264

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

NASA Astrophysics Data System (ADS)

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.

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

1993-06-01

265

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

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

266

Chemically assisted release of transition metals in graphite vaporizers for atomic spectrometry  

NASA Astrophysics Data System (ADS)

The processes associated with the vaporization of microgram samples and modifiers in a graphite tube ET AAS were investigated by the example of transition metals. The vapor absorption spectra and vaporization behavior of ?g-amounts Cd, Zn, Cu, Ag, Au, Ni, Co, Fe, Mn and Cr were studied using the UV spectrometer with CCD detector, coupled with a continuum radiation source. The pyrocoated, Ta or W lined tubes, with Ar or He as internal gases, and filter furnace were employed in the comparative experiments. It was found that the kinetics of atomic vapor release changed depending on the specific metal-substrate-gas combination; fast vaporization at the beginning was followed by slower 'tailing.' The absorption continuum, overlapped by black body radiation at longer wavelengths, accompanied the fast vaporization mode for all metals, except Cd and Zn. The highest intensity of the continuum was observed in the pyrocoated tube with Ar. For Cu and Ag the molecular bands overlapped the absorption continuum; the continuum and bands were suppressed in the filter furnace. It is concluded that the exothermal interaction of sample vapor with the material of the tube causes the energy evolution in the gas phase. The emitted heat is dispersed near the tube wall in the protective gas and partially transferred back to the surface of the sample, thus facilitating the vaporization. The increased vapor flow causes over-saturation and gas-phase condensation in the absorption volume at some distance from the wall, where the gas temperature is not affected by the reaction. The condensation is accompanied by the release of phase transition energy via black body radiation and atomic emission. The particles of condensate and molecular clusters cause the scattering of light and molecular absorption; slow decomposition of the products of the sample vapor-substrate reaction produces the 'tailing' of atomic absorption signal. The interaction of graphite with metal vapor or oxygen, formed in the decomposition of metal oxide, is the most probable source of chemical energy, which facilitates the vaporization. Intensity of the process depends on chemical properties of the sample and substrate and efficiency of mass and heat transfer by the protective gas. The discussed mechanism of chemically assisted vapor release signifies the energy exchange between all participants of the vaporization process in ET AAS including the matrix, modifier, purge gas and analyte. The finding contributes in the ET AAS theory regarding the mechanisms of vaporization and mass transfer in the presence of matrix and modifiers.

Katskov, Dmitri; Darangwa, Nicholas; Grotti, Marco

2006-05-01

267

Dispersal characteristics of swift foxes  

Microsoft Academic Search

From 1997 to 2001, we monitored movements of 109 adult and 114 juvenile swift foxes, Vulpes velox (Say, 1823), at study sites in Colorado, New Mexico, and Texas to determine patterns of dispersal. Significantly more male (93%) than female (58%) juveniles dispersed, and both sexes had similar bimodal dispersal patterns with peaks in September-October and January-February. Adult dispersal occurred more

Jan F. Kamler; Warren B. Ballard; Eric M. Gese; Robert L. Harrison; Seija M. Karki

2004-01-01

268

Kinetics of water vapor diffusion in activated carbon  

NASA Astrophysics Data System (ADS)

We describe an experimental method for studying rapid processes of water vapor sorption by fine-dispersed and porous materials. The concentration of gas-phase water molecules is detected during adsorption by a laser-diode spectrometer. The kinetic pressure curves are recorded in a time window of 10-1 to 103 s and are analyzed using analogy of the diffusion flow with the electric current in a branched RC circuit. The proposed model establishes the relation between the kinetics curves being measured and the structural parameters of the medium.

Kurmasheva, D. M.; Kapralov, P. O.; Travkin, V. D.; Artemov, V. G.; Tikhonov, V. I.; Volkov, A. A.

2014-05-01

269

Water Vapor Imagery: Water Vapor and Jet Streams  

NSDL National Science Digital Library

This is a self-paced, on-line tutorial where learners can identify and analyze jet streams using water vapor imagery from weather satellites. Learners are introduced to the concept and function of the water vapor channel and how these images compare with weather models. An optional embedded refresher tutorial with providing meteorological background information about jet streams supports student-centered investigations in three learning scenarios: a jet stream tracking challenge made by a TV meteorologist, analyzing data in a in-air turbulence scenario involving an airline pilot, and a decision-making challenge involving the launching and tracking of a weather balloon. This resource is part of the tutorial series, Satellite Observations in Science Education, and is the third of three modules in the tutorial, Water Vapor Imagery. (Note: requires Java plug-in)

270

The effect of the London-van der Waals dispersion force on interline heat transfer  

Microsoft Academic Search

A theoretical procedure to determine the heat transfer characteristics of the interline region (junction of liquid-solid-vapor) from the macroscopic optical and thermophysical properties of the system is outlined. The analysis is based on the premise that the interline transport processes are controlled by the London-van der Waals dispersion force between condensed phases (solid and liquid). Numerical values of the dispersion

P. C. Wayner Jr.

1978-01-01

271

Ordered micro-porous carbon molecular sieves containing well-dispersed platinum nanoparticles for hydrogen storage  

Microsoft Academic Search

Ordered micro-porous carbon molecular sieves containing highly dispersed platinum nanoparticles with tunable sizes from 1 to 6nm are synthesized in this work. The synthesis is simply realized by nanocasting of furfuryl alcohol precursor on Pt-impregnated NaY zeolite hard templates and complemented by chemical vapor deposition by propylene gas. During the carbonization, Pt ions can be reduced to form highly dispersed

Yun-Xia Yang; Laure Bourgeois; Chunxia Zhao; Dongyuan Zhao; Alan Chaffee; Paul A. Webley

2009-01-01

272

Drilling mud dispersants  

SciTech Connect

Dispersants useful in aqueous drilling mud formulations employed in the drilling of subterranean wells where high temperature and high pressure environments are encountered are disclosed. The dispersants, when used in amounts of about 0.1 to 25 ppb provide muds containing colloidal material suspended in an aqueous medium with improved high temperature and high pressure stability. The dispersants are water soluble sulfonated vinyl toluene-maleic anhydride copolymers which have a molar ratio of vinyl toluene to maleic anhydride of about 1:1 to less than about 2:1, a molecular weight of 1,000 to 25,000 and at least about 0.7 sulfonic acid groups per vinyl toluene unit.

Gleason, P. A.; Brase, I. E.

1985-05-21

273

Fog dispersal technology.  

NASA Technical Reports Server (NTRS)

The state-of-the-art in fog dispersal technology is briefly discussed. Fog is categorized as supercooled fog, occurring in air temperatures below freezing, and warm fog, occurring at above-freezing temperatures. Operational techniques are available to disperse supercooled fog in the airport area. It is much more difficult to cope with warm fog. Various known concepts to disperse warm fog are evaluated as to their operational merits. The most effective concept for immediate use involves heating the air to cause fog evaporation. Use of helicopter downwash has some application, possibly complementing the promising concept of seeding with sized hygroscopic particles. These latter two concepts appear to have future application, pending further research. The concept using polyelectrolytes is of uncertain value, lacking both a scientific explanation and a substantive evaluation of reported operational successes.

Mcgowan, W. A.

1971-01-01

274

Mars Atmospheric Water Vapor: 2000 Southern Summer  

NASA Astrophysics Data System (ADS)

During 1998-2000 extensive ground-based observations yielded 133 continuous, H2O vapor profiles across the Martian disk. High-dispersion, CCD echelle spectra sampled Martian atmospheric water vapor from northern spring through the start of summer in the southern hemisphere. The slit was placed either in the N-S direction along the central meridian to study the latitudinal distribution or E-W to study the diurnal behavior. Abundances will be presented for the late spring-early summer season in the southern hemisphere. Supported by NASA grant NAG5-7791. Martian Water Vapor Spectra: 1998-2000 Apparition Date Slit Slit Ls SubS Martian SubE Mars (UTC) pos pos Lat Long Lat Dia. 1998 N-S E-W (o) (o) (o) (o) (") Nov 10-12 6 - 56 20.5 88-163 25.1 4.8 Dec 8-9 3 3 68 23.3 136-180 24.2 5.4 1999 Jan 12-13 6 3 83 25.2 167-200 20.8 6.8 Jan 20-1 4 2 91 25.5 357-48 18.6 7.9 Mar 16-17 2 11 111 23.8 227-306 15.0 12.1 Mar 29 2 - 116 22.7 122-137 15.4 13.7 Jun 1-2 1 5 148 13.7 170-212 22.7 14.4 Jun 22 1 1 158 9.1 323-351 22.8 12.3 Jul 7-10 6 13 168 5.8 140-207 22.0 11.0 Jul 27-28 3 3 178 1.1 318-11 19.6 8.0 Aug 30-31 2 7 197 -7.1 314-37 12.7 8.0 Sep 23-24 5 5 212 -12.9 77-125 6.0 7.1 Nov 8-9 4 6 242 -21.9 336-33 -8.7 6.0 Nov 29-2 10 7 254 -24.3 86-161 -15.3 5.6 2000 Jan 16-17 11 - 284 -24.7 0-44 -25.4 4.8 Feb 9 4 - 298 -22.2 123-148 -26.3 4.5

Barker, E.

2000-12-01

275

Vapor pressures of new fluorocarbons  

SciTech Connect

The vapor pressures of four fluorocarbons have been measured at the following temperature ranges: R123 (2,2-dichloro-1,1,1-trifluoroethane), 273-457 K; R123a (1,2-dichloro-1,1,2-trifluoroethane), 303-458 K; R134a (1,1,1,2-tetrafluoroethane), 253-373 K; and R132b (1,2-dichloro-1,1-difluoroethane), 273-398 K. Determinations of the vapor pressure were carried out by a constant-volume apparatus with an uncertainty of less than 1.0%. The vapor pressures of R123 and R123a are very similar to those of R11 over the whole experimental temperature range, but the vapor pressures of R134a and R132b differ somewhat from those of R12 and R113, respectively, as the temperature increases. The numerical vapor pressure data can be fitted by an empirical equation using the Chebyshev polynomial with a mean deviation of less than 0.3%.

Kubota, H.; Yamashita, T.; Tanaka, Y.; Makita, T. (Kobe Univ. (Japan))

1989-05-01

276

MAMA Dispersion Solutions  

NASA Astrophysics Data System (ADS)

Wavelength dispersion solutions will be determined on a yearly basis as part of a long-term monitoring program. Deep engineering wavecals for each MAMA grating will be obtained at common cenwaves. Intermediate settings will also be taken to check the reliability of derived dispersion solutions. Final selection was determined on basis of past monitoring and C17 requirements. The internal wavelength calibrations will be taken using the LINE line lamp. Extra-deep wavecals are included for some echelle modes and first order modes to ensure detection of weak lines.;

Lennon, Daniel

2008-07-01

277

Seed Dispersal: Lemurs  

NSDL National Science Digital Library

Trees in Madagascar's forests have evolved traits that promote the dispersal of their seeds by lemurs. This two-minute radio program focuses on the interaction between forest plants and lemurs--the main seed dispersers in the forests. A guest scientist explains why lemurs ingest seeds that are large relative to their body size. He also notes that the fruits of Madagascar's trees have evolved to be strong smelling but drably colored in accordance with lemurs' keen sense of smell and poor vision. The program is available in text and audio formats. The latter includes audio of ring-tailed lemurs. Copyright 2005 Eisenhower National Clearinghouse

Planet, Pulse O.

2007-09-20

278

Development of polymer concrete for dike insulation at LNG (Liquid Natural Gas) facilities. Final report, August 1983-July 1984  

SciTech Connect

An insulating polymer concrete (IPC) composite has been developed for possible use as a dike insulation material at Liquid Natural Gas (LNG) storage facilities. Using hermetically sealed glass nodules or expanded perlite aggregates and unsaturated polyester resins, a new class of lightweight polymer concretes can be manufactured. Two application procedures have been identified and shown to be feasible in laboratory studies. Precast IPC composite panels 1-in thick can be bonded to concrete substrates using epoxy gel type adhesives or mortars. Cast-in-place IPC to concrete substrates have been shown to have good bonding and insulating characteristics. Modifications of the mix design to improve the workability and sagging of the IPC for installation on vertical or sloped surfaces is necessary.

Fontana, J.J.; Steinberg, M.

1984-11-01

279

Optimization of metal vapor lasers  

NASA Astrophysics Data System (ADS)

The method proposed here for performing numerical calculations on a computer in order to predict and optimize the characteristics of metal vapor lasers is based on the use of a universal program for numerical experiments designed expressly for metal vapor lasers and on a simultaneous application of an algorithm for multifactor optimization of the output parameters. The latter, in turn, is based on the complex Boks method (Himmelblau, 1970) and on the Gel'fand-Tsetlin ravine method (Himmelblau, 1970). Calculations carried out for a metal with a copper vapor in neon reveal that for optimization with respect to the geometry of the active zone and the parameters of the electrical circuits (including the voltage pulses and excitation frequency) it is sufficient to use the Boks method. The objective function optimum regarding the concentration of the metal particles and the buffer gas found using this algorithm calls for further refinement; this can be performed efficiently with the Gel'fand-Tsetlin ravine method.

Buchanov, V. V.; Molodykh, E. I.; Tykotskii, V. V.

1983-03-01

280

Estimating Change in Dispersion.  

ERIC Educational Resources Information Center

Statistical methods are presented for: (1) studying changes in dispersion (CID) of a dependent measure over time; (2) estimating the effects of treatments on the rate of CID; and (3) combining such estimated effects from related studies. Focus is on the logic of estimating CID using log transformation-based analyses. (SLD)

Raudenbush, Steven W.

1988-01-01

281

Phonon dispersion in graphene  

SciTech Connect

Taking into account the constraints imposed by the lattice symmetry, we calculate the phonon dispersion for graphene with interactions between the first and second nearest neighbors. We show that only five force constants give a very good fitting to the elastic constants and phonon frequencies observed in graphite.

Falkovsky, L. A. [Russian Academy of Sciences, Landau Institute for Theoretical Physics (Russian Federation)], E-mail: falk@itp.ac.ru

2007-08-15

282

Isopycnal Dispersion in NATRE  

Microsoft Academic Search

Finescale velocity and density fluctuations consist of both internal waves and vorticity-containing perturbations (vortical modes). A recent decomposition of observations obtained as part of the North Atlantic Tracer Release Experiment (NATRE) permits one to investigate isopycnal stirring associated with vortical modes. This stirring is treated here as a relative dispersion problem in the context of 2D turbulence. Isopycnal diffusivities attain

Kurt Polzin; Raffaele Ferrari

2004-01-01

283

Vapor deposition of thin films  

DOEpatents

A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl).sub.3, iridium(allyl).sub.3, molybdenum(allyl).sub.4, tungsten(allyl).sub.4, rhenium(allyl).sub.4, platinum(allyl).sub.2, or palladium(allyl).sub.2 are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

Smith, David C. (Los Alamos, NM); Pattillo, Stevan G. (Los Alamos, NM); Laia, Jr., Joseph R. (Los Alamos, NM); Sattelberger, Alfred P. (Los Alamos, NM)

1992-01-01

284

Method and apparatus for vapor detection  

NASA Technical Reports Server (NTRS)

The method disclosed herein may be practiced by passing the vapors to be sampled along a path with halogen vapor, preferably chlorine vapor, heating the mixed vapors to halogenate those of the sampled vapors subject to halogenation, removing unreacted halogen vapor, and then sensing the vapors for organic halogenated compounds. The apparatus disclosed herein comprises means for flowing the vapors, both sample and halogen vapors, into a common path, means for heating the mixed vapors to effect the halogenation reaction, means for removing unreacted halogen vapor, and a sensing device for sensing halogenated compounds. By such a method and means, the vapors of low molecular weight hydrocarbons, ketones and alcohols, when present, such as methane, ethane, acetone, ethanol, and the like are converted, at least in part, to halogenated compounds, then the excess halogen removed or trapped, and the resultant vapors of the halogenated compounds sensed or detected. The system is highly sensitive. For example, acetone in a concentration of 30 parts per billion (volume) is readily detected.

Lerner, Melvin (Inventor); Hood, Lyal V. (Inventor); Rommel, Marjorie A. (Inventor); Pettitt, Bruce C. (Inventor); Erikson, Charles M. (Inventor)

1980-01-01

285

Dispersion-managed solitons with net positive dispersion.  

PubMed

Propagation of dispersion-managed solitons in the net positive-dispersion regime is studied. A new form of sideband generation that is due to perturbations is identified. Some collision anomalies are pointed out. PMID:18087413

Chen, Y; Haus, H A

1998-07-01

286

Exponential decay of dispersion managed solitons for vanishing average dispersion  

Microsoft Academic Search

We show that any $L^2$ solution of the Gabitov-Turitsyn equation describing dispersion managed solitons decay exponentially in space and frequency domains. This confirms in the affirmative Lushnikov's conjecture of exponential decay of dispersion managed solitons.

M. Burak Erdogan; Dirk Hundertmark; Young-Ran Lee

2010-01-01

287

Microwave assisted chemical vapor infiltration.  

National Technical Information Service (NTIS)

The purpose of this program is to develop a new process for the fabrication of ceramic matrix composites by chemical vapor infiltration. This period has been devoted in part to the exploration of material systems suitable for MACVI processing. A number of...

D. J. Devlin

1993-01-01

288

Microwave assisted chemical vapor infiltration  

Microsoft Academic Search

The purpose of this program is to develop a new process for the fabrication of ceramic matrix composites by chemical vapor infiltration. This period has been devoted in part to the exploration of material systems suitable for MACVI processing. A number of potential processing schemes are possible using combinations of absorbing and transparent material as composite components. This includes the

Devlin

1993-01-01

289

Microwave assisted chemical vapor infiltration  

Microsoft Academic Search

A microwave assisted process for production of continuous fiber reinforced ceramic matrix composites is described. A simple apparatus combining a chemical vapor infiltration reactor with a conventional 700 W multimode oven is described. Microwave induced inverted thermal gradients are exploited with the ultimate goal of reducing processing times on complex shapes. Thermal gradients in stacks of SiC (Nicalon) cloths have

D. J. Devlin; R. P. Currier; R. S. Barbero; B. F. Espinoza; N. Elliott

1991-01-01

290

Film boiling chemical vapor infiltration  

Microsoft Academic Search

Several chemical vapor infiltration (CVI) processes have been developed to increase both the carbon yield and the densification rate for a controlled type of pyrocarbon deposit. Recently, the ‘film boiling technique’ (so-called Kalamazoo) has been successfully developed for making in particular C\\/C composite materials. To get a better insight on this process, we have built up two small laboratory reactors

D Rovillain; M Trinquecoste; E Bruneton; A Derré; P David; P Delhaès

2001-01-01

291

Modeling of chemical vapor infiltration  

Microsoft Academic Search

Ceramic matrix composites can be fabricated by chemical vapor infiltration (CVI) of a fibrous preform. In conventional processing, the reactant gases diffuse into the preform under isothermal conditions, depositing material onto the fibers and forming a continuous matrix as coating thickness increases. This technique usually requires several weeks to achieve high density. Recent development of a forced flow, thermal gradient

Starr

1989-01-01

292

INDOOR AIR VAPOR INTRUSION SEMINAR  

EPA Science Inventory

This seminar is sponsored by the ORD in collaboration with the Office of Solid Waste and Emergency Response. The goal of this seminar is to present information and guidance to evaluate, assess and characterize chemical vapor pathways migrating into structures resulting from conta...

293

Microfabricated alkali atom vapor cells  

Microsoft Academic Search

We describe the fabrication of chip-sized alkali atom vapor cells using silicon micromachining and anodic bonding technology. Such cells may find use in highly miniaturized atomic frequency references or magnetometers. The cells consist of cavities etched in silicon, with internal volumes as small as 1 mm3. Two techniques for introducing cesium and a buffer gas into the cells are described:

Li-Anne Liew; Svenja Knappe; John Moreland; Hugh Robinson; Leo Hollberg; John Kitching

2004-01-01

294

Water vapor adsorption on goethite.  

PubMed

Goethite (?-FeOOH) is an important mineral contributing to processes of atmospheric and terrestrial importance. Their interactions with water vapor are particularly relevant in these contexts. In this work, molecular details of water vapor (0.0-19.0 Torr; 0-96% relative humidity at 25 °C) adsorption at surfaces of synthetic goethite nanoparticles reacted with and without HCl and NaCl were resolved using vibrational spectroscopy. This technique probed interactions between surface (hydr)oxo groups and liquid water-like films. Molecular dynamics showed that structures and orientations adopted by these waters are comparable to those adopted at the interface with liquid water. Particle surfaces reacted with HCl accumulated less water than acid-free surfaces due to disruptions in hydrogen bond networks by chemisorbed waters and chloride. Particles reacted with NaCl had lower loadings below ?10 Torr water vapor but greater loadings above this value than salt-free surfaces. Water adsorption reactions were here affected by competitive hydration of coexisting salt-free surface regions, adsorbed chloride and sodium, as well as precipitated NaCl. Collectively, the findings presented in this study add further insight into the initial mechanisms of thin water film formation at goethite surfaces subjected to variations in water vapor pressure that are relevant to natural systems. PMID:23721420

Song, Xiaowei; Boily, Jean-François

2013-07-01

295

Mercury vapor determination in hospitals.  

PubMed

The measurements of metallic mercury vapor were carried out in seven local hospitals, where mercury-containing products are widely used, as well as in one residence to check effectiveness of decontamination after mercury spillage. Hopcalite as a solid sorbent was used in active and passive sampling methods, and mercury was analyzed by CV-AAS technique. Good agreement was found between results of mercury measurements using active samplers (pumped hopcalite adsorption tubes) and passive (diffusion) monitors applied in indoor atmosphere. The results indicated the presence of metallic mercury vaporization sources in the assessed hospital rooms but in the majority of cases mercury levels did not exceed 1 microg/m3 i.e. Polish permissible concentration for residence. However, in some of the hospital rooms, elevated concentrations of mercury vapor were found and airborne levels of up to 13.9 microg/m3 were recorded. Higher concentrations of mercury vapor were observed in autumn season when compared to summer. PMID:15931983

Prokopowicz, Adam; Mniszek, Wojciech

2005-05-01

296

Acoustic Behavior of Vapor Bubbles  

NASA Technical Reports Server (NTRS)

In a microgravity environment vapor bubbles generated at a boiling surface tend to remain near it for a long time. This affects the boiling heat transfer and in particular promotes an early transition to the highly inefficient film boiling regime. This paper describes the physical basis underlying attempts to remove the bubbles by means of pressure radiation forces.

Prosperetti, Andrea; Oguz, Hasan N.

1996-01-01

297

Physical vapor deposition tool coatings  

Microsoft Academic Search

Physical vapor deposition (PVD) of hard coatings such as titanium nitride have been an industrial reality since the beginning of the 1980s. Two PVD processes, low voltage electron beam and cathodic arc deposition, were responsible for the early commercial success of hard coatings on high speed steel tooling. Since that time, two other PVD processes have also been prosperous in

William D. Sproul

1996-01-01

298

Final OSWER Vapor Intrusion Guidance  

EPA Science Inventory

EPA is preparing to finalize its guidance on assessing and addressing vapor intrusion, which is defined as migration of volatile constituents from contaminated media in the subsurface (soil or groundwater) into the indoor environment. In November 2002, EPA issued draft guidance o...

299

Generalized Phase-Change Submodels in the FEM3 Model for Gas Dispersion.  

National Technical Information Service (NTIS)

FEM3 is a numerical model developed to simulate the dispersion of heavy gases in the atmosphere. A phase-change submodel was added to FEM3 to account for the phase changes of atmospheric water vapor. This phase-change submodel has been generalized as desc...

H. C. Rodean S. T. Chan

1986-01-01

300

Atomic vapor laser isotope separation process  

DOEpatents

A laser spectroscopy system is utilized in an atomic vapor laser isotope separation process. The system determines spectral components of an atomic vapor utilizing a laser heterodyne technique. 23 figs.

Wyeth, R.W.; Paisner, J.A.; Story, T.

1990-08-21

301

Water Vapor Permeability of Plastic Fast Packs.  

National Technical Information Service (NTIS)

The objective of this investigation was to perform nondestructive tests that quantitatively measured the water vapor permeability of a plastic (high density polyethylene) Type I Fast Pack design. The water vapor transmission rate (WVTR) of the new pack de...

J. A. Hincks

1978-01-01

302

Boiler for generating high quality vapor  

NASA Technical Reports Server (NTRS)

Boiler supplies vapor for use in turbines by imparting a high angular velocity to the liquid annulus in heated rotating drum. Drum boiler provides a sharp interface between boiling liquid and vapor, thereby, inhibiting the formation of unwanted liquid droplets.

Gray, V. H.; Marto, P. J.; Joslyn, A. W.

1972-01-01

303

Conversion of laser-frequency noise to optical-rotation noise in cesium vapor.  

PubMed

We have studied the noise in the optical rotation of a linearly polarized laser beam transmitted through a spin-polarized (133)Cs vapor as a function of its frequency detuning from the optical resonance. Our measurements demonstrate the direct conversion of the laser-frequency noise into optical rotation noise by the dispersive response of the atomic vapor. We describe this noise-conversion process in terms of a simple model that can be used to optimize the performance of atomic devices, such as atomic magnetometers, that use optical rotation as their operational signal. PMID:19684835

Jiménez-Martínez, Ricardo; Knappe, Svenja; Griffith, W Clark; Kitching, John

2009-08-15

304

Nikolaevskiy equation with dispersion  

NASA Astrophysics Data System (ADS)

The Nikolaevskiy equation was originally proposed as a model for seismic waves and is also a model for a wide variety of systems incorporating a neutral “Goldstone” mode, including electroconvection and reaction-diffusion systems. It is known to exhibit chaotic dynamics at the onset of pattern formation, at least when the dispersive terms in the equation are suppressed, as is commonly the practice in previous analyses. In this paper, the effects of reinstating the dispersive terms are examined. It is shown that such terms can stabilize some of the spatially periodic traveling waves; this allows us to study the loss of stability and transition to chaos of the waves. The secondary stability diagram (“Busse balloon”) for the traveling waves can be remarkably complicated.

Simbawa, Eman; Matthews, Paul C.; Cox, Stephen M.

2010-03-01

305

Improved Gravimetric Vapor-Sorption Apparatus  

Microsoft Academic Search

This improved gravimetric vapor-sorption apparatus was designed for vapor-sorption measurements at 20–50°C with condensable vapors, e.g., water and organic vapors on inorganic and organic adsorbents, such as minerals and resins. The apparatus can be readily adapted to low-temperature adsorption of noncondensable gases, e.g., N2, Kr, and Ar. The system consisted of a helical spring (quartz or tungsten) sorption balance. A

C. S. Brooks

1961-01-01

306

Magnetostatic wave dispersion relations  

NASA Astrophysics Data System (ADS)

The results presented here summarize and expand earlier results for magnetostatic wave dispersion relations and for magnetostatic wave oscillators. In what follows is presented the disperson relations for generalized volume waves and generalized surface waves for a thin YIG film bounded by two ground planes. Computer produced curves for volume waves and surface waves are presented. Also presented is a comparison between a theoretically obtained disperson curve for surface waves and one obtained by computer controlled experiment at RADC, Hanscom AFB.

Weinberg, I. J.

1983-01-01

307

Ascent trajectory dispersion analysis  

NASA Technical Reports Server (NTRS)

The results of a Space Transportation System ascent trajectory dispersion analysis are documented. Critical trajectory parameter values useful for the definition of lightweight external tank insulation requirements are provided. This analysis was conducted using two of the critical missions specified for the Space Transportation System: a 28.5 deg inclination trajectory launched from the Eastern Test Range (ETR) and a Western Test Range (WTR) trajectory launched into a 104 deg orbital inclination.

1982-01-01

308

Confined zone dispersion flue gas desulfurization demonstration  

SciTech Connect

The confined zone dispersion (CZD) process involves flue gas post-treatment, physically located between a boiler's outlet and its particulate collector, which in the majority of cases is an electrostatic precipitator. The features that distinguish this process from other similar injection processes are: Injection of an alkaline slurry directly into the duct, instead of injection of dry solids into the duct ahead of a fabric filter. Use of an ultrafine calcium/magnesium hydroxide, type S pressure-hydrated dolomitic lime. This commercial product is made from plentiful, naturally occurring dolomite. Low residence time, made possible by the high effective surface area of the Type S lime. Localized dispersion of the reagent. Slurry droplets contact only part of the gas while the droplets are drying, to remove up to 50 percent of the S0{sub 2} and significant amounts of NO{sub x}. The process uses dual fluid rather than rotary atomizers. Improved electrostatic precipitator performance via gas conditioning from the increased water vapor content, and lower temperatures. Supplemental conditioning with S0{sub 3} is not believed necessary for satisfactory removal of particulate matter.

Not Available

1992-02-27

309

Dispersibility of Amphibious Montmorillonite  

NASA Astrophysics Data System (ADS)

The objective of this study is to develop a suitable method to convert hydrophilic montmorillonite into amphibious montmorillonite by replacing the sodium ions normally found in clay with poly(oxyethylene) (POE)-amide chlorite cations. Amphibious montmorillonite has a high d-spacing and good dispersion characteristics in many different types of solutions, including those having an intermediate hydrophilic lipophilic balance (HLB) value. Four different modifying cations are tested and X-ray diffraction analysis is performed to measure the resulting changes in the d-spacing of the MMT. Scanning electron microscopy is employed to investigate the morphology of the modified clays. A laser-doppler particle analyzer is used to measure the particle size of the clays in various solutions. Dobrat’s method is applied to calculate the dispersibility of each clay and Stoke’s law is used to evaluate the settling rate. The results indicate that the d-spacing of the POE-amide chlorite cation modified montmorillonite increases from 1.28 to 3.51 nm. The amphibious montmorillonite demonstrates good dispersion characteristics in eight commonly employed coating solutions with intermediate HLB values.

Yeh, Meng-Heng; Hwang, Weng-Sing; Kuo, Wuei-Jueng

2005-09-01

310

Succinimide lubricating oil dispersant  

SciTech Connect

A lubricating oil composition is described exhibiting improved dispersancy in both gasoline and diesel engines comprising a major amount of lubricating oil and 0.5 to 10 weight percent of a dispersant, the dispersant being prepared in a sequential process comprising the steps of: (a) in a first step reacting an oil-soluble polyolefin succinic anhydride, the olefin being a C/sub 3/ or C/sub 4/ olefin and an alkylene polyamine of the formula H/sub 2/N(CH/sub 2/)/sub n/(NH(CH/sub 2/)/sub n/)/sub m/sup -// NH/sub 2/ wherein n is 2 or 3 and m is 0 to 10, in a molar ratio of about 1.0 to 2.2 moles of polyolefin succinic anhydride per mole of polyamine, and (b) reacting the product of step (a) with dicarboxylic acid anhydride selected from the group consisting of maleic anhydride and succinic anhydride in sufficient molar proportions to provide a total mole ratio of about 2,3 to 3.0 moles of anhydride compounds per mole of polyamine.

Wisotsky, M.J.; Bloch, R.; Brownwell, D.W.; Chen, F.J.; Gutierrez, A.

1987-08-11

311

Vapor Pressure Measurements in a Closed System  

ERIC Educational Resources Information Center

An alternative method that uses a simple apparatus to measure vapor pressure versus temperature in a closed system, in which the total pressure is the vapor pressure of the liquid sample, is described. The use of this apparatus gives students a more direct picture of vapor pressure than the isoteniscope method and results have generally been quite…

Iannone, Mark

2006-01-01

312

Preparation Of Sources For Plasma Vapor Deposition  

NASA Technical Reports Server (NTRS)

Multicomponent metal targets serving as sources of vapor for plasma vapor deposition made in modified pressureless-sintering process. By use of targets made in modified process, one coats components with materials previously plasma-sprayed or sintered but not plasma-vapor-deposited.

Waters, William J.; Sliney, Hal; Kowalski, D.

1993-01-01

313

Dispersion-managed solitons at normal average dispersion  

SciTech Connect

We find that in a dispersion-managed fiber, in which the strength of the dispersion management is above some threshold, solitons can exist with normal average dispersion. When the normal average dispersion is below some limiting value there exist two soliton solutions with the same pulse duration and different pulse energies. When the normal average dispersion is above this limiting value, no soliton exists. Both higher-energy and lower-energy solitons are dynamically stable in the parameter range that we considered. {copyright} {ital 1998} {ital Optical Society of America}

Grigoryan, V.S.; Menyuk, C.R. [Department of Computer Science and Electrical Engineering, University of Maryland Baltimore County, Baltimore, Maryland 21250 (United States)

1998-04-01

314

Dispersion-managed solitons at normal average dispersion.  

PubMed

We find that in a dispersion-managed fiber, in which the strength of the dispersion management is above some threshold, solitons can exist with normal average dispersion. When the normal average dispersion is below some limiting value there exist two soliton solutions with the same pulse duration and different pulse energies. When the normal average dispersion is above this limiting value, no soliton exists. Both higher-energy and lower-energy solitons are dynamically stable in the parameter range that we considered. PMID:18084592

Grigoryan, V S; Menyuk, C R

1998-04-15

315

Nozzle for electric dispersion reactor  

DOEpatents

A nozzle for an electric dispersion reactor includes two coaxial cylindrical bodies, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode. 5 figs.

Sisson, W.G.; Harris, M.T.; Scott, T.C.; Basaran, O.A.

1996-04-02

316

Nozzle for electric dispersion reactor  

DOEpatents

A nozzle for an electric dispersion reactor includes two concentric electrodes, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode. 4 figs.

Sisson, W.G.; Basaran, O.A.; Harris, M.T.

1995-11-07

317

Nozzle for electric dispersion reactor  

DOEpatents

A nozzle for an electric dispersion reactor includes two concentric electrodes, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode.

Sisson, Warren G. (Oak Ridge, TN); Basaran, Osman A. (Oak Ridge, TN); Harris, Michael T. (Knoxville, TN)

1995-01-01

318

Nozzle for electric dispersion reactor  

DOEpatents

A nozzle for an electric dispersion reactor includes two coaxial cylindrical bodies, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode.

Sisson, Warren G. (Oak Ridge, TN); Harris, Michael T. (Knoxville, TN); Scott, Timothy C. (Knoxville, TN); Basaran, Osman A. (Oak Ridge, TN)

1998-01-01

319

Nozzle for electric dispersion reactor  

DOEpatents

A nozzle for an electric dispersion reactor includes two concentric electrodes, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode.

Sisson, Warren G. (Oak Ridge, TN); Basaran, Osman A. (Oak Ridge, TN); Harris, Michael T. (Knoxville, TN)

1998-01-01

320

Nozzle for electric dispersion reactor  

DOEpatents

A nozzle for an electric dispersion reactor includes two coaxial cylindrical bodies, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode.

Sisson, Warren G. (Oak Ridge, TN); Harris, Michael T. (Knoxville, TN); Scott, Timothy C. (Knoxville, TN); Basaran, Osman A. (Oak Ridge, TN)

1996-01-01

321

How accurate are dispersion predictions  

Microsoft Academic Search

Past widespread use of Gaussian dispersion models to predict stack gas plume dispersions has led to the misconception that dispersion models predict plume concentrations within a factor of two or three of real world concentrations. The consistent prediction of actual plume concentrations within a factor of 10 is a more realistic assessment for the short time models. Constraints and assumptions

Beychok

1979-01-01

322

Nozzle for electric dispersion reactor  

DOEpatents

A nozzle for an electric dispersion reactor includes two coaxial cylindrical bodies, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode. 5 figs.

Sisson, W.G.; Harris, M.T.; Scott, T.C.; Basaran, O.A.

1998-06-02

323

Nozzle for electric dispersion reactor  

DOEpatents

A nozzle for an electric dispersion reactor includes two concentric electrodes, the inner one of the two delivering disperse phase fluid into a continuous phase fluid. A potential difference generated by a voltage source creates a dispersing electric field at the end of the inner electrode. 4 figs.

Sisson, W.G.; Basaran, O.A.; Harris, M.T.

1998-04-14

324

Terahertz Spectroscopy of Water Vapors, Chemical Vapors and Ionized Air  

NASA Astrophysics Data System (ADS)

In the past, a few research groups have demonstrated that terahertz spectroscopy could be a useful tool for the identification of chemicals. However most of those demonstrations have been done with solid-phase or liquid-phase chemicals. There are little demonstrations for the detection and identification of chemicals in the gas-phase, as it is very difficult in part due to the presence of water-absorption lines in the terahertz frequency range. As the water absorption lines predominate in the 0.1 - 2THz spectral range, and can interfere with already weak terahertz signatures generated by chemical vapors, it is often very hard to obtain meaningful terahertz spectrum of chemical vapor. Regardless we recently have been able to obtain some terahertz spectra of chemical vapors and ionized air produced by several different ionization sources, including corona discharge and nuclear isotopes. Throughout data analysis we learned that water molecules, nitrogen and oxygen molecules play very important roles in these terahertz spectra. In this presentation we will discuss our experiments and the roles of these molecules.

Graber, Benjamin; Tao, Rongjia; Wu, Dong Ho

2013-03-01

325

Size-dependent phase transition temperatures of dispersed systems  

NASA Astrophysics Data System (ADS)

A phase transition equation on the basis of the additional pressure on the curved surfaces of dispersed systems has been proposed, and the specific differential equations for various kinds of phase transitions of dispersed systems have been derived by the phase transition equation. Applying the fusion transition equations, the melting temperatures of Au and Sn nanoparticles have been calculated, and the predicted melting temperatures are in good agreement with the available experimental data. The results show that the phase transition equations can be used to predict the temperatures of phase transitions of dispersed systems and to explain the phenomenon of metastable states; the size of the dispersed phase has noticeable effect on the phase transition temperature; all temperatures of fusion, solidification, condensation, vaporization, sublimation and desublimation decrease with decreasing radius of the dispersed phase, but the bubble point temperature of a planar liquid increases with decreasing absolute value of radius of the bubbles; the depression of melting temperature for a nanowire is approximately half of that for a spherical nanoparticle with identical radius.

Xue, Yong-Qiang; Zhao, Miao-Zhi; Lai, Wei-Peng

2013-01-01

326

Modeling dispersion in optical fibers: applications to dispersion tailoring and dispersion compensation  

Microsoft Academic Search

The phenomenon of temporal pulse dispersion, which is a key characteristic of an optical fiber communication system is described\\u000a from the first principles. Beginning with the basics of dispersion in a bulk medium, these concepts are then applied to propagation\\u000a of a pulse in an optical fiber. Details of modeling dispersion are then described in the context of dispersion tailoring

K. Thyagarajan; B. P. Pal

327

Modeling dispersion in optical fibers: applications to dispersion tailoring and dispersion compensation  

Microsoft Academic Search

The phenomenon of temporal pulse dispersion, which is a key characteristic of an optical fiber communication system is described\\u000a from the first principles. Beginning with the basics of dispersion in a bulk medium, these concepts are then applied to propagation\\u000a of a pulse in an optical fiber. Details of modeling dispersion are then described in the context of dispersion tailoring

K. Thyagarajan; B. P. Pal

2007-01-01

328

(VDA) Vapor Diffusion Apparatus Tray  

NASA Technical Reports Server (NTRS)

These Vapor Diffusion Apparatus (VDA) trays were first flown in the Thermal Enclosure System (TES) during the USMP-2 (STS-62) mission. Each tray can hold 20 protein crystal growth chambers. Each chamber contains a double-barrel syringe; one barrel holds protein crystal solution and the other holds precipitant agent solution. During the microgravity mission, a torque device is used to simultaneously retract the plugs in all 20 syringes. The two solutions in each chamber are then mixed. After mixing, droplets of the combined solutions are moved onto the syringe tips so vapor diffusion can begin. During the length of the mission, protein crystals are grown in the droplets. Shortly before the Shuttle's return to Earth, the experiment is deactivated by retracting the droplets containing protein crystals, back into the syringes.

1994-01-01

329

Evaporation by mechanical vapor recompression  

NASA Astrophysics Data System (ADS)

Progress in the development of a study of the application of the technologies of mechanical vapor recompression and falling film evaporation as applied to the beet sugar industry is reported. Progress is reported in the following areas: technical literature search; report on visit to European factories using these technologies; energy balance studies of factories offered by the industry as candidates for the demonstration plants; and report on energy balance studies and the recommendations as to the site for the demonstration plant.

Iverson, C. H.; Coury, G. E.

1980-04-01

330

Advanced Vapor-Supply Manifold  

NASA Technical Reports Server (NTRS)

Advanced vapor-supply manifold solves problem of manifold purging. Design virtually eliminates dead gas volumes in manifold system. System incorporates special valve into manifold in way that leaks and contamination problems of previous systems, which use tees and three-port valves, are minimized or eliminated in both main manifold line and in supply line. Of considerable use in gas manifold systems where even small amounts of gaseous impurities constitute problem or where more than one gaseous material used in single system.

Clark, I. O.; Debnam, William J., Jr.; Fripp, Archibald L., Jr.; Crouch, R. K.

1986-01-01

331

Vaporization Would Cool Primary Battery  

NASA Technical Reports Server (NTRS)

Temperature of discharging high-power-density primary battery maintained below specified level by evaporation of suitable liquid from jacket surrounding battery, according to proposal. Pressure-relief valve regulates pressure and boiling temperature of liquid. Less material needed in cooling by vaporization than in cooling by melting. Technique used to cool batteries in situations in which engineering constraints on volume, mass, and location prevent attachment of cooling fins, heat pipes, or like.

Bhandari, Pradeep; Miyake, Robert N.

1991-01-01

332

Studies on Vapor Adsorption Systems  

NASA Technical Reports Server (NTRS)

The project consisted of performing experiments on single and dual bed vapor adsorption systems, thermodynamic cycle optimization, and thermal modeling. The work was described in a technical paper that appeared in conference proceedings and a Master's thesis, which were previously submitted to NASA. The present report describes some additional thermal modeling work done subsequently, and includes listings of computer codes developed during the project. Recommendations for future work are provided.

Shamsundar, N.; Ramotowski, M.

1998-01-01

333

CC Cryostat Vapor Pressure Thermometers  

SciTech Connect

Vapor pressure thermometers will be used to measure the temperature or the liquid argon in the cryostat at two different levels. One bulb will be positioned near the top of the vessel, and a second bulb will be located near the bottom of the vessel. The volume of the bulbs is dependent upon the charge temperature and pressure chosen, the temperature range of the thermometer desired, the size and length of tubing used, and the warm volume involved.

Kurita, C.H.; /Fermilab

1987-10-01

334

Explosive vaporization of small droplets  

SciTech Connect

A model has been created of the explosive vaporization of small droplets by the absorption of energy from a high energy laser beam. The model consists of a polarizable drop of fluid interacting with laser radiation. A criterion for the explosion of the droplet has been introduced. Selfsimilarity is invoked to reduce the spherically symmetric problem involving hydrodynamics and Maxwell's equations to simple quadrature. Experimental evidence in favor of the model is cited.

Chitanvis, S.M.

1986-08-19

335

Internal Water Vapor Photoacoustic Calibration  

NASA Technical Reports Server (NTRS)

Water vapor absorption is ubiquitous in the infrared wavelength range where photoacoustic trace gas detectors operate. This technique allows for discontinuous wavelength tuning by temperature-jumping a laser diode from one range to another within a time span suitable for photoacoustic calibration. The use of an internal calibration eliminates the need for external calibrated reference gases. Commercial applications include an improvement of photoacoustic spectrometers in all fields of use.

Pilgrim, Jeffrey S.

2009-01-01

336

Means and method for vapor generation  

DOEpatents

A liquid, in heat transfer contact with a surface heated to a temperature well above the vaporization temperature of the liquid, will undergo a multiphase (liquid-vapor) transformation from 0% vapor to 100% vapor. During this transition, the temperature driving force or heat flux and the coefficients of heat transfer across the fluid-solid interface, and the vapor percentage influence the type of heating of the fluid--starting as "feedwater" heating where no vapors are present, progressing to "nucleate" heating where vaporization begins and some vapors are present, and concluding with "film" heating where only vapors are present. Unstable heating between nucleate and film heating can occur, accompanied by possibly large and rapid temperature shifts in the structures. This invention provides for injecting into the region of potential unstable heating and proximate the heated surface superheated vapors in sufficient quantities operable to rapidly increase the vapor percentage of the multiphase mixture by perhaps 10-30% and thereby effectively shift the multiphase mixture beyond the unstable heating region and up to the stable film heating region.

Carlson, Larry W. (Oswego, IL)

1984-01-01

337

Measurements of vaporized and liquid fuel concentration fields in a burning spray jet of acetone using planar laser induced fluorescence  

Microsoft Academic Search

Planar LIF of acetone has been performed in the near development field of a burning spray jet. The main difficulty of such investigations comes from the large range of signal levels provided by the vapor and the size dispersed spray, which cannot be covered by the camera dynamics. The key point of the present work lies in a strong compression

R. Bazile; D. Stepowski

1995-01-01

338

Acoustic Droplet Vaporization through PDMS  

NASA Astrophysics Data System (ADS)

Acoustic droplet vaporization (ADV) involves the generation of bubbles from albumin-encapsulated perfluorocarbon (PFC) droplets that have been insonated with high intensity ultrasound (US). Gas embolotherapy, utilizing ADV, may facilitate occlusion of blood flow in the vasculature as bubbles undergo volume expansion of up to 125 times. Cancer therapy could benefit from such occlusions through starvation of the tumor. In order to visualize the detailed mechanics of vaporization and expansion process of the PFC droplets, idealized microvessels were constructed using polydimethylsiloxane (PDMS) channels. Microchannels (20 micron diameter) were fabricated using PDMS with polymer-crosslinker mixing ratios ranging from 5:1 to 20:1. Droplets were introduced into the channels and exposed to US for vaporization. Mixing ratios were observed to impact the impedance matching at the water-PDMS interface, which affected the threshold for ADV. The threshold was lowest for mixing ratios of 5:1 and 20:1, and greatest for 9:1. Final bubble volumes were compared with a computational model by Ye & Bull and were found to be consistent. This work is supported by NIH grant R01EB006476.

Li, David; Samuel, Stanley; Fowlkes, J. Brian; Bull, Joseph

2009-11-01

339

Water vapor diffusion membrane development  

NASA Technical Reports Server (NTRS)

An application of the water vapor diffusion technique is examined whereby the permeated water vapor is vented to space vacuum to alleviate on-board waste storage and provide supplemental cooling. The work reported herein deals primarily with the vapor diffusion-heat rejection (VD-HR) as it applies to the Space Shuttle. A stack configuration was selected, designed and fabricated. An asymmetric cellulose acetate membrane, used in reverse osmosis application was selected and a special spacer was designed to enhance mixing and promote mass transfer. A skid-mount unit was assembled from components used in the bench unit although no attempt was made to render it flight-suitable. The operating conditions of the VD-HR were examined and defined and a 60-day continuous test was carried out. The membranes performed very well throughout the test; no membrane rupture and no unusual flux decay was observed. In addition, a tentative design for a flight-suitable VD-HR unit was made.

Tan, M. K.

1977-01-01

340

Sound Propagation in Gas-Vapor-Droplet Suspensions with Evaporation and Nonlinear Particle Relaxation  

NASA Technical Reports Server (NTRS)

The Sound attenuation and dispersion in saturated gas-vapor-droplet mixture in the presence of evaporation has been investigated theoretically. The theory is based on an extension of the work of Davidson to accommodate the effects of nonlinear particle relaxation processes of mass, momentum and energy transfer on sound attenuation and dispersion. The results indicate the existence of a spectral broadening effect in the attenuation coefficient (scaled with respect to the peak value) with a decrease in droplet mass concentration. It is further shown that for large values of the droplet concentration the scaled attenuation coefficient is characterized by a universal spectrum independent of droplet mass concentration.

Kandula, Max

2012-01-01

341

Dispersion in Solids  

NASA Astrophysics Data System (ADS)

To make good use of the physical properties of nanoparticles (see Part II of this book), most applications require them to be incorporated within solid materials, such as glasses, ceramics, oxides, etc. The inclusions obtained in this way are thereby protected from chemical (e.g., oxidation) or mechanical (e.g., friction or wear) alteration due to the environment. They are also separated from one another from an electrical or magnetic point of view, which limits this kind of interaction between the particles. The dispersion of particles within solid materials can be achieved in the ordinary way by exploiting precipitation effects in the solid state (e.g., alloys hardened by dispersions of nanometric precipitates, Guinier-Preston zones), but also by a great many less direct methods. Which method is finally chosen depends on several factors such as the kind of matrix and size, shape and spatial organisation of the particles, but also on the volume of material to be produced, the cost, and the difficulty involved in the process.

Babonneau, D.

342

Rapid chemical vapor deposition of superconducting YBa sub 2 Cu sub 3 O sub x  

SciTech Connect

A process has been developed that enables the rapid chemical vapor deposition of superconducting YBa{sub 2}Cu{sub 3}O{sub {ital x}}. In this process a finely ground mixture of Y(tmhd){sub 3}, Ba(tmhd){sub 2}, and Cu(tmhd){sub 2} (tmhd=2,2,6,6-tetramethyl-3,5-heptanedionate) is slowly fed, and pneumatically transported, directly into the chemical vapor deposition furnace. Because vaporizers are not used, the number of process parameters that must be controlled is greatly reduced. Deposition rates are at least an order of magnitude greater than those achieved by reagent sublimation. Films have been characterized by scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, and resistance versus temperature measurements. Films produced on planar MgO substrates have {ital T}{sub {ital c}} values that are significantly higher than previously reported for MgO.

Lackey, W.J.; Carter, W.B.; Hanigofsky, J.A.; Hill, D.N.; Barefield, E.K.; Neumeier, G.; O'Brien, D.F.; Shapiro, M.J.; Thompson, J.R.; Green, A.J.; Moss, T.S. III (Georgia Institute of Technology, Atlanta, Georgia 30332 (USA)); Jake, R.A.; Efferson, K.R. (American Magnetics, Inc., Oak Ridge, Tennessee 37831-2509 (USA))

1990-03-19

343

Mechanical and physical properties of epoxy composites reinforced by vapor grown carbon nanofibers  

Microsoft Academic Search

Epoxy\\/vapor grown carbon nanofiber composites (VGCF) with different proportions of VGCF were fabricated by the in situ process.The VGCFs were well dispersed in both of the low and high viscosity epoxy matrices, although occasional small aggregates were observed in a high viscosity epoxy of 20wt.%. The dynamic mechanical behavior of the nanocomposite sheets was studied. The storage modulus and the

Young-Kuk Choi; Koh-ichi Sugimoto; Sung-Moo Song; Yasuo Gotoh; Yutaka Ohkoshi; Morinobu Endo

2005-01-01

344

Sintering behavior of ultrafine silicon carbide powders obtained by vapor phase reaction  

NASA Technical Reports Server (NTRS)

The sintering behavior of ultrafine SiC powder with average particle size of about 0.01-0.06 microns produced by a vapor phase reaction of the Me4Si-H2 system was studied at the temperature range of 1400-2050 deg. It was found that the homogeneous dispersion of C on SiC particles is important to remove the surface oxide layer effectively. B and C and inhibitive effect on SiC grain growth.

Okabe, Y.; Miyachi, K.; Hojo, J.; Kato, A.

1984-01-01

345

Dispersion toughened ceramic composites and method for making same  

DOEpatents

Ceramic composites exhibiting increased fracture toughness are produced by the simultaneous codeposition of silicon carbide and titanium disilicide by chemical vapor deposition. A mixture of hydrogen, methyltrichlorosilane and titanium tetrachloride is introduced into a furnace containing a substrate such as graphite or silicon carbide. The thermal decomposition of the methyltrichlorosilane provides a silicon carbide matrix phase and the decomposition of the titanium tetrachloride provides a uniformly dispersed second phase of the intermetallic titanium disilicide within the matrix phase. The fracture toughness of the ceramic composite is in the range of about 6.5 to 7.0 MPa..sqrt..m which represents a significant increase over that of silicon carbide.

Stinton, D.P.; Lackey, W.J.; Lauf, R.J.

1984-09-28

346

Optimal dispersion and central places  

NASA Astrophysics Data System (ADS)

This paper presents research into optimal dispersion models as applied to central places. The literature regarding location optimization and central places is reviewed and the motivation for employing dispersion models is identified. Models that employ the objective of maximal dispersion in the context of central places are formulated and solved in the context of both single- and multiple-good systems. Two methods for generating multiple-good systems are presented: a multiple-type dispersion model and a K-value constraint set formulation. Sequential solutions to dispersion models demonstrate how a system of central places could develop over time. The solutions to these models generate the patterns of central places expected under the organizing principles of central place theory. The objective of maximal dispersion is posited as both a motivating factor in central place location decisions, and as the optimal outcome of a mature system of central places.

Curtin, Kevin M.; Church, Richard L.

2007-06-01

347

Acoustic Rectification in Dispersive Media  

NASA Technical Reports Server (NTRS)

It is shown that the shapes of acoustic radiation-induced static strain and displacement pulses (rectified acoustic pulses) are defined locally by the energy density of the generating waveform. Dispersive properties are introduced analytically by assuming that the rectified pulses are functionally dependent on a phase factor that includes both dispersive and nonlinear terms. The dispersion causes an evolutionary change in the shape of the energy density profile that leads to the generation of solitons experimentally observed in fused silica.

Cantrell, John H.

2008-01-01

348

Particle Methods for Dispersive Equations  

Microsoft Academic Search

We introduce a new dispersion-velocity particle method for approximating solutions of linear and nonlinear dispersive equations. This is the first time in which particle methods are being used for solving such equations. Our method is based on an extension of the diffusion-velocity method of Degond and Mustieles (SIAM J. Sci. Stat. Comput.11(2), 293 (1990)) to the dispersive framework. The main

Alina Chertock; Doron Levy

2001-01-01

349

Vapor Compression Distillation Flight Experiment  

NASA Technical Reports Server (NTRS)

One of the major requirements associated with operating the International Space Station is the transportation -- space shuttle and Russian Progress spacecraft launches - necessary to re-supply station crews with food and water. The Vapor Compression Distillation (VCD) Flight Experiment, managed by NASA's Marshall Space Flight Center in Huntsville, Ala., is a full-scale demonstration of technology being developed to recycle crewmember urine and wastewater aboard the International Space Station and thereby reduce the amount of water that must be re-supplied. Based on results of the VCD Flight Experiment, an operational urine processor will be installed in Node 3 of the space station in 2005.

Hutchens, Cindy F.

2002-01-01

350

Overview of chemical vapor infiltration  

SciTech Connect

Chemical vapor infiltration (CVI) is developing into a commercially important method for the fabrication of continuous filament ceramic composites. Current efforts are focused on the development of an improved understanding of the various processes in CVI and its modeling. New approaches to CVI are being explored, including pressure pulse infiltration and microwave heating. Material development is also proceeding with emphasis on improving the oxidation resistance of the interfacial layer between the fiber and matrix. This paper briefly reviews these subjects, indicating the current state of the science and technology.

Besmann, T.M.; Stinton, D.P.; Lowden, R.A.

1993-06-01

351

Wick for metal vapor laser  

DOEpatents

An improved wick for a metal vapor laser is made of a refractory metal cylinder, preferably molybdenum or tungsten for a copper laser, which provides the wicking surface. Alternately, the inside surface of the ceramic laser tube can be metalized to form the wicking surface. Capillary action is enhanced by using wire screen, porous foam metal, or grooved surfaces. Graphite or carbon, in the form of chunks, strips, fibers or particles, is placed on the inside surface of the wick to reduce water, reduce metal oxides and form metal carbides.

Duncan, David B. (Livermore, CA)

1992-01-01

352

Vapor phase heat transport systems  

SciTech Connect

Vapor phase heat-transport systems are being tested in two of the passive test cells at Los Alamos. The systems consist of an active fin-and-tube solar collector and a condenser inside a water storage tank. The refrigerant, R-11, can be returned to the collector by a pump or by a self-pumping scheme. In one of the test cells the liquid was self-pumped to the roof-mounted collector 17 ft above the condenser. A mechanical valve was designed and tested that showed that the system could operate in a completely passive mode. Performance comparisons have been made with a passive water wall test cell.

Hedstrom, J.C.

1984-01-01

353

Water vapor diffusion membrane development  

NASA Technical Reports Server (NTRS)

A total of 18 different membranes were procured, characterized, and tested in a modified bench-scale vapor diffusion water reclamation unit. Four membranes were selected for further studies involving membrane fouling. Emphasis was placed on the problem of flux decline due to membrane fouling. This is discussed in greater details under "Summary and Discussion on Membrane Fouling Studies" presented in pages 47-51. The system was also investigated for low temperature application on wash-water where the permeated water is not recovered but vented into space vacuum.

Tan, M. K.

1976-01-01

354

Advanced Raman water vapor lidar  

NASA Technical Reports Server (NTRS)

Water vapor and aerosols are important atmospheric constituents. Knowledge of the structure of water vapor is important in understanding convective development, atmospheric stability, the interaction of the atmosphere with the surface, and energy feedback mechanisms and how they relate to global warming calculations. The Raman Lidar group at the NASA Goddard Space Flight Center (GSFC) developed an advanced Raman Lidar for use in measuring water vapor and aerosols in the earth's atmosphere. Drawing on the experience gained through the development and use of our previous Nd:YAG based system, we have developed a completely new lidar system which uses a XeF excimer laser and a large scanning mirror. The additional power of the excimer and the considerably improved optical throughput of the system have resulted in approximately a factor of 25 improvement in system performance for nighttime measurements. Every component of the current system has new design concepts incorporated. The lidar system consists of two mobile trailers; the first (13m x 2.4m) houses the lidar instrument, the other (9.75m x 2.4m) is for system control, realtime data display, and analysis. The laser transmitter is a Lambda Physik LPX 240 iCC operating at 400 Hz with a XeF gas mixture (351 nm). The telescope is a .75m horizontally mounted Dall-Kirkham system which is bore sited with a .8m x 1.1m elliptical flat which has a full 180 degree scan capability - horizon to horizon within a plane perpendicular to the long axis of the trailer. The telescope and scan mirror assembly are mounted on a 3.65m x .9m optical table which deploys out the rear of the trailer through the use of a motor driven slide rail system. The Raman returns from water vapor (403 nm), nitrogen (383 nm) and oxygen (372 nm) are measured in addition to the direct Rayleigh/Mie backscatter (351). The signal from each of these is split at about a 5/95 ratio between two photomultiplier detectors. The 5 percent detector is used for measurements below about 4.0 km, while the 95 percent detector provides the information above this level.

Whiteman, David N.; Melfi, S. Harvey; Ferrare, Richard A.; Evans, Keith A.; Ramos-Izquierdo, Luis; Staley, O. Glenn; Disilvestre, Raymond W.; Gorin, Inna; Kirks, Kenneth R.; Mamakos, William A.

1992-01-01

355

Water vapor in protoplanetary disks  

NASA Astrophysics Data System (ADS)

This thesis is devoted to a study of the conditions and evolution of the planet formation region in young circumstellar disks, by means of spectroscopic observations of molecular gas emission. The main focus of this work is the infrared spectrum of water (H2O), which provides thousands of emission lines tracing the warm and dense gas inward of the water snow line in disks. The analysis includes also emission from some organic molecules that trace the carbon chemistry, C2H2, HCN, and CO2, as well as emission from OH that is connected to the formation and destruction of the water molecule. Two are the main directions explored in this work, for which we used spectra from the Spitzer Space Telescope (IRS) and the Very Large Telescope (VISIR and X-shooter). The first is to investigate how variable accretion phenomena occurring during the T Tauri phase affect the molecular environments in the planet formation region of disks. By monitoring T Tauri stars in different phases of accretion, we found that outbursts can remarkably affect their mid-infrared molecular emission. We propose a scenario where accretion flares trigger a recession of the water snow line, increasing water emission from the disk, when the accretion luminosity keeps higher over long enough timescales for the thermal structure of the disk to change (at least a few weeks, as observed in the strongly variable EX Lupi). In addition, enhanced UV radiation is found to produce OH from photodissociation of water in the disk. Organic molecules instead disappear during a strong outburst, and we are currently investigating the long-term evolution of these effects. A second direction was taken to tackle another fundamental problem: the origin of water vapor in inner disks. Some models predict that water is produced by evaporation of icy solids migrating inward of the snow line. One way to probe this scenario is by measuring the abundance of water vapor in the inner disk, and compare it to the oxygen abundance available to form water in situ. In this thesis, for the first time, a systematic rotation diagram analysis has been applied to infrared water emission. This analysis established a link between the spread of the rotational scatter and the water abundance in the inner disk, where a large rotational scatter would provide evidence for the migration scenario. Large rotational scatters are indeed tentatively observed in some disks, supporting water vapor enrichment from evaporation of icy migrators. Future higher-resolution observations will provide important answers on the origin of water vapor and its connection to disk evolution and planet formation processes.

Banzatti, Andrea

2013-03-01

356

Droplet Vaporization in a Supercritical Microgravity Environment  

NASA Technical Reports Server (NTRS)

A model is presented which describes single liquid droplet vaporization at nearly critical liquid pressures and temperatures. A modified Redlich-Kwong equation of state is used to evaluate the fugacities and liquid and vapor mole fractions at the interface under the assumption of interface equilibrium. Results obtained for different droplet sizes and conditions indicate significant differences in behavior in comparison with low-pressure quasi-steady droplet vaporization.

Curtis, E. W.; Farrell, P. V.

1987-01-01

357

Vapor pressure and thermodynamics of actinide metals  

Microsoft Academic Search

Precise vapor pressure measurements by target collection\\/mass spectrometric Knudsen effusion techniques were combined with crystal entropy estimates to produce self-consistent free-enrgy functions, permitting calculation of heats, entropies and free energies from 298°K to the highest temperatures of measurement. The vapor pressures and thermodyamics of vaporization of americium, curium, berkelium, and californium are compared in terms of electronic structure and bonding

J. W. Ward; P. D. Kleinschmidt; R. G. Haire; D. Brown

1980-01-01

358

Coupling apparatus for a metal vapor laser  

DOEpatents

Coupling apparatus for a large bore metal vapor laser is disclosed. The coupling apparatus provides for coupling high voltage pulses (approximately 40 KV) to a metal vapor laser with a high repetition rate (approximately 5 KHz). The coupling apparatus utilizes existing thyratron circuits and provides suitable power input to a large bore metal vapor laser while maintaining satisfactory operating lifetimes for the existing thyratron circuits.

Ball, Don G. (Livermore, CA); Miller, John L. (Dublin, CA)

1993-01-01

359

Uptake of Mercury Vapor by Wheat  

PubMed Central

Using a whole-plant chamber and 203Hg-labeled mercury, a quantitative study was made of the effect of environmental parameters on the uptake, by wheat (Triticum aestivum), of metallic mercury vapor, an atmospheric pollutant. Factors were examined in relation to their influence on components of the gas-assimilation model, [Formula: see text] where U(Hg) is the rate of mercury uptake per unit leaf surface, Ca? is the ambient mercury vapor concentration, Cl? is the mercury concentration at immobilization sites within the plant (assumed to be zero), rl.Hg is the total leaf resistance to mercury vapor exchange, and rm.hg is a residual term to account for unexplained physical and biochemical resistances to mercury vapor uptake. Essentially all mercury vapor uptake was confined to the leaves. rl.hg was particularly influenced by illumination (0 to 12.8 klux), but unaffected by ambient temperature (17 to 33 C) and mercury vapor concentration (0 to 40 ?g m?3). The principal limitation to mercury vapor uptake was rm.hg, which was linearly related to leaf temperature, but unaffected by mercury vapor concentration and illumination, except for apparent high values in darkness. Knowing Ca? and estimating rl.hg and rm.hg from experimental data, mercury vapor uptake by wheat in light was accurately predicted for several durations of exposure using the above model.

Browne, Christopher L.; Fang, Sheng C.

1978-01-01

360

Ambient air heated electrically assisted cryogen vaporizer  

SciTech Connect

A high volume cryogen vaporizer includes a radiator where a working fluid draws heat from ambient air for vaporizing a cryogen in a heat exchanger. An electrical heater is provided for periodically heating the working fluid to defrost the radiator, thereby allowing sustained operation of the vaporizer. When not required for defrosting the radiator, the heater may be operated to heat a working fluid in a circuit separate from that of the radiator, and in which the heated working fluid is used for further elevating the temperature of the vaporized cryogen in a second heat exchanger, thereby making possible a gas output temperature higher than ambient air temperature.

Brigham, W. D.; Dung, N. D.

1985-05-28

361

Water vapor trends over Boulder, Colorado  

NASA Astrophysics Data System (ADS)

Water vapor in the atmosphere is responsible for a significant portion of the greenhouse effect, and even small changes in the upper troposphere or lower stratosphere can have a large effect on climate. A new analysis of water vapor measurements by balloon-borne frost point hygrometers over Boulder, Colo., shows that stratospheric water vapor has increased over the past 30 years. Hurst et al. broke the long measurement record into four discrete time periods and determined the water vapor trends in each period for five 2-kilometer-thick stratospheric layers (16-26 kilometers in altitude). The scientists found that, on average, stratospheric water vapor increased by about 1 part per million by volume (27%) over the past 30 years, though there were many shorter-term variations in the record. Water vapor levels increased during 1980-1989 and 1990-2000, decreased from 2001 to 2005, and then increased again after 2005. The authors found that, at most, 30% of the observed water vapor increases can be attributed to greater amounts of methane oxidation in the stratosphere. The 2001-2005 decrease in midlatitude water vapor has been linked to observations of anomalously low tropopause temperatures in the tropics, but, to date, no connection between the observed water vapor increases and tropical tropopause temperatures has been found despite ongoing efforts. (Journal of Geophysical Research-Atmospheres, doi:10.1029/2010JD015065, 2011)

Tretkoff, Ernie

2011-04-01

362

Metal Vapor Condensation under High Pressure (Mercury Vapor to 500 Psia).  

National Technical Information Service (NTIS)

Mercury vapor up to 500 psia was condensed outside a cylindrical tube in both horizontal and vertical positions. Results show consistently low heat transfer coefficients compared to Nusselt's theory. Two auxiliary mercury vapor condensers downstream of th...

S. Hsieh C. F. Bonilla

1975-01-01

363

Water vapor, whence comest thou.  

NASA Technical Reports Server (NTRS)

During a 14-hour period on Mar. 7, 1971, the Apollo 14 ALSEP suprathermal ion detector experiment (SIDE) observed an intense, prolonged series of bursts of 48.6-eV ions at the lunar surface. The SIDE mass analyzer showed the mass per unit charge of these ions to be characteristic of water vapor if singly ionized. The event was also observed by the SIDE total ion detectors (TIDs) at the Apollo 14 site and at Apollo 12 (located 183 km to the west). The TID data from SIDE 14 indicate that the energy spectrum was narrower than the 20-eV interval between energy channels. Ion spectra due to the LM exhaust gases are shown to be readily identified by the SIDE and are distinctly different in character from the spectra obtained on March 7. Detailed consideration of other possible sources of water, including the Apollo 14 CSM, leads to the conclusion that the water vapor did not come from a man-made source. Also, it is estimated that the event may have involved a quantity of water much greater than that which has been artificially introduced into the lunar environment. Consequently, it appears to be of lunar origin.

Freeman, J. W., Jr.; Hills, H. K.; Vondrak, R. R.

1972-01-01

364

Synthesis of silicon carbide nanotubes by chemical vapor deposition.  

PubMed

Silicon carbide nanotubes (SiCNTs) were directly synthesized by chemical vapor deposition (CVD) in the paper. Methyltrichlorosilane (MTS) was selected as the SiC gaseous source and, ferrocence and thiophene as the catalyst and the cocatalyst, respectively. The influences of reaction temperature, contents of catalyst and cocatalyst, and content of gaseous source on the morphologies of the products were investigated, respectively. The products were identified by high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX), respectively. The synthesis of SiCNTs by CVD suggested a condition-dependent process. Novel SiCNTs, with 20 approximately 80 nm in outer diameter and 15 approximately 35 nm in inner diameter, respectively, were observed. The wall structure similar to that of carbon nanotubes was not found for the SiCNTs. PMID:17450808

Xie, Zhengfang; Tao, Deliang; Wang, Jiqing

2007-02-01

365

Vapor Phase Transport Synthesis of Zeolites from Sol-Gel Precursors  

SciTech Connect

A study of zeolite crystallization from sol-gel precursors using the vapor phase transport synthesis method has been performed. Zeolites (ZSM-5, ZSM-48, Zeolite P, and Sodalite) were crystallized by contacting vapor phase organic or organic-water mixtures with dried sodium silicate and dried sodium alumino-silicate gels. For each precursor gel, a ternary phase system of vapor phase organic reactant molecules was explored. The vapor phase reactant mixtures ranged from pure ethylene diamene, triethylamine, or water, to an equimolar mixture of each. In addition, a series of gels with varied physical and chemical properties were crystallized using the same vapor phase solvent mixture for each gel. The precursor gels and the crystalline products were analyzed via Scanning Electron Microscopy, Electron Dispersive Spectroscopy, X-ray mapping, X-ray powder diffraction, nitrogen surface area, Fourier Transform Infrared Spectroscopy, and thermal analyses. The product phase and purity as a function of the solvent mixture, precursor gel structure, and precursor gel chemistry is discussed.

THOMA,STEVEN G.; NENOFF,TINA M.

2000-07-14

366

THE BACTERICIDAL ACTION OF PROPYLENE GLYCOL VAPOR ON MICROORGANISMS SUSPENDED IN AIR. I  

PubMed Central

It has been found that propylene glycol vapor dispersed into the air of an enclosed space produces a marked and rapid bactericidal effect on microorganisms introduced into such an atmosphere in droplet form. Concentrations of 1 gm. of propylene glycol vapor in two to four million cc. of air produced immediate and complete sterilization of air into which pneumococci, streptococci, staphylococci, H. influenzae, and other microorganisms as well as influenza virus had been sprayed. With lesser concentrations of propylene glycol, rapid and marked reduction in the number of air-borne bacteria occurred, but complete sterilization of the air required a certain interval of time. Pronounced effects on both pneumococci and hemolytic streptococci were observed when concentrations as low as 1 gm. of glycol to fifty million cc. of air were employed. Numerous control tests showed that failure of the glycol-treated microorganisms to grow on the agar plates was due to actual death of the bacteria. The means by which propylene glycol vapor produces its effect on droplet-borne bacteria is discussed and data relating the bactericidal properties of propylene glycol in vitro to the lethal action of its vapor is presented. Atmospheres containing propylene glycol vapor are invisible, odorless, and non-irritating. This glycol is essentially non-toxic when given orally and intravenously. Tests on possible deleterious effects of breathing propylene glycol containing atmospheres over long periods of time are being carried out.

Robertson, O. H.; Bigg, Edward; Puck, Theodore T.; Miller, Benjamin F.

1942-01-01

367

75 FR 48593 - Pipeline Safety: Periodic Updates of Regulatory References to Technical Standards and...  

Federal Register 2010, 2011, 2012, 2013

...Liquefied Natural Gas (LNG...dispersion analyses for vapor...Welding of Pipelines and Related...preliminary analysis. [[Page...Transporting gas affects the...Natural Gas, Pipeline safety. 49...review and analysis of leak repair...and the pipeline environment...Subpart O-Gas...

2010-08-11

368

Multiple overseas dispersal in amphibians  

Microsoft Academic Search

Amphibians are thought to be unable to disperse over ocean barriers because they do not tolerate the osmotic stress of salt water. Their distribution patterns have therefore generally been explained by vicari- ance biogeography. Here, we present compelling evidence for overseas dispersal of frogs in the Indian Ocean region based on the discovery of two endemic species on Mayotte. This

Miguel Vences; D. Rodriguez Vieites; Frank Glaw; Henner Brinkmann; Joachim Kosuch; Michael Veith; Axel Meyer

2003-01-01

369

Solitons and polarization mode dispersion.  

PubMed

Analytical expressions are presented for Manakov solitons perturbed by polarization mode dispersion (PMD). Comparison is made with computer simulations. Dispersion-managed solitons are also studied. It is concluded that at high bit rates solitons are superior to linear return-to-zero propagation with regard to PMD. PMID:18059857

Chen, Y; Haus, H A

2000-03-01

370

Dispersal of Anoplophora glabripennis (Cerambycidae)  

Microsoft Academic Search

Asa bas isfor the development of both eradication and management s trategiesfor control of Anoplophora glabripennis Motschulsky (Asian longhorned beetle) investigations of A. glabripennis dispersal were undertaken in Gansu Province, China, in 1999. Data analysis of the Þrst year study of population dispersal, in which 16,000 adult A. glabripennis were marked and released (mass-mark recapture method), has shown that the

Michael T. Smith; Jay Bancroft; Guohong Li; Ruitong Gao; Stephen Teale

2001-01-01

371

Preparation of alkali metal dispersions  

NASA Technical Reports Server (NTRS)

A method is described for producing alkali metal dispersions of high purity. The dispersions are prepared by varying the equilibrium solubility of the alkali metal in a suitable organic solvent in the presence of aromatic hydrocarbons. The equilibrium variation is produced by temperature change. The size of the particles is controlled by controlling the rate of temperature change.

Rembaum, A.; Landel, R. F. (inventors)

1968-01-01

372

Procedure for dispersing fiber bundles  

NASA Technical Reports Server (NTRS)

Fiber bundles are dispersed and fibers are cleaned within enclosed container; therefore, safety clothing, masks, and eye protection are not required. Procedure also could be used wherever materials, such as fiberglass or insulation, require dispersion, fluffing, or cleaning. Process could be automated into continuous operation for handling large quantities of fiber.

Padilla, D.

1974-01-01

373

Near real time vapor detection and enhancement using aerosol adsorption  

DOEpatents

A vapor sample detection method where the vapor sample contains vapor and ambient air and surrounding natural background particles. The vapor sample detection method includes the steps of generating a supply of aerosol that have a particular effective median particle size, mixing the aerosol with the vapor sample forming aerosol and adsorbed vapor suspended in an air stream, impacting the suspended aerosol and adsorbed vapor upon a reflecting element, alternatively directing infrared light to the impacted aerosol and adsorbed vapor, detecting and analyzing the alternatively directed infrared light in essentially real time using a spectrometer and a microcomputer and identifying the vapor sample.

Novick, Vincent J. (Downers Grove, IL); Johnson, Stanley A. (Countryside, IL)

1999-01-01

374

Near real time vapor detection and enhancement using aerosol adsorption  

DOEpatents

A vapor sample detection method is described where the vapor sample contains vapor and ambient air and surrounding natural background particles. The vapor sample detection method includes the steps of generating a supply of aerosol that have a particular effective median particle size, mixing the aerosol with the vapor sample forming aerosol and adsorbed vapor suspended in an air stream, impacting the suspended aerosol and adsorbed vapor upon a reflecting element, alternatively directing infrared light to the impacted aerosol and adsorbed vapor, detecting and analyzing the alternatively directed infrared light in essentially real time using a spectrometer and a microcomputer and identifying the vapor sample. 13 figs.

Novick, V.J.; Johnson, S.A.

1999-08-03

375

G-Band Vapor Radiometer Precipitable Water Vapor (GVRPWV) Value-Added Product  

SciTech Connect

The G-Band Vapor Radiometer Precipitable Water Vapor (GVRPWV) value-added product (VAP) computes precipitable water vapor using neural network techniques from data measured by the GVR. The GVR reports time-series measurements of brightness temperatures for four channels located at 183.3 ± 1, 3, 7, and 14 GHz.

Koontz, A; Cadeddu, M

2012-12-05

376

Disperser seal and method  

SciTech Connect

A seal is described for a shaft of a disperser crusher, that pulverizes hot coal particles, maintains a higher than atmospheric pressure within a casing for the crusher, and is able to withstand elevated temperatures that are produced within the casing. The pressure and temperature result from hot gases that convey coal particles to the crusher. The seal includes self lubricating graphite packings that are urged in abutting relation with a smooth, ceramic sleeve on the shaft and are able to withstand the temperature on the shaft surface. A first, interior packing is on the inside of a wall of the casing while a second, exterior packing is outside of the wall. Superheated steam, a gas inert with the coal particles, is supplied to the interior packing with sufficient pressure to substantially prevent the migration of coal particles through the interior packing. The tendency of the coal particles to migrate from the container through the interior packing is further inhibited by providing a tortuous path from the casing to the interior packing.

Johnston, R. T.

1981-06-02

377

Modeling volcanic ash dispersal  

SciTech Connect

Explosive volcanic eruptions inject into the atmosphere large amounts of volcanic material (ash, blocks and lapilli). Blocks and larger lapilli follow ballistic and non-ballistic trajectories and fall rapidly close to the volcano. In contrast, very fine ashes can remain entrapped in the atmosphere for months to years, and may affect the global climate in the case of large eruptions. Particles having sizes between these two end-members remain airborne from hours to days and can cover wide areas downwind. Such volcanic fallout entails a serious threat to aircraft safety and can create many undesirable effects to the communities located around the volcano. The assessment of volcanic fallout hazard is an important scientific, economic, and political issue, especially in densely populated areas. From a scientific point of view, considerable progress has been made during the last two decades through the use of increasingly powerful computational models and capabilities. Nowadays, models are used to quantify hazard scenarios and/or to give short-term forecasts during emergency situations. This talk will be focused on the main aspects related to modeling volcanic ash dispersal and fallout with application to the well known problem created by the Eyjafjöll volcano in Iceland. Moreover, a short description of the main volcanic monitoring techniques is presented.

None

2010-10-22

378

Hybrid Dispersion Laser Scanner  

NASA Astrophysics Data System (ADS)

Laser scanning technology is one of the most integral parts of today's scientific research, manufacturing, defense, and biomedicine. In many applications, high-speed scanning capability is essential for scanning a large area in a short time and multi-dimensional sensing of moving objects and dynamical processes with fine temporal resolution. Unfortunately, conventional laser scanners are often too slow, resulting in limited precision and utility. Here we present a new type of laser scanner that offers ~1,000 times higher scan rates than conventional state-of-the-art scanners. This method employs spatial dispersion of temporally stretched broadband optical pulses onto the target, enabling inertia-free laser scans at unprecedented scan rates of nearly 100 MHz at 800 nm. To show our scanner's broad utility, we use it to demonstrate unique and previously difficult-to-achieve capabilities in imaging, surface vibrometry, and flow cytometry at a record 2D raster scan rate of more than 100 kHz with 27,000 resolvable points.

Goda, K.; Mahjoubfar, A.; Wang, C.; Fard, A.; Adam, J.; Gossett, D. R.; Ayazi, A.; Sollier, E.; Malik, O.; Chen, E.; Liu, Y.; Brown, R.; Sarkhosh, N.; di Carlo, D.; Jalali, B.

2012-06-01

379

Hybrid Dispersion Laser Scanner  

PubMed Central

Laser scanning technology is one of the most integral parts of today's scientific research, manufacturing, defense, and biomedicine. In many applications, high-speed scanning capability is essential for scanning a large area in a short time and multi-dimensional sensing of moving objects and dynamical processes with fine temporal resolution. Unfortunately, conventional laser scanners are often too slow, resulting in limited precision and utility. Here we present a new type of laser scanner that offers ?1,000 times higher scan rates than conventional state-of-the-art scanners. This method employs spatial dispersion of temporally stretched broadband optical pulses onto the target, enabling inertia-free laser scans at unprecedented scan rates of nearly 100?MHz at 800?nm. To show our scanner's broad utility, we use it to demonstrate unique and previously difficult-to-achieve capabilities in imaging, surface vibrometry, and flow cytometry at a record 2D raster scan rate of more than 100?kHz with 27,000 resolvable points.

Goda, K.; Mahjoubfar, A.; Wang, C.; Fard, A.; Adam, J.; Gossett, D. R.; Ayazi, A.; Sollier, E.; Malik, O.; Chen, E.; Liu, Y.; Brown, R.; Sarkhosh, N.; Di Carlo, D.; Jalali, B.

2012-01-01

380

Modeling volcanic ash dispersal  

ScienceCinema

Explosive volcanic eruptions inject into the atmosphere large amounts of volcanic material (ash, blocks and lapilli). Blocks and larger lapilli follow ballistic and non-ballistic trajectories and fall rapidly close to the volcano. In contrast, very fine ashes can remain entrapped in the atmosphere for months to years, and may affect the global climate in the case of large eruptions. Particles having sizes between these two end-members remain airborne from hours to days and can cover wide areas downwind. Such volcanic fallout entails a serious threat to aircraft safety and can create many undesirable effects to the communities located around the volcano. The assessment of volcanic fallout hazard is an important scientific, economic, and political issue, especially in densely populated areas. From a scientific point of view, considerable progress has been made during the last two decades through the use of increasingly powerful computational models and capabilities. Nowadays, models are used to quantify hazard scenarios and/or to give short-term forecasts during emergency situations. This talk will be focused on the main aspects related to modeling volcanic ash dispersal and fallout with application to the well known problem created by the Eyjafjöll volcano in Iceland. Moreover, a short description of the main volcanic monitoring techniques is presented.

None

2011-10-06

381

Hybrid dispersion laser scanner.  

PubMed

Laser scanning technology is one of the most integral parts of today's scientific research, manufacturing, defense, and biomedicine. In many applications, high-speed scanning capability is essential for scanning a large area in a short time and multi-dimensional sensing of moving objects and dynamical processes with fine temporal resolution. Unfortunately, conventional laser scanners are often too slow, resulting in limited precision and utility. Here we present a new type of laser scanner that offers ?1,000 times higher scan rates than conventional state-of-the-art scanners. This method employs spatial dispersion of temporally stretched broadband optical pulses onto the target, enabling inertia-free laser scans at unprecedented scan rates of nearly 100?MHz at 800?nm. To show our scanner's broad utility, we use it to demonstrate unique and previously difficult-to-achieve capabilities in imaging, surface vibrometry, and flow cytometry at a record 2D raster scan rate of more than 100?kHz with 27,000 resolvable points. PMID:22685627

Goda, K; Mahjoubfar, A; Wang, C; Fard, A; Adam, J; Gossett, D R; Ayazi, A; Sollier, E; Malik, O; Chen, E; Liu, Y; Brown, R; Sarkhosh, N; Di Carlo, D; Jalali, B

2012-01-01

382

An Eulerian Lagrangian simulation of the dispersed flow film boiling regime during reflood including the spacer grid effects  

Microsoft Academic Search

The objective of this research is to develop a realistic model for the fluid field of the complicated dispersed flow regime during the reflood phase after a LOCA. For this modeling, we use a new Eulerian - Lagrangian approach and introduce the effects of spacer grids. All paths of energy transfer between vapor, droplets, rods, and grid spacers have been

Ami Yerachmiel Nagler

2000-01-01

383

Well-Dispersed Single Walled Carbon Nanotube Growth from Iron Nanoparticles Created from Poly(styrene-b-ethylmethylferrocenylsilane) Thin Films  

Microsoft Academic Search

Well dispersed single walled carbon nanotubes (SWNTs) have been grown directly from a diblock copolymer thin film, poly(styrene-b-ethylmethylferrocenylsilane), determined to be random spheres of polyethylmethylferrocenylsilane (PEMFS) in polystyrene (PS). When the spin cast block copolymer was heated in a chemical vapor deposition oven (CVD), iron nanoparticles formed from the ferrocene containing polymer block, acting as metal catalysts for SWNT growth.

Sarah Lastella; Yung Joon Jung; Hoichang Yang; Robert Vajtai; Pulickel Ajayan; Chang Ryu; David Rider; Ian Manners

2004-01-01

384

Observe animated satellite images of water vapor  

NSDL National Science Digital Library

This Flash animation points out water vapor content 6-10 km above Earth's surface measured by infrared sensors on satellites. Lighter areas represent high moisture content, darker areas, little water vapor. Jet streams are viewed as elongated dark regions bordered by lighter sections.

Goes; Noaa; Earth, Exploring

385

Cell for electrolysis of water vapor  

NASA Technical Reports Server (NTRS)

Electrolytic cells regenerate oxygen from the water vapor in the air of closed-loop life-support system and remove water vapor from air circulated through them. Water is converted into oxygen and hydrogen; the oxygen is returned to the air, the hydrogen is vented or used elsewhere.

Celino, V. A.; Roebelen, G.

1972-01-01

386

Quantitative organic vapor-particle sampler  

DOEpatents

A quantitative organic vapor-particle sampler for sampling semi-volatile organic gases and particulate components. A semi-volatile organic reversible gas sorbent macroreticular resin agglomerates of randomly packed microspheres with the continuous porous structure of particles ranging in size between 0.05-10 .mu.m for use in an integrated diffusion vapor-particle sampler.

Gundel, Lara (Berkeley, CA); Daisey, Joan M. (Walnut Creek, CA); Stevens, Robert K. (Cary, NC)

1998-01-01

387

Surface adsorption and retention of TNT vapors  

Microsoft Academic Search

A relatively inexpensive and reliable method was developed to generate vapor pulses of explosives using 2,4,6 trinitrotoluene (TNT) for proof of concept. The technology developed in vapor generation and collection was integrated with ion mobility spectrometry (IMS) as the primary analytical tool, keeping in mind utility in field scenarios. The use of the technology was demonstrated in evaluating different surfaces

Edward J. Poziomek; Saeed H. Almeer

1998-01-01

388

ON-LINE CALCULATOR: VAPOR INTRUSION MODELING  

EPA Science Inventory

Migration of volatile chemicals from the subsurface into overlying buildings is called vapor intrusion (VI). Volatile organic chemicals in contaminated soils or groundwater can emit vapors, which may migrate through subsurface soils and may enter the indoor air of overlying build...

389

High bandwidth vapor density diagnostic system  

DOEpatents

A high bandwidth vapor density diagnostic system for measuring the density of an atomic vapor during one or more photoionization events. The system translates the measurements from a low frequency region to a high frequency, relatively noise-free region in the spectrum to provide improved signal to noise ratio.

Globig, Michael A. (Antioch, CA); Story, Thomas W. (Oakley, CA)

1992-01-01

390

Infrared absorption of explosive molecule vapors  

Microsoft Academic Search

Infrared absorption spectra have been obtained for the high explosive molecules TNT, RDX, and PETN in the vapor phase. Integrated band strengths were measured for the symmetric and antisymmetric -NO2 vibrations in each of these molecules. Ab initio calculations of vibrational frequencies and intensities were carried out for comparison with the experimental data. Previous measurements of the heats of vaporization

James Janni; Brian D Gilbert; R. W Field; Jeffrey I Steinfeld

1997-01-01

391

Risk assessment of metal vapor arcing  

NASA Technical Reports Server (NTRS)

A method for assessing metal vapor arcing risk for a component is provided. The method comprises acquiring a current variable value associated with an operation of the component; comparing the current variable value with a threshold value for the variable; evaluating compared variable data to determine the metal vapor arcing risk in the component; and generating a risk assessment status for the component.

Hill, Monika C. (Inventor); Leidecker, Henning W. (Inventor)

2009-01-01

392

IN SITU SOIL VAPOR EXTRACTION TREATMENT  

EPA Science Inventory

Soil vapor extraction (SVE) is designed to physically remove volatile compounds, generally from the vadose or unsaturated zone. t is an in situ process employing vapor extraction wells alone or in combination with air injection wells. acuum blowers supply the motive force, induci...

393

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...

394

SOIL VAPOR EXTRACTION TECHNOLOGY: REFERENCE HANDBOOK  

EPA Science Inventory

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

395

Gasoline vapor recovery system and method  

Microsoft Academic Search

A gasoline vapor recovery system is described which is particularly adapted for bulk flow plants. The system includes an absorber into which raw gasoline vapor is introduced, as by a connection from a tank truck while the tank truck is loaded with gasoline. Light oil, such as kerosine, is pumped into the absorber and acts as a carrier, carrying the

A. J. Doncer; H. R. White

1975-01-01

396

Dynamics of Acoustically Vaporized Microdroplets  

NASA Astrophysics Data System (ADS)

A combined theoretical and computational approach is utilized to understand the bubble evolution dynamics resulting by vaporizing the superheated dodecafluoropentane (DDFP, C5F12) microdroplets via an acoustic perturbation. This work is inspired by a developmental gas embolotherapy technique for cancer treatment by infarcting tumors using selectively formed gas bubbles. The evolution process comprises of three regimes; an initial linear rapid spherical growth followed by a linear compressed oval shaped growth and finally a slow asymptotic non-linear spherical growth. The bubble evolution process compares quite well with the ultra high-speed experiments. The final bubble radius scales linearly with the initial droplet radius and is approximately five times the initial droplet radius. A pressure pulse with amplitude approximately twice as that of ambient conditions is observed. The pressure pulse wavelength increases with an increasing droplet size whereas the pulse amplitude is weakly dependent on droplet size. This work is supported by NIH grant R01EB006476.

Qamar, Adnan; Wong, Zheng Zheng; Fowlkes, J. Brian; Bull, Joseph

2010-11-01

397

Tungsten chemical vapor deposition method  

SciTech Connect

A tungsten chemical vapor deposition method is described, comprising: a first step of selectively growing a first thin tungsten film of a predetermined thickness in a desired region on the surface of a silicon substrate by reduction of a WF[sub 6] gas introduced into an atmosphere of a predetermined temperature containing said silicon substrate; and a second step of selectively growing a second tungsten film of a predetermined thickness on said first thin tungsten film by reduction of said WF[sub 6] with a silane gas further introduced into said atmosphere, wherein the surface state of said substrate is monitored by a pyrometer and the switching from said first step to said second step is performed when the emissivity of infrared light from the substrate surfaces reaches a predetermined value.

Hirano, Kiichi; Takeda, Nobuo.

1993-07-13

398

Does Air Contain Water Vapor?  

NSDL National Science Digital Library

In this activity, students monitor the change that takes place when water vapor condenses from a gas to a liquid and see how a change in temperature affects this transformation. Materials needed to conduct the investigation include two thermometers, a clear glass container, ice cubes and tap water. The resource includes background information, teaching tips and questions to guide student discussion. This is chapter 10 of Meteorology: An Educator's Resource for Inquiry-Based Learning for Grades 5-9. The guide includes a discussion of learning science, the use of inquiry in the classroom, instructions for making simple weather instruments, and more than 20 weather investigations ranging from teacher-centered to guided and open inquiry investigations.

399

Spin relaxation in alkali vapors  

NASA Astrophysics Data System (ADS)

In this dissertation, I describe a series of experimental and theoretical studies directed toward the understanding of spin-relaxation mechanisms in an alkali vapor. I present a large volume of new data that allows prediction of spin-relaxation rates under a wider variety of circumstances than was possible before. These results can be described by a model consisting of four relaxation mechanisms: relaxation on the vessel walls, in collisions with a buffer gas, in alkali singlet dimers, and what I refer to as alkali-alkali relaxation. The latter half of this work is devoted to a search for a theoretical model of alkali-alkali relaxation. I show that the previously held belief that alkali-alkali relaxation occurs during binary alkali collisions cannot be reconciled with the data presented here, and discuss possible alternate theories. Finally, I suggest that relaxation in metastable alkali trimer complexes may be the microscopic mechanism best able to explain these new results.

Kadlecek, Stephen John

1999-11-01

400

Confined zone dispersion flue gas desulfurization demonstration  

SciTech Connect

The CZD process involves flue gas post-treatment, physically located between a boiler's outlet and its particulate collector, which in the majority of cases is an electrostatic precipitator. The features that distinguish this process from other similar injection processes are: Injection of an alkaline slurry directly into the duct, instead of injection of dry solids into the duct ahead of a fabric filter. Use of an ultrafine calcium/magnesium hydroxide, type S pressure-hydrated dolomitic lime. This commercial product is made from plentiful, naturally occurring dolomite. Low residence time, made possibly by the high effective surface area of the type S lime. Localized dispersion of the reagent. Slurry droplets contact only part of the gas while the droplets are drying, to remove up to 50 percent of the SO{sub 2} and significant amounts of NO{sub x}. The process uses dual fluid rather than rotary atomizers. Improved ESP performance via gas conditioning from the increased water vapor content, and lower temperatures. Supplemental conditioning with SO{sub 3} is not believed necessary for satisfactory removal of particulate matter. The waste product is composed of magnesium and calcium sulfite and sulfate, with some excess lime. This product mixed with fly ash is self-stabilizing because of the excess lime values, and thus tends to retain heavy metals in insoluble forms within the fly ash.

Not Available

1991-09-05

401

Condensation coefficient of methanol vapor near vapor-liquid equilibrium states  

NASA Astrophysics Data System (ADS)

This paper is concerned with the nonequilibrium condensation from a vapor to a liquid phase on the plate endwall of a shock tube behind a reflected shock wave. The growth of a liquid film on the endwall is measured by an optical interferometer using a laser beam. The experiment is carefully conducted on the precisely designed apparatus, and thereby the condensation coefficient of methanol vapor is determined in a wide range of vapor-liquid conditions from near to far from equilibrium states. The result shows that the condensation coefficient increases with the increase of the ratio of number densities of vapor and saturated vapor at the interface.

Fujikawa, S.; Yano, T.; Ichijo, M.; Iwanami, K.

402

Thermal Plasma Chemical Vapor Deposition  

NASA Astrophysics Data System (ADS)

Diamond has many unrivaled properties and has great application potentials in modern industry. Among various metastable chemical vapor deposition methods for producing diamond, thermal plasma chemical vapor deposition has shown advantages of offering high growth rates and high quality. However, systematic parametric studies are needed for optimization of the process. This study investigates the effects of substrate materials, substrate temperatures, substrate pre-treatment methods, precursor concentrations, and process pressures on the initial nucleation, growth rate, morphology, and quality of the diamond films under thermal plasma conditions. X-ray diffraction, optical microscopy, scanning electron microscopy, and Raman spectroscopy have been used for the diamond film characterization. Thermal plasmas have been also used to deposit homoepitaxial diamond films at high growth rates. High quality macro-sized diamond crystals have been grown on {100} and {110} oriented natural type IIa diamond seeds. Raman spectra reveal that the diamond deposit is of high quality. Laue X-ray diffraction patterns show that the diamond grown on the seed is single crystal and oriented epitaxially with the underlying seed crystal. The gas phase chemistry has been calculated using computer code SOLGASMIX to determine the equilibrium gaseous composition in thermal plasmas. Key species concentrations have been obtained under various pressure conditions. Although kinetic factors have not been taken into account, equilibrium conditions offer an estimation of the process justified by the "frozen chemistry" associated with the fast quenching in the boundary layer. Due to the strong emission of the highly luminous plasma plumes, it has been difficult to measure the in -situ substrate temperature distribution with conventional infrared optical pyrometers. A new technique has been developed to obtain the surface temperature distribution of the substrate by combining the experimental temperature measurements of an array of thermocouples imbedded in the substrate and analytical solutions of the two-dimensional heat conduction equation. This method enables an indirect determination of the substrate temperature distribution.

Lu, Zhipeng

403

Bhopal atmospheric dispersion revisited.  

PubMed

There is a vital need to understand details of the methylisocyanate (MIC) release that occurred at the 1984 Union Carbide Ltd. pesticide plant in Bhopal, India in order to avoid or respond to such releases in the future. However, we believe there are serious deficiencies in currently available dispersion predictions of the impact of toxic materials on humans and animals downwind of the plant. Specifically, cloud densities have been underestimated due to failure to account for the presence of a liquid/solid aerosol that would have been produced by the chemical reactions that caused the problem. Using data reported in Union Carbide's own investigation of the accident, which included chemical reaction data, we estimated aerosol compositions and cloud densities, then modeled the Bhopal release, simulating potential exposure levels at various locations under a number of wind-condition scenarios. For the worst-case (low wind speed and high aerosol densities), our predicted MIC concentrations at ground level are at least one order of magnitude greater than any previously published estimates. The centerline elevation of the jetting plume released at 33 m elevation is predicted to rise to about 41 m before falling, resulting in a 40 ppm (Immediately Dangerous to Life or Health, IDLH) concentration contour that reaches the ground at about 410 m downwind of the release location. This is consistent with observations that the plant environs were not hard-hit while the public immediately downwind of the plant perimeter was severely exposed. Concentrations on the order of 1000 ppm are predicted at some ground-level locations, which are more consistent than previous estimates with the reported large numbers of deaths and injuries of humans and animals. PMID:22819479

Havens, Jerry; Walker, Heather; Spicer, Tom

2012-09-30

404

Migration of dispersive GPR data  

USGS Publications Warehouse

Electrical conductivity and dielectric and magnetic relaxation phenomena cause electromagnetic propagation to be dispersive in earth materials. Both velocity and attenuation may vary with frequency, depending on the frequency content of the propagating energy and the nature of the relaxation phenomena. A minor amount of velocity dispersion is associated with high attenuation. For this reason, measuring effects of velocity dispersion in ground penetrating radar (GPR) data is difficult. With a dispersive forward model, GPR responses to propagation through materials with known frequency-dependent properties have been created. These responses are used as test data for migration algorithms that have been modified to handle specific aspects of dispersive media. When either Stolt or Gazdag migration methods are modified to correct for just velocity dispersion, the results are little changed from standard migration. For nondispersive propagating wavefield data, like deep seismic, ensuring correct phase summation in a migration algorithm is more important than correctly handling amplitude. However, the results of migrating model responses to dispersive media with modified algorithms indicate that, in this case, correcting for frequency-dependent amplitude loss has a much greater effect on the result than correcting for proper phase summation. A modified migration is only effective when it includes attenuation recovery, performing deconvolution and migration simultaneously.

Powers, M. H.; Oden, C. P.

2004-01-01

405

Effect of heat treatment on structure and properties of dispersed-type dental amalgam.  

PubMed

Effect of heat treatment of Ag-Cu-Pd dispersant particles on the structure, mechanical properties and mercury vapor release rate of an Ag-Cu-Sn/Ag-Cu-Pd-based dental amalgam has been investigated. Experimental results indicate that crystallinity of dispersant Ag-Cu-Pd alloy increases with increasing HTT, with most notable increase occurring between 100 and 200 degrees C. Increasing HTT of Ag-Cu-Pd alloy does not change much of the mercury/alloy ratio for amalgamation, but largely reduces working/setting time of the amalgam. The Ag-Cu-Pd particles in 7 d-aged amalgam are comprised primarily of an outer Sn/Cu/Pd-rich zone and an inner Ag/Cu/Pd-rich zone with eutectic-type morphology and chemical distribution. The annealing-enhanced Pd segregation effect is most significantly observed in the amalgam derived from 300 degrees C-annealed Ag-Cu-Pd dispersant. This amalgam also has the highest compressive strength, highest DTS, and lowest creep rate. Higher annealing temperature causes mechanical property of the amalgam to deteriorate. The initial mercury vapor release rates of amalgams derived from 100, 200 and 300 degrees C-annealed Ag-Cu-Pd dispersant are significantly lower than that derived from 400 degrees C-annealed dispersant. PMID:17577640

Ju, Chien-Ping; Chen, Yu-Hsuan; Ho, Wen-Fu; Ho, Shu-Ching; Chen, Wen-Cheng; Shieh, Dar-Bin; Chern Lin, Jiin-Huey

2008-01-01

406

The impact of vaporized nanoemulsions on ultrasound-mediated ablation  

PubMed Central

Background The clinical feasibility of using high-intensity focused ultrasound (HIFU) for ablation of solid tumors is limited by the high acoustic pressures and long treatment times required. The presence of microbubbles during sonication can increase the absorption of acoustic energy and accelerate heating. However, formation of microbubbles within the tumor tissue remains a challenge. Phase-shift nanoemulsions (PSNE) have been developed as a means for producing microbubbles within tumors. PSNE are emulsions of submicron-sized, lipid-coated, and liquid perfluorocarbon droplets that can be vaporized into microbubbles using short (<1 ms), high-amplitude (>5 MPa) acoustic pulses. In this study, the impact of vaporized phase-shift nanoemulsions on the time and acoustic power required for HIFU-mediated thermal lesion formation was investigated in vitro. Methods PSNE containing dodecafluoropentane were produced with narrow size distributions and mean diameters below 200 nm using a combination of sonication and extrusion. PSNE was dispersed in albumin-containing polyacrylamide gel phantoms for experimental tests. Albumin denatures and becomes opaque at temperatures above 58°C, enabling visual detection of lesions formed from denatured albumin. PSNE were vaporized using a 30-cycle, 3.2-MHz, at an acoustic power of 6.4 W (free-field intensity of 4,586 W/cm2) pulse from a single-element, focused high-power transducer. The vaporization pulse was immediately followed by a 15-s continuous wave, 3.2-MHz signal to induce ultrasound-mediated heating. Control experiments were conducted using an identical procedure without the vaporization pulse. Lesion formation was detected by acquiring video frames during sonication and post-processing the images for analysis. Broadband emissions from inertial cavitation (IC) were passively detected with a focused, 2-MHz transducer. Temperature measurements were acquired using a needle thermocouple. Results Bubbles formed at the HIFU focus via PSNE vaporization enhanced HIFU-mediated heating. Broadband emissions detected during HIFU exposure coincided in time with measured accelerated heating, which suggested that IC played an important role in bubble-enhanced heating. In the presence of bubbles, the acoustic power required for the formation of a 9-mm3 lesion was reduced by 72% and the exposure time required for the onset of albumin denaturation was significantly reduced (by 4 s), provided that the PSNE volume fraction in the polyacrylamide gel was at least 0.008%. Conclusions The time or acoustic power required for lesion formation in gel phantoms was dramatically reduced by vaporizing PSNE into bubbles. These results suggest that PSNE may improve the efficiency of HIFU-mediated thermal ablation of solid tumors; thus, further investigation is warranted to determine whether bubble-enhanced HIFU may potentially become a viable option for cancer therapy.

2013-01-01

407

Accumulating microparticles and direct-writing micropatterns using a continuous-wave laser-induced vapor bubble.  

PubMed

Through the enhanced photothermal effect, which was achieved using a silver film, a low power weakly focused continuous-wave laser (532 nm) was applied to create a vapor bubble. A convective flow was formed around the bubble. Microparticles dispersed in water were carried by the convective flow to the vapor bubble and accumulated on the silver film. By moving the laser spot, we easily manipulated the location of the bubble, allowing us to direct-write micropatterns on the silver film with accumulated particles. The reported simple controllable accumulation method can be applied to bimolecular detection, medical diagnosis, and other related biochip techniques. PMID:21956638

Zheng, Yajian; Liu, Hui; Wang, Yi; Zhu, Cong; Wang, Shuming; Cao, Jingxiao; Zhu, Shining

2011-11-21

408

Partial oxidation of methane on silica-supported silicomolybdic acid catalysts in an excess amount of water vapor  

SciTech Connect

Partial oxidation of methane into oxygenates such as methanol and formaldehyde on highly dispersed MoO{sub 3}/SiO{sub 2} catalysts was studied in an excess amount of water vapor. The reaction was carried out at 873 K using gases consisting of oxygen, methane, and water vapor. The selectivity of oxygenates was found to be a strong function of water vapor, and increased as the fraction of water vapor in a feed gas increased. Inversely, the selectivity of CO and CO{sub 2} in the products decreased as the fraction of water vapor increased. This is ascribed to the formation of silicomolybdic acid (SMA:H{sub 4}SiMo{sub 12}O{sub 40}) over the silica surface during the reaction, partially evidenced by IR measurements. Accordingly, silica-supported SMA catalysts were prepared and applied to the partial oxidation of methane under the same conditions as described above to see if SMA works as the active species for the reaction. Although SMA easily decomposed into SiO{sub 2} and MoO{sub 3} at 873 K without water vapor, it worked well for the production of oxygenates when the fraction of water vapor was more than 50% in the feed gas. The yield of oxygenates increased up to 20% of methane as the fraction of water vapor was around 60%; methane conversion was about 25% and the selectivity of oxygenates was 90%. In this paper, the authors will emphasize that SMA formed on the silica surface are the active species of silica-supported MoO{sub 3} catalysts for the partial oxidation of methane in an excess amount of water vapor.

Sugino, Tomomi; Kido, Ayako; Azuma, Naoto; Ueno, Akifumi; Udagawa, Yasuo

2000-02-15

409

Fractional reproduction-dispersal equations and heavy tail dispersal kernels.  

PubMed

Reproduction-Dispersal equations, called reaction-diffusion equations in the physics literature, model the growth and spreading of biological species. Integro-Difference equations were introduced to address the shortcomings of this model, since the dispersal of invasive species is often more widespread than what the classical RD model predicts. In this paper, we extend the RD model, replacing the classical second derivative dispersal term by a fractional derivative of order 1dispersal kernel. The general theory developed here accommodates a wide variety of infinitely divisible dispersal kernels that adapt to any scale. Each one corresponds to a generalised RD model with a different dispersal operator. The connection established here between RD and ID equations can also be exploited to generate convergent numerical solutions of RD equations along with explicit error bounds. PMID:17546475

Baeumer, Boris; Kovács, Mihály; Meerschaert, Mark M

2007-10-01

410

Photochemical fate of solvent constituents of Corexit oil dispersants.  

PubMed

In 2010, an estimated 1.87 million gallons (7079 cubic meters) of chemical dispersants were applied to open ocean waters in the Gulf of Mexico as part of the response to the Deepwater Horizon blowout. This unprecedented volume of dispersant application highlighted the importance of dispersant chemical formulations, raising questions of dispersant fate and transport in the open ocean and spurring research into formulation improvements. The research presented here elucidates the contribution of photolytic processes to the degradation of two solvent constituents of these dispersant mixtures: propylene glycol (PG) and 2-butoxyethanol (2-BE). A series of photodegradation experiments were conducted to determine the contribution of direct photolysis and indirect photolysis via hydroxyl radical (HO) to compound degradation. Experiments were performed using both deep UV light sources (low pressure (LP) and medium pressure (MP) mercury vapor ultraviolet (UV) lamps) and a solar simulator. Sample matrices included ultrapure water, nitrate amended water, hydrogen peroxide (H2O2) spiked water, Gulf of Mexico seawater, and a surface water from Boulder, CO. Experiments included determination of the molar absorption coefficients (?) and the HO reaction rate constants (kHO) of the individual compounds. Data illustrated that significant direct photolysis of either PG or 2-BE from sunlight is unlikely. The kHO for PG and 2-BE were determined to be 6.15 × 10(8) M(-1) s(-1) and 1.15 × 10(9) M(-1) s(-1), respectively. Solar simulation and UV experiments indicate that in natural systems, neither PG nor 2-BE is expected to undergo significant, rapid degradation due to direct or indirect photolysis. PG and 2-BE are effectively degraded through indirect photolysis in the presence of high HO concentrations, suggesting UV/H2O2 is a feasible possibility for the treatment of waters containing PG and 2-BE. PMID:24463172

Kover, Stephanie C; Rosario-Ortiz, Fernando L; Linden, Karl G

2014-04-01

411

Energy enhancement of dispersion managed soliton transmission system using mostly normal dispersion fiber  

Microsoft Academic Search

The dispersion managed soliton transmission system using mostly normal dispersion fiber is investigated. It is shown that, with the same net anomalous dispersion, the optimum energy enhancement is larger for the system using mostly normal dispersion fiber than the system using mostly anomalous dispersion fiber. The allowed transmission distance for the system using mostly normal dispersion fiber is longer than

Sien Chi; Jeng-Cherng Dung; Shy-Chaung Lin

1999-01-01

412

Experimental investigation of absorption and dispersion in multi-V-type cesium atomic system  

Microsoft Academic Search

Electromagnetically induced transparency (EIT) is observed in a three-level multi-V-type system in cesium vapor at room temperature. The absorption and dispersion properties are measured under the condition that the coupling frequency is exactly resonance with transition 6S½(F=4) to 6P3\\/2F'=3) while the probe frequency is scanned across the transitions from the 6S½(F=4$) to all structures of the 6P3\\/2. The effects of

Jian-ming Zhao; Yanting Zhao; Lirong Wang; Liantuan Xiao; Suotang Jia

2002-01-01

413

A conceptual demonstration of freeze desalination-membrane distillation (FD-MD) hybrid desalination process utilizing liquefied natural gas (LNG) cold energy.  

PubMed

The severe global water scarcity and record-high fossil oil price have greatly stimulated the research interests on new desalination technologies which can be driven by renewable energy or waste energy. In this study, a hybrid desalination process comprising freeze desalination and membrane distillation (FD-MD) processes was developed and explored in an attempt to utilize the waste cold energy released from re-gasification of liquefied natural gas (LNG). The concept of this technology was demonstrated using indirect-contact freeze desalination (ICFD) and direct-contact membrane distillation (DCMD) configurations. By optimizing the ICFD operation parameters, namely, the usage of nucleate seeds, operation duration and feed concentration, high quality drinkable water with a low salinity ?0.144 g/L was produced in the ICFD process. At the same time, using the optimized hollow fiber module length and packing density in the DCMD process, ultra pure water with a low salinity of 0.062 g/L was attained at a condition of high energy efficiency (EE). Overall, by combining FD and MD processes and adopting the optimized operation parameters, the hybrid FD-MD system has been successfully demonstrated. A high total water recovery of 71.5% was achieved, and the water quality obtained met the standard for drinkable water. In addition, with results from specific energy calculation, it was proven that the hybrid process is an energy-saving process and utilization of LNG cold energy could greatly reduce the total energy consumption. PMID:22682269

Wang, Peng; Chung, Tai-Shung

2012-09-01

414

Experimental and analytical analyses of the mechanisms governing the dispersion of flammable clouds formed by liquid hydrogen spills  

NASA Technical Reports Server (NTRS)

This paper presents the initial findings of hydrogen vapor cloud dispersion experiments conducted by NASA. The experiments were performed to obtain basic information regarding the physical phenomena governing the dispersion of flammable clouds formed as the result of spills of large quantities of liquid hydrogen. The experiments consisted of ground spills of up to 5.7 cu m of liquid hydrogen with spill durations of approx. 35 s. Instrumented towers, located downwind of the spill site, gathered data on the temperature, hydrogen concentration and turbulence levels as the hydrogen vapor cloud drifted downwind. Preliminary results of the experiments indicate that, for rapid spills, thermal and momentum-induced turbulences cause the cloud to disperse to safe concentration levels and become positively buoyant long before mixing due to normal atmospheric turbulence becomes a major factor. An adiabatic mixing model has been developed to deduce hydrogen-air mixture ratios for temperature measurements obtained within the cloud formed by liquid hydrogen spills.

Witcofski, R. D.; Chirivella, J. E.

1984-01-01

415

CO2 DIAL measurements of water vapor  

NASA Technical Reports Server (NTRS)

CO2 lidars have heretofore been used to measure water vapor concentrations primarily using the 10R(20) line at 10.247 microns, which has a strong overlap with a water vapor absorption line. This paper discusses the use of that line as well as other CO2 laser lines for which the absorption coefficients are weaker. The literature on measurement of water vapor absorption coefficients using CO2 lasers is reviewed, and the results from four laboratories are shown to be generally consistent with each other after they are normalized to the same partial pressure, temperature, and ethylene absorption coefficent for the 10P(14) CO2 laser line; however, the agreement with the Air Force Geophysics Laboratory's HITRAN and FASCOD 2 spectral data tapes is not good either for the water vapor absorption lines or for the water vapor continuum. Demonstration measurements of atmospheric water vapor have been conducted using the Mobile Atmospheric Pollutant Mapping System, a dual CO2 lidar system using heterodyne detection. Results are discussed for measurements using three sets of laser line pairs covering a wide range of water vapor partial pressures.

Grant, William B.; Margolis, Jack S.; Brothers, Alan M.; Tratt, David M.

1987-01-01

416

Vaporization of perfluorocarbon droplets using optical irradiation  

PubMed Central

Micron-sized liquid perfluorocarbon (PFC) droplets are currently being investigated as activatable agents for medical imaging and cancer therapy. After injection into the bloodstream, superheated PFC droplets can be vaporized to a gas phase for ultrasound imaging, or for cancer therapy via targeted drug delivery and vessel occlusion. Droplet vaporization has been previously demonstrated using acoustic methods. We propose using laser irradiation as a means to induce PFC droplet vaporization using a method we term optical droplet vaporization (ODV). In order to facilitate ODV of PFC droplets which have negligible absorption in the infrared spectrum, optical absorbing nanoparticles were incorporated into the droplet. In this study, micron-sized PFC droplets loaded with silica-coated lead sulfide (PbS) nanoparticles were evaluated using a 1064 nm laser and ultra-high frequency photoacoustic ultrasound (at 200 and 375 MHz). The photoacoustic response was proportional to nanoparticle loading and successful optical droplet vaporization of individual PFC droplets was confirmed using photoacoustic, acoustic, and optical measurements. A minimum laser fluence of 1.4 J/cm2 was required to vaporize the droplets. The vaporization of PFC droplets via laser irradiation can lead to the activation of PFC agents in tissues previously not accessible using standard ultrasound-based techniques.

Strohm, Eric; Rui, Min; Gorelikov, Ivan; Matsuura, Naomi; Kolios, Michael

2011-01-01

417

Dispersion coefficients for coastal regions  

SciTech Connect

The Nuclear Regulatory Commission (NRC) has undertaken an extensive atmospheric dispersion research and measurement program from which it is intended will emerge improved predictive techniques for employment in licensing decisions and for emergency planning and response. Through this program the NRC has conducted field measurement programs over a wide range of geographic and topographic locations, and are using the acquired tracer and meteorological measurements to evaluate existing dispersion models and prediction techniques, and to develop new techniques when necessary.

MacRae, B.L.; Kaleel, R.J.; Shearer, D.L.

1983-03-01

418

Solvent-free oil dispersant  

US Patent & Trademark Office Database

The present invention is directed toward an oil dispersant composition useful in treating oil spills, and for cleanup of the shoreline, animals, plants, and equipment. The oil dispersant product is a non-toxic, solvent-free composition which efficiently breaks down grease, grime and crude oil at the molecular level, by breaking down the hydrocarbon chains and preventing the oil molecules from ever reforming again.

2013-04-09

419

Predation risk increases dispersal distance in prey.  

PubMed

Understanding the ecological factors that affect dispersal distances allows us to predict the consequences of dispersal. Although predator avoidance is an important cause of prey dispersal, its effects on dispersal distance have not been investigated. We used simple experimental setups to test dispersal distances of the ambulatory dispersing spider mite (Tetranychus kanzawai) in the presence or absence of a predator (Neoseiulus womersleyi). In the absence of predators, most spider mites settled in adjacent patches, whereas the majority of those dispersing in the presence of predators passed through adjacent patches and settled in distant ones. This is the first study to experimentally demonstrate that predators induce greater dispersal distance in prey. PMID:24821118

Otsuki, Hatsune; Yano, Shuichi

2014-06-01

420

Predation risk increases dispersal distance in prey  

NASA Astrophysics Data System (ADS)

Understanding the ecological factors that affect dispersal distances allows us to predict the consequences of dispersal. Although predator avoidance is an important cause of prey dispersal, its effects on dispersal distance have not been investigated. We used simple experimental setups to test dispersal distances of the ambulatory dispersing spider mite (Tetranychus kanzawai) in the presence or absence of a predator (Neoseiulus womersleyi). In the absence of predators, most spider mites settled in adjacent patches, whereas the majority of those dispersing in the presence of predators passed through adjacent patches and settled in distant ones. This is the first study to experimentally demonstrate that predators induce greater dispersal distance in prey.

Otsuki, Hatsune; Yano, Shuichi

2014-05-01

421

The evolution of density-dependent dispersal  

PubMed Central

Despite a large body of empirical evidence suggesting that the dispersal rates of many species depend on population density, most metapopulation models assume a density-independent rate of dispersal. Similarly, studies investigating the evolution of dispersal have concentrated almost exclusively on density-independent rates of dispersal. We develop a model that allows density-dependent dispersal strategies to evolve. Our results demonstrate that a density-dependent dispersal strategy almost always evolves and that the form of the relationship depends on reproductive rate, type of competition, size of subpopulation equilibrium densities and cost of dispersal. We suggest that future metapopulation models should account for density-dependent dispersal

Travis, J. M. J.; Murrell, D. J.; Dytham, C.

1999-01-01

422

Predation risk increases dispersal distance in prey  

NASA Astrophysics Data System (ADS)

Understanding the ecological factors that affect dispersal distances allows us to predict the consequences of dispersal. Although predator avoidance is an important cause of prey dispersal, its effects on dispersal distance have not been investigated. We used simple experimental setups to test dispersal distances of the ambulatory dispersing spider mite ( Tetranychus kanzawai) in the presence or absence of a predator ( Neoseiulus womersleyi). In the absence of predators, most spider mites settled in adjacent patches, whereas the majority of those dispersing in the presence of predators passed through adjacent patches and settled in distant ones. This is the first study to experimentally demonstrate that predators induce greater dispersal distance in prey.

Otsuki, Hatsune; Yano, Shuichi

2014-06-01

423

Vapor barrier properties of polycaprolactone montmorillonite nanocomposites: effect of clay dispersion  

Microsoft Academic Search

Different compositions of poly(?-caprolactone) (PCL) and (organo-modified) montmorillonite were prepared by melt blending or catalyzed ring opening polymerization of ?-caprolactone. Microphase composites were obtained by direct melt blending of PCL and sodium montmorillonite (MMT-Na+). Exfoliated nanocomposites were obtained by in situ ring opening polymerization of ?-caprolactone with an organo-modified montmorillonite (MMT-(OH)2) by using dibutyltin dimethoxide as an initiator\\/catalyst. Intercalated nanocomposites

Giuliana Gorrasi; Mariarosaria Tortora; Vittoria Vittoria; Eric Pollet; Bénédicte Lepoittevin; Michael Alexandre; Philippe Dubois

2003-01-01

424

Recovering hydrocarbons from hydrocarbon-containing vapors  

DOEpatents

Values are recovered from a hydrocarbon-containing vapor by contacting the vapor with quench liquid consisting essentially of hydrocarbons to form a condensate and a vapor residue, the condensate and quench fluid forming a combined liquid stream. The combined liquid stream is mixed with a viscosity-lowering liquid to form a mixed liquid having a viscosity lower than the viscosity of the combined liquid stream to permit easy handling of the combined liquid stream. The quench liquid is a cooled portion of the mixed liquid. Viscosity-lowering liquid is separated from a portion of the mixed liquid and cycled to form additional mixed liquid.

Mirza, Zia I. (La Verne, CA); Knell, Everett W. (Los Alamitos, CA); Winter, Bruce L. (Danville, CA)

1980-09-30

425

GEWEX Water Vapor Project (GVaP)  

NASA Technical Reports Server (NTRS)

The goal of the Global Energy and Water Cycle Experiment (GEWEX) Water Vapor Project (GVaP) is to improve the understanding of water vapor in meteorological, hydrological, and climatological processes through improving knowledge of water vapor and its variability on all scales. This goal clearly requires a multiscale observing strategy. A pilot project was deemed the most appropriate first step toward achieving this goal. An implementation plan was developed for this pilot phase. The four research components of the pilot phase are presented here.

Starr, David

1993-01-01

426

Water vapor retrieval over many surface types  

SciTech Connect

In this paper we present a study of of the water vapor retrieval for many natural surface types which would be valuable for multi-spectral instruments using the existing Continuum Interpolated Band Ratio (CIBR) for the 940 nm water vapor absorption feature. An atmospheric code (6S) and 562 spectra were used to compute the top of the atmosphere radiance near the 940 nm water vapor absorption feature in steps of 2.5 nm as a function of precipitable water (PW). We derive a novel technique called ``Atmospheric Pre-corrected Differential Absorption`` (APDA) and show that APDA performs better than the CIBR over many surface types.

Borel, C.C.; Clodius, W.C.; Johnson, J.

1996-04-01

427

Infrared absorption of explosive molecule vapors  

NASA Astrophysics Data System (ADS)

Infrared absorption spectra have been obtained for the high explosive molecules TNT, RDX, and PETN in the vapor phase. Integrated band strengths were measured for the symmetric and antisymmetric -NO 2 vibrations in each of these molecules. Ab initio calculations of vibrational frequencies and intensities were carried out for comparison with the experimental data. Previous measurements of the heats of vaporization of these materials were checked using the temperature dependence of infrared band intensities. Measurements were also carried out on ammonium nitrate; in this case, only the decomposition products NH 3, HNO 3, and N 2O were observed in the vapor phase in equilibrium with the solid.

Janni, James; Gilbert, Brian D.; Field, R. W.; Steinfeld, Jeffrey I.

1997-08-01

428

FEM3 modeling of ammonia and hydrofluoric acid dispersion. [A phase-change submodel  

SciTech Connect

FEM3 is a three-dimensional computer model that was designed to simulate the atmospheric dispersion of heavier-than-air gas releases. Recently a phase-change submodel based on local thermodynamic equilibrium has been implemented to treat vapor-liquid transition of the dispersed material. A preliminary evaluation of the phase-change submodel was performed by using data obtained from two recently conducted series of field experiments, namely, the pressurized ammonia spills conducted by LLNL and the anhydrous hydrofluoric acid dispersion experiments conducted by Amoco Oil Company and LLNL. FEM3 results compare reasonably well with the good data available from one ammonia spill and two hydrofluoric acid spills and, in particular, the results obtained by using the phase-change submodel represent considerable improvements over those from all-vapor simulations. While the present phase-change submodel qualitatively handles the aerosol effects, including gravity flow and heat transfer between the vapor and droplets, it tends to over-estimate the rate of droplet evaporation. 16 refs., 12 figs., 7 tabs.

Chan, S.T.; Rodean, H.C.; Blewitt, D.N.

1987-07-01

429

Modeling of chemical vapor infiltration  

SciTech Connect

Ceramic matrix composites can be fabricated by chemical vapor infiltration (CVI) of a fibrous preform. In conventional processing, the reactant gases diffuse into the preform under isothermal conditions, depositing material onto the fibers and forming a continuous matrix as coating thickness increases. This technique usually requires several weeks to achieve high density. Recent development of a forced flow, thermal gradient technique can reduce infiltration time to several hours. While successful composites have been produced, understanding of the process and its critical parameters is incomplete. In order to gain this insight an analytical model of this process is being developed. The developed CVI model will simulate the infiltration process based on input of the controlling process parameters and preform properties. Providing detailed information on the composition of the partially dense composite throughout the process period, the model will allow rapid selection of optimum processing conditions for a particular preform. Beyond this, the model also can be used to design the preform (geometry and fiber architecture) and the infiltration reactor. The CVI model is developed based on fundamentals of mass and heat transport and on the microstructure and physical properties of the preform and matrix materials. 36 refs., 28 figs., 2 tabs.

Starr, T.L.

1989-02-01

430

Microwave assisted chemical vapor infiltration  

SciTech Connect

The purpose of this program is to develop a new process for the fabrication of ceramic matrix composites by chemical vapor infiltration. This period has been devoted in part to the exploration of material systems suitable for MACVI processing. A number of potential processing schemes are possible using combinations of absorbing and transparent material as composite components. This includes the use of an absorbing preform (nicalon fiber) combined with a transparent matrix (silicon nitride). Composites 5 cm in diameter by 1 cm. thick have been fabricated to densities of 65% theoretical. Processing times for these materials are under 20 hours. Higher densities will require additional microwave power now possible with the new reactor. The most effective MACVI scheme will involve the use of a transparent fiber with an absorbing matrix. The hot spot will be initiated by appropriate treatment of the central region of the preform. To this end alumna fibers with pretreatments to control thermal gradients has been explored. Nextel 610 fibers have been effectively pretreated carbon coating resulting in preferential heating in the interior of the preform. Possible matrix materials include siliconized silicon carbide, doped silicon carbide, alumna and zirconia. A patent for MACVI has been issued 10/19/93.

Devlin, D.J.

1993-12-31

431

Fundamentals of Chemical Vapor Deposition  

NSDL National Science Digital Library

This web page offers a tutorial by Daniel M. Dobkin, Ph.D, proprietor of Enigmatics Consulting of Sunnyvale, California that introduces fundamental principles of chemical vapor deposition of films. Topics covered include CVD Basics, Review of Ideal Gases, Review of Kinetic Theory, Zero-Dimensional Transport: Stirred Reactor, Transport in Gaseous Media, Chemistry for CVD, Plasmas for CVD, CVD Films, and CVD Reactor Designs. According to the author, "The tutorial assumes a general background roughly equivalent to a BS degree in the physical sciences. The aspects of thermodynamics, statistical mechanics, chemistry, and electromagnetism needed for understanding CVD processes are reviewed here, but only in sufficient depth to remind the reader of a past acquaintance with the topicsÃÂ. Some knowledge of the basics of semiconductor manufacturing is also helpful in following the discussion of films and applications." Visitors are free to copy and use any materials in the site, so long as licensing conditions stipulated by Creative Commons are met. (Details of the license can be found by clicking on a hyperlink to Creative Commons.)

Dobkin, Daniel M.

2012-12-11

432

Discharge excitation of dye vapors  

NASA Astrophysics Data System (ADS)

Experiments have been conducted to assess the feasibility of obtaining a discharge-pumped dye vapor laser. A 15 (or 50) cm active length, UV-preionized device has been developed which exhibits a specific power loading of the medium of approx. 5 MW/cu cm and will operate continuously at temperatures exceeding 400 C. Recently, hydrogen thyratron switching of the device and corona preionization have been installed to minimize jitter and dye fragmentation. Optimization of the rare gas/N2 diluent mixture has been completed and fragmentation studies for several dye molecules have been conducted. POPOP and alpha-NPO are excellent in the latter regard but Coumarin 6 rapidly decomposes in the discharge environment. The fluorescence efficiency of alpha-NPO is only 40 percent of that for POPOP under comparable conditions. BBO and PBBO are similar in structure and molecular weight to POPOP and appear to be excellent candidates for discharge excitation. Fluorescence and small signal gain measurements are in progress.

Eden, J. G.

1987-09-01

433

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

NASA Technical Reports Server (NTRS)

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 transported somehow through the tropopause, the vapor pressure being controlled by the temperature at the tops of the clouds; the dryness of the stratosphere could be explained if most of the transport occurs in connection with very high clouds in regions with very high and cold tropopause. (3) Cumulo-nimbus anvils act as terrestrial-radiation shields allowing the ice particle temperatures near cloud tops to cool radiatively below the supersaturation point; this cooling would cause a vapor deposition on the ice particles which will settle out and thus act as water scavengers. The experiment was designed to collect information on these detailed physical processes near and above the tropopause in order to assess their importance and the role they play in controlling stratospheric water vapor humidity.

Page, William A.

1982-01-01

434

Probe for measurement of velocity and density of vapor in vapor plume  

DOEpatents

A probe which directs a light beam through a vapor plume in a first direction at a first angle ranging from greater than 0.degree. to less than 90.degree., reflecting the light beam back through the vapor plume at a 90.degree. angle, and then reflecting the light beam through the vapor plume a third time at a second angle equal to the first angle, using a series of mirrors to deflect the light beam while protecting the mirrors from the vapor plume with shields. The velocity, density, temperature and flow direction of the vapor plume may be determined by a comparison of the energy from a reference portion of the beam with the energy of the beam after it has passed through the vapor plume.

Berzins, Leon V. (Livermore, CA); Bratton, Bradford A. (Bethel Island, CA); Fuhrman, Paul W. (Livermore, CA)

1997-01-01

435

Remote sensing of water vapor features  

NASA Technical Reports Server (NTRS)

Water vapor plays a critical role in the atmosphere. It is an important medium of energy exchange between air, land, and water; it is a major greenhouse gas, providing a crucial radiative role in the global climate system; and it is intimately involved in many regional scale atmospheric processes. Our research has been aimed at improving satellite remote sensing of water vapor and better understanding its role in meteorological processes. Our early studies evaluated the current GOES VAS system for measuring water vapor and have used VAS-derived water vapor data to examine pre-thunderstorm environments. Much of that research was described at the 1991 Research Review. A second research component has considered three proposed sensors--the High resolution Interferometer Sounder (HIS), the Multispectral Atmospheric Mapping Sensor (MAMS), and the Advanced Microwave Sounding Unit (AMSU). We have focused on MAMS and AMSU research during the past year and the accomplishments made in this effort are presented.

Fuelberg, Henry E.

1993-01-01

436

Water vapor recovery from plant growth chambers  

NASA Technical Reports Server (NTRS)

NASA is investigating the use of plant growth chambers (PGCs) for space missions and for bases on the moon and Mars. Key to successful development of PGCs is a system to recover and reuse the water vapor that is transpired from the leaves of the plants. A design is presented for a simple, reliable, membrane-based system that allows the recovery, purification, and reuse of the transpired water vapor through control of temperature and humidity levels in PGCs. The system is based on two membrane technologies: (1) dehumidification membrane modules to remove water vapor from the air, and (2) membrane contactors to return water vapor to the PGC (and, in doing so, to control the humidity and temperature within the PGC). The membrane-based system promises to provide an ideal, stable growth environment for a variety of plants, through a design that minimizes energy usage, volume, and mass, while maximizing simplicity and reliability.

Ray, R. J.; Newbold, D. D.; Colton, R. H.; Mccray, S. B.

1991-01-01

437

Colorometric detection of ethylene glycol vapor  

NASA Technical Reports Server (NTRS)

Very low concentrations of ethylene glycol in air or other gases are detected by passing a sample through a glass tube with three partitioned compartments containing reagents which successively convert the ethylene glycol vapor into a colored compound.

Helm, C.; Mosier, B.; Verostko, C. E.

1970-01-01

438

Study of the Constrained Vapor Bubble Thermosyphon.  

National Technical Information Service (NTIS)

The objective of this effort is to better understand the physics of evaporation, condensation, and fluid flow as they affect the heat transfer processes in a constrained vapor bubble heat exchanger (CVBHX). This CVBHX consists of a small enclosed containe...

P. C. Wayner J. L. Plawsky

2000-01-01

439

High Temperature Water Vapor Electrolysis (Hot Elly).  

National Technical Information Service (NTIS)

The practicability of high temperature water vapor electrolysis was demonstrated on a laboratory scale. The component raw materials selection is described, and the manufacture of high temperature electrolysis cells is delineated. Electrolytic operation of...

W. Doenitz H. Hermeking I. Kitzmann A. Koch R. Roettenbacher

1980-01-01

440

High Temperature Water Vapor Electrolysis (HOT ELLY).  

National Technical Information Service (NTIS)

The objective of the project HOT ELLY (phase 1) was the demonstration of the practicability of high temperature water vapor electrolysis on a laboratory scale. Starting from basic material studies the components (using sufficiently cheap raw materials) as...

W. Doenitz H. Hermeking I. Kitzmann A. Koch R. Roettenbacher

1980-01-01

441

Current Regulator For Sodium-Vapor Lamps  

NASA Technical Reports Server (NTRS)

Regulating circuit maintains nearly-constant alternating current in sodium-vapor lamp. Regulator part of dc-to-ac inverter circuit used to supply power to street lamp from battery charged by solar-cell array.

Mclyman, W. T.

1989-01-01

442

Chemical vapor infiltration using microwave energy.  

National Technical Information Service (NTIS)

This invention is comprised of a method for producing reinforced ceramic composite articles by means of chemical vapor infiltration and deposition in which an inverted temperature gradient is utilized. Microwave energy is the source of heat for the proces...

D. J. Devlin R. P. Currier J. R. Laia R. S. Barbero

1992-01-01

443

Chemical vapor infiltration using microwave energy  

SciTech Connect

A method for producing reinforced ceramic composite articles by means of chemical vapor infiltration and deposition in which an inverted temperature gradient is utilized. Microwave energy is the source of heat for the process. 5 figures.

Devlin, D.J.; Currier, R.P.; Laia, J.R. Jr.; Barbero, R.S.

1993-10-19

444

Chemical vapor infiltration in single fiber bundles.  

National Technical Information Service (NTIS)

Chemical vapor infiltration (CVI) in single fiber bundles is studied under isothermal conditions. Understanding infiltration dynamics in single bundles is essential to process design and modeling efforts. Deposition of pyrolytic carbon in carbon-fiber bun...

D. J. Devlin R. P. Currier R. S. Barbero

1990-01-01

445

Chemical vapor infiltration process modeling and optimization.  

National Technical Information Service (NTIS)

Chemical vapor infiltration is a unique method for preparing continuous fiber ceramic composites that spares the strong but relatively fragile fibers from damaging thermal, mechanical, and chemical degradation. The process is relatively complex and modeli...

T. M. Besmann D. P. Stinton W. M. Matlin

1995-01-01

446

Chemical vapor infiltration using microwave energy  

SciTech Connect

A method for producing reinforced ceramic composite articles by means of chemical vapor infiltration and deposition in which an inverted temperature gradient is utilized. Microwave energy is the source of heat for the process.

Devlin, David J. (Los Alamos, NM); Currier, Robert P. (Los Alamos, NM); Laia, Jr., Joseph R. (Los Alamos, NM); Barbero, Robert S. (Santa Cruz, NM)

1993-01-01

447

Apparatus for Producing Gaseous Vapor Baffle.  

National Technical Information Service (NTIS)

This patent application discloses an apparatus that produces a gaseous vapor baffle that isolates an undersea sonar system from acoustic noise. The apparatus allows for craft carrying undersea sonar systems to travel at relatively high speeds while substa...

T. J. Gieseke

2004-01-01

448

Peptides and Proteins in the Vapor Phase  

NASA Astrophysics Data System (ADS)

This article provides a review of recent studies of the properties of unsolvated (and partially solvated) peptides and proteins. The methods used to produce vapor-phase peptide and protein ions are described along with some of the techniques used to study them, such as H/D exchange, blackbody infrared radiative dissociation, and ion mobility measurements. Studies of unsolvated peptides and proteins provide information about their intrinsic intramolecular interactions. The topics covered include the role of zwitterions and salt bridges in the vapor phase, Coulomb interactions in multiply charged ions, the unfolding and refolding of vapor-phase proteins, and the stability of unsolvated helices and sheets. Finally, dehydration and rehydration studies of proteins in the vapor phase are described. These can provide exquisitely detailed information about hydration interactions, such as the enthalpy and entropy changes associated with adsorbing individual water molecules.

Jarrold, Martin F.

2000-10-01

449

A System for Vapor Cooling Electronic Equipment.  

National Technical Information Service (NTIS)

The patent application pertains generally to heat transfer systems and more particularly to a closed system for cooling electronic equipment. A vapor cooling system comprises a liquid boiled by heat from a magnetron and collected and forced upward by the ...

H. Boehm

1976-01-01

450

Perfluorocarbon vapor tagging of blasting cap detonators  

DOEpatents

A plug for a blasting cap is made of an elastomer in which is dissolved a perfluorocarbon. The perfluorocarbon is released as a vapor into the ambient over a long period of time to serve as a detectable taggant.

Dietz, Russell N. (Shoreham, NY); Senum, Gunnar I. (Patchogue, NY)

1981-01-01

451

External fuel vaporization study, phase 1  

NASA Technical Reports Server (NTRS)

A conceptual design study was conducted to devise and evaluate techniques for the external vaporization of fuel for use in an aircraft gas turbine with characteristics similar to the Energy Efficient Engine (E(3)). Three vaporizer concepts were selected and they were analyzed from the standpoint of fuel thermal stability, integration of the vaporizer system into the aircraft engine, engine and vaporizer dynamic response, startup and altitude restart, engine performance, control requirements, safety, and maintenance. One of the concepts was found to improve the performance of the baseline E(3) engine without seriously compromising engine startup and power change response. Increased maintenance is required because of the need for frequent pyrolytic cleaning of the surfaces in contact with hot fuel.

Szetela, E. J.; Chiappetta, L.

1980-01-01

452

VAPOR PRESSURE DISTRIBUTION OF SELECTED ORGANIC CHEMICALS  

EPA Science Inventory

A tabulation of vapor pressures for organic chemical products currently considered for inclusion in fugitive emissions regulations was prepared. For each of the 378 chemicals (or groups of chemicals) identified by the Emission Standards and Engineering Division, the following dat...

453

Vapor Cavitation in Dynamically Loaded Journal Bearings  

NASA Technical Reports Server (NTRS)

High speed motion camera experiments were performed on dynamically loaded journal bearings. The length to diameter ratio of the bearing, the speed of the roller and the tube, the surface material of the roller, and the static and dynamic eccentricity of the bearing were varied. One hundred and thirty-four cases were filmed. The occurrence of vapor cavitation was clearly evident in the films and figures presented. Vapor cavitation was found to occur when the tensile stress applied to the oil exceeded the tensile strength of the oil or the binding of the oil to the surface. The physical situation in which vapor cavitation occurs is during the squeezing and sliding motion within a bearing. Besides being able to accurately capture the vapor cavitation on film, an analysis of the formation and collapse of the cavitation bubbles and characteristics of the bubble content are presented.

Jacobson, B. O.; Hamrock, B. J.

1983-01-01

454

Vapor Lubrication of High Speed Ball Bearings.  

National Technical Information Service (NTIS)

Amine dithiocarbamates prepared from amine compounds of low boiling point produced extended running times, however, the amine dithiocarbamates prepared from morpholine were ineffective as a vapor lubricant. It is considered that this effect which is signi...

L. Stallings

1965-01-01

455

POPOP vapor laser with a 22% efficiency  

NASA Astrophysics Data System (ADS)

Ether vapor at a pressure of 35 atm increased the equilibrium density of POPOP molecules in vapors by a factor of 100. When a mixture of POPOP vapor and ether was pumped by the third harmonic of a neodymium laser (355 nm), a lasing efficiency higher than 22% was obtained, this being comparable with the lasing efficiency of POPOP molecules in solutions. The low threshold intensity for excitation of laser action (Ith < 0.3 MW/cm2) when pumped by the fourth harmonic (266 nm) indicated that wide-band incoherent light sources can be used to pump POPOP vapor. For comparison, measurements were made of the lasing efficiency of lasers utilizing solutions of POPOP in dioxane (38%) and ether (50%). The fact that POPOP molecules retain their lasing properties at elevated temperatures also makes these potentially useful for solidstate lasers with porous matrices and for dye-aerosol lasers.

Logunov, O. A.; Startsev, Aleksandr V.; Sto?lov, Yu Yu

1981-07-01

456

Advanced Atmospheric Water Vapor DIAL Detection System.  

National Technical Information Service (NTIS)

Measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The remote sensing Differential Absorption Lidar (DIAL) technique is a powerful method to perform such measurement from aircraft and space. Thi...

T. F. Refaat H. E. Elsayed-Ali

2000-01-01

457

Impact of the vertical velocity scenario on modeling water vapor transport in the TTL  

NASA Astrophysics Data System (ADS)

To study transport and transformation of water vapor in the TTL we analyze high-resolution water measurements from the tropical aircraft mission SCOUT-O3 in Northern Australia. Therefore backtrajectories are initialized along the flight tracks and minimum saturation water, calculated from the minimum temperatures along the trajectories, is compared to the measurements. Furthermore, we assess the impact of the vertical velocity scenario on modeling stratospheric water vapor by calculating the trajectories in various kinematic and diabatic scenarios, with the vertical velocity either pressure tendency or deduced from diabatic heating rates. The extremely well agreement between trajectory reconstructed water vapor and measurements demonstrates that the water vapor set point in the TTL is primarily determined by the recent Lagrangian saturation history, with an additional moistening effect of deep convection. The impact of the vertical velocity scenario on the average tropical stratospheric water budget turns out to be small. However, modeling high-resolution in-situ water measurements favors a diabatic scenario, with reduced dispersion and no subsidence in the upper TTL and a more efficient sampling of cold point temperatures, compared to a kinematic scenario.

Ploeger, F.; Konopka, P.; Guenther, G.; Grooss, J.; Mueller, R.; Schiller, C.

2009-12-01

458

Sorption of Water Vapors by Armos Fibre  

Microsoft Academic Search

The extremely slow kinetics of absorption of water vapors by Armos fibre can be explained by notions concerning its cross-linked structure, which consists of units of the crystallite type and liquid-crystalline or amorphous crosslinks and has a relatively high density. Sorption of water vapors by the initial Armos fibre not treated with heat is much higher than for the heat-treated

L. Ya. Konovalova; M. M. Iovleva; G. S. Negodyaeva; G. A. Budnitskii; N. N. Machalaba

2003-01-01

459

Application of Thioether for Vapor Phase Lubrication  

NASA Technical Reports Server (NTRS)

The objective of these studies was to identify the optimal conditions for vapor phase lubrication using Thioether for both sliding and rolling wear. The important variable include; (1) The component materials including M50 steel, monel and silicon nitride. (2) The vapor concentration and flow rate. (3) The temperature in the range of 600 F to 1500 F. (4) The loads and rolling and/or sliding speeds.

Graham, E. Earl

1997-01-01

460

Solid-state barium-vapor detector  

Microsoft Academic Search

The need for electrical switching devices for use in high-temperature radioactive environments in space nuclear power systems has led to the development of the cesium-barium tacitron. Effective evaluation of electrically insulating joints for the barium-cesium tacitron requires a method for the in situ detection of barium vapor which may leak through the joint. A solid-state barium-vapor detector has been developed

Jeffrey W. Fergus; S. Hui

1995-01-01

461

Optical-fiber arrays for vapor sensing  

Microsoft Academic Search

This paper reviews the use of optical fibers as a platform to fabricate vapor sensitive arrays that have been developed in the authors’ laboratory in recent years. Two types of fluorescence-based optical-fiber array systems are described: polymer-coated single core optical fibers and imaging fiber-optic bundles incorporating functionalized microspheres. Each system responds to an analyte vapor in a cross-reactive manner generating

Matthew J. Aernecke; David R. Walt

2009-01-01

462

Metal Vapor Arcing Risk Assessment Tool  

NASA Technical Reports Server (NTRS)

The Tin Whisker Metal Vapor Arcing Risk Assessment Tool has been designed to evaluate the risk of metal vapor arcing and to help facilitate a decision toward a researched risk disposition. Users can evaluate a system without having to open up the hardware. This process allows for investigating components at risk rather than spending time and money analyzing every component. The tool points to a risk level and provides direction for appropriate action and documentation.

Hill, Monika C.; Leidecker, Henning W.

2010-01-01

463

Diode pumped alkali vapor fiber laser  

Microsoft Academic Search

A method and apparatus is provided for producing near-diffraction-limited laser light, or amplifying near-diffraction-limited light, in diode pumped alkali vapor photonic-band-gap fiber lasers or amplifiers. Laser light is both substantially generated and propagated in an alkali gas instead of a solid, allowing the nonlinear and damage limitations of conventional solid core fibers to be circumvented. Alkali vapor is introduced into

Stephen A. Payne; Raymond J. Beach; Jay W. Dawson; William F. Krupke

2007-01-01

464

Diode pumped alkali vapor fiber laser  

Microsoft Academic Search

A method and apparatus is provided for producing near-diffraction-limited laser light, or amplifying near-diffraction-limited light, in diode pumped alkali vapor photonic-band-gap fiber lasers or amplifiers. Laser light is both substantially generated and propagated in an alkali gas instead of a solid, allowing the nonlinear and damage limitations of conventional solid core fibers to be circumvented. Alkali vapor is introduced into

Stephen A. Payne; Raymond J. Beach; Jay W. Dawson; William F. Krupke

2006-01-01

465

Harmonic generation in organic dye vapors  

Microsoft Academic Search

Investigations of nonlinear optical frequency conversion of Nd:YAG laser radiation in naphthalene vapors are presented. The third harmonic generation (THG) caused by difference frequency generation in six-photon process has been studied. Phase-matching temperature for naphthalene vapor was found to be 170°C, at which synchronous conversion of pump radiation to the third harmonic was carried out. The THG conversion efficiency varied

R. A. Ganeev; Sh. R. Kamalov; M. K. Kodirov; M. R. Malikov; A. I. Ryasnyansky; R. I. Tugushev; Sh. U. Umidullaev; T. Usmanov

2000-01-01

466

Difference frequency generation in organic vapors  

Microsoft Academic Search

Investigations of nonlinear-optical frequency conversion of Nd:YAG laser radiation in naphthalene vapors are presented. Third harmonic generation caused by difference frequency generation in six-photon process was offered. Optimum temperature for naphthalene vapor was found to be 170 degree(s)C, at which the synchronous conversion of pump radiation to the third harmonic radiation was carried out. Third harmonic generation conversion efficiency varied

R. A. Ganeev; Shavkat R. Kamalov; M. K. Kodirov; M. R. Milikov; Alexander I. Ryasnyansky; R. I. Tugushev; Sh. U. Umidullaev; Timurbek Usmanov

2000-01-01

467

Vapor-Pressure Measurements by Effusion Methods.  

National Technical Information Service (NTIS)

Vapor pressure measurements were made on FeCl2, FeBr2, FeI2, Sb, Bi, Cd, Mg, Pb, FeCl3, and VCl2 using the Knudsen and torsion effusion methods and on FeCl3-NaCl mixtures, Au2Cl6 and MgNi2 using only the Knudsen method. Apparent vapor pressures calculated...

A. Landsberg A. Adams S. D. Hill

1977-01-01

468

A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium.  

PubMed

The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D(2) transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude. PMID:17902946

McCarron, Daniel J; Hughes, Ifan G; Tierney, Patrick; Cornish, Simon L

2007-09-01

469

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

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

470

Dispersal mechanisms of the narrow endemic Polygala vayredae : dispersal syndromes and spatio-temporal variations in ant dispersal assemblages  

Microsoft Academic Search

This study assesses the dispersal mechanisms of the narrow endemic Polygala vayredae, analysing the functioning of its dispersal syndromes (anemochory and myrmecochory), the spatio-temporal variability of the\\u000a disperser assemblage, foraging behaviour and dispersal ability, and the role of the elaiosome in ant attraction and seed germination.\\u000a The dispersion of diaspores begins when either (1) capsules or seeds fall beneath the

Sílvia Castro; Victoria Ferrero; João Loureiro; Xavier Espadaler; Paulo Silveira; Luis Navarro

2010-01-01

471

Dispersion-managed soliton in a strong dispersion map limit  

Microsoft Academic Search

A dispersion-managed optical system with step-wise periodical variation of\\u000adispersion is studied in a strong dispersion map limit in the framework of\\u000apath-averaged Gabitov-Turitsyn equation. The soliton solution is obtained by\\u000aiterating the path-averaged equation analytically and numerically. An efficient\\u000anumerical algorithm for obtaining of DM soliton shape is developed. The\\u000aenvelope of soliton oscillating tails is found to decay

P. M. Lushnikov

2001-01-01

472

Amplified dispersive delay generator using angular dispersion amplification.  

PubMed

Angular dispersion amplification can be used to design compact dispersive delay generators with delay amplification. A specific design is presented that can be used to generate 1 ns delay for two wavelengths separated by 1 nm. The delay generator can be easily switched from a positive to a negative group velocity delay and can be used as a pulse compressor, a pulse stretcher, or a pulse shaper in chirped pulse amplification, high-resolution time-gated spectroscopy as well as other applications. PMID:19823234

Basu, Santanu

2009-10-10

473

Optical monitor for water vapor concentration  

DOEpatents

A system for measuring and monitoring water vapor concentration in a sample uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to a water vapor absorption line. In a preferred embodiment, the argon line is split by a magnetic field parallel to the direction of light propagation from the lamp into sets of components of downshifted and upshifted frequencies of approximately 1575 Gauss. The downshifted components are centered on a water vapor absorption line and are thus readily absorbed by water vapor in the sample; the upshifted components are moved away from that absorption line and are minimally absorbed. A polarization modulator alternately selects the upshifted components or downshifted components and passes the selected components to the sample. After transmission through the sample, the transmitted intensity of a component of the argon line varies as a result of absorption by the water vapor. The system then determines the concentration of water vapor in the sample based on differences in the transmitted intensity between the two sets of components. In alternative embodiments alternate selection of sets of components is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to the emitting plasma. 5 figs.

Kebabian, P.

1998-06-02

474

Vapor Deposits in the Lunar Regolith  

NASA Technical Reports Server (NTRS)

Since the Apollo missions, we have emphasized the following points, which are based on theoretical calculations and on laboratory studies of the properties of evaporated silicate deposits and of lunar samples. The mass of vapor generated by impacts on the lunar surface is comparable in magnitude to the mass of impact melt glasses; the physics of impact into a porous regolith requires that much of this vapor be retained in the soil rather than lost to space (as is widely believed); experimental coatings made from vaporized or sputtered lunar basalt contain abundant inclusions of submicroscopic, super paramagnetic metallic Fe; and this Fe may explain the magnetic signature, low albedo, reddened spectrum, and subdued absorption bands of lunar regolith. Our conclusions have been generally rejected by the lunar geochemical community for two reasons: there seemed to be no direct evidence for vapor deposits in Apollo samples, and it seemed that the lunar optical properties could be explained by the presence of impact melt glasses alone. However, advances in our understanding of the optical properties of glasses and of light scattering by planetary regoliths, and now the direct detection of vapor deposits, show that these objections are not valid. Vapor phase transport is a major process on the lunar surface, and unless its effects are taken into account, the chemical, magnetic, and optical properties of the regolith cannot be understood.

Hapke, Bruce; Cassidy, William; Wells, Eddie

1994-01-01

475

Optical monitor for water vapor concentration  

DOEpatents

A system for measuring and monitoring water vapor concentration in a sample uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to a water vapor absorption line. In a preferred embodiment, the argon line is split by a magnetic field parallel to the direction of light propagation from the lamp into sets of components of downshifted and upshifted frequencies of approximately 1575 Gauss. The downshifted components are centered on a water vapor absorption line and are thus readily absorbed by water vapor in the sample; the upshifted components are moved away from that absorption line and are minimally absorbed. A polarization modulator alternately selects the upshifted components or downshifted components and passes the selected components to the sample. After transmission through the sample, the transmitted intensity of a component of the argon line varies as a result of absorption by the water vapor. The system then determines the concentration of water vapor in the sample based on differences in the transmitted intensity between the two sets of components. In alternative embodiments alternate selection of sets of components is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to the emitting plasma.

Kebabian, Paul (Acton, MA)

1998-01-01

476

VIS absorption spectrophotometry of disperse dyes  

Microsoft Academic Search

In the investigations of the dyeing processes, the low solubility of disperse dyes in water represents a practical problem for the determination of dye concentration in dyebaths and waste waters. Therefore the use of an organic solvent which, dissolves disperse dyes, is recommended in visible spectrophotometry of disperse dyes. Three organic solvents (ethanol, N,N-dimethylformamide, acetone) and two disperse dyes, the

Vera Golob; Lidija Tušek

1999-01-01

477

DISPERSANT EFFECTIVENESS AT VARIOUS SEA STATES  

EPA Science Inventory

In 2002, a dispersant effectiveness protocol, which tested the effectiveness of dispersants to disperse crude oil into the water column, was developed. A new and highly reproducible protocol that uses a baffled flask as the primary vehicle for getting the oil dispersed has emerge...

478

Controlling Metal-Halide Vapor Density in Lasers  

NASA Technical Reports Server (NTRS)

Streams of buffer gas convect and dilute metal-halide vapor. Technique uses flow of buffer gas through reservoir, which contains heated metal halide, to convect vapors into discharge tube. Second stream of buffer gas dilutes vapor. Final vapor density in laser tube controlled and changed by adjusting either one or both of buffer gas flow rates.

Pivirotto, T. J.

1984-01-01

479

Melting, ablation, and vapor phase condensation during atmospheric passage of the Bjurbole meteorite  

NASA Technical Reports Server (NTRS)

A detailed study of the Bjurbole fusion crust using scanning electron microscopy (SEM) and energy dispersive analysis (EDS) shows that filamentary crystals and ablation spheres may form on the meteoroid surface. Filamentary crystals, hollow spheres, and porous regions of the surface point to a period of intense vapor phase activity during atmospheric passage. Filamentary crystals can be divided into three categories on the basis of bulk composition and morphology. Two types of filamentary crystals are vapor phase condensation products formed during atmospheric entry of the meteoroid. The other type forms by the interaction of seawater with the fusion surface. The density and composition of ablation spheres varies with the flight orientation of the meteorite. The size range and composition of iron-nickel spheres on the surface of Bjurbole are similar to spheres collected in the stratosphere. A comparison of stratospheric dust collections with meteorite surfaces may provide further insight into the mechanisms of meteoroid entry into planetary atmospheres.

Rietmeijer, F. J. M.; Mackinnon, I. D. R.

1984-01-01

480

Modeling and Simulation of Effects of Turbulence on Vaporization, Mixing and Combustion of Liquid-Fuel Sprays  

Microsoft Academic Search

The objective of this work is twofold. Firstly, the effects of turbulence intensity variations on the turbulent droplet dispersion,\\u000a vaporization and mixing for non-reacting sprays (with and without swirl) are pointed out. Secondly, the effects of the coupling\\u000a of the turbulence modulation with external parameters, such as swirl intensity, on turbulent spray combustion are analyzed\\u000a in configurations of engineering importance.

A. Sadiki; M. Chrigui; J. Janicka; M. R. Maneshkarimi

2005-01-01

481

CO oxidation activity of Cu–CeO 2 nano-composite catalysts prepared by laser vaporization and controlled condensation  

Microsoft Academic Search

Ceria supported copper catalysts were synthesized by laser vaporization and controlled condensation method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDAX) and temperature programmed reduction (TPR). The catalytic activity of the nanopowders for CO oxidation reaction was tested in a fixed bed flow tube reactor in Ar–20%O2–4%CO mixture. Irrespective of the copper content,

Rangaraj S. Sundar; Sarojini Deevi

2006-01-01

482

Absorption resonances in 'Lambda'-type three-level system in cesium vapor cell with buffer gas  

Microsoft Academic Search

We report experimentally the transformation from the electromagnetically induced transparency (EIT) resonance to a dispersion-like signal and eventually to a nearly symmetric absorption resonance as coupling detuning increases in 'Lambda'-type three-level system in the cesium vapor cell with buffer gas at room temperature. The observed absorption resonance occupies some remarkable properties of the strong amplitude and the narrow linewidth in

Jie Ma; Yanting Zhao; Lirong Wang; Jianming Zhao; Liantuan Xiao; Suotang Jia

2006-01-01

483

Temporal Dispersion of a Spectrometer  

SciTech Connect

The temporal dispersion of an optical spectrometer has been characterized for a variety of conditions related to optical diagnostics to be fielded at the National Ignition Facility (e.g., Full-Aperture Backscatter Station, Thomson Scattering). Significant time smear is introduced into these systems by the path length difference through the spectrometer. The temporal resolution can be calculated to depend only on the order of the grating, wavelength, and the number of grooves illuminated. To enhance the temporal dispersion, the spectral gratings can be masked limiting the number of grooves illuminated. Experiments have been conducted to verify these calculations. The size and shape of masks are investigated and correlated to the exact shape of the temporal instrument function, which is required when interpreting temporally resolved data. The experiments used a 300fs laser pulse and a picosecond optical streak camera to determine the temporal dispersion. This was done for multiple spectral orders, gratings, and optical masks.

Visco, A; Drake, R P; Froula, D H; Glenzer, S H

2008-05-08

484

Inter- and intramolecular dispersion interactions.  

PubMed

We have investigated the performance of a variety of density functional methods for weak intra- and intermolecular dispersion interactions. Grimme's empirical dispersion correction method is shown to give a good description for these interactions and helps to improve the description of water-hexamer isomers, noble-gas dimers, hydrocarbon C(12)H(12) isomers, branching energy of linear versus branched octane, dissociation of the covalently bound anthracene dimer, and stacking within the adenine dimer. However, the dispersion correction does not correct all shortcomings of the different density functionals, which leads to sizeable differences compared to ab initio CCSD(T) and experimental reference data. The only exception is shown to be our recently presented SSB-D functional that works well for all systems studied here. PMID:21387338

Swart, Marcel; Solà, Miquel; Bickelhaupt, F Matthias

2011-04-30

485

Vapor phase diamond growth technology  

NASA Technical Reports Server (NTRS)

Ion beam deposition chambers used for carbon film generation were designed and constructed. Features of the developed equipment include: (1) carbon ion energies down to approx. 50 eV; (2) in suit surface monitoring with HEED; (3) provision for flooding the surface with ultraviolet radiation; (4) infrared laser heating of substrate; (5) residual gas monitoring; (6) provision for several source gases, including diborane for doping studies; and (7) growth from either hydrocarbon source gases or from carbon/argon arc sources. Various analytical techniques for characterization of from carbon/argon arc sources. Various analytical techniques for characterization of the ion deposited carbon films used to establish the nature of the chemical bonding and crystallographic structure of the films are discussed. These include: H2204/HN03 etch; resistance measurements; hardness tests; Fourier transform infrared spectroscopy; scanning auger microscopy; electron spectroscopy for chemical analysis; electron diffraction and energy dispersive X-ray analysis; electron energy loss spectroscopy; density measurements; secondary ion mass spectroscopy; high energy electron diffraction; and electron spin resonance. Results of the tests are summarized.

Angus, J. C.

1981-01-01

486

Evaluation of dispersants for gelcasting  

SciTech Connect

Dispersants were evaluated for producing fluid and pourable 50 vol % alumina slurries for use in aqueous gelcasting. The best dispersants are anionic polyelectrolytes with carboxylic acid sites. The major mechanism by which the anionic polyelectrolytes stabilize aqueous alumina suspensions is electrostatic. However, the presence of Mg(NO{sub 3}){sub 2}, a precursor for MgO used as sintering aid for the alumina, and acrylamide monomer, used to form the gel, enhances the steric contribution of the adsorbed polymer to the interaction between alumina particles.

Omatete, O.O.; Bleier, A.

1992-01-01

487

Evaluation of dispersants for gelcasting  

SciTech Connect

Dispersants were evaluated for producing fluid and pourable 50 vol % alumina slurries for use in aqueous gelcasting. The best dispersants are anionic polyelectrolytes with carboxylic acid sites. The major mechanism by which the anionic polyelectrolytes stabilize aqueous alumina suspensions is electrostatic. However, the presence of Mg(NO{sub 3}){sub 2}, a precursor for MgO used as sintering aid for the alumina, and acrylamide monomer, used to form the gel, enhances the steric contribution of the adsorbed polymer to the interaction between alumina particles.

Omatete, O.O.; Bleier, A.

1992-05-01

488

Dispersion forces inside metallic waveguides  

NASA Astrophysics Data System (ADS)

We consider the dispersion energy of a pair of dipoles embedded in a metallic waveguide with transverse dimension a smaller than the characteristic dipolar wavelength. We find that a sets the scale that separates retarded, Casimir-Polder-like from quasistatic, van der Waals-like interactions. Whereas in the retarded regime the energy decays exponentially with interdipolar distance, typical of evanescent waves, in the van der Waals regime, the known free-space result is obtained. This short-range scaling implies that the additivity of the dispersion interactions inside a waveguide extends to denser media, along with modifications to related Casimir effects in such structures.

Shahmoon, Ephraim; Kurizki, Gershon

2013-06-01

489

Printed circuit dispersive transmission line  

DOEpatents

A printed circuit dispersive transmission line structure is disclosed comprising an insulator, a ground plane formed on one surface of the insulator, a first transmission line formed on a second surface of the insulator, and a second transmission line also formed on the second surface of the insulator and of longer length than the first transmission line and periodically intersecting the first transmission line. In a preferred embodiment, the transmission line structure exhibits highly dispersive characteristics by designing the length of one of the transmission line between two adjacent periodic intersections to be longer than the other.

Ikezi, Hiroyuki (Rancho Santa Fe, CA); Lin-Liu, Yuh-Ren (San Diego, CA); DeGrassie, John S. (Encinitas, CA)

1991-01-01

490

Dispersion-compensated Fresnel lens  

DOEpatents

A transmission grating is used to reduce chromatic aberration in a Fresnel lens, wherein the lens chromatic dispersion is offset and substantially canceled by the grating's diffraction-induced dispersion. The grating comprises a Fresnel-type pattern of microscopic facets molded directly into the lens surface. The facets would typically have a profile height of around 4[times]10[sup [minus]5] inch and a profile width of at least 10[sup [minus]3] inch. In its primary intended application, the invention would function to improve the optical performance of a Fresnel lens used to concentrate direct sunlight. 10 figs.

Johnson, K.C.

1992-11-03

491

Dispersion-compensated fresnel lens  

DOEpatents

A transmission grating is used to reduce chromatic aberration in a Fresnel lens, wherein the lens chromatic dispersion is offset and substantially canceled by the grating's diffraction-induced dispersion. The grating comprises a Fresnel-type pattern of microscopic facets molded directly into the lens surface. The facets would typically have a profile height of around 4.multidot.10.sup.-5 inch and a profile width of at least 10.sup.-3 inch. In its primary intended application, the invention would function to improve the optical performance of a Fresnel lens used to concentrate direct sunlight.

Johnson, Kenneth C. (1215 Brewster Dr., El Cerrito, CA 94530)

1992-01-01

492

Fog dispersion. [charged particle technique  

NASA Technical Reports Server (NTRS)

The concept of using the charged particle technique to disperse warm fog at airports is investigated and compared with other techniques. The charged particle technique shows potential for warm fog dispersal, but experimental verification of several significant parameters, such as particle mobility and charge density, is needed. Seeding and helicopter downwash techniques are also effective for warm fog disperals, but presently are not believed to be viable techniques for routine airport operations. Thermal systems are currently used at a few overseas airports; however, they are expensive and pose potential environmental problems.

Christensen, L. S.; Frost, W.

1980-01-01

493

Printed circuit dispersive transmission line  

DOEpatents

A printed circuit dispersive transmission line structure is disclosed comprising an insulator, a ground plane formed on one surface of the insulator, a first transmission line formed on a second surface of the insulator, and a second transmission line also formed on the second surface of the insulator and of longer length than the first transmission line and periodically intersecting the first transmission line. In a preferred embodiment, the transmission line structure exhibits highly dispersive characteristics by designing the length of one of the transmission line between two adjacent periodic intersections to be longer than the other. 5 figures.

Ikezi, H.; Lin-Liu, Y.R.; DeGrassie, J.S.

1991-08-27

494

Dispersion-optimized optical fiber for high-speed long-haul dense wavelength division multiplexing transmission  

NASA Astrophysics Data System (ADS)

Four non-zero-dispersion-shifted fibers with almost the same large effective area (Aeff) and optimized dispersion properties are realized by novel index profile designing and modified vapor axial deposition and modified chemical vapor deposition processes. An Aeff of greater than 71 ?m2 is obtained for the designed fibers. Three of the developed fibers with positive dispersion are improved by reducing the 1550nm dispersion slope from 0.072ps/nm2/km to 0.063ps/nm2/km or 0.05ps/nm2/km, increasing the 1550nm dispersion from 4.972ps/nm/km to 5.679ps/nm/km or 7.776ps/nm/km, and shifting the zero-dispersion wavelength from 1500nm to 1450nm. One of these fibers is in good agreement with G655D and G.656 fibers simultaneously, and another one with G655E and G.656 fibers; both fibers are beneficial to high-bit long-haul dense wavelength division multiplexing systems over S-, C-, and L-bands. The fourth developed fiber with negative dispersion is also improved by reducing the 1550nm dispersion slope from 0.12ps/nm2/km to 0.085ps/nm2/km, increasing the 1550nm dispersion from -4ps/nm/km to -6.016ps/nm/km, providing facilities for a submarine transmission system. Experimental measurements indicate that the developed fibers all have excellent optical transmission and good macrobending and splice performances.

Wu, Jindong; Chen, Liuhua; Li, Qingguo; Wu, Wenwen; Sun, Keyuan; Wu, Xingkun

2011-07-01

4