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1

Leachate evaporation using landfill gas  

Microsoft Academic Search

This paper describes a century-old technology with a new twist of using landfill gas as a fuel in an evaporation system. The system is designed to help landfills reduce the cost of leachate disposal while also destroying VOC emissions in an enclosed flare.

T. M. White; V. M. Grace; W. Freivald

1996-01-01

2

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)

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.

Miller, R. S.; Bellan, J.

1997-01-01

3

Apparatus and method for evaporator defrosting  

DOEpatents

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.

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

2001-01-01

4

Evaporation in equilibrium, in vacuum, and in hydrogen gas  

NASA Technical Reports Server (NTRS)

Evaporation experiments were conducted for SiO2 in three different conditions: in equilibrium, in vacuum, and in hydrogen gas. Evaporation rate in vacuum is about two orders of magnitude smaller than that in equilibrium, which is consistent with previous works. The rate in hydrogen gas changes depending on hydrogen pressure. The rate at 10 exp -7 bar of hydrogen pressure is as small as that of free evaporation, but at 10 exp -5 bar of hydrogen pressure it is larger than that in equilibrium. In equilibrium and in vacuum, the evaporation rate is limited by decomposition of SiO2 on the crystal surface, but it is limited by a diffusion process for evaporation in hydrogen gas. Therefore, evaporation rate of minerals in the solar nebula can be shown neither by that in equilibrium nor by that in vacuum. The maximum temperature of the solar nebula at the midplane at 2-3 AU where chondrites are believed to have originated is calculated to be as low as 150 K, 1500 K, or in between them. The temperature is, in any case, not high enough for total evaporation of the interstellar materials. Therefore, evaporation of interstellar materials is one of the most important processes for the origin and fractionation of solid materials. The fundamental process of evaporation of minerals has been intensively studied for these several years. Those experiments were carried out either in equilibrium or in vacuum; however, evaporation in the solar nebula is in hydrogen (and much smaller amount of helium) gas. In order to investigate evaporation rate and compositional (including isotopic) fractionation during evaporation, vaporization experiments for various minerals in various conditions are conducted. At first, SiO2 was adopted for a starting material, because thermochemical data and its nature of congruent vaporization are well known. Experiments were carried out in a vacuum furnace system.

Nagahara, Hiroko

1993-01-01

5

Isothermal evaporation of ethanol in a dynamic gas atmosphere.  

PubMed

Optimization of evaporation and pyrolysis conditions for ethanol are important in carbon nanotube (CNT) synthesis. The activation enthalpy (?H(‡)), the activation entropy (?S(‡)), and the free energy barrier (?G(‡)) to evaporation have been determined by measuring the molar coefficient of evaporation, k(evap), at nine different temperatures (30-70 °C) and four gas flow rates (25-200 mL/min) using nitrogen and argon as carrier gases. At 70 °C in argon, the effect of the gas flow rate on k(evap) and ?G(‡) is small. However, this is not true at temperatures as low as 30 °C, where the increase of the gas flow rate from 25 to 200 mL/min results in a nearly 6 times increase of k(evap) and decrease of ?G(‡) by ~5 kJ/mol. Therefore, at 30 °C, the effect of the gas flow rate on the ethanol evaporation rate is attributed to interactions of ethanol with argon molecules. This is supported by simultaneous infrared spectroscopic analysis of the evolved vapors, which demonstrates the presence of different amounts of linear and cyclic hydrogen bonded ethanol aggregates. While the amount of these aggregates at 30 °C depends upon the gas flow rate, no such dependence was observed during evaporation at 70 °C. When the evaporation was carried out in nitrogen, ?G(‡) was almost independent of the evaporation temperature (30-70 °C) and the gas flow rate (25-200 mL/min). Thus the evaporation of ethanol in a dynamic gas atmosphere at different temperatures may go via different mechanisms depending on the nature of the carrier gas. PMID:22136647

Milev, Adriyan S; Wilson, Michael A; Kannangara, G S Kamali; Feng, Hai; Newman, Phillip A

2012-01-12

6

Evaporation and condensation in a polyatomic Knudsen gas  

Microsoft Academic Search

Based upon the scattering law and reciprocity, the evaporation coefficient and accommondation coefficients characterizing the interface heat and mass transfer of a polyatomic gas are defined. The particle flux and the heat flux through a polyatomic Knudsen gas between parallel surfaces are found to be the solutions of two Fredholm integral equations. A Neumann series leads to Onsager's reciprocity relations

H. Lang

1981-01-01

7

Evaporation  

NSDL National Science Digital Library

The representation is an animation of the water cycle. It shows water evaporating from a large body of water with a descriptive text describing the water cycle process including evaporation, condensation and precipitation. An additional diagram on transport is included.

8

Regulatory Off-Gas Analysis from the Evaporation of Hanford Simulated Waste Spiked with Organic Compounds  

SciTech Connect

After strontium/transuranics removal by precipitation followed by cesium/technetium removal by ion exchange, remaining low activity waste in the Hanford River Protection Project Waste Treatment Plant is to be concentrated by evaporation prior to being mixed with glass formers and vitrified. To provide a technical basis to permit the waste treatment facility, a relatively organic-rich Hanford Tank 241-AN-107 waste simulant was spiked with 14 target volatile, semi-volatile and pesticide compounds, and evaporated under vacuum in a bench-scale natural circulation evaporator fitted with an industrial stack off-gas sampler at the Savannah River Technology Center. An evaporator material balance for the target organics was calculated by combining liquid stream mass and analytical data with off-gas emissions estimates obtained using EPA SW-846 Methods. Volatile and light semi-volatile organic compounds in the waste simulant were found to largely exit through the condenser vent, while heavier semi-volatiles and pesticides generally remain in the evaporator concentrate. An OLI Environmental Simulation Program evaporator model successfully predicted operating conditions and the experimental distribution of the fed target organics exiting in the concentrate, condensate and off-gas streams with the exception of a few semi-volatile and pesticide compounds. Comparison with Henry's Law predictions suggests the OLI ESP model is constrained by available literature data.

Calloway, T.B. Jr.

2003-10-23

9

Thermal Evaporation of Gas from X-ray Clusters  

E-print Network

A fraction of the thermal protons in the outer envelope of an X-ray cluster have velocities that exceed the local escape speed from the cluster gravitational potential. The Coulomb mean-free-path of these protons is larger than the virial radius of the cluster at temperatures >2.5 keV. The resulting leakage of suprathermal particles generates a collisionless shock in neighboring voids and fills them with heat and magnetic fields. The momentum flux of suprathermal particles cannot be confined by magnetic tension at the typical field strength in the periphery of cluster halos (evaporation could drain up to a tenth of the cluster gas at its virial temperature. The evaporated fraction could increase dramatically if additional heat is deposited into the gas by cluster mergers, active galactic nuclei or supernovae. Thermal evaporation is not included in existing cosmological simulations since they are based on the fluid approximation. Measurements of the baryon mass fraction in the outer envelopes of hot clusters (through their Sunyaev-Zel'dovich effect or X-ray emission) can be used to empirically constrain their evaporation rate.

Abraham Loeb

2006-06-22

10

Simplified evaporation method for determining soil hydraulic properties  

Microsoft Academic Search

Summary Evaporation experiments are commonly used to derive hydraulic properties of soils. In the simplified evaporation method, as proposed by Schindler (Schindler, U., 1980. Ein Schnellverfahren zur Messung der Wasserleitfahigkeit im teilgesattigten Boden an Ste- chzylinderproben. Arch. Acker- u. Pflanzenbau u. Bodenkd. Berlin 24, 1-7), the weight of a soil sample and pressure heads at two height levels are recorded

A. Peters; W. Durner

2008-01-01

11

Evaporation Correction Methods for Microwave Retrievals of Surface Precipitation Rate  

Microsoft Academic Search

Active and passive microwave remote sensing esti- mates of surface precipitation based on signals from hydrometeors aloft require correction for evaporated precipitation that would otherwise reach the ground. This paper develops and compares two near-surface evaporation correction methods using two years of data from 509 globally distributed rain gauges and three passive millimeter-wave Advanced Microwave Sounding Units (AMSUs) aboard National

Chinnawat Surussavadee; David H. Staelin

2011-01-01

12

Multilayer composite material and method for evaporative cooling  

NASA Technical Reports Server (NTRS)

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.

Buckley, Theresa M. (Inventor)

2002-01-01

13

COMPONENT LOSS DURING EVAPORATION-RECONSTITUTION OF ORGANIC ENVIRONMENTAL SAMPLES FOR GAS CHROMATOGRAPHIC ANALYSIS  

EPA Science Inventory

Standard and sample solutions stored in borosilicate sample vials were allowed to evaporate to dryness at room temperature. The solutions were analyzed by gas chromatography-flame ionization detection before evaporation and after reconstitution to the original volume to determine...

14

Chemical Potential Jump During Evaporation of a Bose Gas with Variable Molecular Collision Frequency  

NASA Astrophysics Data System (ADS)

Evaporation of a binary mixture is considered for the case when the evaporating component is a Bose gas. An analytical solution of the problem of the chemical potential jump of a Bose gas is obtained for the case when the molecular collision frequency of the evaporating component is a variable quantity. The dependence of the coefficient of the chemical potential jump on the evaporation coefficient is investigated. The concentration of the evaporating component is assumed to be much less than that of the carrier gas. A graphical study of the coefficient of the chemical potential jump is presented.

Bedrikova, E. A.; Latyshev, A. V.

2014-09-01

15

Method of determining kinetic boundary conditions in net evaporation/condensation  

NASA Astrophysics Data System (ADS)

The aim of the present study is to develop the method of determining the kinetic boundary condition (KBC) at a vapor-liquid interface in net evaporation/condensation. We proposed a novel method for determining the KBC by combining the numerical simulations of the mean field kinetic theory and the molecular gas dynamics. The method was evaluated on steady vapor flow between two liquid slabs at different temperatures. A uniform net mass flux in the vapor phase induced by net evaporation and condensation is obtained from the numerical simulation of the mean field kinetic theory for both vapor and liquid phases. The KBC was specified by using the uniform net mass flux, and the numerical simulation of the molecular gas dynamics was conducted for the vapor phase. Comparing the macroscopic variables in the vapor phase obtained from both numerical simulations, we can validate the KBC whether the appropriate solutions are obtained. Moreover, the evaporation and condensation coefficients were estimated uniquely. The results showed that the condensation and evaporation coefficients were identical and constant in net evaporation. On the other hand, in net condensation, the condensation coefficient increased with the collision molecular mass flux. We also presented the applicable limit of the KBC which is assumed to be the isotropic Gaussian distribution at the liquid temperature. From these results, the KBCs in net evaporation and condensation, which enable the exact macroscopic variables to be determined, were proposed.

Kon, Misaki; Kobayashi, Kazumichi; Watanabe, Masao

2014-07-01

16

Method and apparatus for flash evaporation of liquids  

DOEpatents

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.

Bharathan, Desikan (Lakewood, CO)

1984-01-01

17

DEPOSITION OF ELECTRON BEAM EVAPORANT IN A LOW VACUUM GAS FLOW ENVIRONMENT  

E-print Network

1 DEPOSITION OF ELECTRON BEAM EVAPORANT IN A LOW VACUUM GAS FLOW ENVIRONMENT J.F. Groves, H seed layers for semiconductor interconnects [5]). In other instances vapor phase syn- thesized films-beam) evaporant in a low vacuum gas flow environment. The chapter will show how understanding of the technology

Wadley, Haydn

18

Evaporation and Condensation of Large Droplets in the Presence of Inert Admixtures Containing Soluble Gas  

E-print Network

­liquid interface taking into account the effect of nonisothermal gas absorption. It is demonstrated of evaporation of droplets in the flowing or stagnant gases were discussed in numerous theoretical

Elperin, Tov

19

Preparation of drug nanoparticles by emulsion evaporation method  

NASA Astrophysics Data System (ADS)

Polymeric drug nanoparticles were prepared by emulsion solvent evaporation method. In this study, prepared the polymeric drug nanoparticles consist of ketoprofen and Eudragit E 100. The morphology structure was investigated by scanning electron microscopy (SEM). The interactions between the drug and polymer were investigated by Fourier transform infrared spectroscopy (FTIR). The size distribution was measured by means of Dynamic Light Scattering. The nanoparticles have an average size of about 150 nm. The incorporation ability of drugs in the polymeric nanoparticles depended on the integration between polymer and drug as well as the glass transition temperature of the polymer.

Hoa, Le Thi Mai; Chi, Nguyen Tai; Triet, Nguyen Minh; Thanh Nhan, Le Ngoc; Mau Chien, Dang

2009-09-01

20

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

SciTech Connect

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.

TERRI, FELLINGER

2004-12-21

21

Regulatory Off-Gas Analysis from the Evaporation of Hanford Simulated Waste Spiked with Organic Compounds  

SciTech Connect

The purposes of this work were to: (1) develop preliminary operating data such as expected concentration endpoints for flow sheet development and evaporator design, and (2) examine the regulatory off-gas emission impacts from the evaporation of relatively organic-rich Hanford Tank 241-AN-107 Envelope C waste simulant containing 14 volatile, semi-volatile and pesticide organic compounds potentially present in actual Hanford RPP waste.

Saito, H.H.

2001-03-28

22

Methods of gas analysis  

SciTech Connect

Methods for sampling, calibrating, and analyzing for helium, impurities in helium, and natural gases are described. These methods were developed by the US Bureau of Mines to assist in the processing of natural gas for helium recovery. 35 refs.

Emerson, D.E. (Bureau of Mines, Amarillo, TX (United States))

1993-01-01

23

An evaporation estimation method based on the coupled 2-D turbulent heat and vapor transport equations  

E-print Network

An evaporation estimation method based on the coupled 2-D turbulent heat and vapor transport conditions and constant energy available at the evaporating surface yields a simple equation (i.e., the wet data, monthly, warm-season evaporation rates were estimated for five rectangular regions across

Szilagyi, Jozsef

24

Electron Beam Evaporation of Tungsten Oxide Films for Gas Sensors  

Microsoft Academic Search

Pure and iron incorporated nanostructured Tungsten Oxide (WO3) thin films were investigated for gas sensing applications using noise spectroscopy. The WO3 sensor was able to detect lower concentrations (1-10 ppm) of NH3, CO, CH4, and Acetaldehyde gases at operating temperatures between 100°C to 250°C. The iron-doped Tungsten Oxide sensor ( WO3:Fe) showed some response to Acetaldehyde gas at relatively higher

T. Tesfamichael

2010-01-01

25

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

USGS Publications Warehouse

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.

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

2003-01-01

26

[Measurement and estimation methods and research progress of snow evaporation in forests].  

PubMed

Accurate measurement and estimation of snow evaporation (sublimation) in forests is one of the important issues to the understanding of snow surface energy and water balance, and it is also an essential part of regional hydrological and climate models. This paper summarized the measurement and estimation methods of snow evaporation in forests, and made a comprehensive applicability evaluation, including mass-balance methods (snow water equivalent method, comparative measurements of snowfall and through-snowfall, snow evaporation pan, lysimeter, weighing of cut tree, weighing interception on crown, and gamma-ray attenuation technique) and micrometeorological methods (Bowen-ratio energy-balance method, Penman combination equation, aerodynamics method, surface temperature technique and eddy covariance method). Also this paper reviewed the progress of snow evaporation in different forests and its influencal factors. At last, combining the deficiency of past research, an outlook for snow evaporation rearch in forests was presented, hoping to provide a reference for related research in the future. PMID:24697085

Li, Hui-Dong; Guan, De-Xin; Jin, Chang-Jie; Wang, An-Zhi; Yuan, Feng-Hui; Wu, Jia-Bing

2013-12-01

27

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

NASA Astrophysics Data System (ADS)

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.

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

28

Fuel oil evaporation in swirling hot gas streams  

Microsoft Academic Search

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

Baifang Zuo; E. Van Den Bulck

1998-01-01

29

A comparative STM study of Ru nanoparticles deposited on HOPG by mass-selected gas aggregation versus thermal evaporation  

NASA Astrophysics Data System (ADS)

Scanning tunneling microscopy was used to compare the morphologies of Ru nanoparticles deposited onto highly-oriented graphite surfaces using two different physical vapour deposition methods; (1) pre-formed mass-selected Ru nanoparticles with diameters between 2 nm and 15 nm were soft-landed onto HOPG surfaces using a gas-aggregation source and (2) nanoparticles were formed by e-beam evaporation of Ru films onto HOPG. The particles generated by the gas-aggregation source are round in shape with evidence of facets resolved on the larger particles. Annealing these nanoparticles when they are supported on unsputtered HOPG resulted in the sintering of smaller nanoparticles, while larger particles remained immobile. Nanoparticles deposited onto sputtered HOPG surfaces were found to be stable against sintering when annealed. The size and shape of nanoparticles deposited by e-beam evaporation depend to a large extent on the state of the graphite support and the temperature. Ru deposition onto unsputtered HOPG is characterised by bimodal growth with large flat particles formed on the substrate terraces and smaller diameter particles aligned along the substrate steps. Evaporation onto sputtered HOPG results in the formation of 2 nm round particles with a narrow size distribution. Finally, thermal deposition onto both sputtered and unsputtered HOPG at 660 °C results in larger particles showing a flat Ru(0 0 0 1) top facet.

Nielsen, R. M.; Murphy, S.; Strebel, C.; Johansson, M.; Nielsen, J. H.; Chorkendorff, I.

2009-12-01

30

Evaporation and heating of a single suspended coal-water slurry droplet in hot gas streams  

SciTech Connect

The evaporation, heating, and burning of single coal-water slurry droplets are studied. The coal selected in this study is Pittsburgh Seam number 8 coal which is a medium volatile caking bituminous coal. The droplet is suspended on a microthermocouple and exposed to a hot gas stream. Temperature measurement and microscopic observation are performed in the parametric studies. The duration of water evaporation in CWS droplets decreases with the reduction of the droplet size, increasing of coal weight fraction, and increasing of gas temperature and velocity. The duration of heat-up is always significant due to the agglomeration. The CWS droplets are generally observed to swell like popcorn during heating. A model for the formation of the popped swelling is proposed and discussed.

Shi-chune, Y.; Liu, L.

1982-01-01

31

Growth of fullerene nanoparticles prepared by the gas-evaporation technique  

Microsoft Academic Search

C60 and C70 fullerene nanoparticles prepared by evaporating their powders in inert gas were investigated by electron microscopy and X-ray diffraction. Crystal structures of the particles were face centred cubic (fcc) which is a stable phase at high temperature, with lattice parameters of a=1.42 nm for C60 and a=1.499 nm for C70. Nanoparticles with definite crystal habits were sometimes observed

T. Ohno; S. Yatsuya

1998-01-01

32

Evaporation model for beam based additive manufacturing using free surface lattice Boltzmann methods  

NASA Astrophysics Data System (ADS)

Evaporation plays an important role in many technical applications including beam-based additive manufacturing processes, such as selective electron beam or selective laser melting (SEBM/SLM). In this paper, we describe an evaporation model which we employ within the framework of a two-dimensional free surface lattice Boltzmann method. With this method, we solve the hydrodynamics as well as thermodynamics of the molten material taking into account the mass and energy losses due to evaporation and the recoil pressure acting on the melt pool. Validation of the numerical model is performed by measuring maximum melt depths and evaporative losses in samples of pure titanium and Ti-6Al-4V molten by an electron beam. Finally, the model is applied to create processing maps for an SEBM process. The results predict that the penetration depth of the electron beam, which is a function of the acceleration voltage, has a significant influence on evaporation effects.

Klassen, Alexander; Scharowsky, Thorsten; Körner, Carolin

2014-07-01

33

Numerical simulation and field test study of desulfurization wastewater evaporation treatment through flue gas.  

PubMed

Aimed at cost saving and pollution reduction, a novel desulfurization wastewater evaporation treatment system (DWETS) for handling wet flue gas desulfurization (WFGD) wastewater of a coal-fired power plant was studied. The system's advantages include simple process, and less investment and space. The feasibility of this system has been proven and the appropriate position and number of nozzles, the spray droplet size and flue gas temperature limitation have been obtained by computational fluid dynamics (CFD) simulation. The simulation results show that a longer duct, smaller diameter and higher flue gas temperature could help to increase the evaporation rate. The optimal DWETS design of Shangdu plant is 100 ?m droplet sprayed by two nozzles located at the long duct when the flue gas temperature is 130 °C. Field tests were carried out based on the simulation results. The effects of running DWETS on the downstream devices have been studied. The results show that DWETS has a positive impact on ash removal efficiency and does not have any negative impact on the electrostatic precipitator (ESP), flue gas heat exchanger and WFGD. The pH values of the slurry of WFGD slightly increase when the DWETS is running. The simulation and field test of the DWETS show that it is a feasible future technology for desulfurization wastewater treatment. PMID:25325555

Deng, Jia-Jia; Pan, Liang-Ming; Chen, De-Qi; Dong, Yu-Quan; Wang, Cheng-Mu; Liu, Hang; Kang, Mei-Qiang

2014-01-01

34

Instabilities in a horizontal liquid layer in cocurrent gas flow with an evaporating interface  

NASA Astrophysics Data System (ADS)

The problem of a two-layer system consisting of a horizontal liquid layer in contact with its own vapor is considered. The liquid layer is bounded by a rigid wall from below, and phase change can occur at the interface. The flow of the vapor phase is driven by a constant pressure gradient in the streamwise direction. We have taken into account the effects of buoyancy, thermocapillarity, evaporation, and the dynamics of the vapor phase. A full linear stability analysis is performed using a Chebyshev spectral method. The influences of evaporation effect and the interfacial shear on the Rayleigh instability and the Marangoni instability have been studied. The results show that both the evaporation and the interfacial shear play important roles in the stability of the system.

Liu, R.; Kabov, O. A.

2012-06-01

35

Analysis of bubble rise using the VOF method. 2: Bubble interactions, wall effects and evaporation  

SciTech Connect

The motion of single and multiple gas bubbles in an otherwise stationary liquid contained in a closed, right vertical cylinder is investigated using a modified Volume-of-Fluid (VOF) method incorporating surface tension stresses. The theoretical background and the motion of an isolated bubble was considered in a separate paper (Chen et al., 1996) where the initial bubble radius was small compared to that of the cylinder and wall-effects were negligible. In this work, the focus is on the interference effects during the motion of two initially spherical bubbles in a gravitational field, as well as the influence of the container wall on the bubble motion: the initial bubble diameter in the present study is more than half the cylinder diameter. The bubble size is also much larger than that required to satisfy the condition in which the gas can be treated as incompressible. In addition, the effect on bubble motion of the inclusion of evaporation at the gas-liquid interface is considered.

Chen, L.; Leonardi, E. [Univ. of New South Wales, Sydney, New South Wales (Australia). School of Mechanical and Manufacturing Engineering; Reizes, J.A. [Univ. of Technology, Sydney, New South Wales (Australia); Garimella, S.V. [Univ. of Wisconsin, Milwaukee, WI (United States). Dept. of Mechanical Engineering

1996-12-31

36

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

PubMed

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

Visser, G H; Schekkerman, H

1999-01-01

37

Gas flaring method and apparatus  

Microsoft Academic Search

This patent describes a method of flaring a gas mixture formed in a landfill. It comprises: withdrawing said gas mixture from said landfill; conducting said gas mixture to an annular burner comprised of an annular channel having sides and a bottom and a continuous top structure having a plurality of elongated flow passages therein configured such that said gas mixture

M. R. Keller; R. K. Noble; D. W. Pressnall

1990-01-01

38

Method of dehydrating natural gas  

Microsoft Academic Search

A method for dehydration of natural gas is provided wherein well head gas is supplied to a three-phase inlet separator, the vapor mixture of natural gas and water removed from that inlet separator means is supplied to a turboexpander, and the resulting refrigerated mixture of natural gas and condensed water vapor is supplied to a multi-phase outlet separator. The turboexpander

1985-01-01

39

Method for liquifying natural gas  

Microsoft Academic Search

A method for liquefying natural gas comprises heat exchanging a pressurized natural gas with two independent coolant circuits. The first coolant circuit pre-cools the compressed natural gas. After the natural gas is pre-cooled in the first circuit, a major portion is liquefied in heat exchange with the coolant in the second circuit while the remaining minor portion is liquefied in

Forg

1980-01-01

40

Evaporation kinetics in the hanging drop method of protein crystal growth  

NASA Technical Reports Server (NTRS)

An engineering analysis of the rate of evaporation of solvent in the hanging drop method of protein crystal growth is presented; these results are applied to 18 different drop and well arrangements commonly encountered in the laboratory, taking into account the chemical nature of the salt, the drop size and shape, the drop concentration, the well size, the well concentration, and the temperature. It is found that the rate of evaporation increases with temperature, drop size, and with the salt concentration difference between the drop and the well. The evaporation possesses no unique half-life. Once the salt in the drop achieves about 80 percent of its final concentration, further evaporation suffers from the law of diminishing returns.

Baird, James K.; Frieden, Richard W.; Meehan, E. J., Jr.; Twigg, Pamela J.; Howard, Sandra B.; Fowlis, William A.

1987-01-01

41

A hybrid method for refrigerant flow balancing in multi-circuit evaporators: Upstream versus downstream flow control  

Microsoft Academic Search

A hybrid method for optimizing refrigerant distribution in evaporators is presented that involves the use of small balancing valves in each circuit along with a primary expansion device to control the overall superheat from the evaporator. The flow balancing valves could be located upstream or downstream of the evaporator. This paper presents the results of a study to investigate the

Jun-Hyeung Kim; James E. Braun; Eckhard A. Groll

2009-01-01

42

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

E-print Network

in laser evaporation methods John H. Callahana , Marsha C. Galiciab , Akos Vertesb,* a Naval Research of Chemistry, George Washington University, Washington, DC 20052, USA Abstract Laser evaporation techniques, including matrix-assisted pulsed laser evaporation (MAPLE), are attracting increasing attention due

Vertes, Akos

43

Nanoparticle thin films for gas sensors prepared by matrix assisted pulsed laser evaporation.  

PubMed

The matrix assisted pulsed laser evaporation (MAPLE) technique has been used for the deposition of metal dioxide (TiO(2), SnO(2)) nanoparticle thin films for gas sensor applications. For this purpose, colloidal metal dioxide nanoparticles were diluted in volatile solvents, the solution was frozen at the liquid nitrogen temperature and irradiated with a pulsed excimer laser. The dioxide nanoparticles were deposited on Si and Al(2)O(3) substrates. A rather uniform distribution of TiO(2) nanoparticles with an average size of about 10 nm and of SnO(2) nanoparticles with an average size of about 3 nm was obtained, as demonstrated by high resolution scanning electron microscopy (SEM-FEG) inspections. Gas-sensing devices based on the resistive transduction mechanism were fabricated by depositing the nanoparticle thin films onto suitable rough alumina substrates equipped with interdigitated electrical contacts and heating elements. Electrical characterization measurements were carried out in controlled environment. The results of the gas-sensing tests towards low concentrations of ethanol and acetone vapors are reported. Typical gas sensor parameters (gas responses, response/recovery time, sensitivity, and low detection limit) towards ethanol and acetone are presented. PMID:22574039

Caricato, Anna Paola; Luches, Armando; Rella, Roberto

2009-01-01

44

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

USGS Publications Warehouse

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 (BREB) method, considered the standard. Values from the Priestley-Taylor, deBruin-Keijman, and Penman methods compared most favorably with BREB-determined values. Differences from BREB values averaged 0.19, 0.27, and 0.20 mm d-1, respectively, and results were within 20% of BREB values during more than 90% of the 37 monthly comparison periods. All three methods require measurement of net radiation, air temperature, change in heat stored in the lake, and vapor pressure, making them relatively data intensive. Several of the methods had substantial bias when compared with BREB values and were subsequently modified to eliminate bias. Methods that rely only on measurement of air temperature, or air temperature and solar radiation, were relatively cost-effective options for measuring evaporation at this small New England lake, outperforming some methods that require measurement of a greater number of variables. It is likely that the atmosphere above Mirror Lake was affected by occasional formation of separation eddies on the lee side of nearby high terrain, although those influences do not appear to be significant to measured evaporation from the lake when averaged over monthly periods. ?? 2007 Elsevier B.V. All rights reserved.

Rosenberry, D. O.; Winter, T. C.; Buso, D. C.; Likens, G. E.

2007-01-01

45

Bifurcation of a Flow of a Gas between Rotating Coaxial Circular Cylinders with Evaporation and Condensation II  

NASA Astrophysics Data System (ADS)

A gas between rotating coaxial circular cylinders made of the condensed phase of the gas, where evaporation or condensation takes place is considered. The time-independent behavior of the gas is studied analytically with special interest in bifurcation of the solution in the following situation, where ``the incompressible Navier-Stokes set of equations'' is derived from the Boltzmann equation: (i) the Knudsen number is vanishingly small; (ii) the speeds of rotation of the cylinders are small and the Mach number of the gas flow is the same order as the Knudsen number (or the Reynolds number of the flow is of the order of unity); and (iii) the temperature difference of the cylinders is small (or the difference normalized by the mean temperature is of the order of the Knudsen number). The analysis is carried out with the asymptotic theory of the Boltzmann system by Sone & Aoki (1987). The bifurcation of solution from the axially symmetric and uniform solution is studied by a standard perturbation method. The relation of the parameters in the problem where the bifurcation occurs (bifurcation point) and the behavior of the solution in the neighborhood of the bifurcation point are obtained.

Sone, Yoshio; Doi, Toshiyuki

2001-11-01

46

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

Microsoft Academic Search

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

Dennis D. Baldocchi; Tilden P. Meyers

1991-01-01

47

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

SciTech Connect

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.

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

2003-05-12

48

Gas flaring method and apparatus  

SciTech Connect

This patent describes a method of flaring a gas mixture formed in a landfill. It comprises: withdrawing said gas mixture from said landfill; conducting said gas mixture to an annular burner comprised of an annular channel having sides and a bottom and a continuous top structure having a plurality of elongated flow passages therein configured such that said gas mixture can flow through said passages but the backward propagation of flame therethrough at low pressure and low or static flow rate conditions is retarded; flowing said gas mixture through said passages in said burner structure whereby the gas mixture is jetted therefrom and caused to mix with air surrounding said burner; igniting the resulting gas mixture; and confining said ignited gas mixture within a vertical stack configured to allow the admission of additional air around said burner structure and to discharge combustion products into the atmosphere above said stack.

Keller, M.R.; Noble, R.K.; Pressnall, D.W.

1990-02-13

49

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

NASA Astrophysics Data System (ADS)

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.

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

2010-12-01

50

Annatto Polymeric Microparticles: Natural Product Encapsulation by the Emulsion-Solvent Evaporation Method  

ERIC Educational Resources Information Center

In this experiment, the extract from annatto seeds was encapsulated in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) particles by the emulsion-solvent evaporation method. The particles were washed and centrifuged to remove excess stabilizer and then freeze-dried. The main compound of annatto seeds, bixin, has antioxidant properties as well…

Teixeira, Zaine; Duran, Nelson; Guterres, Silvia S.

2008-01-01

51

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

52

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

Microsoft Academic Search

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., ?0.1mLfuel\\/Lgas, ?1×109droplets\\/Lgas for stoichiometric fuel loading at ambient conditions) can result in droplet–droplet interactions which lead to significant gas-phase fuel saturation and evaporative cooling

S. S. Goldsborough; M. V. Johnson; G. S. Zhu; S. K. Aggarwal

2011-01-01

53

Estimation of evaporation from open water - A review of selected studies, summary of U.S. Army Corps of Engineers data collection and methods, and evaluation of two methods for estimation of evaporation from five reservoirs in Texas  

USGS Publications Warehouse

Organizations responsible for the management of water resources, such as the U.S. Army Corps of Engineers (USACE), are tasked with estimation of evaporation for water-budgeting and planning purposes. The USACE has historically used Class A pan evaporation data (pan data) to estimate evaporation from reservoirs but many USACE Districts have been experimenting with other techniques for an alternative to collecting pan data. The energy-budget method generally is considered the preferred method for accurate estimation of open-water evaporation from lakes and reservoirs. Complex equations to estimate evaporation, such as the Penman, DeBruin-Keijman, and Priestley-Taylor, perform well when compared with energy-budget method estimates when all of the important energy terms are included in the equations and ideal data are collected. However, sometimes nonideal data are collected and energy terms, such as the change in the amount of stored energy and advected energy, are not included in the equations. When this is done, the corresponding errors in evaporation estimates are not quantifiable. Much simpler methods, such as the Hamon method and a method developed by the U.S. Weather Bureau (USWB) (renamed the National Weather Service in 1970), have been shown to provide reasonable estimates of evaporation when compared to energy-budget method estimates. Data requirements for the Hamon and USWB methods are minimal and sometimes perform well with remotely collected data. The Hamon method requires average daily air temperature, and the USWB method requires daily averages of air temperature, relative humidity, wind speed, and solar radiation. Estimates of annual lake evaporation from pan data are frequently within 20 percent of energy-budget method estimates. Results of evaporation estimates from the Hamon method and the USWB method were compared against historical pan data at five selected reservoirs in Texas (Benbrook Lake, Canyon Lake, Granger Lake, Hords Creek Lake, and Sam Rayburn Lake) to evaluate their performance and to develop coefficients to minimize bias for the purpose of estimating reservoir evaporation with accuracies similar to estimates of evaporation obtained from pan data. The modified Hamon method estimates of reservoir evaporation were similar to estimates of reservoir evaporation from pan data for daily, monthly, and annual time periods. The modified Hamon method estimates of annual reservoir evaporation were always within 20 percent of annual reservoir evaporation from pan data. Unmodified and modified USWB method estimates of annual reservoir evaporation were within 20 percent of annual reservoir evaporation from pan data for about 91 percent of the years compared. Average daily differences between modified USWB method estimates and estimates from pan data as a percentage of the average amount of daily evaporation from pan data were within 20 percent for 98 percent of the months. Without any modification to the USWB method, average daily differences as a percentage of the average amount of daily evaporation from pan data were within 20 percent for 73 percent of the months. Use of the unmodified USWB method is appealing because it means estimates of average daily reservoir evaporation can be made from air temperature, relative humidity, wind speed, and solar radiation data collected from remote weather stations without the need to develop site-specific coefficients from historical pan data. Site-specific coefficients would need to be developed for the modified version of the Hamon method.

Harwell, Glenn R.

2012-01-01

54

Are Large, Cometary-shaped Proplyds Really (Free-floating) Evaporating Gas Globules?  

NASA Astrophysics Data System (ADS)

We report the detection of strong and compact molecular line emission (in the CO J = 3-2, 4-3, 6-5, 7-6, 13CO J = 3-2, HCN, and HCO+ 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 ? 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 ?), 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.

Sahai, R.; Güsten, R.; Morris, M. R.

2012-12-01

55

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

SciTech Connect

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.

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

56

Structure and electrical properties of bismuth thin films prepared by flash evaporation method  

Microsoft Academic Search

Polycrystalline Bi thin films with thickness in the range 40–160 nm have been successfully deposited on glass substrates at 453 K by flash evaporation method for the first time. XRD and FE-SEM were performed to characterize their structure and surface morphology respectively. Electrical resistivity measurement was carried out in the temperature range 300–350 K. Hall coefficient, electron concentration and mobility were measured at

Xingkai Duan; Junyou Yang; Wen Zhu; Xi'an Fan; Chengjing Xiao

2007-01-01

57

Evaporative Thinning: A Facile Synthesis Method for High Quality Ultrathin Layers of 2D Crystals.  

PubMed

The palette of two-dimensional materials has expanded beyond graphene in recent years to include the chalcogenides among other systems. However, there is a considerable paucity of methods for controlled synthesis of mono- and/or few-layer two-dimensional materials with desirable quality, reproducibility, and generality. Here we show a facile top-down synthesis approach for ultrathin layers of 2D materials down to monolayer. Our method is based on controlled evaporative thinning of initially large sheets, as deposited by vapor mass-transport. Rather than optimizing conditions for monolayer deposition, our approach makes use of selective evaporation of thick sheets to control the eventual thickness, down to a monolayer, a process which appears to be self-stopping. As a result, 2D sheets with high yield, high reproducibility, and excellent quality can be generated with large (>10 ?m) and thin (?1-2 nm) dimensions. Evaporative thinning promises to greatly reduce the difficulty involved in isolating large, mono- and few-layers of 2D materials for subsequent studies. PMID:25233478

Huang, Yi-Kai; Cain, Jeffrey D; Peng, Lintao; Hao, Shiqiang; Chasapis, Thomas; Kanatzidis, Mercouri G; Wolverton, Christopher; Grayson, Matthew; Dravid, Vinayak P

2014-10-28

58

Method of dehydrating natural gas  

SciTech Connect

A method for dehydration of natural gas is provided wherein well head gas is supplied to a three-phase inlet separator, the vapor mixture of natural gas and water removed from that inlet separator means is supplied to a turboexpander, and the resulting refrigerated mixture of natural gas and condensed water vapor is supplied to a multi-phase outlet separator. The turboexpander may have integral means for subsequent compression of the refrigerated mixture and may be coupled through reduction gears to a means for generating electricity. A portion of the refrigerated mixture may be connected to a heat exchanger for cooling the well head natural gas prior to entry into the inlet separator. The flow of refrigerated mixture to this heat exchanger may be controlled by a temperature sensitive valve downstream of the heat exchanger. Methanol may be injected into the vapor mixture prior to entry into the turboexpander. The flow of methanol into the vapor mixture may be controlled by a valve sensitive to the flow rate of the vapor mixture and the water vapor content of the refrigerated mixture. Natural gas vapor from the outlet separator may be recirculated through the turboexpander if the output water vapor content of the natural gas vapor stream is too high.

Wells, R. E.

1985-01-01

59

Development of a novel method based on liquid chromatography–evaporative light scattering detection for the direct determination of streptomycin and dihydrostreptomycin in raw materials, pharmaceutical formulations, culture media and plasma  

Microsoft Academic Search

A novel method for the non-derivatization liquid chromatographic determination of streptomycin (STR) and dihydrostreptomycin (DHSTR) was developed and validated based on evaporative light scattering detection (ELSD). Utilizing a ThermoHypersil BetaBasic C18 analytical column, evaporation temperature of 50°C and pressure of nebulizing gas (nitrogen) of 3.5bar, the optimized mobile phase was 1.25mLL?1 TFA aqueous solution, in an isocratic mode at a

Artemis K. Sarri; Nikolaos C. Megoulas; Michael A. Koupparis

2006-01-01

60

Electron beam evaporated carbon doping of InGaAs layers grown by gas source molecular beam epitaxy  

SciTech Connect

The authors have studied carbon doping of GaInAs grown by gas-source molecular beam epitaxy. Graphite was used as a source material for carbon evaporation. GaInAs was studied due to its importance as a base layer in InP-based heterojunction bipolar transistors. They show that useful p-type acceptor concentrations can be achieved by evaporation from graphite source for GaInAs grown by gas-source molecular beam epitaxy. Secondary ion mass spectroscopy and Van der Pauw Hall measurements were used to characterize the carbon and net acceptor concentrations of their GaInAs layers. The effect of rapid thermal annealing on acceptor concentrations and Hall mobilities was also studied.

Salokatve, A.; Toivonen, M.; Asonen, H.; Pessa, M. [Tampere Univ. of Technology (Finland). Dept. of Physics; Likonen, J. [Technical Research Center of Finland, VTT (Finland)

1996-12-31

61

Quantifying Evaporation and Evaluating Runoff Estimation Methods in a Permeable Pavement System - abstract  

EPA Science Inventory

Studies on quantifying evaporation in permeable pavement systems are limited to few laboratory studies that used a scale to weigh evaporative losses and a field application with a tunnel-evaporation gauge. A primary objective of this research was to quantify evaporation for a la...

62

Continuous flow, evaporative-type thermal energy recovery apparatus and method for thermal energy recovery  

Microsoft Academic Search

A continuous flow, evaporative-type thermal energy recovery apparatus comprises an evaporator unit to which are supplied continuous pressurized flows of hot water and air, and in which a portion of the hot water is evaporated into the air, preferably to completely saturate the air with moisture. Connected to receive the resulting flow of pressurized, water saturated air from the evaporator

Bissell

1978-01-01

63

Evaluation of equilibrium and non-equilibrium evaporation models for many-droplet gas-liquid flow simulations  

Microsoft Academic Search

A variety of liquid droplet evaporation models, including both classical equilibrium and non-equilibrium Langmuir–Knudsen formulations, are evaluated through comparisons with experiments with particular emphasis on computationally efficient procedures for gas–liquid flow simulations. The models considered are those used in droplet laden flow calculations such as direct numerical simulations for which large numbers of individual (isolated) droplet solutions are obtained. Diameter

R. S. Miller; K. Harstad; J. Bellan

1998-01-01

64

SiO(x) nanoparticles synthesized by an evaporation and condensation process using induction melting of silicon and gas injection.  

PubMed

SiO(x) nanoparticles were synthesized using a specially designed induction melting system equipped with a segmented graphite crucible. The graphite crucible with the segmented wall was the key to enhancing the evaporation rate due to the increase of the evaporation area and convection of the silicon melt. Injection of the gas mixture of oxygen (O2) and argon (Ar) on silicon (Si) melt caused the formation of SiO(x) nanoparticles. The evaporated SiO(x) nanoparticles were then cooled and condensed in a process chamber. The effects of the O2/Ar ratio in the injection gas on the microstructures of the SiO(x) nanoparticles were then investigated. Synthesized SiO(x) nanoparticles were proven to be of a homogeneous amorphous phase with average diameters of 30-35 nm. The microstructures were independent from the O2/Ar ratio of the injected gas. However, x increased from 1.36 to 1.84 as the O2/Ar ratio increased. The purity of the synthesized nanoparticles was about 99.9%. SiO(x) nanoparticles could be applied as the active anode material in a lithium (Li) ion secondary battery. PMID:23858929

Jang, Bo Yun; Lee, Jin Seok; Kim, Joon Soo

2013-05-01

65

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

66

Full evaporation headspace gas chromatography for sensitive determination of high boiling point volatile organic compounds in low boiling matrices.  

PubMed

Determination of volatile organic components (VOC's) is often done by static headspace gas chromatography as this technique is very robust and combines easy sample preparation with good selectivity and low detection limits. This technique is used nowadays in different applications which have in common that they have a dirty matrix which would be problematic in direct injection approaches. Headspace by nature favors the most volatile compounds, avoiding the less volatile to reach the injector and column. As a consequence, determination of a high boiling solvent in a lower boiling matrix becomes challenging. Determination of VOCs like: xylenes, cumene, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMA), N-methyl-2-pyrrolidone (NMP), 1,3-dimethyl-2-imidazolidinone (DMI), benzyl alcohol (BA) and anisole in water or water soluble products are an interesting example of the arising problems. In this work, a headspace variant called full evaporation technique is worked out and validated for the mentioned solvents. Detection limits below 0.1 ?g/vial are reached with RSD values below 10%. Mean recovery values ranged from 92.5 to 110%. The optimized method was applied to determine residual DMSO in a water based cell culture and DMSO and DMA in tetracycline hydrochloride (a water soluble sample). PMID:24103808

Mana Kialengila, Didi; Wolfs, Kris; Bugalama, John; Van Schepdael, Ann; Adams, Erwin

2013-11-01

67

Preparation of polymeric microspheres by the solvent evaporation method using sucrose stearate as a droplet stabilizer.  

PubMed

Polymeric microspheres containing nicardipine hydrochloride (HCl) as a reference drug were prepared with the acrylic polymers Eudragit RS and L by the solvent evaporation method. Different concentrations of sucrose stearate as a droplet stabilizer were used. Sucrose stearate affected the diffusion rate of the solvent from the preliminary emulsion droplets to the outer phase for the formation of microspheres. Increasing concentrations of sucrose stearate in the formulations caused increasing porosity on the surface of the microspheres. However, a correlation between the concentrations of sucrose stearate and diameters of microspheres could not be assessed. From this point of view, during processing, applied stirring rate was important. PMID:9394253

Yüksel, N; Baykara, T

1997-01-01

68

Method and apparatus for fuel gas moisturization and heating  

DOEpatents

Fuel gas is saturated with water heated with a heat recovery steam generator heat source. The heat source is preferably a water heating section downstream of the lower pressure evaporator to provide better temperature matching between the hot and cold heat exchange streams in that portion of the heat recovery steam generator. The increased gas mass flow due to the addition of moisture results in increased power output from the gas and steam turbines. Fuel gas saturation is followed by superheating the fuel, preferably with bottom cycle heat sources, resulting in a larger thermal efficiency gain compared to current fuel heating methods. There is a gain in power output compared to no fuel heating, even when heating the fuel to above the LP steam temperature.

Ranasinghe, Jatila (Niskayuna, NY); Smith, Raub Warfield (Ballston Lake, NY)

2002-01-01

69

The inert gas effect on the rate of evaporation of zinc and cadmium  

NASA Astrophysics Data System (ADS)

An experimental study has been made to investigate the effect of argon and helium on the rate of evaporation of zinc and cadmium under one atmosphere pressure at temperatures ranging from 500 to 850°C. The experimental results were compared with the maximum rates calculated using the effusion formula as well as with values obtained using two different types of equations based on kinetic theory, diffusion theory, and empirical data. Equations have been derived for expressing the rate of evaporation of zinc and cadmium in both argon and helium as functions of temperature of the liquid zinc and cadmium. It was found that the rates of evaporation of zinc and cadmium were higher in helium than in argon, with the difference increasing with increasing temperature. It was also found that the experimental results obtained in argon agree with the calculated values better than those obtained in helium.

Wu, P. C. S.; O'Keefe, T. J.; Kisslinger, F.

1980-12-01

70

Development, characterization and solubility study of solid dispersions of azithromycin dihydrate by solvent evaporation method.  

PubMed

Azithromycin Dihydrate (Poorly water soluble drug), when prepared as solid dispersion showed improved solubility and dissolution. So the main purpose of this investigation was to increase the solubility and dissolution rate of Azithromycin Dihydrate by the preparation of its solid dispersion with urea using solvent evaporation method. Physical mixtures and solid dispersions of Azithromycin Dihydrate were prepared by using urea as water-soluble carrier in various proportions (1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7 by weight), by employing solvent evaporation method. The drug release profile was studied and it was found that the dissolution rate and the dissolution parameters of the drug from the physical mixture as well as solid dispersion were higher than those of the intact drug. FT- IR spectra revealed no chemical incompatibility between drug and urea. Drug-polymer interactions were investigated using differential scanning calorimetry (DSC) and Powder X-Ray Diffraction (PXRD). PMID:22247849

Arora, S C; Sharma, P K; Irchhaiya, Raghuveer; Khatkar, Anurag; Singh, Neeraj; Gagoria, Jagbir

2010-04-01

71

Development, characterization and solubility study of solid dispersions of Cefuroxime Axetil by the solvent evaporation method.  

PubMed

Cefuroxime Axetil (Poorly water soluble drug), when prepared as solid dispersion showed improved solubility and dissolution. Therefore, the main purpose of this investigation was to increase the solubility and dissolution rate of Cefuroxime Axetil by the preparation of its solid dispersion with urea, using the solvent evaporation method. Physical mixtures and solid dispersions of Cefuroxime Axetil were prepared by using urea as a water-soluble carrier in various proportions (1:1, 1:2, 1:3, 1:4, 1:5, 1:6, and 1:7 by weight), by employing the solvent evaporation method. The drug release profile was studied and it was found that the dissolution rate and the dissolution parameters of the drug from the physical mixture as well as solid dispersion were higher than those of the intact drug. The Fourier Transform Infrared (FTIR) spectra revealed no chemical incompatibility between the drug and urea. Drug-polymer interactions were investigated using differential scanning calorimetry (DSC) and Powder X-Ray Diffraction (PXRD). PMID:22247865

Arora, S C; Sharma, P K; Irchhaiya, Raghuveer; Khatkar, Anurag; Singh, Neeraj; Gagoria, Jagbir

2010-07-01

72

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

PubMed

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

Alshamsan, Aws

2014-07-01

73

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

PubMed Central

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

Alshamsan, Aws

2013-01-01

74

Uranium and Calcium Isotope Ratio Measurements using the Modified Total Evaporation Method in TIMS  

NASA Astrophysics Data System (ADS)

A new version of the "modified total evaporation" (MTE) method for isotopic analysis by multi-collector thermal ionization mass spectrometry (TIMS), with high analytical performance and designed in a more user-friendly and routinely applicable way, is described in detail. It is mainly being used for nuclear safeguards measurements of U and Pu and nuclear metrology, but can readily be applied to other scientific tasks in geochemistry, e.g. for Sr, Nd and Ca, as well. The development of the MTE method was organized in collaboration of several "key nuclear mass spectrometry laboratories", namely the New Brunswick Laboratory (NBL), the Institute for Transuranium Elements (ITU), the Safeguards Analytical Laboratory (now Safeguards Analytical Services, SGAS) of the International Atomic Energy Agency (IAEA) and the Institute for Reference Materials and Measurements (IRMM), with IRMM taking the leading role. The manufacturer of the TRITON TIMS instrument, Thermo Fisher Scientific, integrated this method into the software of the instrument. The development has now reached its goal to become a user-friendly and routinely useable method for uranium isotope ratio measurements with high precision and accuracy. Due to the use of the “total evaporation” (TE) method the measurement of the "major" uranium isotope ratio 235U/238U is routinely being performed with a precision of 0.01% to 0.02%. The use of a (certified) reference material measured under comparable conditions is emphasized to achieve an accuracy at a level of 0.02% - depending on the stated uncertainty of the certified value of the reference material. In contrast to the total evaporation method (TE), in the MTE method the total evaporation sequence is interrupted on a regular basis to allow for correction for background from peak tailing, internal calibration of a secondary electron multiplier (SEM) detector versus the Faraday cups, and ion source re-focusing. Therefore, the most significant improvement using the MTE method is in the analytical performance achieved for the "minor" ratios 234U/238U and 236U/238U. The MTE method is now routinely used at all collaborating laboratories and possibly more in the future. Additional applications for the MTE method, e.g. to take advantage of the good external precision in combination with the possibilities of internal background and detector calibrations or mass jumps between different cup configurations, are presented as well. One interesting application concerns new absolute isotope ratio measurements for Ca with an unprecedented level of accuracy. This is important because up to now most reported Ca isotope data are only calculated as relative deviations from a standard like NIST-SRM 915. Using the MTE method measurements on new gravimetrically prepared Ca isotope mixtures were performed. A significantly improved level of accuracy at the level of about 0.02% for both the 42Ca/40Ca and 44Ca/40Ca ratios was obtained.

Richter, S.; Kuehn, H.; Berglund, M.; Hennessy, C.

2010-12-01

75

The inert gas effect on the rate of evaporation of zinc and cadmium  

Microsoft Academic Search

An experimental study has been made to investigate the effect of argon and helium on the rate of evaporation of zinc and cadmium under one atmosphere pressure at temperatures ranging from 500 to 850°C. The experimental results were compared with the maximum rates calculated using the effusion formula as well as with values obtained using two different types of equations

P. C. S. Wu; T. J. O'Keefe; F. Kisslinger

1980-01-01

76

TiO2 Based Nanocrystalline Thin Film Gas Sensors Prepared by Ion-assisted Electron beam Evaporation  

Microsoft Academic Search

In this work, we develop TiO2 based nanocrystalline thin films prepared by ion-assisted e-beam evaporation process. N-type and p-type TiO2 gas-sensing layers have been deposited by doping with various metal oxide materials including WO3, MoO3, and NiOx. Structural and morphological characterization by means of AFM, SEM, and XRD reveal the thin film is nanocrystalline structure with fine grain of 10-30

A. Wisitsoraat; E. Comini; G. Sberveglieri; W. Wlodarski; A. Tuantranont

2007-01-01

77

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

SciTech Connect

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)

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

78

The inert gas effect on the rate of evaporation of zinc and cadmium  

Microsoft Academic Search

An experimental study has been made to investigate the effect of argon and helium on the rate of evaporation of zinc and cadmium\\u000a under one atmosphere pressure at temperatures ranging from 500 to 850°C. The experimental results were compared with the maximum\\u000a rates calculated using the effusion formula as well as with values obtained using two different types of equations

P. C. S. Wu; T. J. O’keefe; F. Kisslinger

1980-01-01

79

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

PubMed

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

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

2013-12-01

80

Catalyst free growth of ZnO nanorods by thermal evaporation method  

SciTech Connect

In this work, we report catalyst free growth of ZnO nanorods on n-Si substrate by a low cost thermal evaporation method. The surface morphology, chemical composition and crystalline structure of ZnO nanorods have been determined by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) spectroscopy respectively. It is found that, the as -deposited ZnO seed layer reduces lattice mismatching between ZnO and Si from 40.3 to 0.28%, therefore enhances the subsequent growth and crystalline quality of ZnO nanorods on Si substrate. The present methodology is simple, cost effective and highly applicable for synthesis of ZnO nanorods for optoelectronics applications.

Somvanshi, Divya; Jit, S. [Centre for Research in Microelectronics (CRME), Department of Electronics Engineering Indian Institute of Technology (Banaras Hindu University), Varanasi Uttar Pradesh-221005 (India)

2013-06-03

81

Preparation of Eudragit E100 microspheres by modified solvent evaporation method.  

PubMed

The objective of this investigation was to develop the hollow microspheres as a new dosage form of floating drug delivery system with prolonged stomach retention time. Hollow microspheres containing ranitidine hydrochloride were prepared by solvent evaporation method using Eudragit RLPO dissolved in a mixture of dichloromethane and ethanol. The maximum yield and drug loading amount of hollow microspheres were 88.45% and 80 +/- 4.0%, respectively. The in vitro release profiles showed that the drug release rate decreased with increasing viscosity of Eudragit RLPO, while diameter of hollow microspheres increased with the increase of drug polymer weight ratio. Hollow microspheres could prolong drug release time (approximately 24 h) and float over stimulate gastric fluid for more than 12 h. These results demonstrated that ranitidine HCl hollow microspheres were capable of sustained delivery of the drug for longer period with increased bioavailability. PMID:22125964

Singh, Vandana; Chaudhary, Amrendra Kumar

2011-01-01

82

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

USGS Publications Warehouse

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

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

1993-01-01

83

Group evaporation  

NASA Technical Reports Server (NTRS)

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.

Shen, Hayley H.

1991-01-01

84

Flue gas desulfurization apparatus and method  

Microsoft Academic Search

A method of desulfurizing boiler flue gas by intimate contact thereof with dry particles of a reactant or absorbent, such as hydrated lime, preferably with recirculation of the flue gas and entrained reactant or absorbent particles. An apparatus suitable for carrying out the method comprises an upstanding conduit defining a vertical gas flow path in communication with a source of

F. S. Flick; G. T. Hollett

1981-01-01

85

A flux-limited treatment for the conductive evaporation of spherical interstellar gas clouds  

NASA Technical Reports Server (NTRS)

In this work, we present and analyze a new analytic solution for the saturated (flux-limited) thermal evaporation of a spherical cloud. This work is distinguished from earlier analytic studies by allowing the thermal conductivity to change continuously from a diffusive to a saturated form, in a manner usually employed only in numerical calculations. This closed form solution will be of interest as a computational benchmark. Using our calculated temperature profiles and mass-loss rates, we model the thermal evaporation of such a cloud under typical interstellar medium (ISM) conditions, with some restrictions. We examine the ionization structure of the cloud-ISM interface and evaluate column densities of carbon, nitrogen, oxygen, neon, and silicon ions toward the cloud. In accord with other investigations, we find that ionization equilibrium is far from satisfied under the assumed conditions. Since the inclusion of saturation effects in the heat flux narrows the thermal interface relative to its classical structure, we also find that saturation effects tend to lower predicted column densities.

Dalton, William W.; Balbus, Steven A.

1993-01-01

86

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

PubMed Central

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.

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

2014-01-01

87

Integrated flue gas processing method  

Microsoft Academic Search

A system and process for flue gas processing to remove both gaseous contaminants such as sulfur dioxide and particulate matter such as flyash integrates spray scrubbing apparatus and wet electrostatic precipitation apparatus and provides for the advantageous extraction and utilization of heat present in the flue gas which is being processed. The integrated system and process utilizes a spray scrubbing

E. Bakke; H. P. Willett

1982-01-01

88

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

PubMed

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

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

2011-10-01

89

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

PubMed Central

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

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

90

Could CoRoT-7b and Kepler-10b be remnants of evaporated gas or ice giants? M. Leitzinger a,, P. Odert a  

E-print Network

Could CoRoT-7b and Kepler-10b be remnants of evaporated gas or ice giants? M. Leitzinger a,Ã?, P Received in revised form 19 April 2011 Accepted 10 June 2011 Available online 21 June 2011 Keywords: CoRoT calculations over evolutionary time scales for the investigation if the smallest transiting rocky exoplanets CoRoT

Micela, Giusi

91

Development of a specimen heating holder with an evaporator and gas injector and its application for catalyst.  

PubMed

A specimen heating holder equipped with a gas injector and an evaporator has been developed for use with conventional transmission electron microscopes (TEMs). The developed specimen holder allows both synthesis of metal oxide support and deposition of catalyst nano-particles in situ. Since the holder is designed to be used in small gapped high-resolution objective lens pole-piece, all the procedure from the synthesis of support material to the deposition of catalyst as well as the behavior of the catalyst nano-particles on the support can be observed at near atomic resolution. The developed specimen holder was applied to the study of AuPd catalyst. First, air was injected onto heated aluminum particles via a gas injector to synthesize Al(2)O(3) support. Then, nano-particles of AuPd were deposited on the Al(2)O(3) support. After the deposition, the synthesized Al(2)O(3) support was heated and air was injected again to observe behaviors of the deposited AuPd nano-particles at elevated temperatures in the aerial environment. Behaviors of the AuPd nano-particles such as coalescence, segmentation and diffusion to the Al(2)O(3) support were dynamically observed at atomic level high resolution. PMID:17135215

Takeo, Kamino; Toshie, Yaguchi; Mitsuru, Konno; Akira, Watabe; Yasuhira, Nagakubo

2006-10-01

92

The detection of evaporating hazardous material released from moving sources using a gas sensor network  

Microsoft Academic Search

Sensor information resulting from distributed locations and\\/or a multitude of instruments and heterogeneous sensors can increase the reliability of safety and security applications.A gas-sensing platform was developed, communicating via a wireless sensor network based on IEEE 802.15.4 and\\/or Ethernet. Data from this network are aggregated via a central server feeding its information via TCP\\/IP into subsequent data fusion software. The

C. Becher; P. Kaul; J. Mitrovics; J. Warmer

2010-01-01

93

Cellular uptake of ?-carotene from protein stabilized solid lipid nanoparticles prepared by homogenization-evaporation method.  

PubMed

With a homogenization-evaporation method, ?-carotene (BC) loaded nanoparticles 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 cellular uptake by Caco-2 cells. The particle diameters of the BC loaded nanoparticles with 0.75% SC or 1.0% WPI emulsifiers were 75 and 90 nm, respectively. Mean particle diameters of three BC loaded nanoparticle nanoemulsions increased less than 10% at 4 °C while they increased more at 25 °C (10-76%) during 30 days of storage. The oxidative stability of BC loaded nanoparticles encapsulated by proteins decreased in the following order: SC > WPI > SPI. The retention rates of BC in nanoparticles were 63.5%, 60.5%, and 41.8% for SC, WPI, and SPI, respectively, after 30 days of storage at 25 °C. The BC's chemical stability was improved by increasing the concentration of protein. Both the rate of particle growth and the total BC loss at 25 °C were larger than at 4 °C. The color of BC loaded nanoparticles decreased with increasing storage in the dark without oxygen, similar to the decrease in BC content of nanoparticles at 4 and 25 °C. Almost no cytotoxicity due to BC loaded nanoparticles cellular uptake was observed, especially when diluted 10 times or more. The uptake of BC was significantly improved through nanoparticle delivery systems by 2.6-, 3.4-, and 1.7-fold increase, respectively, for SC, WPI, and SPI, as compared to the free BC. The results of this study indicate that protein stabilized, BC loaded nanoparticles can improve stability and uptake of BC. PMID:24422504

Yi, Jiang; Lam, Tina I; Yokoyama, Wallace; Cheng, Luisa W; Zhong, Fang

2014-02-01

94

FIELD DEPLOYMENT EVALUATION OF THE FREEZE-THAW/EVAPORATION (FTE) PROCESS TO TREAT OIL AND GAS PRODUCED WATERS. Task 45. Final topical report  

SciTech Connect

TASK 45 FIELD DEPLOYMENT EVALUATION OF THE FREEZE-THAW/ EVAPORATION (FTE ) PROCESS TO TREAT OIL AND GAS PRODUCED WATERS coupling evaporation with freezing. This offers operators a year- round method for treating produced water. Treating water with the FTE process reduces the volume of water to be disposed of as well as purifying the water to a level acceptable for watering livestock and agricultural lands. This process is currently used at two evaporation facilities, one in the San Juan Basin in New Mexico and one in the Green River Basin in Wyoming. the freezing point below that of pure water. When such a solution is cooled below 32EF, relatively pure ice crystals form, along with an unfrozen brine solution that contains elevated concentrations of salts. Because of the brine's high concentration of these constituents, its density is greater than that of the ice, and the purified ice and brine are easily separated. Coupling the natural processes of freezing and evaporation makes the FTE process a more cost- effective and efficient method for the treatment and disposal of produced water and allows for year-round operation of an FTE facility. drops below 32 F, produced water is automatically pumped from a holding pond and sprayed onto a freezing pad. The freezing pad consists of an elevated framework of piping with regularly placed, upright, extendable spray heads similar to those used to irrigate lawns. As the spray freezes, an ice pile forms over the elevated framework of pipes, and the brine, with an elevated constituent concentration, drains from the ice pile. The high-salinity brine, identified by its high electrical conductivity, is separated using automatic valves and pumped to a pond where it can subsequently be disposed of by conventional methods. As the ice pile increases in height, the sprayers are extended. When the ice on the freezing pad melts, the relatively pure water is pumped from the freezing pad and discharged or stored for later use . No new wastes are generated by the FTE process. and the U. S. Department of Energy has been conducted since 1992 to develop a commercial FTE purification process for produced waters. Numeric process and economic modeling, as well as the laboratory-scale process simulation that confirmed the technical and economic feasibility of the process, was performed by B. C. Technologies, Ltd., and the University of North Dakota Energy & Environmental Research Center (EERC) from 1992 to 1995. They then conducted a field evaluation from 1995 to 1997 in New Mexico's San Juan Basin at a conventional evaporation facility operated by Amoco Production Company. The results of this evaluation confirmed that the FTE process has significant commercial economic potential. A new facility was designed in 1998, and its construction is expected to begin in 1999.

Ames A. Grisanti; James A. Sorensen

1999-05-01

95

Properties of vacuum evaporated vapour chopped polyaniline thin film: effect of synthesis method  

Microsoft Academic Search

The paper reports optical properties and adhesion of polyaniline thin film prepared by vacuum evaporated polyaniline powder synthesized in acidic and nonacidic medium respectively. The effect of vapour chopping on its optical and adhesion properties is also studied. Maximum transmittance 85% and 90% was obtained for polyaniline thin film deposited from polyaniline powder synthesized from nonacidic and acidic medium respectively.

J. B. Yadav; S. Jhadav; R. K. Puri; V. Puri

2008-01-01

96

A dynamic negative-ion mixing method using high-current heavy ions and electron beam evaporation  

Microsoft Academic Search

A new filmmaking technique with high-current negative ions and electron beam evaporation has been developed to fabricate optical insulating films, applying both ion-induced dynamic processes and simultaneous formation of insulating substrates. The dynamic negative-ion mixing (DNIM) method, with negative ions at high dose rates, alleviates surface charging on insulators and attains mass introduction of metal atoms. Negative Cu ions of

N. Kishimoto; J. P. Zhao; N. Okubo; Y. Takeda; V. T. Gritsyna

2000-01-01

97

Instrumentation for measuring lake and reservoir evaporation by the energy-budget and mass-transfer methods  

USGS Publications Warehouse

Instrumentation currently used by the U.S. Geological Survey in studies of lake and reservoir evaporation is described in this paper. This instrumentation is used for the measurement of solar and terrestrial energy necessary to apply the mass-transfer or energy budget methods. The energy budget requires a quantative determination of all form of energy entering or leaving the lake as well as determination of the change in storage of energy within the lake. (USGS)

Sturrock, A. M., Jr.

1985-01-01

98

Evaporation Investigation  

NSDL National Science Digital Library

This is a hands-on lab activity about evaporation. Learners will conduct experiments to observe the process of evaporation. They will then describe the process of evaporation, and the general water cycle, through discussion and pictures. Background information, common preconceptions, a glossary and more is included. This activity is part of the Aquarius Hands-on Laboratory Activities.

99

Exploring Evaporation  

NSDL National Science Digital Library

Students learn what evaporation is and how various factors--time, heat, surface area, and wind--affect it. They also discover that water does not always evaporate at the same rate and saltwater leaves something behind when it evaporates. Finally, students a

Eichinger, John

2009-05-15

100

Laboratory simulation of processes of evaporation, condensation, and sputtering taking place on the surface of the moon  

NASA Technical Reports Server (NTRS)

Study of evaporation, condensation and sputtering on the moon can provide information on the same processes on other planets, and reveal details of the formation of the lunar regolith. Simulation methods include vacuum evaporation, laser evaporation, and bubbling gas through melts.

Nusinov, M. D.; Kochnev, V. A.; Chernyak, Y. B.; Kuznetsov, A. V.; Kosolapov, A. I.; Yakovlev, O. I.

1974-01-01

101

Electrical and optical properties of ZnO: Al films prepared by an evaporation method  

Microsoft Academic Search

This paper describes the preparation of aluminium-doped zinc oxide films by thermal evaporation of zinc acetate (Zn(CH3COO)2 · 2H2O) and aluminium chloride (AlCl3) onto a heated glass substrate. The structural, optical and electrical properties of the deposited films were investigated. Highly transparent films with a conductivity as high as 2.3 × 102 ??1cm?1 can be produced by controlling the deposition

Jin Ma; Feng Ji; Hong-lei Ma; Shu-ying Li

1996-01-01

102

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

PubMed Central

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

Musolino, Nicholas; Trout, Bernhardt L.

2013-01-01

103

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

NASA Astrophysics Data System (ADS)

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.

Telgozhayeva, D. S.

2014-08-01

104

Method for dismantling a natural gas holder  

SciTech Connect

This patent describes a method of dismantling a natural gas holder. The holder has vertical support columns disposed around the periphery of the holder to which the enclosure shell of the holder is attached.

Settlemier, B.R.; Bone, S.R.; Tolivaisa, J.; Nugent, J.E.

1990-10-30

105

Method and apparatus for shale gas recovery  

SciTech Connect

This patent describes a method for the in situ recovery of natural gas from an undisturbed shale bed formation in a condition ready for transmission through a gas pipeline to end users and substantially without the formation of liquid products. It comprises: forming a heater assembly having an elongated substantially cylindrical outer housing; providing the elongated heater assembly with an interior containing a fuel gas burner there within joined to an upwardly extending fuel gas supply line and including in the interior an upwardly extending product gas line disposed adjacent an upwardly extending combustion air line; drilling a borehole into a subterranean shale bed formation; and lowering the heater assembly into the borehole to a position surrounded by the shale bed formation with the borehole having been drilled to define a diameter relative the heater assembly housing insuring a close fit therebetween while providing a gas space therebetween.

Nielson, D.H.

1990-05-29

106

EVAPORATION OF CAI LIQUIDS INTO SOLAR GAS. A. V. , L. Grossman1,2  

E-print Network

in equilibrium with the droplet surface were calculated as a function of temperature from 2000 to 1500K (the of Chicago, Chicago, IL 60637. (avf@uchicago.edu) In [1], a method for calculating the vapor pressure of a CaO- MgO-Al2O3-SiO2 (CMAS) liquid droplet in pure H2 was used to calculate the evolution of the bulk

Grossman, Lawrence

107

Intercomparison of stack gas mercury measurement methods  

Microsoft Academic Search

The Electric Power Research Institute (EPRI) and the United States Environmental Protection Agency (EPA) have carried out joint tests for validation of EPA (Draft) Method 29 (“multi-metals method”) for measurement of mercury (Hg) and other selected metals in the stack gas of a coal-fired electric utility. The tests were performed according to the “analyte spiking” procedure of EPA Method 301

Babu R. Nott

1995-01-01

108

Canadian Shield brine from the Con Mine, Yellowknife, NT, Canada: Noble gas evidence for an evaporated Palaeozoic seawater origin mixed with glacial meltwater and Holocene recharge  

Microsoft Academic Search

Dissolved noble gas concentrations were measured in high salinity (270g\\/L) Ca(Na)-Cl groundwaters from the Con Mine, Yellowknife, Canada in an effort to discriminate between two possible origins, as either a brine generated by evaporative enrichment in a Paleozoic inland sea, or marine water concentrated by freezing during glacial times. Major ion and isotope geochemistry indicate that brines from the deepest

Shane Greene; Nick Battye; Ian Clark; Tom Kotzer; Dennis Bottomley

2008-01-01

109

Witnessing Evaporation  

NSDL National Science Digital Library

The engineers at Splash Engineering (the students) have been commissioned by Thirsty County to conduct a study of evaporation and transpiration in their region. During one week, students observe and measure (by weight) the ongoing evaporation of water in pans set up with different variables, and then assess what factors may affect evaporation. Variables include adding to the water an amount of soil and an amount of soil with growing plants.

Integrated Teaching And Learning Program

110

Consistent simulation of droplet evaporation based on the phase-field multiphase lattice Boltzmann method  

NASA Astrophysics Data System (ADS)

In the present article, we extend and generalize our previous article [H. Safari, M. H. Rahimian, and M. Krafczyk, Phys. Rev. E 88, 013304 (2013), 10.1103/PhysRevE.88.013304] to include the gradient of the vapor concentration at the liquid-vapor interface as the driving force for vaporization allowing the evaporation from the phase interface to work for arbitrary temperatures. The lattice Boltzmann phase-field multiphase modeling approach with a suitable source term, accounting for the effect of the phase change on the velocity field, is used to solve the two-phase flow field. The modified convective Cahn-Hilliard equation is employed to reconstruct the dynamics of the interface topology. The coupling between the vapor concentration and temperature field at the interface is modeled by the well-known Clausius-Clapeyron correlation. Numerous validation tests including one-dimensional and two-dimensional cases are carried out to demonstrate the consistency of the presented model. Results show that the model is able to predict the flow features around and inside an evaporating droplet quantitatively in quiescent as well as convective environments.

Safari, Hesameddin; Rahimian, Mohammad Hassan; Krafczyk, Manfred

2014-09-01

111

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

USGS Publications Warehouse

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.

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

2005-01-01

112

Modelling non-equilibrium secondary organic aerosol formation and evaporation with the aerosol dynamics, gas- and particle-phase chemistry kinetic multi-layer model ADCHAM  

NASA Astrophysics Data System (ADS)

We have developed the novel Aerosol Dynamics, gas- and particle-phase chemistry model for laboratory CHAMber studies (ADCHAM). The model combines the detailed gas phase Master Chemical Mechanism version 3.2, an aerosol dynamics and particle phase chemistry module (which considers acid catalysed oligomerization, heterogeneous oxidation reactions in the particle phase and non-ideal interactions between organic compounds, water and inorganic ions) and a kinetic multilayer module for diffusion limited transport of compounds between the gas phase, particle surface and particle bulk phase. In this article we describe and use ADCHAM to study: (1) the mass transfer limited uptake of ammonia (NH3) and formation of organic salts between ammonium (NH4+) and carboxylic acids (RCOOH), (2) the slow and almost particle size independent evaporation of ?-pinene secondary organic aerosol (SOA) particles, and (3) the influence of chamber wall effects on the observed SOA formation in smog chambers. ADCHAM is able to capture the observed ?-pinene SOA mass increase in the presence of NH3(g). Organic salts of ammonium and carboxylic acids predominantly form during the early stage of SOA formation. These salts contribute substantially to the initial growth of the homogeneously nucleated particles. The model simulations of evaporating ?-pinene SOA particles support the recent experimental findings that these particles have a semi-solid tar like amorphous phase state. ADCHAM is able to reproduce the main features of the observed slow evaporation rates if low-volatility and viscous oligomerized SOA material accumulates in the particle surface layer upon evaporation. The evaporation rate is mainly governed by the reversible decomposition of oligomers back to monomers. Finally, we demonstrate that the mass transfer limited uptake of condensable organic compounds onto wall deposited particles or directly onto the Teflon chamber walls of smog chambers can have profound influence on the observed SOA formation. During the early stage of the SOA formation the wall deposited particles and walls themselves serve as a SOA sink from the air to the walls. However, at the end of smog chamber experiments the semi-volatile SOA material may start to evaporate from the chamber walls. With these three model applications, we demonstrate that several poorly quantified processes, i.e. mass transport limitations within the particle phase, oligomerization, heterogeneous oxidation, organic salt formation, and chamber wall effects can have substantial influence on the SOA formation, lifetime, chemical and physical particle properties, and their evolution. In order to constrain the uncertainties related to these processes, future experiments are needed where as many of the influential variables as possible are varied. ADCHAM can be a valuable model tool in the design and analysis of such experiments.

Roldin, P.; Eriksson, A. C.; Nordin, E. Z.; Hermansson, E.; Mogensen, D.; Rusanen, A.; Boy, M.; Swietlicki, E.; Svenningsson, B.; Zelenyuk, A.; Pagels, J.

2014-01-01

113

Performance of a showcase refrigeration system with multi-evaporator during on–off cycling and hot-gas bypass defrost  

Microsoft Academic Search

During the defrosting process, the temperature in the cabinet of a showcase becomes higher than the set point. This phenomenon is undesirable for foods or products stored. It is essential to develop an efficient defrosting method to prevent large temperature fluctuations. In the present study, the performance of the showcase refrigeration system with three evaporators was measured during on–off cycling

Honghyun Cho; Yongchan Kim; Inkyu Jang

2005-01-01

114

Method for improved gas-solids separation  

DOEpatents

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 when it is discharged out of the top of the apparatus. Separated particulates are removed from the bottom of the vessel.

Kusik, Charles L. (Lincoln, MA); He, Bo X. (Newton, MA)

1990-01-01

115

Method for improved gas-solids separation  

DOEpatents

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.

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

1990-11-13

116

Nuclear Instruments and Methods in Physics Research A 551 (2005) 330338 A high-efficiency compact setup to study evaporation  

E-print Network

setup to study evaporation residues formed in reactions induced by low-intensity radioactive ion beams Available online 22 July 2005 Abstract A setup for measuring cross-sections of evaporation residues produced on lighter-mass targets. The system as presented here has been optimized to study evaporation residues from

117

Hybrid Evaporative - Condenser Cooling Tower  

Microsoft Academic Search

The need to save energy in power producing and power consuming systems and the fact that evaporative cooling is the most efficient method for heat rejection led to the design and testing of a model of a special cooling tower, fn this hybrid system an evaporative condenser is being built into the cooling tower and the advantages of evaporative cooling

Uriyel Fisher; Wolfgang Leidenfrost; Jiashang Li

1981-01-01

118

A simple method to make an electrical connection between ZnO microwire and substrate through nanoscale metal evaporation  

NASA Astrophysics Data System (ADS)

We developed a simple method to make an electrical connection with nanoscale electrodes on microscale wire using suspended Poly(methyl methacrylate) (PMMA) strings. Less than 90 nm height of Ti/Au made a complete electrical connection on the ZnO microwires of which diameter is around 2 ?m. A cross linked PMMA string was bridged between ZnO microwire and substrate for making good electrical connection. The contact resistance of ZnO microwire fabricated by this method was much lower than that of device fabricated by standard E-beam lithography and evaporation. This fabrication method is readily extendible to prepare nano scale electrodes on various micro sized materials and serves as a pathway for studying their mesoscopic transport phenomena.

Kim, Hakseong; Lee, Jinkyung; Yun, Hoyeol; Lee, Sang Wook

2013-03-01

119

Method for defoaming in gas purification systems  

Microsoft Academic Search

Disclosed is the method of defoaming an aqueous amine gas purification scrubbing solution by stripping gaseous contaminants from the scrubbing solution and then passing a side stream of from about 10% to about 20% of the scrubbing solution through a carbon filter.

1981-01-01

120

Method for cleaning sinter plant gas emissions  

SciTech Connect

A method for cleaning sinter plant gas emissions using a wet electrostatic precipitator system having separate recirculating wash liquor loops for the high voltage precipitator section and the pre-scrubber section. The system is operated with acidic washing liquor to avoid scaling and deposition of solids within the system.

Herman, S.T.; Jassund, S.A.; Mazer, M.R.

1981-03-17

121

Method for designing gas tag compositions  

DOEpatents

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.

Gross, K.C.

1995-04-11

122

Dispersion Of Evaporating Drops In A Vortex  

NASA Technical Reports Server (NTRS)

Report presents theoretical study of behavior of evaporating liquid drops entrained in annular cross section of long, coherent gas vortex. Dynamic and thermodynamic interactions described. Study contributes to understanding of evaporation and combustion of sprayed liquid fuels.

Bellan, Josette; Harstad, Kenneth G.

1992-01-01

123

Synthesis and characteristics of continuous mesoporous carbon films by a rapid solvent evaporation method  

NASA Astrophysics Data System (ADS)

Carbon films with a well-developed meso-porosity were synthesized directly by the carbonization of sulfuric-acid-treated P123 triblock copolymer/silica nanocomposite films, which were prepared from dip-coating technique through an association of sol-gel and evaporation-induced self-assembly process, and the residual silica was removed subsequently via HF-etching. P123 was employed as both structuring agent for self-assembly of tetraethyl orthosilicate and carbon precursor. The sulfuric acid solution was used as a catalyst for cross-linking of P123/silica in order to improve the carbon yield for the continuity of carbon films. Investigations by Field emission scanning electron microscopy (FESEM), X-ray diffraction, nitrogen adsorption measurement and transmission electron microscopy (TEM) indicate that the hybrid carbon/silica mesoporous films are preserved perfectly after the carbonization. When the silica is removed by acid treatment, continuous carbon films with an ordered symmetric structure are still kept well. The carbon films obtained are composed of carbon nanotubes with the diameter of around 6 nm, and the lengths of nanotubes affiliating with each other vary from about 100 nm to several micrometers, which were measured by FESEM and TEM.

Wang, Xiaoxian; Li, Tiehu; Ji, Yongbin; Ai, Yanling; Lin, Qilang

2008-12-01

124

Effect of drug properties on the release from CAP microspheres prepared by a solvent evaporation method.  

PubMed

Drugs with different water-solubility and molecular weights were microencapsulated in cellulose acetate phthalate, using an emulsion-solvent evaporation technique with a continuous oil-phase. The mean size of the particles was approximately 600 microns, and they were non-porous. The capacity of the microspheres to retain the drugs was evaluated by in vitro release studies in acidic medium. For low molecular weight compounds the release rates increased with solubility: for thiamin hydrochloride and phenacetin, a highly and a poorly soluble compound respectively, the percentages released at 60 min were 90 and 10%. Drugs with molecular weights above approximately 700 Da were retained in the microspheres. The above dependence on solubility was corroborated by release studies in ethanol, and by modelling the release of phenacetin in acidic media. Microspheres with a different polymer matrix, Eudragit RS PO, were also prepared by a similar technique, and these particles prolonged the release of thiamin for over 6 h, under simulated GI conditions. PMID:9972506

Silva, J P; Ferreira, J P

1999-01-01

125

Solid dispersion of carbamazepine in PVP K30 by conventional solvent evaporation and supercritical methods.  

PubMed

This study compares the physicochemical properties of carbamazepine (CBZ) solid dispersions prepared by either a conventional solvent evaporation versus a supercritical fluid process. Solid dispersions of carbamazepine in polyvinylpyrrolidone (PVP) K30 with either Gelucire 44/14 or Vitamin E TPGS, NF (d-alpha-tocopheryl polyethylene glycol 1000 succinate) were prepared and characterized by intrinsic dissolution, differential scanning calorimetry, powder X-ray diffraction and Fourier transform infrared spectroscopy. CBZ/PVP K30 and CBZ/PVP K30/TPGS solid dispersions showed increased dissolution rate. The best intrinsic dissolution rate (IDR) was obtained for supercritically processed CBZ/PVP K30 that was four-fold higher than pure CBZ. Thermograms of various solid dispersions did not show the melting peak of CBZ, indicating that CBZ was in amorphous form inside the carrier system. This was further confirmed by X-ray diffraction studies. Infrared spectroscopic studies showed interaction between CBZ and PVP K30 in solid dispersions. The amorphous state of CBZ coupled with presence of interaction between drug and PVP K30 suggests fewer, if any, stability problems. Because the supercritical-based process produced solid dispersions with IDR better than conventional solid dispersions augmented with amphiphilic carriers, stability issues associated with lipid carriers do not apply, which, in turn, implies easier scale up under current Good Manufacturing Practice for this technique. PMID:15019063

Sethia, S; Squillante, E

2004-03-19

126

Spectroscopic methods in gas hydrate research.  

PubMed

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

Rauh, Florian; Mizaikoff, Boris

2012-01-01

127

Hydrogen gas sensor and method of manufacture  

DOEpatents

A sensor for measuring the pressure of hydrogen gas in a nuclear reactor, and method of manufacturing the same. The sensor comprises an elongated tube of hydrogen permeable material which is connected to a pressure transducer through a feedthrough tube which passes through a wall at the boundary of the region in which hydrogen is present. The tube is pressurized and flushed with hydrogen gas at an elevated temperature during the manufacture of the sensor in order to remove all gasses other than hydrogen from the device.

McKee, John M. (Hinsdale, IL)

1991-01-01

128

Conversion method for gas streams containing hydrocarbons  

DOEpatents

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.

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

2000-01-01

129

MAGNESIUM AND SILICON ISOTOPIC COMPOSITIONS RECORDED DURING SIMULTANEOUS CRYSTALLIZATION AND EVAPORATION OF CMAS DROPLETS INTO AMBIENT SOLAR GAS.  

E-print Network

. Introduction. Activity-composition models were used to calculate vapor pressures over CaO-MgO- Al2O3-SiO2 (CMAS that the latter were ignored. In [2,3], techniques were developed for calculating both the vapor pres- sures over molten droplet having the composition of a high-temperature condensate during cooling and evaporation

Grossman, Lawrence

130

II. EvaporationII. Evaporation Vaporization  

E-print Network

II. EvaporationII. Evaporation Vaporization (mtorr) cm Line-of-sight transport Liu, UCD Phy250-1, 2011, NanoFab #12;Evaporation SourceEvaporation Source & compatibility #12;Evaporation SourceEvaporation Source Electron-beamInduction Electron-beamInduction Liu, UCD

Liu, Kai

131

Comparison of soil moisture retention characteristics obtained by the extended evaporation method and the pressure plate/sand box apparatus  

NASA Astrophysics Data System (ADS)

The water retention curve (WRC) characterizes the capacity of soil to hold water at specified soil matric potentials. It is a key property in any soil hydrologic application. To determine water retention data accurately and in turn use them to draw the whole curve by optimizing parameters of a proper soil hydraulic equation, it is of crucial importance to choose a suitable measurement procedure. For many years, the sand box-pressure plate apparatus are widely accepted as a reference laboratory procedure. To overcome shortcomings of the pressure plate, the evaporation method was introduced, besides many others. The method is not dependent on hydrostatic equilibrium conditions, thus allowing much quicker measurements, and yields the WRC in very high resolution. The method furthermore enables to quantify the unsaturated hydraulic conductivity function. We investigated a set of 40 fine-textured soils with both methods. The samples were packed from aggregated, dried and sieved material. Eight (-5, -10, -33, -100, -400, -700,-1000 and -1500kPa) water retention data points were obtained from sand box-pressure plate apparatus. Evaporation measurements were performed with the commercial apparatus HYPROP by UMS GmbH, Munich, applying the extended method, which yields water retention data in the range from 0 to -500kPa. We found that the sand box-pressure plate method lead to immediate drainage of water, whereas in HYPROP water started to drain only after reaching an air-entry point of pF 1.2-1.3. Accordingly, HYPROP gave higher water contents until pF 2, compared to the sand box/pressure plate apparatus, but from this point on both curves begin to be close and around the field capacity (pF 2.5) they overlap. Both methods show that the textural pore system starts to drain much later, around pF 3.5. We hypothesize that the reason for the different drainage behaviour of the interaggrate pore system lies in the saturation procedure. For HYPROP, samples were saturated under vacuum, yielding 100% saturation, whereas for the traditional method saturation took place by capillary uptake.

Öztürk, Hasan S.; Durner, Wolfgang; Haghverdi, Amir; Walter, Birgit

2013-04-01

132

Modelling non-equilibrium secondary organic aerosol formation and evaporation with the aerosol dynamics, gas- and particle-phase chemistry kinetic multilayer model ADCHAM  

NASA Astrophysics Data System (ADS)

We have developed the novel Aerosol Dynamics, gas- and particle-phase chemistry model for laboratory CHAMber studies (ADCHAM). The model combines the detailed gas-phase Master Chemical Mechanism version 3.2 (MCMv3.2), an aerosol dynamics and particle-phase chemistry module (which considers acid-catalysed oligomerization, heterogeneous oxidation reactions in the particle phase and non-ideal interactions between organic compounds, water and inorganic ions) and a kinetic multilayer module for diffusion-limited transport of compounds between the gas phase, particle surface and particle bulk phase. In this article we describe and use ADCHAM to study (1) the evaporation of liquid dioctyl phthalate (DOP) particles, (2) the slow and almost particle-size-independent evaporation of ?-pinene ozonolysis secondary organic aerosol (SOA) particles, (3) the mass-transfer-limited uptake of ammonia (NH3) and formation of organic salts between ammonium (NH4+) and carboxylic acids (RCOOH), and (4) the influence of chamber wall effects on the observed SOA formation in smog chambers. ADCHAM is able to capture the observed ?-pinene SOA mass increase in the presence of NH3(g). Organic salts of ammonium and carboxylic acids predominantly form during the early stage of SOA formation. In the smog chamber experiments, these salts contribute substantially to the initial growth of the homogeneously nucleated particles. The model simulations of evaporating ?-pinene SOA particles support the recent experimental findings that these particles have a semi-solid tar-like amorphous-phase state. ADCHAM is able to reproduce the main features of the observed slow evaporation rates if the concentration of low-volatility and viscous oligomerized SOA material at the particle surface increases upon evaporation. The evaporation rate is mainly governed by the reversible decomposition of oligomers back to monomers. Finally, we demonstrate that the mass-transfer-limited uptake of condensable organic compounds onto wall-deposited particles or directly onto the Teflon chamber walls of smog chambers can have a profound influence on the observed SOA formation. During the early stage of the SOA formation the wall-deposited particles and walls themselves serve as an SOA sink from the air to the walls. However, at the end of smog chamber experiments the semi-volatile SOA material may start to evaporate from the chamber walls. With these four model applications, we demonstrate that several poorly quantified processes (i.e. mass transport limitations within the particle phase, oligomerization, heterogeneous oxidation, organic salt formation, and chamber wall effects) can have a substantial influence on the SOA formation, lifetime, chemical and physical particle properties, and their evolution. In order to constrain the uncertainties related to these processes, future experiments are needed in which as many of the influential variables as possible are varied. ADCHAM can be a valuable model tool in the design and analysis of such experiments.

Roldin, P.; Eriksson, A. C.; Nordin, E. Z.; Hermansson, E.; Mogensen, D.; Rusanen, A.; Boy, M.; Swietlicki, E.; Svenningsson, B.; Zelenyuk, A.; Pagels, J.

2014-08-01

133

Thin film deposition and characterization of pure and iron-doped electron-beam evaporated tungsten oxide for gas sensors  

Microsoft Academic Search

Pure tungsten oxide (WO3) and iron-doped (10at.%) tungsten oxide (WO3:Fe) nanostructured thin films were prepared using a dual crucible Electron Beam Evaporation (EBE) technique. The films were deposited at room temperature under high vacuum onto glass as well as alumina substrates and post-heat treated at 300°C for 1h. Using Raman spectroscopy the as-deposited WO3 and WO3:Fe films were found to

Tuquabo Tesfamichael; Masashi Arita; Thor Bostrom; John Bell

2010-01-01

134

Method to measure time-dependent scattering cross sections of particles evaporating in a laser beam  

Microsoft Academic Search

We develop a new method of measuring the time-dependent solid angle scattering cross section for detection (Csca(t)) of individual particles flowing across a Gaussian laser beam. This method is based on the principle that the normalized derivative of the scattering signal (S? \\/S) measured by an instrument can be decomposed into the normalized derivative of the incident irradiance (I ?

Nobuhiro Moteki; Yutaka Kondo

2008-01-01

135

Method and apparatus for producing synthesis gas  

DOEpatents

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.

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

2010-03-03

136

CONDENSATION AND EVAPORATION FOR THERMALLY UNEQUILIBRATED PHASES  

E-print Network

CONDENSATION AND EVAPORATION FOR THERMALLY UNEQUILIBRATED PHASES R. A. Marcus1 , A. V. Fedkin2-K) equation for the rate of condensation of a gas or evaporation of a solid or liquid is used for systems, and apply it to shock wave- induced evaporation and condensation of a chondrule precursor. Theory

Grossman, Lawrence

137

Evaporative Cooler  

NSDL National Science Digital Library

Explore the concept of evaporative cooling through a hands-on experiment. Use a wet cloth and fan to model an air-conditioner and use temperature and relative humidity sensors to collect data. Then digitally plot the data using graphs in the activity. In an optional extension, make your own modifications to improve the cooler's efficiency.

Consortium, The C.

2011-12-12

138

Method for controlling gas metal arc welding  

DOEpatents

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.

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

1989-01-01

139

Method for controlling gas metal arc welding  

DOEpatents

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.

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

1987-08-10

140

A new method for measuring heat of electron evaporation from thermionic energy converter emitter  

Microsoft Academic Search

The method described is based on measuring the rate of emitter cooling after the thermionic energy converter is switched from the open-circuit steady-state operation into the current mode of operation at a constant input power. The rate of change in useful voltage across the electrodes is measured for 0.5 s. During this time useful voltage changes, depending on the current

Iu. N. Dzhashiashvili; V. Z. Kaibyshev

1989-01-01

141

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

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

142

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

Microsoft Academic Search

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., 0.1 mL{sub fuel}\\/L{sub gas}, 1 x 10 droplets\\/L{sub gas} for stoichiometric fuel loading at ambient conditions) can result in droplet-droplet interactions which

S. S. Goldsborough; M. V. Johnson; G. S. Zhu; S. K. Aggarwal

2011-01-01

143

Vacuum flash evaporated polymer composites  

DOEpatents

A method for fabrication of polymer composite layers in a vacuum is disclosed. More specifically, the method of dissolving salts in a monomer solution, vacuum flash evaporating the solution, condensing the flash evaporated solution as a liquid film, and forming the condensed liquid film into a polymer composite layer on a substrate is disclosed.

Affinito, J.D.; Gross, M.E.

1997-10-28

144

Vacuum flash evaporated polymer composites  

DOEpatents

A method for fabrication of polymer composite layers in a vacuum is disclosed. More specifically, the method of dissolving salts in a monomer solution, vacuum flash evaporating the solution, condensing the flash evaporated solution as a liquid film, and forming the condensed liquid film into a polymer composite layer on a substrate is disclosed.

Affinito, John D. (Kennewick, WA); Gross, Mark E. (Pasco, WA)

1997-01-01

145

Streamer Evaporation  

NASA Technical Reports Server (NTRS)

Evaporation is the consequence of heating near the top of streamers in ideal Magnetohydrodynamics (MHD) models, where the plasma is weakly contained by the magnetic field. Heating causes slow opening of field lines and release of new solar wind. It was discovered in simulations and, due to the absence of loss mechanisms, the ultimate end point is the complete evaporation of the streamer. Of course streamers do not behave in this way because there are losses by thermal conduction and radiation. Physically, heating is also expected to depend on ambient conditions. We use our global MHD model with thermal conduction to examine the effect of changing the heating scale height. We also apply and extend an analytic model of streamers developed by Pneuman (1968) to show that steady streamers are unable to contain plasma for temperatures near the cusp greater than approximately 2 x 10(exp 6) K.

Suess, S. T.; Wang, A.-H.; Wu, S. T.; Nerney, S. F.

1998-01-01

146

Multiresidue determination of 256 pesticides in lavandin essential oil by LC/ESI/sSRM: advantages and drawbacks of a sampling method involving evaporation under nitrogen.  

PubMed

The determination of 256 multiclass pesticides in lavandin essential oil has been performed by liquid chromatography-electrospray ionization tandem mass spectrometry using the scheduled selected reaction monitoring mode available on a quadrupole-linear ion trap mass spectrometer. With the aim of improving the limits of quantification (LOQs) of the target molecules, a sampling step based on evaporation of the essential oil under a nitrogen flow assisted by controlled heating was tested. The LOQs determined in this case were compared with the values obtained with the classic dilution preparation method. With sampling by dilution, 247 pesticides were detected and quantified at low concentration, with 74 % of the pesticides having LOQs of 10 ?g L(-1) or less. With the evaporation method, a global improvement of the LOQs was observed, with lower LOQs for 92 active substances and LOQs of 10 ?g L(-1) or less for 82.8 % of the pesticides. Almost twice as many active substances had an LOQ of 1 ?g L(-1) or less when the evaporation method was used. Some pesticides exhibited poor recovery or high variance caused by volatilization or degradation during the evaporation step. This behavior was evidenced by the case of thiophanate-methyl, which is degraded to carbendazim. PMID:24366405

Fillâtre, Yoann; Rondeau, David; Daguin, Antoine; Jadas-Hecart, Alain; Communal, Pierre-Yves

2014-02-01

147

Release Kinetic Studies of Aspirin Microcapsules from Ethyl Cellulose, Cellulose Acetate Phthalate and their Mixtures by Emulsion Solvent Evaporation Method  

PubMed Central

The present study was oriented towards microencapsulation of aspirin and the study of its release kinetics. The desired encapsulation was achieved by emulsion solvent evaporation method using ethyl cellulose (EC), cellulose acetate phthalate (CAP) and their mixture (1:1) of polymeric constituents. Characterization of the formulations was performed by size, shape, drug loading efficiency and in-vitro drug release analysis. The in-vitro release profiles from different polymeric microcapsules were applied on different kinetic models. The prepared microcapsules were found free flowing and almost spherical in shape with particle sizes ranging from 300–700?m, having a loading efficiency of 75–85%. The best fit model with the highest correlation coefficient was observed in Higuchi model, indicating diffusion controlled principle. The n value obtained from Korsemeyer-Peppas model varied between 0.5–0.7, confirming that the mechanism of drug release was diffusion controlled. Comparative studies revealed that the release of aspirin from EC microcapsules was slower as compared to that of CAP and their binary mixture. PMID:21179372

Dash, Vikas; Mishra, Sujeet K.; Singh, Manoj; Goyal, Amit K.; Rath, Goutam

2010-01-01

148

Method and apparatus for the cooling of natural gas  

Microsoft Academic Search

A method is claimed for cooling natural gas in a system in which the natural gas contains components other than methane which are separable by dewpoint condensation and the natural gas is available from a source, e.g. a well, at an elevated pressure. In accordance with the present invention, the natural gas is initially expanded in a work-producing expansion turbine

Strass

1982-01-01

149

Comparison of methods for measuring gas-particle partitioning of semivolatile compounds  

NASA Astrophysics Data System (ADS)

This work demonstrates several difficulties associated with sampling semivolatile aerosols. Gas-particle partition coefficients ( Kp=[ F/TSP]/ A) of semivolatile PAHs and alkanes were estimated from chamber tests using four different sampling methods: filter-adsorbent (FA), filter-filter-adsorbent (FFA), Denuder-filter-adsorbent (DFA), and electrostatic precipitator-Adsorbent (EA). The FA, FFA, and EA sampling methods estimated Kp accurately for high concentrations of PAHs in diesel engine exhaust aerosol. The FA sampler, which used a Teflon Zeflour filter, was biased by filter adsorption of alkane gases sampled at lower concentrations, whereas the FFA sampler, which used a Teflon coated glass fiber filter, was biased by particle evaporation during the same tests. The EA sampler introduced small biases at low concentrations due to chemical artifacts from the corona, non-ideal particle collection, and evaporative loss of collected particles. The DFA sampler was biased by particle losses in the denuder for PAHs in diesel exhaust aerosol, but gave accurate estimates of Kp for alkanes measured at lower concentrations. Results from this research show that none of the methods tested was able to measure gas-particle partition coefficients accurately for each series of compounds under all sampling situations.

Volckens, John; Leith, David

150

Method of detecting oxygen in a gas  

NASA Technical Reports Server (NTRS)

The presence of oxygen in a gas is detected by contacting an article, such as a film, comprising poly(ethylenenaphthalene-dicarboxylate) with a gas and simultaneously exposing the article to ultraviolet light. The article is subsequently heated and the presence of oxygen in the gas is indicated by thermoluminescence.

Hendricks, H. D. (inventor)

1973-01-01

151

Water augmented indirectly-fired gas turbine systems and method  

DOEpatents

An indirectly-fired gas turbine system utilizing water augmentation for increasing the net efficiency and power output of the system is described. Water injected into the compressor discharge stream evaporatively cools the air to provide a higher driving temperature difference across a high temperature air heater which is used to indirectly heat the water-containing air to a turbine inlet temperature of greater than about 1,000.degree. C. By providing a lower air heater hot side outlet temperature, heat rejection in the air heater is reduced to increase the heat recovery in the air heater and thereby increase the overall cycle efficiency.

Bechtel, Thomas F. (Lebanon, PA); Parsons, Jr., Edward J. (Morgantown, WV)

1992-01-01

152

Methods and Apparatus for Assembling Gas Turbine Engines.  

National Technical Information Service (NTIS)

A method for assembling a gas turbine engine includes coupling an outer structure within the gas turbine engine, wherein the outer structure includes a socket extending from a radially inner surface of the outer structure, and coupling an inner structure ...

R. P. Czachor

2004-01-01

153

Method and apparatus for manufacturing gas tags  

DOEpatents

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.

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

1996-01-01

154

Method and apparatus for manufacturing gas tags  

DOEpatents

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.

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

1996-12-17

155

JV TASK 7-FIELD APPLICATION OF THE FREEZE-THAW/EVAPORATION (FTE) PROCESS FOR THE TREATMENT OF NATURAL GAS PRODUCED WATER IN WYOMING  

SciTech Connect

The freeze-thaw/evaporation (FTE{reg_sign}) process treats oil and gas produced water so that the water can be beneficially used. The FTE{reg_sign} process is the coupling of evaporation and freeze-crystallization, and in climates where subfreezing temperatures seasonally occur, this coupling improves process economics compared to evaporation alone. An added benefit of the process is that water of a quality suited for a variety of beneficial uses is produced. The evolution, from concept to successful commercial deployment, of the FTE{reg_sign} process for the treatment of natural gas produced water has now been completed. In this document, the histories of two individual commercial deployments of the FTE{reg_sign} process are discussed. In Wyoming, as in many other states, the permitting and regulation of oil and gas produced water disposal and/or treatment facilities depend upon the legal relationship between owners of the facility and the owners of wells from which the water is produced. An ''owner-operated'' facility is regulated by the Wyoming Oil and Gas Conservation Commission (WOGCC) and is defined as an entity which only processes water which comes from the wells in fields of which they have an equity interest. However, if a facility processes water from wells in which the owners of the facility have no equity interest, the facility is considered a ''commercial'' facility and is permitted and regulated by the Wyoming Department of Environmental Quality. For this reason, of the two commercial FTE{reg_sign} process deployments discussed in this document, one is related to an ''owner-operated'' facility, and the other relates to a ''commercial'' facility. Case 1 summarizes the permitting, design, construction, operation, and performance of the FTE{reg_sign} process at an ''owner-operated'' facility located in the Jonah Field of southwestern Wyoming. This facility was originally owned by the McMurry Oil Company and was later purchased by the Alberta Energy Company (now EnCana). Case 2 summarizes the permitting, design, construction, operation, and performance at a ''commercial'' FTE{reg_sign} facility located in the Great Divide Basin of south central Wyoming. Permits required for the construction and operation of each facility are described in detail. The respective qualities of each feed water, treated water, and concentrate stream are presented along with the relative yields of treated water and concentrate at each facility. Treated water from the owner-operated facility has been beneficially used in drilling and dust abatement, and treated water from the commercial facility has been used for dust abatement, construction, and land application. The permitting requirements and evaluation of beneficial use of the water at each facility are discussed. The results of this research confirm that the FTE{reg_sign} process is economic at a commercial-scale for the treatment and disposal of natural gas produced water in Wyoming. Further, the treated water produced from the process is of a quality suitable for beneficial uses such as irrigation, drilling mix, wildlife or livestock watering, and/or dust abatement on local roads.

James A. Sorensen; John Boysen; Deidre Boysen; Tim Larson

2002-10-01

156

Synthesis Methods, Microscopy Characterization and Device Integration of Nanoscale Metal Oxide Semiconductors for Gas Sensing  

PubMed Central

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 activation energies for the catalyst-assisted systems. PMID:22408484

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

2009-01-01

157

Olive mill wastewater evaporation management using PCA method Case study of natural degradation in stabilization ponds (Sfax, Tunisia).  

PubMed

Olive mill wastewater (OMW) evaporation ponds management was investigated in five serial evaporation open-air multiponds of 50 ha located in Sfax (Tunisia). Physico-chemical parameters and microbial flora evolution were considered. Empirical models describing the OMW characteristic changes with the operation time were established and Principal Component Analysis (PCA) described the correlation between physico-chemical and biological parameters. COD, BOD, total solids, polyphenols and electrical conductivity exhibited first-order models. Four groups exhibited high correlations. The first included temperature, density, COD, TSS, TS, BOD, VS, TOC, TKN, polyphenols and minerals. The second group was made up of yeasts and moulds. The third group was established with phenolic compounds, total sugars, fats, total phosphorous, NH(4)(+) and pH. The fourth group was constituted by exclusively aerobic bacteria. Bacterial-growth toxic effect was exhibited by high organic load, ash content and polyphenols, whereas moulds and yeasts were more adapted to OMW. During the storage, all the third group parameter values decreased and were inversely related to the others. In the last pond, COD, BOD, TS and TSS rates were reduced by 40%, 50%, 50% and 75% respectively. The evaporation and the biological activity were the main processes acting, predicting the OMW behavior during evaporation in air-open ponds. PMID:20036054

Jarboui, Raja; Sellami, Fatma; Azri, Chafai; Gharsallah, Néji; Ammar, Emna

2010-04-15

158

A numerical method for integrating the kinetic equations of droplet spectra evolution by condensation/evaporation and by coalescence/breakup processes  

NASA Astrophysics Data System (ADS)

An extension of the method of moments is developed for the numerical integration of the kinetic equations of droplet spectra evolution by condensation/evaporation and by coalescence/breakup processes. The number density function n sub k (x,t) in each separate droplet packet between droplet mass grid points (x sub k, x sub k+1) is represented by an expansion in orthogonal polynomials with a given weighting function. In this way droplet number concentrations, liquid water contents and other moments in each droplet packet are conserved and the problem of solving the kinetic equations is replaced by one of solving a set of coupled differential equations for the number density function moments. The method is tested against analytic solutions of the corresponding kinetic equations. Numerical results are obtained for different coalescence/breakup and condensation/evaporation kernels and for different initial droplet spectra. Also droplet mass grid intervals, weighting functions, and time steps are varied.

Emukashvily, I. M.

1982-03-01

159

A numerical method for integrating the kinetic equations of droplet spectra evolution by condensation/evaporation and by coalescence/breakup processes  

NASA Technical Reports Server (NTRS)

An extension of the method of moments is developed for the numerical integration of the kinetic equations of droplet spectra evolution by condensation/evaporation and by coalescence/breakup processes. The number density function n sub k (x,t) in each separate droplet packet between droplet mass grid points (x sub k, x sub k+1) is represented by an expansion in orthogonal polynomials with a given weighting function. In this way droplet number concentrations, liquid water contents and other moments in each droplet packet are conserved and the problem of solving the kinetic equations is replaced by one of solving a set of coupled differential equations for the number density function moments. The method is tested against analytic solutions of the corresponding kinetic equations. Numerical results are obtained for different coalescence/breakup and condensation/evaporation kernels and for different initial droplet spectra. Also droplet mass grid intervals, weighting functions, and time steps are varied.

Emukashvily, I. M.

1982-01-01

160

Streamer Evaporation  

NASA Technical Reports Server (NTRS)

Evaporation is the consequence of slow plasma heating near the tops of streamers where the plasma is only weakly contained by the magnetic field. The form it takes is the slow opening of field lines at the top of the streamer and transient formation of new solar wind. It was discovered in polytropic model calculations, where due to the absence of other energy loss mechanisms in magnetostatic streamers, its ultimate endpoint is the complete evaporation of the streamer. This takes, for plausible heating rates, weeks to months in these models. Of course streamers do not behave this way, for more than one reason. One is that there are losses due to thermal conduction to the base of the streamer and radiation from the transition region. Another is that streamer heating must have a characteristic time constant and depend on the ambient physical conditions. We use our global Magnetohydrodynamics (MHD) model with thermal conduction to examine a few examples of the effect of changing the heating scale height and of making ad hoc choices for how the heating depends on ambient conditions. At the same time, we apply and extend the analytic model of streamers, which showed that streamers will be unable to contain plasma for temperatures near the cusp greater than about 2xl0(exp 6) K. Slow solar wind is observed to come from streamers through transient releases. A scenario for this that is consistent with the above physical process is that heating increases the near-cusp temperature until field lines there are forced open. The subsequent evacuation of the flux tubes by the newly forming slow wind decreases the temperature and heating until the flux tubes are able to reclose. Then, over a longer time scale, heating begins to again refill the flux tubes with plasma and increase the temperature until the cycle repeats itself. The calculations we report here are first steps towards quantitative evaluation of this scenario.

Suess, Steven T.; Wang, A. H.; Wu, Shi T.; Nerney, S.

1998-01-01

161

Preparation of spinel ZnGa 2O 4 films on MgO substrates by the solvent evaporation epitaxy method  

Microsoft Academic Search

Oriented thin films of ZnGa2O4 have been obtained on an MgO(001) substrate by the solvent evaporation epitaxy method. The results of EPMA suggest that the ratio of Zn to Ga is almost stoichiometric and nearly all of the solvent of PbF2 is removed. The crystal structure of the film is cubic spinel with a lattice constant of a = 8.33(3)

Zheng Yan; Masayoshi Koike; Humihiko Takei

1996-01-01

162

Method and apparatus for processing a natural gas stream  

Microsoft Academic Search

This is a method and apparatus for processing a natural gas stream. The apparatus consists of at least three adsorbent beds, with each bed passing consecutively through an adsorption cycle, an open-type heating cycle, and an open-type cooling cycle. The gas stream is first separated into two portions so that a stripped gas leaves the first bed. The second portion

E. L. McCarthy; R. E. McMinn; M. S. Worley

1966-01-01

163

Analytical tests for numerical methods in gas dynamics  

Microsoft Academic Search

A verification of the accuracy of various numerical methods in gas dynamics can be effectively achieved by obtaining exact solutions to gas dynamics equations. Several types of steady and unsteady plane and three-dimensional flows of inviscid gas are considered for which analytical representations have been obtained. The discussion covers triple- and double-wave potential flows, exact solutions with sub- and supersonic

A. F. Sidorov

1982-01-01

164

Temperature Gradient Method for Continuous Countercurrent Gas–Liquid Chromatography  

Microsoft Academic Search

Continuous countercurrent gas–liquid chromatography (CCGLC), where the gas and liquid phases move countercurrently and the sample can be introduced continuously, is a method suitable for separating binary sample systems. The flow ratio of the gas and liquid phases (G\\/L) in CCGLC should be between the partition coefficients of the two components to be separated. However, the larger the difference between

Katsuya Sato; Osamu Motokawa; Katsunori Watabe; Toshihide Ihara; Toshiyuki Hobo

1993-01-01

165

High energy transport gas and method to transport same  

US Patent & Trademark Office Database

A high energy transport gas and a method to transport the high energy transport gas are used to increase the energy content of a pipeline and other vessels that are designed to carry natural gas under ambient conditions, in a compressed state or in a liquefied state. Methane and other gases are used as the feedstock, with methane from natural gas fields, coal beds or derived from hydrogen reacting with coal being primary energy sources. Also, this gas and method can provide an abundant source for hydrogen production, and the energy from hydrogen can be used for fuel cell applications that generate electricity and power motor vehicles. This gas and method are capable of increasing the energy capacity of current natural gas pipelines and other storage and transport vessels.

2012-10-02

166

Measurement of leaf hydraulic conductance and stomatal conductance and their responses to irradiance and dehydration using the Evaporative Flux Method (EFM).  

PubMed

Water is a key resource, and the plant water transport system sets limits on maximum growth and drought tolerance. When plants open their stomata to achieve a high stomatal conductance (gs) to capture CO2 for photosynthesis, water is lost by transpiration(1,2). Water evaporating from the airspaces is replaced from cell walls, in turn drawing water from the xylem of leaf veins, in turn drawing from xylem in the stems and roots. As water is pulled through the system, it experiences hydraulic resistance, creating tension throughout the system and a low leaf water potential (?(leaf)). The leaf itself is a critical bottleneck in the whole plant system, accounting for on average 30% of the plant hydraulic resistance(3). Leaf hydraulic conductance (K(leaf) = 1/ leaf hydraulic resistance) is the ratio of the water flow rate to the water potential gradient across the leaf, and summarizes the behavior of a complex system: water moves through the petiole and through several orders of veins, exits into the bundle sheath and passes through or around mesophyll cells before evaporating into the airspace and being transpired from the stomata. K(leaf) is of strong interest as an important physiological trait to compare species, quantifying the effectiveness of the leaf structure and physiology for water transport, and a key variable to investigate for its relationship to variation in structure (e.g., in leaf venation architecture) and its impacts on photosynthetic gas exchange. Further, K(leaf) responds strongly to the internal and external leaf environment(3). K(leaf) can increase dramatically with irradiance apparently due to changes in the expression and activation of aquaporins, the proteins involved in water transport through membranes(4), and K(leaf) declines strongly during drought, due to cavitation and/or collapse of xylem conduits, and/or loss of permeability in the extra-xylem tissues due to mesophyll and bundle sheath cell shrinkage or aquaporin deactivation(5-10). Because K(leaf) can constrain gs and photosynthetic rate across species in well watered conditions and during drought, and thus limit whole-plant performance they may possibly determine species distributions especially as droughts increase in frequency and severity(11-14). We present a simple method for simultaneous determination of K(leaf) and gs on excised leaves. A transpiring leaf is connected by its petiole to tubing running to a water source on a balance. The loss of water from the balance is recorded to calculate the flow rate through the leaf. When steady state transpiration (E, mmol • m(-2) • s(-1)) is reached, gs is determined by dividing by vapor pressure deficit, and K(leaf) by dividing by the water potential driving force determined using a pressure chamber (K(leaf)= E /- ??(leaf), MPa)(15). This method can be used to assess K(leaf) responses to different irradiances and the vulnerability of K(leaf) to dehydration(14,16,17). PMID:23299126

Sack, Lawren; Scoffoni, Christine

2012-01-01

167

Preparation and properties of transparent conducting zinc oxide and aluminium-doped zinc oxide films prepared by evaporating method  

Microsoft Academic Search

Undoped and aluminium-doped zinc oxide films have been prepared by thermal evaporation of zinc acetate [Zn(CH3COO)2 2H2O] and aluminium chloride [AlCl3] onto a heated glass substrate. The structural and optoelectrical properties of the films have been studied. The effects of heat treatment for the as-deposited films in air and vaccum are investigated. Highly transparent films with conductivity as low as

Jin Ma; Feng Ji; Hong-lei Ma; Shu-ying Li

2000-01-01

168

Optical and electronic properties of transparent conducting ZnO and ZnO:Al films prepared by evaporating method  

Microsoft Academic Search

Undoped and Aluminium-doped Zinc oxide films have been prepared by thermal evaporation of zinc acetate (Zn(CH3COO)2·2H2O] and aluminium chloride (AlCl3) onto a heated glass substrate. The structural, optical and electrical properties of the films have been studied. The effects of heat treatment for the as-deposited films in air and vacuum are investigated. Over 80% transmittance films with conductivity as low

M. Jin; Ji Feng; Zhang De-heng; Ma Hong-lei; Li Shu-ying

1999-01-01

169

SEWAGE DISPOSAL BY EVAPORATION-TRANSPIRATION  

EPA Science Inventory

One of the methods for on-site disposal of wastewater from individual homes is by evaporation. Two types of evaporative disposal systems have been investigated in this study; evapo-transpiration (ET) beds and mechanical evaporation units. Twenty nine test lysimeters of 0.22 cubic...

170

DWPF RECYCLE EVAPORATOR FLOWSHEET EVALUATION (U)  

SciTech Connect

The Defense Waste Processing Facility (DWPF) converts the high level waste slurries stored at the Savannah River Site into borosilicate glass for long-term storage. The vitrification process results in the generation of approximately five gallons of dilute recycle streams for each gallon of waste slurry vitrified. This dilute recycle stream is currently transferred to the H-area Tank Farm and amounts to approximately 1,400,000 gallons of effluent per year. Process changes to incorporate salt waste could increase the amount of effluent to approximately 2,900,000 gallons per year. The recycle consists of two major streams and four smaller streams. The first major recycle stream is condensate from the Chemical Process Cell (CPC), and is collected in the Slurry Mix Evaporator Condensate Tank (SMECT). The second major recycle stream is the melter offgas which is collected in the Off Gas Condensate Tank (OGCT). The four smaller streams are the sample flushes, sump flushes, decon solution, and High Efficiency Mist Eliminator (HEME) dissolution solution. These streams are collected in the Decontamination Waste Treatment Tank (DWTT) or the Recycle Collection Tank (RCT). All recycle streams are currently combined in the RCT and treated with sodium nitrite and sodium hydroxide prior to transfer to the tank farm. Tank Farm space limitations and previous outages in the 2H Evaporator system due to deposition of sodium alumino-silicates have led to evaluation of alternative methods of dealing with the DWPF recycle. One option identified for processing the recycle was a dedicated evaporator to concentrate the recycle stream to allow the solids to be recycled to the DWPF Sludge Receipt and Adjustment Tank (SRAT) and the condensate from this evaporation process to be sent and treated in the Effluent Treatment Plant (ETP). In order to meet process objectives, the recycle stream must be concentrated to 1/30th of the feed volume during the evaporation process. The concentrated stream must be pumpable to the DWPF SRAT vessel and should not precipitate solids to avoid fouling the evaporator vessel and heat transfer coils. The evaporation process must not generate excessive foam and must have a high Decontamination Factor (DF) for many species in the evaporator feed to allow the condensate to be transferred to the ETP. An initial scoping study was completed in 2001 to evaluate the feasibility of the evaporator which concluded that the concentration objectives could be met. This initial study was based on initial estimates of recycle concentration and was based solely on OLI modeling of the evaporation process. The Savannah River National Laboratory (SRNL) has completed additional studies using simulated recycle streams and OLI{reg_sign} simulations. Based on this work, the proposed flowsheet for the recycle evaporator was evaluated for feasibility, evaporator design considerations, and impact on the DWPF process. This work was in accordance with guidance from DWPF-E and was performed in accordance with the Technical Task and Quality Assurance Plan.

Stone, M

2005-04-30

171

Heterodyne method for high specificity gas detection.  

NASA Technical Reports Server (NTRS)

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.

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

172

Lattice gas methods for computational aeroacoustics  

NASA Technical Reports Server (NTRS)

This paper presents the lattice gas solution to the category 1 problems of the ICASE/LaRC Workshop on Benchmark Problems in Computational Aeroacoustics. The first and second problems were solved for Delta t = Delta x = 1, and additionally the second problem was solved for Delta t = 1/4 and Delta x = 1/2. The results are striking: even for these large time and space grids the lattice gas numerical solutions are almost indistinguishable from the analytical solutions. A simple bug in the Mathematica code was found in the solutions submitted for comparison, and the comparison plots shown at the end of this volume show the bug. An Appendix to the present paper shows an example lattice gas solution with and without the bug.

Sparrow, Victor W.

1995-01-01

173

Flue gas desulfurization method and apparatus  

DOEpatents

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. 5 figs.

Madden, D.A.; Farthing, G.A.

1998-09-29

174

Flue gas desulfurization method and apparatus  

DOEpatents

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. 5 figs.

Madden, D.A.; Farthing, G.A.

1998-08-18

175

Method of immobilizing carbon dioxide from gas streams  

Microsoft Academic Search

This invention is a method for rapidly and continuously immobilizing carbon dioxide contained in various industrial off-gas streams, the carbon dioxide being immobilized as dry, stable, and substantially water-insoluble particulates. Briefly, the method comprises passing the gas stream through a fixed or fluidized bed of hydrated barium hydroxide to remove and immobilize the carbon dioxide by converting the bed to

David W. Holladay; Gary L. Haag

1979-01-01

176

Method of immobilizing carbon dioxide from gas streams  

Microsoft Academic Search

This invention comprises a method for rapidly and continuously immobilizing carbon dioxide contained in various industrial off-gas streams, the carbon dioxide being immobilized as dry, stable, and substantially water-insoluble particulates. Briefly, the method comprises passing the gas stream through a fixed or fluidized bed of hydrated barium hydroxide to remove and immobilize the carbon dioxide by converting the bed to

D. W. Holladay; G. L. Haag

1979-01-01

177

Methods of estimating oil and gas resources  

Microsoft Academic Search

Assessment of undiscovered oil and gas potentials can be made and presented in a probability format reflecting the inherent uncertainties and risks. A cumulative probability curve shows the chances of occurrence of possible hydrocarbon volumes, the risk that there is little or no potential, the average or expected value, and the highside potential. Such a surve can be drawn directly

D. A. White; H. M. Gehman

1979-01-01

178

Endwall Treatment and Method for Gas Turbine  

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

179

Evaluation of two gas-dilution methods for instrument calibration  

NASA Technical Reports Server (NTRS)

Two gas dilution methods were evaluated for use in the calibration of analytical instruments used in air pollution studies. A dual isotope fluorescence carbon monoxide analyzer was used as the transfer standard. The methods are not new but some modifications are described. The rotary injection gas dilution method was found to be more accurate than the closed loop method. Results by the two methods differed by 5 percent. This could not be accounted for by the random errors in the measurements. The methods avoid the problems associated with pressurized cylinders. Both methods have merit and have found a place in instrument calibration work.

Evans, A., Jr.

1977-01-01

180

Characterization of sulfur compounds in whisky by full evaporation dynamic headspace and selectable one-dimensional/two-dimensional retention time locked gas chromatography-mass spectrometry with simultaneous element-specific detection.  

PubMed

A method is described for characterization of sulfur compounds in unaged and aged whisky. The method is based on full evaporation dynamic headspace (FEDHS) of 100 ?L of whisky samples followed by selectable one-dimensional ((1)D) or two-dimensional ((2)D) retention-time-locked (RTL) gas chromatography (GC)-mass spectrometry (MS) with simultaneous element-specific detection using a sulfur chemiluminescence detector (SCD) and a nitrogen chemiluminescence detector (NCD). Sequential heart-cuts of the 16 sulfur fractions were used to identify each individual sulfur compound in the unaged whisky. Twenty sulfur compounds were positively identified by a MS library search, linear retention indices (LRI), and formula identification using MS calibration software. Additionally eight formulas were also identified for unknown sulfur compounds. Simultaneous heart-cuts of the 16 sulfur fractions were used to produce the (2)D RTL GC-SCD chromatograms for principal component analysis. PCA of the (2)D RTL GC-SCD data clearly demonstrated the difference between unaged and aged whisky, as well as two different whisky samples. Fourteen sulfur compounds could be characterized as key sulfur compounds responsible for the changes in the aging step and/or the difference between two kinds of whisky samples. The determined values of the key sulfur compounds were in the range of 0.3-210 ng mL(-1) (RSD: 0.37-12%, n=3). PMID:23182286

Ochiai, Nobuo; Sasamoto, Kikuo; MacNamara, Kevin

2012-12-28

181

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

Microsoft Academic Search

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

Akira Tsuchiyama; Shogo Tachibana; Toshio Takahashi

1999-01-01

182

Method for nonlinear optimization for gas tagging and other systems  

DOEpatents

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.

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

1998-01-01

183

System and method for producing substitute natural gas from coal  

DOEpatents

The present invention provides a system and method for producing substitute natural gas and electricity, while mitigating production of any greenhouse gasses. The system includes a hydrogasification reactor, to form a gas stream including natural gas and a char stream, and an oxygen burner to combust the char material to form carbon oxides. The system also includes an algae farm to convert the carbon oxides to hydrocarbon material and oxygen.

Hobbs, Raymond (Avondale, AZ)

2012-08-07

184

Method for hot gas cooling and gaseous contaminant removal  

Microsoft Academic Search

Method and apparatus are disclosed for cooling a process gas stream having a temperature in the range from about 400°F 3000°F and absorbing gaseous contaminants therefrom when contact is effected between said process gas stream and respective quench and absorbent liquids in order to provide said cooling and absorbing functions. The flow rates of the process gas stream, quench liquid,

Kiang

1980-01-01

185

Size-velocity correlations in hybrid high order moment/multi-fluid methods for polydisperse evaporating sprays: Modeling and numerical issues  

NASA Astrophysics Data System (ADS)

Kah et al. (2010) [30,33] recently developed the Eulerian multi-size moment model (EMSM) which tackles the modeling and numerical simulation of polydisperse multiphase flows. Using a high order moment method in a compact interval, they suggested to reconstruct the number density function (NDF) by entropy maximization, which leads to a unique and realizable NDF, potentially in several size intervals, thus leading to an hybrid method between Multifluid and high order. This reconstruction is used to simulate the evaporation process, by an evaluation of the flux of droplet disappearance at zero size, the fluxes of droplets between size intervals, and an accurate description of the size shift induced by evaporation Massot et al. (2010) [15]. Although this method demonstrated its potential for evaporating polydisperse flows, two issues remain to be addressed. First, the EMSM only considers one velocity for all droplets, thus decoupling size from velocity, which is too restrictive for distributions with a large size spectrum. In most applications size-conditioned dynamics have to be accounted for. Second, the possibility to have separated dynamics for each size can lead to quasi-monodisperse distributions, which corresponds to a hard limiting case for the EM algorithm. So the behavior of the algorithm needs to be investigated, in order to reproduce the entire moment space with a reasonable accuracy. The aim of this paper is thus twofold. The EM and its related algorithm are enhanced by using a more accurate integration method in order to handle NDF close to the frontier of the moment space associated with an adaptive number of parameters to reconstruct the NDF accurately and efficiently, as well as tabulated initial guess to optimize the computational time. Then, a new model called CSVM (coupled size-velocity moments model) is introduced. Size-velocity correlations are addressed either in the evaporation and drag processes, or in the convective transport. To reach this goal, a velocity reconstruction for each size is suggested, using only one additional moment per dimension, and which can be directly applied to several size intervals. Thus, this method is a direct generalization of EMSM. To handle the convective transport, a flux splitting scheme is proposed, based on the underlying kinetic description of the disperse phase. Comparing to existing approaches, a main novelty of the CSVM is that our kinetic approach ensures built-in realizability conditions, no additional corrections of the moments being needed at each time step. The full strategy is first evaluated in 0D and 1D cases, which either demonstrates the ability to reproduce both evaporation, drag force and convection with size-velocity correlations, or the possible extension to several size intervals. Finally, the method is applied on 2D cases with only one section, showing the ability of the CSVM and its related algorithms to capture the main physics of polydisperse evaporating sprays with a minimal number of moments.

Vié, Aymeric; Laurent, Frédérique; Massot, Marc

2013-03-01

186

Hot gas desulfurization sorbent and method  

SciTech Connect

A multiple metal oxide sorbent supported on a zeolite of substantially silicon oxide is used for the desulfurization of process gas streams, such as from a coal gasifier, at temperatures in the range of about 1200{degrees} to about 1600{degrees}F. The sorbent is provided by a mixture of copper oxide and manganese oxide and preferably such a mixture with molybdenum oxide. The manganese oxide and the molybdenum are believed to function as promoters for the reaction of hydrogen sulfide with copper oxide. Also, the manganese oxide inhibits the volatilization of the molybdenum oxide at the higher temperatures.

Gasper-Galvin, L.D.; Atimtay, A.T.

1991-03-13

187

Hot gas desulfurization sorbent and method  

SciTech Connect

A multiple metal oxide sorbent supported on a zeolite of substantially silicon oxide is used for the desulfurization of process gas streams, such as from a coal gasifier, at temperatures in the range of about 1200[degrees] to about 1600[degrees]F. The sorbent is provided by a mixture of copper oxide and manganese oxide and preferably such a mixture with molybdenum oxide. The manganese oxide and the molybdenum are believed to function as promoters for the reaction of hydrogen sulfide with copper oxide. Also, the manganese oxide inhibits the volatilization of the molybdenum oxide at the higher temperatures.

Gasper-Galvin, L.D.; Atimtay, A.T.

1991-03-13

188

Apparatus and method for excluding gas from a liquid  

DOEpatents

The present invention is directed to an apparatus and method for preventing diffusion of a gas under high pressure into the bulk of a liquid filling a substantially closed chamber. This apparatus and method is particularly useful in connection with test devices for testing fluid characteristics under harsh conditions of extremely high pressure and high temperature. These devices typically pressurize the liquid by placing the liquid in pressure and fluid communication with a high pressure inert gas. The apparatus and method of the present invention prevent diffusion of the pressurizing gas into the bulk of the test liquid by decreasing the chamber volume at a rate sufficient to maintain the bulk of the liquid free of absorbed or dissolved gas by expelling that portion of the liquid which is contaminated by the pressurizing gas.

Murphy, Jr., Robert J. (Bellaire, TX)

1985-01-01

189

Apparatus and method for drying gas by glycol scrubbing  

Microsoft Academic Search

An apparatus and method are described for drying a gas by passing the gas stream through an absorber where water and some hydrocarbons are removed. The absorbent and removed water and hydrocarbons are then passed to a stripping zone, where the hydrocarbons and water are removed from the absorbent. The water and hydrocarbons are separated, one from the other, after

C. E. Alleman; W. F. Tuckett

1973-01-01

190

An investigation of longwall gob gas behavior and control methods  

SciTech Connect

The National Inst. for Occupational Safety and Health (NIOSH) has initiated the use of a tracer gas in field studies to characterize geologic and mining factors influencing the migration of longwall gob gas. Three studies have been conducted using sulfur hexafluoride (SF{sub 6}) at a coal mine in the Northern Appalachian Basin operating in the Pittsburgh Coalbed. Eight underground tracer gas releases and one gob gas venthole release are summarized. The results indicate that the gas flow in the bleeder network and in the interior regions of longwall panel gobs do not strongly interact and that the negative pressure provided by gob gas venthole exhausters is very significant in maintaining this behavior. The data also show that ventilation practices employed in a large multi-panel gob area are functioning in accordance with the intent of the engineering design, a fact which would be difficult to evaluate using conventional mine ventilation measurement methods.

Schatzel, S.J.; Diamond, W.P.; Garcia, F.; LaScola, J.C.; McCall, F.E.; Jeran, P.W.; Mucho, T.P.

1999-07-01

191

Method for making hydrogen rich gas from hydrocarbon fuel  

DOEpatents

A method of forming a hydrogen rich gas from a source of hydrocarbon fuel in which the hydrocarbon fuel contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion at a temperature not less than about 400 C for a time sufficient to generate the hydrogen rich gas while maintaining CO content less than about 5 volume percent. There is also disclosed a method of forming partially oxidized hydrocarbons from ethanes in which ethane gas contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion for a time and at a temperature sufficient to form an oxide. 4 figs.

Krumpelt, M.; Ahmed, S.; Kumar, R.; Doshi, R.

1999-07-27

192

Method for making hydrogen rich gas from hydrocarbon fuel  

DOEpatents

A method of forming a hydrogen rich gas from a source of hydrocarbon fuel in which the hydrocarbon fuel contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion at a temperature not less than about 400.degree. C. for a time sufficient to generate the hydrogen rich gas while maintaining CO content less than about 5 volume percent. There is also disclosed a method of forming partially oxidized hydrocarbons from ethanes in which ethane gas contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion for a time and at a temperature sufficient to form an oxide.

Krumpelt, Michael (Naperville, IL); Ahmed, Shabbir (Bolingbrook, IL); Kumar, Romesh (Naperville, IL); Doshi, Rajiv (Downers Grove, IL)

1999-01-01

193

A steady-state non-equilibrium molecular dynamics approach for the study of evaporation processes.  

PubMed

Two non-equilibrium methods (called bubble method and splitting method, respectively) have been developed and tested to study the steady state evaporation of a droplet surrounded by its vapor, where the evaporation continuously occurs at the vapor-liquid interface while the droplet size remains constant. In the bubble method, gas molecules are continuously reinserted into a free volume (represented by a bubble) located at the centre of mass of the droplet to keep the droplet size constant. In the splitting method, a molecule close to the centre of mass of the droplet is split into two: In this way, the droplet size is also maintained during the evaporation. By additional local thermostats confined to the area of insertion, the effect of frequent insertions on properties such as density and temperature can be limited to the immediate insertion area. Perturbations are not observed in other parts of the droplet. In the end, both the bubble method and the splitting method achieve steady-state droplet evaporation. Although these methods have been developed using an isolated droplet, we anticipate that they will find a wide range of applications in the study of the evaporation of isolated films and droplets or thin films on heated substrates or under confinement. They can in principle also be used to study the steady-state of other physical processes, such as the diffusion or permeation of gas molecules or ions in a pressure gradient or a concentration gradient. PMID:24116576

Zhang, Jianguo; Müller-Plathe, Florian; Yahia-Ouahmed, Méziane; Leroy, Frédéric

2013-10-01

194

A Component Prediction Method for Flue Gas of Natural Gas Combustion Based on Nonlinear Partial Least Squares Method  

PubMed Central

Quantitative analysis for the flue gas of natural gas-fired generator is significant for energy conservation and emission reduction. The traditional partial least squares method may not deal with the nonlinear problems effectively. In the paper, a nonlinear partial least squares method with extended input based on radial basis function neural network (RBFNN) is used for components prediction of flue gas. For the proposed method, the original independent input matrix is the input of RBFNN and the outputs of hidden layer nodes of RBFNN are the extension term of the original independent input matrix. Then, the partial least squares regression is performed on the extended input matrix and the output matrix to establish the components prediction model of flue gas. A near-infrared spectral dataset of flue gas of natural gas combustion is used for estimating the effectiveness of the proposed method compared with PLS. The experiments results show that the root-mean-square errors of prediction values of the proposed method for methane, carbon monoxide, and carbon dioxide are, respectively, reduced by 4.74%, 21.76%, and 5.32% compared to those of PLS. Hence, the proposed method has higher predictive capabilities and better robustness. PMID:24772020

Cao, Hui; Yan, Xingyu; Li, Yaojiang; Wang, Yanxia; Zhou, Yan; Yang, Sanchun

2014-01-01

195

A component prediction method for flue gas of natural gas combustion based on nonlinear partial least squares method.  

PubMed

Quantitative analysis for the flue gas of natural gas-fired generator is significant for energy conservation and emission reduction. The traditional partial least squares method may not deal with the nonlinear problems effectively. In the paper, a nonlinear partial least squares method with extended input based on radial basis function neural network (RBFNN) is used for components prediction of flue gas. For the proposed method, the original independent input matrix is the input of RBFNN and the outputs of hidden layer nodes of RBFNN are the extension term of the original independent input matrix. Then, the partial least squares regression is performed on the extended input matrix and the output matrix to establish the components prediction model of flue gas. A near-infrared spectral dataset of flue gas of natural gas combustion is used for estimating the effectiveness of the proposed method compared with PLS. The experiments results show that the root-mean-square errors of prediction values of the proposed method for methane, carbon monoxide, and carbon dioxide are, respectively, reduced by 4.74%, 21.76%, and 5.32% compared to those of PLS. Hence, the proposed method has higher predictive capabilities and better robustness. PMID:24772020

Cao, Hui; Yan, Xingyu; Li, Yaojiang; Wang, Yanxia; Zhou, Yan; Yang, Sanchun

2014-01-01

196

Reservoir evaporation in central Colorado  

USGS Publications Warehouse

Evaporation losses from seven reservoirs operated by the Denver Water Department in central Colorado were determined during various periods from 1974 to 1980. The reservoirs studies were Ralston, Cheesman, Antero, Williams Fork, Elevenmile Canyon, Dillon, and Gross. Energy-budget and mass-transfer methods were used to determine evaporation. Class-A pan data also were collected at each reservoir. The energy-budget method was the most accurate of the methods used to determine evaporation. At Ralston, Cheesman, Antero, and Williams Fork Reservoirs the energy-budget method was used to calibrate the mass-transfer coefficients. Calibrated coefficients already were available for Elevenmile Canyon, Dillon, and Gross Reservoirs. Using the calibrated coefficients, long-term mass-transfer evaporation rates were determined. Annual evaporation values were not determined because the instrumentation was not operated for the entire open-water season. Class-A pan data were used to determine pan coefficients for each season at each reservoir. The coefficients varied from season to season and between reservoirs, and the seasonal values ranged from 0.29 to 1.05. (USGS)

Spahr, N. E.; Ruddy, B. C.

1983-01-01

197

Method predicts hydrates for high-pressure gas streams  

SciTech Connect

A new procedure extends the pressure range for estimating hydrate formation in high-pressure gas wells such as those now being developed in the North Sea. The method applies for uninhibited as well as methanol and ethylene glycol inhibited hydrate-forming conditions of pure components and natural gas mixtures. Accurate information concerning the conditions under which hydrates will form or exist in a natural gas stream are vital to the natural gas industry. As pressure-temperature conditions used for transporting natural gas become more severe, predicting hydrate forming conditions becomes increasingly difficult. Addition of a hydrate inhibitor, such as methanol or ethylene glycol, further complicates reliable prediction of hydrate-forming conditions. The paper describes hydrate formation, model development, and model validation.

Moshfeghian, M. (Bushier Univ. (Iran, Islamic Republic of)); Maddox, R.N. (Maddox (R.N.), Stillwater, OK (United States))

1993-08-30

198

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...

199

Gas-kinetic moving mesh methods for viscous flow simulations  

Microsoft Academic Search

In this thesis, the gas-kinetic BGK scheme for two-dimensional viscous flow computation is extended to the moving meshes. Specifically, both the static adaptive grid method and dynamic unified moving mesh method have been developed. In the former one, the grid movement and adaptation are controlled by a monitor function which depends on the gradient of flow variables, such as density

Changqiu Jin

2006-01-01

200

A Method of Concentrating Ripened Cheese Volatiles for Gas Chromatography  

Microsoft Academic Search

A method has been developed for concentrating the volatile organic compounds in ripened cheese for gas chromatographic analysis. The method consists of a rapid, room temperature churning of a cheese slurry and centrifugation of the resulting heated butter. The dry aromatic oil which is obtained is subjected to high vacuum distillation and the distillates are fractionated. With fully mature Blue

E. Scarpellino; F. V. Kosikowski

1961-01-01

201

Consider mechanical recompression evaporation  

Microsoft Academic Search

Mechanical recompression is a technique for improving latent heat management by recycling the latent heat of evaporation. The product vapor is isotropically compressed to a higher temperature and pressure so that it can be used as the heating medium that drives the evaporation. The mechanical recompression evaporator typically requires no main process steam, cooling water, or process steam condenser. The

1994-01-01

202

Direct simulation methods for compressible inviscid ideal-gas flow  

Microsoft Academic Search

Two novel schemes are proposed for the calculation of compressible flow of an ideal fluid. One method is the equilibrium analog of the well-known discrete-particle direct simulation Monte Carlo method for the treatment of nonequilibrium ideal-gas flows. The second follows from an analytical treatment of the model inertial-transport mechanisms inherent in the first scheme. Accounts of the methods are presented

D. I. Pullin

1980-01-01

203

Vapor-based interferometric measurement of local evaporation rate and interfacial temperature of evaporating droplets.  

PubMed

The local evaporation rate and interfacial temperature are two quintessential characteristics for the study of evaporating droplets. Here, it is shown how one can extract these quantities by measuring the vapor concentration field around the droplet with digital holographic interferometry. As a concrete example, an evaporating freely receding pending droplet of 3M Novec HFE-7000 is analyzed at ambient conditions. The measured vapor cloud is shown to deviate significantly from a pure-diffusion regime calculation, but it compares favorably to a new boundary-layer theory accounting for a buoyancy-induced convection in the gas and the influence upon it of a thermal Marangoni flow. By integration of the measured local evaporation rate over the interface, the global evaporation rate is obtained and validated by a side-view measurement of the droplet shape. Advective effects are found to boost the global evaporation rate by a factor of 4 as compared to the diffusion-limited theory. PMID:24506092

Dehaeck, Sam; Rednikov, Alexey; Colinet, Pierre

2014-03-01

204

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

NASA Technical Reports Server (NTRS)

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.

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

2009-01-01

205

Methods for gas detection using stationary hyperspectral imaging sensors  

DOEpatents

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.

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

2012-04-24

206

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 ...

207

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 ...

208

Thermal clearance control method for gas turbine engine  

Microsoft Academic Search

This patent describes a method for controlling blade tip to shroud clearance at a steady state, part load operating conditions in a gas turbine engine having an output power level responsive to the position of an engine power level and further having an active clearance control system delivering a scheduled flow of cooling air to an engine case supporting the

F. M. Schwarz; C. J. Jr. Crawley

1991-01-01

209

Aircraft Engine Gas Path Diagnostic Methods: Public Benchmarking Results  

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

210

Optical fiber drawing method with gas flow controlling system  

SciTech Connect

A new method for reducing the diameter variation of optical fibers during fiber drawing is proposed. This method is based on the control of gas flow and drawing speed. Faster fluctuations in diameter are suppressed by adjusting the gas flow rate, and slower ones are controlled by changing the drawing speed. The efficiency of this method has been tested by applying stepwise disturbance of +- 63 percent in preform feeding speed. Fluctuations of fiber diameter are controlled within +- 1 /mu/m despite the forced disturbance. By applying this method to high-speed drawing (300 m/min), a high tensile strength fiber, with diameter fluctuations within +- 1 /mu/m and transmission losses near the 0.85-/mu/m wavelength region of approximately 3 dB/km is achieved.

Imoto, K.; Toda, G.; Suganuma, T.; Sumi, M.

1989-01-01

211

PARTICLE-GAS DYNAMICS WITH ATHENA: METHOD AND CONVERGENCE  

SciTech Connect

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 {eta}r for dimensionless stopping time {tau} {sub 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%.

Bai Xuening; Stone, James M., E-mail: xbai@astro.princeton.ed, E-mail: jstone@astro.princeton.ed [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2010-10-15

212

Particle-gas Dynamics with Athena: Method and Convergence  

NASA Astrophysics Data System (ADS)

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%.

Bai, Xue-Ning; Stone, James M.

2010-10-01

213

Method of making gas diffusion layers for electrochemical cells  

DOEpatents

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.

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

2002-01-01

214

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

SciTech Connect

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.

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

215

Evaporation From Lake Superior  

NASA Astrophysics Data System (ADS)

Evaporation is a critical component of the water balance of each of the Laurentian Great Lakes, and understanding the magnitude and physical controls of evaporative water losses are important for several reasons. Recently, low water levels in Lakes Superior and Michigan/Huron have had socioeconomic, ecological, and even meteorological impacts (e.g. water quality and quantity, transportation, invasive species, recreation, etc.). The recent low water levels may be due to increased evaporation, but this is not known as operational evaporation estimates are currently calculated as the residual of water or heat budgets. Perhaps surprisingly, almost nothing is known about evaporation dynamics from Lake Superior and few direct measurements of evaporation have been made from any of the Laurentian Great Lakes. This research is the first to attempt to directly measure evaporation from Lake Superior by deploying eddy covariance instrumentation. Results of evaporation rates, their patterns and controlling mechanisms will be presented. The direct measurements of evaporation are used with concurrent satellite and climate model data to extrapolate evaporation measurements across the entire lake. This knowledge could improve predictions of how climate change may impact the lake's water budget and subsequently how the water in the lake is managed.

Spence, C.; Blanken, P.; Hedstrom, N.; Leshkevich, G.; Fortin, V.; Charpentier, D.; Haywood, H.

2009-05-01

216

Method for removing essential oils and antioxidants from extract products of lamiaceae species using rolled film evaporation  

US Patent & Trademark Office Database

An increase in specific antioxidant activity of extracts from rosemary (Rosemarinus officinalis) is obtained by the use of a blend of tetrafluoroethane and an organic solvent in the extraction process. A blend of tetrafluoroethane, acetone and methanol improves total yield. A tetrafluoroethane and acetone blend has higher efficacy but comparatively lower yields. The methods yield a liquid and oily antioxidant extract that is readily mixed with a liquid product such as soybean oil for addition to animal feeds and human food. The methods simultaneously yield pharmaceutical-grade essential oils in high yields.

2002-09-17

217

Determination of the calorific value of natural gas by different methods  

Microsoft Academic Search

The determination of the calorific value of natural gases is of great economic importance in gas supply. In this paper, different methods for calorific value determination are described.Besides gas calorimetry using the classical procedure of burning a gas sample, different methods are available: analytical methods which are based on the analysis of the gas sample, correlative methods which allow the

Peter Ulbig; Detlev Hoburg

2002-01-01

218

Evaporation Anisotropy of Forsterite  

NASA Astrophysics Data System (ADS)

Evaporation anisotropy of a synthetic single crystal of forsterite was investigated by high temperature vacuum experiments. The (001), (010), and (001) surfaces show microstructures characteristic for each surface. Obtained overall linear evaporation rates for the (001), (010), and (001) surfaces are ~17, ~7, and ~22 mm/hour, and the intrinsic evaporation rates, obtained by the change in surface microstructures, are ~10, ~4.5, and ~35 mm/hour, respectively. The difference between the intrinsic evaporation rates and overall rates can be regarded as contribution of dislocation, which is notable for the (100) and (010) surfaces and insignificant for the (001) surface. This is consistent with observed surface microstructures.

Ozawa, K.; Nagahara, H.; Morioka, M.

1996-03-01

219

Measurement of Irrigation Evaporative Losses by a New Vapor Budget Technique.  

National Technical Information Service (NTIS)

The importance of evaporative losses in water resources planning is discussed, and an overall review of the existing methods for estimation of evaporation is presented. A new technique for short term measurement of evaporation from moist, rough surfaces (...

P. Inmula, B. L. Sill

1985-01-01

220

The Effect of Nitrogen Gas Flow Rate on the Properties of TiN-COATED High-Speed Steel (hss) Using Cathodic Arc Evaporation Physical Vapor Deposition (pvd) Technique  

NASA Astrophysics Data System (ADS)

Cathodic arc evaporation (CAE) is a widely-used technique for generating highly ionized plasma from which hard and wear resistant physical vapor deposition (PVD) coatings can be deposited. A major drawback of this technique is the emission of micrometer-sized droplets of cathode material from the arc spot, which are commonly referred to as "macroparticles." In present study, titanium nitride (TiN) coatings on high-speed steel (HSS) coupons were produced with a cathodic arc evaporation technique. We studied and discussed the effect of various nitrogen gas flow rates on microstructural and mechanical properties of TiN-coated HSS coupons. The coating properties investigated in this work included the surface morphology, thickness of deposited coating, adhesion between the coating and substrate, coating composition, coating crystallography, hardness and surface characterization using a field emission scanning electron microscope (FE-SEM) with energy dispersive X-ray (EDX), X-ray diffraction (XRD) with glazing incidence angle (GIA) technique, scratch tester, hardness testing machine, surface roughness tester, and atomic force microscope (AFM). An increase in the nitrogen gas flow rate showed decrease in the formation of macro-droplets in CAE PVD technique. During XRD-GIA studies, it was observed that by increasing the nitrogen gas flow rate, the main peak [1,1,1] shifted toward the lower angular position. Surface roughness decreased with an increase in nitrogen gas flow rate but was higher than the uncoated polished sample. Microhardness of TiN-coated HSS coupons showed more than two times increase in hardness than the uncoated one. Scratch tester results showed good adhesion between the coating material and substrate. Considerable improvement in the properties of TiN-deposited thin films was achieved by the strict control of all operational steps.

Mubarak, Ali; Hamzah, Esah Binti; Mohd Toff, Mohd Radzi Hj.; Hashim, Abdul Hakim Bin

221

Consider mechanical recompression evaporation  

SciTech Connect

Mechanical recompression is a technique for improving latent heat management by recycling the latent heat of evaporation. The product vapor is isotropically compressed to a higher temperature and pressure so that it can be used as the heating medium that drives the evaporation. The mechanical recompression evaporator typically requires no main process steam, cooling water, or process steam condenser. The economy is in the range of what could be achieved by a 10- to 20-effect evaporator. The technique of mechanical recompression evaporation is not wet. The chemical process industries (CPI) in North American and Europe began using it extensively in the 1970s, probably as a results of the oil crisis. And, it will continue to play a major role in the removal of water for process applications. This article explains what mechanical recompression evaporation is, its advantages and disadvantages, and where it can be used. It also provides guidance on selecting the evaporator and compressor--the most important components of a mechanical recompression evaporation system.

Ward, A.

1994-04-01

222

Statistical Methods Handbook for Advanced Gas Reactor Fuel Materials  

SciTech Connect

Fuel materials such as kernels, coated particles, and compacts are being manufactured for experiments simulating service in the next generation of high temperature gas reactors. These must meet predefined acceptance specifications. Many tests are performed for quality assurance, and many of these correspond to criteria that must be met with specified confidence, based on random samples. This report describes the statistical methods to be used. The properties of the tests are discussed, including the risk of false acceptance, the risk of false rejection, and the assumption of normality. Methods for calculating sample sizes are also described.

J. J. Einerson

2005-05-01

223

Method for cleansing noxious constituents from gas streams  

SciTech Connect

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.

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

1982-05-18

224

Isotope-ratio-monitoring gas chromatography methods for high-precision isotopic analysis of nanomole  

E-print Network

Isotope-ratio-monitoring gas chromatography methods for high-precision isotopic analysis and a commercially available continuous-flow, gas chromatography interface (the Finnigan Gas Bench II). This work

Bebout, Gray E.

225

Evaporation of intercepted snow: Analysis of governing factors  

Microsoft Academic Search

Insufficient understanding of winter hydrology conditions still hampers progress in predicting springtime discharge. The least known term in the winter water balance is evaporation, particularly of intercepted snown. Recent studies have show that the evaporation from intercepted snow can be important. This paper elaborates factors governing evaporation of intercepted snow. Measurements with a cut tree-weighing device combined with a method

A. Lundberg; S. Halldin

1994-01-01

226

Self-contained cryogenic gas sampling apparatus and method  

DOEpatents

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.

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

1996-03-26

227

Self-contained cryogenic gas sampling apparatus and method  

DOEpatents

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.

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

228

Development of nondestructive evaluation methods for hot gas filters.  

SciTech Connect

Rigid ceramic hot gas candle filters are currently under development for high-temperature hot gas particulate cleanup in advanced coal-based power systems. The ceramic materials for these filters include monolithics (usually non-oxides), oxide and non-oxide fiber-reinforced composites, and recrystallized silicon carbide. A concern of end users in using these types of filters, where over 3000 may be used in a single installation, is the lack of a data base on which to base decisions for reusing, replacing or predicting remaining life during plant shutdowns. One method to improve confidence of usage is to develop nondestructive evaluation (NDE) technology to provide surveillance methods for determination of the extent of damage or 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 temperatures. Although in situ NDE methods would be desirable in order to avoid disassembly of the candle filter vessels, the possible presence of filter cakes and/or ash bridging, and the state of current NDE technology prevent this. Thus, off-line NDE methods, if demonstrated to be reliable, fast and cost effective, could be a significant step forward in developing confidence in utilization of rigid ceramic hot gas filters. Recently, NDE methods have been developed which show promise of providing information to build this confidence. Acousto-ultrasound, a totally nondestructive method, together with advanced digital signal processing, has been demonstrated to provide excellent correlation with remaining strength on new, as-produced filters, and for detecting damage in some monolithic filters when removed from service. Thermal imaging, with digital signal processing for determining through-wall thermal diffusivity, has also been demonstrated to correlate with remaining strength in both new (as-received) and in-service filters. Impact acoustic resonance using a scanning laser vibrometer has been demonstrated to allow detection of changes in frequency which may be correlated to remaining strength. These methods have been shown to be applicable to clay-bonded SiC filters, recrystallized SiC filters, CVI-SiC composite filters and oxide composite filters. Other NDE methods under development include: (a) fast, high spatial-resolution X-ray imaging for detecting density variations and dimensional changes; (b) air-coupled ultrasonic methods for determining through-thickness compositional variations; and (c) acoustic emission technology with mechanical loading for detecting localized bulk damage.

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

1999-01-01

229

Development of NDE methods for hot gas filters.  

SciTech Connect

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.

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

1999-07-21

230

Sample Analysis Results for a Benchscale Evaporator Test Using a Hanford Tank 241-AN-102 Sample  

SciTech Connect

This report provides the analytical results of samples taken during the low-activity waste evaporator process demonstration conducted at the Savannah River Technology Center with a 15-liter sample of Hanford tank 241-AN102 pretreated radioactive supernate. The objective of the task was to determine the concentration of various organic, inorganic and radionuclide constituents of potential concern and physical properties of the evaporator feed, concentrate, condensate and off gas for the Hanford River Protection Project. Over 150 samples and blanks were collected and analyzed in accordance with EPA methods. One hundred nineteen target organic analyze concentrations were shown to be less than the minimum quantitative limits in all samples (feed, concentrate, condensate, and off gas samples).Tetrahydrofuran (THF) was present in evaporator samples. THF was the most concentrated volatile compound detected in the off gas. No pesticides or polychlorinated biphenyls (PCBs) were detected in any evaporator sample. Very low levels of some dioxins and furans were reported in the off-gas samples, but are thought to have been due to contamination. Most of the sample collection, sample preparation, and sample analyses provided results with sufficient pedigree to support the rigor associated with regulatory application of these results.

Ferrara, D.M.

2003-08-25

231

Method of producing natural gas from a subterranean formation. [melting natural gas containing hydrates with electric currents  

Microsoft Academic Search

A method is given of producing gas from subterranean formations characterized by the steps of drilling and completing a plurality of at least two wells in a subterranean formation that contains at least some of the gas in the form of hydrate; melting the hydrates in the subterranean formation to free natural gas in situ; and producing to the surface

Katz

1975-01-01

232

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

233

Applications of Electromagnetic Measurement Methods in Oil and Gas Industry  

NASA Astrophysics Data System (ADS)

When hydrocarbons accumulate in reservoirs, the reservoir rocks and a large volume of rock associated with the reservoirs undergo resistance changes. This method relates generally to the field of geophysical prospecting for the purposes of hydrocarbon exploration, development, and production. This method includes measuring magnetic field gradient in at least two orthogonal directions in response to the induced electromagnetic field and determining an electric field response. Specifically, this method is a method for determining the difference between the electrical resistance of a reservoir at an initial time and its electrical resistance at one or more later times, and relating that difference to production of hydrocarbons from the reservoir during the interim period. Electromagnetic methods are now being used to provide images of subsurface resistance on the reservoir scale. These images provide for the first time observation of the distribution of porosity and fluid content on the same scale as the reservoir. They are being used to identify bypassed oil, monitor sweep efficiency, identify unanticipated breakthrough, and map features. All such information could previously only be inferred from measurements within the well or from production data from the well. For monitoring production and enhanced recovery processes, when it can be assumed that the porosity is essentially constant and when there is a resistivity contrast in the different fluids or phases involved, the imaged resistivity is a direct mapping of the changes in saturation. In this paper we discuss about the methods for electromagnetic measurement methods and its application in oil and gas industry.

Dehghani, Maryam

2011-12-01

234

Robust Design of SAW Gas Sensors by Taguchi Dynamic Method.  

PubMed

This paper adopts Taguchi's signal-to-noise ratio analysis to optimize the dynamic characteristics of a SAW gas sensor system whose output response is linearly related to the input signal. The goal of the present dynamic characteristics study is to increase the sensitivity of the measurement system while simultaneously reducing its variability. A time- and cost-efficient finite element analysis method is utilized to investigate the effects of the deposited mass upon the resonant frequency output of the SAW biosensor. The results show that the proposed methodology not only reduces the design cost but also promotes the performance of the sensors. PMID:22573961

Tsai, Hsun-Heng; Wu, Der Ho; Chiang, Ting-Lung; Chen, Hsin Hua

2009-01-01

235

Quantifying nonisothermal subsurface soil water evaporation  

NASA Astrophysics Data System (ADS)

Accurate quantification of energy and mass transfer during soil water evaporation is critical for improving understanding of the hydrologic cycle and for many environmental, agricultural, and engineering applications. Drying of soil under radiation boundary conditions results in formation of a dry surface layer (DSL), which is accompanied by a shift in the position of the latent heat sink from the surface to the subsurface. Detailed investigation of evaporative dynamics within this active near-surface zone has mostly been limited to modeling, with few measurements available to test models. Soil column studies were conducted to quantify nonisothermal subsurface evaporation profiles using a sensible heat balance (SHB) approach. Eleven-needle heat pulse probes were used to measure soil temperature and thermal property distributions at the millimeter scale in the near-surface soil. Depth-integrated SHB evaporation rates were compared with mass balance evaporation estimates under controlled laboratory conditions. The results show that the SHB method effectively measured total subsurface evaporation rates with only 0.01-0.03 mm h-1difference from mass balance estimates. The SHB approach also quantified millimeter-scale nonisothermal subsurface evaporation profiles over a drying event, which has not been previously possible. Thickness of the DSL was also examined using measured soil thermal conductivity distributions near the drying surface. Estimates of the DSL thickness were consistent with observed evaporation profile distributions from SHB. Estimated thickness of the DSL was further used to compute diffusive vapor flux. The diffusive vapor flux also closely matched both mass balance evaporation rates and subsurface evaporation rates estimated from SHB.

Deol, Pukhraj; Heitman, Josh; Amoozegar, Aziz; Ren, Tusheng; Horton, Robert

2012-11-01

236

CAPSULE REPORT: EVAPORATION PROCESS  

EPA Science Inventory

Evaporation has been an established technology in the metal finishing industry for many years. In this process, wastewaters containing reusable materials, such as copper, nickel, or chromium compounds are heated, producing a water vapor that is continuously removed and condensed....

237

Mixed feed evaporator  

DOEpatents

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.

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

1982-01-01

238

Measure Guideline: Evaporative Condensers  

SciTech Connect

The purpose of this measure guideline on evaporative condensers is to provide information on a cost-effective solution for energy and demand savings in homes with cooling loads. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices. This document has been prepared to provide a process for properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs.

German, A.; Dakin, B.; Hoeschele, M.

2012-03-01

239

Optical methods for monitoring harmful gas in animal facilities  

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

240

Large Eddy Simulation of Evaporating Kerosene Sprays  

Microsoft Academic Search

Large Eddy Simulation (LES) is applied to turbulent, kerosene sprays and the effect of turbulence and temperature fluctuations on the structure of the sprays under cold and evaporating conditions is discussed. A Lagrangian formula- tion is adopted for the particle dispersion coupled with an Eulerian description for the carrier gas. A stochastic model has been used for the representation of

W. P. Jones; S. Lyra; A. J. Marquis

241

Preparation and in vitro evaluation of propylthiouracil microspheres made of Eudragit RL 100 and cellulose acetate butyrate polymers using the emulsion-solvent evaporation method.  

PubMed

The objectives of this investigation are to evaluate the encapsulation efficiency of the anti-thyroid agent 6-n-propyl-2-thiouracil using two polymers of different characteristics (cellulose acetate butyrate polymer, (CAB-551-0.01) and ammonio methacrylate copolymer (Eudragit RL 100) and to study the effect of this encapsulation on the drug release properties. Polymers were used separately and in combination to prepare different microspheres. Also, the effect of polymer solution phase viscosity was studied for each of the polymers and for their combinations. An Ostwald viscometer was used to evaluate the relative viscosities of polymer solution phases and their combinations. Microspheres with 25% theoretical drug loading of 6-n-propyl-2-thiouracil core material were prepared by the emulsion solvent evaporation method. Microspheres prepared from CAB-551-0.01, which has higher relative polymer phase viscosity than Eudragit RL 100, showed significantly lower drug release rates and a noticeable lag time. Polymer combinations of CAB-551-0.01 and Eudragit RL 100 (1:1) showed an interesting synergistic increase in relative polymer solution viscosities at all concentrations. Unlike microspheres prepared from the two polymers separately which follow Higuchi spherical matrix release kinetics, microspheres prepared using a combination (1:1) of the two polymers showed near zero order with faster rates compared to those prepared using CAB-551-0.01 equivalent polymer concentrations. The results of this study suggest that 6-n-propyl-2-thiouracil was successfully and efficiently encapsulated and release rates of matrix microspheres are related to polymer solution phase viscosity, but when polymer combinations were used other factors such as structural effects must be considered. PMID:16019914

Obeidat, W M; Price, J C

2005-05-01

242

Effect of the dispersion of Eudragit S100 powder on the properties of cellulose acetate butyrate microspheres containing theophylline made by the emulsion-solvent evaporation method.  

PubMed

The dispersion/incorporation of Eudragit S100 powder as a filler in cellulose acetate butyrate (CAB-551-0.01) microsphere containing theophylline was investigated as a means of controlling drug release. Microspheres of CAB-551-0.01 of different polymer solution concentrations/viscosities were prepared (preparations Z(0), Z(A), Z(B) and Z(C)) and evaluated and compared to microspheres of a constant concentration of CAB-551-0.01 containing different amounts of Eudragit S100 powder as a filler (preparations X(A), X(B) and X(C)). The organic solvent acetonitrile used was capable of dissolving the matrix former CAB-551-0.01 only but not Eudragit S100 powder in the emulsion-solvent evaporation method. The CAB-551-0.01 concentration in Z(A), Z(B) and Z(C) was equal to the total polymer concentration (CAB-551-0.01 and Eudragit S100 powder) in X(A), X(B) and X(C), respectively. Scanning electron microscopy (SEM) was used to identify microspheres shape and morphology. In vitro dissolution studies were carried out on the microspheres at 37 degrees C (+/-0.5 degrees C) at two successive different pH media (1.2 +/- 0.2 for 2 h and 6.5 +/- 0.2 for 10 h). Z preparations exhibited low rates of drug release in the acidic and the slightly neutral media. On the other hand, X preparations showed an initial rapid release in the acidic medium followed by a decrease in the release rate at the early stage of dissolution in the slightly neutral pH which could be due to some relaxation and gelation of Eudragit S100 powder to form a gel network before it dissolves completely allowing the remained drug to be released. PMID:17454437

Obeidat, Wasfy M; Obaidat, Ihab M

2007-05-01

243

The study on the interdependence of spray characteristics and evaporation history of fuel spray in high temperature air crossflow  

NASA Astrophysics Data System (ADS)

A numerical calculation method is used to predict the variation of the characteristics of fuel spray moving in a high temperature air crossflow, mainly, Sauter mean diameter SMD, droplet size distribution index N of Rosin-Rammler distribution and evaporation percentage changing with downstream distance X from the nozzle. The effect of droplet heat-up period evaporation process and forced convection are taken into full account; thus, the calculation model is a very good approximation to the process of spray evaporation in a practical combustor, such as ramjet, aero-gas turbine, liquid propellant rocket, diesel and other liquid fuel-powered combustion devices. The changes of spray characteristics N, SMD and spray evaporation percentage with air velocity, pressure, temperature, fuel injection velocity, and the initial spray parameters are presented.

Zhu, J. Y.; Chin, J. S.

1986-06-01

244

Completion methods in thick, multilayered tight gas sands  

E-print Network

Tight gas sands, coal-bed methane, and gas shales are commonly called unconventional reservoirs. Tight gas sands (TGS) are often described as formations with an expected average permeability of 0.1mD or less. Gas production rates from TGS reservoirs...

Ogueri, Obinna Stavely

2009-05-15

245

Completion methods in thick, multilayered tight gas sands  

E-print Network

Tight gas sands, coal-bed methane, and gas shales are commonly called unconventional reservoirs. Tight gas sands (TGS) are often described as formations with an expected average permeability of 0.1mD or less. Gas production rates from TGS reservoirs...

Ogueri, Obinna Stavely

2008-10-10

246

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

PubMed

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

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

2014-09-01

247

Effect of various inlet air cooling methods on gas turbine performance  

Microsoft Academic Search

Turbine air inlet cooling is one of many available commercial methods to improve the efficiency of an existing gas turbine. The method has various configurations which could be utilized for almost all installed gas turbines. This paper presents a comparison between two commons and one novel inlet air cooling method using turbo-expanders to improve performance of a gas turbine located

Mahmood Farzaneh-Gord; Mahdi Deymi-Dashtebayaz

2011-01-01

248

Kinetics and thermodynamics of thin-film deposition by molecular beam methods. II. Nucleation, growth, and evaporation of cadmium on germanium single crystals  

Microsoft Academic Search

A study has been made of all stages of the deposition of thin films of cadmium on germanium single crystals with (100), (110), (111), (211), and (331) orientations. In the preceding paper, we examined adsorption phenomena in detail. This paper gives the results on the kinetics and thermodynamics of the nucleation and growth stages and of the evaporation of cadmium

R. J. H. Voorhoeve; J. N. Carides; R. S. Wagner

1972-01-01

249

Tank 26 Evaporator Feed Pump Transfer Analysis  

SciTech Connect

The transfer of liquid salt solution from Tank 26 to an evaporator is to be accomplished by activating the evaporator feed pump, located approximately 72 inches above the sludge layer, while simultaneously turning on the downcomer. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the dissolved solution transfer has been performed using computational fluid dynamics methods to determine the amount of entrained sludge solids pumped out of the tank to the evaporator with the downcomer turned on. The analysis results showed that, for the maximum and minimum supernate levels in Tank 26 (252.5 and 72 inches above the sludge layer, respectively), the evaporator feed pump will entrain between 0.03 and 0.1 wt% sludge undissolved solids weight fraction into the eductor, respectively, and therefore are an order of magnitude less than the 1.0 wt% undissolved solids loading criteria to feed the evaporator. Lower tank liquid levels, with respect to the sludge layer, result in higher amounts of sludge entrainment due to the increased velocity of the plunging jets from the downcomer and evaporator feed pump bypass as well as decreased dissipation depth. Revision 1 clarifies the analysis presented in Revision 0 and corrects a mathematical error in the calculations for Table 4.1 in Revision 0. However, the conclusions and recommendations of the analysis do not change for Revision 1.

Tamburello, David; Dimenna, Richard; Lee, Si

2009-02-11

250

A Method For Estimating Pulmonary Blood Flow With Respiratory Inert Gas Analysis In An Open Gas Circuit  

Microsoft Academic Search

A model for non-invasively estimating pul- monary blood flow by applying respiratory inert gas analysis and a measuring system based on this model are described. This method allows the measurement to be performed in an open circuit gas system avoiding physiological disturbance inherent in rebreathing methods. As well, this method can be combined with a con- ventional breath-by-breath method to

K. Gan; I. Nishi; A. S. Slutsky

1990-01-01

251

Total introduction of microsamples in inductively coupled plasma mass spectrometry by high-temperature evaporation chamber with a sheathing gas stream.  

PubMed

A systematic study on the high-temperature Torch Integrated Sample Introduction System (TISIS) for use in Inductively Coupled Plasma Mass Spectrometry (ICP-MS) has been performed. The investigation included the optimization of the relevant parameters (chamber temperature, sheathing gas flow rate, nebulizer gas flow rate, sample uptake rate), the evaluation of its performance characteristics (sensitivity, limits of detection, stability, memory effects, use with the dynamic reaction cell) and representative applications to environmental, biological and clinical samples. Under the optimal conditions (T=150°C; nebulizer gas flow rate of 0.7Lmin(-1) along with sheathing gas flow rate of 0.35Lmin(-1) and a sample uptake rate of 20?Lmin(-1)), the sensitivity was from 2 to 8 times higher than that measured using a conventional micronebulizer/mini-spray chamber system, due to the enhanced analyte mass transport toward the plasma and the solvent introduction in the vapour form. In addition, for several elements, TISIS provided lower limits of detection than the conventional system, even when the latter worked at 5-fold higher sample uptake rate. Short-term and long-term precision was better than 5%. Spectroscopic interferences arising from common matrices were efficiently removed by the dynamic reaction cell technique. The application of TISIS/ICP-MS to representative certified reference samples (spinach leaves, marine plankton, bone tissue, human blood) proved the suitability of this system for the accurate analysis of limited-size samples. PMID:23452782

Grotti, Marco; Ardini, Francisco; Todolì, Josè Luis

2013-03-12

252

VAPOR PRESSURES AND EVAPORATION COEFFICIENTS OF FE, NA AND K OVER CHONDRULE COMPOSITION MELTS. A. V. Fedkin1  

E-print Network

VAPOR PRESSURES AND EVAPORATION COEFFICIENTS OF FE, NA AND K OVER CHONDRULE COMPOSITION MELTS. A. V and isotopic evidence of significant evaporative losses from chondrules is rare. The free evaporation flux and evaporation coefficient of species x, resp., R is the gas constant and T is the temperature. Thus, computation

Grossman, Lawrence

253

Method of detecting a fault of an exhaust gas recirculation system  

Microsoft Academic Search

This patent describes a method of detecting a fault of an exhaust gas recirculation system of an internal combustion engine, wherein a temperature relating to a temperature of the exhaust gas recirculating through the exhaust gas recirculation system is detected when the exhaust gas recirculation system is in a condition in which the system should be operated to return part

T. Hashimoto; A. Takahashi; T. Imaizuma; S. Saito; H. Tanaka; T Jimbo

1989-01-01

254

Apparatus For The Liquefaaction Of Natural Gas And Methods Relating To Same  

Microsoft Academic Search

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

Bruce M. Wilding; Dennis N. Bingham; Michael G. McKellar; Terry D. Turner; Kevin T. Raterman; Gary L. Palmer; Kerry M. Klingler; John J. Vranicar

2005-01-01

255

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

Microsoft Academic Search

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

Bruce M. Wilding; Dennis N. Bingham; Michael G. McKellar; Terry D. Turner; Kevin T. Raterman; Gary L. Palmer; Kerry M. Klingler; John J. Vranicar

2007-01-01

256

Apparatus For The Liquefaaction Of Natural Gas And Methods Relating To Same  

Microsoft Academic Search

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

Bruce M. Wilding; Dennis N. Bingham; Michael G. McKellar; Terry D. Turner; Kevin T. Raterman; Gary L. Palmer; Kerry M. Klingler; John J. Vranicar

2003-01-01

257

Evaporation and Thermal Balance of Tiny HI Clouds  

E-print Network

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.

Jonathan D. Slavin

2006-10-10

258

Apparatus and method for gas turbine active combustion control system  

NASA Technical Reports Server (NTRS)

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.

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

259

Method for removing metal vapor from gas streams  

DOEpatents

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.

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

1996-01-01

260

Method for removing metal vapor from gas streams  

DOEpatents

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.

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

1996-04-02

261

Method for controlling exhaust gas heat recovery systems in vehicles  

DOEpatents

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.

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

2013-06-11

262

Lattice-Boltzmann simulations of droplet evaporation.  

PubMed

We study the utility and validity of lattice-Boltzmann (LB) simulations to explore droplet evaporation driven by a concentration gradient. Using a binary-fluid lattice-Boltzmann algorithm based on Cahn-Hilliard dynamics, we study the evaporation of planar films and 3D sessile droplets from smooth solid surfaces. Our results show that LB simulations accurately reproduce the classical regime of quasi-static dynamics. Beyond this limit, we show that the algorithm can be used to explore regimes where the evaporative and diffusive timescales are not widely separated, and to include the effect of boundaries of prescribed driving concentration. We illustrate the method by considering the evaporation of a droplet from a solid surface that is chemically patterned with hydrophilic and hydrophobic stripes. PMID:25186667

Ledesma-Aguilar, Rodrigo; Vella, Dominic; Yeomans, Julia M

2014-11-01

263

Gas-liquid separator and method of operation  

DOEpatents

A system for gas-liquid separation in electrolysis processes is provided. The system includes a first compartment having a liquid carrier including a first gas therein and a second compartment having the liquid carrier including a second gas therein. The system also includes a gas-liquid separator fluidically coupled to the first and second compartments for separating the liquid carrier from the first and second gases.

Soloveichik, Grigorii Lev (Latham, NY); Whitt, David Brandon (Albany, NY)

2009-07-14

264

Method for removing particulate matter from a gas stream  

DOEpatents

Particulate matter is removed from a stream of pressurized gas by directing the stream of gas upwardly through a bed of porous material, the porous bed being held in an open ended container and at least partially submerged in liquid. The passage of the gas through the porous bed sets up a circulation in the liquid which cleans the particulate matter from the bed.

Postma, Arlin K. (Benton City, WA)

1984-01-01

265

Hot air drum evaporator  

DOEpatents

An evaporation system for aqueous radioactive waste uses standard 30 and 55 gallon drums. Waste solutions form cascading water sprays as they pass over a number of trays arranged in a vertical stack within a drum. Hot dry air is circulated radially of the drum through the water sprays thereby removing water vapor. The system is encased in concrete to prevent exposure to radioactivity. The use of standard 30 and 55 gallon drums permits an inexpensive compact modular design that is readily disposable, thus eliminating maintenance and radiation build-up problems encountered with conventional evaporation systems.

Black, Roger L. (Idaho Falls, ID)

1981-01-01

266

Method for removing undesired particles from gas streams  

DOEpatents

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.

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

267

An analytical method for trifluoroacetic Acid in water and air samples using headspace gas chromatographic determination of the methyl ester.  

PubMed

An analytical method has been developed for the determination of trace levels of trifluoroacetic acid (TFA), an atmospheric breakdown product of several of the hydrofluorocarbon (HFC) and hydrochlorofluorocarbon (HCFC) replacements for the chlorofluorocarbon (CFC) refrigerants, in water and air. TFA is derivatized to the volatile methyl trifluoroacetate (MTFA) and determined by automated headspace gas chromatography (HSGC) with electron-capture detection or manual HSGC using GC/MS in the selected ion monitoring (SIM) mode. The method is based on the reaction of an aqueous sample containing TFA with dimethyl sulfate (DMS) in concentrated sulfuric acid in a sealed headspace vial under conditions favoring distribution of MTFA to the vapor phase. Water samples are prepared by evaporative concentration, during which TFA is retained as the anion, followed by extraction with diethyl ether of the acidified sample and then back-extraction of TFA (as the anion) in aqueous bicarbonate solution. The extraction step is required for samples with a relatively high background of other salts and organic materials. Air samples are collected in sodium bicarbonate-glycerin-coated glass denuder tubes and prepared by rinsing the denuder contents with water to form an aqueous sample for derivatization and analysis. Recoveries of TFA from spiked water, with and without evaporative concentration, and from spiked air were quantitative, with estimated detection limits of 10 ng/mL (unconcentrated) and 25 pg/mL (concentrated 250 mL:1 mL) for water and 1 ng/m(3) (72 h at 5 L/min) for air. Several environmental air, fogwater, rainwater, and surface water samples were successfully analyzed; many showed the presence of TFA. PMID:21619278

Zehavi, D; Seiber, J N

1996-10-01

268

Evaporation of extrasolar planets  

E-print Network

Atomic hydrogen escaping from the extrasolar giant planet HD209458b provides the largest observational signature ever detected for an extrasolar planet atmosphere. In fact, the upper atmosphere of this planet is evaporating. Observational evidences and interpretations coming from various models are reviewed. Implications for exoplanetology are discussed.

David Ehrenreich

2008-07-11

269

3, 12151248, 2006 Evaporation  

E-print Network

flow through the column which compensates the latent heat of evaporation. 1 Introduction Movement primarily operate in this range, including groundwater recharge and solute transport through soils phase of an experiment are10 thought to be well-understood and are attributed to the onset of the heat

Paris-Sud XI, Université de

270

TANK 32 EVAPORATOR FEED PUMP TRANSFER ANALYSIS  

SciTech Connect

The transfer of liquid salt solution from Tank 32 to an evaporator is to be accomplished by activating the evaporator feed pump, with the supernate surface at a minimum height of approximately 74.4 inches above the sludge layer, while simultaneously turning on the downcomer with a flow rate of 110 gpm. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the dissolved solution transfer has been performed using computational fluid dynamics (CFD) methods to determine the amount of entrained sludge solids pumped out of the tank toward the evaporator with the downcomer turned on. The analysis results shows that, for the minimum tank liquid level of 105 inches above the tank bottom (which corresponds to a liquid depth of 74.4 inches above the sludge layer), the evaporator feed pump will contain less than 0.1 wt% sludge solids in the discharge stream, which is an order of magnitude less than the 1.0 wt% undissolved solids (UDS) loading criteria to feed the evaporator. Lower liquid levels with respect to the sludge layer will result in higher amounts of sludge entrainment due to the increased plunging jet velocity from the downcomer disturbing the sludge layer.

Tamburello, D; Richard Dimenna, R; Si Lee, S

2009-01-27

271

TANK 26 EVAPORATOR FEED PUMP TRANSFER ANALYSIS  

SciTech Connect

The transfer of liquid salt solution from Tank 26 to an evaporator is to be accomplished by activating the evaporator feed pump, located approximately 72 inches above the sludge layer, while simultaneously turning on the downcomer. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the dissolved solution transfer has been performed using computational fluid dynamics methods to determine the amount of entrained sludge solids pumped out of the tank to the evaporator with the downcomer turned on. The analysis results showed that, for the maximum and minimum supernate levels in Tank 26 (252.5 and 72 inches above the sludge layer, respectively), the evaporator feed pump will entrain between 0.05 and 0.1 wt% sludge solids weight fraction into the eductor, respectively. Lower tank liquid levels, with respect to the sludge layer, result in higher amounts of sludge entrainment due to the increased velocity of the plunging jets from the downcomer and evaporator feed pump bypass as well as decreased dissipation depth.

Tamburello, D; Si Lee, S; Richard Dimenna, R

2008-09-30

272

Internal dynamics of evaporating droplets  

SciTech Connect

The full Navier-Stokes equations and the energy equation are solved for the fluid inside and outside of a droplet using a front tracking/finite difference method. The boundaries of the domain are taken periodic in the horizontal direction and wall bounded in the vertical direction. The behavior of a two-dimensional deformable liquid drop in zero gravity is studied and the dynamics of the flow is analyzed. The effects of governing nondimensional parameters on the evaporation rate are also discussed.

Esmaeeli, A.; Arpaci, V. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Mechanical Engineering and Applied Mechanics; Chai, A.T. [NASA Lewis Research Center, Cleveland, OH (United States)

1996-12-31

273

A numerical method for gas–solid two-phase free turbulent flow using a vortex method  

Microsoft Academic Search

This paper presents a numerical method for gas–solid two-phase free turbulent flow. The computation of the gas flow by a vortex method and the Lagrangian calculation of the particle motion are simultaneously performed, in which the change in the vorticity for the gas-phase by the interaction between the two phases is taken into account. The change due to the force

Tomomi Uchiyama; Masaaki Naruse

2001-01-01

274

Development of NDE methods for hot gas filters  

Microsoft Academic Search

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

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

1999-01-01

275

Methods For Delivering Liquified Gas To An Engine  

DOEpatents

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.

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

276

Systems and method for delivering liquified gas to an engine  

DOEpatents

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.

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

277

Method for high temperature mercury capture from gas streams  

DOEpatents

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.

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

2006-04-25

278

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

Microsoft Academic Search

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,

A. S. Choi; D. C. Iverson

1996-01-01

279

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

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

Wada, Takao; Ueda, Noriaki

2013-01-01

280

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

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

Wada, Takao; Ueda, Noriaki

2013-04-21

281

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

DOEpatents

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.

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

282

Role of buffer gas pressure on the synthesis of carbon nanotubes by arc discharge method  

NASA Astrophysics Data System (ADS)

Few-walled carbon nanotubes (CNTs) were synthesized by the arc discharge process. The study pertains to analyze the effect of buffer gas pressure (Helium) and density of graphite anodes on morphology and yield of CNTs. The synthesis of CNTs was carried out at different buffer pressures of Helium ranging from 80 Torr to 600 Torr using different anode densities specifically 1.6 and 1.8 gm/cc. FE-SEM and TGA studies indicated that the highest percentage of MWCNTs was formed around 450 Torr pressure as compared to other pressures. It was observed that the variation of gas pressure affects the current drawn capacity and also the evaporation rate of the graphite electrode. Micro-structure of CNTs synthesized at 450 Torr consists of 8 concentric graphene layers. Improved crystallinity with better thermal stability was observed in case of high density graphite anode.

Kota, Manikantan; Padya, Balaji; Ramana, G. Venkata; Jain, P. K.; Padmanabham, G.

2013-06-01

283

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...

284

Gas concentration detection with FBGs and compensation method  

NASA Astrophysics Data System (ADS)

A novel scheme of gas concentration detection based on a frequency modulation technique is introduced in this paper, which resolves the problems of centric wavelength drift and variations of modulation amplitude by using an ASE source, FBG and a specific mechanical vibration device. A wavelength Scanning optical source for gas detection can be easily achieved.

Zhong, Chunlan; Dong, Xiaopeng; Li, Junjun; Qi, Jie; Li, Sensen; Li, Weiwen

2008-12-01

285

Segmented inlet nozzle for gas turbine, and methods of installation  

Microsoft Academic Search

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

Klompas

1985-01-01

286

Putting the "vap" into evaporation  

NASA Astrophysics Data System (ADS)

In the spirit of the Special Issue of HESS to which it contributes, this paper documents the origin and development of the science of natural evaporation from land surfaces over the last 30-35 years, since the symposium A View from the Watershed was held to commemorate the opening of the new Institute of Hydrology (IH) building in 1973. Important subsequent technical progress includes the ability to measure routinely the diurnal cycle of near-surface meteorological variables using automatic weather stations, and of surface energy and momentum exchanges using automated implementations of the Bowen Ratio/Energy Budget technique and the Eddy Correlation technique, along with the capability to estimate the "fetch" for which these measurements apply. These improvements have been complemented by new methods to measure the separate components of evaporation, including: the interception process using randomly relocated below-canopy gauges, transpiration fluxes from individual leaves/shoots using porometers and from plants/plant components using stem-flow gauges and soil evaporation using micro-lysimeters and soil moisture depletion methods. In recent years progress has been made in making theory-based area-average estimates of evaporation using scintillometers, and model-based area-average estimates by assembling many streams of relevant data into Land Data Assimilation Systems. Theoretical progress has been made in extending near-surface turbulence theory to accommodate the effect of the "excess" boundary layer resistance to leaf-to-air transfer of energy and mass fluxes relative to that for momentum, and to allow for observed shortcoming in stability factors in the transition layer immediately above vegetation. Controversy regarding the relative merits of multi-layer model and "big leaf" representations of whole-canopy exchanges has been resolved in favour of the latter approach. Important gaps in the theory of canopy-atmosphere interactions have been filled, including recognising the need, separately, to represent dry-canopy and wet-canopy evaporation in models and the capability to describe wet-to-dry canopy transitions as well as the ability to describe sparse vegetation canopies which only partly cover the underlying soil. There is progress in methods of estimating crop water requirements, but an important recommendation of this paper is that this progress should continue by introducing use of an effective stomatal resistance rather than crop factors. The paper draws attention to relevant theoretical insight on this issue. Progress in theoretical understanding of evaporation processes has been used in the creation of numerous Land Surface Parameterisations (LSPs), the models used to represent land-surface interaction in climate and weather forecast models, and there have been important advances in describing the behaviour of plant stomata in LSPs. A major investment over the last 25 years in conducting Large-Scale Field Experiments, the better to measure, understand and model coupled land-surface/atmosphere interactions, has resulted in improvements in the capabilities of global climate models and the ability of mesoscale meteorological models to describe the enhanced circulation resulting from different forms of land-surface heterogeneity. Progress in understanding why early equations for potential evapotranspiration can be adequate in certain conditions is reviewed. The paper concludes with recommendations for future research.

Shuttleworth, W. J.

2007-01-01

287

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

PubMed

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

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

2014-08-19

288

Evaporative production of bright atomic solitons.  

PubMed

We describe a method of producing bright atomic solitons of 7Li through efficient radio frequency evaporation in a combined magnetic and optical trap. Solitons released in a magnetic waveguide propagate without dispersion, with lifetimes limited by two-body dipolar relaxation. We show how the method can be used to deterministically produce pairs of solitons. PMID:24580683

Medley, P; Minar, M A; Cizek, N C; Berryrieser, D; Kasevich, M A

2014-02-14

289

Evaporative Production of Bright Atomic Solitons  

NASA Astrophysics Data System (ADS)

We describe a method of producing bright atomic solitons of Li7 through efficient radio frequency evaporation in a combined magnetic and optical trap. Solitons released in a magnetic waveguide propagate without dispersion, with lifetimes limited by two-body dipolar relaxation. We show how the method can be used to deterministically produce pairs of solitons.

Medley, P.; Minar, M. A.; Cizek, N. C.; Berryrieser, D.; Kasevich, M. A.

2014-02-01

290

A Simpler Way to Tame Multiple-Effect Evaporators.  

ERIC Educational Resources Information Center

Presents a new method to teach the subject of evaporators which is both simple enough to use in the classroom and accurate and flexible enough to be used as a design tool in practice. Gives an example using a triple evaporator series. Analyzes the effect of this method. (CW)

Joye, Donald D.; Koko, F. William Jr.

1988-01-01

291

Based on the probability estimation of gas coal-dust explosion risk evaluation method  

Microsoft Academic Search

Because the present safety evaluation could not exactly make the quantitative conclusions, this paper analyzes the reasons why the present evaluation methods are difficult to make the quantitative conclusions and provides the probability estimation method of the gas and coal dust explosion risk. Using this method determines the gas and coal dust explosion risk and gets the quantitative results of

Jianhua Sun; Shang Xie; Chunrong Wei; Jingpeng Zhang; Yi Zhao

2011-01-01

292

Abstract--In this paper, Reversed-Flow Gas Chromatography (RF-GC) is utilized to investigate the  

E-print Network

Abstract--In this paper, Reversed-Flow Gas Chromatography (RF-GC) is utilized to investigate Chromatography (RF-GC) method can be used as an indicator to `measure' the evaporation rates of liquid Manuscript by a factor of 46-50% [16-22]. This paper demonstrates the utilization of RF-GC in the study of evaporation

Paris-Sud XI, Université de

293

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

SciTech Connect

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.

Mendelsohn, Marshall H.; Huang, Hann-Sheng

1997-12-01

294

A new tracer gas method to measure oxygen transfer and enhancement factor on RBC  

Microsoft Academic Search

The aim of this study was to test a new application of tracer gas in rotating biological contactors (RBC). Our method using propane as tracer gas, is able to quantify the purely physical gas liquid exchange. The procedure was utilized on RBC in order to measure: (a) the physical transfer coefficient with clean discs (Kla) in tap water and in

B.-E. Boumansour; J.-L. Vasel

1998-01-01

295

Method for the removal of elemental mercury from a gas stream  

DOEpatents

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.

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

1999-01-01

296

Method for the removal of elemental mercury from a gas stream  

DOEpatents

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. 7 figs.

Mendelsohn, M.H.; Huang, H.S.

1999-05-04

297

A quadrature-based moment method for gas-particle flows  

E-print Network

A quadrature-based moment method for gas-particle flows Alberto Passalacqua, Rodney O. Fox - College Park Alberto Passalacqua (Iowa State University) QMOM for polydisperse gas-particle flows Annual-laden channel flow Alberto Passalacqua (Iowa State University) QMOM for polydisperse gas-particle flows Annual

Maryland at College Park, University of

298

Improving Model-Based Gas Turbine Fault Diagnosis Using Multi-Operating Point Method  

Microsoft Academic Search

A comprehensive gas turbine fault diagnosis system has been designed using a full nonlinear simulator developed in Turbotec company for the V94.2 industrial gas turbine manufactured by Siemens AG. The methods used for detection and isolation of faulty components are gas path analysis (GPA) and extended Kalman filter (EKF). In this paper, the main health parameter degradations namely efficiency and

Amin Salar; SeyedMehrdad Hosseini; Ali Khaki Sedigh; Behnam Rezaei Zangmolk

2010-01-01

299

Method of cooling gas only nozzle fuel tip  

DOEpatents

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.

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

2002-01-01

300

Simulations of Evaporating Multicomponent Fuel Drops  

NASA Technical Reports Server (NTRS)

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.

Bellan, Josette; Le Clercq, Patrick

2005-01-01

301

Preliminary Investigation of Tracer Gas Reaeration Method for Shallow Bays  

E-print Network

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...

Baker, Sarah H.; Holley, Edward R.

302

Method and apparatus for processing exhaust gas with corona discharge  

DOEpatents

The present invention is placing a catalyst coating upon surfaces surrounding a volume containing corona discharge. In addition, the electrodes are coated with a robust dielectric material. Further, the electrodes are arranged so that at least a surface portion of each electrode extends into a flow path of the exhaust gas to be treated and there is only exhaust gas in the volume between each pair of electrodes. 12 figs.

Barlow, S.E.; Orlando, T.M.; Tonkyn, R.G.

1999-06-22

303

Method and apparatus for processing exhaust gas with corona discharge  

DOEpatents

The present invention is placing a catalyst coating upon surfaces surrounding a volume containing corona discharge. In addition, the electrodes are coated with a robust dielectric material. Further, the electrodes are arranged so that at least a surface portion of each electrode extends into a flow path of the exhaust gas to be treated and there is only exhaust gas in the volume between each pair of electrodes.

Barlow, Stephan E. (Richland, WA); Orlando, Thomas M. (Kennewick, WA); Tonkyn, Russell G. (Kennewick, WA)

1999-01-01

304

Unconventional methods in exploration for petroleum and natural gas IV  

SciTech Connect

This book presents the papers given at a symposium on geophysical and geochemical surveys for petroleum and natural gas deposits. Topics considered at the symposium included seismic surveys, electrical techniques in mapping hydrocarbons, hydrocarbon leakage, magnetoelectic exploration, the measurement of rock magnetic susceptibility of drill cuttings, vitrinite reflectance, remote detection, soil concentrations, carbonate prospecting, and the near-surface hydrocarbon gas measurement of vertical migration.

Davidson, M.J.

1986-01-01

305

Evaporation control research, 1955-58  

USGS Publications Warehouse

One hundred fifty-two compounds and compositions of matter were screened as potential evaporation retardants. The homologous straight-chain fatty alkanols are considered the best materials for retardants. Several methods of application of the alkanols to the reservoir surface were investigated. Although wick-type drippers for the application of liquids and cage rafts for the application of solids appear to be the most promising methods from an economic standpoint, both methods have serious disadvantages. Considerable study was given to reducing biochemical oxidation of the evaporation retardants. Copper in several forms was found adequate as a bacteriostatic agent but posed a potential hazard because of its toxicity. Many other bactericides that were tested were also toxic. Two sets of large-scale field tests have been completed and several others are still in progress. On the larger reservoirs, the reduction of evaporation was not more than 20 percent under the prevailing conditions and the application procedure used. Three major practical problems remain; namely, the effects and action of wind on the monofilm, the effects of biochemical oxidation, and the most effective method of application. Fundamental problems remaining include the effects of various impurities, and the composition of the best evaporation retardant; the long-range effects of monofilms on the limnology of a reservoir, including the transfer of oxygen and carbon dioxide; toxicological aspects of all components of any evaporation-retardant composition, plus toxicology of any composition chosen for large-scale use; and further studies of the calorimetry and thermodynamics involved in the mechanism of evaporation and its reduction by a monofilm.

Cruse, Robert R.; Harbeck, Guy Earl.

1960-01-01

306

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

SciTech Connect

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

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

1996-05-02

307

Integration of Gas Chromatography Mass Spectrometry Methods for Differentiating Ricin Preparation Methods  

SciTech Connect

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 the castor plant Ricinus communis. 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 chromatographic - mass spectrometric (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 and 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.

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

2012-05-17

308

Tried and True: Evaporating is cool  

NSDL National Science Digital Library

Many students hold misconceptions about evaporation. In this short exercise, students will apply the kinetic molecular theory to explain how cold water can evaporate and to observe the cooling effect of evaporation, and develop their own evaporation experiments.

Hand, Richard

2006-03-01

309

Normal evaporation of binary alloys  

NASA Technical Reports Server (NTRS)

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.

Li, C. H.

1972-01-01

310

Catastrophic evaporation of rocky planets  

NASA Astrophysics Data System (ADS)

Short-period exoplanets can have dayside surface temperatures surpassing 2000 K, hot enough to vaporize rock and drive a thermal wind. Small enough planets evaporate completely. We construct a radiative hydrodynamic model of atmospheric escape from strongly irradiated, low-mass rocky planets, accounting for dust-gas energy exchange in the wind. Rocky planets with masses ? 0.1 M? (less than twice the mass of Mercury) and surface temperatures ?2000 K are found to disintegrate entirely in ?10 Gyr. When our model is applied to Kepler planet candidate KIC 12557548b - which is believed to be a rocky body evaporating at a rate of dot{M} gtrsim 0.1 M_{{{oplus }}} Gyr-1 - our model yields a present-day planet mass of ? 0.02 M? or less than about twice the mass of the Moon. Mass-loss rates depend so strongly on planet mass that bodies can reside on close-in orbits for Gyr with initial masses comparable to or less than that of Mercury, before entering a final short-lived phase of catastrophic mass-loss (which KIC 12557548b has entered). Because this catastrophic stage lasts only up to a few per cent of the planet's life, we estimate that for every object like KIC 12557548b, there should be 10-100 close-in quiescent progenitors with sub-day periods whose hard-surface transits may be detectable by Kepler - if the progenitors are as large as their maximal, Mercury-like sizes (alternatively, the progenitors could be smaller and more numerous). According to our calculations, KIC 12557548b may have lost ˜70 per cent of its formation mass; today we may be observing its naked iron core.

Perez-Becker, Daniel; Chiang, Eugene

2013-08-01

311

Semiconductor gas sensors based on nanostructured tungsten oxide  

Microsoft Academic Search

Semiconductor gas sensors based on nanocrystallline WO3 films were produced by two different methods. Advanced reactive gas evaporation was used in both cases either for a direct deposition of films (deposited films) or to produce ultra fine WO3 powder which was used for screen printing of thick films. The deposited films sintered at 480 °C and the screen-printed films sintered

J. L Solis; S Saukko; L Kish; C. G Granqvist; V Lantto

2001-01-01

312

EVAPORATION OF ICY PLANETESIMALS DUE TO BOW SHOCKS  

SciTech Connect

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.

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

313

Radiative feedback and cosmic molecular gas: numerical method  

E-print Network

We present results from self-consistent 3D numerical simulations of cosmic structure formation with a multi-frequency radiative transfer scheme and non-equilibrium molecular chemistry of 13 primordial species (e-, H, H+, H-, He, He+, He++, H2, H2+, D, D+, HD, HeH+), performed by using the simulation code GADGET. We describe our implementation and show tests for ionized sphere expansion in a static and dynamic density field around a central radiative source, and for cosmological abundance evolution coupled with the cosmic microwave background radiation. As a demonstrative application of radiative feedback on molecular gas, we run also cosmological simulations of early structure formation in a ~1Mpc size box. Our tests agree well with analytical and numerical expectations. Consistently with other works, we find that ionization fronts from central sources can boost H2 fractions in shock-compressed gas. The tight dependence on H2 lead to a corresponding boost of HD fractions, as well. We see a strong lowering of the the typical molecular abundances up to several orders of magnitudes which partially hinders further gas collapse of pristine neutral gas, and clearly suggests the need of re-ionized gas or metal cooling for the formation of the following generation of structures.

Margarita Petkova; Umberto Maio

2011-10-03

314

NUTRITIONAL EVALUATION OF VARIOUS FEEDSTUFFS FOR LIVESTOCK PRODUCTION USING IN VITRO GAS METHOD  

Microsoft Academic Search

A study was undertaken to evaluate the nutritional quality of some conventional and non-conventional feed resources by using in vitro gas method. Samples of various feedstuffs were analyzed chemically, as well as by in vitro gas method. The feedstuffs having different digestibilities showed significant (P<0.05) differences in the rate and amount of gas production, metabolizable energy (ME) and digestibility of

S. A. KHANUM; T. YAQOOB; S. SADAF; M. HUSSAIN; M. A. JABBAR; H. N. HUSSAIN; R. KAUSAR; S. REHMAN

315

Evaporative cooling of the dipolar hydroxyl radical.  

PubMed

Atomic physics was revolutionized by the development of forced evaporative cooling, which led directly to the observation of Bose-Einstein condensation, quantum-degenerate Fermi gases and ultracold optical lattice simulations of condensed-matter phenomena. More recently, substantial progress has been made in the production of cold molecular gases. Their permanent electric dipole moment is expected to generate systems with varied and controllable phases, dynamics and chemistry. However, although advances have been made in both direct cooling and cold-association techniques, evaporative cooling has not been achieved so far. This is due to unfavourable ratios of elastic to inelastic scattering and impractically slow thermalization rates in the available trapped species. Here we report the observation of microwave-forced evaporative cooling of neutral hydroxyl (OH(•)) molecules loaded from a Stark-decelerated beam into an extremely high-gradient magnetic quadrupole trap. We demonstrate cooling by at least one order of magnitude in temperature, and a corresponding increase in phase-space density by three orders of magnitude, limited only by the low-temperature sensitivity of our spectroscopic thermometry technique. With evaporative cooling and a sufficiently large initial population, much colder temperatures are possible; even a quantum-degenerate gas of this dipolar radical (or anything else it can sympathetically cool) may be within reach. PMID:23257881

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

2012-12-20

316

Defrosting method adopting dual hot gas bypass for an air-to-air heat pump  

Microsoft Academic Search

A novel dual hot gas bypass defrosting (DHBD) method is developed to remove frost from the outside heat exchanger (HEX) of an air-to-air heat pump. The proposed method adopts two bypass lines of hot gas from the compressor: one is connected to the inlet of the outdoor HEX, and the other is connected to the outlet of the exchanger. We

Hwan-Jong Choi; Byung-Soon Kim; Donghoon Kang; Kyung Chun Kim

2011-01-01

317

Collocation method for the modeling of membrane gas permeation systems A. Feichtingera  

E-print Network

Collocation method for the modeling of membrane gas permeation systems A. Feichtingera , A In this work, we describe a numerical method which enables an efficient computation of membrane gas permeation. This is a crucial feature when combining computation of membrane permeation processes with optimization algorithms

Weinmüller, Ewa B.

318

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

DOEpatents

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.

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

2006-10-10

319

Diffusion NMR methods applied to xenon gas for materials study.  

PubMed

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

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

2002-12-01

320

Diffusion NMR methods applied to xenon gas for materials study  

NASA Technical Reports Server (NTRS)

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. c2002 John Wiley & Sons, Ltd.

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

2002-01-01

321

Characterization of uncertainties in atmospheric trace gas inversions using hierarchical Bayesian methods  

E-print Network

We present a hierarchical Bayesian method for atmospheric trace gas inversions. This method is used to estimate emissions of trace gases as well as "hyper-parameters" that characterize the probability density functions ...

Rigby, M.

322

Evaporatively controlled growth of salt trees  

NASA Astrophysics Data System (ADS)

During the latter stages of the evaporation of ammonium chloride solutions, highly ramified salt structures, centimeters in height, are formed. In contrast with many, if not all, of the commonly discussed branched solidified object (e.g., dendrites or diffusion-limited aggregation clusters), the porous nature of the salt trees leads to growth in a direction away from the material source owing to a coupling between capillarity and evaporation. A physical mechanism for the phenomenon is reported, growth as a function of external convection is studied and demonstrates growth directed opposite the convective flow, and a method for determining a fractal dimension of the three-dimensional trees is described.

Du, Rose; Stone, H. A.

1996-02-01

323

Some Photoelectric Properties of Evaporated Bismuth Films  

Microsoft Academic Search

Some photoelectric properties of bismuth films deposited on glass by evaporation in high vacuum are investigated. It is shown that the photoelectric emission and threshold wave-length increase with film thickness to a limiting value. DuBridge's method, in which the photoelectric currents are measured at a single incident frequency and variable temperature, was employed in the threshold determinations and an excellent

Alfred H. Weber

1938-01-01

324

Waste tank ventilation rates measured with a tracer gas method  

Microsoft Academic Search

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

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

1998-01-01

325

Volumetric radial basis function methods applied to gas dynamics  

Microsoft Academic Search

A set of rotational and translation transformations are applied to the Euler gas dynamic equations. In such a transformed coordinate frame, the partial differential equations (PDEs) appear as a set of steady ordinary differential equations (ODEs) in the rotating, translating frame. By using appropriate linear combinations of the ODEs, we obtain a transformed set of ODEs that resemble the compatibility

Edward J. Kansa

2003-01-01

326

Gas turbine nozzle vane insert and methods of installation  

Microsoft Academic Search

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

William John Miller; Daniel Ross Predmore; James Michael Placko

2002-01-01

327

Modelling gas hydrate thermodynamic behaviour: theoretical basis and computational methods  

Microsoft Academic Search

The thermodynamic theory of van der Waals and Platteeuw has served up to now and for many decades as the principal basis for the development of tools for predicting the equilibrium conditions of various gas hydrate systems. Several of these developments are briefly presented in the present paper, with the aim of revealing associated difficulties and possible inherent limitations. After

Dimitrios Avlonitis; Nikos Varotsis

1996-01-01

328

Method of scrubbing acid gases from gas mixtures  

SciTech Connect

A process for scrubbing acid gases, especially carbon dioxide, from gas mixtures with an aqueous amine solution serving as the scrubbing liquid in which hexamethylene diamine serves as the amine. The concentration of the hexamethylene diamine in the aqueous solution is 5 to 40% by weight, preferably 25 to 35% by weight.

Beran, F.; Gerhards, H.J.; Kohler, P.; Lassmann, E.

1981-07-21

329

[Concentration calibration method of ambient trace-gas monitoring with tunable diode laser absorption spectroscopy].  

PubMed

Tunable diode laser absorption spectroscopy (TDLAS) is a new method to detect trace-gas qualitatively or quantificationally based on the scan characteristic of the diode laser used to obtain the absorption spectroscopy in the characteristic absorption region It needs to be combined with a long absorption path in the ambient trace-gas measurements. TDLAS is a new trace gas detective method developed with the combination of a tunable diode laser source and a long absorption path; it has significant advantages not only in the sensitivity but also in rapidity of response. It has been widely used in many atmospheric trace-gases detection, ground trace-gas detection and, gas leakage detection. On-line calibrating is necessary to most trace gas monitor, and in the present paper the authors introduced a simple and accurate method, analyzed it in the theory, and proved it's feasibility in the experiment. PMID:16830737

Kan, Rui-feng; Liu, Wen-qing; Zhang, Yu-jun; Liu, Jian-guo; Wang, Min; Gao, Shan-hu; Chen, Jun

2006-03-01

330

Evaporation rates of droplet arrays in turbulent reacting flows  

Microsoft Academic Search

Studies of regularly ordered droplet arrays facilitate the analysis of local effects on evaporation rates. This work investigates, using Direct Numerical Simulations (DNS), the effects of droplet density and flow conditions on evaporation of kerosene droplets in inert and reactive convective environments. A novel model, coupling a mass conservative Level Set approach with the Ghost Fluid method, is used. The

M. R. G. Zoby; S. Navarro-Martinez; A. Kronenburg; A. J. Marquis

2011-01-01

331

PRODUCTION ENGINEERING AND MARKETING ANALYSIS OF THE ROTATING DISK EVAPORATOR  

EPA Science Inventory

Recent EPA-funded research into the onsite, mechanical evaporation of wastewater from single family homes revealed that a rotating disk evaporator (RDE) could function in a nondischarging mode. Such a device has potential use where site limitations preclude conventional methods o...

332

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

PubMed

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

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

2013-12-23

333

EVAPORATION AND THE ISOTOPIC COMPOSITION OF TYPE A AND B REFRACTORY INCLUSIONS. D.S. Ebel, L. Grossman1, S.B. Simon, A. Davis1  

E-print Network

EVAPORATION AND THE ISOTOPIC COMPOSITION OF TYPE A AND B REFRACTORY INCLUSIONS. D.S. Ebel, LO2 (CMAS) liquids undergoing open system evaporation into pure H2 gas. This evaporation model is used . Finally, it is apparent that evaporated metal atoms cannot leave their oxygen behind in the liquid, so

Grossman, Lawrence

334

Experimental validation of a gas turbine cycle model based on a simultaneous solution method  

SciTech Connect

This paper presents the second phase of a work intended to set up a methodology for the performance analysis of gas turbine internal components starting from a limited amount of design and field test data. In the work phase presented here, the developed gas turbine mathematical model and the solution method have been calibrated and validated by means of design data and measurements carried out on a 5 MW industrial gas turbine. The results obtained using the simultaneous solution method demonstrate the validity of developed computer code as an aid in the diagnosis of gas turbine operating condition.

Benvenuti, E. [Nuovo Pignone S.p.A., Florence (Italy); Bettocchi, R.; Cantore, G.; Negri di Montenegro, G.; Spina, P.R. [Univ. di Bologna (Italy). Istituto di Macchine

1994-12-31

335

Representative shuttle evaporative heat sink  

NASA Technical Reports Server (NTRS)

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.

Hixon, C. W.

1978-01-01

336

Optimization of evaporative fluid coolers  

Microsoft Academic Search

In the paper the optimization of geometrical and operating parameters for evaporative fluid coolers has been presented. The algorithm of optimizational calculations contains:•the mathematical model of heat and mass transfer in evaporative fluid coolers;•model of operating costs based, among others, on the Zalewski–Gryglaszewski relations developed by the authors for evaluation of air pressure drops in the heat exchanger;•model of evaporative

Wojciech Zalewski; Beata Niezgoda-?elasko; Marek Litwin

2000-01-01

337

Synthesis and electrochemical properties of Sb2Se3 nanowires prepared by a gas induced reduction method.  

PubMed

Sb2Se3 nanowires have been prepared by a novel gas induced reduction (GIR) method. The precursor solution prepared by dissolving Sb2(OCH2CH2O)3 and SeO2 in a certain solvent was initially separated from the reductant, hydrazine hydrate. The reductant evaporated during the heating process, dissolved into the precursor solution and reacted with Sb3+ and SeO2 and finally Sb2Se3 nanostructures formed. Different solvents including diethanolamine, glycerol, ethylene glycol, deionized water, absolute ethanol and isopropyl alcohol were respectively used for comparison. It was found that when ethylene glycol was used as a solvent, pure, relatively homogeneous, and high aspect-ratio Sb2Se3 nanowires (40-120 nm in diameter and -100 microm in length) were prepared. Growth mechanism of the Sb2Se3 nanowires was proposed. The electrochemistry character of the nanowires was investigated via assembling into lithium ion batteries. The discharge capacity of Sb2Se3/Li cell cycled between 0.3 and 2.5 V was performed in the range of 142-1036 mA x h x g(-1) during the first 30 cycles, with the charge/discharge efficiency increasing from 89.4% to 97.5%. PMID:23646581

Wang, Xin; Cai, Kefeng; Chen, Song

2013-02-01

338

Benchmarking Gas Path Diagnostic Methods: A Public Approach  

NASA Technical Reports Server (NTRS)

Recent technology reviews have identified the need for objective assessments of engine health management (EHM) technology. The need is two-fold: technology developers require relevant data and problems to design and validate new algorithms and techniques while engine system integrators and operators need practical tools to direct development and then evaluate the effectiveness of proposed solutions. This paper presents a publicly available gas path diagnostic benchmark problem that has been developed by the Propulsion and Power Systems Panel of The Technical Cooperation Program (TTCP) to help address these needs. The problem is coded in MATLAB (The MathWorks, Inc.) and coupled with a non-linear turbofan engine simulation to produce "snap-shot" measurements, with relevant noise levels, as if collected from a fleet of engines over their lifetime of use. Each engine within the fleet will experience unique operating and deterioration profiles, and may encounter randomly occurring relevant gas path faults including sensor, actuator and component faults. The challenge to the EHM community is to develop gas path diagnostic algorithms to reliably perform fault detection and isolation. An example solution to the benchmark problem is provided along with associated evaluation metrics. A plan is presented to disseminate this benchmark problem to the engine health management technical community and invite technology solutions.

Simon, Donald L.; Bird, Jeff; Davison, Craig; Volponi, Al; Iverson, R. Eugene

2008-01-01

339

Method of generating hydrogen gas from sodium borohydride  

DOEpatents

A compact solid source of hydrogen gas, where the gas is generated by contacting water with micro-disperse particles of sodium borohydride in the presence of a catalyst, such as cobalt or ruthenium. The micro-disperse particles can have a substantially uniform diameter of 1-10 microns, and preferably about 3-5 microns. Ruthenium or cobalt catalytic nanoparticles can be incorporated in the micro-disperse particles of sodium borohydride, which allows a rapid and complete reaction to occur without the problems associated with caking and scaling of the surface by the reactant product sodium metaborate. A closed loop water management system can be used to recycle wastewater from a PEM fuel cell to supply water for reacting with the micro-disperse particles of sodium borohydride in a compact hydrogen gas generator. Capillary forces can wick water from a water reservoir into a packed bed of micro-disperse fuel particles, eliminating the need for using an active pump.

Kravitz, Stanley H. (Placitas, NM); Hecht, Andrew M. (Sandia Park, NM); Sylwester, Alan P. (Albuquerque, NM); Bell, Nelson S. (Albuquerque, NM)

2007-12-11

340

Glyoxal Oligomer Formation in Evaporating Cloud Droplets  

NASA Astrophysics Data System (ADS)

Glyoxal and methyl glyoxal are produced in high yields during the atmospheric oxidation of aromatic compounds, and in lower yields from isoprene and terpene oxidation. Glyoxal and methyl glyoxal are known to partition efficiently into tropospheric water droplets, reaching average concentrations of 2 - 100 and 0.3 - 60 micromolar, respectively, depending on the location. Even at such low concentrations, new particle chamber data demonstrates that the glyoxal in glyoxal/water solutions forms oligomers rather than transferring to the gas phase when the droplet evaporates. Results for methyl glyoxal will also be presented. Since cloud droplet lifetimes (~30 min) are shorter than the lifetime of glyoxal with respect to aqueous-phase oxidation by hydroxyl radicals (~ few hours), oligomerization of glyoxal during cloud droplet evaporation should be a significant source of organic aerosol, especially in urban areas where glyoxal concentrations are highest and morning fog is common.

Hanley, S. W.; Corrigan, A. L.; de Haan, D. O.

2006-12-01

341

Thermoelectric integrated membrane evaporation water recovery technology  

NASA Technical Reports Server (NTRS)

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.

Roebelen, G. J., Jr.; Winkler, H. E.; Dehner, G. F.

1982-01-01

342

Reactively evaporated films of copper molybdenum sulfide  

NASA Technical Reports Server (NTRS)

Films of superconducting Chevrel-phase copper molybdenum sulfide CuxMo6S8 were deposited on sapphire substrates by reactive evaporation using H2S as the reacting gas. Two superconducting temperatures (10.0 K and 5.0 K) of the films were found, corresponding to two different phases with different copper concentrations. All films were superconducting above 4.2 K and contained Chevrel-phase compound as well as free molybdenum. The critical current was measured as a function of applied field. One sample was found to deviate from the scaling law found for co-evaporated or sputtered samples, which possibly indicates a different pinning mechanism or inhomogeneity of the sample.

Chi, K. C.; Dillon, R. O.; Bunshah, R. F.; Alterovitz, S.; Woollam, J. A.

1978-01-01

343

Development of a direct evaporation bismuth Hall thruster  

NASA Astrophysics Data System (ADS)

Hall thrusters have been under active development around the world since the 1960's. Thrusters using traditional propellants such as xenon have been flown on a variety of satellite orbit raising and maintenance missions with an excellent record. To expand the mission envelope, it is necessary to lower the specific impulse of the thrusters but xenon and krypton are poor performers at specific impulses below 1,200 seconds. To enhance low specific impulse performance, this dissertation examines the development of a Hall-effect thruster which uses bismuth as a propellant. Bismuth, the heaviest non-radioactive element, holds many advantages over noble gas propellants from an energetics as well as a practical economic standpoint. Low ionization energy, large electron-impact cross-section and high atomic mass make bismuth ideal for low-specific impulse applications. The primary disadvantage lies in the high temperatures which are required to generate the bismuth vapors. Previous efforts carried out in the Soviet Union relied upon the complete bismuth vaporization and gas phase delivery to the anode. While this proved successful, the power required to vaporize and maintain gas phase throughout the mass flow system quickly removed many of the efficiency gains expected from using bismuth. To solve these problems, a unique method of delivering liquid bismuth to the anode has been developed. Bismuth is contained within a hollow anode reservoir that is capped by a porous metallic disc. By utilizing the inherent waste heat generated in a Hall thruster, liquid bismuth is evaporated and the vapors pass through the porous disc into the discharge chamber. Due to the high temperatures and material compatibility requirements, the anode was fabricated out of pure molybdenum. The porous vaporizer was not available commercially so a method of creating a refractory porous plate with 40-50% open porosity was developed. Molybdenum also does not respond well to most forms of welding so a diffusion bonding process was also developed to join the molybdenum porous disc to the molybdenum anode. Operation of the direct evaporation bismuth Hall thruster revealed interesting phenomenon. By utilizing constant current mode on a discharge power supply, the discharge voltage settles out to a stable operating point which is a function of discharge current, anode face area and average pore size on the vaporizer. Oscillations with a 40 second period were also observed. Preliminary performance data suggests that the direct evaporation bismuth Hall thruster performs similar to xenon and krypton Hall thrusters. Plume interrogation with a Retarding Potential Analyzer confirmed that bismuth ions were being efficiently accelerated while Faraday probe data gave a view of the ion density in the exhausted plume.

Massey, Dean Richard

344

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

DOEpatents

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.

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

345

Apparatus and method to control process to replace natural gas with fuel oil in a natural gas burner  

Microsoft Academic Search

A method whereby fuel oil is mixed with a gaseous diluent and partially vaporized, liquids separated out, superheated and burned in a natural gas burner without major modification to the burner is disclosed. The control system is: (1) a liquid level controller sensing the liquid level in the separator to automatically control the flow of the fuel oil to the

W. W. Hoehing; J. M. Jackson; E. R. Johnson

1979-01-01

346

Piecewise parabolic method (PPM) for gas-dynamical simulations  

Microsoft Academic Search

We present the piecewise parabolic method, a higher-order extension of of Godunov's method. There are several new features of this method which distinguish it from other higher-order Godunov-type methods. We use a higher-order spatial interpolation than previously used, which allows for a steeper representation of discontinuities, particularly contact discontinuities. We introduce a simpler and more robust algorithm for calculating the

P. Corlella; PAUL R. WOODWARD

1984-01-01

347

Turkish Undergraduates' Misconceptions of Evaporation, Evaporation Rate, and Vapour Pressure  

ERIC Educational Resources Information Center

This study focused on students' misconceptions related to evaporation, evaporation rate, and vapour pressure. Open-ended diagnostic questions were used with 107 undergraduates in the Primary Science Teacher Training Department in a state university in Turkey. In addition, 14 students from that sample were interviewed to clarify their written…

Canpolat, Nurtac

2006-01-01

348

Evaporation regimes and evaporation modelling in an alpine tundra environment  

Microsoft Academic Search

Evaporation rates responded very quickly to surface desiccation, and the control by surface resistance (derived from the Penman-Monteith model) was very pronounced. The absence of an efficient means to transfer subsurface moisture to the surface resulted in an evaporation regime which was strongly moisture-limited only a few days after precipitation. However, the high frequency of precipitation events in this environment

I. R. Saunders; W. G. Bailey; J. D. Bowers

1997-01-01

349

Method for removal of mercury from various gas streams  

DOEpatents

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.

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

2003-06-10

350

Method for the recovery of clean pyrolysis off-gas and a rotary recycling means therefor  

Microsoft Academic Search

A method and apparatus for stripping entrained organic vapor and solid particulate matter from a pyrolytic off-gas stream is disclosed. The off-gas is introduced at the top of a conical chamber having a variable speed ''squirrel cage'' rotor at its top. The wet, dirty, off-gas is drawn into the rotor from below and impinged upon the chamber walls which causes

L. W. Elston; D. R. Hurst

1981-01-01

351

An improved chromatographic method to measure nitrogen, oxygen, argon and methane in gas or liquid samples  

Microsoft Academic Search

An improved gas chromatographic method for measuring dinitrogen (N2), oxygen (O2), argon (Ar) and methane (CH4) in gas or liquid samples has been developed. By employing a zeolite, calcium chabazite, as column packing material, optimum separation of O2 and Ar was achieved at 303 K with a carrier gas flow rate of 33.5 ml min?1. Dinitrogen and CH4 were eluted

Soonmo An; Samantha B. Joye

1997-01-01

352

17Oexcess in evaporated desert waters and vapor from evaporation experiments  

NASA Astrophysics Data System (ADS)

Oxygen and hydrogen isotopes are classical proxies for the investigation of climatic effects in hydrological processes. The combination of the isotopic ratios 17O/16O and 18O/16O in water allowed the determination of mass dependent processes and enabled differentiation between equilibrium and kinetic fractionation (Barkan and Luz, 2007). In analogy to d-excess, deviation in ?17O from the global average trend of meteoric water is defined as: 17Oexcess = ?'17O - 0.528 × ?'18O 17Oexcess depends on the impact of diffusive evaporation into air and thus reflects relative humidity conditions. The isotope ratios of water ?17O and ?18O were determined by isotope ratio gas mass spectrometry in dual inlet mode on a ThermoFinnigan MAT 253. The oxygen was extracted by water fluorination with CoF3. Our average measurement precision for ?17O is ×0.03 ‰, for ?18O ×0.05 ‰ and for 17Oexcess approximately ×7 per meg (1?). We compared 17Oexcess in natural waters from the highly arid deserts of Sistan (East Iran) and Atacama (Chile) with data obtained from evaporation experiments. In these experiments, water was evaporated into a stream of dry nitrogen and vapor collected cryogenically. The data show a systematic depletion of 17Oexcess in water with increasing degree of evaporation in the residual water body. Most negative 17Oexcess were determined for samples from ponds (Sistan) and salars (Atacama). These strongly evaporated samples indicate an evaporation development, following a fractionation trend (?) of approximately 0.523. The evaporation experiment shows a ? of 0.525 and is in agreement with water data from an experiment by Barkan and Luz (2007). The difference between natural and experimental evaporation suggests either different evaporation kinetics in the natural environment, variable proportion of kinetic and equilibrium fractionation, or additional diffusive processes during ground water seepage. References: Barkan, E. and Luz, L. (2007). Diffusivity fractionations of H216O/H217O and H216O/H218O in air and their implications for isotope hydrology. Rapid Commun. Mass Spectrom., Vol. 21, pp. 2999-3005.

Surma, J.; Assonov, S.; Staubwasser, M.

2013-12-01

353

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

DOEpatents

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.

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

2011-01-04

354

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

SciTech Connect

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.

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

1993-12-01

355

Fusion, mechanical joining methods pros, cons--Part 2. [Natural gas pipelines use of mechanical and fusion joints  

Microsoft Academic Search

Two basic techniques accepted by gas distribution utility companies for joining polyethylene pipe underground are fusion methods and mechanical joining. Washington Gas Light Co., uses the fusion methods for the most part and uses mechanical joints for repair and final tie-ins where fusion methods are impractical or impossible to use. Fusion methods used by gas industry users of plastic pipe

Gunther

1993-01-01

356

Development and application of a method for analysis of phthalates in ham sausages by solid-phase extraction and gas chromatography-mass spectrometry.  

PubMed

A gas chromatography-mass spectrometry assay was developed and successfully applied for the determination of phthalates in ham sausage migrated from packaging film. The phthalates studied were dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), benzylbutyl phthalate (BBP), bis(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DNOP), with dibutyl adipate (DBA) as internal standard. The sample pre-treatments included extraction with n-hexane, solvent evaporation and reconstitution with acetonitrile before and after solid-phase extraction (SPE). The extraction and cleaning up procedure was carried out with cartridges containing dimethyl butylamine groups, which showed extraction efficiencies over 87.3%. The calibration curves obtained were linear with correlation coefficients greater than 0.99. The method proved to be accurate and precise for the six phthalates used. It was successfully applied to a study on the migration of phthalates from packaging PVC film into ham sausage. PMID:20374814

Guo, Zhiyong; Wang, Sui; Wei, Danyi; Wang, Meili; Zhang, Huina; Gai, Panpan; Duan, Jing

2010-03-01

357

Flash evaporation of liquid monomer particle mixture  

DOEpatents

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.

Affinito, John D. (Kennewick, WA); Darab, John G. (Richland, WA); Gross, Mark E. (Pasco, WA)

1999-01-01

358

Flash evaporation of liquid monomer particle mixture  

DOEpatents

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.

Affinito, J.D.; Darab, J.G.; Gross, M.E.

1999-05-11

359

Apparatus and method for thermally stripping volatile organic compounds from soil using a recirculating combustible gas  

Microsoft Academic Search

A method is described for removing volatile organic compounds from sod, comprising the steps of: (a) loading said soil into an opening in a drum; (b) transporting said soil into said drum by rotating said drum in a first direction; (c) flowing a hot gas through said drum; (d) mechanically causing said hot gas to come into contact with said

R. A. Crosby; J. L. Crosby

1993-01-01

360

Determination of energy consumption for gas purification by the steam-condensation method  

Microsoft Academic Search

Energy consumption for gas purification by the steam-condensation method is discussed. Experiments were conducted in an experimental assembly to confirm mathematical equations and to estimate the influences of the steam-condensation effect in gas purification. Comparison of the experimental and calculated values shows that the relationships given can be used for determination of changes of the heating capacity of steam entering

G. G. Khaidarov; V. P. Isakov; V. N. Sokolov

1983-01-01

361

Thermal analysis of evaporative coolers  

Microsoft Academic Search

In order to develop the conceptual design of the Thermal Control System (TCS) of HOPE (Japanese orbiting plane planned to be launched by H2 rocket), the thermal model of the evaporative cooling system of the U.S. Space Shuttle was analyzed. This consists of Flash Evaporator Subsystem (FES) at high altitude and Ammonia Boiler Subsystem (ABS) at low altitude, both of

Masatoshi Ohuchi; Masao Furukawa; Koichi Oshima

1991-01-01

362

Evaporation-driven assembly as a route to photonic materials  

NASA Astrophysics Data System (ADS)

The unique, structure-dependent diffraction properties of photonic crystals have inspired their proposed use in applications ranging from chemosensors, to solar power applications, to optical computing devices. The range of proposed applications for photonic crystals demands a range of techniques for fabricating them, meeting differently weighted priorities including perfection, refractive index contrast, operating wavelength, throughput, and economy. This thesis contributes to the art of preparing photonic crystals by colloidal self-assembly at an evaporating solvent-air interface, a promising approach for preparing thin films of photonic material over large areas at low cost, if some defects are permissible. The simplest possible example of evaporation-driven self-assembly, the evaporation of a stagnant colloidal suspension, is demonstrated as a practical method for colloidal crystallization; although the colloidal crystal is formed at a water-air interface, and so is difficult to handle, it can be made robust for study and use by immobilization in a hydrogel. Vertical deposition is a widely used evaporation-based method for preparing thin, dry colloidal crystal films. The thickness profiles of vertically deposited colloidal crystals are measured through the Fabry-Perot fringes in their infrared reflectance spectra: the linear shape of these thickness profiles constrains proposed mechanisms for colloidal self-assembly in vertical deposition. Optimized conditions for vertical deposition are found under which colloidal crystals of 80% peak reflectance, an exceptional optical performance for a polystyrene colloid crystal on glass, are reproducibly prepared. A process is demonstrated for preparing germanium-containing, high-index-contrast photonic crystals from a polystyrene colloidal crystal template and pre-formed germanium nanoparticles, using only room-temperature processing steps; the result is an inverse opal of air macropores in a germanium-in-photoadhesive composite with refractive index 2.05. Previously published germanium infiltration techniques rely on gas-phase chemical reactions and require temperatures well above Tg for most linear polymers. As a complementary approach to this problem, some progress has also been made towards a polymer colloidal crystal template that can withstand gasphase chemistry at temperatures up to and possibly beyond 250°C, based on highly crosslinked divinylbenzene microspheres.

Shimmin, Robert G.

363

Synthesis of long YBCO, BSCCO HTSC coatings by gas-detonation spraying technology and gas-flame method of crystallization  

SciTech Connect

This technology allows for the production of long HTSC coatings for the manufacture of tapes and wires as well as shields and antennas. Gas-thermal methods allow the authors to obtain films (10 -100 {mu}m) on non-oriented substrates of arbitrary shape. A gas-flame method of crystallization allows them to obtain dense coatings with high adhesion. These HTSC composites are easily workable to shape into the desired geometry. The critical temperature of the coatings corresponds to that of the starting HTSC ceramics; T{sub c} = 82 K for YBCO and T{sub c} = 81 K, T{sub c} = 103 K for BSCCO. Values of j{sub c} =2*10{sup 3} A/cm{sup 2} at T = 77 K, H = 0 have been obtained. The proposed method has high productivity and low cost.

Bykov, Y. [Univ. of Toledo, OH (United States); Grigor`eva, A.V.; Shkut, V.A.

1997-06-01

364

Monte Carlo methods: Application to hydrogen gas and hard spheres  

Microsoft Academic Search

Quantum Monte Carlo (QMC) methods are among the most accurate for computing ground state properties of quantum systems. The two major types of QMC we use are Variational Monte Carlo (VMC), which evaluates integrals arising from the variational principle, and Diffusion Monte Carlo (DMC), which stochastically projects to the ground state from a trial wave function. These methods are applied

Mark Douglas Dewing

2001-01-01

365

Method of fabricating an abradable gas path seal  

NASA Technical Reports Server (NTRS)

The thermal shock resistance of a ceramic layer is improved. The invention is particularly directed to an improved abradable lining that is deposited on shroud forming a gas path in turbomachinery. Improved thermal shock resistance of a shroud is effected through the deliberate introduction of benign cracks. These are microcracks which will not propagate appreciably upon exposure to the thermal shock environment in which a turbine seal must function. Laser surface fusion treatment is used to introduce these microcracks. The ceramic surface is laser scanned to form a continuous dense layer. As this layer cools and solidifies, shrinkage results in the formation of a very fine crack network. The presence of this deliberately introduced fine crack network precludes the formation of a catastrophic crack during thermal shock exposure.

Bill, R. C.; Wisander, D. W. (inventors)

1984-01-01

366

Comparison study on qualitative and quantitative risk assessment methods for urban natural gas pipeline network.  

PubMed

In this paper, a qualitative and a quantitative risk assessment methods for urban natural gas pipeline network are proposed. The qualitative method is comprised of an index system, which includes a causation index, an inherent risk index, a consequence index and their corresponding weights. The quantitative method consists of a probability assessment, a consequences analysis and a risk evaluation. The outcome of the qualitative method is a qualitative risk value, and for quantitative method the outcomes are individual risk and social risk. In comparison with previous research, the qualitative method proposed in this paper is particularly suitable for urban natural gas pipeline network, and the quantitative method takes different consequences of accidents into consideration, such as toxic gas diffusion, jet flame, fire ball combustion and UVCE. Two sample urban natural gas pipeline networks are used to demonstrate these two methods. It is indicated that both of the two methods can be applied to practical application, and the choice of the methods depends on the actual basic data of the gas pipelines and the precision requirements of risk assessment. PMID:21402442

Han, Z Y; Weng, W G

2011-05-15

367

Method for converting hydrocarbon fuel into hydrogen gas and carbon dioxide  

DOEpatents

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.

Clawson, Lawrence G. (Dover, MA); Mitchell, William L. (Belmont, MA); Bentley, Jeffrey M. (Westford, MA); Thijssen, Johannes H. J. (Cambridge, MA)

2000-01-01

368

Long term measurement of lake evaporation using a pontoon mounted Eddy Covariance system  

NASA Astrophysics Data System (ADS)

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.

McGowan, H. A.; McGloin, R.; McJannet, D.; Burn, S.

2011-12-01

369

Black Hole - Never Forms, or Never Evaporates  

E-print Network

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.

Sun Yi

2011-02-13

370

Black hole — never forms, or never evaporates  

SciTech Connect

Many discussion about the black hole conundrums, such like 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 Vachaspati, 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 are clarified.

Sun, Yi, E-mail: fantadox@gmail.com [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)

2011-01-01

371

A versatile method for preparation of hydrated microbial-latex biocatalytic coatings for gas absorption and gas evolution.  

PubMed

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

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

372

Modeling of Bulk Evaporation and Condensation  

NASA Technical Reports Server (NTRS)

This report describes the modeling and mathematical formulation of the bulk evaporation and condensation involved in liquid-vapor phase change processes. An internal energy formulation, for these phase change processes that occur under the constraint of constant volume, was studied. Compared to the enthalpy formulation, the internal energy formulation has a more concise and compact form. The velocity and time scales of the interface movement were obtained through scaling analysis and verified by performing detailed numerical experiments. The convection effect induced by the density change was analyzed and found to be negligible compared to the conduction effect. Two iterative methods for updating the value of the vapor phase fraction, the energy based (E-based) and temperature based (T-based) methods, were investigated. Numerical experiments revealed that for the evaporation and condensation problems the E-based method is superior to the T-based method in terms of computational efficiency. The internal energy formulation and the E-based method were used to compute the bulk evaporation and condensation processes under different conditions. The evolution of the phase change processes was investigated. This work provided a basis for the modeling of thermal performance of multi-phase nuclear fuel elements under variable gravity conditions, in which the buoyancy convection due to gravity effects and internal heating are involved.

Anghaie, S.; Ding, Z.

1996-01-01

373

Methods of Gas Phase Capture of Iodine from Fuel Reprocessing Off-Gas: A Literature Survey  

SciTech Connect

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.

Daryl Haefner

2007-02-01

374

Evaporation of tiny water aggregation on solid surfaces of different wetting properties  

E-print Network

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.

Shen Wang; Yusong Tu; Rongzheng Wan; Haiping Fang

2012-03-08

375

Development of liquid and gas chromatographic methods for the determination of water.  

National Technical Information Service (NTIS)

Two liquid chromatographic (LC) methods and one gas chromatographic (GC) method for the determination of water are developed. In the LC methods, water in various analytical samples is separated from the sample matrices on either a single cation-exchange c...

J. Chen

1991-01-01

376

Production of methane gas from Japanese cedar chips pretreated by various delignification methods  

Microsoft Academic Search

Methane fermentation of woody waste was carried out using various pretreatment methods for delignification in order to evaluate the efficient pretreatment method for producing methane gas from woody waste. Japanese cedar (Cryptomeria japonica) chips were used as sample of woody waste. As pretreatment methods, refiner treatment, steaming treatment, steaming treatment followed by refiner treatment, basidiomycete fungi treatment, and steam explosion

Harumi Take; Yoshifumi Andou; Yoshitoshi Nakamura; Fumihisa Kobayashi; Yasuji Kurimoto; Masaaki Kuwahara

2006-01-01

377

CHEMISTRY IN EVAPORATING ICES-UNEXPLORED TERRITORY  

SciTech Connect

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.

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

378

Correcting Microwave Precipitation Retrievals for near-Surface Evaporation  

E-print Network

This paper compares two methods for correcting passive or active microwave surface precipitation estimates based on hydrometeors sensed aloft that may evaporate before landing. These corrections were derived using two years ...

Surussavadee, Chinnawat

379

Evaporative Roof Cooling- A Simple Solution to Cut Cooling Costs  

E-print Network

Since the “Energy Crisis” Evaporative Roof Cooling Systems have gained increased acceptance as a cost effective method to reduce the high cost of air conditioning. Documented case histories in retro-fit installations show direct energy savings...

Abernethy, D.

380

Evaporative Roof Cooling - A Simple Solution to Cut Cooling Costs  

E-print Network

Since the "Energy Crisis" Evaporative Roof Cooling Systems have gained increased acceptance as a cost effective method to reduce the high cost of air conditioning. Documented case histories in retrofit installations show direct energy savings...

Abernethy, D.

1985-01-01

381

Direct observation of blocked nanoscale surface evaporation on SiO2 nanodroplets  

NASA Astrophysics Data System (ADS)

Nano-scale surface evaporation of SiO2 nanodroplets from a volcano-shaped tip (tip diameter d ˜ 20 nm to 70 nm) was observed directly using an in situ transmission electron microscopy method. Au nanoparticles, those precipitated in the SiO2 matrix after an Au catalyzed growth, diffused and pinned onto the evaporation surface, which induced blocked evaporation dynamics. Our observations provide direct evidences of blocked evaporation dynamics caused by small-sized nanoparticles at the nanometer scale.

Wan, Neng; Xu, Jun; Sun, Li-Tao; Martini, Matteo; Huang, Qing-An; Hu, Xiao-Hui; Xu, Tao; Bi, Heng-Chang; Sun, Jun

2012-10-01

382

OPERATING PLAN TAILINGS CELLS AND EVAPORATION PONDS  

E-print Network

OPERATING PLAN TAILINGS CELLS AND EVAPORATION PONDS PIÃ?ON RIDGE MILL Energy Fuels Resources ..........................................................................................4 3.0 EVAPORATION POND DESIGN....................................................................14 5.0 EVAPORATION PONDS OPERATING AND MONITORING PROCEDURES ....17 5.1 Standard Operating Procedures

383

Control method for turbocharged diesel engines having exhaust gas recirculation  

Microsoft Academic Search

A method of controlling the airflow into a compression ignition engine having an EGR and a VGT. The control strategy includes the steps of generating desired EGR and VGT turbine mass flow rates as a function of the desired and measured compressor mass airflow values and exhaust manifold pressure values. The desired compressor mass airflow and exhaust manifold pressure values

Ilya V. Kolmanovsky; Mrdjan J Jankovic; Miroslava Jankovic

2000-01-01

384

Method and ducting system for hot gas heat recovery  

Microsoft Academic Search

A method and ducting system for collection of hot exhaust gases from paint curing oven heaters is disclosed for heat energy recovery in which a large collector duct is extended above the paint curing oven and into which is drawn large volumes of slightly warmed air heated by radiation from the paint curing oven or from secondary warm air sources.

1981-01-01

385

Histogrammatic Method for Determining Relative Abundance of Input Gas Pulse  

NASA Technical Reports Server (NTRS)

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.

Mandrake, Lukas; Bornstein, Benjamin J.; Madzunkov, Stojan; MacAskill, John A.

2012-01-01

386

Evaporative cooling of flare plasma  

NASA Technical Reports Server (NTRS)

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.

Antiochos, S. K.; Sturrock, P. A.

1976-01-01

387

Control of black hole evaporation?  

E-print Network

Contradiction between Hawking's semi-classical arguments and string theory on the evaporation of black hole has been one of the most intriguing problems in fundamental physics. A final-state boundary condition inside the black hole was proposed by Horowitz and Maldacena to resolve this contradiction. We point out that original Hawking effect can be also regarded as a separate boundary condition at the event horizon for this scenario. Here, we found that the change of Hawking boundary condition may affect the information transfer from the initial collapsing matter to the outgoing Hawking radiation during evaporation process and as a result the evaporation process itself, significantly.

Doyeol Ahn

2006-04-26

388

Multileg Heat-Pipe Evaporator  

NASA Technical Reports Server (NTRS)

Parallel pipes provide high heat flow from small heat exchanger. Six parallel heat pipes extract heat from overlying heat exchanger, forming evaporator. Vapor channel in pipe contains wick that extends into screen tube in liquid channel. Rods in each channel hold wick and screen tube in place. Evaporator compact rather than extended and more compatible with existing heat-exchanger geometries. Prototype six-pipe evaporator only 0.3 m wide and 0.71 m long. With ammonia as working fluid, transports heat to finned condenser at rate of 1,200 W.

Alario, J. P.; Haslett, R. A.

1986-01-01

389

Experimental Investigation of Evaporation Behavior of Polonium and Rare-Earth Elements in Lead-Bismuth Eutectic Pool  

SciTech Connect

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)

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

390

Linear nozzle with tailored gas plumes and method  

SciTech Connect

There is claimed a method for depositing fluid material from a linear nozzle in a substantially uniform manner across and along a surface. The method includes directing gaseous medium through said nozzle to provide a gaseous stream at the nozzle exit that entrains fluid material supplied to the nozzle, said gaseous stream being provided with a velocity profile across the nozzle width that compensates for the gaseous medium's tendency to assume an axisymmetric configuration after leaving the nozzle and before reaching the surface. There is also claimed a nozzle divided into respective side-by-side zones, or preferably chambers, through which a gaseous stream can be delivered in various velocity profiles across the width of said nozzle to compensate for the tendency of this gaseous medium to assume an axisymmetric configuration.

Leon, D.D.; Kozarek, R.L.; Mansour, A.; Chigier, N.

1999-10-19

391

Linear nozzle with tailored gas plumes and method  

DOEpatents

There is claimed a method for depositing fluid material from a linear nozzle in a substantially uniform manner across and along a surface. The method includes directing gaseous medium through said nozzle to provide a gaseous stream at the nozzle exit that entrains fluid material supplied to the nozzle, said gaseous stream being provided with a velocity profile across the nozzle width that compensates for the gaseous medium's tendency to assume an axisymmetric configuration after leaving the nozzle and before reaching the surface. There is also claimed a nozzle divided into respective side-by-side zones, or preferably chambers, through which a gaseous stream can be delivered in various velocity profiles across the width of said nozzle to compensate for the tendency of this gaseous medium to assume an axisymmetric configuration.

Leon, David D. (Murrysville, PA); Kozarek, Robert L. (Apollo, PA); Mansour, Adel (Mentor, OH); Chigier, Norman (Pittsburgh, PA)

1999-01-01

392

Sensitivity of Spacebased Microwave Radiometer Observations to Ocean Surface Evaporation  

NASA Technical Reports Server (NTRS)

Ocean surface evaporation and the latent heat it carries are the major components of the hydrologic and thermal forcing on the global oceans. However, there is practically no direct in situ measurements. Evaporation estimated from bulk parameterization methods depends on the quality and distribution of volunteer-ship reports which are far less than satisfactory. The only way to monitor evaporation with sufficient temporal and spatial resolutions to study global environment changes is by spaceborne sensors. The estimation of seasonal-to-interannual variation of ocean evaporation, using spacebased measurements of wind speed, sea surface temperature (SST), and integrated water vapor, through bulk parameterization method,s was achieved with reasonable success over most of the global ocean, in the past decade. Because all the three geophysical parameters can be retrieved from the radiance at the frequencies measured by the Scanning Multichannel Microwave Radiometer (SMMR) on Nimbus-7, the feasibility of retrieving evaporation directly from the measured radiance was suggested and demonstrated using coincident brightness temperatures observed by SMMR and latent heat flux computed from ship data, in the monthly time scale. However, the operational microwave radiometers that followed SMMR, the Special Sensor Microwave/Imager (SSM/I), lack the low frequency channels which are sensitive to SST. This low frequency channels are again included in the microwave imager (TMI) of the recently launched Tropical Rain Measuring Mission (TRMM). The radiance at the frequencies observed by both TMI and SSM/I were simulated through an atmospheric radiative transfer model using ocean surface parameters and atmospheric temperature and humidity profiles produced by the reanalysis of the European Center for Medium Range Weather Forecast (ECMWF). From the same ECMWF data set, coincident evaporation is computed using a surface layer turbulent transfer model. The sensitivity of the radiance to evaporation over various seasons and geographic locations are examined. The microwave frequencies with radiance that are significant correlated with evaporation are identify and capability of estimating evaporation directly from TMI will be discussed.

Liu, Timothy W.; Li, Li

2000-01-01

393

Apparatus and method of using a fuel gas regulator for a coke oven battery  

SciTech Connect

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.

Dickerson, D.M.; Filkes, R.W.

1985-08-06

394

Explosive evaporation in solar flares  

NASA Technical Reports Server (NTRS)

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.

Fisher, George H.

1987-01-01

395

A method to estimate weight and dimensions of large and small gas turbine engines  

NASA Technical Reports Server (NTRS)

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.

Onat, E.; Klees, G. W.

1979-01-01

396

Advancing New 3D Seismic Interpretation Methods for Exploration and Development of Fractured Tight Gas Reservoirs  

SciTech Connect

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.

James Reeves

2005-01-31

397

Spectroscopic method to measure the superfluid fraction of an ultracold atomic gas  

SciTech Connect

We perform detailed analytical and numerical studies of a recently proposed method for a spectroscopic measurement of the superfluid fraction of an ultracold atomic gas [N. R. Cooper and Z. Hadzibabic, Phys. Rev. Lett. 104, 030401 (2010)]. Previous theoretical work is extended by explicitly including the effects of nonzero temperature and interactions, and assessing the quantitative accuracy of the proposed measurement for a one-component Bose gas. We show that for suitably chosen experimental parameters the method yields an experimentally detectable signal and a sufficiently accurate measurement. This is illustrated by explicitly considering two key examples: First, for a weakly interacting three-dimensional Bose gas it reproduces the expected result that below the critical temperature the superfluid fraction closely follows the condensate fraction. Second, it allows a clear quantitative differentiation of the superfluid and the condensate density in a strongly interacting Bose gas.

John, S. T.; Hadzibabic, Z.; Cooper, N. R. [Cavendish Laboratory, University of Cambridge, J. J. Thomson Ave. Cambridge CB3 0HE (United Kingdom)

2011-02-15

398

Seed/catalyst-free growth of zinc oxide nanostructures on multilayer graphene by thermal evaporation  

PubMed Central

We report the seed/catalyst-free growth of ZnO on multilayer graphene by thermal evaporation of Zn in the presence of O2 gas. The effects of substrate temperatures were studied. The changes of morphologies were very significant where the grown ZnO structures show three different structures, i.e., nanoclusters, nanorods, and thin films at 600°C, 800°C, and 1,000°C, respectively. High-density vertically aligned ZnO nanorods comparable to other methods were obtained. A growth mechanism was proposed based on the obtained results. The ZnO/graphene hybrid structure provides several potential applications in electronics and optoelectronics. PMID:24533793

2014-01-01

399

Seed/catalyst-free growth of zinc oxide nanostructures on multilayer graphene by thermal evaporation  

NASA Astrophysics Data System (ADS)

We report the seed/catalyst-free growth of ZnO on multilayer graphene by thermal evaporation of Zn in the presence of O2 gas. The effects of substrate temperatures were studied. The changes of morphologies were very significant where the grown ZnO structures show three different structures, i.e., nanoclusters, nanorods, and thin films at 600°C, 800°C, and 1,000°C, respectively. High-density vertically aligned ZnO nanorods comparable to other methods were obtained. A growth mechanism was proposed based on the obtained results. The ZnO/graphene hybrid structure provides several potential applications in electronics and optoelectronics.

Ahmad, Nurul Fariha; Rusli, Nurul Izni; Mahmood, Mohamad Rusop; Yasui, Kanji; Hashim, Abdul Manaf

2014-02-01

400

Seed/catalyst-free growth of zinc oxide nanostructures on multilayer graphene by thermal evaporation.  

PubMed

We report the seed/catalyst-free growth of ZnO on multilayer graphene by thermal evaporation of Zn in the presence of O2 gas. The effects of substrate temperatures were studied. The changes of morphologies were very significant where the grown ZnO structures show three different structures, i.e., nanoclusters, nanorods, and thin films at 600°C, 800°C, and 1,000°C, respectively. High-density vertically aligned ZnO nanorods comparable to other methods were obtained. A growth mechanism was proposed based on the obtained results. The ZnO/graphene hybrid structure provides several potential applications in electronics and optoelectronics. PMID:24533793

Ahmad, Nurul Fariha; Rusli, Nurul Izni; Mahmood, Mohamad Rusop; Yasui, Kanji; Hashim, Abdul Manaf

2014-01-01

401

Multiple temperature kinetic model and gas-kinetic method for hypersonic non-equilibrium flow computations  

E-print Network

Multiple temperature kinetic model and gas-kinetic method for hypersonic non-equilibrium flow. For the non-equilibrium flow computations, i.e., the nozzle flow and hypersonic rarefied flow over flat plate-kinetic method; Hypersonic and rarefied flows 1. Introduction The development of aerospace technology has

Xu, Kun

402

Automated Nondestructive Evaluation Method for Characterizing Ceramic and Metallic Hot Gas Filters  

SciTech Connect

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.

Ellingson, W.A.; Pastila, P.; Koehl, E.R.; Wheeler, B.; Deemer, C.; Forster, G.A.

2002-09-19

403

Demonstration of a Method to Determine Atmospheric Gas Concentration from Infrared Emission Spectra  

Microsoft Academic Search

The measurement techniques of trace gas pollutants such as O 3, CO and NH3 in the atmosphere near the ground have matured enough to ensure reliable human exposure assessments. However, no practical method has been identified to quantify the vertical extent of gaseous pollutants near the ground. One method, based upon passive remote sensing, might prove practical in measuring the

David W. DuBois

404

REVIEW OF METHODS OF OPTICAL GAS Detection by Direct Optical Spectroscopy, with Emphasis on Correlation Spectroscopy  

NASA Astrophysics Data System (ADS)

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.

Dakin, John P.; Chambers, Paul

405

Flammable gas safety program. Analytical methods development: FY 1994 progress report  

SciTech Connect

This report describes the status of developing analytical methods to account for the organic components in Hanford waste tanks, with particular focus on tanks assigned to the Flammable Gas Watch List. The methods that have been developed are illustrated by their application to samples obtained from Tank 241-SY-101 (Tank 101-SY).

Campbell, J.A.; Clauss, S.; Grant, K.; Hoopes, V.; Lerner, B.; Lucke, R.; Mong, G.; Rau, J.; Wahl, K.; Steele, R.

1994-09-01

406

Improved method of measurement for tritiated water standardization by internal gas proportional counting  

Microsoft Academic Search

Tritiated water has been standardized by internal gas counting following its chemical reduction to tritiated hydrogen by using a new tritium generator and an improved method of measurement. This method is based on the equality between the molar activities of the tritiated water and the tritiated hydrogen and is valid only when the reduction yield is unitary. It is simpler

D. Stanga; P. Cassette

2006-01-01

407

Method and apparatus to replace natural gas with vaporized fuel oil in a natural gas burner  

Microsoft Academic Search

The method, in general, includes, is mixing the fuel oil with a diluent, such as steam, vaporizing a portion of the mixed fuel oil in a vaporizer, separating the liquid from the vapor, maintaining the vapor at from about 50° to 300°F above the dew point of the mixed vapor and diluent at about 75 to 150 psig, above the

W. W. Hoehing; E. R. Johnson

1979-01-01

408

Thermal chemical recuperation method and system for use with gas turbine systems  

DOEpatents

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.

Yang, W.C.; Newby, R.A.; Bannister, R.L.

1999-04-27

409

Thermal chemical recuperation method and system for use with gas turbine systems  

DOEpatents

A system and method for efficiently generating power using a gas turbine, a steam generating system (20, 22, 78) and a reformer. The gas turbine receives a reformed fuel stream (74) and an air stream and produces shaft power and exhaust. Some of the thermal energy from the turbine exhaust is received by the reformer (18). 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.

Yang, Wen-Ching (Export, PA); Newby, Richard A. (Pittsburgh, PA); Bannister, Ronald L. (Winter Springs, FL)

1999-01-01

410

Method and apparatus for perforating at cutting with a solid fueled gas mixture  

SciTech Connect

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.

Woytek, A.J.; Lileck, J.T.; Steigerwalt, E.J.

1984-05-08

411

Human blood and environmental media screening method for pesticides and polychlorinated biphenyl compounds using liquid extraction and gas chromatography-mass spectrometry analysis.  

PubMed

Screening assessment methods have been developed for semi- and non-volatile persistent organic pollutants (POPs) for human blood and solid environmental media. The specific methodology is developed for measuring the presence of "native" compounds, specifically, a variety of organochlorine pesticides (OCPs), organophosphate pesticides (OPPs), and for polychlorinated biphenyls (PCBs). The method is demonstrated on anonymous Red Cross blood samples as well as two potential environmental sources, tracked in soil and dog hair. This work is based on previously developed methods for semi-volatile hydrocarbon exposure from fuels usage and similarly employs liquid solvent extraction, evaporative volume reduction. and subsequent specialized gas chromatography-mass spectrometry analysis (GC-MS). Standard curves, estimates of recovery efficiency, and specific GC-MS SIM quantification methods were developed for common pesticides including diazinon. aldrin, chlorpyrifos, malathion, dieldrin, DDT, permethrin, cyhalothrin, and cypermethrin, and for seven selected PCBs. Trace levels of certain PCBs and pesticides such as permethrin, dieldrin, malathion, lindane, diazinon, and chlorpyrifos were tentatively identified in anonymous blood samples as well as in two potential environmental sources. tracked in soil and dog hair. The method provides a simple screening procedure for various media and a variety of common organic pollutants without extensive sample preparation. It is meant to complement and augment data from more specific or complex methodology, to provide initial broad spectrum guidance for designing targeted experiments, and to provide confirmatory evidence for the usual metabolic biomarker measurements made to assess human exposure. PMID:11936688

Liu, Siming; Pleil, Joachim D

2002-03-25

412

Generalized average of signals (GAS) - a new method for denoising and phase detection  

NASA Astrophysics Data System (ADS)

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.

Malek, J.; Kolinsky, P.; Strunc, J.; Valenta, J.

2007-12-01

413

Modeling monthly pan evaporations using fuzzy genetic approach  

NASA Astrophysics Data System (ADS)

SummaryThis study investigates the ability of fuzzy genetic (FG) approach in estimation of monthly pan evaporations. Various monthly climatic data, that are, solar radiation, air temperature, relative humidity and wind speed from two stations, Antalya and Mersin, in Mediterranean Region of Turkey, were used as inputs to the FG technique so as to estimate monthly pan evaporations. In the first part of the study, FG models were compared with neuro-fuzzy (ANFIS), artificial neural networks (ANNs) and Stephens-Stewart (SS) methods in estimating pan evaporations of Antalya and Mersin stations, separately. Comparison of the models revealed that the FG models generally performed better than the ANFIS, ANN and SS models. In the second part of the study, models were compared to each other in two different applications. In the first application the input data of Antalya Station were used as inputs to the models to estimate pan evaporation data of Mersin Station. The pan evaporation data of Mersin Station were estimated using the input data of Antalya and Mersin stations in the second application. Comparison results indicated that the FG models performed better than the ANFIS and ANN models. Comparison of the accuracy of the applied models in estimating total pan evaporations showed that the FG model provided the closest estimate. It was concluded that monthly pan evaporations could be successfully estimated by the FG approach.

Ki?i, Özgür; Tombul, Mustafa

2013-01-01

414

Method of reducing temperature gradients in contained gas flows and its application to the control of sample temperatures in a gas flow at 300 °C  

Microsoft Academic Search

A simple method of reducing temperature gradients in contained gas flows is described. The method is used to reduce the temperature gradient within a contained gas flow at 300 °C by a factor of about 100 and applied to the control of the temperature of a sample in the cavity of an EPR spectrometer.

R. C. Kemp

1987-01-01

415

Design and performance of an absolute gas refractometer based on a synthetic pseudo-wavelength method.  

PubMed

We present a refractometer that is capable of measuring the refractive index of gases with an unambiguous range of 1.000395 and an uncertainty of 3.14×10(-8) at 633 nm. The measurement range was extended via the combination of the vacuum cells according to the proposed synthetic pseudo-wavelength (SPW) method. The basic principles of the SPW method and the design of the gas refractometer are presented in detail. The performance of the refractometer was verified in the measurements of dry air, nitrogen gas, and ambient air under different environmental conditions. No gas-filling or pumping processes were required during the measurements; so one measurement could be completed within 70 s. Compared with existing refractometers, the method reported here holds advantages in its large unambiguous measuring range, fast speed, high accuracy, and simple instrumentation design. PMID:23736319

Zhang, Jitao; Huang, Pei; Li, Yan; Wei, Haoyun

2013-06-01

416

Infrared thermography of evaporative fluxes and dynamics of salt deposition on heterogeneous porous surfaces  

NASA Astrophysics Data System (ADS)

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.

Nachshon, Uri; Shahraeeni, Ebrahim; Or, Dani; Dragila, Maria; Weisbrod, Noam

2011-12-01

417

A method to estimate weight and dimensions of aircraft gas turbine engines. Volume 1: Method of analysis  

NASA Technical Reports Server (NTRS)

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.

Pera, R. J.; Onat, E.; Klees, G. W.; Tjonneland, E.

1977-01-01

418

Apparatus For The Liquefaaction Of Natural Gas And Methods Relating To Same  

DOEpatents

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.

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

419

Apparatus For The Liquefaaction Of Natural Gas And Methods Relating To Same  

DOEpatents

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.

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

420

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

DOEpatents

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.

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

421

Apparatus For The Liquefaaction Of Natural Gas And Methods Relating To Same  

DOEpatents

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.

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

422

Comparison of Several Methods of Cyclic De-Icing of a Gas-Heated Airfoil  

NASA Technical Reports Server (NTRS)

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.

Gray, Vernon H.; Bowden, Dean T.

1953-01-01

423

Thermal evaporation of spherical clouds - Effects of viscous stresses  

NASA Technical Reports Server (NTRS)

The thermal evaporation of a cold spherical cloud embedded in hot gas is analyzed, including the effects of viscous stresses as well as 'saturation' of the conductive heat flux, for the case of equal electron and ion temperatures. The relevant transport properties for an H-He plasma are discussed, including the modification of these transport coefficients when temperature or velocity gradients become large. The fluid-dynamical equations for steady spherical evaporation are given and cast into dimensinless form. Numerical integration of these equations and the results are discussed, emphasizing the novel features of the viscous solutions, astrophysical implications, and uncertainties in the physics.

Giuliani, J. L., Jr.; Draine, B. T.

1984-01-01

424

Chemical and isotopic fractionations by evaporation and their cosmochemical implications  

NASA Astrophysics Data System (ADS)

A kinetic model for evaporation of a multi-component condensed phase with a fixed rate constant of the reaction is developed. A binary system with two isotopes for one of the components undergoing simple thermal histories (e.g., isothermal heating) is investigated in order to evaluate the extent of isotopic and chemical fractionations during evaporation. Diffusion in the condensed phase and the effect of back reaction from ambient gas are taken into consideration. Chemical and isotopic fractionation factors and the Péclet number for evaporation are the three main parameters that control the fractionation. Dust enrichment factor (?), the ratio of the initial dust quantity to that required for attainment of gas-dust equilibrium, is critical when back reactions become significant. Dust does not reach equilibrium with gas at ? < 1. Notable chemical and isotopic fractionations usually take place under these conditions. There are two circumstances in which isotopic fractionation of a very volatile element does not accompany chemical fractionation during isothermal heating. One is free evaporation when diffusion in the condensed phase is very slow (? = 0), and the other is evaporation in the presence of ambient gas (? > 0). In the former case, a quasi-steady state in the diffusion boundary layer is maintained for isotopic fractionation but not for chemical fractionation. In the latter case, the back reaction brings the strong isotopic fractionation generated in the earlier stage of evaporation back to a negligibly small value in the later stage before complete evaporation. The model results are applied to cosmochemical fractionation of volatile elements during evaporation from a condensed phase that can be regarded as a binary solution phase. The wide range of potassium depletion without isotopic fractionation in various types of chondrules (Alexander et al., 2000) is explained by instantaneous heating followed by cooling in a closed system with various degrees of dust enrichment (? = 0.001-10) and cooling rates of less than ˜5°C/min. The extent of decoupling between isotopic and chemical fractionations of various elements in chondrules and matrix minerals may constrain the time scale and the conditions of heating and cooling processes in the early solar nebula.

Ozawa, Kazuhito; Nagahara, Hiroko

2001-07-01

425

Magnesium, Silicon, and Oxygen Isotopic Consequences of CAI Evaporation and Inversion for Primordial Melt Compositions  

NASA Astrophysics Data System (ADS)

We show how realistic activity-composition relationships in CMAS melts can be used to invert silicon- and magnesium-isotope ratios for evaporation histories of CAIs. Results suggest igneous CAIs were indeed condensates from a solar gas.

Young, E. D.; Shahar, A.

2012-03-01

426

Evaporation and deposition of alkyl-capped silicon nanocrystals in ultrahigh vacuum.  

PubMed

Nanocrystals are under active investigation because of their interesting size-dependent properties and potential applications. Silicon nanocrystals have been studied for possible uses in optoelectronics, and may be relevant to the understanding of natural processes such as lightning strikes. Gas-phase methods can be used to prepare nanocrystals, and mass spectrometric techniques have been used to analyse Au and CdSe clusters. However, it is difficult to study nanocrystals by such methods unless they are synthesized in the gas phase. In particular, pre-prepared nanocrystals are generally difficult to sublime without decomposition. Here we report the observation that films of alkyl-capped silicon nanocrystals evaporate upon heating in ultrahigh vacuum at 200 degrees C, and the vapour of intact nanocrystals can be collected on a variety of solid substrates. This effect may be useful for the controlled preparation of new quantum-confined silicon structures and could facilitate their mass spectroscopic study and size-selection. PMID:18654345

Chao, Yimin; Siller, Lidija; Krishnamurthy, Satheesh; Coxon, Paul R; Bangert, Ursel; Gass, Mhairi; Kjeldgaard, Lisbeth; Patole, Samson N; Lie, Lars H; O'Farrell, Norah; Alsop, Thomas A; Houlton, Andrew; Horrocks, Benjamin R

2007-08-01

427

Efficient method of gas laser pumping by an electron beam in the SIGE-1 experimental setup  

SciTech Connect

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}.

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

428

Fundamental study of evaporation model in micron pore  

E-print Network

................................................................ 10 Phase-change Phenomena in Meniscus.................................................11 Evaporation Model..................................................................................... 16 Evaporation Model Based on Kinetic Theory... .......................................................................... 51 Evaporation Rate and Meniscus Profile in Pore......................................... 51 Total Evaporation Rate in Pore .................................................................. 78 Application of Evaporation Model to Heat Pipe...

Oinuma, Ryoji

2004-11-15

429

WATER RESOURCES RESEARCH, VOL. 17, NO. S, PAGES 1453-1462, OCTOBER 1981 Operational Estimates ofLake Superior Evaporation  

E-print Network

Lake Superior Evaporation Based on IFYGL Findings JAN A. DERECKI NatioMI Oceanic and Atmospheric Administration, Great Lakes Enllironmental Research Laboratory AM Arbor, Michigan 48104 Monthly evapor~tion from Lake.SS transfer method. This method permits timely evaporation estimates from readily available land

430

A unified approach to predict evaporation losses in evaporative heat exchangers  

Microsoft Academic Search

In this paper, the rules of thumb used to predict evaporation losses in different evaporative heat exchangers are unified. The accurate prediction of all aspects of evaporative heat exchanger behavior is very important. Accurately predicting evaporation losses is significant since water, in this class of heat exchangers, is cooled primarily by evaporation of a portion of the circulating water that

Bilal Ahmed Qureshi; Syed M. Zubair

2011-01-01

431

A mass balance method for non-intrusive measurements of surface-air trace gas exchange  

NASA Astrophysics Data System (ADS)

A mass balance method is described for calculating gas production from a surface or volume source in a small test plot from measurements of differences in the horizontal fluxes of the gas across upwind and downwind boundaries. It employs a square plot, 24 m×24 m, with measurements of gas concentration at four heights (up to 3.5 m) along each of the four boundaries. Gas concentrations are multiplied by the appropriate vector winds to yield the horizontal fluxes at each height on each boundary. The difference between these fluxes integrated over downwind and upwind boundaries represents production. Illustrations of the method, which involve exchanges of methane and carbon dioxide, are drawn from experiments with landfills, pastures and grazing animals. Tests included calculation of recovery rates from known gas releases and comparisons with a conventional micrometeorological approach and a backward dispersion model. The method performed satisfactorily in all cases. Its sensitivity for measuring exchanges of CO 2, CH 4 and N 2O in various scenarios was examined. As employed by us, the mass balance method can suffer from errors arising from the large number of gas analyses required for a flux determination, and becomes unreliable when there are light winds and variable wind directions. On the other hand, it is non-disturbing, has a simple theoretical basis, is independent of atmospheric stability or the shape of the wind profile, and is appropriate for flux measurement in situations where conventional micrometeorological methods can not be used, e.g. for small plots, elevated point sources, and heterogeneous surface sources.

Denmead, O. T.; Harper, L. A.; Freney, J. R.; Griffith, D. W. T.; Leuning, R.; Sharpe, R. R.

432

Evaporation of pure liquid sessile and spherical suspended drops: a review.  

PubMed

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

Erbil, H Yildirim

2012-01-15

433

How over 100 years of climate variability may affect estimates of potential evaporation  

NASA Astrophysics Data System (ADS)

Hydrological modeling frameworks require an accurate representation of evaporation fluxes for appropriate quantification of e.g. the soil moisture budget, droughts, recharge and groundwater processes. Many frameworks have used the concept of potential evaporation, often estimated for different vegetation classes by multiplying the evaporation from a reference surface ("reference evaporation") with crop specific scaling factors ("crop factors"). Though this two-step potential evaporation approach undoubtedly has practical advantages, the empirical nature of both reference evaporation methods and crop factors limits its usability in extrapolations and non-stationary climatic conditions. In this paper we assess the sensitivity of potential evaporation estimates for different vegetation classes using the two-step approach when calibrated using a non-stationary climate. We used the past century's time series of observed climate, containing non-stationary signals of multi-decadal atmospheric oscillations, global warming, and global dimming/brightening, to evaluate the sensitivity of potential evaporation estimates to the choice and length of the calibration period. We show that using empirical coefficients outside their calibration range may lead to systematic differences between process-based and empirical reference evaporation methods, and systematic errors in estimated potential evaporation components. Such extrapolations of time-variant model parameters are not only relevant for the calculation of potential evaporation, but also for hydrological modeling in general, and they may limit the temporal robustness of hydrological models.

Bartholomeus, R. P.; Stagge, J. H.; Tallaksen, L. M.; Witte, J. P. M.

2014-09-01

434

Subsurface heating effects during pulsed laser evaporation of materials  

NASA Astrophysics Data System (ADS)

We have theoretically and experimentally investigated the thermal effects of targets evaporated by nanosecond laser pulses. The subsurface temperatures were calculated to be higher than the surface temperatures during planar surface evaporation of the target material. While the evaporating surface is being cooled due to the latent heat of vaporization, subsurface superheating occurs due to a finite absorption depth of the laser beam. The temperature profiles of silicon targets irradiated by nanosecond laser pulses were determined by solving the one-dimensional heat flow equation using an implicit finite difference method. The subsurface superheating increased at higher energy densities, and decreased with increasing absorption coefficient of the material. This internal heating of the target during pulsed laser irradiation can be correlated with the explosive removal of material from the target. This may lead to deposition of small particles on films fabricated by the pulsed laser evaporation technique.

Singh, Rajiv K.; Bhattacharya, D.; Narayan, J.

1990-11-01

435

Building microscopic soccer balls with evaporating colloidal fakir drops  

PubMed Central

Evaporation-driven particle self-assembly can be used to generate three-dimensional microstructures. We present a unique method to create 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 microstructured surface, on which the droplet remains 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, particle size, and number of particles in the system. PMID:23010925

Marin, Alvaro G.; Gelderblom, Hanneke; Susarrey-Arce, Arturo; van Houselt, Arie; Lefferts, Leon; Gardeniers, Johannes G. E.; Lohse, Detlef; Snoeijer, Jacco H.

2012-01-01

436

Evaporating Spray in Supersonic Streams Including Turbulence Effects  

NASA Technical Reports Server (NTRS)

Evaporating spray plays an important role in spray combustion processes. This paper describes the development of a new finite-conductivity evaporation model, based on the two-temperature film theory, for two-phase numerical simulation using Eulerian-Lagrangian method. The model is a natural extension of the T-blob/T-TAB atomization/spray model which supplies the turbulence characteristics for estimating effective thermal diffusivity within the droplet phase. Both one-way and two-way coupled calculations were performed to investigate the performance of this model. Validation results indicate the superiority of the finite-conductivity model in low speed parallel flow evaporating sprays. High speed cross flow spray results indicate the effectiveness of the T-blob/T-TAB model and point to the needed improvements in high speed evaporating spray modeling.

Balasubramanyam, M. S.; Chen, C. P.

2006-01-01

437

Building micro-soccer-balls with evaporating colloidal fakir drops  

E-print Network

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.

Marin, Alvaro G; Gelderblom, Hanneke; van Houselt, Arie; Lefferts, Leon; Gardeniers, Han; Lohse, Detlef; Snoeijer, Jacco

2012-01-01

438

Building micro-soccer-balls with evaporating colloidal fakir drops  

E-print Network

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.

Alvaro G. Marin; Arturo Susarrey-Arce; Hanneke Gelderblom; Arie van Houselt; Leon Lefferts; Han Gardeniers; Detlef Lohse; Jacco Snoeijer

2012-03-20