Sample records for vapor pressure perfluorocarbons

  1. Surface tension of water in the presence of perfluorocarbon vapors. (United States)

    Chernyshev, Vasiliy S; Skliar, Mikhail


    Fluorocarbons are highly hydrophobic, biocompatible compounds with a variety of medical applications. Despite significant interest, the study of interfacial properties of fluorocarbons in aqueous systems has received limited attention. In this study, we investigate the influence of perfluoropentane and perfluorohexane vapors on the surface tension of water at room temperature. The results show a substantial decrease in the surface tension of water in the presence of perfluorocarbon vapors. In the investigated range of partial pressures up to the saturation value, a linear correlation between the surface tension and the partial pressure was found. This suggests that an adsorbed perfluorocarbon layer is formed on the surface of water. For comparison, the effect of the perfluorocarbon vapor on the surface tension of methanol was also investigated and a similar dependence was observed. Our results indicate that the stability and dynamic transitions of fluorocarbon colloids, which may be dispersed under physiological conditions as microdroplets, bubbles, or their combination, are likely affected by the composition of liquid and gas phases.

  2. Vaporization of perfluorocarbon droplets using optical irradiation. (United States)

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


    Micron-sized liquid perfluorocarbon (PFC) droplets are currently being investigated as activatable agents for medical imaging and cancer therapy. After injection into the bloodstream, superheated PFC droplets can be vaporized to a gas phase for ultrasound imaging, or for cancer therapy via targeted drug delivery and vessel occlusion. Droplet vaporization has been previously demonstrated using acoustic methods. We propose using laser irradiation as a means to induce PFC droplet vaporization using a method we term optical droplet vaporization (ODV). In order to facilitate ODV of PFC droplets which have negligible absorption in the infrared spectrum, optical absorbing nanoparticles were incorporated into the droplet. In this study, micron-sized PFC droplets loaded with silica-coated lead sulfide (PbS) nanoparticles were evaluated using a 1064 nm laser and ultra-high frequency photoacoustic ultrasound (at 200 and 375 MHz). The photoacoustic response was proportional to nanoparticle loading and successful optical droplet vaporization of individual PFC droplets was confirmed using photoacoustic, acoustic, and optical measurements. A minimum laser fluence of 1.4 J/cm(2) was required to vaporize the droplets. The vaporization of PFC droplets via laser irradiation can lead to the activation of PFC agents in tissues previously not accessible using standard ultrasound-based techniques.

  3. Vaporization of perfluorocarbon droplets using optical irradiation

    National Research Council Canada - National Science Library

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


    .... Droplet vaporization has been previously demonstrated using acoustic methods. We propose using laser irradiation as a means to induce PFC droplet vaporization using a method we term optical droplet vaporization (ODV...

  4. Gasoline Reid Vapor Pressure (United States)

    EPA regulates the vapor pressure of gasoline sold at retail stations during the summer ozone season to reduce evaporative emissions from gasoline that contribute to ground-level ozone and diminish the effects of ozone-related health problems.

  5. Vaporization dynamics of volatile perfluorocarbon droplets: A theoretical model and in vitro validation

    Energy Technology Data Exchange (ETDEWEB)

    Doinikov, Alexander A., E-mail:; Bouakaz, Ayache [Inserm U930, Université François Rabelais, Tours 37044 (France); Sheeran, Paul S.; Dayton, Paul A. [Joint Department of Biomedical Engineering, The University of North Carolina and North Carolina State University, Chapel Hill, North Carolina 27599 (United States)


    Purpose: Perfluorocarbon (PFC) microdroplets, called phase-change contrast agents (PCCAs), are a promising tool in ultrasound imaging and therapy. Interest in PCCAs is motivated by the fact that they can be triggered to transition from the liquid state to the gas state by an externally applied acoustic pulse. This property opens up new approaches to applications in ultrasound medicine. Insight into the physics of vaporization of PFC droplets is vital for effective use of PCCAs and for anticipating bioeffects. PCCAs composed of volatile PFCs (with low boiling point) exhibit complex dynamic behavior: after vaporization by a short acoustic pulse, a PFC droplet turns into a vapor bubble which undergoes overexpansion and damped radial oscillation until settling to a final diameter. This behavior has not been well described theoretically so far. The purpose of our study is to develop an improved theoretical model that describes the vaporization dynamics of volatile PFC droplets and to validate this model by comparison with in vitro experimental data. Methods: The derivation of the model is based on applying the mathematical methods of fluid dynamics and thermodynamics to the process of the acoustic vaporization of PFC droplets. The used approach corrects shortcomings of the existing models. The validation of the model is carried out by comparing simulated results with in vitro experimental data acquired by ultrahigh speed video microscopy for octafluoropropane (OFP) and decafluorobutane (DFB) microdroplets of different sizes. Results: The developed theory allows one to simulate the growth of a vapor bubble inside a PFC droplet until the liquid PFC is completely converted into vapor, and the subsequent overexpansion and damped oscillations of the vapor bubble, including the influence of an externally applied acoustic pulse. To evaluate quantitatively the difference between simulated and experimental results, the L2-norm errors were calculated for all cases where the

  6. Vaporization dynamics of volatile perfluorocarbon droplets: A theoretical model and in vitro validation (United States)

    Doinikov, Alexander A.; Sheeran, Paul S.; Bouakaz, Ayache; Dayton, Paul A.


    Purpose: Perfluorocarbon (PFC) microdroplets, called phase-change contrast agents (PCCAs), are a promising tool in ultrasound imaging and therapy. Interest in PCCAs is motivated by the fact that they can be triggered to transition from the liquid state to the gas state by an externally applied acoustic pulse. This property opens up new approaches to applications in ultrasound medicine. Insight into the physics of vaporization of PFC droplets is vital for effective use of PCCAs and for anticipating bioeffects. PCCAs composed of volatile PFCs (with low boiling point) exhibit complex dynamic behavior: after vaporization by a short acoustic pulse, a PFC droplet turns into a vapor bubble which undergoes overexpansion and damped radial oscillation until settling to a final diameter. This behavior has not been well described theoretically so far. The purpose of our study is to develop an improved theoretical model that describes the vaporization dynamics of volatile PFC droplets and to validate this model by comparison with in vitro experimental data. Methods: The derivation of the model is based on applying the mathematical methods of fluid dynamics and thermodynamics to the process of the acoustic vaporization of PFC droplets. The used approach corrects shortcomings of the existing models. The validation of the model is carried out by comparing simulated results with in vitro experimental data acquired by ultrahigh speed video microscopy for octafluoropropane (OFP) and decafluorobutane (DFB) microdroplets of different sizes. Results: The developed theory allows one to simulate the growth of a vapor bubble inside a PFC droplet until the liquid PFC is completely converted into vapor, and the subsequent overexpansion and damped oscillations of the vapor bubble, including the influence of an externally applied acoustic pulse. To evaluate quantitatively the difference between simulated and experimental results, the L2-norm errors were calculated for all cases where the

  7. The efficiency and stability of bubble formation by acoustic vaporization of submicron perfluorocarbon droplets

    NARCIS (Netherlands)

    Reznik, Nikita; Shpak, O.; Gelderblom, E.C.; Williams, Ross; de Jong, N.; Versluis, Andreas Michel; Burns, Peter N.


    Submicron droplets of liquid perfluorocarbon converted into microbubbles with applied ultrasound have been studied, for a number of years, as potential next generation extravascular ultrasound contrast agents. In this work, we conduct an initial ultra-high-speed optical imaging study to examine the

  8. Vapor pressures and enthalpies of vaporization of azides

    Energy Technology Data Exchange (ETDEWEB)

    Verevkin, Sergey P., E-mail: [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Emel' yanenko, Vladimir N. [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Algarra, Manuel [Centro de Geologia do Porto, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Manuel Lopez-Romero, J. [Department of Organic Chemistry, University of Malaga. Campus de Teatinos s/n, 29071 Malaga (Spain); Aguiar, Fabio; Enrique Rodriguez-Borges, J.; Esteves da Silva, Joaquim C.G. [Centro de Investigacao em Quimica (CIQ-UP), Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)


    Highlights: > We prepared and measured vapor pressures and vaporization enthalpies of 7 azides. > We examined consistency of new and available in the literature data. > Data for geminal azides and azido-alkanes selected for thermochemical calculations. - Abstract: Vapor pressures of some azides have been determined by the transpiration method. The molar enthalpies of vaporization {Delta}{sub l}{sup g}H{sub m} of these compounds were derived from the temperature dependencies of vapor pressures. The measured data sets were successfully checked for internal consistency by comparison with vaporization enthalpies of similarly structured compounds.

  9. Estimated vapor pressure for WTP process streams

    Energy Technology Data Exchange (ETDEWEB)

    Pike, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    Design assumptions during the vacuum refill phase of the Pulsed Jet Mixers (PJMs) in the Hanford Waste Treatment and Immobilization Plant (WTP) equate the vapor pressure of all process streams to that of water when calculating the temperature at which the vacuum refill is reduced or eliminated. WTP design authority asked the authors to assess this assumption by performing calculations on proposed feed slurries to calculate the vapor pressure as a function of temperature. The vapor pressure was estimated for each WTP waste group. The vapor pressure suppression caused by dissolved solids is much greater than the increase caused by organic components such that the vapor pressure for all of the waste group compositions is less than that of pure water. The vapor pressure for each group at 145°F ranges from 81% to 98% of the vapor pressure of water. If desired, the PJM could be operated at higher temperatures for waste groups with high dissolved solids that suppress vapor pressure. The SO4 group with the highest vapor pressure suppression could be operated up to 153°F before reaching the same vapor pressure of water at 145°F. However, most groups would reach equivalent vapor pressure at 147 to 148°F. If any of these waste streams are diluted, the vapor pressure can exceed the vapor pressure of water at mass dilution ratios greater than 10, but the overall effect is less than 0.5%.


    Energy Technology Data Exchange (ETDEWEB)

    Eric M. Suuberg; Vahur Oja


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

  11. Ultrasonically-Induced Vaporization of Perfluorocarbon Droplets for Occlusion Therapy of Breast Cancer (United States)


    414. Halliday D, Resnick R, Walker J. Fundamentals of physics. New York: John Wiley & Sons, Inc., 1997:485. Hayduk W, Laudie H. Prediction of diffusion...gas law pV 5 NRT ( Halliday et al. 1997), where p is atmospheric pressure [N m22], V is volume to be calculated [m3], N is the amount of droplet

  12. Vapor Pressure Data Analysis and Statistics (United States)


    there were flaws in the original data prior to its publication. 3. FITTING METHODS Our process for correlating experimental vapor pressure ...2. Penski, E.C. Vapor Pressure Data Analysis Methodology, Statistics, and Applications; CRDEC-TR-386; U.S. Army Chemical Research, Development, and... Chemical Biological Center: Aberdeen Proving Ground, MD, 2006; UNCLASSIFIED Report (ADA447993). 11. Kemme, H.R.; Kreps, S.I. Vapor Pressure of

  13. In Vivo Assessment of the Potential for Renal Bio-Effects from the Vaporization of Perfluorocarbon Phase-Change Contrast Agents. (United States)

    Nyankima, A Gloria; Rojas, Juan D; Cianciolo, Rachel; Johnson, Kennita A; Dayton, Paul A


    Low-boiling-point perfluorocarbon phase-change contrast agents (PCCAs) provide an alternative to microbubble contrast agents. Although parameter ranges related to in vivo bio-effects of microbubbles are fairly well characterized, few studies have been done to evaluate the potential of bio-effects related to PCCAs. To bridge this gap, we present an assessment of biological effects (e.g., hemorrhage) related to acoustically excited PCCAs in the rodent kidney. The presence or absence of bio-effects was observed after sonication with various perfluorocarbon core PCCAs (decafluorobutane, octafluoropropane or a 1:1 mixture) and as a function of activation pulse mechanical index (MI; minimum activation threshold, which was a moderate MI of 0.81-1.35 vs. a clinical maximum of 1.9). Bio-effects on renal tissue were assessed through hematology and histology including measurement of blood creatinine levels and the quantity of red blood cell (RBC) casts present in hematoxylin and eosin-stained kidney tissue sections after sonication. Short-term (24 h) and long-term (2 and 4 wk) analyses were performed after treatment. Results indicated that bio-effects from PCCA vaporization were not observed at lower mechanical indices. At higher mechanical indices, bio-effects were observed at 24 h, although these were not observable 2 wk after treatment. Copyright © 2018. Published by Elsevier Inc.

  14. Vapor Pressures of Several Commercially Used Alkanolamines

    NARCIS (Netherlands)

    Klepacova, Katarina; Huttenhuis, Patrick J. G.; Derks, Peter W. J.; Versteeg, Geert F.; Klepáčová, Katarína

    For the design of acid gas treating processes, vapor-liquid equilibrium (VLE) data must be available of the solvents to be applied. In this study the vapor pressures of seven frequently industrially used alkanolamines (diethanolamine, N-methylethanolamine, N,N-dimethylethanolamine,

  15. Excessively High Vapor Pressure of Al-based Amorphous Alloys


    Jeong, Jae; Lee, Sung; Jeon, Je-Beom; Kim, Suk


    Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the va...

  16. Excessively High Vapor Pressure of Al-based Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Jae Im Jeong


    Full Text Available Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the vapor pressure of crystalline Al near its melting temperature, 873 K. Our results strongly suggest the possibility of fabricating nanocrystallites or thin films by evaporation at low temperatures.

  17. Determination of Cannabinoid Vapor Pressures to Aid in Vapor Phase Detection of Intoxication. (United States)

    Lovestead, Tara M; Bruno, Thomas J


    The quest for a reliable means to detect cannabis intoxication with a breathalyzer is ongoing. To design such a device, it is important to understand the fundamental thermodynamics of the compounds of interest. The vapor pressures of two important cannabinoids, cannabidiol (CBD) and Δ9-tetrahydrocannabinol (Δ9-THC), are presented, as well as the predicted normal boiling temperature (NBT) and the predicted critical constants (these predictions are dependent on the vapor pressure data). The critical constants are typically necessary to develop an equation of state (EOS). EOS-based models can provide estimations of thermophysical properties for compounds to aid in designing processes and devices. An ultra-sensitive, quantitative, trace dynamic headspace analysis sampling called porous layered open tubular-cryoadsorption (PLOT-cryo) was used to measure vapor pressures of these compounds. PLOT-cryo affords short experiment durations compared to more traditional techniques for vapor pressure determination (minutes versus days). Additionally, PLOT-cryo has the inherent ability to stabilize labile solutes because collection is done at reduced temperature. The measured vapor pressures are approximately 2 orders of magnitude lower than those measured for n-eicosane, which has a similar molecular mass. Thus, the difference in polarity of these molecules must be impacting the vapor pressure dramatically. The vapor pressure measurements are presented in the form of Clausius-Clapeyron (or van't Hoff) equation plots. The predicted vapor pressures that would be expected at near ambient conditions (25 °C) are also presented.

  18. LOX vaporization in high-pressure, hydrogen-rich gas (United States)

    Litchford, Ron J.; Jeng, San-Mou


    LOX droplet vaporization in high-pressure hydrogen-rich gas is analyzed, with special attention to thermodynamic effects which compel the surface to heat to the critical state and to supercritical vaporization processes on heating to criticality. Subcritical vaporization is modeled using a quasi-steady diffusion-controlled gas-phase transport formulation coupled to an effective-conductivity internal-energy-transport model accounting for circulation effects. It is demonstrated how the droplet surface might heat to the critical state, for ambient pressures slightly greater than the critical pressure of oxygen, such that the bulk of propellant within the droplet remains substantially below the critical mixing temperature.

  19. Vapor Pressure of Bis-(2-chloroethyl)ethylamine (HN1) (United States)


    The spectra that were obtained to compute the vapor-phase absorptivity coefficient showed traces of water vapor that purged during the first day of... barometer . Bath temperature, gas flow rate, and ambient pressure were recorded at 4 s intervals using a National Instruments (Austin, TX) LabVIEW

  20. Metal vapor condensation under high pressure (mercury vapor to 500 psia). [Heat transfer coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, S.; Bonilla, C.F.


    Mercury vapor up to 500 psia was condensed outside a cylindrical tube in both horizontal and vertical positions. Results show consistently low heat transfer coefficients compared to Nusselt's theory. Two auxiliary mercury vapor condensers downstream of the boiler vent were used to control and safeguard the system. Constantan wires were spot welded on the surface inside the test condenser tube. The heat flux ranged from 20,000 to 45,000 Btu/h-ft/sup 2/ and the temperature differences between vapor and condensing wall from 6 to 50/sup 0/F. The condensation heat transfer coefficients, ranging from 850 to 3,500 Btu/h-/sup 0/F-ft/sup 2/, are only about 3 to 9 percent of those predicted by Nusselt's theory. Due to the positive pressure in the system for most test runs, the chance of any in-leakage of noncondensable gases into the boiler is extremely small. Since no substantial change of heat transfer rate resulted from wide variations in the heat load on the reflux condenser at some specific heat flux on the test condenser tube, the low heat transfer rate of mercury vapor condensation was not due to the presence of any non-condensable gas. The test data for high vapor pressure up to 500 psia reveal that the heat transfer coefficient is independent of the vapor pressure level. The condensation coefficients calculated based on kinetic theory are much smaller than unity and decreasewith vapor pressure. It is hypothesized that dimer content in the metal vapor phase might behave as non-condensable or semi-condensable gas and create a diffusional barrier at the vapor-liquid interface near the condensate film. This dimer vapor could be the main cause of interfacial resistance during metal vapor condensation process. 41 figures, 7 tables, 58 references. (DLC)

  1. Using Dalton's Law of Partial Pressures to Determine the Vapor Pressure of a Volatile Liquid (United States)

    Hilgeman, Fred R.; Bertrand, Gary; Wilson, Brent


    This experiment, designed for a general chemistry laboratory, illustrates the use of Dalton's law of partial pressures to determine the vapor pressure of a volatile liquid. A predetermined volume of air is injected into a calibrated tube filled with a liquid whose vapor pressure is to be measured. The volume of the liquid displaced is greater than…

  2. Vapor pressure and intramolecular hydrogen bonding in fluorotelomer alcohols. (United States)

    Krusic, Paul J; Marchione, Alexander A; Davidson, Fredric; Kaiser, Mary A; Kao, Chien-Ping C; Richardson, Raymond E; Botelho, Miguel; Waterland, Robert L; Buck, Robert C


    Vapor pressure and aqueous solubility are important parameters used to estimate the potential for transport of chemical substances in the atmosphere. For fluorotelomer alcohols (FTOHs), currently under scrutiny by environmental scientists as potential precursors of persistent perfluorocarboxylates (PFCAs), vapor pressure is the more significant property since these compounds are only very sparingly soluble in water. We have measured the vapor pressures of a homologous series of fluorotelomer alcohols, F(CF2CF2)nCH2CH2OH (n = 2-5), in the temperature range 21-250 degrees C by three independent methods: (a) a method suitable for very low vapor pressures at ambient temperatures (gas-saturation method), (b) an improved boiling point method at controlled pressures (Scott method), and (c) a novel method, requiring milligram quantities of substance, based on gas-phase NMR, a technique largely unfamiliar to chemists and holding promise for studies of relevance to environmental chemistry. The concordant values obtained indicate that recently published vapor pressure data overestimate the vapor pressure at ambient temperature, and therefore the volatility, of this series of fluorinated compounds. It was suggested that substantial intramolecular -O-H...F- hydrogen bonding between the hydroxylic proton and the two fluorines next to the ethanol moiety was responsible for their putative high volatility. Therefore, we have used gas-phase NMR, gas-phase FTIR, 2D NMR heteronuclear Overhauser effect measurements, and high-level ab initio computations to investigate the intramolecular hydrogen bonding in fluorotelomer alcohols. Our studies unequivocally show that hydrogen bonding of this type is not significant and cannot contribute to and cause unusual volatility. The substantially lower vapor pressure at ambient temperatures than previously reported resulting from our work is important in developing a valid understanding of the environmental transport behavior of this class of

  3. Vapor phase growth of functional pentacene films at atmospheric pressure

    NARCIS (Netherlands)

    Rolin, C.; Vasseur, K.; Niesen, B.; Willegems, M.; Müller, R.; Steudel, S.; Genoe, J.; Heremans, P.


    Compared to traditional vacuum evaporation techniques for small organic molecules, organic vapor phase deposition (OVPD) possesses a extra processing parameter: the pressure of process gas Pch. Here, the influence of large Pch variations (from 0.1 mbar to atmospheric pressure) on pentacene thin film

  4. Thermogravimetric study of vapor pressure of TATP synthesized without recrystallization. (United States)

    Mbah, Jonathan; Knott, Debra; Steward, Scott


    This study aims at characterizing the vapor pressure signatures generated by triacetone triperoxide (TATP) that was synthesized without recrystallization by thermogravimmetric analysis (TGA) for exploitation by standoff detection technologies of explosive devices. The thermal behavior of the nonrecrystallized sample was compared with reported values. Any phase change, melting point and decomposition identification were studied by differential scanning calorimeter. Vapor pressures were estimated by the Langmuir method of evaporation from an open surface in a vacuum. Vapor pressures of TATP at different temperatures were calculated using the linear logarithmic relationship obtained from benzoic acid reference standard. Sublimation of TATP was found to follow apparent zero-order kinetics and sublimes at steady rates at 298 K and above. While the enthalpy of sublimation found, 71.7 kJ mol(-1), is in agreement with reported values the vapor pressures deviated significantly. The differences in the vapor pressures behavior are attributable to the synthesis pathway chosen in this study. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. A new generalized correlation for accurate vapor pressure

    Directory of Open Access Journals (Sweden)

    Luis Fernando Cardona Palacio


    Full Text Available In this work, a new generalized correlation for pure substances is proposed for the estimation of vapor pressure, applicable in wide temperature range. Was used equilibrium liquid-vapor data with 28 refrigerants and minimizing the sum of the squares of the relative deviation in liquid-vapour pressure were determined the parameters and constants characteristics of the new equation and generalized for any pure substance using the acentric factor. Vapor pressure predictions were made for 45 pure substances who they didn´t not participate in the minimization, generated percent relative average deviation of 1.6073%. The results were compared with others equations for calculating the vapor pressure and  the  comparison  indicates  that  the  proposed  method provide  more  accurate  results  than  other  methods  used  in  this  work. Finally, the calculations of enthalpies of vaporization were done with deviations of 0.880% and the Waring criterion was applied to check the constants presed in this paper

  6. Atmospheric sugar alcohols: evaporation rates and saturation vapor pressures

    DEFF Research Database (Denmark)

    Bilde, Merete; Zardini, Alessandro Alessio; Hong, Juan

    volatile organic molecules. Saturation vapor pressure and the associated temperature dependence (dH) are key parameters for improving predictive atmospheric models. In this work we combine experiments and thermodynamic modeling to investigate these parameters for a series of polyols, so-called sugar...... are allowed to evaporate in a laminar flow reactor, and changes in particle size as function of evaporation time are determined using a scanning mobility particle sizer system. In this work saturation vapor pressures of sugar alcohols at several temperatures have been inferred from such measurements using...

  7. 46 CFR 154.438 - Design vapor pressure. (United States)


    ... Independent Tank Type A § 154.438 Design vapor pressure. (a) If the surface of an independent tank type A are mostly flat surfaces,the Po must not exceed 69 kPa gauge (10 psig). (b) If the surfaces of an independent tank type A are formed by bodies of revolution, the design calculation of the Po must be specially...

  8. Dynamic response of vaporizing droplet to pressure oscillation (United States)

    Yuan, Lei; Shen, Chibing; Zhang, Xinqiao


    Combustion instability is a major challenge in the development of the liquid propellant engines, and droplet vaporization is viewed as a potential mechanism for driving instabilities. Based on the previous work, an unsteady droplet heating and vaporization model was developed. The model and numerical method are validated by experimental data available in literature, and then the oscillatory vaporization of n-Heptane droplet exposed to unsteady harmonic nitrogen atmosphere was numerically investigated over a wide range of amplitudes and frequencies. Also, temperature variations inside the droplet were demonstrated under oscillation environments. It was found that the thermal wave is attenuated with significantly reduced wave intensities as it penetrates deep into droplet from the ambient gas. Droplet surface temperature exhibits smaller fluctuation than that of the ambient gas, and it exhibits a time lag with regard to the pressure variation. Furthermore, the mechanism leading to phase lag of vaporization rate with respect to pressure oscillation was unraveled. Results show that this phase lag varies during the droplet lifetime and it is strongly influenced by oscillation frequency, indicating droplet vaporization is only capable of driving combustion instability in some certain frequency domains. Instead, the amplitude of the oscillation does not have very significant effects. It is noteworthy that thermal inertia of the droplet also plays a considerable role in determining the phase lag.

  9. Water vapor pressure versus environmental lapse rate near the tropopause (United States)

    Ferreira, Antonio; Castanheira, Jose; Gimeno, Luis


    The relationship between water vapor pressure and temperature lapse rate in the vicinity of the tropopause was investigated using in situ observations. The water vapor partial pressures and the lapse rates within a vertical distance of ±1.5 km around the first thermal tropopause were calculated from the vertical soundings conducted by the NOAA/CMDL at several locations in the last few decades (GMD Data Archive). A positive non-linear relationship between the two quantities was found to hold across the studied tropopause region at mid-latitudes and polar latitudes. A similar analysis was performed on the 300 and 250 hPa pressure levels (which often intercept the tropopause region), by collecting temperature and humidity observations within 1979-2008 from the Integrated Global Radiosonde Archive (IGRA). A relationship having almost the same shape was detected for statically stable lapse rates at all latitude zones. Given the relevance of water vapor in the radiative transfer in the upper troposphere, the results are an indication of a local influence of water vapor on the thermal structure of the transition layer between the troposphere and stratosphere

  10. Chemical Vapor Deposition at High Pressure in a Microgravity Environment (United States)

    McCall, Sonya; Bachmann, Klaus; LeSure, Stacie; Sukidi, Nkadi; Wang, Fuchao


    In this paper we present an evaluation of critical requirements of organometallic chemical vapor deposition (OMCVD) at elevated pressure for a channel flow reactor in a microgravity environment. The objective of using high pressure is to maintain single-phase surface composition for materials that have high thermal decomposition pressure at their optimum growth temperature. Access to microgravity is needed to maintain conditions of laminar flow, which is essential for process analysis. Based on ground based observations we present an optimized reactor design for OMCVD at high pressure and reduced gravity. Also, we discuss non-intrusive real-time optical monitoring of flow dynamics coupled to homogeneous gas phase reactions, transport and surface processes. While suborbital flights may suffice for studies of initial stages of heteroepitaxy experiments in space are essential for a complete evaluation of steady-state growth.

  11. Velocity of sound measurements in gaseous per-fluorocarbons and their custom mixtures

    CERN Document Server

    Vacek, V; Lindsay, S


    An inexpensive sonar instrument was prepared for measurements of sound velocity in two fluorocarbon vapors; per-fluoro-n-propane (C3F8), per-fluoro-n-butane (C4F10), and their custom mixtures. The apparatus, measurement principle and instrument software are described. All sound velocity measurements in per-fluorocarbons were made in the low pressure range between 0.01 and 0.4 MPa, and at temperatures between 253 and 303 K. The purity of the C3F8 and C4F10 samples was checked using gas chromatography. Uncertainties in the speed of sound measurements were better than ± 0.1 %. Comparisons were made with theoretical predictions of sound velocity for the two individual components. The instrument was then used for concentration monitoring of custom C3F8/C4F10 mixtures.

  12. Measuring Vapor Pressure with an Isoteniscope: A Hands-on Introduction to Thermodynamic Concepts (United States)

    Chen, Wenqian; Haslam, Andrew J.; Macey, Andrew; Shah, Umang V.; Brechtelsbauer, Clemens


    Characterization of the vapor pressure of a volatile liquid or azeotropic mixture, and its fluid phase diagram, can be achieved with an isoteniscope and an industrial grade digital pressure sensor using the experimental method reported in this study. We describe vapor-pressure measurements of acetone and n-hexane and their azeotrope, and how the…

  13. Apparatus to measure the vapor pressure of slowly decomposing compounds from 1 Pa to 105 Pa


    Berg, Robert F.


    This article describes an apparatus and method for measuring vapor pressures in the range from 1 Pa to 105 Pa. Its three distinctive elements are : (1) the static pressure measurements were made with only a small temperature difference between the vapor and the condensed phase, (2) the sample was degassed in situ, and (3) the temperature range extended up to 200 °C. The apparatus was designed to measure metal-organic precursors, which often are toxic, pyrophoric, or unstable. Vapor pressures ...

  14. Melt-vapor phase transition in the lead-selenium system at atmospheric and low pressure (United States)

    Volodin, V. N.; Burabaeva, N. M.; Trebukhov, S. A.


    The boiling temperature and the corresponding vapor phase composition in the existence domain of liquid solutions were calculated from the partial pressures of saturated vapor of the components and lead selenide over liquid melts in the lead-selenium system. The phase diagram was complemented with the liquid-vapor phase transition at atmospheric pressure and in vacuum of 100 Pa, which allowed us to judge the behavior of the components during the distillation separation.

  15. Analysis of crude oil vapor pressures at the U.S. Strategic Petroleum Reserve.

    Energy Technology Data Exchange (ETDEWEB)

    Rudeen, David Keith (GRAM, Inc., Albuquerque, NM); Lord, David L.


    Crude oil storage caverns at the U.S. Strategic Petroleum Reserve (SPR) are solution-mined from subsurface salt domes along the U.S. Gulf Coast. While these salt domes exhibit many attractive characteristics for large-volume, long-term storage of oil such as low cost for construction, low permeability for effective fluids containment, and secure location deep underground, they also present unique technical challenges for maintaining oil quality within delivery standards. The vapor pressures of the crude oils stored at SPR tend to increase with storage time due to the combined effects of geothermal heating and gas intrusion from the surrounding salt. This presents a problem for oil delivery offsite because high vapor-pressure oil may lead to excessive atmospheric emissions of hydrocarbon gases that present explosion hazards, health hazards, and handling problems at atmospheric pressure. Recognizing this potential hazard, the U.S. Department of Energy, owner and operator of the SPR, implemented a crude oil vapor pressure monitoring program that collects vapor pressure data for all the storage caverns. From these data, DOE evaluates the rate of change in vapor pressures of its oils in the SPR. Moreover, DOE implemented a vapor pressure mitigation program in which the oils are degassed periodically and will be cooled immediately prior to delivery in order to reduce the vapor pressure to safe handling levels. The work described in this report evaluates the entire database since its origin in 1993, and determines the current levels of vapor pressure around the SPR, as well as the rate of change for purposes of optimizing both the mitigation program and meeting safe delivery standards. Generally, the rate of vapor pressure increase appears to be lower in this analysis than reported in the past and, problematic gas intrusion seems to be limited to just a few caverns. This being said, much of the current SPR inventory exceeds vapor pressure delivery guidelines and must be

  16. U.S. Strategic Petroleum Reserve Vapor Pressure Committee 2009 annual report.

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Ray (Allen Energy Services, Inc., Longview, TX); Eldredge, Lisa (DynMcDermott Petroleum Operations, Harahan, LA); DeLuca, Charles (DynMcDermott Petroleum Operations, Harahan, LA); Mihalik, Patrick (DynMcDermott Petroleum Operations, Harahan, LA); Maldonado, Julio (U.S. Department of Energy, Harahan, LA); Lord, David L.; Rudeen, David Keith (GRAM, Inc., Albuquerque, NM); Berndsen, Gerard (U.S. Department of Energy, Harahan, LA)


    This report comprises an annual summary of activities under the U.S. Strategic Petroleum Reserve (SPR) Vapor Pressure Committee in FY2009. The committee provides guidance to senior project management on the issues of crude oil vapor pressure monitoring nd mitigation. The principal objectives of the vapor pressure program are, in the event of an SPR drawdown, to minimize the impact on the environment and assure worker safety and public health from crude oil vapor emissions. The annual report reviews key program areas ncluding monitoring program status, mitigation program status, new developments in measurements and modeling, and path forward including specific recommendations on cavern sampling for the next year. The contents of this report were first presented to SPR senior anagement in December 2009, in a deliverable from the vapor pressure committee. The current SAND report is an adaptation for the Sandia technical audience.

  17. An Inexpensive Microscale Method for Measuring Vapor Pressure, Associated Thermodynamic Variables, and Molecular Weight (United States)

    Demuro, Jason C.; Margarian, Hovanes; Mkhikian, Artavan; No, Kwang Hi; Peterson, Andrew R.


    Existing methods for measuring vapor pressure are too expensive or not quantitative enough for chemistry classes in secondary schools. Our method measures the vapor pressure inside a bubble trapped in a graduated microtube made from a disposable 1-mL glass pipet. Vapor pressures of water, methanol, and ethanol are measured over temperature ranges of 4-90 °C. The enthalpy and entropy of vaporization and boiling points, calculated using the Clausius-Clapeyron equation, agree well with published values. The vapor pressures of aqueous solutions of ethanol and methanol plotted against mole fractions of water give positive deviations from Raoult's law, but concentrations were identified from which molecular weights of the alcohols could be calculated. These molecular weights are not significantly different from published values. Sources of error in the method are analyzed. A procedure for use in secondary schools is outlined.

  18. Reappraisal of disparities between osmolality estimates by freezing point depression and vapor pressure deficit methods. (United States)

    Winzor, Donald J


    As a response to recent expression of concern about possible unreliability of vapor pressure deficit measurements (K. Kiyosawa, Biophys. Chem. 104 (2003) 171-188), the results of published studies on the temperature dependence of the osmotic pressure of aqueous polyethylene glycol solutions are shown to account for the observed discrepancies between osmolality estimates obtained by freezing point depression and vapor pressure deficit osmometry--the cause of the concern.

  19. Numerical Analyses and Forecasting of Surface Air Temperature and Water Vapor Pressure. (United States)

    Analyses and forecasting of heat exchange, fog probability and visibility over the oceans and a number of other numerical environmental analyses/forecasts require a detailed analysis and forecasting of surface air vapor pressure and temperature. Based on earlier encouraging studies by a few Norwegian researchers, such response computation and numerical analysis/forecasting of surface air vapor pressure and temperature is outlined. It is shown that the changes of surface air properties, and sea- air temperature and vapor pressure differences are mainly determined by

  20. Apparatus to measure the vapor pressure of slowly decomposing compounds from 1 Pa to 105 Pa (United States)

    Berg, Robert F.


    This article describes an apparatus and method for measuring vapor pressures in the range from 1 Pa to 105 Pa. Its three distinctive elements are : (1) the static pressure measurements were made with only a small temperature difference between the vapor and the condensed phase, (2) the sample was degassed in situ, and (3) the temperature range extended up to 200 °C. The apparatus was designed to measure metal-organic precursors, which often are toxic, pyrophoric, or unstable. Vapor pressures are presented for naphthalene, ferrocene, diethyl phthalate, and TEMAH (tetrakisethylmethylaminohafnium). Also presented are data for the temperature-dependent decomposition rate of TEMAH. PMID:27274567

  1. Prediction of vapor pressure and heats of vaporization of edible oil/fat compounds by group contribution

    DEFF Research Database (Denmark)

    Ceriani, Roberta; Gani, Rafiqul; Liu, Y.A.


    In the present work, a group contribution method is proposed for the estimation of vapor pressures and heats of vaporization of organic liquids found in edible fat/oil and biofuel industries as a function of temperature. The regression of group contribution parameters was based on an extensive...... databank (2036 values) composed by fatty compounds, i.e., fatty acids, methyl-, ethyl-, propyl- and butyl- esters, fatty alcohols, tri-, di- and monoacylglycerols and hydrocarbons. This new methodology gives improved predictions when compared to a prior group contribution equation (Ceriani and Meirelles...

  2. New expressions to describe solution nonideal osmotic pressure, freezing point depression, and vapor pressure. (United States)

    Fullerton, G D; Zimmerman, R J; Cantu, C; Cameron, I L


    New empirical expressions for osmotic pressure, freezing point depression, and vapor pressure are proposed based on the concepts of volume occupancy and (or) hydration force. These expressions are in general inverse relationships in comparison to the standard ideal expressions for the same properties. The slopes of the new equations are determined by the molecular weight of the solute and known constants. The accuracy and precision of the molecular weights calculated from the slope are identical and approximately 1% for the experiments reported here. The nonideality of all three colligative expressions is described by a dimensionless constant called the solute-solvent interaction parameter I. The results on sucrose have the same I = 0.26 for all three solution properties. The nonideality parameter I increased from 0.26 on sucrose to 1.7 on hemoglobin to successfully describe the well-known nonideal response of macromolecules.

  3. Modeling chemical vapor deposition of silicon dioxide in microreactors at atmospheric pressure

    NARCIS (Netherlands)

    Konakov, S.A.; Krzhizhanovskaya, V.V.


    We developed a multiphysics mathematical model for simulation of silicon dioxide Chemical Vapor Deposition (CVD) from tetraethyl orthosilicate (TEOS) and oxygen mixture in a microreactor at atmospheric pressure. Microfluidics is a promising technology with numerous applications in chemical synthesis

  4. Indoor/outdoor connections exemplified by processes that depend on an organic compound's saturation vapor pressure

    DEFF Research Database (Denmark)

    Weschler, Charles J.


    Outdoor and indoor environments are profitably viewed as parts of a whole connected through various physical and chemical interactions. This paper examines four phenomena that share a dependence on vapor pressure-the extent to which an organic compound in the gas phase sorbs on airborne particles...... first estimates of the above processes. For typical indoor conditions, only larger compounds with lower-saturation vapor pressures (e.g., tetracosane, pentacosane, or di-2-ethylhexyl phthalate) have airborne particle concentrations comparable to or larger than gas phase concentrations. Regardless......'s saturation vapor pressure correlates in a linear fashion with the logarithms of equilibrium coefficients characteristic of each of these four phenomena. Since, to a rough approximation, the log of an organic compound's vapor pressure scales with its molecular weight, molecular weight can be used to make...

  5. Liquid-propellant droplet vaporization and combustion in high pressure environments (United States)

    Yang, Vigor


    In order to correct the deficiencies of existing models for high-pressure droplet vaporization and combustion, a fundamental investigation into this matter is essential. The objective of this research are: (1) to acquire basic understanding of physical and chemical mechanisms involved in the vaporization and combustion of isolated liquid-propellant droplets in both stagnant and forced-convective environments; (2) to establish droplet vaporization and combustion correlations for the study of liquid-propellant spray combustion and two-phase flowfields in rocket motors; and (3) to investigate the dynamic responses of multicomponent droplet vaporization and combustion to ambient flow oscillations.

  6. Effects of altitude on transpiration, leaf vapor pressure deficit and leaf water potential in oriental beech

    Directory of Open Access Journals (Sweden)

    Fatih Bayraktar


    Full Text Available This study was designed to determine the effect of altitude on transpiration, leaf vapor pressure deficit and leaf water potential in oriental beech (Fagus orientalis Lipsky. The study area was located in Ortaköy, Artvin, and the experimental area had the same soil structure and aspect. The study showed that transpiration and leaf vapor pressure deficit increased but leaf water potential decreased by altitudinal gradient

  7. New Micro-Method for Prediction of Vapor Pressure of Energetic Materials (United States)


    temperatures for 14 compounds (mix of energetic and non-energetic materials). References for vapor pressures: TNT, urea nitrate , PETN, RDX, HMX, TATB...standard Melamine Sigma Aldrich Urea Nitrate Matt Sherrill (U.S. Army Research Laboratory [ARL]) RDX Class 5; Lot HOL88M675079 HMX Class 5; Lot...energetic materials). References for vapor pressures: TNT, urea nitrate , PETN, RDX, HMX, TATB, and HNS (20), caffeine (19, 21 both values used in linear

  8. Phase change events of volatile liquid perfluorocarbon contrast agents produce unique acoustic signatures. (United States)

    Sheeran, Paul S; Matsunaga, Terry O; Dayton, Paul A


    Phase-change contrast agents (PCCAs) provide a dynamic platform to approach problems in medical ultrasound (US). Upon US-mediated activation, the liquid core vaporizes and expands to produce a gas bubble ideal for US imaging and therapy. In this study, we demonstrate through high-speed video microscopy and US interrogation that PCCAs composed of highly volatile perfluorocarbons (PFCs) exhibit unique acoustic behavior that can be detected and differentiated from standard microbubble contrast agents. Experimental results show that when activated with short pulses PCCAs will over-expand and undergo unforced radial oscillation while settling to a final bubble diameter. The size-dependent oscillation phenomenon generates a unique acoustic signal that can be passively detected in both time and frequency domain using confocal piston transducers with an 'activate high' (8 MHz, 2 cycles), 'listen low' (1 MHz) scheme. Results show that the magnitude of the acoustic 'signature' increases as PFC boiling point decreases. By using a band-limited spectral processing technique, the droplet signals can be isolated from controls and used to build experimental relationships between concentration and vaporization pressure. The techniques shown here may be useful for physical studies as well as development of droplet-specific imaging techniques.

  9. Acoustic and photoacoustic characterization of micron-sized perfluorocarbon emulsions. (United States)

    Strohm, Eric M; Gorelikov, Ivan; Matsuura, Naomi; Kolios, Michael C


    Perfluorocarbon droplets containing nanoparticles (NPs) have recently been investigated as theranostic and dual-mode contrast agents. These droplets can be vaporized via laser irradiation or used as photoacoustic contrast agents below the vaporization threshold. This study investigates the photoacoustic mechanism of NP-loaded droplets using photoacoustic frequencies between 100 and 1000 MHz, where distinct spectral features are observed that are related to the droplet composition. The measured photoacoustic spectrum from NP-loaded perfluorocarbon droplets was compared to a theoretical model that assumes a homogenous liquid. Good agreement in the location of the spectral features was observed, which suggests the NPs act primarily as optical absorbers to induce thermal expansion of the droplet as a single homogenous object. The NP size and composition do not affect the photoacoustic spectrum; therefore, the photoacoustic signal can be maximized by optimizing the NP optical absorbing properties. To confirm the theoretical parameters in the model, photoacoustic, ultrasonic, and optical methods were used to estimate the droplet diameter. Photoacoustic and ultrasonic methods agreed to within 1.4%, while the optical measurement was 8.5% higher; this difference decreased with increasing droplet size. The small discrepancy may be attributed to the difficulty in observing the small droplets through the partially translucent phantom.

  10. Distribution of Vapor Pressure in the Vacuum Freeze-Drying Equipment

    Directory of Open Access Journals (Sweden)

    Shiwei Zhang


    Full Text Available In the big vacuum freeze-drying equipment, the drying rate of materials is uneven at different positions. This phenomenon can be explained by the uneven distribution of vapor pressure in chamber during the freeze-drying process. In this paper, a mathematical model is developed to describe the vapor flow in the passageways either between material plates and in the channel between plate groups. The distribution of vapor pressure along flow passageway is given. Two characteristic factors of passageways are defined to express the effects of structural and process parameters on vapor pressure distribution. The affecting factors and their actions are quantitatively discussed in detail. Two examples are calculated and analyzed. The analysis method and the conclusions are useful to estimate the difference of material drying rate at different parts in equipment and to direct the choice of structural and process parameters.

  11. Integrated Rig for the Production of Boron Nitride Nanotubes via the Pressurized Vapor-Condenser Method (United States)

    Smith, Michael W. (Inventor); Jordan, Kevin C. (Inventor)


    An integrated production apparatus for production of boron nitride nanotubes via the pressure vapor-condenser method. The apparatus comprises: a pressurized reaction chamber containing a continuously fed boron containing target having a boron target tip, a source of pressurized nitrogen and a moving belt condenser apparatus; a hutch chamber proximate the pressurized reaction chamber containing a target feed system and a laser beam and optics.

  12. Surfactant and perfluorocarbon aerosolization during different mechanical ventilation strategies by means of inhalation catheters: an in vitro study. (United States)

    Murgia, Xabier; Gastiasoro, Elena; Mielgo, Victoria; Ruiz-Del-Yerro, Estibaliz; Alvarez-Diaz, Francisco José; Lafuente, Hector; Valls-I-Soler, Adolf; Gomez-Solaetxe, Miguel Angel; Rey-Santano, Carmen


    Aerosol delivery of surfactant and perfluorocarbon (PFC) is a desirable therapeutic approach for the treatment of various lung diseases in patients undergoing mechanical ventilation. However, the behavior of these substances during aerosolization differs significantly from that of aqueous solutions. In particular, the high vapor pressure of many PFCs tends to result in greater evaporation during mechanical ventilation. Three PFCs and surfactant were aerosolized during mechanical ventilation by means of three intratracheal inhalation catheters (IC) with different air flow rates (IC-1.23, IC-1.1, and IC-1.4), with their aerosol generating tip placed at the distal end of the endotracheal tube (i.d. 4 mm). The influence of four different ventilation strategies on aerosol production rate and PFC and surfactant recovery was studied. The changes in intrapulmonary pressure produced by the air jets of each IC were measured. With IC-1.23 and IC-1.1, the highest rates of aerosol production were achieved using FC75 (2.27±0.18 and 0.76±0.01, respectively) followed by PFOB (1.74±0.06 and 0.56±0.04), PFD (0.82±0.01 and 0.21±0.01), and surfactant (0.42±0.05 and 0.092±0.01). With IC-1.4 modest aerosol production was obtained irrespective of the aerosolized compound. Mechanical ventilation influenced aerosol recovery, with the trend being toward recovering higher percentages of the compounds with lower peak inspiratory pressure (PIP) and lower respiratory rate (RR) settings. The highest percentages of the initial volume were recovered with IC-1.23 (between 65.43%±4.2 FC75 and 90.21%±4.71 surfactant) followed by IC-1.1 (between 46.48%±4.46 FC75 and 73.19%±2.82 PFOB) and IC-1.4 (between 4.65%±4.36 FC75 and 63.24%±9.71 surfactant). Each of three of the ICs were found to increase the intrapulmonary pressure by about 2-3 cmH₂O during mechanical ventilation. Despite of mechanical ventilation, IC-1.23 and IC-1.1 were able to deliver significant amounts of surfactant and

  13. Prediction of the liquid-vapor equilibrium pressure using the quasi-Gaussian entropy theory

    NARCIS (Netherlands)

    Amadei, A; Roccatano, D; Apol, M.E F; Berendsen, H.J.C.; Di Nola, A.


    We derived a method to evaluate the liquid-vapor equilibrium pressure, with high accuracy over a large range of temperature, using the quasi-Gaussian entropy theory. The final expression that we obtain for the equilibrium pressure as a function of the temperature can be considered as a very accurate

  14. Economic feasibility of replacing sodium vapor and high pressure mercury vapor bulbs with LEDs for street lighting

    Directory of Open Access Journals (Sweden)

    Olusola Olorunfemi Bamisile


    Full Text Available The main aim of this article is to examine the feasibility of an energy audit program. LEDs are used to replace the sodium vapor lamps and high-pressured mercury vapor lamps that are currently used for the street lighting system in the Turkish Republic of Northern Cyprus. 44% of the fossil fuels imported into the Turkish Republic of Northern Cyprus is used for electricity generation, which makes the reduction in the consumption of electicity very important. This project will save as much as 36,880,410 kWh on site annually and 111,758,818 kWh from the source. The economic, environmental, and fossil fuels savings of this project are also evaluated.

  15. Vapor pressures of substituted polycarboxylic acids are much lower than previously reported

    Directory of Open Access Journals (Sweden)

    A. J. Huisman


    Full Text Available The partitioning of compounds between the aerosol and gas phase is a primary focus in the study of the formation and fate of secondary organic aerosol. We present measurements of the vapor pressure of 2-methylmalonic (isosuccinic acid, 2-hydroxymalonic (tartronic acid, 2-methylglutaric acid, 3-hydroxy-3-carboxy-glutaric (citric acid and DL-2,3-dihydroxysuccinic (DL-tartaric acid, which were obtained from the evaporation rate of supersaturated liquid particles levitated in an electrodynamic balance. Our measurements indicate that the pure component liquid vapor pressures at 298.15 K for tartronic, citric and tartaric acids are much lower than the same quantity that was derived from solid state measurements in the only other room temperature measurement of these materials (made by Booth et al., 2010. This strongly suggests that empirical correction terms in a recent vapor pressure estimation model to account for the inexplicably high vapor pressures of these and similar compounds should be revisited, and that due caution should be used when the estimated vapor pressures of these and similar compounds are used as inputs for other studies.

  16. Application of quantitative structure-property relationship analysis to estimate the vapor pressure of pesticides. (United States)

    Goodarzi, Mohammad; Coelho, Leandro dos Santos; Honarparvar, Bahareh; Ortiz, Erlinda V; Duchowicz, Pablo R


    The application of molecular descriptors in describing Quantitative Structure Property Relationships (QSPR) for the estimation of vapor pressure (VP) of pesticides is of ongoing interest. In this study, QSPR models were developed using multiple linear regression (MLR) methods to predict the vapor pressure values of 162 pesticides. Several feature selection methods, namely the replacement method (RM), genetic algorithms (GA), stepwise regression (SR) and forward selection (FS), were used to select the most relevant molecular descriptors from a pool of variables. The optimum subset of molecular descriptors was used to build a QSPR model to estimate the vapor pressures of the selected pesticides. The Replacement Method improved the predictive ability of vapor pressures and was more reliable for the feature selection of these selected pesticides. The results provided satisfactory MLR models that had a satisfactory predictive ability, and will be important for predicting vapor pressure values for compounds with unknown values. This study may open new opportunities for designing and developing new pesticide. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Low-Pressure Chemical Vapor (LPCVD) Graphene Growth Study and Raman Characterization (United States)


    films deposited for a growth study is discussed. Low pressure chemical vapor deposition was utilized to grow graphene layers onto copper foil substrates...exfoliation method (3); however, recent efforts have focused on graphene synthesis by conventional methods, such as chemical vapor deposition ( CVD ) and...ultrahigh vacuum, high temperature annealing (i.e., epitaxial graphene from SiC) (4, 5). CVD , in particular, is a promising growth technique because

  18. Methods of Generating Submicrometer Phase-Shift Perfluorocarbon Droplets for Applications in Medical Ultrasonography. (United States)

    Sheeran, Paul S; Matsuura, Naomi; Borden, Mark A; Williams, Ross; Matsunaga, Terry O; Burns, Peter N; Dayton, Paul A


    Continued advances in the field of ultrasound and ultrasound contrast agents have created new approaches to imaging and medical intervention. Phase-shift perfluorocarbon droplets, which can be vaporized by ultrasound energy to transition from the liquid to the vapor state, are one of the most highly researched alternatives to clinical ultrasound contrast agents (i.e., microbubbles). In this paper, part of a special issue on methods in biomedical ultrasonics, we survey current techniques to prepare ultrasound-activated nanoscale phase-shift perfluorocarbon droplets, including sonication, extrusion, homogenization, microfluidics, and microbubble condensation. We provide example protocols and discuss advantages and limitations of each approach. Finally, we discuss best practice in characterization of this class of contrast agents with respect to size distribution and ultrasound activation.

  19. Pressure-coupled vaporization and combustion responses of liquid-fuel droplets in high-pressure environments (United States)

    Yang, Vigor; Shuen, J. S.; Hsiao, C. C.


    The dynamic responses of liquid-fuel droplet vaporization and combustion to ambient pressure oscillations are examined. The analysis is based on the complete sets of conservation equations for both gas and liquid phases, and accommodates detailed treatments of finite-rate chemical kinetics and variable properties. With a full account of thermodynamic phase equilibrium at the droplet surface, the model enables a systematic examination of the effects of ambient flow conditions on the droplet behavior. The responses of hydrocarbon fuel droplets in both sub- and super-critical environments are investigated. Results indicate that the droplet gasification and burning mechanisms depend greatly on the ambient pressure. In particular, a rapid enlargement of the vaporization and combustion responses occurs when the droplet surface reaches its critical point, mainly due to the strong variations of latent heat of vaporization and thermophysical properties at the critical state.


    Energy Technology Data Exchange (ETDEWEB)

    Kuhne, W.


    Standard procedures for the measurement of tritium in water samples often require distillation of an appropriate sample aliquot. This distillation process may result in a fractionation of tritiated water and regular light water due to the vapor pressure isotope effect, introducing either a bias or an additional contribution to the total tritium measurement uncertainty. The magnitude of the vapor pressure isotope effect is characterized as functions of the amount of water distilled from the sample aliquot and the heat settings for the distillation process. The tritium concentration in the distillate is higher than the tritium concentration in the sample early in the distillation process, it then sharply decreases due to the vapor pressure isotope effect and becomes lower than the tritium concentration in the sample, until the high tritium concentration retained in the boiling flask is evaporated at the end of the process. At that time, the tritium concentration in the distillate again overestimates the sample tritium concentration. The vapor pressure isotope effect is more pronounced the slower the evaporation and distillation process is conducted; a lower heat setting during the evaporation of the sample results in a larger bias in the tritium measurement. The experimental setup used and the fact that the current study allowed for an investigation of the relative change in vapor pressure isotope effect in the course of the distillation process distinguish it from and extend previously published measurements. The separation factor as a quantitative measure of the vapor pressure isotope effect is found to assume values of 1.034 {+-} 0.033, 1.052 {+-} 0.025, and 1.066 {+-} 0.037, depending on the vigor of the boiling process during distillation of the sample. A lower heat setting in the experimental setup, and therefore a less vigorous boiling process, results in a larger value for the separation factor. For a tritium measurement in water samples, this implies that

  1. Growth of a dry spot under a vapor bubble at high heat flux and high pressure

    CERN Document Server

    Nikolayev, Vadim; Lagier, G -L; Hegseth, J


    We report a 2D modeling of the thermal diffusion-controlled growth of a vapor bubble attached to a heating surface during saturated boiling. The heat conduction problem is solved in a liquid that surrounds a bubble with a free boundary and in a semi-infinite solid heater by the boundary element method. At high system pressure the bubble is assumed to grow slowly, its shape being defined by the surface tension and the vapor recoil force, a force coming from the liquid evaporating into the bubble. It is shown that at some typical time the dry spot under the bubble begins to grow rapidly under the action of the vapor recoil. Such a bubble can eventually spread into a vapor film that can separate the liquid from the heater thus triggering the boiling crisis (critical heat flux).

  2. Laser irradiated fluorescent perfluorocarbon microparticles in 2-D and 3-D breast cancer cell models (United States)

    Niu, Chengcheng; Wang, Long; Wang, Zhigang; Xu, Yan; Hu, Yihe; Peng, Qinghai


    Perfluorocarbon (PFC) droplets were studied as new generation ultrasound contrast agents via acoustic or optical droplet vaporization (ADV or ODV). Little is known about the ODV irradiated vaporization mechanisms of PFC-microparticle complexs and the stability of the new bubbles produced. In this study, fluorescent perfluorohexane (PFH) poly(lactic-co-glycolic acid) (PLGA) particles were used as a model to study the process of particle vaporization and bubble stability following excitation in two-dimensional (2-D) and three-dimensional (3-D) cell models. We observed localization of the fluorescent agent on the microparticle coating material initially and after vaporization under fluorescence microscopy. Furthermore, the stability and growth dynamics of the newly created bubbles were observed for 11 min following vaporization. The particles were co-cultured with 2-D cells to form 3-D spheroids and could be vaporized even when encapsulated within the spheroids via laser irradiation, which provides an effective basis for further work.

  3. Theoretical and experimental studies on freezing point depression and vapor pressure deficit as methods to measure osmotic pressure of aqueous polyethylene glycol and bovine serum albumin solutions. (United States)

    Kiyosawa, Keitaro


    For survival in adverse environments where there is drought, high salt concentration or low temperature, some plants seem to be able to synthesize biochemical compounds, including proteins, in response to changes in water activity or osmotic pressure. Measurement of the water activity or osmotic pressure of simple aqueous solutions has been based on freezing point depression or vapor pressure deficit. Measurement of the osmotic pressure of plants under water stress has been mainly based on vapor pressure deficit. However, differences have been noted for osmotic pressure values of aqueous polyethylene glycol (PEG) solutions measured by freezing point depression and vapor pressure deficit. For this paper, the physicochemical basis of freezing point depression and vapor pressure deficit were first examined theoretically and then, the osmotic pressure of aqueous ethylene glycol and of PEG solutions were measured by both freezing point depression and vapor pressure deficit in comparison with other aqueous solutions such as NaCl, KCl, CaCl(2), glucose, sucrose, raffinose, and bovine serum albumin (BSA) solutions. The results showed that: (1) freezing point depression and vapor pressure deficit share theoretically the same physicochemical basis; (2) theoretically, they are proportional to the molal concentration of the aqueous solutions to be measured; (3) in practice, the osmotic pressure levels of aqueous NaCl, KCl, CaCl(2), glucose, sucrose, and raffinose solutions increase in proportion to their molal concentrations and there is little inconsistency between those measured by freezing point depression and vapor pressure deficit; (4) the osmotic pressure levels of aqueous ethylene glycol and PEG solutions measured by freezing point depression differed from the values measured by vapor pressure deficit; (5) the osmotic pressure of aqueous BSA solution measured by freezing point depression differed slightly from that measured by vapor pressure deficit.

  4. Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, April 1, 1996--June 30, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Suuberg, E.M.; Oja, V.; Lilly, W.D.


    As the world continues to deplete its petroleum reserves, then heavy crude oil, coal liquids, and other heavy fossil fuels may be required to meet the world energy needs. Heavy fossil fuels contain molecules that are large and more aromatic and that contain more heteroatoms than those found in liquid crude oil. There is also significant current interest in general area of coal pyrolysis, particularly with respect to comprehensive models of this complicated phenomenon. This interest derives from central role of pyrolysis in all thermally driven coal conversion processes - gasification, combustion, liquefaction, mild gasification, or thermal beneficiation. There remain several key data needs in these application areas. Among them is a need for a more reliable correlation for prediction of the vapor pressures of heavy, primary coal tars. Such information is important in design of all coal conversion processes, in which the volatility of tarry products is of major concern. This paper presents work on the vapor pressures of coal tars using the continuous knudsen effusion technique.

  5. Comparative evaluation of naturally ventilated screenhouse and evaporative cooled greenhouse based on optimal vapor pressure deficit

    NARCIS (Netherlands)

    Shamshiri, Ramin; Ahmad, Desa; Wan Ismail, Wan Ishak; Man, Hasfalin Che; Zakaria, Abd Jamil; Beveren, Van Peter; Yamin, Muhammad


    The objective of this study was to compare two closed-field plant production environments for tomato cultivation based on optimal vapor pressure deficit (VPD). Experiment was carried out in tropical lowlands of Malaysia by collecting 11 days of sample data during March (2014), from an evaporative

  6. The Action of Pressure-Radiation Forces on Pulsating Vapor Bubbles

    NARCIS (Netherlands)

    Hao, Y.; Oguz, H.N.; Prosperetti, Andrea


    The action of pressure-radiation (or Bjerknes) forces on gas bubbles is well understood. This paper studies the analogous phenomenon for vapor bubbles, about which much less is known. A possible practical application is the removal of boiling bubbles from the neighborhood of a heated surface in the

  7. 46 CFR 30.10-59 - Reid vapor pressure-TB/ALL. (United States)


    ... 46 Shipping 1 2010-10-01 2010-10-01 false Reid vapor pressure-TB/ALL. 30.10-59 Section 30.10-59 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Definitions § 30.10... Headquarters for reading purposes or it may be purchased from the Society at 100 Barr Harbor Drive, West...

  8. Vapor Pressure of Hexamethylene Triperoxide Diamine (HTMD) Determined with Secondary Electrospray Ionization Mass Spectrometry (United States)


    rate constant for decomposition of 10-3 sec-1, three orders of magnitude higher than triacetone triperoxide ( TATP , 10-6 sec-1) with trimethylamine... TATP and diacetone diperoxide (DADP)) but only succeeded in assigning an upper limit on the vapor pressure of HMTD (0.04 Pa) [5]. The authors

  9. Atmospheric pressure chemical vapor deposition of ZnO: Process modeling and experiments

    NARCIS (Netherlands)

    Deelen, J. van; Illiberi, A.; Kniknie, B.; Beckers, E.H.A.; Simons, P.J.P.M.; Lankhorst, A.


    The deposition of zinc oxide has been performed by atmospheric pressure chemical vapor deposition and trends in growth rates are compared with the literature. Diethylzinc and tertiary butanol were used as the primary reactants and deposition rates above 800 nm/min were obtained. The reaction

  10. Atmospheric pressure chemical vapor deposition of ZnO: Process modeling and experiments

    NARCIS (Netherlands)

    Deelen, J. van; Illiberi, A.; Kniknie, B.; Beckers, E.H.A.; Simons, P.J.P.M.; Lankhorst, A.


    The deposition of zinc oxide has been performed by atmospheric pressure chemical vapor deposition and trends in growth rates are compared with the literature. Diethylzinc and tertiary butanol were used as the primary reactants and deposition rates above 800 nm/minwere obtained. The reaction

  11. Development of a quasi-adiabatic calorimeter for the determination of the water vapor pressure curve. (United States)

    Mokdad, S; Georgin, E; Hermier, Y; Sparasci, F; Himbert, M


    Progress in the knowledge of the water saturation curve is required to improve the accuracy of the calibrations in humidity. In order to achieve this objective, the LNE-CETIAT and the LNE-CNAM have jointly built a facility dedicated to the measurement of the saturation vapor pressure and temperature of pure water. The principle is based on a static measurement of the pressure and the temperature of pure water in a closed, temperature-controlled thermostat, conceived like a quasi-adiabatic calorimeter. A copper cell containing pure water is placed inside a temperature-controlled copper shield, which is mounted in a vacuum-tight stainless steel vessel immersed in a thermostated bath. The temperature of the cell is measured with capsule-type standard platinum resistance thermometers, calibrated with uncertainties below the millikelvin. The vapor pressure is measured by calibrated pressure sensors connected to the cell through a pressure tube whose temperature is monitored at several points. The pressure gauges are installed in a thermostatic apparatus ensuring high stability of the pressure measurement and avoiding any condensation in the tubes. Thanks to the employment of several technical solutions, the thermal contribution to the overall uncertainty budget is reduced, and the remaining major part is mainly due to pressure measurements. This paper presents a full description of this facility and the preliminary results obtained for its characterization.

  12. Vapor pressure data for fatty acids obtained using an adaptation of the DSC technique

    Energy Technology Data Exchange (ETDEWEB)

    Matricarde Falleiro, Rafael M. [LPT, Departamento de Processos Quimicos (DPQ), Faculdade de Engenharia Quimica, Universidade de Campinas (UNICAMP), 13083-852 Campinas - SP (Brazil); Akisawa Silva, Luciana Y. [Departamento de Ciencias Exatas e da Terra, Universidade Federal de Sao Paulo (UNIFESP), 09972-270 Diadema - SP (Brazil); Meirelles, Antonio J.A. [EXTRAE, Departamento de Engenharia de Alimentos (DEA), Faculdade de Engenharia de Alimentos, Universidade de Campinas (UNICAMP), 13083-862 Campinas - SP (Brazil); Kraehenbuehl, Maria A., E-mail: [LPT, Departamento de Processos Quimicos (DPQ), Faculdade de Engenharia Quimica, Universidade de Campinas (UNICAMP), 13083-852 Campinas - SP (Brazil)


    Highlights: Black-Right-Pointing-Pointer Vapor pressure data of fatty acids were measured by Differential Scanning Calorimetry. Black-Right-Pointing-Pointer The DSC technique is especially advantageous for expensive chemicals. Black-Right-Pointing-Pointer High heating rate was used for measuring the vapor pressure data. Black-Right-Pointing-Pointer Antoine constants were obtained for the selected fatty acids. - Abstract: The vapor pressure data for lauric (C{sub 12:0}), myristic (C{sub 14:0}), palmitic (C{sub 16:0}), stearic (C{sub 18:0}) and oleic (C{sub 18:1}) acids were obtained using Differential Scanning Calorimetry (DSC). The adjustments made in the experimental procedure included the use of a small sphere (tungsten carbide) placed over the pinhole of the crucible (diameter of 0.8 mm), making it possible to use a faster heating rate than that of the standard method and reducing the experimental time. The measurements were made in the pressure range from 1333 to 9333 Pa, using small sample quantities of fatty acids (3-5 mg) at a heating rate of 25 K min{sup -1}. The results showed the effectiveness of the technique under study, as evidenced by the low temperature deviations in relation to the data reported in the literature. The Antoine constants were fitted to the experimental data whose values are shown in Table 5.

  13. Observations on vapor pressure in SPR caverns : sources.

    Energy Technology Data Exchange (ETDEWEB)

    Munson, Darrell Eugene


    considered through computations using the Multimechanism Deformation Coupled Fracture (MDCF) model, suggesting a relative minor, but potentially significant, contribution to the regain process. Apparently, gains in gas content can be generated from the oil itself during storage because the salt dome has been heated by the geothermal gradient of the earth. The heated domal salt transfers heat to the oil stored in the caverns and thereby increases the gas released by the volatile components and raises the boiling point pressure of the oil. The process is essentially a variation on the fractionation of oil, where each of the discrete components of the oil have a discrete temperature range over which that component can be volatized and removed from the remaining components. The most volatile components are methane and ethane, the shortest chain hydrocarbons. Since this fractionation is a fundamental aspect of oil behavior, the volatile component can be removed by degassing, potentially prohibiting the evolution of gas at or below the temperature of the degas process. While this process is well understood, the ability to describe the results of degassing and subsequent regain is not. Trends are not well defined for original gas content, regain, and prescribed effects of degassing. As a result, prediction of cavern response is difficult. As a consequence of this current analysis, it is suggested that solutioning brine of the final fluid exchange of a just completed cavern, immediately prior to the first oil filling, should be analyzed for gas content using existing analysis techniques. This would add important information and clarification to the regain process. It is also proposed that the quantity of volatile components, such as methane, be determined before and after any degasification operation.

  14. Pressure dependence of in situ boron-doped silicon films prepared by low-pressure chemical vapor deposition. II. Resistivity (United States)

    Haji, L.; Hamedi, L.; Loisel, B.; Gauneau, M.; Joubert, P.; Sarret, M.


    The effects of silane pressure and temperature on the in situ boron incorporation and resistivity of low-pressure chemical vapor deposited polycrystalline silicon films were studied in the ranges of 2.5×10-3-1 Torr and 515-700 °C. By lowering the silane pressure, the boron concentration increases (up to 1×1022 cm-3) and the resistivity decreases down to about 2×10-3 Ω cm without annealing. For high deposition pressure (≥0.1 Torr), the resistivity decreases as the temperature is lowered. In this latter case the secondary-ion mass spectrometry profiles reveal a boron accumulation at the layer-substrate interface, which is always observed independently of the substrate nature.

  15. Some possible filler alloys with low vapor pressures for refractory-metal brazing (United States)

    Morris, J. F.


    A compilation of eutectics and melting-point minima for binary combinations of metals having vapor pressures below 10 to the minus 10th power torr at 1500 degrees K and .00005 torr at 2000 degree K is presented. These compositions and others near them on their phase diagrams are potential special brazing fillers for refractory metals. Some possible problems and advantages for fusion bonds of such mixtures are indicated. Evaluations of brazing fillers containing refractory metals are reported.

  16. Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, 1 January 1996--31 March 1996

    Energy Technology Data Exchange (ETDEWEB)

    Suuberg, E.M.


    The vapor pressure correlations that exist at present for coal tars are very crude and they are not considered reliable to even an order of magnitude. Sophisticated general correlative approaches are slowly being developed, based upon group contribution methods, or based upon some key functional features of the molecules. These are as yet difficult to apply to coal tars. The detailed group contribution methods, in which fairly precise structural information is needed, do not lend themselves well for application to very complex, poorly characterized coal tars. The methods based upon more global types of characterizations have not yet dealt much with the question of oxygenated functional groups. In short, only very limited correlations exist, and these are not considered reliable to even an order of magnitude when applied to tars. The present project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well- established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal, (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars, (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. A significant amount of time has been devoted during this quarter to developing techniques for measurements of vapor pressures of coal tar related compounds, and mixtures, in a ``continuous`` mode, using the effusion technique.

  17. Apparatus to measure the vapor pressure of slowly decomposing compounds from 1 Pa to 10(5) Pa. (United States)

    Berg, Robert F


    This article describes an apparatus and method for measuring vapor pressures in the range from 1 Pa to 10(5) Pa. Its three distinctive elements are : (1) the static pressure measurements were made with only a small temperature difference between the vapor and the condensed phase, (2) the sample was degassed in situ, and (3) the temperature range extended up to 200 °C. The apparatus was designed to measure metal-organic precursors, which often are toxic, pyrophoric, or unstable. Vapor pressures are presented for naphthalene, ferrocene, diethyl phthalate, and TEMAH (tetrakisethylmethylaminohafnium). Also presented are data for the temperature-dependent decomposition rate of TEMAH.

  18. Vapor pressures and sublimation enthalpies of seven heteroatomic aromatic hydrocarbons measured using the Knudsen effusion technique

    Energy Technology Data Exchange (ETDEWEB)

    Goldfarb, Jillian L., E-mail: [Division of Engineering, Brown University, Providence, RI 02912 (United States); Suuberg, Eric M., E-mail: Eric_Suuberg@brown.ed [Division of Engineering, Brown University, Providence, RI 02912 (United States)


    The vapor pressures of seven heteroatom-containing cyclic aromatic hydrocarbons, ranging in molecular weight from (168.19 to 208.21) g . mol{sup -1} were measured over the temperature range of (301 to 486) K using the isothermal Knudsen effusion technique. The compounds measured include: anthraquinone, 9-fluorenone, 9-fluorenone oxime, phenoxazine, phenoxathiin, and 9H-pyrido[3,4-b]indole. These solid-state sublimation measurements provided values that are compared to vapor pressures of parent aromatic compounds (anthracene and fluorene) and to others with substituent groups in order to examine the effects of alcohol, ketone, pyridine, and pyrrole functionality on this property. The enthalpies and entropies of sublimation for each compound were determined from the Clausius-Clapeyron equation. Though there is no consistent trend in terms of the effects of substitutions on changes in the enthalpy or entropy of sublimation, we note that the prevalence of enthalpic or entropic driving forces on vapor pressure depend on molecule-specific factors and not merely molecular weight of the substituents.

  19. Assessment of Fluctuation Patterns Similarity in Temperature and Vapor Pressure Using Discrete Wavelet Transform

    Directory of Open Access Journals (Sweden)

    A. Araghi


    Full Text Available Period and trend are two main effective and important factors in hydro-climatological time series and because of this importance, different methods have been introduced and applied to study of them, until now. Most of these methods are statistical basis and they are classified in the non-parametric tests. Wavelet transform is a mathematical based powerful method which has been widely used in signal processing and time series analysis in recent years. In this research, trend and main periodic patterns similarity in temperature and vapor pressure has been studied in Babolsar, Tehran and Shahroud synoptic stations during 55 years period (from 1956 to 2010, using wavelet method and the sequential Mann-Kendall trend test. The results show that long term fluctuation patterns in temperature and vapor pressure have more correlations in the arid and semi-arid climates, as well as short term oscillation patterns in temperature and vapor pressure in the humid climates, and these dominant periods increase with the aridity of region.

  20. Oxidation of uranium in low partial pressures of oxygen and water vapor at 100/sup 0/C

    Energy Technology Data Exchange (ETDEWEB)

    Weirick, L J


    Oxygen isotope studies indicate that a previously proposed theory describing the oxidation of uranium is incorrect. This theory had proposed that the uranium reacted directly with water vapor to form uranium dioxide and hydrogen and the hydrogen subsequently reacted with the free oxygen to form water. This study shows that oxygen reacts directly with uranium, the role of water vapor being to affect the uranium oxide structure which is formed. The reaction rate of uranium with water vapor in the absence of oxygen was linear and proportional to the water vapor pressure for water vapor pressures between 2 and 20 Torr. Hydrogen was produced by the reaction at a rate of almost two moles for every one mole of uranium dioxide formed. The oxide was identified as UO/sub 2/ /sub 0/. The reaction of uranium with water vapor in the presence of oxygen showed three separate regions of reaction response. In one region, at low oxygen pressure, the reaction was the same as with no oxygen, a second region at oxygen pressures between 0.05 and 1 Torr was a transition stage and in the third region, at oxygen pressures above 1 Torr, the reaction rate was linear and independent of both oxygen and water vapor pressure. The oxide formed was identified as nominally U/sub 4/O/sub 9/. Only a small amount of hydrogen was produced.

  1. Fast membrane osmometer as alternative to freezing point and vapor pressure osmometry. (United States)

    Grattoni, Alessandro; Canavese, Giancarlo; Montevecchi, Franco Maria; Ferrari, Mauro


    Osmometry is an essential technique for solution analysis and the investigation of chemical and biological phenomena. Commercially available osmometers rely on the measurements of freezing point, vapor pressure, and osmotic pressure of solutions. Although vapor pressure osmometry (VPO) and freezing point osmometry (FPO) can perform rapid and inexpensive measurements, they are indirect techniques, which rely on thermodynamic assumptions, which limit their applicability. While membrane osmometry (MO) provides a potentially unlimited direct measurement of osmotic pressure and solution osmolality, the conventional technique is often time-consuming and difficult to operate. In the present work, a novel membrane osmometer is presented. The instrument significantly reduces the conventional MO measurement time and is not subject to the limitations of VPO and FPO. For this paper, the osmotic pressure of aqueous sucrose solutions was collected in a molality range 0-5.5, by way of demonstration of the new instrument. When compared with data found in the literature, the experimental data were generally in good agreement. However, differences among results from the three techniques were observed.

  2. Pressure dependence of in situ boron-doped silicon films prepared by low-pressure chemical vapor deposition. I. Microstructure (United States)

    Joubert, P.; Sarret, M.; Haji, L.; Hamedi, L.; Loisel, B.


    In situ boron-doped silicon films have been deposited by the low-pressure chemical vapor deposition technique in the pressure and temperature ranges of 1-2.5×10-3 Torr and 515-700 °C, respectively. These films have been investigated by means of x-ray diffraction and transmission electron microscopy in order to study the influence of the silane partial pressure and deposition temperature on the microstructure of the doped films. X-ray experiments combined with gradual etching were performed in order to check the in-depth distribution of the crystallite textures. The microstructure of the boron-doped and undoped polysilicon films are compared.

  3. Two-phase pressure drop during CO{sub 2} vaporization in horizontal smooth minichannels

    Energy Technology Data Exchange (ETDEWEB)

    Pamitran, A.S.; Choi, Kwang-Il [Graduate School, Chonnam National University, San 96-1, Dunduk-Dong, Yeosu, Chonnam 550-749 (Korea); Oh, Jong-Taek [Department of Refrigeration and Air Conditioning Engineering, Chonnam National University, San 96-1, Dunduk-dong, Yeosu, Chonnam 550-749 (Korea); Oh, Hoo-Kyu [Department of Refrigeration and Air Conditioning Engineering, Pukyong National University, 100, Yongdang-dong, Nam-Ku, Busan 608-739 (Korea)


    Pressure drop experiments for a natural refrigerant vaporization of CO{sub 2} were performed in horizontal minichannels. The test section was made of stainless steel tubes with inner diameters of 1.5 mm and 3.0 mm and with lengths of 2000 and 3000 mm. This test section was uniformly heated by applying electric current directly to the tubes. Experiments were performed at inlet saturation temperatures of -10, -5 and 10 C, mass flux ranges from 200 to 600 kg m{sup -2} s{sup -1} and heat flux ranges from 10 to 30 kW m{sup -2}. The current study showed the significant effect of mass flux, tube diameter, and saturation temperature on the pressure drop. The experimental results were compared against 13 existing two-phase pressure drop prediction methods. A new pressure drop prediction method based on the Lockhart-Martinelli method was developed with 9.41% mean deviation. (author)

  4. GOZCARDS Source Data for Water Vapor Monthly Zonal Means on a Geodetic Latitude and Pressure Grid V1.01 (United States)

    National Aeronautics and Space Administration — The GOZCARDS Source Data for Water Vapor Monthly Zonal Averages on a Geodetic Latitude and Pressure Grid product (GozSmlpH2O) contains zonal means and related...

  5. GOZCARDS Merged Data for Water Vapor Monthly Zonal Means on a Geodetic Latitude and Pressure Grid V1.01 (United States)

    National Aeronautics and Space Administration — The GOZCARDS Merged Data for Water Vapor Monthly Zonal Averages on a Geodetic Latitude and Pressure Grid product (GozMmlpH2O) contains zonal means and related...

  6. Functionality of albumin-derived perfluorocarbon-based artificial oxygen carriers in the Langendorff-heart†. (United States)

    Wrobeln, Anna; Schlüter, Klaus D; Linders, Jürgen; Zähres, Manfred; Mayer, Christian; Kirsch, Michael; Ferenz, Katja B


    The aim of this study was to prove whether albumin-derived perfluorocarbon-based nanoparticles (capsules) can operate as a novel artificial oxygen carrier in a rat Langendorff-heart perfusion model. Hearts perfused with capsules showed increased left ventricular pressure and rate pressure product compared to hearts perfused with pure Krebs-Henseleit (KH)-buffer. The capsules prevented the myocardium from functional fail when in their absence a noxious ischemia was observed. Capsules did not change rheological properties of KH-buffer and could repeatedly reload with oxygen. This albumin-derived perfluorocarbon-based artificial oxygen carrier preserved the function of rat hearts due to the transport of oxygen in a satisfactory manner. Because of these positive results, the functionality of the applied capsules should be verified in living animals.

  7. High-pressure (vapor + liquid) equilibria in the (nitrogen + n-heptane) system

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Sanchez, Fernando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)]. E-mail:; Eliosa-Jimenez, Gaudencio [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Silva-Oliver, Guadalupe [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Godinez-Silva, Armando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)


    In this work, new (vapor + liquid) equilibrium data for the (N{sub 2} + n-heptane) system were experimentally measured over a wide temperature range from (313.6 to 523.7) K and pressures up to 50 MPa. A static-analytic apparatus with visual sapphire windows and pneumatic capillary samplers was used in the experimental measurements. Equilibrium phase compositions and (vapor + liquid) equilibrium ratios are reported. The new results were compared with those reported by other authors. The comparison showed that the pressure-composition data reported in this work are less scattered than those determined by others. Hence, the results demonstrate the reliability of the experimental apparatus at high temperatures and pressures. The experimental data were represented with the PR and PC-SAFT equations of state by using one-fluid mixing rules and a single temperature independent interaction parameter. Results of the representation showed that the PC-SAFT equation was superior to the PR equation in correlating the experimental data of the (N{sub 2} + n-heptane) system.

  8. Probabilistic approach: back pressure turbine for geothermal vapor-dominated system (United States)

    Alfandi Ahmad, Angga; Xaverius Guwowijoyo, Fransiscus; Pratama, Heru Berian


    Geothermal bussiness nowadays needs to be accelerated in a way that profit can be obtained as soon as reasonable possible. One of the many ways to do this is by using one of geothermal wellhead generating unit (GWGU), called backpressure turbine. Backpressure turbine can be used in producing electricity as soon as there is productive or rather small-scale productive well existed after finished drilling. In a vapor dominated system, steam fraction in the wellhead capable to produce electricity based on each well productivity immediately. The advantage for using vapor dominated system is reduce brine disposal in the wellhead so it will be a cost benefit in operation. The design and calculation for backpressure turbine will use probablistic approach with Monte Carlo simulation. The parameter that will be evaluated in sensitivity would be steam flow rate, turbine inlet pressure, and turbine exhaust pressure/atmospheric pressure. The result are probability for P10, P50, and P90 of gross power output which are 1.78 MWe, 2.22 MWe and 2.66 Mwe respectively. Whereas the P10, P50, and P90 of SSC are 4.67 kg/s/MWe, 5.19 kg/s/MWe and 5.78 kg/s/MWe respectively.

  9. Phase-Change Nanoparticles Using Highly Volatile Perfluorocarbons: Toward a Platform for Extravascular Ultrasound Imaging (United States)

    Matsunaga, Terry O.; Sheeran, Paul S.; Luois, Samantha; Streeter, Jason E.; Mullin, Lee B.; Banerjee, Bhaskar; Dayton, Paul A.


    Recent efforts using perfluorocarbon (PFC) nanoparticles in conjunction with acoustic droplet vaporization has introduced the possibility of expanding the diagnostic and therapeutic capability of ultrasound contrast agents to beyond the vascular space. Our laboratories have developed phase-change nanoparticles (PCNs) from the highly volatile PFCs decafluorobutane (DFB, bp =-2 °C) and octafluoropropane (OFP, bp =-37 °C ) for acoustic droplet vaporization. Studies with commonly used clinical ultrasound scanners have demonstrated the ability to vaporize PCN emulsions with frequencies and mechanical indices that may significantly decrease tissue bioeffects. In addition, these contrast agents can be formulated to be stable at physiological temperatures and the perfluorocarbons can be mixed to modulate the balance between sensitivity to ultrasound and general stability. We herein discuss our recent efforts to develop finely-tuned diagnostic/molecular imaging agents for tissue interrogation. We discuss studies currently under investigation as well as potential diagnostic and therapeutic paradigms that may emerge as a result of formulating PCNs with low boiling point PFCs. PMID:23382775

  10. Porous tungsten prepared by atmospheric-pressure chemical vapor deposition with WF6 and its characterization (United States)

    Li, Ying; Yu, Xiaodong; Tan, Chengwen; Wang, Fuchi; Ma, Honglei; Yue, Jintao


    Porous tungsten (W) is used in aeronautic and aerospace engineering, power electronics field and metallurgical industry. In this study, porous W with 98wt% W was prepared on a carbon foam substrate by atmospheric-pressure chemical vapor deposition (CVD) with tungsten fluoride (WF6) as the precursor. The porous W with 78.1346% porosity displayed a pure α-W phase and the uniform surface. The mode pore diameter of porous W is 208.0 µm. In a compression test, the fracture strength of porous W is 20.3 MPa.

  11. Evaluation of Vapor Pressure Estimation Methods for Use in Simulating the Dynamic of Atmospheric Organic Aerosols

    Directory of Open Access Journals (Sweden)

    A. J. Komkoua Mbienda


    Lee and Kesler (LK, and Ambrose-Walton (AW methods for estimating vapor pressures ( are tested against experimental data for a set of volatile organic compounds (VOC. required to determine gas-particle partitioning of such organic compounds is used as a parameter for simulating the dynamic of atmospheric aerosols. Here, we use the structure-property relationships of VOC to estimate . The accuracy of each of the aforementioned methods is also assessed for each class of compounds (hydrocarbons, monofunctionalized, difunctionalized, and tri- and more functionalized volatile organic species. It is found that the best method for each VOC depends on its functionality.

  12. Pressurization of a Flightweight, Liquid Hydrogen Tank: Evaporation & Condensation at a Liquid/Vapor Interface (United States)

    Stewart, Mark E. M.


    This paper presents an analysis and simulation of evaporation and condensation at a motionless liquid/vapor interface. A 1-D model equation, emphasizing heat and mass transfer at the interface, is solved in two ways, and incorporated into a subgrid interface model within a CFD simulation. Simulation predictions are compared with experimental data from the CPST Engineering Design Unit tank, a cryogenic fluid management test tank in 1-g. The numerical challenge here is the physics of the liquid/vapor interface; pressurizing the ullage heats it by several degrees, and sets up an interfacial temperature gradient that transfers heat to the liquid phase-the rate limiting step of condensation is heat conducted through the liquid and vapor. This physics occurs in thin thermal layers O(1 mm) on either side of the interface which is resolved by the subgrid interface model. An accommodation coefficient of 1.0 is used in the simulations which is consistent with theory and measurements. This model is predictive of evaporation/condensation rates, that is, there is no parameter tuning.

  13. 46 CFR 154.1836 - Vapor venting as a means of cargo tank pressure and temperature control. (United States)


    ... LIQUEFIED GASES Operations § 154.1836 Vapor venting as a means of cargo tank pressure and temperature... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... cargo pressure and temperature control system under §§ 154.701 through 154.709 is operating and that...

  14. The vapor pressures and activities of dicarboxylic acids reconsidered: the impact of the physical state of the aerosol

    Directory of Open Access Journals (Sweden)

    V. Soonsin


    Full Text Available We present vapor pressure data of the C2 to C5 dicarboxylic acids deduced from measured evaporation rates of single levitated particles as both, aqueous droplets and solid crystals. The data of aqueous solution particles over a wide concentration range allow us to directly calculate activities of the dicarboxylic acids and comparison of these activities with parameterizations reported in the literature. The data of the pure liquid state acids, i.e. the dicarboxylic acids in their supercooled melt state, exhibit no even-odd alternation in vapor pressure, while the acids in the solid form do. This observation is consistent with the known solubilities of the acids and our measured vapor pressures of the supercooled melt. Thus, the gas/particle partitioning of the different dicarboxylic acids in the atmosphere depends strongly on the physical state of the aerosol phase, the difference being largest for the even acids. Our results show also that, in general, measurements of vapor pressures of solid dicarboxylic acids may be compromised by the presence of polymorphic forms, crystalline structures with a high defect number, and/or solvent inclusions in the solid material, yielding a higher vapor pressure than the one of the thermodynamically stable crystalline form at the same temperature.

  15. H2O and CO2 vapor pressure measurements at temperatures relevant to the middle atmosphere of Earth and Mars (United States)

    Nachbar, M.; Duft, D.; Leisner, T.


    Measurements of the vapor pressure of H2O and CO2 at temperatures relevant to the middle atmosphere of Earth and Mars are rare but important in order to describe cloud formation and ice particle growth processes. In this contribution we present a novel technique for measuring the vapor pressure of condensable gases by analyzing the depositional growth rates on free nanoparticles at high supersaturation. The method is applied to measure the vapor pressure of CO2 between 75K and 85K. By comparison with previous measurements and parameterizations we are able to show the excellent functionality of the method. In addition, the method is used to measure the vapor pressure over H2O ice between 135K and 160K. We show that the vapor pressure of so called stacking disordered ice Isd deposited at temperatures below 160K is significantly higher compared to hexagonal ice Ih. The consequences for ice cloud formation in the atmosphere of Earth and Mars will be discussed.

  16. Atmospheric pressure synthesis of photoluminescent hybrid materials by sequential organometallic vapor infiltration into polyethylene terephthalate fibers (United States)

    Akyildiz, Halil I.; Mousa, Moataz Bellah M.; Jur, Jesse S.


    Exposing a polymer to sequential organometallic vapor infiltration (SVI) under low pressure conditions can significantly modify the polymer's chemical, mechanical, and optical properties. We demonstrate that SVI of trimethylaluminum into polyethylene terephthalate (PET) can also proceed readily at atmospheric pressure, and at 60 °C the extent of reaction determined by mass uptake is independent of pressure between 2.5 Torr and 760 Torr. At 120 °C, however, the mass gain is 50% larger at 2.5 Torr relative to that at 760 Torr, indicating that the precursor diffusion in the chamber and fiber matrix decreases at higher source pressure. Mass gain decreases, in general, as the SVI process temperature increases both at 2.5 Torr and 760 Torr attributed to the faster reaction kinetics forming a barrier layer, which prevents further diffusion of the reactive species. The resulting PET/Al-Ox product shows high photoluminescence compared to untreated fibers. A physical mask on the polymer during infiltration at 760 Torr is replicated in the underlying polymer, producing an image in the polymer that is visible under UV illumination. Because of the reduced precursor diffusivity during exposure at 760 Torr, the image shows improved resolution compared to SVI performed under typical 2.5 Torr conditions.

  17. High-pressure vapor-liquid equilibria of two binary systems: Carbon dioxide + cyclohexanol and carbon dioxide + cyclohexanone

    Energy Technology Data Exchange (ETDEWEB)

    Laugier, S. [Ecole Nationale Superieure de Chimie et Physique de Bordeaux, Talence (France); Richon, D. [Ecole Nationale Superieure des Mines de Paris, Fontainebleau (France)


    Vapor-liquid equilibria for carbon dioxide + cyclohexanol and carbon dioxide + cyclohexanone were measured using an apparatus based on a static-analytic method with in situ samplings. P, T, x, y measurements were made at pressures up to 22 MPa. The carbon dioxide + cyclohexanol system was studied at 433 and 473 K, and carbon dioxide + cyclohexanone, at 433 and 473 K. The results are correlated by the Redlich-Kwong-Soave and Peng and Robinson equations and several mixing rules. The best fittings are obtained with the Peng-Robinson equation of state and a two-parameter mixing rule, i.e., within 1.1% for both pressures and vapor mole fractions on the carbon dioxide + cyclohexanone system and within 1.9% for pressures and 2.9% for vapor mole fractions on the carbon dioxide + cyclohexanol system. More recent equations by Patel and Teja and Salim and Trebble show no significant advantages.

  18. Effect of Vapor Pressure Scheme on Multiday Evolution of SOA in an Explicit Model (United States)

    Lee-Taylor, J.; Madronich, S.; Aumont, B.; Camredon, M.; Emmons, L. K.; Tyndall, G. S.; Valorso, R.


    Recent modeling of the evolution of Secondary Organic Aerosol (SOA) has led to the critically important prediction that SOA mass continues to increase for several days after emission of primary pollutants. This growth of organic aerosol in dispersing plumes originating from urban point sources has direct implications for regional aerosol radiative forcing. We investigate the robustness of predicted SOA mass growth downwind of Mexico City in the model GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere), by assessing its sensitivity to the choice of vapor pressure prediction scheme. We also explore the implications for multi-day SOA mass growth of glassification / solidification of SOA constituents during aging. Finally we use output from the MOZART-4 chemical transport model to evaluate our results in the regional and global context.

  19. Luminescence of mesoporous silicon powders treated by high-pressure water vapor annealing (United States)

    Gelloz, Bernard; Loni, Armando; Canham, Leigh; Koshida, Nobuyoshi


    We have studied the photoluminescence of nanocrystalline silicon microparticle powders fabricated by fragmentation of PSi membranes. Several porosities were studied. Some powders have been subjected to further chemical etching in HF in order to reduce the size of the silicon skeleton and reach quantum sizes. High-pressure water vapor annealing was then used to enhance both the luminescence efficiency and stability. Two visible emission bands were observed. A red band characteristic of the emission of Si nanocrystals and a blue band related to localized centers in oxidized powders. The blue band included a long-lived component, with a lifetime exceeding 1 sec. Both emission bands depended strongly on the PSi initial porosity. The colors of the processed powders were tunable from brown to off-white, depending on the level of oxidation. The surface area and pore volume of some powders were also measured and discussed. The targeted applications are in cosmetics and medicine.

  20. The predictable influence of soil temperature and barometric pressure changes on vapor intrusion (United States)

    Barnes, David L.; McRae, Mary F.


    Intrusion of volatile organic compounds in the gas phase has impacted many buildings in many different locations. Various building and environmental factors such as buoyancy of heated air and changes in barometric pressure can influence indoor air concentrations due to vapor intrusion in these buildings resulting in seasonal and daily variability. One environmental factor that previous research has not adequately addressed is soil temperature. In this study we present two northern region study sites where the seasonal trends in indoor air VOC concentrations positively correlate with soil temperature, and short-term (days) variations are associated with barometric pressure changes. We present simple and multivariate linear relationships of indoor air concentrations as a function of soil temperature and barometric pressure. Results from this study show that small changes in soil temperature can result in relatively large changes in indoor air VOC concentrations where the gas phase VOCs are sourced from non-aqueous phase liquids contained in the soil. We use the results from this study to show that a five degree Celsius increase in soil temperature, a variation in soil temperature that is possible in many climatic regions, results in a two-fold increase in indoor air VOC concentrations. Additionally, analysis provides insight into how building ventilation, diffusion, and the relative rate of soil-gas flow across the slab both from the subsurface into the building and from the building into the subsurface impact short term variations in concentrations. With these results we are able to provide monitoring recommendations for practitioners.

  1. Measurement and modeling of high-pressure (vapor + liquid) equilibria of (CO{sub 2} + alkanol) binary systems

    Energy Technology Data Exchange (ETDEWEB)

    Bejarano, Arturo; Gutierrez, Jorge E. [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Araus, Karina A. [Departamento de Ingenieria Quimica y Bioprocesos, Pontificia Universidad Catolica de Chile, Avda. Vicuna Mackenna 4860, Macul, Santiago (Chile); Fuente, Juan C. de la, E-mail: juan.delafuente@usm.c [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Centro Regional de Estudios en Alimentos Saludables, Blanco 1623, Valparaiso (Chile)


    Research highlights: (Vapor + liquid) equilibria of three (CO{sub 2} + C{sub 5} alcohol) binary systems were measured. Complementary data are reported at (313, 323 and 333) K and from (2 to 11) MPa. No liquid immiscibility was observed at the temperatures and pressures studied. Experimental data were correlated with the PR-EoS and the van de Waals mixing rules. Correlation results showed relative deviations {<=}8 % (liquid) and {<=}2 % (vapor). - Abstract: Complementary isothermal (vapor + liquid) equilibria data are reported for the (CO{sub 2} + 3-methyl-2-butanol), (CO{sub 2} + 2-pentanol), and (CO{sub 2} + 3-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 11) MPa. For all (CO{sub 2} + alcohol) systems, it was visually monitored that there was no liquid immiscibility at the temperatures and pressures studied. The experimental data were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapor + liquid) equilibria compositions were found to be in good agreement with the experimental data with deviations for the mole fractions <8% and <2% for the liquid and vapor phase, respectively.

  2. Optimizing Acoustic Activation of Phase Change Contrast Agents with the Activation Pressure Matching Method: A Review. (United States)

    Rojas, Juan D; Dayton, Paul A


    Sub-micron phase-change contrast agents consist of a liquid perfluorocarbon core that can be vaporized by ultrasound (acoustic droplet vaporization) to generate contrast with excellent spatial and temporal control. When these agents, commonly referred to as nanodroplets, are formulated with cores of low boiling-point perfluorocarbons such as decafluorobutane and octafluoropropane, they can be activated with lowmechanical index imaging pulses for diagnostic applications. Since the utilization of minimum mechanical index is often desirable to avoid unnecessary biological effects, enabling consistent activation of these agents in an acoustic field is a challenge because the energy that must be delivered to achieve the vaporization threshold increases with depth due to attenuation. A novel vaporization approach called Activation Pressure Matching has been developed to deliver the same pressure throughout a field of view in order to produce uniform nanodroplet vaporization and to limit the amount of energy that is delivered. In this manuscript, we discuss the application of this method with a Versasonics V1 Research Ultrasound System to modulate the output pressure from an ATL L11-5 transducer. Vaporization-pulse spacing optimization can be used in addition to matching the activation pressure through depth, and we demonstrate the feasibility of this approach both in vivo and in vitro. The use of optimized vaporization parameters increases the amount of time a single bolus of nanodroplets can generate useful contrast and provides consistent image enhancement in vivo. Therefore, APM is a useful technique for those wishing to maximize the efficacy of phase change contrast agent while minimizing delivered acoustic energy.

  3. 21 CFR 177.2400 - Perfluorocarbon cured elastomers. (United States)


    ... components of articles intended for repeated use in contact with nonacid food (pH above 5.0), subject to the..._locations.html. (2) Thermogravimetry. Perfluorocarbon cured elastomers have a major decomposition peak...

  4. The Comparative Study on Vapor-Polymerization and Pressure-dependent Conductance Behavior in Polypyrrole-hybridized Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Hanif, Zahid; Lee, Seyeong; Arsalani, Nasir; Geckeler, Kurt E.; Hong, Sukwon; Yoon, Myung-Han [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of)


    In this study, commercially available cellulose membranes were hybridized with conjugated polymer via vapor-phase polymerization using pyrrole and iron chloride as a monomer and oxidant, respectively. The iron (III) chloride layer dip-coated on the hydrophilic cell ulose surface oxidized the vaporized pyrrole monomer leading to the polypyrrole-cellulose hybrid membrane. The conductivity of hybrid membrane was optimized by varying the oxidant concentration and the monomer vapor exposure time. The various surface characterizations of polypyrrole-cellulose hybrid membrane show that the conductive polypyrrole layer was uniformly deposited onto the surface of cellulose fibrous networks unlike the polypyrrole-nylonhybrid membrane prepared in the similar way. The polypyrrole-incorporated cellulose networks exhibits steeper electrical conductance increase over the vertical pressure than its nylon counterpart. Our result suggests that the polypyrrole-cellulose hybrid membrane can be applicable for a disposable high-load pressure sensor.

  5. [Measurement of atomic number of alkali vapor and pressure of buffer gas based on atomic absorption]. (United States)

    Zheng, Hui-jie; Quan, Wei; Liu, Xiang; Chen, Yao; Lu, Ji-xi


    High sensitivitymagnetic measurementscanbe achieved by utilizing atomic spinmanipulation in the spin-exchange-relaxation-free (SERF) regime, which uses an alkali cell as a sensing element. The atomic number density of the alkali vapor and the pressure of the buffer gasare among the most important parameters of the cell andrequire accurate measurement. A method has been proposed and developedto measure the atomic number density and the pressure based on absorption spectroscopy, by sweeping the absorption line and fittingthe experiment data with a Lorentzian profile to obtainboth parameters. Due to Doppler broadening and pressure broadening, which is mainly dominated by the temperature of the cell and the pressure of buffer gas respectively, this work demonstrates a simulation of the errorbetween the peaks of the Lorentzian profile and the Voigt profile caused by bothfactors. The results indicates that the Doppler broadening contribution is insignificant with an error less than 0.015% at 313-513 K for a 4He density of 2 amg, and an error of 0.1% in the presence of 0.6-5 amg at 393 K. We conclude that the Doppler broadening could be ignored under above conditions, and that the Lorentzianprofile is suitably applied to fit the absorption spectrumobtainingboth parameters simultaneously. In addition we discuss the resolution and the instability due to thelight source, wavelength and the temperature of the cell. We find that the cell temperature, whose uncertainty is two orders of magnitude larger than the instability of the light source and the wavelength, is one of the main factors which contributes to the error.

  6. Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics

    CERN Document Server

    Makarieva, A M; Sheil, D; Nobre, A D; Li, B -L


    Phase transitions of atmospheric water play a ubiquitous role in the Earth's climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric pressure through the mass removal of water from the gas phase with a simultaneous account of the latent heat release. Building from the fundamental physical principles we show that condensation is associated with a decline in air pressure in the lower atmosphere. This decline occurs up to a certain height, which ranges from 3 to 4 km for surface temperatures from 10 to 30 deg C. We then estimate the horizontal pressure differences associated with water vapor condensation and find that these are comparable in magnitude with the pressure differences driving observed circulation patterns. The water vapor delivered to the atmosphere via evaporation represents a store of potential energy available to accelerate air and thus drive winds. Our estimates suggest that the...

  7. Determination of saturation pressure and enthalpy of vaporization of semi-volatile aerosols: the integrated volume mentod (United States)

    This study presents the integrated volume method for estimating saturation pressure and enthalpy of vaporization of a whole aerosol distribution. We measure the change of total volume of an aerosol distribution between a reference state and several heated states, with the heating...

  8. Electrical properties of low pressure chemical vapor deposited silicon nitride thin films for temperatures up to 650 °C

    NARCIS (Netherlands)

    Tiggelaar, Roald M.; Groenland, A.W.; Sanders, Remco G.P.; Gardeniers, Johannes G.E.


    The results of a study on electrical conduction in low pressure chemical vapor deposited silicon nitride thin films for temperatures up to 650 °C are described. Current density versus electrical field characteristics are measured as a function of temperature for 100 and 200 nm thick stoichiometric

  9. Controlled Growth of Non-Uniform Arsenic Profiles in Silicon Reduced-Pressure Chemical Vapor Deposition Epitaxial Layers

    NARCIS (Netherlands)

    Popadic, M.; Scholtes, T.L.M.; De Boer, W.; Sarubbi, F.; Nanver, L.K.


    An empirical model of As surface segregation during reduced-pressure chemical vapor deposition Si epitaxy is presented. This segregation mechanism determines the resulting doping profile in the grown layer and is here described by a model of simultaneous and independent As adsorption and segregation

  10. Membership function model for defining optimality of vapor pressure deficit in closed-field cultivation of tomato

    NARCIS (Netherlands)

    Shamshiri, R.; Che Man, H.; Zakaria, A.J.; Beveren, van Peter; Wan Ismail, W.I.; Ahmad, D.


    Estimation of plant's evapotranspiration (ET) or water loss to the atmosphere depends on the vapor pressure deficit (VPD) of the closed-field environment (greenhouse). The objective of this work was to develop a membership function model for defining optimal VPD of greenhouse air for tomato

  11. A thermodynamic study of glucose and related oligomers in aqueous solution: Vapor pressures and enthalpies of mixing

    DEFF Research Database (Denmark)

    Cooke, S.A.; Jonsdottir, Svava Osk; Westh, Peter


    -mentioned systems at 318.15 K. A theoretical model is examined in which existing interaction parameters, calculated for the water + 1,2-ethanediol system by using a molecular mechanical approach, are incorporated into the UNIQUAC equation to describe the vapor pressures of the aforementioned series of saccharides...

  12. An Integrated Approach to Introducing Biofuels, Flash Point, and Vapor Pressure Concepts into an Introductory College Chemistry Lab (United States)

    Hoffman, Adam R.; Britton, Stephanie L.; Cadwell, Katie D.; Walz, Kenneth A.


    Students explore the fundamental chemical concepts of vapor pressure and flash point in a real-world technical context, while gaining insight into the contemporary societal issue of biofuels. Lab activities were developed using a closed-cup instrument to measure the flash point of various biodiesel samples. Pre- and post-tests revealed that the…

  13. Ultrasound-Mediated Tumor Imaging and Nanotherapy using Drug Loaded, Block Copolymer Stabilized Perfluorocarbon Nanoemulsions (United States)

    Rapoport, Natalya; Nam, Kweon-Ho; Gupta, Roohi; Gao, Zhongao; Mohan, Praveena; Payne, Allison; Todd, Nick; Liu, Xin; Kim, Taeho; Shea, Jill; Scaife, Courtney; Parker, Dennis L.; Jeong, Eun-Kee; Kennedy, Anne M.


    Perfluorocarbon nanoemulsions can deliver lipophilic therapeutic agents to solid tumors and simultaneously provide for monitoring nanocarrier biodistribution via ultrasonography and/or 19F MRI. In the first generation of block copolymer stabilized perfluorocarbon nanoemulsions, perfluoropentane (PFP) was used as the droplet forming compound. Although manifesting excellent therapeutic and ultrasound imaging properties, PFP nanoemulsions were unstable at storage, difficult to handle, and underwent hard to control phenomenon of irreversible droplet-to-bubble transition upon injection. To solve the above problems, perfluoro-15-crown-5-ether (PFCE) was used as a core forming compound in the second generation of block copolymer stabilized perfluorocarbon nanoemulsions. PFCE nanodroplets manifest both ultrasound and fluorine (19F) MR contrast properties, which allows using multimodal imaging and 19F MR spectroscopy for monitoring nanodroplet pharmacokinetics and biodistribution. In the present paper, acoustic, imaging, and therapeutic properties of unloaded and paclitaxel (PTX) loaded PFCE nanoemulsions are reported. As manifested by the 19F MR spectroscopy, PFCE nanodroplets are long circulating, with about 50% of the injected dose remaining in circulation two hours after the systemic injection. Sonication with 1-MHz therapeutic ultrasound triggered reversible droplet-to-bubble transition in PFCE nanoemulsions. Microbubbles formed by acoustic vaporization of nanodroplets underwent stable cavitation. The nanodroplet size (200 nm to 350 nm depending on a type of the shell and conditions of emulsification) as well as long residence in circulation favored their passive accumulation in tumor tissue that was confirmed by ultrasonography. In the breast and pancreatic cancer animal models, ultrasound-mediated therapy with paclitaxel-loaded PFCE nanoemulsions showed excellent therapeutic properties characterized by tumor regression and suppression of metastasis. Anticipated

  14. Perfluorocarbon Nanoparticles:. A Theranostic Platform Technology (United States)

    Lanza, Gregory M.; Winter, Patrick M.; Caruthers, Shelton D.; Hughes, Michael S.; Hu, Grace; Pan, Dipanjan; Schmieder, Anne H.; Pham, Christine; Wickline, Samuel A.


    Nanomedicine clearly offers unique tools to address intractable medical problems in cancer and cardiovascular disease from entirely new perspectives. Among the theranostic options emerging in this new wave of biotechnology development, the perfluorocarbon nanoparticles have shown robust potential in vivo for diagnosing, characterizing, treating and following proliferating cancers, progressive atherosclerosis, rheumatoid arthritis and much more. These molecular imaging agents have been demonstrated for use with ultrasound, MRI, CT, and SPECT/CT. Moreover, the synergism of imaging for confirmation of therapeutic delivery, for dosimetry, and for noninvasively following early treatment responses is discussed. Image-guided drug delivery based on nanotechnology is emerging as a powerful clinical opportunity, and PFC nanoparticles are among the leading technologies reaching clinical testing today with this potential.

  15. Delayed inflammation associated with retained perfluorocarbon liquid

    Directory of Open Access Journals (Sweden)

    S Pradeep


    Full Text Available A 55-year-old woman, with history of cataract surgery 1 year back, presented with features of ocular inflammation for last 3 months. She had no history of any other intraocular surgery. On examination, anterior segment showed frothy material in the inferior angle with moderate anterior chamber reaction (cells+/flare+ and sulcus intraocular lens with large posterior capsule rent. Fundoscopy showed multiple, small to medium-sized transparent bubbles of perfluorocarbon liquid (PFCL with membranes in the vitreous cavity. Ultrasonography confirmed the presence of PFCL in the vitreous cavity. Pars plana vitrectomy with anterior chamber wash was done which led to good visual recovery. To conclude, retained PFCL can cause late onset fibrinous inflammation after a quiescent period but surgical intervention may lead to good visual outcome.


    Directory of Open Access Journals (Sweden)

    Nélio T. MACHADO


    Full Text Available Vapor-Liquid equilibria of palm fatty acids distillates/carbon dioxide system has been investigated experimentally at temperatures of 333, 353, and 373 K and pressures of 20, 23, 26, and 29 MPa using the static method. Experimental data for the quasi-binary system palm fatty acids distillates/carbon dioxide has been correlated with Redlich-Kwong-Aspen equation of state. Modeling shows good agreement with experimental data. Selectivity obtained indicates that supercritical carbon dioxide is a reasonable solvent for separating saturated (palmitic acid and unsaturated (oleic+linoleic acids fatty acids from palm fatty acids distillates in a continuous multistage countercurrent column.Foi investigado experimentalmente o equilíbrio líquido-vapor para o sistema Destilado Ácido de Óleo de Palma (PFAD/Dióxido de Carbono, nas temperaturas de 333, 353 e 373 K e pressões de 20, 23, 26 e 29 MPa, usando-se o método estático. Os dados experimentais do sistema pseudo-binário PFAD/CO2 foram correlacionados com a equação de estado de Redlich-Kwong do pacote computacional ASPEN. O modelo reproduz bem os resultados experimentais. A seletividade obtida indica que o CO2 supercrítico é um solvente razoável para a separação em coluna multi-estágio e contínua, do ácido graxo saturado (ácido palmítico daqueles insaturados (ácido oleico e ácido linoleico contidos no PFAD.

  17. Electron transport in mercury vapor: cross sections, pressure and temperature dependence of transport coefficients and NDC effects★ (United States)

    Mirić, Jasmina; Simonović, Ilija; Petrović, Zoran Lj.; White, Ronald D.; Dujko, Saša


    In this work we propose a complete and consistent set of cross sections for electron scattering in mercury vapor. The set is validated through a series of comparisons between swarm data calculated using a multi term theory for solving the Boltzmann equation and Monte Carlo simulations, and the available experimental data. Other sets of cross sections for electron scattering in mercury vapor were also used as input in our numerical codes with the aim of testing their completeness, consistency and accuracy. The calculated swarm parameters are compared with measurements in order to assess the quality of the cross sections in providing data for plasma modeling. In particular, we discuss the dependence of transport coefficients on the pressure and temperature of mercury vapor, and the occurrence of negative differential conductivity (NDC) in the limit of lower values of E/N. We have shown that the phenomenon of NDC is induced by the presence of mercury dimers and that can be controlled by varying either pressure or temperature of mercury vapor. The effective inelastic cross section for mercury dimers is estimated for a range of pressures and temperatures. It is shown that the measured and calculated drift velocities agree very well only if the effective inelastic cross section for mercury dimers and thermal motion of mercury atoms are carefully considered and implemented in numerical calculations. Contribution to the Topical Issue "Physics of Ionized Gases (SPIG 2016)", edited by Goran Poparic, Bratislav Obradovic, Dragana Maric and Aleksandar Milosavljevic.

  18. Effect of Furnish on Temperature and Vapor Pressure Behavior in the Center of Mat Panels during Hot Pressing

    Directory of Open Access Journals (Sweden)

    Muhammad Navis Rofii


    Full Text Available Particleboard achieves its overall performance characteristics during hot pressing process. As this process is influenced by several factors, particularly temperature and pressure, it is very important to understand the behavior of both. This study investigates the effects of furnish materials on temperature and vapor pressure behavior inside particleboard mat panels during hot pressing. Strand type particles from hinoki and ring-flaker recycled wood particles were used as furnish for laboratory-scale particleboard panels with a target density of 0.76 g/cm³. Mat panels with a moisture content of about 10% were hot pressed at a platen temperature of 180°C and an initial pressure of 3 MPa until the mat center reached the same temperature as the platen. A press monitoring device (PressMAN Lite was used for detecting the temperature and vapor pressure change in the center of the mat panels. The study showed that the furnish type affected the temperature and vapor behavior inside the mat panels. Particleboard made of hinoki strand resulted in a longer plateau time, a higher plateau temperature and a higher gas pressure generated during hot pressing than those of ring-flaker recycled wood particles. Mixed board resulted in values between those of the two other furnish materials.


    Directory of Open Access Journals (Sweden)

    R. V. Ralys


    Full Text Available Subject of Study.Research of vapor pressure of low volatile substances is a complicated problem due to both direct experimental implementation complexity and, most significantly, the issues faced correctness of the analysis and processing of experimental data. That is why it is usually required engaging the reference substances (with vapor pressures well studied. The latter drastically reduces the effectiveness of the experimental methods used and narrows their applicability. The paper deals with an approach to the evaporation process description (sublimation of low volatile substances based on molecular kinetic description in view of diffusive and convection processes. The proposed approach relies on experimental thermogravimetricfindingsina wide range of temperatures, flow rates ofthe purge gas and time. Method. A new approach is based on the calculation of the vapor pressure and uses the data about the speed of evaporation by thermogravimetric analysis depending on the temperature, the flow rate of the purge gas, and the evaporation time. The basis for calculation is the diffusion-kinetic description of the process of evaporation (mass loss of the substance from the exposed surface. The method is applicable to determine the thermodynamic characteristics for both the evaporation (the equilibrium liquid - vapor and sublimation (the equilibrium solid - vapor. We proposed the appropriate method of the experiment and analysis of its data in order to find the saturated vapor pressure of individual substances of low volatility. Main Results. The method has been tested on substances with insufficiently reliable and complete study of the thermodynamic characteristics but, despite this, are often used (because of the other data limitations as reference ones. The vaporization process (liquid-vapor has been studied for di-n-butyl phthalate C16H22O4 at 323,15–443,15 К, and sublimation for benzoic acid C7H6O2at 303,15–183,15 К. Both processes have

  20. Complementary vapor pressure data for 2-methyl-1-propanol and 3-methyl-1-butanol at a pressure range of (15 to 177) kPa

    Energy Technology Data Exchange (ETDEWEB)

    Bejarano, Arturo; Quezada, Nathalie [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Fuente, Juan C. de la [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile)], E-mail:


    The vapor pressure of pure 2-methyl-1-propanol and 3-methyl-1-butanol, components called congeners that are present in aroma of wine, pisco, and other alcoholic beverages, were measured with a dynamic recirculation apparatus at a pressure range of (15 to 177) kPa with an estimated uncertainty <0.2%. The measurements were performed at temperature ranges of (337 to 392) K for 2-methyl-1-propanol and (358 to 422) K for 3-methyl-1-butanol. Data were correlated using a Wagner-type equation with standard deviations of 0.09 kPa for the vapor pressure of 2-methyl-1-propanol and 0.21 kPa for 3-methyl-1-butanol. The experimental data and correlation were compared with data selected from the literature.

  1. Flexible Electronics: High Pressure Chemical Vapor Deposition of Hydrogenated Amorphous Silicon Films and Solar Cells (Adv. Mater. 28/2016). (United States)

    He, Rongrui; Day, Todd D; Sparks, Justin R; Sullivan, Nichole F; Badding, John V


    On page 5939, J. V. Badding and co-workers describe the unrolling of a flexible hydrogenated amorphous silicon solar cell, deposited by high-pressure chemical vapor deposition. The high-pressure deposition process is represented by the molecules of silane infiltrating the small voids between the rolled up substrate, facilitating plasma-free deposition over a very large area. The high-pressure approach is expected to also find application for 3D nanoarchitectures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Use of Interrupted Helium Flow in the Analysis of Vapor Samples with Flowing Atmospheric-Pressure Afterglow-Mass Spectrometry (United States)

    Storey, Andrew P.; Zeiri, Offer M.; Ray, Steven J.; Hieftje, Gary M.


    The flowing atmospheric-pressure afterglow (FAPA) source was used for the mass-spectrometric analysis of vapor samples introduced between the source and mass spectrometer inlet. Through interrupted operation of the plasma-supporting helium flow, helium consumption is greatly reduced and dynamic gas behavior occurs that was characterized by schlieren imaging. Moreover, mass spectra acquired immediately after the onset of helium flow exhibit a signal spike before declining and ultimately reaching a steady level. This initial signal appears to be due to greater interaction of sample vapor with the afterglow of the source when helium flow resumes. In part, the initial spike in signal can be attributed to a pooling of analyte vapor in the absence of helium flow from the source. Time-resolved schlieren imaging of the helium flow during on and off cycles provided insight into gas-flow patterns between the FAPA source and the MS inlet that were correlated with mass-spectral data.

  3. The Relative Importance of Aqueous vs. Vapor-Pressure Dependent Pathways for Particulate Organic Nitrate Formation (United States)

    Zare, A.; Pye, H. O. T.; Cohen, R. C.


    Formation of biogenic derived organic nitrates is known as an important immediate sink of atmospheric nitrogen oxides. Although, subsequent oxidation and photolysis of organic nitrates can return a part of the sequestered NOx to the atmosphere, other removal pathways in combination with wet and dry deposition and hydrolysis of particulate organic nitrates is of central importance in irreversible NOx removal from the atmosphere. The aim of this work is to understand how and to what degree the particle phase participates in removal of NOx. We implement a new BVOC oxidation gas phase mechanism (including a detailed representation of OH- and NO3-initiated organic nitrates) and an explicit representation of organic nitrate aerosols formation, including irreversible aqueous-phase uptake and reversible partitioning onto pre-existing organic aerosol, into the CMAQ model. Using these mechanisms, we simulate observations from the SOAS field campaigns over the southeast US in summer 2013 and examine the relative role of water-mediated vs vapor pressure processes in determining aerosol from organic nitrates.

  4. Uniformly Distributed Graphene Domain Grows on Standing Copper via Low-Pressure Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Shih-Hao Chan


    Full Text Available Uniformly distributed graphene domains were synthesized on standing copper foil by a low-pressure chemical vapor deposition system. This method improved the distribution of the graphene domains at different positions on the same piece of copper foil along the forward direction of the gas flow. Scanning electron microscopy (SEM showed the average size of the graphene domains to be about ~20 m. This results show that the sheet resistance of monolayer graphene on a polyethylene terephthalate (PET substrate is about ~359 /□ whereas that of the four-layer graphene films is about ~178 /□, with a transmittance value of 88.86% at the 550 nm wavelength. Furthermore, the sheet resistance can be reduced with the addition of HNO3 resulting in a value of 84 /□. These values meet the absolute standard for touch sensor applications, so we believe that this method can be a candidate for some transparent conductive electrode applications.

  5. Vapor-pressure deficit and extreme climatic variables limit tree growth. (United States)

    Sanginés de Cárcer, Paula; Vitasse, Yann; Peñuelas, Josep; Jassey, Vincent E J; Buttler, Alexandre; Signarbieux, Constant


    Assessing the effect of global warming on forest growth requires a better understanding of species-specific responses to climate change conditions. Norway spruce and European beech are among the dominant tree species in Europe and are largely used by the timber industry. Their sensitivity to changes in climate and extreme climatic events, however, endangers their future sustainability. Identifying the key climatic factors limiting their growth and survival is therefore crucial for assessing the responses of these two species to ongoing climate change. We studied the vulnerability of beech and spruce to warmer and drier conditions by transplanting saplings from the top to the bottom of an elevational gradient in the Jura Mountains in Switzerland. We (1) demonstrated that a longer growing season due to warming could not fully account for the positive growth responses, and the positive effect on sapling productivity was species-dependent, (2) demonstrated that the contrasting growth responses of beech and spruce were mainly due to different sensitivities to elevated vapor-pressure deficits (VPD), (3) determined the species-specific limits to VPD above which growth rate began to decline, and (4) demonstrated that models incorporating extreme climatic events could account for the response of growth to warming better than models using only average values. These results support that the sustainability of forest trees in the coming decades will depend on how extreme climatic events will change, irrespective of the overall warming trend. © 2017 John Wiley & Sons Ltd.

  6. Vapor pressures, aqueous solubilities, and Henry's law constants of some brominated flame retardants. (United States)

    Tittlemier, Sheryl A; Halldorson, Thor; Stern, Gary A; Tomy, Gregg T


    The subcooled liquid vapor pressures (P0(L),25S) and aqueous solubilities (Sw,25s) were determined and Henry's law constants (H25s) were estimated for a number of brominated flame retardants (BFRs) at 25 degrees C. The established methods of the gas chromatography-retention time and generator column techniques were used to experimentally determine P0(L),25 and Sw,25 for hexabromobenzene and a series of brominated diphenyl ether (BDE) congeners. The H25 was estimated as the ratio of P0(L)25 to the subcooled liquid aqueous solubility. Values of PL0(L),25 obtained ranged from 0.000000282 Pa (BDE-190) to 0.259 Pa (BDE-3); Sw,25 ranged from 0.00000087 g/L (BDE-153 and BDE-154) to 0.00013 g/L (BDE-15); and H25 ranged from 0.0074 Pa m3/mol (BDE-183) to 21 Pa m3/mol (BDE-15). An increase in the bromine content of polybrominated diphenyl ether congeners resulted in significant decreases Of P0(L),25, Sw25, and H25. A simple four-compartment equilibrium distribution model suggested that the majority of BFRs being released into the environment would reside in soil and sediment and have localized distributions. The model also suggested that lower brominated congeners tend to be somewhat more mobile. Degradative debromination reactions that yield these congeners would mobilize them environmentally, and ultimately affect the fate and distribution of BFRs.

  7. Prediction of aqueous solubility, vapor pressure and critical micelle concentration for aquatic partitioning of perfluorinated chemicals. (United States)

    Bhhatarai, Barun; Gramatica, Paola


    The majority of perfluorinated chemicals (PFCs) are of increasing risk to biota and environment due to their physicochemical stability, wide transport in the environment and difficulty in biodegradation. It is necessary to identify and prioritize these harmful PFCs and to characterize their physicochemical properties that govern the solubility, distribution and fate of these chemicals in an aquatic ecosystem. Therefore, available experimental data (10-35 compounds) of three important properties: aqueous solubility (AqS), vapor pressure (VP) and critical micelle concentration (CMC) on per- and polyfluorinated compounds were collected for quantitative structure-property relationship (QSPR) modeling. Simple and robust models based on theoretical molecular descriptors were developed and externally validated for predictivity. Model predictions on selected PFCs were compared with available experimental data and other published in silico predictions. The structural applicability domains (AD) of the models were verified on a bigger data set of 221 compounds. The predicted properties of the chemicals that are within the AD, are reliable, and they help to reduce the wide data gap that exists. Moreover, the predictions of AqS, VP, and CMC of most common PFCs were evaluated to understand the aquatic partitioning and to derive a relation with the available experimental data of bioconcentration factor (BCF).

  8. Nematicidal potential of hydrolates from the semi industrial vapor-pressure extraction of Spanish aromatic plants. (United States)

    Andrés, Maria Fe; González-Coloma, Azucena; Muñoz, Ruben; De la Peña, Felipe; Julio, Luis Fernando; Burillo, Jesus


    The nematicidal activity of hydrolate by-products from the semi industrial vapor-pressure essential oil extraction of selected aromatic plant species (commercial: Lavandula × intermedia Emeric ex Loisel. var. super, Thymus vulgaris L., T. zygis Loefl ex L. and experimentally pre-domesticated: L. luisieri (Rozeira) Rivas-Martínez) was investigated against the root-knot nematode Meloidogyne javanica by in vitro and in vivo bioassays. Liquid-liquid extraction of hydrolates yielded the corresponding aqueous and organic fractions which were biological and chemically studied. Hydrolates from L. × intermedia var. super, L. luisieri, T. vulgaris, and T. zygis showed strong in vitro nematicidal effects against M. javanica (J2 mortality and suppression of egg hatching). In the case of the Thymus species, the active components were found in the organic fraction, characterized by thymol as major component. Conversely, the nematicidal activity of L. × intermedia var. super and L. luisieri remained in the corresponding aqueous fractions. In vivo tests on tomato seedlings at sublethal doses of the hydrolates/organic fractions induced a significant reduction of nematode infectivity. In pot experiments, all hydrolates tested on tomato plants significantly affect the infection frequency and reproduction rate of the nematode population. This study demonstrates that L. × intermedia var. super, L. luisieri, T. vulgaris, and T. zygis hydrolates could be an exploitable source of potential waste protection products on root-knot nematodes.

  9. Low-Pressure Vapor-Assisted Solution Process for Thiocyanate-Based Pseudohalide Perovskite Solar Cells. (United States)

    Chiang, Yu-Hsien; Cheng, Hsin-Min; Li, Ming-Hsien; Guo, Tzung-Fang; Chen, Peter


    In this report, we fabricated thiocyanate-based perovskite solar cells with low-pressure vapor-assisted solution process (LP-VASP) method. Photovoltaic performances are evaluated with detailed materials characterizations. Scanning electron microscopy images show that SCN-based perovskite films fabricated using LP-VASP have long-range uniform morphology and large grain sizes up to 1 μm. The XRD and Raman spectra were employed to observe the characteristic peaks for both SCN-based and pure CH3 NH3 PbI3 perovskite. We observed that the Pb(SCN)2 film transformed to PbI2 before the formation of perovskite film. X-ray photoemission spectra (XPS) show that only a small amount of S remained in the film. Using LP-VASP method, we fabricated SCN-based perovskite solar cells and achieved a power conversion efficiency of 12.72 %. It is worth noting that the price of Pb(SCN)2 is only 4 % of PbI2 . These results demonstrate that pseudo-halide perovskites are promising materials for fabricating low-cost perovskite solar cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Vapor Pressure and Predicted Stability of American Contact Dermatitis Society Core Allergens. (United States)

    Jou, Paul C; Siegel, Paul D; Warshaw, Erin M


    Accurate patch testing is reliant on proper preparation of patch test allergens. The stability of patch test allergens is dependent on several factors including vapor pressure (VP). This investigation reviews the VP of American Contact Dermatitis Society Core Allergens and compares stability predictions based on VP with those established through clinical testing. Standard references were accessed for determining VP in millimeters of mercury and associated temperature in degrees celsius. If multiple values were listed, VP at temperatures that most approximate indoor storage conditions (20°C and 25°C) were chosen. For mixes, the individual component with the highest VP was chosen as the overall VP, assuming that the most volatile substance would evaporate first. Antigens were grouped into low (≤0.001 mm Hg), moderate (0.001 mm Hg), and high (≥1 mm Hg) volatility using arbitrary cutoff values. This review is consistent with previously reported data on formaldehyde, acrylates, and fragrance material instability. Given lack of testing data, VP can be useful in predicting patch test compound stability. Measures such as air-tight multidose reagent containers, sealed single-application dispensers, preparation of patches immediately before application, and storage at lower temperatures may remedy some of these issues.

  11. Synthesis of Graphene Nanoribbons by Ambient-Pressure Chemical Vapor Deposition and Device Integration. (United States)

    Chen, Zongping; Zhang, Wen; Palma, Carlos-Andres; Lodi Rizzini, Alberto; Liu, Bilu; Abbas, Ahmad; Richter, Nils; Martini, Leonardo; Wang, Xiao-Ye; Cavani, Nicola; Lu, Hao; Mishra, Neeraj; Coletti, Camilla; Berger, Reinhard; Klappenberger, Florian; Kläui, Mathias; Candini, Andrea; Affronte, Marco; Zhou, Chongwu; De Renzi, Valentina; Del Pennino, Umberto; Barth, Johannes V; Räder, Hans Joachim; Narita, Akimitsu; Feng, Xinliang; Müllen, Klaus


    Graphene nanoribbons (GNRs), quasi-one-dimensional graphene strips, have shown great potential for nanoscale electronics, optoelectronics, and photonics. Atomically precise GNRs can be "bottom-up" synthesized by surface-assisted assembly of molecular building blocks under ultra-high-vacuum conditions. However, large-scale and efficient synthesis of such GNRs at low cost remains a significant challenge. Here we report an efficient "bottom-up" chemical vapor deposition (CVD) process for inexpensive and high-throughput growth of structurally defined GNRs with varying structures under ambient-pressure conditions. The high quality of our CVD-grown GNRs is validated by a combination of different spectroscopic and microscopic characterizations. Facile, large-area transfer of GNRs onto insulating substrates and subsequent device fabrication demonstrate their promising potential as semiconducting materials, exhibiting high current on/off ratios up to 6000 in field-effect transistor devices. This value is 3 orders of magnitude higher than values reported so far for other thin-film transistors of structurally defined GNRs. Notably, on-surface mass spectrometry analyses of polymer precursors provide unprecedented evidence for the chemical structures of the resulting GNRs, especially the heteroatom doping and heterojunctions. These results pave the way toward the scalable and controllable growth of GNRs for future applications.

  12. Solid state phase transition and vapor pressure studies in ammonium nitrate-potassium nitrate binary system (United States)

    Chien, Wen-Ming

    The solid-state phase transitions in ammonium nitrate (NH4NO 3) and potassium nitrate (KNO3) solid solutions and the equilibrium NH4NO3-KNO3 (AN-KN) phase diagram have been determined. The phase transitions and phase diagram were determined by using the differential scanning calorimetry (DSC) and high temperature X-ray diffractometry. Samples of several different compositions were made for these analyses in a special "Dry Room" with very low humidity. In the X-ray diffraction experiments, the samples were heated on Pt-Rh strip and LaB6 or Si was added for internal calibration. Equilibrium phase diagram was also calculated by using the "FactSage" computer program. A single (AN III) phase region without any phase transitions between 293 to 373 K was observed for compositions between 5 to 25wt% KNO3 in NH4NO3 that is critical for air bag gas generators. The higher temperature KNO3 (KN I) phase has a wide stability range, from 100%KNO3 to 20%KNO3 solution. There is one eutectic, two eutectoids, and two peritectoids in this phase diagram. Two newly discovered solid-state phases were found in the mid-composition range of AN-KN solid solutions. Details of phase equilibria and lattice expansions during heating have been determined. Phase diagram calculations show a reasonable match of the phase boundaries. The total vapor pressures as well as the average molecular weights of pure ammonium nitrate and 16% KNO3 solid solution were measured at various temperatures by the torsion-Knudsen effusion method. The partial pressures of NH4NO3 (PNH4NO 3), NH3 (PNH3), and HNO3 (PHNO 3) have also been determined.

  13. Scavenging dissolved oxygen via acoustic droplet vaporization. (United States)

    Radhakrishnan, Kirthi; Holland, Christy K; Haworth, Kevin J


    Acoustic droplet vaporization (ADV) of perfluorocarbon emulsions has been explored for diagnostic and therapeutic applications. Previous studies have demonstrated that vaporization of a liquid droplet results in a gas microbubble with a diameter 5-6 times larger than the initial droplet diameter. The expansion factor can increase to a factor of 10 in gassy fluids as a result of air diffusing from the surrounding fluid into the microbubble. This study investigates the potential of this process to serve as an ultrasound-mediated gas scavenging technology. Perfluoropentane droplets diluted in phosphate-buffered saline (PBS) were insonified by a 2 MHz transducer at peak rarefactional pressures lower than and greater than the ADV pressure amplitude threshold in an in vitro flow phantom. The change in dissolved oxygen (DO) of the PBS before and after ADV was measured. A numerical model of gas scavenging, based on conservation of mass and equal partial pressures of gases at equilibrium, was developed. At insonation pressures exceeding the ADV threshold, the DO of air-saturated PBS decreased with increasing insonation pressures, dropping as low as 25% of air saturation within 20s. The decrease in DO of the PBS during ADV was dependent on the volumetric size distribution of the droplets and the fraction of droplets transitioned during ultrasound exposure. Numerically predicted changes in DO from the model agreed with the experimentally measured DO, indicating that concentration gradients can explain this phenomenon. Using computationally modified droplet size distributions that would be suitable for in vivo applications, the DO of the PBS was found to decrease with increasing concentrations. This study demonstrates that ADV can significantly decrease the DO in an aqueous fluid, which may have direct therapeutic applications and should be considered for ADV-based diagnostic or therapeutic applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Studies in graphene growth and processing using atmospheric pressure chemical vapor deposition (United States)

    Merrell, Andrew Nephi

    This dissertation focuses on graphene, a promising two-dimensional, carbon material with many favorable electronic properties. The prospect of implementing graphene into a wide variety of potential device applications is enticing, but many factors stand in the way before this goal is realized. Atmospheric pressure chemical vapor deposition (APCVD) is a graphene production method that may be compatible with large-scale growth. Motivated by the need to more fully understand APCVD growth of graphene, a system is constructed, and several studies are carried out. Specifically, a detailed study is presented which involves the effects of hydrogen and contaminant oxygen in APCVD-grown graphene. The research shows that hydrogen is an important factor to control during the cooling stage of APCVD, as it has a direct effect on the formation of oxides on the copper foil (copper is used as the catalyst for graphene growth in APCVD). It is also determined that hydrogen, as well as the reaction chamber, play an important role in the formation of SiO2 nanoparticles, which accumulate on the copper surface during graphene growth. Methods for patterning and processing graphene are also explored in this dissertation, as such methods are crucial in the realization of graphene-based devices. The method of e-beam assisted metal deposition used in conjunction with masked-CVD growth is proposed as an effective alternative to conventional processing methods such as photolithography and electron-beam lithography. The proposed methods have several advantages, which pave the way for lowering graphene/metal contact resistance, and preserving the intrinsic properties of graphene during device fabrication.

  15. On-line coating of glass with tin oxide by atmospheric pressure chemical vapor deposition.

    Energy Technology Data Exchange (ETDEWEB)

    Allendorf, Mark D.; Sopko, J.F. (PPF Industries, Pittsburgh, PA); Houf, William G.; Chae, Yong Kee; McDaniel, Anthony H.; Li, M. (PPF Industries, Pittsburgh, PA); McCamy, J.W. (PPF Industries, Pittsburgh, PA)


    Atmospheric pressure chemical vapor deposition (APCVD) of tin oxide is a very important manufacturing technique used in the production of low-emissivity glass. It is also the primary method used to provide wear-resistant coatings on glass containers. The complexity of these systems, which involve chemical reactions in both the gas phase and on the deposition surface, as well as complex fluid dynamics, makes process optimization and design of new coating reactors a very difficult task. In 2001 the U.S. Dept. of Energy Industrial Technologies Program Glass Industry of the Future Team funded a project to address the need for more accurate data concerning the tin oxide APCVD process. This report presents a case study of on-line APCVD using organometallic precursors, which are the primary reactants used in industrial coating processes. Research staff at Sandia National Laboratories in Livermore, CA, and the PPG Industries Glass Technology Center in Pittsburgh, PA collaborated to produce this work. In this report, we describe a detailed investigation of the factors controlling the growth of tin oxide films. The report begins with a discussion of the basic elements of the deposition chemistry, including gas-phase thermochemistry of tin species and mechanisms of chemical reactions involved in the decomposition of tin precursors. These results provide the basis for experimental investigations in which tin oxide growth rates were measured as a function of all major process variables. The experiments focused on growth from monobutyltintrichloride (MBTC) since this is one of the two primary precursors used industrially. There are almost no reliable growth-rate data available for this precursor. Robust models describing the growth rate as a function of these variables are derived from modeling of these data. Finally, the results are used to conduct computational fluid dynamic simulations of both pilot- and full-scale coating reactors. As a result, general conclusions are

  16. Monitoring the Stability of Perfluorocarbon Nanoemulsions by Cryo-TEM Image Analysis and Dynamic Light Scattering.

    Directory of Open Access Journals (Sweden)

    Christoph Grapentin

    Full Text Available Perfluorocarbon nanoemulsions (PFC-NE are disperse systems consisting of nanoscale liquid perfluorocarbon droplets stabilized by an emulsifier, usually phospholipids. Perfluorocarbons are chemically inert and non-toxic substances that are exhaled after in vivo administration. The manufacture of PFC-NE can be done in large scales by means of high pressure homogenization or microfluidization. Originally investigated as oxygen carriers for cases of severe blood loss, their application nowadays is more focused on using them as marker agents in 19F Magnetic Resonance Imaging (19F MRI. 19F is scarce in organisms and thus PFC-NE are a promising tool for highly specific and non-invasive imaging of inflammation via 19F MRI. Neutrophils, monocytes and macrophages phagocytize PFC-NE and subsequently migrate to inflamed tissues. This technique has proven feasibility in numerous disease models in mice, rabbits and mini pigs. The translation to clinical trials in human needs the development of a stable nanoemulsion whose droplet size is well characterized over a long storage time. Usually dynamic light scattering (DLS is applied as the standard method for determining particle sizes in the nanometer range. Our study uses a second method, analysis of transmission electron microscopy images of cryo-fixed samples (Cryo-TEM, to evaluate stability of PFC-NE in comparison to DLS. Four nanoemulsions of different composition are observed for one year. The results indicate that DLS alone cannot reveal the changes in particle size, but can even mislead to a positive estimation of stability. The combination with Cryo-TEM images gives more insight in the particulate evolution, both techniques supporting one another. The study is one further step in the development of analytical tools for the evaluation of a clinically applicable perfluorooctylbromide nanoemulsion.

  17. Densities and vapor pressures of mixed-solvent desiccant systems containing {l_brace}glycol (diethylene, or triethylene, or tetraethylene glycol) + salt (magnesium chloride) + water{r_brace}

    Energy Technology Data Exchange (ETDEWEB)

    Chen Shangyi [R and D Center for Membrane Technology, Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); Soriano, Allan N. [R and D Center for Membrane Technology, Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); School of Chemical Engineering and Chemistry, Mapua Institute of Technology, Manila 1002 (Philippines); Li Menghui, E-mail: [R and D Center for Membrane Technology, Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China)


    In this present work, new experimental data for density and vapor pressure of the mixed-solvent desiccant systems containing {l_brace}(40.0 wt%) glycol + salt + water{r_brace} were reported for temperatures up to 343.15 K at normal atmospheric condition. The considered glycols were diethylene, triethylene, and tetraethylene glycol; and the salt is magnesium chloride (wt% = 4.0, 9.0, and 16.0). The density and vapor pressure were presented as functions of temperature and compositions. An empirical equation was used to correlate the temperature and compositional dependence of the present density data and a model based on the mean spherical approximation for aqueous electrolyte solutions incorporating the pseudo-solvent approach was used to represent the measured vapor pressure as functions of temperature and composition. Satisfactory results were obtained for both density and vapor pressure calculations.

  18. GOZCARDS Source Water Vapor 1 month L3 10 degree Zonal Means on a Vertical Pressure Grid V1 (GozSmlpH2O) at GES DISC (United States)

    National Aeronautics and Space Administration — The GOZCARDS Source Data for Water Vapor 1 month L3 10 degree Zonal Averages on a Vertical Pressure Grid product (GozSmlpH2O) contains zonal means and related...

  19. Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics

    Directory of Open Access Journals (Sweden)

    A. M. Makarieva


    Full Text Available Phase transitions of atmospheric water play a ubiquitous role in the Earth's climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric pressure through the mass removal of water from the gas phase with a simultaneous account of the latent heat release. Building from fundamental physical principles we show that condensation is associated with a decline in air pressure in the lower atmosphere. This decline occurs up to a certain height, which ranges from 3 to 4 km for surface temperatures from 10 to 30 °C. We then estimate the horizontal pressure differences associated with water vapor condensation and find that these are comparable in magnitude with the pressure differences driving observed circulation patterns. The water vapor delivered to the atmosphere via evaporation represents a store of potential energy available to accelerate air and thus drive winds. Our estimates suggest that the global mean power at which this potential energy is released by condensation is around one per cent of the global solar power – this is similar to the known stationary dissipative power of general atmospheric circulation. We conclude that condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics.

  20. A triblock fluorous surfactant as a specific gelator for perfluorocarbons. (United States)

    Gan, Jiaan; El Bakkari, Mounir; Belin, Colette; Margottin, Chrystèle; Godard, Pascale; Pozzo, Jean-Luc; Vincent, Jean-Marc


    The fluorinated double-tailed triblock surfactant 1-Na represents a new type of gelator for perfluorocarbons which can gelate at low concentration (1.5 wt%) both bromoperfluorooctane and perfluorodecalin, two of the most appealing perfluorinated fluids for pharmaceutical applications.

  1. Isobaric low pressure vapor-liquid equilibrium data for the binary system monochloroacetic acid + dichloroacetic acid

    NARCIS (Netherlands)

    Londono, A.; Jongmans, Mark; Schuur, Boelo; de Haan, A.B.


    Isobaric vapor–liquid equilibrium (VLE) data for the binary system monochloroacetic acid + dichloroacetic acid have been measured at 5, 7.5, and 10 kPa. The VLE data measured in this work is thermodynamically consistent according to the Herington area method. The non-ideal behavior in the vapor

  2. Studies on micro-structures at vapor-liquid interfaces of film boiling on hot liquid surface at arriving of a shock pressure

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Akira; Lee, S. [Tokyo Inst. of Tech. (Japan)


    In vapor explosions, a pressure wave (shock wave) plays a fundamental role in the generation, propagation and escalation of the explosion. Transient volume change by rapid heat flow from a high temperature liquid to a low temperature volatile one and phase change generate micro-scale flow and the pressure wave. One of key issues for the vapor explosion is to make clear the mechanism to support the explosive energy release from hot drop to cold liquid. According to our observations by an Image Converter Camera, growth rate of vapor film around a hot tin drop became several times higher than that around a hot Platinum tube at the same conditions when a pressure pulse collapsed the film. The thermally induced fragmentation was followed by the explosive growth rate of the hot drop. In the previous report, we have proposed that the interface instability and fragmentation model in which the fine Taylor instability of vapor-liquid interface at the collapsing and re-growth phase of vapor film and the instability induced by the high pressure spots at the drop surface were assumed. In this study, the behavior of the vapor-liquid interface region at arrival of a pressure pulse was investigated by the CIPRIS code which is able to simulate dynamics of transient multi-phase interface regions. It is compared with the observation results. Through detailed investigations of these results, the mechanisms of the thermal fragmentation of single drop are discussed. (J.P.N.)

  3. Characteristics of low vapor pressure oil ignition developed with irradiation of mega hertz level ultrasonic

    Energy Technology Data Exchange (ETDEWEB)

    Takuya Fuse; Yasuki Hirota; Noriyuki Kobayashi; Masanobu Hasatani; Yoshio Tanaka [Nagoya University, Nagoya (Japan). Department of Energy Engineering and Science


    In liquid fuel vaporizing type combustor for civil use, large amount of the electric power is consumed in pre-heating of fuel vaporizer during a standby period. Reduction of consumed power in pre-heating is regarded as important to develop a performance of the vaporizing type combustor from the viewpoint of energy saving. We proposed the oil combustion system using the MHz-ultrasonic atomizing method without the preheating process. In this work, we manufactured kerosene pre-vaporizing combustor with ultrasonic oscillator which had frequency of 1.7 MHz. Low CO and NOx emission had been already achieved with manufactured combustor by authors in 2002. Aiming to investigate fundamental characteristics of the ignition process with ultrasonic atomizing, the ignition time requirement was measured and the flame luminescence was detected with spectroscopic analysis in order to consider the mixing state on pre-mixing combustor by judging differences of the flame luminescence. As the results, ultrasonic atomizing method was very effective for vaporization of kerosene. But heat release rate of only 0.54 kW was obtained with input power of 33 W because the effect of the sound absorption was not negligible. The time requirement for the ignition was influenced by an equivalence ratio and balance between primary air flow rate and secondary one. Especially, the ignition time had different tendencies between fuel rich and fuel lean condition. With flow visualization, it was clarified that probability of the ignition depended on a difference of flow pattern of the fuel aerosol. 17 refs., 12 figs., 1 tab.

  4. High-pressure vapor-liquid equilibria for ethylene + 4-methyl-1-pentane and 1-butene + 1-hexene

    Energy Technology Data Exchange (ETDEWEB)

    Laugier, S. [Ecole Nationale Superieure de Chimie et Physique de Bordeaux, Talence (France); Richon, D. [Ecole Nationale Superieure des Mines de Paris, Fontainebleau (France)


    Isothermal vapor-liquid equilibria (VLE) for the ethylene + 4-methyl-1-pentene and 1-butene + 1-hexene binary systems were measured by the static method at several temperatures for pressures in the range (0.3 to 8.5) MPa. Representations of VLE data by the Soave and Peng-Robinson cubic equations of state are compared in both modes: predictive and binary parameter adjustment. As the two binary systems behave almost ideally, there is no significant difference between their representation qualities through both equations of state.

  5. Very Long Single and Few-Walled Boron Nitride Nanotubes via the Pressurized Vapor/Condenser Method (United States)

    Smith, Michael W.; Jordan, Kevin C.; Park, Cheol; Kim, Jae-Woo; Lillehei, Peter T.; Crooks, Roy; Harrison, Joycelyn S.


    A new method for producing long, small diameter, single and few-walled, boron nitride nanotubes (BNNTs) in macroscopic quantities is reported. The pressurized vapor/condenser (PVC) method produces, without catalysts, highly crystalline, very long, small diameter, BNNTs. Palm-sized, cotton-like masses of BNNT raw material were grown by this technique and spun directly into centimeters-long yarn. Nanotube lengths were observed to be 100 times that of those grown by the most closely related method. Self-assembly and growth models for these long BNNTs are discussed.

  6. Oxygen source-oriented control of atmospheric pressure chemical vapor deposition of VO2 for capacitive applications

    Directory of Open Access Journals (Sweden)

    Dimitra Vernardou


    Full Text Available Vanadium dioxides of different crystalline orientation planes have successfully been fabricated by chemical vapor deposition at atmospheric pressure using propanol, ethanol and O2 gas as oxygen sources. The thick a-axis textured monoclinic vanadium dioxide obtained through propanol presented the best electrochemical response in terms of the highest specific discharge capacity of 459 mAh g-1 with a capacitance retention of 97 % after 1000 scans under constant specific current of 2 A g-1. Finally, the electrochemical impedance spectroscopy indicated that the charge transfer of Li+ through the vanadium dioxide / electrolyte interface was easier for this sample enhancing significantly its capacitance performance.

  7. Dual Frequency Acoustic Droplet Vaporization Detection for Medical Imaging (United States)

    Arena, Christopher B.; Novell, Anthony; Sheeran, Paul S.; Puett, Connor; Moyer, Linsey C.; Dayton, Paul A.


    Liquid-filled perfluorocarbon droplets emit a unique acoustic signature when vaporized into to gas-filled microbubbles using ultrasound. Here, we conducted a pilot study in a tissue-mimicking flow phantom to explore the spatial aspects of droplet vaporization and investigate the effects of applied pressure and droplet concentration on image contrast and axial and lateral resolution. Control microbubble contrast agents were used for comparison. A confocal dual-frequency transducer was used to transmit at 8 MHz and passively receive at 1 MHz. Droplet signals were of significantly higher energy than microbubble signals. This resulted in improved signal separation and high contrast-to-tissue ratios (CTR). Specifically, with a peak negative pressure (PNP) of 450 kPa applied at the focus, the CTR of B-mode images was 18.3 dB for droplets and −0.4 for microbubbles. The lateral resolution was dictated by the size of the droplet activation area, with lower pressures resulting in smaller activation areas and improved lateral resolution (0.67 mm at 450 kPa). The axial resolution in droplet images was dictated by the size of the initial droplet and independent of the properties of the transmit pulse (3.86 mm at 450 kPa). In post-processing, time-domain averaging (TDA) improved droplet and microbubble signal separation at high pressures (640 kPa and 700 kPa). Taken together, these results indicate that it is possible to generate high-sensitivity, high-contrast images of vaporization events. In the future, this has the potential to be applied in combination with droplet-mediated therapy to track treatment outcomes or as a stand-alone diagnostic system to monitor the physical properties of the surrounding environment. PMID:26415125

  8. Acoustic Droplet Vaporization in Biology and Medicine

    Directory of Open Access Journals (Sweden)

    Chung-Yin Lin


    Full Text Available This paper reviews the literature regarding the use of acoustic droplet vaporization (ADV in clinical applications of imaging, embolic therapy, and therapeutic delivery. ADV is a physical process in which the pressure waves of ultrasound induce a phase transition that causes superheated liquid nanodroplets to form gas bubbles. The bubbles provide ultrasonic imaging contrast and other functions. ADV of perfluoropentane was used extensively in imaging for preclinical trials in the 1990s, but its use declined rapidly with the advent of other imaging agents. In the last decade, ADV was proposed and explored for embolic occlusion therapy, drug delivery, aberration correction, and high intensity focused ultrasound (HIFU sensitization. Vessel occlusion via ADV has been explored in rodents and dogs and may be approaching clinical use. ADV for drug delivery is still in preclinical stages with initial applications to treat tumors in mice. Other techniques are still in preclinical studies but have potential for clinical use in specialty applications. Overall, ADV has a bright future in clinical application because the small size of nanodroplets greatly reduces the rate of clearance compared to larger contrast agent bubbles and yet provides the advantages of ultrasonographic contrast, acoustic cavitation, and nontoxicity of conventional perfluorocarbon contrast agent bubbles.

  9. Beer Law Constants and Vapor Pressures of HgI2 over HgI2(s,l) (United States)

    Su, Ching-Hua; Zhu, Shen; Ramachandran, N.; Burger, A.


    Optical absorption spectra of the vapor phase over HgI2(s,l) were measured at sample temperatures between 349 and 610 K for wavelengths between 200 and 600 nm. The spectra show the samples sublimed congruently into HGI2 without any observed Hg or I2 absorption spectra. The Beer's Law constants for 15 wavelengths between 200 and 440 nm were derived. From these constants the vapor pressure of HgI2, P, was found to be a function of temperature for the liquid and the solid beta-phases: ln P(atm) = -7700/T(K) + 12.462 (liquid phase) and ln P(atm) = -10150/T(K) + 17.026 (beta-phase). The expressions match the enthalpies of vaporization and sublimation of 15.30 and 20.17 kcal/mole respectively, for the liquid and the beta-phase HgI2. The difference in the enthalpies gives an enthalpy of fusion of 4.87 kcal/mole, and the intersection of the two expressions gives a melting point of 537 K.

  10. Historic and projected changes in vapor pressure deficit suggest a continental-scale drying of the United States atmosphere (United States)

    Ficklin, Darren L.; Novick, Kimberly A.


    Via air temperature increases and relative humidity changes, climate change will modify vapor pressure deficit (VPD), which is an important determinant of water vapor and CO2 exchange between the land surface and atmosphere. VPD is the difference between the water vapor the air can hold at saturation (es) and the actual amount of water vapor (ea). Here we assess changes in VPD, es, and ea in the United States (U.S.) for the recent past (1979-2013) and the future (2065-2099) using gridded, observed climate data and output from general circulation models. Historically, VPD has increased for all seasons, driven by increases in es and declines in ea. The spring, summer, and fall seasons exhibited the largest areal extent of significant increases in VPD, which was largely concentrated in the western and southern portions of the U.S. The changes in VPD stemmed from recent air temperature increases and relative humidity decreases. Projections indicate similar, amplified patterns into the future. For the summer, the general circulation model ensemble median showed a 51% projected increase (quartile range of 39 and 64%) in summer VPD for the U.S., reflecting temperature-driven increases in es but decreases or minimal changes in relative humidity that promotes negligible changes in ea. Using a simple model for plant hydraulic functioning, we also show that in the absence of stomatal acclimation, future changes in VPD can reduce stomatal conductance by 9-51%, which is a magnitude comparable to the expected decline in stomatal conductance from rising CO2.

  11. Determination of Water Vapor Pressure Over Corrosive Chemicals Versus Temperature Using Raman Spectroscopy as Exemplified with 85.5% Phosphoric Acid

    DEFF Research Database (Denmark)

    Rodier, Marion; Li, Qingfeng; Berg, Rolf W.


    A method to determine the water vapor pressure over a corrosive substance was developed and tested with 85.5 ± 0.4% phosphoric acid. The water vapor pressure was obtained at a range of temperatures from ∼25 ℃ to ∼200 ℃ using Raman spectrometry. The acid was placed in an ampoule and sealed...... with a reference gas (either hydrogen or methane) at a known pressure (typically ∼0.5 bar). By comparing the Raman signals from the water vapor and the references, the water pressure was determined as a function of temperature. A considerable amount of data on the vapor pressure of phosphoric acid are available...... in the literature, to which our results could successfully be compared. A record value of the vapor pressure, 3.40 bar, was determined at 210 ℃. The method required a determination of the precise Raman scattering ratios between the substance, water, and the used reference gas, hydrogen or methane. In our case...

  12. Atmospheric pressure chemical vapor deposition (APCVD) grown bi-layer graphene transistor characteristics at high temperature

    KAUST Repository

    Qaisi, Ramy M.


    We report the characteristics of atmospheric chemical vapor deposition grown bilayer graphene transistors fabricated on ultra-scaled (10 nm) high-κ dielectric aluminum oxide (Al2O3) at elevated temperatures. We observed that the drive current increased by >400% as temperature increased from room temperature to 250 °C. Low gate leakage was maintained for prolonged exposure at 100 °C but increased significantly at temperatures >200 °C. These results provide important insights for considering chemical vapor deposition graphene on aluminum oxide for high temperature applications where low power and high frequency operation are required. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. In-situ epitaxial growth of heavily phosphorus doped SiGe by low pressure chemical vapor deposition

    CERN Document Server

    Lee, C J


    We have studied epitaxial crystal growth of Si sub 1 sub - sub x Ge sub x films on silicon substrates at 550 .deg. C by low pressure chemical vapor deposition. In a low PH sub 3 partial pressure region such as below 1.25x10 sup - sup 3 Pa, both the phosphorus and carrier concentrations increased with increasing PH sub 3 partial pressure, but the deposition rate and the Ge fraction remained constant. In a higher PH sub 3 partial pressure region, the deposition rate, the phosphorus concentration, and the carrier concentration decreased, while the Ge fraction increased. These suggest that high surface coverage of phosphorus suppresses both SiH sub 4 and GeH sub 4 adsorption/reactions on the surfaces, and its suppression effect on SiH sub 4 is actually much stronger than on GeH sub 4. In particular, epitaxial crystal growth is largely controlled by surface coverage effect of phosphorus in a higher PH sub 3 partial pressure region.

  14. Modeling vapor liquid equilibrium of ionic liquids + gas binary systems at high pressure with cubic equations of state

    Directory of Open Access Journals (Sweden)

    A. C. D. Freitas


    Full Text Available Ionic liquids (IL have been described as novel environmentally benign solvents because of their remarkable characteristics. Numerous applications of these solvents continue to grow at an exponential rate. In this work, high pressure vapor liquid equilibria for 17 different IL + gas binary systems were modeled at different temperatures with Peng-Robinson (PR and Soave-Redlich-Kwong (SRK equations of state, combined with the van der Waals mixing rule with two binary interaction parameters (vdW-2. The experimental data were taken from the literature. The optimum binary interaction parameters were estimated by minimization of an objective function based on the average absolute relative deviation of liquid and vapor phases, using the modified Simplex algorithm. The solubilities of all gases studied in this work decrease as the temperature increases and increase with increasing pressure. The correlated results were highly satisfactory, with average absolute relative deviations of 2.10% and 2.25% for PR-vdW-2 and SRK-vdW-2, respectively.

  15. [Time lag effect between stem sap flow and photosynthetically active radiation, vapor pressure deficit of Acacia mangium]. (United States)

    Wang, Hua; Zhao, Ping; Cai, Xi-An; Ma, Ling; Rao, Xing-Quan; Zeng, Xiao-Ping


    Based on the measurement of the stem sap flow of Acacia mangium with Granier' s thermal dissipation probe, and the cross-correlation and time serial analysis of the sap flow and corresponding photosynthetically active radiation and vapor pressure deficit, this paper studied the time lag effect between the stem sap flow of A. mangium and the driving factors of the tree canopy transpiration. The results indicated that the main driving factors of the transpiration were photosynthetically active radiation (PAR) and vapor pressure deficit (VPD). Sap flux density (Js) was more dependent on PAR than on VPD, and the dependence was more significant in dry season than in wet season. Sap flow lagged behind PAR but advanced than VPD in both dry and wet seasons. The time lag did not show any significant variation across different size tree individuals, but showed significant variation in different seasons. Time lag effect was not correlated with tree height, diameter at the breast, and canopy size. The time lag between Js and VPD was significantly related to nighttime water recharge in dry season, but reversed in wet season.

  16. Phase-transition thresholds and vaporization phenomena for ultrasound phase-change nanoemulsions assessed via high-speed optical microscopy. (United States)

    Sheeran, Paul S; Matsunaga, Terry O; Dayton, Paul A


    Ultrasonically activated phase-change contrast agents (PCCAs) based on perfluorocarbon droplets have been proposed for a variety of therapeutic and diagnostic clinical applications. When generated at the nanoscale, droplets may be small enough to exit the vascular space and then be induced to vaporize with high spatial and temporal specificity by externally-applied ultrasound. The use of acoustical techniques for optimizing ultrasound parameters for given applications can be a significant challenge for nanoscale PCCAs due to the contributions of larger outlier droplets. Similarly, optical techniques can be a challenge due to the sub-micron size of nanodroplet agents and resolution limits of optical microscopy. In this study, an optical method for determining activation thresholds of nanoscale emulsions based on the in vitro distribution of bubbles resulting from vaporization of PCCAs after single, short (<10 cycles) ultrasound pulses is evaluated. Through ultra-high-speed microscopy it is shown that the bubbles produced early in the pulse from vaporized droplets are strongly affected by subsequent cycles of the vaporization pulse, and these effects increase with pulse length. Results show that decafluorobutane nanoemulsions with peak diameters on the order of 200 nm can be optimally vaporized with short pulses using pressures amenable to clinical diagnostic ultrasound machines.

  17. Method for estimating critical properties of heavy compounds suitable for cubic equations of state and its application to the prediction of vapor pressures

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios; Ioannis, Smirlis; Iakovos, Yakoumis


    Cubic equations of state (EoS) are often used for correlating and predicting phase equilibria. Before extending any EoS to mixtures, reliable vapor-pressure prediction is essential. This requires experimental, if possible, critical temperatures T-c, pressures P-c, and acentric factor omega...... or extensive pure-compound vapor-pressure data which, for heavy and/or complex compounds, are often not available. This work presents a method for estimating T-c, P-c, and omega values for heavy compounds (typically with MW > 130) suitable for vapor-pressure calculations with generalized cubic Eo......S at a single experimental vapor-pressure point (e.g., the normal boiling point). We have employed a modified version of the Peng-Robinson EoS, but we have verified that any cubic EoS yields similar results at least for n-alkanes up to n-octacosane (MW = 394). The method is applied to the prediction of vapor...

  18. Effect of iodine doping in the deposition solution and iodine vapor pressure in the sensitization treatment on the properties of PbSe films (United States)

    Suh, Youngjoon; Suh, Sang-Hee


    Effect of iodine-doping in the deposition solution and iodine vapor pressure during the sensitization process on the morphological, microstructural, electrical, and optical properties of PbSe films was studied. Undoped and iodine-doped PbSe films of polycrystalline particles were coated on thermally oxidized silicon substrates by chemical bath deposition. The PbSe films were oxidized at 380°C for 30 min and then iodinated at different iodine vapor pressures at 380°C for 5 min. When the iodine vapor pressure was below 20 Pa, PbSeO3 was the main phase formed on the surface of PbSe microcrystals for both undoped and iodine-doped films. As the iodine vapor pressure was increased above 20 Pa, Pb3I2O2 and PbI2 phases were formed in both types of films and PbSeO3 disappeared in the undoped film. Only the iodine-doped films showed photo response. The sheet resistance and IR signal-to-noise ratio had maximum values at the iodine vapor pressure of 17.5 Pa in the iodine-doped film. The x-ray diffraction spectra, scanning electron microscopy morphologies, and EDS analyses of the sensitized PbSe films show that the main role of iodine in the sensitization is helping solid-state sintering of PbSe microcrystals which may lead to redistribution of oxygen atoms in the effective atomic sites.

  19. Design of ultrasonically-activatable nanoparticles using low boiling point perfluorocarbons. (United States)

    Sheeran, Paul S; Luois, Samantha H; Mullin, Lee B; Matsunaga, Terry O; Dayton, Paul A


    Recently, an interest has developed in designing biomaterials for medical ultrasonics that can provide the acoustic activity of microbubbles, but with improved stability in vivo and a smaller size distribution for extravascular interrogation. One proposed alternative is the phase-change contrast agent. Phase-change contrast agents (PCCAs) consist of perfluorocarbons (PFCs) that are initially in liquid form, but can then be vaporized with acoustic energy. Crucial parameters for PCCAs include their sensitivity to acoustic energy, their size distribution, and their stability, and this manuscript provides insight into the custom design of PCCAs for balancing these parameters. Specifically, the relationship between size, thermal stability and sensitivity to ultrasound as a function of PFC boiling point and ambient temperature is illustrated. Emulsion stability and sensitivity can be 'tuned' by mixing PFCs in the gaseous state prior to condensation. Novel observations illustrate that stable droplets can be generated from PFCs with extremely low boiling points, such as octafluoropropane (b.p. -36.7 °C), which can be vaporized with acoustic parameters lower than previously observed. Results demonstrate the potential for low boiling point PFCs as a useful new class of compounds for activatable agents, which can be tailored to the desired application. Copyright © 2012 Elsevier Ltd. All rights reserved.


    Fabiilli, Mario L.; Lee, James A.; Kripfgans, Oliver D.; Carson, Paul L.; Fowlkes, J. Brian


    Purpose Ultrasound can be used to release a therapeutic payload encapsulated within a perfluorocarbon (PFC) emulsion via acoustic droplet vaporization (ADV), a process whereby the PFC phase is vaporized and the agent is released. ADV-generated microbubbles have been previously used to selectively occlude blood vessels in vivo. The coupling of ADV-generated drug delivery and occlusion has therapeutically, synergistic potentials. Methods Micron-sized, water-in-PFC-in-water (W1/PFC/W2) emulsions were prepared in a two-step process using perfluoropentane (PFP) or perfluorohexane (PFH) as the PFC phase. Fluorescein or thrombin was contained in the W1 phase. Results Double emulsions containing fluorescein in the W1 phase displayed a 5.7±1.4 fold and 8.2±1.3 fold increase in fluorescein mass flux, as measured using a Franz diffusion cell, after ADV for the PFP and PFH emulsions, respectively. Thrombin was stably retained in four out of five double emulsions. For three out of five formulations tested, the clotting time of whole blood decreased, in a statistically significant manner (p emulsions exposed to ultrasound compared to emulsions not exposed to ultrasound. Conclusions ADV can be used to spatially and temporally control the delivery of water-soluble compounds formulated in PFC double emulsions. Thrombin release could extend the duration of ADV-generated, microbubble occlusions. PMID:20872050

  1. Time variant layer control in atmospheric pressure chemical vapor deposition based growth of graphene

    KAUST Repository

    Qaisi, Ramy M.


    Graphene is a semi-metallic, transparent, atomic crystal structure material which is promising for its high mobility, strength and transparency - potentially applicable for radio frequency (RF) circuitry and energy harvesting and storage applications. Uniform (same number of layers), continuous (not torn or discontinuous), large area (100 mm to 200 mm wafer scale), low-cost, reliable growth are the first hand challenges for its commercialization prospect. We show a time variant uniform (layer control) growth of bi- to multi-layer graphene using atmospheric chemical vapor deposition system. We use Raman spectroscopy for physical characterization supported by electrical property analysis. © 2013 IEEE.

  2. Inflammation Induced by Perfluorocarbon Liquid: Intra- and Postoperative Use

    Directory of Open Access Journals (Sweden)

    Marta S. Figueroa


    Full Text Available Perfluorocarbon liquids (PFCLs are useful and safe surgical tools in vitreoretinal surgery. The use of PFCL as a tamponade has been controversial due to the corneal toxicity, retinal infiltration, and inflammatory reaction in experimental studies. Several authors have studied in humans the anatomical and functional outcome and adverse effects of perfluorocarbon liquids used as short-, medium-, and long-term tamponade. PFCLs develop dispersion a few days after injection and droplets may move into the anterior chamber and cause corneal endothelial damage. When PFCLs are used as postoperative tamponades for more than one week, a foreign-body inflammatory reaction is observed in up to 30% of cases but such a reaction does not induce PVR, and it resolves after removal of PFCLs. Although most clinical studies have found no signs of retinal toxicity such as progressive visual acuity deterioration or macular anatomical changes, few performed ERG or retinal histological analysis.

  3. Determinação da pressão de vapor de compostos orgânicos por cromatografia gasosa Determination of vapor pressure of organic compounds by gas chromatography

    Directory of Open Access Journals (Sweden)

    Fabrício P. Povh


    Full Text Available O conhecimento das pressões de vapor dos compostos naturais e suas propriedades críticas, de grande interesse para a extração supercrítica e impregnação de polímeros pelo processo supercrítico, é imprescindível para se fazer a modelagem termodinâmica do equilíbrio de fases. No entanto, a escassez de dados experimentais desses compostos, devida à alta volatilidade, ou facilidade à degradação em temperaturas baixas, requer a utilização de métodos especiais. Neste trabalho, determinaram-se as pressões de vapor da curcumina, nicotina, d-limoneno, beta-mirceno, citronelal e linalol, através de um método que utiliza medidas de tempo de retenção por cromatografia gasosa. Utilizou-se detector de ionização de chama e coluna em fase estacionária não polar, em condições isotérmicas. O método apresenta vantagens em relação a outros métodos, quanto à rapidez de análise, quantidade e repetibilidade das amostras. Para as determinações das pressões de vapor destes compostos naturais requer-se o conhecimento da temperatura normal de ebulição, ou temperatura de fusão e das pressões de vapor dos homólogos dos compostos analisados.The knowledge of the vapor pressures of natural compounds, as well as their critical properties are of great interest for the application of supercritical extraction and supercritical impregnation dye, and necessary for the thermodynamic modeling of equilibria phase. The scarcity of experimental data for these compounds results from their low volatility or easiness to degrade at low temperatures, therefore, requires the use of special methods. In this work, the vapor pressures of curcumin, nicotine, d-limonene, ß-myrcene, citronellal and linalool were determined through a method based on the retention time in a gas chromatographer column. A flame ionization detector and a column with non-polar stationary phase were used, under isothermal conditions. This method has the advantages of giving

  4. Reduced-Pressure Chemical Vapor Deposition Growth of Isolated Ge Crystals and Suspended Layers on Micrometric Si Pillars. (United States)

    Skibitzki, Oliver; Capellini, Giovanni; Yamamoto, Yuji; Zaumseil, Peter; Schubert, Markus Andreas; Schroeder, Thomas; Ballabio, Andrea; Bergamaschini, Roberto; Salvalaglio, Marco; Miglio, Leo; Montalenti, Francesco


    In this work, we demonstrate the growth of Ge crystals and suspended continuous layers on Si(001) substrates deeply patterned in high aspect-ratio pillars. The material deposition was carried out in a commercial reduced-pressure chemical vapor deposition reactor, thus extending the "vertical-heteroepitaxy" technique developed by using the peculiar low-energy plasma-enhanced chemical vapor deposition reactor, to widely available epitaxial tools. The growth process was thoroughly analyzed, from the formation of small initial seeds to the final coalescence into a continuous suspended layer, by means of scanning and transmission electron microscopy, X-ray diffraction, and μ-Raman spectroscopy. The preoxidation of the Si pillar sidewalls and the addition of hydrochloric gas in the reactants proved to be key to achieve highly selective Ge growth on the pillars top only, which, in turn, is needed to promote the formation of a continuous Ge layer. Thanks to continuum growth models, we were able to single out the different roles played by thermodynamics and kinetics in the deposition dynamics. We believe that our findings will open the way to the low-cost realization of tens of micrometers thick heteroepitaxial layer (e.g., Ge, SiC, and GaAs) on Si having high crystal quality.

  5. Experimental results for hydrocarbon refrigerant vaporization inside brazed plate heat exchangers at high pressure

    DEFF Research Database (Denmark)

    Desideri, Adriano; Ommen, Torben Schmidt; Wronski, Jorrit


    In recent years the interest in small capacity organic Rankine cycle (ORC) power systems for harvesting low qualitywaste thermal energy from industrial processes has been steadily growing. Micro ORC systems are normally equippedwith brazed plate heat exchangers which allows for efficient heat...... transfer with a compact design. An accurate prediction of the heat transfer process characterizing these devices is required from the design phase to the development of modelbased control strategies. The current literature is lacking experimental data and validated correlations for vaporization of organic...... fluids at typical working conditions of ORC systems for low temperature waste heat recovery (WHR) applications. Based on these premises, a novel testrig has been recently designed and built at the Technical University of Denmark to simulate the evaporating condition occurring in a small capacity ORC...

  6. On the Origin of Light Emission in Silicon Rich Oxide Obtained by Low-Pressure Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    M. Aceves-Mijares


    Full Text Available Silicon Rich Oxide (SRO has been considered as a material to overcome the drawbacks of silicon to achieve optical functions. Various techniques can be used to produce it, including Low-Pressure Chemical Vapor Deposition (LPCVD. In this paper, a brief description of the studies carried out and discussions of the results obtained on electro-, cathode-, and photoluminescence properties of SRO prepared by LPCVD and annealed at 1,100°C are presented. The experimental results lead us to accept that SRO emission properties are due to oxidation state nanoagglomerates rather than to nanocrystals. The emission mechanism is similar to Donor-Acceptor decay in semiconductors, and a wide emission spectrum, from 450 to 850 nm, has been observed. The results show that emission is a function of both silicon excess in the film and excitation energy. As a result different color emissions can be obtained by selecting the suitable excitation energy.

  7. Facile Fabrication of Boron-Doped Titania Nanopowders by Atmospheric Pressure Chemical Vapor Synthesis Route and its Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    K. Saberyan


    Full Text Available The Atmospheric Pressure Chemical Vapor Synthesis (APCVS route is a process that can be used for the synthesis of doped-nanocrystalline powders with very small crystallite sizes having a narrow particle size distribution and high purity. In this study, APCVS technique was used to prepare boron-doped titania nanopowders. The effects of temperature, borate flow rate and water flow rate on the amount of doped boron were studied. The resultant powders were characterized by inductively coupled plasma (ICP, X-ray diffraction (XRD, nitrogen adsorption technique (BET, UV-visible DRS spectroscopy, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. The optimum boron precursor flow rate was 80 sccm. The highest amount of doped boron was attained when water flow rate was 900 sccm. In comparison to the pristine TiO2, the boron-doped TiO2 nanoparticles showed blue-shift in band-gap energy of the samples.

  8. Kinetics and dynamics of nanosecond streamer discharge in atmospheric-pressure gas bubble suspended in distilled water under saturated vapor pressure conditions

    KAUST Repository

    Sharma, Ashish


    We perform computational studies of nanosecond streamer discharges generated in helium bubbles immersed in distilled water under atmospheric pressure conditions. The model takes into account the presence of water vapor in the gas bubble for an accurate description of the discharge kinetics. We find that the dynamic characteristics of the streamer discharge are different at low and high positive trigger voltages with the axial streamer evolution dominant for low voltages and a surface hugging mode favored for high voltages. We also find a substantial difference in initiation, transition and evolution stages of discharge for positive and negative trigger voltages with the volumetric distribution of species in the streamer channel much more uniform for negative trigger voltages on account of the presence of multiple streamers. We observe that the presence of water vapor does not affect the breakdown voltage even for oversaturated conditions but significantly influences the composition of dominant species in the trail of the streamer as well as the flux of the dominant species on the bubble surface. © 2016 IOP Publishing Ltd.

  9. Kinetics and dynamics of nanosecond streamer discharge in atmospheric-pressure gas bubble suspended in distilled water under saturated vapor pressure conditions (United States)

    Sharma, Ashish; Levko, Dmitry; Raja, Laxminarayan L.; Cha, Min Suk


    We perform computational studies of nanosecond streamer discharges generated in helium bubbles immersed in distilled water under atmospheric pressure conditions. The model takes into account the presence of water vapor in the gas bubble for an accurate description of the discharge kinetics. We find that the dynamic characteristics of the streamer discharge are different at low and high positive trigger voltages with the axial streamer evolution dominant for low voltages and a surface hugging mode favored for high voltages. We also find a substantial difference in initiation, transition and evolution stages of discharge for positive and negative trigger voltages with the volumetric distribution of species in the streamer channel much more uniform for negative trigger voltages on account of the presence of multiple streamers. We observe that the presence of water vapor does not affect the breakdown voltage even for oversaturated conditions but significantly influences the composition of dominant species in the trail of the streamer as well as the flux of the dominant species on the bubble surface.

  10. Vapor pressures of 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids with long alkyl chains

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Marisa A. A., E-mail:, E-mail: [Centro de Investigação em Química, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven (Netherlands); Coutinho, João A. P. [CICECO, Departamento de Química, Universidade de Aveiro, P-3810-193 Aveiro (Portugal); Santos, Luís M. N. B. F., E-mail:, E-mail: [Centro de Investigação em Química, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)


    This work presents the vapor pressure at several temperatures for the 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide series, [C{sub N/2}C{sub N/2}im][NTf{sub 2}] (N = 14, 16, 18, and 20), measured by a Knudsen effusion method combined with a quartz crystal microbalance. The thermodynamic properties of vaporization of the ionic liquids under study are analysed together with the results obtained previously for the shorter alkyl chain length [C{sub N/2}C{sub N/2}im][NTf{sub 2}] (N = 2, 4, 6, 8, 10, and 12), in order to evaluate the effect of the alkyl side chains of the cation and to get additional insights concerning the nanostructuration of ionic liquids. The symmetry effect is explored, based on the comparison with the asymmetric imidazolium based ionic liquids, [C{sub N-1}C{sub 1}im][NTf{sub 2}]. A trend shift on the thermodynamic properties of vaporization along the alkyl side chains of the extended symmetric ionic liquids, around [C{sub 6}C{sub 6}im][NTf{sub 2}], was detected. An intensification of the odd-even effect was observed starting from [C{sub 6}C{sub 6}im][NTf{sub 2}], with higher enthalpies and entropies of vaporization for the odd numbered ionic liquids, [C{sub 7}C{sub 7}im][NTf{sub 2}] and [C{sub 9}C{sub 9}im][NTf{sub 2}]. Similar, but less pronounced, odd-even effect was found for the symmetric ionic liquids with lower alkyl side chains length, [C{sub N/2}C{sub N/2}im][NTf{sub 2}] (with N = 4, 6, 8, 10, and 12). This effect is related with the predominant orientation of the terminal methyl group of the alkyl chain to the imidazolium ring and their influence in the cation-anion interaction. The same Critical Alkyl length at the hexyl, (C{sub 6}C{sub 1}and C{sub 6}C{sub 6}) was found for both asymmetric and symmetric series indicating that the nanostructuration of the ionic liquids is related with alkyl chain length.

  11. Linking Turgor with ABA Biosynthesis: Implications for Stomatal Responses to Vapor Pressure Deficit across Land Plants1[OPEN (United States)

    McAdam, Scott A.M.; Brodribb, Timothy J.


    Stomatal responses to changes in vapor pressure deficit (VPD) constitute the predominant form of daytime gas-exchange regulation in plants. Stomatal closure in response to increased VPD is driven by the rapid up-regulation of foliar abscisic acid (ABA) biosynthesis and ABA levels in angiosperms; however, very little is known about the physiological trigger for this increase in ABA biosynthesis at increased VPD. Using a novel method of modifying leaf cell turgor by the application of external pressures, we test whether changes in turgor pressure can trigger increases in foliar ABA levels over 20 min, a period of time most relevant to the stomatal response to VPD. We found in angiosperm species that the biosynthesis of ABA was triggered by reductions in leaf turgor, and in two species tested, that a higher sensitivity of ABA synthesis to leaf turgor corresponded with a higher stomatal sensitivity to VPD. In contrast, representative species from nonflowering plant lineages did not show a rapid turgor-triggered increase in foliar ABA levels, which is consistent with previous studies demonstrating passive stomatal responses to changes in VPD in these lineages. Our method provides a new tool for characterizing the response of stomata to water availability. PMID:27208264

  12. Calibrated vapor generator source (United States)

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


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

  13. High-pressure vapor-liquid equilibrium data for CO2-orange peel oil

    Directory of Open Access Journals (Sweden)

    G.R. Stuart


    Full Text Available Recently, there has been a growing interest in fractionating orange peel oil by the use of supercritical carbon dioxide (SCCO2. However, progress in this area has been hindered by the lack of more comprehensive work concerning the phase equilibrium behavior of the SCCO2-orange peel oil system. In this context, the aim of this work is to provide new phase equilibrium data for this system over a wide range of temperatures and pressures, permitting the construction of coexistence PT-xy curves as well as the P-T diagram. The experiments were performed in a high-pressure variable-volume view cell in the temperature range of 50-70ºC from 70 to 135 atm and in the CO2 mass fraction composition range of 0.35-0.98. Based on the experimental phase equilibrium results, appropriate operating conditions can be set for high-pressure fractionation purposes.

  14. Preparation of high-pressure phase boron nitride films by physical vapor deposition

    CERN Document Server

    Zhu, P W; Zhao, Y N; Li, D M; Liu, H W; Zou Guang Tian


    The high-pressure phases boron nitride films together with cubic, wurtzic, and explosive high-pressure phases, were successfully deposited on the metal alloy substrates by tuned substrate radio frequency magnetron sputtering. The percentage of cubic boron nitride phase in the film was about 50% as calculated by Fourier transform infrared measurements. Infrared peak position of cubic boron nitride at 1006.3 cm sup - sup 1 , which is close to the stressless state, indicates that the film has very low internal stress. Transition electron microscope micrograph shows that pure cubic boron nitride phase exits on the surface of the film. The growth mechanism of the BN films was also discussed.

  15. Desenvolvimento de um equipamento para avaliação do efeito do etanol na pressão de vapor e entalpia de vaporização em gasolinas automotivas Development of a device to valuate the effect of ethanol on the vapor pressure and vaporization enthalpy of fuel gasolines

    Directory of Open Access Journals (Sweden)

    Renato Cataluña


    Full Text Available The quality of the gasoline utilized for fueling internal combustion engines with spark ignition is directly affected by the gasoline's properties. Thus, the fuel's properties must be in perfect equilibrium to allow the engine to perform optimally, not only insofar as fuel consumption is concerned, but also in order to reduce the emission of pollutants. Vapor pressure and vaporization enthalpy are important properties of a gasoline determining the fuel's behavior under different operating conditions in internal combustion engines. The study reported here involved the development of a device to determine the vapor pressure and the vaporization enthalpy of formulations containing volumes of 5, 15 and 25% of ethanol in four base gasolines (G1, G2, G3 and G4. The chemical composition of these gasolines was determined using a gas chromatographer equipped with a flame ionization detector (FID.

  16. Heat transport in cold-wall single-wafer low pressure chemical-vapor-deposition reactors

    NARCIS (Netherlands)

    Hasper, A.; Schmitz, J.E.J.; Holleman, J.; Verweij, J.F.


    A model is formulated to understand and predict wafer temperatures in a tungsten low pressure chemical‐vapor‐deposition (LPCVD) single‐wafer cold‐wall reactor equipped with hot plate heating. The temperature control is usually carried out on the hot plate temperature. Large differences can occur

  17. A new method for concentration analysis of bacterial endotoxins in perfluorocarbon (United States)

    Chen, Dan-Dan; Feng, Xiao-Ming; Wang, Chun-Ren; Huang, Qing-Quan; Yang, Zhao-Peng; Meng, Qing-Yuan


    This communication demonstrates the feasibility of the gel-clot method for the analysis of bacterial endotoxins in water extracts of perfluorocarbon which is a water insoluble liquid medical device. Perfluorocarbon (10 mL) was shaken with 10mL water for 15 min at 2000 r/min and the endotoxin present was extracted to the aqueous phase without interference inhibition/enhancement of the product and the recovery of endotoxin added to perfluorocarbon was determined. A validation study confirmed that endotoxins presented in perfluorocarbon pass over into the aqueous phase at concentrations of 20, 10 and 5 EU/mL with recoveries from 86.8% to 96.8%. Therefore, the gel-clot test is suitable for detecting bacterial endotoxins in perfluorocarbon which is a water insoluble medical device.

  18. Undoped and in-situ B doped GeSn epitaxial growth on Ge by atmospheric pressure-chemical vapor deposition

    DEFF Research Database (Denmark)

    Vincent, B.; Gencarelli, F.; Bender, H.


    In this letter, we propose an atmospheric pressure-chemical vapor deposition technique to grow metastable GeSn epitaxial layers on Ge. We report the growth of defect free fully strained undoped and in-situ B doped GeSn layers on Ge substrates with Sit contents up to 8%. Those metastable layers stay...

  19. 42 CFR 84.163 - Man test for gases and vapors; Type C supplied-air respirators, demand and pressure-demand... (United States)


    ... 42 Public Health 1 2010-10-01 2010-10-01 false Man test for gases and vapors; Type C supplied-air respirators, demand and pressure-demand classes; test requirements. 84.163 Section 84.163 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF...

  20. Identifying Liquid-Gas System Misconceptions and Addressing Them Using a Laboratory Exercise on Pressure-Temperature Diagrams of a Mixed Gas Involving Liquid-Vapor Equilibrium (United States)

    Yoshikawa, Masahiro; Koga, Nobuyoshi


    This study focuses on students' understandings of a liquid-gas system with liquid-vapor equilibrium in a closed system using a pressure-temperature ("P-T") diagram. By administrating three assessment questions concerning the "P-T" diagrams of liquid-gas systems to students at the beginning of undergraduate general chemistry…

  1. The gas phase emitter effect of lanthanum within ceramic metal halide lamps and its dependence on the La vapor pressure and operating frequency (United States)

    Ruhrmann, C.; Hoebing, T.; Bergner, A.; Groeger, S.; Denissen, C.; Suijker, J.; Awakowicz, P.; Mentel, J.


    The gas phase emitter effect increases the lamp lifetime by lowering the work function and, with it, the temperature of the tungsten electrodes of metal halide lamps especially for lamps in ceramic vessels due to their high rare earth pressures. It is generated by a monolayer on the electrode surface of electropositive atoms of certain emitter elements, which are inserted into the lamp bulb by metal iodide salts. They are vaporized, dissociated, ionized, and deposited by an emitter ion current onto the electrode surface within the cathodic phase of lamp operation with a switched-dc or ac-current. The gas phase emitter effect of La and the influence of Na on the emitter effect of La are studied by spatially and phase-resolved pyrometric measurements of the electrode tip temperature, La atom, and ion densities by optical emission spectroscopy as well as optical broadband absorption spectroscopy and arc attachment images by short time photography. An addition of Na to the lamp filling increases the La vapor pressure within the lamp considerably, resulting in an improved gas phase emitter effect of La. Furthermore, the La vapor pressure is raised by a heating of the cold spot. In this way, conditions depending on the La vapor pressure and operating frequency are identified, at which the temperature of the electrodes becomes a minimum.

  2. The gas phase emitter effect of lanthanum within ceramic metal halide lamps and its dependence on the La vapor pressure and operating frequency

    Energy Technology Data Exchange (ETDEWEB)

    Ruhrmann, C.; Hoebing, T.; Bergner, A.; Groeger, S.; Awakowicz, P.; Mentel, J. [Electrical Engineering and Plasma Technology, Ruhr University Bochum, D-44780 Bochum (Germany); Denissen, C.; Suijker, J. [Philips Lighting, Category Professional Lamps, P.O. Box 80020, NL-5600JM Eindhoven (Netherlands)


    The gas phase emitter effect increases the lamp lifetime by lowering the work function and, with it, the temperature of the tungsten electrodes of metal halide lamps especially for lamps in ceramic vessels due to their high rare earth pressures. It is generated by a monolayer on the electrode surface of electropositive atoms of certain emitter elements, which are inserted into the lamp bulb by metal iodide salts. They are vaporized, dissociated, ionized, and deposited by an emitter ion current onto the electrode surface within the cathodic phase of lamp operation with a switched-dc or ac-current. The gas phase emitter effect of La and the influence of Na on the emitter effect of La are studied by spatially and phase-resolved pyrometric measurements of the electrode tip temperature, La atom, and ion densities by optical emission spectroscopy as well as optical broadband absorption spectroscopy and arc attachment images by short time photography. An addition of Na to the lamp filling increases the La vapor pressure within the lamp considerably, resulting in an improved gas phase emitter effect of La. Furthermore, the La vapor pressure is raised by a heating of the cold spot. In this way, conditions depending on the La vapor pressure and operating frequency are identified, at which the temperature of the electrodes becomes a minimum.

  3. Nanocell with a pressure-controlled Rb atomic vapor column thickness: Critical influence of the thickness on optical processes (United States)

    Sargsyan, A.; Amiryan, A.; Cartaleva, S.; Sarkisyan, D.


    A new device is designed: it consists of a nanocell (NC) filled with Rb atom vapors and placed in a vacuum chamber. When the pressure in the chamber changes in the range 0-1 atm, the NC thickness is smoothly varied in the range L = 140-1700 nm, which is caused by the pressure-induced deformation of thin garnet windows in the chamber. The pressure dependence has excellent reproducibility even after many hundreds of cycles of letting in of air and its complete pumping out from the chamber. The accuracy of setting required thickness L is much better than in the wedge-gap NCs to be moved mechanically that were used earlier. The processes of Faraday rotation (FR) of a polarization plane, resonance absorption, and fluorescence are studied using the D 1-line narrow-band continuous laser radiation when the thickness changes from L = λ/2 (398 nm) to L = 2λ (1590 nm) at a step λ/2. The FR signal is shown to be maximal at L = λ/2 and 3λ/2 and to have the minimum spectral width (≈60 MHz). At L = λ and 2λ, the FR signal is minimal and has the maximum spectral width (≈200 MHz). The resonance absorption demonstrates the same oscillating behavior; however, the effect in the case of FR is much more pronounced. The oscillating effect is absent for resonance fluorescence: its spectral width and amplitude increase monotonically with L. The detected effects are explained and possible applications are noted.

  4. Behavior of ultrasounds crossing perfluorocarbon liquids and random propagation times. (United States)

    Lacaze, Bernard


    Random propagation times are able to model waves attenuation and velocity. It is true for electromagnetic waves (light, radar, guided propagation) and also for acoustics and ultrasounds (acoustics for high frequencies). About the latter, it can be shown that stable probability laws are well-fitted for frequencies up to dozens of megahertz in numerous cases. Nowadays, medical applications are performed using propagation through perfluorocarbon (PFC). Experiments were done to measure attenuations and phase changes. Using these results, this paper addresses the question to know if stable probability laws can be used to characterize the propagation of ultrasounds through PFC liquids. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Asymmetric growth of bilayer graphene on copper enclosures using low-pressure chemical vapor deposition. (United States)

    Fang, Wenjing; Hsu, Allen L; Song, Yi; Birdwell, Anthony G; Amani, Matin; Dubey, Madan; Dresselhaus, Mildred S; Palacios, Tomás; Kong, Jing


    In this work, we investigated the growth mechanisms of bilayer graphene on the outside surface of Cu enclosures at low pressures. We observed that the asymmetric growth environment of a Cu enclosure can yield a much higher (up to 100%) bilayer coverage on the outside surface as compared to the bilayer growth on a flat Cu foil, where both sides are exposed to the same growth environment. By simultaneously examining the graphene films grown on both the outside and inside surfaces of the Cu enclosure, we find that carbon can diffuse from the inside surface to the outside via exposed copper regions on the inside surface. The kinetics of this process are examined by coupling the asymmetric growth between the two surfaces through a carbon diffusion model. Finally, using these results, we show that the coverage of bilayer graphene can be tuned simply by changing the thickness of the Cu foil, further confirming our model of carbon delivery through the Cu foil.

  6. Isosteric Vapor Pressure – Temperature Data for Water Sorption in Hardened Cement Paste: Enthalpy, Entropy and Sorption Isotherms at Different Temperatures

    DEFF Research Database (Denmark)

    Radjy, Fariborz; Sellevold, Erik J.; Hansen, Kurt Kielsgaard

    . The accuracies for pressure, enthalpy and entropy are found to be 0.5% or less. PART II: The TPA-system has been used to generate water vapor pressure – temperature data for room temperature – and steam cured hardened cement pastes as well as porous vycor glass. The moisture contents range from saturated to dry...... and the temperatures range from 2 to 95 °C, differing for the specimen types. The data has been analyzed to yield differential enthalpy and entropy of adsorption, as well as the dependence of the relative vapor pressure on temperature at various constant moisture contents. The implications for the coefficient...... of thermal expansion have been explored....

  7. Enhancement of ultrasound reflectivity depends on the specific perfluorocarbons utilized to formulate nanoparticle emulsion contrast agents (United States)

    Marsh, Jon N.; Hall, Christopher S.; Scott, Michael J.; Fuhrhop, Ralph J.; Gaffney, Patrick J.; Wickline, Samuel A.; Lanza, Gregory M.


    A nongaseous, ligand-targeted perfluorocarbon nanoparticle emulsion has been developed which can acoustically enhance the presence of molecular epitopes on tissue surfaces. We demonstrate the impact of incorporating perfluorocarbons with specific phase velocities into the emulsions on the acoustic reflectivity of plasma clots targeted using these nanoparticles. Porcine plasma clots were targeted in vitro with specific perfluorocarbon emulsions using anti-fibrin antibody solution (NIB 5F3). Five perfluorocarbons were investigated: perfluorohexane, perfluorooctyl-bromide, perfluorooctane, perfluorodichlorooctane, and perfluorodecalin. Ultrasonic backscatter (17 - 35 MHz) was measured at the front surface of the clots. Backscatter enhancement was determined by comparison with untreated clots. The magnitude of enhancement depended on the perfluorocarbon emulsion used. Perfluorohexane and perfluorooctane exhibited the greatest enhancement relative to untreated clots (23 dB) and perfluorodecalin the least (18 dB), consistent with predictions from a simple acoustic transmission-line model. We conclude that targeted, nongaseous perfluorocarbon contrast agents can significantly increase the sensitivity of ultrasonic detection of low-scattering biological media, and that further optimization of these contrast agents can be realized by judicious choice of the emulsified perfluorocarbon.

  8. Urban Pollutant Transport and Infiltration into Buildings Using Perfluorocarbon Tracers (United States)

    Matthews, James C.; Bacak, Asan; Khan, M. Anwar H.; Wright, Matthew D.; Priestley, Michael; Martin, Damien; Percival, Carl J.; Shallcross, Dudley E.


    People spend the majority of their time indoors and therefore the quality of indoor air is worthy of investigation; indoor air quality is affected by indoor sources of pollutants and from pollutants entering buildings from outdoors. In this study, unique perfluorocarbon tracers were released in five experiments at a 100 m and ~2 km distance from a large university building in Manchester, UK and tracer was also released inside the building to measure the amount of outdoor material penetrating into buildings and the flow of material within the building itself. Air samples of the tracer were taken in several rooms within the building, and a CO2 tracer was used within the building to estimate air-exchange rates. Air-exchange rates were found to vary between 0.57 and 10.90 per hour. Indoor perfluorocarbon tracer concentrations were paired to outdoor tracer concentrations, and in-out ratios were found to vary between 0.01 and 3.6. The largest room with the lowest air-exchange rate exhibited elevated tracer concentrations for over 60 min after the release had finished, but generally had the lowest concentrations, the room with the highest ventilation rates had the highest concentration over 30 min, but the peak decayed more rapidly. Tracer concentrations indoors compared to outdoors imply that pollutants remain within buildings after they have cleared outside, which must be considered when evaluating human exposure to outdoor pollutants. PMID:28230812

  9. High Temperature Nanocomposites For Nuclear Thermal Propulsion and In-Space Fabrication by Hyperbaric Pressure Laser Chemical Vapor Deposition (United States)

    Maxwell, J. L.; Webb, N. D.; Espinoza, M.; Cook, S.; Houts, M.; Kim, T.

    Nuclear Thermal Propulsion (NTP) is an indispensable technology for the manned exploration of the solar system. By using Hyperbaric Pressure Laser Chemical Vapor Deposition (HP-LCVD), the authors propose to design and build a promising next-generation fuel element composed of uranium carbide UC embedded in a latticed matrix of highly refractory Ta4HfC5 for an NTP rocket capable of sustaining temperatures up to 4000 K, enabling an Isp of up to 1250 s. Furthermore, HP-LCVD technology can also be harnessed to enable 3D rapid prototyping of a variety of materials including metals, ceramics and composites, opening up the possibility of in-space fabrication of components, replacement parts, difficult-to-launch solar sails and panels and a variety of other space structures. Additionally, rapid prototyping with HP-LCVD makes a feasible "live off the land" strategy of interplanetary and interstellar exploration ­ the precursors commonly used in the technology are found, often in abundance, on other solar system bodies either as readily harvestable gas (e.g. methane) or as a raw material that could be converted into a suitable precursor (e.g. iron oxide into ferrocene on Mars).

  10. Activity coefficients and free energies of nonionic mixed surfactant solutions from vapor-pressure and freezing-point osmometry. (United States)

    MacNeil, Jennifer A; Ray, Gargi Basu; Leaist, Derek G


    The thermodynamic properties of mixed surfactant solutions are widely investigated, prompted by numerous practical applications of these systems and by interest in molecular association and self-organization. General techniques for measuring thermodynamic activities, such as isopiestic equilibration, are well-established for multicomponent solutions. Surprisingly, these techniques have not yet been applied to mixed surfactant solutions, despite the importance of the free energy for micelle stability. In this study, equations are developed for the osmotic coefficients of solutions of nonionic surfactant A + nonionic surfactant B. A mass-action model is used, with virial equations for the activity coefficients of the micelles and free surfactant monomer species. The equations are fitted to osmotic coefficients of aqueous decylsulfobetaine + dodecylsulfobetaine solutions measured by vapor-pressure and freezing-point osmometry. Equilibrium constants for mixed-micelle formation are calculated from the free monomer concentrations at the critical micelle concentrations. The derived activity coefficients of the micelles and free monomers indicate large departures from ideal solution behavior, even for dilute solutions of the surfactants. Stoichiometric activity coefficients of the total surfactant components are evaluated by Gibbs-Duhem integration of the osmotic coefficients. Relatively simple colligative property measurements hold considerable promise for free energy studies of multicomponent surfactant solutions. © 2011 American Chemical Society

  11. Quantitative relationships for the prediction of the vapor pressure of some hydrocarbons from the van der Waals molecular surface

    Directory of Open Access Journals (Sweden)

    Olariu Tudor


    Full Text Available A quantitative structure - property relationship (QSPR modeling of vapor pressure at 298.15 K, expressed as log (VP / Pa was performed for a series of 84 hydrocarbons (63 alkanes and 21 cycloalkanes using the van der Waals (vdW surface area, SW/Å2, calculated by the Monte Carlo method, as the molecular descriptor. The QSPR model developed from the subset of 63 alkanes (C1-C16, deemed as the training set, was successfully used for the prediction of the log (VP / Pa values of the 21 cycloalkanes, which was the external prediction (test subset. A QSPR model was also developed for a series composed of all 84 hydrocarbons. Both QSPR models were statistically tested for their ability to fit the data and for prediction. The results showed that the vdW molecular surface used as molecular descriptor (MD explains the variance of the majority of the log (VP / Pa values in this series of 84 hydrocarbons. This MD describes very well the intermolecular forces that hold neutral molecules together. The clear physical meaning of the molecular surface values, SW/Å2, could explain the success of the QSPR models obtained with a single structural molecular descriptor.

  12. Suppression of Graphene Nucleation by Turning Off Hydrogen Supply Just before Atmospheric Pressure Chemical Vapor Deposition Growth

    Directory of Open Access Journals (Sweden)

    Seiya Suzuki


    Full Text Available To exploit the extraordinary property of graphene in practical electrical and optical devices, it is necessary to produce large-sized, single-crystal graphene. Atmospheric pressure chemical vapor deposition (APCVD on polycrystalline Cu surface is a promising scalable route of graphene synthesis but the unavoidable multiple nucleation limits their reachable domain size. Here, we report that effective suppression of nucleation was achieved by only turning off hydrogen supply before introduction of the carbon source for graphene growth. The density of graphene decreased from 72.0 to 2.2 domains/cm2 by turning off hydrogen for 15 min. X-ray photoelectron spectroscopy and Raman spectroscopy studies show that the Cu surface was covered with 3–4 nm thick highly crystalline Cu2O, which would be caused by oxidation by residual oxidative gasses in the chamber during the turning off period. It was also revealed that elevating the temperature in Ar followed by annealing in H2/Ar before turning off hydrogen led to the enlargement of the Cu domain, resulting in the further suppression of nucleation. By optimizing such growth parameters in the CVD process, a single-crystal graphene with ~2.6 mm in diameter was successfully obtained.

  13. Synthesis and modeling of uniform complex metal oxides by close-proximity atmospheric pressure chemical vapor deposition. (United States)

    Hoye, Robert L Z; Muñoz-Rojas, David; Musselman, Kevin P; Vaynzof, Yana; MacManus-Driscoll, Judith L


    A close-proximity atmospheric pressure chemical vapor deposition (AP-CVD) reactor is developed for synthesizing high quality multicomponent metal oxides for electronics. This combines the advantages of a mechanically controllable substrate-manifold spacing and vertical gas flows. As a result, our AP-CVD reactor can rapidly grow uniform crystalline films on a variety of substrate types at low temperatures without requiring plasma enhancements or low pressures. To demonstrate this, we take the zinc magnesium oxide (Zn(1-x)Mg(x)O) system as an example. By introducing the precursor gases vertically and uniformly to the substrate across the gas manifold, we show that films can be produced with only 3% variation in thickness over a 375 mm(2) deposition area. These thicknesses are significantly more uniform than for films from previous AP-CVD reactors. Our films are also compact, pinhole-free, and have a thickness that is linearly controllable by the number of oscillations of the substrate beneath the gas manifold. Using photoluminescence and X-ray diffraction measurements, we show that for Mg contents below 46 at. %, single phase Zn(1-x)Mg(x)O was produced. To further optimize the growth conditions, we developed a model relating the composition of a ternary oxide with the bubbling rates through the metal precursors. We fitted this model to the X-ray photoelectron spectroscopy measured compositions with an error of Δx = 0.0005. This model showed that the incorporation of Mg into ZnO can be maximized by using the maximum bubbling rate through the Mg precursor for each bubbling rate ratio. When applied to poly(3-hexylthiophene-2,5-diyl) hybrid solar cells, our films yielded an open-circuit voltage increase of over 100% by controlling the Mg content. Such films were deposited in short times (under 2 min over 4 cm(2)).


    Directory of Open Access Journals (Sweden)



    Full Text Available The feasibility of deterpenating orange peel oil with supercritical CO2 depends on relevant vapor-liquid equilibrium data because the selectivity of this solvent for limonene and linalool (the two key components of the oil is of crucial importance. The vapor-liquid equilibrium data of the CO2-limonene binary system was measured at 50, 60 and 70oC and pressures up to 10 MPa, and of the CO2-linalool binary system at 50oC and pressures up to 85 bar. These results were compared with published data when available in the literature. The unpublished ternary phase equilibrium of CO2-limonene-linalool was studied at 50oC and up to 9 MPa. Selectivities obtained using these ternary data were compared with those calculated using binary data and indicate that a selective separation of limonene and linalool can be achieved.

  15. Perfluorocarbon emulsion improves oxygen transport of normal and sickle cell human blood in vitro. (United States)

    Torres Filho, Ivo P; Pedro, José Ricardo P; Narayanan, Srinivasan V; Nguyen, Nguyen M; Roseff, Susan D; Spiess, Bruce D


    Perfluorocarbons (PFC) are compounds with high gas solubility that could help deliver O2 to tissues and have been suggested as adjunct therapy to ischemia. Using a newly designed in vitro system, we tested the hypothesis that a third generation PFC emulsion (Oxycyte) increased O2 transport of blood by measuring changes in O2 extraction ratio. The system included a computer-controlled pump and blood-gas exchange chambers to oxygenate and deoxygenate the blood from nine sickle cell disease (SCD) patients and five healthy donors. The flowing blood reached various levels of hemoglobin O2 saturation and O2 partial pressures (PO2), measured using a CO-oximeter and a blood gas analyzer. The mixtures were kept at physiological blood pressure and temperature, constant flow, normobaric conditions, and FiO2 = 0.30. After adding PFC, the measurements suggested an increase in the transport of O2 and CO. Addition of PFC resulted in larger PO2 difference from 15 ± 2 mmHg to 23 ± 2 mmHg. Using normal blood and blood from SCD patients, the average O2 extraction ratio (O2ER) after PFC was significantly higher than baseline. Addition of saline did not cause statistically significant changes. The data suggest increased (facilitated) O2 transport by this PFC emulsion in both normal and SCD blood. © 2013 Wiley Periodicals, Inc.

  16. Investigation of Boron Thermal Diffusion from Atmospheric Pressure Chemical Vapor Deposited Boron Silicate Glass for N-Type Solar Cell Process Application


    Ikuo Kurachi; Kentaro Yoshioka


    An atmospheric pressure chemical vapor deposition (AP-CVD) system has been newly developed for boron silicate glass (BSG) film deposition dedicating to solar cell manufacturing. Using the system, thermal boron diffusion from the BSG film is investigated and confirmed in terms of process stability for surface property before BSG deposition and BSG thickness. No degradation in carrier lifetime is also confirmed. A boron diffusion simulator has been newly developed and demonstrated for optimizat...

  17. Phase-shift, stimuli-responsive perfluorocarbon nanodroplets for drug delivery to cancer. (United States)

    Rapoport, Natalya


    This review focuses on phase-shift perfluorocarbon nanoemulsions whose action depends on an ultrasound-triggered phase shift from a liquid to gas state. For drug-loaded perfluorocarbon nanoemulsions, microbubbles are formed under the action of tumor-directed ultrasound and drug is released locally into tumor volume in this process. This review covers in detail mechanisms involved in the droplet-to-bubble transition as well as mechanisms of ultrasound-mediated drug delivery. Copyright © 2012 Wiley Periodicals, Inc.

  18. Control of the nucleation and quality of graphene grown by low-pressure chemical vapor deposition with acetylene

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Meng, E-mail: [Department of Nanomechanics, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Sasaki, Shinichirou [Department of Nanomechanics, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Suzuki, Ken; Miura, Hideo [Fracture and Reliability Research Institute, Tohoku University, Sendai 980-8579 (Japan)


    Graphical abstract: - Highlights: • For the first time, we succeeded in the LPCVD growth of monolayer graphene using acetylene as the precursor gas. • The growth rate is very high when acetylene is used as the source gas. Our process has exhibited the potential to shorten the growth time of CVD graphene. • We found that the domain size, defects density, layer number and the sheet resistance of graphene can be changed by changing the acetylene flow rates. • We found that it is also possible to form bilayer graphene using acetylene. However, further study are necessary to reduce the defects density. - Abstract: Although many studies have reported the chemical vapor deposition (CVD) growth of large-area monolayer graphene from methane, synthesis of graphene using acetylene as the source gas has not been fully explored. In this study, the low-pressure CVD (LPCVD) growth of graphene from acetylene was systematically investigated. We succeeded in regulating the domain size, defects density, layer number and the sheet resistance of graphene by changing the acetylene flow rates. Scanning electron microscopy and Raman spectroscopy were employed to confirm the layer number, uniformity and quality of the graphene films. It is found that a low flow rate of acetylene (0.28 sccm) is required to form high-quality monolayer graphene in our system. On the other hand, the high acetylene flow rate (7 sccm) will induce the growth of the bilayer graphene domains with high defects density. On the basis of selected area electron diffraction (SAED) pattern, the as-grown monolayer graphene domains were analyzed to be polycrystal. We also discussed the relation between the sheet resistacne and defects density in graphene. Our results provide great insights into the understanding of the CVD growth of monolayer and bilayer graphene from acetylene.

  19. Effects of air temperature and water vapor pressure deficit on storage of the predatory mite Neoseiulus californicus (Acari: Phytoseiidae). (United States)

    Ghazy, Noureldin Abuelfadl; Suzuki, Takeshi; Amano, Hiroshi; Ohyama, Katsumi


    To determine the optimum air temperature and water vapor pressure deficit (VPD) for the storage of the predatory mite, Neoseiulus californicus, 3-day-old mated females were stored at air temperatures of 0, 5, 10, or 15 °C and VPDs of 0.1, 0.3, or 0.5 kPa for 10, 20, or 30 days. At 10 °C and 0.1 kPa, 83 % of females survived after 30 days of storage; this percentage was the highest among all conditions. VPDs of 0.3 and 0.5 kPa regardless of air temperature, and an air temperature of 0 °C regardless of VPD were detrimental to the survival of the females during storage. Since the highest survival was observed at 10 °C and 0.1 kPa, the effect of the storage duration on the post-storage quality of the stored females and their progeny was investigated at 25 °C to evaluate the effectiveness of the storage condition. The oviposition ability of the stored females, hatchability, and sex ratio of their progeny were not affected even when the storage duration was extended to 30 days. Although a slight decrease in the survival during the immature stages of progeny was observed when the storage duration was ≥20 days, the population growth of N. californicus may not be affected when individuals stored in these conditions are applied to greenhouses and agricultural fields. The results indicate that mated N. californicus females can be stored at 10 °C and 0.1 kPa VPD for at least 30 days.

  20. Using an Atmospheric Pressure Chemical Vapor Deposition Process for the Development of V2O5 as an Electrochromic Material

    Directory of Open Access Journals (Sweden)

    Dimitra Vernardou


    Full Text Available Vanadium pentoxide coatings were grown by atmospheric pressure chemical vapor deposition varying the gas precursor ratio (vanadium (IV chloride:water and the substrate temperature. All samples were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, cyclic voltammetry, and transmittance measurements. The water flow rate was found to affect the crystallinity and the morphological characteristics of vanadium pentoxide. Dense stacks of long grains of crystalline oxide are formed at the highest amount of water utilized for a substrate temperature of 450 °C. Accordingly, it was indicated that for higher temperatures and a constant gas precursor ratio of 1:7, the surface morphology becomes flattened, and columnar grains of uniform size and shape are indicated, keeping the high crystalline quality of the material. Hence, it was possible to define a frame of operating parameters wherein single-phase vanadium pentoxide may be reliably expected, including a gas precursor ratio of 1:7 with a substrate temperature of >450 °C. The as-grown vanadium pentoxide at 550 °C for a gas precursor ratio of 1:7 presented the best electrochemical performance, including a diffusion coefficient of 9.19 × 10−11 cm2·s−1, a charge density of 3.1 mC·cm−2, and a coloration efficiency of 336 cm2·C−1. One may then say that this route can be important for the growth of large-scale electrodes with good performance for electrochromic devices.

  1. Spatial and temporal changes in vapor pressure deficit and their impacts on crop yields in China during 1980-2008 (United States)

    Zhang, Shuai; Tao, Fulu; Zhang, Zhao


    Vapor pressure deficit (VPD) is a widely used measure of atmospheric water demand. It is closely related to crop evapotranspiration and consequently has major impacts on crop growth and yields. Most previous studies have focused on the impacts of temperature, precipitation, and solar radiation on crop yields, but the impact of VPD is poorly understood. Here, we investigated the spatial and temporal changes in VPD and their impacts on yields of major crops in China from 1980 to 2008. The results showed that VPD during the growing period of rice, maize, and soybean increased by more than 0.10 kPa (10 yr)-1 in northeastern and southeastern China, although it increased the least during the wheat growing period. Increases in VPD had different impacts on yields for different crops and in different regions. Crop yields generally decreased due to increased VPD, except for wheat in southeastern China. Maize yield was sensitive to VPD in more counties than other crops. Soybean was the most sensitive and rice was the least sensitive to VPD among the major crops. In the past three decades, due to the rising trend in VPD, wheat, maize, and soybean yields declined by more than 10.0% in parts of northeastern China and the North China Plain, while rice yields were little affected. For China as a whole, the trend in VPD during 1980-2008 increased rice yields by 1.32%, but reduced wheat, maize, and soybean yields by 6.02%, 3.19%, and 7.07%, respectively. Maize and soybean in the arid and semi-arid regions in northern China were more sensitive to the increase in VPD. These findings highlight that climate change can affect crop growth and yield through increasing VPD, and water-saving technologies and agronomic management need to be strongly encouraged to adapt to ongoing climate change.

  2. Note: implementation of a cold spot setup for controlled variation of vapor pressures and its application to an InBr containing discharge lamp. (United States)

    Briefi, S


    In order to allow for a systematic investigation of the plasma properties of discharges containing indium halides, which are proposed as an efficient alternative for mercury based low pressure discharge lamps, a controlled variation of the indium halide density is mandatory. This can be achieved by applying a newly designed setup in which a well-defined cold spot location is implemented and the cold spot temperature can be adjusted between 50 and 350 °C without influencing the gas temperature. The performance of the setup has been proved by comparing the calculated evaporated InBr density (using the vapor pressure curve) with the one measured via white light absorption spectroscopy.

  3. Cargo and Carrier Effects of Rapamycin-Loaded Perfluorocarbon Nanoparticles (United States)

    Bibee, Kristin Page

    Nanoparticle-based drug delivery has been championed as a means to increase local delivery of therapeutics while decreasing systemic drug exposure. By targeting the particles, and therefore the drugs, to diseased cells of interest, healthy cells will be spared and side effects avoided. This delivery mechanism would be particularly useful for drugs that interfere with cell growth and proliferation pathways, as blocking proliferation in normal cells leads to significant patient morbidity. Rapamycin is a macrolide and a known inhibitor of mTORC1, a protein complex that plays a crucial role in protein translation and cell growth. This work demonstrates the effects of rapamycin complexed with a nanoparticle carrier on two distinct pathologies: a new triple negative breast cancer cell line and a conventional mouse model of muscular dystrophy (mdx). Rapamycin is able to alter mitochondrial function and thus metabolism in both free and nanoparticle-delivered form without killing the cells. Although nanoparticles are considered to be a benign carrier, this work shows that perfluorocarbon nanoparticles are able to induce autophagy in vitro. The benefits of autophagy induction in cancer cells is cell and stage specific, but has been reported to be useful for radiosensitization of triple negative breast cancers. Additionally, the particles are shown to induce autophagy in the mdx model of Duchenne Muscular Dystrophy and, when loaded with rapamycin, dramatically improve strength even in older animals with muscular dystrophy. Overall, this work enhances our understanding of the cellular effects of perfluorocarbon nanoparticles in two different disease models and enhances prospects for clinical translation of nanoparticle-based drug delivery.

  4. Aerosolized perfluorocarbon improves gas exchange and pulmonary mechanics in preterm lambs with severe respiratory distress syndrome. (United States)

    Murgia, Xabier; Mielgo, Victoria; Valls-i-Soler, Adolf; Ruiz-del-Yerro, Estibaliz; Rey-Santano, Carmen


    Aerosolized perfluorocarbon (PFC) has been proposed as an alternative method of PFC administration; however, the efficacy of aerosolized PFC in a preterm animal model has not yet been demonstrated. Twelve preterm lambs were randomized to two groups: a perfluorodecalin (PFD) aerosol group (n = 6) receiving 10 ml/kg/h of PFD delivered by an intratracheal inhalation catheter followed by 4 h of mechanical ventilation (MV) or the control group, in which animals (n = 6) were managed for 6 h with MV. Gas exchange, pulmonary mechanics, cardiovascular parameters, and cerebral blood flow (CBF) were measured. Both groups developed hypoxia, hypercarbia, and acidosis at baseline. Aerosolized PFD improved oxygenation (P mechanics (P < 0.0001) and changed carbon dioxide values to normal physiological levels, unlike the treatment given to the controls (P < 0.0003). The time course of mean arterial blood pressure and CBF were significantly affected by PFD aerosolization, especially during the first hour of life. CBF gradually decreased during the first hour in the PFD aerosol group and remained stable until the end of the follow-up, whereas CBF remained higher in the control group (P < 0.0028). Aerosolized PFD improves pulmonary function in preterm lambs and should be further investigated as an alternative mode of PFC administration.

  5. Growth CO2 concentration modifies the transpiration response of Populus deltoides to drought and vapor pressure deficit. (United States)

    Engel, Victor C; Griffin, Kevin L; Murthy, Ramesh; Patterson, Lane; Klimas, Christie; Potosnak, Mark


    Cottonwood (Populus deltoides Bartr. ex Marsh.) trees grown for 9 months in elevated carbon dioxide concentration ([CO2]) showed significant increases in height, leaf area and basal diameter relative to trees in a near-ambient [CO2] control treatment. Sample trees in the CO2 treatments were subjected to high and low atmospheric vapor pressure deficits (VPD) over a 5-week period at both high and low soil water contents (SWC). During these periods, transpiration rates at both the leaf and canopy levels were calculated based on sap flow measurements and leaf-to-sapwood area ratios. Leaf-level transpiration rates were approximately equivalent across [CO2] treatments when soil water was not limiting. In contrast, during drought stress, canopy-level transpiration rates were approximately equivalent across [CO2] treatments, indicating that leaf-level fluxes during drought stress were reduced in elevated [CO2] by a factor equal to the leaf area ratio of the two canopies. The shift from equivalent leaf-level transpiration to equivalent canopy-level transpiration with increasing drought stress suggests maximum water use rates were controlled primarily by atmospheric demand at high SWC and by soil water availability at low SWC. Changes in VPD had less effect on transpiration than changes in SWC for trees in both CO2 treatments. Transpiration rates of trees in both CO2 treatments reached maximum values at a VPD of about 2.0 kPa at high SWC, but leveled off and decreased slightly in both canopies as VPD increased above this value. At low SWC, increasing VPD from approximately 1.4 to 2.5 kPa caused transpiration rates to decline slightly in the canopies of trees in both treatments, with significant (P = 0.004) decreases occurring in trees in the near-ambient [CO2] treatment. The transpiration responses at high VPD in the presence of high SWC and throughout the low SWC treatment suggest some hydraulic limitations to water use occurred. Comparisons of midday leaf water potentials

  6. Water vapor pressure over molten KH2PO4 and demonstration of water electrolysis at ∼300ºC

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Nikiforov, Aleksey Valerievich; Petrushina, Irina


    with platinum electrodes and the electrolyte melt). The formation of mixtures of hydrogen and oxygen gases as well as the water vapor was detected by Raman spectroscopy. In this way it was demonstrated that water is present in the new electrolyte: molten KH2PO4 can be split by electrolysis via the reaction 2H2O......—H2O. The water vapor pressure above the melt, when contained in a closed ampoule, was determined quantitatively vs. temperature by use of Raman spectroscopy with methane or hydrogen gas as an internal calibration standard, using newly established relative ratios of Raman scattering cross sections...... of hydrogen-bonding has a high affinity for remaining in the melt. The formed hydrogen and oxygen gasses were detected by means of the characteristic Raman gas-phase spectra....

  7. Unified Application of Vapor Screen Flow Visualization and Pressure Sensitive Paint Measurement Techniques to Vortex- and Shock Wave-Dominated Flow Fields (United States)

    Erickson, Gary E.


    Laser vapor screen (LVS) flow visualization and pressure sensitive paint (PSP) techniques were applied in a unified approach to wind tunnel testing of slender wing and missile configurations dominated by vortex flows and shock waves at subsonic, transonic, and supersonic speeds. The off-surface cross-flow patterns using the LVS technique were combined with global PSP surface static pressure mappings to characterize the leading-edge vortices and shock waves that coexist and interact at high angles of attack. The synthesis of LVS and PSP techniques was also effective in identifying the significant effects of passive surface porosity and the presence of vertical tail surfaces on the flow topologies. An overview is given of LVS and PSP applications in selected experiments on small-scale models of generic slender wing and missile configurations in the NASA Langley Research Center (NASA LaRC) Unitary Plan Wind Tunnel (UPWT) and 8-Foot Transonic Pressure Tunnel (8-Foot TPT).

  8. Unified Application Vapor Screen Flow Visualization and Pressure Sensitive Paint Measurement Techniques to Vortex- and Shock Wave-Dominated Flow Fields (United States)

    Erickson, Gary E.


    Laser vapor screen (LVS) flow visualization and pressure sensitive paint (PSP) techniques were applied in a unified approach to wind tunnel testing of slender wing and missile configurations dominated by vortex flows and shock waves at subsonic, transonic, and supersonic speeds. The off-surface cross-flow patterns using the LVS technique were combined with global PSP surface static pressure mappings to characterize the leading-edge vortices and shock waves that coexist and interact at high angles of attack (alpha). The synthesis of LVS and PSP techniques was also effective in identifying the significant effects of passive surface porosity and the presence of vertical tail surfaces on the flow topologies. An overview is given of LVS and PSP applications in selected experiments on small-scale models of generic slender wing and missile configurations in the NASA Langley Research Center (NASA LaRC) Unitary Plan Wind Tunnel (UPWT) and 8-Foot Transonic Pressure Tunnel (8-Foot TPT).

  9. The influence of methanol addition during the film growth of SnO 2 by atmospheric pressure chemical vapor deposition

    NARCIS (Netherlands)

    Volintiru, I.; Graaf, A. de; Deelen, J. van; Poodt, P.W.G.


    Undoped tin oxide (SnO2) thin films have been deposited in a stagnant point flow chemical vapor deposition reactor from a water/tin tetrachloride mixture. By adding methanol during the deposition process the film electrical properties change significantly: ten times more conductive SnO 2 films are

  10. Low temperature carrier transport study of monolayer MoS{sub 2} field effect transistors prepared by chemical vapor deposition under an atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xinke, E-mail:, E-mail:; He, Jiazhu; Tang, Dan; Lu, Youming; Zhu, Deliang; Liu, Wenjun; Cao, Peijiang; Han, Sun [College of Materials Science and Engineering, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Nanshan District Key Lab for Biopolymer and Safety Evaluation, Shenzhen University, 3688 Nanhai Ave, Shenzhen 518060 (China); Liu, Qiang; Wen, Jiao; Yu, Wenjie [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, CAS, 865 Chang Ning Road, Shanghai 200050 (China); Liu, Wenjun [State Key Laboratory of ASIC and System, Department of Microelectronics, Fudan University, 220 Handan Road, Shanghai 200433 (China); Wu, Jing, E-mail:, E-mail: [Department of Physics, National University of Singapore, 21 Lower Kent Ridge Road, 117576 Singapore (Singapore); He, Zhubing [Department of Materials Science and Engineering, South University of Science and Technology of China, 1088 Xueyuan Road, Shenzhen 518055 (China); Ang, Kah-Wee [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, 117583 Singapore (Singapore)


    Large size monolayer Molybdenum disulphide (MoS{sub 2}) was successfully grown by chemical vapor deposition method under an atmospheric pressure. The electrical transport properties of the fabricated back-gate monolayer MoS{sub 2} field effect transistors (FETs) were investigated under low temperatures; a peak field effect mobility of 59 cm{sup 2}V{sup −1}s{sup −1} was achieved. With the assist of Raman measurement under low temperature, this work identified the mobility limiting factor for the monolayer MoS{sub 2} FETs: homopolar phonon scattering under low temperature and electron-polar optical phonon scattering at room temperature.

  11. Molar Heat Capacity (Cv) for Saturated and Compressed Liquid and Vapor Nitrogen from 65 to 300 K at Pressures to 35 MPa. (United States)

    Magee, J W


    Molar heat capacities at constant volume (Cv ,) for nitrogen have been measured with an automated adiabatic calorimeter. The temperatures ranged from 65 to 300 K, while pressures were as high as 35 MPa. Calorimetric data were obtained for a total of 276 state conditions on 14 isochores. Extensive results which were obtained in the saturated liquid region (Cv((2)) and Cσ ) demonstrate the internal consistency of the Cv (ρ,T) data and also show satisfactory agreement with published heat capacity data. The overall uncertainty of the Cv values ranges from 2% in the vapor to 0.5% in the liquid.

  12. Interstitial Boron-Doped TiO2 Thin Films: The Significant Effect of Boron on TiO2 Coatings Grown by Atmospheric Pressure Chemical Vapor Deposition. (United States)

    Quesada-González, Miguel; Boscher, Nicolas D; Carmalt, Claire J; Parkin, Ivan P


    The work presented here describes the preparation of transparent interstitial boron-doped TiO2 thin-films by atmospheric pressure chemical vapor deposition (APCVD). The interstitial boron-doping, on TiO2, proved by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), is shown to enhance the crystallinity and significantly improve the photocatalytic activity of the TiO2 films. The synthesis, highly suitable for a reel-to-reel process, has been carried out in one step.

  13. Microspectroscopic imaging of solution plasma: How do its physical properties and chemical species evolve in atmospheric-pressure water vapor bubbles? (United States)

    Yui, Hiroharu; Banno, Motohiro


    In this article, we review the development of scientific instruments for obtaining information on the evolution of physical properties and chemical species of solution plasma (SP). When a pulsed high voltage is applied between electrodes immersed in an aqueous solution, SP is formed in water vapor bubbles transiently generated in the solution under atmospheric pressure. To clarify how SP emerges in water vapor bubbles and is sustained in solutions, an instrument with micrometer spatial resolution and nanosecond temporal resolution is required. To meet these requirements, a microscopic system with a custom-made optical discharge cell was newly developed, where the working distance between the SP and the microscopic objective lens was minimized. A hollow electrode equipped in the discharge cell also enabled us to control the chemical composition in water vapor bubbles. To study the spatial and temporal evolutions of chemical species in micrometer and nano- to microsecond regions, a streak camera with a spectrometer and a CCD detector with a time-gated electronic device were combined with the microscope system. The developed instrument is expected to contribute to providing a new means of developing new schemes for chemical reactions and material syntheses.

  14. Biomedical photoacoustics beyond thermal expansion using triggered nanodroplet vaporization for contrast-enhanced imaging. (United States)

    Wilson, Katheryne; Homan, Kimberly; Emelianov, Stanislav


    Since being discovered by Alexander Bell, photoacoustics may again be seeing major resurgence in biomedical imaging. Photoacoustics is a non-ionizing, functional imaging modality capable of high contrast images of optical absorption at depths significantly greater than traditional optical imaging techniques. Optical contrast agents have been used to extend photoacoustics to molecular imaging. Here we introduce an exogenous contrast agent that utilizes vaporization for photoacoustic signal generation, providing significantly higher signal amplitude than that from the traditionally used mechanism, thermal expansion. Our agent consists of liquid perfluorocarbon nanodroplets with encapsulated plasmonic nanoparticles, entitled photoacoustic nanodroplets. Upon pulsed laser irradiation, liquid perfluorocarbon undergoes a liquid-to-gas phase transition generating giant photoacoustic transients from these dwarf nanoparticles. Once triggered, the gaseous phase provides ultrasound contrast enhancement. We demonstrate in phantom and animal studies that photoacoustic nanodroplets act as dual-contrast agents for both photoacoustic and ultrasound imaging through optically triggered vaporization.

  15. [Red cell substitutes: perfluorocarbon emulsions and hemoglobin solutions]. (United States)

    Rémy, B; Deby-Dupont, G; D'Ans, V; Ernest, P; Lamy, M


    To review the current data on perfluorocarbon (PFC) emulsions and haemoglobin (Hb) solutions. For this paper we analysed the literature using Medline search along with major review articles. The collected articles were reviewed and selected according to their quality and originality. PFCs are synthetic fluorinated hydrocarbons capable of dissolving, at increased FIO2, large amounts of oxygen. They deliver oxygen at tissular level, and are administered as emulsions containing particles of around 0.1 micron, reaching the smallest vessels. They are exhaled unchanged by the lungs within 7 days. The first clinically used PFC was Fluosol-DA 20%. Currently, Oxyfluor 40% and Oxygent 60% are under evaluation. PFCs are not true blood substitutes, but rather a means to support tissue oxygenation during extreme haemodilution. Solutions of free Hb do not require compatibility testing and are fully saturated with oxygen at ambient FIO2. Hb is either human, bovine or recombinant Hb. In order to maintain adequate intravascular half-life and affinity for oxygen, the Hb molecules are modified by internal cross-linking, polymerisation and encapsulation. After promising results using animal models, some of these modified Hb solutions are now undergoing phase III clinical trials. Among these, diaspirin cross-linked haemoglobin (DCLHb) has been tested in cardiac and orthopaedic surgery, as well as in trauma patients. The initial results of these multicentre trials are currently being analysed.

  16. Chemical and radiolytical characterization of some perfluorocarbon fluids used as coolants for LHC experiments

    CERN Document Server

    Battistin, M; Setnescu, R; Teissandier, B; CERN. Geneva. TS Department


    Perfluorocarbon fluids, - mainly C6F14 - used as coolants within High Energy Physics Detectors in the Large Hadrons Collider (LHC) at CERN, were characterized by applying mainly the following methods: GC, FT-IR and UV-Vis. The aim of this work was the quality control, the identification and the quantification of different impurities which could increase the radiation sensitivity of these fluids. Thus, the presence of H containing molecules within perfluorocarbons strongly influences the appearance of hydrofluoric acid during their irradiation. The procedures settled-up in this work are sensitive to the presence of such impurities and would be used for the analyses of the received perfluorocarbon fluids as well as to assess the radiation induced modifications and the efficiency of their purification treatments.

  17. Density distributions of OH, Na, water vapor, and water mist in atmospheric-pressure dc helium glow plasmas in contact with NaCl solution (United States)

    Sasaki, Koichi; Ishigame, Hiroaki; Nishiyama, Shusuke


    This paper reports the density distributions of OH, Na, water vapor and water mist in atmospheric-pressure dc helium glow plasmas in contact with NaCl solution. The densities of OH, Na and H2O had different spatial distributions, while the Na density had a similar distribution to mist, suggesting that mist is the source of Na in the gas phase. When the flow rate of helium toward the electrolyte surface was increased, the distributions of all the species densities concentrated in the neighboring region to the electrolyte surface more significantly. The densities of all the species were sensitive to the electric polarity of the power supply. In particular, we never detected Na and mist when the electrolyte worked as the anode of the dc discharge. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  18. Effect of pressure and Al doping on structural and optical properties of ZnO nanowires synthesized by chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Mohanta, Antaryami [Oak Ridge Institute for Science and Education, Research Participation Program, U.S. Army Aviation and Missile Research Development and Engineering Center (AMRDEC), Redstone Arsenal, AL 35898 (United States); Simmons, Jay G. [Department of Chemistry, Duke University, Durham, NC 27708 (United States); Everitt, Henry O. [U.S. Army Aviation and Missile Research Development and Engineering Center (AMRDEC), Redstone Arsenal, AL 35898 (United States); Shen, Gang; Margaret Kim, Seongsin [Department of Electrical and Computer Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States); Kung, Patrick, E-mail: [Department of Electrical and Computer Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States)


    The effect of Al doping concentration and oxygen ambient pressure on the structural and optical properties of chemical vapor deposition-grown, Al-doped ZnO nanowires is studied. As Al doping increases, the strength of the broad visible emission band decreases and the UV emission increases, but the growth rate depends on the oxygen pressure in a complex manner. Together, these behaviors suggest that Al doping is effective in reducing the number of oxygen vacancies responsible for visible emission, especially at low oxygen ambient pressure. The intensities and quantum efficiencies of these emission mechanisms are discussed in terms of the effect growth and doping conditions have on the underlying excitonic decay mechanisms. -- Highlights: • Correlated study of the photoluminescence of undoped and Al-doped ZnO nanowires. • Comparative study of structural and optical properties of ZnO and Al:ZnO nanowires. • Study of excitonic decay relaxation channels as function of pressure and Al doping. • More effective reduction of oxygen vacancies by Al doping at lower pressure.

  19. Thermoeconomic analysis of an integrated multi-effect desalination thermal vapor compression (MED-TVC) system with a trigeneration system using triple-pressure HRSG (United States)

    Ghaebi, Hadi; Abbaspour, Ghader


    In this research, thermoeconomic analysis of a multi-effect desalination thermal vapor compression (MED-TVC) system integrated with a trigeneration system with a gas turbine prime mover is carried out. The integrated system comprises of a compressor, a combustion chamber, a gas turbine, a triple-pressure (low, medium and high pressures) heat recovery steam generator (HRSG) system, an absorption chiller cycle (ACC), and a multi-effect desalination (MED) system. Low pressure steam produced in the HRSG is used to drive absorption chiller cycle, medium pressure is used in desalination system and high pressure superheated steam is used for heating purposes. For thermodynamic and thermoeconomic analysis of the proposed integrated system, Engineering Equation Solver (EES) is used by employing mass, energy, exergy, and cost balance equations for each component of system. The results of the modeling showed that with the new design, the exergy efficiency in the base design will increase to 57.5%. In addition, thermoeconomic analysis revealed that the net power, heating, fresh water and cooling have the highest production cost, respectively.


    Vapor pressures, compressibilities, expansivities, and molar volumes of the liquid phase have been measured between room temperature and the critical temperature for a series of fluorinated ethers: CF3OCF2OCF3, CF3OCF2CF2H, c-CF2CF2CF2O, CF3OCF2H, and CF3OCH3. Vapor-phase non-ide...

  1. Perfluorocarbon emulsions and cardiopulmonary bypass: a technique for the future. (United States)

    Spiess, B D; Cochran, R P


    Artificial blood has been sought for a considerable period of time and two major lines of research have led to FDA testing of some possible compounds. The two major types of compounds are polymerized hemoglobin moieties and perfluorocarbon emulsions (PFC). Polymerized hemoglobin preparations have the ability to carry oxygen and release it in a manner similar to the oxyhemoglobin dissociation curve of whole blood. PFCs carry oxygen, nitrogen and carbon dioxide, as well as all other non-polar gases, by enhanced chemical solubility. Therefore, all dissolved gases are available for metabolic utilization and no sinusoidal release curve of oxygen is encountered. Early PFC emulsions had problems with toxicity of the emulsifier and were difficult to get into their emulsion for infusion. Furthermore they were very dilute in the active ingredient for gas transport. Today there are second generation PFCs becoming available that have a 40% concentration of the PFC and therefore the potential for gas transport is greatly increased. The PFC emulsions have a very small size, 0.1 microns, so the surface for gas exchange is massively increased as well as the potential increased for perfusion into areas of potentially sludged erythrocytes. Work with the PFCs has shown them now to be able to carry adequate oxygen to work as blood substitutes. They have shown protection from air embolism in a number of animal and end-organ models. What makes the PFCs unique is their ability to carry/absorb nitrogen and therefore protect from gas embolization. There are data in animal models showing significant cerebral protection in cardiopulmonary bypass models. The new PFCs should sometime in the not-too-distant future be tested in human bypass with assessments of neuropsychiatric dysfunction and stroke.

  2. Delaying blood transfusion in experimental acute anemia with a perfluorocarbon emulsion. (United States)

    Cabrales, Pedro; Carlos Briceño, Juan


    To avoid unnecessary blood transfusions, physiologic transfusion triggers, rather than exclusively hemoglobin-based transfusion triggers, have been suggested. The objective of this study was to determine systemic and microvascular effects of using a perfluorocarbon-based oxygen carrier (PFCOC) to maintain perfusion and oxygenation during extreme anemia. The hamster (weight, 55-65 g) window chamber model was used. Two isovolemic hemodilution steps were performed using hydroxyethyl starch, 10%, at normoxic conditions to a hematocrit of 19% (hemoglobin, 5.5 g/dl), the point at which the transfusion trigger was reached. Two additional hemodilution exchanges using the PFCOC (Oxycyte) and increasing the fraction of inspired oxygen to 1.0 were performed to reduce the hematocrit to 11% (hemoglobin, 3.8 g/dl) and 6% (hemoglobin, 2.0 g/dl), respectively. No control group was used in the study because this concentration of hemodilution is lethal with conventional plasma expanders. Systemic parameters, microvascular perfusion, functional capillary density, and oxygen tensions across the microvascular network were measured. At 6% hematocrit, the PFCOC maintained mean arterial pressure, cardiac output, systemic oxygen delivery, and oxygen consumption. As hematocrit was decreased from 11% to 6%, functional capillary density, calculated microvascular oxygen delivery, and oxygen consumption decreased; and the oxygen extraction ratio was close to 100%. Peripheral tissue oxygenation was not predicted by systemic oxygenation. The PFCOC, in conjunction with hyperoxia, was able to sustain organ function and partially provide systemic oxygenation during extreme anemia during the observation period. The PFCOC can work as a bridge until erythrocytes are available for transfusion or when additional oxygen is required, despite the possible limitations in peripheral tissue oxygenation.

  3. The electrical properties of low pressure chemical vapor deposition Ga doped ZnO thin films depending on chemical bonding configuration (United States)

    Jung, Hanearl; Kim, Doyoung; Kim, Hyungjun


    The electrical and chemical properties of low pressure chemical vapor deposition (LP-CVD) Ga doped ZnO (ZnO:Ga) films were systematically investigated using Hall measurement and X-ray photoemission spectroscopy (XPS). Diethylzinc (DEZ) and O2 gas were used as precursor and reactant gas, respectively, and trimethyl gallium (TMGa) was used as a Ga doping source. Initially, the electrical properties of undoped LP-CVD ZnO films depending on the partial pressure of DEZ and O2 ratio were investigated using X-ray diffraction (XRD) by changing partial pressure of DEZ from 40 to 140 mTorr and that of O2 from 40 to 80 mTorr. The resistivity was reduced by Ga doping from 7.24 × 10-3 Ω cm for undoped ZnO to 2.05 × 10-3 Ω cm for Ga doped ZnO at the TMG pressure of 8 mTorr. The change of electric properties of Ga doped ZnO with varying the amount of Ga dopants was systematically discussed based on the structural crystallinity and chemical bonding configuration, analyzed by XRD and XPS, respectively.

  4. The electrical properties of low pressure chemical vapor deposition Ga doped ZnO thin films depending on chemical bonding configuration

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hanearl [School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Kim, Doyoung [School of Electrical and Electronic Engineering, Ulsan College, 57 Daehak-ro, Nam-gu, Ulsan 680-749 (Korea, Republic of); Kim, Hyungjun, E-mail: [School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of)


    Highlights: • Undoped and Ga doped ZnO thin films were deposited using DEZ and TMGa. • Effects of Ga doping using TMGa in Ga doped ZnO were investigated. • Degraded properties from excessive doping were analyzed using chemical bondings. - Abstract: The electrical and chemical properties of low pressure chemical vapor deposition (LP-CVD) Ga doped ZnO (ZnO:Ga) films were systematically investigated using Hall measurement and X-ray photoemission spectroscopy (XPS). Diethylzinc (DEZ) and O{sub 2} gas were used as precursor and reactant gas, respectively, and trimethyl gallium (TMGa) was used as a Ga doping source. Initially, the electrical properties of undoped LP-CVD ZnO films depending on the partial pressure of DEZ and O{sub 2} ratio were investigated using X-ray diffraction (XRD) by changing partial pressure of DEZ from 40 to 140 mTorr and that of O{sub 2} from 40 to 80 mTorr. The resistivity was reduced by Ga doping from 7.24 × 10{sup −3} Ω cm for undoped ZnO to 2.05 × 10{sup −3} Ω cm for Ga doped ZnO at the TMG pressure of 8 mTorr. The change of electric properties of Ga doped ZnO with varying the amount of Ga dopants was systematically discussed based on the structural crystallinity and chemical bonding configuration, analyzed by XRD and XPS, respectively.

  5. Prediciton of high-pressure vapor liquid equilibrium of six binary systems, carbon dioxide with six esters, using an artificial neural network model

    Directory of Open Access Journals (Sweden)

    C. Si-Moussa


    Full Text Available Artificial neural networks are applied to high-pressure vapor liquid equilibrium (VLE related literature data to develop and validate a model capable of predicting VLE of six CO2-ester binaries (CO2-ethyl caprate, CO2-ethyl caproate, CO2-ethyl caprylate, CO2-diethyl carbonate, CO2-ethyl butyrate and CO2-isopropyl acetate. A feed forward, back propagation network is used with one hidden layer. The model has five inputs (two intensive state variables and three pure ester properties and two outputs (two intensive state variables.The network is systematically trained with 112 data points in the temperature and pressure ranges (308.2-328.2 K, (1.665-9.218 MPa respectively and is validated with 56 data points in the temperature range (308.2-328.2 K. Different combinations of network architecture and training algorithms are studied. The training and validation strategy is focused on the use of a validation agreement vector, determined from linear regression analysis of the plots of the predicted versus experimental outputs, as an indication of the predictive ability of the neural network model. Statistical analyses of the predictability of the optimised neural network model show excellent agreement with experimental data (a coefficient of correlation equal to 0.9995 and 0.9886, and a root mean square error equal to 0.0595 and 0.00032 for the predicted equilibrium pressure and CO2 vapor phase composition respectively. Furthermore, the comparison in terms of average absolute relative deviation between the predicted results for each binary for the whole temperature range and literature results predicted by some cubic equation of state with various mixing rules and excess Gibbs energy models shows that the artificial neural network model gives far better results.

  6. Hemodynamic effects of partial liquid ventilation with perfluorocarbon in acute lung injury

    NARCIS (Netherlands)

    R.J.M. Houmes (Robert Jan); S.J.C. Verbrugge (Serge); E. Hendrik (Edwin); B.F. Lachmann (Burkhard)


    textabstractObjective: To assess the effect of partial liquid ventilation with perfluorocarbons on hemodynamics and gas exchange in large pigs with induced acute lung injury (ALI). Design: Randomized, prospective, double-control, experimental study. Setting: Experimental intensive care unit of a

  7. Improving the dielectric properties of an electrowetting-on-dielectric microfluidic device with a low-pressure chemical vapor deposited Si3N4 dielectric layer. (United States)

    Shen, Hsien-Hua; Chung, Lung-Yuan; Yao, Da-Jeng


    Dielectric breakdown is a common problem in a digital microfluidic system, which limits its application in chemical or biomedical applications. We propose a new fabrication of an electrowetting-on-dielectric (EWOD) device using Si3N4 deposited by low-pressure chemical vapor deposition (LPCVD) as a dielectric layer. This material exhibits a greater relative permittivity, purity, uniformity, and biocompatibility than polymeric films. These properties also increase the breakdown voltage of a dielectric layer and increase the stability of an EWOD system when applied in biomedical research. Medium droplets with mouse embryos were manipulated in this manner. The electrical properties of the Si3N4 dielectric layer-breakdown voltage, refractive index, relative permittivity, and variation of contact angle with input voltage-were investigated and compared with a traditional Si3N4 dielectric layer deposited as a plasma-enhanced chemical vapor deposition to confirm the potential of LPCVD Si3N4 applied as the dielectric layer of an EWOD digital microfluidic system.

  8. Improving the dielectric properties of an electrowetting-on-dielectric microfluidic device with a low-pressure chemical vapor deposited Si3N4 dielectric layer (United States)

    Shen, Hsien-Hua; Chung, Lung-Yuan


    Dielectric breakdown is a common problem in a digital microfluidic system, which limits its application in chemical or biomedical applications. We propose a new fabrication of an electrowetting-on-dielectric (EWOD) device using Si3N4 deposited by low-pressure chemical vapor deposition (LPCVD) as a dielectric layer. This material exhibits a greater relative permittivity, purity, uniformity, and biocompatibility than polymeric films. These properties also increase the breakdown voltage of a dielectric layer and increase the stability of an EWOD system when applied in biomedical research. Medium droplets with mouse embryos were manipulated in this manner. The electrical properties of the Si3N4 dielectric layer—breakdown voltage, refractive index, relative permittivity, and variation of contact angle with input voltage—were investigated and compared with a traditional Si3N4 dielectric layer deposited as a plasma-enhanced chemical vapor deposition to confirm the potential of LPCVD Si3N4 applied as the dielectric layer of an EWOD digital microfluidic system. PMID:25825614

  9. Origin of donor and acceptor species in undoped ZnSe grown by low-pressure metalorganic chemical vapor deposition (United States)

    Morimoto, Keizo


    Effects of the [H2 Se]/[Dimethylzinc] source ratio on the electrical properties in the temperature range of 15-300 K and on the cathodoluminescence properties at 77 K have been investigated for undoped ZnSe films grown in one deposition run on (100)GaAs substrates at 350 °C by metalorganic chemical vapor deposition. The properties correlated with each other and depended on the degrees of deviation from stoichiometry. The dominant donor is identified with selenium vacancy from the dependence of donor concentration on the ratio and on the film thickness. Two kinds of acceptors were introduced according to the deviation from stoichiometry. They are tentatively associated with NSe and NaZn . Extended lattice defects which reduce the electron mobility are favored at the high ratios and they seem a principal factor of the high-resistive property of this material.

  10. Mathematical relationships between vapor pressure, water solubility, Henry's law constant, n-octanol/water partition coefficent and gas chromatographic retention index of polychlorinated-dibenzo-dioxins. (United States)

    Wan, Y H; Wong, P K


    Mathematical relationships between vapor pressures (P), water solubilities (S), Henry's law constants (Hc). noctanol/water partition coefficients (Kow) and gas chromatograph retention indices (GC-RIs) of polychlorinated-dibenzo-dioxins (PCDDs) were established. A model equation was established between GC-RIs (= RI) and other physico-chemical parameters (K) of PCDDs in the form of log K = aRI2 + bRI + c with correlation coefficients (R2) greater than 0.97, except Hc. These equations were derived from 56 experimental data of PCDDs reported previously. The values of P, S, Hc and Kow of PCDDs predicted by these equations based on their GC-RIs in the present study deviated from those calculated by the SOFA method in a previous study by only 0.19, 0.13, 0.18 and 0.096 log units, respectively.

  11. Experimental Study on the Mercury Vapor Pressures in Amalgam-Dosed Discharge Tubes for Compact Fluorescent Lamps during Switch-off Period (United States)

    Yasuda, Takeo; Kando, Masashi

    Ballast-integrated compact fluorescent lamps are widely used for replacing incandescent lamps as energy saving alternative light sources. In spite of their high efficacies, the luminous run-up characteristics of the lamps having outer globes are slow and rather unsatisfactory, especially within a second or two. This problem is due to the lower mercury vapor pressure PHg of amalgam dosed in the discharge tube than that of liquid mercury. In order to improve the luminous flux at starting the lamp ignition, the PHg changes in the discharge tubes including bismuth-indium main amalgam and indium auxiliary amalgam were studied during switch-off period by atomic absorption spectrometry using 254 nm line. The amounts of mercury absorbed in both the main and auxiliary amalgam were also measured by wet chemical analyses. It is found that the PHg during switch-off period is not controlled by only the auxiliary amalgam but also the main amalgam.

  12. High-throughput walkthrough detection portal for counter terrorism: detection of triacetone triperoxide (TATP) vapor by atmospheric-pressure chemical ionization ion trap mass spectrometry. (United States)

    Takada, Yasuaki; Nagano, Hisashi; Suzuki, Yasutaka; Sugiyama, Masuyuki; Nakajima, Eri; Hashimoto, Yuichiro; Sakairi, Minoru


    With the aim of improving security, a high-throughput portal system for detecting triacetone triperoxide (TATP) vapor emitted from passengers and luggage was developed. The portal system consists of a push-pull air sampler, an atmospheric-pressure chemical ionization (APCI) ion source, and an explosives detector based on mass spectrometry. To improve the sensitivity of the explosives detector, a novel linear ion trap mass spectrometer with wire electrodes (wire-LIT) is installed in the portal system. TATP signals were clearly obtained 2 s after the subject under detection passed through the portal system. Preliminary results on sensitivity and throughput show that the portal system is a useful tool for preventing the use of TATP-based improvised explosive devices by screening persons in places where many people are coming and going. Copyright © 2011 John Wiley & Sons, Ltd.

  13. Uniform, stable, and efficient planar-heterojunction perovskite solar cells by facile low-pressure chemical vapor deposition under fully open-air conditions. (United States)

    Luo, Paifeng; Liu, Zhaofan; Xia, Wei; Yuan, Chenchen; Cheng, Jigui; Lu, Yingwei


    Recently, hybrid perovskite solar cells (PSCs) have attracted extensive attention due to their high efficiency and simple preparing process. Herein, a facile low-pressure chemical vapor deposition (LPCVD) technology is first developed to fabricate PSCs, which can effectively reduce the over-rapid intercalating reaction rate and easily overcome this blocking issue during the solution process. As a result, the prepared uniform perovskite films exhibit good crystallization, strong absorption, and long carrier diffusion length. More strikingly, CH3NH3PbI3 absorbers by LPCVD demonstrate excellent moisture-resistant feature even under laser illumination and high-temperature conditions, which indicates that our proprietary method is very suitable for the future low-cost, nonvacuum production of the new generation photovoltaic devices. Finally, high efficiency of 12.73% is successfully achieved under fully open-air conditions. To the best of our knowledge, this is the first report of efficient PSCs with such a high humidity above 60%.

  14. Occurrence of cubic GaN and strain relaxation in GaN buffer layers grown by low-pressure metalorganic vapor phase epitaxy on (0001) sapphire substrates (United States)

    Cheng, Lisen; Zhou, Kuan; Zhang, Ze; Zhang, Guoyi; Yang, Zhijian; Tong, Yuzhen


    Investigations on GaN buffer layers grown by low-pressure metalorganic vapor phase epitaxy on (0001) sapphire substrates indicated that the mechanisms by way of which GaN buffer layers relax stresses introduced by the lattice mismatch and thermal expansion coefficient difference between GaN epilayer and sapphire substrate are related to both the crystallographic structure of GaN and thickness of the buffer layers. Beside forming misfit dislocations, mismatch-induced stresses can also be relaxed by forming stacking faults and microtwin boundaries parallel to (11-1) of GaN near the interface between GaN and sapphire substrate in cubic GaN buffer layers. It was found that, in cubic GaN buffer layers, there exists a critical thickness within which the stacking faults and/or microtwin boundaries parallel to (11-1) of GaN can be formed. This critical value is determined to be 50 nm.

  15. Chemical purging of an intermediate steam heater of a boiler unit at supercritical pressure using moist vapor with ammonia salt pressure (EDEK)

    Energy Technology Data Exchange (ETDEWEB)

    Aleynikov, G.I.; Aldayev, V.A.; Kuz' micheva, L.V.; Mamet, A.P.; Taratata, V.A.


    The technology of chemical purging of intermediate steam heater with moist vapor with the addition of reagents, for example ammonia salt EDTK (AEDTK), has been developed. Conditions of conducting chemical purging under test stand conditions have been determined: the concentration of AEDKT, moisture value, temperature of the cleansing agent, rate of its movement and corrosion activity in the presence and in the absence of corrosion inhibitors are determined. Under operating conditions the chemical purging technology using moist steam with the addition of AEDTK and corrosion inhibitors was checked while carrying out cleansing of TGMP-114 steam unit superheaters of a 300MW power unit of the Kostromoskaya state regional power plant. The amount of deposits on the internal surface of the II stage of the superheater following 50,000 hours of use was 2500-3000g/m/sup 2/; the deposits were very dense and consisted of scale.

  16. Effect of Growth Pressure on Epitaxial Graphene Grown on 4H-SiC Substrates by Using Ethene Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Shuxian Cai


    Full Text Available The Si(0001 face and C(000-1 face dependences on growth pressure of epitaxial graphene (EG grown on 4H-SiC substrates by ethene chemical vapor deposition (CVD was studied using atomic force microscopy (AFM and micro-Raman spectroscopy (μ-Raman. AFM revealed that EGs on Si-faced substrates had clear stepped morphologies due to surface step bunching. However, This EG formation did not occur on C-faced substrates. It was shown by μ-Raman that the properties of EG on both polar faces were different. EGs on Si-faced substrates were relatively thinner and more uniform than on C-faced substrates at low growth pressure. On the other hand, D band related defects always appeared in EGs on Si-faced substrates, but they did not appear in EG on C-faced substrate at an appropriate growth pressure. This was due to the μ-Raman covering the step edges when measurements were performed on Si-faced substrates. The results of this study are useful for optimized growth of EG on polar surfaces of SiC substrates.

  17. Pressure drop and heat transfer during two-phase flow vaporization of propane in horizontal smooth minichannels

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kwang-Il; Pamitran, A.S. [Graduate School, Chonnam National University, San 96-1, Dunduk-Dong, Yeosu, Chonnam 550-749 (Korea); Oh, Jong-Taek [Department of Refrigeration and Air Conditioning Engineering, Chonnam National University, San 96-1, Dunduk-dong, Yeosu, Chonnam 550-749 (Korea); Saito, Kiyoshi [Department of Applied Mechanics and Aerospace Engineering, Waseda University, 1-104, Totsuka-machi, Shinjuku-ku, Tokyo 169-8050 (Japan)


    This study examined the two-phase flow boiling pressure drop and heat transfer for propane, as a long term alternative refrigerant, in horizontal minichannels. The pressure drop and local heat transfer coefficients were obtained for heat fluxes ranging from 5-20 kW m{sup -2}, mass fluxes ranging from 50-400 kg m{sup -2} s{sup -1}, saturation temperatures of 10, 5 and 0 C, and quality up to 1.0. The test section was made of stainless steel tubes with inner diameters of 1.5 mm and 3.0 mm, and lengths of 1000 mm and 2000 mm, respectively. The present study showed the effect of mass flux, heat flux, inner tube diameter and saturation temperature on pressure drop and heat transfer coefficient. The experimental results were compared against several existing pressure drop and heat transfer coefficient prediction methods. Because the study on evaporation with propane in minichannels was limited, new correlations of pressure drop and boiling heat transfer coefficient were developed in this present study. (author)

  18. Perfluorocarbons in the global atmosphere: tetrafluoromethane, hexafluoroethane, and octafluoropropane

    Directory of Open Access Journals (Sweden)

    J. Mühle


    Full Text Available We present atmospheric baseline growth rates from the 1970s to the present for the long-lived, strongly infrared-absorbing perfluorocarbons (PFCs tetrafluoromethane (CF4, hexafluoroethane (C2F6, and octafluoropropane (C3F8 in both hemispheres, measured with improved accuracies (~1–2% and precisions (<0.3%, or <0.2 ppt (parts per trillion dry air mole fraction, for CF4; <1.5%, or <0.06 ppt, for C2F6; <4.5%, or <0.02 ppt, for C3F8 within the Advanced Global Atmospheric Gases Experiment (AGAGE. Pre-industrial background values of 34.7±0.2 ppt CF4 and 0.1±0.02 ppt C2F6 were measured in air extracted from Greenland ice and Antarctic firn. Anthropogenic sources are thought to be primary aluminum production (CF4, C2F6, C3F8, semiconductor production (C2F6, CF4, C3F8 and refrigeration use (C3F8. Global emissions calculated with the AGAGE 2-D 12-box model are significantly higher than most previous emission estimates. The sum of CF4 and C2F6 emissions estimated from aluminum production and non-metal production are lower than observed global top-down emissions, with gaps of ~6 Gg/yr CF4 in recent years. The significant discrepancies between previous CF4, C2F6, and C3F8 emission estimates and observed global top-down emissions estimated from AGAGE measurements emphasize the need for more accurate, transparent, and complete emission reporting, and for verification with atmospheric measurements to assess the emission sources of these long-lived and potent greenhouse gases, which alter the radiative budget of the atmosphere, essentially permanently, once emitted.

  19. High-pressure vapor-liquid equilibria of systems containing ethylene glycol, water and methane - Experimental measurements and modeling

    DEFF Research Database (Denmark)

    Folas, Georgios; Berg, Ole J.; Solbraa, Even


    This work presents new experimental phase equilibrium measurements of the binary MEG-methane and the ternary MEG-water-methane system at low temperatures and high pressures which are of interest to applications related to natural gas processing. Emphasis is given to MEG and water solubility...

  20. Vapor Pressure Plus: An Experiment for Studying Phase Equilibria in Water, with Observation of Supercooling, Spontaneous Freezing, and the Triple Point (United States)

    Tellinghuisen, Joel


    Liquid-vapor, solid-vapor, and solid-liquid-vapor equilibria are studied for the pure substance water, using modern equipment that includes specially fabricated glass cells. Samples are evaporatively frozen initially, during which they typically supercool to -5 to -10 [degrees]C before spontaneously freezing. Vacuum pumping lowers the temperature…

  1. Ionic association and solvation of the ionic liquid 1-hexyl-3-methylimidazolium chloride in molecular solvents revealed by vapor pressure osmometry, conductometry, volumetry, and acoustic measurements. (United States)

    Sadeghi, Rahmat; Ebrahimi, Nosaibah


    A systematic study of osmotic coefficient, conductivity, volumetric and acoustic properties of solutions of ionic liquid 1-hexyl-3-methylimidazolium chloride ([C(6)mim][Cl]) in various molecular solvents has been made at different temperatures in order to study of ionic association and solvation behavior of [C(6)mim][Cl] in different solutions. Precise measurements on electrical conductances of solutions of [C(6)mim][Cl] in water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and acetonitrile at 293.15, 298.15, and 303.15 K are reported and analyzed with Barthel's low-concentration chemical model (lcCM) to obtain the limiting molar conductivities and association constants of this ionic liquid in the investigated solvents. Strong ion pairing was found for the ionic liquid in 2-propanol, 1-butanol, and 1-propanol, whereas ion association in acetonitrile, methanol and ethanol is rather weak and in water the ionic liquid is fully dissociated. In the second part of this work, the apparent molar volumes and isentropic compressibilities of [C(6)mim][Cl] in water, methanol, ethanol, acetonitrile, 1-propanol, 2-propanol, and 1-butanol are obtained at the 288.15-313.15 K temperature range at 5 K intervals at atmospheric pressure from the precise measurements of density and sound velocity. The infinite dilution apparent molar volume and isentropic compressibility values of the free ions and ion pairs of [C(6)mim][Cl] in the investigated solvents as well as the excess molar volume of the investigated solutions are determined and their variations with temperature and type of solvents are also studied. Finally, the experimental measurements of osmotic coefficient at 318.15 K for binary solutions of [C(6)mim][Cl] in water, methanol, ethanol, 2-propanol, and acetonitrile are taken using the vapor pressure osmometry (VPO) method and from which the values of the solvent activity, vapor pressure, activity coefficients, and Gibbs free energies are calculated. The results are

  2. High-pressure vapor-phase hydrodeoxygenation of lignin-derived oxygenates to hydrocarbons by a PtMo bimetallic catalyst: Product selectivity, reaction pathway, and structural characterization

    Energy Technology Data Exchange (ETDEWEB)

    Yohe, Sara L.; Choudhari, Harshavardhan J.; Mehta, Dhairya D.; Dietrich, Paul J.; Detwiler, Michael D.; Akatay, Cem M.; Stach, Eric A.; Miller, Jeffrey T.; Delgass, W. Nicholas; Agrawal, Rakesh; Ribeiro, Fabio H.


    High-pressure, vapor-phase, hydrodeoxygenation (HDO) reactions of dihydroeugenol (2-methoxy-4-propylphenol), as well as other phenolic, lignin-derived compounds, were investigated over a bimetallic platinum and molybdenum catalyst supported on multi-walled carbon nanotubes (5%Pt2.5%Mo/MWCNT). Hydrocarbons were obtained in 100% yield from dihydroeugenol, including 98% yield of the hydrocarbon propylcyclohexane. The final hydrocarbon distribution was shown to be a strong function of hydrogen partial pressure. Kinetic analysis showed three main dihydroeugenol reaction pathways: HDO, hydrogenation, and alkylation. The major pathway occurred via Pt catalyzed hydrogenation of the aromatic ring and methoxy group cleavage to form 4-propylcyclohexanol, then Mo catalyzed removal of the hydroxyl group by dehydration to form propylcyclohexene, followed by hydrogenation of propylcyclohexene on either the Pt or Mo to form the propylcyclohexane. Transalkylation by the methoxy group occurred as a minor side reaction. Catalyst characterization techniques including chemisorption, scanning transmission electron microscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy were employed to characterize the catalyst structure. Catalyst components identified were Pt particles, bimetallic PtMo particles, a Mo carbide-like phase, and Mo oxide phases.

  3. Novel chemical vapor deposition process of ZnO films using nonequilibrium N2 plasma generated near atmospheric pressure with small amount of O2 below 1% (United States)

    Nose, Yukinori; Yoshimura, Takeshi; Ashida, Atsushi; Uehara, Tsuyoshi; Fujimura, Norifumi


    We propose a novel chemical vapor deposition (CVD) process of ZnO films involving a nonequilibrium N2 plasma generated near atmospheric pressure with small O2 concentration (O2%) below 1%. In the optical emission (OE) spectra of the plasma, OE lines corresponding to the NO-γ system ( A 2 Σ + → X 2 Πγ + ) were observed, despite the only introduced gases being N2 and O2; these vanish at an O2% of more than 1%. ZnO films were grown on a glass substrate placed in the plasma at a growth temperature of as low as 200 °C and at an O2% of below 1% in the presence of the NO-γ system. This plasma yielded almost the same growth rate for ZnO films as O2 plasma including atomic O radicals that are often observed in low-pressure O2 plasma, suggesting that some highly reactive oxidant was sufficiently generated in such a small O2%. ZnO films synthesized using this plasma exhibited excellent ( 0001 ) preferred orientation without other diffractions such as 10 1 ¯ 1 diffraction, and with an optical bandgap of 3.30 eV. Based on the analyses of the plasma and the exhaust gases, the coexistence state of NO-γ and O3 should be essential and useful for the decomposition and oxidation of Zn source material in the proposed CVD process.

  4. Effect of water vapor on plasma morphology, OH and H2O2 production in He and Ar atmospheric pressure dielectric barrier discharges (United States)

    Du, Yanjun; Nayak, Gaurav; Oinuma, Gaku; Peng, Zhimin; Bruggeman, Peter J.


    Although atmospheric pressure dielectric barrier discharges (DBDs) have a long history, the effects of water vapor on the discharge morphology and kinetics have not been studied intensively. We report a simultaneous investigation of discharge morphology, OH and H2O2 production in Ar and He DBDs operated at different water vapor concentrations and powers. The combined study allows us to assess the impact of the discharge morphology and power on the concentration dependence of the OH and H2O2 production. The morphology of the discharge is investigated by ICCD images and current-voltage waveforms. These diagnostics are complemented by broadband absorption and a colorimetric method to measure the gas temperature and the OH and H2O2 concentrations. The number of filaments in Ar DBD increases with increasing water concentration and power. The surface discharge part of the micro-discharge also reduces with increasing water concentration most likely due to a change in surface conductivity of the dielectric with changing water concentration. The OH density in the case of Ar is approximately double the OH density in He for similar power and water admixture. In contrast to the root square dependence of the OH density on the water concentration in He similar to diffuse RF discharges, the OH density in Ar increases for small water concentrations followed by a saturation and reduces for higher water concentrations. This dependence of OH density on water concentration is found to correlate with changes in discharge morphology. An analytical balance of the production and destruction mechanism of H2O2 is shown to be able to reproduce the ratio of the measured OH and H2O2 density for realistic values of electron densities.

  5. Optical Sensor for Diverse Organic Vapors at ppm Concentration Ranges

    Directory of Open Access Journals (Sweden)

    Dora M. Paolucci


    Full Text Available A broadly responsive optical organic vapor sensor is described that responds to low concentrations of organic vapors without significant interference from water vapor. Responses to several classes of organic vapors are highlighted, and trends within classes are presented. The relationship between molecular properties (vapor pressure, boiling point, polarizability, and refractive index and sensor response are discussed.

  6. Vaporization and configuration effects in a high-pressure/high-temperature combustor equipped with multiple Venturi-type fuel injectors (United States)

    Locke, Randy J.; Chun, K. S.; Lee, C. M.; Ratvasky, William J.


    The flow field and fuel/air mixing patterns produced in an optically accessible, premixing/prevaporization section of a high pressure/high temperature combustor were examined via focused Schlieren high-speed photography. A focal plane, approximately 8 mm thick and centered within this section downstream of the fuel injectors, was imaged at a framing rate of 8,000 frames/second. High-speed focused Schlieren images were obtained for three different Venturi-type fuel injector configurations under identical experimental parameters. The results demonstrate the efficacy of this technique to discern fuel spray patternization, fuel-air mixing efficiencies, and mixing times of various fuel injector arrangements.

  7. Does vapor pressure deficit drive the seasonality of δ13C of the net land-atmosphere CO2 exchange across the United States? (United States)

    Raczka, B.; Biraud, S. C.; Ehleringer, J. R.; Lai, C.-T.; Miller, J. B.; Pataki, D. E.; Saleska, S. R.; Torn, M. S.; Vaughn, B. H.; Wehr, R.; Bowling, D. R.


    The seasonal pattern of the carbon isotope content (δ13C) of atmospheric CO2 depends on local and nonlocal land-atmosphere exchange and atmospheric transport. Previous studies suggested that the δ13C of the net land-atmosphere CO2 flux (δsource) varies seasonally as stomatal conductance of plants responds to vapor pressure deficit of air (VPD). We studied the variation of δsource at seven sites across the United States representing forests, grasslands, and an urban center. Using a two-part mixing model, we calculated the seasonal δsource for each site after removing background influence and, when possible, removing δ13C variation of nonlocal sources. Compared to previous analyses, we found a reduced seasonal (March-September) variation in δsource at the forest sites (0.5‰ variation). We did not find a consistent seasonal relationship between VPD and δsource across forest (or other) sites, providing evidence that stomatal response to VPD was not the cause of the global, coherent seasonal pattern in δsource. In contrast to the forest sites, grassland and urban sites had a larger seasonal variation in δsource (5‰) dominated by seasonal transitions in C3/C4 grass productivity and in fossil fuel emissions, respectively. Our findings were sensitive to the location used to account for atmospheric background variation within the mixing model method that determined δsource. Special consideration should be given to background location depending on whether the intent is to understand site level dynamics or regional scale impacts of land-atmosphere exchange. The seasonal amplitude in δ13C of land-atmosphere CO2 exchange (δsource) varied across land cover types and was not driven by seasonal changes in vapor pressure deficit. The largest seasonal amplitudes of δsource were at grassland and urban sites, driven by changes in C3/C4 grass productivity and fossil fuel emissions, respectively. Mixing model approaches may incorrectly calculate δsource when

  8. Perfluorocarbon Nanoparticles as Delivery Vehicles for Melittin and Its Protease-Activated Derivatives (United States)

    Jallouk, Andrew Philip

    Melittin is a cytolytic peptide derived from honeybee venom which inserts into lipid membranes and oligomerizes to form membrane pores. While this peptide is an attractive candidate for treatment of cancers and infectious processes, its nonspecific cytotoxicity and hemolytic activity have limited its therapeutic applications. The goal of this dissertation was to enhance the specificity of melittin therapy through the use of perfluorocarbon nanoparticles to minimize nonspecific cytotoxicity and the development of melittin prodrugs which only exhibit cytolytic activity following activation by site-specific proteases. Although previous studies have characterized the biological effects of melittin-loaded nanoparticles following intravenous administration, we first investigated their use as topical agents for prevention of HIV infection. We found that incorporation of native melittin onto perfluorocarbon nanoparticles maintained antiviral activity while substantially reducing contact toxicity to sperm and vaginal epithelium. These results demonstrated the potential utility of melittin-loaded nanoparticles as a topical vaginal virucide. To further enhance melittin specificity, we developed melittin derivatives which could be activated by matrix metalloproteinase-9, a protease which is overexpressed in many tumors and which plays a critical role in cancer invasion and metastasis. We then characterized the interactions of these peptides with perfluorocarbon nanoparticles and demonstrated the safety and efficacy of intravenous prodrug-loaded nanoparticle therapy in a mouse model of melanoma. The versatility of this platform could facilitate development of personalized cancer therapies directed towards a patient's individual protease expression profile.

  9. Regulation of Vapor Pressure Deficit by Greenhouse Micro-Fog Systems Improved Growth and Productivity of Tomato via Enhancing Photosynthesis during Summer Season.

    Directory of Open Access Journals (Sweden)

    Dalong Zhang

    Full Text Available The role of a proposed micro-fog system in regulating greenhouse environments and enhancing tomato (Solanum lycopersicum L. productivity during summer season was studied. Experiments were carried out in a multi-span glass greenhouse, which was divided into two identical compartments involving different environments: (1 without environment control and (2 with a micro-fog system operating when the air vapor pressure deficit (VPD of greenhouse was higher than 0.5 KPa. The micro-fog system effectively alleviated heat stress and evaporative demand in the greenhouse during summer season. The physiologically favourable environment maintained by micro-fog treatment significantly enhanced elongation of leaf and stem, which contributed to a substantial elevation of final leaf area and shoot biomass. These improvements in physiological and morphological traits resulted in around 12.3% increase of marketable tomato yield per plant. Relative growth rate (RGR of micro-fog treatment was also significantly higher than control plants, which was mainly determined by the substantial elevation in net assimilation rate (NAR, and to a lesser extent caused by leaf area ratio (LAR. Measurement of leaf gas exchange parameters also demonstrated that micro-fog treatment significantly enhanced leaf photosynthesis capacity. Taken together, manipulation of VPD in greenhouses by micro-fog systems effectively enhanced tomato growth and productivity via improving photosynthesis during summer season.

  10. Si{sub 3}N{sub 4} coating for improvement of anti-oxidation and anti-wear properties by low pressure chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Yun; Kim, Ok Hee; Park, Chong Ook [Korea Advanced Inst. of Science and Technology, Taejeon (Korea, Republic of); Yeh, Byung Hahn; Jung, Bahl [Agency of Defence Development, Taejon (Korea, Republic of)


    The deposition properties of Si{sub 3}N{sub 4} deposited by low pressure chemical vapor deposition were studied to evaluate Si{sub 3}N{sub 4} as part of multi-layer coatings for anti-oxidation and anti-wear coating of graphite in the propellant-burning environment. Si{sub 3}N{sub 4} was deposited on the pack-SiC coated graphite and the tendencies of deposition rate and surface morphology changes with temperatures and reaction gas ratios were investigated. In low deposition temperatures the deposition rate increased with increasing temperature but in high temperatures the deposition rate decreased with increasing temperature. The grain size of Si{sub 3}N{sub 4} decreased with increasing temperature. In condition that the range of reaction gas ratios is 20 {<=} NH{sub 3}/SiH{sub 4} {<=} 40, the deposition rate and surface morphology did not change. The Si{sub 3}N{sub 4} deposited at 800-1300 degree was amorphous, and by post-annealing at 1300 degree in N{sub 2} ambient, the Si{sub 3}N{sub 4} crystallized. (author). 15 refs., 10 figs.

  11. Doping characteristics of Si-doped n-GaN Epilayers grown by low-pressure metal-organic chemical-vapor deposition

    CERN Document Server

    Noh, S K; Park, S E; Lee, I H; Choi, I H; Son, S J; Lim, K Y; Lee, H J


    We studied doping behaviors through analysis of the electronic properties of a series of undoped and Si-doped GaN epilayers grown on (0001) sapphire substrates by the low-pressure metal-organic chemical-vapor deposition (LP-MOCVD) technique. The doping efficiency was in the range of 0.4 - 0.8, and an empirical relation expressed as eta = 0.45 log[Si] - 8.1 was obtained. The temperature dependence of carrier concentration showed that the donor activation energy monotonically decreased from 17.6 meV to almost zero as the doping level increased. We suggest that the reduction in the activation energy is related not to autodoped defect centers but to doped Si donors and that the behavior originates from the formation of an impurity band. On the basis of an abrupt change in the compensation ratio from 0.9 to 0.5 by Si-doping, an exceptional difference in the Hall mobility between the undoped and the Si-doped films is explained by a mixed conduction mechanism of electrons and holes.

  12. Strained In1-xGaxAsyP1-y/InP quantum well heterostructures grown by low-pressure metalorganic vapor phase epitaxy

    Directory of Open Access Journals (Sweden)

    Carvalho Jr Wilson de


    Full Text Available We have investigated the optical and the structural properties of strained In1-xGaxAsyP1-y/InP and strain compensated In1-xGaxAsyP1-y/In1-zGazAsqP1-q/InP multi-quantum well heterostructures grown by low-pressure metalorganic vapor phase epitaxy at different growth conditions. Our results indicate an increase of the compositional fluctuation of quaternary materials as the alloy composition moves from the outer spinodal isotherm into the miscibility gap region. In1-xGaxAsyP1-y layers grown at high tensile strained values exhibit a three-dimensional-like growth mode. Strain compensated structures revealed the presence of a broad photoluminescence emission band below the fundamental quantum well transition, well defined elongated features along the [011] direction and interface undulations. All these effects were found to be strongly dependent on the growth temperature and the number of wells.

  13. Molecular-dynamics evaluation of fluid-phase equilibrium properties by a novel free-energy perturbation approach: application to gas solubility and vapor pressure of liquid hexane. (United States)

    Kuwajima, Satoru; Kikuchi, Hiroaki; Fukuda, Mitsuhiro


    A novel free-energy perturbation method is developed for the computation of the free energy of transferring a molecule between fluid phases. The methodology consists in drawing a free-energy profile of the target molecule moving across a binary-phase structure built in the computer. The novelty of the method lies in the difference of the definition of the free-energy profile from the common definition. As an important element of the method, the process of making a correction to the transfer free energy with respect to the cutoff of intermolecular forces is elucidated. In order to examine the performance of the method in the application to fluid-phase equilibrium properties, molecular-dynamics computations are carried out for the evaluation of gas solubility and vapor pressure of liquid n-hexane at 298.15 K. The gas species treated are methane, ethane, propane, and n-butane, with the gas solubility expressed as Henry's constant. It is shown that the method works fine and calculated results are generally in good agreement with experiments. It is found that the cutoff correction is strikingly large, constituting a dominant part of the calculated transfer free energy at the cutoff of 8 A.

  14. Liquid-vapor equilibrium of the systems butylmethylimidazolium nitrate-CO2 and hydroxypropylmethylimidazolium nitrate-CO2 at high pressure: influence of water on the phase behavior. (United States)

    Bermejo, M Dolores; Montero, Marta; Saez, Elisa; Florusse, Louw J; Kotlewska, Aleksandra J; Cocero, M José; van Rantwijk, Fred; Peters, Cor J


    Ionic liquids (IL) are receiving increasing attention due to their potential as "green" solvents, especially when used in combination with SC-CO2. In this work liquid-vapor equilibria of binary mixtures of CO2 with two imidazolium-based ionic liquids (IL) with a nitrate anion have been experimentally determined: butylmethylimidazolium nitrate (BMImNO3) and hydroxypropylmethylimidazolium nitrate (HOPMImNO3), using a Cailletet apparatus that operates according to the synthetic method. CO2 concentrations from 5 up to 30 mol % were investigated. It was found that CO2 is substantially less soluble in HOPMImNO3 than in BMImNO3. Since these ILs are very hygroscopic, water easily can be a major contaminant, causing changes in the phase behavior. In case these Ils are to be used in practical applications, for instance, together with CO2 as a medium in supercritical enzymatic reactions, it is very important to have quantitative information on how the water content will affect the phase behavior. This work presents the first systematic study on the influence of water on the solubility of carbon dioxide in hygroscopic ILs. It was observed that the presence of water reduces the absolute solubility of CO2. However, at fixed ratios of CO2/IL, the bubble point pressure remains almost unchanged with increasing water content. In order to explain the experimental results, the densities of aqueous mixtures of both ILs were determined experimentally and the excess molar volumes calculated.

  15. The photosynthetic response of tobacco plants overexpressing ice plant aquaporin McMIPB to a soil water deficit and high vapor pressure deficit. (United States)

    Kawase, Miki; Hanba, Yuko T; Katsuhara, Maki


    We investigated the photosynthetic capacity and plant growth of tobacco plants overexpressing ice plant (Mesembryanthemum crystallinum L.) aquaporin McMIPB under (1) a well-watered growth condition, (2) a well-watered and temporal higher vapor pressure deficit (VPD) condition, and (3) a soil water deficit growth condition to investigate the effect of McMIPB on photosynthetic responses under moderate soil and atmospheric humidity and water deficit conditions. Transgenic plants showed a significantly higher photosynthesis rate (by 48 %), higher mesophyll conductance (by 52 %), and enhanced growth under the well-watered growth condition than those of control plants. Decreases in the photosynthesis rate and stomatal conductance from ambient to higher VPD were slightly higher in transgenic plants than those in control plants. When plants were grown under the soil water deficit condition, decreases in the photosynthesis rate and stomatal conductance were less significant in transgenic plants than those in control plants. McMIPB is likely to work as a CO2 transporter, as well as control the regulation of stomata to water deficits.

  16. Enhancement of the Stomatal Response to Blue Light by Red Light, Reduced Intercellular Concentrations of CO(2), and Low Vapor Pressure Differences. (United States)

    Assmann, S M


    The effects of environmental parameters on the blue light response of stomata were studied by quantifying transient increases in stomatal conductance in Commelina communis following 15 seconds by 0.100 millimole per square meter per second pulses of blue light. Because conductance increases were not observed following red light pulses of the same or greater (30 seconds by 0.200 millimole per square meter per second) fluences, the responses observed could be reliably attributed to the specific blue light response of the guard cells, rather than to guard cell chlorophyll. In both Paphiopedilum harrisianum, which lacks guard cell chloroplasts, and Commelina, the blue light response was enhanced by 0.263 millimole per square meter per second continuous background red light. Thus, the blue light response and its enhancement do not require energy derived from red-light-driven photophosphorylation by the guard cell chloroplasts. In Commelina, reduction of the intercellular concentration of CO(2) by manipulation of ambient CO(2) concentrations resulted in an enhanced blue light response. In both Commelina and Paphiopedilum, the blue light response was decreased by an increased vapor pressure difference. The magnitude of blue-light-specific stomatal opening thus appears to be sensitive to environmental conditions that affect the carbon and water status of the plant.

  17. Enhancement of the Stomatal Response to Blue Light by Red Light, Reduced Intercellular Concentrations of CO2, and Low Vapor Pressure Differences 1 (United States)

    Assmann, Sarah M.


    The effects of environmental parameters on the blue light response of stomata were studied by quantifying transient increases in stomatal conductance in Commelina communis following 15 seconds by 0.100 millimole per square meter per second pulses of blue light. Because conductance increases were not observed following red light pulses of the same or greater (30 seconds by 0.200 millimole per square meter per second) fluences, the responses observed could be reliably attributed to the specific blue light response of the guard cells, rather than to guard cell chlorophyll. In both Paphiopedilum harrisianum, which lacks guard cell chloroplasts, and Commelina, the blue light response was enhanced by 0.263 millimole per square meter per second continuous background red light. Thus, the blue light response and its enhancement do not require energy derived from red-light-driven photophosphorylation by the guard cell chloroplasts. In Commelina, reduction of the intercellular concentration of CO2 by manipulation of ambient CO2 concentrations resulted in an enhanced blue light response. In both Commelina and Paphiopedilum, the blue light response was decreased by an increased vapor pressure difference. The magnitude of blue-light-specific stomatal opening thus appears to be sensitive to environmental conditions that affect the carbon and water status of the plant. PMID:16666108

  18. Passive Vaporizing Heat Sink (United States)

    Knowles, TImothy R.; Ashford, Victor A.; Carpenter, Michael G.; Bier, Thomas M.


    A passive vaporizing heat sink has been developed as a relatively lightweight, compact alternative to related prior heat sinks based, variously, on evaporation of sprayed liquids or on sublimation of solids. This heat sink is designed for short-term dissipation of a large amount of heat and was originally intended for use in regulating the temperature of spacecraft equipment during launch or re-entry. It could also be useful in a terrestrial setting in which there is a requirement for a lightweight, compact means of short-term cooling. This heat sink includes a hermetic package closed with a pressure-relief valve and containing an expendable and rechargeable coolant liquid (e.g., water) and a conductive carbon-fiber wick. The vapor of the liquid escapes when the temperature exceeds the boiling point corresponding to the vapor pressure determined by the setting of the pressure-relief valve. The great advantage of this heat sink over a melting-paraffin or similar phase-change heat sink of equal capacity is that by virtue of the =10x greater latent heat of vaporization, a coolant-liquid volume equal to =1/10 of the paraffin volume can suffice.

  19. Fuel Vaporization Effects (United States)

    Bosque, M. A.


    A study of the effects of fuel-air preparation characteristics on combustor performance and emissions at temperature and pressure ranges representative of actual gas turbine combustors is discussed. The effect of flameholding devices on the vaporization process and NOx formation is discussed. Flameholder blockage and geometry are some of the elements that affect the recirculation zone characteristics and subsequently alter combustion stability, emissions and performance. A water cooled combustor is used as the test rig. Preheated air and Jet A fuel are mixed at the entrance of the apparatus. A vaporization probe is used to determine percentage of vaporization and a gas sample probe to determine concentration of emissions in the exhaust gases. The experimental design is presented and experimental expected results are discussed.

  20. Raman study of light-emitting SiN{sub x} films grown on Si by low-pressure chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Komarov, F. [A.N. Sevchenko Institute of Applied Physics Problems, Kurchatov Str. 7, 220045 Minsk (Belarus); Vlasukova, L. [Belarusian State University, Nezavisimosty Ave. 4, 220030 Minsk (Belarus); Parkhomenko, I., E-mail: [Belarusian State University, Nezavisimosty Ave. 4, 220030 Minsk (Belarus); Milchanin, O. [A.N. Sevchenko Institute of Applied Physics Problems, Kurchatov Str. 7, 220045 Minsk (Belarus); Mudryi, A. [Scientific and Practical Materials Research Center, National Academy of Sciences of Belarus, P. Brovki Str. 17, 220072 Minsk (Belarus); Togambaeva, A. [Al-Farabi Kazakh National University, Al-Farabiy Ave. 71, 050038 Almaty (Kazakhstan); Korolik, O. [Belarusian State University, Nezavisimosty Ave. 4, 220030 Minsk (Belarus)


    Si-rich silicon nitride (SRSN) films were deposited on Si wafers by low pressure chemical vapor deposition (LPCVD) technique and, subsequently, annealed at (800–1200) °C to form Si precipitates. The composition of SiN{sub x} films was measured by Rutherford backscattering spectrometry (RBS). Two sets of samples differed by the amount of excessive Si (Si{sub exc}) in silicon nitride were studied. Evolution of Si nanoclusters from amorphous to crystalline ones during high temperature treatment was examined by Raman scattering (RS) spectroscopy. The amorphous Si clusters were already revealed in as-deposited SiN{sub x} while the annealing results in their crystallization. The crystalline nanoprecipitates are only registered in nitride films after annealing at 1200 °C. A dependence of Raman scattering intensity from the Si wafer on the temperature of annealing of SiN{sub x}/Si structures was revealed. This information was used to explain the phase transformations in SRSNs during high temperature treatments. The peculiarities of photoluminescence (PL) spectra for two sets of Si-rich SiN{sub x} films are explained taking into account the contribution from the quantum confinement effect of Si nanocrystals and from the native defects in silicon nitride matrix, such as N- and K-centers. - Highlights: • The size of Si nanocrystals in Si-rich SiN{sub x} films depends on Si excess content. • Excess Si remains in SiN{sub 0.46} as randomly distributed Si atoms in atomic network. • In SiN{sub 1} films practically all excess Si is aggregated into Si nanoclusters.

  1. Atmospheric-pressure plasma-enhanced chemical vapor deposition of a-SiCN:H films: role of precursors on the film growth and properties. (United States)

    Guruvenket, Srinivasan; Andrie, Steven; Simon, Mark; Johnson, Kyle W; Sailer, Robert A


    Atmospheric pressure plasma enhanced chemical vapor deposition (AP-PECVD) using Surfx Atomflow(TM) 250D APPJ was utilized to synthesize amorphous silicon carbonitride coatings using tetramethyldisilizane (TMDZ) and hexamethyldisilizane (HMDZ) as the single source precursors. The effect of precursor chemistry and substrate temperature (T(s)) on the properties of a-SiCN:H films were evaluated, while nitrogen was used as the reactive gas. Surface morphology of the films was evaluated using atomic force microscopy (AFM); chemical properties were determined using Fourier transform infrared spectroscopy (FTIR); thickness and optical properties were determined using spectroscopic ellipsometry and mechanical properties were determined using nanoindentation. In general, films deposited at substrate temperature (T(s)) films deposited at T(s) > 200 °C depicted strong Si-N and Si-CN absorption. Refractive indices (n) of the thin films showed values between 1.5 and 2.0, depending on the deposition parameters. Mechanical properties of the films determined using nanoindentation revealed that these films have hardness between 0.5 GPa and 15 GPa, depending on the T(s) value. AFM evaluation of the films showed high roughness (R(a)) values of 2-3 nm for the films grown at low T(s) (films grown at T(s) ≥ 300 °C exhibited atomically smooth surface with R(a) of ~0.5 nm. Based on the gas-phase (plasma) chemistry, precursor chemistry and the other experimental observations, a possible growth model that prevails in the AP-PECVD of a-SiCN:H thin films is proposed.

  2. Volatilization of low vapor pressure--volatile organic compounds (LVP-VOCs) during three cleaning products-associated activities: Potential contributions to ozone formation. (United States)

    Shin, Hyeong-Moo; McKone, Thomas E; Bennett, Deborah H


    There have been many studies to reduce ozone formation mostly from volatile organic compound (VOC) sources. However, the role of low vapor pressure (LVP)-VOCs from consumer products remains mostly unexplored and unaddressed. This study explores the impact of high production volume LVP-VOCs on ozone formation from three cleaning products-associated activities (dishwashing, clothes washing, and surface cleaning). We develop a model framework to account for the portion available for ozone formation during the use phase and from the down-the-drain disposal. We apply experimental studies that measured emission rates or models that were developed for estimating emission rates of organic compounds during the use phase. Then, the fraction volatilized (fvolatilized) and the fraction disposed down the drain (fdown-the-drain) are multiplied by the portion available for ozone formation for releases to the outdoor air (fO3|volatilized) and down-the-drain (fO3|down-the-drain), respectively. Overall, for chemicals used in three specific cleaning-product uses, fvolatilized is less than 0.6% for all studied LVP-VOCs. Because greater than 99.4% of compounds are disposed of down the drain during the use phase, when combined with fO3|volatilized and fO3|down-the-drain, the portion available for ozone formation from the direct releases to outdoor air and the down-the-drain disposal is less than 0.4% and 0.2%, respectively. The results from this study indicate that the impact of the studied LVP-VOCs on ozone formation is very sensitive to what occurs during the use phase and suggest the need for future research on experimental work at the point of use. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. GeSn growth kinetics in reduced pressure chemical vapor deposition from Ge2H6 and SnCl4 (United States)

    Aubin, J.; Hartmann, J. M.


    We have investigated the low temperature epitaxy of high Sn content GeSn alloys in a 200 mm industrial Reduced Pressure - Chemical Vapor Deposition tool from Applied Materials. Gaseous digermane (Ge2H6) and liquid tin tetrachloride (SnCl4) were used as the Ge and Sn precursors, respectively. The impact of temperature (in the 300-350 °C range), Ge2H6 and SnCl4 mass-flows on the GeSn growth kinetics at 100 Torr has been thoroughly explored. Be it at 300 °C or 325 °C, a linear GeSn growth rate increase together with a sub-linear Sn concentration increase occurred as the SnCl4 mass-flow increased, irrespective of the Ge2H6 mass flow (fixed or varying). The Sn atoms seemed to catalyze H desorption from the surface, resulting in higher GeSn growth rates for high SnCl4 mass-flows (in the 4-21 nm min-1 range). The evolution of the Sn content x with the F (SnCl4) 2 ·/F (Ge2H6) mass-flow ratio was fitted by x2/(1 - x) = n ·F (SnCl4) 2 ·/F (Ge2H6), with n = 0.25 (325 °C) and 0.60 (300 °C). We have otherwise studied the impact of temperature, in the 300-350 °C range, on the GeSn growth kinetics. The GeSn growth rate exponentially increased with the temperature, from 15 up to 32 nm min-1. The associated activation energy was low, i.e. Ea = 10 kcal mol-1. Meanwhile, the Sn content decreased linearly as the growth temperature increased, from 15% at 300 °C down to 6% at 350 °C.

  4. Electrochemical performance of LiFePO{sub 4} modified by pressure-pulsed chemical vapor infiltration in lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li Jianling [Department of Physical Chemistry, University of Science and Technology Beijing, No. 30 College Road, Haidian District, Beijing 100083 (China); Department of Applied Chemistry, Aichi Institute of Technology, Yachigusa 1247, Yakusa-cho, Toyota 470-0392 (Japan)], E-mail:; Suzuki, Tomohiro; Naga, Kazuhisa; Ohzawa, Yoshimi; Nakajima, Tsuyoshi [Department of Applied Chemistry, Aichi Institute of Technology, Yachigusa 1247, Yakusa-cho, Toyota 470-0392 (Japan)


    Using the pressure-pulsed chemical vapor infiltration (PCVI) technique, pyrolytic carbon (pyrocarbon) films were deposited on the surface of LiFePO{sub 4} particles for cathode material of lithium-ion batteries. The electrochemical performance of the original LiFePO{sub 4} and PCVIed LiFePO{sub 4} materials was evaluated using a three electrodes cell by galvanostatic charging/discharging at 25, 40 and 55 deg. C, respectively. Morphology and structure of LiFePO{sub 4} were analyzed by SEM, XRD and Raman. The resulting carbon contents at 500, 1000, 2000, 3000 and 5000 pulses were 2.7, 4.7, 9.5, 15.1 and 19.4%, respectively and these samples were abbreviated as 500P, 1000P, 2000P, 3000P and 5000P, respectively. All the PCVIed samples exhibited excellent rate performance. The tendency was more and more obvious with the increase of the current densities. The specific capacities of 500P, 1000P and 2000P were maintained at 117, 124 and 132 mAh g{sup -1}, respectively, which were 120.8, 264.7 and 29.47% larger than those of corresponding original LiFePO{sub 4}, respectively, at a 5C rate at 55 deg. C. The EIS measurement showed that electrochemical reaction resistance (R{sub ct}) of PCVIed LiFePO{sub 4} were obviously decreased, indicating a fast kinetics compared to the original LiFePO{sub 4}. The cycle ability of the 2000P sample was tested at 25 deg. C and C/2 rate. The cell was cycled for 150 cycles and no obviously capacity fade was observed. Its specific capacity of 115 mAh g{sup -1} at 150th cycle is 1.7 times higher than that of original LiFePO{sub 4}.

  5. Halogenated methyl-phenyl ethers (anisoles) in the environment: determination of vapor pressures, aqueous solubilities, Henry's law constants, and gas/water- (Kgw), n-octanol/water- (Kow) and gas/n-octanol (Kgo) partition coefficients. (United States)

    Pfeifer, O; Lohmann, U; Ballschmiter, K


    Halogenated methyl-phenyl ethers (methoxybenzenes, anisoles) are ubiquitous organics in the environment although they are not produced in industrial quantities. Modelling the fate of organic pollutants such as halogenated anisoles requires a knowledge of the fundamental physico-chemical properties of these compounds. The isomer-specific separation and detection of 60 of the 134 possible congeners allowing an environmental fingerprinting are reported in this study. The vapor pressure p0(L) of more than 60 and further physico-chemical properties of 26 available congeners are given. Vapor pressures p0(L), water solubilities S(L)W, and n-octanol/water partition coefficients Kow were determined by capillary HR-GC (High Resolution Gas Chromatography) on a non-polar phase and by RP-HPLC (Reversed Phase High Performance Liquid Chromatography) on a C18 phase with chlorobenzenes as reference standards. From these experimental data the Henry's law constants H, and the gas/water Kgw and gas/n-octanol Kgo partition coefficients were calculated. We found that vapor pressures, water solubilities, and n-octanol/water partition coefficients of the halogenated anisoles are close to those of the chlorobenzenes. A similar environmental fate of both groups can, therefore, be predicted.

  6. Observation of vapor pressure enhancement of rare-earth metal-halide salts in the temperature range relevant to metal-halide lamps (United States)

    Curry, J. J.; Estupiñán, E. G.; Lapatovich, W. P.; Henins, A.; Shastri, S. D.; Hardis, J. E.


    Total vapor-phase densities of Dy in equilibrium with a DyI3/InI condensate and Tm in equilibrium with a TmI3/TlI condensate have been measured for temperatures between 900 K and 1400 K. The measurements show strong enhancements in rare-earth vapor densities compared to vapors in equilibrium with the pure rare-earth metal-halides. The measurements were made with x-ray induced fluorescence on the sector 1-ID beam line at the Advanced Photon Source. The temperature range and salt mixtures are relevant to the operation of metal-halide high-intensity discharge lamps.

  7. In vitro surfactant and perfluorocarbon aerosol deposition in a neonatal physical model of the upper conducting airways.

    Directory of Open Access Journals (Sweden)

    Estibalitz Goikoetxea

    Full Text Available OBJECTIVE: Aerosol delivery holds potential to release surfactant or perfluorocarbon (PFC to the lungs of neonates with respiratory distress syndrome with minimal airway manipulation. Nevertheless, lung deposition in neonates tends to be very low due to extremely low lung volumes, narrow airways and high respiratory rates. In the present study, the feasibility of enhancing lung deposition by intracorporeal delivery of aerosols was investigated using a physical model of neonatal conducting airways. METHODS: The main characteristics of the surfactant and PFC aerosols produced by a nebulization system, including the distal air pressure and air flow rate, liquid flow rate and mass median aerodynamic diameter (MMAD, were measured at different driving pressures (4-7 bar. Then, a three-dimensional model of the upper conducting airways of a neonate was manufactured by rapid prototyping and a deposition study was conducted. RESULTS: The nebulization system produced relatively large amounts of aerosol ranging between 0.3±0.0 ml/min for surfactant at a driving pressure of 4 bar, and 2.0±0.1 ml/min for distilled water (H2Od at 6 bar, with MMADs between 2.61±0.1 µm for PFD at 7 bar and 10.18±0.4 µm for FC-75 at 6 bar. The deposition study showed that for surfactant and H2Od aerosols, the highest percentage of the aerosolized mass (∼65% was collected beyond the third generation of branching in the airway model. The use of this delivery system in combination with continuous positive airway pressure set at 5 cmH2O only increased total airway pressure by 1.59 cmH2O at the highest driving pressure (7 bar. CONCLUSION: This aerosol generating system has the potential to deliver relatively large amounts of surfactant and PFC beyond the third generation of branching in a neonatal airway model with minimal alteration of pre-set respiratory support.

  8. In Vitro Surfactant and Perfluorocarbon Aerosol Deposition in a Neonatal Physical Model of the Upper Conducting Airways (United States)

    Goikoetxea, Estibalitz; Murgia, Xabier; Serna-Grande, Pablo; Valls-i-Soler, Adolf; Rey-Santano, Carmen; Rivas, Alejandro; Antón, Raúl; Basterretxea, Francisco J.; Miñambres, Lorena; Méndez, Estíbaliz; Lopez-Arraiza, Alberto; Larrabe-Barrena, Juan Luis; Gomez-Solaetxe, Miguel Angel


    Objective Aerosol delivery holds potential to release surfactant or perfluorocarbon (PFC) to the lungs of neonates with respiratory distress syndrome with minimal airway manipulation. Nevertheless, lung deposition in neonates tends to be very low due to extremely low lung volumes, narrow airways and high respiratory rates. In the present study, the feasibility of enhancing lung deposition by intracorporeal delivery of aerosols was investigated using a physical model of neonatal conducting airways. Methods The main characteristics of the surfactant and PFC aerosols produced by a nebulization system, including the distal air pressure and air flow rate, liquid flow rate and mass median aerodynamic diameter (MMAD), were measured at different driving pressures (4–7 bar). Then, a three-dimensional model of the upper conducting airways of a neonate was manufactured by rapid prototyping and a deposition study was conducted. Results The nebulization system produced relatively large amounts of aerosol ranging between 0.3±0.0 ml/min for surfactant at a driving pressure of 4 bar, and 2.0±0.1 ml/min for distilled water (H2Od) at 6 bar, with MMADs between 2.61±0.1 µm for PFD at 7 bar and 10.18±0.4 µm for FC-75 at 6 bar. The deposition study showed that for surfactant and H2Od aerosols, the highest percentage of the aerosolized mass (∼65%) was collected beyond the third generation of branching in the airway model. The use of this delivery system in combination with continuous positive airway pressure set at 5 cmH2O only increased total airway pressure by 1.59 cmH2O at the highest driving pressure (7 bar). Conclusion This aerosol generating system has the potential to deliver relatively large amounts of surfactant and PFC beyond the third generation of branching in a neonatal airway model with minimal alteration of pre-set respiratory support. PMID:25211475

  9. Vapor Pressure of Ammonium Perchlorate (United States)

    data indicate that ammonium perchlorate sublimes by the dissociation process NH4ClO4 sub (s) = NH3 sub (g) + HClO4 sub (g). The heat of dissociation has been found to be 58 + or - 2 kcal/mole in the cited temperature range.

  10. Vapor Pressure of Antimony Triiodide (United States)


    Te,Se)3 crystal lattice during subsequent solidification and Bridgman crystal growth. Substitutional Sb is isoelectronic on a bismuth (Bi) site and... lattice during growth. If one assumes unity incorporation (i.e., one I becomes incorporated from one SbI3 molecule that hits the surface), then a...J Appl Physics. 1999;85:7807. 3. Mzerd A, Sayah D, Tedenac JC , Boyer A. Optimal crystal growth conditions of thin films of BiTe semiconductors. J

  11. Surfactant and perfluorocarbon aerosolization by means of inhalation catheters for the treatment of respiratory distress syndrome: an in vitro study. (United States)

    Murgia, Xabier; Gastiasoro, Elena; Mielgo, Victoria; Alvarez-Diaz, Francisco; Lafuente, Hector; Valls-i-Soler, Adolf; Gomez-Solaetxe, Miguel Angel; Larrabe, Juan Luis; Rey-Santano, Carmen


    The aerosolization of perfluorocarbons or surfactant has emerged as a feasible alternative to instillation, for the treatment of experimental respiratory distress syndrome. However, the biophysical properties that make these compounds useful in such therapies, significantly affect the performance of nebulizers. Therefore, in vitro studies are required to assess the suitability of new aerosolization technologies for use with these compounds. The aim of the present in vitro study was to investigate the influence of the biophysical properties of perfluorocarbons (PFD, FC75, and PFOB) and a natural porcine surfactant, Curosurf®; on aerosolization and to assess the suitability of three intratracheal inhalation catheters (IC) with different air flow rates (IC-1.23, IC-1.1, IC-1.4) coupled to a jet nebulizer, for aerosol delivery of these compounds. With IC-1.23 significantly higher aerosol production rates were achieved (p MMAD) ranged between 0.77 μm (PFD) and 8.29 μm (Curosurf®) with IC-1.1, whereas higher MMAD values, of between 4.84 μm (FC75) and 13.42 μm (PFOB), were observed with IC-1.23. Regardless of the catheter used during aerosolization, the perfluorocarbon with the highest kinematic viscosity showed the lowest aerosolization and emission rates and vice versa, which reveals the substantial contribution of this parameter that should accordingly be considered in the design of perfluorocarbon aerosol drug delivery systems. Jet aerosolization of perfluorocarbons or surfactant with the intratracheal inhalation catheters seems to be a suitable method for treating experimental respiratory distress syndrome, because it delivers relatively high doses of perfluorocarbons and surfactant to the lungs in a respirable size droplets.

  12. Droplet Vaporization in a Supercritical Microgravity Environment (United States)

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


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

  13. Utilization of diagnostic ultrasound and intravenous lipid-encapsulated perfluorocarbons in non-invasive targeted cardiovascular therapeutics. (United States)

    Porter, Thomas R; Choudhury, Songita A; Xie, Feng


    Diagnostic ultrasound (DUS) pressures have the ability to induce inertial cavitation (IC) of systemically administered microbubbles; this bioeffect has many diagnostic and therapeutic implications in cardiovascular care. Diagnostically, commercially available lipid-encapsulated perfluorocarbons (LEP) can be utilized to improve endocardial and vascular border delineation as well as assess myocardial perfusion. Therapeutically, the liquid jets induced by IC can alter endothelial function and dissolve thrombi within the immediate vicinity of the cavitating microbubbles. The cavitating LEP can also result in the localized release of any bound therapeutic substance at the site of insonation. DUS-induced IC has been tested in pre-clinical studies to determine what effect it has on acute vascular and microvascular thrombosis as well as nitric oxide (NO) release. These pre-clinical studies have consistently shown that DUS-induced IC of LEP is effective in restoring coronary vascular and microvascular flow in acute ST segment elevation myocardial infarction (STEMI), with microvascular flow improving even if upstream large vessel flow has not been achieved. The initial clinical trials examining the efficacy of short pulse duration DUS high mechanical index impulses in patients with STEMI are underway, and preliminary studies have suggested that earlier epicardial vessel recanalization can be achieved prior to arriving in the cardiac catheterization laboratory. DUS high mechanical index impulses have also been effective in pre-clinical studies for targeting DNA delivery that has restored islet cell function in type I diabetes and restored vascular flow in the extremities downstream from a peripheral vascular occlusion. Improvements in this technique will come from three dimensional arrays for therapeutic applications, more automated delivery techniques that can be applied in the field, and use of submicron-sized acoustically activated LEP droplets that may better permeate the

  14. Contribution of low vapor pressure-volatile organic compounds (LVP-VOCs) from consumer products to ozone formation in urban atmospheres (United States)

    Shin, Hyeong-Moo; McKone, Thomas E.; Bennett, Deborah H.


    Because recent laboratory testing indicates that some low vapor pressure-volatile organic compounds (LVP-VOC) solvents readily evaporate at ambient conditions, LVP-VOCs used in some consumer product formulations may contribute to ozone formation. The goal of this study is to determine the fraction of LVP-VOCs available for ozone formation from the use of consumer products for two hypothetical emissions. This study calculates and compares the fraction of consumed product available for ozone formation as a result of (a) volatilization to air during use and (b) down-the-drain disposal. The study also investigates the impact of different modes of releases on the overall fraction available in ambient air for ozone formation. For the portion of the LVP-VOCs volatilized to air during use, we applied a multi-compartment mass-balance model to track the fate of emitted LVP-VOCs in a multimedia urban environment. For the portion of the LVP-VOCs disposed down the drain, we used a wastewater treatment plant (WWTP) fate model to predict the emission rates of LVP-VOCs to ambient air at WWTPs or at the discharge zone of the facilities and then used these results as emissions in the multimedia urban environment model. In a WWTP, the LVP-VOCs selected in this study are primarily either biodegraded or removed via sorption to sludge depending on the magnitude of the biodegradation half-life and the octanol-water partition coefficient. Less than 0.2% of the LVP-VOCs disposed down the drain are available for ozone formation. In contrast, when the LVP-VOC in a consumer product is volatilized from the surface to which it has been applied, greater than 90% is available for photochemical reactions either at the source location or in the downwind areas. Comparing results from these two modes of releases allows us to understand the importance of determining the fraction of LVP-VOCs volatilized versus disposed down the drain when the product is used by consumers. The results from this study

  15. C and Si delta doping in Ge by CH{sub 3}SiH{sub 3} using reduced pressure chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Yuji, E-mail: [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Ueno, Naofumi; Sakuraba, Masao [Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1, Katahira, Aoba-Ku, Sendai 980-8577 (Japan); Murota, Junichi [Micro System Integration Center, Tohoku University, 519-1176, Aramaki aza Aoba, Aoba-ku, Sendai 980-0845 (Japan); Mai, Andreas [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Tillack, Bernd [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Technische Universität Berlin, HFT4, Einsteinufer 25, 10587 Berlin (Germany)


    C and Si delta doping in Ge are investigated using a reduced pressure chemical vapor deposition system to establish atomic-order controlled processes. CH{sub 3}SiH{sub 3} is exposed at 250 °C to 500 °C to a Ge on Si (100) substrate using H{sub 2} or N{sub 2} carrier gas followed by a Ge cap layer deposition. At 350 °C, C and Si are uniformly adsorbed on the Ge surface and the incorporated C and Si form steep delta profiles below detection limit of SIMS measurement. By using N{sub 2} as carrier gas, the incorporated C and Si doses in Ge are saturated at one mono-layer below 350 °C. At this temperature range, the incorporated C and Si doses are nearly the same, indicating CH{sub 3}SiH{sub 3} is adsorbed on the Ge surface without decomposing the C−Si bond. On the other hand, by using H{sub 2} as carrier gas, lower incorporated C is observed in comparison to Si. CH{sub 3}SiH{sub 3} injected with H{sub 2} carrier gas is adsorbed on Ge without decomposing the C−Si bond and the adsorbed C is reduced by dissociation of the C−Si bond during temperature ramp up to 550 °C. The adsorbed C is maintained on the Ge surface in N{sub 2} at 550 °C. - Highlights: • C and Si delta doping in Ge is investigated using RPCVD system by CH{sub 3}SiH{sub 3} exposure. • Atomically flat C and Si delta layers are fabricated at 350 °C. • Incorporated C and Si doses are saturated at one mono-layer below 350 °C. • CH{sub 3}SiH{sub 3} adsorption occurred without decomposing C−Si bond. • Adsorbed C is desorbed due to dissociation by hydrogen during postannealing at 550 °C.

  16. Dependence of O2 and Ar2 flow rates on the physical properties of ATO thin films deposited by atmospheric pressure chemical vapor deposition (APCVD) (United States)

    Fadavieslam, M. R.; Sadra, S.


    Antimony-doped tin oxide SnO2:Sb thin films were fabricated through atmospheric pressure chemical vapor deposition at T = 350 °C on soda lime glass substrates. After preparing the thin films, the effects of oxygen and argon flow rates on the structural, optical, and electrical properties were investigated. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy, atomic force microscopy, optical absorption (UV-Vis), and electrical resistance measurements using the two-point probe technique and the Hall effect. The results showed that the films contained uniform polycrystalline structures. Accordingly, the structural, morphological, optical, and electrical properties of the samples indicated the following effects: (a) Increasing the oxygen flow rate from 60 to 160 cc/min decreased the intensity of XRD peaks, the average roughness from 48.5 to 47.9 nm, the average transmission from 44 to 40 (in the visible region), the optical band gap from 3.74 to 3.66 eV, and the carrier mobility from 239.52 to 21.08 cm2/V.S; moreover, it increased the average grain size from 74 to 79 nm, the thickness from 320 to 560 nm, the specific resistance from 3.38 × 10-2 to 14.9 × 10-2 Ω cm, the carrier concentration from 7.72 × 1017 to 1.99 × 1018 cm-3, and the Seebeck coefficient from 47.2 to 57.85 μVk-1 (at 400 K). (b) Increasing the argon flow rate of 40 cc/min to 120 cc/min decreased the intensity of XRD peaks, the average size of grains from 88 nm to 61 nm, the optical band gap from 3.66 to 2.73 eV, the carrier concentration from 1.99 × 1018 to 1.73 × 1017 cm-3, and the Seebeck coefficient from 57.85 to 36.59 μVk-1 (at 400 k); moreover, this increased the average roughness from 47.9 to 50.8 nm, the average transmission from 40 to 64 (in the visible region), thickness from 560 to 620 nm, specific resistance from 14.9 × 10-2 to 39.87 × 10-2 Ω cm, and carrier mobility from 21.08 to 90.61 μv/vs. (c) All thin films had degenerate n

  17. Vapor Detector (United States)

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


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

  18. Vapor-liquid equilibria of trace isobutyraldehyde, ethyl acetate and isoamyl acetate in aqueous ethanol solution under reduced pressure; Ethanol suiyoekichu no biryo no isobutyraldehyde, sakusan ethyl, sakusan isoamyl no gen`atsu kieki heiko

    Energy Technology Data Exchange (ETDEWEB)

    Ikari, A.; Hatate, Y.; Aiko, R. [Kagoshima University, Kagoshima (Japan)


    Vapor-liquid equilibria of aqueous ethanol solutions containing a minute amount of acetaldehyde, isobutyraldehyde, ethyl acetate and isoamyl acetate were measured by use of an Othmer-type still at 12.7, 25.3 and 101.3 kPa. The equilibrium ratio curves of the minor components (isobutyraldehyde, ethyl acetate and isoamyl acetate) at each pressure are presented by a function of the concentration of ethanol. However, the equilibrium ratio curves of the minor component (acetaldehyde) could not be obtained, because the data is slightly scatted. 5 refs., 3 figs., 2 tabs.

  19. Simulating nectarine tree transpiration and dynamic water storage from responses of leaf conductance to light and sap flow to stem water potential and vapor pressure deficit. (United States)

    Paudel, Indira; Naor, Amos; Gal, Yoni; Cohen, Shabtai


    For isohydric trees mid-day water uptake is stable and depends on soil water status, reflected in pre-dawn leaf water potential (Ψpd) and mid-day stem water potential (Ψmd), tree hydraulic conductance and a more-or-less constant leaf water potential (Ψl) for much of the day, maintained by the stomata. Stabilization of Ψl can be represented by a linear relationship between canopy resistance (Rc) and vapor pressure deficit (D), and the slope (BD) is proportional to the steady-state water uptake. By analyzing sap flow (SF), meteorological and Ψmd measurements during a series of wetting and drying (D/W) cycles in a nectarine orchard, we found that for the range of Ψmd relevant for irrigated orchards the slope of the relationship of Rc to D, BD is a linear function of Ψmd. Rc was simulated using the above relationships, and its changes in the morning and evening were simulated using a rectangular hyperbolic relationship between leaf conductance and photosynthetic irradiance, fitted to leaf-level measurements. The latter was integrated with one-leaf, two-leaf and integrative radiation models, and the latter gave the best results. Simulated Rc was used in the Penman-Monteith equation to simulate tree transpiration, which was validated by comparing with SF from a separate data set. The model gave accurate estimates of diurnal and daily total tree transpiration for the range of Ψmds used in regular and deficit irrigation. Diurnal changes in tree water content were determined from the difference between simulated transpiration and measured SF. Changes in water content caused a time lag of 90-105 min between transpiration and SF for Ψmd between -0.8 and -1.55 MPa, and water depletion reached 3 l h(-1) before noon. Estimated mean diurnal changes in water content were 5.5 l day(-1) tree(-1) at Ψmd of -0.9 MPa and increased to 12.5 l day(-1) tree(-1) at -1.45 MPa, equivalent to 6.5 and 16.5% of daily tree water use, respectively. Sixteen percent

  20. Comparative analysis of high pressure sodium vapor lamps and mercury vapor lamp with the solid state (LED) in the public lighting systems; Analise comparativa das lampadas de vapor de sodio a alta pressao e de vapor de mercurio com a lampada a estado solido (LED) em sistemas de iluminacao publica

    Energy Technology Data Exchange (ETDEWEB)

    Damato, J.C.; Bueno, J.E.; Astorga, O.A.M. [Universidade Estadual Paulista (LESIP/UNESP), Guaratingueta, SP (Brazil). Lab. de Eficiencia Energetica em Sistemas de Iluminacao Publica; Ricciulli, D.L.S. [Universidade Estadual Paulista (DEE/UNESP), Guaratingueta, SP (Brazil). Dept. de Engenharia Eletrica


    The necessity of energy conservation in Brazilian electric sector, with the intention to diminish the resources of generation investments, has going to use of electric energy conservation programs, being most important PROCEL - a national program of electric conservation energy by ELETROBRAS, and inside this, a national program for public illumination and efficient traffic signaling - named 'Reluz'. This program looks for a more efficient implantation of public lighting systems, that requires the use of lamp technologies that present a greater value in a relation between lumen/watt relation and then beyond providing economy, due to low consumption of electric energy. Besides technologies that are appearing, the inclusion of LED lamps, which offers a great application potential, comes blunting as improvement alternative, being that the next public illumination parks will be able count on these lamps associates to the high-pressure sodium lamps and other types currently used. (author)

  1. Perfluorocarbon emulsions radiosensitise brain tumors in carbogen breathing mice with orthotopic GL261 gliomas (United States)

    Feldman, Lisa A.; Fabre, Marie-Sophie; Grasso, Carole; Reid, Dana; Broaddus, William C.; Lanza, Gregory M.; Spiess, Bruce D.; Garbow, Joel R.; McConnell, Melanie J.


    Background Tumour hypoxia limits the effectiveness of radiation therapy. Delivering normobaric or hyperbaric oxygen therapy elevates pO2 in both tumour and normal brain tissue. However, pO2 levels return to baseline within 15 minutes of stopping therapy. Aim To investigate the effect of perfluorocarbon (PFC) emulsions on hypoxia in subcutaneous and intracranial mouse gliomas and their radiosensitising effect in orthotopic gliomas in mice breathing carbogen (95%O2 and 5%CO2). Results PFC emulsions completely abrogated hypoxia in both subcutaneous and intracranial GL261 models and conferred a significant survival advantage orthotopically (Mantel Cox: p = 0.048) in carbogen breathing mice injected intravenously (IV) with PFC emulsions before radiation versus mice receiving radiation alone. Carbogen alone decreased hypoxia levels substantially and conferred a smaller but not statistically significant survival advantage over and above radiation alone. Conclusion IV injections of PFC emulsions followed by 1h carbogen breathing, radiosensitises GL261 intracranial tumors. PMID:28873460

  2. Modified headspace solid-phase microextraction for the determination of quantitative relationships between components of mixtures consisting of alcohols, esters, and ethers - impact of the vapor pressure difference of the compounds. (United States)

    Dawidowicz, Andrzej Lech; Szewczyk, Joanna; Dybowski, Michal P


    The quantitative relationship between analytes established by the headspace solid-phase microextraction procedure for multicomponent mixtures depends not only on the character and strength of interactions of individual components with solid-phase microextraction fiber but also on their vapor pressure in the applied headspace solid-phase microextraction system. This study proves that vapor pressure is of minor importance when the sample is dissolved/suspended in a low-volatility liquid of the same physicochemical character as that of the used solid phase microextraction fiber coating. It is demonstrated for mixtures of alcohols, esters, ethers and their selected representatives by applying a headspace solid-phase microextraction system composed of Carbowax fiber and sample solutions in polyethyleneglycol. The observed differences in quantitative relations between components of the examined mixtures established by their direct analysis and by modified headspace solid-phase microextraction are insignificant (Fexp  headspace solid phase microextraction system due to low components concentration in polyethyleneglycol suspensions (Raoult's law) and due to strong specific interactions of analyte molecules with polyethyleneglycol molecules. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Validation of Hiriart equation to compute steam production by the lip pressure method; Validacion de la ecuacion de Hiriart para calculo de gasto de vapor por el metodo de presion de labio

    Energy Technology Data Exchange (ETDEWEB)

    Flores Armenta, Magaly [Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)


    Mainly in new geothermal wells, it is necessary to evaluate the production in a very fast, simple and not expensive way, to know the convenience to install surface equipment, such as silencers and separators, to drive the steam to the commercial gathering system. In practice, one of the most known methods is the lip pressure one, which requires a simple set of installations. The objective of this paper is to validate the steam flow rate calculated by the lip pressure method, with respect to the ASME method. The ASME method is known for its accuracy, and is done by measuring the steam and liquid after a high pressure separator, by an orifice plate of known diameter and a triangular weir. Results of the validation show up the feasibility of application of the lip pressure method by using a simple adjustment equation. Percentage of mistake results less than 1%, without any notable influence of the production enthalpy. That equation to be applied in a general case, is as follows: Q{nu} =(20642)(F*P*D{sup 2}/{radical}h-2000). For the particular case of the Los Azufres geothermal field, the equation is: Q{nu}= 810*P*D{sup 2} [Espanol] En los pozos geotermicos, principalmente en los nuevos, es necesario evaluar su produccion de manera rapida, sencilla y economica, para determinar la conveniencia de instalar equipo superficial, como separadores, silenciadores, etc., que permita la integracion del vapor al sistema comercial de generacion electrica. Para fines practicos uno de los metodos mas conocidos es el de presion de labio, que solo requiere un arreglo sencillo de instalaciones superficiales. En este documento se validan y ajustan los calculos de produccion de vapor por ese metodo de presion de labio, con respecto a las mediciones exactas efectuadas con el metodo ASME. Este ultimo es reconocido internacionalmente por su precision, y se lleva a cabo separando la mezcla obtenida en superficie en un recipiente a presion para medir el vapor a traves de una placa de orificio

  4. Vaporization Would Cool Primary Battery (United States)

    Bhandari, Pradeep; Miyake, Robert N.


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

  5. Water Vapor Effects on Silica-Forming Ceramics (United States)

    Opila, E. J.; Greenbauer-Seng, L. (Technical Monitor)


    Silica-forming ceramics such as SiC and Si3N4 are proposed for applications in combustion environments. These environments contain water vapor as a product of combustion. Oxidation of silica-formers is more rapid in water vapor than in oxygen. Parabolic oxidation rates increase with the water vapor partial pressure with a power law exponent value close to one. Molecular water vapor is therefore the mobile species in silica. Rapid oxidation rates and large amounts of gases generated during the oxidation reaction in high water vapor pressures may result in bubble formation in the silica and nonprotective scale formation. It is also shown that silica reacts with water vapor to form Si(OH)4(g). Silica volatility has been modeled using a laminar flow boundary layer controlled reaction equation. Silica volatility depends on the partial pressure of water vapor, the total pressure, and the gas velocity. Simultaneous oxidation and volatilization reactions have been modeled with paralinear kinetics.

  6. Accurate and stable equal-pressure measurements of water vapor transmission rate reaching the 10-6 g m-2 day-1 range (United States)

    Nakano, Yoichiro; Yanase, Takashi; Nagahama, Taro; Yoshida, Hajime; Shimada, Toshihiro


    The water vapor transmission rate (WVTR) of a gas barrier coating is a critically important parameter for flexible organic device packaging, but its accurate measurement without mechanical stress to ultrathin films has been a significant challenge in instrumental analysis. At the current stage, no reliable results have been reported in the range of 10-6 g m-2 day-1 that is required for organic light emitting diodes (OLEDs). In this article, we describe a solution for this difficult, but important measurement, involving enhanced sensitivity by a cold trap, stabilized temperature system, pumped sealing and calibration by a standard conductance element.

  7. Optical droplet vaporization of nanoparticle-loaded stimuli-responsive microbubbles

    Energy Technology Data Exchange (ETDEWEB)

    Si, Ting [Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027 (China); Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Li, Guangbin; Luo, Xisheng [Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027 (China); Wu, Qiang; Zhu, Zhiqiang [Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230027 (China); Xu, Ronald X., E-mail: [Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230027 (China)


    A capillary co-flow focusing process is developed to generate stimuli-responsive microbubbles (SRMs) that comprise perfluorocarbon (PFC) suspension of silver nanoparticles (SNPs) in a lipid shell. Upon continuous laser irradiation at around their surface plasmon resonance band, the SNPs effectively absorb electromagnetic energy, induce heat accumulation in SRMs, trigger PFC vaporization, and eventually lead to thermal expansion and fragmentation of the SRMs. This optical droplet vaporization (ODV) process is further simulated by a theoretical model that combines heat generation of SNPs, phase change of PFC, and thermal expansion of SRMs. The model is validated by benchtop experiments, where the ODV process is monitored by microscopic imaging. The effects of primary process parameters on behaviors of ODV are predicted by the theoretical model, indicating the technical feasibility for process control and optimization in future drug delivery applications.

  8. Hydrophobic-induced Surface Reorganization: Molecular Dynamics Simulations of Water Nanodroplet on Perfluorocarbon Self-Assembled Monolayers


    Park, Sung Hyun; Carignano, Marcelo A.; Nap, Rikkert J.; Szleifer, Igal


    We carried out molecular dynamics simulations of water droplets on self-assembled monolayers of perfluorocarbon molecules. The interactions between the water droplet and the hydrophobic fluorocarbon surface were studied by systematically changing the molecular surface coverage and the mobility of the tethered head groups of the surface chain molecules. The microscopic contact angles were determined for different fluorocarbon surface densities. The contact angle at a nanometer length scale doe...

  9. New mechanisms for non-porative ultrasound stimulation of cargo delivery to cell cytosol with targeted perfluorocarbon nanoparticles


    Soman, NR; Marsh, JN; Lanza, GM; Wickline, SA


    The cell membrane constitutes a major barrier for non-endocytotic intracellular delivery of therapeutic molecules from drug delivery vehicles. Existing approaches to breaching the cell membrane include cavitational ultrasound (with microbubbles), electroporation and cell-penetrating peptides. We report the use of diagnostic ultrasound for intracellular delivery of therapeutic bulky cargo with the use of molecularly targeted liquid perfluorocarbon (PFC) nanoparticles. To demonstrate the concep...

  10. Quantitative absorption spectroscopy of residual water vapor in high-purity gases: pressure broadening of the 1.39253-microm H2O transition by N2, HCl, HBr, Cl2, and O2. (United States)

    Vorsa, Vasil; Dheandhanoo, Seksan; Ketkar, Suhas N; Hodges, Joseph T


    We determined the respective pressure-broadening coefficients of HCl, HBr, Cl2, and O2 (expressed relative to that of the reference gas N2) for the (v1,v2,v3)J(Ka,Kc) = (0,0,0)3(0,3) --> (1,0,1)2(0,2) rovibrational transition of H2 16O that occurs at 1.39253 microm. The experiment used a continuous-wave cavity ring-down spectroscopy analyzer to measure the peak absorption losses as a function of added moisture concentration. The measured pressure-broadening coefficients for HCl, HBr, Cl2, and O2 are, respectively, 2.76, 2.48, 1.39, and 0.49 times that of the N2 pressure-broadening coefficient, and detection limits for water vapor range from 0.22 nmol mol(-1) for O2 matrix gas to 2.3 nmol mol(-1) for HBr matrix gas. The degradation of the detection limit (relative to the N2 matrix gas) is ascribed to a pressure-broadening-induced reduction in peak absorption cross section and to elevated background loss from the matrix gas.

  11. Atomic vapor density monitor

    Energy Technology Data Exchange (ETDEWEB)

    Sewall, N.; Harris, W.; Beeler, R.; Wooldridge, J.; Chen, H.L.


    This report presents information on the Atomic Vapor Density Monitor (AVDM) system that measures the density of a vapor by measuring the absorption of light from a swept-wavelength laser that passes through an atomic vapor stream.

  12. Petroleum Vapor Intrusion (United States)

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

  13. Vapor condensation behind the shock wave in vapor-liquid two-phase media (United States)

    Syoji, Chiharu; Oshiro, Naoto

    Laser extinction, schlieren photography, and in situ pressure measurements are used to characterize vapor condensation behind a shock wave in a diaphragm shock tube with a low-pressure chamber filled with ethanol, water, or freon-11 vapor. The experimental setup is briefly described, and the results are presented graphically and discussed in detail. Condensation, lasting a few hundred microsec before reevaporation sets in, is found to decrease the intensity of the shock front and lower the pressure behind it.

  14. A Lithium Vapor Box Divertor Similarity Experiment (United States)

    Cohen, Robert A.; Emdee, Eric D.; Goldston, Robert J.; Jaworski, Michael A.; Schwartz, Jacob A.


    A lithium vapor box divertor offers an alternate means of managing the extreme power density of divertor plasmas by leveraging gaseous lithium to volumetrically extract power. The vapor box divertor is a baffled slot with liquid lithium coated walls held at temperatures which increase toward the divertor floor. The resulting vapor pressure differential drives gaseous lithium from hotter chambers into cooler ones, where the lithium condenses and returns. A similarity experiment was devised to investigate the advantages offered by a vapor box divertor design. We discuss the design, construction, and early findings of the vapor box divertor experiment including vapor can construction, power transfer calculations, joint integrity tests, and thermocouple data logging. Heat redistribution of an incident plasma-based heat flux from a typical linear plasma device is also presented. This work supported by DOE Contract No. DE-AC02-09CH11466 and The Princeton Environmental Institute.

  15. 40 CFR 52.787 - Gasoline transfer vapor control. (United States)


    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Gasoline transfer vapor control. 52.787... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Indiana § 52.787 Gasoline transfer vapor control. (a) Gasoline means any petroleum distillate having a Reid vapor pressure of 4 pounds or greater...

  16. 40 CFR 52.255 - Gasoline transfer vapor control. (United States)


    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Gasoline transfer vapor control. 52.255... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.255 Gasoline transfer vapor control. (a) “Gasoline” means any petroleum distillate having a Reid vapor pressure of 4 pounds or greater...

  17. Conductimetry and impedance spectroscopy study of low pressure metal organic chemical vapor deposition TiN xO y films as a function of the growth temperature: a percolation approach (United States)

    Fabreguette, F.; Maglione, M.; Imhoff, L.; Domenichini, B.; Marco de Lucas, M. C.; Sibillot, P.; Bourgeois, S.; Sacilotti, M.


    Titanium oxinitride thin films have been grown by low pressure metal organic chemical vapor deposition (LP-MOCVD) using titanium isopropoxide, Ti(OCH(CH 3) 2) 4 (TIP) and NH 3 precursors in a growth temperature range from 450 to 750°C on sapphire substrates. The electrical behaviour of these films was studied between 400 and 173 K, revealing three different behaviours, ranking from a hopping conductivity (450-500°C) to a conducting one (700-750°C), with a dual behaviour for the intermediate growth temperatures. Moreover, at room temperature, both conductimetry and impedance spectroscopy highlighted a percolation behaviour, interpreted in terms of continuum percolation. The effective media theory equations led to the usual percolation parameters ( s, t, Φc) and the difference between the values thus obtained and the expected ones was explained in terms of anisotropic percolation occurring in the columnar film structure.

  18. Effects of Emulsion Composition on Pulmonary Tobramycin Delivery During Antibacterial Perfluorocarbon Ventilation. (United States)

    Orizondo, Ryan A; Fabiilli, Mario L; Morales, Marissa A; Cook, Keith E


    The effectiveness of inhaled aerosolized antibiotics is limited by poor ventilation of infected airways. Pulmonary delivery of antibiotics emulsified within liquid perfluorocarbon [antibacterial perfluorocarbon ventilation (APV)] may solve this problem through better airway penetration and improved spatial uniformity. However, little work has been done to explore emulsion formulation and the corresponding effects on drug delivery during APV. This study investigated the effects of emulsion formulation on emulsion stability and the pharmacokinetics of antibiotic delivery via APV. Gravity-driven phase separation was examined in vitro by measuring emulsion tobramycin concentrations at varying heights within a column of emulsion over 4 hours for varying values of fluorosurfactant concentration (Cfs = 5-48 mg/mL H2O). Serum and pulmonary tobramycin concentrations in rats were then evaluated following pulmonary tobramycin delivery via aerosol or APV utilizing sufficiently stable emulsions of varying aqueous volume percentage (Vaq = 1%-5%), aqueous tobramycin concentration (Ct = 20-100 mg/mL), and Cfs (15 and 48 mg/mL H2O). In vitro assessment showed sufficient spatial and temporal uniformity of tobramycin dispersion within emulsion for Cfs ≥15 mg/mL H2O, while lower Cfs values showed insufficient emulsification even immediately following preparation. APV with stable emulsion formulations resulted in 5-22 times greater pulmonary tobramycin concentrations at 4 hours post-delivery relative to aerosolized delivery. Concentrations increased with emulsion formulations utilizing increased Vaq (with decreased Ct) and, to a lesser extent, increased Cfs. The emulsion stability necessary for effective delivery is retained at Cfs values as low as 15 mg/mL H2O. Additionally, the pulmonary retention of antibiotic delivered via APV is significantly greater than that of aerosolized delivery and can be most effectively increased by increasing Vaq and decreasing

  19. Modified Perfluorocarbon Tracer Method for Measuring Effective Multizone Air Exchange Rates

    Directory of Open Access Journals (Sweden)

    Masashi Gamo


    Full Text Available A modified procedure was developed for the measurement of the effective air exchange rate, which represents the relationship between the pollutants emitted from indoor sources and the residents’ level of exposure, by placing the dosers of tracer gas at locations that resemble indoor emission sources. To measure the 24-h-average effective air exchange rates in future surveys based on this procedure, a low-cost, easy-to-use perfluorocarbon tracer (PFT doser with a stable dosing rate was developed by using double glass vials, a needle, a polyethylene-sintered filter, and a diffusion tube. Carbon molecular sieve cartridges and carbon disulfide (CS2 were used for passive sampling and extraction of the tracer gas, respectively. Recovery efficiencies, sampling rates, and lower detection limits for 24-h sampling of hexafluorobenzene, octafluorotoluene, and perfluoroallylbenzene were 40% ± 3%, 72% ± 5%, and 84% ± 6%; 10.5 ± 1.1, 14.4 ± 1.4, and 12.2 ± 0.49 mL min−1; and 0.20, 0.17, and 0.26 μg m–3, respectively.

  20. Perfluorocarbon thin films and polymer brushes on stainless steel 316L for control of interfacial properties (United States)

    Kruszewski, Kristen M.


    Perfluorocarbon thin films and polymer brushes were formed on stainless steel 316L (SS316L) to control the surface properties of the metal oxide. Substrates modified with the films were characterized using diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), contact angle analysis, atomic force microscopy (AFM), and cyclic voltammetry (CV). Perfluorooctadecanoic acid (PFOA) was used to form thin films by self-assembly on the surface of SS316L. Polypentafluorostyrene (PFS) polymer brushes were formed by surface initiated polymerization using SAMs of 16-phosphonohexadecanoic acid (COOH-PA) as the base. PFOA and PFS were effective in significantly reducing the surface energy and thus the interfacial wetting properties of SS316L. The SS316L control exhibited a surface energy of 38 mN/m compared to PFOA and PFS modifications, which had surface energies of 22 and 24 mN/m, respectively. PFOA thin films were more effective in reducing the surface energy of the SS316L compared to PFS polymer brushes. This is attributed to the ordered PFOA film presenting aligned CF3 terminal groups. However, PFS polymer brushes were more effective in providing corrosion protection. These low energy surfaces could be used to provide a hydrophobic barrier that inhibits corrosion of the SS316L metal oxide surface. PMID:21631123

  1. Recent Advances in 19Fluorine Magnetic Resonance Imaging with Perfluorocarbon Emulsions

    Directory of Open Access Journals (Sweden)

    Anne H. Schmieder


    Full Text Available The research roots of 19fluorine (19F magnetic resonance imaging (MRI date back over 35 years. Over that time span, 1H imaging flourished and was adopted worldwide with an endless array of applications and imaging approaches, making magnetic resonance an indispensable pillar of biomedical diagnostic imaging. For many years during this timeframe, 19F imaging research continued at a slow pace as the various attributes of the technique were explored. However, over the last decade and particularly the last several years, the pace and clinical relevance of 19F imaging has exploded. In part, this is due to advances in MRI instrumentation, 19F/1H coil designs, and ultrafast pulse sequence development for both preclinical and clinical scanners. These achievements, coupled with interest in the molecular imaging of anatomy and physiology, and combined with a cadre of innovative agents, have brought the concept of 19F into early clinical evaluation. In this review, we attempt to provide a slice of this rich history of research and development, with a particular focus on liquid perfluorocarbon compound-based agents.

  2. A Really Good Hammer: Quantification of Mass Transfer Using Perfluorocarbon Tracers (475th Brookhaven Lecture)

    Energy Technology Data Exchange (ETDEWEB)

    Watson, Tom [BNL Environmental Sciences, Tracer Technology Group


    Brookhaven Lab’s perfluorocarbon tracer (PFT) technology can be viewed as a hammer looking for nails. But, according to Tom Watson, leader of the Lab’s Tracer Technology Group in the Environmental Research and Technology Division (ERTD), “It’s a really good hammer!” The colorless, odorless and safe gases have a number of research uses, from modeling how airborne contaminants might move through urban canyons to help first responders plan their response to potential terrorist attacks and accidents to locating leaks in underground gas pipes. Their extremely low background level — detectable at one part per quadrillion — allows their transport to be easily tracked. Lab researchers used PFTs during the 2005 Urban Dispersion Program field studies in New York City, gathering data to help improve models of how a gas or chemical release might move around Manhattan’s tall buildings and canyons. Closer to home, scientists also used PFTs to make ventilation measurements in Bldg. 400 on the Lab site to provide data to test air flow models used in determining the effects of passive and active air exchange on the levels of indoor and outdoor air pollution, and to determine the effects of an accidental or intentional release of hazardous substances in or around buildings.

  3. In vitro alteration of hematological parameters and blood viscosity by the perfluorocarbon: Oxycyte. (United States)

    Arnaud, Françoise; Sanders, Katherine; Sieckmann, Donna; Moon-Massat, Paula


    While perfluorocarbons (PFCs) may be useful in some clinical situations, previous studies have shown that interferences with chemistry analytes can occur with blood samples containing PFCs. This in vitro study focused on how the PFC Oxycyte may affect hematology measurements in blood samples. Swine blood diluted with Oxycyte or saline (Controls) were analyzed for Hemoglobin (Hb), Mean Corpuscular Volume (MCV),Hematocrit (Hct) and Fluorocrit (Fct) using a HemaVet, ABL-735 (ABL), or microhematocrit. Ancillary tests (blood viscosity, electrolytes, cell counts, and red blood cell morphology) were performed secondarily. Increasing Oxycyte resulted in increases in MCV, Hct, and visible cell shape change and morphology vs. Effects correlated with lower sodium in Oxycyte samples vs. With increasing Oxycyte, Hb became higher than Controls or became unpredictable depending on the instrument (HemaVet or ABL, respectively). Fct was smaller than predicted and likely represented the heaviest components of Oxycyte. At ≥50 % Oxycyte, RBC hemolysis rendered further measurements impractical. Viscosity first increased then decreased with increasing Oxycyte, peaking at ~40 % Oxycyte. Hct, MCV, Hb, and RBC morphology may be affected by Oxycyte. These observations correlated with lower sodium and increasing Oxycyte, causing hemolysis at high Oxycyte concentrations. These changes were due to alterations in the blood samples in vitro and this should be considered when interpreting hematology parameters from in vivo studies.

  4. Perfluorocarbons and Gilbert syndrome (phenotype) in the C8 Health Study Population

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Hongmin [Cancer Center, School of Public Health, West Virginia University, Morgantown, WV 265050-9190 (United States); Department of Epidemiology and Statistics, School of Public Health, Hebei United University, Hebei 063000 (China); Ducatman, Alan [Department of Occupational and Environmental Health, School of Public Health, West Virginia University (United States); Department of Medicine, School of Medicine, West Virginia University (United States); Clinical Translational Science Institute, West Virginia University (United States); Zhang, Jianjun [Department of Biostatistics, School Public Health, West Virginia University (United States)


    Background: Gilbert syndrome (GS) is an inherited defect of bilirubin conjugation, most commonly caused by a gene mutation for the enzyme UGT1A. GS is known to affect the metabolism and excretion of drugs and xenobiotics. Perfluorocarbon compounds (PFCs) are bio-persistent environmental contaminants that affect metabolic regulation. In this study, we examined the associations of GS phenotype and serum PFCs in the C8 Health Study Population. Materials and methods: Using 2005–2006 data from a large PFC-exposure population survey, we compared serum PFCs concentrations between GS and non GS clinical phenotypes, in a cross sectional design, adjusting for standard risk factors, including age, BMI, smoking status, socioeconomic status and gender. Results: Among 10 PFC compounds considered, only perfluorohexanoic acid (PFHxA) was seen at a significantly higher concentration in GS men and women. Conclusion: PFHxA exposure may be associated with GS. Our findings do not support increased exposure in GS for other PFCs. - Highlights: • Most serum PFCs are not associated with clinically evident Gilbert syndrome. • However, serum perfluorohexanoic acid is positively associated. • The investigation addresses the clinical presentation, not the genetic mutation.

  5. Cell Labeling for 19F MRI: New and Improved Approach to Perfluorocarbon Nanoemulsion Design (United States)

    Patel, Sravan K.; Williams, Jonathan; Janjic, Jelena M.


    This report describes novel perfluorocarbon (PFC) nanoemulsions designed to improve ex vivo cell labeling for 19F magnetic resonance imaging (MRI). 19F MRI is a powerful non-invasive technique for monitoring cells of the immune system in vivo, where cells are labeled ex vivo with PFC nanoemulsions in cell culture. The quality of 19F MRI is directly affected by the quality of ex vivo PFC cell labeling. When co-cultured with cells for longer periods of time, nanoemulsions tend to settle due to high specific weight of PFC oils (1.5–2.0 g/mL). This in turn can decrease efficacy of excess nanoemulsion removal and reliability of the cell labeling in vitro. To solve this problem, novel PFC nanoemulsions are reported which demonstrate lack of sedimentation and high stability under cell labeling conditions. They are monodisperse, have small droplet size (~130 nm) and low polydispersity (nanoemulsion droplet size and polydispersity. Detailed synthetic methodology and in vitro testing for these new PFC nanoemulsions is presented. PMID:25586263

  6. Cell Labeling for 19F MRI: New and Improved Approach to Perfluorocarbon Nanoemulsion Design

    Directory of Open Access Journals (Sweden)

    Jonathan Williams


    Full Text Available This report describes novel perfluorocarbon (PFC nanoemulsions designed to improve ex vivo cell labeling for 19F magnetic resonance imaging (MRI. 19F MRI is a powerful non-invasive technique for monitoring cells of the immune system in vivo, where cells are labeled ex vivo with PFC nanoemulsions in cell culture. The quality of 19F MRI is directly affected by the quality of ex vivo PFC cell labeling. When co-cultured with cells for longer periods of time, nanoemulsions tend to settle due to high specific weight of PFC oils (1.5–2.0 g/mL. This in turn can decrease efficacy of excess nanoemulsion removal and reliability of the cell labeling in vitro. To solve this problem, novel PFC nanoemulsions are reported which demonstrate lack of sedimentation and high stability under cell labeling conditions. They are monodisperse, have small droplet size (~130 nm and low polydispersity (<0.15, show a single peak in the 19F nuclear magnetic resonance spectrum at −71.4 ppm and possess high fluorine content. The droplet size and polydispersity remained unchanged after 160 days of follow up at three temperatures (4, 25 and 37 °C. Further, stressors such as elevated temperature in the presence of cells, and centrifugation, did not affect the nanoemulsion droplet size and polydispersity. Detailed synthetic methodology and in vitro testing for these new PFC nanoemulsions is presented.

  7. Addition of perfluorocarbons to alginate hydrogels significantly impacts molecular transport and fracture stress. (United States)

    White, Joseph C; Stoppel, Whitney L; Roberts, Susan C; Bhatia, Surita R


    Perfluorocarbons (PFCs) are used in biomaterial formulations to increase oxygen (O(2) ) tension and create a homogeneous O(2) environment in three-dimensional tissue constructs. It is unclear how PFCs affect mechanical and transport properties of the scaffold, which are critical for robustness, intracellular signaling, protein transport, and overall device efficacy. In this study, we investigate composite alginate hydrogels containing a perfluorooctyl bromide (PFOB) emulsion stabilized with Pluronic(®) F68 (F68). We demonstrate that PFC addition significantly affects biomaterial properties and performance. Solution and hydrogel mechanical properties and transport of representative hydrophilic (riboflavin), hydrophobic (methyl and ethyl paraben), and protein (bovine serum albumin, BSA) solutes were compared in alginate/F68 composite hydrogels with or without PFOB. Our results indicate that mechanical properties of the alginate/F68/PFOB hydrogels are not significantly affected under small strains, but a significant decrease fracture stress is observed. The effective diffusivity D(eff) of hydrophobic small molecules decreases with PFOB emulsion addition, yet the D(eff) of hydrophilic small molecules remained unaffected. For BSA, the D(eff) increased and the loading capacity decreased with PFOB emulsion addition. Thus, a trade-off between the desired increased O(2) supply provided by PFCs and the mechanical weakening and change in transport of cellular signals must be carefully considered in the design of biomaterials containing PFCs. Copyright © 2012 Wiley Periodicals, Inc.

  8. A demonstration experiment for studying the properties of saturated vapor (United States)

    Grebenev, Igor V.; Lebedeva, Olga V.; Polushkina, Svetlana V.


    The paper proposes an important demonstration experiment that can be used at secondary schools in physics. The described experiment helps students learn the main concepts of the topic ‘saturated vapor’, namely, evaporation, condensation, dynamic equilibrium, saturation vapor, partial pressure, and the dependence of saturated vapor pressure on temperature.

  9. Supercritical microgravity droplet vaporization (United States)

    Hartfield, J.; Curtis, E.; Farrell, P.


    Supercritical droplet vaporization is an important issue in many combustion systems, such as liquid fueled rockets and compression-ignition (diesel) engines. In order to study the details of droplet behavior at these conditions, an experiment was designed to provide a gas phase environment which is above the critical pressure and critical temperature of a single liquid droplet. In general, the droplet begins as a cold droplet in the hot, high pressure environment. In order to eliminate disruptions to the droplet by convective motion in the gas, forced and natural convection gas motion are required to be small. Implementation of this requirement for forced convection is straightforward, while reduction of natural convection is achieved by reduction in the g-level for the experiment. The resulting experiment consists of a rig which can stably position a droplet without restraint in a high-pressure, high temperature gas field in microgravity. The microgravity field is currently achieved by dropping the device in the NASA Lewis 2.2 second drop tower. The performance of the experimental device and results to date are presented.

  10. Vapor-barrier Vacuum Isolation System (United States)

    Weinstein, Leonard M. (Inventor); Taminger, Karen M. (Inventor)


    A system includes a collimated beam source within a vacuum chamber, a condensable barrier gas, cooling material, a pump, and isolation chambers cooled by the cooling material to condense the barrier gas. Pressure levels of each isolation chamber are substantially greater than in the vacuum chamber. Coaxially-aligned orifices connect a working chamber, the isolation chambers, and the vacuum chamber. The pump evacuates uncondensed barrier gas. The barrier gas blocks entry of atmospheric vapor from the working chamber into the isolation chambers, and undergoes supersonic flow expansion upon entering each isolation chamber. A method includes connecting the isolation chambers to the vacuum chamber, directing vapor to a boundary with the working chamber, and supersonically expanding the vapor as it enters the isolation chambers via the orifices. The vapor condenses in each isolation chamber using the cooling material, and uncondensed vapor is pumped out of the isolation chambers via the pump.

  11. Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation (United States)

    Kopechek, Jonathan A.; Zhang, Peng; Burgess, Mark T.; Porter, Tyrone M.


    High-intensity focused ultrasound (HIFU) is used clinically to thermally ablate tumors. To enhance localized heating and improve thermal ablation in tumors, lipid-coated perfluorocarbon droplets have been developed which can be vaporized by HIFU. The vasculature in many tumors is abnormally leaky due to their rapid growth, and nanoparticles are able to penetrate the fenestrations and passively accumulate within tumors. Thus, controlling the size of the droplets can result in better accumulation within tumors. In this report, the preparation of stable droplets in a phase-shift nanoemulsion (PSNE) with a narrow size distribution is described. PSNE were synthesized by sonicating a lipid solution in the presence of liquid perfluorocarbon. A narrow size distribution was obtained by extruding the PSNE multiple times using filters with pore sizes of 100 or 200 nm. The size distribution was measured over a 7-day period using dynamic light scattering. Polyacrylamide hydrogels containing PSNE were prepared for in vitro experiments. PSNE droplets in the hydrogels were vaporized with ultrasound and the resulting bubbles enhanced localized heating. Vaporized PSNE enables more rapid heating and also reduces the ultrasound intensity needed for thermal ablation. Thus, PSNE is expected to enhance thermal ablation in tumors, potentially improving therapeutic outcomes of HIFU-mediated thermal ablation treatments. PMID:23007836

  12. Impact vaporization: Late time phenomena from experiments (United States)

    Schultz, P. H.; Gault, D. E.


    While simple airflow produced by the outward movement of the ejecta curtain can be scaled to large dimensions, the interaction between an impact-vaporized component and the ejecta curtain is more complicated. The goal of these experiments was to examine such interaction in a real system involving crater growth, ejection of material, two phased mixtures of gas and dust, and strong pressure gradients. The results will be complemented by theoretical studies at laboratory scales in order to separate the various parameters for planetary scale processes. These experiments prompt, however, the following conclusions that may have relevance at broader scales. First, under near vacuum or low atmospheric pressures, an expanding vapor cloud scours the surrounding surface in advance of arriving ejecta. Second, the effect of early-time vaporization is relatively unimportant at late-times. Third, the overpressure created within the crater cavity by significant vaporization results in increased cratering efficiency and larger aspect ratios.

  13. Recommended reference materials for realization of physicochemical properties pressure-volume-temperature relationships

    CERN Document Server

    Herington, E F G


    Recommended Reference Materials for Realization of Physicochemical Properties presents recommendations of reference materials for use in measurements involving physicochemical properties, namely, vapor pressure; liquid-vapor critical temperature and critical pressure; orthobaric volumes of liquid and vapor; pressure-volume-temperature properties of the unsaturated vapor or gas; and pressure-volume-temperature properties of the compressed liquid. This monograph focuses on reference materials for vapor pressures at temperatures up to 770 K, as well as critical temperatures and critical pressures

  14. Condensation of vapor bubble in subcooled pool (United States)

    Horiuchi, K.; Koiwa, Y.; Kaneko, T.; Ueno, I.


    We focus on condensation process of vapor bubble exposed to a pooled liquid of subcooled conditions. Two different geometries are employed in the present research; one is the evaporation on the heated surface, that is, subcooled pool boiling, and the other the injection of vapor into the subcooled pool. The test fluid is water, and all series of the experiments are conducted under the atmospheric pressure condition. The degree of subcooling is ranged from 10 to 40 K. Through the boiling experiment, unique phenomenon known as microbubble emission boiling (MEB) is introduced; this phenomenon realizes heat flux about 10 times higher than the critical heat flux. Condensation of the vapor bubble is the key phenomenon to supply ambient cold liquid to the heated surface. In order to understand the condensing process in the MEB, we prepare vapor in the vapor generator instead of the evaporation on the heated surface, and inject the vapor to expose the vapor bubble to the subcooled liquid. Special attention is paid to the dynamics of the vapor bubble detected by the high-speed video camera, and on the enhancement of the heat transfer due to the variation of interface area driven by the condensation.

  15. Vapor degreasing system (United States)

    du Fresne, Eugene R. (Inventor)


    A vapor degreasing method and apparatus wherein a second cooling coil is used to prevent escape of solvent or solvent vapor from a degreaser. Gaseous refrigerant from the second coil can be released to the freeboard space above the solvent vapor zone to provide a barrier layer.

  16. Water vapor adsorption on goethite. (United States)

    Song, Xiaowei; Boily, Jean-François


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

  17. Organo-Chlorinated Thin Films Deposited by Atmospheric Pressure Plasma-Enhanced Chemical Vapor Deposition for Adhesion Enhancement between Rubber and Zinc-Plated Steel Monofilaments. (United States)

    Vandenabeele, Cédric; Bulou, Simon; Maurau, Rémy; Siffer, Frederic; Belmonte, Thierry; Choquet, Patrick


    A continuous-flow plasma process working at atmospheric pressure is developed to enhance the adhesion between a rubber compound and a zinc-plated steel monofilament, with the long-term objective to find a potential alternative to the electrolytic brass plating process, which is currently used in tire industry. For this purpose, a highly efficient tubular dielectric barrier discharge reactor is built to allow the continuous treatment of "endless" cylindrical substrates. The best treatment conditions found regarding adhesion are Ar/O2 plasma pretreatment, followed by the deposition from dichloromethane of a 75 nm-thick organo-chlorinated plasma polymerized thin film. Ar/O2 pretreatment allows the removal of organic residues, coming from drawing lubricants, and induces external growth of zinc oxide. The plasma layer has to be preferably deposited at low power to conserve sufficient hydrocarbon moieties. Surface analyses reveal the complex chemical mechanism behind the establishment of strong adhesion levels, more than five times higher after the plasma treatment. During the vulcanization step, superficial ZnO reacts with the chlorinated species of the thin film and is converted into porous and granular bump-shaped ZnwOxHyClz nanostructures. Together, rubber additives diffuse through the plasma layer and lead to the formation of zinc sulfide on the substrate surface. Hence, two distinct interfaces, rubber/thin film and thin film/substrate, are established. On the basis of these observations, hypotheses explaining the high bonding strength results are formulated.

  18. Leidenfrost Vapor Layers Reduce Drag without the Crisis in High Viscosity Liquids

    KAUST Repository

    Vakarelski, Ivan Uriev


    The drag coefficient CD of a solid smooth sphere moving in a fluid is known to be only a function of the Reynolds number Re and diminishes rapidly at the drag crisis around Re∼3×105. A Leidenfrost vapor layer on a hot sphere surface can trigger the onset of the drag crisis at a lower Re. By using a range of high viscosity perfluorocarbon liquids, we show that the drag reduction effect can occur over a wide range of Re, from as low as ∼600 to 105. The Navier slip model with a viscosity dependent slip length can fit the observed drag reduction and wake shape. © 2016 American Physical Society.

  19. Combinatorial atmospheric pressure chemical vapor deposition of graded TiO₂-VO₂ mixed-phase composites and their dual functional property as self-cleaning and photochromic window coatings. (United States)

    Wilkinson, Mia; Kafizas, Andreas; Bawaked, Salem M; Obaid, Abdullah Y; Al-Thabaiti, Shaeel A; Basahel, Sulaiman N; Carmalt, Claire J; Parkin, Ivan P


    A combinatorial film with a phase gradient from V:TiO₂ (V: Ti ≥ 0.08), through a range of TiO₂-VO₂ composites, to a vanadium-rich composite (V: Ti = 1.81) was grown by combinatorial atmospheric pressure chemical vapor deposition (cAPCVD). The film was grown from the reaction of TiCl₄, VCl₄, ethyl acetate (EtAc), and H₂O at 550 °C on glass. The gradient in gas mixtures across the reactor induced compositional film growth, producing a single film with numerous phases and compositions at different positions. Seventeen unique positions distributed evenly along a central horizontal strip were investigated. The physical properties were characterized by wavelength dispersive X-ray (WDX) analysis, X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and UV-visible spectroscopy. The functional properties examined included the degree of photoinduced hydrophilicity (PIH), UVC-photocatalysis, and thermochromism. Superhydrophilic contact angles could be achieved at all positions, even within a highly VO₂-rich composite (V: Ti = 1.81). A maximum level of UVC photocatalysis was observed at a position bordering the solubility limit of V:TiO₂ (V: Ti ≈ 0.21) and fragmentation into a mixed-phase composite. Within the mixed-phase TiO₂: VO₂ composition region (V: Ti = 1.09 to 1.81) a decrease in the semiconductor-to-metal transition temperature of VO₂ from 68 to 51 °C was observed.

  20. Improving Liquid Entry Pressure of Polyvinylidene Fluoride (PVDF Membranes by Exploiting the Role of Fabrication Parameters in Vapor-Induced Phase Separation VIPS and Non-Solvent-Induced Phase Separation (NIPS Processes

    Directory of Open Access Journals (Sweden)

    Faisal Abdulla AlMarzooqi


    Full Text Available Polyvinylidene fluoride (PVDF is a popular polymer material for making membranes for several applications, including membrane distillation (MD, via the phase inversion process. Non-solvent-induced phase separation (NIPS and vapor-induced phase separation (VIPS are applied to achieve a porous PVDF membrane with low mass-transfer resistance and high contact angle (hydrophobicity. In this work, firstly, the impacts of several preparation parameters on membrane properties using VIPS and NIPS were studied. Then, the performance of the selected membrane was assessed in a lab-scale direct-contact MD (DCMD unit. The parametric study shows that decreasing PVDF concentration while increasing both relative humidity (RH and exposure time increased the contact angle and bubble-point pore size (BP. Those trends were investigated further by varying the casting thickness. At higher casting thicknesses and longer exposure time (up to 7.5 min, contact angle (CA increased but BP significantly decreased. The latter showed a dominant trend leading to liquid entry pressure (LEP increase with thickness.

  1. Effect of growth conditions on the Al composition and optical properties of Al x Ga 1−x N layers grown by atmospheric-pressure metal organic vapor phase epitaxy

    KAUST Repository

    Soltani, S.


    The effect of growth conditions on the Al composition and optical properties of AlxGa1-xN layers grown by atmospheric-pressure metal organic vapor phase epitaxy is investigated. The Al content of the samples is varied between 3.0% and 9.3% by changing the gas flow rate of either trimethylaluminum (TMA) or trimethylgallium (TMG) while other growth parameters are kept constant. The optical properties of the AlxGa1-xN layers are studied by photoreflectance and time-resolved photoluminescence (TR-PL) spectroscopies. A degeneration in the material quality of the samples is revealed when the Al content is increased by increasing the TMA flow rate. When the TMG flow rate is decreased with a fixed TMA flow rate, the Al content of the AlxGa1-xN layers is increased and, furthermore, an improvement in the optical properties corresponding with an increase in the PL decay time is observed. (C) 2017 Elsevier B.V. All rights reserved.

  2. Modelling and simulation of the steam line, the high and low pressure turbines and the pressure regulator for the SUN-RAH nucleo electric university simulator; Modelado y simulacion de la linea de vapor, las turbinas de alta y de baja presion y el regulador de presion para el simulador universitario de nucleo electricas SUN RAH

    Energy Technology Data Exchange (ETDEWEB)

    Lopez R, A. [DEPFI, Campus Morelos, en IMTA Jiutepec, Morelos, UNAM (Mexico)]. e-mail:


    In the following article the development of a simulator that allows to represent the dynamics of the following systems: steam line, nozzle, vapor separator, reheater, high pressure turbine, low pressure turbine, power generator and the pressure regulator of a nucleo electric power station. We start from the supposition that this plant will be modeled from a nuclear reactor type BWR (Boiling Water Reactor), using models of reduced order that represent the more important dynamic variables of the physical processes that happen along the steam line until the one generator. To be able to carry out the simulation in real time the Mat lab mathematical modeling software is used, as well as the specific simulation tool Simulink. It is necessary to point out that the platform on which the one is executed the simulator is the Windows operating system, to allow the intuitive use that only this operating system offers. The above-mentioned obeys to that the objective of the simulator it is to help the user to understand some of the dynamic phenomena that are present in the systems of a nuclear plant, and to provide a tool of analysis and measurement of variables to predict the desirable behavior of the same ones. The model of a pressure controller for the steam lines, the high pressure turbine and the low pressure turbine is also presented that it will be the one in charge of regulating the demand of the system according to the characteristics and critic restrictions of safety and control, assigned according to those wanted parameters of performance of this system inside the nucleo electric plant. This simulator is totally well defined and it is part of the University student nucleo electric simulator with Boiling Water Reactor (SUN-RAH), an integral project and of greater capacity. (Author)

  3. Referred Air Method 25E: Determination of a Vapor Phase Organic Concentration in Waste Samples (United States)

    This method is applicable for determining the vapor pressure of waste. The headspace vapor of the sample is analyzed for carbon content by a headspace analyzer, which uses a flame ionization detector (FID).

  4. Mixed-Organic-Cation (FA)x(MA)1-xPbI3 Planar Perovskite Solar Cells with 16.48% Efficiency via a Low-Pressure Vapor-Assisted Solution Process. (United States)

    Chen, Jing; Xu, Jia; Xiao, Li; Zhang, Bing; Dai, Songyuan; Yao, Jianxi


    Compared to that of methylammonium lead iodide perovskite (MAPbI3), formamidinium lead iodide perovskite (FAPbI3) has a smaller energy band gap and greater potential efficiency. To prevent the transformation of α-FAPbI3 to δ-FAPbI3, preparation of (FA)x(MA)1-xPbI3 was regarded as an effective route. Usually, the planar (FA)x(MA)1-xPbI3 perovskite solar cells are fabricated by a solution process. Herein, we report a low-pressure vapor-assisted solution process (LP-VASP) for the growth of (FA)x(MA)1-xPbI3 perovskite solar cells that features improved electron transportation, uniform morphology, high power conversion efficiency (PCE), and better crystal stability. In LP-VASP, the (FA)x(MA)1-xPbI3 films were formed by the reaction between the PbI2 film with FAI and MAI vapor in a very simple vacuum oven. LP-VASP is an inexpensive way to batch-process solar cells, avoiding the repeated deposition solution process for PbI2 films, and the device had a low cost. We demonstrate that, with an increase in the MAI content, the (101) peak position of FAPbI3 shifts toward the (110) peak position of MAPbI3, the (FA)x(MA)1-xPbI3 perovskites are stable, and no decomposition or phase transition is observed after 14 days. The photovoltaic performance was effectively improved by the introduction of MA+ with the highest efficiency being 16.48% under conditions of 40 wt % MAI. The carrier lifetime of (FA)x(MA)1-xPbI3 perovskite films is approximately three times longer than that of pure FAPbI3. Using this process, solar cells with a large area of 1.00 cm2 were fabricated with the PCE of 8.0%.

  5. Measurement of HVAC system performance and local ventilation using passive perfluorocarbon tracer technology

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, R.N.; Goodrich, R.W.


    In April of 1993, two (2) perfluorocarbon tracer (PFT) ventilation/indoor air quality assessment tests were performed in the Gleeson Hall building of the SUNY Farmingdale campus. The building was being modified, in part, as a result of significant occupant complaints of perceived poor air quality. The four story building had a basement first floor with air supplied normally by an HVAC system labelled as AC1. During this study, AC1 was inoperational and the basement interior rooms (walls) were primarily gone; the other three floors were still being used for classes. It is possible that a sense of poor air quality may have been perceived by first-floor occupants because they were working in the basement, but this issue could not be addressed. The second floor had two (2) lecture halls--Rm 202 (handled by AC4) and Rm 204 (handled by AC5); the balance of the second floor interior rooms and corridors was split between two other air handling systems, AC2 for the west side of the building and AC3 for the east side. The remaining 3rd and 4th floors were also split about evenly between AC2 and AC3. The perimeter rooms, equipped with wall units having their own outside air (OA) source plus centralized return air (RA) bypasses, were not included in this testing which was restricted to the basement floor (1st floor) and the four operating air handling systems, AC2 to AC5, during Test 1 and only AC2 to AC5 during Test 2. Two types of tests were performed using the full suite of 5 PFT types available. The first test was designed to measure the infiltration, exfiltration, and air exchange between the 5 AC zones above and the second test used the 5th tracer, which had been in the basement, as a distributed source throughout the four other zones to act as a surrogate pollutant source. This report provides final conclusions of both tests and suggestions regarding its usefulness in similar building ventilation and indoor air quality assessments.

  6. Vapor pressure and specific electrical conductivity in the solid and molten H2O-CsH2PO4-CsPO3 system—a novel electrolyte for water electrolysis at ~ 225–400 °C

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey Valerievich; Berg, Rolf W.; Bjerrum, Niels J.


    cells. Freshly prepared 99.7 ± 0.3% gravimetric pure CDP with correct X-ray diffraction and DSC diagram melted at ~ 345 °C. The vapor pressures, above CDP alone and mixed with 20–50 mol% CsPO3 or 13 mol% H2O, were determined in sealed ampoules up to 355 °C by means of Raman spectroscopy based...

  7. Low-voltage back-gated atmospheric pressure chemical vapor deposition based graphene-striped channel transistor with high-κ dielectric showing room-temperature mobility > 11 000 cm2/V·s

    KAUST Repository

    Smith, Casey


    Utilization of graphene may help realize innovative low-power replacements for III-V materials based high electron mobility transistors while extending operational frequencies closer to the THz regime for superior wireless communications, imaging, and other novel applications. Device architectures explored to date suffer a fundamental performance roadblock due to lack of compatible deposition techniques for nanometer-scale dielectrics required to efficiently modulate graphene transconductance (gm) while maintaining low gate capacitance-voltage product (CgsVgs). Here we show integration of a scaled (10 nm) high-κ gate dielectric aluminum oxide (Al2O3) with an atmospheric pressure chemical vapor deposition (APCVD)-derived graphene channel composed of multiple 0.25 μm stripes to repeatedly realize room-temperature mobility of 11 000 cm 2/V·s or higher. This high performance is attributed to the APCVD graphene growth quality, excellent interfacial properties of the gate dielectric, conductivity enhancement in the graphene stripes due to low t ox/Wgraphene ratio, and scaled high-κ dielectric gate modulation of carrier density allowing full actuation of the device with only ±1 V applied bias. The superior drive current and conductance at Vdd = 1 V compared to other top-gated devices requiring undesirable seed (such as aluminum and poly vinyl alcohol)-assisted dielectric deposition, bottom gate devices requiring excessive gate voltage for actuation, or monolithic (nonstriped) channels suggest that this facile transistor structure provides critical insight toward future device design and process integration to maximize CVD-based graphene transistor performance. © 2013 American Chemical Society.

  8. Overview of chemical vapor infiltration

    Energy Technology Data Exchange (ETDEWEB)

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


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

  9. Improving the performance of phase-change perfluorocarbon droplets for medical ultrasonography: current progress, challenges, and prospects. (United States)

    Sheeran, Paul S; Dayton, Paul A


    Over the past two decades, perfluorocarbon (PFC) droplets have been investigated for biomedical applications across a wide range of imaging modalities. More recently, interest has increased in "phase-change" PFC droplets (or "phase-change" contrast agents), which can convert from liquid to gas with an external energy input. In the field of ultrasound, phase-change droplets present an attractive alternative to traditional microbubble agents for many diagnostic and therapeutic applications. Despite the progress, phase-change PFC droplets remain far from clinical implementation due to a number of challenges. In this review, we survey our recent work to enhance the performance of phase-change agents for ultrasound through a variety of techniques in order to provide increased efficacy in therapeutic applications of ultrasound and enable previously unexplored applications in diagnostic and molecular imaging.

  10. Improving the Performance of Phase-Change Perfluorocarbon Droplets for Medical Ultrasonography: Current Progress, Challenges, and Prospects

    Directory of Open Access Journals (Sweden)

    Paul S. Sheeran


    Full Text Available Over the past two decades, perfluorocarbon (PFC droplets have been investigated for biomedical applications across a wide range of imaging modalities. More recently, interest has increased in “phase-change” PFC droplets (or “phase-change” contrast agents, which can convert from liquid to gas with an external energy input. In the field of ultrasound, phase-change droplets present an attractive alternative to traditional microbubble agents for many diagnostic and therapeutic applications. Despite the progress, phase-change PFC droplets remain far from clinical implementation due to a number of challenges. In this review, we survey our recent work to enhance the performance of phase-change agents for ultrasound through a variety of techniques in order to provide increased efficacy in therapeutic applications of ultrasound and enable previously unexplored applications in diagnostic and molecular imaging.

  11. Effect of oxygen breathing and perfluorocarbon emulsion treatment on air bubbles in adipose tissue during decompression sickness

    DEFF Research Database (Denmark)

    Randsoe, T; Hyldegaard, O


    Decompression sickness (DCS) after air diving has been treated with success by means of combined normobaric oxygen breathing and intravascular perfluorocarbon (PFC) emulsions causing increased survival rate and faster bubble clearance from the intravascular compartment. The beneficial PFC effect...... has been explained by the increased transport capacity of oxygen and inert gases in blood. However, previous reports have shown that extravascular bubbles in lipid tissue of rats suffering from DCS will initially grow during oxygen breathing at normobaric conditions. We hypothesize that the combined...... effect of normobaric oxygen breathing and intravascular PFC infusion could lead to either enhanced extravascular bubble growth on decompression due to the increased oxygen supply, or that PFC infusion could lead to faster bubble elimination due to the increased solubility and transport capacity in blood...

  12. 40 CFR 796.1950 - Vapor pressure. (United States)


    ... coat the liquid on glass beads and to pack the holder in the designated place with these beads. (D) At... liquid samples, at the end of the sampling time, the front and backup sorbent sections are analyzed...

  13. Impairments in the Nanostructure of Red Blood Cell Membranes in Acute Blood Loss and Their Correction with Perfluorocarbon Emulsion

    Directory of Open Access Journals (Sweden)

    V. V. Moroz


    Full Text Available Objective: to study impairments in the nanostructure of red blood cell membranes in acute blood loss and methods to correct the membrane structures with perfluorocarbon emulsion. Materials and methods. Experiments were carried out on Nembutal-anesthesized outbred rats. The model of a terminal state was 60-minute hypovolemic hypotension, followed by blood reinfusion and addition of perfluorane or Ringer’s solution. Images of fragments of the red blood cell membrane surface structure were obtained using a Femtoscan atomic force microscope (AFM. Twenty-seven experiments were performed; 186 cells were scanned on the AFM, which provided 720 images of three orders. Results. The paper shows the time course of changes in the index hi for different phases of an experiment. After 5-minute hypotension, h1 increased by more than 4.3 times and after 60-minute hypotension, this value decreased to 4.7 nm. The second-order height rose linearly at the stages: control — at 5 minutes — at 60 minutes of hypotension. At 60 minutes of hypotension, the first- and second-order heights were similar. At 5 minutes of hypotension, the third-order surface slightly changed — it increased by 1.5-fold. But at 60 minutes of hypotension, the changes in the fine structures of the membrane became great — h3 increased by 6.3 times. Conclusion. Blood loss has shown to induce impairments in the microstructure of red blood cell membranes at all levels of its organization: flick in the range of 600—1000 nm, spectrin matrix at 150—350 nm, proteins, band 3, at 30—80 nm. The per-fluorocarbon emulsion «Perftoran» exerts a pronounced modulatory effect on the red blood cell membrane nanostructure at all steps of its organization, by restoring the membrane nanostructure practically to the control level. Key words: blood loss, red blood cell membrane, nanostructure, atomic force microscopy.

  14. Using CO2 Lidar for Standoff Detection of a Perfluorocarbon Tracer in Air

    Energy Technology Data Exchange (ETDEWEB)

    Heiser,J.H.; Smith, S.; Sedlacek, A.


    The Tag, Track and Location System Program (TTL) is investigating the use of PFTs as tracers for tagging and tracking items of interest or fallen soldiers. In order for the tagging and tracking to be valuable there must be a location system that can detect the PFTs. This report details the development of an infrared lidar platform for standoff detection of PFTs released into the air from a tagged object or person. Furthering work performed using a table top lidar system in an indoor environment; a mobile mini lidar platform was assembled using an existing Raman lidar platform, a grating tunable CO{sub 2} IR laser, Judson HgCdTe detector and miscellaneous folding optics and electronics. The lidar achieved {approx}200 ppb-m sensitivity in laboratory and indoor testing and was then successfully demonstrated at an outdoor test. The lidar system was able to detect PFTs released into a vehicle from a distance of 100 meters. In its final, fully optimized configuration the lidar was capable of repeatedly detecting PFTs in the air released from tagged vehicles. Responses were immediate and clear. This report details the results of a proof-of-concept demonstration for standoff detection of a perfluorocarbon tracer (PFT) using infrared lidar. The project is part of the Tag, Track and Location System Program and was performed under a contract with Tracer Detection Technology Corp. with funding from the Office of Naval Research. A lidar capable of detecting PFT releases at distance was assembled by modifying an existing Raman lidar platform by incorporating a grating tunable CO{sub 2} IR laser, Judson HgCdTe detector and miscellaneous folding optics and electronics. The lidar achieved {approx}200 ppb-m sensitivity in laboratory and indoor testing and was successfully demonstrated at an outdoor test. The demonstration test (scripted by the sponsor) consisted of three parked cars, two of which were tagged with the PFT. The cars were located 70 (closest) to 100 meters (farthest

  15. Physical model for vaporization


    Garai, Jozsef


    Based on two assumptions, the surface layer is flexible, and the internal energy of the latent heat of vaporization is completely utilized by the atoms for overcoming on the surface resistance of the liquid, the enthalpy of vaporization was calculated for 45 elements. The theoretical values were tested against experiments with positive result.

  16. Thermodynamics and Kinetics of Silicate Vaporization (United States)

    Jacobson, Nathan S.; Costa, Gustavo C. C.


    Silicates are a common class of materials that are often exposed to high temperatures. The behavior of these materials needs to be understood for applications as high temperature coatings in material science as well as the constituents of lava for geological considerations. The vaporization behavior of these materials is an important aspect of their high temperature behavior and it also provides fundamental thermodynamic data. The application of Knudsen effusion mass spectrometry (KEMS) to silicates is discussed. There are several special considerations for silicates. The first is selection of an appropriate cell material, which is either nearly inert or has well-understood interactions with the silicate. The second consideration is proper measurement of the low vapor pressures. This can be circumvented by using a reducing agent to boost the vapor pressure without changing the solid composition or by working at very high temperatures. The third consideration deals with kinetic barriers to vaporization. The measurement of these barriers, as encompassed in a vaporization coefficient, is discussed. Current measured data of rare earth silicates for high temperature coating applications are discussed. In addition, data on magnesium-iron-silicates (olivine) are presented and discussed.

  17. Numerical simulation of superheated vapor bubble rising in stagnant liquid (United States)

    Samkhaniani, N.; Ansari, M. R.


    In present study, the rising of superheated vapor bubble in saturated liquid is simulated using volume of fluid method in OpenFOAM cfd package. The surface tension between vapor-liquid phases is considered using continuous surface force method. In order to reduce spurious current near interface, Lafaurie smoothing filter is applied to improve curvature calculation. Phase change is considered using Tanasawa mass transfer model. The variation of saturation temperature in vapor bubble with local pressure is considered with simplified Clausius-Clapeyron relation. The couple velocity-pressure equation is solved using PISO algorithm. The numerical model is validated with: (1) isothermal bubble rising and (2) one-dimensional horizontal film condensation. Then, the shape and life time history of single superheated vapor bubble are investigated. The present numerical study shows vapor bubble in saturated liquid undergoes boiling and condensation. It indicates bubble life time is nearly linear proportional with bubble size and superheat temperature.

  18. Vaporizers for medical marijuana. (United States)

    Mirken, B


    A major concern about the medical use of marijuana is the harmful effects that come from smoking it. Vaporizers are designed to release the active ingredients in marijuana without burning it, and therefore do not release the harmful substances found in the marijuana smoke. The Institute of Medicine recommends against the long-term medical use of smoked marijuana because of carcinogens and other chemicals in the smoke. Several vaporizers are on the market, but they have not been tested in the laboratory yet. A review of two vaporizers is given. Contact information is provided.

  19. Second Vapor-Level Sensor For Vapor Degreaser (United States)

    Painter, Nance M.; Burley, Richard K.


    Second vapor-level sensor installed at lower level in vapor degreaser makes possible to maintain top of vapor at that lower level. Evaporation reduced during idle periods. Provides substantial benefit, without major capital cost of building new vapor degreaser with greater freeboard height.

  20. Steam regulation for 5 MW back-pressure units when a failure occurs in the Los Humeros, Pue., field, Mexico; Regulacion del vapor en caso de falla a unidades a contrapresion de 5 MW en el campo de Los Humeros, Pue., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Rosales Lopez, Cesar [Comision Federal de Electricidad, Puebla (Mexico)]. E-mail:


    Four out of the seven back-pressure power units of 5 MW operating in the Los Humeros geothermal field, State of Puebla, Mexico, are fed by one steam pipe gathering the steam produced by nine wells. When a failure occurred in any of the units and the excedence valve had to be open to deviate the steam, a decrease in the steam flow for the remaining units was noted, along with lower electrical generation. The cause for that is analyzed and explained in this paper by comparing the interconnected steam supply system to an electric circuit. A way to maintain a uniform and continuous supply of steam in the Los Humeros field has been found. It was implemented several months ago and the problem has not reoccurred. [Spanish] Cuatro de las siete unidades de 5 MW a contrapresion que operan en el campo geotermico de Los Humeros, Puebla, son alimentadas por un solo vaporducto que reune el vapor de nueve pozos productores. Cuando ocurria una falla en alguna de estas unidades y se abria por completo la valvula de excedencia para desviar el vapor, se observaba una reduccion en el flujo de vapor que llegaba a las otras tres unidades, lo que a su vez ocasionaba que la generacion de electricidad se redujera notoriamente. En este trabajo se analiza y explica la causa de ello, mediante la comparacion de este sistema interconectado de suministro de vapor con un circuito electrico, y se explica la solucion que se encontro e implemento en el campo de Los Humeros para regular el suministro continuo y uniforme de vapor, con resultados satisfactorios a varios meses de su implementacion en las cuatro unidades interconectadas.

  1. Condensers for measuring steam quality at the inlet of back-pressure units of the Los Azufres, Mich., geothermal field; Condensadores para medir la calidad del vapor a la entrada de las turbinas a contrapresion del campo geotermico de Los Azufres, Mich.

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval Medina, Fernando; Gonzalez Gonzalez, Rubi; Reyes Delgado, Lisette; Medina Martinez, Moises [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia de Los Azufres (Mexico)]. E-mail:


    Electrical conductivity is an indirect measurement of the quality of the steam supplied to power units. In the Los Azufres, Mich., geothermal field, the electrical conductivity once was measured in a discrete and periodic way by condensing steam samples through a water-cooled condenser. In an attempt to continuously measure conductivity, conductivity meters were installed where the units discharged, but the values proved unstable and unrepresentative. Thereafter, taking into account that steam quality should be measured at the steam delivery-reception point, equipment was designed and tested for continuously condensing steam. Finally it was possible to get an air-cooled condenser able to condense 500 milliliters per minute, enough to collect a representative flow of the steam and to measure its electrical conductivity. The equipment was installed in all seven back-pressure units operating in the field and to date has been operating in an optimal manner. [Spanish] La conductividad electrica es una medida indirecta de la calidad del vapor que se suministra a las unidades turbogeneradoras. En el campo geotermico de Los Azufres, Mich., la conductividad electrica se media en forma puntual y periodica, condensando muestras de vapor por medio de un serpentin enfriado con agua. Despues, ante la necesidad de medirla en forma continua, se instalaron conductivimetros en las descargas de las unidades, pero los valores resultaron muy inestables y poco representativos. Considerando, ademas, que la calidad del vapor debe medirse en el punto de entrega-recepcion, se disenaron y probaron equipos para condensar vapor de manera continua, lograndose construir un condensador enfriado por aire que logra condensar un flujo de 500 mililitros por minuto, cantidad suficiente para tener un flujo representativo del vapor que alimenta a las turbinas y medirle su conductividad electrica. Se instalaron estos equipos en las siete unidades turbogeneradoras a contrapresion que funcionan en el campo

  2. Radiative Vaporization of Graphite in the Temperature Range of 4000 to 4500 deg K (United States)

    Lundell, John H.; Dickey, Robert R.


    The vaporization of graphite under intense laser radiation is considered both theoretically and experimentally. Under intense radiation, the mass-loss rate can be high enough to cause the flow in the laser plume to be supersonic. Under these conditions, the vaporization process is coupled to the plume gasdynamics. Experimental results are presented for surface temperatures of 3985 to 4555 K and mass-loss rates from 0.52 to 27.0 g/sq cm sec. The data are used to determine the vapor pressure of graphite in a range of 2 to 11 atm, and the results are shown to be in good agreement with the JANAF vapor pressure curve, if the vaporization coefficients are unity. The assumption of unity vaporization coefficients is shown to be reasonable by a comparison of the present results with other recent vapor pressure results for graphite.

  3. Vapor Control Layer Recommendations

    Energy Technology Data Exchange (ETDEWEB)



    This information sheet describes the level of vapor control required on the interior side of framed walls with typical fibrous cavity insulation (fibreglass, rockwool, or cellulose, based on DOE climate zone of construction.

  4. Esquema de análisis para el cálculo del equilibrio líquido vapor de sistemas binarios asimétricos que contienen dióxido de carbono a altas presiones = Schematic analysis for the calculation of vapor liquid equilibrium for asymmetric binary systems containing carbon dioxide at high pressures


    Trejos Montoya, Victor Manuel


    El presente trabajo establece el desarrollo de un esquema de análisis del equilibrio líquido vapor de sistemas binarios asimétricos que contienen dióxido de carbono a altas presiones. Dicho esquema integra el ajuste de parámetros del equilibrio líquido vapor, análisis de funciones objetivo, reglas de mezclado EOS-Gex y consistencia termodinámica de este tipo de mezclas con el fin de mejorar las etapas de diseño y la puesta en marcha de equipos que operan con fluidos supercríticos / Abstrac...

  5. Tolman's length and limiting supersaturation of vapor (United States)

    Alekseechkin, Nikolay V.


    The classical Kelvin formula for the equilibrium vapor pressure over a droplet of radius R is extended to small radii and vapor non-ideality, from where the limiting supersaturation condition is obtained by relating the point R = 0 to the value of limiting (spinodal) supersaturation of vapor. The analysis of different dependences of the Tolman length on radius, δ (R) , obeying this condition suggests that (i) the value of δ (0) is positive and the function δ (R) decreases with increasing radius; (ii) the curvature effect (the dependence of surface tension on radius) in the nucleation region is determined by the value of δ (0) . At the same time, this effect is weakly sensitive to the form of the function δ (R) and insensitive to its asymptotic value δ∞ .

  6. Solvent vapor induced morphology transition in thin film of cylinder forming diblock copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Li Yuhu; Huang Haiying [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); He Tianbai, E-mail: [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Gong Yumei, E-mail: [School of Chemical and Material, Dalian Polytechnic University, Dalian 116034 (China)


    The morphology formation and transition of thin film of a cylinder-forming polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer annealed under 1,1,2-trichloroethane (Tri-CE), toluene (Tol), and their binary mixed solvent vapors is investigated by using optical microscopy (OM) and transmission electronic microscopy (TEM). By modulating the annealing solvent vapor pressure and the preferential affinities, a detailed morphology evolution with increasing the vapor pressure and a series of morphologies depending on the preferential affinities have been observed. A phase diagram by plotting the morphologies as a function of the annealing solvent vapor pressure and its preferential affinity is subsequently constructed.

  7. Intraoperative Macula Protection by Perfluorocarbon Liquid for the Metallic Intraocular Foreign Body Removal during 23-Gauge Vitrectomy. (United States)

    Rejdak, Robert; Choragiewicz, Tomasz; Moneta-Wielgos, Joanna; Wrzesinska, Dominika; Borowicz, Dorota; Forlini, Matteo; Jünemann, Anselm G; Nowomiejska, Katarzyna


    Purpose. To evaluate visual and safety outcomes of 23-gauge (G) pars plana vitrectomy (PPV) with application of perfluorocarbon liquid (PFCL) for intraoperative protection of the macula during intraocular foreign body (IOFB) removal. Methods. Retrospective study of 42 patients who underwent 23 G PPV for IOFB removal from posterior segment with intraoperative PFCL application for the macula shielding. Collected data included corrected distance visual acuity (CDVA), size of IOFB, and complication rate. The mean follow-up period was 12 months. Results. The mean preoperative CDVA was 0.54 logMAR (SD 0.46), and the final mean CDVA was 0.68 logMAR (SD 0.66). All IOFBs were metallic with mean dimensions of 4.6 mm × 2.1 mm. Twenty-two IOFBs were removed through the corneal tunnel and 20 IOFBs through the sclerotomy. No intraoperative iatrogenic lesion of the macula was observed. As a tamponade, silicon oil was applied in 31 eyes, SF6 gas in 5 eyes, air in 4 eyes, and 2 eyes required no tamponade. Secondary retinal detachment was observed in 17% of cases, but at the end of the follow-up, all the retinas were attached. Conclusion. PFCL application during PPV is a safe method of protecting the macula from unexpected falling of the metallic IOFB during its removal.

  8. Erythrocyte-Membrane-Enveloped Perfluorocarbon as Nanoscale Artificial Red Blood Cells to Relieve Tumor Hypoxia and Enhance Cancer Radiotherapy. (United States)

    Gao, Min; Liang, Chao; Song, Xuejiao; Chen, Qian; Jin, Qiutong; Wang, Chao; Liu, Zhuang


    Hypoxia, a common feature within many types of solid tumors, is known to be closely associated with limited efficacy for cancer therapies, including radiotherapy (RT) in which oxygen is essential to promote radiation-induced cell damage. Here, an artificial nanoscale red-blood-cell system is designed by encapsulating perfluorocarbon (PFC), a commonly used artificial blood substitute, within biocompatible poly(d,l-lactide-co-glycolide) (PLGA), obtaining PFC@PLGA nanoparticles, which are further coated with a red-blood-cell membrane (RBCM). The developed PFC@PLGA-RBCM nanoparticles with the PFC core show rather efficient loading of oxygen, as well as greatly prolonged blood circulation time owing to the coating of RBCM. With significantly improved extravascular diffusion within the tumor mass, owing to their much smaller nanoscale sizes compared to native RBCs with micrometer sizes, PFC@PLGA-RBCM nanoparticles are able to effectively deliver oxygen into tumors after intravenous injection, leading to greatly relieved tumor hypoxia and thus remarkably enhanced treatment efficacy during RT. This work thus presents a unique type of nanoscale RBC mimic for efficient oxygen delivery into solid tumors, favorable for cancer treatment by RT, and potentially other types of therapy as well. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. High-intensity focused ultrasound sonothrombolysis: the use of perfluorocarbon droplets to achieve clot lysis at reduced acoustic power. (United States)

    Pajek, Daniel; Burgess, Alison; Huang, Yuexi; Hynynen, Kullervo


    The purpose of this study was to evaluate use of intravascular perfluorocarbon droplets to reduce the sonication power required to achieve clot lysis with high-intensity focused ultrasound. High-intensity focused ultrasound with droplets was initially applied to blood clots in an in vitro flow apparatus, and inertial cavitation thresholds were determined. An embolic model for ischemic stroke was used to illustrate the feasibility of this technique in vivo. Recanalization with intravascular droplets was achieved in vivo at 24 ± 5% of the sonication power without droplets. Recanalization occurred in 71% of rabbits that received 1-ms pulsed sonications during continuous intravascular droplet infusion (p = 0.041 vs controls). Preliminary experiments indicated that damage was confined to the ultrasonic focus, suggesting that tolerable treatments would be possible with a more tightly focused hemispheric array that allows the whole focus to be placed inside of the main arteries in the human brain. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  10. New mechanisms for non-porative ultrasound stimulation of cargo delivery to cell cytosol with targeted perfluorocarbon nanoparticles (United States)

    Soman, N. R.; Marsh, J. N.; Lanza, G. M.; Wickline, S. A.


    The cell membrane constitutes a major barrier for non-endocytotic intracellular delivery of therapeutic molecules from drug delivery vehicles. Existing approaches to breaching the cell membrane include cavitational ultrasound (with microbubbles), electroporation and cell-penetrating peptides. We report the use of diagnostic ultrasound for intracellular delivery of therapeutic bulky cargo with the use of molecularly targeted liquid perfluorocarbon (PFC) nanoparticles. To demonstrate the concept, we used a lipid with a surrogate polar head group, nanogold-DPPE, incorporated into the nanoparticle lipid monolayer. Melanoma cells were incubated with nanogold particles and this was followed by insonication with continuous wave ultrasound (2.25 MHz, 5 min, 0.6 MPa). Cells not exposed to ultrasound showed gold particles partitioned only in the outer bilayer of the cell membrane with no evidence of the intracellular transit of nanogold. However, the cells exposed to ultrasound exhibited numerous nanogold-DPPE components inside the cell that appeared polarized inside intracellular vesicles demonstrating cellular uptake and trafficking. Further, ultrasound-exposed cells manifested no incorporation of calcein or the release of lactate dehydrogenase. These observations are consistent with a mechanism that suggests that ultrasound is capable of stimulating the intracellular delivery of therapeutic molecules via non-porative mechanisms. Therefore, non-cavitational adjunctive ultrasound offers a novel paradigm in intracellular cargo delivery from PFC nanoparticles.

  11. Intraoperative Macula Protection by Perfluorocarbon Liquid for the Metallic Intraocular Foreign Body Removal during 23-Gauge Vitrectomy (United States)

    Moneta-Wielgos, Joanna; Wrzesinska, Dominika; Borowicz, Dorota; Forlini, Matteo; Jünemann, Anselm G.


    Purpose. To evaluate visual and safety outcomes of 23-gauge (G) pars plana vitrectomy (PPV) with application of perfluorocarbon liquid (PFCL) for intraoperative protection of the macula during intraocular foreign body (IOFB) removal. Methods. Retrospective study of 42 patients who underwent 23 G PPV for IOFB removal from posterior segment with intraoperative PFCL application for the macula shielding. Collected data included corrected distance visual acuity (CDVA), size of IOFB, and complication rate. The mean follow-up period was 12 months. Results. The mean preoperative CDVA was 0.54 logMAR (SD 0.46), and the final mean CDVA was 0.68 logMAR (SD 0.66). All IOFBs were metallic with mean dimensions of 4.6 mm × 2.1 mm. Twenty-two IOFBs were removed through the corneal tunnel and 20 IOFBs through the sclerotomy. No intraoperative iatrogenic lesion of the macula was observed. As a tamponade, silicon oil was applied in 31 eyes, SF6 gas in 5 eyes, air in 4 eyes, and 2 eyes required no tamponade. Secondary retinal detachment was observed in 17% of cases, but at the end of the follow-up, all the retinas were attached. Conclusion. PFCL application during PPV is a safe method of protecting the macula from unexpected falling of the metallic IOFB during its removal. PMID:28553550

  12. Vapor concentration monitor (United States)

    Bayly, John G.; Booth, Ronald J.


    An apparatus for monitoring the concentration of a vapor, such as heavy water, having at least one narrow bandwidth in its absorption spectrum, in a sample gas such as air. The air is drawn into a chamber in which the vapor content is measured by means of its radiation absorption spectrum. High sensitivity is obtained by modulating the wavelength at a relatively high frequency without changing its optical path, while high stability against zero drift is obtained by the low frequency interchange of the sample gas to be monitored and of a reference sample. The variable HDO background due to natural humidity is automatically corrected.

  13. Measurement of alkali vapors in PFBC exhaust. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.H.D.; Swift, W.M.


    Under the auspices of the US Department of Energy through Morgantown Energy Technology Center, laboratory-scale studies were conducted to develop a regenerable activated-bauxite adsorbent (RABA) for use in an in situ regenerable activated-bauxite sorber alkali monitor (RABSAM). The RABSAM is a sampling probe that does not require a high-temperature/high-pressure sampling line for reliable measurement of alkali vapor in the exhaust of pressurized fluidized-bed combustor (PFBC). The RABA can be generated from the commercial grade activated bauxite by deactivating (or reacting) clay impurities in activated bauxite with NaCl or LiCl vapor. Under the atmospheric deactivation process, however, only a partial deactivation of clay impurities is achieved, probably due to limited access of NaCl or LiCl vapor into micropores of activated bauxite. Because LiCl vapor chemically reacts with alumina substrate of activated bauxite, resulting in pore enlargement, loss of pore surface area, and a decrease in the subsequent NaCl-vapor sorption capacity of the RABA, NaCl is a more suitable deactivation agent than LiCl vapor. In a simulated PFBC exhaust environment, the RABA behaves similarly to fresh activated bauxite in capturing NaCl vapor from the simulated PFBC exhaust. Based on results of this work, we recommend generating chemically and thermally stable RABA by deactivating clay impurities of commercial grade activated bauxite with NaCl or KCl vapor under simulated PFBC exhaust environment, that is, high-temperature, high-pressure, and high concentrations of NaCl or KCl vapor in simulated PFBC exhaust compositions.

  14. An update: improvements in imaging perfluorocarbon-mounted plant leaves with implications for studies of plant pathology, physiology, development and cell biology.

    Directory of Open Access Journals (Sweden)

    George R Littlejohn


    Full Text Available Plant leaves are optically complex, which makes them difficult to image by light microscopy. Careful sample preparation is therefore required to enable researchers to maximise the information gained from advances in fluorescent protein labelling, cell dyes and innovations in microscope technologies and techniques. We have previously shown that mounting leaves in the non-toxic, non-fluorescent perfluorocarbon (PFC, perfluorodecalin (PFD enhances the optical properties of the leaf with minimal impact on physiology. Here, we assess the use of the perfluorocarbons PFD, and perfluoroperhydrophenanthrene (PP11 for in vivo plant leaf imaging using 4 advanced modes of microscopy: laser scanning confocal microscopy (LSCM, Two-photon fluorescence (TPF microscopy, second harmonic generation (SHG microscopy and stimulated Raman scattering (SRS microscopy. For every mode of imaging tested, we observed an improved signal when leaves were mounted in PFD or in PP11, compared to mounting the samples in water. Using an image analysis technique based on autocorrelation to quantitatively assess LSCM image deterioration with depth, we show that PP11 outperformed PFD as a mounting medium by enabling the acquisition of clearer images deeper into the tissue. In addition, we show that SRS microscopy can be used to image perfluorocarbons directly in the mesophyll and thereby easily delimit the negative space within a leaf, which may have important implications for studies of leaf development. Direct comparison of on and off resonance SRS micrographs show that PFCs do not to form intracellular aggregates in live plants. We conclude that the application of PFCs as mounting media substantially increases advanced microscopy image quality of living mesophyll and leaf vascular bundle cells.

  15. Operating a radio-frequency plasma source on water vapor. (United States)

    Nguyen, Sonca V T; Foster, John E; Gallimore, Alec D


    A magnetically enhanced radio-frequency (rf) plasma source operating on water vapor has an extensive list of potential applications. In this work, the use of a rf plasma source to dissociate water vapor for hydrogen production is investigated. This paper describes a rf plasma source operated on water vapor and characterizes its plasma properties using a Langmuir probe, a residual gas analyzer, and a spectrometer. The plasma source operated first on argon and then on water vapor at operating pressures just over 300 mtorr. Argon and water vapor plasma number densities differ significantly. In the electropositive argon plasma, quasineutrality requires n(i) approximately = n(e), where n(i) is the positive ion density. But in the electronegative water plasma, quasineutrality requires n(i+) = n(i-) + n(e). The positive ion density and electron density of the water vapor plasma are approximately one and two orders of magnitude lower, respectively, than those of argon plasma. These results suggest that attachment and dissociative attachment are present in electronegative water vapor plasma. The electron temperature for this water vapor plasma source is between 1.5 and 4 eV. Without an applied axial magnetic field, hydrogen production increases linearly with rf power. With an axial magnetic field, hydrogen production jumps to a maximum value at 500 W and then saturates with rf power. The presence of the applied axial magnetic field is therefore shown to enhance hydrogen production.

  16. Distributions, long term trends and emissions of four perfluorocarbons in remote parts of the atmosphere and firn air (United States)

    Laube, J. C.; Hogan, C.; Newland, M. J.; Mani, F. S.; Fraser, P. J.; Brenninkmeijer, C. A. M.; Martinerie, P.; Oram, D. E.; Röckmann, T.; Schwander, J.; Witrant, E.; Mills, G. P.; Reeves, C. E.; Sturges, W. T.


    We report the first data set of atmospheric abundances for the following four perfluoroalkanes: n-decafluorobutane (n-C4F10), n-dodecafluoropentane (n-C5F12), n-tetradecafluorohexane (n-C6F14) and n-hexadecafluoroheptane (n-C7F16). All four compounds could be detected and quantified in air samples from remote locations in the Southern Hemisphere (at Cape Grim, Tasmania, archived samples dating back to 1978) and the upper troposphere (a passenger aircraft flying from Germany to South Africa). Further observations originate from air samples extracted from deep firn in Greenland and allow trends of atmospheric abundances in the earlier 20th century to be inferred. All four compounds were not present in the atmosphere prior to the 1960s. n-C4F10 and n-C5F12 were also measured in samples collected in the stratosphere with the data indicating that they have no significant sinks in this region. Emissions were inferred from these observations and found to be comparable with emissions from the EDGAR database for n-C6F14. However, emissions of n-C4F10, n-C5F12 and n-C7F16 were found to differ by up to five orders of magnitude between our approach and the database. Although the abundances of the four perfluorocarbons reported here are currently small (less than 0.3 parts per trillion) they have strong Global Warming Potentials several thousand times higher than carbon dioxide (on a 100-yr time horizon) and continue to increase in the atmosphere. We estimate that the sum of their cumulative emissions reached 325 million metric tonnes CO2 equivalent at the end of 2009.

  17. Water vaporization on Ceres (United States)

    A'Hearn, Michael F.; Feldman, Paul D.


    A search is presently conducted for OH generated by the photodissociation of atmospheric water vapor in long-exposure IUE spectra of the region around Ceres. A statistically significant detection of OH is noted in an exposure off the northern limb of Ceres after perihelion. The amount of OH is consistent with a polar cap that might be replenished during winter by subsurface percolation, but which dissipates in summer.

  18. Released air during vapor and air cavitation

    Energy Technology Data Exchange (ETDEWEB)

    Jablonská, Jana, E-mail:; Kozubková, Milada, E-mail: [VŠB-Technical University of Ostrava, Faculty of Mechanical Engineering, Department of Hydromechanics and Hydraulic Equipment, 17. listopadu 15, 708 33 Ostrava-Poruba (Czech Republic)


    Cavitation today is a very important problem that is solved by means of experimental and mathematical methods. The article deals with the generation of cavitation in convergent divergent nozzle of rectangular cross section. Measurement of pressure, flow rate, temperature, amount of dissolved air in the liquid and visualization of cavitation area using high-speed camera was performed for different flow rates. The measurement results were generalized by dimensionless analysis, which allows easy detection of cavitation in the nozzle. For numerical simulation the multiphase mathematical model of cavitation consisting of water and vapor was created. During verification the disagreement with the measurements for higher flow rates was proved, therefore the model was extended to multiphase mathematical model (water, vapor and air), due to release of dissolved air. For the mathematical modeling the multiphase turbulence RNG k-ε model for low Reynolds number flow with vapor and air cavitation was used. Subsequently the sizes of the cavitation area were verified. In article the inlet pressure and loss coefficient depending on the amount of air added to the mathematical model are evaluated. On the basis of the approach it may be create a methodology to estimate the amount of released air added at the inlet to the modeled area.

  19. Role of co-vapors in vapor deposition polymerization. (United States)

    Lee, Ji Eun; Lee, Younghee; Ahn, Ki-Jin; Huh, Jinyoung; Shim, Hyeon Woo; Sampath, Gayathri; Im, Won Bin; Huh, Yang-Il; Yoon, Hyeonseok


    Polypyrrole (PPy)/cellulose (PPCL) composite papers were fabricated by vapor phase polymerization. Importantly, the vapor-phase deposition of PPy onto cellulose was assisted by employing different co-vapors namely methanol, ethanol, benzene, water, toluene and hexane, in addition to pyrrole. The resulting PPCL papers possessed high mechanical flexibility, large surface-to-volume ratio, and good redox properties. Their main properties were highly influenced by the nature of the co-vaporized solvent. The morphology and oxidation level of deposited PPy were tuned by employing co-vapors during the polymerization, which in turn led to change in the electrochemical properties of the PPCL papers. When methanol and ethanol were used as co-vapors, the conductivities of PPCL papers were found to have improved five times, which was likely due to the enhanced orientation of PPy chain by the polar co-vapors with high dipole moment. The specific capacitance of PPCL papers obtained using benzene, toluene, water and hexane co-vapors was higher than those of the others, which is attributed to the enlarged effective surface area of the electrode material. The results indicate that the judicious choice and combination of co-vapors in vapor-deposition polymerization (VDP) offers the possibility of tuning the morphological, electrical, and electrochemical properties of deposited conducting polymers.

  20. Experimental study of external fuel vaporization (United States)

    Szetela, E. J.; Tevelde, J. A.


    The fuel properties used in the design of a flash vaporization system for aircraft gas turbine engines were evaluated in experiments using a flowing system to determine critical temperature and pressure, boiling points, dew points, heat transfer coefficients, deposit formation rates, and deposit removal. Three fuels were included in the experiments: Jet-A, an experimental referree broad specification fuel, and a premium No. 2 diesel fuel. Engine conditions representing a NASA Energy Efficient Engine at sea-level take-off, cruise, and idle were simulated in the vaporization system and it was found that single phase flow was maintained in the heat exchanger and downstream of the throttle. Deposits encountered in the heat exchanger represented a thermal resistance as high as 1300 sq M K/watt and a deposit formation rate over 1000 gC/sq cm hr.

  1. Experimental vaporization of the Holbrook chondrite (United States)

    Gooding, J. L.; Muenow, D. W.


    The vapor phase composition obtained by heating samples of the Holbrook L6 chondrite to 1300 C was determined quantitatively by Knudsen cell-quadrupole mass spectrometry. Maximum observed vapor pressures, produced at 1200 C, are reported for Na, K, Fe, and Ni, and the implications of the Na/K ratio are considered. The Fe and Ni data are discussed with attention to their migration in individual equilibrated chondrites. S2 (with minor SO2), H2O, and CO2 were also present in the high-temperature gas phase. Vesicles formed by the release of intrinsically derived volatiles are compared with vesicles in the Ibitira eucrite. Chondrite evolution is briefly discussed.

  2. Vaporization of fault water during seismic slip (United States)

    Chen, Jianye; Niemeijer, André R.; Fokker, Peter A.


    Laboratory and numerical studies, as well as field observations, indicate that phase transitions of pore water might be an important process in large earthquakes. We present a model of the thermo-hydro-chemo-mechanical processes, including a two-phase mixture model to incorporate the phase transitions of pore water, occurring during fast slip (i.e., a natural earthquake) in order to investigate the effects of vaporization on the coseismic slip. Using parameters from typical natural faults, our modeling shows that vaporization can indeed occur at the shallow depths of an earthquake, irrespective of the wide variability of the parameters involved (sliding velocity, friction coefficient, gouge permeability and porosity, and shear-induced dilatancy). Due to the fast kinetics, water vaporization can cause a rapid slip weakening even when the hydrological conditions of the fault zone are not favorable for thermal pressurization, e.g., when permeability is high. At the same time, the latent heat associated with the phase transition causes the temperature rise in the slip zone to be buffered. Our parametric analyses reveal that the amount of frictional work is the principal factor controlling the onset and activity of vaporization and that it can easily be achieved in earthquakes. Our study shows that coseismic pore fluid vaporization might have played important roles at shallow depths of large earthquakes by enhancing slip weakening and buffering the temperature rise. The combined effects may provide an alternative explanation for the fact that low-temperature anomalies were measured in the slip zones at shallow depths of large earthquakes.

  3. Estimation water vapor content using the mixing ratio method and validated with the ANFIS PWV model (United States)

    Suparta, W.; Alhasa, K. M.; Singh, M. S. J.


    This study reported the comparison between water vapor content, the surface meteorological data (pressure, temperature, and relative humidity), and precipitable water vapor (PWV) produced by PWV from adaptive neuro fuzzy inference system (ANFIS) for areas in the Universiti Kebangsaan Malaysia Bangi (UKMB) station. The water vapor content value was estimated with mixing ratio method and the surface meteorological data as the parameter inputs. The accuracy of water vapor content was validated with PWV from ANFIS PWV model for the period of 20-23 December 2016. The result showed that the water vapor content has a similar trend with the PWV which produced by ANFIS PWV model (r = 0.975 at the 99% confidence level). This indicates that the water vapor content that obtained with mixing ratio agreed very well with the ANFIS PWV model. In addition, this study also found, the pattern of water vapor content and PWV have more influenced by the relative humidity.

  4. Vaporization of comet nuclei - Light curves and life times (United States)

    Cowan, J. J.; Ahearn, M. F.


    The effects of vaporization from the nucleus of a comet are examined and it is shown that a latitude dependence of vaporization can explain the asymmetries in cometary light curves. An attempt is made to explain the observed variation in molecular production rates with heliocentric distance when employing CO2 and clathrate hydrate ice as cometary nuclei substances. The energy balance equation and the vapor pressure equations of water and CO2 are used in calculating the vaporization from a surface. Calculations were carried out from both dry-ice and water-ice nuclei, using a variety of different effective visual albedos, but primarily for a thermal infrared of 0 (emission). Attention is given to cometary lifetimes and light curves and it was determined that the asymmetry in light curves occurs (occasionally) as a 'seasonal' effect due to a variation in the angle between the comet's rotation axis and the sun-comet line.

  5. Continuous flow, explosives vapor generator and sensor chamber (United States)

    Collins, Greg E.; Giordano, Braden C.; Sivaprakasam, Vasanthi; Ananth, Ramagopal; Hammond, Mark; Merritt, Charles D.; Tucker, John E.; Malito, Michael; Eversole, Jay D.; Rose-Pehrsson, Susan


    A novel liquid injection vapor generator (LIVG) is demonstrated that is amenable to low vapor pressure explosives, 2,4,6-trinitrotoluene and hexahydro-1,3,5-trinitro-1,3,5-triazine. The LIVG operates in a continuous manner, providing a constant and stable vapor output over a period of days and whose concentration can be extended over as much as three orders of magnitude. In addition, a large test atmosphere chamber attached to the LIVG is described, which enables the generation of a stable test atmosphere with controllable humidity and temperature. The size of the chamber allows for the complete insertion of testing instruments or arrays of materials into a uniform test atmosphere, and various electrical feedthroughs, insertion ports, and sealed doors permit simple and effective access to the sample chamber and its vapor.

  6. Study of film boiling collapse behavior during vapor explosion

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Masahiro; Yamano, Norihiro; Sugimoto, Jun [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Abe, Yutaka; Adachi, Hiromichi; Kobayashi, Tomoyoshi


    Possible large scale vapor explosions are safety concern in nuclear power plants during severe accident. In order to identify the occurrence of the vapor explosion and to estimate the magnitude of the induced pressure pulse, it is necessary to investigate the triggering condition for the vapor explosion. As a first step of this study, scooping analysis was conducted with a simulation code based on thermal detonation model. It was found that the pressure at the collapse of film boiling much affects the trigger condition of vapor explosion. Based on this analytical results, basic experiments were conducted to clarify the collapse conditions of film boiling on a high temperature solid ball surface. Film boiling condition was established by flooding water onto a high temperature stainless steel ball heated by a high frequency induction heater. After the film boiling was established, the pressure pulse generated by a shock tube was applied to collapse the steam film on the ball surface. As the experimental boundary conditions, materials and size of the balls, magnitude of pressure pulse and initial temperature of the carbon and stainless steel balls were varied. The transients of pressure and surface temperature were measured. It was found that the surface temperature on the balls sharply decreased when the pressure wave passed through the film on balls. Based on the surface temperature behavior, the film boiling collapse pattern was found to be categorized into several types. Especially, the pattern for stainless steel ball was categorized into three types; no collapse, collapse and reestablishment after collapse. It was thus clarified that the film boiling collapse behavior was identified by initial conditions and that the pressure required to collapse film boiling strongly depended on the initial surface temperature. The present results will provide a useful information for the analysis of vapor explosions based on the thermal detonation model. (J.P.N.)

  7. Vaporization and combustion of fuel droplets at supercritical conditions (United States)

    Yang, Vigor


    Vaporization and combustion liquid-fuel droplets in both sub- and super-critical environments have been examined. The formulation is based on the complete conservation equations for both gas and liquid phases, and accommodates finite-rate chemical kinetics and a full treatment of liquid-vapor phase equilibrium at the droplet surface. The governing equations and the associated interface boundary conditions are solved numerically using a fully coupled, implicit scheme with the dual time-stepping integration technique. The model is capable of treating the entire droplet history, including the transition from the subcritical to the supercritical state. As a specific example, the combustion of n-pentane fuel droplets in air is studied for pressures of 5-140 atm. In addition, the dynamic responses of droplet vaporization and combustion to ambient-pressure oscillations are investigated. Results indicate that the droplet gasification and burning mechanisms depend greatly on the ambient pressure. In particular, a rapid enlargement of the vaporization and combustion responses occurs when the droplet surface reaches its critical point, mainly due to the strong variations of latent heat of vaporization and thermophysical properties at the critical state.

  8. Vaporization of graphite in the temperature range of 4000 to 4500 K (United States)

    Lundell, J. H.; Dickey, R. R.


    The vaporization of graphite under intense laser radiation is considered both theoretically and experimentally. Under intense radiation, the mass-loss rate can be high enough to cause the flow in the laser plume to be supersonic. It is shown that under these conditions the vaporization process is coupled to the plume gasdynamics and the mass-loss rate for graphite is 62% of the free vaporization rate. Experimental results are presented for surface temperatures from 3985 to 4555 K and mass-loss rates from 0.56 to 27.0 g per sq cm sec. The results are used to determine the vapor pressure of graphite in a pressure range of 2 to 11 atm, and the values are shown to be in agreement with the JANAF vapor pressure curve.

  9. In-situ measurements of atmospheric hydrofluorocarbons (HFCs and perfluorocarbons (PFCs at the Shangdianzi regional background station, China

    Directory of Open Access Journals (Sweden)

    B. Yao


    Full Text Available Atmospheric hydrofluorocarbons (HFCs and perfluorocarbons (PFCs were measured in-situ at the Shangdianzi (SDZ Global Atmosphere Watch (GAW regional background station, China, from May 2010 to May 2011. The time series for five HFCs and three PFCs showed occasionally high-concentration events while background conditions occurred for 36% (HFC-32 to 83% (PFC-218 of all measurements. The mean mixing ratios during background conditions were 24.5 ppt (parts per trillion, 10−12, molar for HFC-23, 5.86 ppt for HFC-32, 9.97 ppt for HFC-125, 66.0 ppt for HFC-134a, 9.77 ppt for HFC-152a, 79.1 ppt for CF4, 4.22 ppt for PFC-116, and 0.56 ppt for PFC-218. The background mixing ratios for the compounds at SDZ are consistent with those obtained at mid to high latitude sites in the Northern Hemisphere. North-easterly winds were associated with negative contributions to atmospheric HFC and PFC loadings (mixing ratio anomalies weighted by time associated with winds in a given sector, whereas south-westerly advection (urban sector showed positive loadings. Chinese emissions estimated by a tracer ratio method using carbon monoxide as tracer were 3.6 ± 3.2 kt yr−1 for HFC-23, 4.3 ± 3.6 kt yr−1 for HFC-32, 2.7 ± 2.3 kt yr−1 for HFC-125, 6.0 ± 5.6 kt yr−1 for HFC-134a, 2.0 ± 1.8 kt yr−1 for HFC-152a, 2.4 ± 2.1 kt yr−1 for CF4, 0.27 ± 0.26 kt yr−1 for PFC-116, and 0.061 ± 0.095 kt yr−1 for PFC-218. The lower HFC-23 emissions compared to earlier studies may be a result of the HFC-23 abatement measures taken as part of Clean Development Mechanism (CDM projects that started in 2005.

  10. Vapor spill pipe monitor (United States)

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


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

  11. Composition of Vapors Evolved from Military TNT as Influenced by Temperature, Solid Composition, Age, and Source (United States)


    Nor were significant amounts of mono-nitro toluenes detected in the headspace vapors, a result which is in agreement with * Since electron capture gas...Material Data. Franklin GNO Corp., January 1969. (i0) Lenchitz, C. and R.W. Veliclvr, Vapor pressure and heat of sublimation of three nitrotoluenes

  12. Methodology for Assessing a Boiling Liquid Expanding Vapor Explosion (BLEVE) Blast Potential (United States)

    Keddy, Chris P.


    Composite Vessels are now used to store a variety of fluids or gases including cryogenic fluids under pressure. Sudden failure of these vessels under certain conditions can lead to a potentially catastrophic vapor expansion if thermal control is not maintained prior to failure. This can lead to a "Boiling Liquid Expanding Vapor Explosion" or BLEVE.

  13. Interfacial instability of a condensing vapor bubble in a subcooled liquid (United States)

    Ueno, I.; Ando, J.; Koiwa, Y.; Saiki, T.; Kaneko, T.


    A special attention is paid to the condensing and collapsing processes of vapor bubble injected into a subcooled pool. We try to extract the vapor-liquid interaction by employing a vapor generator that supplies vapor to the subcooled pool through an orifice instead of using a immersed heating surface to realize vapor bubbles by boiling phenomenon. This system enables ones to detect a spatio-temporal behavior of a single bubble of superheated vapor exposed to a subcooled liquid. In the present study, vapor of water is injected through an orifice at constant flow rate to the subcooled pool of water at the designated degree of subcooling under the atmospheric pressure. The degree of subcooling of the pool is ranged from 0 K to 70 K, and the vapor temperature is kept constant at 101 ∘C. The behaviors of the injected vapor are captured by high-speed camera at frame rate up to 0.3 million frame per second (fps) to track the temporal variation of the vapor bubble shape. It is found that the abrupt collapse of the vapor bubble exposed to the subcooled pool takes place under the condition that the degree of subcooling is greater than around 30 K, and that the abrupt collapse always takes place accompanying the fine disturbances or instability emerged on the free surface. We then evaluate a temporal variation of the apparent `volume' of the bubble V under the assumption of the axisymmetric shape of the vapor bubble. It is also found that the instability emerges slightly after the volume of the vapor bubble reaches the maximum value. It is evaluated that the second derivative of the corresponding `radius' R of the vapor bubble is negative when the instability appears on the bubble surface, where R = 3√ 3V/4π. We also illustrate that the wave number of the instability on the liquid-vapor interface increases as the degree of subcooling.

  14. Micro-mechanism of vapor film collapse on high temperature particle surface

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Yutaka; Tochio, Daisuke [Dept. of Mechanical Systems Engineering, Yamagata Univ., Yonezawa, Yamagata (Japan)


    Thermal detonation model is proposed to describe vapor explosion. According to this model, vapor film on pre-mixed high temperature droplet surface is needed to be collapsed for the trigger of the vapor explosion. It is pointed out that the vapor film collapse behavior is significantly affected by the subcooling of low temperature liquid. However, the effect of subcooling on micro-mechanism of vapor film collapse behavior is not experimentally well identified. The objective of the present research is to experimentally investigate the effect of subcooling on micro-mechanism of film boiling collapse behavior. As the results, it is experimentally clarified that the vapor film collapse behavior in low subcool condition is qualitatively different from the vapor film collapse behavior in high subcooling condition. In high subcooling condition, instability of the vapor film dominates the vapor film collapse on the particle surface. On the other hand, micro-mechanism at the interface between vapor and liquid such as micro-jet is dominant in low subcool condition in case of vapor film collapse by pressure pulse. (author)

  15. Shoot water relations of mature black spruce families displaying a genotype × environment interaction in growth rate. III. Diurnal patterns as influenced by vapor pressure deficit and internal water status (United States)

    John E. Major; Kurt H. Johnsen


    Pressure­volume curves were constructed and shoot water potentials measured for +20-year-old black spruce (Picea mariana (Mill.) BSP) trees from four full-sib families growing on a moist site and a dry site at the Petawawa Research Forest, Ontario, to determine whether differences in diurnal water relations traits were related to productivity. To...

  16. Nuclear vapor thermal reactor propulsion technology

    Energy Technology Data Exchange (ETDEWEB)

    Maya, I.; Diaz, N.J.; Dugan, E.T.; Watanabe, Y. (Innovative Nuclear Space Power and Propulsion Institute, University of Florida, Gainesville, Florida 32611 (United States)); McClanahan, J.A.; Wen-Hsiung Tu; Carman, R.L. (Rocketdyne Division/Rockwell International Corporation, P.O. Box 7922, Canoga Park, California 91309-7922 (United States))


    The conceptual design of a nuclear rocket based on the vapor core reactor is presented. The Nuclear Vapor Thermal Rocket (NVTR) offers the potential for a specific impulse of 1000 to 1200 s at thrust-to-weight ratios of 1 to 2. The design is based on NERVA geometry and systems with the solid fuel replaced by uranium tetrafluoride (UF[sub 4]) vapor. The closed-loop core does not rely on hydrodynamic confinement of the fuel. The hydrogen propellant is separated from the UF[sub 4] fuel gas by graphite structure. The hydrogen is maintained at high pressure ([similar to]100 atm), and exits the core at 3,100 K to 3,500 K. Zirconium carbide and hafnium carbide coatings are used to protect the hot graphite from the hydrogen. The core is surrounded by beryllium oxide reflector. The nuclear reactor core has been integrated into a 75 klb engine design using an expander cycle and dual turbopumps. The NVTR offers the potential for an incremental technology development pathway to high performance gas core reactors. Since the fuel is readily available, it also offers advantages in the initial cost of development, as it will not require major expenditures for fuel development.

  17. Steady State Vapor Bubble in Pool Boiling. (United States)

    Zou, An; Chanana, Ashish; Agrawal, Amit; Wayner, Peter C; Maroo, Shalabh C


    Boiling, a dynamic and multiscale process, has been studied for several decades; however, a comprehensive understanding of the process is still lacking. The bubble ebullition cycle, which occurs over millisecond time-span, makes it extremely challenging to study near-surface interfacial characteristics of a single bubble. Here, we create a steady-state vapor bubble that can remain stable for hours in a pool of sub-cooled water using a femtosecond laser source. The stability of the bubble allows us to measure the contact-angle and perform in-situ imaging of the contact-line region and the microlayer, on hydrophilic and hydrophobic surfaces and in both degassed and regular (with dissolved air) water. The early growth stage of vapor bubble in degassed water shows a completely wetted bubble base with the microlayer, and the bubble does not depart from the surface due to reduced liquid pressure in the microlayer. Using experimental data and numerical simulations, we obtain permissible range of maximum heat transfer coefficient possible in nucleate boiling and the width of the evaporating layer in the contact-line region. This technique of creating and measuring fundamental characteristics of a stable vapor bubble will facilitate rational design of nanostructures for boiling enhancement and advance thermal management in electronics.

  18. Droplet vaporization in a supercritical microgravity environment (United States)

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

    A model has been developed for non-convective vaporization of liquid fuel droplets in an environment above the liquid critical pressure and near or above the liquid critical temperature. The model employs conservation of mass, energy and chemical species, along with transport properties which vary with temperature and species concentration. The liquid interface is assumed to be in thermodynamic equilibrium. The interface problem is solved using the Gibbs-Duhem relationship, and evaluating mixture fugacities using a modified Redlich-Kwong equation of state for the mixture. Due to the limited range of this equation, a curve-fit equation of state suitable for conditions far from the liquid critical point was applied. Results are presented for an n-octane liquid drop in nitrogen gas. For two gas conditions, several droplet sizes are modeled. Results include droplet size histories, surface temperature histories, and liquid and gas phase temperature profiles. The liquid vaporization rate is increased significantly for supercritical conditions compared to subcritical conditions. Using the specified equation of state for the ambient conditions tested, the droplet is completely vaporized before the liquid surface is heated to the liquid critical temperature.

  19. Modeling of vapor-liquid-liquid equilibria in binary mixtures

    NARCIS (Netherlands)

    Tzabar, Nir; ter Brake, Hermanus J.M.


    Vapor compression and Joule–Thomson (JT) cycles provide cooling power at the boiling temperatures of the refrigerants. Maintaining a fixed pressure in the evaporator allows for a stable cooling temperature at the boiling point of a pure refrigerant. In these coolers enhanced cooling power can be

  20. Collapsing criteria for vapor film around solid spheres as a fundamental stage leading to vapor explosion

    Energy Technology Data Exchange (ETDEWEB)

    Freud, Roy [Nuclear Research Center - Negev, Beer-Sheva (Israel)], E-mail:; Harari, Ronen [Nuclear Research Center - Negev, Beer-Sheva (Israel); Sher, Eran [Pearlstone Center for Aeronautical Studies, Department of Mechanical Engineering, Ben-Gurion University, Beer-Sheva (Israel)


    Following a partial fuel-melting accident, a Fuel-Coolant Interaction (FCI) can result with the fragmentation of the melt into tiny droplets. A vapor film is then formed between the melt fragments and the coolant, while preventing a contact between them. Triggering, propagation and expansion typically follow the premixing stage. In the triggering stage, vapor film collapse around one or several of the fragments occurs. This collapse can be the result of fragments cooling, a sort of mechanical force, or by any other means. When the vapor film collapses and the coolant re-establishes contact with the dry surface of the hot melt, it may lead to a very rapid and rather violent boiling. In the propagation stage the shock wave front leads to stripping of the films surrounding adjacent droplets which enhance the fragmentation and the process escalates. During this process a large quantity of liquid vaporizes and its expansion can result in destructive mechanical damage to the surrounding structures. This multiphase thermal detonation in which high pressure shock wave is formed is regarded as 'vapor explosion'. The film boiling and its possible collapse is a fundamental stage leading to vapor explosion. If the interaction of the melt and the coolant does not result in a film boiling, no explosion occurs. Many studies have been devoted to determine the minimum temperature and heat flux that is required to maintain a film boiling. The present experimental study examines the minimum temperature that is required to maintain a film boiling around metal spheres immersed into a liquid (subcooled distilled water) reservoir. In order to simulate fuel fragments that are small in dimension and has mirror-like surface, small spheres coated with anti-oxidation layer were used. The heat flux from the spheres was calculated from the sphere's temperature profiles and the sphere's properties. The vapor film collapse was associated with a sharp rise of the heat flux

  1. Student Exposure to Mercury Vapors. (United States)

    Weber, Joyce


    Discusses the problem of mercury vapors caused by spills in high school and college laboratories. Describes a study which compared the mercury vapor levels of laboratories in both an older and a newer building. Concludes that the mercurial contamination of chemistry laboratories presents minimal risks to the students. (TW)

  2. Quality and Control of Water Vapor Winds (United States)

    Jedlovec, Gary J.; Atkinson, Robert J.


    Water vapor imagery from the geostationary satellites such as GOES, Meteosat, and GMS provides synoptic views of dynamical events on a continual basis. Because the imagery represents a non-linear combination of mid- and upper-tropospheric thermodynamic parameters (three-dimensional variations in temperature and humidity), video loops of these image products provide enlightening views of regional flow fields, the movement of tropical and extratropical storm systems, the transfer of moisture between hemispheres and from the tropics to the mid- latitudes, and the dominance of high pressure systems over particular regions of the Earth. Despite the obvious larger scale features, the water vapor imagery contains significant image variability down to the single 8 km GOES pixel. These features can be quantitatively identified and tracked from one time to the next using various image processing techniques. Merrill et al. (1991), Hayden and Schmidt (1992), and Laurent (1993) have documented the operational procedures and capabilities of NOAA and ESOC to produce cloud and water vapor winds. These techniques employ standard correlation and template matching approaches to wind tracking and use qualitative and quantitative procedures to eliminate bad wind vectors from the wind data set. Techniques have also been developed to improve the quality of the operational winds though robust editing procedures (Hayden and Veldon 1991). These quality and control approaches have limitations, are often subjective, and constrain wind variability to be consistent with model derived wind fields. This paper describes research focused on the refinement of objective quality and control parameters for water vapor wind vector data sets. New quality and control measures are developed and employed to provide a more robust wind data set for climate analysis, data assimilation studies, as well as operational weather forecasting. The parameters are applicable to cloud-tracked winds as well with minor

  3. Metal vaporization from weld pools (United States)

    Block-Bolten, A.; Eagar, T. W.


    Experimental studies of alloy vaporization from aluminum and stainless steel weld pools have been made in order to test a vaporization model based on thermodynamic data and the kinetic theory of gases. It is shown that the model can correctly predict the dominant metal vapors that form but that the absolute rate of vaporization is not known due to insufficient knowledge of the surface temperature distribution and subsequent condensation of the vapor in the cooler regions of the metal. Values of the net evaporation rates for different alloys have been measured and are found to vary by two orders of magnitude. Estimated maximum weld pool temperatures based upon the model are in good agreement with previous experimental measurements of electron beam welds.

  4. A Citizen's Guide to Vapor Intrusion Mitigation (United States)

    This guide describes how vapor intrusion is the movement of chemical vapors from contaminated soil and groundwater into nearby buildings.Vapors primarily enter through openings in the building foundation or basement walls.

  5. Thermodynamic Analysis of Combined Vapor Compression and Vapor Absorption Refrigeration System

    Directory of Open Access Journals (Sweden)



    Full Text Available Two of the popular refrigeration cycles, VC (Vapor Compression, and VA (Vapor Absorption are used extensively for refrigeration purposes. In this paper, a system is proposed that works using both cycles powered by an IC (Internal Combustion engine, where mechanical energy is used to run the VC cycle while exhaust gasses are used to operate the VA cycle. The VC cycle works on R12 refrigerant while LiBr-H2O combination is selected for operation of VA cycle. Firstly, the refrigeration system is modeled, followed by a parametric study to investigate the impacts of various operating parameters on the system performance. The results exhibit that for maximum chilling and overall performance, the condenser and evaporator pressures in the VC cycle are obtained as 710 and 340 kPa, respectively, whereas generator and absorber temperatures in VA cycle are 85 and 20oC, respectively

  6. Using vapor phase tomography to measure the spatial distribution of vapor concentrations and flux for vadose-zone VOC sources. (United States)

    Mainhagu, J; Morrison, C; Brusseau, M L


    A test was conducted at a chlorinated-solvent contaminated site in Tucson, AZ, to evaluate the effectiveness of vapor-phase tomography (VPT) for characterizing the distribution of volatile organic contaminants (VOC) in the vadose zone. A soil vapor extraction (SVE) system has been in operation at the site since 2007. Vapor concentration and vacuum pressure were measured at four different depths in each of the four monitoring wells surrounding the extraction well. The test provided a 3D characterization of local vapor concentrations under induced-gradient conditions. Permeability data obtained from analysis of borehole logs were used along with pressure and the vapor-concentration data to determine VOC mass flux within the test domain. A region of higher mass flux was identified in the deepest interval of the S-SW section of the domain, indicating the possible location of a zone with greater contaminant mass. These results are consistent with the TCE-concentration distribution obtained from sediment coring conducted at the site. In contrast, the results of a standard soil gas survey did not indicate the presence of a zone with greater contaminant mass. These results indicate that the VPT test provided a robust characterization of VOC concentration and flux distribution at the site. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Atmospheric Hydrodeoxygenation of Biomass Fast Pyrolysis Vapor by MoO3

    DEFF Research Database (Denmark)

    Zhou, Guofeng; Jensen, Peter Arendt; Le, Duy Michael


    was not significant at temperatures below 400 °C. At 450 °C catalyst temperature and 93 vol % H2 concentration, the wood pyrolysis vapor was more active toward cracking forming gas species instead of performing the desired HDO forming hydrocarbons. The lignin pyrolysis vapor was more resistant to cracking and yielded......MoO3 has been tested as a catalyst in hydrodeoxygenation (HDO) of both model compounds (acetone and guaiacol) and real biomass pyrolysis vapors under atmospheric pressure. The pyrolysis vapor was obtained by fast pyrolysis of wood or lignin in a continuous fast pyrolysis reactor at a fixed...... temperature of 500 °C, and it subsequently passed through a downstream, close coupled, fixed bed reactor containing the MoO3 catalyst. The influences of the catalyst temperature and the concentration of H2 on the HDO of the pyrolysis vapors were investigated. The level of HDO of the biomass pyrolysis vapors...

  8. Assessment of Mitigation Systems on Vapor Intrusion: Temporal Trends, Attenuation Factors, and Contaminant Migration Routes under Mitigated and Non-mitigated Conditions (United States)

    Vapor intrusion is the migration of subsurface vapors, including radon and volatile organic compounds (VOCs), in soil gas from the subsurface to indoor air. Vapor intrusion happens because there are pressure and concentration differentials between indoor air and soil gas. Indoor ...

  9. Chemical Vapor Deposition of Turbine Thermal Barrier Coatings (United States)

    Haven, Victor E.


    Ceramic thermal barrier coatings extend the operating temperature range of actively cooled gas turbine components, therefore increasing thermal efficiency. Performance and lifetime of existing ceram ic coatings are limited by spallation during heating and cooling cycles. Spallation of the ceramic is a function of its microstructure, which is determined by the deposition method. This research is investigating metalorganic chemical vapor deposition (MOCVD) of yttria stabilized zirconia to improve performance and reduce costs relative to electron beam physical vapor deposition. Coatings are deposited in an induction-heated, low-pressure reactor at 10 microns per hour. The coating's composition, structure, and response to the turbine environment will be characterized.

  10. Growth of Carbon Nanostructure Materials Using Laser Vaporization (United States)

    Zhu, Shen; Su, Ching-Hua; Lehozeky, S.


    Since the potential applications of carbon nanotubes (CNT) was discovered in many fields, such as non-structure electronics, lightweight composite structure, and drug delivery, CNT has been grown by many techniques in which high yield single wall CNT has been produced by physical processes including arc vaporization and laser vaporization. In this presentation, the growth mechanism of the carbon nanostructure materials by laser vaporization is to be discussed. Carbon nanoparticles and nanotubes have been synthesized using pulsed laser vaporization on Si substrates in various temperatures and pressures. Two kinds of targets were used to grow the nanostructure materials. One was a pure graphite target and the other one contained Ni and Co catalysts. The growth temperatures were 600-1000 C and the pressures varied from several torr to 500 torr. Carbon nanoparticles were observed when a graphite target was used, although catalysts were deposited on substrates before growing carbon films. When the target contains catalysts, carbon nanotubes (CNT) are obtained. The CNT were characterized by scanning electron microscopy, x-ray diffraction, optical absorption and transmission, and Raman spectroscopy. The temperature-and pressure-dependencies of carbon nanotubes' growth rate and size were investigated.

  11. Acoustic droplet vaporization is initiated by superharmonic focusing

    NARCIS (Netherlands)

    Shpak, O.; Verweij, M.; Vos, H.J.; de Jong, N.; Lohse, Detlef; Versluis, Michel


    Acoustically sensitive emulsion droplets composed of a liquid perfluorocarbon have the potential to be a highly efficient system for local drug delivery, embolotherapy, or for tumor imaging. The physical mechanisms underlying the acoustic activation of these phase-change emulsions into a bubbly

  12. The interaction of the theophylline metastable phase with water vapor (United States)

    Matvienko, A. A.; Boldyrev, V. V.; Sidel'Nikov, A. A.; Chizhik, S. A.


    The conditions of hydration of the stable and metastable theophylline phases were determined. Two-phase metastable phase/monohydrate and stable phase/monohydrate equilibrium pressures were measured at 25, 30, and 35°C. The metastable phase began to react with water vapor at lower relative humidities than the stable phase. Processes that occurred with the metastable and stable theophylline phases over various water pressure ranges were considered. The metastable phase exhibited an unusual behavior at 25°C and relative humidity 47%. At constant water vapor pressure and temperature, theophylline was initially hydrated and then lost water and again became anhydrous. Two consecutive processes occurred in the system, the formation of theophylline monohydrate from the metastable phase and its decomposition to the stable phase. The ratio between the rates of these processes determined the content of the monohydrate at the given time moment.

  13. Digestibilidade do bagaço de cana-de-açúcar tratado com reagentes químicos e pressão de vapor Digestibility of sugar cane bagasse treated with chemical reagents and steam pressure

    Directory of Open Access Journals (Sweden)

    Ricardo Pereira Manzano


    Full Text Available Com o objetivo de elevar a digestibilidade do bagaço de cana-de-açúcar, este resíduo agro-industrial foi tratado com inúmeros reagentes químicos acompanhados ou não de tratamento físico. Após ensaios preliminares, nos quais diversos agentes deslignificantes foram avaliados, dez tratamentos foram selecionados para serem melhor estudados em ensaios de digestibilidade in vitro da matéria seca e da matéria orgânica. Em seguida, para o ensaio de digestibilidade in vivo, foram feitas quatro dietas à base de: 1 - Bagaço auto-hidrolisado (BAH, pressão de 17 kgf/cm² por 5 min; 2 - Bagaço tratado com 4% Na2S + 6% NaOH, pressão de 12 kgf/cm² por 8 min; 3 - Bagaço tratado com 2% Na2S + 3% NaOH, pressão de 12 kgf/cm² por 8 min; e 4 - Bagaço tratado com 9% H2O2 + 7% NaOH, a 70ºC por 8 min. Bagaço tratado com 4% Na2S + 6% NaOH e submetido a 12 kgf/cm² de pressão apresentou os melhores coeficientes de digestibilidade da matéria seca, matéria orgânica, fibra em detergente neutro e fibra em detergente ácido e o maior valor de nutrientes digestíveis totais. Em seguida, o bagaço tratado com 9% H2O2 + 7% NaOH a 70ºC por 8 min apresentou os melhores resultados. Piores resultados foram observados para o bagaço hidrolizado. A melhor digestibilidade de algumas das dietas, particularmente das frações fibrosas, sugere a exiqüibilidade do emprego de menores quantidades de alimento concentrado em dietas à base de bagaço de cana tratado química/fisicamente.In order to increase the sugar cane bagasse digestibility, this agricultural by-product was treated with several chemical reagents with or without physical treatment. After preliminary evaluation, where several delignificant agents were evaluated, ten treatments were selected for more detailed in vitro dry and organic matter disappearance trials. Then, for the in vivo digestibility trial, four sugar cane bagasse based diets were made: 1 - Hydrolyzed sugar cane bagasse, pressure of

  14. Understanding Latent Heat of Vaporization. (United States)

    Linz, Ed


    Presents a simple exercise for students to do in the kitchen at home to determine the latent heat of vaporization of water using typical household materials. Designed to stress understanding by sacrificing precision for simplicity. (JRH)

  15. Microenvironmental exposure to mercury vapor

    Energy Technology Data Exchange (ETDEWEB)

    Stopford, W.; Bundy, S.D.; Goldwater, L.J.; Bittikofer, J.A.


    Work area and breathing zone samples were collected in a factory utilizing metallic mercury and analyzed for mercury vapor content. Breathing zone samples averaged several fold higher in concentration than concurrent area samples, reflecting a ''microenvironmental'' exposure to mercury vapor, presumably from contaminated clothing and hands. Blood and corrected total urine mercury values correlated well with the average microenvironmental exposure level for each worker. Measurements of unbound mercury in urine samples were sensitive at picking up minimal exposures. Excessive amounts of unbound mercury were not found in the urine, even with wide day-to-day swings in microenvironmental mercury vapor levels, suggesting that the human body can adapt to a chronic, moderate exposure to mercury vapor.

  16. Combustion Experiment to Evaluate a LOX Vaporization Nozzle for a Swirling-Oxidizer-Flow-Type Hybrid Rocket Engine with a 1500N-Thrust (United States)

    Kitagawa, Koki; Sakurazawa, Toshiaki; Yuasa, Saburo

    The authors have proposed a LOX vaporization nozzle for swirling-oxidizer-flow-type hybrid rocket engines to increase engine performance. In this study, we developed the LOX vaporization nozzle for this type of a hybrid rocket engine with a 1500N-thrust. Vaporization experiments, using a LOX supply system for the nozzle to be independent of a GOX supply system for the engine, were conducted. The test runs at little oxygen mass flow rates and low combustion pressures at the design point showed that LOX could be vaporized safely through the nozzle. It was confirmed that the design of the LOX vaporization nozzle was proper. Vaporization and burning experiments using vaporized O2 through the LOX vaporization nozzle showed that reliable and rapid ignition and stable combustion without combustion oscillation were achieved. The LOX vaporization nozzle increased the engine performance of the swirling-oxidizer- flow-type hybrid rocket engine.

  17. On the vapor-liquid equilibrium in hydroprocessing reactors

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.; Munteanu, M.; Farooqi, H. [National Centre for Upgrading Technology, Devon, AB (Canada)


    When petroleum distillates undergo hydrotreating and hydrocracking, the feedstock and hydrogen pass through trickle-bed catalytic reactors at high temperatures and pressures with large hydrogen flow. As such, the oil is partially vaporized and the hydrogen is partially dissolved in liquid to form a vapor-liquid equilibrium (VLE) system with both vapor and liquid phases containing oil and hydrogen. This may result in considerable changes in flow rates, physical properties and chemical compositions of both phases. Flow dynamics, mass transfer, heat transfer and reaction kinetics may also be modified. Experimental observations of VLE behaviours in distillates with different feedstocks under a range of operating conditions were presented. In addition, VLE was predicted along with its effects on distillates in pilot and commercial scale plants. tabs., figs.

  18. Effect of sintering columns on the heat transfer and flow characteristics of the liquid cooling vapor chambers (United States)

    Naphon, Paisarn; Wiriyasart, Songkran


    The results of the heat and flow characteristics of working fluid inside the vapor chamber with different sintering columns of 20, 81, 225 are presented. The vapor chambers with one inlet port and four outlet ports are tested by using water as coolant. Parametric studies including different heat fluxes, number and size of wick columns, and flow rate of coolants on the cooling performance are considered. A three-dimensional heat and mass transfer model for vapor chamber with wick and without sintering plate and sintering columns are developed. The numerical simulation results show the velocity and pressure distribution of liquid and vapor phases of the working fluid inside the vapor chamber. It is found that the number of wick column have an important influence to the velocity and pressure phenomena of working fluid which results in thermal performance of vapor chamber. Reasonable agreement is obtained from the comparison between the measured data and the predicted results.

  19. Microstructure of vapor deposited coatings on curved substrates

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, Theron M.; Zhao, Hengbei; Wadley, Haydn N. G., E-mail: [Department of Materials Science and Engineering, University of Virginia, 395 McCormick Rd., P.O. Box 400745, Charlottesville, Virginia 22904 (United States)


    Thermal barrier coating systems consisting of a metallic bond coat and ceramic over layer are widely used to extend the life of gas turbine engine components. They are applied using either high-vacuum physical vapor deposition techniques in which vapor atoms rarely experience scattering collisions during propagation to a substrate, or by gas jet assisted (low-vacuum) vapor deposition techniques that utilize scattering from streamlines to enable non-line-of-sight deposition. Both approaches require substrate motion to coat a substrate of complex shape. Here, direct simulation Monte Carlo and kinetic Monte Carlo simulation methods are combined to simulate the deposition of a nickel coating over the concave and convex surfaces of a model airfoil, and the simulation results are compared with those from experimental depositions. The simulation method successfully predicted variations in coating thickness, columnar growth angle, and porosity during both stationary and substrate rotated deposition. It was then used to investigate a wide range of vapor deposition conditions spanning high-vacuum physical vapor deposition to low-vacuum gas jet assisted vapor deposition. The average coating thickness was found to increase initially with gas pressure reaching a maximum at a chamber pressure of 8–10 Pa, but the best coating thickness uniformity was achieved under high vacuum deposition conditions. However, high vacuum conditions increased the variation in the coatings pore volume fraction over the surface of the airfoil. The simulation approach was combined with an optimization algorithm and used to investigate novel deposition concepts to tailor the local coating thickness.


    Directory of Open Access Journals (Sweden)

    V. V. Ananskikh


    Full Text Available Starch hydrolysis is main technological process in production of starch sweeteners. Acid hydrolysis of starch using hydrochloric acid is carried out very fast but it does not allow to carry out full hydrolysis and to produce products with given carbohydrate composition. Bioconversion of starch allows to eliminate these limitations. At production of starch sweeteners from starch using enzymes starch hydrolysis is carried out in two stages At first starch – starch liquefaction the rapid increase of viscosity takes place which requires intensive mixing. Liquefying station consists of jet-cooker, holder, pressure regulator and evaporator. Jet-cooker of starch is its main part, starch is quickly turns into soluble (gelatinized state and it is partially liquefied by injection of starch suspension by flow of water vapor under pressure not less than 0,8 MPa. Heat and hydraulic calculation were carried out in order to determine constructive sizes of mixer for cooking of starch. The main hydraulic definable parameters are pressure drop in mixer, vapor pressure at mixer inlet, daily capacity of station by glucose syrup M, product consumption (starch suspension, diameter of inlet section of vapor nozzle. The goal of calculation was to determine vapor consumption M1, diameter d2 of outlet section of confuser injector, length l2 of gelatinization section. For heat calculation there was used Shukhov’s formula along with heat balance equation for gelatinization process. The numerical solution obtained with adopted assumptions given in applied mathematical package MATHCAD, for M = 50 t/day gives required daily vapor consumption M1 = 14,446 т. At hydraulic calculation of pressure drop in mixer there was used Bernoulli’s theorem. Solving obtained equations using MATHCAD found diameter of outlet section of consufer d2 = 0,023 м, vapor pressure inside of mixer p2 = 3,966·105 Па, l2 = 0,128 м. Developed method of calculation is used to determine


    Directory of Open Access Journals (Sweden)

    Zorana Arsenijević


    Full Text Available The widely used herbicide, dimethylamine salt of 2,4-dichlorophenoxy acetic acid (2,4-D-DMA, is usually prepared by mixing a dimethylamine (DMA aqueous solution with a solid 2,4-dichlorophenoxy acetic acid (2,4-D. The vapors of the both, reactants and products, are potentially hazardous for the environment. The contribution of DMA vapors in overall pollution from this process is most significant, concerning vapor pressures data of these pollutants. Therefore, the control of the air pollution in the manufacture and handling of methylamines is very important. Within this paper, the optimal air pollution control system in preparation of 2,4-D-DMA was developed for the pesticides manufacturing industry. This study employed the simple pollution prevention concept to reduce the emission of DMA vapors at the source. The investigations were performed on the pilot plant scale. To reduce the emission of DMA vapors, the effluent gases from the herbicide preparation zone were passed through the packed bed scrubber (water - scrubbing medium, and the catalytic reactor in sequence. The end result is a substantially improved air quality in the working area, as well as in the urbanized areas located near the chemical plant.

  2. Contrast-Enhanced Ultrasound Imaging and In Vivo Circulatory Kinetics with Low Boiling Point Nanoscale Phase-Change Perfluorocarbon Agents (United States)

    Sheeran, Paul S.; Rojas, Juan D.; Puett, Connor; Hjelmquist, Jordan; Arena, Christopher B.; Dayton, Paul A.


    Many studies have explored phase-change contrast agents (PCCAs) that can be vaporized by an ultrasonic pulse to form microbubbles for ultrasound imaging and therapy. However, few investigations have been published demonstrating the utility and characteristics of PCCAs as contrast agents in vivo. In this study, we examine the properties of low boiling point nanoscale PCCAs evaluated in vivo, and compare data to conventional microbubbles with respect to contrast generation and circulation properties. In order to do this, we develop a custom pulse sequence to vaporize and image PCCAs using the Verasonics research platform and a clinical array transducer. Results show that droplets can produce similar contrast enhancement to microbubbles (7.29 to 18.24 dB over baseline, depending on formulation), and can be designed to circulate for as much as 3.3 times longer than microbubbles. This study also demonstrates for the first time the ability to capture contrast wash-out kinetics of the target organ as a measure of vascular perfusion. PMID:25619781

  3. Vaporization behavior of non-stoichiometric refractory carbide materials and direct observations of the vapor phase using laser diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Butt, D.P.; Wantuck, P.J.; Rehse, S.J.; Wallace, T.C. Sr.


    Transition metal and actinide carbides, such as ZrC or NbC and UC or ThC, exhibit a wide range of stoichiometry, and therefore vaporize incongruently. At long times, steady state vaporization can be achieved where relative concentrations of atomic species on solid surface equals that in the gas phase. The surface composition under these steady state conditions is termed the congruently vaporizing composition, (CVC). Modeling the vaporization or corrosion behavior of this dynamic process is complex and requires an understanding of how the surface composition changes with time and a knowledge of CVC, which is both temperature and atmosphere dependent. This paper describes vaporization and corrosion behavior of non-stoichiometric refractory carbide materials and, as an example, describes a thermokinetic model that characterizes the vaporization behavior of the complex carbide U{sub x}Zr{sub 1-x}C{sub y} in hydrogen at 2500 to 3200 K. This model demonstrates that steady state corrosion of U{sub x}Zr{sub l-x}C{sub y} is rate limited by gaseous transport of Zr where partial pressure of Zr is determined by CVC. This paper also briefly describes efforts to image and characterize the vapor phase above the surface of ZrC in static and flowing gas environments using planar laser induced fluorescence. We have developed the method for monitoring and controlling the corrosion behavior of nuclear fuels in nuclear thermal rockets. However, the techniques described can be used, to image boundary layers, and could be used verifying corrosion models.


    Energy Technology Data Exchange (ETDEWEB)



    Revised for a more comprehensive overview of vapor incidents reported at the Hanford Tank Farms. Investigation into the meteorological influences on vapor incidents in the tank farm to determine what, if any, meteorological influences contribute to the reporting of odors, smells, vapors, and other gases. Weather phenomena, specifically barometric pressure, and wind velocity and direction can potentially cause or exacerbate a vapor release within the farm systems. The purpose of this document is to gather and evaluate the meteorological and weather information for the Tank Farms Shift Log Vapor Incident entries and determine what, if any, meteorological influences contribute to the reporting of odors, smells, vapors, and other gases such as propane. A part of the evaluation will be determining which of the incidents are related to actual ''intrusive'' work, and which are ''transient.'' Transient vapor incidents are herein defined as those vapors encountered during walkdowns, surveys, or other activities that did not require working directly with the tanks, pits, transfer lines, etc. Another part of the investigation will involve determining if there are barometric pressures or other weather related phenomena that might cause or contribute vapors being released when there are no ''intrusive'' activities. A final purpose is to evaluate whether there is any correlation between the 242-A Evaporator operations and Vapor Incidents entered on the Shift Log.

  5. Paramagnetic perfluorocarbon-filled albumin-(Gd-DTPA) microbubbles for the induction of focused-ultrasound-induced blood-brain barrier opening and concurrent MR and ultrasound imaging. (United States)

    Liao, Ai-Ho; Liu, Hao-Li; Su, Chia-Hao; Hua, Mu-Yi; Yang, Hung-Wei; Weng, Yu-Ting; Hsu, Po-Hung; Huang, Sheng-Min; Wu, Shih-Yen; Wang, Hsin-Ell; Yen, Tzu-Chen; Li, Pai-Chi


    This paper presents new albumin-shelled Gd-DTPA microbubbles (MBs) that can concurrently serve as a dual-modality contrast agent for ultrasound (US) imaging and magnetic resonance (MR) imaging to assist blood-brain barrier (BBB) opening and detect intracerebral hemorrhage (ICH) during focused ultrasound brain drug delivery. Perfluorocarbon-filled albumin-(Gd-DTPA) MBs were prepared with a mean diameter of 2320 nm and concentration of 2.903×10(9) MBs ml(-1) using albumin-(Gd-DTPA) and by sonication with perfluorocarbon (C(3)F(8)) gas. The albumin-(Gd-DTPA) MBs were then centrifuged and the procedure was repeated until the free Gd(3+) ions were eliminated (which were detected by the xylenol orange sodium salt solution). The albumin-(Gd-DTPA) MBs were also characterized and evaluated both in vitro and in vivo by US and MR imaging. Focused US was used with the albumin-(Gd-DTPA) MBs to induce disruption of the BBB in 18 rats. BBB disruption was confirmed with contrast-enhanced T(1)-weighted turbo-spin-echo sequence MR imaging. Heavy T(2)*-weighted 3D fast low-angle shot sequence MR imaging was used to detect ICH. In vitro US imaging experiments showed that albumin-(Gd-DTPA) MBs can significantly enhance the US contrast in T(1)-, T(2)- and T(2)*-weighted MR images. The r(1) and r(2) relaxivities for Gd-DTPA were 7.69 and 21.35 s(-1)mM(-1), respectively, indicating that the MBs represent a positive contrast agent in T(1)-weighted images. In vivo MR imaging experiments on 18 rats showed that focused US combined with albumin-(Gd-DTPA) MBs can be used to both induce disruption of the BBB and detect ICH. To compare the signal intensity change between pure BBB opening and BBB opening accompanying ICH, albumin-(Gd-DTPA) MB imaging can provide a ratio of 5.14 with significant difference (p = 0.026), whereas Gd-DTPA imaging only provides a ratio of 2.13 and without significant difference (p = 0.108). The results indicate that albumin-(Gd-DTPA) MBs have potential as a US/MR dual

  6. Acoustic droplet vaporization for diagnostic and therapeutic applications (United States)

    Kripfgans, Oliver Daniel

    A technology, termed Acoustic Droplet Vaporization (ADV), is developed whereby superheated droplets are caused to vaporize by application of an ultrasonic field. The droplet emulsion (90% pressure threshold exists above which the droplets vaporize into bubbles approximately 25-times the original droplet diameter. For frequencies between 1.5 and 8 MHz, the threshold decreases from 4.5 to 0.75 MPa peak rarefactional pressure. The single pulse efficiency of ADV has been measured as 26%. This technology might be useful for tissue occlusion in cancer treatment as well as for aberration correction in acoustic imaging. To demonstrate these potential applications, gas bubbles were made in vivo in animal models by ADV. It was found that ADV could be used to temporarily form large gas bubbles (>30 um) in vivo, which at large number density occluded targeted tissues and reduced the blood flow by 34%. Alternatively, for a very sparse droplet population, gas bubbles could serve as potential point beacons for phase aberration correction given their backscatter amplitudes of 24 dB above tissue background. Other possible applications include drug delivery, indicator for cryo therapy, pressure/radiation beacons, hyperthermia, and cavitation nuclei. ADV of individual droplets showed that during acoustic irradiation, droplets perform dipole-type oscillations and that such oscillations increased in amplitude with acoustic intensity. Smaller droplets required more acoustic intensity for vaporization than larger droplets; however, independent of droplet diameter, a maximum oscillation amplitude of 1.3 um, was required. This threshold corresponds to a Reynolds number of ˜5 x 104. Vaporization started either as a spot on the axis of oscillation close to a pole of the droplet, or homogeneously throughout the droplet's imaged cross-section. It is concluded that because of the high Reynolds number, the mechanism of vaporization might be based on hydrodynamic effects. An inverse frequency

  7. Effect of Interfacial Turbulence and Accommodation Coefficient on CFD Predictions of Pressurization and Pressure Control in Cryogenic Storage Tank (United States)

    Kassemi, Mohammad; Kartuzova, Olga; Hylton, Sonya


    Laminar models agree closely with the pressure evolution and vapor phase temperature stratification but under-predict liquid temperatures. Turbulent SST k-w and k-e models under-predict the pressurization rate and extent of stratification in the vapor but represent liquid temperature distributions fairly well. These conclusions seem to equally apply to large cryogenic tank simulations as well as small scale simulant fluid pressurization cases. Appropriate turbulent models that represent both interfacial and bulk vapor phase turbulence with greater fidelity are needed. Application of LES models to the tank pressurization problem can serve as a starting point.

  8. Half-sandwich cobalt complexes in the metal-organic chemical vapor deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Georgi, Colin [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany); Hapke, Marko; Thiel, Indre [Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT), Albert-Einstein-Straße 29a, Rostock 18059 (Germany); Hildebrandt, Alexander [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany); Waechtler, Thomas; Schulz, Stefan E. [Fraunhofer Institute of Electronic Nano Systems (ENAS), Technologie-Campus 3, Chemnitz 09126 (Germany); Technische Universität Chemnitz, Center for Microtechnologies (ZfM), Chemnitz 09107 (Germany); Lang, Heinrich, E-mail: [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany)


    A series of cobalt half-sandwich complexes of type [Co(η{sup 5}-C{sub 5}H{sub 5})(L)(L′)] (1: L, L′ = 1,5-hexadiene; 2: L = P(OEt){sub 3}, L′ = H{sub 2}C=CHSiMe{sub 3}; 3: L = L′ = P(OEt){sub 3}) has been studied regarding their physical properties such as the vapor pressure, decomposition temperature and applicability within the metal-organic chemical vapor deposition (MOCVD) process, with a focus of the influence of the phosphite ligands. It could be shown that an increasing number of P(OEt){sub 3} ligands increases the vapor pressure and thermal stability of the respective organometallic compound. Complex 3 appeared to be a promising MOCVD precursor with a high vapor pressure and hence was deposited onto Si/SiO{sub 2} (100 nm) substrates. The resulting reflective layer is closed, dense and homogeneous, with a slightly granulated surface morphology. X-ray photoelectron spectroscopy (XPS) studies demonstrated the formation of metallic cobalt, cobalt phosphate, cobalt oxide and cobalt carbide. - Highlights: • Thermal studies and vapor pressure measurements of cobalt half-sandwich complexes was carried out. • Chemical vapor deposition with cobalt half-sandwich complexes is reported. • The use of Co-phosphites results in significant phosphorous-doped metallic layers.

  9. Preconditioning of the YSZ-NiO Fuel Cell Anode in Hydrogenous Atmospheres Containing Water Vapor (United States)

    Vasyliv, Bogdan; Podhurska, Viktoriya; Ostash, Orest


    The YSZ-NiO ceramics for solid oxide fuel cells (SOFCs) anode have been investigated. A series of specimens were singly reduced in a hydrogenous atmosphere (Ar-5 vol% H2 mixture) at 600 °C under the pressure of 0.15 MPa or subjected to `reduction in the mixture-oxidation in air' (redox) cycling at 600 °C. The YSZ-Ni cermets formed in both treatment conditions were then aged in `water vapor in Ar-5 vol% H2 mixture' atmosphere at 600 °C under the pressure of 0.15 MPa. Additionally, the behaviour of the as-received material in this atmosphere was studied. It was revealed that small amount of water vapor in Ar-5 vol% H2 mixture (water vapor pressure below 0.03 MPa) does not affect the reduction of the nickel phase in the YSZ-NiO ceramics, but causes some changes in the YSZ-Ni cermet structure. In particular, nanopore growth in tiny Ni particles takes place. At higher concentration of water vapor in the mixture (water vapor pressure above 0.03-0.05 MPa), converse changes in the kinetics of reduction occur. The best physical and mechanical properties were revealed for the material treated by redox cycling after holding at 600 °C in water depleted gas mixture. The dual effect of water vapor on nickel-zirconia anode behaviour is discussed basing on scanning electron microscopy analysis data, material electrical conductivity, and strength.

  10. Rehabilitation and extension of the useful operating life of a high pressure casing of the 75 MW steam turbine of the thermoelectric power plant President Juarez in Rosarito, B.C.; Rehabilitacion y extension de vida util de una carcasa de alta presion de la turbina de vapor de 75 MW de la central termoelectrica Presidente Juarez en Rosarito, B.C.

    Energy Technology Data Exchange (ETDEWEB)

    Mazur C, Zdzislaw; Hernandez R, Alejandro; Luna R, Alberto [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Fernandez, Rafael; Nieblas, Enrique [Comision Federal de Electricidad, Rosarito, Baja California (Mexico)


    The effective operation of the steam turbines is important to the world industries, but as all machinery, it is necessary to constantly examine and give maintenance to this equipment with the purpose of producing better results. Yet, many steam turbines arrive at an operation period of 30 or 40 years, over their original design capacity. A factor like this, only augments the probabilities of future problems with the casings, such as: thermal fatigue fissures, deformation of the horizontal union and erosion problems in the low pressure housings. The deformation of the casing can affect its capacity to maintain aligned the stationary parts of the turbine, as a consequence, damages can appear in the fixed and rotary components by interference or friction. Also, the water induction can deform the casing to such a degree that, the alignment of the stationary parts is altered until it causes contact and friction between stationary and rotary parts. However, depending on the type and degree of the casing deformation, different methods of rehabilitation can be applied. The core goal is to recover the planarity of the union of the flanges, re-machining the plane of the flange of the upper and lower casing or, alternatively, to carry out a scraping by hand. [Spanish] El funcionamiento eficaz de las turbinas de vapor es importante para las industrias del mundo, pero como toda maquinaria, es necesario examinar y dar mantenimiento constantemente a este equipo con la finalidad de producir mejores resultados. Con todo, muchas turbinas de vapor llegan a un periodo de operacion de 30 o 40 anos, por encima de su capacidad de diseno original. Un factor como este, solo eleva las probabilidades de futuros problemas con las carcasas, tales como: fisuras por fatiga termica, deformacion de la union horizontal y problemas de erosion en las carcasas de baja presion. La deformacion de la carcasa puede afectar su capacidad para mantener alineadas las partes estacionarias de la turbina, como

  11. Stepwise Swelling of a Thin Film of Lamellae-Forming Poly(styrene-b-butadiene) in Cyclohexane Vapor

    DEFF Research Database (Denmark)

    Di, Zhenyu; Posselt, Dorthe; Smilgies, Detlef-M.


    We investigated the swelling of a thin film of lamellae-forming poly(styrene-b-butadiene) in cyclohexane vapor. The vapor pressure and thus the degree of swelling of the film are increased in a stepwise manner using a custom-built sample cell. The resulting structural changes during and after eac...

  12. Studies of the Effects of Perfluorocarbon Emulsions on Platelet Number and Function in Models of Critical Battlefield Injury (United States)


    Anesthesiology, 2Neurosurgery, 3Pharmacology and 4VCU-Jonson Center for Critical Care and Pulmonary Research School of Medicine , Virginia Commonwealth...pressure (CVP); Pulmonary arterial blood pressure (PAP); Cardiac output and arterial, venous blood gases . • A survival moderate stepwise hemorrhagic...sampling of blood for gases , biochemistry, and hematologic evaluation. Arterial blood was removed 3ml/kg/min until MAP below 40mmHg. Once MAP returned to

  13. Measurements of the vertical profile of water vapor abundance in the Martian atmosphere from Mars Observer (United States)

    Schofield, J. T.; Mccleese, Daniel J.


    An analysis is presented of the Pressure Modulator Infrared Radiometer (PMIRR) capabilities along with how the vertical profiles of water vapor will be obtained. The PMIRR will employ filter and pressure modulation radiometry using nine spectral channels, in both limb scanning and nadir sounding modes, to obtain daily, global maps of temperature, dust extinction, condensate extinction, and water vapor mixing ratio profiles as a function of pressure to half scale height or 5 km vertical resolution. Surface thermal properties will also be mapped, and the polar radiactive balance will be monitored.

  14. Growth Process Conditions of Tungsten Oxide Thin Films Using Hot-Wire Chemical Vapor Deposition

    NARCIS (Netherlands)

    Houweling, Z.S.|info:eu-repo/dai/nl/251874486; Geus, J.W.; de Jong, M.; Harks, P.P.R.M.L.; van der Werf, C.H.M.; Schropp, R.E.I.|info:eu-repo/dai/nl/072502584


    We report the growth conditions of nanostructured tungsten oxide (WO3−x) thin films using hot-wire chemical vapor deposition (HWCVD). Two tungsten filaments were resistively heated to various temperatures and exposed to an air flow at various subatmospheric pressures. The oxygen partial pressure was

  15. Study on vapor film collapse behavior on high temperature particle surface. 2. Effect of subcooling on micro-mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Yutaka [Yamagata University, Dept. of Mechanical Systems Engineering, Yonezawa, Yamagata (Japan); Tochio, Daisuke [Yamagata Univ. (Japan)


    Thermal detonation model is proposed to describe vapor explosion. According to this model, vapor film on pre-mixed high temperature droplet surface should be collapsed for the trigger of the vapor explosion. It is pointed out that the vapor film collapse behavior is significantly affected by the subcooling of low temperature liquid. However, the effect of subcooling on micro-mechanism of vapor film collapse behavior is not experimentally well identified. The objective of the present research is to experimentally investigate the effect of subcooling on micro-mechanism of film boiling collapse behavior. As the results, it is experimentally clarified that the vapor film collapse behavior in low subcool condition is qualitatively different from the vapor film collapse behavior in high subcool condition. In high subcool condition, instability of the vapor film dominates the vapor film collapse on the particle surface. On the other hand, micro-mechanism at the interface between vapor and liquid such as micro-jet is dominant in low subcool condition in case of vapor film collapse by pressure pulse. (author)

  16. Intra-arrest hypothermia: both cold liquid ventilation with perfluorocarbons and cold intravenous saline rapidly achieve hypothermia, but only cold liquid ventilation improves resumption of spontaneous circulation. (United States)

    Riter, Henry G; Brooks, Leonard A; Pretorius, Andrew M; Ackermann, Laynez W; Kerber, Richard E


    Rapid intra-arrest induction of hypothermia using total liquid ventilation (TLV) with cold perfluorocarbons improves resuscitation outcome from ventricular fibrillation (VF). Cold saline intravenous infusion during cardiopulmonary resuscitation (CPR) is a simpler method of inducing hypothermia. We compared these 2 methods of rapid hypothermia induction for cardiac resuscitation. Three groups of swine were studied: cold preoxygenated TLV (TLV, n=8), cold intravenous saline infusion (S, n=8), and control (C, n=8). VF was electrically induced. Beginning at 8 min of VF, TLV and S animals received 3 min of cold TLV or rapid cold saline infusion. After 11 min of VF, all groups received standard air ventilation and closed chest massage. Defibrillation was attempted after 3 min of CPR (14 min of VF). The end point was resumption of spontaneous circulation (ROSC). Pulmonary arterial (PA) temperature decreased after 1 min of CPR from 37.2 degrees C to 32.2 degrees C in S and from 37.1 degrees C to 34.8 degrees C in TLV (S or TLV vs. C pcold saline infusion and cold TLV, but ROSC was higher than control only in cold TLV animals, probably due to better CPP and pO(2). The method by which hypothermia is achieved influences ROSC.

  17. Diffusional mechanisms augment the fluorine MR relaxation in paramagnetic perfluorocarbon nanoparticles that provides a "relaxation switch" for detecting cellular endosomal activation. (United States)

    Hu, Lingzhi; Zhang, Lei; Chen, Junjie; Lanza, Gregory M; Wickline, Samuel A


    To develop a physical model for the (19)F relaxation enhancement in paramagnetic perfluorocarbon nanoparticles (PFC NP) and demonstrate its application in monitoring cellular endosomal functionality through a "(19)F relaxation switch" phenomenon. An explicit expression for (19)F longitudinal relaxation enhancement was derived analytically. Monte-Carlo simulation was performed to confirm the gadolinium-induced magnetic field inhomogeneity inside the PFC NP. Field-dependent T(1) measurements for three types of paramagnetic PFC NPs were carried out to validate the theoretical prediction. Based on the physical model, (19)F and (1)H relaxation properties of macrophage internalized paramagnetic PFC NPs were measured to evaluate the intracellular process of NPs by macrophages in vitro. The theoretical description was confirmed experimentally by field-dependent T(1) measurements. The shortening of (19)F T(1) was found to be attributed to the Brownian motion of PFC molecules inside the NP in conjunction with their ability to permeate into the lipid surfactant coating. A dramatic change of (19)F T(1) was observed upon endocytosis, revealing the transition from intact bound PFC NP to processed constituents. The proposed first-principle analysis of (19)F spins in paramagnetic PFC NP relates their structural parameters to the special MR relaxation features. The demonstrated "(19)F relaxation switch" phenomenon is potentially useful for monitoring cellular endosomal functionality. Copyright © 2011 Wiley-Liss, Inc.

  18. Highly enhanced optical properties of indocyanine green/perfluorocarbon nanoemulsions for efficient lymph node mapping using near-infrared and magnetic resonance imaging (United States)

    Bae, Pan Kee; Jung, Juyeon; Chung, Bong Hyun


    The near-infrared (NIR) fluorescence probe has better tissue penetration and lower autofluorescence. Indocyanine green (ICG) is an NIR organic dye for extensive biological application, and it has been clinically approved for human medical imaging and diagnosis. However, application of this dye is limited by its numerous disadvantageous properties in aqueous solution, including its concentration-dependent aggregation, poor aqueous stability in vitro, and low quantum yield. Its use in molecular imaging probes is limited because it loses fluorescence after binding to nonspecific plasma proteins, leading to rapid elimination from the body with a half-life of 2 - 4 min. In this study, the multifunctional perfluorocarbon (PFC)/ICG nanoemulsions were investigated with the aim of overcoming these limitations. The PFC/ICG nanoemulsions as a new type of delivery vehicle for contrast agents have both NIR optical imaging and 19 F-MR imaging moieties. These nanoemulsions exhibited less aggregation, increased fluorescence intensity, long-term stability, and physicochemical stability against external light and temperature compared to free aqueous ICG. Also, the PFC/ICG bimodal nanoemulsions allow excellent detection of lymph nodes in vivo through NIR optical imaging and 19 F-MR imaging. This result showed the suitability of the proposed nanoemulsions for non-invasive lymph node mapping as they enable long-time detection of lymph nodes.

  19. Nonlinear dynamics of a vapor bubble expanding in a superheated region of finite size

    Energy Technology Data Exchange (ETDEWEB)

    Annenkova, E. A., E-mail: [Physics Faculty, Moscow State University, Leninskie Gory, 119991 Moscow (Russian Federation); Kreider, W. [Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th St., Seattle, WA 98105 (United States); Sapozhnikov, O. A. [Physics Faculty, Moscow State University, Leninskie Gory, 119991 Moscow (Russian Federation); Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th St., Seattle, WA 98105 (United States)


    Growth of a vapor bubble in a superheated liquid is studied theoretically. Contrary to the typical situation of boiling, when bubbles grow in a uniformly heated liquid, here the superheated region is considered in the form of a millimeter-sized spherical hot spot. An initial micron-sized bubble is positioned at the hot spot center and a theoretical model is developed that is capable of studying bubble growth caused by vapor pressure inside the bubble and corresponding hydrodynamic and thermal processes in the surrounding liquid. Such a situation is relevant to the dynamics of vapor cavities that are created in soft biological tissue in the focal region of a high-intensity focused ultrasound beam with a shocked pressure waveform. Such beams are used in the recently proposed treatment called boiling histotripsy. Knowing the typical behavior of vapor cavities during boiling histotripsy could help to optimize the therapeutic procedure.

  20. Pore‐scale modeling of vapor transport in partially saturated capillary tube with variable area using chemical potential

    National Research Council Canada - National Science Library

    Addassi, Mouadh; Schreyer, Lynn; Johannesson, Björn; Lin, Hai


    .... We demonstrate that isothermal vapor transport can be accurately modeled without modeling the details of the contact angle, microscale temperature fluctuations, or pressure fluctuations using a modification of the Fick‐Jacobs equation...

  1. Simple Chemical Vapor Deposition Experiment (United States)

    Pedersen, Henrik


    Chemical vapor deposition (CVD) is a process commonly used for the synthesis of thin films for several important technological applications, for example, microelectronics, hard coatings, and smart windows. Unfortunately, the complexity and prohibitive cost of CVD equipment makes it seldom available for undergraduate chemistry students. Here, a…

  2. Expansion of the laser ablation vapor plume into a background gas: Part A, Analysis


    Wen, Sy-Bor; Mao, Xianglei; Greif, Ralph; Russo, Richard E.


    A study of the gas dynamics of the vapor plume generated during laser ablation was conducted including a counterpropagating internal shock wave. The density, pressure, and temperature distributions between the external shock wave front and the sample surface were determined by solving the integrated conservation equations of mass, momentum, and energy. The positions of the shock waves and the contact surface (boundary that separates the compressed ambient gas and the vapor plume) were ob...

  3. Vapor-Phase Stoichiometry and Heat Treatment of CdTe Starting Material for Physical Vapor Transport (United States)

    Su, Ching-Hua; Sha, Yi-Gao; Lehoczky, S. L.; Liu, Hao-Chieh; Fang, Rei; Brebrick, R. F.


    Six batches of CdTe, having total amounts of material from 99 to 203 g and gross mole fraction of Te, X(sub Te), 0.499954-0.500138, were synthesized from pure Cd and Te elements. The vapor-phase stoichiometry of the assynthesized CdTe batches was determined from the partial pressure of Te2, P(sub Te2) using an optical absorption technique. The measured vapor compositions at 870 C were Te-rich for all of the batches with partial pressure ratios of Cd to Te2, P(sub Cd)/P(sub Te2), ranging from 0.00742 to 1.92. After the heat treatment of baking under dynamic vacuum at 870 C for 8 min, the vapor-phase compositions moved toward that of the congruent sublimation, i.e. P(sub Cd)/P(sub Te2) = 2.0, with the measured P(sub Cd)/P(sub Te2) varying from 1.84 to 3.47. The partial pressure measurements on one of the heat-treated samples also showed that the sample remained close to the congruent sublimation condition over the temperature range 800-880 C.

  4. 46 CFR 108.457 - Pressure release. (United States)


    .... Each air tight or vapor tight space, such as a paint locker, that is protected by a CO2 system must have a means for releasing pressure that accumulates within the space if CO2 is discharged into the... 46 Shipping 4 2010-10-01 2010-10-01 false Pressure release. 108.457 Section 108.457 Shipping COAST...

  5. Water vaporization promotes coseismic fluid pressurization and buffers temperature rise

    NARCIS (Netherlands)

    Chen, Jianye|info:eu-repo/dai/nl/370819071; Niemeijer, André|info:eu-repo/dai/nl/370832132; Yao, Lu; Ma, Shengli


    We investigated the frictional properties of carbonate-rich gouge layers at a slip rate of 1.3 m/s, under dry and water-saturated conditions, while monitoring temperature at different locations on one of the gouge-host rock interfaces. All experiments showed a peak frictional strength of 0.4–0.7,

  6. Vapor Pressure of N,N’-Diisopropylcarbodiimide (DICDI) (United States)


    editorial assistance and to the ECBC librarians for their assistance in finding several references. iv Blank v CONTENTS 1. INTRODUCTION...temperature and is used extensively by the toxicology community, especially in reference to inhalation hazard testing. Volatility is calculated using

  7. 78 FR 42595 - Marine Vapor Control Systems (United States)


    ... clarified the location of the gas injection and mixing arrangement relative to the vapor processing unit or... Parts 35 and 39 Marine Vapor Control Systems; Final Rule #0;#0;Federal Register / Vol. 78 , No. 136... Parts 154, 155, and 156 46 CFR Parts 35 and 39 RIN 1625-AB37 Marine Vapor Control Systems AGENCY: Coast...

  8. Evaporation of urea at atmospheric pressure. (United States)

    Bernhard, Andreas M; Czekaj, Izabela; Elsener, Martin; Wokaun, Alexander; Kröcher, Oliver


    Aqueous urea solution is widely used as reducing agent in the selective catalytic reduction of NO(x) (SCR). Because reports of urea vapor at atmospheric pressure are rare, gaseous urea is usually neglected in computational models used for designing SCR systems. In this study, urea evaporation was investigated under flow reactor conditions, and a Fourier transform infrared (FTIR) spectrum of gaseous urea was recorded at atmospheric pressure for the first time. The spectrum was compared to literature data under vacuum conditions and with theoretical spectra of monomolecular and dimeric urea in the gas phase calculated with the density functional theory (DFT) method. Comparison of the spectra indicates that urea vapor is in the monomolecular form at atmospheric pressure. The measured vapor pressure of urea agrees with the thermodynamic data obtained under vacuum reported in the literature. Our results indicate that considering gaseous urea will improve the computational modeling of urea SCR systems.

  9. Combustion chamber and thermal vapor stream producing apparatus and method (United States)

    Sperry, John S.; Krajicek, Richard W.; Cradeur, Robert R.


    A new and improved method and apparatus for burning a hydrocarbon fuel for producing a high pressure thermal vapor stream comprising steam and combustion gases for injecting into a subterranean formation for the recovery of liquefiable minerals therefrom, wherein a high pressure combustion chamber having multiple refractory lined combustion zones of varying diameters is provided for burning a hydrocarbon fuel and pressurized air in predetermined ratios injected into the chamber for producing hot combustion gases essentially free of oxidizing components and solid carbonaceous particles. The combustion zones are formed by zones of increasing diameters up a final zone of decreasing diameter to provide expansion zones which cause turbulence through controlled thorough mixing of the air and fuel to facilitate complete combustion. The high pressure air and fuel is injected into the first of the multiple zones where ignition occurs with a portion of the air injected at or near the point of ignition to further provide turbulence and more complete combustion.

  10. Preliminary characterization of an expanding flow of siloxane vapor MDM (United States)

    Spinelli, A.; Cozzi, F.; Cammi, G.; Zocca, M.; Gaetani, P.; Dossena, V.; Guardone, A.


    The early experimental results on the characterization of expanding flows of siloxane vapor MDM (C8H24O2Si3, octamethyltrisiloxane) are presented. The measurements were performed on the Test Rig for Organic VApors (TROVA) at the CREA Laboratory of Politecnico di Milano. The TROVA test-rig was built in order to investigate the non-ideal compressible-fluid behavior of typical expanding flows occurring within organic Rankine cycles (ORC) turbine passages. The test rig implements a batch Rankine cycle where a planar converging-diverging nozzle replaces the turbine and represents a test section. Investigations related to both fields of non-ideal compressible-fluid dynamics fundamentals and turbomachinery are allowed. The nozzle can be operated with different working fluids and operating conditions aiming at measuring independently the pressure, the temperature and the velocity field and thus providing data to verify the thermo-fluid dynamic models adopted to predict the behavior of these flows. The limiting values of pressure and temperature are 50 bar and 400 °C respectively. The early measurements are performed along the nozzle axis, where an isentropic process is expected to occur. In particular, the results reported here refer to the nozzle operated in adapted conditions using the siloxane vapor MDM as working fluid in thermodynamic regions where mild to medium non-ideal compressible-fluid effects are present. Both total temperature and total pressure of the nozzle are measured upstream of the test section, while static pressure are measured along the nozzle axis. Schlieren visualizations are also carried out in order to complement the pressure measurement with information about the 2D density gradient field. The Laser Doppler Velocimetry technique is planned to be used in the future for velocity measurements. The measured flow field has also been interpreted by resorting to the quasi-one-dimensional theory and two dimensional CFD viscous calculation. In both cases

  11. Isobaric (vapor + liquid) equilibria of the binary system maleic anhydride and diethyl phthalate at p = (2.67, 5.33, and 8.00) kPa

    Energy Technology Data Exchange (ETDEWEB)

    Xu Wei [Department of Chemistry, Institute of Science, Tianjin University, Tianjin 300072 (China); Liu Zhihua [Department of Chemistry, Institute of Science, Tianjin University, Tianjin 300072 (China); Tian Yiling [Department of Chemistry, Institute of Science, Tianjin University, Tianjin 300072 (China)]. E-mail:; Zhu Rongjiao [Department of Chemistry, Institute of Science, Tianjin University, Tianjin 300072 (China)


    Saturated vapor pressures of pure diethyl phthalate were measured with the ebulliometer. And isobaric (vapor + liquid) equilibrium data for the binary system (maleic anhydride + diethyl phthalate) at p = (2.67, 5.33, and 8.00) kPa were determined using the ebulliometric method. The parameters of the NRTL model for the binary system were obtained by calculating equilibrium compositions of the liquid and vapor phase with the experimental equilibrium temperatures, pressures and feed compositions. Moreover (vapor + liquid) equilibrium data for the binary system were predicted by use of the UNIFAC model. Predicted results were compared with those from the ebulliometric method, and showed good agreement.

  12. Sub-microsecond vapor plume dynamics under different keyhole penetration regimes in deep penetration laser welding (United States)

    Chen, Xin; Pang, Shengyong; Shao, Xinyu; Wang, Chunming; Zhang, Xiaosi; Jiang, Ping; Xiao, Jianzhong


    It is well-known that distinct vapor plume dynamics occur during deep penetration laser welding under different keyhole penetration states. However, there is little knowledge about the physical characteristics of vapor plumes (velocity, pressure, flow patterns, etc) located inside transient keyholes of varying penetration regimes in laser welding. This lack of knowledge is primarily because mesoscale vapor plumes are highly dynamic and generally invisible. Based on a well-tested three-dimensional multiphase laser welding model, we conducted a computational study on vapor plume dynamics inside transient keyholes during the fiber laser welding of 304 austenite stainless steel as a function of keyhole penetration regimes. We observed three keyhole regimes of penetration: full penetration, partial penetration and no penetration. We then physically analyzed the vapor plumes in these regimes. We determined that the vapor plume velocities and pressures in all three regimes were uneven and oscillated following the dynamic keyhole with a characteristic timescale in sub-microseconds. Only when the keyhole approached the full penetration regime did vapor plumes begin to violently eject from the bottom of the keyhole opening, whereas in the partial penetration regime, even when the bottom part of the keyhole was open, most of the vapor plume ejected from the upper keyhole opening. This latter observation was similar to that in the no penetration mode. We studied the physical mechanism of this behavior by analyzing the keyhole temperature and vapor plume velocity distributions. We determined that the upward ejection of the vapor plume from the upper keyhole opening was the result of an uneven micro-meter scale boiling phenomenon of the transient keyhole governed by Fresnel absorptions dependent on the local inclination angle of the keyhole wall. Similarly, we determined that the ejection of the vapor plume from the bottom of the keyhole opening resulted from pressure

  13. Effects of Natural Environmental Changes on Soil-Vapor Extraction Rates

    Energy Technology Data Exchange (ETDEWEB)

    Martins, S; Gregory, S


    Remediation by soil-vapor extraction has been used for over a decade at Lawrence Livermore National Laboratory (LLNL). We have found that natural changes in environmental conditions affect the rate of soil-vapor extraction. Data on flow rate observations collected over this time are compared to in-situ measurements of several different environmental parameters (soil-gas pressure, soil-temperature, soil-moisture, Electrical Resistance Tomography (ERT), rainfall and barometric pressure). Environmental changes that lead to increased soil-moisture are associated with reduced soil-vapor extraction flow rates. We have found that the use of higher extraction vacuums combined with dual-phase extraction can help to increase pneumatic conductivity when vadose zone saturation is a problem. Daily changes in barometric pressure and soil-gas temperature were found to change flow rate measurements by as much as 10% over the course of a day.

  14. Safety assessment of in-vessel vapor explosion loads in next generation reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Kwang Hyun; Cho, Jong Rae; Choi, Byung Uk; Kim, Ki Yong; Lee, Kyung Jung [Korea Maritime University, Busan (Korea); Park, Ik Kyu [Seoul National University, Seoul (Korea)


    A safety assessment of the reactor vessel lower head integrity under in-vessel vapor explosion loads has been performed. The premixing and explosion calculations were performed using TRACER-II code. Using the calculated explosion pressures imposed on the lower head inner wall, strain calculations were performed using ANSYS code. The explosion analyses show that the explosion impulses are not altered significantly by the uncertain parameters of triggering location and time, fuel and vapor volume fractions in uniform premixture bounding calculations within the conservative ranges. Strain analyses using the calculated pressure loads on the lower head inner wall show that the vapor explosion-induced lower head failure is physically unreasonable. The static analysis using the conservative explosion-end pressure of 7,246 psia shows that the maximum equivalent strain is 4.3% at the bottom of lower head, which is less than the allowable threshold value of 11%. (author). 24 refs., 40 figs., 3 tabs.

  15. Facile synthesis of magnetite/perfluorocarbon co-loaded organic/inorganic hybrid vesicles for dual-modality ultrasound/magnetic resonance imaging and imaging-guided high-intensity focused ultrasound ablation. (United States)

    Niu, Dechao; Wang, Xia; Li, Yongsheng; Zheng, Yuanyi; Li, Faqi; Chen, Hangrong; Gu, Jinlou; Zhao, Wenru; Shi, Jianlin


    Multifunctional organic/inorganic hybrid nanovesicles, fabricated by a facile self-assembly/sol-gel approach, display a unique morphology (figure) and satisfactory stability under physiological conditions. By co-encapsulation of superparamagnetic magnetite nanoparticles and a liquid perfluorocarbon, the nanovesicles can be used not only as a dual-modality ultrasound/magnetic resonance contrast agent for accurate cancer diagnosis and monitoring, but also as a therapeutic enhancement agent for effective high-intensity focused ultrasound (HIFU) ablation. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. High temperature vapors science and technology

    CERN Document Server

    Hastie, John


    High Temperature Vapors: Science and Technology focuses on the relationship of the basic science of high-temperature vapors to some areas of discernible practical importance in modern science and technology. The major high-temperature problem areas selected for discussion include chemical vapor transport and deposition; the vapor phase aspects of corrosion, combustion, and energy systems; and extraterrestrial high-temperature species. This book is comprised of seven chapters and begins with an introduction to the nature of the high-temperature vapor state, the scope and literature of high-temp

  17. Recent advances in vapor intrusion site investigations. (United States)

    McHugh, Thomas; Loll, Per; Eklund, Bart


    Our understanding of vapor intrusion has evolved rapidly since the discovery of the first high profile vapor intrusion sites in the late 1990s and early 2000s. Research efforts and field investigations have improved our understanding of vapor intrusion processes including the role of preferential pathways and natural barriers to vapor intrusion. This review paper addresses recent developments in the regulatory framework and conceptual model for vapor intrusion. In addition, a number of innovative investigation methods are discussed. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Vaporization chambers and associated methods (United States)

    Turner, Terry D.; Wilding, Bruce M.; McKellar, Michael G.; Shunn, Lee P.


    A vaporization chamber may include at least one conduit and a shell. The at least one conduit may have an inlet at a first end, an outlet at a second end and a flow path therebetween. The shell may surround a portion of each conduit and define a chamber surrounding the portion of each conduit. Additionally, a plurality of discrete apertures may be positioned at longitudinal intervals in a wall of each conduit, each discrete aperture of the plurality of discrete apertures sized and configured to direct a jet of fluid into each conduit from the chamber. A liquid may be vaporized by directing a first fluid comprising a liquid into the inlet at the first end of each conduit, directing jets of a second fluid into each conduit from the chamber through discrete apertures in a wall of each conduit and transferring heat from the second fluid to the first fluid.

  19. Chemical vapor deposition of sialon (United States)

    Landingham, R.L.; Casey, A.W.

    A laminated composite and a method for forming the composite by chemical vapor deposition are described. The composite includes a layer of sialon and a material to which the layer is bonded. The method includes the steps of exposing a surface of the material to an ammonia containing atmosphere; heating the surface to at least about 1200/sup 0/C; and impinging a gas containing N/sub 2/, SiCl/sub 4/, and AlCl/sub 3/ on the surface.

  20. Importance Profiles for Water Vapor (United States)

    Mapes, Brian; Chandra, Arunchandra S.; Kuang, Zhiming; Zuidema, Paquita


    Motivated by the scientific desire to align observations with quantities of physical interest, we survey how scalar importance functions depend on vertically resolved water vapor. Definitions of importance begin from familiar examples of water mass I m and TOA clear-sky outgoing longwave flux I OLR, in order to establish notation and illustrate graphically how the sensitivity profile or "kernel" depends on whether specific humidity S, relative humidity R, or ln(R) are used as measures of vapor. Then, new results on the sensitivity of convective activity I con to vapor (with implied knock-on effects such as weather prediction skill) are presented. In radiative-convective equilibrium, organized (line-like) convection is much more sensitive to moisture than scattered isotropic convection, but it exists in a drier mean state. The lesson for natural convection may be that organized convection is less susceptible to dryness and can survive and propagate into regions unfavorable for disorganized convection. This counterintuitive interpretive conclusion, with respect to the narrow numerical result behind it, highlights the importance of clarity about what is held constant at what values in sensitivity or susceptibility kernels. Finally, the sensitivities of observable radiance signals I sig for passive remote sensing are considered. While the accuracy of R in the lower free troposphere is crucial for the physical importance scalars, this layer is unfortunately the most difficult to isolate with passive remote sensing: In high emissivity channels, water vapor signals come from too high in the atmosphere (for satellites) or too low (for surface radiometers), while low emissivity channels have poor altitude discrimination and (in the case of satellites) are contaminated by surface emissions. For these reasons, active ranging (LiDAR) is the preferred observing strategy.

  1. Importance Profiles for Water Vapor (United States)

    Mapes, Brian; Chandra, Arunchandra S.; Kuang, Zhiming; Zuidema, Paquita


    Motivated by the scientific desire to align observations with quantities of physical interest, we survey how scalar importance functions depend on vertically resolved water vapor. Definitions of importance begin from familiar examples of water mass I m and TOA clear-sky outgoing longwave flux I OLR, in order to establish notation and illustrate graphically how the sensitivity profile or "kernel" depends on whether specific humidity S, relative humidity R, or ln( R) are used as measures of vapor. Then, new results on the sensitivity of convective activity I con to vapor (with implied knock-on effects such as weather prediction skill) are presented. In radiative-convective equilibrium, organized (line-like) convection is much more sensitive to moisture than scattered isotropic convection, but it exists in a drier mean state. The lesson for natural convection may be that organized convection is less susceptible to dryness and can survive and propagate into regions unfavorable for disorganized convection. This counterintuitive interpretive conclusion, with respect to the narrow numerical result behind it, highlights the importance of clarity about what is held constant at what values in sensitivity or susceptibility kernels. Finally, the sensitivities of observable radiance signals I sig for passive remote sensing are considered. While the accuracy of R in the lower free troposphere is crucial for the physical importance scalars, this layer is unfortunately the most difficult to isolate with passive remote sensing: In high emissivity channels, water vapor signals come from too high in the atmosphere (for satellites) or too low (for surface radiometers), while low emissivity channels have poor altitude discrimination and (in the case of satellites) are contaminated by surface emissions. For these reasons, active ranging (LiDAR) is the preferred observing strategy.

  2. Alterations of alveolar type II cells and intraalveolar surfactant after bronchoalveolar lavage and perfluorocarbon ventilation. An electron microscopical and stereological study in the rat lung

    Directory of Open Access Journals (Sweden)

    Burkhardt Wolfram


    Full Text Available Abstract Background Repeated bronchoalveolar lavage (BAL has been used in animals to induce surfactant depletion and to study therapeutical interventions of subsequent respiratory insufficiency. Intratracheal administration of surface active agents such as perfluorocarbons (PFC can prevent the alveolar collapse in surfactant depleted lungs. However, it is not known how BAL or subsequent PFC administration affect the intracellular and intraalveolar surfactant pool. Methods Male wistar rats were surfactant depleted by BAL and treated for 1 hour by conventional mechanical ventilation (Lavaged-Gas, n = 5 or partial liquid ventilation with PF 5080 (Lavaged-PF5080, n = 5. For control, 10 healthy animals with gas (Healthy-Gas, n = 5 or PF5080 filled lungs (Healthy-PF5080, n = 5 were studied. A design-based stereological approach was used for quantification of lung parenchyma and the intracellular and intraalveolar surfactant pool at the light and electron microscopic level. Results Compared to Healthy-lungs, Lavaged-animals had more type II cells with lamellar bodies in the process of secretion and freshly secreted lamellar body-like surfactant forms in the alveoli. The fraction of alveolar epithelial surface area covered with surfactant and total intraalveolar surfactant content were significantly smaller in Lavaged-animals. Compared with Gas-filled lungs, both PF5080-groups had a significantly higher total lung volume, but no other differences. Conclusion After BAL-induced alveolar surfactant depletion the amount of intracellularly stored surfactant is about half as high as in healthy animals. In lavaged animals short time liquid ventilation with PF5080 did not alter intra- or extracellular surfactant content or subtype composition.

  3. Média diária do déficit de pressão de saturação do vapor d'água do ar e sua influência na vapotranspiração de referência pelo modelo de penman-monteith (FAO 56 em Piracicaba - SP Daily average of the saturation-vapor-pressure deficit of the air and its influence upon the reference evapotranspiration by penman-monteith model (FAO56 in Piracicaba, SP, Brazil

    Directory of Open Access Journals (Sweden)

    Gustavo B. Lyra


    Full Text Available Utilizando-se como padrão as medidas lisimétricas de um gramado, avaliaram-se os resultados de estimativas de ETo obtidas com Dar_méd oriundos de 14 métodos para seu cálculo. Tais comparações permitiram separar os métodos de cálculo de Dar_méd em três grupos, ou seja: um grupo resultou sempre em superestimativa de ETo; em outro, a tendência foi de sempre subestimar, e no último a tendência foi de superestimar valores baixos (The results of the evapotranspiration obtained with the Dair_avg proceeding from 14 methods were evaluated, by using the lysimetric measures of a sward. These comparisons allowed to separate the Dar_avg calculating methods into three groups: a group always resulted into an overestimate ETo; in other one always tended to underestimating the ETo; and in the last tended to overestimating the low values (<4.5 mm day-1, while underestimating the high values of ETo. No significant statistical differences were observed (t test; p <0.05 in ETo as a function of the Dair_avg methods, when using the hourly average of the temperature and/or the air relative humidity in relation to those determined with the average of the maximum and minimum values of these elements. Among the methods proposed by paper FAO56, just the one using the average relative humidity to calculate the actual pressure (e a showed a satisfactory estimate. The best estimates of ETo were obtained with the Dair_avg methods using the average of the air temperature in the determination of the saturation pressure (e s and the average of the relative humidity for the actual pressure (e a. The use of saturation-vapor-pressure deficit of the air at a single time (from 9 or 10 a.m. local as a representative of Dair_avg showed to be a satisfactory alternative in estimating the ETo under the climatic conditions of Piracicaba, SP, Brazil.

  4. Efficiency enhancement of the ocean thermal energy conversion system with a vapor–vapor ejector

    Directory of Open Access Journals (Sweden)

    Ho-Saeng Lee


    Full Text Available In this article, 20 kW ocean thermal energy conversion with a vapor–vapor ejector is newly proposed. As a vapor–vapor ejector is installed in the system, the pressure difference between the turbine inlet and outlet increases. Therefore, the amount of the working fluid required for the total turbine work of 20 kW is less than when no vapor–vapor ejector is installed. Therefore, installing a vapor–vapor ejector in the system decreases the evaporation capacity and the pump work. The performance analysis considered the outlet pressure of the high-stage turbine, the mass flow ratio of the working fluid at the outlet of a separator just after the high-stage turbine, and the nozzle diameters of the vapor–vapor ejector. As the outlet pressure of high-stage turbine becomes lower, the turbine gross power of high-stage turbine and system efficiency increase although lower outlet pressure of high-stage turbine results in lower ejector performance. Similarly, in terms of mass flow ratio, the highest system efficiency was shown at mass flow ratio of 0.4 at the outlet of a separator just after the high-stage turbine. On the other hand, the performance of the ejector at mass flow ratio of 0.5 at the outlet of a separator was largest. When the nozzle diameters of the vapor–vapor ejector are properly designed, the vapor–vapor ejector shows the highest performance. After the optimization of the operation parameters, system efficiency of the proposed ocean thermal energy conversion power cycle was 2.47%, relatively 15% higher than that of the basic ocean thermal energy conversion power cycle (2.2%.

  5. Processing of extraterrestrial materials by high temperature vacuum vaporization (United States)

    Grimley, R. T.; Lipschutz, M. E.


    It is noted that problems associated with the extraction and concentration of elements and commpounds important for the construction and operation of space habitats have received little attention. High temperature vacuum vaporization is considered a promising approach; this is a technique for which the space environment offers advantages in the form of low ambient pressures and temperatures and the possibility of sustained high temperatures via solar thermal energy. To establish and refine this new technology, experimental determinations must be made of the material release profiles as a function of temperature, of the release kinetics and chemical forms of material being transported, and of the various means of altering release kinetics. Trace element data determined by neutron activation analysis of meteorites heated to 1400 C in vacuum is summarized. The principal tool, high temperature spectrometry, is used to examine the vaporization thermodynamics and kinetics of major and minor elements from complex multicomponent extraterrestrial materials.

  6. Advancements in water vapor electrolysis technology. [for Space Station ECLSS (United States)

    Chullen, Cinda; Heppner, Dennis B.; Sudar, Martin


    The paper describes a technology development program whose goal is to develop water vapor electrolysis (WVE) hardware that can be used selectively as localized topping capability in areas of high metabolic activity without oversizing the central air revitalization system on long-duration manned space missions. The WVE will be used primarily to generate O2 for the crew cabin but also to provide partial humidity control by removing water vapor from the cabin atmosphere. The electrochemically based WVE interfaces with cabin air which is controlled in the following ranges: dry bulb temperature of 292 to 300 K; dew point temperature of 278 to 289 K; relative humidity of 25 to 75 percent; and pressure of 101 + or - 1.4 kPa. Design requirements, construction details, and results for both single-cell and multicell module testing are presented, and the preliminary sizing of a multiperson subsystem is discussed.

  7. Model analysis of mechanisms controlling pneumatic soil vapor extraction

    DEFF Research Database (Denmark)

    Høier, Camilla Kruse; Sonnenborg, Torben Obel; Jensen, Karsten Høgh


    The efficiency of traditional soil venting or soil vapor extraction (SVE) highly depends on the architecture of the subsurface because imposed advective air flow tends to bypass low-permeable contaminated areas. Pneumatic SVE is a technique developed to enhance remediation efficiency of heterogen......The efficiency of traditional soil venting or soil vapor extraction (SVE) highly depends on the architecture of the subsurface because imposed advective air flow tends to bypass low-permeable contaminated areas. Pneumatic SVE is a technique developed to enhance remediation efficiency...... of heterogeneous soils by enforcing large fluctuating pressure fronts through the contaminated area. Laboratory experiments have suggested that pneumatic SVE considerably improves the recovery rate from low-permeable units. We have analyzed the experimental results using a numerical code and quantified...... level the pneumatic venting technology is superior to the traditional technique, and that the method is particularly efficient in cases where large permeability contrasts exist between soil units in the subsurface....

  8. Micropatterned charge heterogeneities via vapor deposition of aminosilanes. (United States)

    Pick, Christian; Argento, Christopher; Drazer, German; Frechette, Joelle


    Aminosilanes are routinely employed for charge reversal or to create coupling layers on oxide surfaces. We present a chemical vapor deposition method to pattern mica surfaces with regions of high-quality aminosilane (3-aminopropyltriethoxysilane, APTES) monolayers. The approach relies on the vapor deposition of an aminosilane through a patterned array of through-holes in a PDMS (poly(dimethylsiloxane)) membrane that acts as a mask. In aqueous solutions the surfaces have regular patterns of charge heterogeneities with minimal topographical variations over large areas. This versatile dry lift-off deposition method alleviates issues with multilayer formation and can be used to create charge patterns on curved surfaces. We identify the necessary steps to achieve high quality monolayers and charge reversal of the underlying mica surface: (1) hexane extraction to remove unreacted PDMS oligomers from the membrane that would otherwise deposit on and contaminate the substrate, (2) oxygen plasma treatment of the top of the membrane surfaces to generate a barrier layer that blocks APTES transport through the PDMS, and (3) low of the vapor pressure of APTES during deposition to minimize APTES condensation at the mica-membrane-vapor contact lines and to prevent multilayer formation. Under these conditions, AFM imaging shows that the monolayers have a height of 0.9 ± 0.2 nm with an increase in height up to 3 nm at the mica-membrane-vapor contact lines. Fluorescence imaging demonstrates pattern fidelity on both flat and curved surfaces, for feature sizes that vary between 6.5 and 40 μm. We verify charge reversal by measuring the double layer forces between a homogeneous (unpatterned) APTES monolayers and a mica surface in aqueous solution, and we characterize the surface potential of APTES monolayers by measuring the double-layer forces between identical APTES surfaces. We obtain a surface potential of +110 ± 6 mV at pH 4.0.

  9. Diurnal variations in water vapor over Central and South America (United States)

    Meza, Amalia; Mendoza, Luciano; Bianchi, Clara


    Diurnal variations in atmospheric integrated water vapor (IWV) are studied employing IWV estimates, with a 30 minutes sampling rate, derived from Global Navigation Satellite Systems (GNSS) observations during the period 2007-2013. The analysis was performed in 73 GNSS tracking sites (GPS + GLONASS) which have more than 5 years of data. The selected area involves different climate types, from polar to tropical, with different diurnal variations of the integrated total humidity content. There are many processes that could induce diurnal variations in atmospheric water vapor (Dai et al, 1999 a,b), the most relevant causes are: surface evapotranspiration, atmospheric large-scale vertical motion, atmospheric low-level moisture convergence and precipitation and vertical mixing (which affects the vertical distribution of water vapor but does not affect the IWV). The numerical tools, Singular Value Decomposition and classical Multidimensional Scaling methods, are used to study these variations, considering the measurements made at each stations, as sample in the analysis. The aim of this investigation is to identify the IWV variability with respect to the local time associated to the different climate regions. In order to improve our analysis, all available weather information, such as radiosondes measurements (which are few), measurements of pressure and temperature and Numerical Weather Models reanalysis data, are used. Reference: Dai, A., K. E. Trenberth, and T. R. Karl, 1999 a: Effects of clouds, soil moisture, precipitation and water vapor on diurnal temperature range. J. Climate, 12, 2451-2473. Dai, A., F. Giorgi, and K. E. Trenberth, 1999 b: Observed and model simulated precipitation diurnal cycle over the contiguous United States.J. Geophys. Res., 104, 6377-6402. KEYWORDS: water vapor, diurnal cycle, GNSS

  10. Quantifying activation of perfluorocarbon-based phase-change contrast agents using simultaneous acoustic and optical observation. (United States)

    Li, Sinan; Lin, Shengtao; Cheng, Yi; Matsunaga, Terry O; Eckersley, Robert J; Tang, Meng-Xing


    Phase-change contrast agents in the form of nanoscale droplets can be activated into microbubbles by ultrasound, extending the contrast beyond the vasculature. This article describes simultaneous optical and acoustical measurements for quantifying the ultrasound activation of phase-change contrast agents over a range of concentrations. In experiments, decafluorobutane-based nanodroplets of different dilutions were sonicated with a high-pressure activation pulse and two low-pressure interrogation pulses immediately before and after the activation pulse. The differences between the pre- and post-interrogation signals were calculated to quantify the acoustic power scattered by the microbubbles activated over a range of droplet concentrations. Optical observation occurred simultaneously with the acoustic measurement, and the pre- and post-microscopy images were processed to generate an independent quantitative indicator of the activated microbubble concentration. Both optical and acoustic measurements revealed linear relationships to the droplet concentration at a low concentration range <10(8)/mL when measured at body temperature. Further increases in droplet concentration resulted in saturation of the acoustic interrogation signal. Compared with body temperature, room temperature was found to produce much fewer and larger bubbles after ultrasound droplet activation. Copyright © 2015. Published by Elsevier Inc.

  11. Vaporization thermodynamics of K2S and K2SO3 (United States)

    Bennet, J. E.


    The vaporization reactions, vapor pressures, and thermodynamics of potassium sulfide and potassium sulfite were studied for purposes of providing fundamental data for the seed cycle in magnetohydrodynamic electric power generation. Rate of effusion studies, supported by tube furnace experiments, X-ray powder diffraction, mass spectrometry and appropriate chemical analyses and tests, revealed that potassium sulfite disproportionates at high temperatures to form potassium sulfide and potassium sulfate. Potassium sulfide was observed to vaporize incongruently, the initial vapors beng predominantly potassium atoms, with minor species being S2 and various K-S molecules. The ratio of K/S2 in the vapor is very large initially and decreases steadily with prolonged heating. Several materials were evaluated for purposes of containing K2S/K2SO3 at temperatures or = 800 C: Pt, Mo, W, quartz, machinable glass, BN, high density graphite, pyrolytic coated graphite, and alumina. Of these, only alumina was observed to be chemically inert to both K2S but reacted with K2SO3. The other materials were not suitable for either substance. Thermodynamic calculations based on measured vapor pressures and approximate free energy functions are described. Results from isothermal total mass loss experiments and from thermogravimetric experiments are also included.

  12. The Annual Cycle of Water Vapor on Mars as Observed by the Thermal Emission Spectrometer (United States)

    Smith, Michael D.; Vondrak, Richard R. (Technical Monitor)


    Spectra taken by the Mars Global Surveyor Thermal Emission Spectrometer (TES) have been used to monitor the latitude, longitude, and seasonal dependence of water vapor for over one full Martian year (March 1999-March 2001). A maximum in water vapor abundance is observed at high latitudes during mid-summer in both hemispheres, reaching a maximum value of approximately 100 pr-micrometer in the north and approximately 50 pr-micrometer in the south. Low water vapor abundance (water vapor. The latitudinal and seasonal dependence of the decay of the northern summer water vapor maximum implies cross-equatorial transport of water to the southern hemisphere, while there is little or no corresponding transport during the decay of the southern hemisphere summer maximum. The latitude-longitude dependence of annually-averaged water vapor (corrected for topography) has a significant positive correlation with albedo and significant negative correlations with thermal inertia and surface pressure. Comparison of TES results with those retrieved from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) experiments shows some similar features, but also many significant differences. The southern hemisphere maximum observed by TES was not observed by MAWD and the large latitudinal gradient in annually-averaged water vapor observed by MAWD does not appear in the TES results.

  13. Interfacial Dynamics of Condensing Vapor Bubbles in an Ultrasonic Acoustic Field (United States)

    Boziuk, Thomas; Smith, Marc; Glezer, Ari


    Enhancement of vapor condensation in quiescent subcooled liquid using ultrasonic actuation is investigated experimentally. The vapor bubbles are formed by direct injection from a pressurized steam reservoir through nozzles of varying characteristic diameters, and are advected within an acoustic field of programmable intensity. While kHz-range acoustic actuation typically couples to capillary instability of the vapor-liquid interface, ultrasonic (MHz-range) actuation leads to the formation of a liquid spout that penetrates into the vapor bubble and significantly increases its surface area and therefore condensation rate. Focusing of the ultrasonic beam along the spout leads to ejection of small-scale droplets from that are propelled towards the vapor liquid interface and result in localized acceleration of the condensation. High-speed video of Schlieren images is used to investigate the effects of the ultrasonic actuation on the thermal boundary layer on the liquid side of the vapor-liquid interface and its effect on the condensation rate, and the liquid motion during condensation is investigated using high-magnification PIV measurements. High-speed image processing is used to assess the effect of the actuation on the dynamics and temporal variation in characteristic scale (and condensation rate) of the vapor bubbles.

  14. Boiling point of volatile liquids at various pressures

    National Research Council Canada - National Science Library

    Luisa Maria Valencia; Cristhian Andres Aguirre-Tellez


    .... In response to this phenomenon, an investigation on the coexistence of both gas and liquid phases of a volatile substance in a closed system was made, establishing vapor pressure as the determining...

  15. Nanostructure Fabrication by Electron-Beam-Induced Deposition with Metal Carbonyl Precursor and Water Vapor (United States)

    Takeguchi, Masaki; Shimojo, Masayuki; Furuya, Kazuo


    Nanorod fabrication is performed by electron beam induced deposition (EBID) with iron carbonyl [Fe(CO)5] and tungsten carbonyl [W(CO)6] precursors. The effects of water vapor addition to each metal carbonyl on the microstructure and composition of the obtained nanorods are studied. Normally, EBID-fabricated metal nanorods consist of an amorphous phase containing a considerable amount of carbon. However, it is found that water vapor addition to iron carbonyl can effectively reduce the carbon content of the nanorods and induce the formation of carbon-free crystalline Fe3O4 nanorods with increasing partial pressure ratio of water vapor to iron carbonyl. In contrast, for tungsten carbonyl, water vapor addition has no obvious effect on carbon content reduction. The obtained nanorods consist of a carbon-rich amorphous matrix containing tungsten oxide nanocrystals inside.

  16. Fabrication and characterization of gelatin-based test materials for verification of trace contraband vapor detectors. (United States)

    Staymates, Jessica L; Gillen, Greg


    This work describes a method to produce inexpensive and field deployable test materials that can be used to verify the performance of trace contraband vapor detection systems such as ion mobility spectrometers (IMS) currently deployed worldwide for explosives, narcotics, and chemical warfare agent (CWA) detection. Requirements for such field deployable test materials include long shelf life, portability, and low manufacturing costs. Reported here is a method for fabricating these test materials using encapsulation of high vapor pressure compounds, such as methyl salicylate (MS), into a gelatin matrix. Gelatin serves as a diffusion barrier allowing for controlled and sustained release of test vapors. Test materials were prepared by incorporating serial dilutions of MS into gelatin, which provide controlled analyte vapor release over 3 to 4 orders of magnitude of instrument response. The test materials are simple to prepare and have been shown to be stable for at least one year under controlled laboratory conditions.

  17. Effects of additional vapors on sterilization of microorganism spores with plasma-excited neutral gas (United States)

    Matsui, Kei; Ikenaga, Noriaki; Sakudo, Noriyuki


    Some fundamental experiments are carried out in order to develop a plasma process that will uniformly sterilize both the space and inner wall of the reactor chamber at atmospheric pressure. Air, oxygen, argon, and nitrogen are each used as the plasma source gas to which mixed vapors of water and ethanol at different ratios are added. The reactor chamber is remotely located from the plasma area and a metal mesh for eliminating charged particles is installed between them. Thus, only reactive neutral particles such as plasma-excited gas molecules and radicals are utilized. As a result, adding vapors to the source gas markedly enhances the sterilization effect. In particular, air with water and/or ethanol vapor and oxygen with ethanol vapor show more than 6-log reduction for Geobacillus stearothermophilus spores.

  18. Vapor-deposited porous films for energy conversion (United States)

    Jankowski, Alan F.; Hayes, Jeffrey P.; Morse, Jeffrey D.


    Metallic films are grown with a "spongelike" morphology in the as-deposited condition using planar magnetron sputtering. The morphology of the deposit is characterized by metallic continuity in three dimensions with continuous and open porosity on the submicron scale. The stabilization of the spongelike morphology is found over a limited range of the sputter deposition parameters, that is, of working gas pressure and substrate temperature. This spongelike morphology is an extension of the features as generally represented in the classic zone models of growth for physical vapor deposits. Nickel coatings were deposited with working gas pressures up 4 Pa and for substrate temperatures up to 1000 K. The morphology of the deposits is examined in plan and in cross section views with scanning electron microscopy (SEM). The parametric range of gas pressure and substrate temperature (relative to absolute melt point) under which the spongelike metal deposits are produced appear universal for other metals including gold, silver, and aluminum.

  19. Pressure-Sensitive Paint Data on the Facility Aerodynamics Validation and Research (FAVOR) Model at AEDC (United States)


    and off-body data were acquired. These included pressure-sensitive paint (PSP), background oriented schlieren (BOS), laser vapor screen, and planar...on- and off-body data were acquired. These included pressure- sensitive paint (PSP), background oriented schlieren (BOS), laser vapor screen, and

  20. Boiling point of volatile liquids at various pressures

    Directory of Open Access Journals (Sweden)

    Luisa Maria Valencia


    Full Text Available Water, under normal conditions, tends to boil at a “normal boiling temperature” at which the atmospheric pressure fixes the average amount of kinetic energy needed to reach its boiling point. Yet, the normal boiling temperature of different substances varies depending on their nature, for which substances like alcohols, known as volatile, boil faster than water under same conditions. In response to this phenomenon, an investigation on the coexistence of both gas and liquid phases of a volatile substance in a closed system was made, establishing vapor pressure as the determining tendency of a substance to vaporize, which increases exponentially with temperature until a critical point is reached. Since atmospheric pressure is fixed, the internal pressure of the system was varied to determine its relationship with vapor pressure and thus with the boiling point of the substance, concluding that the internal pressure and boiling point of a volatile liquid in a closed system are negatively proportional.

  1. A photothermal model of selective photothermolysis with dynamically changing vaporization temperature. (United States)

    Zhang, Ji Zhuang; Zhang, Xue Xue; Audette, Michel


    The theory of selective photothermolysis (SP) is used in many fields of laser surgery and medicine. As several parameters and a number of complicated photothermal interactions are involved in SP, numerical simulations have been providing an important and effective way in SP studies. However, with different photothermal models of SP, simulated results differ considerably. In addition, insufficient attention has been paid to tissue pressure variation during SP in these models, so that vessel rupture and other clinical phenomena cannot be explained. A novel photothermal model of SP was proposed using a Monte Carlo method to simulate the laser transport in the tissue, a heat transfer equation with dynamically changing vaporization temperature to calculate the temperature distribution, and the Arrhenius equation to predict the thermal damage. A factor of trapped vaporized tissue water k was introduced to describe the effects on tissue pressure, temperature, and other related parameters. It was shown that the simulation results are affected significantly by k. Temperature and thermal damage volume are almost identical, respectively, to those obtained with models with vaporization at 100°C and models without vaporization when k = 0 and 1, while thermal damage volume is close to that obtained with models of vaporization at 110°C and 130°C, respectively, when k = 0.022 and k = 0.18. To some extent, the current models without vaporization and models with vaporization at constant temperature can be regarded as special cases at specific situations of this new photothermal model of SP. In addition, more descriptive simulation results, such as temperature, thermal damage, and pressure, are accessible with this model, although the accuracy depends on the value of k, the estimation of which is planned as future work.

  2. Vaporization of trace element species from coal under gasification and combustion conditions: Final report

    Energy Technology Data Exchange (ETDEWEB)



    The objective of this project was to establish the chemical forms and relative abundance of trace inorganic vapor species in coal during combustion and gasification. A joint experimental and calculational program to observe the vaporization of Illinois No. 6 bituminous and Wyodak subbituminous was performed. Experimental studies were performed by Knudsen cell mass spectroscopy on samples of each coal that were ashed at low temperature by an oxygen plasma. To simulate actual coal more closely, some samples were only partially ashed to retain more of the original organic components. Vapor species were identified and their abundances measured over the temperature range 300-1700 K. In the first year of the program, vaporization from the coal ash alone was studied. Dynamic partial pressures were measured against temperature and time. Vapor species of 32 major or trace elements were identified. During the second year of the program, mass spectrometry experiments addressed the effects of added gases (O/sub 2/, CO/sub 2/, and H/sub 2/O) on the identities and abundances of trace element vapor species. Coincident with experimental studies, trace element vaporization behavior was evaluated by Gibbs energy minimization calculations. A data base including both solution and pure condensed and gaseous components was compiled. The behavior of Wyodak coal at 1 atm total pressure was evaluated over the temperature range 300--1800 K and the oxygen partial pressure range from 10/sup /minus/1/ to 10/sup /minus/25/ atm. Results were used to evaluate the effects on trace element volatility of several proposed strategies for containment removal. 13 refs., 23 figs., 23 tabs.

  3. Mars water vapor, near-surface (United States)

    Ryan, J. A.; Sharman, R. D.; Lucich, R. D.


    In a previous paper we concluded that the temperature sensors aboard the Viking landers (VL-1 and VL-2) were detecting the water vapor frost point. Analysis of one Mars year of data at both lander sites substantiates this conclusion. At VL-1 it is found that the water vapor mixing ratio is constant with height through the bulk of the atmosphere, most of the time. Exceptions are during the onset phases of the two major dust storms when temporary enhancement of near-surface vapor occurs (the same phenomenon is observed at VL-2), and some depletion of near-surface vapor during the decay phase of the first storm, possibly the second storm as well. The former suggests near-surface, northward transport of water vapor with the storms. The latter suggests adsorption of vapor on dust particles followed by surface deposition. At VL-2, severe near-surface depletion of water vapor occurs during northern autumn and winter. The residual vapor is in equilibrium with the surface condensate observed at the site during this period, indicating that the source region for the condensate must be aloft with downward transport by dust fall-out. Since the near-surface water vapor mixing ratio and concentration at VL-1 generally parallels the column abundance over VL-1 obtained by the orbiters, this suggests that VL-1 can be used to give a measure of column abundance for as long as the temperature sensors remain operational.

  4. Energy characteristics of a transverse-discharge copper vapor laser

    Energy Technology Data Exchange (ETDEWEB)

    Artem' ev, A.Y.; Babeiko, Y.A.; Bakhtin, O.M.; Borovich, B.L.; Vasil' ev, L.A.; Gerts, V.E.; Nalegach, E.P.; Ratnikov, G.E.; Tatarintsev, L.V.; Ul' yanov, A.N.


    A study was made of the basic energy characteristics of a transverse-discharge copper vapor laser. The average laser output power in the yellow and green lasing components was determined as a function of the amplitude and repetition frequency of the excitation pulses, temperature of the discharge tube walls, and buffer gas pressure. The current-voltage characteristics of the discharge were investigated. An average laser output power of 75 W was obtained, at a pulse repetition frequency of 3 kHz.

  5. Enthalpy model for heating, melting, and vaporization in laser ablation

    Directory of Open Access Journals (Sweden)

    Vasilios Alexiades


    Full Text Available Laser ablation is used in a growing number of applications in various areas including medicine, archaeology, chemistry, environmental and materials sciences. In this work the heat transfer and phase change phenomena during nanosecond laser ablation of a copper (Cu target in a helium (He background gas at atmospheric pressure are presented. An enthalpy model is outlined, which accounts for heating, melting, and vaporization of the target. As far as we know, this is the first model that connects the thermodynamics and underlying kinetics of this challenging phase change problem in a self-consistent way.

  6. Motion of liquid plugs between vapor bubbles in capillary tubes: a comparison between fluids (United States)

    Bertossi, Rémi; Ayel, Vincent; Mehta, Balkrishna; Romestant, Cyril; Bertin, Yves; Khandekar, Sameer


    Pulsating heat pipes (PHP) are now well-known devices in which liquid/vapor slug flow oscillates in a capillary tube wound between hot and cold sources. In this context, this paper focuses on the motion of the liquid plug, trapped between vapor bubbles, moving in capillary tubes, to try to better understand the thermo-physical phenomena involved in such devices. This study is divided into three parts. In the first part, an experimental study presents the evolution of the vapor pressure during the evaporation process of a liquid thin film deposited from a liquid plug flowing in a heated capillary tube: it is found that the behavior of the generated and removed vapor can be very different, according to the thermophysical properties of the fluids. In the second part, a transient model allows to compare, in terms of pressure and duration, the motion of a constant-length liquid plug trapped between two bubbles subjected to a constant difference of vapor pressure: the results highlight that the performances of the four fluids are also very different. Finally, a third model that can be considered as an improvement of the second one, is also presented: here, the liquid slug is surrounded by two vapor bubbles, one subjected to evaporation, the pressure in both bubbles is now a result of the calculation. This model still allows comparing the behaviors of the fluid. Even if our models are quite far from a complete model of a real PHP, results do indicate towards the applicability of different fluids as suitable working fluids for PHPs, particularly in terms of the flow instabilities which they generate.

  7. Preconditioning of the YSZ-NiO Fuel Cell Anode in Hydrogenous Atmospheres Containing Water Vapor. (United States)

    Vasyliv, Bogdan; Podhurska, Viktoriya; Ostash, Orest


    The YSZ-NiO ceramics for solid oxide fuel cells (SOFCs) anode have been investigated. A series of specimens were singly reduced in a hydrogenous atmosphere (Ar-5 vol% H2 mixture) at 600 °C under the pressure of 0.15 MPa or subjected to 'reduction in the mixture-oxidation in air' (redox) cycling at 600 °C. The YSZ-Ni cermets formed in both treatment conditions were then aged in 'water vapor in Ar-5 vol% H2 mixture' atmosphere at 600 °C under the pressure of 0.15 MPa. Additionally, the behaviour of the as-received material in this atmosphere was studied. It was revealed that small amount of water vapor in Ar-5 vol% H2 mixture (water vapor pressure below 0.03 MPa) does not affect the reduction of the nickel phase in the YSZ-NiO ceramics, but causes some changes in the YSZ-Ni cermet structure. In particular, nanopore growth in tiny Ni particles takes place. At higher concentration of water vapor in the mixture (water vapor pressure above 0.03-0.05 MPa), converse changes in the kinetics of reduction occur. The best physical and mechanical properties were revealed for the material treated by redox cycling after holding at 600 °C in water depleted gas mixture. The dual effect of water vapor on nickel-zirconia anode behaviour is discussed basing on scanning electron microscopy analysis data, material electrical conductivity, and strength.

  8. Vaporization response of evaporating drops with finite thermal conductivity (United States)

    Agosta, V. D.; Hammer, S. S.


    A numerical computing procedure was developed for calculating vaporization histories of evaporating drops in a combustor in which travelling transverse oscillations occurred. The liquid drop was assumed to have a finite thermal conductivity. The system of equations was solved by using a finite difference method programmed for solution on a high speed digital computer. Oscillations in the ratio of vaporization of an array of repetitivity injected drops in the combustor were obtained from summation of individual drop histories. A nonlinear in-phase frequency response factor for the entire vaporization process to oscillations in pressure was evaluated. A nonlinear out-of-phase response factor, in-phase and out-of-phase harmonic response factors, and a Princeton type 'n' and 'tau' were determined. The resulting data was correlated and is presented in graphical format. Qualitative agreement with the open literature is obtained in the behavior of the in-phase response factor. Quantitatively the results of the present finite conductivity spray analysis do not correlate with the results of a single drop model.

  9. Vapor transport through short hydrophobic nanopores for desalination (United States)

    Lee, Jongho; O'Hern, Sean; Laoui, Tahar; Rahman, Faizur; Karnik, Rohit


    We propose a concept for desalination of water by reverse osmosis (RO) using a vapor-trapping membrane composed of short hydrophobic nanopores and separates the salt water (feed) and the fresh water (permeate) on each side. The feed water is vaporized by applied pressure and the water vapor condenses on the permeate side accompanied by recovery of latent heat. A probabilistic model based on rarified gas conditions predicted 3-5 times larger mass flux by the proposed membrane than conventional RO membranes at temperatures in the range of 30-50C. To realize the short hydrophobic nanopores, gold was deposited at the entrance of alumina pores followed by SAM formation. The fraction of leaking pores was confirmed to be less than 0.2% using a calcium ion indicator (Fluo-4). Finally, a microfluidic flow cell was fabricated for characterizing the transport properties of the membranes. The authors would like to thank the King Fahd University of Petroleum and Minerals in Dhahran, Saudi Arabia, for funding the research reported in this paper through the Center for Clean Water and Clean Energy at MIT and KFUPM.

  10. Nonlinear optical properties of atomic vapor and semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Doseok [Univ. of California, Berkeley, CA (United States). Dept. of Physics


    This thesis contains the study of highly forbidden resonant second harmonic generation (SHG) in atomic potassium vapor using tunable picosecond pulses. Various output characteristics of vapor SHG have been investigated including the input intensity dependence, potassium vapor density dependence, buffer gas pressure dependence, and spatial profile. Recently, the discovery of new nonlinear optical crystals such as barium borate (β-BaB2O4, BBO) and lithium borate (LiB3O5, LBO) has greatly improved the performance of a tunable coherent optical devices based on optical parametric generation and amplification. In the second part of this thesis, a homebuilt picosecond optical parametric generator/amplifier (OPG/OPA) system is described in detail, including its construction details and output characteristics. This laser device has found many useful applications in spectroscopic studies including surface nonlinear optical spectroscopy via sum-frequency generation (SFG). The last part of this thesis reports studies on multiphoton-excited photoluminescence from porous silicon and GaN. Multiphoton excitation and photoluminescence can give numerous complementary information about semiconductors not obtainable with one-photon, above-bandgap excitation.

  11. Adsorption characteristics of water vapor on ferroaluminophosphate for desalination cycle

    KAUST Repository

    Kim, Youngdeuk


    The adsorption characteristics of microporous ferroaluminophosphate adsorbent (FAM-Z01, Mitsubishi Plastics) are evaluated for possible application in adsorption desalination and cooling (AD) cycles. A particular interest is its water vapor uptake behavior at assorted adsorption temperatures and pressures whilst comparing them to the commercial silica gels of AD plants. The surface characteristics are first carried out using N2 gas adsorption followed by the water vapor uptake analysis for temperature ranging from 20°C to 80°C. We propose a hybrid isotherm model, composing of the Henry and the Sips isotherms, which can be integrated to satisfactorily fit the experimental data of water adsorption on the FAM-Z01. The hybrid model is selected to fit the unusual isotherm shapes, that is, a low adsorption in the initial section and followed by a rapid vapor uptake leading to a likely micropore volume filling by hydrogen bonding and cooperative interaction in micropores. It is shown that the equilibrium adsorption capacity of FAM-Z01 can be up to 5 folds higher than that of conventional silica gels. Owing to the quantum increase in the adsorbate uptake, the FAM-Z01 has the potential to significantly reduce the footprint of an existing AD plant for the same output capacity. © 2014 Elsevier B.V.

  12. New Regenerative Cycle for Vapor Compression Refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Mark J. Bergander


    second step of compression. In the proposed system, the compressor compresses the vapor only to 50-60% of the final pressure, while the additional compression is provided by a jet device using internal potential energy of the working fluid flow. Therefore, the amount of mechanical energy required by a compressor is significantly reduced, resulting in the increase of efficiency (either COP or EER). The novelty of the cycle is in the equipment and in the way the multi-staging is accomplished. The anticipated result will be a new refrigeration system that requires less energy to accomplish a cooling task. The application of this technology will be for more efficient designs of: (1) Industrial chillers, (2) Refrigeration plants, (3) Heat pumps, (4) Gas Liquefaction plants, (5) Cryogenic systems.

  13. Enhanced Attenuation Technologies: Passive Soil Vapor Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K.; Looney, B.; Kamath, R.; Adamson, D.; Newell, C.


    Passive soil vapor extraction (PSVE) is an enhanced attenuation (EA) approach that removes volatile contaminants from soil. The extraction is driven by natural pressure gradients between the subsurface and atmosphere (Barometric Pumping), or by renewable sources of energy such as wind or solar power (Assisted PSVE). The technology is applicable for remediating sites with low levels of contamination and for transitioning sites from active source technologies such as active soil vapor extraction (ASVE) to natural attenuation. PSVE systems are simple to design and operate and are more cost effective than active systems in many scenarios. Thus, PSVE is often appropriate as an interim-remedial or polishing strategy. Over the past decade, PSVE has been demonstrated in the U.S. and in Europe. These demonstrations provide practical information to assist in selecting, designing and implementing the technology. These demonstrations indicate that the technology can be effective in achieving remedial objectives in a timely fashion. The keys to success include: (1) Application at sites where the residual source quantities, and associated fluxes to groundwater, are relatively low; (2) Selection of the appropriate passive energy source - barometric pumping in cases with a deep vadose zone and barrier (e.g., clay) layers that separate the subsurface from the atmosphere and renewable energy assisted PSVE in other settings and where higher flow rates are required. (3) Provision of sufficient access to the contaminated vadose zones through the spacing and number of extraction wells. This PSVE technology report provides a summary of the relevant technical background, real-world case study performance, key design and cost considerations, and a scenario-based cost evaluation. The key design and cost considerations are organized into a flowchart that dovetails with the Enhanced Attenuation: Chlorinated Organics Guidance of the Interstate Technology and Regulatory Council (ITRC). The PSVE

  14. Dissolution kinetics of volatile organic compound vapors in water : An integrated experimental and computational study

    NARCIS (Netherlands)

    G. Mahmoodlu, Mojtaba; Pontedeiro, Elizabeth M.; Pérez Guerrero, Jesús S.; Raoof, Amir; Hassanizadeh, S. Majid; van Genuchten, Martinus Th

    In this study we performed batch experiments to investigate the dissolution kinetics of trichloroethylene (TCE) and toluene vapors in water at room temperature and atmospheric pressure. The batch systems consisted of a water reservoir and a connected headspace, the latter containing a small glass

  15. Kinetic Study of the Chemical Vapor Deposition of Tantalum in Long Narrow Channels

    DEFF Research Database (Denmark)

    Mugabi, James Atwoki; Eriksen, Søren; Petrushina, Irina


    A kinetic study of the chemical vapor deposition of tantalum in long narrow channels is done to optimize the industrial process for the manufacture of tantalum coated plate heat exchangers. The developed model fits well at temperatures between 750 and 850 °C, and in the pressure range of25–990 mbar...

  16. Vapor-fed bio-hybrid fuel cell. (United States)

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


    Concentration and purification of ethanol and other biofuels from fermentations are energy-intensive processes, with amplified costs at smaller scales. To circumvent the need for these processes, and to potentially reduce transportation costs as well, we have previously investigated bio-hybrid fuel cells (FCs), in which a fermentation and FC are closely coupled. However, long-term operation requires strictly preventing the fermentation and FC from harming each other. We introduce here the concept of the vapor-fed bio-hybrid FC as a means of continuously extracting power from ongoing fermentations at ambient conditions. By bubbling a carrier gas (N2) through a yeast fermentation and then through a direct ethanol FC, we protect the FC anode from the catalyst poisons in the fermentation (which are non-volatile), and also protect the yeast from harmful FC products (notably acetic acid) and from build-up of ethanol. Since vapor-fed direct ethanol FCs at ambient conditions have never been systematically characterized (in contrast to vapor-fed direct methanol FCs), we first assess the effects on output power and conversion efficiency of ethanol concentration, vapor flow rate, and FC voltage. The results fit a continuous stirred-tank reactor model. Over a wide range of ethanol partial pressures (2-8 mmHg), power densities are comparable to those for liquid-fed direct ethanol FCs at the same temperature, with power densities >2 mW/cm(2) obtained. We then demonstrate the continuous operation of a vapor-fed bio-hybrid FC with fermentation for 5 months, with no indication of performance degradation due to poisoning (of either the FC or the fermentation). It is further shown that the system is stable, recovering quickly from disturbances or from interruptions in maintenance. The vapor-fed bio-hybrid FC enables extraction of power from dilute bio-ethanol streams without costly concentration and purification steps. The concept should be scalable to both large and small

  17. Working fluids selection for fishing boats waste heat powered organic Rankine-vapor compression ice maker (United States)

    Bu, Xianbiao; Wang, Lingbao; Li, Huashan


    To utilize waste heat from fishing boats, an organic Rankine cycle/vapor compression cycle system was employed for ice making and a thermodynamic model was developed. Six working fluids were selected and compared in order to identify suitable working fluids which may yield high system efficiencies. The calculated results show that R600a is most suitable working fluid through comprehensive comparison of efficiency, size parameter, pressure ratio, coefficient of performance, system pressure and safety.

  18. LNG fire and vapor control system technologies

    Energy Technology Data Exchange (ETDEWEB)

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


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

  19. Mechanics of gas-vapor bubbles

    NARCIS (Netherlands)

    Hao, Yue; Zhang, Yuhang; Prosperetti, Andrea


    Most bubbles contain a mixture of vapor and incondensible gases. While the limit cases of pure vapor and pure gas bubbles are well studied, much less is known about the more realistic case of a mixture. The bubble contents continuously change due to the combined effects of evaporation and

  20. Soil vapor extraction with dewatering

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, N.R. [Univ. of Waterloo, Ontario (Canada)


    The physical treatment technology of soil vapor extraction (SVE) is reliable, safe, robust, and able to remove significant amounts of mass at a relatively low cost. SVE combined with a pump-and-treat system to create a dewatered zone has the opportunity to remove more mass with the added cost of treating the extracted groundwater. Various limiting processes result in a significant reduction in the overall mass removal rates from a SVE system in porous media. Only pilot scale, limited duration SVE tests conducted in low permeability media have been reported in the literature. It is expected that the presence of a fracture network in low permeability media will add another complexity to the limiting conditions surrounding the SVE technology. 20 refs., 4 figs.

  1. Use of a novel new irrigation system to observe and model water vapor flow through dry soils (United States)

    Todman, L. C.; Ireson, A. M.; Butler, A. P.; Templeton, M.


    In dry soils hydraulic connectivity within the liquid water phase decreases and vapor flow becomes a significant transport mechanism for water. The temperature or solute concentration of the liquid phase affects the vapor pressure of the surrounding air, thus temperature or solute gradients can drive vapor flows. However, in extremely dry soils where water is retained by adsorption rather than capillarity, vapor flows can also occur. In such soils tiny changes in water content significantly affect the equilibrium vapor pressure in the soil, and hence small differences in water content can initiate vapor pressure gradients. In many field conditions this effect may be negligible compared to vapor flows driven by other factors. However, flows of this type are particularly significant in a new type of subsurface irrigation system which uses pervaporation, via a polymer tubing, as the mechanism for water supply. In this system, water enters the soil in vapor phase. Experiments using this system therefore provide a rare opportunity to observe vapor flows initiating from a subsurface source without significant injection of heat. A model was developed to simulate water flow through the soil in liquid and vapor phase. In this model it was assumed that the two phases were in equilibrium. The equilibrium relationship was defined by a new mathematical expression that was developed to fit experimental data collected to characterize the sorption isotherm of three soils (sand, saline sand and top soil). The osmotic potential of the saline sand was defined as a function of water content using a continuous mathematical expression. The model was then calibrated to fit the data from laboratory experiments, in which the vapor flow into and out of the soil were quantified. The model successfully reproduced experimental observations of the total water flux, relative humidity and water content distribution in three soil types. This suggests that the model, including the proposed

  2. Inhomogeneous Monte Carlo simulation of the vapor-liquid equilibrium of benzene between 300 K and 530 K

    Directory of Open Access Journals (Sweden)



    Full Text Available The inhomogeneous Monte Carlo technique is used in studying the vapor-liquid interface of benzene in a broad range of temperatures using the TraPPE potential field. The obtained values of the VLE parameters are in good agreement with the experimental values as well as with the results from GEMC simulations. In contrast to the GEMC, within one simulation box the inhomogeneous MC technique also yields information on the structural properties of the interphase between the two phases. The values of the vaporization enthalpy and the vapor pressure very well satisfy the Clausius-Clapeyron equation.

  3. MEMS Lubrication by In-Situ Tribochemical Reactions From the Vapor Phase.

    Energy Technology Data Exchange (ETDEWEB)

    Dugger, Michael Thomas; Asay, David B.; Kim, Seong H.


    Vapor Phase Lubrication (VPL) of silicon surfaces with pentanol has been demonstrated. Two potential show stoppers with respect to application of this approach to real MEMS devices have been investigated. Water vapor was found to reduce the effectiveness of VPL with alcohol for a given alcohol concentration, but the basic reaction mechanism observed in water-free environments is still active, and devices operated much longer in mixed alcohol and water vapor environments than with chemisorbed monolayer lubricants alone. Complex MEMS gear trains were successfully lubricated with alcohol vapors, resulting in a factor of 104 improvement in operating life without failure. Complex devices could be made to fail if operated at much higher frequencies than previously used, and there is some evidence that the observed failure is due to accumulation of reaction products at deeply buried interfaces. However, if hypothetical reaction mechanisms involving heated surfaces are valid, then the failures observed at high frequency may not be relevant to operation at normal frequencies. Therefore, this work demonstrates that VPL is a viable approach for complex MEMS devices in conventional packages. Further study of the VPL reaction mechanisms are recommended so that the vapor composition may be optimized for low friction and for different substrate materials with potential application to conventionally fabricated, metal alloy parts in weapons systems. Reaction kinetics should be studied to define effective lubrication regimes as a function of the partial pressure of the vapor phase constituent, interfacial shear rate, substrate composition, and temperature.

  4. Controls on water vapor isotopes over Roorkee, India: Impact of convective activities and depression systems (United States)

    Saranya, P.; Krishan, Gopal; Rao, M. S.; Kumar, Sudhir; Kumar, Bhishm


    The study evaluates the water vapor isotopic compositions and its controls with special reference to Indian Summer Monsoon (ISM) season at Roorkee, India. Precipitation is usually a discrete event spatially and temporally in this part of the country, therefore, the information provided is limited, while, the vapors have all time availability and have a significant contribution in the hydrological cycle locally or over a regional scale. Hence for understanding the processes altering the various sources, its isotopic signatures were studied. The Isotope Water Vapour Line (Iso Val) was drawn together with the Global Meteoric Water Line (GMWL) and the best fit line was δD = 5.42 * δ18O + 27.86. The precipitation samples were also collected during the study period and were best fitted with δD = 8.20(±0.18) * δ18O + 9.04(±1.16) in the Local Meteoric Water Line (LMWL). From the back trajectory analysis of respective vapor samples, it is unambiguous that three major sources viz; local vapor, western disturbance and monsoon vapor are controlling the fate of moisture over Roorkee. The d-excess in ground-level vapor (GLV) reveals the supply of recycled moisture from continental water bodies and evapo-transpiration as additional moisture sources to the study area. The intensive depletion in isotopic ratios was associated with the large-scale convective activity and low-pressure/cyclonic/depression systems formed over Bay of Bengal.

  5. Interfacial nonequilibrium and Bénard-Marangoni instability of a liquid-vapor system (United States)

    Margerit, J.; Colinet, P.; Lebon, G.; Iorio, C. S.; Legros, J. C.


    We study Bénard-Marangoni instability in a system formed by a horizontal liquid layer and its overlying vapor. The liquid is lying on a hot rigid plate and the vapor is bounded by a cold parallel plate. A pump maintains a reduced pressure in the vapor layer and evacuates the vapor. This investigation is undertaken within the classical quasisteady approximation for both the vapor and the liquid phases. The two layers are separated by a deformable interface. Temporarily frozen temperature and velocity distributions are employed at each instant for the stability analysis, limited to infinitesimal disturbances (linear regime). We use irreversible thermodynamics to model the phase change under interfacial nonequilibrium. Within this description, the interface appears as a barrier for transport of both heat and mass. Hence, in contrast with previous studies, we consider the possibility of a temperature jump across the interface, as recently measured experimentally. The stability analysis shows that the interfacial resistances to heat and mass transfer have a destabilizing influence compared to an interface that is in thermodynamic equilibrium. The role of the fluctuations in the vapor phase on the onset of instability is discussed. The conditions to reduce the system to a one phase model are also established. Finally, the influence of the evaporation parameters and of the presence of an inert gas on the marginal stability curves is discussed.

  6. Secondary Organic Aerosol Formation by Reactive Condensation of Glyoxal and Water Vapor (United States)

    Hastings, W. P.; Koehler, C. A.; de Haan, D. O.


    The formation of secondary organic aerosol particles by particle-phase reactions is currently of great interest. Glyoxal has been identified as a significant component in the particle phase in recent smog chamber aromatic oxidation studies. This is surprising because glyoxal has a high vapor pressure and phase partitioning theory would predict that it remain almost entirely in the gas phase. Growth of inorganic seed aerosol in a particle chamber was monitored by scanning mobility particle sizing during addition of gas-phase glyoxal and small amounts of water vapor. Glyoxal was observed to condense on inorganic seed aerosol at concentrations that are at least 100 times below its vapor pressure. This behavior can be explained by a chemical reaction: glyoxal is known to polymerize when exposed to water vapor. This polymerization may be a general mechanism for secondary aerosol formation by alpha-dicarbonyl compounds. The reactivity of hydrated and polymerized forms of glyoxal during analysis by gas chromatography was assessed. Hydrated glyoxal was found to convert to glyoxal at even slightly elevated temperatures in GC injection ports. We then showed that breakdown of solid-phase glyoxal trimer dihydrate, forming gas phase glyoxal and water vapor, occurs at temperatures just above 50 *C, the boiling point of glyoxal. These observations suggest that reports of particle-phase glyoxal are likely caused by GC sampling artifacts, and that the actual particulate species are instead polymerized forms of glyoxal. It does not appear that chemical derivatization protects glyoxal polymers from thermal breakdown during GC analysis. The existence in the particle phase of glyoxal polymers with negligable vapor pressures, rather than volatile glyoxal, is consistent with phase partitioning theory.

  7. Oxidative vaporization kinetics of Cr2O3 in oxygen from 1000 to 1300 C (United States)

    Stearns, C. A.; Kohl, F. J.; Fryburg, G. C.


    Rates of oxidative vaporization of Cr2O3 on preoxidized resistively heated chromium were determined in flowing oxygen at a pressure of 0.115 Torr for temperatures from 1000 to 1300 C. Reaction controlled rates were obtained from experimental rates by a gold calibration technique, and these rates were shown to agree with those predicted by thermochemical analysis. The activation energy obtained for the oxidative vaporization reaction corresponded numerically with the thermochemical enthalpy of the reaction. A theoretical equation is given for calculating the rate from thermodynamic data using boundary-layer theory.

  8. Shock vaporization and the accretion of the icy satellites of Jupiter and Saturn (United States)

    Ahrens, T. J.; Okeefe, J. D.


    The known properties of water and ice over a wide range of pressures and temperatures are applied to describe constraints on the shock vaporization processes for water and ice in the solar system. In particular, the role of impact vaporization acting during the formation of the Jovian and Saturnian satellites is examined in an attempt to explain the observed density in terms of composition of these rock and ice objects. A possible model of accretion of icy satellites is considered which predicts that the amount of ice devolatilization is related to planetary size.

  9. Heat transfer from vapor condensation in the region behind a shock wave (United States)

    Kobayashi, Yasunori; Oshiro, Naoto


    A series of experiments were conducted on shock wave propagation in a single-component two-phase(vapor-liquid) medium. A heat transfer mechanism in the flow field associated with vapor condensation behind a shock front was investigated. Measurements of pressure and temperature were made by conventional sensors and the flow field was visualized by schlieren photographs with the aid of high speed drum camera. Refrigerant-11 and benzene were used as a working fluid under a large void fraction of almost 100 percent. A flow field realized behind a shock front revealed significant features of ineffective compressibility and complicated flow patterns, which are largely different from those of pure gases.

  10. Analysis on Characteristics of Radiosonde Bias Using GPS Precipitable Water Vapor

    Directory of Open Access Journals (Sweden)

    Chang-Geun Park


    Full Text Available As an observation instrument of the longest record of tropospheric water vapor, radiosonde data provide upper-air pressure (geopotential height, temperature, humidity and wind. However, the data have some well-known elements related to inaccuracy. In this article, radiosonde precipitable water vapor (PWV at Sokcho observatory was compared with global positioning system (GPS PWV during each summertime of year 2007 and 2008 and the biases were calculated. As a result, the mean bias showed negative values regardless of the rainfall occurrence. In addition, on the basis of GPS PWV, the maximum root mean square error (RMSE was 5.67 mm over the radiosonde PWV.

  11. Isothermal Vapor-Liquid Equilibrium of Methanol + Glycerol and 1-Propanol + Glycerol

    Directory of Open Access Journals (Sweden)

    Annas Wiguno


    Full Text Available Isothermal vapor-liquid equilibrium (VLE data for two binary mixtures of methanol + glycerol and 1-propanol + glycerol were determined at the temperature range from (313.15 to 363.15 K using a simple quasi-static ebulliometer. All systems showed that the vapor pressures increased with increasing alcohols (methanol or 1-propanol concentrations at corresponding system. The Wilson, Non-Random Two-Liquid (NRTL and Universal Quasi-Chemical (UNIQUAC activity coefficient models were used to correlate the experimental data. Both systems showed slightly deviations from the ideal liquid phase behavior.

  12. Bulk Growth of Wide Band Gap II-VI Compound Semiconductors by Physical Vapor Transport (United States)

    Su, Ching-Hua


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

  13. Quantifying liquid boundary and vapor distributions in a fuel spray by rainbow schlieren deflectometry. (United States)

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


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

  14. Continuous growth of single-wall carbon nanotubes using chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Grigorian, Leonid; Hornyak, Louis; Dillon, Anne C; Heben, Michael J


    The invention relates to a chemical vapor deposition process for the continuous growth of a carbon single-wall nanotube where a carbon-containing gas composition is contacted with a porous membrane and decomposed in the presence of a catalyst to grow single-wall carbon nanotube material. A pressure differential exists across the porous membrane such that the pressure on one side of the membrane is less than that on the other side of the membrane. The single-wall carbon nanotube growth may occur predominately on the low-pressure side of the membrane or, in a different embodiment of the invention, may occur predominately in between the catalyst and the membrane. The invention also relates to an apparatus used with the carbon vapor deposition process.

  15. Continuous growth of single-wall carbon nanotubes using chemical vapor deposition (United States)

    Grigorian, Leonid [Raymond, OH; Hornyak, Louis [Evergreen, CO; Dillon, Anne C [Boulder, CO; Heben, Michael J [Denver, CO


    The invention relates to a chemical vapor deposition process for the continuous growth of a carbon single-wall nanotube where a carbon-containing gas composition is contacted with a porous membrane and decomposed in the presence of a catalyst to grow single-wall carbon nanotube material. A pressure differential exists across the porous membrane such that the pressure on one side of the membrane is less than that on the other side of the membrane. The single-wall carbon nanotube growth may occur predominately on the low-pressure side of the membrane or, in a different embodiment of the invention, may occur predominately in between the catalyst and the membrane. The invention also relates to an apparatus used with the carbon vapor deposition process.

  16. Water Vapor Permeation in Plastics

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Paul E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kouzes, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)


    Polyvinyl toluene (PVT) and polystyrene (PS) (referred to as “plastic scintillator”) are used for gamma ray detectors. A significant decrease in radiation detection performance has been observed in some PVT-based gamma-ray detectors in systems in outdoor environments as they age. Recent studies have revealed that plastic scintillator can undergo an environmentally related material degradation that adversely affects gamma ray detection performance under certain conditions and histories. A significant decrease in sensitivity has been seen in some gamma-ray detectors in some systems as they age. The degradation of sensitivity of plastic scintillator over time is due to a variety of factors, and the term “aging” is used to encompass all factors. Some plastic scintillator samples show no aging effects (no significant change in sensitivity over more than 10 years), while others show severe aging (significant change in sensitivity in less than 5 years). Aging effects arise from weather (variations in heat and humidity), chemical exposure, mechanical stress, light exposure, and loss of volatile components. The damage produced by these various causes can be cumulative, causing observable damage to increase over time. Damage may be reversible up to some point, but becomes permanent under some conditions. The objective of this report is to document the phenomenon of permeability of plastic scintillator to water vapor and to derive the relationship between time, temperature, humidity and degree of water penetration in plastic. Several conclusions are documented about the properties of water permeability of plastic scintillator.

  17. Vapor Cavitation in Dynamically Loaded Journal Bearings (United States)

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


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

  18. External fuel vaporization study, phase 1 (United States)

    Szetela, E. J.; Chiappetta, L.


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

  19. DMSP SSMT/2 - Atmospheric Water Vapor Profiler (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SSM/T-2 sensor is a five channel, total power microwave radiometer with three channels situated symmetrically about the 183.31 GHz water vapor resonance line and...

  20. Water Vapor Corrosion in EBC Constituent Materials (United States)

    Kowalski, Benjamin; Fox, Dennis; Jacobson, Nathan S.


    Environmental Barrier Coating (EBC) materials are sought after to protect ceramic matrix composites (CMC) in high temperature turbine engines. CMCs are particularly susceptible to degradation from oxidation, Ca-Al-Mg-Silicate (CMAS), and water vapor during high temperature operation which necessitates the use of EBCs. However, the work presented here focuses on water vapor induced recession in EBC constituent materials. For example, in the presence of water vapor, silica will react to form Si(OH)4 (g) which will eventually corrode the material away. To investigate the recession rate in EBC constituent materials under high temperature water vapor conditions, thermal gravimetric analysis (TGA) is employed. The degradation process can then be modeled through a simple boundary layer expression. Ultimately, comparisons are made between various single- and poly-crystalline materials (e.g. TiO2, SiO2) against those found in literature.