Sample records for gas evaporation method

  1. A full evaporation headspace gas chromatographic method for determination of monomer conversion in cellulose graft poly-methyl methacrylate

    Microsoft Academic Search

    Jin-Feng Zhong; Xin-Sheng Chai; Xiao-Li Qin; Shi-Yu Fu

    2011-01-01

    This paper reports on a full evaporation headspace gas chromatographic method for rapid determination of monomeric methyl methacrylate (MMA) in the cellulose graft poly-methyl methacrylate (PMMA) via an atom transfer radical polymerization process. The data show that a near-complete mass transfer of MMA from the very small liquid sample size (<30mg) to the vapor phase (headspace) was achieved within 5min

  2. Method of evaporation

    NASA Technical Reports Server (NTRS)

    Dufresne, Eugene R.

    1987-01-01

    Liquids, such as juices, milk, molten metal and the like are concentrated by forming uniformly-sized, small droplets in a precision droplet forming assembly and deploying the droplets in free fall downwardly as a central column within an evacuated column with cool walls. A portion of the solvent evaporates. The vapor flows to the wall, condenses, and usually flows down the wall as a film to condensate collector and drain. The vertical column of freely falling droplets enters the splash guard. The condensate can be collected, sent to other towers or recycled.

  3. Evaporation of forsterite in H 2 gas

    Microsoft Academic Search

    Hiroko Nagahara; Kazuhito Ozawa

    1996-01-01

    Kinetics of evaporation of forsterite in hydrogen gas was investigated by high temperature vacuum experiments in the pressure range plausible for the solar nebula. The evaporation rate at total pressure (Ptot) below 10?6 bar is nearly constant and is similar to that in vacuum, whereas the rate at 10?6 to 10?3 bar is dependent on Ptot. The evaporation rate, JexpFo,

  4. Resonant gas oscillation with evaporation and condensation

    NASA Astrophysics Data System (ADS)

    Inaba, Masashi; Yano, Takeru; Watanabe, Masao; Kobayashi, Kazumichi; Fujikawa, Shigeo

    2012-09-01

    Resonant gas oscillation in a closed tube bounded by an oscillating plate and a vaporliquid interface is theoretically analyzed by applying the asymptotic theory to the ES-BGK Boltzmann equation for the case of M2?Kn?1 and a small evaporation coefficient ? = O(Kn), where M and Kn are the typical Mach number and the Knudsen number, respectively. As a result, we derive a nonlinear integro-differential equation for determining the wave profile with the evaporation and condensation in the form including ?.

  5. On The Validity of the Assumed PDF Method for Modeling Binary Mixing/Reaction of Evaporated Vapor in GAS/Liquid-Droplet Turbulent Shear Flow

    NASA Technical Reports Server (NTRS)

    Miller, R. S.; Bellan, J.

    1997-01-01

    An Investigation of the statistical description of binary mixing and/or reaction between a carrier gas and an evaporated vapor species in two-phase gas-liquid turbulent flows is perfomed through both theroetical analysis and comparisons with results from direct numerical simulations (DNS) of a two-phase mixing layer.

  6. Chemical Potential Jump during Evaporation of a Quantum Bose Gas

    E-print Network

    E. A. Bedrikova; A. V. Latyshev

    2013-01-07

    The dependence of the chemical potential jump coefficient on the evaporation coefficient is analyzed for the case in which the evaporating component is a Bose gas. The concentration of the evaporating component is assumed to be much lower than the concentration of the carrier gas. The expression for the chemical potential jump is derived from the analytic solution of the problem for the case in which the collision frequency of molecules of the evaporating component is constant.

  7. Apparatus and method for evaporator defrosting

    DOEpatents

    Mei, Viung C. (Oak Ridge, TN); Chen, Fang C. (Knoxville, TN); Domitrovic, Ronald E. (Knoxville, TN)

    2001-01-01

    An apparatus and method for warm-liquid defrosting of the evaporator of a refrigeration system. The apparatus includes a first refrigerant expansion device that selectively expands refrigerant for cooling the evaporator, a second refrigerant expansion device that selectively expands the refrigerant after the refrigerant has passed through the evaporator, and a defrosting control for the first refrigerant expansion device and second refrigerant expansion device to selectively defrost the evaporator by causing warm refrigerant to flow through the evaporator. The apparatus is alternately embodied with a first refrigerant bypass and/or a second refrigerant bypass for selectively directing refrigerant to respectively bypass the first refrigerant expansion device and the second refrigerant expansion device, and with the defrosting control connected to the first refrigerant bypass and/or the second refrigerant bypass to selectively activate and deactivate the bypasses depending upon the current cycle of the refrigeration system. The apparatus alternately includes an accumulator for accumulating liquid and/or gaseous refrigerant that is then pumped either to a refrigerant receiver or the first refrigerant expansion device for enhanced evaporator defrosting capability. The inventive method of defrosting an evaporator in a refrigeration system includes the steps of compressing refrigerant in a compressor and cooling the refrigerant in the condenser such that the refrigerant is substantially in liquid form, passing the refrigerant substantially in liquid form through the evaporator, and expanding the refrigerant with a refrigerant expansion device after the refrigerant substantially passes through the evaporator.

  8. Measurement of the evaporation mass flow rate in a horizontal liquid layer partly opened into flowing gas

    NASA Astrophysics Data System (ADS)

    Lyulin, Yu. V.; Kabov, O. A.

    2013-09-01

    The dynamics of evaporation from a local surface of a horizontal liquid layer under a gas flow is studied experimentally. The average evaporation mass flow rate of a liquid layer (HFE-7100) induced by inert gas (nitrogen) is measured using two independent methods. The influence of the average gas flow rate, gas and liquid temperature, and the layer depth upon the evaporation rate and convection in the liquid layer is investigated. Correlation dependences of the evaporation rate vs. the inert gas flow rate and temperature are obtained. It is found that the average evaporation-rate curve has a local maximum with a growth of the liquid layer depth. With the growth of the gas and liquid temperature, the local maximum in an evaporation flow rate of the liquid layer is shifted to the larger value of the liquid depth.

  9. Inlet Fogging of Gas Turbine Engines Detailed Climatic Analysis of Gas Turbine Evaporation Cooling Potential in the USA

    Microsoft Academic Search

    Mustapha Chaker; Cyrus B. Meher-Homji; Thomas Mee III; Alex Nicholson

    2003-01-01

    Inlet fogging of gas turbine engines has attained considerable popularity due to the ease of installation and the relatively low first cost compared to other inlet cooling methods. With increasing demand for power and with shortages envisioned especially during the peak load times during the summers, there is a need to boost gas turbine power. There is a sizable evaporative

  10. Gas-assisted evaporative cooling of high density electronic modules

    Microsoft Academic Search

    Avram Bar-Cohen; Greg Sherwood; Marc Hodes; Gary Solbreken

    1995-01-01

    Gas-assisted evaporative cooling (GAEC), its advantages in thermal packaging of microelectronics, and its implementation in a prototype high-performance computer module, are described. Attention is then turned to theoretical considerations in the flow of gas-liquid-vapor mixtures in narrow, parallel plate channels, and to the design and operation of an appropriate experimental apparatus. Next, experimental results for the wall temperature, heat-transfer coefficients,

  11. High Rate Preparation of aSi:H by Reactive Evaporation Method

    Microsoft Academic Search

    Masanari Shindo; Shigeru Sato; Isao Myokan; Shigeru Mano; Takuji Shibata

    1984-01-01

    A high rate deposition method of a-Si: H based on reactive evaporation is described. a-Si: H prepared at a deposition rate of 30 Å\\/sec has much the same photoconductivity as films prepared by the glow discharge (GD) method. It is revealed that silicon oxidation due to residual oxygen gas is suppressed using a method of silicon evaporation to supply hydrogen

  12. Infiltration and evaporation of small hydrocarbon spills at gas stations

    NASA Astrophysics Data System (ADS)

    Hilpert, Markus; Breysse, Patrick N.

    2014-12-01

    Small gasoline spills frequently occur at gasoline dispensing stations. We have developed a mathematical model to estimate both the amount of gasoline that infiltrates into the concrete underneath the dispensing stations and the amount of gasoline that evaporates into the typically turbulent atmosphere. Our model shows that the fraction of infiltrated gasoline can exceed the fraction that evaporates from the sessile droplets. Infiltrated gasoline then evaporates and is slowly released to the atmosphere via slow diffusive transport in pores. Tentative experiments show that our theoretical approach captures observed experimental trends. Predictions based on independently estimated model parameters roughly describe the experimental data, except for the very slow vapor release at the end of Stage II evaporation. Our study suggests that, over the lifespan of a gas station, concrete pads underneath gas dispensing stations accumulate significant amounts of gasoline, which could eventually break through into underlying soil and groundwater. Our model also shows that lifetimes of spilled gasoline droplets on concrete surfaces are on the order of minutes or longer. Therefore contamination can be carried away by foot traffic or precipitation runoff. Regulations and guidelines typically do not address subsurface and surface contaminations due to chronic small gasoline spills, even though these spills could result in non-negligible human exposure to toxic and carcinogenic gasoline compounds.

  13. Evaporation

    NSDL National Science Digital Library

    James H. Kessler

    2007-01-01

    This three-part activity consists of an activity that groups of learners develop themselves, a given procedure, and an optional demonstration. First, learners discuss examples of evaporation and then design and conduct their own test to find out whether heating water has an effect on the rate of evaporation. While waiting for their results, learners conduct another evaporation activity using single drops of water on 2 paper towels, one of which is heated. The optional demonstration compares the rate of evaporation of hot and cold water using a sensitive scale or balance. In each of these experiences with evaporation, learners will identify variables, consider how to best control them, and use their observations to conclude that heating water increases the rate of evaporation.

  14. Fuel cell evaporative cooling using fuel as a carrier gas

    Microsoft Academic Search

    1991-01-01

    This patent describes a method of operating a fuel cell system. The system having a fuel stream, water, fuel, air, carbon monoxide, carbon dioxide, a hydro desulfurizer, a reformer, a low temperature shift converter, an evaporative cooler, means for heating, a contact cooler, a condenser, an exhaust, a fuel cell, the fuel cell having an anode chamber and a cathode

  15. Gas assisted thin-film evaporation from confined spaces

    NASA Astrophysics Data System (ADS)

    Narayanan, Shankar

    A novel cooling mechanism based on evaporation of thin liquid films is presented for thermal management of confined heat sources, such as microprocessor hotspots, high power light emitting diodes and RF packages with a high operational frequency. A thin nanoporous membrane (˜1--5microm) is utilized to maintain microscopically thin liquid films (˜1--5microm) by capillary action, while providing a pathway for the vapor generated due to evaporation at the liquid-vapor interface. The vapor generated by evaporation is continuously removed by using a dry sweeping gas, keeping the membrane outlet dry. This thesis presents a detailed theoretical, computational and experimental investigation of the heat and mass transfer mechanisms that result in cooling the confined heat sources. Performance analysis of this cooling mechanism demonstrates heat fluxes over 600W/cm2 for sufficiently thin membrane and film thicknesses (˜1--5microm) and by using air jet impingement for advection of vapor from the membrane surface. Based on the results from this performance analysis, a monolithic micro-fluidic device is designed and fabricated incorporating micro and nanoscale features. This MEMS/NEMS device serves multiple functionalities of hotspot simulation, temperature sensing, and evaporative cooling. Subsequent experimental investigations using this microfluidic device demonstrate heat fluxes in excess of 600W/cm2 at 90 °C using water as the evaporating coolant. In order to further enhance the device performance, a comprehensive theoretical and computational analysis of heat and mass transfer at micro and nanoscales is carried out. Since the coolant is confined using a nanoporous membrane, a detailed study of evaporation inside a nanoscale cylindrical pore is performed. The continuum analysis of water confined within a cylindrical nanopore determines the effect of electrostatic interaction and Van der Waals forces in addition to capillarity on the interfacial transport characteristics during evaporation. The detailed analysis demonstrates that the effective thermal resistance offered by the interface is negligible in comparison to the thermal resistance due to the thin film and vapor advection. In order to determine the factors limiting the performance of the MEMS device on a micro-scale, a device-level detailed computational analysis of heat and mass transfer is carried out, which is supported by experimental investigation. Identifying the contribution of various simultaneously occurring cooling mechanisms at different operating conditions, this analysis proposes utilization of hydrophilic membranes for maintaining very thin liquid films and further enhancement in vapor advection at the membrane outlet to achieve higher heat fluxes.

  16. Multilayer composite material and method for evaporative cooling

    NASA Technical Reports Server (NTRS)

    Buckley, Theresa M. (Inventor)

    2002-01-01

    A multilayer composite material and method for evaporative cooling of a person employs an evaporative cooling liquid that changes phase from a liquid to a gaseous state to absorb thermal energy. The evaporative cooling liquid is absorbed into a superabsorbent material enclosed within the multilayer composite material. The multilayer composite material has a high percentage of the evaporative cooling liquid in the matrix. The cooling effect can be sustained for an extended period of time because of the high percentage of phase change liquid that can be absorbed into the superabsorbent. Such a composite can be used for cooling febrile patients by evaporative cooling as the evaporative cooling liquid in the matrix changes from a liquid to a gaseous state to absorb thermal energy. The composite can be made with a perforated barrier material around the outside to regulate the evaporation rate of the phase change liquid. Alternatively, the composite can be made with an imperveous barrier material or semipermeable membrane on one side to prevent the liquid from contacting the person's skin. The evaporative cooling liquid in the matrix can be recharged by soaking the material in the liquid. The multilayer composite material can be fashioned into blankets, garments and other articles.

  17. Determination of soil evaporation fluxes using distributed temperature sensing methods

    NASA Astrophysics Data System (ADS)

    Serna, J. L.; Cristi Matte, F.; Munoz, J. F.; Suarez, F. I.

    2014-12-01

    The dynamics of evaporation fluxes in arid soils is an unresolved complex phenomenon that has a major impact on the basin's water availability. In arid zones, evaporation controls moisture contents near the soil surface and drives liquid water and water vapor fluxes through the vadose zone, playing a critical role in both the hydrological cycle and energy balance. However, determining soil evaporation in arid zones is a difficult undertaking. Thus, it is important to develop new measuring techniques that can determine evaporation fluxes. In the last decade, distributed temperature sensing (DTS) methods have been successfully used to investigate a wide range of hydrologic applications. In particular, DTS methods have been used indirectly to monitor soil moisture. Two methods have been developed: the passive and the active method. In the active mode, the DTS system uses cables with metal elements and a voltage difference is applied at the two ends to of the cable to heat it up for a defined time-period. Then, the cumulative temperature increase along the cable is computed and soil moisture is determined by using an empirical relation. DTS technology has also been used to determine water fluxes in porous media, but so far no efforts have been made to determine evaporation fluxes. Here, we investigate the feasibility of using the active DTS method to determine soil evaporation fluxes. To achieve this objective, column experiments were designed to study evaporation from sandy soils with shallow water tables. The soil columns were instrumented with traditional temperature and time-domain-reflectometry probes, and an armored fiber-optic cable that allows using the active method to estimate the soil moisture profile. In the experiments, the water table can be fixed at different depths and soil evaporation can be estimated by measuring the water added to the constant-head reservoir that feeds the column. Thus, allowing the investigation of soil evaporation fluxes from DTS measurements. The experiments consider different water table levels and meteorological conditions similar to those observed in arid zones with shallow groundwater tables. The experimental data will be used to estimate liquid water and water-vapor fluxes in porous media and to assess if DTS methods are suitable for studying soil evaporation fluxes.

  18. Surface and gas-phase resistances to the evaporation of droplets.

    PubMed

    Zung, J T

    1975-01-01

    Attempt has been made to asses quantitatively the magnitudes of both the gas-phase resistance and the surface resistance to the evaporation of droplets and to determine the transition point at which the evaporation changes from a diffusion-controlled to a surface-controlled process. This transition point is strongly dependent upon the ambient pressure and the droplet size. It is found that at atmospheric pressure the particle radius at which the transition takes place is in the range of 1 - 10mu for water, 0.1mu for n-dibutylphthalate, 0.1 - 1.0mu for mercury, and 0.001mu for liquid helium. Furthermore, we have found that the surface resistance and the gas-phase resistance vary with the size of the droplet in opposite direction, leading to the existence of a maximum rate of evaporation at a certain value of the droplet radius, this radius being dependent upon the characteristics of the liquid concerned. This conclusion may be useful in the search for an optimum and most efficient method of combustion of fuel sprays in automotive engines, gas turbines, and oil-burning power plants. PMID:1149699

  19. Method and apparatus for flash evaporation of liquids

    DOEpatents

    Bharathan, Desikan (Lakewood, CO)

    1984-01-01

    A vertical tube flash evaporator for introducing a superheated liquid into a flash evaporation chamber includes a vertical inlet tube with a flared diffuser portion at its upper outlet end. A plurality of annular screens are positioned in axially spaced-apart relation to each other around the periphery of the vertical tube and below the diffuser portion thereof. The screens are preferably curved upward in a cup-shaped configuration. These flash evaporators are shown in an ocean thermal energy conversion unit designed for generating electric power from differential temperature gradients in ocean water. The method of use of the flash evaporators of this invention includes flowing liquid upwardly through the vertical tube into the diffuser where initial expansion and boiling occurs quite violently and explosively. Unvaporized liquid sheets and drops collide with each other to enhance surface renewal and evaporation properties, and liquid flowing over the outlet end of the diffuser falls onto the curved screens for further surface renewal and evaporation.

  20. System and method for cooling a combustion gas charge

    DOEpatents

    Massey, Mary Cecelia; Boberg, Thomas Earl

    2010-05-25

    The present invention relates to a system and method for cooling a combustion gas charge prior. The combustion gas charge may include compressed intake air, exhaust gas, or a mixture thereof. An evaporator is provided that may then receive a relatively high temperature combustion gas charge and discharge at a relatively lower temperature. The evaporator may be configured to operate with refrigeration cycle components and/or to receive a fluid below atmospheric pressure as the phase-change cooling medium.

  1. A predictive method for crude oil volatile organic compounds emission from soil: evaporation and diffusion behavior investigation of binary gas mixtures.

    PubMed

    Wang, Haijing; Fischer, Thomas; Wieprecht, Wolfgang; Möller, Detlev

    2015-05-01

    Due to their mobility and toxicity, crude oil volatile organic compounds (VOCs) are representative components for oil pipeline contaminated sites detection. Therefore, contaminated location risk assessment, with airborne light detection and ranging (LIDAR) survey, in particular, requires ground-based determinative methods for oil VOCs, the interaction between oil VOCs and soil, and information on how they diffuse from underground into atmosphere. First, we developed a method for determination of crude oil VOC binary mixtures (take n-pentane and n-hexane as examples), taking synergistic effects of VOC mixtures on polydimethylsiloxane (PDMS) solid-phase microextraction (SPME) fibers into consideration. Using this method, we further aim to extract VOCs from small volumes, for example, from soil pores, using a custom-made sampling device for nondestructive SPME fiber intrusion, and to study VOC transport through heterogeneous porous media. Second, specific surface Brunauer-Emmett-Teller (BET) analysis was conducted and used for estimation of VOC isotherm parameters in soil. Finally, two models were fitted for VOC emission prediction, and the results were compared to the experimental emission results. It was found that free diffusion mode worked well, and an empirical correction factor seems to be needed for the other model to adapt to our condition for single and binary systems. PMID:25572270

  2. THE EVAPORATION METHOD IN SPECTRAL ANALYSIS

    Microsoft Academic Search

    Shteinberg

    1962-01-01

    The rapid development of science and the use of new elements, especialiy ; in the atomic industry and the semiconductor technology, places a great emphasis ; on the purity of the materials, requiring analytical methods which are able to ; detect impurities in the 10⁻⁴ to 10⁻⁶% range; the specifications are ; expected to become even more rigorous in the

  3. Experimental study of incongruent evaporation kinetics of enstatite in vacuum and in hydrogen gas

    Microsoft Academic Search

    Shogo Tachibana; Akira Tsuchiyama; Hiroko Nagahara

    2002-01-01

    Variations in bulk Mg\\/Si ratios in the various groups of chondritic meteorites indicate that Mg\\/Si fractionation occurred in the primitive solar nebula. Enstatite (MgSiO3) evaporates incongruently forming forsterite (Mg2SiO4) as an evaporation residue; therefore, evaporation of enstatite produces Mg\\/Si variations in solid (Mg-rich) and gas (Si-rich) and must be considered as a probable process responsible for Mg\\/Si fractionation recorded in

  4. Performance improvement of a gas turbine cycle by using a desiccant-based evaporative cooling system

    Microsoft Academic Search

    Amir Abbas Zadpoor; Ali Hamedani Golshan

    2006-01-01

    This paper focuses on power augmentation of a typical gas turbine cycle by using a desiccant-based evaporative cooling system. This technique requires a desiccant-based dehumidifying process be used to direct the air through an evaporative cooler, which could be either media-based or spray type. This could assist the evaporative cooling cycle to make necessary adjustment for any possible installation defects

  5. Flash gas bypass for improving the performance of transcritical R744 systems that use microchannel evaporators

    Microsoft Academic Search

    Stefan Elbel; Pega Hrnjak

    2004-01-01

    The performance of transcritical R744 systems with direct expansion (DX) can be significantly improved by implementing a Flash Gas Bypass (FGB). The idea behind the concept is to bypass refrigerant vapor, created during the isenthalpic expansion process, around the evaporator. By feeding the evaporator with liquid refrigerant, pressure drop is reduced and refrigerant distribution is improved. With R744 as the

  6. Tribological performance of Cu?Ni alloy nanoparticles synthesized using a pulsed-wire evaporation method

    Microsoft Academic Search

    Jeongseok Oh; Changkyu Rhee

    2008-01-01

    Cu?Ni alloy nanoparticles were produced using a pulsed-wire evaporation method in Ar gas. The synthesized Cu?Ni alloy nanoparticles\\u000a had an average size of 150 nm, were spherical in shape and agglomerated. We investigated the tribological propeties of dispersion-stabilized\\u000a Cu?Ni alloy nanoparticles when used as a solid lubricant in oil at ambient temperature. The sedimentation behavior of Cu?Ni\\u000a alloy nanoparticles in

  7. Strong evaporative cooling of a trapped cesium gas.

    PubMed

    Guery-Odelin, D; Soeding, J; Desbiolles, P; Dalibard, J

    1998-04-13

    Using forced radio-frequency evaporation, we have cooled cesium atoms prepared in the sublevel F = -m(F) = 3 and confined in a magnetic trap. At the end of the evaporation ramp, the sample contains ~ 7000 atoms at 80 nK, corresponding to a phase space density 3 x 10(-2). A molecular dynamics approach, including the effect of gravity, gives a good account for the experimental data, assuming a scattering length larger than 300 Angstrom. PMID:19381197

  8. Results for the DWPF Slurry Mix Evaporator Condensate Tank, Off Gas Condensate Tank, And Recycle Collection Tank Samples

    SciTech Connect

    TERRI, FELLINGER

    2004-12-21

    The Defense Waste Processing Facility, DWPF, currently generates approximately 1.4 million gallons of recycle water per year during Sludge-Only operations. DWPF has minimized condensate generation to 1.4 million gallons by not operating the Steam Atomized Scrubbers, SASs, for the melter off gas system. By not operating the SASs, DWPF has reduced the total volume by approximately 800,000 gallons of condensate per year. Currently, the recycle stream is sent to back to the Tank Farm and processed through the 2H Evaporator system. To alleviate the load on the 2H Evaporator system, an acid evaporator design is being considered as an alternate processing and/or concentration method for the DWPF recycle stream. In order to support this alternate processing option, the DWPF has requested that the chemical and radionuclide compositions of the Off Gas Condensate Tank, OGCT, Slurry Mix Evaporator Condensate Tank, SMECT, Recycle Collection Tank, RCT, and the Decontamination Waste Treatment Tank, DWTT, be determined as a part of the process development work for the acid evaporator design. Samples have been retrieved from the OGCT, RCT, and SMECT and have been sent to the Savannah River National Laboratory, SRNL for this characterization. The DWTT samples have been recently shipped to SRNL. The results for the DWTT samples will be issued at later date.

  9. Likelihood ratio methods for forensic comparison of evaporated gasoline residues.

    PubMed

    Vergeer, P; Bolck, A; Peschier, L J C; Berger, C E H; Hendrikse, J N

    2014-12-01

    In the investigation of arson, evidence connecting a suspect to the fire scene may be obtained by comparing the composition of ignitable liquid residues found at the crime scene to ignitable liquids found in possession of the suspect. Interpreting the result of such a comparison is hampered by processes at the crime scene that result in evaporation, matrix interference, and microbial degradation of the ignitable liquid. Most commonly, gasoline is used as a fire accelerant in arson. In the current scientific literature on gasoline comparison, classification studies are reported for unevaporated and evaporated gasoline residues. In these studies the goal is to discriminate between samples of several sources of gasoline, based on a chemical analysis. While in classification studies the focus is on discrimination of gasolines, for forensic purposes a likelihood ratio approach is more relevant. In this work, a first step is made towards the ultimate goal of obtaining numerical values for the strength of evidence for the inference of identity of source in gasoline comparisons. Three likelihood ratio methods are presented for the comparison of evaporated gasoline residues (up to 75% weight loss under laboratory conditions). Two methods based on distance functions and one multivariate method were developed. The performance of the three methods is characterized by rates of misleading evidence, an analysis of the calibration and an information theoretical analysis. The three methods show strong improvement of discrimination as compared with a completely uninformative method. The two distance functions perform better than the multivariate method, in terms of discrimination and rates of misleading evidence. PMID:25498926

  10. Evaporation of iodine-containing off-gas scrubber solution

    DOEpatents

    Partridge, J.A.; Bosuego, G.P.

    1980-07-14

    Mercuric nitrate-nitric acid scrub solutions containing radioiodine may be reduced in volume without excessive loss of volatile iodine. The use of concentrated nitric acid during an evaporation process oxidizes the mercury-iodide complex to a less volatile mercuric iodate precipitate.

  11. Comparison of 15 evaporation methods applied to a small mountain lake in the northeastern USA

    Microsoft Academic Search

    Donald O. Rosenberry; Thomas C. Winter; Donald C. Buso; Gene E. Likens

    2007-01-01

    Few detailed evaporation studies exist for small lakes or reservoirs in mountainous settings. A detailed evaporation study was conducted at Mirror Lake, a 0.15 km2 lake in New Hampshire, northeastern USA, as part of a long-term investigation of lake hydrology. Evaporation was determined using 14 alternate evaporation methods during six open-water seasons and compared with values from the Bowen-ratio energy-budget

  12. Spectroscopic studies of rubidium vapour zone produced by thermal evaporation in noble gas

    Microsoft Academic Search

    Shosuke Mochizuki; Ken-ichi Inozume; Raphael Ruppin

    1999-01-01

    The time evolution of the extinction spectra of the rubidium vapour zone has been measured during the process of gas evaporation. The structure of the spectra and their time dependence show the occurrence of atoms, dimers, clusters and microcrystals. Also, they show a size trend in the surface plasma resonance frequency of rubidium clusters. Also, vapour species in each zone

  13. Evaporation from weighing precipitation gauges: impacts on automated gauge measurements and quality assurance methods

    NASA Astrophysics Data System (ADS)

    Leeper, R. D.; Kochendorfer, J.

    2015-06-01

    Evaporation from a precipitation gauge can cause errors in the amount of measured precipitation. For automated weighing-bucket gauges, the World Meteorological Organization (WMO) suggests the use of evaporative suppressants and frequent observations to limit these biases. However, the use of evaporation suppressants is not always feasible due to environmental hazards and the added cost of maintenance, transport, and disposal of the gauge additive. In addition, research has suggested that evaporation prior to precipitation may affect precipitation measurements from auto-recording gauges operating at sub-hourly frequencies. For further evaluation, a field campaign was conducted to monitor evaporation and its impacts on the quality of precipitation measurements from gauges used at U.S. Climate Reference Network (USCRN) stations. Two Geonor gauges were collocated, with one gauge using an evaporative suppressant (referred to as Geonor-NonEvap) and the other with no suppressant (referred to as Geonor-Evap) to evaluate evaporative losses and evaporation biases on precipitation measurements. From June to August, evaporative losses from the Geonor-Evap gauge exceeded accumulated precipitation, with an average loss of 0.12 mm h-1. The impact of evaporation on precipitation measurements was sensitive to the choice of calculation method. In general, the pairwise method that utilized a longer time series to smooth out sensor noise was more sensitive to gauge evaporation (-4.6% bias with respect to control) than the weighted-average method that calculated depth change over a smaller window (<+1% bias). These results indicate that while climate and gauge design affect gauge evaporation rates, computational methods also influence the magnitude of evaporation biases on precipitation measurements. This study can be used to advance quality insurance (QA) techniques used in other automated networks to mitigate the impact of evaporation biases on precipitation measurements.

  14. Modelling of liquefied petroleum gas spray development, evaporation and combustion

    Microsoft Academic Search

    A P F Yoong; A P Watkins

    2004-01-01

    The research reported in this paper is the computational part of a joint experimental\\/computational investigation of the possible utilization of liquefied petroleum gas (LPG) in a direct injection internal combustion engine. Many aspects of spray modelling have been investigated in the research. This paper concentrates on the implementation of three aspects, namely (a) the incorporation of LPG (butane or propane)

  15. Evaporation determined by the energy-budget method for Mirror Lake, New Hampshire

    USGS Publications Warehouse

    Winter, T.C.; Buso, D.C.; Rosenberry, D.O.; Likens, G.E.; Sturrock, A.M., Jr.; Mau, D.P.

    2003-01-01

    Evaporation was determined by the energy-budget method for Mirror Lake during the open water periods of 1982-1987. For all years, evaporation rates were low in spring and fall and highest during the summer. However, the times of highest evaporation rates varied during the 6 yr. Evaporation reached maximum rates in July for three of the years, in June for two of the years, and in August for one of the years. The highest evaporation rate during the 6-yr study was 0.46 cm d-1 during 27 May-4 June 1986 and 15-21 July 1987. Solar radiation and atmospheric radiation input to the lake and long-wave radiation emitted from the lake were by far the largest energy fluxes to and from the lake and had the greatest effect on evaporation rates. Energy advected to and from the lake by precipitation, surface water, and ground water had little effect on evaporation rates. In the energy-budget method, average evaporation rates are determined for energy-budget periods, which are bounded by the dates of thermal surveys of the lake. Our study compared evaporation rates calculated for short periods, usually ???1 week, with evaporation rates calculated for longer periods, usually ???2 weeks. The results indicated that the shorter periods showed more variability in evaporation rates, but seasonal patterns, with few exceptions, were similar.

  16. Laboratory Evaporation Testing Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant

    SciTech Connect

    Adamson, Duane J.; Nash, Charles A.; McCabe, Daniel J.; Crawford, Charles L.; Wilmarth, William R.

    2014-01-27

    The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream, LAW Off-Gas Condensate, from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of canistered glass waste forms. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to be within acceptable concentration ranges in the LAW glass. Diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task examines the impact of potential future disposition of this stream in the Hanford tank farms, and investigates auxiliary evaporation to enable another disposition path. Unless an auxiliary evaporator is used, returning the stream to the tank farms would require evaporation in the 242-A evaporator. This stream is expected to be unusual because it will be very high in corrosive species that are volatile in the melter (chloride, fluoride, sulfur), will have high ammonia, and will contain carryover particulates of glass-former chemicals. These species have potential to cause corrosion of tanks and equipment, precipitation of solids, release of ammonia gas vapors, and scale in the tank farm evaporator. Routing this stream to the tank farms does not permanently divert it from recycling into the WTP, only temporarily stores it prior to reprocessing. Testing is normally performed to demonstrate acceptable conditions and limits for these compounds in wastes sent to the tank farms. The primary parameter of this phase of the test program was measuring the formation of solids during evaporation in order to assess the compatibility of the stream with the evaporator and transfer and storage equipment. The origin of this LAW Off-Gas Condensate stream will be the liquids from the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP) from the LAW facility melter offgas system. The stream is expected to be a dilute salt solution with near neutral pH, and will likely contain some insoluble solids from melter carryover. The soluble components are expected to be mostly sodium and ammonium salts of nitrate, chloride, and fluoride. This stream has not been generated yet, and, thus, the composition will not be available until the WTP begins operation, but a simulant has been produced based on models, calculations, and comparison with pilot-scale tests. This report discusses results of evaporation testing of the simulant. Two conditions were tested, one with the simulant at near neutral pH, and a second at alkaline pH. The neutral pH test is comparable to the conditions in the Hanford Effluent Treatment Facility (ETF) evaporator, although that evaporator operates at near atmospheric pressure and tests were done under vacuum. For the alkaline test, the target pH was based on the tank farm corrosion control program requirements, and the test protocol and equipment was comparable to that used for routine evaluation of feed compatibility studies for the 242-A evaporator. One of the

  17. Trace gas exchange above the floor of a deciduous forest. 1. Evaporation and CO sub 2 efflux

    SciTech Connect

    Baldocchi, D.D.; Meyers, T.P. (NOAA Atmospheric Turbulence and Diffusion Division, Oak Ridge, TN (USA))

    1991-04-20

    The eddy correlation method has great potential for directly measuring trace gas fluxes at the floor of a forest canopy, but a thorough validation study has not been yet conducted. Another appeal of the eddy correlation method is its ability to study processes that regulate and modulate gas exchange between the soil/litter complex and the atmosphere that cannot be probed with chambers. In this paper, the authors report on eddy correlation measurements of water vapor, sensible heat, and carbon dioxide exchange that were made at the floor of a deciduous forest. The validity of the eddy correlation method to measure the emission of water vapor and CO{sub 2} from a deciduous forest floor is demonstrated by the ability to close the surface energy budget during periods that meet the requirements of the technique. Water vapor fluxes from a dry forest floor are strongly influenced by large-scale turbulent events that penetrate deep into the canopy. The frequency of these turbulent events prevents equilibrium evaporation rates from being achieved because the dynamic time constant for water vapor exchange is longer. Consequently, maximal evaporation rates are capped to rates defined by the product of the driving potential of the atmosphere and the surface conductance. On the other hand, evaporation from a wet forest floor proceeds at rates reaching or exceeding equilibrium evaporation and are highly correlated with static pressure fluctuations. CO{sub 2} efflux rates are governed by litter and soil temperature, as expected. But the authors also find a significant correlation between static pressure fluctuations and soil/litter CO{sub 2} exchange rates.

  18. Gas scavenging of insoluble vapors: Condensation of methyl salicylate vapor onto evaporating drops of water

    NASA Astrophysics Data System (ADS)

    Seaver, Mark; Peele, J. R.; Rubel, Glenn O.

    We have observed the evaporation of acoustically levitated water drops at 0 and 32% relative humidity in a moving gas stream which is nearly saturated with methyl salicylate vapor. The initial evaporation rate is characteristic of a pure water drop and gradually slows until the evaporation rate becomes that of pure methyl salicylate. The quantity of condensed methyl salicylate exceeds its Henry's law solubility in water by factors of more than 30-50. This apparent violation of Henry's law agrees with the concentration enhancements in the liquid phase found by glotfelty et al. (1987, Nature235, 602-605) during their field measurements of organophorus pesticides in fog water. Under our conditions, visual evidence demonstrates the presence of two liquid phases, thus invalidating the use of Henry's law. A continuum evaporation-condensation model for an immiscible two-component system which accounts for evaporative self-cooling of the drop correctly predicts the amount of methyl salicylate condensed onto the water drops.

  19. Fuel oil evaporation in swirling hot gas streams

    Microsoft Academic Search

    Baifang Zuo; E. Van Den Bulck

    1998-01-01

    As the limit on combustion generated pollutants is becoming more strict, a potentially ecological as well as economical new technology to decrease combustion generated pollutants by liquid fuel combustion is to adopt a fuel pre-vaporized, premixed combustion. This paper presents a study on the liquid fuel vaporizing and mixing processes. An effective method for the calculation of turbulent two phase

  20. Evaporative depolarization and spin transport in a unitary trapped Fermi gas

    SciTech Connect

    Parish, Meera M. [Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States); Princeton Center for Theoretical Science, Princeton University, Princeton, New Jersey 08544 (United States); Huse, David A. [Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States)

    2009-12-15

    We consider a partially spin-polarized atomic Fermi gas in a high-aspect-ratio trap, with a flux of predominantly spin-up atoms exiting the center of the trap. We argue that such a scenario can be produced by evaporative cooling, and we find that it can result in a substantially nonequilibrium polarization pattern for typical experimental parameters. We offer this as a possible explanation for the quantitative discrepancies in recent experiments on spin-imbalanced unitary Fermi gases.

  1. Photocatalytic Characteristics of TiO2 Films Deposited by Oxygen Plasma-Assisted Reactive Evaporation Method

    Microsoft Academic Search

    Tetsuya Sakai; Yuji Kuniyoshi; Wataru Aoki; Sho Ezoe; Tatsuya Endo; Yoichi Hoshi

    2008-01-01

    Titanium dioxide (TiO2) films were deposited by the oxygen plasma-assisted reactive evaporation (OPARE) method. TiO2 films with an anatase structure were formed when activated oxygen plasma was supplied to the substrate during deposition, whereas the films with a rutile structure were formed when nonactivated oxygen gas was supplied. These results were explained by the promotion of the oxidization of titanium

  2. Evaporative cooling of a two-component degenerate Fermi gas M. J. Holland, B. DeMarco, and D. S. Jin

    E-print Network

    Jin, Deborah

    Evaporative cooling of a two-component degenerate Fermi gas M. J. Holland, B. DeMarco, and D. S quantum degeneracy have employed a final stage of forced evaporative cooling 2 . Efficient evaporative degeneracy 15­18 . In evaporative cooling, a ``cut'' is made at a prescribed energy and all atoms

  3. Effects of intensive evaporative cooling on performance characteristics of land-based gas turbine

    SciTech Connect

    Utamura, Motoaki; Kuwahara, Takaaki; Murata, Hidetaro; Horii, Nobuyuki

    1999-07-01

    Injection of finely-atomized water droplets at inlet to compressor is demonstrated to increase the power and augment the efficiency of gas turbine using a 115MW simple cycle commercial power plant. Power-up mechanism of the present system is identified to be a composite of three existing methods. Design requirement on droplet diameter is discussed in view of blade erosion as well as evaporation efficiency within the compressor. Special spray nozzle to generate water droplets with sauter mean diameter of 10 {micro} m is developed and applied to demonstration test. Experiments show that injection of spray water of 1% to air mass ratio would increase power output by about 10% and thermal efficiency by 3% (relative) respectively. A newly introduced incremental efficiency defined as the ratio of incremental power to additional fuel energy is found to be in excess of 10% (absolute) over thermal efficiency in case without water injection and to be independent of spray amount. It is also revealed that the operation of water spraying suppresses dust deposition on compressor blades under proper control of water quality, which mitigates the deterioration of compressor adiabatic efficiency.

  4. Falling film evaporation on enhanced tubes, part 2: Prediction methods and visualization

    Microsoft Academic Search

    M. Christians; J. R. Thome

    For falling film evaporation, the most important thermal design parameters that need to be predicted are the onset of dryout, after which a severe degradation in the evaporator performance is found, and the local heat transfer performance in fully wet and partially dry conditions. Presently, based on the new data and previous data presented in Part 1, new methods for

  5. Validation of the doubly labeled water method in growing precocial birds: the importance of assumptions concerning evaporative water loss.

    PubMed

    Visser, G H; Schekkerman, H

    1999-01-01

    The doubly labeled water (DLW) method was validated against respiration gas analysis in growing precocial chicks of the black-tailed godwit (Limosa limosa) and the northern lapwing (Vanellus vanellus). To calculate the rate of CO2 production from DLW measurements, Lifson and McClintock's equations (6) and (35) were employed, as well as Speakman's equation (7.17) (all single-pool models). The average errors obtained with the first two equations (+7.2% and -11.6%, respectively) differed significantly from zero but not the error obtained with Speakman's equation (average: -2.9%). The latter error could be reduced by taking a fractional evaporative water loss of 0.13, instead of the value of 0. 25 recommended by Speakman. Application of different two-pool models resulted in relative errors of the DLW method of -15.9% or more. After employing the single-pool model with a fractional evaporative water loss value of 0.13, it was found that there was no relationship between the relative growth rate of the chick and the relative error of the DLW method. Recalculation of previously published results on Arctic tern (Sterna paradisaea) chicks revealed that the fit of the validation experiment could be considerably improved by employing a single-pool model and assuming a fractional evaporative water loss of 0.20 instead of the value of 0.50 taken originally. After employing the value of 0.20, it was found that there was no relationship between the relative growth rate of the chick and the relative error of the DLW method. This suggests that isotope incorporation into new body substances does not cause a detectable error. Thus, the DLW method seems to be applicable in young birds growing as fast as 20% d-1, after making adjustments for the fractional evaporative water loss. We recommend Speakman's equation (7.17) for general use in growing birds when evaporation is unknown. PMID:10603338

  6. A high order moment method simulating evaporation and advection of a polydisperse liquid spray

    NASA Astrophysics Data System (ADS)

    Kah, D.; Laurent, F.; Massot, M.; Jay, S.

    2012-01-01

    In this paper, we tackle the modeling and numerical simulation of sprays and aerosols, that is dilute gas-droplet flows for which polydispersity description is of paramount importance. Starting from a kinetic description for point particles experiencing transport either at the carrier phase velocity for aerosols or at their own velocity for sprays as well as evaporation, we focus on an Eulerian high order moment method in size and consider a system of partial differential equations (PDEs) on a vector of successive integer size moments of order 0 to N, N > 2, over a compact size interval. There exists a stumbling block for the usual approaches using high order moment methods resolved with high order finite volume methods: the transport algorithm does not preserve the moment space. Indeed, reconstruction of moments by polynomials inside computational cells coupled to the evolution algorithm can create N-dimensional vectors which fail to be moment vectors: it is impossible to find a size distribution for which there are the moments. We thus propose a new approach as well as an algorithm which is second order in space and time with very limited numerical diffusion and allows to accurately describe the advection process and naturally preserves the moment space. The algorithm also leads to a natural coupling with a recently designed algorithm for evaporation which also preserves the moment space; thus polydispersity is accounted for in the evaporation and advection process, very accurately and at a very reasonable computational cost. These modeling and algorithmic tools are referred to as the Eulerian Multi Size Moment (EMSM) model. We show that such an approach is very competitive compared to multi-fluid approaches, where the size phase space is discretized into several sections and low order moment methods are used in each section, as well as with other existing high order moment methods. An accuracy study assesses the order of the method as well as the low level of numerical diffusion on structured meshes. Whereas the extension to unstructured meshes is provided, we focus in this paper on cartesian meshes and two 2D test-cases are presented: Taylor-Green vortices and turbulent free jets, where the accuracy and efficiency of the approach are assessed.

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

    NASA Technical Reports Server (NTRS)

    Kandula, Max

    2012-01-01

    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.

  8. Performance Comparison on the Evaporative Gas Turbine Cycles Combined with Different CO2Capture Options

    Microsoft Academic Search

    H. Li; J. Yan

    2009-01-01

    This article studied the integration of CO2 capture with evaporative gas turbine (EvGT) cycles. Two CO2 capture technologies are involved: MEA-based (monoethanolamine-based) chemical-absorption capture and O2\\/CO2 recycle combustion capture. Based on them, three system configurations were analyzed: (1) EvGT cycle without CO2 capture, (2) EvGT cycle with chemical-absorption capture, and (3) EvGT cycle with O2\\/CO2 recycle combustion capture. Simulation results

  9. Evaluation of equilibrium and non-equilibrium evaporation models for many-droplet gas-liquid ow simulations

    E-print Network

    Miller, Richard S.

    . For gas temperatures at and above the boiling point, large deviations are found between the various model identically for low evaporation rates at gas temperatures signi®cantly lower than the boiling temperature values are calculated at either the wet-bulb or boiling temperature. The models based on the Langmuir

  10. Fabrication of versatile 3-D ternary nanostructures via gas-mediated metal evaporation.

    PubMed

    Worsfold, O; Wright, J P; Himmelhaus, M

    2008-11-01

    By combining nanosphere lithography (NSL) with metal evaporation at two different chamber pressures, ternary metallic nanostructures with 3D topography were fabricated and characterized by field emission gun scanning electron microscopy (FEG-SEM) and atomic force microscopy (AFM). The nanostructures consist of 340 nm silicon patches surrounded by a chromium mesh of varying height and gold triangular pillars with a height of 40 nm and a diameter of about 200 nm. While NSL was applied due to its ease of use, evaporation at different chamber pressures can be combined with any kind of template mask comprising convex shape to yield novel kinds of ternary nanostructures analogous to the ones presented here. The method shows to be more versatile than plasma-based deposition techniques due to avoidance of substrate charging effects and a freely adjustable chamber pressure. PMID:19198323

  11. A comparative study on the estimation of evapotranspiration using backpropagation neural network: Penman–Monteith method versus pan evaporation method

    Microsoft Academic Search

    Sheng-Feng Kuo; Feng-Wen Chen; Pei-Yu Liao; Chen-Wuing Liu

    The study compares the prediction performances of evapotranspiration by the FAO56 Penman–Monteith method and the pan evaporation\\u000a method using the artificial neural network. A backpropagation neural network was adopted to determine the relationship between\\u000a meteorological factors and evapotranspiration or evaporation. The evapotranspiration in the ChiaNan irrigated area of Tainan\\u000a was considered. Weather data compiled by Irrigation Experiment Station of ChiaNan

  12. Determination of evaporation from lake and reservoir surfaces using the heat balance method

    Microsoft Academic Search

    T. V. Kirillova; T. A. Ogneva; L. V. Nesina

    The paper presents some results of a study, carried out ai the Main Geophysical Observatory, on the development of methods for determining evaporation from lake and reservoir surfaces. The heat-balance equation forms the basis of these methods. Practical application of (he relationships obtained requires the use of observation data from coastal meteorological and actinometric stations. The methods allow us to

  13. Trace gas exchange above the floor of a deciduous forest: 1. Evaporation and CO2 efflux

    Microsoft Academic Search

    Dennis D. Baldocchi; Tilden P. Meyers

    1991-01-01

    The eddy correlation method has great potential for directly measuring trace gas fluxes at the floor of a forest canopy, but a thorough validation study has not been yet conducted. Another appeal of the eddy correlation method is its ability to study processes that regulate and modulate gas exchange between the soil\\/litter complex and the atmosphere that cannot be probed

  14. Video-taped sample evaporation in hot chambers simulating gas chromatography split/splitless injectors. I. Thermospray injection.

    PubMed

    Grob, K; Biedermann, M

    2000-11-01

    The processes in devices imitating vaporising injectors were visualised and video-taped using perylene as a fluorescent marker for non-evaporated samples. The observations in the context of thermospray injection are summarised. Partial evaporation inside the needle turns the solvent into a propellant which nebulises the sample liquid at the needle exit. Evaporation in the vaporising chamber occurs from fine droplets suspended in the gas phase. Empty injector liners are best suited; packings with glass wool or obstacles in the liner, like the cup, have no significant effect on the process observed. Non-evaporated (matrix) material forms aerosol particles which may enter the column together with the vapours, but most of them are transferred to the liner wall. Since solute material may be carried along, this is a possible source of matrix effects. PMID:11128208

  15. Gas liquefaction method and apparatus

    SciTech Connect

    Gates, R.G.

    1988-04-26

    A method of liquifying a stream of permanent gas comprising nitrogen utilizing a single fluid cycle is described comprising: (a) compressing the gas stream to a pressure of from about 75 to 90 atmosphere; (b) providing a nitrogen working fluid at a pressure of from about 75 to 90 atmospheres; (c) cooling the fluid to a temperature of from about 170 to 200 K; (d) work-expanding the fluid to a temperature of from about 107 to 120 K; (e) warming the work-expanded fluid by heat exchange countercurrently to the gas stream thereby providing refrigeration necessary to reduce the temperature of the gas to below its critical temperature.

  16. Development and testing of a method for efficient simulation of evaporation from a seepage face

    SciTech Connect

    Ahlers, C. Fredrik; Ghezzehei, Teamrat; Finsterle, Stefan

    2003-05-12

    Evaporation from the surface of a porous medium is a complex process, governed by interplay between (1) coupled liquid and vapor flow in the porous medium, and (2) relative humidity, temperature, and aerodynamic conditions in the surrounding air. In order to avoid the computational expense of explicitly simulating liquid, gas, and heat flow in the porous medium (and the possible further expense of simulating the flow of water vapor in the atmosphere), evaporative potentials can be treated in a simplified manner within a model where liquid is the only active phase. In the case of limited air mixing, evaporation can be approximated as a diffusion process with a linear vapor-concentration gradient. We have incorporated a simplified scheme into the EOS9 module of iTOUGH2 to represent evaporation as isothermal Fickian diffusion. This is notable because the EOS9 module solves a single equation describing saturated and unsaturated flow, i.e., phase transitions and vapor flow are not explicitly simulated. The new approach was applied to three simple problems and the results were compared to those obtained with analytical solutions or the EOS4 module, which explicitly considers advective and diffusive vapor flow. Where vapor flow within the porous medium can be neglected, this new scheme represents significant improvement over the computational expense of explicitly simulating liquid, gas, and heat flow, while providing an adequate reproduction of the overall hydrologic system. The scheme is set up to allow parallel flow of liquid and vapor, so that evaporation from an actively seeping face can be simulated. In addition, dynamic relative humidity boundary conditions can be simulated using standard iTOUGH2 features.

  17. OT1_cjoblin_1: Physics of gas evaporation at PDR edges

    NASA Astrophysics Data System (ADS)

    Joblin, C.

    2010-07-01

    Far-ultraviolet (FUV) photons in massive OB star-forming regions have a major impact on the structure, dynamics, chemistry and thermal balance of their associated molecular cloud. We propose to study the photoevaporation under FUV irradiation of dense filaments in prototype photodissociation regions (PDR) by mapping with the HIFI spectrometer the [CII] 158 micron line associated with the evaporating gas and high-J CO lines tracing the warm dense structures. The combination of the spectral range covered by Herschel and the very high spectral resolution of HIFI is unique to get insight into the process of mixing of cold molecular gas into warm atomic gas. This process governs the evolution of dense gas submitted to FUV photons in a wide variety of astronomical objects including protostellar and protoplanetary disks but is best studied in PDRs. We ask for 9.8 hours of observations in two PDRs, NGC7023 and the Horsehead nebula. NGC7023 is illuminated by a B2Ve star and hosts very diluted atomic gas and dense filaments. The Horsehead nebula is a PDR viewed nearly edge-on with a high gas density gradient at the edge that is illuminated by a O9.5V star and is immersed in an HII region. In these objects, there is evidence for dynamical processes that create a mixing layer between molecular and atomic gas, both from gas kinematics (first results with HIFI on the [CII] line) and chemistry. The first HIFI [CII] results clearly call for a larger spatial coverage of the region using OTF mapping mode with HIFI to obtain a more complete picture of the PDR morphology and dynamics. The 12^CO(8-7) and 13^CO(8-7) lines will be also targeted to trace the warm interfaces of the dense filaments/edges. The team gathers together specialists of the studied regions and of the Herschel instruments: HIFI (this proposal), SPIRE and PACS (complementary data). The team has strong expertise in the study of the physics and chemistry of PDRs, both in terms of data analysis and modelling using and developing the Meudon PDR code.

  18. Time evolution of the optical spectra of the rubidium vapor zone produced by thermal evaporation in helium gas

    Microsoft Academic Search

    Mochizuki Shosuke

    1993-01-01

    The time evolution of the extinction spectra of the rubidium vapor zone has been measured after the beginning of gas evaporation. The structure of the spectra and their time dependence show the occurrence of atoms, dimers, clusters, and microcrystals. Also, they show a size trend in the surface plasma resonance frequency of rubidium clusters.

  19. Video-taped sample evaporation in hot chambers simulating gas chromatography split\\/splitless injectors

    Microsoft Academic Search

    Koni Grob; Maurus Biedermann

    2000-01-01

    The processes in devices imitating vaporising injectors were visualised and video-taped using perylene as a fluorescent marker for non-evaporated samples. The observations in the context of thermospray injection are summarised. Partial evaporation inside the needle turns the solvent into a propellant which nebulises the sample liquid at the needle exit. Evaporation in the vaporising chamber occurs from fine droplets suspended

  20. Estimation of evaporation at ungauged sites by combining ANFIS and Kriging methods

    NASA Astrophysics Data System (ADS)

    Chung, C.; Chiang, Y.; Chang, F.

    2010-12-01

    Eevaporation is one of the most essential references to management of agricultural irrigation. In this study, a hybrid model for estimating evaporation at any ungauged site was developed by combining the artificial neural network and the Kriging method. Data measured at nineteen meteorological gauging stations covering whole Taiwan in the period of 2007-2009 were collected, in which data of sixteen stations were used for model training and validation while data of the other three stations were adopted for testing the model’s accuracy at ungauged sites. First of all, the Adaptive Network-based Fuzzy Inference System (ANFIS) model was established for the estimation of evaporation. Second, the error between observation and ANFIS output was used for calculating the residual at ungauged sites by using Kriging with spatial interpolation. Finally, the evaporation estimation at ungauged sites can be achieved by summing up the ANFIS output and residual obtained from Kriging. The results showed that the combination of ANFIS and Kriging effectively improved evaporation estimation at ungauged sites as compared with Penman-Monteith formula, and provided an improvement of 17.2%, 22.5%, and 12.4%at northern, central, and southern Taiwan, respectively, in terms of RMSE. The model proposed in this study demonstrates its applicability and reliability in estimating evaporation at ungauged sites.

  1. Multielement analysis of groundwater samples by neutron activation with comparison between direct and evaporation methods

    Microsoft Academic Search

    Y. Kusaka; H. Tsuji; Y. Fujimoto; K. Ishida; Y. Fukui; T. Mamuro; T. Matsunami; A. Mizohata; S. Hirai

    1982-01-01

    This report is the results of the studies on NAA of groundwater samples with comparison between direct and evaporation methods,\\u000a and of the applications for the samples of alluvium plain composed with granitiform soils and of Neogene strata composed with\\u000a clay minerals.

  2. Numerical modeling of turbulent evaporating gas-droplet two-phase flows in an afterburner diffusor of turbo-fan jet engines

    NASA Astrophysics Data System (ADS)

    Zhou, Lixing; Zhang, Jian

    1990-11-01

    Two-dimensional turbulent evaporating gas-droplet two-phase flows in an afterburner diffusor of turbofan jet engines are simulated here by a k-epsilon turbulence model and a particle trajectory model. Comparison of predicted gas velocity and temperature distributions with experimental results for the cases without liquid spray shows good agreement. Gas-droplet two-phase flow predictions give plausible droplet trajectories, fuel-vapor concentration distribution, gas-phase velocity and temperature field in the presence of liquid droplets. One run of computation with this method is made for a particular afterburner. The results indicate that the location of the atomizers is not favorable to flame stabilization and combustion efficiency. The proposed numerical modeling can also be adopted for optimization design and performance evaluation of afterburner combustors of turbofan jet engines.

  3. Full evaporation dynamic headspace and gas chromatography-mass spectrometry for uniform enrichment of odor compounds in aqueous samples.

    PubMed

    Ochiai, Nobuo; Sasamoto, Kikuo; Hoffmann, Andreas; Okanoya, Kazunori

    2012-06-01

    A method for analysis of a wide range of odor compounds in aqueous samples at sub-ng mL?¹ to ?g mL?¹ levels was developed by full evaporation dynamic headspace (FEDHS) and gas chromatography-mass spectrometry (GC-MS). Compared to conventional DHS and headspace solid phase microextraction (HS-SPME), FEDHS provides more uniform enrichment over the entire polarity range for odor compounds in aqueous samples. FEDHS at 80°C using 3 L of purge gas allows complete vaporization of 100 ?L of an aqueous sample, and trapping and drying it in an adsorbent packed tube, while providing high recoveries (85-103%) of the 18 model odor compounds (water solubility at 25°C: log0.54-5.65 mg L?¹, vapor pressure at 25°C: 0.011-3.2 mm Hg) and leaving most of the low volatile matrix behind. The FEDHS-GC-MS method showed good linearity (r²>0.9909) and high sensitivity (limit of detection: 0.21-5.2 ng mL?¹) for the model compounds even with the scan mode in the conventional MS. The feasibility and benefit of the method was demonstrated with analyses of key odor compounds including hydrophilic and less volatile characteristics in beverages (whiskey and green tea). In a single malt whiskey sample, phenolic compounds including vanillin could be determined in the range of 0.92-5.1 ?g mL?¹ (RSD<7.4%, n=6). For a Japanese green tea sample, 48 compounds including 19 potent odorants were positively identified from only 100 ?L of sample. Heat-induced artifact formation for potent odorants was also examined and the proposed method does not affect the additional formation of thermally generated compounds. Eighteen compounds including 12 potent odorants (e.g. coumarin, furaneol, indole, maltol, and pyrazine congeners) were determined in the range of 0.21-110 ng mL?¹ (RSD<10%, n=6). PMID:22542289

  4. Measuring sub-canopy evaporation in a forested wetland using an ensemble of methods

    NASA Astrophysics Data System (ADS)

    Allen, S. T.; Edwards, B.; Reba, M. L.; Keim, R.

    2013-12-01

    Evaporation from the sub-canopy water surface is an integral but understudied component of the water balance in forested wetlands. Previous studies have used eddy covariance, energy balance approaches, and water-table fluctuations to assess whole-system evapotranspiration. However, partitioning evaporation from transpiration is necessary for modeling the system because of different controls over each process. Sub-canopy evaporation is a physically controlled process driven by relatively small gradients in residual energy transmitted through the canopy. The low-energy sub-canopy environment is characterized by a spatiotemporally varying light environment due to sunflecks, small and often inverse temperature and vapor gradients, and a high capacity for heat storage in flood water, which each present challenges to common evapotranspiration measurement techniques. Previous studies have examined wetland surface evaporation rates with small lysimeter experiments, but this approach does not encapsulate micrometeorological processes occurring at the scale of natural wetlands. In this study, we examine a one year time series of in situ sub-canopy flux measurements from a seasonally flooded cypress-tupelo swamp in southeast Louisiana. Our objective is to apply these data towards modeling sub-canopy energy flux responses to intra-annual hydrologic, phenologic, and climatic cycles. To assess and mitigate potential errors due to the inherent measurement challenges of this environment, we utilized multiple measurement approaches including eddy covariance, Bowen ratio energy balance (with both air to air gradients and water surface to air gradients) and direct measurement using a floating evaporation pan. Preliminary results show that Bowen ratio energy balance measurements are useful for constraining evaporation measurements when low wind speed conditions create a non-ideal setting for eddy covariance. However, Bowen ratios were often highly erratic due to the weak temperature and humidity gradients. This suggests the need to use combined methods during periods with problematic boundary layer conditions.

  5. ARE LARGE, COMETARY-SHAPED PROPLYDS REALLY (FREE-FLOATING) EVAPORATING GAS GLOBULES?

    SciTech Connect

    Sahai, R. [Jet Propulsion Laboratory, MS 183-900, California Institute of Technology, Pasadena, CA 91109 (United States); Guesten, R. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Morris, M. R., E-mail: raghvendra.sahai@jpl.nasa.gov [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095-1547 (United States)

    2012-12-20

    We report the detection of strong and compact molecular line emission (in the CO J = 3-2, 4-3, 6-5, 7-6, {sup 13}CO J = 3-2, HCN, and HCO{sup +} J = 4-3 transitions) from a cometary-shaped object (Carina-frEGG1) in the Carina star-forming region (SFR) previously classified as a photoevaporating protoplanetary disk (proplyd). We derive a molecular mass of 0.35 M{sub Sun} for Carina-frEGG1, which shows that it is not a proplyd, but belongs to a class of free-floating evaporating gas globules (frEGGs) recently found in the Cygnus SFR by Sahai et al. Archival adaptive optics near-IR (Ks) images show a central hourglass-shaped nebula. The derived source luminosity (about 8-18 L{sub Sun }), the hourglass morphology, and the presence of collimated jets seen in Hubble Space Telescope images imply the presence of a jet-driving, young, low-mass star deeply embedded in the dust inside Carina-frEGG1. Our results suggest that the true nature of many or most such cometary-shaped objects seen in massive SFRs and previously labeled as proplyds has been misunderstood, and that these are really frEGGs.

  6. Dynamics of transpiration and evaporation following a moisture pulse in semiarid grassland: A chamber-based isotope method for partitioning flux components

    Microsoft Academic Search

    Enrico A. Yepez; Travis E. Huxman; Danielle D. Ignace; Nathan B. English; Jake F. Weltzin; Alejandro E. Castellanos; David G. Williams

    2005-01-01

    We describe a novel method for partitioning evapotranspiration (ET) from isotopic measurements of water vapor within large (4.86m3) plot-scale gas exchange chambers. Using this approach, the short-term (15-day) dynamics of transpiration (T) and evaporation (E) in experimental replicated stands of the invasive grass Eragrostis lehmanniana and the native Heteropogon contortus were assessed following a 39-mm irrigation event in semiarid grassland

  7. Toward the Impact of Fuel Evaporation-Combustion Interaction on Spray Combustion in Gas Turbine Combustion Chambers. Part I: Effect of Partial Fuel Vaporization on Spray Combustion

    Microsoft Academic Search

    Amsini Sadiki; W. Ahmadi; Mouldi Chrigui; J. Janicka

    \\u000a This work aims at investigating the impact of the interaction between evaporation process and combustion on spray combustion\\u000a characteristics in gas turbine combustion chambers. It is subdivided into two parts. The first part studies how the evaporation\\u000a process affects the behavior of partially pre-vaporized spray combustion. The second part attempts to answer the question\\u000a how the fuel evaporation process behaves

  8. A comparison of methods for estimating open-water evaporation in small wetlands

    USGS Publications Warehouse

    Masoner, Jason R.; Stannard, David I.

    2010-01-01

    We compared evaporation measurements from a floating pan, land pan, chamber, and the Priestley-Taylor (PT) equation. Floating pan, land pan, and meteorological data were collected from June 6 to July 21, 2005, at a small wetland in the Canadian River alluvium in central Oklahoma, USA. Evaporation measured with the floating pan compared favorably to 12 h chamber measurements. Differences between chamber and floating pan rates ranged from ?0.2 to 0.3 mm, mean of 0.1 mm. The difference between chamber and land pan rates ranged from 0.8 to 2.0 mm, mean of 1.5 mm. The mean chamber-to-floating pan ratio was 0.97 and the mean chamber-to-land pan ratio was 0.73. The chamber-to-floating pan ratio of 0.97 indicates the use of a floating pan to measure evaporation in small limited-fetch water bodies is an appropriate and accurate method for the site investigated. One-sided Paired t-Tests indicate daily floating pan rates were significantly less than land pan and PT rates. A two-sided Paired t-Test indicated there was no significant difference between land pan and PT values. The PT equation tends to overestimate evaporation during times when the air is of low drying power and tends to underestimate as drying power increases.

  9. Gas-evaporation in low-gravity field (cogelation mechanism of metal vapors) (M-14)

    NASA Technical Reports Server (NTRS)

    Wada, N.

    1993-01-01

    When metal and alloy compounds are heated and vaporized in a rare gas such as helium, argon, or xenon, the vaporized substances diffused in the rare gas are supersaturated resulting in a smoke of fine particles of the material congealing as snow or fog. The gas vaporizing method is a fine particle generation method. Though the method has a variety of applications, the material vapor flow is disturbed by gravitational convection on Earth. The inability to elucidate the fine particle generation mechanism results in an obstruction to improving the method to mass production levels. As no convection occurs in microgravity in space, the fine particle generation mechanism influenced only by diffusion can be investigated. Investigators expect that excellent particles with homogeneous diameter distribution can be obtained. Experiment data and facts will assist in improving efficiency, quality, and scale or production processes including element processes such as vaporization, diffusion, and condensation. The objective of this experiment is to obtain important information related to the mechanism of particle formation in the gas atmosphere (smoke particles) and the production of submicron powders of extremely uniform size.

  10. A simplified reactive thermal evaporation method for indium tin oxide electrodes

    NASA Astrophysics Data System (ADS)

    Belo, G. S.; da Silva, B. J. P.; de Vasconcelos, E. A.; de Azevedo, W. M.; da Silva, E. F., Jr.

    2008-11-01

    Indium tin oxide (ITO) films approximately 120 nm thick were deposited onto unheated glass substrates by using reactive thermal evaporation (RTE) and in situ post-evaporation annealing in oxygen. We show that this simplified method can be used to produce high quality ITO thin films with low electrical resistivity (10 -3 ? cm) and high transmittance (approximately 80% at 550 nm). The refractive index is approximately 2.0 and the direct optical band gap of the films (above 3.0 eV) is in good agreement with previously reported values. Since this deposition method does not require heating the substrates or furnace annealing at high temperatures, it can be advantageous when it is necessary to decrease the thermal budget on underlying devices or layers.

  11. Crystal structures of small Al-rich Fe alloy particles formed by a gas-evaporation technique

    Microsoft Academic Search

    M. Tsuchimori; T. Ishimasa; Y. Fukano

    1992-01-01

    Crystal structures in small Al-rich Fe particles were studied by powder X-ray diffraction and transmission electron microscopy. The specimens of the small particles were made by evaporating an Al alloy material containing 5.0-33.3 at.% Fe in Xe gas at a pressure of 3.3 × 10 Pa. The small particles were 70-150 nm in diameter. In the particles, f.c.c. Al-Fe solid

  12. Diclofenac sodium-loaded solid lipid nanoparticles prepared by emulsion\\/solvent evaporation method

    Microsoft Academic Search

    Dongfei LiuSunmin; Sunmin Jiang; Hong Shen; Shan Qin; Juanjuan Liu; Qing Zhang; Rui Li; Qunwei Xu

    2011-01-01

    The preparation of solid lipid nanoparticles (SLNs) suffers from the drawback of poor incorporation of water-soluble drugs.\\u000a The aim of this study was therefore to assess various formulation and process parameters to enhance the incorporation of a\\u000a water-soluble drug (diclofenac sodium, DS) into SLNs prepared by the emulsion\\/solvent evaporation method. Results showed that\\u000a the entrapment efficiency (EE) of DS was

  13. Stability studies of biodegradable polymersomes prepared by emulsion solvent evaporation method

    Microsoft Academic Search

    Yuhan Lee; Jae-Byum Chang; Hong Kee Kim; Tae Gwan Park

    2006-01-01

    Di-block copolymers composed of two biocompatible polymers, poly(ethylene glycol) and poly(D,L-lactide), were synthesized\\u000a by ring-opening polymerization for preparing polymer vesicles (polymersomes). Emulsion solvent evaporation method was used\\u000a to fabricate the polymersomes. Scanning electron microscope (SEM) images confirmed that polymersomes have a hollow structure\\u000a inside. Confocal laser microscope and optical microscope were also used to verify the hollow structure of polymersomes.

  14. Characteristics of titanium oxide films deposited by an activated reactive evaporation method

    Microsoft Academic Search

    Tatsuo Fujii; Naoki Sakata; Jun Takada; Yoshinari Miura; Yoshihiro Daitoh; Mikio Takano

    1994-01-01

    Titanium di- and sesquioxide films were epitaxially grown on the (001) surface of sapphire single-crystalline substrates by an activated reactive evaporation method. Formation range for each titanium oxide was determined as a function of oxygen pressure (P(sub O2)) by means of x-ray diffraction, transmission electron microscopy, and Raman spectroscopy. Films prepared at P(sub O2)greater than or = 2.0 x 10(exp

  15. Studies on undoped SnO 2 thin film deposited by chemical reactive evaporation method

    Microsoft Academic Search

    J. B. Yadav; R. B. Patil; R. K. Puri; Vijaya Puri

    2007-01-01

    Transparent conducting undoped tin oxide thin film were prepared by chemical reactive evaporation method at various substrate temperature and post deposition heating for 30min. Structural, electrical, optical and mechanical properties were studied. The film showed direct band gap in the range of 3.12–3.28eV and the refractive index from 1.785 to 1.921. The minimum sheet resistance of ?243? was obtained at

  16. Sensing properties to dilute chlorine gas of indium oxide based thin film sensors prepared by electron beam evaporation

    Microsoft Academic Search

    Jun Tamaki; Chizuko Naruo; Yoshifumi Yamamoto; Masao Matsuoka

    2002-01-01

    Indium oxide based thin film sensors have been prepared by means of an electron beam evaporation and subjected to the detection of dilute Cl2 gas less than ppm-level. Among various In2O3 based sensors tested, the In2O3 thin film modified with Fe2O3 (1wt.%) showed extremely high sensitivity to dilute Cl2 gas of 0.2–5ppm. The Fe2O3–In2O3 sensor showed the sensitivity as high

  17. Shocked and Scorched - Free-Floating Evaporating Gas Globules and Star Formation

    NASA Astrophysics Data System (ADS)

    Sahai, Raghvendra; Morris, Mark R.; Claussen, Mark J.

    2014-07-01

    Massive stars have a strong feedback effect on their environment, via their winds, UV radiation, and ultimately, supernova blast waves, all of which can alter the likelihood for the formation of stars in nearby clouds and limit the accretion process of nearby protostars. Free-floating Evaporating Gaseous Globules, or frEGGs, are a newly recognized class of stellar nurseries embedded within the giant HII regions found in massive star-formation region (MSFRs). We recently discovered the prototype frEGG in the Cygnus MSFR with HST. Further investigation using the Spitzer and Herschel archives have revealed a much larger number (>50) in Cygnus and other MSFRs. Our molecular-line observations of these show the presence of dense clouds with total masses of cool molecular gas exceeding 0.5 to a few Msun associated with these objects, thereby disproving the initial hypothesis based on their morphology that these have an origin similar to the proplyds (cometary-shaped photoevaporating protoplanetary disks) found in Orion. We report the results of our molecular-line studies and detailed high-resolution optical (with HST) or near-IR (with AO at the Keck Observatory) imaging of a few frEGGs in Cygnus, Carina and the W5 MSFRs. The images show the presence of young stars with associated outflow cavities and/or jets in the heads of the tadpole-shaped frEGGs. These results support our hypothesis that frEGGs are density concentrations originating in giant molecular clouds, that, when subject to the compression by the strong winds and ionization from massive stars in these MSFRs, become active star-forming cores. In summary, by virtue of their distinct, isolated morphologies, frEGGs offer us a clean probe of triggered star formation on small scales in the vicinity of massive stars.

  18. Controllable two-stage droplet evaporation method and its nanoparticle self-assembly mechanism.

    PubMed

    Xie, Yong; Guo, Shengming; Guo, Chuanfei; He, Meng; Chen, Dongxue; Ji, Yinglu; Chen, Ziyu; Wu, Xiaochun; Liu, Qian; Xie, Sishen

    2013-05-28

    Bottom-up self-assembly is able to constitute a variety of structures and has been thought to be a promising way for advanced nanofabrication. Droplet evaporation, as the simplest method, has been used in various self-assemblies. However, the assembled area is not large enough and the order is still not well controlled. Here we show a facile and controllable two-stage droplet evaporation method by adjusting the humidity and temperature of the evaporating droplet. Taking the highly monodispersed gold nanorods (GNRs) as an example, large-area, self-assembly monolayer arrays are reproducibly achieved. To understand the self-assembly mechanism, we adopted simplified models to analyze the interactions between the nanorods. The results show that a metastable state of secondary-energy-minimum exists, especially in the latter stage of the assembly process, leading to the ordered arrays. A large electrostatic barrier between the assembled arrays prevents the formation of the multilayer structures and thereby leads to the preferential monolayers. Moreover, we predict possibilities of different types of assemblies of the nanorods, and a schematic phase diagram is finally given. The results here may offer a way toward high-quality self-assembled nanoparticles superlattices for use in enhanced spectroscopy, sensors, or nanodevices. PMID:23672308

  19. The preparation of accelerator targets by the evaporation of acetate-organic solutions in the presence of NH/sub 3/ gas

    SciTech Connect

    Cai, S.Y.; Ghiorso, A.; Hoffman, D.C.

    1987-03-01

    The chemical methods described in this paper have been developed for preparation of isotopic targets for bombardment by accelerator-produced ions. Three systems are compared: nitrate-, chloride-, and acetate-organic solutions. The best method was found to be the metallic acetate-organic solution system, evaporated onto the substrate in the presence of ammonia gas. A detailed procedure is given for this method. The targets obtained by the acetate-organic solution system are uniform and adherent. The hydroxide forms fine crystals of good quality for target thicknesses from a few ..mu..g/cm/sup 2/ to several mg/cm/sup 2/. Thicknesses up to 5 mg/cm/sup 2/ of Eu as the oxide were obtained by this method. The process is simple and fast. 18 refs., 1 tab.

  20. Atmospheric pressure matrix-assisted laser desorption ionization as a plume diagnostic tool in laser evaporation methods

    E-print Network

    Vertes, Akos

    Atmospheric pressure matrix-assisted laser desorption ionization as a plume diagnostic tool introduced analytical method, atmospheric pressure matrix-assisted laser desorption ionization (AP- MALDI write; Atmospheric pressure MALDI; Laser evaporation; Plume diagnostics 1. Introduction Diagnostics

  1. Method for hot gas conditioning

    DOEpatents

    Paisley, Mark A. (Upper Arlington, OH)

    1996-02-27

    A method for cracking and shifting a synthesis gas by the steps of providing a catalyst consisting essentially of alumina in a reaction zone; contacting the catalyst with a substantially oxygen free mixture of gases comprising water vapor and hydrocarbons having one or more carbon atoms, at a temperature between about 530.degree. C. (1000.degree. F.) to about 980.degree. C. (1800.degree. F.); and whereby the hydrocarbons are cracked to form hydrogen, carbon monoxide and/or carbon dioxide and the hydrogen content of the mixture increases with a corresponding decrease in carbon monoxide, and carbon formation is substantially eliminated.

  2. Preparation and growth mechanism of ?-SiC nanowires by using a simplified thermal evaporation method

    NASA Astrophysics Data System (ADS)

    Liu, Haitao; Huang, Zhaohui; Fang, Minghao; Liu, Yan-gai; Wu, Xiaowen

    2015-06-01

    ?-SiC nanowires were synthesized by using an improved simple and low-cost thermal evaporation process at 1500 °C, without argon protect and catalyst assistant. The process simplifies the chemical vapor deposition method, which makes it easier to operate and industrialize. X-ray diffraction, Field emission scanning electron microscopy, high-resolution transmission electron microscopy and energy dispersive spectrum were employed to characterize the as-synthesized products. The ?-SiC nanowires are about 50-100 nm in diameter, up to several micrometers long and usually grow along [111] direction with a thin oxide shell. A vapor-solid growth mechanism of the nanowires is proposed.

  3. Preparation of AgInSe2 thin films grown by vacuum evaporation method

    NASA Astrophysics Data System (ADS)

    Matsuo, H.; Yoshino, K.; Ikari, T.

    2006-09-01

    Polycrystalline AgInSe2 thin films were successfully grown on glass substrates by an evaporation method. The starting materials were stoichiometrically mixed Ag2Se and In2Se3 powders. X-ray diffraction revealed that the sample annealed at 600 °C consisted of AgInSe2 single phase, with (112) orientation and a large grain size. The lattice constant (a axis) was close to JCPDS values. From optical transmittance and reflectance measurements, the bandgap energy was estimated to be 1.17 eV.

  4. Video-taped sample evaporation in hot chambers simulating gas chromatography split and splitless injectors

    Microsoft Academic Search

    Koni Grob; Maurus Biedermann

    2000-01-01

    The processes in devices imitating a vaporising injector were video-taped using perylene as a fluorescent marker for non-evaporated sample. Processes are summarised which are observed after the sample liquid passed through a cool needle and left as a band of liquid moving at high velocity (as typical for injection by fast autosamplers). This liquid is shot past the column entrance

  5. Gas-phase saturation and evaporative cooling effects during wet compression of a fuel aerosol under RCM conditions

    SciTech Connect

    Goldsborough, S.S. [Department of Mechanical Engineering, Marquette University, Milwaukee, WI (United States); Johnson, M.V. [Energy Systems Division, Argonne National Laboratory, IL (United States); Zhu, G.S. [HDEP Performance and Emissions, DTNA - Detroit Diesel Corporation, Detroit, MI (United States); Aggarwal, S.K. [Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, 1030 Engineering Research Facility, Chicago, IL (United States)

    2011-01-15

    Wet compression of a fuel aerosol has been proposed as a means of creating gas-phase mixtures of involatile diesel-representative fuels and oxidizer + diluent gases for rapid compression machine (RCM) experiments. The use of high concentration aerosols (e.g., {proportional_to}0.1 mL{sub fuel}/L{sub gas}, {proportional_to}1 x 10{sup 9} droplets/L{sub gas} for stoichiometric fuel loading at ambient conditions) can result in droplet-droplet interactions which lead to significant gas-phase fuel saturation and evaporative cooling during the volumetric compression process. In addition, localized stratification (i.e., on the droplet scale) of the fuel vapor and of temperature can lead to non-homogeneous reaction and heat release processes - features which could prevent adequate segregation of the underlying chemical kinetic rates from rates of physical transport. These characteristics are dependent on many factors including physical parameters such as overall fuel loading and initial droplet size relative to the compression rate, as well as fuel and diluent properties such as the boiling curve, vaporization enthalpy, heat capacity, and mass and thermal diffusivities. This study investigates the physical issues, especially fuel saturation and evaporative cooling effects, using a spherically-symmetric, single-droplet wet compression model. n-Dodecane is used as the fuel with the gas containing 21% O{sub 2} and 79% N{sub 2}. An overall compression time and compression ratio of 15.3 ms and 13.4 are used, respectively. It is found that smaller droplets (d{sub 0}{proportional_to} 2-3 {mu}m) are more affected by 'far-field' saturation and cooling effects, while larger droplets (d{sub 0}{proportional_to} 14 {mu}m) result in greater localized stratification of the gas-phase due to the larger diffusion distances for heat and mass transport. Vaporization of larger droplets is more affected by the volumetric compression process since evaporation requires more time to be completed even at the same overall fuel loading. All of the cases explored here yield greater compositional stratification than thermal stratification due to the high Lewis numbers of the fuel-air mixtures (Le{sub g} {proportional_to} 3.8). (author)

  6. Reviving the Bowen Ratio method for Actual Evaporation with Distributed Temperature Sensing

    NASA Astrophysics Data System (ADS)

    Luxemburg, W. M. J.; Euser, T.; Everson, C. S.; Mengistu, M. G.; Clulow, A. D.

    2012-04-01

    We have used the technique of distributed temperature sensing (DTS) with a fiber optic cable to determine actual evaporation over land. The results were compared with measurements using a surface layer scintilometer, surface renewal and eddy covariance techniques. Dry and wetted sections of a fiber optic cable were suspended from a six meter high tower in a sugar beet trial in KwaZulu-Natal, South Africa. From the principle of a psychrometer, a near continuous observation of vapor pressure and temperature at 0.20 m intervals of a vertical column of air above the field could be derived. Subsequently it allowed accurate determination of the ratio of sensible and latent heat, i.e. the Bowen ratio over time and in the vertical. Using measurements of the net radiation, soil heat flux and the Bowen ratio sensible heat flux, the actual evaporation could be determined as the residual of the shortened energy balance equation. The advantage of the DTS method over the traditional Bowen ratio method is that one and the same sensor (the fiber optic cable) is used, with sufficient accuracy to discriminate small differences in temperature and vapor pressure respectively, hence giving numerous gradient measurements over the vertical. The traditional Bowen ratio method relies on only a few sensors that require careful calibration to detect the real differences of temperature and vapor pressure. Comparing the improved method with the traditional Bowen Ratio method, shows that the improved method gives more stable and constant results than the standard method. The DTS data were reliable, provided that water blown by strong wind from the wetted cable does not affect the temperature of air at the location of the dry cable. Under these conditions the vertical air temperature was not representative for the air temperature over the fetch of the crop. The experiments were carried out in South Africa, in November 2011 (summer) under varying radiation conditions. In this way it was demonstrated that direct exposure of the fiber optic cable to these high radiative conditions (max incoming short wave radiation = 900 w/m^2) had no noticeable effect on the evaporation results.

  7. Nanoprecipitation is more efficient than emulsion solvent evaporation method to encapsulate cucurbitacin I in PLGA nanoparticles.

    PubMed

    Alshamsan, Aws

    2014-07-01

    Cucurbitacin I is a hydrophobic molecule that exerts a degree of polarity, which is expected to complicate its loading in PLGA nanoparticles by the classical emulsion solvent evaporation technique. In the current study, variants of emulsion solvent evaporation method were used to prepare PLGA nanoparticles of cucurbitacin: CI-NP1 (single emulsion starting with 1000 ?g drug), CI-NP2 (double emulsion starting with 250 ?g drug), and CI-NP3 (double emulsion starting with 500 ?g drug). On the other hand, CI-NP4 was prepared by nanoprecipitation (starting with 1000 ?g drug). In CI-NP1, cucurbitacin I encapsulation efficiency (EE) was 1.29%. The employment of double emulsion, in CI-NP2 and CI-NP3, increased cucurbitacin I EE to 4.8% and 7.96%, respectively. Nanoprecipitation significantly increased the EE of cucurbitacin I to 48.79% in CI-NP4. It is likely that cucurbitacin I escapes with the organic solvent after the emulsification step to the aqueous phase leading to ineffective entrapment in the polymeric matrix. Avoiding emulsification seems efficient in increasing cucurbitacin I disposition in the instantly-precipitating NPs. Therefore, nanoprecipitation method increases cucurbitacin I entrapment in PLGA NPs and possibly other water-insoluble polar drugs. PMID:25061407

  8. Ultrafine powders of TiN and AlN produced by a reactive gas evaporation technique with electron beam heating

    NASA Astrophysics Data System (ADS)

    Iwama, Saburo; Hayakawa, Kenji; Arizumi, Tetsuya

    1982-01-01

    Ultrafine powders of TiN and AlN are produced by evaporating Ti and Al in a low pressure of NH 3 or N 2 gas by using electron beam heating. Powders produced are studied by means of electron microscopy and X-ray diffraction method. Both powders are confirmed to be pure nitride with cubic crystal structure for TiN and hexagonal for AlN, and to have a particle size less than 10 nm. The formation process of the nitride powder by the present method can be summarized as follows; (1) surface nitridation of the source materials, (2) vaporization of the nitride and (3) condensation into the nitride particles.

  9. Hydrogen-gas-laser method and apparatus

    Microsoft Academic Search

    D. Brandt; C. Ottinger

    1979-01-01

    The specification describes a method for pumping molecular hydrogen in a hydrogen laser. The pumping is carried out via noble gas atoms which are in a metastable state of excitation and preferably ionized. A hydrogen laser operating in accordance with this method comprises a gas filling including molecular hydrogen as a laser medium and at least one noble gas, preferably

  10. Determination of clothing evaporative resistance on a sweating thermal manikin in an isothermal condition: heat loss method or mass loss method?

    PubMed

    Wang, Faming; Gao, Chuansi; Kuklane, Kalev; Holmér, Ingvar

    2011-08-01

    This paper addresses selection between two calculation options, i.e heat loss option and mass loss option, for thermal manikin measurements on clothing evaporative resistance conducted in an isothermal condition (T(manikin) = T(a) = T(r)). Five vocational clothing ensembles with a thermal insulation range of 1.05-2.58 clo were selected and measured on a sweating thermal manikin 'Tore'. The reasons why the isothermal heat loss method generates a higher evaporative resistance than that of the mass loss method were thoroughly investigated. In addition, an indirect approach was applied to determine the amount of evaporative heat energy taken from the environment. It was found that clothing evaporative resistance values by the heat loss option were 11.2-37.1% greater than those based on the mass loss option. The percentage of evaporative heat loss taken from the environment (H(e,env)) for all test scenarios ranged from 10.9 to 23.8%. The real evaporative cooling efficiency ranged from 0.762 to 0.891, respectively. Furthermore, it is evident that the evaporative heat loss difference introduced by those two options was equal to the heat energy taken from the environment. In order to eliminate the combined effects of dry heat transfer, condensation, and heat pipe on clothing evaporative resistance, it is suggested that manikin measurements on the determination of clothing evaporative resistance should be performed in an isothermal condition. Moreover, the mass loss method should be applied to calculate clothing evaporative resistance. The isothermal heat loss method would appear to overestimate heat stress and thus should be corrected before use. PMID:21669906

  11. Synthesis gas method and apparatus

    DOEpatents

    Kelly, Sean M.; Kromer, Brian R.; Litwin, Michael M.; Rosen, Lee J.; Christie, Gervase Maxwell; Wilson, Jamie R.; Kosowski, Lawrence W.; Robinson, Charles

    2013-01-08

    A method and apparatus for producing a synthesis gas product having one or more oxygen transport membrane elements thermally coupled to one or more catalytic reactors such that heat generated from the oxygen transport membrane element supplies endothermic heating requirements for steam methane reforming reactions occurring within the catalytic reactor through radiation and convention heat transfer. A hydrogen containing stream containing no more than 20 percent methane is combusted within the oxygen transport membrane element to produce the heat and a heated combustion product stream. The heated combustion product stream is combined with a reactant stream to form a combined stream that is subjected to the reforming within the catalytic reactor. The apparatus may include modules in which tubular membrane elements surround a central reactor tube.

  12. Gas flow meter and method for measuring gas flow rate

    DOEpatents

    Robertson, Eric P.

    2006-08-01

    A gas flow rate meter includes an upstream line and two chambers having substantially equal, fixed volumes. An adjustable valve may direct the gas flow through the upstream line to either of the two chambers. A pressure monitoring device may be configured to prompt valve adjustments, directing the gas flow to an alternate chamber each time a pre-set pressure in the upstream line is reached. A method of measuring the gas flow rate measures the time required for the pressure in the upstream line to reach the pre-set pressure. The volume of the chamber and upstream line are known and fixed, thus the time required for the increase in pressure may be used to determine the flow rate of the gas. Another method of measuring the gas flow rate uses two pressure measurements of a fixed volume, taken at different times, to determine the flow rate of the gas.

  13. Novel in situ method for locating virtual source in high-rate electron-beam evaporation

    NASA Astrophysics Data System (ADS)

    Bhatia, M. S.

    1994-07-01

    The concept of virtual source simplifies calculation of thickness distribution on extended substrates in high rate vacuum coating employing electron-beam heating. The height of the point (virtual source), from which vapor can be assumed to emanate in accordance with Knudsen's cosine law, to yield the experimentally obtained thickness distribution, is calculated and this establishes the position of virtual source. Such as post facto determination is cumbersome as it is valid for the prescribed material evaporating at a certain rate in a specified geometry. A change in any of these entails a fresh measurement. Experimenters who use a large number of materials and deposit at different rates therefore have to carry out a number of trials before they can locate the virtual source at the desired deposition parameters. An in situ method for obtaining virtual source position can go a long way in reducing the labor of these experiments. A novel in situ method is described to locate the virtual source.

  14. Kinetic boundary layers in gas mixtures: Systems described by nonlinearly coupled kinetic and hydrodynamic equations and applications to droplet condensation and evaporation

    SciTech Connect

    Widder, M.E.; Titulaer, U.M. (Johannes-Kepler-Universitaet Linz (Austria))

    1993-03-01

    The authors consider a mixture of heavy vapor molecules and a light carrier gas surrounding a liquid droplet. The vapor is described by a variant of the Klein-Kramers equation; the gas is described by the Navier-Stokes equations; the droplet acts as a heat source due to the released heat of condensation. The exchange of momentum and energy between the constituents of the mixture is taken into account by force terms in the kinetic equation and source terms in the Navier-Stokes equations. These are chosen to obtain maximal agreement with the irreversible thermodynamics of a gas mixture. The structure of the kinetic boundary layer around the sphere is determined from the self-consistent solution of this set of coupled equations with appropriate boundary conditions at the surface of the sphere. The kinetic equation is rewritten as a set of coupled moment equations. A complete set of solutions of these moment equations is constructed by numerical integration inward from the region far away from the droplet, where the background inhomogeneities are small. A technique developed earlier is used to deal with the numerical instability of the moment equations. The solutions obtained for given temperature and pressure profiles in the gas are then combined linearly such that they obey the boundary conditions at the droplet surface; from this solution source terms for the Navier-Stokes equation of the gas are constructed and used to determine improved temperature and pressure profiles for the background gas. For not too large temperature differneces between the droplet and the gas at infinity, self-consistency is reached after a few iterations. The method is applied to the condensation of droplets from a supersaturated vapor as well as to strong evaporation of droplets under the influence of an external heat source, where corrections of up to 40% are obtained.

  15. Evaluation of the energy budget method of determining evaporation at Williams Lake, Minnesota, using alternative instrumentation and study approaches

    USGS Publications Warehouse

    Rosenberry, D.O.; Sturrock, A.M.; Winter, T.C.

    1993-01-01

    Best estimates of evaporation were determined by the energy budget method using optimum sensors and optimum placement of sensors. For most of the data substitutions that affected the Bowen ratio, new values of evaporation differed little from best estimates. The three data substitution methods that caused the largest deviations from the best evaporation estimates were (1) using changes in the daily average surface water temperature as an indicator of the lake heat storage term, (2) using shortwave radiation, air temperature, and atmospheric vapor pressure data from a site 110 km away, and (3) using an analog surface water temperature probe. Recalculations based on these data substitutions resulted in differences from the best estimates as much as 89%, 21% and 10%, respectively. The data substitution method that provided evaporation values that most closely matched the best estimates was measurement of the lake heat storage term at one location in the lake, rather than at 16 locations. Evaporation values resulting from this substitution method usually were within 2% of the best estimates. -from Authors

  16. Evaporation of acoustically levitated multi-component liquid droplets

    Microsoft Academic Search

    G. Brenn; L. J. Deviprasath; F. Durst; C. Fink

    2007-01-01

    A theoretical model for the evaporation of multi-component liquid droplets based on the model by Abramzon and Sirignano is presented and applied to the evaporation of acoustically levitated droplets. The liquid phase is treated as a thermodynamically real fluid, using the UNIFAC method for calculating the component activities, and the gas phase as ideal. Computational results, which consist in the

  17. Optical Properties of CdS Nanobelts and Nanosaws Synthesized by Thermal Evaporation Method

    NASA Astrophysics Data System (ADS)

    Peng, Zhi-wei; Zou, Bing-suo

    2012-04-01

    By a simple one-step H2-assisted thermal evaporation method, high quality CdS nanostructures have been successfully fabricated on Au coated Si substrates in large scale. The as-synthesized CdS nanostructures consisted of sword-like nanobelts and toothed nanosaws with a single-crystal hexagonal wurtzite structure. The deposition temperature played an important role in determining the size and morphology of the CdS nanostructures. A combination of vapor-liquid-solid and vapor-solid growth mechanisms were proposed to interpret the formation of CdS nanostructures. Photoluminescence measurement indicated that the nanobelts and nanosaws have a prominent green emission at about 512 nm, which is the band-to-band emission of CdS. The waveguide characteristics of both types of CdS nanostructures were observed and discussed.

  18. Cationic Eudragit® polymers as excipients for microparticles prepared by solvent evaporation method.

    PubMed

    Vysloužil, Jakub; Bavo?árová, Jana; Kejdušová, Martina; Vetchý, David; Dvo?á?ková, Kate?ina

    2013-12-01

    Three cationic acrylic polymers, i. e. Eudragit® RL, Eudragit® RS and Eudragit® E 100, were evaluated for the purpose of microparticles preparation by the solvent evaporation method. The practically insoluble drug mirtazapine and the freely soluble drug tramadol hydrochloride were selected for encapsulation as extreme limits of drug solubility. The prepared microspheres were analyzed by optical microscopy, drug content analysis and dissolution test. It was observed that Eudragit® RL did not provide microparticles while Eudragit® RS and Eudragit® E 100 yielded spherical microparticles. Samples prepared with mirtazapine showed sustained drug release whereas tramadol hydrochloride samples released the drug in a pattern similar to the immediate release profile. Eudragit® RS was found to be superior to Eudragit® E 100 in its encapsulation efficiency, drug loading and smaller mean size of microparticles. PMID:24393112

  19. Size-velocity correlations in high order moment methods for polydisperse evaporating sprays: modeling and numerical issues

    E-print Network

    Paris-Sud XI, Université de

    Size-velocity correlations in high order moment methods for polydisperse evaporating sprays developed the Eulerian Multi-Size Moment model (EMSM) which tackles the modeling and numerical simulation and realizable NDF, potentially in several size intervals, thus leading to an hybrid method between Multifluid

  20. Method for the evaporation of a liquid solution using mechanical compression

    SciTech Connect

    Eversdijk, B.P.

    1984-02-28

    A liquid solution is passed through a multi-stage evaporation plant while using recirculated vapor, fed through a mechanical compressor in order to increase the pressure and temperature of the vapor. The plant comprises a number of evaporators connected in series and split up into a plurality of groups, which comprise a decreasing number of evaporators; as seen in the flow direction-the vapor being fed in parallel, streams through said groups.

  1. Group evaporation

    NASA Technical Reports Server (NTRS)

    Shen, Hayley H.

    1991-01-01

    Liquid fuel combustion process is greatly affected by the rate of droplet evaporation. The heat and mass exchanges between gas and liquid couple the dynamics of both phases in all aspects: mass, momentum, and energy. Correct prediction of the evaporation rate is therefore a key issue in engineering design of liquid combustion devices. Current analytical tools for characterizing the behavior of these devices are based on results from a single isolated droplet. Numerous experimental studies have challenged the applicability of these results in a dense spray. To account for the droplets' interaction in a dense spray, a number of theories have been developed in the past decade. Herein, two tasks are examined. One was to study how to implement the existing theoretical results, and the other was to explore the possibility of experimental verifications. The current theoretical results of group evaporation are given for a monodispersed cluster subject to adiabatic conditions. The time evolution of the fluid mechanic and thermodynamic behavior in this cluster is derived. The results given are not in the form of a subscale model for CFD codes.

  2. Synthesis and optical properties of zinc oxide nanoparticles grown on Sn-coated silicon substrate by thermal evaporation method

    NASA Astrophysics Data System (ADS)

    Somvanshi, Divya; Jit, S.

    2013-01-01

    The Zinc oxide (ZnO) nanoparticles have been grown on n type silicon substrate using tin (Sn) metal as seed layer by a low cost thermal evaporation method. SEM images show that the ZnO nanoparticles have been uniformely grown on the whole substrate surface relatively perpendicular to the substrate. The Photoluminescence (PL) spectrum consists of strong UV emission at wavelength of 355 nm along with a broad near band edge (NBE) emission covering a wide range of wavelength from 370 to 550 nm. This broadening region exhibits blue, violet and green emission due to the presence of native defects such as zinc interstitial (Zni), oxygen vacancy (VO) and oxygen interstitial (Oi) in the band gap of ZnO. Raman spectroscopy shows the existence of E2 mode at 437 cm-1 which confirms the pure wurtzite hexagonal phase of ZnO. The optical and structural properties of ZnO nanoparticles could be explored for blue-violet light emitting diodes (LEDs) and gas sensing applications.

  3. Analysis of gas production methods for methane gas hydrate reservoirs

    NASA Astrophysics Data System (ADS)

    Ivakhnenko, Aleksandr; Baluanov, Bakhytzhan; Shopenova, Aigerim; Gulnur, Asan; Agzomova, Bagdagul

    2015-04-01

    In methane gas hydrate reservoir (MH), pressure and temperature conditions are in the MH stability region in the initial stage. To dissociate MH and produce gas from a MH reservoir, pressure and temperature conditions should be moved to the dissociation region. Therefore, three methods of depressurization, thermal and inhibitor injection have been modeled and analyzed as a basic methods for different conditions that might occur in nature. Furthermore, several methods such as injection of gas other than methane and irradiation of ultrasonic wave were also investigated especially for the MH dissociation and possible gas production. The simulation results allowed to select optimal screening approach for the appropriate production method that can be employed in specific MH conditions.

  4. Could CoRoT-7b and Kepler-10b be remnants of evaporated gas or ice giants?

    PubMed Central

    Leitzinger, M.; Odert, P.; Kulikov, Yu.N.; Lammer, H.; Wuchterl, G.; Penz, T.; Guarcello, M.G.; Micela, G.; Khodachenko, M.L.; Weingrill, J.; Hanslmeier, A.; Biernat, H.K.; Schneider, J.

    2011-01-01

    We present thermal mass loss calculations over evolutionary time scales for the investigation if the smallest transiting rocky exoplanets CoRoT-7b (?1.68REarth) and Kepler-10b (?1.416REarth) could be remnants of an initially more massive hydrogen-rich gas giant or a hot Neptune-class exoplanet. We apply a thermal mass loss formula which yields results that are comparable to hydrodynamic loss models. Our approach considers the effect of the Roche lobe, realistic heating efficiencies and a radius scaling law derived from observations of hot Jupiters. We study the influence of the mean planetary density on the thermal mass loss by placing hypothetical exoplanets with the characteristics of Jupiter, Saturn, Neptune, and Uranus to the orbital location of CoRoT-7b at 0.017 AU and Kepler-10b at 0.01684 AU and assuming that these planets orbit a K- or G-type host star. Our findings indicate that hydrogen-rich gas giants within the mass domain of Saturn or Jupiter cannot thermally lose such an amount of mass that CoRoT-7b and Kepler-10b would result in a rocky residue. Moreover, our calculations show that the present time mass of both rocky exoplanets can be neither a result of evaporation of a hydrogen envelope of a “Hot Neptune” nor a “Hot Uranus”-class object. Depending on the initial density and mass, these planets most likely were always rocky planets which could lose a thin hydrogen envelope, but not cores of thermally evaporated initially much more massive and larger objects. PMID:21969736

  5. Low temperature and self catalytic growth of ultrafine ITO nanowires by electron beam evaporation method and their optical and electrical properties

    SciTech Connect

    Kumar, R. Rakesh, E-mail: rakesh.rajaboina@gmail.com [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012 (India); Department of Physics, Indian Institute of Science Education and Research, Bhopal 462066 (India); Rao, K. Narasimha; Rajanna, K. [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012 (India); Phani, A.R. [Nano-Research for Advanced Materials and Technologies, Bangalore 560040 (India)

    2014-04-01

    Highlights: • ITO nanowires were grown by e-beam evaporation method. • ITO nanowires growth done at low substrate temperature of 350 °C. • Nanowires growth was carried out without use of catalyst and reactive oxygen gas. • Nanowires growth proceeds via self catalytic VLS growth. • Grown nanowires have diameter 10–20 nm and length 1–4 ?m long. • ITO nanowire films have shown good antireflection property. - Abstract: We report the self catalytic growth of Sn-doped indium oxide (ITO) nanowires (NWs) over a large area glass and silicon substrates by electron beam evaporation method at low substrate temperatures of 250–400 °C. The ITO NWs growth was carried out without using an additional reactive oxygen gas and a metal catalyst particle. Ultrafine diameter (?10–15 nm) and micron long ITO NWs growth was observed in a temperature window of 300–400 °C. Transmission electron microscope studies confirmed single crystalline nature of the NWs and energy dispersive spectroscopy studies on the NWs confirmed that the NWs growth proceeds via self catalytic vapor-liquid-solid (VLS) growth mechanism. ITO nanowire films grown on glass substrates at a substrate temperature of 300–400 °C have shown ?2–6% reflection and ?70–85% transmission in the visible region. Effect of deposition parameters was systematically investigated. The large area growth of ITO nanowire films would find potential applications in the optoelectronic devices.

  6. Fabrication and characterization of bismuth–telluride-based alloy thin film thermoelectric generators by flash evaporation method

    Microsoft Academic Search

    M. Takashiri; T. Shirakawa; K. Miyazaki; H. Tsukamoto

    2007-01-01

    Bismuth–telluride-based alloy thin film thermoelectric generators are fabricated by a flash evaporation method. We prepare Bi0.4Te3.0Sb1.6 (p-type) and Bi2.0Te2.7Se0.3 (n-type) powders for the fabrication of the flash evaporated thin films. The overall size of the thin film thermoelectric generators, which consist of seven pairs of legs connected by aluminum electrodes, is 20mm by 15mm. Each leg is 15mm long, 1mm

  7. Cellular uptake of beta-carotene from protein stabilized solid lipid nano-particles prepared by homogenization-evaporation method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a homogenization-evaporation method, beta-carotene (BC) loaded nano-particles were prepared with different ratios of food-grade sodium caseinate (SC), whey protein isolate (WPI), or soy protein isolate (SPI) to BC and evaluated for their physiochemical stability, in vitro cytotoxicity, and cel...

  8. Prediction of chilling times of foods in situations where evaporative cooling is significant—Part 1. Method development

    Microsoft Academic Search

    Sawitri Chuntranuluck; C. M. Wells; A. C. Cleland

    1998-01-01

    The finite difference method was used to simulate the unsteady state cooling of spheres, infinite slabs and infinite cylinders of food materials subject to both convection and evaporation at the product surface. Simulations were conducted across wide ranges of air temperature, surface heat transfer coefficient, product initial temperature, surface water activity and air relative humidity. Algebraic equations are proposed for

  9. Development and Physicochemical Characterization of Sirolimus Solid Dispersions Prepared by Solvent Evaporation Method

    PubMed Central

    Emami, Shahram; Valizadeh, Hadi; Islambulchilar, Ziba; Zakeri-Milani, Parvin

    2014-01-01

    Purpose: The aim of the present investigation was preparation and characterization of sirolimus solid dispersions by solvent evaporation technique to improve its dissolution properties. Methods: Polyvinylpyrrolidone (PVP), Poloxamer 188 and Cremophore RH40 were used to prepare the solid dispersions of sirolimus. In vitro dissolution study using USP type I apparatus, were performed in distilled water (containing SLS 0.4%) for pure sirolimus, physical mixtures, Rapamune and prepared solid dispersions. The characterization of solid dispersions was performed using Fourier Transform Infrared (FTIR) Spectroscopy and Differential Scanning Calorimetry (DSC). Results: More than 75% of sirolimus was released within 30 minutes from all prepared solid dispersions. The dissolution rate of all prepared solid dispersion powders were more than physical mixtures. The absence of sirolimus peak in the DSC spectrum of solid dispersions indicated the conversion of crystalline form of sirolimus into amorphous form. The results from FT-IR spectroscopy showed that there was no significant change in the FT-IR spectrum of solid dispersions indicating absence of well-defined interaction between drug and carriers. Conclusion: It was concluded that solid dispersion method, using PVP, Poloxamer 188 and Cremophore RH40 can improve dissolution rate of sirolimus. PMID:25436193

  10. Water retention curves of loamy-sandy soils: Transient evaporation method versus steady-state tension and pressure techniques

    NASA Astrophysics Data System (ADS)

    Winkler, G.; Eberhard, E.; Fank, J.; Birk, S.

    2009-12-01

    Water retention curves of loamy-sandy soils at the agricultural test site Wagna (Austria) were measured using both the simplified evaporation method according to Schindler (Arch. Acker- u. Pflanzenbau u. Bodenkd. Berlin 24, 1-7, 1980) and steady-state tension and pressure techniques. The soil was sampled with 250-ccm and 100-ccm steel pipes for the evaporation method and the steady-state technique, respectively. In the transient evaporation method two tensiometers with a measurement range between 0 and 850 hPa are installed at a depth of 1.25 cm and 3.75 cm in a sample of 5 cm in height; the mean values of the two tensiometers and the water contents measured by weighing are used to obtain the water retention curve. The steady-state method employs a tension table (sand box) at tensions below 100 hPa and a pressure extractor at tensions between 300 hPa and 15,000 hPa; the water content is measured by weighing after the sample has equilibrated at the tension value set on the table or plate. First results of both methods suggest that the soil samples release water over the entire tension range measured. In particular, the release of water at very low tension values may suggest the presence of macropores. Despite the generally good agreement between the two methods, the values appear to deviate systematically close to saturation. This is potentially caused by the large relative error of the tension measurement close to saturation. Alternatively, the different size of the samples used for the evaporation experiment (250 ccm) and the steady-state method (100 ccm) might play a role. Because of the limited measurement range of the tensiometers used for the evaporation method, the measured curve must be extrapolated between 850 hPa and 15,000 hPa to allow comparison with the steady-state method. To this end, it was attempted to match the Brooks-Corey, the Van-Genuchten, and a bimodal Van-Genuchten retention function to the data from the evaporation experiments. This involves a simultaneous fit of both water-retention and hydraulic-conductivity function. Only the bimodal Van-Genuchten model was found to be able to produce satisfactory fits to the data. The extrapolated water retention curves, however, do not match the data from the steady-state method. This suggests that alternative soil hydraulic functions are needed to provide an adequate representation of the water retention characteristics of the loamy-sandy soils considered in this investigation.

  11. Insight into the molecular mechanism of water evaporation via the finite temperature string method

    E-print Network

    Musolino, Nicholas

    The process of water's evaporation at its liquid/air interface has proven challenging to study experimentally and, because it constitutes a rare event on molecular time scales, presents a challenge for computer simulations ...

  12. Making parabolic mirrors by electron-beam gun evaporation method with ion-assisted deposition

    Microsoft Academic Search

    Cheng-Chung Jaing; Cheng-Chung Lee; Jin-Cherng Hsu; Chuen-Lin Tien

    2001-01-01

    A spherical surface was modified to form a parabolic surface by the evaporation of Al2O3 films and an ion-assisted deposition process using a designed mask. The stress of the evaporated films was measured by a phase shifting Twyman–Green interferometer. Ion beam bombardment was proven to reduce the stress of Al2O3 films. The optimum ion beam voltage and ion beam current

  13. Physical properties of Sb-doped CdSe thin films by thermal evaporation method

    NASA Astrophysics Data System (ADS)

    Ali, Mazhar; Syed, Waqar A. A.; Zubair, M.; Shah, Nazar A.; Mehmood, Arshad

    2013-11-01

    Cadmium selenide (CdSe) thin films were deposited on the glass substrates by using the resistive thermal evaporation method in the vacuum chamber. The effect of antimony doping on the physical properties of CdSe thin film has been investigated. The structural and surface properties such as lattice parameters, grain size, microstrain and dislocation density of the thin films were characterized by X-ray diffraction (XRD) technique. The compositional properties were studied by the mean of Rutherford backscattering (RBS) and UV-Vis-NIR spectrophotometer used to determine the refractive index, absorption coefficient and optical energy band gap of thin films. The FTIR absorption spectra confirmed the presence of CdSe vibrational mode in the range 400 cm-1 to 700 cm-1. The electrical conductivity of the films was carried out with the help of impedance analyzer, which has been increased up to 1% on Sb doping. The transmission has been reduced up to 18% with the increase in Sb doping and shifted toward lower wavelengths

  14. Paclitaxel loaded niosome nanoparticle formulation prepared via reverse phase evaporation method: an in vitro evaluation.

    PubMed

    Zarei, M; Norouzian, D; Honarvar, B; Mohammadi, M; Shamabadi, H Ebrahimi; Akbarzadeh, A

    2013-03-15

    Niosoms are nanoparticles used in drug delivery systems. Niosomes are prepared by various methods. In this research niosoms were prepared by reverse phase evaporation and the factors affecting the niosomes formation were studied. Percent of paclitaxel pegylated and non-pegylated prepared with Span 60 were 95 and 92, respectively while for those of pegylated and non-pegylated niosomes with Span 20, 94 and 90, respectively. In addition, the average diameters of pegylated and no-pegylated prepared with Span 60 and 20 were determined to be 191, 214, 244 and 284 nm, respectively. The amount of released drug (48 h) from pegylated and non pegylated formulations in the presence of Spans 60 and 20 were 8, 10, 6, 7%, respectively. Cytotoxicities ofpaclitaxel niosom polyethyleneglycol, paclitaxel niosome and free paclitaxel on MCF-7 cell line after 48 hours were studied by MTT assay. The results showed the formulation prepared with Span 60 is more effective than that of Span 20 and the IC50 of the former was decreased twice while IC50 of the later decreased 1.5 times. PMID:24498794

  15. Assessment of Evaporative Cooling Enhancement Methods for Air-Cooled Geothermal Power Plants: Preprint

    SciTech Connect

    Kutscher, C.; Costenaro, D.

    2002-08-01

    Many binary-cycle geothermal power plants are air cooled because insufficient water is available to provide year-round water cooling. The performance of air-cooled geothermal plants is highly dependent on the dry bulb temperature of the air (much more so than fossil fuel plants that operate at higher boiler temperatures), and plant electric output can drop by 50% or more on hot summer days, compared to winter performance. This problem of reduced summer performance is exacerbated by the fact that electricity has a higher value in the summer. This paper describes a spreadsheet model that was developed to assess the cost and performance of four methods for using supplemental evaporative cooling to boost summer performance: (1) pre-cooling with spray nozzles, (2) pre-cooling with Munters media, (3) a hybrid combination of nozzles and Munters media, and (4) direct deluge cooling of the air-cooled condenser tubes. Although all four options show significant benefit, deluge cooling has the potential to be the most economic. However, issues of scaling and corrosion would need to be addressed.

  16. Wave motion of porous particles in a pulsating gas flow in the presence of heat and mass transfer with deepening of the evaporation zone

    NASA Astrophysics Data System (ADS)

    Akulich, P. V.

    2006-09-01

    Based on numerical solution of the dynamics equations of a monodisperse gas suspension with allowance for the interphase forces of aerodynamic drag, virtual masses, and the forces caused by nonstationary effects around particles, the influence of different forms of low-frequency harmonic and anharmonic oscillations of the gas on the motion of porous particles in the presence of heat and mass transfer accompanied by deepening of the evaporation zone has been investigated. The dependences of the solid-phase motion, kinetics of evaporation-zone deepening, and heat and mass transfer on the parameters of gas oscillations have been established. It is shown that on removal of free moisture, oscillations at certain parameters lead to enhancement of interphase heat and mass transfer.

  17. New findings about the complementary relationship-based evaporation estimation methods

    NASA Astrophysics Data System (ADS)

    Szilagyi, Jozsef; Jozsa, Janos

    2008-06-01

    SummaryA novel approach has been found to estimate the equilibrium surface temperature ( Te) of wet environment evaporation ( Ew) on a daily basis. Employing this temperature in the Priestley-Taylor equation as well as in the calculation of the slope of the saturation vapor pressure curve with pan measurements improved the accuracy of long-term mean evaporation ( E) estimation of the Advection-Aridity (AA) model when validated by Morton's approach. Complementarity of the potential evaporation ( Ep) and E terms was considered both on a daily and a monthly basis with the involved terms always calculated daily from 30 yr of hourly meteorological measurements of the 1961-1990 period at 210 SAMSON stations across the contiguous US. The followings were found: (a) only the original Rome wind function of Penman yields a truly symmetric Complementary Relationship between E and Ep which makes the so-obtained Ep estimates true potential evaporation values; (b) the symmetric version of the modified AA model requires no additional parameters to be optimized; (c) for a long-term mean value of evaporation the modified AA model becomes on a par with Morton's approach not only in practical applicability but also in its improved accuracy, especially in arid environments with possible strong convection; (d) the latter two models yielded long-term mean annual evaporation estimates with an R2 of 0.95 for the 210 stations, which is all the more remarkable since they employ very different approaches for their Ep calculations; (e) with identical apparent Ep values the two models yielded practically identical long-term mean annual evaporation rates; (f) with the proper choice of the wind function to estimate apparent Ep the long-term mean annual E estimates of the modified AA model are still very close ( R2 = 0.93) to those of the Morton approach.

  18. Kinetic multi-layer model of gas-particle interactions in aerosols and clouds (KM-GAP): linking condensation, evaporation and chemical reactions of organics, oxidants and water

    NASA Astrophysics Data System (ADS)

    Shiraiwa, M.; Pfrang, C.; Koop, T.; Pöschl, U.

    2012-03-01

    We present a novel kinetic multi-layer model for gas-particle interactions in aerosols and clouds (KM-GAP) that treats explicitly all steps of mass transport and chemical reaction of semi-volatile species partitioning between gas phase, particle surface and particle bulk. KM-GAP is based on the PRA model framework (Pöschl-Rudich-Ammann, 2007), and it includes gas phase diffusion, reversible adsorption, surface reactions, bulk diffusion and reaction, as well as condensation, evaporation and heat transfer. The size change of atmospheric particles and the temporal evolution and spatial profile of the concentration of individual chemical species can be modeled along with gas uptake and accommodation coefficients. Depending on the complexity of the investigated system and the computational constraints, unlimited numbers of semi-volatile species, chemical reactions, and physical processes can be treated, and the model shall help to bridge gaps in the understanding and quantification of multiphase chemistry and microphysics in atmospheric aerosols and clouds. In this study we demonstrate how KM-GAP can be used to analyze, interpret and design experimental investigations of changes in particle size and chemical composition in response to condensation, evaporation, and chemical reaction. For the condensational growth of water droplets, our kinetic model results provide a direct link between laboratory observations and molecular dynamic simulations, confirming that the accommodation coefficient of water at ~270 K is close to unity (Winkler et al., 2006). Literature data on the evaporation of dioctyl phthalate as a function of particle size and time can be reproduced, and the model results suggest that changes in the experimental conditions like aerosol particle concentration and chamber geometry may influence the evaporation kinetics and can be optimized for efficient probing of specific physical effects and parameters. With regard to oxidative aging of organic aerosol particles, we illustrate how the formation and evaporation of volatile reaction products like nonanal can cause a decrease in the size of oleic acid particles exposed to ozone.

  19. Gas sensitive materials for gas detection and methods of making

    DOEpatents

    Trakhtenberg, Leonid Israilevich; Gerasimov, Genrikh Nikolaevich; Gromov, Vladimir Fedorovich; Rozenberg, Valeriya Isaakovna

    2014-07-15

    A gas sensitive material comprising SnO.sub.2 nanocrystals doped with In.sub.2O.sub.3 and an oxide of a platinum group metal, and a method of making the same. The platinum group metal is preferably Pd, but also may include Pt, Ru, Ir, and combinations thereof. The SnO.sub.2 nanocrystals have a specific surface of 7 or greater, preferably about 20 m2/g, and a mean particle size of between about 10 nm and about 100 nm, preferably about 40 nm. A gas detection device made from the gas sensitive material deposited on a substrate, the gas sensitive material configured as a part of a current measuring circuit in communication with a heat source.

  20. Evanescent-wave trapping and evaporative cooling of an atomic gas near two-dimensionality

    E-print Network

    M. Hammes; D. Rychtarik; B. Engeser; H. -C. Nägerl; R. Grimm

    2002-08-16

    A dense gas of cesium atoms at the crossover to two-dimensionality is prepared in a highly anisotropic surface trap that is realized with two evanescent light waves. Temperatures as low as 100nK are reached with 20.000 atoms at a phase-space density close to 0.1. The lowest quantum state in the tightly confined direction is populated by more than 60%. The system offers intriguing prospects for future experiments on degenerate quantum gases in two dimensions.

  1. Evaporation of liquefied natural gas in conditions of compact storage containers heating

    NASA Astrophysics Data System (ADS)

    Telgozhayeva, D. S.

    2014-08-01

    Identical by its power, but located in different parts of the external surface of the tank, the heating sources are different intensity heat transfer modes is heating up, respectively, times of vapour pressure rise to critical values. Developed mathematical model and method of calculation can be used in the analysis of conditions of storage tanks for liquefied gases.

  2. A sensor-based energy balance method for the distributed estimation of evaporation over the North American Great Lakes

    NASA Astrophysics Data System (ADS)

    Fries, K. J.; Kerkez, B.; Gronewold, A.; Lenters, J. D.

    2014-12-01

    We introduce a novel energy balance method to estimate evaporation across large lakes using real-time data from moored buoys and mobile, satellite-tracked drifters. Our work is motivated by the need to improve our understanding of the water balance of the Laurentian Great Lakes basin, a complex hydrologic system that comprises 90% of the United States' and 20% of the world's fresh surface water. Recently, the lakes experienced record-setting water level drops despite above-average precipitation, and given that lake surface area comprises nearly one third of the entire basin, evaporation is suspected to be the primary driver behind the decrease in water levels. There has historically been a need to measure evaporation over the Great Lakes, and recent hydrological phenomena (including not only record low levels, but also extreme changes in ice cover and surface water temperatures) underscore the urgency of addressing that need. Our method tracks the energy fluxes of the lake system - namely net radiation, heat storage and advection, and Bowen ratio. By measuring each of these energy budget terms and combining the results with mass-transfer based estimates, we can calculate real-time evaporation rates on sub-hourly timescales. To mitigate the cost prohibitive nature of large-scale, distributed energy flux measurements, we present a novel approach in which we leverage existing investments in seasonal buoys (which, while providing intensive, high quality data, are costly and sparsely distributed across the surface of the Great Lakes) and then integrate data from less costly satellite-tracked drifter data. The result is an unprecedented, hierarchical sensor and modeling architecture that can be used to derive estimates of evaporation in real-time through cloud-based computing. We discuss recent deployments of sensor-equipped buoys and drifters, which are beginning to provide us with some of the first in situ measurements of overlake evaporation from Earth's largest lake system, opening up the potential for improved and integrated monitoring and modeling of the Great Lakes water budget.

  3. RPC gas recovery by open loop method

    NASA Astrophysics Data System (ADS)

    Joshi, Avinash; Kalmani, S. D.; Mondal, N. K.; Satyanarayana, B.

    2009-05-01

    RPC detectors require to be flushed with small but continuous flow of gas mixture. Dealing with large number of detectors, gas consumption to very large volumes. Gas flow is a running expense and constituent gases are too expensive to be treated as consumables. Exhaust gas mixture from detectors is a potential environmental hazard if discharged directly into the atmosphere. Storage of gases on a large scale also leads to inventory- and safety-related problems. A solution to these problems is the recovery and reuse of exhaust gas mixture from RPC detectors. Close loop method employs recirculation of exhausted gas mixture after purification, analysis and addition of top-up quantities. In open loop method, under consideration here, individual component gases are separated from gas mixture and reused as source. During open loop process, gases liquefiable at low pressures are separated from ones liquefiable at high pressure. The gas phase components within each group are successively separated by either fractional condensation or gravity separation. Gas mixture coming from RPC exhaust is first desiccated by passage through molecular sieve adsorbent type (3A+4A). Subsequent scrubbing over basic activated alumina removes toxic and acidic contaminants such as S 2F 10 produced during corona (arcing) discharge. In the first stage of separation isobutane and freon are concentrated by diffusion and liquefied by fractional condensation by cooling upto -30 °C. Liquefied gases are returned to source tanks. In the second stage of separation, argon and sulphur hexafluoride, the residual gases, are concentrated by settling due to density difference. SF 6 is stored for recovery by condensation at high pressure while argon is further purified by thermal cracking of crossover impurities at 1000 °C followed by wet scrubbing.

  4. Acetone and ethanol solid-state gas sensors based on TiO 2 nanoparticles thin film deposited by matrix assisted pulsed laser evaporation

    Microsoft Academic Search

    R. Rella; J. Spadavecchia; M. G. Manera; S. Capone; A. Taurino; M. Martino; A. P. Caricato; T. Tunno

    2007-01-01

    Matrix assisted pulsed laser evaporation (MAPLE) is a new promising laser-based technique thought for polymer or biomaterial thin films deposition. In this work, the MAPLE technique has been used for the deposition of titania (TiO2) nanoparticle thin films to be used for gas sensor applications. For this purpose, an aqueous solution of TiO2 nanoparticles, synthesized by a novel chemical route,

  5. Method for improved gas-solids separation

    DOEpatents

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

    1990-11-13

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

  6. New Correlation Methods of Evaporation Heat Transfer in Horizontal Microfine Tubes

    NASA Astrophysics Data System (ADS)

    Makishi, Osamu; Honda, Hiroshi

    A stratified flow model and an annular flow model of evaporation heat transfer in horizontal microfin tubes have been proposed. In the stratified flow model, the contributions of thin film evaporation and nucleate boiling in the groove above a stratified liquid were predicted by a previously reported numerical analysis and a newly developed correlation, respectively. The contributions of nucleate boiling and forced convection in the stratified liquid region were predicted by the new correlation and the Carnavos equation, respectively. In the annular flow model, the contributions of nucleate boiling and forced convection were predicted by the new correlation and the Carnavos equation in which the equivalent Reynolds number was introduced, respectively. A flow pattern transition criterion proposed by Kattan et al. was incorporated to predict the circumferential average heat transfer coefficient in the intermediate region by use of the two models. The predictions of the heat transfer coefficient compared well with available experimental data for ten tubes and four refrigerants.

  7. Insight into the molecular mechanism of water evaporation via the finite temperature string method

    PubMed Central

    Musolino, Nicholas; Trout, Bernhardt L.

    2013-01-01

    The process of water's evaporation at its liquid/air interface has proven challenging to study experimentally and, because it constitutes a rare event on molecular time scales, presents a challenge for computer simulations as well. In this work, we simulated water's evaporation using the classical extended simple point charge model water model, and identified a minimum free energy path for this process in terms of 10 descriptive order parameters. The measured free energy change was 7.4 kcal/mol at 298 K, in reasonable agreement with the experimental value of 6.3 kcal/mol, and the mean first-passage time was 1375 ns for a single molecule, corresponding to an evaporation coefficient of 0.25. In the observed minimum free energy process, the water molecule diffuses to the surface, and tends to rotate so that its dipole and one O–H bond are oriented outward as it crosses the Gibbs dividing surface. As the water molecule moves further outward through the interfacial region, its local density is higher than the time-averaged density, indicating a local solvation shell that protrudes from the interface. The water molecule loses donor and acceptor hydrogen bonds, and then, with its dipole nearly normal to the interface, stops donating its remaining hydrogen bond. At that point, when the final, accepted hydrogen bond is broken, the water molecule is free. We also analyzed which order parameters are most important in the process and in reactive trajectories, and found that the relative orientation of water molecules near the evaporating molecule, and the number of accepted hydrogen bonds, were important variables in reactive trajectories and in kinetic descriptions of the process. PMID:23574252

  8. Effects of heating method and conditions on the evaporation rate and quality attributes of black mulberry ( Morus nigra ) juice concentrate

    Microsoft Academic Search

    Mahboubeh Fazaeli; Ghazale Hojjatpanah; Zahra Emam-Djomeh

    Black mulberry juice was concentrated by different heating methods, including conventional heating and microwave heating,\\u000a at different operational pressures (7.3, 38.5 and 100 kPa). The effects of each method on evaporation rate, quality attributes\\u000a of concentrated juice were investigated. The final juice concentration of 42° Brix was achieved in 140, 120, and 95 min at\\u000a 100, 38.5, and 7.3 kPa respectively by using

  9. Method for designing gas tag compositions

    DOEpatents

    Gross, K.C.

    1995-04-11

    For use in the manufacture of gas tags such as employed in a nuclear reactor gas tagging failure detection system, a method for designing gas tagging compositions utilizes an analytical approach wherein the final composition of a first canister of tag gas as measured by a mass spectrometer is designated as node No. 1. Lattice locations of tag nodes in multi-dimensional space are then used in calculating the compositions of a node No. 2 and each subsequent node so as to maximize the distance of each node from any combination of tag components which might be indistinguishable from another tag composition in a reactor fuel assembly. Alternatively, the measured compositions of tag gas numbers 1 and 2 may be used to fix the locations of nodes 1 and 2, with the locations of nodes 3-N then calculated for optimum tag gas composition. A single sphere defining the lattice locations of the tag nodes may be used to define approximately 20 tag nodes, while concentric spheres can extend the number of tag nodes to several hundred. 5 figures.

  10. Spectroscopic methods in gas hydrate research.

    PubMed

    Rauh, Florian; Mizaikoff, Boris

    2012-01-01

    Gas hydrates are crystalline structures comprising a guest molecule surrounded by a water cage, and are particularly relevant due to their natural occurrence in the deep sea and in permafrost areas. Low molecular weight molecules such as methane and carbon dioxide can be sequestered into that cage at suitable temperatures and pressures, facilitating the transition to the solid phase. While the composition and structure of gas hydrates appear to be well understood, their formation and dissociation mechanisms, along with the dynamics and kinetics associated with those processes, remain ambiguous. In order to take advantage of gas hydrates as an energy resource (e.g., methane hydrate), as a sequestration matrix in (for example) CO(2) storage, or for chemical energy conservation/storage, a more detailed molecular level understanding of their formation and dissociation processes, as well as the chemical, physical, and biological parameters that affect these processes, is required. Spectroscopic techniques appear to be most suitable for analyzing the structures of gas hydrates (sometimes in situ), thus providing access to such information across the electromagnetic spectrum. A variety of spectroscopic methods are currently used in gas hydrate research to determine the composition, structure, cage occupancy, guest molecule position, and binding/formation/dissociation mechanisms of the hydrate. To date, the most commonly applied techniques are Raman spectroscopy and solid-state nuclear magnetic resonance (NMR) spectroscopy. Diffraction methods such as neutron and X-ray diffraction are used to determine gas hydrate structures, and to study lattice expansions. Furthermore, UV-vis spectroscopic techniques and scanning electron microscopy (SEM) have assisted in structural studies of gas hydrates. Most recently, waveguide-coupled mid-infrared spectroscopy in the 3-20 ?m spectral range has demonstrated its value for in situ studies on the formation and dissociation of gas hydrates. This comprehensive review summarizes the importance of spectroscopic analytical techniques to our understanding of the structure and dynamics of gas hydrate systems, and highlights selected examples that illustrate the utility of these individual methods. PMID:22094590

  11. Standard test method for determination of uranium or plutonium isotopic composition or concentration by the total evaporation method using a thermal ionization mass spectrometer

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This method describes the determination of the isotopic composition and/or the concentration of uranium and plutonium as nitrate solutions by the thermal ionization mass spectrometric (TIMS) total evaporation method. Purified uranium or plutonium nitrate solutions are loaded onto a degassed metal filament and placed in the mass spectrometer. Under computer control, ion currents are generated by heating of the filament(s). The ion beams are continually measured until the sample is exhausted. The measured ion currents are integrated over the course of the run, and normalized to a reference isotope ion current to yield isotopic ratios. 1.2 In principle, the total evaporation method should yield isotopic ratios that do not require mass bias correction. In practice, some samples may require this bias correction. When compared to the conventional TIMS method, the total evaporation method is approximately two times faster, improves precision from two to four fold, and utilizes smaller sample sizes. 1.3 The tot...

  12. Utility of Penman-Monteith, Priestley-Taylor, reference evapotranspiration, and pan evaporation methods to estimate pasture evapotranspiration

    USGS Publications Warehouse

    Sumner, D.M.; Jacobs, J.M.

    2005-01-01

    Actual evapotranspiration (ETa) was measured at 30-min resolution over a 19-month period (September 28, 2000-April 23, 2002) from a nonirrigated pasture site in Florida, USA, using eddy correlation methods. The relative magnitude of measured ETa (about 66% of long-term annual precipitation at the study site) indicates the importance of accurate ET a estimates for water resources planning. The time and cost associated with direct measurements of ETa and the rarity of historical measurements of ETa make the use of methods relying on more easily obtainable data desirable. Several such methods (Penman-Monteith (PM), modified Priestley-Taylor (PT), reference evapotranspiration (ET 0), and pan evaporation (Ep)) were related to measured ETa using regression methods to estimate PM bulk surface conductance, PT ??, ET0 vegetation coefficient, and Ep pan coefficient. The PT method, where the PT ?? is a function of green-leaf area index (LAI) and solar radiation, provided the best relation with ET a (standard error (SE) for daily ETa of 0.11 mm). The PM method, in which the bulk surface conductance was a function of net radiation and vapor-pressure deficit, was slightly less effective (SE=0.15 mm) than the PT method. Vegetation coefficients for the ET0 method (SE=0.29 mm) were found to be a simple function of LAI. Pan coefficients for the Ep method (SE=0.40 mm) were found to be a function of LAI and Ep. Historical or future meteorological, LAI, and pan evaporation data from the study site could be used, along with the relations developed within this study, to provide estimates of ETa in the absence of direct measurements of ETa. Additionally, relations among PM, PT, and ET0 methods and ETa can provide estimates of ETa in other, environmentally similar, pasture settings for which meteorological and LAI data can be obtained or estimated. ?? 2004 Elsevier B.V. All rights reserved.

  13. Thickness and oxygen partial pressure dependence on optical band gap of indium oxide by reactive evaporation method

    NASA Astrophysics Data System (ADS)

    Muhammed Ali, A. V.; Kekuda, Dhananjaya

    2015-02-01

    Indium oxide film is deposited by reactive evaporation of indium in the presence of oxygen gas onto an unheated glass substrate. It was found that thickness of the film and partial oxygen pressure during the deposition affects the optical properties of the indium oxide thin film. We studied the optical band gap for different thickness and partial pressure keeping a constant annealing temperature. It was found that the band gap varies from 3.5 to 3.8eV, as thickness of the film increased. The band gap energy had also shows the similar trend and it was also studied as a function of annealing temperature. A systematic investigation of the optical band gap as a function of thickness and oxygen partial pressure at different annealing temperature was carried out.

  14. Conversion method for gas streams containing hydrocarbons

    SciTech Connect

    Mallinson, Richard G. (Norman, OK); Lobban, Lance (Norman, OK); Liu, Chang-jun (Tianjin, CN)

    2000-01-01

    An apparatus and a method of using the apparatus are provided for converting a gas stream containing hydrocarbons to a reaction product containing effluent molecules having at least one carbon atom, having at least one interior surface and at least one exterior surface, a first electrode and a second electrode with the first and second electrodes being selectively movable in relation to each other and positioned within the housing so as to be spatially disposed a predetermined distance from each other, a plasma discharge generator between the first and second electrodes, gas stream introducer and a collector for collecting the reaction product effluent produced by the reaction of the gas stream containing hydrocarbons with the plasma discharge between the first and second electrodes.

  15. (bulb) , (1) Gas(1) Gas(1) Gas(1) Gas----saturation methodsaturation methodsaturation methodsaturation method

    E-print Network

    Hong, Deog Ki

    -tube . isoteniscope . (3) Boiling Point Method (Dynamic Method)(3) Boiling Point Method (Dynamic Method)(3) Boiling Point Method (Dynamic Method)(3) Boiling Point Method (Dynamic Method) . ballast bulb . manometer . . Isoteniscope Boling Point Method . #12;2. (1) Boiling-Point

  16. Method for operating a flue gas desulfurization

    SciTech Connect

    Karger, R.; Weinzierl, K.

    1983-02-01

    A method of operating a flue gas desulfurization with a steam power plant heated with fossil fuels. The sulfur dioxide contained in the flue gas is removed in a wash tower by means of an excess of milk of lime or limestone, and the resulting sulfite is oxidized with air at a low ph-value into calcium sulfate. The non-converted milk of lime or limestone is neutralized at least partially by an addition of acid waste waters from a complete desalination plant for the supply water, and/or by an addition of acid condensate from the flue or chimney of the steam power plant. An installation for carrying out the method of the present invention includes a wash tower having flue gas flowing therethrough, an oxidation tower having air flowing therethrough, milk of lime or limestone supply into the wash tower, and a delivery device for the wash liquid in the wash tower and in the oxidation tower, with the device having a pump for liquid drawn off from the sump of the wash tower. The sump of the wash tower is connected with a supply line for acid waste water from a complete desalination plant, and/or with a supply line for acid condensate from the chimney or flue of the steam power plant.

  17. Children's understanding of changes of state involving the gas state, Part 2: Evaporation and condensation below boiling point

    Microsoft Academic Search

    Philip Johnson

    1998-01-01

    Deriving from a three?year longitudinal study which explored the development of children's concept of a substance (ages 11 to 14), part 2 of this paper (see Johnson 1998b) reports findings in relation to evaporation at room temperature and condensation of atmospheric water vapour. Part one had reported findings in relation to boiling water and the development of pupils’ understanding of

  18. Method and apparatus for producing synthesis gas

    DOEpatents

    Hemmings, John William (Katy, TX); Bonnell, Leo (Houston, TX); Robinson, Earl T. (Mentor, OH)

    2010-03-03

    A method and apparatus for reacting a hydrocarbon containing feed stream by steam methane reforming reactions to form a synthesis gas. The hydrocarbon containing feed is reacted within a reactor having stages in which the final stage from which a synthesis gas is discharged incorporates expensive high temperature materials such as oxide dispersed strengthened metals while upstream stages operate at a lower temperature allowing the use of more conventional high temperature alloys. Each of the reactor stages incorporate reactor elements having one or more separation zones to separate oxygen from an oxygen containing feed to support combustion of a fuel within adjacent combustion zones, thereby to generate heat to support the endothermic steam methane reforming reactions.

  19. Evaporation of germanium nitride

    Microsoft Academic Search

    É. A. Ryklis; A. S. Bolgar; M. D. Lyutaya; V. V. Fesenko

    1968-01-01

    1.A study was made, using Knudsen's effusion method, of the evaporation of germanium nitride over the temperature range 923–963°K. It is shown that, on evaporation, this compound dissociates into solid germanium and nitrogen.2.The vapor pressure above germanium nitride depends on test duration and on the surface area of the effusion orifice.3.The equilibrium values of vapor pressure above Ge3N4 and the

  20. Method for controlling gas metal arc welding

    DOEpatents

    Smartt, Herschel B. (Idaho Falls, ID); Einerson, Carolyn J. (Idaho Falls, ID); Watkins, Arthur D. (Idaho Falls, ID)

    1989-01-01

    The heat input and mass input in a Gas Metal Arc welding process are controlled by a method that comprises calculating appropriate values for weld speed, filler wire feed rate and an expected value for the welding current by algorithmic function means, applying such values for weld speed and filler wire feed rate to the welding process, measuring the welding current, comparing the measured current to the calculated current, using said comparison to calculate corrections for the weld speed and filler wire feed rate, and applying corrections.

  1. Method for controlling gas metal arc welding

    DOEpatents

    Smartt, H.B.; Einerson, C.J.; Watkins, A.D.

    1987-08-10

    The heat input and mass input in a Gas Metal Arc welding process are controlled by a method that comprises calculating appropriate values for weld speed, filler wire feed rate and an expected value for the welding current by algorithmic function means, applying such values for weld speed and filler wire feed rate to the welding process, measuring the welding current, comparing the measured current to the calculated current, using said comparison to calculate corrections for the weld speed and filler wire feed rate, and applying corrections. 3 figs., 1 tab.

  2. Utility of PenmanMonteith, PriestleyTaylor, reference evapotranspiration, and pan evaporation methods to estimate

    E-print Network

    . Several such methods (Penman­Monteith (PM), modified Priestley­Taylor (PT), reference evapotranspiration bulk surface conductance, PT a, ET0 vegetation coefficient, and Ep pan coefficient. The PT method relation with ETa (standard error (SE) for daily ETa of 0.11 mm). The PM method, in which the bulk surface

  3. Method of testing a cold gas for the presence of a hazardous gas

    SciTech Connect

    Kutta, H.W.; Morrison, O.C.

    1988-12-20

    This patent describes a method for testing a gas at a temperature below about -10 degrees F for the presence of a hazardous gas. The method consists of: (a) passing a quantity of the gas through a tubing positioned in a garment and near the inner surface of the garment so that body heat of a wearer of the garment is transferred to the gas flowing through the tubing to heat the quantity of gas with the body heat of the wearer of the garment; and (b) analyzing a portion of the heated quantity of gas for the presence of the hazardous gas.

  4. Kinetic approach to the evaporation and condensation problem

    NASA Technical Reports Server (NTRS)

    Murakami, M.; Oshima, K.

    1974-01-01

    In the paper, the Boltzmann equation governing the evaporation and condensation phenomena is solved by the Monte Carlo method. Based on the kinetic theory of gas the role of the non-equilibrium Knudsen layer and the growth of the hydrodynamic region outside the layer as time proceeds are simulated. Results show two possible types of transient developments in the vapor phase. The effects of the molecular absorption coefficient of the phase surface are examined. Except in the case of very strong evaporation the kinematic effects of binary collisions among vapor molecules on the mass flux rate are not serious. The limiting case of the quasi-steady evaporation and the maximal value of the evaporation rate are obtained.

  5. Method for mapping a natural gas leak

    DOEpatents

    Reichardt, Thomas A. (Livermore, CA); Luong, Amy Khai (Dublin, CA); Kulp, Thomas J. (Livermore, CA); Devdas, Sanjay (Albany, CA)

    2009-02-03

    A system is described that is suitable for use in determining the location of leaks of gases having a background concentration. The system is a point-wise backscatter absorption gas measurement system that measures absorption and distance to each point of an image. The absorption measurement provides an indication of the total amount of a gas of interest, and the distance provides an estimate of the background concentration of gas. The distance is measured from the time-of-flight of laser pulse that is generated along with the absorption measurement light. The measurements are formatted into an image of the presence of gas in excess of the background. Alternatively, an image of the scene is superimposed on the image of the gas to aid in locating leaks. By further modeling excess gas as a plume having a known concentration profile, the present system provides an estimate of the maximum concentration of the gas of interest.

  6. Carrier Gas Dependent Evaporation Energy of GaN Estimated from Spiral Growth Rates in Selective-Area Metalorganic Vapor Phase Epitaxy

    NASA Astrophysics Data System (ADS)

    Akasaka, Tetsuya; Kobayashi, Yasuyuki; Kasu, Makoto; Yamamoto, Hideki

    2013-10-01

    GaN was grown in spiral growth mode by metalorganic vapor phase epitaxy in selective areas having screw-type dislocations. Relationships between the growth rate and supersaturation provide a novel way to estimate the evaporation energy of GaN, which turns out to be carrier gas dependent: 4.3±0.9 eV for N2 and 2.1±0.4 eV for H2. The latter is significantly smaller, probably due to enhanced etching by H2. Suppression of excessive nucleation by etching in H2 may be responsible for the formation of step-free GaN surfaces at low temperatures in selective areas free from screw-type dislocations.

  7. Video-taped sample evaporation in hot chambers simulating gas chromatography split and splitless injectors. II. Injection with band formation.

    PubMed

    Grob, K; Biedermann, M

    2000-11-01

    The processes in devices imitating a vaporising injector were video-taped using perylene as a fluorescent marker for non-evaporated sample. Processes are summarised which are observed after the sample liquid passed through a cool needle and left as a band of liquid moving at high velocity (as typical for injection by fast autosamplers). This liquid is shot past the column entrance unless stopped either by a packing, e.g., wool or by suitable obstacles. Packings of low thermal mass are locally cooled to the solvent boiling point and suck in the liquid. Stopping the liquid by obstacles is more difficult because solvent vapours prevent contact of the liquid with the hot surfaces, and was reliably achieved only by the laminar liner. For the same reason, transfer onto the liner wall only occurs for higher boiling liquids. PMID:11128209

  8. A new method using evaporation for high-resolution measurements of soil thermal conductivity at changing water contents

    NASA Astrophysics Data System (ADS)

    Markert, A.; Trinks, S.; Facklam, M.; Wessolek, G.

    2012-04-01

    The thermal conductivity of soils is a key parameter to know if their use as heat source or sink is planned. It is required to calculate the efficiency of ground-source heat pump systems in combination with soil heat exchangers. Apart from geothermal energy, soil thermal conductivity is essential to estimate the ampacity for buried power cables. The effective thermal conductivity of saturated and unsaturated soils, as a function of water transport, water vapour transport and heat conduction, mainly depends on the soil water content, its bulk density and texture. The major objectives of this study are (i) to describe the thermal conductivity of soil samples with a non-steady state measurement at changing water contents and for different bulk densities. Based on that it is (ii) tested if available soil thermal conductivity models are able to describe the measured data for the whole range of water contents. The new method allows a continuous measurement of thermal conductivity for soil from full water saturation to air-dryness. Thermal conductivity is measured with a thermal needle probe in predefined time intervals while the change of water content is controlled by evaporation. To relate the measured thermal conductivity to the current volumetric water content, the decrease in weight of the sample, due to evaporation, is logged with a lab scale. Soil texture of the 11 soil substrates tested in this study range between coarse sand and silty clay. To evaluate the impact of the bulk density on heat transport processes, thermal conductivity at 20°C was measured at 1.5g/cm3; 1.7g/cm3 and 1.9g/cm3 for each soil substrate. The results correspond well to literature values used to describe heat transport in soils. Due to the high-resolution and non-destructive measurements, the specific effects of the soil texture and bulk density on thermal conductivity could be proved. Decreasing water contents resulted in a non-linear decline of the thermal conductivity for all samples. Especially for coarse textured soils a rapid decrease of the thermal conductivity was observed, when the volumetric water content drops under a critical level. Higher bulk densities increased the heat transport parameters for soil samples with the same texture. This effect becomes significant at high water saturations. The method used in this study allows easy to use non-steady state measurements of the soil thermal conductivity with a high data resolution and for continuously decreasing water contents. In further studies these measured data will be used to enhance existing pedotransfer functions and models and improve the prediction of soil thermal properties for application-oriented requirements.

  9. Method and apparatus for manufacturing gas tags

    DOEpatents

    Gross, Kenny C. (Bolingbrook, IL); Laug, Matthew T. (Idaho Falls, ID)

    1996-01-01

    For use in the manufacture of gas tags employed in a gas tagging failure detection system for a nuclear reactor, a plurality of commercial feed gases each having a respective noble gas isotopic composition are blended under computer control to provide various tag gas mixtures having selected isotopic ratios which are optimized for specified defined conditions such as cost. Using a new approach employing a discrete variable structure rather than the known continuous-variable optimization problem, the computer controlled gas tag manufacturing process employs an analytical formalism from condensed matter physics known as stochastic relaxation, which is a special case of simulated annealing, for input feed gas selection. For a tag blending process involving M tag isotopes with N distinct feed gas mixtures commercially available from an enriched gas supplier, the manufacturing process calculates the cost difference between multiple combinations and specifies gas mixtures which approach the optimum defined conditions. The manufacturing process is then used to control tag blending apparatus incorporating tag gas canisters connected by stainless-steel tubing with computer controlled valves, with the canisters automatically filled with metered quantities of the required feed gases.

  10. Method and apparatus for manufacturing gas tags

    DOEpatents

    Gross, K.C.; Laug, M.T.

    1996-12-17

    For use in the manufacture of gas tags employed in a gas tagging failure detection system for a nuclear reactor, a plurality of commercial feed gases each having a respective noble gas isotopic composition are blended under computer control to provide various tag gas mixtures having selected isotopic ratios which are optimized for specified defined conditions such as cost. Using a new approach employing a discrete variable structure rather than the known continuous-variable optimization problem, the computer controlled gas tag manufacturing process employs an analytical formalism from condensed matter physics known as stochastic relaxation, which is a special case of simulated annealing, for input feed gas selection. For a tag blending process involving M tag isotopes with N distinct feed gas mixtures commercially available from an enriched gas supplier, the manufacturing process calculates the cost difference between multiple combinations and specifies gas mixtures which approach the optimum defined conditions. The manufacturing process is then used to control tag blending apparatus incorporating tag gas canisters connected by stainless-steel tubing with computer controlled valves, with the canisters automatically filled with metered quantities of the required feed gases. 4 figs.

  11. Method for processing coke oven gas

    SciTech Connect

    Flockenhaus, C.; Meckel, J.F.; Wagener, D.

    1980-11-25

    Coke oven gas is subjected, immediately after the discharge thereof from coke ovens, and without any preliminary cooling operation or any purification operation other than desulfurization, to a catalytic cracking operation to form a hot cracked gas which is rich in hydrogen and carbon monoxide. The catalytic cracking reaction is carried out in the presence of a hydrogen-containing and/or CO2-containing gas, with a steam reforming catalyst.

  12. Prevention against Oxidation of Mn Evaporant during Reactive Evaporation Process

    Microsoft Academic Search

    Masaaki Isai; Hiroshi Fujiyasu

    2001-01-01

    Manganese oxide films for lithium secondary batteries were prepared using a reactive evaporation method. The Mn metal in the crucible suffers severe oxidation during the reactive evaporation process, during which its deposition rate deteriorates with increasing deposition run. So it is difficult to maintain the stoichiometry of films from run to run. To prevent deteriorations, a quartz ampoule has been

  13. Noble gas-halogen transfer laser method and means

    Microsoft Academic Search

    R. M. Hill; D. L. Huestis; D. C. Lorents; M. V. Mccusker

    1981-01-01

    A halogen transfer laser method and means are disclosed employing a dilute mixture of molecular halogen vapor in high pressure noble gas. Noble gas atoms and molecules are excited by use of electrons to high energy metastable and\\/or excimer states. Collisional and\\/or radiative transfer of electronic excitation from the excited noble gas atoms and molecules to the lasing halogen molecules

  14. Study of a Novel Method for the Thermolysis of Solutes in Aqueous Solution Using a Low Temperature Bubble Column Evaporator.

    PubMed

    Shahid, Muhammad; Xue, Xinkai; Fan, Chao; Ninham, Barry W; Pashley, Richard M

    2015-06-25

    An enhanced thermal decomposition of chemical compounds in aqueous solution has been achieved at reduced solution temperatures. The technique exploits hitherto unrecognized properties of a bubble column evaporator (BCE). It offers better heat transfer efficiency than conventional heat transfer equipment. This is obtained via a continuous flow of hot, dry air bubbles of optimal (1-3 mm) size. Optimal bubble size is maintained by using the bubble coalescence inhibition property of some salts. This novel method is illustrated by a study of thermal decomposition of ammonium bicarbonate (NH4HCO3) and potassium persulfate (K2S2O8) in aqueous solutions. The decomposition occurs at significantly lower temperatures than those needed in bulk solution. The process appears to work via the continuous production of hot (e.g., 150 °C) dry air bubbles, which do not heat the solution significantly but produce a transient hot surface layer around each rising bubble. This causes the thermal decomposition of the solute. The decomposition occurs due to the effective collision of the solute with the surface of the hot bubbles. The new process could, for example, be applied to the regeneration of the ammonium bicarbonate draw solution used in forward osmosis. PMID:26067442

  15. Efficiency of methods for Karl Fischer determination of water in oils based on oven evaporation and azeotropic distillation.

    PubMed

    Larsson, William; Jalbert, Jocelyn; Gilbert, Roland; Cedergren, Anders

    2003-03-15

    The efficiency of azeotropic distillation and oven evaporation techniques for trace determination of water in oils has recently been questioned by the National Institute of Standards and Technology (NIST), on the basis of measurements of the residual water found after the extraction step. The results were obtained by volumetric Karl Fischer (KF) titration in a medium containing a large excess of chloroform (> or = 65%), a proposed prerequisite to ensure complete release of water from the oil matrix. In this work, the extent of this residual water was studied by means of a direct zero-current potentiometric technique using a KF medium containing more than 80% chloroform, which is well above the concentration recommended by NIST. A procedure is described that makes it possible to correct the results for dilution errors as well as for chemical interference effects caused by the oil matrix. The corrected values were found to be in the range of 0.6-1.5 ppm, which should be compared with the 12-34 ppm (uncorrected values) reported by NIST for the same oils. From this, it is concluded that the volumetric KF method used by NIST gives results that are much too high. PMID:12659179

  16. Comparative Study of As-Deposited ZnO Thin Films by Thermal Evaporation, Pulsed Laser Deposition and RF Sputtering Methods for Electronic and Optoelectronic Applications

    NASA Astrophysics Data System (ADS)

    Vyas, Sumit; Giri, Pushpa; Singh, Shaivalini; Chakrabarti, P.

    2015-06-01

    Zinc oxide (ZnO) thin films have been deposited on Si substrate and glass substrate using thermal evaporation, pulsed laser deposition (PLD) and radio-frequency (RF) sputtering methods. The structural, surface morphological, optical and electrical properties of ZnO thin films deposited by these three methods were investigated and compared systematically using x-ray diffractometer, atomic force microscopy, ellipsometric and current-voltage (I-V) measurement. The ZnO films deposited by RF sputtering method were highly oriented along the (002) plane. The ZnO films grown by thermal evaporation and PLD methods exhibited a polycrystalline nature. The surface roughness was found to be the least and the transparency in the visible region was the highest for the films grown by the RF sputtering method as compared to the films grown by the other two methods. The I-V characteristics reveal that the Pd:Au/ZnO (RF-sputtered) Schottky contact exhibited a better value of ideality factor, series resistance and barrier height as compared to the values obtained for Pd:Au/ZnO (thermally evaporated and pulse laser-deposited) Schottky contacts. The optical bandgap was found to be almost the same for the films grown by all three methods and was estimated to be around 3.2 eV.

  17. Effect of gas flow swirling on coating deposition by the cold gas-dynamic spray method

    NASA Astrophysics Data System (ADS)

    Kiselev, S. P.; Kiselev, V. P.; Zaikovskii, V. N.

    2012-03-01

    The effect of gas flow swirling on the process of coating deposition onto a target by the cold gas-dynamic spray method is studied experimentally and numerically. Flow swirling is found to change the gas flow field and to reduce the gas flow rate under typical conditions of cold gas-dynamic spray. In a non-swirled flow, the shape of the deposited spot is similar to a sharp cone. In contrast, the deposited spot in a swirled flow is shaped as a crater without particles at the center of this crater. It is found that this effect is caused by centrifugal forces acting on particles in a swirled gas flow.

  18. Method and apparatus for pressurizing a liquefied gas

    DOEpatents

    Bingham, Dennis N.

    2005-07-26

    Apparatus providing at least one thermoelectric device for pressurizing a liquefied gas container and methods employing same are disclosed. A thermoelectric device including a heating surface and a cooling surface is used for pressurizing a container by vaporizing liquefied gas within the container by transferring heat energy from a portion of the liquefied gas in contact with the cooling surface to another portion of the liquefied gas in contact with the heating surface of the thermoelectric device to convert some of the liquefied gas to a vapor state. Liquefied gas vapor and/or liquid phase may be supplied by disclosed apparatus and methods. The apparatus may also be used as a vapor pump or a liquid pump, or fluid pump. Methods of operation are also disclosed.

  19. Heterodyne method for high specificity gas detection.

    NASA Technical Reports Server (NTRS)

    Dimeff, J.; Donaldson, R. W.; Gunter, W. D., Jr.; Jaynes, D. N.; Margozzi, A. P.; Deboo, G. J.; Mcclatchie, E. A.; Williams, K. G.

    1971-01-01

    This paper describes a new technique for measuring trace quantities of gases. The technique involves the use of a reference cell (containing a known amount of the gas being sought) and a sample cell (containing an unknown amount of the same gas) wherein the gas densities are modulated. Light passing through the two cells in sequence is modulated in intensity at the vibrational-rotational lines characteristic of the absorption spectrum for the gas of interest. Since the absorption process is nonlinear, modulating the two absorption cells at two different frequencies gives rise to a heterodyning effect, which in turn introduces sum and difference frequencies in the detected signal. Measuring the ratio of the difference frequency signal for example, to the signal introduced by the reference cell provides a normalized measure of the amount of the gas in the sample cell. The readings produced are thereby independent of source intensity, window transparency, and detector sensitivity. Experimental evaluation of the technique suggests that it should be applicable to a wide range of gases, that it should be able to reject spurious signals due to unwanted gases, and that it should be sensitive to concentrations of the order of 10 to the minus 8th power when used with a sample cell of only 20 cm length.

  20. Flue gas desulfurization method and apparatus

    DOEpatents

    Madden, Deborah A. (Canfield, OH); Farthing, George A. (Washington Township, Stark County, OH)

    1998-08-18

    A combined furnace limestone injection and dry scrubber flue gas desulfurization (FGD) system collects solids from the flue gas stream in first particulate collection device located downstream of an outlet of a convection pass of the furnace and upstream of the dry scrubber. The collected solids are diverted to the dry scrubber feed slurry preparation system to increase sulfur oxide species removal efficiency and sorbent utilization. The level of lime in the feed slurry provided to the dry scrubber is thus increased, which enhances removal of sulfur oxide species in the dry scrubber. The decreased particulate loading to the dry scrubber helps maintain a desired degree of free moisture in the flue gas stream entering the dry scrubber, which enhances sulfur oxide species removal both in the dry scrubber and downstream particulate collector, normally a baghouse.

  1. Flue gas desulfurization method and apparatus

    DOEpatents

    Madden, Deborah A. (Canfield, OH); Farthing, George A. (Washington Township, OH)

    1998-09-29

    A combined furnace limestone injection and dry scrubber flue gas desulfurization (FGD) system collects solids from the flue gas stream in first particulate collection device located downstream of an outlet of a convection pass of the furnace and upstream of the dry scrubber. The collected solids are diverted to the dry scrubber feed slurry preparation system to increase sulfur oxide species removal efficiency and sorbent utilization. The level of lime in the feed slurry provided to the dry scrubber is thus increased, which enhances removal of sulfur oxide species in the dry scrubber. The decreased particulate loading to the dry scrubber helps maintain a desired degree of free moisture in the flue gas stream entering the dry scrubber, which enhances sulfur oxide species removal both in the dry scrubber and downstream particulate collector, normally a baghouse.

  2. Method for nonlinear optimization for gas tagging and other systems

    DOEpatents

    Chen, Ting (Chicago, IL); Gross, Kenny C. (Bolingbrook, IL); Wegerich, Stephan (Glendale Heights, IL)

    1998-01-01

    A method and system for providing nuclear fuel rods with a configuration of isotopic gas tags. The method includes selecting a true location of a first gas tag node, selecting initial locations for the remaining n-1 nodes using target gas tag compositions, generating a set of random gene pools with L nodes, applying a Hopfield network for computing on energy, or cost, for each of the L gene pools and using selected constraints to establish minimum energy states to identify optimal gas tag nodes with each energy compared to a convergence threshold and then upon identifying the gas tag node continuing this procedure until establishing the next gas tag node until all remaining n nodes have been established.

  3. Method for nonlinear optimization for gas tagging and other systems

    DOEpatents

    Chen, T.; Gross, K.C.; Wegerich, S.

    1998-01-06

    A method and system are disclosed for providing nuclear fuel rods with a configuration of isotopic gas tags. The method includes selecting a true location of a first gas tag node, selecting initial locations for the remaining n-1 nodes using target gas tag compositions, generating a set of random gene pools with L nodes, applying a Hopfield network for computing on energy, or cost, for each of the L gene pools and using selected constraints to establish minimum energy states to identify optimal gas tag nodes with each energy compared to a convergence threshold and then upon identifying the gas tag node continuing this procedure until establishing the next gas tag node until all remaining n nodes have been established. 6 figs.

  4. Gas migration modeling improves volumetric method of well control

    SciTech Connect

    Leach, C.P.; Quentin, K.M. (Well Control and Systems Design, Houston, TX (United States))

    1994-12-26

    In the volumetric method, gas expansion during gas migration is allowed for by bleeding small quantities of fluid through the choke. When gas first reaches the choke, the influx is distributed near the surface in the annulus. Rapid gas migration then occurs, and mud and gas may need to be bled to maintain constant bottom hole pressure. The volumetric method is a technique for controlling gas kicks when circulation is not possible. The industry-recognized method is based on simple calculations which assume a single bubble of gas, the classic kick. This technique can now be evaluated by using more realistic, deterministic kick models. The results from such models cast double on some of the conventional procedures taught and used in the industry. This article details the analysis of influx behavior following a typical volumetric method. Numerical modeling of fluid losses as the surface pressure rises, gas migration, and dispersion are included to correspond accurately with field observations of kicks. Revised procedures are suggested to deal with these events better, such that the goals of the volumetric method are still attained.

  5. Evaporation of forsterite in the primordial solar nebula; rates and accompanied isotopic fractionation

    Microsoft Academic Search

    Akira Tsuchiyama; Shogo Tachibana; Toshio Takahashi

    1999-01-01

    Evaporation rates of forsterite in the primordial solar nebula were modeled. There are 3 evaporation regimes expected: 1. free evaporation-dominated (FED) regime, where forsterite evaporates as free evaporation, 2. hydrogen reaction-dominated (HRD) regime, where the evaporation is affected by H2 gas, and 3. H2O\\/H2 buffer-dominated (HBD) regime, where the evaporation is controlled by redox states buffered by the H2O\\/H2 ratio

  6. Endwall Treatment and Method for Gas Turbine

    NASA Technical Reports Server (NTRS)

    Hathaway, Michael D. (Inventor); Strazisar, Anthony J. (Inventor); Suder, Kenneth L. (Inventor)

    2006-01-01

    An endwall treatment for a gas turbine engine having at least one rotor blade extending from a rotatable hub and a casing circumferentially surrounding the rotor and the hub, the endwall treatment including, an inlet formed in an endwall of the gas turbine engine adapted to ingest fluid from a region of a higher-pressure fluid, an outlet formed in the endwall and located in a region of lower pressure than the inlet, wherein the inlet and the outlet are in a fluid communication with each other, the outlet being adapted to inject the fluid from the inlet in the region of lower pressure, and wherein the outlet is at least partially circumferentially offset relative to the inlet.

  7. Method for removal of sulfur compounds from a gas stream

    SciTech Connect

    Frech, K.J.; Tazuma, J.J.

    1982-01-19

    This invention relates to a process for the removal of sulfur compounds from a gas stream. More specifically, this invention relates to an improvement in the iron oxide method of sulfur removal from a gas stream through the use of hydrogen peroxide.

  8. Synthesis on evaporation partitioning using stable isotopes

    NASA Astrophysics Data System (ADS)

    Coenders-Gerrits, Miriam; Bogaard, Thom; Wenninger, Jochen; Jonson Sutanto, Samuel

    2015-04-01

    Partitioning of evaporation into productive (transpiration) and non-productive evaporation (interception, soil evaporation) is of highest importance for water management practices, irrigation scheme design, and climate modeling. Despite this urge, the magnitude of the ratio of transpiration over total evaporation is still under debate and poorly understood due to measuring difficulties. However, with the current development in isotope measuring devices, new opportunities arise to untangle the partitioning of evaporation. In this paper we synthesize the opportunities and limitations using stable water isotopes in evaporation partitioning. We will analyze a set of field as well as laboratory studies to demonstrate the different evaporation components for various climate and vegetation conditions using stable isotopes 18O/16O and 2H/1H. Experimental data on evaporation partitioning of crops, grass, shrubs and trees are presented and we will discuss the specific experimental set-ups and data collection methods. The paper will be a synthesis of these studies.

  9. A Gas-Kinetic Method for Hyperbolic-Elliptic Equations and Its Application in Two-Phase Fluid Flow

    NASA Technical Reports Server (NTRS)

    Xu, Kun

    1999-01-01

    A gas-kinetic method for the hyperbolic-elliptic equations is presented in this paper. In the mixed type system, the co-existence and the phase transition between liquid and gas are described by the van der Waals-type equation of state (EOS). Due to the unstable mechanism for a fluid in the elliptic region, interface between the liquid and gas can be kept sharp through the condensation and evaporation process to remove the "averaged" numerical fluid away from the elliptic region, and the interface thickness depends on the numerical diffusion and stiffness of the phase change. A few examples are presented in this paper for both phase transition and multifluid interface problems.

  10. DWPF Recycle Evaporator Shielded Cells Testing

    Microsoft Academic Search

    T. L. Fellinger; D. T. Herman; M. E Stone

    2005-01-01

    Testing was performed to determine the feasibility and processing characteristics of evaporation of actual Defense Waste Processing Facility (DWPF) recycle material. Samples of the Off Gas Condensate Tank (OGCT) and Slurry Mix Evaporator Condensate Tank (SMECT) were transferred from DWPF to the Savannah River National Lab (SRNL) Shielded Cells and blended with De-Ionized (DI) water and a small amount of

  11. Isothermal Gas-liquid Flow Using the Lattice Boltzmann Method

    E-print Network

    Kim, Donghoon

    2012-10-19

    ISOTHERMAL GAS-LIQUID FLOW USING THE LATTICE BOLTZMANN METHOD A Thesis by DONGHOON KIM Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 2011 Major Subject: Nuclear Engineering ISOTHERMAL GAS-LIQUID FLOW USING THE LATTICE BOLTZMANN METHOD A Thesis by DONGHOON KIM Submitted to the Office of Graduate Studies of Texas A&M University...

  12. Evaporation from the reservoir of the High Aswan Dam, Egypt: A new comparison of relevant methods with limited data

    Microsoft Academic Search

    M. F. Sadek; M. M. Shahin; C. J. Stigter

    1997-01-01

    Previous estimates of average annual evaporation from the lake formed by the High Dam at Aswan, Egypt, fall in the range from 4.65 mm d-1 to 7.95 mm d-1. The difference between these limits, more than 7 billion m3 yr-1 at the highest storage level, is nearly one-eighth the share by treaty of Egypt, and more than one-third of the

  13. Turbulence And Evaporation In Clusters Of Drops

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Harstad, Kenneth G.

    1989-01-01

    Report presents theoretical model of evaporation of cluster of drops of single-component liquid fuel in and of processes of exchange between cluster and gas surrounding it. Formulation of model has three components: description of conservation of mass, molecular species, and enthalpy in sphere of influence of each drop; description of conservation of mass, molecular species, and enthalpy in cluster volume; description of convective effects by use of differential equations expressing conservation of momentum for gases and drops. Results obtained from analysis show turbulence enhances evaporation and controlling factor in evaporation of very dense clusters. Practical implication of findings evaporation of fuel controlled more readily near fuel injector than farther along combustor.

  14. Gas chromatograph method for the determination of gas solubility in liquids

    SciTech Connect

    Horvath, M.J.; Sebastian, H.M.; Chao, K.C.

    1981-11-01

    A new method has been developed for the determination of gas solubility in a liquid by saturating the liquid with a bubbling stream of gas and analyzing the saturated liquid with a gas chromatograph. This simple method has been applied to CO/sub 2/ dissolved in benzene, toluene, m-xylene, diphenylmethane, and 1-methylnaphthalene for the purpose of checking with literature data, and the results are good. New data are presented for CO/sub 2/ in n-decane, tetralin, m-cresol, and quinoline.

  15. Laboratory Methods For The Investigation of Gas Hydrates

    NASA Astrophysics Data System (ADS)

    Kulenkampff, J.; Spangenberg, E.

    Sediments in gas hydrate zones are complex composites of solid material and fluids. They may consist of unconsolidated sediments, gas hydrate, water or ice, and gas, depending on hydrostatic pressure and temperature, the sediment type, and genesis. Therefore, petrophysical properties as ultrasonic velocities and electrical resistivity, as well as porosity and permeability may vary within a broad range, and estimates of the gas content and models of gas hydrate deposits are very problematic. Evaluation methods for logging and geophysical field data in gas hydrate deposits are not yet available. This is due to the lack of laboratory measurements of physical pa- rameters in relation to the gas content and the sediment type. Standard interpretation methods have been applied with questionable success. Thus a transportable laboratory system (FLECAS: field laboratory experimental core analysis system) has been developed at the GFZ for the investigation of hydrate bear- ing cores. It consists of a thermostatted vessel (-10C to 60C) with pressure control (max. 70 MPa) and measurement setups for pore volume, sample volume, permeabil- ity, electrical resistivity, ultrasonic compressional and shear wave velocity. Measurements were done on synthetic gas hydrate bearing sands: During the temper- ature increase at first the frozen water melts, resulting in a decrease of resistivity and velocity. A further decrease in pressure causes the hydrate to dissociate, which tem- porarily decreases the temperature, and then again resistivity and velocity decrease, because water is released. At last the material looses its mechanical strength. Presently the system is used for core analysis of naturally occurring gas hydrates in the permafrost region at the Mallik gas hydrate production test well in Canada.

  16. TOWARDS A HYBRID MONTE CARLO METHOD FOR RAREFIED GAS DYNAMICS

    E-print Network

    Pareschi, Lorenzo

    TOWARDS A HYBRID MONTE CARLO METHOD FOR RAREFIED GAS DYNAMICS RUSSEL E. CAFLISCH #3; AND LORENZO PARESCHI y Abstract. For the Boltzmann equation, we present a hybrid Monte Carlo method that is robust-equilibrium particle distribution and a Maxwellian. The hybrid distribution is then evolved by Monte Carlo

  17. A new gas dilution method for measuring body volume.

    PubMed Central

    Nagao, N; Tamaki, K; Kuchiki, T; Nagao, M

    1995-01-01

    This study was designed to examine the validity of a new gas dilution method (GD) for measuring human body volume and to compare its accuracy with the results obtained by the underwater weighing method (UW). We measured the volume of plastic bottles and 16 subjects (including two females), aged 18-42 years with each method. For the bottles, the volume measured by hydrostatic weighing was correlated highly (r = 1.000) with that measured by the new gas dilution method. For the subjects, the body volume determined by the two methods was significantly correlated (r = 0.998). However, the subject's volume measured by the gas dilution method was significantly larger than that by underwater weighing method. There was significant correlation (r = 0.806) between GD volume-UW volume and the body mass index (BMI), so that UW volume could be predicted from GD volume and BMI. It can be concluded that the new gas dilution method offers promising possibilities for future research in the population who cannot submerge underwater. PMID:7551760

  18. EVALUATION OF STATIONARY SOURCE PARTICULATE MEASUREMENT METHODS. VOLUME III. GAS TEMPERATURE CONTROL DURING METHOD 5 SAMPLING

    EPA Science Inventory

    A study was conducted to measure changes in gas temperature along the length of a Method 5 sampling train due to variations in stack gas temperature, sampling rate, filter box temperature and method for controlling the probe heating element. For each run condition, temperatures w...

  19. Exhaust gas recirculation method for internal combustion engines

    SciTech Connect

    Kawanabe, T.; Kimura, K.; Asakura, M.; Shiina, T.

    1988-07-19

    This patent describes a method of controlling exhaust gas recirculation in an internal combustion engine having an exhaust passage, an intake passage, an exhaust gas recirculating passage communicating the exhaust passage with the intake passage, and exhaust gas recirculating valve; and a transmission having a shift lever. The valve opening of the exhaust gas recirculating valve is controlled in response to operating conditions of the engine so as to regulate the amount of exhaust gas recirculation to values appropriate to the operating conditions of the engine. The method comprising the steps of (1) determining whether or not the engine is in at least one of a predetermined accelerating condition and a predetermined decelerating condition; (2) varying the valve opening of the exhaust gas recirculating valve by a predetermined value when the engine is determined to be in at least one of the predetermined accelerating condition and the predetermined decelerating condition; (3) detecting a position of the shift lever of the transmission; and (4) correcting the predetermined value in accordance with the detected position of the shift lever so as to increase the valve opening of the exhaust gas recirculating valve as the shift lever of the transmission is set to a higher speed position.

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

    NASA Technical Reports Server (NTRS)

    Martini, W. R.

    1986-01-01

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

  1. Effects of gold catalysts and thermal evaporation method modifications on the growth process of Zn{sub 1-x}Mg{sub x}O nanowires

    SciTech Connect

    Yousefi, Ramin, E-mail: yousefi.ramin@gmail.co [Solid State Laboratory, Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Department of Physics, Islamic Azad University, Masjed-Soleiman Branch, Masjed-Soleiman (Iran, Islamic Republic of); Muhamad, Muhamad Rasat [Solid State Laboratory, Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2010-07-15

    In this paper, we investigate the roles of gold catalysts and thermal evaporation method modifications in the growth process of Zn{sub 1-x}Mg{sub x}O nanowires. Zn{sub 1-x}Mg{sub x}O nanowires are fabricated on silicon substrates with and without using a gold catalyst. Characterizations reveal that Mg acts in a self-catalyst role during the growth process of Zn{sub 1-x}Mg{sub x}O nanowires grown on catalyst-free substrate. The optical properties and crystalline quality of the Zn{sub 1-x}Mg{sub x}O nanowires are characterized by room temperature photoluminescence (PL) measurements and Raman spectroscopy, respectively. The Raman and PL studies demonstrate that the Zn{sub 1-x}Mg{sub x}O nanowires grown using the catalyst-free method have good crystallinity with excellent optical properties and have a larger band-gap in comparison to those grown with the assistance of gold. - Graphical abstract: ZnMgO nanowires can be formed with and without gold catalyst by a modified thermal evaporation method.

  2. Synthesis Methods, Microscopy Characterization and Device Integration of Nanoscale Metal Oxide Semiconductors for Gas Sensing in Aerospace Applications

    NASA Technical Reports Server (NTRS)

    VanderWal, Randy L.; Berger, Gordon M.; Kulis, Michael J.; Hunter, Gary W.; Xu, Jennifer C.; Evans, Laura J.

    2009-01-01

    A comparison is made between SnO2, ZnO, and TiO2 single-crystal nanowires and SnO2 polycrystalline nanofibers for gas sensing. Both nanostructures possess a one-dimensional morphology. Different synthesis methods are used to produce these materials: thermal evaporation-condensation (TEC), controlled oxidation, and electrospinning. Advantages and limitations of each technique are listed. Practical issues associated with harvesting, purification, and integration of these materials into sensing devices are detailed. For comparison to the nascent form, these sensing materials are surface coated with Pd and Pt nanoparticles. Gas sensing tests, with respect to H2, are conducted at ambient and elevated temperatures. Comparative normalized responses and time constants for the catalyst and noncatalyst systems provide a basis for identification of the superior metal-oxide nanostructure and catalyst combination. With temperature-dependent data, Arrhenius analyses are made to determine an activation energy for the catalyst-assisted systems.

  3. Method for eliminating gas blocking in electrokinetic pumping systems

    DOEpatents

    Arnold, Don W. (Livermore, CA); Paul, Phillip H. (Livermore, CA); Schoeniger, Joseph S. (Oakland, CA)

    2001-09-11

    A method for eliminating gas bubble blockage of current flow during operation of an electrokinetic pump. By making use of the ability to modify the surface charge on the porous dielectric medium used in electrokinetic pumps, it becomes possible to place electrodes away from the pressurized region of the electrokinetic pump. While gas is still generated at the electrodes they are situated such that the generated gas can escape into a larger buffer reservoir and not into the high pressure region of the pump where the gas bubbles can interrupt current flow. Various combinations of porous dielectric materials and ionic conductors can be used to create pumps that have desirable electrical, material handling, and flow attributes.

  4. Methods for gas detection using stationary hyperspectral imaging sensors

    DOEpatents

    Conger, James L. (San Ramon, CA); Henderson, John R. (Castro Valley, CA)

    2012-04-24

    According to one embodiment, a method comprises producing a first hyperspectral imaging (HSI) data cube of a location at a first time using data from a HSI sensor; producing a second HSI data cube of the same location at a second time using data from the HSI sensor; subtracting on a pixel-by-pixel basis the second HSI data cube from the first HSI data cube to produce a raw difference cube; calibrating the raw difference cube to produce a calibrated raw difference cube; selecting at least one desired spectral band based on a gas of interest; producing a detection image based on the at least one selected spectral band and the calibrated raw difference cube; examining the detection image to determine presence of the gas of interest; and outputting a result of the examination. Other methods, systems, and computer program products for detecting the presence of a gas are also described.

  5. Convergence of the viscosity method for isentropic gas dynamics

    Microsoft Academic Search

    Ronald J. DiPerna

    1983-01-01

    A convergence theorem for the method of artificial viscosity applied to the isentropic equations of gas dynamics is established. Convergence of a subsequence in the strong topology is proved without uniform estimates on the derivatives using the theory of compensated compactness and an analysis of progressing entropy waves.

  6. Measurement of gas diffusion through soils: comparison of laboratory methods.

    PubMed

    Allaire, Suzanne E; Lafond, Jonathan A; Cabral, Alexandre R; Lange, Sébastien F

    2008-11-01

    Gas movement through soils is important for ecosystems and engineering in many ways such as for microbial and plant respiration, passive methane oxidation in landfill covers and oxidation of mine residues. Diffusion is one of the most important gas movement processes and the determination of the diffusion coefficient is a crucial step in any study. Five laboratory methods used for measuring the relative gas diffusion coefficient (D(s)/D(o)) were compared using a loamy sand, a porous media commonly found in agricultural fields and in several engineered structures, such as in landfill final covers. In the absence of macropores, all methods gave rather similar values of D(s)/D(o). Methods allowing the study of microscale variability indicated that the presence of macropores highly influenced gas movement, thus the value of D(s)/D(o), which, near a macropore may be one order of magnitude higher than in regions without macropores. Repacked columns do not allow the study of heterogeneity in D(s)/D(o). Natural spatial variability in D(s)/D(o) due to water distribution and preferential pathways can only be studied in large systems, but these systems are difficult to handle. Advantages and disadvantages of each method are discussed. PMID:18974902

  7. Aircraft Engine Gas Path Diagnostic Methods: Public Benchmarking Results

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Borguet, Sebastien; Leonard, Olivier; Zhang, Xiaodong (Frank)

    2013-01-01

    Recent technology reviews have identified the need for objective assessments of aircraft engine health management (EHM) technologies. To help address this issue, a gas path diagnostic benchmark problem has been created and made publicly available. This software tool, referred to as the Propulsion Diagnostic Method Evaluation Strategy (ProDiMES), has been constructed based on feedback provided by the aircraft EHM community. It provides a standard benchmark problem enabling users to develop, evaluate and compare diagnostic methods. This paper will present an overview of ProDiMES along with a description of four gas path diagnostic methods developed and applied to the problem. These methods, which include analytical and empirical diagnostic techniques, will be described and associated blind-test-case metric results will be presented and compared. Lessons learned along with recommendations for improving the public benchmarking processes will also be presented and discussed.

  8. The repair and rehabilitation method of Tokyo gas

    SciTech Connect

    Yagi, Shuichi [Tokyo Gas Co., Ltd. (Japan)

    1996-08-01

    It has been an important matter for gas utilities to maintain their pipelines easily and economically. But pipes that have become old suffer from progressive corrosion, and as a result of vibration caused by traffic or the effects of land subsidence, joints can become loosened. To repair pipes that have suffered in such ways, the usual method to do is to dig them up and replace them with new ones. But this method requires a large amount of excavation, so the work takes a long time to complete and is costly. To deal with these problems, Tokyo Gas developed number of repair and rehabilitation methods to permit renewal of pipelines without replacing them. In this paper, I would like to introduce our repair and rehabilitation methods for low-pressure pipeline. 4 refs., 9 figs., 4 tabs.

  9. Particle-gas Dynamics with Athena: Method and Convergence

    NASA Astrophysics Data System (ADS)

    Bai, Xue-Ning; Stone, James M.

    2010-10-01

    The Athena magnetohydrodynamics code has been extended to integrate the motion of particles coupled with the gas via aerodynamic drag in order to study the dynamics of gas and solids in protoplanetary disks (PPDs) and the formation of planetesimals. Our particle-gas hybrid scheme is based on a second-order predictor-corrector method. Careful treatment of the momentum feedback on the gas guarantees exact conservation. The hybrid scheme is stable and convergent in most regimes relevant to PPDs. We describe a semi-implicit integrator generalized from the leap-frog approach. In the absence of drag force, it preserves the geometric properties of a particle orbit. We also present a fully implicit integrator that is unconditionally stable for all regimes of particle-gas coupling. Using our hybrid code, we study the numerical convergence of the nonlinear saturated state of the streaming instability. We find that gas flow properties are well converged with modest grid resolution (128 cells per pressure length ?r for dimensionless stopping time ? s = 0.1) and an equal number of particles and grid cells. On the other hand, particle clumping properties converge only at higher resolutions, and finer resolution leads to stronger clumping before convergence is reached. Finally, we find that the measurement of particle transport properties resulted from the streaming instability may be subject to error of about ±20%.

  10. Control method for mixed refrigerant based natural gas liquefier

    DOEpatents

    Kountz, Kenneth J. (Palatine, IL); Bishop, Patrick M. (Chicago, IL)

    2003-01-01

    In a natural gas liquefaction system having a refrigerant storage circuit, a refrigerant circulation circuit in fluid communication with the refrigerant storage circuit, and a natural gas liquefaction circuit in thermal communication with the refrigerant circulation circuit, a method for liquefaction of natural gas in which pressure in the refrigerant circulation circuit is adjusted to below about 175 psig by exchange of refrigerant with the refrigerant storage circuit. A variable speed motor is started whereby operation of a compressor is initiated. The compressor is operated at full discharge capacity. Operation of an expansion valve is initiated whereby suction pressure at the suction pressure port of the compressor is maintained below about 30 psig and discharge pressure at the discharge pressure port of the compressor is maintained below about 350 psig. Refrigerant vapor is introduced from the refrigerant holding tank into the refrigerant circulation circuit until the suction pressure is reduced to below about 15 psig, after which flow of the refrigerant vapor from the refrigerant holding tank is terminated. Natural gas is then introduced into a natural gas liquefier, resulting in liquefaction of the natural gas.

  11. Method of making gas diffusion layers for electrochemical cells

    DOEpatents

    Frisk, Joseph William (Oakdale, MN); Boand, Wayne Meredith (Lino Lakes, MN); Larson, James Michael (Saint Paul, MN)

    2002-01-01

    A method is provided for making a gas diffusion layer for an electrochemical cell comprising the steps of: a) combining carbon particles and one or more surfactants in a typically aqueous vehicle to make a preliminary composition, typically by high shear mixing; b) adding one or more highly fluorinated polymers to said preliminary composition by low shear mixing to make a coating composition; and c) applying the coating composition to an electrically conductive porous substrate, typically by a low shear coating method.

  12. Laboratory-scale experiments applied to the design of a two-stage submerged combustion evaporation system

    Microsoft Academic Search

    Dongbei Yue; Yudong Xu; Rasool Bux Mahar; Fuqiang Liu; Yongfeng Nie

    2007-01-01

    To simulate a submerged combustion evaporation (SCE) process under laboratory conditions, this study conducted three kinds of indirect-heating evaporation experiments, including normal evaporation, vacuum evaporation, and gas-carrying evaporation experiments on mature municipal solid waste (MSW) landfill leachate. The results showed that the organic concentrations in terms of COD in condensates were always very high at the beginning, then decreased rapidly,

  13. Evaporator Cleaning Studies

    SciTech Connect

    Wilmarth, W.R.

    1999-04-15

    Operation of the 242-16H High Level Waste Evaporator proves crucial to liquid waste management in the H-Area Tank Farm. Recent operational history of the Evaporator showed significant solid formation in secondary lines and in the evaporator pot. Additional samples remain necessary to ensure material identity in the evaporator pot. Analysis of these future samples will provide actinide partitioning information and dissolution characteristics of the solid material from the pot to ensure safe chemical cleaning.

  14. Evaporative cooling in insects

    Microsoft Academic Search

    Henry D. Prange

    1996-01-01

    Insects commonly use behavior to avoid the heat stress and consequent water loss of hot environments. It has been assumed by many to be impossible or impractical for insects to employ evaporative cooling. Despite this assumption, there have been many instances, historically and recently where insects are reported to survive otherwise lethal temperatures by evaporating water. The site of evaporation

  15. Segmented inlet nozzle for gas turbine, and methods of installation

    DOEpatents

    Klompas, Nicholas (Scotia, NY)

    1985-01-01

    A gas turbine nozzle guide vane assembly is formed of individual arcuate nozzle segments. The arcuate nozzle segments are elastically joined to each other to form a complete ring, with edges abutted to prevent leakage. The resultant nozzle ring is included within the overall gas turbine stationary structure and secured by a mounting arrangement which permits relative radial movement at both the inner and outer mountings. A spline-type outer mounting provides circumferential retention. A complete rigid nozzle ring with freedom to "float" radially results. Specific structures are disclosed for the inner and outer mounting arrangements. A specific tie-rod structure is also disclosed for elastically joining the individual nozzle segments. Also disclosed is a method of assembling the nozzle ring subassembly-by-subassembly into a gas turbine employing temporary jacks.

  16. A diagram for the evaporation status of extrasolar planets

    E-print Network

    A. Lecavelier des Etangs

    2006-09-27

    To describe the evaporation status of the extrasolar planets, we propose to consider an energy diagram in which the potential energy of the planets is plotted versus the energy received by the upper atmosphere. Here we present a basic method to estimate these quantities. For the potential energy, we include the modification of the gravity field by the tidal forces from the parent stars. This description allows a quick estimate of both the escape rate of the atmospheric gas and the lifetime of a planet against the evaporation process. In the energy diagram, we find an evaporation-forbidden region in which a gaseous planet would evaporate in less than 5 billion years. With their observed characteristics, all extrasolar planets are found outside this evaporation-forbidden region. The escape rates are estimated to be in the range 10^5 g/s to 10^{12} g/s, with few cases above 10^{11} g/s. The estimated escape rate for HD209458b is found to be consistent with the lower limit of 10^{10} g/s obtained from interpretation of the HI Lyman-alpha observations. Finally, this diagram suggests possibilities for the nature of the recently discovered Neptune-mass planets. We find that GJ436b, 55Cnc_e and HD69830b cannot be low mass gaseous planets. With density necessarily above 0.5g/cm3 to survive evaporation, these planets must contain a large fraction of solid/liquid material. Concerning GJ876d, we find that it must have a density larger than ~3g/cm3 to survive the strong EUV energy flux from its nearby parent star. GJ876d must contain a large fraction of massive elements.

  17. Evaporative cooling of air in impinging streams

    Microsoft Academic Search

    B. Yao; Y. Berman; A. Tamir

    1995-01-01

    An experimental study was conducted on evaporative cooling of air in an impinging-stream reactor, in which two droplet gas streams flow in opposite directions and meet in the impingement zone. The air was cooled by evaporation of water droplets. Volumetric heat-transfer coefficients h{sub v} determined enabled the authors to evaluate the performance of the cooler. Maximum values of h{sub v}

  18. Thickness and temperature dependence of electrical resistivity of p-type Bi0.5Sb1.5Te3 thin films prepared by flash evaporation method

    NASA Astrophysics Data System (ADS)

    Duan, Xingkai; Yang, Junyou; Zhu, W.; Fan, X. A.; Bao, S. Q.

    2006-12-01

    P-type Bi0.5Sb1.5Te3 thin films with thicknesses in the range 80-320 nm have been deposited by the flash evaporation method on glass substrates at 473 K. XRD and field emission scanning electron microscope were performed to characterize the thin films. The results show that the thin films are polycrystalline and the grain size of the thin films increases with increasing thickness of the thin films. Compositional analysis of the thin films was also carried out by energy-dispersive x-ray analysis. A near linear relationship was observed between the electrical resistivity and the inverse thickness of the annealed thin films, and it agrees with Tellier's model. Electrical resistivity of the annealed thin films was studied in the temperature range 300-350 K, and their thermal activation behaviour was characterized, the activation energy for conduction decreases with increasing thickness of the thin films.

  19. Preparation of PbTiO3 Films Utilizing Self-Control Mechanism of Stoichiometric Composition in Dual-Beam Vacuum Evaporation Method

    NASA Astrophysics Data System (ADS)

    Ueno, Satoshi; Ishiwara, Hiroshi

    1992-09-01

    Optimum conditions for preparing PbTiO3 films on Si and SrTiO3 substrates are investigated in the dual-beam vacuum evaporation method using PbO and TiO2. It has been found that tetragonal PbTiO3 films are formed on Si substrates at temperatures ranging from 550°C to 600°C, and that the stoichiometric composition of the films is easily obtained at 600°C by supplying excess PbO molecules to the substrate. It has also been found that PbTiO3 films grow epitaxially on SrTiO3 substrates at temperatures around 550°C.

  20. Rate of runaway evaporative cooling

    SciTech Connect

    Groep, J. van de; Straten, P. van der; Vogels, J. M. [Atom Optics and Ultrafast Dynamics, Utrecht University, P.O. Box 80, 000, NL-3508 TA Utrecht (Netherlands)

    2011-09-15

    Evaporative cooling is a process that is essential in creating Bose-Einstein condensates in dilute atomic gasses. This process has often been simulated based on a model using a truncated Boltzmann distribution. This model assumes that the energy distribution up to the threshold energy can still be described by a Boltzmann distribution: it assumes detailed balance up to the threshold energy. However, the evolution of the distribution function in time is not taken into account. Here we solve the kinetic Boltzmann equation for a gas undergoing evaporative cooling in a harmonic and linear trap in order to determine the evolution of the energy distribution. The magnitude of the discrepancy with the truncated Boltzmannmodel is calculated by including a polynomial expansion of the distribution function. We find that up to 35% fewer particles are found in the high-energy tail of the distribution with respect to the truncated Boltzmann distribution and up to 15% more collisions are needed to reach quantum degeneracy. Supported by a detailed investigation of the particle loss rate at different energies, we conclude that the limited occupation of high-energy states during the evaporation process causes the lowering of the evaporation speed and efficiency.

  1. A comparative study on pure, L-arginine and glycine doped ammonium dihydrogen orthophosphate single crystals grown by slow solvent evaporation and temperature-gradient method

    NASA Astrophysics Data System (ADS)

    Pattanaboonmee, N.; Ramasamy, P.; Yimnirun, R.; Manyum, P.

    2011-01-01

    Single crystals of pure, L-arginine and glycine doped ammonium dihydrogen orthophosphate (ADP) were grown by both the slow solvent evaporation method and the temperature-gradient method of Sankaranarayanan-Ramasamy (SR). The metastable zone width for different saturation temperatures of pure glycine and L-arginine added solutions were carried out. The grown crystals were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), optical transmission, dielectric constant, dielectric loss, and Vickers microhardness. The DSC and TG curves of the grown crystals indicated that they were stable up to 200 °C. The XRD study confirmed the structure of the grown crystal. The optical transmission analysis revealed that the pure and doped ADP crystals had very high percentage of transmission in the entire visible region. The important optical parameters such as reflectance and extinction coefficients of the grown crystals were calculated. L-arginine and glycine were used as dopants to reduce dielectric constant of ADP. The a.c. resistivity and a.c. conductivity were calculated. Dielectric loss of the doped ADP crystals grown by the SR method is lower than the doped ADP crystals grown by the conventional method. Larger hardness value for the SR method grown crystals confirmed greater crystalline perfection.

  2. A novel method of measuring electrophoretic mobility of gas bubbles.

    PubMed

    Najafi, Aref Seyyed; Drelich, Jaroslaw; Yeung, Anthony; Xu, Zhenghe; Masliyah, Jacob

    2007-04-15

    Accurate measurement of electrophoretic mobility for gas bubbles is a challenging task as it requires the creation of a desired number of very small air bubbles to ensure negligible rise velocities during the course of the measurement. Here, we report a simple and reliable method for generating stable dispersions of "nano-bubbles." Preparation of such dispersions relies on the nucleation of nano-bubbles in solutions supersaturated with gas. Electrophoretic mobility of these nano-bubbles is determined by the ZetaPALS technique (Brookhaven Instruments) using Uzgiris electrodes coated with palladium. The Smoluchowski limit is assumed in the calculation of zeta potentials. In regard to reproducibility and reliability, this novel method shows a clear advantage over other existing techniques of zeta potential measurement for bubbles. PMID:17257614

  3. Application of the parallel multicanonical method to lattice gas condensation

    NASA Astrophysics Data System (ADS)

    Zierenberg, Johannes; Wiedenmann, Micha; Janke, Wolfhard

    2014-05-01

    We present the speedup from a novel parallel implementation of the multicanonical method on the example of a lattice gas in two and three dimensions. In this approach, all cores perform independent equilibrium runs with identical weights, collecting their sampled histograms after each iteration in order to estimate consecutive weights. The weights are then redistributed to all cores. These steps are repeated until the weights are converged. This procedure benefits from a minimum of communication while distributing the necessary amount of statistics efficiently. Using this method allows us to study a broad temperature range for a variety of large and complex systems. Here, a gas is modeled as particles on the lattice, which interact only with their nearest neighbors. For a fixed density this model is equivalent to the Ising model with fixed magnetization. We compare our results to an analytic prediction for equilibrium droplet formation, confirming that a single macroscopic droplet forms only above a critical density.

  4. Method and apparatus for controlling gas evolution from chemical reactions

    DOEpatents

    Skorpik, J.R.; Dodson, M.G.

    1999-05-25

    The present invention is directed toward monitoring a thermally driven gas evolving chemical reaction with an acoustic apparatus. Signals from the acoustic apparatus are used to control a heater to prevent a run-away condition. A digestion module in combination with a robotic arm further automate physical handling of sample material reaction vessels. The invention is especially useful for carrying out sample procedures defined in EPA Methods SW-846. 8 figs.

  5. Method and apparatus for controlling gas evolution from chemical reactions

    DOEpatents

    Skorpik, James R. (Kennewick, WA); Dodson, Michael G. (Richland, WA)

    1999-01-01

    The present invention is directed toward monitoring a thermally driven gas evolving chemical reaction with an acoustic apparatus. Signals from the acoustic apparatus are used to control a heater to prevent a run-away condition. A digestion module in combination with a robotic arm further automate physical handling of sample material reaction vessels. The invention is especially useful for carrying out sample procedures defined in EPA Methods SW-846.

  6. Gas phase fractionation method using porous ceramic membrane

    DOEpatents

    Peterson, Reid A. (Madison, WI); Hill, Jr., Charles G. (Madison, WI); Anderson, Marc A. (Madison, WI)

    1996-01-01

    Flaw-free porous ceramic membranes fabricated from metal sols and coated onto a porous support are advantageously used in gas phase fractionation methods. Mean pore diameters of less than 40 .ANG., preferably 5-20 .ANG. and most preferably about 15 .ANG., are permeable at lower pressures than existing membranes. Condensation of gases in small pores and non-Knudsen membrane transport mechanisms are employed to facilitate and increase membrane permeability and permselectivity.

  7. Nanofluid Drop Evaporation: Experiment, Theory, and Modeling

    NASA Astrophysics Data System (ADS)

    Gerken, William James

    Nanofluids, stable colloidal suspensions of nanoparticles in a base fluid, have potential applications in the heat transfer, combustion and propulsion, manufacturing, and medical fields. Experiments were conducted to determine the evaporation rate of room temperature, millimeter-sized pendant drops of ethanol laden with varying amounts (0-3% by weight) of 40-60 nm aluminum nanoparticles (nAl). Time-resolved high-resolution drop images were collected for the determination of early-time evaporation rate (D2/D 02 > 0.75), shown to exhibit D-square law behavior, and surface tension. Results show an asymptotic decrease in pendant drop evaporation rate with increasing nAl loading. The evaporation rate decreases by approximately 15% at around 1% to 3% nAl loading relative to the evaporation rate of pure ethanol. Surface tension was observed to be unaffected by nAl loading up to 3% by weight. A model was developed to describe the evaporation of the nanofluid pendant drops based on D-square law analysis for the gas domain and a description of the reduction in liquid fraction available for evaporation due to nanoparticle agglomerate packing near the evaporating drop surface. Model predictions are in relatively good agreement with experiment, within a few percent of measured nanofluid pendant drop evaporation rate. The evaporation of pinned nanofluid sessile drops was also considered via modeling. It was found that the same mechanism for nanofluid evaporation rate reduction used to explain pendant drops could be used for sessile drops. That mechanism is a reduction in evaporation rate due to a reduction in available ethanol for evaporation at the drop surface caused by the packing of nanoparticle agglomerates near the drop surface. Comparisons of the present modeling predictions with sessile drop evaporation rate measurements reported for nAl/ethanol nanofluids by Sefiane and Bennacer [11] are in fairly good agreement. Portions of this abstract previously appeared as: W. J. Gerken, A. V. Thomas, N. Koratkar and M. A. Oehlschlaeger, Int. J. Heat Mass Transfer, vol. 74, no. 1, pp. 263-268, July 2014. W. J. Gerken, M. A. Oehlschlaeger, "Nanofluid Pendant Droplet Evaporation", in Proceedings of the ASME 2013 Summer Heat Transfer Conference, Minneapolis, MN, 2013, pp. V001T03A018.

  8. Gas/Aerosol partitioning: a simplified method for global modeling

    NASA Astrophysics Data System (ADS)

    Metzger, S. M.

    2000-09-01

    The main focus of this thesis is the development of a simplified method to routinely calculate gas/aerosol partitioning of multicomponent aerosols and aerosol associated water within global atmospheric chemistry and climate models. Atmospheric aerosols are usually multicomponent mixtures, partly composed of acids (e.g. H2SO4, HNO3), their salts (e.g. (NH4)2SO4, NH4NO3, respectively), and water. Because these acids and salts are highly hygroscopic, water, that is associated with aerosols in humid environments, often exceeds the total dry aerosol mass. Both the total dry aerosol mass and the aerosol associated water are important for the role of atmospheric aerosols in climate change simulations. Still, multicomponent aerosols are not yet routinely calculated within global atmospheric chemistry or climate models. The reason is that these particles, especially volatile aerosol compounds, require a complex and computationally expensive thermodynamical treatment. For instance, the aerosol associated water depends on the composition of the aerosol, which is determined by the gas/liquid/solid partitioning, in turn strongly dependent on temperature, relative humidity, and the presence of pre-existing aerosol particles. Based on thermodynamical relations such a simplified method has been derived. This method is based on the assumptions generally made by the modeling of multicomponent aerosols, but uses an alternative approach for the calculation of the aerosol activity and activity coefficients. This alternative approach relates activity coefficients to the ambient relative humidity, according to the vapor pressure reduction and the generalization of Raoult s law. This relationship, or simplification, is a consequence of the assumption that the aerosol composition and the aerosol associated water are in thermodynamic equilibrium with the ambient relative humidity, which determines the solute activity and, hence, activity coefficients of a multicomponent aerosol mixture. Thus, the necessary equilibrium equations can be solved analytically, so that numerical and therefore expensive iterative calculations are avoided. Subsequently, a new thermodynamic gas/aerosol partitioning model has been developed, called EQSAM (Equilibrium Simplified Aerosol Model). EQSAM has been compared with various other thermodynamical models presently in use, which shows that the results of EQSAM are well within the range produced by these more complex models. The application to global modeling further shows that EQSAM is indeed sufficiently fast and accurate. Especially the results of the global gas/aerosol partitioning calculations show that differences resulting from the thermodynamical treatment affect much less the aerosol composition compared to other, non-thermodynamical parameters, such as the model resolution or the boundary layer mixing scheme used. This indicates that the gas/aerosol partitioning calculations in atmospheric chemistry models are largely governed by transport processes, including meteorology, emission sources, as well as wet and dry deposition processes. Modeling results further indicate that gas/aerosol partitioning, especially at lower temperatures (during winter and nights), is of great importance for both the gas phase concentrations and the aerosol composition, including aerosol associated water. For instance, the mean surface gaseous nitric acid concentration is predicted to partition almost completely into the aerosol phase during winter and summer nights. This considerably increases the predicted aerosol load, compared to model calculations excluding gas/aerosol partitioning. This consequently affects the aerosol associated water (because the aerosol water is proportional to the amount of dissolved matter). Additionally, aerosol mass from gas/aerosol partitioning, such as ammonium nitrate, has a longer residence time than the precursor gases (NH3 and HNO3) and might, therefore, be subject to long-range transport from the sources. This is, for example, the case for ammonium nitrate originating from gas-to-particle conversio

  9. Method for cleansing noxious constituents from gas streams

    SciTech Connect

    Schauer, D.J.; Schauer, J.M.

    1982-05-18

    An apparatus and method for chemically altering and scrubbing the noxious constituents from foundry core manufacturing and arc welding operations is disclosed. An upstanding closed container is provided and a gas washing liquid is disposed within the container to a predetermined level. A horizontal baffle is mounted stationarily within the container at an elevation spaced above the level of the gas washing liquid therein and spaced peripheral portions of the baffle are spaced inwardly of the opposing inner surface of the container. A gas drive pipe extends into the container, downwardly past the baffle , and opens downwardly in a central lower portion of the container, below the baffle and near the bottom of the liquid. The container includes a top cover and an outlet duct is provided which opens outwardly of the container through a central portion of the cover. The gases are pumped into the drive pipe to achieve a critical velocity at the exit of the drive pipe of about 2, 300-20,000 linear feet per minu entering the liquid in a substantially vertical downward direction within the critical velocity range, small gascontaining bubbles, on the order of 1/8 - 3/8 inches in diameter, are formed as the gas stream rises, which bubbles impact against the horizontal baffle. The high velocity gases impart sufficient kinetic energy to the system to enable the necessary chemical reactions and scrubbing to proceed.

  10. A novel method for furfural recovery via gas stripping assisted vapor permeation by a polydimethylsiloxane membrane

    NASA Astrophysics Data System (ADS)

    Hu, Song; Guan, Yu; Cai, Di; Li, Shufeng; Qin, Peiyong; Karim, M. Nazmul; Tan, Tianwei

    2015-03-01

    Furfural is an important platform chemical with a wide range of applications. However, due to the low concentration of furfural in the hydrolysate, the conventional methods for furfural recovery are energy-intensive and environmentally unfriendly. Considering the disadvantages of pervaporation (PV) and distillation in furfural separation, a novel energy-efficient `green technique', gas stripping assisted vapor permeation (GSVP), was introduced in this work. In this process, the polydimethylsiloxane (PDMS) membrane was prepared by employing water as solvent. Coking in pipe and membrane fouling was virtually non-existent in this new process. In addition, GSVP was found to achieve the highest pervaporation separation index of 216200 (permeate concentration of 71.1 wt% and furfural flux of 4.09 kgm-2h-1) so far, which was approximately 2.5 times higher than that found in pervaporation at 95°C for recovering 6.0 wt% furfural from water. Moreover, the evaporation energy required for GSVP decreased by 35% to 44% relative to that of PV process. Finally, GSVP also displayed more promising potential in industrial application than PV, especially when coupled with the hydrolysis process or fermentation in biorefinery industry.

  11. Standard test method for water in lint cotton by oven evaporation combined with volumetric Karl Fischer Titration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The referenced test method for total water content and water regain in lint cotton was developed by USDA scientists in New Orleans at the request of the cotton industry. The method covers the determination of the total water (free and bound) in raw and lint cotton at moisture equilibrium from con...

  12. EVALUATION OF METHODS USED TO DESORB THE CONSTITUENTS ADSORBED ON THE CHARCOAL CONTAINED IN AUTOMOTIVE EVAPORATIVE CANISTERS--PART II

    EPA Science Inventory

    This report presents the conclusion of a two-part study with evaluated current extraction methods for anaylizing in automobiles. The second part of this study investigated the use of solvent-free extraction methods such as high pressure C02 soxhlet extraction and vacuum transfer ...

  13. EVALUATION OF METHODS USED TO DESORB THE CONSTITUENTS ADSORBED ON THE CHARCOAL CONTAINED IN AUTOMOTIVE EVAPORATIVE CANISTERS

    EPA Science Inventory

    This report presents the conclusion of a two-part study with evaluated current extraction methods for anaylizing in automobiles. The second part of this study investigated the use of solvent-free extraction methods such as high pressure C02 soxhlet extraction and vacuum transfer ...

  14. A new method to continuously monitor trace gas flux

    NASA Astrophysics Data System (ADS)

    Nickerson, N.; Risk, D.; McArthur, G.; Beltrami, H.

    2009-04-01

    Here we present a new method by which the flux of a gas or gases can be measured and monitored continuously. The method relies on a passive diffusion probe and a mathematical flux approximation originally developed for heat flow research. The probe is simple, rugged and has no moving parts making it ideal for winter use or for deployment at infrequently serviced field sites. The reliability of the method has been proven through model simulations, experimental and field trials and careful comparison with industry standard LiCOR chambers. In this poster we present data showing 1) probe benchmark tests in the lab, 2) continuous fluxes in simulated summer conditions, 3) overwinter fluxes at a frost-prone bare soil sites and 4) overwinter fluxes under a deep snowpack. Ideally, this measurement system will provide an inexpensive and reliable method by which soil fluxes can be continuously monitored, especially under harsh winter conditions that present significant challenges for current technologies.

  15. Usability of calcium carbide gas pressure method in hydrological sciences

    NASA Astrophysics Data System (ADS)

    Arsoy, S.; Ozgur, M.; Keskin, E.; Yilmaz, C.

    2013-10-01

    Soil moisture is a key engineering variable with major influence on ecological and hydrological processes as well as in climate, weather, agricultural, civil and geotechnical applications. Methods for quantification of the soil moisture are classified into three main groups: (i) measurement with remote sensing, (ii) estimation via (soil water balance) simulation models, and (iii) measurement in the field (ground based). Remote sensing and simulation modeling require rapid ground truthing with one of the ground based methods. Calcium carbide gas pressure (CCGP) method is a rapid measurement procedure for obtaining soil moisture and relies on the chemical reaction of the calcium carbide reagent with the water in soil pores. However, the method is overlooked in hydrological science applications. Therefore, the purpose of this study is to evaluate the usability of the CCGP method in comparison with standard oven-drying and dielectric methods in terms of accuracy, time efficiency, operational ease, cost effectiveness and safety for quantification of the soil moisture over a wide range of soil types. The research involved over 250 tests that were carried out on 15 different soil types. It was found that the accuracy of the method is mostly within ±1% of soil moisture deviation range in comparison to oven-drying, and that CCGP method has significant advantages over dielectric methods in terms of accuracy, cost, operational ease and time efficiency for the purpose of ground truthing.

  16. The growth of benzophenone crystals by Sankaranarayanan-Ramasamy (SR) method and slow evaporation solution technique (SEST): A comparative investigation

    SciTech Connect

    Senthil Pandian, M.; Boopathi, K. [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110, Tamilnadu (India)] [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110, Tamilnadu (India); Ramasamy, P., E-mail: ramasamyp@ssn.edu.in [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110, Tamilnadu (India); Bhagavannarayana, G. [Materials Characterization Division, National Physical Laboratory, New Delhi 110 012 (India)] [Materials Characterization Division, National Physical Laboratory, New Delhi 110 012 (India)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Benzophenone single crystal was grown by Sankaranarayanan-Ramasamy method which has the sizes of 1060 mm length and 55 mm diameter for the first time. Black-Right-Pointing-Pointer The conventional and SR-grown benzophenone crystals were characterized and compared using HRXRD, etching, laser damage threshold, microhardness, UV-transmittance, birefringence and dielectric analysis. Black-Right-Pointing-Pointer The SR-grown benzophenone crystal has higher LDT, microhardness, transparency, dielectric permittivity, birefringence and lower FWHM, EPD, dielectric loss than the crystal grown by conventional method. Black-Right-Pointing-Pointer The probable reason for higher crystalline perfection in SR-grown crystal was discussed. -- Abstract: Longest unidirectional Left-Pointing-Angle-Bracket 1 0 0 Right-Pointing-Angle-Bracket benzophenone (BP) crystal having dimension of 1060 mm length and 55 mm diameter was grown by Sankaranarayanan-Ramasamy method. The growth rate was measured by monitoring the elevation of the crystal-solution interface at different temperatures. The high resolution X-ray diffraction and etching measurements indicate that the unidirectional grown benzophenone crystal has good crystalline perfection and less density of defects. The optical damage threshold of SEST and SR grown BP crystals has been investigated and found that the SR grown benzophenone crystal has higher laser damage threshold value than the conventional method grown crystal. Microhardness measurement shows that crystals grown by SR method have a higher mechanical stability than the crystals grown by SEST method. Dielectric permittivity and birefringence are high in SR grown crystal compared to SEST grown BP crystal. The UV-vis-NIR results show that SR method grown crystal exhibits 7% higher transmittance as against crystals grown by conventional method.

  17. Exhaust gas purifying method and apparatus for internal combustion engines

    SciTech Connect

    Fujitani, Y.; Muraki, H.; Yokota, K.; Sobukawa, H.; Matsunaga, S.

    1986-10-21

    An exhaust gas purifying method is described for an internal combustion engine comprising: detecting the temperature of an exhaust gas purifying catalyst disposed in an exhaust system of the internal combustion engine by a temperature sensor; converting a signal from the temperature sensor to a first electric signal by a signal converter; oscillating a second electric having a frequency and an amplitude and a predetermined frequency and amplitude range. The predetermined frequency and amplitude range are predetermined based upon the kind of the catalyst used. The frequency and amplitude of the second signal are adjusted within the predetermined range by an oscillator in accordance with the first electric signal from the signal converter; and varying an actual air-fuel ratio toward the higher air-fuel ratio side and the lower air-fuel ratio side with respect to the theoretical air-fuel ratio, based on the second electric signal from the oscillator.

  18. Self-contained cryogenic gas sampling apparatus and method

    DOEpatents

    McManus, Gary J. (Idaho Falls, ID); Motes, Billy G. (Idaho Falls, ID); Bird, Susan K. (Idaho Falls, ID); Kotter, Dale K. (Shelley, ID)

    1996-01-01

    Apparatus for obtaining a whole gas sample, composed of: a sample vessel having an inlet for receiving a gas sample; a controllable valve mounted for controllably opening and closing the inlet; a valve control coupled to the valve for opening and closing the valve at selected times; a portable power source connected for supplying operating power to the valve control; and a cryogenic coolant in thermal communication with the vessel for cooling the interior of the vessel to cryogenic temperatures. A method of obtaining an air sample using the apparatus described above, by: placing the apparatus at a location at which the sample is to be obtained; operating the valve control to open the valve at a selected time and close the valve at a selected subsequent time; and between the selected times maintaining the vessel at a cryogenic temperature by heat exchange with the coolant.

  19. Self-contained cryogenic gas sampling apparatus and method

    DOEpatents

    McManus, G.J.; Motes, B.G.; Bird, S.K.; Kotter, D.K.

    1996-03-26

    Apparatus for obtaining a whole gas sample, is composed of: a sample vessel having an inlet for receiving a gas sample; a controllable valve mounted for controllably opening and closing the inlet; a valve control coupled to the valve for opening and closing the valve at selected times; a portable power source connected for supplying operating power to the valve control; and a cryogenic coolant in thermal communication with the vessel for cooling the interior of the vessel to cryogenic temperatures. A method is described for obtaining an air sample using the apparatus described above, by: placing the apparatus at a location at which the sample is to be obtained; operating the valve control to open the valve at a selected time and close the valve at a selected subsequent time; and between the selected times maintaining the vessel at a cryogenic temperature by heat exchange with the coolant. 3 figs.

  20. Development of NDE methods for hot gas filters.

    SciTech Connect

    Deemer, C.; Ellingson, W. A.; Koehl, E. R.; Lee, H.; Spohnholtz, T.; Sun, J. G.

    1999-07-21

    Ceramic hot gas candle filters are currently under development for hot gas particulate cleanup in advanced coal-based power systems. The ceramic materials for these filters include nonoxide monolithic, nonoxide-fiber-reinforced composites, and nonoxide reticulated foam. A concern is the lack of reliable data on which to base decisions for reusing or replacing hot gas filters during plant shutdowns. The work in this project is aimed at developing nondestructive evaluation (FIDE) technology to allow detection, and determination of extent, of life-limiting characteristics such as thermal fatigue, oxidation, damage from ash bridging such as localized cracking, damage from local burning, and elongation at elevated temperature. Although in-situ NDE methods are desirable in order to avoid disassembly of the candle filter vessels, the current vessel designs, the presence of filter cakes and possible ash bridging, and the state of NDE technology prevent this. Candle filter producers use a variety of NDE methods to ensure as-produced quality. While impact acoustic resonance offers initial promise for examining new as-produced filters and for detecting damage in some monolithic filters when removed from service, it presents difficulties in data interpretation, it lacks localization capability, and its applicability to composites has yet to be demonstrated. Additional NDE technologies being developed and evaluated in this program and whose applicability to both monolithics and composites has been demonstrated include (a) full-scale thermal imaging for analyzing thermal property variations; (b) fret, high-spatial-resolution X-ray imaging for detecting density variations and dimensional changes; (c) air-coupled ultrasonic methods for determining through-thickness compositional variations; and (d) acoustic emission technology with mechanical loading for detecting localized bulk damage. New and exposed clay-bonded SiC filters and CVI-SiC composite filters have been tested with these additional NDE methods.

  1. Evaporation from flowing channels

    SciTech Connect

    Fulford, J.M.; Sturm, T.W.

    1984-03-01

    Stability-dependent and Dalton-type mass transfer formulas are determined from experimental evaporation data in ambient and heated channels and are shown to have similar performance in prediction of evaporation. The formulas developed are compared with those proposed by other investigators for lakes and flowing channels. The evaporation data were obtained from a heat-budget analysis of two large outdoor channels, one of which received ambient-temperature water from an adjacent reservoir while the other received an artificially-heated discharge. Daily evaporation was calculated from bihourly values of water temperature and hourly values of meteorological variables for a 63-day study period in the summer. The evaporation data were then used to derive mass transfer evaporation formulas for heated and ambient flowing channels.

  2. An evaluation of models of bare soil evaporation formulated with different land surface boundary conditions and assumptions

    NASA Astrophysics Data System (ADS)

    Smits, Kathleen M.; Ngo, Viet V.; Cihan, Abdullah; Sakaki, Toshihiro; Illangasekare, Tissa H.

    2012-12-01

    Bare soil evaporation is a key process for water exchange between the land and the atmosphere and an important component of the water balance. However, there is no agreement on the best modeling methodology to determine evaporation under different atmospheric boundary conditions. Also, there is a lack of directly measured soil evaporation data for model validation to compare these methods to establish the validity of their mathematical formulations. Thus, a need exists to systematically compare evaporation estimates using existing methods to experimental observations. The goal of this work is to test different conceptual and mathematical formulations that are used to estimate evaporation from bare soils to critically investigate various formulations and surface boundary conditions. Such a comparison required the development of a numerical model that has the ability to incorporate these boundary conditions. For this model, we modified a previously developed theory that allows nonequilibrium liquid/gas phase change with gas phase vapor diffusion to better account for dry soil conditions. Precision data under well-controlled transient heat and wind boundary conditions were generated, and results from numerical simulations were compared with experimental data. Results demonstrate that the approaches based on different boundary conditions varied in their ability to capture different stages of evaporation. All approaches have benefits and limitations, and no one approach can be deemed most appropriate for every scenario. Comparisons of different formulations of the surface boundary condition validate the need for further research on heat and vapor transport processes in soil for better modeling accuracy.

  3. Investigation of two-fluid methods for Large Eddy Simulation of spray combustion in Gas Turbines

    E-print Network

    Investigation of two-fluid methods for Large Eddy Simulation of spray combustion in Gas Turbines the EL method well suited for gas turbine computations, but RANS with the EE approach may also be found

  4. Laboratory prototype flash evaporator

    NASA Technical Reports Server (NTRS)

    Gaddis, J. L.

    1972-01-01

    A laboratory prototype flash evaporator that is being developed as a candidate for the space shuttle environmental control system expendable heat sink is described. The single evaporator configuration uses water as an evaporant to accommodate reentry and on-orbit peak heat loads, and Freon 22 for terrestrial flight phases below 120,000 feet altitude. The design features, fabrication techniques used for the prototype unit, redundancy considerations, and the fluid temperature control arrangement are reported in detail. The results of an extensive test program to determine the evaporator operational characteristics under a wide variety of conditions are presented.

  5. Structure and mechanism of the formation of core–shell nanoparticles obtained through a one-step gas-phase synthesis by electron beam evaporation

    PubMed Central

    Bardakhanov, Sergey P; Schreiber, Makoto; Bazarova, Dashima G; Romanov, Nikolai A; Baldanov, Boris B; Radnaev, Bair R; Syzrantsev, Viacheslav V

    2015-01-01

    Summary The structure of core–shell Cu@silica and Ag@Si nanoparticles obtained in one-step through evaporation of elemental precursors by a high-powered electron beam are investigated. The structure of the core and shell of the particles are investigated in order to elucidate their mechanisms of formation and factors affecting the synthesis. It is proposed that the formation of Cu@silica particles is mainly driven by surface tension differences between Cu and Si while the formation of Ag@Si particles is mainly driven by differences in the vapour concentration of the two components. PMID:25977857

  6. Analysis of a resistance-energy balance method for estimating daily evaporation from wheat plots using one-time-of-day infrared temperature observations

    NASA Technical Reports Server (NTRS)

    Choudhury, B. J.; Idso, S. B.; Reginato, R. J.

    1986-01-01

    Accurate estimates of evaporation over field-scale or larger areas are needed in hydrologic studies, irrigation scheduling, and meteorology. Remotely sensed surface temperature might be used in a model to calculate evaporation. A resistance-energy balance model, which combines an energy balance equation, the Penman-Monteith (1981) evaporation equation, and van den Honert's (1948) equation for water extraction by plant roots, is analyzed for estimating daily evaporation from wheat using postnoon canopy temperature measurements. Additional data requirements are half-hourly averages of solar radiation, air and dew point temperatures, and wind speed, along with reasonable estimates of canopy emissivity, albedo, height, and leaf area index. Evaporation fluxes were measured in the field by precision weighing lysimeters for well-watered and water-stressed wheat. Errors in computed daily evaporation were generally less than 10 percent, while errors in cumulative evaporation for 10 clear sky days were less than 5 percent for both well-watered and water-stressed wheat. Some results from sensitivity analysis of the model are also given.

  7. Method and apparatus for dispensing compressed natural gas and liquified natural gas to natural gas powered vehicles

    DOEpatents

    Bingham, Dennis A.; Clark, Michael L.; Wilding, Bruce M.; Palmer, Gary L.

    2005-05-31

    A fueling facility and method for dispensing liquid natural gas (LNG), compressed natural gas (CNG) or both on-demand. The fueling facility may include a source of LNG, such as cryogenic storage vessel. A low volume high pressure pump is coupled to the source of LNG to produce a stream of pressurized LNG. The stream of pressurized LNG may be selectively directed through an LNG flow path or to a CNG flow path which includes a vaporizer configured to produce CNG from the pressurized LNG. A portion of the CNG may be drawn from the CNG flow path and introduced into the CNG flow path to control the temperature of LNG flowing therethrough. Similarly, a portion of the LNG may be drawn from the LNG flow path and introduced into the CNG flow path to control the temperature of CNG flowing therethrough.

  8. Laser evaporation of models of normal and tumoral biological tissues

    NASA Astrophysics Data System (ADS)

    Ulyanov, V. A.; Dmitriev, A. K.; Konovalov, A. N.; Kortunov, V. N.; Reshetov, I. V.; Matorin, O. V.

    2012-02-01

    The results of laser evaporation of models of healthy and tumoral biological tissues are presented. The diagnostics of laser evaporation of such models by autodyne method was realized. It is shown the level of autodyne signal varies in different degrees depending on the type of healthy and tumoral biotissues at its laser evaporation.

  9. Laser evaporation of models of normal and tumoral biological tissues

    NASA Astrophysics Data System (ADS)

    Ulyanov, V. A.; Dmitriev, A. K.; Konovalov, A. N.; Kortunov, V. N.; Reshetov, I. V.; Matorin, O. V.

    2011-09-01

    The results of laser evaporation of models of healthy and tumoral biological tissues are presented. The diagnostics of laser evaporation of such models by autodyne method was realized. It is shown the level of autodyne signal varies in different degrees depending on the type of healthy and tumoral biotissues at its laser evaporation.

  10. Rapid Evaporation of microbubbles

    NASA Astrophysics Data System (ADS)

    Gautam, Jitendra; Esmaeeli, Asghar

    2008-11-01

    When a liquid is heated to a temperature far above its boiling point, it evaporates abruptly. Boiling of liquid at high temperatures can be explosive and destructive, and poses a potential hazard for a host of industrial processes. Explosive boiling may occur if a cold and volatile liquid is brought into contact with a hot and non-volatile liquid, or if a liquid is superheated or depressurized rapidly. Such possibilities are realized, for example, in the depressurization of low boiling point liquefied natural gas (LNG) in the pipelines or storage tanks as a result of a leak. While boiling of highly heated liquids can be destructive at macroscale, the (nearly) instantaneous pace of the process and the release of large amount of kinetic energy make the phenomena extremely attractive at microscale where it is possible to utilize the released energy to derive micromechanical systems. For instance, there is currently a growing interest in micro-explosion of liquid for generation of micro bubbles for actuation purposes. The aim of the current study is to gain a fundamental understanding of the subject using direct numerical simulations. In particular, we seek to investigate the boundary between stable and unstable nucleus growth in terms of the degree of liquid superheat and to compare the dynamics of unstable and stable growth.

  11. Operating method for gas turbine with variable inlet vanes

    SciTech Connect

    Morishita, Susumu; Miyake, Yoshiyaki; Uchida, Seishi.

    1993-07-06

    A method is described of operating a gas turbine engine having a centrifugal compressor which is driven by a high-pressure turbine, and wherein the centrifugal compressor is the only compressor of the engine, comprising the steps of: positioning a variable inlet guide vane at an inlet air passage of the centrifugal compressor for adjusting the air flow rate through the engine; and changing the orientation of the guide vane while keeping the speed of rotation of the engine at a high level near its rated value to control the output of the engine by controlling the air flow rate through the engine.

  12. Methods of calculating engineering parameters for gas separations

    NASA Technical Reports Server (NTRS)

    Lawson, D. D.

    1980-01-01

    A group additivity method has been generated which makes it possible to estimate, from the structural formulas alone, the energy of vaporization and the molar volume at 25 C of many nonpolar organic liquids. From these two parameters and appropriate thermodynamic relationships it is then possible to predict the vapor pressure of the liquid phase and the solubility of various gases in nonpolar organic liquids. The data are then used to evaluate organic and some inorganic liquids for use in gas separation stages or as heat exchange fluids in prospective thermochemical cycles for hydrogen production.

  13. Method For Enhanced Gas Monitoring In High Density Flow Streams

    DOEpatents

    Von Drasek, William A. (Oak Forest, IL); Mulderink, Kenneth A. (Countryside, IL); Marin, Ovidiu (Lisle, IL)

    2005-09-13

    A method for conducting laser absorption measurements in high temperature process streams having high levels of particulate matter is disclosed. An impinger is positioned substantially parallel to a laser beam propagation path and at upstream position relative to the laser beam. Beam shielding pipes shield the beam from the surrounding environment. Measurement is conducted only in the gap between the two shielding pipes where the beam propagates through the process gas. The impinger facilitates reduced particle presence in the measurement beam, resulting in improved SNR (signal-to-noise) and improved sensitivity and dynamic range of the measurement.

  14. Waste tank ventilation rates measured with a tracer gas method

    SciTech Connect

    Huckaby, J.L.; Evans, J.C.; Sklarew, D.S.; Mitroshkov, A.V.

    1998-08-01

    Passive ventilation with the atmosphere is used to prevent accumulation of waste gases and vapors in the headspaces of 132 of the 177 high-level radioactive waste Tanks at the Hanford Site in Southeastern Washington State. Measurements of the passive ventilation rates are needed for the resolution of two key safety issues associated with the rates of flammable gas production and accumulation and the rates at which organic salt-nitrate salt mixtures dry out. Direct measurement of passive ventilation rates using mass flow meters is not feasible because ventilation occurs va multiple pathways to the atmosphere (i.e., via the filtered breather riser and unsealed tank risers and pits), as well as via underground connections to other tanks, junction boxes, and inactive ventilation systems. The tracer gas method discussed in this report provides a direct measurement of the rate at which gases are removed by ventilation and an indirect measurement of the ventilation rate. The tracer gas behaves as a surrogate of the waste-generated gases, but it is only diminished via ventilation, whereas the waste gases are continuously released by the waste and may be subject to depletion mechanisms other than ventilation. The fiscal year 1998 tracer studies provide new evidence that significant exchange of air occurs between tanks via the underground cascade pipes. Most of the single-shell waste tanks are connected via 7.6-cm diameter cascade pipes to one or two adjacent tanks. Tracer gas studies of the Tank U-102/U-103 system indicated that the ventilation occurring via the cascade line could be a significant fraction of the total ventilation. In this two-tank cascade, air evidently flowed from Tank U-103 to Tank U-102 for a time and then was observed to flow from Tank U-102 to Tank U-103.

  15. A novel method for rapid determination of total solid content in viscous liquids by multiple headspace extraction gas chromatography.

    PubMed

    Xin, Li-Ping; Chai, Xin-Sheng; Hu, Hui-Chao; Barnes, Donald G

    2014-09-01

    This work demonstrates a novel method for rapid determination of total solid content in viscous liquid (polymer-enriched) samples. The method is based multiple headspace extraction gas chromatography (MHE-GC) on a headspace vial at a temperature above boiling point of water. Thus, the trend of water loss from the tested liquid due to evaporation can be followed. With the limited MHE-GC testing (e.g., 5 extractions) and a one-point calibration procedure (i.e., recording the weight difference before and after analysis), the total amount of water in the sample can be determined, from which the total solid contents in the liquid can be calculated. A number of black liquors were analyzed by the new method which yielded results that closely matched those of the reference method; i.e., the results of these two methods differed by no more than 2.3%. Compared with the reference method, the MHE-GC method is much simpler and more practical. Therefore, it is suitable for the rapid determination of the solid content in many polymer-containing liquid samples. PMID:25064534

  16. Optical methods for monitoring harmful gas in animal facilities

    NASA Astrophysics Data System (ADS)

    Zhang, Shirui; Dong, Daming; Zheng, Wengang; Wang, Jihua

    2014-06-01

    Animal facilities produce large amounts of harmful gases such as ammonia, hydrogen sulfide, and methane, many of which have a pungent odor. The harmful gases produced by animal housing not only affect the health of people and livestock but also pollute the air. The detection of the harmful gases can effectively improve efficiency of livestock production and reduce environmental pollution. More and more optical detection methods are applied to the detection of the harmful gases produced by animal housing. This summarizes optical detection methods for monitoring the harmful gases in animal housing recently, including nondispersive infrared gas analyzer, ultraviolet differential optical absorption spectroscopy, Fourier transform infrared spectroscopy, and tunable diode laser absorption spectroscopy. The basic principle and the characteristics of these methods are illustrated and the applications on the detection of harmful gases in animal housing are described. Meanwhile, the research of harmful gases monitoring for livestock production based on these methods were listed. The current situation and future development of the detection methods for harmful gases generated by animal housing were summarized by comparing the advantages and disadvantages of each method.

  17. Bulk growth of ninhydrin single crystals by solvent evaporation method and its characterization for SHG and THG applications.

    PubMed

    Vijayan, N; Philip, J; Haranath, D; Rathi, Brijesh; Bhagavannarayana, G; Halder, S K; Roy, N; Jayalakshmy, M S; Verma, Sunil

    2014-03-25

    Ninhydrin is a well-known compound generally used in amino acid synthesis and also for detecting the latent fingerprints on porous surfaces. Single crystals can be grown by dissolving the compound in double distilled water at ambient temperature, and can be used as a potential material for second and third harmonic generation applications. The grown specimen was subjected to different characterization techniques in order to find out its suitability for device fabrication. Its lattice dimensions have been confirmed by X-ray powder diffraction and its crystalline quality has been assessed by high resolution X-ray diffraction and X-ray topography methods. The presence of functional groups was identified from HETCOR analysis and confirmed the absence of impurities during crystallization. Its optical properties have been examined by photoluminescence and birefringence analyses. Its thermal parameters such as thermal diffusivity, thermal conductivity and specific capacity have been carried out by following photopyroelectric method. Third order nonlinear optical measurements have been carried out using Z-scan technique and its nonlinear optical absorption coefficient has been determined. PMID:24317258

  18. Evaporation, Boiling and Bubbles

    ERIC Educational Resources Information Center

    Goodwin, Alan

    2012-01-01

    Evaporation and boiling are both terms applied to the change of a liquid to the vapour/gaseous state. This article argues that it is the formation of bubbles of vapour within the liquid that most clearly differentiates boiling from evaporation although only a minority of chemistry textbooks seems to mention bubble formation in this context. The…

  19. Modelling evaporation from reservoirs

    Microsoft Academic Search

    B. HENDERSON-SELLERS

    It is shown that a numerical model for predicting the depth time variation of water temperature in a fresh water lake or reservoir can be used also for prediction of water losses due to evaporation. The seasonal change in peak evaporation from summer (in small lakes) to winter (in large lakes) is satisfactorily simulated.

  20. Evaporative Cooling Membrane Device

    NASA Technical Reports Server (NTRS)

    Lomax, Curtis (Inventor); Moskito, John (Inventor)

    1999-01-01

    An evaporative cooling membrane device is disclosed having a flat or pleated plate housing with an enclosed bottom and an exposed top that is covered with at least one sheet of hydrophobic porous material having a thin thickness so as to serve as a membrane. The hydrophobic porous material has pores with predetermined dimensions so as to resist any fluid in its liquid state from passing therethrough but to allow passage of the fluid in its vapor state, thereby, causing the evaporation of the fluid and the cooling of the remaining fluid. The fluid has a predetermined flow rate. The evaporative cooling membrane device has a channel which is sized in cooperation with the predetermined flow rate of the fluid so as to produce laminar flow therein. The evaporative cooling membrane device provides for the convenient control of the evaporation rates of the circulating fluid by adjusting the flow rates of the laminar flowing fluid.

  1. Gas leak location method for pressurized cable networks using pattern matching of transient pressure drop characteristics

    Microsoft Academic Search

    Kazutoki Takeda

    1994-01-01

    Gas pressurization systems are widely used in telecommunication cable networks. These systems maintain the gas pressure in the cable at a higher level than the environmental pressure thus preventing water or moisture from penetrating the cable. This paper proposes a new gas leak location method which employs the pattern matching of transient characteristics while the gas pressure drops

  2. Improvement in Thermal-Ionization Mass Spectrometry (TIMS) using Total Flash Evaporation (TFE) method for lanthanides isotope ratio measurements in transmutation targets

    SciTech Connect

    Mialle, S.; Gourgiotis, A.; Aubert, M.; Stadelmann, G.; Gautier, C.; Isnard, H. [Commissariat a l'Energie Atomique, CEA Saclay, DEN/DPC/SECR/LANIE, 91191 Gif sur Yvette (France); Chartier, F. [Commissariat a l'Energie Atomique, CEA Saclay, DEN/DPC, 91191 Gif sur Yvette (France)

    2011-07-01

    The experiments involved in the PHENIX french nuclear reactor to obtain precise and accurate data on the total capture cross sections of the heavy isotopes and fission products require isotopic ratios measurements with uncertainty of a few per mil. These accurate isotopic ratio measurements are performed with mass spectrometer equipped with multi-collector system. The major difficulty for the analyses of these actinides and fission products is the low quantity of the initial powder enclosed in steel container (3 to 5 mg) and the very low quantities of products formed (several {mu}g) after irradiation. Specific analytical developments are performed by Thermal Ionization Mass Spectrometry (TIMS) to be able to analyse several nanograms of elements with this technique. A specific method of acquisition named Total Flash Evaporation was adapted in this study in the case of lanthanide measurements for quantity deposited on the filament in the order of 2 ng and applied on irradiated fuel. To validate the analytical approach and discuss about the accuracy of the data, the isotopic ratios obtained by TIMS are compared with other mass spectrometric techniques such as Multiple-Collector Inductively Coupled Plasma Mass Spectrometer (MC-ICPMS). (authors)

  3. Growth and green defect emission of ZnPbO nanorods by a catalyst-assisted thermal evaporation-oxidation method

    NASA Astrophysics Data System (ADS)

    Tsega, Moges; Kuo, Dong-Hau; Dejene, F. B.

    2015-04-01

    Vertically aligned undoped and Pb-doped ZnO (ZnPbO) nanorods have been successfully synthesized by a thermal evaporation-oxidation method with the Fe-based catalysts on sapphire substrate at different temperatures (600-700 °C) for 2 h. Effects of growth temperature and Pb-doping on the morphology, structure, and optical properties of as deposited nanorods have been investigated. The products at 600-700 °C showed a 1D nanorod morphology with an average diameter in the range 450-150 nm, and length in the range 3-6 ?m. Well-aligned, uniform and elongated nanorods were obtained at 700 °C. The photoluminescence (PL) spectra showed that undoped ZnO nanorods exhibited a strong and sharp ultraviolet (UV) band edge emission peak at 380 nm (3.26 eV), whereas Pb-doped ZnO nanorod arrays exhibited a relative weak ultraviolet (UV) emission at 380 nm and a strong green emission at 515 nm (2.41 eV). A mechanism for the nanorod growth and defect emission is proposed.

  4. The two options for sample evaporation in hot GC injectors: thermospray and band formation. optimization of conditions and injector design.

    PubMed

    Grob, Koni; Biedermann, Maurus

    2002-01-01

    Although classical split and splitless injection is more than 30 years old, we only start to understand the vaporization process in the injector. Solvent evaporation determines much of the process and is the first obstacle to overcome. Videos recorded on devices imitating injectors showed that sample (solvent) evaporation is often a violent process which is poorly controlled and might well explain many of the puzzling quantitative results often obtained. We do not adequately take into account that two vaporization techniques are in use. Partial solvent evaporation inside the syringe needle (optimized as "hot needle injection") produces thermospray: the sample liquid is nebulized upon leaving the needle. The resulting fog is rapidly slowed and moves with the gas. Solute evaporation largely occurs from microparticles suspended in the gas phase. Empty liners are most suitable. Fast autosamplers suppress vaporization in the needle, i.e., nebulization, and shoot a band of liquid into the chamber that must be stopped by a packing or obstacles suitable to hold the liquid in place during the 0.2-5 s required for solvent evaporation. Solute evaporation largely occurs from the surfaces onto which the sample is deposited. Insights into these mechanisms help optimize conditions in a more rational manner. Methods should specify whether they were optimized and validated for injection with thermospray or band formation. The insights should also enable a significant improvement of the injector design, particularly for splitless injection. PMID:11795775

  5. A New Technique Keeping off the Mn Evaporant from Oxygen Atmosphere during Reactive Evaporation Process

    Microsoft Academic Search

    Masaaki Isai; Takeyoshi Shimada; Takaaki Matsui; Hiroshi Fujiyasu

    2001-01-01

    Manganese oxide films for lithium secondary batteries were prepared using a reactive evaporation method. The Mn metal in the crucible suffers severe oxidation during the reactive evaporation process, which deteriorates it's deposition rate with increasing deposition run. It is also difficult to maintain the stoichiometry of films from run to run. This paper shows a new technique which keeps off

  6. Effects of the surroundings and conformerisation of n-dodecane molecules on evaporation/condensation processes.

    PubMed

    Gun'ko, Vladimir M; Nasiri, Rasoul; Sazhin, Sergei S

    2015-01-21

    The evaporation/condensation coefficient (?) and the evaporation rate (?) for n-dodecane vs. temperature, gas pressure, gas and liquid density, and solvation effects at a droplet surface are analysed using quantum chemical density functional theory calculations of several ensembles of conformers of n-dodecane molecules in the gas phase (hybrid functional ?B97X-D with the cc-pVTZ and cc-pVDZ basis sets) and in liquid phase (solvation method: SMD/?B97X-D). It is shown that ? depends more strongly on a number of neighbouring molecules interacting with an evaporating molecule at a droplet surface (this number is estimated through changes in the surface Gibbs free energy of solvation) than on pressure in the gas phase or conformerisation and cross-conformerisation of molecules in both phases. Thus, temperature and the surrounding effects at droplet surfaces are the dominant factors affecting the values of ? for n-dodecane molecules. These values are shown to be similar (at reduced temperatures T/Tc < 0.8) or slightly larger (at T/Tc > 0.8) than the values of ? calculated by the molecular dynamics force fields (MD FF) methods. This endorses the reliability of the previously developed classical approach to estimation of ? by the MD FF methods, except at temperatures close to the critical temperature. PMID:25612715

  7. Evaporative Cooling of Trapped Atoms

    Microsoft Academic Search

    Wolfgang Ketterle; N. J. Van Druten

    1996-01-01

    This report discusses the following topics on evaporative cooling of trapped atoms: Theoretical models for evaporative cooling; the role of collisions for real atoms; experimental techniques and summary of evaporative cooling experiments. 166 refs., 6 figs., 3 tabs.

  8. Gas chromatographic method for determination of uracil herbicides in roots of Echinacea angustifolia Moench (Asteraceae)

    Microsoft Academic Search

    Štefánia Vaverková

    1998-01-01

    A GC\\/NPD method and a rapid screening TLC method were developed for the simultaneous determination of uracil herbicide residues (bromacil, lenacil, terbacil) in the roots of Echinacea angustifolia Moench (Asteraceae). The uracil herbicide residues were extracted into acetone. After evaporation of acetone from the acetone-water extract the residue was dissolved in water-methanol (5:1 v\\/v). Cyclohexane was used for removal of

  9. Groundwater changes in evaporating basins using gypsum crystals' isotopic compositions

    NASA Astrophysics Data System (ADS)

    Gatti, E.; Bustos, D.; Allwood, A.; Coleman, M. L.

    2014-12-01

    While the dynamics of groundwater evaporation are well known, it is still challenging to reconstruct the water patterns in areas where water is not available anymore. We selected a specific location in White Sands National Monument (WSNM), New Mexico, to validate a method to extract information from hydrated minerals regarding past groundwater evaporation patterns in evaporitic basins. WSNM has gypsum (CaSO4.2H2O) dunes and crystals precipitated from the evaporation of an ancient lake. Our approach aims to extract the water of crystallization of gypsum and measure its oxygen and hydrogen isotopic compositions, in order to reconstruct the groundwater history of the area. The idea is that as the mother brine evaporates its isotopic composition changes continuously, recorded as water of crystallization in successive growth zones of gypsum. To check if the isotopic composition of the salt could effectively differentiate between distinctive humidity conditions, the methodology was tested first on synthetic gypsum grown under controlled humidity and temperature conditions. T and RH% were maintained constant in a glove box and precipitated gypsum was harvested every 24 hours. d2H and d18O of water of crystallization from the synthetic gypsum was extracted using a specially developed technique on a TC/EA. The brine was measured using a Gas Bench II for d18O and an H-Device for d2H on a Thermo Finnigan MAT 253 mass spectrometer. With the method tested, we measured natural gypsum. In order to identify the growth zones we mapped the surface of the crystals using an experimental space flight XRF instrument. Crystals were then sampled for isotopic analyses. Preliminary results suggest that site-specific groundwater changes can be described by the isotopic variations. We will show that the methodology is a reliable and fast method to quantify hydrological changes in a targeted environment. The study is currently ongoing but the full dataset will be presented at the conference.

  10. Chromatographic method of determining the components of the return coke oven gas

    Microsoft Academic Search

    V. I. Pakhomov; N. N. Gavrilov; V. I. Aleshin; I. Ya. Efremkov

    1982-01-01

    In plant laboratories, the composition of the return coke oven gas is usually determined by means of a VTI-2 gas analyzer. The analysis method is laborious and prolonged and the error of determination of the content of certain components reaches 15 relative percent. In order to solve these problems, a method of analyzing the oven gas was developed using a

  11. Sheet Membrane Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Bue, Grant; Trevino, Luis; Zapata, Felipe; Dillion, Paul; Castillo, Juan; Vonau, Walter; Wilkes, Robert; Vogel, Matthew; Frodge, Curtis

    2013-01-01

    A document describes a sheet membrane spacesuit water membrane evaporator (SWME), which allows for the use of one common water tank that can supply cooling water to the astronaut and to the evaporator. Test data showed that heat rejection performance dropped only 6 percent after being subjected to highly contaminated water. It also exhibited robustness with respect to freezing and Martian atmospheric simulation testing. Water was allowed to freeze in the water channels during testing that simulated a water loop failure and vapor backpressure valve failure. Upon closing the backpressure valve and energizing the pump, the ice eventually thawed and water began to flow with no apparent damage to the sheet membrane. The membrane evaporator also serves to de-gas the water loop from entrained gases, thereby eliminating the need for special degassing equipment such as is needed by the current spacesuit system. As water flows through the three annular water channels, water evaporates with the vapor flowing across the hydrophobic, porous sheet membrane to the vacuum side of the membrane. The rate at which water evaporates, and therefore, the rate at which the flowing water is cooled, is a function of the difference between the water saturation pressure on the water side of the membrane, and the pressure on the vacuum side of the membrane. The primary theory is that the hydrophobic sheet membrane retains water, but permits vapor pass-through when the vapor side pressure is less than the water saturation pressure. This results in evaporative cooling of the remaining water.

  12. Evaporation, Condensation, and Precipitation

    NSDL National Science Digital Library

    Miss Brown

    2009-10-21

    After completion of this project students should have an understanding of evaporation, condensation, and precipitation in the water cycle. Use the websites provided to answer the questions. Record your answers on the spreadsheet provided. Do you understand how the water cycle works? Begin by watching this short video about the water cycle.water cycle video Use the website to define condensation, precipitation, and evaporation?water cycle List the different types of precipitation from the site.types of precipitation Follow the directions to the experiment on this website to get a better understanding of how evaporation takes ...

  13. Some methods of oil and gas reserve estimation in Azerbaijan

    SciTech Connect

    Abasov, M.T.; Buryakovsky, L.A.; Kondrushkin, Y.M.; Dzhevanshir, R.D.; Bagarov, T.Y. [Azerbaijan Academy of Sciences, Baku (Azerbaijan); Chilingar, G.V. [Univ. of Southern California, Los Angeles, CA (United States). Dept. of Civil and Environmental Engineering

    1997-08-01

    This article deals with the scientific and practical problems related to estimating oil and gas reserves in terrigenous reservoirs of the Productive Series of middle Pliocene and in Upper Cretaceous volcanic and sedimentary rocks. The deposits in question are spread over onshore Azerbaijan and adjacent offshore areas in the Caspian Sea and are approximately 6.5 km deep. This article presents lithologic, stratigraphic, and petrophysical criteria used for selecting prospects for reserve estimation. Also presented are information on structure of rocks and estimation of their lithologic and physical properties. New methods for the interpretation and application of petrophysical and logging data, as well as statistical estimation of reserves, in complex volcaniclastic reservoir rocks, are also discussed.

  14. Apparatus and method for gas turbine active combustion control system

    NASA Technical Reports Server (NTRS)

    Umeh, Chukwueloka (Inventor); Kammer, Leonardo C. (Inventor); Shah, Minesh (Inventor); Fortin, Jeffrey B. (Inventor); Knobloch, Aaron (Inventor); Myers, William J. (Inventor); Mancini, Alfred Albert (Inventor)

    2011-01-01

    An Active Combustion Control System and method provides for monitoring combustor pressure and modulating fuel to a gas turbine combustor to prevent combustion dynamics and/or flame extinguishments. The system includes an actuator, wherein the actuator periodically injects pulsed fuel into the combustor. The apparatus also includes a sensor connected to the combustion chamber down stream from an inlet, where the sensor generates a signal detecting the pressure oscillations in the combustor. The apparatus controls the actuator in response to the sensor. The apparatus prompts the actuator to periodically inject pulsed fuel into the combustor at a predetermined sympathetic frequency and magnitude, thereby controlling the amplitude of the pressure oscillations in the combustor by modulating the natural oscillations.

  15. Simultaneous heat and mass transfer inside a vertical channel in evaporating a heated falling glycols liquid film

    NASA Astrophysics Data System (ADS)

    Nait Alla, Abderrahman; Feddaoui, M'barek; Meftah, Hicham

    2015-03-01

    The interactive effects of heat and mass transfer in the evaporation of ethylene and propylene glycol flowing as falling films on vertical channel was investigated. The liquid film falls along a left plate which is externally subjected to a uniform heat flux while the right plate is the dry wall and is kept thermally insulated. The model solves the coupled governing equations in both phases together with the boundary and interfacial conditions. The systems of equations obtained by using an implicit finite difference method are solved by Tridiagonal Matrix Algorithm. The influence of the inlet liquid flow, Reynolds number in the gas flow and the wall heat flux on the intensity of heat and mass transfers are examined. A comparison between the results obtained for studied glycols and water in the same conditions is made. The results indicate that water evaporates in more intense way in comparison to glycols and the increase of gas flow rate tends to improve slightly the evaporation.

  16. Method for removing metal vapor from gas streams

    DOEpatents

    Ahluwalia, R. K. (6440 Hillcrest Dr., Burr Ridge, IL 60521); Im, K. H. (925 Lehigh Cir., Naperville, IL 60565)

    1996-01-01

    A process for cleaning an inert gas contaminated with a metallic vapor, such as cadmium, involves withdrawing gas containing the metallic contaminant from a gas atmosphere of high purity argon; passing the gas containing the metallic contaminant to a mass transfer unit having a plurality of hot gas channels separated by a plurality of coolant gas channels; cooling the contaminated gas as it flows upward through the mass transfer unit to cause contaminated gas vapor to condense on the gas channel walls; regenerating the gas channels of the mass transfer unit; and, returning the cleaned gas to the gas atmosphere of high purity argon. The condensing of the contaminant-containing vapor occurs while suppressing contaminant particulate formation, and is promoted by providing a sufficient amount of surface area in the mass transfer unit to cause the vapor to condense and relieve supersaturation buildup such that contaminant particulates are not formed. Condensation of the contaminant is prevented on supply and return lines in which the contaminant containing gas is withdrawn and returned from and to the electrorefiner and mass transfer unit by heating and insulating the supply and return lines.

  17. Method for removing metal vapor from gas streams

    DOEpatents

    Ahluwalia, R.K.; Im, K.H.

    1996-04-02

    A process for cleaning an inert gas contaminated with a metallic vapor, such as cadmium, involves withdrawing gas containing the metallic contaminant from a gas atmosphere of high purity argon; passing the gas containing the metallic contaminant to a mass transfer unit having a plurality of hot gas channels separated by a plurality of coolant gas channels; cooling the contaminated gas as it flows upward through the mass transfer unit to cause contaminated gas vapor to condense on the gas channel walls; regenerating the gas channels of the mass transfer unit; and, returning the cleaned gas to the gas atmosphere of high purity argon. The condensing of the contaminant-containing vapor occurs while suppressing contaminant particulate formation, and is promoted by providing a sufficient amount of surface area in the mass transfer unit to cause the vapor to condense and relieve supersaturation buildup such that contaminant particulates are not formed. Condensation of the contaminant is prevented on supply and return lines in which the contaminant containing gas is withdrawn and returned from and to the electrorefiner and mass transfer unit by heating and insulating the supply and return lines. 13 figs.

  18. Method for controlling exhaust gas heat recovery systems in vehicles

    DOEpatents

    Spohn, Brian L.; Claypole, George M.; Starr, Richard D

    2013-06-11

    A method of operating a vehicle including an engine, a transmission, an exhaust gas heat recovery (EGHR) heat exchanger, and an oil-to-water heat exchanger providing selective heat-exchange communication between the engine and transmission. The method includes controlling a two-way valve, which is configured to be set to one of an engine position and a transmission position. The engine position allows heat-exchange communication between the EGHR heat exchanger and the engine, but does not allow heat-exchange communication between the EGHR heat exchanger and the oil-to-water heat exchanger. The transmission position allows heat-exchange communication between the EGHR heat exchanger, the oil-to-water heat exchanger, and the engine. The method also includes monitoring an ambient air temperature and comparing the monitored ambient air temperature to a predetermined cold ambient temperature. If the monitored ambient air temperature is greater than the predetermined cold ambient temperature, the two-way valve is set to the transmission position.

  19. Estimating soil water evaporation using radar measurements

    NASA Technical Reports Server (NTRS)

    Sadeghi, Ali M.; Scott, H. D.; Waite, W. P.; Asrar, G.

    1988-01-01

    Field studies were conducted to evaluate the application of radar reflectivity as compared with the shortwave reflectivity (albedo) used in the Idso-Jackson equation for the estimation of daily evaporation under overcast sky and subhumid climatic conditions. Soil water content, water potential, shortwave and radar reflectivity, and soil and air temperatures were monitored during three soil drying cycles. The data from each cycle were used to calculate daily evaporation from the Idso-Jackson equation and from two other standard methods, the modified Penman and plane of zero-flux. All three methods resulted in similar estimates of evaporation under clear sky conditions; however, under overcast sky conditions, evaporation fluxes computed from the Idso-Jackson equation were consistently lower than the other two methods. The shortwave albedo values in the Idso-Jackson equation were then replaced with radar reflectivities and a new set of total daily evaporation fluxes were calculated. This resulted in a significant improvement in computed soil evaporation fluxes from the Idso-Jackson equation, and a better agreement between the three methods under overcast sky conditions.

  20. Method for removal of sulfur compounds from a gas

    SciTech Connect

    Frech, K.J.; Tazuma, J.J.

    1981-08-11

    This invention relates to a process for the removal of sulfur compounds from a gas stream which consists of contacting said gas stream with alkali metal salts of sulfonamides or resins containing sulfonamide functionalities.

  1. Evaporation and Thermal Balance of Tiny HI Clouds

    E-print Network

    Jonathan D. Slavin

    2006-10-10

    We discuss the thermal evaporation of tiny HI clouds in the interstellar medium. Cold neutral clouds will take ~10^6 - 10^7 yr to evaporate if they are embedded in warm neutral gas and about half as long if embedded in hot gas. Heat flux saturation effects severely reduce the evaporation rate of tiny cold neutral medium (CNM) clouds into hot gas. For CNM clouds embedded in warm neutral medium (WNM) the much lower conductivity results in slower evaporation. This mass loss rate could still be significant, however, if the environment is relatively quiescent. Partial ionization of the WNM gas would substantially reduce the conductivity and lengthen the lifetime of the tiny HI clouds. The ultimate importance of thermal conduction to cloud evolution will depend on the role of turbulence and the characteristics of the medium in which the clouds are embedded.

  2. Evaporation of an atomic beam on a material surface

    SciTech Connect

    Reinaudi, G.; Lahaye, T.; Couvert, A.; Wang, Z.; Guery-Odelin, D. [Laboratoire Kastler Brossel, 24 rue Lhomond, F-75231 Paris Cedex 05 (France)

    2006-03-15

    We report on the implementation of evaporative cooling of a magnetically guided beam by adsorption on a ceramic surface. We use a transverse magnetic field to shift locally the beam towards the surface, where atoms are selectively evaporated. With a 5-mm-long ceramic piece, we gain a factor of 1.5{+-}0.2 on the phase-space density. Our results are consistent with a 100% efficiency of this evaporation process. The flexible implementation that we have demonstrated, combined with the very local action of the evaporation zone, makes this method particularly suited for the evaporative cooling of a beam.

  3. An improved method for the determination of the wellstream gas specific gravity for retrograde gases

    E-print Network

    Gold, David Keith

    1988-01-01

    calculations. The wellstream gas specific gravity for a retrograde gas reservoir can be determined using two methods. The first method requires fluid samples of the primary separator liquid and gas to be obtained from the well, their respective compositions... to retrograde gas condensates were used in the development of E1lerts' correlation. Using the fluid samples in this study, Leshikar's correlation for VEQ results in an average absolute error of 16K, A different approach was taken in the development...

  4. Mixed feed evaporator

    DOEpatents

    Vakil, Himanshu B. (Schenectady, NY); Kosky, Philip G. (Ballston Lake, NY)

    1982-01-01

    In the preparation of the gaseous reactant feed to undergo a chemical reaction requiring the presence of steam, the efficiency of overall power utilization is improved by premixing the gaseous reactant feed with water and then heating to evaporate the water in the presence of the gaseous reactant feed, the heating fluid utilized being at a temperature below the boiling point of water at the pressure in the volume where the evaporation occurs.

  5. Evaporated Cermet Materials

    Microsoft Academic Search

    G. Riddle

    1967-01-01

    Both resistive and insulating cermets were obtained from experiments on co-evaporated materials. Stable resistivities in the 1000 micro-ohm-centimeter range were obtained from mixtures of germanium and chromium, and from a reaction product of aluminum and alumina. Glassy dielectric films were obtained from reaction products of aluminum and alumina, and from aluminum and silicon monoxide. The factors that control these co-evaporation

  6. CaO-MgO-Al 2o 3SiO 2 liquids: chemical and isotopic effects of Mg and Si evaporation in a closed system of solar composition

    Microsoft Academic Search

    L. Grossman; A. V. Fedkin

    2003-01-01

    A method is shown for calculating vapor pressures over a CMAS droplet in a gas of any composition. It is applied to the problem of the evolution of the chemical and Mg and Si isotopic composition of a completely molten droplet having the composition of a likely refractory inclusion precursor during its evaporation into the complementary, i.e. modified solar, gas

  7. Method for removing undesired particles from gas streams

    DOEpatents

    Durham, Michael Dean (Castle Rock, CO); Schlager, Richard John (Aurora, CO); Ebner, Timothy George (Westminster, CO); Stewart, Robin Michele (Arvada, CO); Hyatt, David E. (Denver, CO); Bustard, Cynthia Jean (Littleton, CO); Sjostrom, Sharon (Denver, CO)

    1998-01-01

    The present invention discloses a process for removing undesired particles from a gas stream including the steps of contacting a composition containing an adhesive with the gas stream; collecting the undesired particles and adhesive on a collection surface to form an aggregate comprising the adhesive and undesired particles on the collection surface; and removing the agglomerate from the collection zone. The composition may then be atomized and injected into the gas stream. The composition may include a liquid that vaporizes in the gas stream. After the liquid vaporizes, adhesive particles are entrained in the gas stream. The process may be applied to electrostatic precipitators and filtration systems to improve undesired particle collection efficiency.

  8. Evaporative cooling of magnetically trapped atomic molybdenum

    SciTech Connect

    Hancox, Cindy I.; Hummon, Matthew T.; Nguyen, Scott V.; Doyle, John M. [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2005-03-01

    We have magnetically trapped and evaporatively cooled atomic molybdenum. Using a cryogenic helium buffer gas, 2x10{sup 10} molybdenum atoms are loaded into a magnetic trap at an initial temperature of 500 mK. The molybdenum atoms undergo two-body decay with a measured inelastic rate constant of g{sub in}=(1.2{+-}0.6)x10{sup -12} cm{sup 3} s{sup -1} for the initial conditions after loading. The molybdenum atoms are cooled by adiabatic expansion and forced evaporation to 200 mK.

  9. The effect of carrier gas flow rate and source cell temperature on low pressure organic vapor phase deposition simulation by direct simulation Monte Carlo method

    PubMed Central

    Wada, Takao; Ueda, Noriaki

    2013-01-01

    The process of low pressure organic vapor phase deposition (LP-OVPD) controls the growth of amorphous organic thin films, where the source gases (Alq3 molecule, etc.) are introduced into a hot wall reactor via an injection barrel using an inert carrier gas (N2 molecule). It is possible to control well the following substrate properties such as dopant concentration, deposition rate, and thickness uniformity of the thin film. In this paper, we present LP-OVPD simulation results using direct simulation Monte Carlo-Neutrals (Particle-PLUS neutral module) which is commercial software adopting direct simulation Monte Carlo method. By estimating properly the evaporation rate with experimental vaporization enthalpies, the calculated deposition rates on the substrate agree well with the experimental results that depend on carrier gas flow rate and source cell temperature. PMID:23674843

  10. Method and apparatus for processing filling gas from a coke oven battery

    SciTech Connect

    Polenz, J.; Wagner, H.

    1981-08-11

    An improved coke oven battery and an improved method for production of coke and byproducts are provided. The filling gas escaping during the filling of the oven chambers with coal is initially rendered inert by admixing flue gas. Then the resulting gas mixture of filling gas and flue gas is withdrawn via a conduit fed with flushing liquor from the coke oven gas off-take main and is added to the raw coke oven gas after the coke oven gas off-take main. The tar and coal containing flushing liquor coming from the filling gas conduit is fed back to the coke oven gas off-take main after removal of the tar.

  11. Apparatus for the liquefaction of a gas and methods relating to same

    DOEpatents

    Turner, Terry D. (Idaho Falls, ID) [Idaho Falls, ID; Wilding, Bruce M. (Idaho Falls, ID) [Idaho Falls, ID; McKellar, Michael G. (Idaho Falls, ID) [Idaho Falls, ID

    2009-12-29

    Apparatuses and methods are provided for producing liquefied gas, such as liquefied natural gas. In one embodiment, a liquefaction plant may be coupled to a source of unpurified natural gas, such as a natural gas pipeline at a pressure letdown station. A portion of the gas is drawn off and split into a process stream and a cooling stream. The cooling stream may be sequentially pass through a compressor and an expander. The process stream may also pass through a compressor. The compressed process stream is cooled, such as by the expanded cooling stream. The cooled, compressed process stream is expanded to liquefy the natural gas. A gas-liquid separator separates the vapor from the liquid natural gas. A portion of the liquid gas may be used for additional cooling. Gas produced within the system may be recompressed for reintroduction into a receiving line.

  12. Evaporative cooling of spin-polarized atomic hydrogen

    NASA Astrophysics Data System (ADS)

    Masuhara, Naoto; Doyle, John M.; Sandberg, Jon C.; Kleppner, Daniel; Greytak, Thomas J.; Hess, Harald F.; Kochanski, Greg P.

    1988-08-01

    A gas hydrogen atoms, confined in a static magnetic trap, has been evaporatively cooled to temperatures of a few millikelvin. The initial trap configuration held the gas at 38 mK for as long as 5 h. Evaporative cooling reduced the temperature to 3.0 mK while maintaining the central density at 7.6×1012 cm-3. These values were determined by measurement of the rate of electronic spin relaxation and are in agreement with model calculations. Further cooling to 1 mK (inferred from the model) has been achieved. Measurements were made of the efficiency of the evaporative cooling process.

  13. Calculation of two-phase flow in gas turbine combustors

    Microsoft Academic Search

    A. K. Tolpadi

    1995-01-01

    A method is presented for computing steady two-phase turbulent combusting flow in a gas turbine combustor. The gas phase equations are solved in an Eulerian frame of reference. The two-phase calculations are performed by using a liquid droplet spray combustion a model and treating the motion of the evaporating fuel droplets in a Lagrangian frame of reference. The numerical algorithm

  14. Simulation of Mist Transport for Gas Turbine Inlet Air Cooling

    Microsoft Academic Search

    Ting Wang; Xianchang Li; Venu Pinninti

    2008-01-01

    The output and efficiency of gas turbines are reduced significantly during the summer. Gas turbine inlet air-cooling is considered a simple and effective method to increase the power output as well as thermal efficiency. Among various cooling schemes, fog cooling (a direct evaporative cooling) has gained increasing popularity due to its simplicity and low installation cost. During fog cooling, water

  15. Adiabatic burst evaporation from bicontinuous nanoporous membranes.

    PubMed

    Ichilmann, Sachar; Rücker, Kerstin; Haase, Markus; Enke, Dirk; Steinhart, Martin; Xue, Longjian

    2015-05-14

    Evaporation of volatile liquids from nanoporous media with bicontinuous morphology and pore diameters of a few 10 nm is an ubiquitous process. For example, such drying processes occur during syntheses of nanoporous materials by sol-gel chemistry or by spinodal decomposition in the presence of solvents as well as during solution impregnation of nanoporous hosts with functional guests. It is commonly assumed that drying is endothermic and driven by non-equilibrium partial pressures of the evaporating species in the gas phase. We show that nearly half of the liquid evaporates in an adiabatic mode involving burst-like liquid-to-gas conversions. During single adiabatic burst evaporation events liquid volumes of up to 10(7) ?m(3) are converted to gas. The adiabatic liquid-to-gas conversions occur if air invasion fronts get unstable because of the built-up of high capillary pressures. Adiabatic evaporation bursts propagate avalanche-like through the nanopore systems until the air invasion fronts have reached new stable configurations. Adiabatic cavitation bursts thus compete with Haines jumps involving air invasion front relaxation by local liquid flow without enhanced mass transport out of the nanoporous medium and prevail if the mean pore diameter is in the range of a few 10 nm. The results reported here may help optimize membrane preparation via solvent-based approaches, solution-loading of nanopore systems with guest materials as well as routine use of nanoporous membranes with bicontinuous morphology and may contribute to better understanding of adsorption/desorption processes in nanoporous media. PMID:25926406

  16. Adiabatic burst evaporation from bicontinuous nanoporous membranes

    NASA Astrophysics Data System (ADS)

    Ichilmann, Sachar; Rücker, Kerstin; Haase, Markus; Enke, Dirk; Steinhart, Martin; Xue, Longjian

    2015-05-01

    Evaporation of volatile liquids from nanoporous media with bicontinuous morphology and pore diameters of a few 10 nm is an ubiquitous process. For example, such drying processes occur during syntheses of nanoporous materials by sol-gel chemistry or by spinodal decomposition in the presence of solvents as well as during solution impregnation of nanoporous hosts with functional guests. It is commonly assumed that drying is endothermic and driven by non-equilibrium partial pressures of the evaporating species in the gas phase. We show that nearly half of the liquid evaporates in an adiabatic mode involving burst-like liquid-to-gas conversions. During single adiabatic burst evaporation events liquid volumes of up to 107 ?m3 are converted to gas. The adiabatic liquid-to-gas conversions occur if air invasion fronts get unstable because of the built-up of high capillary pressures. Adiabatic evaporation bursts propagate avalanche-like through the nanopore systems until the air invasion fronts have reached new stable configurations. Adiabatic cavitation bursts thus compete with Haines jumps involving air invasion front relaxation by local liquid flow without enhanced mass transport out of the nanoporous medium and prevail if the mean pore diameter is in the range of a few 10 nm. The results reported here may help optimize membrane preparation via solvent-based approaches, solution-loading of nanopore systems with guest materials as well as routine use of nanoporous membranes with bicontinuous morphology and may contribute to better understanding of adsorption/desorption processes in nanoporous media.

  17. DISCUSSION OF PAPER BY G. EARL HARBECK, JR., AND GORDON E. KOBERG, 'A METHOD OF EVALUATING THE EFFECT OF A MONOMOLECULAR FILM IN SUPPRESSING RESERVOIR EVAPORATION 

    Microsoft Academic Search

    William Halcrow

    1959-01-01

    The writer may add that he has carried out water budget analyses of Lake Nyasa for part of each year over a period of many years [Cochrane, 1956] and found that the natural evaporation varied considerably from year to year. He has now completed a similar investigation using lake levels of the Caspian Sea since 1837 and finds support there

  18. Chromatographic method of determining the components of the return coke oven gas

    SciTech Connect

    Pakhomov, V.I.; Gavrilov, N.N.; Aleshin, V.I.; Efremkov, I.Ya.

    1982-01-01

    In plant laboratories, the composition of the return coke oven gas is usually determined by means of a VTI-2 gas analyzer. The analysis method is laborious and prolonged and the error of determination of the content of certain components reaches 15 relative percent. In order to solve these problems, a method of analyzing the oven gas was developed using a three-column chromatograph with a combination detector (by thermal conductivity and heat of combustion. This analysis method is detailed. (JMT)

  19. Gas chromatographic method for detection of urinary sucralose: application to the assessment of intestinal permeability

    Microsoft Academic Search

    Ashkan Farhadi; Ali Keshavarzian; Earle W Holmes; Jeremy Fields; Lei Zhang; Ali Banan

    2003-01-01

    We developed a capillary column gas chromatography (CCGC) method for the measurement of urinary sucralose (S) and three other sugar probes including, sucrose, lactulose (L) and mannitol (M) for use in in vivo studies of intestinal permeability. We compared the capillary method with a packed column gas chromatography (PCGC) method. We also investigated a possible role for sucralose as a

  20. Methods For Delivering Liquified Gas To An Engine

    DOEpatents

    Bingham, Dennis N. (Idaho Falls, ID); Wilding, Bruce M. (Idaho Falls, ID); O'Brien, James E. (Idaho Falls, ID); Siahpush, Ali S. (Idaho Falls, ID); Brown, Kevin B. (Idaho Falls, ID)

    2003-09-16

    A liquified gas delivery system for a motorized platform includes a holding tank configured to receive liquified gas. A first conduit extends from a vapor holding portion of the tank to a valve device. A second conduit extends from a liquid holding portion of the tank to the valve device. Fluid coupled to the valve device is a vaporizer which is in communication with an engine. The valve device selectively withdraws either liquified gas or liquified gas vapor from the tank depending on the pressure within the vapor holding portion of the tank. Various configurations of the delivery system can be utilized for pressurizing the tank during operation.

  1. Method for high temperature mercury capture from gas streams

    DOEpatents

    Granite, E.J.; Pennline, H.W.

    2006-04-25

    A process to facilitate mercury extraction from high temperature flue/fuel gas via the use of metal sorbents which capture mercury at ambient and high temperatures. The spent sorbents can be regenerated after exposure to mercury. The metal sorbents can be used as pure metals (or combinations of metals) or dispersed on an inert support to increase surface area per gram of metal sorbent. Iridium and ruthenium are effective for mercury removal from flue and smelter gases. Palladium and platinum are effective for mercury removal from fuel gas (syngas). An iridium-platinum alloy is suitable for metal capture in many industrial effluent gas streams including highly corrosive gas streams.

  2. Methods For Delivering Liquified Gas To An Engine

    DOEpatents

    Bingham, Dennis N. (Idaho Falls, ID); Wilding, Bruce M. (Idaho Falls, ID); O'Brien, James E. (Idaho Falls, ID); Siahpush, Ali S. (Idaho Falls, ID); Brown, Kevin B. (Idaho Falls, ID)

    2005-10-11

    A liquified gas delivery system for a motorized platform includes a holding tank configured to receive liquified gas. A first conduit extends from a vapor holding portion of the tank to a valve device. A second conduit extends from a liquid holding portion of the tank to the valve device. Fluid coupled to the valve device is a vaporizer which is in communication with an engine. The valve device selectively withdraws either liquified gas or liquified gas vapor from the tank depending on the pressure within the vapor holding portion of the tank. Various configurations of the delivery system can be utilized for pressurizing the tank during operation.

  3. Systems and method for delivering liquified gas to an engine

    DOEpatents

    Bingham, Dennis N. (Idaho Falls, ID); Wilding, Bruce M. (Idaho Falls, ID); O'Brien, James E. (Idaho Falls, ID); Siahpush, Ali S. (Idaho Falls, ID); Brown, Kevin B. (Idaho Falls, ID)

    2002-01-01

    A liquified gas delivery system for a motorized platform includes a holding tank configured to receive liquified gas. A first conduit extends from a vapor holding portion of the tank to a valve device. A second conduit extends from a liquid holding portion of the tank to the valve device. Fluid coupled to the valve device is a vaporizer which is in communication with an engine. The valve device selectively withdraws either liquified gas or liquified gas vapor from the tank depending on the pressure within the vapor holding portion of the tank. Various configurations of the delivery system can be utilized for pressurizing the tank during operation.

  4. A method for the removal of elemental mercury from a gas stream

    SciTech Connect

    Mendelsohn, Marshall H.; Huang, Hann-Sheng

    1997-12-01

    A method is provided to remove elemental mercury from a gas stream by reacting the gas stream with an oxidizing solution to convert the elemental mercury to soluble mercury compounds. Other constituents are also oxidized. The gas stream is then passed through a wet scrubber to remove the mercuric compounds and oxidized constituents.

  5. Method for the removal of elemental mercury from a gas stream

    DOEpatents

    Mendelsohn, Marshall H. (Downers Grove, IL); Huang, Hann-Sheng (Darien, IL)

    1999-01-01

    A method is provided to remove elemental mercury from a gas stream by reacting the gas stream with an oxidizing solution to convert the elemental mercury to soluble mercury compounds. Other constituents are also oxidized. The gas stream is then passed through a wet scrubber to remove the mercuric compounds and oxidized constituents.

  6. Multicomponent gas mixture air bearing modeling via lattice Boltzmann method

    NASA Astrophysics Data System (ADS)

    Tae Kim, Woo; Kim, Dehee; Hari Vemuri, Sesha; Kang, Soo-Choon; Seung Chung, Pil; Jhon, Myung S.

    2011-04-01

    As the demand for ultrahigh recording density increases, development of an integrated head disk interface (HDI) modeling tool, which considers the air bearing and lubricant film morphology simultaneously is of paramount importance. To overcome the shortcomings of the existing models based on the modified Reynolds equation (MRE), the lattice Boltzmann method (LBM) is a natural choice in modeling high Knudsen number (Kn) flows owing to its advantages over conventional methods. The transient and parallel nature makes this LBM an attractive tool for the next generation air bearing design. Although LBM has been successfully applied to single component systems, a multicomponent system analysis has been thwarted because of the complexity in coupling the terms for each component. Previous studies have shown good results in modeling immiscible component mixtures by use of an interparticle potential. In this paper, we extend our LBM model to predict the flow rate of high Kn pressure-driven flows in multicomponent gas mixture air bearings, such as the air-helium system. For accurate modeling of slip conditions near the wall, we adopt our LBM scheme with spatially dependent relaxation times for air bearings in HDIs. To verify the accuracy of our code, we tested our scheme via simple two-dimensional benchmark flows. In the pressure-driven flow of an air-helium mixture, we found that the simple linear combination of pure helium and pure air flow rates, based on helium and air mole fraction, gives considerable error when compared to our LBM calculation. Hybridization with the existing MRE database can be adopted with the procedure reported here to develop the state-of-the-art slider design software.

  7. Apparatus for the liquefaction of natural gas and methods relating to same

    DOEpatents

    Turner, Terry D. (Ammon, ID); Wilding, Bruce M. (Idaho Falls, ID); McKellar, Michael G. (Idaho Falls, ID)

    2009-09-22

    An apparatus and method for producing liquefied natural gas. A liquefaction plant may be coupled to a source of unpurified natural gas, such as a natural gas pipeline at a pressure letdown station. A portion of the gas is drawn off and split into a process stream and a cooling stream. The cooling stream passes through an expander creating work output. A compressor may be driven by the work output and compresses the process stream. The compressed process stream is cooled, such as by the expanded cooling stream. The cooled, compressed process stream is expanded to liquefy the natural gas. A gas-liquid separator separates a vapor from the liquid natural gas. A portion of the liquid gas is used for additional cooling. Gas produced within the system may be recompressed for reintroduction into a receiving line or recirculation within the system for further processing.

  8. Method and apparatus for gas separation and synthesis

    Microsoft Academic Search

    Keefer

    1987-01-01

    Pressure swing adsorption gas separations are conducted inside an open loop Stirling cycle apparatus which may operate as an engine, refrigerator or heat pump. Adsorbent surfaces are associated with the thermal regenerators of the Stirling cycle apparatus, so that a preferentially adsorbed gas fraction is concentrated by parametric pumping into a colder end of an engine or into a warmer

  9. Gas pipeline leak detection system using the online simulation method

    Microsoft Academic Search

    Reiko Maeshima; Akira Kinoshita; Hitoshi Shiraishi; Ichiro Koshijima

    2000-01-01

    Management of natural gas pipeline is an important task for economical and safety operation, loss prevention and environmental protection from methane emission. A leak detection of gas pipeline, therefore, plays a key role in the overall integrity management for a pipeline system. Especially for a long pipeline operated alongside of densely populated areas, a leak detection system is an indispensable

  10. FIELD COMPARISON OF PORTABLE GAS CHROMATOGRAPHS WITH METHOD TO-14

    EPA Science Inventory

    A field-deployable prototype fast gas chromatograph (FGC) and two commercially-available portable gas chromatographs (PGC) were evaluated by measuring organic vapors in ambient air at a field monitoring site in metropolitan San Juan, Puerto Rico. he data were compared with simult...

  11. A steady rotational plane gas flow problem by hodograph method

    NASA Astrophysics Data System (ADS)

    Chandna, O. P.; Murgai, A.; Rankin, G. W.

    The Prim and Nemenyi (1948) study of the geometries of plane, steady rotational flows, for the case of an inviscid perfect gas, whose velocity magnitude is constant along each individual streamline, is presently applied by means of the hodographic technique to steady rotational plane gas flows. Both the geometry of the flows and their solutions are obtained.

  12. Method for removing undesired particles from gas streams

    DOEpatents

    Durham, M.D.; Schlager, R.J.; Ebner, T.G.; Stewart, R.M.; Hyatt, D.E.; Bustard, C.J.; Sjostrom, S.

    1998-11-10

    The present invention discloses a process for removing undesired particles from a gas stream including the steps of contacting a composition containing an adhesive with the gas stream; collecting the undesired particles and adhesive on a collection surface to form an aggregate comprising the adhesive and undesired particles on the collection surface; and removing the agglomerate from the collection zone. The composition may then be atomized and injected into the gas stream. The composition may include a liquid that vaporizes in the gas stream. After the liquid vaporizes, adhesive particles are entrained in the gas stream. The process may be applied to electrostatic precipitators and filtration systems to improve undesired particle collection efficiency. 11 figs.

  13. Influence of surface wettability on transport mechanisms governing water droplet evaporation.

    PubMed

    Pan, Zhenhai; Weibel, Justin A; Garimella, Suresh V

    2014-08-19

    Prediction and manipulation of the evaporation of small droplets is a fundamental problem with importance in a variety of microfluidic, microfabrication, and biomedical applications. A vapor-diffusion-based model has been widely employed to predict the interfacial evaporation rate; however, its scope of applicability is limited due to incorporation of a number of simplifying assumptions of the physical behavior. Two key transport mechanisms besides vapor diffusion-evaporative cooling and natural convection in the surrounding gas-are investigated here as a function of the substrate wettability using an augmented droplet evaporation model. Three regimes are distinguished by the instantaneous contact angle (CA). In Regime I (CA ? 60°), the flat droplet shape results in a small thermal resistance between the liquid-vapor interface and substrate, which mitigates the effect of evaporative cooling; upward gas-phase natural convection enhances evaporation. In Regime II (60 ? CA ? 90°), evaporative cooling at the interface suppresses evaporation with increasing contact angle and counterbalances the gas-phase convection enhancement. Because effects of the evaporative cooling and gas-phase convection mechanisms largely neutralize each other, the vapor-diffusion-based model can predict the overall evaporation rates in this regime. In Regime III (CA ? 90°), evaporative cooling suppresses the evaporation rate significantly and reverses entirely the direction of natural convection induced by vapor concentration gradients in the gas phase. Delineation of these counteracting mechanisms reconciles previous debate (founded on single-surface experiments or models that consider only a subset of the governing transport mechanisms) regarding the applicability of the classic vapor-diffusion model. The vapor diffusion-based model cannot predict the local evaporation flux along the interface for high contact angle (CA ? 90°) when evaporative cooling is strong and the temperature gradient along the interface determines the peak local evaporation flux. PMID:25105726

  14. How do drops evaporate?

    NASA Astrophysics Data System (ADS)

    Murisic, Nebojsa; Kondic, Lou

    2007-11-01

    The problem of evaporating drops with non-pinned contact line, although seemingly trivial, so far lacks satisfactory theoretical description. In particular, there has been much discussion regarding appropriate evaporative mass flux model. We make an attempt to resolve this issue by comparing our experimental data with the results of several mathematical models for evaporating drops. After describing experimental procedure, we propose several models for mass flux and develop a governing equation for evolution of drop's thickness. Two-dimensional numerical results are then compared to the experimental results, and the most appropriate mass flux model is identified. Finally, we propose the governing equation for the full 3D system and present some new numerical results related to curious phenomena, where so-called ``octopus-shaped'' instabilities appear ahead of the contact line of volatile dropsootnotetextY. Gotkis, I. Ivanov, N. Murisic, L. Kondic, Phys. Rev. Lett. 97, 186101 (2006)..

  15. Evaporator Development for an Evaporative Heat Pipe System

    NASA Technical Reports Server (NTRS)

    Peters, Leigh C.

    2004-01-01

    As fossil fuel resources continue to deplete, research for alternate power sources continues to develop. One of these alternate technologies is fuel cells. They are a practical fuel source able to provide significant amounts of power for applications from laptops to automobiles and their only byproduct is water. However, although this technology is over a century old and NASA has been working with it since the early 1960 s there is still room for improvement. The research I am involved in at NASA's Glenn Research Center is focusing on what is called a regenerative fuel cell system. The unique characteristic of this type of system is that it used an outside power source to create electrolysis of the water it produces and it then reuses the hydrogen and oxygen to continue producing power. The advantage of this type of system is that, for example, on space missions it can use solar power to recharge its gas supplies between periods when the object being orbited blocks out the sun. This particular system however is far from completion. This is because of the many components that are required to make up a fuel cell that need to be tested individually. The specific part of the system that is being worked on this summer of 2004 is the cooling system. The fuel cell stack, that is the part that actually creates the power, also produces a lot of heat. When not properly cooled, it has been known to cause fires which, needless to say are not conducive to the type of power that is trying to be created. In order to cool the fuel cell stack in this system we are developing a heat pipe cooling system. One of the main components of a heat pipe cooling system is what is known as the evaporator, and that is what happens to be the part of the system we are developing this summer. In most heat pipe systems the evaporator is a tube in which the working fluid is cooled and then re-circulated through the system to absorb more heat energy from the fuel cell stack. For this system, instead of a tube, the evaporator is made up of a stack-up of screen material and absorbent membranes inside a stainless steel shell and held together by a film adhesive and epoxy. There is an initial design for this flat plate evaporator, however is has not yet been made. The components of the stack-up are known, so all testing is focused on how it will all go together. This includes finding an appropriate epoxy to make the evaporator conductive all the way through and finding a way to hold the required tight tolerances as the stainless steel outer shell is put together. By doing the tests on smaller samples of the stack-ups and then testing the fill size component, the final flat plate evaporator will reach its final design so that research can continue on other parts of the regenerative fue1 cell system, and another step in the improvement of fue1 cell technology can be made.

  16. Methods of Off-Gas Flammability Control for DWPF Melter Off-Gas System at Savannah River Site

    SciTech Connect

    Choi, A.S. [Westinghouse Savannah River Company, AIKEN, SC (United States); Iverson, D.C.

    1996-05-02

    Several key operating variables affecting off-gas flammability in a slurry-fed radioactive waste glass melter are discussed, and the methods used to prevent potential off-gas flammability are presented. Two models have played a central role in developing such methods. The first model attempts to describe the chemical events occurring during the calcining and melting steps using a multistage thermodynamic equilibrium approach, and it calculates the compositions of glass and calcine gases. Volatile feed components and calcine gases are fed to the second model which then predicts the process dynamics of the entire melter off-gas system including off-gas flammability under both steady state and various transient operating conditions. Results of recent simulation runs are also compared with available data

  17. Diffusion NMR Methods Applied to Xenon Gas for Materials Study

    E-print Network

    R. W. Mair; M. S. Rosen; R. Wang; D. G. Cory; R. L. Walsworth

    2002-11-09

    We report initial NMR studies of i) xenon gas diffusion in model heterogeneous porous media, and ii) continuous flow laser-polarized xenon gas. Both areas utilize the Pulsed Gradient Spin Echo techniques in the gas-phase, with the aim of obtaining more sophisticated information than just translational self-diffusion coefficients - a brief overview of this area is provided in the introduction. The heterogeneous or multiple-length scale model porous media consisted of random packs of mixed glass beads of two different sizes. We focus on observing the approach of the time-dependent gas diffusion coefficient, D(t), (an indicator of mean squared displacement) to the long-time asymptote, with the aim of understanding the long-length scale structural information that may be derived from a heterogeneous porous system. The Pade approximation is used to interpolate D(t) data between the short and long time limits. Initial studies of continuous flow laser-polarized xenon gas demonstrate velocity-sensitive imaging of much higher flows than can generally be obtained with liquids (20 - 200 mm/s). Gas velocity imaging is, however, found to be limited to a resolution of about 1 mm/s due to the high diffusivity of gases compared to liquids. We also present the first gas-phase NMR scattering, or diffusive-diffraction, data: namely, flow-enhanced structural features in the echo attenuation data from laser-polarized xenon flowing through a 2 mm glass bead pack.

  18. Integration of gas chromatography mass spectrometry methods for differentiating ricin preparation methods.

    PubMed

    Wunschel, David S; Melville, Angela M; Ehrhardt, Christopher J; Colburn, Heather A; Victry, Kristin D; Antolick, Kathryn C; Wahl, Jon H; Wahl, Karen L

    2012-05-01

    The investigation of crimes involving chemical or biological agents is infrequent, but presents unique analytical challenges. The protein toxin ricin is encountered more frequently than other agents and is found in the seeds of Ricinus communis, commonly known as the castor plant. Typically, the toxin is extracted from castor seeds utilizing a variety of different recipes that result in varying purity of the toxin. Moreover, these various purification steps can also leave or differentially remove a variety of exogenous and endogenous residual components with the toxin that may indicate the type and number of purification steps involved. We have applied three gas chromatography-mass spectrometry (GC-MS) based analytical methods to measure the variation in seed carbohydrates and castor oil ricinoleic acid, as well as the presence of solvents used for purification. These methods were applied to the same samples prepared using four previously identified toxin preparation methods, starting from four varieties of castor seeds. The individual data sets for seed carbohydrate profiles, ricinoleic acid, or acetone amount each provided information capable of differentiating different types of toxin preparations across seed types. However, the integration of the data sets using multivariate factor analysis provided a clear distinction of all samples based on the preparation method, independent of the seed source. In particular, the abundance of mannose, arabinose, fucose, ricinoleic acid, and acetone were shown to be important differentiating factors. These complementary tools provide a more confident determination of the method of toxin preparation than would be possible using a single analytical method. PMID:22416271

  19. Method of cooling gas only nozzle fuel tip

    DOEpatents

    Bechtel, William Theodore (Scotia, NY); Fitts, David Orus (Ballston Spa, NY); DeLeonardo, Guy Wayne (Glenville, NY)

    2002-01-01

    A diffusion flame nozzle gas tip is provided to convert a dual fuel nozzle to a gas only nozzle. The nozle tip diverts compressor discharge air from the passage feeding the diffusion nozzle air swirl vanes to a region vacated by removal of the dual fuel components, so that the diverted compressor discharge air can flow to and through effusion holes in the end cap plate of the nozzle tip. In a preferred embodiment, the nozzle gas tip defines a cavity for receiving the compressor discharge air from a peripheral passage of the nozzle for flow through the effusion openings defined in the end cap plate.

  20. Method and apparatus for scrubbing a gas containing powdered particles

    SciTech Connect

    Eversdijk, B.P.; Kamphuts, G.G.

    1981-03-24

    A scrubber is disclosed for separating powder particles from a gas stream comprising a closed vertical cylindrical housing having a tangential inlet for the gas stream and a concentric discharge pipe passing through the top of the housing for the removal of the purified gas stream; in which means are provided for flushing the lower portion of the inner wall of the housing. The flushing means comprises an annular gutter surrounding the housing and communicating with said inner wall by means of a large number of narrow passages. The level of the gutter is well above the lower end of the discharge pipe.

  1. Chemical characterization of Brickellia cavanillesii (Asteraceae) using gas chromatographic methods.

    PubMed

    Eshiet, Etetor R; Zhu, Jinqiu; Anderson, Todd A; Smith, Ernest E

    2014-03-01

    A methanol extract of lyophilized Brickellia cavanillesii was quantitatively analyzed using gas chromatographic (GC) techniques. The chromatographic methods employed were (i) GC-flame ionization detector (GC-FID), (ii) GC-mass spectrometry (GC-MS), and (iii) purge and trap GC-MS (P&T GC-MS). Thirteen compounds were identified with a quality match of 90% and above using GC-MS. The compounds were (1) Cyclohexene, 6-ethenyl-6-methyl-1-(1-methylethyl)-3-(1-methylethylidene)-, (S)-; (2) Bicylo (2.2.1) heptan-2-one, 1, 7, 7-trimethyl-(1S, 4S)-; (3) Phenol, 2-methoxy-4-(1-propenyl)-; (4) Benzene, 1-(1, 5-dimethyl-4-hexenyl)-4-methyl-; (5) Naphthalene, 1, 2, 3, 5, 6, 8a-hexahydro4, 7-dimethyl-1-1-(1-methylethyl)-, (1S-cis)-; (6) Phenol, 2-methoxy-; (7) Benzaldehyde, 3-hydroxy-4-methoxy-; (8) 11, 13-Eicosadienoic acid, methyl ester; (9) 2-Furancarboxaldehyde, 5-methyl-; (10) Maltol; (11) Phenol; (12) Hydroquinone; (13) 1H-Indene, 1-ethylideneoctahydro-7a-methyl-, (1E, 3a.alpha, 7a.beta.). Other compounds (14) 3-methyl butanal; (15) (D)-Limonene; (16) 1-methyl-4-(1-methyl ethyl) benzene; (17) Butanoic acid methyl ester; (18) 2-methyl propanal; (19) 2-butanone; (20) 2-pentanone; and (21) 2-methyl butane were also identified when P&T GC-MS was performed. Of the 21 compounds identified, 12 were validated using chemical standards. The identified compounds were found to be terpenes, derivatives of terpenes, esters, ketones, aldehydes, and phenol-derived aromatic compounds; these are the primary constituents of the essential oils of many plants and flowers. PMID:24804069

  2. Priority of the Mn Deposition Rate in Reactive Evaporation Conditions

    Microsoft Academic Search

    Masaaki Isai; Hiroshi Ichikawa; Takeyoshi Shimada; Keiichiro Morimoto; Hiroshi Fujiyasu; Yasumitsu Ito

    2000-01-01

    Manganese (Mn) oxide films used in lithium secondary batteries were prepared using the reactive evaporation method. One of the problems of using this method is that the manganese evaporant in the crucible suffers oxidation in an oxygen atmosphere. This deteriorates the Mn deposition rate with increasing the deposition run. A separator was introduced in the bottom of the Mn crucible.

  3. A predictive method for volatile organic compounds emission from soil: Evaporation and diffusion behavior investigation of a representative component of crude oil.

    PubMed

    Wang, Haijing; Fischer, Thomas; Wieprecht, Wolfgang; Möller, Detlev

    2015-10-15

    Pipelines are convenient, economical and widely used mode of transportation of crude oil. However, the inevitable or otherwise accidents during such transport of crude oil lead to large scale oil spills, which consequently result in both soil and air pollution. When such pollution occurs, crude oil VOC concentrations in air, soil pollution evaluation and VOC propagation in soil provide important evidence for airborne detection of oils spills. Therefore, several issues, including determination method for VOC, isotherm parameters of VOC sorption on soil surfaces, and VOC diffusion flux simulation, are significant. In our previous study, n-butane and n-pentane were proved to be the maximum VOCs in studied crude oils. Therefore, a predictive method using n-pentane as a representative component is proposed in this paper. Firstly, a headspace solid phase microextraction (SPME) method was developed for determination of n-pentane in non-equilibrium mass transfer conditions. Secondly, Brunauer-Emmett-Teller (BET) analysis with liquid nitrogen was carried out to predict isotherm parameters for n-pentane. Finally, two models were used to predict the emission process. Probably influenced by gas vapor density below and above the soil layer, the experimental data amounted to 74% of the deduced value from the simplified analytical model. However, the free diffusion model fitted well with the experimental results. PMID:26026407

  4. Method of producing a methane rich gas mixture from mine gas

    Microsoft Academic Search

    E. Richter; K. Giessler; K. Knoblauch; W. Korbacher

    1985-01-01

    A pressure-swing adsorption system is used to enrich the methane content of mine gas obtained from bores around mine shafts or galleries from the customary 25 to 45% by volume to a product gas quality of 50% by volume. Using a carbon molecular sieve adsorbent, the adsorption is carried out at 5 to 8 bar and is followed by a

  5. Preliminary Investigation of Tracer Gas Reaeration Method for Shallow Bays 

    E-print Network

    Baker, Sarah H.; Holley, Edward R.

    1987-01-01

    Accurate estimates of surface exchange rates for volatile pollutants in bays are needed to allow predictions of pollutant movement and retention time. The same types of estimates can be used to calculate reaeration rates. The tracer gas technique...

  6. Method of manufacturing aluminum sulfate from flue gas

    Microsoft Academic Search

    Hauser

    1981-01-01

    A continuous process for removing sulfur dioxide from flue gas is described. Sodium aluminate solution is reacted with sulfur dioxide to form sodium sulfite and aluminum hydroxy sulfite. These are separated and the aluminum hydroxy sulfite oxidized to aluminum sulfate.

  7. Method for combined removal of mercury and nitrogen oxides from off-gas streams

    DOEpatents

    Mendelsohn, Marshall H. (Downers Grove, IL); Livengood, C. David (Lockport, IL)

    2006-10-10

    A method for removing elemental Hg and nitric oxide simultaneously from a gas stream is provided whereby the gas stream is reacted with gaseous chlorinated compound to convert the elemental mercury to soluble mercury compounds and the nitric oxide to nitrogen dioxide. The method works to remove either mercury or nitrogen oxide in the absence or presence of each other.

  8. Color of Evaporated Milks

    Microsoft Academic Search

    Byron H. Webb; George E. Holm

    1930-01-01

    Agriculture The color of evaporated milk is of considerable commercial im- portance since it is one of the fundamental characteristics by which the consumer judges the product. Some of the various factors concerned in the production of color are recognized in a general qualitative way by the producer. No data, however, are available dealing with the factors concerned in the

  9. Magnetic trapping and evaporative cooling of Mn

    NASA Astrophysics Data System (ADS)

    Nguyen, Scott V.; Doret, S. Charles; Harris, Jack G. E.; Helton, Joel; Ketterle, Wolfgang; Michniak, Robert; Doyle, John M.

    2004-05-01

    Atomic manganese is, for the first time, magnetically trapped and evaporatively cooled. Loading of the trap is accomplished using a cold helium buffer gas along with an ablation-based atom source. Utilizing a new experimental apparatus that relies on a fast actuating cryogenic valve to rapidly pump out the buffer gas, 10^11 Mn atoms are trapped and thermally isolated. This allows the sample to be cooled further by evaporative cooling. Mn-Mn elastic and inelastic (dipolar relaxation) collisional cross sections are measured at 500 mK and below. In addition, studies of spin exchange in this "submerged shell" S-state atom are investigated. Other recent results will also be presented.

  10. Computation of turbulent evaporating sprays: Eulerian versus Lagrangian approach

    SciTech Connect

    Hallmann, M.; Scheurlen, M.; Wittig, S. [Univ. Karlsruhe (Germany). Lehrstuhl und Inst. fuer Thermische Stroemungsmaschinen

    1995-01-01

    A new Eulerian model for turbulent evaporating sprays is presented. It comprises droplet heating and evaporation processes by solving separate transport equations for the droplet`s temperature and diameter. A Lagrangian approach, which the authors have discussed in detail on other occasions, is used in comparing the results of the new method. A comparison with experimental data shows that both approaches are successful in predicting the main features of turbulent evaporating sprays.

  11. A Gas Chromatographic Method for the Determination of Aldose and Uronic Acid Constituents of Plant Cell Wall Polysaccharides 1

    PubMed Central

    Jones, Thomas M.; Albersheim, Peter

    1972-01-01

    A major problem in determining the composition of plant cell wall polysaccharides has been the lack of a suitable method for accurately determining the amounts of galacturonic and glucuronic acids in such polymers. A gas chromatographic method for aldose analysis has been extended to include uronic acids. Cell wall polysaccharides are depolymerized by acid hydrolysis followed by treatment with a mixture of fungal polysaccharide-degrading enzymes. The aldoses and uronic acids released by this treatment are then reduced with NaBH4 to alditols and aldonic acids, respectively. The aldonic acids are separated from the alditols with Dowex-1 (acetate form) ion exchange resin, which binds the aldonic acids. The alditols, which do not bind, are washed from the resin and then acetylated with acetic anhydride to form the alditol acetate derivatives. The aldonic acids are eluted from the resin with HCl. After the resin has been removed, the HCl solution of the aldonic acids is evaporated to dryness, converting the aldonic acids to aldonolactones. The aldonolactones are reduced with NaBH4 to the corresponding alditols, dried and acetylated. The resulting alditol acetate mixtures produced from the aldoses and those from the uronic acids are analyzed separately by gas chromatography. This technique has been used to determine the changes in composition of Red Kidney bean (Phaseolus vulgaris) hypocotyl cell walls during growth, and to compare the cell wall polysaccharide compositions of several parts of bean plants. Galacturonic acid is found to be a major component of all the cell wall polysaccharides examined. PMID:16658086

  12. High-temperature gas stream filter and method

    SciTech Connect

    Notestein, J.E.

    1994-12-31

    The present invention relates generally to the removal of solid particulate material from high-temperature gas streams, and more particularly the removal of such particulate material by employing a barrier filter formed of a carbon-carbon composite provided by a porous carbon fiber substrate with open interstitial regions between adjacently disposed carbon fibers selectively restricted by carbon integrally attached to the carbon fibers of the substrate. In a typical utilization of a particulate-bearing hot gas stream, the particulate loading of the gas stream after cleaning is normally less than about 50 ppm and with essentially no particulates larger than about 10 microns. This carbon-carbon filter for removing particulate material of a particle size larger than a preselected particle size from a gas stream at a temperature greater than about 800 F, is produced by the steps which comprise: providing a substrate of carbonaceous fibers with pore-forming open interstitial regions between adjacently disposed fibers; and, sufficiently filling these open interstitial regions with carbon integrally attached to and supported by the fibers for providing the interstitial regions with throughgoing passage-ways of a pore size sufficient to provide for the passage of the gas stream while preventing the passage of particulate material larger than a preselected particle size.

  13. Method of recovering energy in the manufacture of polymers from monomeric gas and apparatus for carrying out the method

    SciTech Connect

    Kempf, J.G.

    1981-06-30

    In a method of recovering energy in the manufacture of high pressure polyethylene from ethylene gas, the ethylene gas is compressed and partially converted into polyethylene in a reactor by polymerization. For the purpose of energy recovery, the polymer-gas mixture being discharged from the reactor is accelerated and decompressed in a nozzle system of an energy exchange unit, mixed and compressed with an almost polymer-free working stream. The polymer-free gas is then separated in a separator. The working stream flows through a decompression turbine, and is subsequently conveyed together with the polymer-gas mixture from the reactor into the nozzle system of the energy exchange unit and is continuously re-compressed in the energy exchange unit by the gas stream from the decompression turbine.

  14. Simulations of Evaporating Multicomponent Fuel Drops

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Le Clercq, Patrick

    2005-01-01

    A paper presents additional information on the subject matter of Model of Mixing Layer With Multicomponent Evaporating Drops (NPO-30505), NASA Tech Briefs, Vol. 28, No. 3 (March 2004), page 55. To recapitulate: A mathematical model of a three-dimensional mixing layer laden with evaporating fuel drops composed of many chemical species has been derived. The model is used to perform direct numerical simulations in continuing studies directed toward understanding the behaviors of sprays of liquid petroleum fuels in furnaces, industrial combustors, and engines. The model includes governing equations formulated in an Eulerian and a Lagrangian reference frame for the gas and drops, respectively, and incorporates a concept of continuous thermodynamics, according to which the chemical composition of a fuel is described by use of a distribution function. In this investigation, the distribution function depends solely on the species molar weight. The present paper reiterates the description of the model and discusses further in-depth analysis of the previous results as well as results of additional numerical simulations assessing the effect of the mass loading. The paper reiterates the conclusions reported in the cited previous article, and states some new conclusions. Some new conclusions are: 1. The slower evaporation and the evaporation/ condensation process for multicomponent-fuel drops resulted in a reduced drop-size polydispersity compared to their single-component counterpart. 2. The inhomogeneity in the spatial distribution of the species in the layer increases with the initial mass loading. 3. As evaporation becomes faster, the assumed invariant form of the molecular- weight distribution during evaporation becomes inaccurate.

  15. Method for removing hydrogen sulfide from coke oven gas

    SciTech Connect

    Ritter, H.

    1982-08-03

    An improved sulfur-ammonia process is disclosed for removing hydrogen sulfide from coke oven gases. In the improved process, a concentrator formerly used for standby operation is used at all normal times as an ammonia scrubber to improve the efficiency of gas separation during normal operation and is used as a concentrator for its intended standby functions during the alternative operations. In its normal function, the concentrator/scrubber functions as a scrubber to strip ammonia gas from recirculating liquid streams and to permit introduction of an ammonia-rich gas into a hydrogen sulfide scrubber to increase the separation efficiency of that unit. In the standby operation, the same concentrator/scrubber serves as a concentrator to concentrate hydrogen sulfide in a ''strong liquor'' stream for separate recovery as a strong liquor.

  16. Using the gradient method to measure soil gas fluxes: limitations and pitfalls

    NASA Astrophysics Data System (ADS)

    Martin, Martin; Schack-Kirchner, Helmer

    2015-04-01

    The gradient method (De Jong & Schappert,1974) can be used to determine gas efflux from the soil, representing an alternative to the widely used chamber methods. In addition, valuable information about the vertical distribution of the sources/sinks of gas (e.g. CO2, CH4) in the soil can be derived. Although the method seems to be simple, care must be taken whether all assumption and simplifications are made: (1) Diffusion only: Gas transport can be described by Fick's law. (2) 1D vertical gas diffusion: No horizontal concentration gradients. (3) Gas diffusion in the soil is at steady-state: Changes are negligible. If the preconditions are not met, the gradient method may yield unreliable results. We tried to address some of these and further issues in different studies. We identified the method used to interpolate the gas concentration profile between the measurement locations as an issue affecting substantially the calculated efflux and vertical partitioning. Another critical issue is deriving the correct soil gas diffusivity. The assumption of steady-state diffusion is not always justified, especially after rain, and may lead to substantial misinterpretation if ignored. We also observed that soil gas transport can be affected by turbulence-driven pressure-pumping, so that the effect of non-diffusive gas transport must be considered. The Temporal and spatial resolution must match the research question and gas species. The gradient method is a valuable tool , that, Ideally, the GM should be used on well aerated, horizontally homogeneous soils where gas exchange is entirely driven by diffusion. Here the gradient method promises to yield reliable results when soil respiration and methane consumption is studied. Substantial discrepancy in these conditions could lead to increasing uncertainty in the flux estimates

  17. DWPF Recycle Evaporator Shielded Cells Testing

    SciTech Connect

    Fellinger, T. L.; Herman, D. T.; Stone, M.E

    2005-07-01

    Testing was performed to determine the feasibility and processing characteristics of evaporation of actual Defense Waste Processing Facility (DWPF) recycle material. Samples of the Off Gas Condensate Tank (OGCT) and Slurry Mix Evaporator Condensate Tank (SMECT) were transferred from DWPF to the Savannah River National Lab (SRNL) Shielded Cells and blended with De-Ionized (DI) water and a small amount of Slurry Mix Evaporator (SME) product. A total of 3000 mL of this feed was concentrated to approximately 90 mL during a semi-batch evaporation test of approximately 17 hours. One interruption occurred during the run when the feed tube developed a split and was replaced. Samples of the resulting condensate and concentrate were collected and analyzed. The resulting analysis of the condensate was compared to the Waste Acceptance Criteria (WAC) limits for the F/H Effluent Treatment Plant (ETP). Results from the test were compared to previous testing using simulants and OLI modeling. Conclusions from this work included the following: (1) The evaporation of DWPF recycle to achieve a 30X concentration factor was successfully demonstrated. The feed blend of OGCT and SMECT material was concentrated from 3000 mL to approximately 90 mL during testing, a concentration of approximately 33X. (2) Foaming was observed during the run. Dow Corning 2210 antifoam was added seven times throughout the run at 100 parts per million (ppm) per addition. The addition of this antifoam was very effective in reducing the foam level, but the impact diminished over time and additional antifoam was required every 2 to 3 hours during the run. (3) No scale or solids formed on the evaporator vessel, but splatter was observed in the headspace of the evaporator vessel. No scaling formed on the stainless steel thermocouple. (4) The majority of the analytes met the F/H ETP WAC. However, the detection limits for selected species (Sr-90, Pu-238, Pu-240, Am-243, and Cm-244) exceeded the ETP WAC limits. (5) I-129 was calculated to have exceeded the ETP WAC limits based on an assumed Decontamination Factor (DF) of 1 during evaporation. (6) The DF for most species was limited by the detection limits of the sample analysis. Based on iron, manganese, total alpha, total beta, and other species, very low entrainment was noted and evaporator DF was >10,000 for non-volatile species. (7) Very low DF's were obtained for selected species, especially mercury and formate. These species are present as volatile compounds and will exceed ETP WAC limits if sufficient concentrations are in the evaporator feed. (8) The evaporator DF's for the radioactive test were in good agreement with simulant test results. Differences noted in the DF of selected species, such as Hg, were more likely attributed to analytical issues than differences in the performance of the two evaporators. (9) The simulant appeared to be conservative in terms of foaming and scaling characteristics of the evaporator. The initial spike in foaming that occurred during all simulant runs did not occur during the Shielded Cells run and overall foaminess after the start of the test was controlled by antifoam additions. The splatter that was deposited during the radioactive test was less than the simulant runs and was more easily removed. (10) The OLI model results were overly conservative due to the manner that entrainment of solids was incorporated into the model.

  18. Diffusion NMR methods applied to xenon gas for materials study.

    PubMed

    Mair, R W; Rosen, M S; Wang, R; Cory, D G; Walsworth, R L

    2002-12-01

    We report initial NMR studies of (i) xenon gas diffusion in model heterogeneous porous media and (ii) continuous flow laser-polarized xenon gas. Both areas utilize the pulsed gradient spin-echo (PGSE) techniques in the gas phase, with the aim of obtaining more sophisticated information than just translational self-diffusion coefficients--a brief overview of this area is provided in the Introduction. The heterogeneous or multiple-length scale model porous media consisted of random packs of mixed glass beads of two different sizes. We focus on observing the approach of the time-dependent gas diffusion coefficient, D(t) (an indicator of mean squared displacement), to the long-time asymptote, with the aim of understanding the long-length scale structural information that may be derived from a heterogeneous porous system. We find that D(t) of imbibed xenon gas at short diffusion times is similar for the mixed bead pack and a pack of the smaller sized beads alone, hence reflecting the pore surface area to volume ratio of the smaller bead sample. The approach of D(t) to the long-time limit follows that of a pack of the larger sized beads alone, although the limiting D(t) for the mixed bead pack is lower, reflecting the lower porosity of the sample compared to that of a pack of mono-sized glass beads. The Pade approximation is used to interpolate D(t) data between the short- and long-time limits. Initial studies of continuous flow laser-polarized xenon gas demonstrate velocity-sensitive imaging of much higher flows than can generally be obtained with liquids (20-200 mm s-1). Gas velocity imaging is, however, found to be limited to a resolution of about 1 mm s-1 owing to the high diffusivity of gases compared with liquids. We also present the first gas-phase NMR scattering, or diffusive-diffraction, data, namely flow-enhanced structural features in the echo attenuation data from laser-polarized xenon flowing through a 2 mm glass bead pack. PMID:12807139

  19. Lake Evaporation: a Model Study

    Microsoft Academic Search

    Jumah Ahmad Amayreh

    1995-01-01

    Reliable evaporation data are an essential requirement in any water and\\/or energy budget studies. This includes operation and management of both urban and agricultural water resources. Evaporation from large, open water surfaces such as lakes and reservoirs may influence many agricultural and irrigation decisions. In this study evaporation from Bear Lake in the states of Idaho and Utah was measured

  20. EVAPORATION OF ICY PLANETESIMALS DUE TO BOW SHOCKS

    SciTech Connect

    Tanaka, Kyoko K.; Yamamoto, Tetsuo; Tanaka, Hidekazu [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan)] [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan); Miura, Hitoshi [Department of Earth Sciences, Tohoku University, Sendai 980-8578 (Japan)] [Department of Earth Sciences, Tohoku University, Sendai 980-8578 (Japan); Nagasawa, Makiko; Nakamoto, Taishi [Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551 (Japan)] [Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551 (Japan)

    2013-02-20

    We present the novel concept of evaporation of planetesimals as a result of bow shocks associated with planetesimals orbiting with supersonic velocities relative to the gas in a protoplanetary disk. We evaluate the evaporation rates of the planetesimals based on a simple model describing planetesimal heating and evaporation by the bow shock. We find that icy planetesimals with radius {approx}>100 km evaporate efficiently even outside the snow line in the stage of planetary oligarchic growth, where strong bow shocks are produced by gravitational perturbations from protoplanets. The obtained results suggest that the formation of gas giant planets is suppressed owing to insufficient accretion of icy planetesimals onto the protoplanet within the {approx}<5 AU disk region.

  1. Optimizing the efficiency of evaporative cooling in optical dipole traps

    E-print Network

    Olson, Abraham J; Chen, Yong P

    2013-01-01

    We present a combined computational and experimental study to optimize the efficiency of evaporative cooling for atoms in optical dipole traps. By employing a kinetic model of evaporation, we provide a strategy for determining the optimal relation between atom temperature, trap depth, and average trap frequency during evaporation given experimental initial conditions. We then experimentally implement a highly efficient evaporation process in an optical dipole trap, showing excellent agreement between the theory and experiment. This method has allowed the creation of pure Bose-Einstein condensates of $^{87}$Rb with 2$\\times 10^4$ atoms starting from only $5\\times 10^5$ atoms initially loaded in the optical dipole trap, achieving an evaporation efficiency, $\\gamma_{eff}$, of 4.0 during evaporation.

  2. Evaporation from the free water surface of a flooded forest

    NASA Astrophysics Data System (ADS)

    Newman, A.; Keim, R.; Hiscox, A.

    2011-12-01

    Controls on evaporation rates from the free water surface of flooded forests have received little attention despite being an important component of the water balance in wetlands. In flooded forests, the tree canopy reduces solar radiation and turbulent exchange, so evaporation rates are lower than from an open water body. We measured evaporation from the free water surface in a flooded cypress/tupelo forest in southern Louisiana, USA, using both Bowen-ratio energy balance and eddy covariance methods. We compare results, which to our knowledge comprise the first experimental data set of evaporation rates in a flooded forest, to rates predicted by a simple empirical model.

  3. Preliminary Investigation of Tracer Gas Reaeration Method for Shallow Bays

    E-print Network

    Baker, Sarah H.; Holley, Edward R.

    was used with propane for the tracer gas and Rhodamine-WT, a fluorescent dye, for the "conservative" tracer. The propane was injected through porous tile diffusers, and the dye was released simultaneously. The propane acts as a model for the surface...

  4. Some Methods of Oil and Gas Reserve Estimation in Azerbaijan

    Microsoft Academic Search

    M. T. ABASOV; L. A. BURYAKOVSKY; Y. M. Kondrushkin; R. D. DZHEVANSHIR; T. Y. BAGAROV; G. V. CHILINGAR

    1997-01-01

    This article deals with the scientific and practical problems related to estimating oil and gas reserves in terrigenous reservoirs of the Productive Series of middle Pliocene and in Upper Cretaceous volcanic and sedimentary rocks. The deposits in question are spread over onshore Azerbaijan and adjacent offshore areas in the Caspian Sea and are approximately 6.5 km deep. This article presents

  5. Accuracy of lagoon gas emissions using an inverse dispersion method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measuring gas emissions from treatment lagoons and storage ponds poses challenging conditions for existing micrometeorological techniques because of non-ideal wind conditions. These include those induced by trees and crops surrounding the lagoons, and lagoons with dimensions too small to establish ...

  6. Method and apparatus for controlling gas evolution from chemical reactions

    Microsoft Academic Search

    James R. Skorpik; Michael G. Dodson

    1999-01-01

    The present invention is directed toward monitoring a thermally driven gas evolving chemical reaction with an acoustic apparatus. Signals from the acoustic apparatus are used to control a heater to prevent a run-away condition. A digestion module in combination with a robotic arm further automate physical handling of sample material reaction vessels. The invention is especially useful for carrying out

  7. Gas and oil well pumping or swabbing device and method

    Microsoft Academic Search

    Coyle

    1989-01-01

    This patent describes an elongate gas and oil well pumping or swabbing device for insertion lengthwise within a well casing having a wellhead casing closed by a wellhead cap. It consists of an elongate barrel capped at its bottom and top ends, having an open interior defining an elongate flow passage valve means including a valve seat defined internally of

  8. Gas chromatographic method for direct analysis of photochemically nonreactive hydrocarbons

    Microsoft Academic Search

    F. M. Black; L. E. High; J. E. Sigsby

    1976-01-01

    The Environmental Protection Agency has developed an analytical system for the quantitative determination of methane, ethane, propane, acetylene, and benzene - hydrocarbons that do not contribute to air pollution - in air samples using a multicolumn gas chromatograph. The determination of reactive hydrocarbon emissions is then possible by difference with total hydrocarbon data generally obtained with a flame ionization analyzer.

  9. Apparatus for the liquefaction of natural gas and methods relating to same

    DOEpatents

    Wilding, Bruce M. (Idaho Falls, ID) [Idaho Falls, ID; McKellar, Michael G. (Idaho Falls, ID) [Idaho Falls, ID; Turner, Terry D. (Ammon, ID) [Ammon, ID; Carney, Francis H. (Idaho Falls, ID) [Idaho Falls, ID

    2009-09-29

    An apparatus and method for producing liquefied natural gas. A liquefaction plant may be coupled to a source of unpurified natural gas, such as a natural gas pipeline at a pressure letdown station. A portion of the gas is drawn off and split into a process stream and a cooling stream. The cooling stream passes through an expander creating work output. A compressor may be driven by the work output and compresses the process stream. The compressed process stream is cooled, such as by the expanded cooling stream. The cooled, compressed process stream is divided into first and second portions with the first portion being expanded to liquefy the natural gas. A gas-liquid separator separates the vapor from the liquid natural gas. The second portion of the cooled, compressed process stream is also expanded and used to cool the compressed process stream.

  10. System and method to determine thermophysical properties of a multi-component gas

    DOEpatents

    Morrow, Thomas B.; Behring, II, Kendricks A.

    2003-08-05

    A system and method to characterize natural gas hydrocarbons using a single inferential property, such as standard sound speed, when the concentrations of the diluent gases (e.g., carbon dioxide and nitrogen) are known. The system to determine a thermophysical property of a gas having a first plurality of components comprises a sound velocity measurement device, a concentration measurement device, and a processor to determine a thermophysical property as a function of a correlation between the thermophysical property, the speed of sound, and the concentration measurements, wherein the number of concentration measurements is less than the number of components in the gas. The method includes the steps of determining the speed of sound in the gas, determining a plurality of gas component concentrations in the gas, and determining the thermophysical property as a function of a correlation between the thermophysical property, the speed of sound, and the plurality of concentrations.

  11. Partial discharge diagnosis method using electromagnetic wave mode transformation in gas insulated switchgear

    Microsoft Academic Search

    Shigemitsu Okabe; Shuhei Kaneko; Manabu Yoshimura; Hirotaka Muto; Chieko Nishida; Mitsuhito Kamei

    2007-01-01

    Though the gas insulated switchgear (GIS) insulation diagnosis method using ultra high frequency (UHF) band signal is widely used as a method to detect partial discharge (PD) sensitively, diagnosis methods for the electromagnetic wave mode propagation behavior in GIS tanks have not been investigated enough. Especially, diagnosis methods based on the electromagnetic wave distribution of the circumferential direction have been

  12. Assessment of water droplet evaporation mechanisms on hydrophobic and superhydrophobic substrates.

    PubMed

    Pan, Zhenhai; Dash, Susmita; Weibel, Justin A; Garimella, Suresh V

    2013-12-23

    Evaporation rates are predicted and important transport mechanisms identified for evaporation of water droplets on hydrophobic (contact angle ~110°) and superhydrophobic (contact angle ~160°) substrates. Analytical models for droplet evaporation in the literature are usually simplified to include only vapor diffusion in the gas domain, and the system is assumed to be isothermal. In the comprehensive model developed in this study, evaporative cooling of the interface is accounted for, and vapor concentration is coupled to local temperature at the interface. Conjugate heat and mass transfer are solved in the solid substrate, liquid droplet, and surrounding gas. Buoyancy-driven convective flows in the droplet and vapor domains are also simulated. The influences of evaporative cooling and convection on the evaporation characteristics are determined quantitatively. The liquid-vapor interface temperature drop induced by evaporative cooling suppresses evaporation, while gas-phase natural convection acts to enhance evaporation. While the effects of these competing transport mechanisms are observed to counterbalance for evaporation on a hydrophobic surface, the stronger influence of evaporative cooling on a superhydrophobic surface accounts for an overprediction of experimental evaporation rates by ~20% with vapor diffusion-based models. The local evaporation fluxes along the liquid-vapor interface for both hydrophobic and superhydrophobic substrates are investigated. The highest local evaporation flux occurs at the three-phase contact line region due to proximity to the higher temperature substrate, rather than at the relatively colder droplet top; vapor diffusion-based models predict the opposite. The numerically calculated evaporation rates agree with experimental results to within 2% for superhydrophobic substrates and 3% for hydrophobic substrates. The large deviations between past analytical models and the experimental data are therefore reconciled with the comprehensive model developed here. PMID:24320680

  13. Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Almlie, Jay C.

    2010-01-01

    A water membrane evaporator (WME) has been conceived and tested as an alternative to the contamination-sensitive and corrosion-prone evaporators currently used for dissipating heat from space vehicles. The WME consists mainly of the following components: An outer stainless-steel screen that provides structural support for the components mentioned next; Inside and in contact with the stainless-steel screen, a hydrophobic membrane that is permeable to water vapor; Inside and in contact with the hydrophobic membrane, a hydrophilic membrane that transports the liquid feedwater to the inner surface of the hydrophobic membrane; Inside and in contact with the hydrophilic membrane, an annular array of tubes through which flows the spacecraft coolant carrying the heat to be dissipated; and An inner exclusion tube that limits the volume of feedwater in the WME. In operation, a pressurized feedwater reservoir is connected to the volume between the exclusion tube and the coolant tubes. Feedwater fills the volume, saturates the hydrophilic membrane, and is retained by the hydrophobic membrane. The outside of the WME is exposed to space vacuum. Heat from the spacecraft coolant is conducted through the tube walls and the water-saturated hydrophilic membrane to the liquid/vapor interface at the hydrophobic membrane, causing water to evaporate to space. Makeup water flows into the hydrophilic membrane through gaps between the coolant tubes.

  14. Evaporative cooling of the dipolar radical OH

    E-print Network

    Benjamin K. Stuhl; Matthew T. Hummon; Mark Yeo; Goulven Quéméner; John L. Bohn; Jun Ye

    2012-09-27

    Atomic physics was revolutionized by the development of forced evaporative cooling: it led directly to the observation of Bose-Einstein condensation, quantum-degenerate Fermi gases, and ultracold optical lattice simulations of condensed matter phenomena. More recently, great progress has been made in the production of cold molecular gases, whose permanent electric dipole moment is expected to generate rich, novel, and controllable phases, dynamics, and chemistry in these ultracold systems. However, while many strides have been made in both direct cooling and cold-association techniques, evaporative cooling has not yet been achieved due to unfavorable elastic-to-inelastic ratios and impractically slow thermalization rates in the available trapped species. We now report the observation of microwave-forced evaporative cooling of hydroxyl (OH) molecules loaded from a Stark-decelerated beam into an extremely high-gradient magnetic quadrupole trap. We demonstrate cooling by at least an order of magnitude in temperature and three orders in phase-space density, limited only by the low-temperature sensitivity of our spectroscopic thermometry technique. With evaporative cooling and sufficiently large initial populations, much colder temperatures are possible, and even a quantum-degenerate gas of this dipolar radical -- or anything else it can sympathetically cool -- may now be in reach.

  15. Are electro-kinetic methods useful in the development of tight gas and shale gas resources?

    NASA Astrophysics Data System (ADS)

    Glover, Paul W. J.

    2013-04-01

    The development of unconventional reservoirs provides new challenges to the petrophysicist; challenges that might be overcome with new techniques and approaches. The application of electro-kinetics to hydrocarbon reservoirs is relatively recent. In fact, up until 2012 there was no theoretical model that was capable of predicting the streaming potential coefficient of a rock with given petrophysical properties (Glover et al., 2012). Here, we use that model to ask the question whether the measurement of electro-kinetic properties of tight gas sands and gas shales could be useful in the development of these resources. We have calculated the streaming potential coefficient for gas shales with typical values of porosity, cementation exponent and grain size as a function of pore fluid salinity (10-5 to 2 mol/dm3) and pH (pH 5-9) at the temperatures and pressures encountered in shale gas reservoirs. For typical gas shales such as the Barnett shale (grain diameter 0.1 ? m, porosity 2.5 % and 5 ? D, respectively) the streaming potential coefficient is less than 2×10-10 V/Pa for all the modelled salinities and pHs. This is extremely small, and would only result in a streaming potential of the order of millivolts even during hydraulic fracturing at 10 kpsi, while deep monitoring of fluid flow would be impossible. Similar modelling of typical tight gas sands (grain diameter 3 ? m, porosity 5 %, permeability 0.1 mD) provides a higher streaming potential coefficients, reaching 10-7 V/Pa at low salinities (

  16. Optical methods and systems for detecting a constituent in a gas containing oxygen in harsh environments

    DOEpatents

    Carpenter, Michael A. (Scotia, NY); Sirinakis, George (Bronx, NY)

    2011-01-04

    A method for detecting a gas phase constituent such as carbon monoxide, nitrogen dioxide, hydrogen, or hydrocarbons in a gas comprising oxygen such as air, includes providing a sensing material or film having a metal embedded in a catalytically active matrix such as gold embedded in a yttria stabilized zirconia (YSZ) matrix. The method may include annealing the sensing material at about 900.degree. C., exposing the sensing material and gas to a temperature above 400.degree. C., projecting light onto the sensing material, and detecting a change in the absorption spectrum of the sensing material due to the exposure of the sensing material to the gas in air at the temperature which causes a chemical reaction in the sensing material compared to the absorption spectrum of the sensing material in the absence of the gas. Systems employing such a method are also disclosed.

  17. Good odorant practices ensure safer operations. [Natural gas odorant detection methods

    SciTech Connect

    Oudman, P. (Canada Western Natural Gas Co. Ltd., Calgary, Alberta (Canada))

    1993-12-01

    Regulations in Canada and the US require that combustible gas used as a fuel be odorized at such a level that a concentration in air of one-fifth the lower explosive limit the gas can be readily detected and recognized by a person with a normal sense of smell. These regulations do not specify how the odorant level should be determined. However, since the requirement is related to smell, the level should be determined by an olfactory method. There are two odorant monitoring methods commonly used by gas companies, the olfactory (odorometer) and the instrumentation (gas chromatograph) methods. The instrument method provides only quantitative results, which somehow must be related to an olfactory response. This paper discusses these methods.

  18. Normal evaporation of binary alloys

    NASA Technical Reports Server (NTRS)

    Li, C. H.

    1972-01-01

    In the study of normal evaporation, it is assumed that the evaporating alloy is homogeneous, that the vapor is instantly removed, and that the alloy follows Raoult's law. The differential equation of normal evaporation relating the evaporating time to the final solute concentration is given and solved for several important special cases. Uses of the derived equations are exemplified with a Ni-Al alloy and some binary iron alloys. The accuracy of the predicted results are checked by analyses of actual experimental data on Fe-Ni and Ni-Cr alloys evaporated at 1600 C, and also on the vacuum purification of beryllium. These analyses suggest that the normal evaporation equations presented here give satisfactory results that are accurate to within an order of magnitude of the correct values, even for some highly concentrated solutions. Limited diffusion and the resultant surface solute depletion or enrichment appear important in the extension of this normal evaporation approach.

  19. A molecular dynamics simulation of droplet evaporation Lorenzo Consolini 1

    E-print Network

    Aggarwal, Suresh K.

    A molecular dynamics simulation of droplet evaporation Lorenzo Consolini 1 , Suresh K. Aggarwal A molecular dynamics (MD) simulation method is developed to study the evaporation of submicron droplets the ``vaporization'' process. Ó 2003 Elsevier Science Ltd. All rights reserved. Keywords: Molecular dynamics

  20. Evaporative cooling feature selection for genotypic data involving interactions

    Microsoft Academic Search

    B. A. Mckinney; David M. Reif; Bill C. White; J. E. Crowe Jr.; Jason H. Moore

    2007-01-01

    Motivation: The development of genome-wide capabilities for genotyping has led to the practical problem of identifying the minimum subset of genetic variants relevant to the classification of a phenotype. This challenge is especially difficult in the presence of attribute interactions, noise and small sample size. Methods: Analogous to the physical mechanism of evaporation, we introduce an evaporative cooling (EC) feature

  1. Analysis of a geopressured gas reservoir using solution plot method

    E-print Network

    Hussain, Syed Muqeedul

    1992-01-01

    dependent formation compressibility and water influx require extensive study of the reservoir core samples and aquifer characteristics that are not commonly conducted. Poston and Chen solved this problem by re-arranging the material balance equation... such that the input variables are the readily available pressure and production data. The output of the resulting plot, known as the Solution plot, is the original gas in place, effective compressibility and possibly water influx history. The early time data from a...

  2. A systematic method for validation of gas exchange measurements.

    PubMed

    Damask, M C; Weissman, C; Askanazi, J; Hyman, A I; Rosenbaum, S H; Kinney, J M

    1982-09-01

    The measurement of gas exchange is useful, but thus far, has not been practical during the mechanical ventilation of critically ill patients. To validate two new commercial instruments, (Siemens-Elema Servo Ventilator 900B, Beckman Metabolic Cart), the authors constructed a lung model into which they delivered CO2 and N2 at precise rates to simulate Co2 production (Vco2) and O2 consumption (Vos). The model consists of 13.5-1 gas jar with an attached one liter anesthesia bag. The lung model was ventilated at present tidal volumes and frequencies. The authors also compared the measured respiratory quotient (RQ) with the known RQ of burning methanol (RQ = 0.67) in the jar. When the model was ventilated with levels of tidal volume and gas exchange applicable to adults, both instruments measured V02 within 5 to 13% of predicted values. Varying the FI02 did not significantly affect this accuracy. At tidal volumes below 350 ml, the difference increased between predicted VCO2 and measured VCO2. The difference between measured vs. the actual RQ of methanol was 5 and 1.5% in the Siemens-Elema and Beckman Systems, respectively. PMID:6810731

  3. Method for recovering and utilizing heat of coke-oven gas

    Microsoft Academic Search

    K. Kunioka; H. Nishio; Y. Okuyama; T. Shimotsuma

    1981-01-01

    A method is described for recovering and utilizing heat of coke- oven gas is eliminated. Through heat exchange with a high-temperature coke-oven gas generated from a coke oven battery and containing vaporized coal tar, vaporized low boiling point substances and dust. By drying and preheating a blended raw material coal fine to be charged into coking ovens of said coke

  4. A method to estimate gas magnification of multi-gap resistive plate chamber

    Microsoft Academic Search

    Yuelei WU; Huasi HU; Juan QIN; Xiaolian WANG; Xiangyang ZHENG; Zizong XU

    2007-01-01

    The gas magnification of multi-gap resistive plate chamber (MRPC) is very difficult to be measured using the present instruments thoroughly in the world. The gas magnifications about ?107 were obtained in the various operation-high-voltages of multi-gap resistive plate chamber (MRPC) by means of Monte-Carlo simulation and the presented experiment method.

  5. Optical-physical methods of remote diagnostics of high-temperature gas media

    NASA Astrophysics Data System (ADS)

    Voitsekhovskaya, O. K.; Voitsekhovskii, A. V.; Egorov, O. V.; Kashirskii, D. E.

    2014-11-01

    Review of the authors' works devoted to research of properties of high-temperature gas mixtures and advancement of methods of a remote diagnosis of their optical and physical characteristics is presented. Results of the formation of the informational resource on mathematical, spectroscopic, software and hardware support of passive and active remote sensing techniques of gas-aerosol media are discussed.

  6. Method of modal mass analysis of exhaust gas from a motor vehicle

    Microsoft Academic Search

    H. Mikasa; H. Kitamura

    1988-01-01

    A method of measuring the quantity of an ingredient gas in the exhaust gas from a motor vehicle during the time period of each of a sequence of driving modes, the time period of each driving mode having a starting time and an ending time, the ending time of the time period of each driving mode being the starting time

  7. Explosion risk analysis - Development of a general method for gas dispersion analyses on offshore platforms

    Microsoft Academic Search

    Asmund Huser; Oddmund Kvernvold

    A general method to determine the probabilistic distribution of gas cloud sizes from accidental gas leaks on offshore installations has been developed. The main motivations for this development have been to improve accuracy and to reduce the analysis time for new explosion risk analyses. This has been achieved by performing the present very detailed analysis once and for all. Results

  8. Method and apparatus for natural gas and thermal energy production from aquifers

    Microsoft Academic Search

    1982-01-01

    A novel method for producing methane from geopressured aquifers offers advantages over other techniques: 1) the natural gas is produced water-free at the wellhead, 2) less heat is lost during exsolution and expansion of natural gas in the water as it rises in the wellbore and passes through turbines and heat exchangers at the land surface, 3) most of the

  9. Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters. Final report, August 1992August 1996

    Microsoft Academic Search

    J. E. Boysen; K. L. Walker; J. L. Mefford; J. R. Kirsch; J. A. Harju

    1996-01-01

    The use of freeze-crystallization is becoming increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions where subfreezing temperatures seasonally occur. The climates typical of Colorado`s San Juan Basin and eastern slope, as well as the oil

  10. Dynamics of Water Absorption and Evaporation During Methanol Droplet Combustion in Microgravity

    NASA Technical Reports Server (NTRS)

    Hicks, Michael C.; Dietrich, Daniel L.; Nayagam, Vedha; Williams, Forman A.

    2012-01-01

    The combustion of methanol droplets is profoundly influenced by the absorption and evaporation of water, generated in the gas phase as a part of the combustion products. Initially there is a water-absorption period of combustion during which the latent heat of condensation of water vapor, released into the droplet, enhances its burning rate, whereas later there is a water-evaporation period, during which the water vapor reduces the flame temperature suffciently to extinguish the flame. Recent methanol droplet-combustion experiments in ambient environments diluted with carbon dioxide, conducted in the Combustion Integrated Rack on the International Space Station (ISS), as a part of the FLEX project, provided a method to delineate the water-absorption period from the water-evaporation period using video images of flame intensity. These were obtained using an ultra-violet camera that captures the OH* radical emission at 310 nm wavelength and a color camera that captures visible flame emission. These results are compared with results of ground-based tests in the Zero Gravity Facility at the NASA Glenn Research Center which employed smaller droplets in argon-diluted environments. A simplified theoretical model developed earlier correlates the transition time at which water absorption ends and evaporation starts. The model results are shown to agree reasonably well with experiment.

  11. Method for removal of mercury from various gas streams

    DOEpatents

    Granite, E.J.; Pennline, H.W.

    2003-06-10

    The invention provides for a method for removing elemental mercury from a fluid, the method comprising irradiating the mercury with light having a wavelength of approximately 254 nm. The method is implemented in situ at various fuel combustion locations such as power plants and municipal incinerators.

  12. Nonlinear effects of salt concentrations on evaporation from porous media

    NASA Astrophysics Data System (ADS)

    Norouzi Rad, Mansoureh; Shokri, Nima

    2012-02-01

    Evaporation from porous media saturated with salt solution is influenced by the interactions among the transport properties of porous media, thermodynamics of the evaporating solution and environmental conditions. To study the effects of salt concentrations on the evaporation dynamics, we conducted a series of evaporation experiments under constant atmospheric conditions using columns packed with sand particles saturated with various NaCl solutions differing in concentrations. Results show that the evaporation rate decreases as NaCl concentration increases only up to a certain level. When exceeding this level, any further increase of NaCl concentration results in higher evaporation rates which is described theoretically using the thermodynamics of the solution. Results also reveal a nonlinear relation between NaCl concentrations and onset of efflorescence which is described by the numerical solution of the classical convection-diffusion equation. Moreover, we found a strong correlation between the growth dynamics of precipitated salt at the surface and the evaporation rate such that the maximum rate of surface coverage by salt coincide with the end of stage-1 evaporation. This potentially offers a new method to nondestructively study the evaporation process from saline porous media.

  13. Method for generating a highly reactive plasma for exhaust gas after treatment and enhanced catalyst reactivity

    SciTech Connect

    Whealton, John H.; Hanson, Gregory R.; Storey, John M.; Raridon, Richard J.; Armfield, Jeffrey S.; Bigelow, Timothy S.; Graves, Ronald L.

    2000-07-01

    This patent application describes a method and apparatus of exhaust gas remediation that enhance the reactivity of the material catalysts found within catalytic converters of cars, trucks, and power stations.

  14. An Advisory System For Selecting Drilling Technologies and Methods in Tight Gas Reservoirs

    E-print Network

    Pilisi, Nicolas

    2010-01-16

    been collected and documented within the industry literature. The main objective of this research project is to develop a computer program dedicated to applying the drilling technologies and methods selection for drilling tight gas sandstone formations...

  15. Method for converting hydrocarbon fuel into hydrogen gas and carbon dioxide

    DOEpatents

    Clawson, Lawrence G. (Dover, MA); Mitchell, William L. (Belmont, MA); Bentley, Jeffrey M. (Westford, MA); Thijssen, Johannes H. J. (Cambridge, MA)

    2000-01-01

    A method for converting hydrocarbon fuel into hydrogen gas and carbon dioxide within a reformer 10 is disclosed. According to the method, a stream including an oxygen-containing gas is directed adjacent to a first vessel 18 and the oxygen-containing gas is heated. A stream including unburned fuel is introduced into the oxygen-containing gas stream to form a mixture including oxygen-containing gas and fuel. The mixture of oxygen-containing gas and unburned fuel is directed tangentially into a partial oxidation reaction zone 24 within the first vessel 18. The mixture of oxygen-containing gas and fuel is further directed through the partial oxidation reaction zone 24 to produce a heated reformate stream including hydrogen gas and carbon monoxide. Steam may also be mixed with the oxygen-containing gas and fuel, and the reformate stream from the partial oxidation reaction zone 24 directed into a steam reforming zone 26. High- and low-temperature shift reaction zones 64,76 may be employed for further fuel processing.

  16. Highly transparent and conductive ZnO:Al thin films prepared by vacuum arc plasma evaporation

    NASA Astrophysics Data System (ADS)

    Miyata, Toshihiro; Minamino, Youhei; Ida, Satoshi; Minami, Tadatsugu

    2004-07-01

    A vacuum arc plasma evaporation (VAPE) method using both oxide fragments and gas sources as the source materials is demonstrated to be very effective for the preparation of multicomponent oxide thin films. Highly transparent and conductive Al-doped ZnO (AZO) thin films were prepared by the VAPE method using a ZnO fragment target and a gas source Al dopant, aluminum acethylacetonate (Al(C5H7O2)3) contained in a stainless steel vessel. The Al content in the AZO films was altered by controlling the partial pressure (or flow rate) of the Al dopant gas. High deposition rates as well as uniform distributions of resistivity and thickness on the substrate surface were obtained on large area glass substrates. A low resistivity on the order of 10-4 ? cm and an average transmittance above 80% in the visible range were obtained in AZO thin films deposited on glass substrates. .

  17. Numerical Solving Method for the Structural Stiffness of Gas Foil Bearings

    Microsoft Academic Search

    Geng Haipeng; Qi Shemiao; Yu Lie

    \\u000a In order to analyze the performance of Gas Foil Bearings, a coupled finite element method (FEM) is developed in this paper.\\u000a The compressible gas lubricated Reynolds equation is transformed into a typical elliptic partial differential equation and\\u000a solved by FEM. The elastic deformation equation and the contact boundary conditions between foils are solved by nonlinear\\u000a contact finite method. A generalized

  18. A rapid gas chromatographic method for the determination of poly- ? -hydroxybutyric acid in microbial biomass

    Microsoft Academic Search

    G. Braunegg; B. Sonnleitner; R. M. Lafferty

    1978-01-01

    The gas chromatographic method for the determination of poly-ß-hydroxybutyric acid (PHB) consists of a mild acid or alkaline methanolysis of poly-ß-hydroxybutyric acid directly without previous extraction of PHB from the cells; this is followed by gas chromatography of the 3-hydroxybutyric acid methylester. The method is characterized by high accuracy and excellent reproducibility, permitting determinations as low as 10-5 g\\/l. Only

  19. Method of fabricating an integral gas seal for fuel cell gas distribution assemblies

    DOEpatents

    Dettling, Charles J. (E. Hanover, NJ); Terry, Peter L. (Chathum, NJ)

    1988-03-22

    A porous gas distribution plate assembly for a fuel cell, such as a bipolar assembly, includes an inner impervious region wherein the bipolar assembly has good surface porosity but no through-plane porosity and wherein electrical conductivity through the impervious region is maintained. A hot-pressing process for forming the bipolar assembly includes placing a layer of thermoplastic sealant material between a pair of porous, electrically conductive plates, applying pressure to the assembly at elevated temperature, and allowing the assembly to cool before removing the pressure whereby the layer of sealant material is melted and diffused into the porous plates to form an impervious bond along a common interface between the plates holding the porous plates together. The distribution of sealant within the pores along the surface of the plates provides an effective barrier at their common interface against through-plane transmission of gas.

  20. Integral gas seal for fuel cell gas distribution assemblies and method of fabrication

    DOEpatents

    Dettling, Charles J. (E. Hanover, NJ); Terry, Peter L. (Chatham Township, Morris County, NJ)

    1985-03-19

    A porous gas distribution plate assembly for a fuel cell, such as a bipolar assembly, includes an inner impervious region wherein the bipolar assembly has good surface porosity but no through-plane porosity and wherein electrical conductivity through the impervious region is maintained. A hot-pressing process for forming the bipolar assembly includes placing a layer of thermoplastic sealant material between a pair of porous, electrically conductive plates, applying pressure to the assembly at elevated temperature, and allowing the assembly to cool before removing the pressure whereby the layer of sealant material is melted and diffused into the porous plates to form an impervious bond along a common interface between the plates holding the porous plates together. The distribution of sealant within the pores along the surface of the plates provides an effective barrier at their common interface against through-plane transmission of gas.

  1. Methods for Handling Drilled Gas in Oil-Based Drilling Fluids

    Microsoft Academic Search

    P. L. OBryan; A. T. Bourgoyne

    1989-01-01

    This paper presents calculation methods for predicting the behavior of drilled-gas contamination of oil-based drilling fluids. The methods are verified by experiments conducted in a 6,000-ft (1828.8 m) test well. This paper also presents field-handling procedures developed with the calculation methods.

  2. Information Preservation (IP) Method in Simulation of Internal Rarefied Gas Flows in MEMS

    Microsoft Academic Search

    Ching Shen

    2005-01-01

    This paper reviews firstly methods for treating low speed rarefied gas flows: the linearised Boltzmann equation, the Lattice Boltzmann method (LBM), the Navier-Stokes equation plus slip boundary conditions and the DSMC method, and discusses the difficulties in simulating low speed transitional MEMS flows, especially the internal flows. In particular, the present version of the LBM is shown unfeasible for simulation

  3. A new in-situ method to determine the apparent gas diffusion coefficient of soils

    NASA Astrophysics Data System (ADS)

    Laemmel, Thomas; Paulus, Sinikka; Schack-Kirchner, Helmer; Maier, Martin

    2015-04-01

    Soil aeration is an important factor for the biological activity in the soil and soil respiration. Generally, gas exchange between soil and atmosphere is assumed to be governed by diffusion and Fick's Law is used to describe the fluxes in the soil. The "apparent soil gas diffusion coefficient" represents the proportional factor between the flux and the gas concentration gradient in the soil and reflects the ability of the soil to "transport passively" gases through the soil. One common way to determine this coefficient is to take core samples in the field and determine it in the lab. Unfortunately this method is destructive and needs laborious field work and can only reflect a small fraction of the whole soil. As a consequence insecurity about the resulting effective diffusivity on the profile scale must remain. We developed a new in-situ method using new gas sampling device, tracer gas and inverse soil gas modelling. The gas sampling device contains several sampling depths and can be easily installed into vertical holes of an auger, which allows for fast installation of the system. At the lower end of the device inert tracer gas is injected continuously. The tracer gas diffuses into the surrounding soil. The resulting distribution of the tracer gas concentrations is used to deduce the diffusivity profile of the soil. For Finite Element Modeling of the gas sampling device/soil system the program COMSOL is used. We will present the results of a field campaign comparing the new in-situ method with lab measurements on soil cores. The new sampling pole has several interesting advantages: it can be used in-situ and over a long time; so it allows following modifications of diffusion coefficients in interaction with rain but also vegetation cycle and wind.

  4. A versatile method for preparation of hydrated microbial-latex biocatalytic coatings for gas absorption and gas evolution.

    PubMed

    Gosse, Jimmy L; Chinn, Mari S; Grunden, Amy M; Bernal, Oscar I; Jenkins, Jessica S; Yeager, Chris; Kosourov, Sergey; Seibert, Michael; Flickinger, Michael C

    2012-09-01

    We describe a latex wet coalescence method for gas-phase immobilization of microorganisms on paper which does not require drying for adhesion. This method reduces drying stresses to the microbes. It is applicable for microorganisms that do not tolerate desiccation stress during latex drying even in the presence of carbohydrates. Small surface area, 10-65 ?m thick coatings were generated on chromatography paper strips and placed in the head-space of vertical sealed tubes containing liquid to hydrate the paper. These gas-phase microbial coatings hydrated by liquid in the paper pore space demonstrated absorption or evolution of H?, CO, CO? or O?. The microbial products produced, ethanol and acetate, diffuse into the hydrated paper pores and accumulate in the liquid at the bottom of the tube. The paper provides hydration to the back side of the coating and also separates the biocatalyst from the products. Coating reactivity was demonstrated for Chlamydomonas reinhardtii CC124, which consumed CO? and produced 10.2 ± 0.2 mmol O? m?² h?¹, Rhodopseudomonas palustris CGA009, which consumed acetate and produced 0.47 ± 0.04 mmol H? m?² h?¹, Clostridium ljungdahlii OTA1, which consumed 6 mmol CO m?² h?¹, and Synechococcus sp. PCC7002, which consumed CO? and produced 5.00 ± 0.25 mmol O? m?² h?¹. Coating thickness and microstructure were related to microbe size as determined by digital micrometry, profilometry, and confocal microscopy. The immobilization of different microorganisms in thin adhesive films in the gas phase demonstrates the utility of this method for evaluating genetically optimized microorganisms for gas absorption and gas evolution. PMID:22592947

  5. Absolute evaporation rates of non-rotating neutral PAH clusters

    E-print Network

    Montillaud, Julien

    2014-01-01

    Clusters of polycyclic aromatic hydrocarbons (PAHs) have been proposed as candidates for evaporating very small grains, which are thought to be precursors of free-flying PAHs. Evaporation rates have been calculated so far only for species containing up to a few 100 C atoms, whereas interstellar PAH clusters could contain up to ~1000 C atoms. We present a method that generalises the calculation of the statistical evaporation rate of large PAH clusters and provides rates for species containing up to ~1000 C-atoms. The evaporation of non-rotating neutral homo-molecular PAH clusters containing up to 12 molecules from a family of highly symmetric compact PAHs is studied. Statistical calculations were performed and completed with molecular dynamics simulations at high internal energies to provide absolute values for the evaporation rate and distributions of kinetic energy released. The calculations used explicit atom-atom Lennard-Jones potentials in the rigid molecule approximation. A new method is proposed to take...

  6. Thermoelectric integrated membrane evaporation water recovery technology

    NASA Technical Reports Server (NTRS)

    Roebelen, G. J., Jr.; Winkler, H. E.; Dehner, G. F.

    1982-01-01

    The recently developed Thermoelectric Integrated Membrane Evaporation Subsystem (TIMES) offers a highly competitive approach to water recovery from waste fluids for future on-orbit stations such as the Space Operations Center. Low power, compactness and gravity insensitive operation are featured in this vacuum distillation subsystem that combines a hollow fiber membrane evaporator with a thermoelectric heat pump. The hollow fiber elements provide positive liquid/gas phase control with no moving parts other than pumps and an accumulator, thus solving problems inherent in other reclamation subsystem designs. In an extensive test program, over 850 hours of operation were accumulated during which time high quality product water was recovered from both urine and wash water at an average steady state production rate of 2.2 pounds per hour.

  7. Gas turbine nozzle vane insert and methods of installation

    DOEpatents

    Miller, William John (Simpsonville, SC); Predmore, Daniel Ross (Clifton Park, NY); Placko, James Michael (West Chester, OH)

    2002-01-01

    A pair of hollow elongated insert bodies are disposed in one or more of the nozzle vane cavities of a nozzle stage of a gas turbine. Each insert body has an outer wall portion with apertures for impingement-cooling of nozzle wall portions in registration with the outer wall portion. The insert bodies are installed into the cavity separately and spreaders flex the bodies toward and to engage standoffs against wall portions of the nozzle whereby the designed impingement gap between the outer wall portions of the insert bodies and the nozzle wall portions is achieved. The spreaders are secured to the inner wall portions of the insert bodies and the bodies are secured to one another and to the nozzle vane by welding or brazing.

  8. Acoustic device and method for measuring gas densities

    NASA Technical Reports Server (NTRS)

    Shakkottai, Parthasarathy (inventor); Kwack, Eug Y. (inventor); Back, Lloyd (inventor)

    1992-01-01

    Density measurements can be made in a gas contained in a flow through enclosure by measuring the sound pressure level at a receiver or microphone located near a dipole sound source which is driven at constant velocity amplitude at low frequencies. Analytical results, which are provided in terms of geometrical parameters, wave numbers, and sound source type for systems of this invention, agree well with published data. The relatively simple designs feature a transmitter transducer at the closed end of a small tube and a receiver transducer on the circumference of the small tube located a small distance away from the transmitter. The transmitter should be a dipole operated at low frequency with the kL value preferable less that about 0.3.

  9. Reservoir evaporation in Texas, USA

    NASA Astrophysics Data System (ADS)

    Wurbs, Ralph A.; Ayala, Rolando A.

    2014-03-01

    The role of reservoir surface evaporation in river/reservoir water budgets and water management is explored using a modeling system that combines historical natural hydrology with current conditions of water resources development and management. The long-term mean evaporation from the 3415 reservoirs in the Texas water rights permit system is estimated to be 7.53 billion m3/year, which is equivalent to 61% of total agricultural or 126% of total municipal water use in the state during the year 2010. Evaporation varies with the hydrologic conditions governing reservoir surface areas and evaporation rates. Annual statewide total evaporation volumes associated with exceedance probabilities of 75%, 50%, and 25% are 7.07, 7.47, and 7.95 billion m3/year, respectively. Impacts of evaporation are greatest during extended severe droughts that govern water supply capabilities.

  10. Methods of Gas Phase Capture of Iodine from Fuel Reprocessing Off-Gas: A Literature Survey

    SciTech Connect

    Daryl Haefner

    2007-02-01

    A literature survey was conducted to collect information and summarize the methods available to capture iodine from fuel reprocessing off-gases. Techniques were categorized as either wet scrubbing or solid adsorbent methods, and each method was generally described as it might be used under reprocessing conditions. Decontamination factors are quoted only to give a rough indication of the effectiveness of the method. No attempt is made to identify a preferred capture method at this time, although activities are proposed that would provide a consistent baseline that would aid in evaluating technologies.

  11. Representative shuttle evaporative heat sink

    NASA Technical Reports Server (NTRS)

    Hixon, C. W.

    1978-01-01

    The design, fabrication, and testing of a representative shuttle evaporative heat sink (RSEHS) system which vaporizes an expendable fluid to provide cooling for the shuttle heat transport fluid loop is reported. The optimized RSEHS minimum weight design meets or exceeds the shuttle flash evaporator system requirements. A cold trap which cryo-pumps flash evaporator exhaust water from the CSD vacuum chamber test facility to prevent water contamination of the chamber pumping equipment is also described.

  12. Long term measurement of lake evaporation using a pontoon mounted Eddy Covariance system

    NASA Astrophysics Data System (ADS)

    McGowan, H. A.; McGloin, R.; McJannet, D.; Burn, S.

    2011-12-01

    Accurate quantification of evaporation from water storages is essential for design of water management and allocation policy that aims to balance demands for water without compromising the sustainability of future water resources, particularly during periods of prolonged and severe drought. Precise measurement of evaporation from lakes and dams however, presents significant research challenges. These include design and installation of measurement platforms that can withstand a range of wind and wave conditions; accurate determination of the evaporation measurement footprint and the influence of changing water levels. In this paper we present results from a two year long deployment of a pontoon mounted Eddy Covariance (EC) system on a 17.2ha irrigation reservoir in southeast Queensland, Australia. The EC unit included a CSAT-3 sonic anemometer (Campbell Scientific, Utah, United States) and a Li-Cor CS7500 open-path H2O/CO2 infrared gas analyzer (LiCor, Nebraska, United States) at a height of 2.2m, a net radiometer (CNR1, Kipp & Zonen, Netherlands) at a height of 1.2m and a humidity and temperature probe (HMP45C,Vaisala, Finland) at 2.3m. The EC unit was controlled by a Campbell Scientific CR3000 data logger with flux measurements made at 10 Hz and block averaged values logged every 15 minutes. Power to the EC system was from mounted solar panels that charged deep cycle lead-acid batteries while communication was via a cellphone data link. The pontoon was fitted with a weighted central beam and gimbal ring system that allowed self-levelling of the instrumentation and minimized dynamic influences on measurements (McGowan et al 2010; Wiebe et al 2011). EC measurements were corrected for tilt errors using the double rotation method for coordinate rotation described by Wilczak et al. (2001). High and low frequency attenuation of the measured co-spectrum was corrected using Massman's (2000) method for estimating frequency response corrections, while measurements were corrected for density fluctuations using the method of Webb-Pearman-Leuning (Webb et al. 1980). The evaporation measurement footprint over the reservoir was determined using the SCADIS one and a half order turbulence closure footprint model (Sogachev and Lloyd, 2004). Comparison of EC measured evaporation rates show excellent agreement with independent measurement of evaporation by scintillometer under a wide range of conditions (McJannet et al 2011). They confirm that pontoon mounted EC systems offer a robust, highly portable and reliable cost effective approach for accurate quantification of evaporation from reservoirs.

  13. Effects of oxygen flow rate on microstructure and optical properties of aluminum oxide films deposited by electron beam evaporation technique

    Microsoft Academic Search

    Namita Maiti; A. Biswas; R. B. Tokas; D. Bhattacharyya; S. N. Jha; U. P. Deshpande; U. D. Barve; M. S. Bhatia; A. K. Das

    2010-01-01

    Reactive evaporation technique has been used to deposit thin films of alumina (Al2O3) on crystalline Si substrates at ambient temperatures in an electron beam (e-beam) evaporation system using alumina granules as evaporant material. The loss of oxygen due to dissociation of alumina has been compensated by bleeding high purity oxygen gas into the system during evaporation. A set of samples

  14. A new production logging method for fullbore gas holdup measurements in cased wells

    SciTech Connect

    Waid, M.C.; Madigan, W.P.; Smith, H.D. Jr. [and others

    1996-12-31

    The measurement of the gas holdup in a flowing cased-hole environment is a fundamentally difficult problem. Gas holdup, the estimate percent of gas in a volume of wellbore, has traditionally been computed from fluid density measurements. These estimates are inadequate for determining gas holdup in deviated or horizontal wells since the fluid density was not a fullbore measurement. A new Gas Holdup Tool (GHT{trademark}) has been developed which provides a more accurate technique for obtaining gas holdup measurements directly. This 1 11/16-inch production logging tool is used to determine the volumetric fraction of gas in horizontal, deviated, and vertical cased wells, and provides a log of the gas holdup fraction (from 0% to 100%) in all flow regimes. Examples are presented for comparing homogeneous and stratified flows. The tool uses a low-energy Co-57 source and NaI detectors with a new backscatter technique to accurately measure density differences of the total fluid and gas in the borehole around the tool. This new measurement provides the gas fraction (holdup) in all flow regimes, and is not affected by the materials outside the casing. Monte Carlo modeling and experimental data over a wide range of cased-hole conditions validate empirical relationships between detector count rates and gas holdup for various casing diameters. The sensitivity of the measurement to other factors, such as pressure, salinity, and fluid type, are also investigated. The new production logging method may be used in determining points of gas and oil entry into deviated or horizontal wells and for quantitative production logging in deviated or horizontal wells with variable or unknown flow regimes.

  15. Flash evaporation of liquid monomer particle mixture

    DOEpatents

    Affinito, J.D.; Darab, J.G.; Gross, M.E.

    1999-05-11

    The present invention is a method of making a first solid composite polymer layer. The method has the steps of (a) mixing a liquid monomer with particles substantially insoluble in the liquid monomer forming a monomer particle mixture; (b) flash evaporating the particle mixture and forming a composite vapor; and (c) continuously cryocondensing said composite vapor on a cool substrate and cross-linking the cryocondensed film thereby forming the polymer layer. 3 figs.

  16. Flash evaporation of liquid monomer particle mixture

    DOEpatents

    Affinito, John D. (Kennewick, WA); Darab, John G. (Richland, WA); Gross, Mark E. (Pasco, WA)

    1999-01-01

    The present invention is a method of making a first solid composite polymer layer. The method has the steps of (a) mixing a liquid monomer with particles substantially insoluble in the liquid monomer forming a monomer particle mixture; (b) flash evaporating the particle mixture and forming a composite vapor; and (c) continuously cryocondensing said composite vapor on a cool substrate and cross-linking the cryocondensed film thereby forming the polymer layer.

  17. Experimental Investigation of Evaporation Behavior of Polonium and Rare-Earth Elements in Lead-Bismuth Eutectic Pool

    SciTech Connect

    Shuji Ohno; Shinya Miyahara; Yuji Kurata [Japan Atomic Energy Agency (Japan); Ryoei Katsura [Nippon Nuclear Fuel Development Co., Ltd. (Japan); Shigeru Yoshida [KAKEN Co., Ltd. (Japan)

    2006-07-01

    Equilibrium evaporation behavior was experimentally investigated for polonium ({sup 210}Po) in liquid lead-bismuth eutectic (LBE) and for rare-earth elements gadolinium (Gd) and europium (Eu) in LBE to understand and clarify the transfer behavior of toxic impurities from LBE coolant to a gas phase. The experiments utilized the 'transpiration method' in which saturated vapor in an isothermal evaporation pot was transported by inert carrier gas and collected outside of the pot. While the previous paper ICONE12-49111 has already reported the evaporation behavior of LBE and of tellurium in LBE, this paper summarizes the outlines and the results of experiments for important impurity materials {sup 210}Po and rare-earth elements which are accumulated in liquid LBE as activation products and spallation products. In the experiments for rare-earth elements, non-radioactive isotope was used. The LBE pool is about 330-670 g in weight and has a surface area of 4 cm x 14 cm. {sup 210}Po experiments were carried out with a smaller test apparatus and radioactive {sup 210}Po produced through neutron irradiation of LBE in the Japan Materials Testing Reactor (JMTR). We obtained fundamental and instructive evaporation data such as vapor concentration, partial vapor pressure of {sup 210}Po in the gas phase, and gas-liquid equilibrium partition coefficients of the impurities in LBE under the temperature condition between 450 and 750 deg. C. The {sup 210}Po test revealed that Po had characteristics to be retained in LBE but was still more volatile than LBE solvent. A part of Eu tests implied high volatility of rare-earth elements comparable to that of Po. This tendency is possibly related to the local enrichment of the solute near the pool surface and needs to be investigated more. These results are useful and indispensable for the evaluation of radioactive materials transfer to the gas phase in LBE-cooled nuclear systems. (authors)

  18. Some oxide films deposited by reactive low-voltage plasma-assisted evaporation

    Microsoft Academic Search

    Xu Liu; Bin Wang; Gan Wang; Peifu Gu; Jinfa Tang

    1993-01-01

    Low voltage plasma assisted evaporation (PAE) technique has been investigated as an effective evaporation technique for the deposition of oxide films of high optical performance. The PAE process consists of an electron beam evaporator and a large current plasma source. The guided wave method is used to measure the refractive index and attenuation coefficients of guided modes of some oxide

  19. Evaporation of tiny water aggregation on solid surfaces of different wetting properties

    E-print Network

    Shen Wang; Yusong Tu; Rongzheng Wan; Haiping Fang

    2012-03-08

    The evaporation of a tiny amount of water on the solid surface with different wettability has been studied by molecular dynamics simulations. We found that, as the surface changed from hydrophobicity to hydrophility, the evaporation speed did not show a monotonically decrease from intuition, but increased first, and then decreased after reached a maximum value. The competition between the number of the water molecules on the water-gas surface from where the water molecules can evaporate and the potential barrier to prevent those water molecules from evaporating results in the unexpected behavior of the evaporation. A theoretical model based on those two factors can fit the simulation data very well. This finding is helpful in understanding the evaporation on the biological surfaces, designing artificial surface of ultra fast water evaporating or preserving water in soil.

  20. Effects of swift heavy ion irradiation on structural, optical and photocatalytic properties of ZnO–CuO nanocomposites prepared by carbothermal evaporation method

    PubMed Central

    Kuriakose, Sini; Avasthi, D K

    2015-01-01

    Summary ZnO–CuO nanocomposite thin films were prepared by carbothermal evaporation of ZnO and Cu, combined with annealing. The effects of 90 MeV Ni7+ ion irradiation on the structural and optical properties of ZnO–CuO nanocomposites were studied by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV–visible absorption spectroscopy and Raman spectroscopy. XRD studies showed the presence of ZnO and CuO nanostructures in the nanocomposites. FESEM images revealed the presence of nanosheets and nanorods in the nanocomposites. The photocatalytic activity of ZnO–CuO nanocomposites was evaluated on the basis of degradation of methylene blue (MB) and methyl orange (MO) dyes under sun light irradiation and it was observed that swift heavy ion irradiation results in significant enhancement in the photocatalytic efficiency of ZnO–CuO nanocomposites towards degradation of MB and MO dyes. The possible mechanism for the enhanced photocatalytic activity of ZnO–CuO nanocomposites is proposed. We attribute the observed enhanced photocatalytic activity of ZnO–CuO nanocomposites to the combined effects of improved sun light utilization and suppression of the recombination of photogenerated charge carriers in ZnO–CuO nanocomposites. PMID:25977864

  1. Apparatus and method of using a fuel gas regulator for a coke oven battery

    SciTech Connect

    Dickerson, D.M.; Filkes, R.W.

    1985-08-06

    Method and apparatus for the regulation of the flow of fuel gas in the fuel gas supply duct of a heating wall of a coke oven to assure uniform heat distribution in the oven are provided. The regulating means consists of a thin plate having a similar shape to that of a fuel gas supply duct for insertion therein. Pivotally attached to and extending perpendicularly from the outer face of the plate are twin parallel control rods with gage marks inscribed thereon. To effect the regulation of fuel gas flow, the regulating means is inserted into the fuel gas supply duct at an appropriate location and the flow rate is adjusted by pivoting the plate by the manipulation of the adjusting rods.

  2. Method for recovering and utilizing heat of coke-oven gas

    SciTech Connect

    Kunioka, K.; Nishio, H.; Okuyama, Y.; Shimotsuma, T.

    1981-06-02

    A method is described for recovering and utilizing heat of coke- oven gas is eliminated. Through heat exchange with a high-temperature coke-oven gas generated from a coke oven battery and containing vaporized coal tar, vaporized low boiling point substances and dust. By drying and preheating a blended raw material coal fine to be charged into coking ovens of said coke oven battery, and causing most of said coal tar contained in said coke-oven gas to condense and deposit onto the particle surfaces of said coal fine. During the process of said heat exchange, sensible heat and condensation heat of said coke-oven gas and substances contained therein are recovered and utilized, and at the same time, most of the contained coal tar from said coke-oven gas.

  3. Method and apparatus for filtering gas with a moving granular filter bed

    DOEpatents

    Brown, Robert C. (Ames, IA); Wistrom, Corey (Ames, IA); Smeenk, Jerod L. (Ames, IA)

    2007-12-18

    A method and apparatus for filtering gas (58) with a moving granular filter bed (48) involves moving a mass of particulate filter material (48) downwardly through a filter compartment (35); tangentially introducing gas into the compartment (54) to move in a cyclonic path downwardly around the moving filter material (48); diverting the cyclonic path (58) to a vertical path (62) to cause the gas to directly interface with the particulate filter material (48); thence causing the gas to move upwardly through the filter material (48) through a screened partition (24, 32) into a static upper compartment (22) of a filter compartment for exodus (56) of the gas which has passed through the particulate filter material (48).

  4. A method to estimate weight and dimensions of large and small gas turbine engines

    NASA Technical Reports Server (NTRS)

    Onat, E.; Klees, G. W.

    1979-01-01

    A computerized method was developed to estimate weight and envelope dimensions of large and small gas turbine engines within + or - 5% to 10%. The method is based on correlations of component weight and design features of 29 data base engines. Rotating components were estimated by a preliminary design procedure which is sensitive to blade geometry, operating conditions, material properties, shaft speed, hub tip ratio, etc. The development and justification of the method selected, and the various methods of analysis are discussed.

  5. Investigation of heat transfer by evaporation in capillary grooves with a porous coating

    NASA Astrophysics Data System (ADS)

    Vasil'ev, L. L.; Grakovich, L. P.; Rabetskii, M. I.; Tulin, D. V.

    2012-03-01

    The results of experimental investigations of heat pipe evaporators with axial grooves of various profiles are presented. A method for enhancing heat transfer by liquid evaporation from capillary grooves of evaporators is proposed. It is realized by applying to the capillary groove surface a thin (25-100 ?m) porous coating containing pores up to nanosize. The use of such a coating has made it possible to increase the heat transfer coefficients by evaporation by a factor of 1.5-2.

  6. Simple method for predicting viscosity of gas mixtures

    NASA Technical Reports Server (NTRS)

    Brokaw, R. S.

    1970-01-01

    Method is derived from the Chapman-enskog theory which describes viscosities at low-to-moderate pressures. Mixtures of nonpolar gases require the viscosities and molecular weights of the constituents in addition to the mixture composition. Dipole moments, boiling points and liquid boiling point densities are also needed with polar gases.

  7. Impact design methods for ceramic components in gas turbine engines

    NASA Technical Reports Server (NTRS)

    Song, J.; Cuccio, J.; Kington, H.

    1991-01-01

    Methods currently under development to design ceramic turbine components with improved impact resistance are presented. Two different modes of impact damage are identified and characterized, i.e., structural damage and local damage. The entire computation is incorporated into the EPIC computer code. Model capability is demonstrated by simulating instrumented plate impact and particle impact tests.

  8. Clay stabilizing method for oil and gas well treatment

    SciTech Connect

    Aften, C.W.; Gabel, R.K.

    1992-03-31

    This patent describes a method for stabilizing a clay-containing formation for down-hole well stimulation, comprising the step of contacting the formation with a stimulation fluid. It comprises: tetraalkylammonium chloride; and a quaternary amine-based cationic polyelectrolyte.

  9. Advancing New 3D Seismic Interpretation Methods for Exploration and Development of Fractured Tight Gas Reservoirs

    SciTech Connect

    James Reeves

    2005-01-31

    In a study funded by the U.S. Department of Energy and GeoSpectrum, Inc., new P-wave 3D seismic interpretation methods to characterize fractured gas reservoirs are developed. A data driven exploratory approach is used to determine empirical relationships for reservoir properties. Fractures are predicted using seismic lineament mapping through a series of horizon and time slices in the reservoir zone. A seismic lineament is a linear feature seen in a slice through the seismic volume that has negligible vertical offset. We interpret that in regions of high seismic lineament density there is a greater likelihood of fractured reservoir. Seismic AVO attributes are developed to map brittle reservoir rock (low clay) and gas content. Brittle rocks are interpreted to be more fractured when seismic lineaments are present. The most important attribute developed in this study is the gas sensitive phase gradient (a new AVO attribute), as reservoir fractures may provide a plumbing system for both water and gas. Success is obtained when economic gas and oil discoveries are found. In a gas field previously plagued with poor drilling results, four new wells were spotted using the new methodology and recently drilled. The wells have estimated best of 12-months production indicators of 2106, 1652, 941, and 227 MCFGPD. The latter well was drilled in a region of swarming seismic lineaments but has poor gas sensitive phase gradient (AVO) and clay volume attributes. GeoSpectrum advised the unit operators that this location did not appear to have significant Lower Dakota gas before the well was drilled. The other three wells are considered good wells in this part of the basin and among the best wells in the area. These new drilling results have nearly doubled the gas production and the value of the field. The interpretation method is ready for commercialization and gas exploration and development. The new technology is adaptable to conventional lower cost 3D seismic surveys.

  10. Histogrammatic Method for Determining Relative Abundance of Input Gas Pulse

    NASA Technical Reports Server (NTRS)

    Mandrake, Lukas; Bornstein, Benjamin J.; Madzunkov, Stojan; MacAskill, John A.

    2012-01-01

    To satisfy the Major Constituents Analysis (MCA) requirements for the Vehicle Cabin Atmosphere Monitor (VCAM), this software analyzes the relative abundance ratios for N2, O2, Ar, and CO2 as a function of time and constructs their best-estimate mean. A histogram is first built of all abundance ratios for each of the species vs time. The abundance peaks corresponding to the intended measurement and any obfuscating background are then separated via standard peak-finding techniques in histogram space. A voting scheme is then used to include/exclude this particular time sample in the final average based on its membership to the intended measurement or the background population. This results in a robust and reasonable estimate of the abundance of trace components such as CO2 and Ar even in the presence of obfuscating backgrounds internal to the VCAM device. VCAM can provide a means for monitoring the air within the enclosed environments, such as the ISS (International Space Station), Crew Exploration Vehicle (CEV), a Lunar Habitat, or another vehicle traveling to Mars. Its miniature pre-concentrator, gas chromatograph (GC), and mass spectrometer can provide unbiased detection of a large number of organic species as well as MCA analysis. VCAM s software can identify the concentration of trace chemicals and whether the chemicals are on a targeted list of hazardous compounds. This innovation s performance and reliability on orbit, along with the ground team s assessment of its raw data and analysis results, will validate its technology for future use and development.

  11. The Tracer Gas Method of Determining the Charging Efficiency of Two-stroke-cycle Diesel Engines

    NASA Technical Reports Server (NTRS)

    Schweitzer, P H; Deluca, Frank, Jr

    1942-01-01

    A convenient method has been developed for determining the scavenging efficiency or the charging efficiency of two-stroke-cycle engines. The method consists of introducing a suitable tracer gas into the inlet air of the running engine and measuring chemically its concentration both in the inlet and exhaust gas. Monomethylamine CH(sub 3)NH(sub 2) was found suitable for the purpose as it burns almost completely during combustion, whereas the "short-circuited" portion does not burn at all and can be determined quantitatively in the exhaust. The method was tested both on four-stroke and on two-stroke engines and is considered accurate within 1 percent.

  12. Design and performance of an absolute gas refractometer based on quasi-synthetic wavelength method

    E-print Network

    Zhang, Jitao; Li, Yan; Wei, Haoyun

    2012-01-01

    We present a refractometer which is capable of measuring the refractive index of gas with an unambiguous range of 1.000395 and uncertainty of 3.1E-8 at 633 nm absolutely. The measurement range is extended by means of a group of vacuum tubes according to the principle of quasi-synthetic wavelength (QSW) method. The basic principle of the QSW method and the design of the gas refractometer are presented in detail. The performance of the refractometer has been verified by the measurement of dry air, nitrogen gas and ambient air under different environmental situations. The gas-filling or pumping process is not needed during the measurement, so that we can complete a measurement within 70 seconds. Comparing with previous ones, the refractometer reported here has integrated virtues of large unambiguous range, fast speed, high accuracy, and a simple instrumentation design.

  13. Small Scale Evaporation Kinetics of a Binary Fluid Mixture

    NASA Astrophysics Data System (ADS)

    Basdeo, Carl; Ye, Dezhuang; Kalonia, Devendra; Fan, Tai-Hsi; Mechanical Engineering Team; Pharmaceutical Sciences Collaboration

    2013-03-01

    Evaporation induces a concentrating effect in liquid mixtures. The transient process has significant influence on the dynamic behaviors of a complex fluid. To simultaneously investigate the fluid properties and small-scale evaporation kinetics during the transient process, the quartz crystal microbalance is applied to a binary mixture droplet of light alcohols including both a single volatile component (a fast evaporation followed by a slow evaporation) and a mixture of two volatile components with comparable evaporation rates. The density and viscosity stratification are evaluated by the shear wave, and the evaporation kinetics is measured by the resonant signature of the acoustic p-wave. The evaporation flux can be precisely determined by the resonant frequency spikes and the complex impedance. To predict the concentration field, the moving interface, and the precision evaporation kinetics of the mixture, a multiphase model is developed to interpret the complex impedance signals based on the underlying mass and momentum transport phenomena. The experimental method and theoretical model are developed for better characterizing and understanding of the drying process involving liquid mixtures of protein pharmaceuticals.

  14. Method of gas mixtures discrimination based on sensor array, temporal response and data driven approach

    Microsoft Academic Search

    A. Szczurek; M. Maciejewska; B. Flisowska-Wiercik

    2011-01-01

    This work presents a method of gas mixtures discrimination. The principal concept of the method is to apply measurement data provided by a combination of sensors at single time point of their temporal response as input of the discrimination models. The pattern data combinations are selected for classes of target gases based on the criterion of 100% efficient discrimination. Combinations

  15. COMPARISON AND ANALYSIS OF ON-LINE PARTIAL DISCHARGE MEASUREMENT METHODS FOR GAS INSULATION SUBSTATION

    Microsoft Academic Search

    Chien-Yi Chen; Cheng-Chi Tai; Ju-Chu Hsieh; Ching-Chau Su; Jiann-Fuh Chen

    In this paper, we compare and analyze the signals of acoustic emission (AE) sensor, high-frequency current transformer (HF-CT) and capacitive coupled (CC) sensor inspection methods when they are used to detect the partial discharge (PD) in gas isolation substations (GIS). The PD location feasibility of the AE method is also studied. In general, the leakage currents are measured by using

  16. REVIEW OF METHODS OF OPTICAL GAS Detection by Direct Optical Spectroscopy, with Emphasis on Correlation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Dakin, John P.; Chambers, Paul

    This chapter reviews the development of optical gas sensors, starting with an initial emphasis on optical-fibre remoted techniques and finishing with a particular focus on our own group's work on highly selective methods using correlation spectroscopy. This latter section includes extensive theoretical modelling of a correlation spectroscopy method, and compares theory with practice for a CO2 sensor.

  17. Comparison of empirical and semi-empirical calculation methods for venting of gas explosions

    Microsoft Academic Search

    D. M. Razus; U. Krause

    2001-01-01

    Venting is a widely applied method to protect process equipment from being destroyed by internal explosions. The key problem in venting is the appropriate design of the vent area necessary for an effective release of the material. For gas explosions different calculation methods exist, but there are no clear recommendations which one should be preferred for the practical cases under

  18. New instrumental method for determining noble fission gas retained in irradiated nuclear fuels

    Microsoft Academic Search

    1981-01-01

    The measurement of fission products generated in nuclear fuel is necessary for the complete characterization of the irradiated fuel. The gaseous fission products, xenon and krypton, are of particular importance. A new method has been developed for the measurement of the fission gas retained in nuclear fuel. The method involves extraction of xenon and krypton by melting the fuel in

  19. REVIEW ARTICLE: Method for counting noble gas atoms with isotopic selectivity

    Microsoft Academic Search

    G. S. Hurst; M. G. Payne; S. D. Kramer; C. H. Chen; R. C. Phillips; S. L. Allman; G. D. Alton; J. W. T. Dabbs; R. D. Willis; B. E. Lehmann

    1985-01-01

    A method has been developed for direct counting of noble gas atoms and has been demonstrated for selected isotopes of krypton. In principle, a few atoms of the noble gases argon, krypton, xenon and radon can now be counted with isotopic selectivity whether stable or radioactive. A concept was originated in which a laser method would be used to count

  20. Automated Nondestructive Evaluation Method for Characterizing Ceramic and Metallic Hot Gas Filters

    SciTech Connect

    Ellingson, W.A.; Pastila, P.; Koehl, E.R.; Wheeler, B.; Deemer, C.; Forster, G.A.

    2002-09-19

    The objective of this work was to develop a nondestructive (NDE), cost-effective and reliable method to assess the condition of rigid ceramic hot gas filters. The work was intended to provide an end user, as well as filter producers, with a nondestructive method to assess the ''quality'' or status of the filters.

  1. Apparatus and method for a gas turbine nozzle

    DOEpatents

    Zuo, Baifang; Ziminsky, Willy Steve; Johnson, Thomas Edward; Intile, John Charles; Lacy, Benjamin Paul

    2013-02-05

    A nozzle includes an inlet, an outlet, and an axial centerline. A shroud surrounding the axial centerline extends from the inlet to the outlet and defines a circumference. The circumference proximate the inlet is greater than the circumference at a first point downstream of the inlet, and the circumference at the first point downstream of the inlet is less than the circumference at a second point downstream of the first point. A method for supplying a fuel through a nozzle directs a first airflow along a first path and a second airflow along a second path separate from the first path. The method further includes injecting the fuel into at least one of the first path or the second path and accelerating at least one of the first airflow or the second airflow.

  2. Stress analysis of gas turbine engine structures using the boundary element method

    NASA Technical Reports Server (NTRS)

    Wilson, R. B.; Snow, D. W.; Banerjee, P. K.

    1985-01-01

    The theory of the boundary element method is briefly reviewed with particular reference to the feasibility of elastic and inelastic three-dimensional stress analysis of complex structures characteristic of gas turbine engine components. Particular requirements of gas turbine analysis are defined, and examples of the use of a boundary element code designed for the three-dimensional stress analysis of turbine components are presented. It is shown that the general-purpose boundary element code can accurately and efficiently analyze many of the gas turbine engine structures.

  3. Thermal chemical recuperation method and system for use with gas turbine systems

    DOEpatents

    Yang, W.C.; Newby, R.A.; Bannister, R.L.

    1999-04-27

    A system and method are disclosed for efficiently generating power using a gas turbine, a steam generating system and a reformer. The gas turbine receives a reformed fuel stream and an air stream and produces shaft power and exhaust. Some of the thermal energy from the turbine exhaust is received by the reformer. The turbine exhaust is then directed to the steam generator system that recovers thermal energy from it and also produces a steam flow from a water stream. The steam flow and a fuel stream are directed to the reformer that reforms the fuel stream and produces the reformed fuel stream used in the gas turbine. 2 figs.

  4. Method to measure gas levels during auger mining of coal. Information circular/1994

    SciTech Connect

    Volkwein, J.C.; Prokop, A.D.

    1994-01-01

    The U.S. Bureau of Mines has developed a method to measure methane and other gases during the auger mining of coal. An intrinsically safe commercial gas detector with a built-in data logger was mounted in the center of the hollow conveying auger. A sample head through the wall of the auger conducted a gas sample to the detector. Results showed that gas levels can be monitored on a continuous basis during the auger mining of coal and the data retrieved upon completion of the hole.

  5. A method for the determination of dissolved organic carbon in sea water by gas chromatography 

    E-print Network

    Fredericks, Alan D

    1965-01-01

    METHODS Reagents Used in Carbon Analysis Potassium ersulfate. Analytical reagent grade potassium persulfate crystals (Mallinckrodt Chemical Works) of 99% purity were used as the oxidizing agent. Phos horic acid solution. Concentrated reagent grade... (Mallinckrodt Chemical Works) was used to remove chlorine gas from the carrier gas stream prior to entering the separating column. Glass am oules. Five ml, plain stem, non-corrosive type glass ampoules with external measurements of 16 mm. X 80 mm. were used...

  6. Method and apparatus for perforating at cutting with a solid fueled gas mixture

    SciTech Connect

    Woytek, A.J.; Lileck, J.T.; Steigerwalt, E.J.

    1984-05-08

    A method for cutting pipe casings and concrete liners or perforating the same and localized portions of surrounding strata in an earth bore is set forth wherein a gas phase cutting or perforating jet mixture of fluorine and nitrogen trifluoride is delivered to the cutting or perforation site from the decomposition of a solid, normally stable, perfluoroammonium salt. An appropriate apparatus for delivering the gas mixture of fluorine and nitrogen trifluoride from the salt is also disclosed.

  7. Climatological estimates of lake evaporation

    Microsoft Academic Search

    F. I. Morton

    1979-01-01

    A model for estimating areal evaporation and transpiration is modified slightly to provide estimates of annual lake evaporation from monthly observations of temperature, humidity, and sunshine duration (or radiation) in the land environment. The model estimates tend to be higher than the more conventional estimates in humid areas and lower in arid areas, with the latter tendency particularly noticeable in

  8. Evaporative cooling of sodium atoms

    Microsoft Academic Search

    Kendall B. Davis; Marc-Oliver Mewes; Michael A. Joffe; Michael R. Andrews; Wolfgang Ketterle

    1995-01-01

    We have observed evaporative cooling of magnetically trapped sodium atoms. A novel technique, rf induced evaporation, was used to reduce the temperature by a factor of 12 and increase the phase space density by more than 2 orders of magnitude. The elastic collision cross section of cold sodium atoms in the {ital F}=1, {ital m}{sub {ital F}}=-1 hyperfine state was

  9. DWPF Recycle Evaporator Simulant Tests

    Microsoft Academic Search

    2005-01-01

    Testing was performed to determine the feasibility and processing characteristics of an evaporation process to reduce the volume of the recycle stream from the Defense Waste Processing Facility (DWPF). The concentrated recycle would be returned to DWPF while the overhead condensate would be transferred to the Effluent Treatment Plant. Various blends of evaporator feed were tested using simulants developed from

  10. Black Hole - Never Forms, or Never Evaporates

    E-print Network

    Sun Yi

    2011-03-21

    Many discussion about the black hole conundrums, such as singularity and information loss, suggested that there must be some essential irreconcilable conflict between quantum theory and classical gravity theory, which cannot be solved with any semiclassical quantized model of gravity, the only feasible way must be some complete unified quantum theory of gravity. In \\cite{Vachaspati2007a}, the arguments indicate the possibility of an alternate outcome of gravitational collapse which avoids the information loss problem. In this paper, also with semiclassical analysis, it shows that so long as the mechanism of black hole evaporation satisfies a quite loose condition that the evaporation lifespan is finite for external observers, regardless of the detailed mechanism and process of evaporation, the conundrums above can be naturally avoided. This condition can be satisfied with Hawking-Unruh mechanism. Thus, the conflict between quantum theory and classical gravity theory may be not as serious as it seemed to be, the effectiveness of semiclassical methods might be underestimated. An exact universal solution with spherical symmetry of Einstein field equation has been derived in this paper. All possible solutions with spherical symmetry of Einstein field equation are its special cases. In addition, some problems of the Penrose diagram of an evaporating black hole first introduced by Hawking in 1975 \\cite{Hawking1975} are clarified.

  11. CHEMISTRY IN EVAPORATING ICES-UNEXPLORED TERRITORY

    SciTech Connect

    Cecchi-Pestellini, Cesare [INAF-Osservatorio Astronomico di Cagliari, Strada n.54, Loc. Poggio dei Pini, 09012 Capoterra (Italy); Rawlings, Jonathan M. C.; Viti, Serena; Williams, David A., E-mail: ccp@ca.astro.i, E-mail: jcr@star.ucl.ac.u, E-mail: sv@star.ucl.ac.u, E-mail: daw@star.ucl.ac.u [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2010-12-20

    We suggest that three-body chemistry may occur in warm high-density gas evaporating in transient co-desorption events on interstellar ices. Using a highly idealized computational model we explore the chemical conversion from simple species of the ice to more complex species containing several heavy atoms, as a function of density and of adopted three-body rate coefficients. We predict that there is a wide range of densities and rate coefficients in which a significant chemical conversion may occur. We discuss the implications of this idea for the astrochemistry of hot cores.

  12. Methods for natural gas and heavy hydrocarbon co-conversion

    DOEpatents

    Kong, Peter C. (Idaho Falls, ID); Nelson, Lee O. (Idaho Falls, ID); Detering, Brent A. (Idaho Falls, ID)

    2009-02-24

    A reactor for reactive co-conversion of heavy hydrocarbons and hydrocarbon gases and includes a dielectric barrier discharge plasma cell having a pair of electrodes separated by a dielectric material and passageway therebetween. An inlet is provided for feeding heavy hydrocarbons and other reactive materials to the passageway of the discharge plasma cell, and an outlet is provided for discharging reaction products from the reactor. A packed bed catalyst may optionally be used in the reactor to increase efficiency of conversion. The reactor can be modified to allow use of a variety of light sources for providing ultraviolet light within the discharge plasma cell. Methods for upgrading heavy hydrocarbons are also disclosed.

  13. Method for the photocatalytic conversion of gas hydrates

    DOEpatents

    Taylor, Charles E. (Pittsburg, PA); Noceti, Richard P. (Pittsburg, PA); Bockrath, Bradley C. (Bethel Park, PA)

    2001-01-01

    A method for converting methane hydrates to methanol, as well as hydrogen, through exposure to light. The process includes conversion of methane hydrates by light where a radical initiator has been added, and may be modified to include the conversion of methane hydrates with light where a photocatalyst doped by a suitable metal and an electron transfer agent to produce methanol and hydrogen. The present invention operates at temperatures below 0.degree. C., and allows for the direct conversion of methane contained within the hydrate in situ.

  14. Evaporation characteristics of ETBE-blended gasoline.

    PubMed

    Okamoto, Katsuhiro; Hiramatsu, Muneyuki; Hino, Tomonori; Otake, Takuma; Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi

    2015-04-28

    To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were developed. PMID:25644031

  15. Experimental Investigation of Microstructured Evaporators

    NASA Astrophysics Data System (ADS)

    Wibel, W.; Westermann, S.; Maikowske, S.; Brandner, J. J.

    2012-11-01

    Microfluidic devices have become more and more popular over the last decades [1]. Cooling is a topic where microstructures offer significant advantages compared to conventional techniques due the much higher possible surface to volume ratios and short heat transfer lengths. By evaporating of a fluid in microchannels, compact, fast and powerful cooling devices become possible [2]. Experimental results for different designs of microstructured evaporators are presented here. They have been obtained either using water as evaporating coolant or the refrigerant R134a (Tetrafluoroethane). A new microstructured evaporator design consisting of bended microchannels instead of straight channels for a better performance is shown and compared to previous results [2] for the evaporation of R134a in straight microchannels.

  16. Cold Flow PIV and Spray Visualization Experiments Applied to the Development of ALSTOM Dual Fuel Gas Turbine Burners

    Microsoft Academic Search

    Stefano Bernero; Adrian Glauser; Martin Zajadatz

    The development of liquid fuel injectors for dual fuel gas turbine burners involves complex processes like spray formation and evaporation of single and multi phase fluids under high temperature and pressure conditions. Since for such complex phenomena satisfactory numerical modeling methods are still under development, experiments play a key role in the development process. Gas turbine testing or full-scale experiments

  17. Generalized average of signals (GAS) - a new method for denoising and phase detection

    NASA Astrophysics Data System (ADS)

    Malek, J.; Kolinsky, P.; Strunc, J.; Valenta, J.

    2007-12-01

    A novel method called Generalized Average of Signals (GAS) was developed and tested during the last two years (Málek et al., in press). This method is designed for processing of seismograms from dense seismic arrays and is convenient mainly for denoising and weak phase detection. The main idea of the GAS method is based on non-linear stacking of seismograms in frequency domain, which considerably improves signal-to-noise ratio of coherent seismograms. Several synthetic tests of the GAS method are presented and the results are compared with the PWS method of Schimell and Paulssen (1997). Moreover, examples of application on real data are presented. These examples were chosen to show a broad applicability of the method in experiments of different scales. The first one shows identification of S-waves on seismograms from shallow seismic. The second one concerns identification of converted waves from local earthquakes registered at the WEBNET local network in western Bohemia. Finally, the third one depicts identification of PKIKP onsets on seismograms of teleseismic earthquakes. Schimmel, M., Paulssen H. (1997): Noise reduction and detection of weak, coherent signals through phase- weighted stacks. Geophys. J. Int. 130, 497-505. Málek J., Kolínský P., Strunc J. and Valenta J. (2007): Generalized average of signals (GAS) - a new method for detection of very weak waves in seismograms. Acta Geodyn. et Geomater., in press.

  18. Automatic method for evaluating the activity of sourdough strains based on gas pressure measurements.

    PubMed

    Wick, M; Vanhoutte, J J; Adhemard, A; Turini, G; Lebeault, J M

    2001-04-01

    A new method is proposed for the evaluation of the activity of sourdough strains, based on gas pressure measurements in closed air-tight reactors. Gas pressure and pH were monitored on-line during the cultivation of commercial yeasts and heterofermentative lactic acid bacteria on a semi-synthetic medium with glucose as the major carbon source. Relative gas pressure evolution was compared both to glucose consumption and to acidification and growth. It became obvious that gas pressure evolution is related to glucose consumption kinetics. For each strain, a correlation was made between maximum gas pressure variation and amount of glucose consumed. The mass balance of CO2 in both liquid and gas phase demonstrated that around 90% of CO2 was recovered. Concerning biomass production, a linear relationship was found between log colony-forming units/ml and log pressure for both yeasts and bacteria during the exponential phase; and for yeasts, relative gas pressure evolution also followed optical density variation. PMID:11341320

  19. Apparatus for the liquefaction of natural gas and methods relating to same

    DOEpatents

    Wilding, Bruce M. (Idaho Falls, ID); Bingham, Dennis N. (Idaho Falls, ID); McKellar, Michael G. (Idaho Falls, ID); Turner, Terry D. (Ammon, ID); Raterman, Kevin T. (Idaho Falls, ID); Palmer, Gary L. (Shelley, ID); Klingler, Kerry M. (Idaho Falls, ID); Vranicar, John J. (Concord, CA)

    2007-05-22

    An apparatus and method for producing liquefied natural gas. A liquefaction plant may be coupled to a source of unpurified natural gas, such as a natural gas pipeline at a pressure letdown station. A portion of the gas is drawn off and split into a process stream and a cooling stream. The cooling stream passes through a turbo expander creating work output. A compressor is driven by the work output and compresses the process stream. The compressed process stream is cooled, such as by the expanded cooling stream. The cooled, compressed process stream is divided into first and second portions with the first portion being expanded to liquefy the natural gas. A gas-liquid separator separates the vapor from the liquid natural gas. The second portion of the cooled, compressed process stream is also expanded and used to cool the compressed process stream. Additional features and techniques may be integrated with the liquefaction process including a water clean-up cycle and a carbon dioxide (CO.sub.2) clean-up cycle.

  20. Apparatus For The Liquefaaction Of Natural Gas And Methods Relating To Same

    DOEpatents

    Wilding, Bruce M. (Idaho Falls, ID); Bingham, Dennis N. (Idaho Falls, ID); McKellar, Michael G. (Idaho Falls, ID); Turner, Terry D. (Ammon, ID); Rateman, Kevin T. (Idaho Falls, ID); Palmer, Gary L. (Shelley, ID); Klinger, Kerry M. (Idaho Falls, ID); Vranicar, John J. (Concord, CA)

    2005-11-08

    An apparatus and method for producing liquefied natural gas. A liquefaction plant may be coupled to a source of unpurified natural gas, such as a natural gas pipeline at a pressure letdown station. A portion of the gas is drawn off and split into a process stream and a cooling stream. The cooling stream passes through a turbo expander creating work output. A compressor is driven by the work output and compresses the process stream. The compressed process stream is cooled, such as by the expanded cooling stream. The cooled, compressed process stream is divided into first and second portions with the first portion being expanded to liquefy the natural gas. A gas-liquid separator separates the vapor from the liquid natural gas. The second portion of the cooled, compressed process stream is also expanded and used to cool the compressed process stream. Additional features and techniques may be integrated with the liquefaction process including a water clean-up cycle and a carbon dioxide (CO2) clean-up cycle.

  1. Apparatus For The Liquefaaction Of Natural Gas And Methods Relating To Same

    DOEpatents

    Wilding, Bruce M. (Idaho Falls, ID); Bingham, Dennis N. (Idaho Falls, ID); McKellar, Michael G. (Idaho Falls, ID); Turner, Terry D. (Ammon, ID); Raterman, Kevin T. (Idaho Falls, ID); Palmer, Gary L. (Shelley, ID); Klingler, Kerry M. (Idaho Falls, ID); Vranicar, John J. (Concord, CA)

    2003-06-24

    An apparatus and method for producing liquefied natural gas. A liquefaction plant may be coupled to a source of unpurified natural gas, such as a natural gas pipeline at a pressure letdown station. A portion of the gas is drawn off and split into a process stream and a cooling stream. The cooling stream passes through a turbo expander creating work output. A compressor is driven by the work output and compresses the process stream. The compressed process stream is cooled, such as by the expanded cooling stream. The cooled, compressed process stream is divided into first and second portions with the first portion being expanded to liquefy the natural gas. A gas-liquid separator separates the vapor from the liquid natural gas. The second portion of the cooled, compressed process stream is also expanded and used to cool the compressed process stream. Additional features and techniques may be integrated with the liquefaction process including a water clean-up cycle and a carbon dioxide (CO.sub.2) clean-up cycle.

  2. Apparatus For The Liquefaaction Of Natural Gas And Methods Relating To Same

    DOEpatents

    Wilding, Bruce M. (Idaho Falls, ID); Bingham, Dennis N. (Idaho Falls, ID); McKellar, Michael G. (Idaho Falls, ID); Turner, Terry D. (Ammon, ID); Raterman, Kevin T. (Idaho Falls, ID); Palmer, Gary L. (Shelley, ID); Klingler, Kerry M. (Idaho Falls, ID); Vranicar, John J. (Concord, CA)

    2005-05-03

    An apparatus and method for producing liquefied natural gas. A liquefaction plant may be coupled to a source of unpurified natural gas, such as a natural gas pipeline at a pressure letdown station. A portion of the gas is drawn off and split into a process stream and a cooling stream. The cooling stream passes through a turbo expander creating work output. A compressor is driven by the work output and compresses the process stream. The compressed process stream is cooled, such as by the expanded cooling stream. The cooled, compressed process stream is divided into first and second portions with the first portion being expanded to liquefy the natural gas. A gas-liquid separator separates the vapor from the liquid natural gas. The second portion of the cooled, compressed process stream is also expanded and used to cool the compressed process stream. Additional features and techniques may be integrated with the liquefaction process including a water clean-up cycle and a carbon dioxide (CO2) clean-up cycle.

  3. Transparent electrical conducting films by activated reactive evaporation

    Microsoft Academic Search

    R. Bunshah; P. Nath

    1982-01-01

    Process and apparatus for producing transparent electrical conducting thin films by activated reactive evaporation is disclosed. Thin films of low melting point metals and alloys, such as indium oxide and indium oxide doped with tin, are produced by physical vapor deposition. The metal or alloy is vaporized by electrical resistance heating in a vacuum chamber, oxygen and an inert gas

  4. Transparent electrical conducting films by activated reactive evaporation

    Microsoft Academic Search

    Rointan Bunshah; Prem Nath

    1982-01-01

    Process and apparatus for producing transparent electrical conducting thin films by activated reactive evaporation. Thin films of low melting point metals and alloys, such as indium oxide and indium oxide doped with tin, are produced by physical vapor deposition. The metal or alloy is vaporized by electrical resistance heating in a vacuum chamber, oxygen and an inert gas such as

  5. Development of a Direct Evaporator for the Organic Rankine Cycle

    Microsoft Academic Search

    Donna Post Guillen; Helge Klockow; Matthew Lehar; Sebastian Freund; Jennifer Jackson

    2011-01-01

    This paper describes research and development currently underway to place the evaporator of an Organic Rankine Cycle (ORC) system directly in the path of a hot exhaust stream produced by a gas turbine engine. The main goal of this research effort is to improve cycle efficiency and cost by eliminating the usual secondary heat transfer loop. The projects technical objective

  6. Comparison of Several Methods of Cyclic De-Icing of a Gas-Heated Airfoil

    NASA Technical Reports Server (NTRS)

    Gray, Vernon H.; Bowden, Dean T.

    1953-01-01

    Several methods of cyclic de-icing of a gas-heated airfoil were investigated to determine ice-removal characteristics and heating requirements. The cyclic de-icing system with a spanwise ice-free parting strip in the stagnation region and a constant-temperature gas-supply duct gave the quickest and most reliable ice removal. Heating requirements for the several methods of cyclic de-icing are compared, and the savings over continuous ice prevention are shown. Data are presented to show the relation of surface temperature, rate of surface heating, and heating time to the removal of ice.

  7. Chemical fingerprinting of gasoline. 2. Comparison of unevaporated and evaporated automotive gasoline samples.

    PubMed

    Sandercock, P M L; Du Pasquier, E

    2004-02-10

    Analysis of the C(0)- to C(2)-naphthalene compounds present in automotive gasoline using gas chromatography-mass spectrometry with selected ion monitoring (GC-MS (SIM)) and principal component analysis (PCA) was used to discriminate between different samples of gasoline. Phase one of this study explored the ability of this method to differentiate gasoline samples at different levels of evaporation. A total of 35 random samples of unevaporated gasoline, covering three different grades (regular unleaded, premium unleaded and lead replacement), were collected in Sydney, Australia and examined. The high-boiling C(0)- to C(2)-naphthalene compounds present in the gasoline were used to chemically fingerprint each sample at different levels of evaporation. Samples of 25, 50, 75 and 90% evaporated gasoline (by weight) were generated from the 35 samples of unevaporated gasoline. Analysis of the data by PCA followed by linear discriminant analysis (LDA) showed that the 35 samples formed 18 unique groups, irrespective of the level of evaporation. Good discrimination between gasoline samples that were collected on the same day was obtained. Phase two of this study examined the change in gasoline samples over time. The C(0)- to C(2)-naphthalene composition in 96 samples of gasoline collected from three service stations over a 16-week period was examined using the method described. In most cases, it was found that the C(0)- to C(2)-naphthalene profile changed from week to week, and from station to station. In a comparison of all 96 samples together it was found that the majority could be differentiated from one another. The application of the method to forensic casework is discussed. PMID:15013165

  8. Efficient method of gas laser pumping by an electron beam in the SIGE-1 experimental setup

    SciTech Connect

    Arlantsev, S. V., E-mail: arlantsev@mail.ru [Orlov Special Design Engineering Bureau of High-Energy Lasers 'Granat,' (Russian Federation); Kuz'min, G. P.; Minaev, I. M.; Mkheidze, G. P.; Tikhonevich, O. V.; Ul'yanov, D. K. [Russian Academy of Sciences, Prokhorov Institute of General Physics (Russian Federation)

    2011-12-15

    Lasers, sources of coherent UV and vacuum UV radiation, plasmachemical reactors, reactors for cleaning fouled gases, etc., can be classified as devices the working medium of which is plasma formed as a result of the interaction of a high-current relativistic electronic beam with gas. Efficiency of such devices which are united under the common name 'systems of injection gas electronics' (SIGE) depends mainly on the efficiency of energy transfer from a beam to gas ({eta}g = W{sub g}/W{sub b}) and that of the transform of the energy transferred to gas into the energy of the ultimate product W{sub in} ({eta}{sub in} = W{sub in}/W{sub g}). As a special case of SIGE, an experimental bench laser is considered. The new efficient method of pumping is supposed to be implemented on this laser to optimize the energy contribution {eta}{sub g} and useful output {eta}{sub in}.

  9. Investigation of stiffness and microstructure of joints soldered with gas-oxygen torch and infrared methods.

    PubMed

    Cheng, A C; Chai, J Y; Gilbert, J; Jameson, L M

    1994-07-01

    The stiffness of soldered connectors fabricated with the gas-oxygen torch technique was compared with those fabricated with the infrared technique. Untreated solder materials were used as controls. Untreated solder materials of gold-palladium, palladium-silver, and chromium-cobalt alloys exhibited significantly higher stiffness than the soldered specimens fabricated with either method. There was no significant difference between the gas-oxygen torch and the infrared groups of the gold-palladium and palladium-silver alloys. Photomicrographs revealed that the soldered specimens displayed porosities. For the chromium-cobalt alloy, the infrared group demonstrated significantly higher stiffness than the gas-oxygen torch group. Photomicrographs also disclosed that the chromium-cobalt alloy soldered with the gas-oxygen torch technique had a significant heat-affected zone. PMID:7916054

  10. Separation of sodium chloride from the evaporated residue of the reverse osmosis reject generated in the leather industry--optimization by response surface methodology.

    PubMed

    Boopathy, R; Sekaran, G

    2014-08-01

    Reverse osmosis (RO) concentrate is being evaporated by solar/thermal evaporators to meet zero liquid discharge standards. The resulted evaporated residue (ER) is contaminated with both organic and inorganic mixture of salts. The generation of ER is exceedingly huge in the leather industry, which is being collected and stored under the shelter to avoid groundwater contamination by the leachate. In the present investigation, a novel process for the separation of sodium chloride from ER was developed, to reduce the environmental impact on RO concentrate discharge. The sodium chloride was selectively separated by the reactive precipitation method using hydrogen chloride gas. The selected process variables were optimized for maximum yield ofNaCl from the ER (optimum conditions were pH, 8.0; temperature, 35 degrees C; concentration of ER, 600 g/L and HCl purging time, 3 min). The recovered NaCl purity was verified using a cyclic voltagramm. PMID:24956779

  11. A method to estimate weight and dimensions of aircraft gas turbine engines. Volume 1: Method of analysis

    NASA Technical Reports Server (NTRS)

    Pera, R. J.; Onat, E.; Klees, G. W.; Tjonneland, E.

    1977-01-01

    Weight and envelope dimensions of aircraft gas turbine engines are estimated within plus or minus 5% to 10% using a computer method based on correlations of component weight and design features of 29 data base engines. Rotating components are estimated by a preliminary design procedure where blade geometry, operating conditions, material properties, shaft speed, hub-tip ratio, etc., are the primary independent variables used. The development and justification of the method selected, the various methods of analysis, the use of the program, and a description of the input/output data are discussed.

  12. Method and apparatus for noble gas atom detection with isotopic selectivity

    DOEpatents

    Hurst, G. Samuel (Oak Ridge, TN); Payne, Marvin G. (Harriman, TN); Chen, Chung-Hsuan (Knoxville, TN); Parks, James E. (Oak Ridge, TN)

    1984-01-01

    Apparatus and methods of operation are described for determining, with isotopic selectivity, the number of noble gas atoms in a sample. The analysis is conducted within an evacuated chamber which can be isolated by a valve from a vacuum pumping system capable of producing a pressure of 10.sup.-8 Torr. Provision is made to pass pulses of laser beams through the chamber, these pulses having wavelengths appropriate for the resonance ionization of atoms of the noble gas under analysis. A mass filter within the chamber selects ions of a specific isotope of the noble gas, and means are provided to accelerate these selected ions sufficiently for implantation into a target. Specific types of targets are discussed. An electron measuring device produces a signal relatable to the number of ions implanted into the target and thus to the number of atoms of the selected isotope of the noble gas removed from the gas sample. The measurement can be continued until a substantial fraction, or all, of the atoms in the sample have been counted. Furthermore, additional embodiments of the apparatus are described for bunching the atoms of a noble gas for more rapid analysis, and for changing the target for repetitive cycling of the gas in the chamber. The number of repetitions of the cyclic steps depend upon the concentration of the isotope of interest, the separative efficiency of the mass filter, etc. The cycles are continued until a desired selectivity is achieved. Also described are components and a method of operation for a pre-enrichment operation for use when an introduction of a total sample would elevate the pressure within the chamber to levels in excess of those for operation of the mass filter, specifically a quadrupole mass filter. Specific examples of three noble gas isotope analyses are described.

  13. A New Method to Measure and Map the Gas Scale-Height of Disk Galaxies

    E-print Network

    Paolo Padoan; Sungeun Kim; Alyssa Goodman; Lister Staveley--Smith

    2001-03-15

    We propose a new method to measure and map the gas scale height of nearby disk galaxies. This method is applied successfully to the Australia Telescope Compact Array interferometric HI survey of the Large Magellanic Cloud (LMC); it could also be applied to a significant number of nearby disk galaxies, thanks to the next generation of interferometric facilities, such as the extended VLA and CARMA. The method consists of computing the Spectral Correlation Function (SCF) for a spectral-line map of a face-on galaxy. The SCF quantifies the correlation between spectra at different map positions as a function of their separation, and is sensitive to the properties of both the gas mass distribution and the gas velocity field. It is likely that spatial correlation properties of the gas density and velocity fields in a galactic disk are sensitive to the value of the scale height of the gas disk. A scale-free turbulent cascade is unlikely to extend to scales much larger than the disk scale height, as the disk dynamics on those larger scales should be dominated by two dimensional motions. We find a clear feature in the SCF of the LMC HI disk, on the scale of approximately 180 pc, which we identify as the disk scale height. We are also tentatively able to map variations of the scale height over the disk.

  14. [Research on the method of interference correction for nondispersive infrared multi-component gas analysis].

    PubMed

    Sun, You-Wen; Liu, Wen-Qing; Wang, Shi-Mei; Huang, Shu-Hua; Yu, Xiao-Man

    2011-10-01

    A method of interference correction for nondispersive infrared multi-component gas analysis was described. According to the successive integral gas absorption models and methods, the influence of temperature and air pressure on the integral line strengths and linetype was considered, and based on Lorentz detuning linetypes, the absorption cross sections and response coefficients of H2O, CO2, CO, and NO on each filter channel were obtained. The four dimension linear regression equations for interference correction were established by response coefficients, the absorption cross interference was corrected by solving the multi-dimensional linear regression equations, and after interference correction, the pure absorbance signal on each filter channel was only controlled by the corresponding target gas concentration. When the sample cell was filled with gas mixture with a certain concentration proportion of CO, NO and CO2, the pure absorbance after interference correction was used for concentration inversion, the inversion concentration error for CO2 is 2.0%, the inversion concentration error for CO is 1.6%, and the inversion concentration error for NO is 1.7%. Both the theory and experiment prove that the interference correction method proposed for NDIR multi-component gas analysis is feasible. PMID:22250543

  15. Evaporative cooling of flare plasma

    NASA Technical Reports Server (NTRS)

    Antiochos, S. K.; Sturrock, P. A.

    1978-01-01

    We investigate a one-dimensional loop model for the evaporative cooling of the coronal flare plasma. The important assumptions are that conductive losses dominate radiative cooling and that the evaporative velocities are small compared with the sound speed. We calculate the profile and evolution of the temperature and verify the accuracy of our assumptions for plasma parameters typical of flare regions. The model is in agreement with soft X-ray observations on the evolution of flare temperatures and emission measures. The effect of evaporation is to greatly reduce the conductive heat flux into the chromosphere and to enhance the EUV emission from the coronal flare plasma.

  16. Evaporative cooling of flare plasma

    NASA Technical Reports Server (NTRS)

    Antiochos, S. K.; Sturrock, P. A.

    1976-01-01

    A one-dimensional loop model for the evaporative cooling of the coronal flare plasma was investigated. Conductive losses dominated radiative cooling, and the evaporative velocities were small compared to the sound speed. The profile and evolution of the temperature were calculated. The model was in agreement with soft X-ray observations on the evolution of flare temperatures and emission measures. The effect of evaporation was to greatly reduce the conductive heat flux into the chromosphere and to enhance the EUV emission from the coronal flare plasma.

  17. Hollow-Fiber Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Bue, Grant; Trevino, Luis; Tsioulos, Gus; Mitchell, Keith; Settles, Joseph

    2013-01-01

    The hollow-fiber spacesuit water membrane evaporator (HoFi SWME) is being developed to perform the thermal control function for advanced spacesuits and spacecraft to take advantage of recent advances in micropore membrane technology in providing a robust, heat-rejection device that is less sensitive to contamination than is the sublimator. After recent contamination tests, a commercial-off-the-shelf (COTS) micro porous hollow-fiber membrane was selected for prototype development as the most suitable candidate among commercial hollow-fiber evaporator alternatives. An innovative design that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape, was developed into a full-scale prototype for the spacesuit application. Vacuum chamber testing has been performed to characterize heat rejection as a function of inlet water temperature and water vapor back-pressure, and to show contamination resistance to the constituents expected to be found in potable water produced by the wastewater reclamation distillation processes. Other tests showed tolerance to freezing and suitability to reject heat in a Mars pressure environment. In summary, HoFi SWME is a lightweight, compact evaporator for heat rejection in the spacesuit that is robust, contamination- insensitive, freeze-tolerant, and able to reject the required heat of spacewalks in microgravity, lunar, and Martian environments. The HoFi is packaged to reject 810 W of heat through 800 hours of use in a vacuum environment, and 370 W in a Mars environment. The device also eliminates free gas and dissolved gas from the coolant loop.

  18. Theoretical investigation of the injection and evaporation of water in a hydrogen/oxygen steam generator

    NASA Astrophysics Data System (ADS)

    Beer, Stefan

    1991-07-01

    Water is injected into the gas stream for the purpose of cooling the reaction products resulting from the stochiometric combustion of hydrogen with oxygen. The penetration of the jet decisively influences the temperature profile across the flow cross section in the water vapor. The penetration of the water jet into the stream is calculated using the jet shedding model and compared with the garden hose model. Models for the evaporation of water droplets in superheated steam are developed for calculating the evaporation paths. The parameters which influence the injection and evaporation process are subjected to variation and their effects in the evaporation paths are analyzed.

  19. Microfabricated gas sensor systems with sensitive nanocrystalline metal-oxide films

    Microsoft Academic Search

    M. Graf; A. Gurlo; N. Bârsan; U. Weimar; A. Hierlemann

    2006-01-01

    This article gives an overview on recent developments in metal-oxide-based gas sensor systems, in particular on nanocrystalline\\u000a oxide materials deposited on modern, state-of-the-art sensor platforms fabricated in microtechnology. First, metal-oxide-based\\u000a gas sensors are introduced, and the underlying principles and fundamentals of the gas sensing process are laid out. In the\\u000a second part, the different deposition methods, such as evaporation, sputtering,

  20. Method And Apparatus For Converting Hydrocarbon Fuel Into Hydrogen Gas And Carbon Dioxide

    DOEpatents

    Clawson, Lawrence G. (Dover, MA); Mitchell, William L. (Belmont, MA); Bentley, Jeffrey M. (Westford, MA); Thijssen, Johannes H. J. (Cambridge, MA)

    2001-03-27

    A hydrocarbon fuel reforming method is disclosed suitable for producing synthesis hydrogen gas from reactions with hydrocarbons fuels, oxygen, and steam. A first mixture of an oxygen-containing gas and a first fuel is directed into a first tube 108 to produce a first reaction reformate. A second mixture of steam and a second fuel is directed into a second tube 116 annularly disposed about the first tube 108 to produce a second reaction reformate. The first and second reaction reformates are then directed into a reforming zone 144 and subject to a catalytic reforming reaction. In another aspect of the method, a first fuel is combusted with an oxygen-containing gas in a first zone 108 to produce a reformate stream, while a second fuel under steam reforming in a second zone 116. Heat energy from the first zone 108 is transferred to the second zone 116.

  1. Infrared thermography of evaporative fluxes and dynamics of salt deposition on heterogeneous porous surfaces

    NASA Astrophysics Data System (ADS)

    Nachshon, Uri; Shahraeeni, Ebrahim; Or, Dani; Dragila, Maria; Weisbrod, Noam

    2011-12-01

    Evaporation of saline solutions from porous media, common in arid areas, involves complex interactions between mass transport, energy exchange and phase transitions. We quantified evaporation of saline solutions from heterogeneous sand columns under constant hydraulic boundary conditions to focus on effects of salt precipitation on evaporation dynamics. Mass loss measurements and infrared thermography were used to quantify evaporation rates. The latter method enables quantification of spatial and temporal variability of salt precipitation to identify its dynamic effects on evaporation. Evaporation from columns filled with texturally-contrasting sand using different salt solutions revealed preferential salt precipitation within the fine textured domains. Salt precipitation reduced evaporation rates from the fine textured regions by nearly an order of magnitude. In contrast, low evaporation rates from coarse-textured regions (due to low capillary drive) exhibited less salt precipitation and consequently less evaporation rate suppression. Experiments provided insights into two new phenomena: (1) a distinct increase in evaporation rate at the onset of evaporation; and (2) a vapor pumping mechanism related to the presence of a salt crust over semidry media. Both phenomena are related to local vapor pressure gradients established between pore water and the surface salt crust. Comparison of two salts: NaCl and NaI, which tend to precipitate above the matrix surface and within matrix pores, respectively, shows a much stronger influence of NaCl on evaporation rate suppression. This disparity reflects the limited effect of NaI precipitation on matrix resistivity for solution and vapor flows.

  2. Simulating evaporation from short-rotation forest: variations within and between seasons

    NASA Astrophysics Data System (ADS)

    Persson, Gunn; Lindroth, Anders

    1994-04-01

    A physically based soil water model was applied to a fertilized and irrigated short-rotation willow stand on a clay soil. The model is based on an extension of Richards' equation, and the water retention curve and saturated conductivity are determined by analyses of soil cores. The Penman-Monteith combination equation is used to calculate potential daily transpiration, soil evaporation and potential interception evaporation. Daily meteorological data are used as driving variables. Evaporation, estimated by the energy balance/Bowen ratio method, and soil-water tension measurements made over several years, were used to verify the model. Measured evaporation of water intercepted by the vegetation over 1 year was also compared with simulated monthly values. Good agreement was found between simulated evaporation and evaporation determined from Bowen ratio measurements. The cumulative seasonal evaporation exceeded the Penman open water evaporation by up to 31% in 3 years out of 4; it ranged between 416 and 584 mm for the period from May through October. On a mean seasonal basis, transpiration was 66%, soil evaporation 23% and interception evaporation 11% of total evaporation. The monthly interception evaporation comprised 5-23% of precipitation. The study period showed interannual variations attributable to variation in climate (including irrigation) as well as to stand age and development. This indicates that the model is quite general in many respects; it is tentatively suggested that it be used for accurate simulation of water balance components of short-rotation forest on a clay soil in this type of climate.

  3. 30 CFR 1206.174 - How do I value gas production when an index-based method cannot be used?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false How do I value gas production when an index-based method...ENFORCEMENT, DEPARTMENT OF THE INTERIOR Natural Resources Revenue PRODUCT VALUATION Indian Gas § 1206.174 How do I value gas production when an index-based...

  4. Evaporative cooling: effective latent heat of evaporation in relation to evaporation distance from the skin.

    PubMed

    Havenith, George; Bröde, Peter; den Hartog, Emiel; Kuklane, Kalev; Holmer, Ingvar; Rossi, Rene M; Richards, Mark; Farnworth, Brian; Wang, Xiaoxin

    2013-03-15

    Calculation of evaporative heat loss is essential to heat balance calculations. Despite recognition that the value for latent heat of evaporation, used in these calculations, may not always reflect the real cooling benefit to the body, only limited quantitative data on this is available, which has found little use in recent literature. In this experiment a thermal manikin, (MTNW, Seattle, WA) was used to determine the effective cooling power of moisture evaporation. The manikin measures both heat loss and mass loss independently, allowing a direct calculation of an effective latent heat of evaporation (?eff). The location of the evaporation was varied: from the skin or from the underwear or from the outerwear. Outerwear of different permeabilities was used, and different numbers of layers were used. Tests took place in 20°C, 0.5 m/s at different humidities and were performed both dry and with a wet layer, allowing the breakdown of heat loss in dry and evaporative components. For evaporation from the skin, ?eff is close to the theoretical value (2,430 J/g) but starts to drop when more clothing is worn, e.g., by 11% for underwear and permeable coverall. When evaporation is from the underwear, ?eff reduction is 28% wearing a permeable outer. When evaporation is from the outermost layer only, the reduction exceeds 62% (no base layer), increasing toward 80% with more layers between skin and wet outerwear. In semi- and impermeable outerwear, the added effect of condensation in the clothing opposes this effect. A general formula for the calculation of ?eff was developed. PMID:23329814

  5. Method of washing hydrogen sulfide from coke oven gas by the ammonium sulfide method

    SciTech Connect

    Ritter, H.

    1985-05-21

    An improved coke oven gas washing process for removing hydrogen sulfide is proposed wherein the coke oven gas is treated in a hydrogen sulfide scrubber by counterflow with an aqueous ammonia wash water. A stream of aqueous weak ammonia liquor is cooled and sprayed through nozzles in the mid-region of the hydrogen sulfide scrubber. A quantity of aqueous ammonia liquor, corresponding to the quantity which is sprayed through the said nozzles, is withdrawn from the hydrogen sulfide scrubber at a level below the nozzles and is introduced into the top of the said hydrogen sulfide scrubber. Ammonia vapor released at the nozzles has a higher partial pressure than the ammonia partial pressure of the coke oven gas in the region of the nozzle. The aqueous ammonia liquor from the deacidifier is the source of the cooled aqueous ammonia liquor which is introduced through the nozzles. A portion of the aqueous ammonia liquor from the deacidifier is introduced directly into the top of the hydrogen sulfide scrubber as a portion of the required aqueous ammonia wash water.

  6. Explosive evaporation in solar flares

    NASA Technical Reports Server (NTRS)

    Fisher, George H.

    1987-01-01

    This paper develops a simple analytical model for the phenomenon of 'explosive evaporation' driven by nonthermal electron heating in solar flares. The model relates the electron energy flux and spectrum, plus details of the preflare atmosphere, to the time scale for explosive evaporation to occur, the maximum pressure and temperature to be reached, rough estimates for the UV pulse emission flux and duration, and the evolution of the blueshifted component of the soft X-ray lines. An expression is given for the time scale for buildup to maximum pressures and the onset of rapid motion of the explosively evaporating plasma. This evaporation can excite a rapid response of UV line and continuum emission. The emission lines formed in the plasma approach a given emissivity-weighted blueshift speed.

  7. Dual manifold heat pipe evaporator

    DOEpatents

    Adkins, D.R.; Rawlinson, K.S.

    1994-01-04

    An improved evaporator section is described for a dual manifold heat pipe. Both the upper and lower manifolds can have surfaces exposed to the heat source which evaporate the working fluid. The tubes in the tube bank between the manifolds have openings in their lower extensions into the lower manifold to provide for the transport of evaporated working fluid from the lower manifold into the tubes and from there on into the upper manifold and on to the condenser portion of the heat pipe. A wick structure lining the inner walls of the evaporator tubes extends into both the upper and lower manifolds. At least some of the tubes also have overflow tubes contained within them to carry condensed working fluid from the upper manifold to pass to the lower without spilling down the inside walls of the tubes. 1 figure.

  8. Dual manifold heat pipe evaporator

    DOEpatents

    Adkins, Douglas R. (Albuquerque, NM); Rawlinson, K. Scott (Albuquerque, NM)

    1994-01-01

    An improved evaporator section for a dual manifold heat pipe. Both the upper and lower manifolds can have surfaces exposed to the heat source which evaporate the working fluid. The tubes in the tube bank between the manifolds have openings in their lower extensions into the lower manifold to provide for the transport of evaporated working fluid from the lower manifold into the tubes and from there on into the upper manifold and on to the condenser portion of the heat pipe. A wick structure lining the inner walls of the evaporator tubes extends into both the upper and lower manifolds. At least some of the tubes also have overflow tubes contained within them to carry condensed working fluid from the upper manifold to pass to the lower without spilling down the inside walls of the tubes.

  9. Evaporation Tower With Prill Nozzles

    NASA Technical Reports Server (NTRS)

    Du Fresne, E. R.

    1984-01-01

    Tower more efficient than conventional evaporation equipment. Liquids such as milk and fruit juice concentrated by passing them through tiny nozzle to form droplets, then allowing droplets to fall through evacuated tower with cooled walls.

  10. The desorptivity model of bulk soil-water evaporation

    NASA Technical Reports Server (NTRS)

    Clapp, R. B.

    1983-01-01

    Available models of bulk evaporation from a bare-surfaced soil are difficult to apply to field conditions where evaporation is complicated by two main factors: rate-limiting climatic conditions and redistribution of soil moisture following infiltration. Both factors are included in the "desorptivity model', wherein the evaporation rate during the second stage (the soil-limiting stage) of evaporation is related to the desorptivity parameter, A. Analytical approximations for A are presented. The approximations are independent of the surface soil moisture. However, calculations using the approximations indicate that both soil texture and soil moisture content at depth significantly affect A. Because the moisture content at depth decreases in time during redistribution, it follows that the A parameter also changes with time. Consequently, a method to calculate a representative value of A was developed. When applied to field data, the desorptivity model estimated cumulative evaporation well. The model is easy to calculate, but its usefulness is limited because it requires an independent estimate of the time of transition between the first and second stages of evaporation. The model shows that bulk evaporation after the transition to the second stage is largely independent of climatic conditions.

  11. Maximizing long-term gas industry profits in two minutes in Lotus using neural network methods

    Microsoft Academic Search

    P. J. Werbos

    1989-01-01

    Generalized methods, commonly used in neural network research, have made it possible for the Energy Information Adminstration (EIA) to solve a gas industry optimization problem on a personal computer that would previously have required a mainframe computer because of the run time required. The resulting model was used to produce EIA's official energy forecasts published in 1988. It is shown

  12. Method of purifying a gas stream using 1,2,3-triazolium ionic liquids

    DOEpatents

    Luebke, David; Nulwala, Hunald; Tang, Chau

    2014-12-09

    A method for separating a target gas from a gaseous mixture using 1,2,3-triazolium ionic liquids is presented. Industrial effluent streams may be cleaned by removing carbon dioxide from the stream by contacting the effluent stream with a 1,2,3-triazolium ionic liquid compound.

  13. Evaluation Method of Gas Turbine Blades Covering Integrity by IR Camera

    NASA Astrophysics Data System (ADS)

    Yang, Dong-Jo; Choi, Choul-Jun; Kim, Jae-Yeol

    Key parts of the main equipment in a gas turbine may likely be damaged due to operation under high temperature, high pressure, high-speed rotation, etc. Accordingly, the cost for maintenance increases and the damaged parts may cause generation to stop. The surface of a blade is thermal-sprayed, using powder with main compositions such as Ni, Cr, Al, etc, in order to inhibit hot oxidation. Conventional regular maintenance of the coating layer of a blade is made by FPI (Fluorescent Penetrant Inspection) and MTP (Magnetic Particle Testing). Such methods, however, are complicated and take a long time and also require high cost. In this study, defect diagnostics were tested on the coating layer of an industrial gas turbine blade, using an infrared thermography camera. Since the infrared thermography method can check a temperature distribution by means of non-contact on a wide range of areas, it can advantageously save expense and time as compared to conventional test methods. For the infrared thermography method, however, thermo-load must be applied onto a tested specimen and it is difficult to quantify the measured data. To solve the problems, this paper includes description about producing a specimen of a gas turbine blade (bucket), applying thermo-load onto the produced specimen, photographing thermography images by an infrared thermography camera, analyzing the thermography images, and pre-testing to analyze defects on the coating layer of the gas turbine blade.

  14. Study on prediction method for generation and consumption of coke oven gas

    Microsoft Academic Search

    Ying Liu; Jun Zhao; Wei Wang; Chun-yang Sheng; Li-qun Cong; Wei-min Feng

    2010-01-01

    A direct prediction method based on empirical mode decomposition and echo state network is proposed to predict coke oven gas generation and consumption of the steel industry. First, the empirical mode decomposition is used to de-noise the practical data with high noise level. Then the direct relationship between the prediction origin and prediction horizon using echo state network is established

  15. Method and apparatus for perforating at cutting with a solid fueled gas mixture

    Microsoft Academic Search

    A. J. Woytek; J. T. Lileck; E. J. Steigerwalt

    1984-01-01

    A method for cutting pipe casings and concrete liners or perforating the same and localized portions of surrounding strata in an earth bore is set forth wherein a gas phase cutting or perforating jet mixture of fluorine and nitrogen trifluoride is delivered to the cutting or perforation site from the decomposition of a solid, normally stable, perfluoroammonium salt. An appropriate

  16. Greenhouse gas emissions from swine effluent applied to soil by different methods.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Greenhouse gas (CO2, CH4, and N2O) emissions were measured from a field experiment evaluating pre-plant swine effluent application methods for no-till corn grain production. The treatments included a control, an inorganic fertilizer treatment receiving 179 kg N ha-1 as urea ammonium nitrate (UAN), ...

  17. Method and device for forming mixture gas in direct injection type internal combustion engine

    Microsoft Academic Search

    A. Saito; M. Yamada; K. Imai; K. Kawamura; M. Kimura

    1987-01-01

    A mixture gas formation method is described for a direct fuel injection type internal combustion engine having a piston with a recess forming a combustion space, air intake means with swirling means for swirling intake air to be supplied to the combustion space, and an intermittent type swirl injection nozzle having at least one tangential passage for swirling fuel, for

  18. Collaborative study on yeast activity, gas production (AACC Method 89-01)

    Microsoft Academic Search

    P Gélinas

    1997-01-01

    A method of the American Association of Cereal Chemists (AACC) for determining yeast activity (gas production) was tested in a collaborative study involving five laboratories. Samples of three different manufacturers for each of three yeast types (three active dry yeasts, three compressed yeasts, and three instant active dry yeasts) were duplicated and tested in three dough formulations mainly characterized by

  19. Cooling air recycling for gas turbine transition duct end frame and related method

    DOEpatents

    Cromer, Robert Harold (Johnstown, NY); Bechtel, William Theodore (Scotia, NY); Sutcu, Maz (Niskayuna, NY)

    2002-01-01

    A method of cooling a transition duct end frame in a gas turbine includes the steps of a) directing cooling air into the end frame from a region external of the transition duct and the impingement cooling sleeve; and b) redirecting the cooling air from the end frame into the annulus between the transition duct and the impingement cooling sleeve.

  20. Absolute detection of metastable rare gas atoms by a cw laser photoionization method

    Microsoft Academic Search

    S. Schohl; D. Klar; T. Kraft; H. A. J. Meijer; M.-W. Ruf; U. Schmitz; S. J. Smith; H. Hotop

    1991-01-01

    A novel, accurate method for the absolute detection of metastable rare gas atoms is described and demonstrated. It involves a direct in situ determination of the electron emission coefficient ? for impact of the respective metastable atom on a conducting surface. ? is reliably obtained by a cw two-photon ionization — depletion technique: the reduction ?IS in electron current from

  1. A rarefied gas dynamic numerical method applied to problems in statistical turbulence

    Microsoft Academic Search

    R. Srinivasan; D. P. Giddens; L. H. Bangert; J. C. Wu

    1979-01-01

    Lundgren's equation modeling the velocity probability distribution function for turbulence in a parallel flow closely resembles the BGK equation of kinetic theory. The turbulence equation has been solved numerically using a combination of finite differencing and discrete velocities, a method which has seen extensive service in the solution of rarefied gas dynamics problems. Several of the techniques and concepts of

  2. Method and apparatus for noble gas atom detection with isotopic selectivity

    Microsoft Academic Search

    G. Samuel Hurst; Marvin G. Payne; Chung-Hsuan Chen; James E. Parks

    1984-01-01

    Apparatus and methods of operation are described for determining, with isotopic selectivity, the number of noble gas atoms in a sample. The analysis is conducted within an evacuated chamber which can be isolated by a valve from a vacuum pumping system capable of producing a pressure of 10.sup.-8 Torr. Provision is made to pass pulses of laser beams through the

  3. Method and apparatus for noble gas atom detection with isotopic selectivity

    Microsoft Academic Search

    G. S. Hurst; M. G. Payne; C. H. Chen; J. E. Parks

    1984-01-01

    Apparatus and methods of operation are described for determining, with isotopic selectivity, the number of noble gas atoms in a sample. The analysis is conducted within an evacuated chamber which can be isolated by a valve from a vacuum pumping system capable of producing a pressure of 10[sup [minus]8] Torr. Provision is made to pass pulses of laser beams through

  4. Method Development for the Determination of Fluorotelomer Alcohols in Soils by Gas Chromatography Mass Spectrometry

    EPA Science Inventory

    Fluorotelomer alcohols (FTOHs) have been widely studied as precursors to perfluorocarboxylates, e.g. 8:2 FTOH degrades to perfluorooctanoic acid (PFOA). This presentation describes an analytical method for the extraction and analysis of 6:2, 8:2, and 10:2 FTOHs. Gas chromatograph...

  5. Hybrid Particle-Continuum Methods for Nonequilibrium Gas and Plasma Flows

    SciTech Connect

    Boyd, Iain D. [Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI (United States)

    2011-05-20

    Two different hybrid particle-continuum methods are described for simulation of nonequilibrium gas and plasma dynamics. The first technique, used for nonequilibrium hypersonic gas flows, uses either a continuum description or a particle method throughout a flow domain based on local conditions. This technique is successful in reproducing the results of full particle simulations at a small fraction of the cost. The second method uses a continuum model of the electrons combined with a particle description of the ions and atoms for simulating plasma jets. The physical accuracy of the method is assessed through comparisons with plasma plume measurements obtained in space. These examples illustrate that the complex physical phenomena associated with nonequilibrium conditions can be simulated with physical accuracy and numerical efficiency using such hybrid approaches.

  6. Removal of Sulfate Ion From AN107 by Evaporation

    Microsoft Academic Search

    GJ Lumetta; GS Klinger; DE Kurath; RL Sell; LP Darnell; LR Greenwood; CZ Soderquist; MJ Steele; MW Urie; JJ Wagner

    2000-01-01

    Hanford low-activity waste solutions contain sulfate, which can cause accelerated corrosion of the vitrification melter and unacceptable operating conditions. A method is needed to selectively separate sulfate from the waste. An experiment was conducted to evaluate evaporation for removing sulfate ion from Tank AN-107 low-activity waste. Two evaporation steps were performed. In the first step, the volume was reduced by

  7. Method for creating gas standards form liquid HFE-7100 and FC-72.

    SciTech Connect

    White, Michael K.; Brown, Jason R.; Thornberg, Steven Michael; Hochrein, James Michael; Irwin, Adriane Nadine

    2007-07-01

    HFE-7100 and FC-72 fluorinert are two fluids used during weapon component manufacturing. HFE-7100 is a solvent used in the cleaning of parts, and FC-72 is the blowing agent of a polymeric removable foam. The presence of either FC-72 or HFE-7100 gas in weapon components can provide valuable information as to the stability of the materials. Therefore, gas standards are needed so HFE-7100 and FC-72 gas concentrations can be accurately measured. There is no current established procedure for generating gas standards of either HFE-7100 or FC-72. This report outlines the development of a method to generate gas standards ranging in concentration from 0.1 ppm to 10% by volume. These standards were then run on a Jeol GC-Mate II mass spectrometer and analyzed to produce calibration curves. We present a manifold design that accurately generates gas standards of HFE-7100 and FC-72 and a procedure that allows the amount of each to be determined.

  8. Investigation on mercury removal method from flue gas in the presence of sulfur dioxide.

    PubMed

    Ma, Yongpeng; Qu, Zan; Xu, Haomiao; Wang, Wenhua; Yan, Naiqiang

    2014-08-30

    A new integrated process was developed for the removal and reclamation of mercury from the flue gas in the presence of SO2, typically derived from nonferrous metal smelting. The new process contains a pre-desulfurization unit (Stage I) and a co-absorption unit (Stage II). In Stage I, 90% of the SO2 from flue gas can be efficiently absorbed by ferric sulfate and reclaimed sulfuric acid. Meanwhile, the proportion of Hg(2+) and Hg(0) in the flue gas can be redistributed in this stage. Then, over 95% of the Hg(0) and the residual SO2 can be removed simultaneously with a composite absorption solution from the flue gas in Stage II, which is much more efficient for the Hg(0) reclaiming than the traditional method. The composite absorption solution in Stage II, which is composed of 0.1g/L HgSO4, 1.0% H2O2 and H2SO4, could effectively remove and reclaim Hg(0) overcoming the negative effect of SO2 on Hg(0) absorption. Moreover, the concentrations of HgSO4 and H2O2 were adjusted with the changes in of the concentrations of Hg(0) and SO2 in the flue gas. It is a potential and promising technology for the mercury removal and reclaim from the flue gas in the presence of SO2. PMID:25072135

  9. Dynamic analysis of evaporator characteristics

    Microsoft Academic Search

    Jae-Dol Kim; Jung-In Yoon; Hag-Geun Ku

    1997-01-01

    An analysis of the dynamic characteristics in an evaporator was numerically performed for control and design of the refrigeration\\u000a and air conditioning systems. The important factors, such as refrigerant flow rate, inlet enthalpy, inlet air velocity and\\u000a air temperature, are incorporated with this analysis. An evaporator is modeled for the dynamic characteristics analysis separated\\u000a into three regions which are the

  10. Digitally Programmable Micro Evaporation Source for Nanofabrication

    NASA Astrophysics Data System (ADS)

    Han, Han; Imboden, Matthias; Del Corro, Pablo; Stark, Thomas; Lally, Richard; Pardo, Flavio; Bolle, Cris; Bishop, David

    2015-03-01

    There is a significant world-wide effort to develop nano-manufacturing methods that can extend into the deep nanoscale region, below 20 nm. Techniques include photolithography, nano-imprint and direct write methods such as dip-pen lithography and atomic calligraphy. A central component of any fabrication setup is the deposition control of the materials to be used. Here we present a MEMS based, multi-material evaporation source array with each source element consisting of a polysilicon plate suspended by two electrical constriction leads. When resistively heating the plate, the pre-loaded material is thermally evaporated off of the plate. By arranging many of these devices into an array, one has a multi-material, digitally programmable evaporation source. Pulsing the source with precisely controlled peak voltage and timing can emit atom fluxes with an unprecedented level of control in terms of what, when and how many atoms get deposited. By varying their dimensions and arrangement, the source array can provide controllable atom fluxes ranging over ten orders of magnitude. Such a material source can provide precise control and flexibility when conducting nanopatterning and nanolithography.

  11. Determination of bromopropylate in grapes by gas chromatography: evaluation of two analytical methods

    Microsoft Academic Search

    Themistokles D. Lekkas; Anastasia D. Nikolaou

    2006-01-01

    Two gas chromatography methods were developed for the determination of the acaricide bromopropylate in grapes. The first included chromatographic separation with a DB-1 column and electron capture detection (GC-ECD), while the second utilized chromatographic separation with a DB-5MS column and mass spectrometry detection (GC-MSD). Sample preparation was the same for both methods and included liquid–liquid extraction with dichloromethane and diethylether,

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  13. Method for generating a highly reactive plasma for exhaust gas aftertreatment and enhanced catalyst reactivity

    DOEpatents

    Whealton, John H. (Oak Ridge, TN); Hanson, Gregory R. (Clinton, TN); Storey, John M. (Oak Ridge, TN); Raridon, Richard J. (Oak Ridge, TN); Armfield, Jeffrey S. (Upsilanti, MI); Bigelow, Timothy S. (Knoxville, TN); Graves, Ronald L. (Knoxville, TN)

    2001-01-01

    A method for non-thermal plasma aftertreatment of exhaust gases the method comprising the steps of providing short risetime (about 40 ps), high frequency (about 5G hz), high power bursts of low-duty factor microwaves sufficient to generate a dielectric barrier discharge and passing a gas to treated through the discharge so as to cause dissociative reduction of the exhaust gases. The invention also includes a reactor for generating the non-thermal plasma.

  14. Gas leak location method for pressurized cable networks using pattern matching

    Microsoft Academic Search

    Kazutoki Takeda

    1995-01-01

    A new gas leak location method is proposed for telecommunication cable networks which are composed of different cables and\\/or branch cables. With this method, falling pressure curves are measured at several pressure measuring points, and the pressure curves are calculated using a simulation. The position and\\/or size of the leak are varied in the simulation and when the measured falling-pressure

  15. The quantity analysis method research of oil and gas geo-anomaly information mining

    Microsoft Academic Search

    Li Qing; Liu Suhong; Zhao Xiang; Wang Peijuan

    2003-01-01

    During oil-gas exploration, much information is collected concerning geo-physical exploration, geo-chemical exploration, remote-sensing and geology exploration. Depending on the traditional exploration methods, it is difficult to make further progress with the deep step in oil exploration, so new theories and methods are urgently needed. Geo-anomaly theory was first put forward by Zhao Pengda, a Chinese math geologist, in 1991. It

  16. Laser Heterodyne Method for High-Resolution Gas-Density Measurements

    Microsoft Academic Search

    M. Volkan Ötügen; Biswa Ganguly

    2001-01-01

    A new method for noncontact, high-resolution measurement of gas density is described. The method uses a two-frequency Zeeman-split He -Ne laser and cumulative phase-measuring electronics. The measurement is resolved in two dimensions and provides density that is averaged only along the length of the laser beam that passes through the test section. The technique is based on highly accurate measurement

  17. Exhaust gas recirculation control method and apparatus for internal combustion engine

    SciTech Connect

    Tsutsumi, K.

    1987-02-10

    An exhaust gas recirculation control method is described for operating an exhaust gas recirculation control device including a needle valve provided in an exhaust gas recirculation passage for setting an effective diameter of the passage, a position sensor for providing a signal representing a position of the needle valve, and a negative pressure motor for positioning the needle valve. The method comprises: setting a target value for the needle valve according to predetermined operating conditions of the internal combustion engine; measuring a positional deviation between the target value and an actual position of the needle valve as represented by the signal provided by the position sensor; and driving the negative pressure motor with only a single drive pulse having a time width corresponding to the measured positional deviation. An exhaust gas recirculation control apparatus is described for operating an exhaust gas recirculation control device. The apparatus comprises: means for setting a target value for the needle valve according to predetermined operating conditions of the internal combustion engine; and means for measuring a positional deviation between the target value and an actual position of the needle valve as represented by the signal provided by the position sensor.

  18. CaO-MgO-Al 2o 3-SiO 2 liquids: chemical and isotopic effects of Mg and Si evaporation in a closed system of solar composition

    NASA Astrophysics Data System (ADS)

    Grossman, L.; Fedkin, A. V.

    2003-11-01

    A method is shown for calculating vapor pressures over a CMAS droplet in a gas of any composition. It is applied to the problem of the evolution of the chemical and Mg and Si isotopic composition of a completely molten droplet having the composition of a likely refractory inclusion precursor during its evaporation into the complementary, i.e. modified solar, gas from which it originally condensed, a more realistic model than previous calculations in which the ambient gas is pure H 2(g). Because the loss rate of Mg is greater than that of Si, the vapor pressure of Mg (g) falls and its ambient pressure rises faster than those of SiO (g) during isothermal evaporation, causing the flux of Mg (g) to approach zero faster and MgO to approach its equilibrium concentration sooner than SiO 2. As time passes, ? 25Mg and ? 29Si increase in the droplet and decrease in the ambient gas. The net flux of each isotope crossing the droplet/gas interface is the difference between its outgoing and incoming flux. ? 25Mg and ? 29Si of this instantaneous gas become higher, first overtaking their values in the ambient gas, causing them to increase with time, and later overtaking their values in the droplet itself, causing them to decrease with time, ultimately reaching their equilibrium values. If the system is cooling during evaporation and if mass transfer ceases at the solidus temperature, 1500 K, final MgO and SiO 2 contents of the droplet are slightly higher in modified solar gas than in pure H 2(g), and the difference increases with decreasing cooling rate and increasing ambient pressure. During cooling under some conditions, net fluxes of evaporating species become negative, causing reversal of the evaporation process into a condensation process, an increase in the MgO and/or SiO 2 content of the droplet with time, and an increase in their final concentrations with increasing ambient pressure and/or dust/gas ratio. At cooling rates <˜3 K/h, closed-system evaporation at Ptot ˜ 10 -3 bar in a modified solar gas, or at lower pressure in systems with enhanced dust/gas ratio, can yield the same ? 25Mg in a residual CMAS droplet for vastly different evaporated fractions of Mg. The ? 25Mg of a refractory residue may thus be insufficient to determine the extent of Mg loss from its precursor. Evaporation of Mg into an Mg-bearing ambient gas causes ? 26Mg and ? 25Mg of the residual droplet to fall below values expected from Rayleigh fractionation for the amount of 24Mg evaporated, with the degree of departure increasing with increasing fraction evaporated and ambient pressure of Mg. ? 26Mg and ? 25Mg do not depart proportionately from Rayleigh fractionation curves, with ? 25Mg being less than expected on the basis of ? 26Mg by up to ˜1.2‰. Such departures from Rayleigh fractionation could be used in principle to distinguish heavily from lightly evaporated residues with the same ? 25Mg.

  19. Method of measurement of VOCs in the off-gas and wastewater of wastewater treatment plants

    SciTech Connect

    Min Wang; Keener, T.C.; Orton, T.L.; Zhu, H.; Bishop, P.; Pekonen, S. [Univ. of Cincinnati, OH (United States). Dept. of Civil and Environmental Engineering; Siddiqui, K. [Hamilton County Metropolitan Sewer District, Cincinnati, OH (United States)

    1997-12-31

    VOCs need to be controlled according to Title 3 of the 1990 Clean Air Act Amendments (CAAA), so an accurate estimation of the total VOC emissions must be attained. This paper reports on a study where EPA method 624 was revised so that this method could be used for VOC analysis both in the water and off-gas of wastewater treatment plants. The revised method uses the same approach and equipment as water and soil analyses, thereby providing a great time and cost advantage for anyone needing to perform this type of analysis. Without using a cryogenic preconcentration step, gas samples from Tedlar bags are easily analyzed to concentrations of approximately 20 ppb using scan mode in a GC-MS unit. For the wastewater, scan mode was still used for the identification, but Selected Ion Monitoring (SIM) mode was used for quantitative analysis because of lower VOC concentration in the water. The results show that this method`s detection limit (MDL) was lowered 2--3 orders of magnitude when compared with scan mode. The modified method has been successfully applied to the identification and quantitative analysis of wastewater and off-gas VOCs from a publicly owned treatment works (POTW) aeration basin (120 MGD).

  20. Method for controlling the heat load of a plant fed with natural gas of variable calorific value and density

    SciTech Connect

    Beltrami, G.; Formica, F.

    1984-12-18

    A method and apparatus for controlling the heat load in a plant fed with natural gas of variable calorific value and density consisting of withdrawing a portion of gas from the feed line, burning it in a special combustion chamber, withdrawing the combustion products from the chamber, determining the quantity of free oxygen contained in the dry burnt gas and varying the volumetric throughput of the natural gas on the main line.

  1. Modelling sub-daily evaporation from a small reservoir.

    NASA Astrophysics Data System (ADS)

    McGloin, Ryan; McGowan, Hamish; McJannet, David; Burn, Stewart

    2013-04-01

    Accurate quantification of evaporation from small water storages is essential for water management and is also required as input in some regional hydrological and meteorological models. Global estimates of the number of small storages or lakes (< 0.1 kilometers) are estimated to be in the order of 300 million (Downing et al., 2006). However, direct evaporation measurements at small reservoirs using the eddy covariance or scintillometry techniques have been limited due to their expensive and complex nature. To correctly represent the effect that small water bodies have on the regional hydrometeorology, reliable estimates of sub-daily evaporation are necessary. However, evaporation modelling studies at small reservoirs have so far been limited to quantifying daily estimates. In order to ascertain suitable methods for accurately modelling hourly evaporation from a small reservoir, this study compares evaporation results measured by the eddy covariance method at a small reservoir in southeast Queensland, Australia, to results from several modelling approaches using both over-water and land-based meteorological measurements. Accurate predictions of hourly evaporation were obtained by a simple theoretical mass transfer model requiring only over-water measurements of wind speed, humidity and water surface temperature. An evaporation model that was recently developed for use in small reservoir environments by Granger and Hedstrom (2011), appeared to overestimate the impact stability had on evaporation. While evaporation predictions made by the 1-dimensional hydrodynamics model, DYRESM (Dynamic Reservoir Simulation Model) (Imberger and Patterson, 1981), showed reasonable agreement with measured values. DYRESM did not show any substantial improvement in evaporation prediction when inflows and out flows were included and only a slighter better correlation was shown when over-water meteorological measurements were used in place of land-based measurements. Downing, J. A., Y. T. Prairie, J. J. Cole, C. M. Duarte, L. J. Tranvik, R. G. Striegl, W. H. McDowell, P. Kortelainen, N. F. Caraco, J. M. Melack and J. J. Middelburg (2006), The global abundance and size distribution of lakes, ponds, and impoundments, Limnology and Oceanography, 51, 2388-2397. Granger, R.J. and N. Hedstrom (2011), Modelling hourly rates of evaporation from small lakes, Hydrological and Earth System Sciences, 15, doi:10.5194/hess-15-267-2011. Imberger, J. and J.C. Patterson (1981), Dynamic Reservoir Simulation Model - DYRESM: 5, In: Transport Models for Inland and Coastal Waters. H.B. Fischer (Ed.). Academic Press, New York, 310-361.

  2. Evaporation of pure liquid sessile and spherical suspended drops: a review.

    PubMed

    Erbil, H Yildirim

    2012-01-15

    A sessile drop is an isolated drop which has been deposited on a solid substrate where the wetted area is limited by a contact line and characterized by contact angle, contact radius and drop height. Diffusion-controlled evaporation of a sessile drop in an ambient gas is an important topic of interest because it plays a crucial role in many scientific applications such as controlling the deposition of particles on solid surfaces, in ink-jet printing, spraying of pesticides, micro/nano material fabrication, thin film coatings, biochemical assays, drop wise cooling, deposition of DNA/RNA micro-arrays, and manufacture of novel optical and electronic materials in the last decades. This paper presents a review of the published articles for a period of approximately 120 years related to the evaporation of both sessile drops and nearly spherical droplets suspended from thin fibers. After presenting a brief history of the subject, we discuss the basic theory comprising evaporation of micrometer and millimeter sized spherical drops, self cooling on the drop surface and evaporation rate of sessile drops on solids. The effects of drop cooling, resultant lateral evaporative flux and Marangoni flows on evaporation rate are also discussed. This review also has some special topics such as drop evaporation on superhydrophobic surfaces, determination of the receding contact angle from drop evaporation, substrate thermal conductivity effect on drop evaporation and the rate evaporation of water in liquid marbles. PMID:22277832

  3. Catalyst for selective conversion of synthesis gas and method of making the catalyst

    DOEpatents

    Dyer, Paul N. (Allentown, PA); Pierantozzi, Ronald (Macungie, PA)

    1986-01-01

    A Fischer-Tropsch (F-T) catalyst, a method of making the catalyst and an F-T process utilizing the catalyst by which synthesis gas, particularly carbon-monoxide rich synthesis gas is selectively converted to higher hydrocarbons of relatively narrow carbon number range. In general, the selective and notably stable catalyst, consists of an inert carrier first treated with a Group IV B metal compound (such as zirconium or titanium), preferably an alkoxide compound, and subsequently treated with an organic compound of an F-T metal catalyst, such as cobalt, iron or ruthenium carbonyl. Reactions with air and water and calcination are specifically avoided in the catalyst preparation procedure.

  4. Method for Making Measurements of the Post-Combustion Residence Time in a Gas Turbine Engine

    NASA Technical Reports Server (NTRS)

    Miles, Jeffrey H (Inventor)

    2015-01-01

    A system and method of measuring a residence time in a gas-turbine engine is provided, whereby the method includes placing pressure sensors at a combustor entrance and at a turbine exit of the gas-turbine engine and measuring a combustor pressure at the combustor entrance and a turbine exit pressure at the turbine exit. The method further includes computing cross-spectrum functions between a combustor pressure sensor signal from the measured combustor pressure and a turbine exit pressure sensor signal from the measured turbine exit pressure, applying a linear curve fit to the cross-spectrum functions, and computing a post-combustion residence time from the linear curve fit.

  5. Vapor pressure measurements on low-volatility terpenoid compounds by the concatenated gas saturation method.

    PubMed

    Widegren, Jason A; Bruno, Thomas J

    2010-01-01

    The atmospheric oxidation of monoterpenes plays a central role in the formation of secondary organic aerosols (SOAs), which have important effects on the weather and climate. However, models of SOA formation have large uncertainties. One reason for this is that SOA formation depends directly on the vapor pressures of the monoterpene oxidation products, but few vapor pressures have been reported for these compounds. As a result, models of SOA formation have had to rely on estimated values of vapor pressure. To alleviate this problem, we have developed the concatenated gas saturation method, which is a simple, reliable, high-throughput method for measuring the vapor pressures of low-volatility compounds. The concatenated gas saturation method represents a significant advance over traditional gas saturation methods. Instead of a single saturator and trap, the concatenated method uses several pairs of saturators and traps linked in series. Consequently, several measurements of vapor pressure can be made simultaneously, which greatly increases the rate of data collection. It also allows for the simultaneous measurement of a control compound, which is important for ensuring data quality. In this paper we demonstrate the use of the concatenated gas saturation method by determination of the vapor pressures of five monoterpene oxidation products and n-tetradecane (the control compound) over the temperature range 283.15-313.15 K. Over this temperature range, the vapor pressures ranged from about 0.5 Pa to about 70 Pa. The standard molar enthalpies of vaporization or sublimation were determined by use of the Clausius-Clapeyron equation. PMID:20000397

  6. Evaporation of mercury impurity from liquid lead-bismuth eutectic

    NASA Astrophysics Data System (ADS)

    Aerts, A.; Danaci, S.; Gonzalez Prieto, B.; Van den Bosch, J.; Neuhausen, J.

    2014-05-01

    The equilibrium evaporation of mercury from dilute solutions in liquid lead-bismuth eutectic (LBE) was studied in argon atmosphere. Mercury present as impurity in LBE was evaporated and detected by atomic fluorescence spectroscopy. A method which could accurately simulate the experimental data was developed. Coefficients of the Henry constant temperature correlation for mercury dissolved in LBE were determined. Experiments with samples from several different batches of LBE revealed that mercury at mole fractions between 10-6 and 10-12 and temperatures between 150 and 350 °C evaporated from liquid LBE close to ideal behavior. Evaporation of mercury from solid LBE on the other hand was unexpectedly high. These results are important for safety evaluations of LBE based spallation targets and accelerator driven systems.

  7. Removal of Sulfate Ion From AN-107 by Evaporation

    SciTech Connect

    GJ Lumetta; GS Klinger; DE Kurath; RL Sell; LP Darnell; LR Greenwood; CZ Soderquist; MJ Steele; MW Urie; JJ Wagner

    2000-08-02

    Hanford low-activity waste solutions contain sulfate, which can cause accelerated corrosion of the vitrification melter and unacceptable operating conditions. A method is needed to selectively separate sulfate from the waste. An experiment was conducted to evaluate evaporation for removing sulfate ion from Tank AN-107 low-activity waste. Two evaporation steps were performed. In the first step, the volume was reduced by 55% while in the second step, the liquid volume was reduced another 22%. Analysis of the solids precipitated during these evaporations revealed that large amounts of sodium nitrate and nitrite co-precipitated with sodium sulfate. Many other waste components precipitated as well. It can be concluded that sulfate removal by precipitation is not selective, and thus, evaporation is not a viable option for removing sulfate from the AN-107 liquid.

  8. Building micro-soccer-balls with evaporating colloidal fakir drops

    NASA Astrophysics Data System (ADS)

    Gelderblom, Hanneke; Marín, Álvaro G.; Susarrey-Arce, Arturo; van Housselt, Arie; Lefferts, Leon; Gardeniers, Han; Lohse, Detlef; Snoeijer, Jacco H.

    2013-11-01

    Drop evaporation can be used to self-assemble particles into three-dimensional microstructures on a scale where direct manipulation is impossible. We present a unique method to create highly-ordered colloidal microstructures in which we can control the amount of particles and their packing fraction. To this end, we evaporate colloidal dispersion drops from a special type of superhydrophobic microstructured surface, on which the drop remains in Cassie-Baxter state during the entire evaporative process. The remainders of the drop consist of a massive spherical cluster of the microspheres, with diameters ranging from a few tens up to several hundreds of microns. We present scaling arguments to show how the final particle packing fraction of these balls depends on the drop evaporation dynamics, particle size, and number of particles in the system.

  9. Building micro-soccer-balls with evaporating colloidal fakir drops

    E-print Network

    Alvaro G. Marin; Arturo Susarrey-Arce; Hanneke Gelderblom; Arie van Houselt; Leon Lefferts; Han Gardeniers; Detlef Lohse; Jacco Snoeijer

    2012-03-20

    Evaporation-driven particle self-assembly can be used to generate three-dimensional microstructures. We present a new method to create these colloidal microstructures, in which we can control the amount of particles and their packing fraction. To this end, we evaporate colloidal dispersion droplets on a special type of superhydrophobic micro-structured surface, on which the droplet re- mains in Cassie-Baxter state during the entire evaporative process. The remainders of the droplet consist of a massive spherical cluster of the microspheres, with diameters ranging from a few tens up to several hundreds of microns. We present scaling arguments to show how the final particle packing fraction of these balls depends on the dynamics of the droplet evaporation.

  10. Building micro-soccer-balls with evaporating colloidal fakir drops

    E-print Network

    Marin, Alvaro G; Gelderblom, Hanneke; van Houselt, Arie; Lefferts, Leon; Gardeniers, Han; Lohse, Detlef; Snoeijer, Jacco

    2012-01-01

    Evaporation-driven particle self-assembly can be used to generate three-dimensional microstructures. We present a new method to create these colloidal microstructures, in which we can control the amount of particles and their packing fraction. To this end, we evaporate colloidal dispersion droplets on a special type of superhydrophobic micro-structured surface, on which the droplet re- mains in Cassie-Baxter state during the entire evaporative process. The remainders of the droplet consist of a massive spherical cluster of the microspheres, with diameters ranging from a few tens up to several hundreds of microns. We present scaling arguments to show how the final particle packing fraction of these balls depends on the dynamics of the droplet evaporation.

  11. Changes in the Composition of Aromatherapeutic Citrus Oils during Evaporation.

    PubMed

    Francis, George W; Bui, Yen Thuy Hoang

    2015-01-01

    The composition of some commercial Citrus oils, lemon, sweet orange, and tangerine, designated for aromatherapy, was examined before and after partial evaporation in a stream of nitrogen. The intact oils contained the expected mixtures of mono- and sesquiterpenes, with hydrocarbons dominating and lesser amounts of oxygenated analogues making up the remainder. Gas chromatography-mass spectrometry was used to follow alterations in the relative amounts of the various components present as evaporation proceeded. Changes were marked, and in particular more volatile components present in the intact oils rapidly disappeared. Thus the balance of content was shifted away from monoterpene hydrocarbons towards the analogous alcohols and carbonyl compounds. The results of this differential evaporation are discussed and possible consequences for aromatherapy use are noted. The case of lemon oil was especially interesting as the relative amount of citral, a known sensitizer, remaining as time elapsed represented an increasing percentage of the total oil. PMID:26161120

  12. Changes in the Composition of Aromatherapeutic Citrus Oils during Evaporation

    PubMed Central

    Francis, George W.; Bui, Yen Thuy Hoang

    2015-01-01

    The composition of some commercial Citrus oils, lemon, sweet orange, and tangerine, designated for aromatherapy, was examined before and after partial evaporation in a stream of nitrogen. The intact oils contained the expected mixtures of mono- and sesquiterpenes, with hydrocarbons dominating and lesser amounts of oxygenated analogues making up the remainder. Gas chromatography-mass spectrometry was used to follow alterations in the relative amounts of the various components present as evaporation proceeded. Changes were marked, and in particular more volatile components present in the intact oils rapidly disappeared. Thus the balance of content was shifted away from monoterpene hydrocarbons towards the analogous alcohols and carbonyl compounds. The results of this differential evaporation are discussed and possible consequences for aromatherapy use are noted. The case of lemon oil was especially interesting as the relative amount of citral, a known sensitizer, remaining as time elapsed represented an increasing percentage of the total oil. PMID:26161120

  13. Development of a Direct Evaporator for the Organic Rankine Cycle

    SciTech Connect

    Donna Post Guillen; Helge Klockow; Matthew Lehar; Sebastian Freund; Jennifer Jackson

    2011-02-01

    This paper describes research and development currently underway to place the evaporator of an Organic Rankine Cycle (ORC) system directly in the path of a hot exhaust stream produced by a gas turbine engine. The main goal of this research effort is to improve cycle efficiency and cost by eliminating the usual secondary heat transfer loop. The project’s technical objective is to eliminate the pumps, heat exchangers and all other added cost and complexity of the secondary loop by developing an evaporator that resides in the waste heat stream, yet virtually eliminates the risk of a working fluid leakage into the gaseous exhaust stream. The research team comprised of Idaho National Laboratory and General Electric Company engineers leverages previous research in advanced ORC technology to develop a new direct evaporator design that will reduce the ORC system cost by up to 15%, enabling the rapid adoption of ORCs for waste heat recovery.

  14. Decision Matrix Screening Tool to Identify the Best Artificial Lift Method for Liquid-loaded Gas Wells 

    E-print Network

    Soponsakulkaew, Nitsupon

    2010-10-12

    Liquid loading is a serious problem in gas wells. Many proven artificial lift methods have been used to alleviate this problem. However, a complete workflow to determine the most suitable artificial lift method for given ...

  15. Evaluation of oxygen transfer efficiency under process conditions using the dynamic off-gas method.

    PubMed

    Schuchardt, A; Libra, J A; Sahlmann, C; Wiesmann, U; Gnirss, R

    2007-05-01

    The off-gas method can be used to investigate standard oxygen transfer efficiencies under process conditions (alphaSOTE) over the operating life of an aeration system. A method to evaluate alphaSOTE is described in detail by US and German standards. The standards, however, do not describe how to evaluate dynamic changes in aSOTE over a day, which can be useful to uncover problems and unfavourable process conditions. Based on over three years experience gained in off-gas testing in Berlin wastewater treatment plants (WWTPs) under operating conditions, a method to evaluate and interpret the dynamic changes in oxygen transfer is presented. The application of the dynamic off-gas method brings important additional information, which can be used to increase operational efficiency of the aeration basin and to increase process reliability, with a relatively small increase in effort. This paper shows how to perform dynamic measurements under process conditions. Some results of such measurements under dynamic process conditions, performed in a Berlin WWTP, are discussed. PMID:17615957

  16. Ion Surfing: A new ion transport method for cryogenic gas catchers, simulations

    NASA Astrophysics Data System (ADS)

    Gehring, Amanda; Bollen, Georg; Brodeur, Maxime; Morrissey, Dave; Pang, Gregory

    2011-10-01

    Gas cells are the tool of choice to thermalize fast rare ion beams produced at projectile fragmentation facilities. After passing through solid degraders, the residual kinetic energy of the ions is dissipated through collisions with the gas atoms and ionization. Previously, ions were directed through a gas cell along a descending electrostatic potential gradient called a ``drag field.'' Some cells apply a drag field over electrodes with alternating (RF) fields to prevent the rare ions from colliding with the walls. ``Ion surfing'' is a new method proposed by Bollen which replaces the drag field with a traveling wave superimposed with RF on numerous, thin electrodes. Large potential differences are no longer required for transport over long distances, and the traveling wave can transport ions at a greater speed. This method is being tested for the new cryogenic linear gas cell of the National Superconducting Cyclotron Laboratory at Michigan State University. We will present the concept and simulation results. Work supported by the National Science Foundation and Department of Energy.

  17. Salt stains from evaporating droplets

    PubMed Central

    Shahidzadeh, Noushine; Schut, Marthe F. L.; Desarnaud, Julie; Prat, Marc; Bonn, Daniel

    2015-01-01

    The study of the behavior of sessile droplets on solid substrates is not only associated with common everyday phenomena, such as the coffee stain effect, limescale deposits on our bathroom walls , but also very important in many applications such as purification of pharmaceuticals, de-icing of airplanes, inkjet printing and coating applications. In many of these processes, a phase change happens within the drop because of solvent evaporation, temperature changes or chemical reactions, which consequently lead to liquid to solid transitions in the droplets. Here we show that crystallization patterns of evaporating of water drops containing dissolved salts are different from the stains reported for evaporating colloidal suspensions. This happens because during the solvent evaporation, the salts crystallize and grow during the drying. Our results show that the patterns of the resulting salt crystal stains are mainly governed by wetting properties of the emerging crystal as well as the pathway of nucleation and growth, and are independent of the evaporation rate and thermal conductivity of the substrates. PMID:26012481

  18. Salt stains from evaporating droplets.

    PubMed

    Shahidzadeh, Noushine; Schut, Marthe F L; Desarnaud, Julie; Prat, Marc; Bonn, Daniel

    2015-01-01

    The study of the behavior of sessile droplets on solid substrates is not only associated with common everyday phenomena, such as the coffee stain effect, limescale deposits on our bathroom walls , but also very important in many applications such as purification of pharmaceuticals, de-icing of airplanes, inkjet printing and coating applications. In many of these processes, a phase change happens within the drop because of solvent evaporation, temperature changes or chemical reactions, which consequently lead to liquid to solid transitions in the droplets. Here we show that crystallization patterns of evaporating of water drops containing dissolved salts are different from the stains reported for evaporating colloidal suspensions. This happens because during the solvent evaporation, the salts crystallize and grow during the drying. Our results show that the patterns of the resulting salt crystal stains are mainly governed by wetting properties of the emerging crystal as well as the pathway of nucleation and growth, and are independent of the evaporation rate and thermal conductivity of the substrates. PMID:26012481

  19. Spatial analysis of evaporation in a small catchment

    NASA Astrophysics Data System (ADS)

    Hogan, Patrick; Broer, Martine; Blöschl, Günther

    2013-04-01

    Evaporation is one of the most important processes in describing the land surface- atmosphere interactions since it connects the energy and water balances. Knowledge of the spatial variations in evaporation allows us to better estimate runoff generation processes and crop yields as well as improve regional water balances at a larger scale. However much is still unknown about quantifying evaporation over non-uniform surfaces due to the non-linearity of the evaporation process. The purpose of this project is to measure the spatial distribution of evaporation using a variety of micro-meteorological techniques over a heterogeneous land surface in our 64Ha experimental HOAL catchment at Petzenkirchen for a period of three years. The land use in the catchment is 87% arable land, 5% pasture, 6% forest and 2% paved surfaces with the main crops grown being winter wheat and maize. In the catchment the following micro-meteorological measurement devices are already present; an open and closed path eddy-correlation system, a Bowen ratio system and a surface layer scintillometer. The scintillometer and the open path gas analyser will be moved throughout the catchment to capture as much of the heterogeneity of the catchment as possible using the sensor footprints. The catchment is also instrumented with a soil moisture content network and a detailed monitoring network of discharge measurements of the stream that flows through the catchment. This research will focus on minimizing and resolving measurement differences associated with the use of different devices and studying the evaporation distribution. The measured data will be applied to hydrological models at the same scale as the catchment and then at larger scales in combination with remote sensing data to test whether knowledge of the small scale patterns of evaporation can be upscaled. The spatial and also temporal data will be used to study land-atmosphere interactions using the optimality based transpiration models of Schymanski et al (2009) and Cowen & Farquhar (1977).

  20. Oscillation of Molten Pool by Pulsed Assist Gas Oscillating Method and Penetration Control Using Peculiar Frequency

    NASA Astrophysics Data System (ADS)

    Jianbin, Ju; Hasegawa, Hiroyuki; Suga, Yasuo

    In automatic butt welding of relatively thin plates, it is important to control welding conditions in order to obtain a sound full penetration weld. Recently, it was reported that there was an intimate relationship between the oscillation of the molten pool and penetration. Therefore, the oscillation phenomena of the weld molten pool were analyzed and the estimation of penetration by detecting frequency of the molten pool was attempted. In this study, a new oscillating method, Pulsed Assist Gas (PAG) oscillating method is proposed. The natural frequency of molten pool was measured from the molten pool oscillation detected by arc sensor. A control system, which controled welding current on the basis of oscillation frequency measured, was constructed. Main results obtained are summarized as follows: 1) In order to oscillate molten pool during TIG arc welding of thin steel plate, Pulsed Assist Gas (PAG) oscillating method was proposed and effectiveness of this method was confirmed. 2) The PAG oscillating method was superior to conventional pulsed current oscillating (PC) method in amplitude of oscillation and robustness of frequency measurement. 3) Applying PAG oscillating method and detecting oscillation of arc voltage, the peculiar frequency of the oscillation of molten pool could be detected. 4) A system to control weld penetration using the principle of detecting the peculiar frequency of the molten pool was constructed and the effectiveness of the system was demonstrated.