Raspberry Ketone Analogs: Vapour Pressure Measurements and Attractiveness to Queensland Fruit Fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae)

PubMed Central

Hanssen, Benjamin L.; Jamie, Joanne F.; Jamie, Ian M.; Siderhurst, Matthew S.; Taylor, Phillip W.

2016-01-01

The Queensland fruit fly, Bactrocera tryoni (Froggatt) (Q-fly), is a major horticultural pest in Eastern Australia. Effective monitoring, male annihilation technique (MAT) and mass trapping (MT) are all important for control and require strong lures to attract flies to traps or toxicants. Lure strength is thought to be related in part to volatility, but little vapour pressure data are available for most Q-fly lures. Raspberry ketone (4-(4-hydroxyphenyl)-2-butanone) and analogs that had esters (acetyl, difluoroacetyl, trifluoroacetyl, formyl, propionyl) and ethers (methyl ether, trimethylsilyl ether) in replacement of the phenolic group, and in one case also had modification of the 2-butanone side chain, were measured for their vapour pressures by differential scanning calorimetry (DSC), and their attractiveness to Q-fly was assessed in small cage environmentally controlled laboratory bioassays. Maximum response of one category of compounds, containing both 2-butanone side chain and ester group was found to be higher than that of the other group of compounds, of which either of 2-butanone or ester functionality was modified. However, linear relationship between vapour pressure and maximum response was not significant. The results of this study indicate that, while volatility may be a factor in lure effectiveness, molecular structure is the dominating factor for the series of molecules investigated. PMID:27196605

Micromachining of silicon carbide on silicon fabricated by low-pressure chemical vapour deposition

NASA Astrophysics Data System (ADS)

Behrens, Ingo; Peiner, Erwin; Bakin, Andrey S.; Schlachetzki, Andreas

2002-07-01

We describe the fabrication of silicon carbide layers for micromechanical applications using low-pressure metal-organic chemical vapour deposition at temperatures below 1000 °C. The layers can be structured by lift-off using silicon dioxide as a sacrificial layer. A large selectivity with respect to silicon can be exploited for bulk micromachining. Thin membranes are fabricated which exhibit high mechanical quality, as necessary for applications in harsh environments.

Different physiological and behavioural effects of e-cigarette vapour and cigarette smoke in mice.

PubMed

Ponzoni, L; Moretti, M; Sala, M; Fasoli, F; Mucchietto, V; Lucini, V; Cannazza, G; Gallesi, G; Castellana, C N; Clementi, F; Zoli, M; Gotti, C; Braida, D

2015-10-01

Nicotine is the primary addictive substance in tobacco smoke and electronic cigarette (e-cig) vapour. Methodological limitations have made it difficult to compare the role of the nicotine and non-nicotine constituents of tobacco smoke. The aim of this study was to compare the effects of traditional cigarette smoke and e-cig vapour containing the same amount of nicotine in male BALB/c mice exposed to the smoke of 21 cigarettes or e-cig vapour containing 16.8 mg of nicotine delivered by means of a mechanical ventilator for three 30-min sessions/day for seven weeks. One hour after the last session, half of the animals were sacrificed for neurochemical analysis, and the others underwent mecamylamine-precipitated or spontaneous withdrawal for the purposes of behavioural analysis. Chronic intermittent non-contingent, second-hand exposure to cigarette smoke or e-cig vapour led to similar brain cotinine and nicotine levels, similar urine cotinine levels and the similar up-regulation of α4β2 nicotinic acetylcholine receptors in different brain areas, but had different effects on body weight, food intake, and the signs of mecamylamine-precipitated and spontaneous withdrawal episodic memory and emotional responses. The findings of this study demonstrate for the first time that e-cig vapour induces addiction-related neurochemical, physiological and behavioural alterations. The fact that inhaled cigarette smoke and e-cig vapour have partially different dependence-related effects indicates that compounds other than nicotine contribute to tobacco dependence. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

Height-related trends in stomatal sensitivity to leaf-to-air vapour pressure deficit in a tall conifer

Treesearch

D.R. Woodruff; F.C. Meinzer; K.A. McCulloh

2010-01-01

Stomatal responses to leaf-to-air vapour pressure deficit (LVPD), leaf water potential components, and cuticular properties were characterized for Douglas-fir (Pseudotsuga menziesii) foliage collected from treetops along a height gradient from 5 m to 58 m in order to explore height-related trends in stomatal sensitivity to LVPD and to investigate...

Review of vortex tube expansion in vapour compression refrigeration system

NASA Astrophysics Data System (ADS)

Liu, Yefeng; Yu, Jun

2018-05-01

A vortex tube expansion device replacing the throttle valve is proposed to improve the efficiency of vapour compression refrigeration cycle by reducing the loss of irreversibility in expansion process. The vortex tube is well-suited for these applications because it is simple, compact, light, quiet. Thus, this paper presents an overview of the thermodynamic analysis of vapour compression refrigeration cycle with vortex tube expansion device using different refrigerants. The paper also reviews the experiments and the calculations presented in previous studies on temperature separation in the vortex tube. The temperature separation mechanism and the flow-field inside the vortex tubes is explored by measuring the pressure, velocity, and temperature fields.

Micrometeorological measurements and vapour pressure deficit relations under in-field rainwater harvesting

NASA Astrophysics Data System (ADS)

Tesfuhuney, Weldemichael A.; Walker, Sue; Van Rensburg, Leon D.; Steyn, A. Stephan

2016-08-01

In a cropped field, microclimate and thermal stability conditions depend on the canopy structures and the prevailing weather. The main aim of the study therefore was to characterize the vertical profiles of weather variables within and above a maize (Zea mays L.) canopy and to describe the water vapour pressure deficit (VPD) under different atmospheric and soil surface conditions for both wide and narrow runoff strips with the in-field rainwater harvesting (IRWH) system. Micrometeorological measurements of wind, temperature and relative humidity were performed at eight levels, within canopy (1.8 and 2.1 m), and just above the canopy (2.4, 2.7, 3.0, and 3.3 m) up to reference levels (3.9 and 4.5 m) when the maize reached a maximum height of 2.2 m. Under incomplete canopy cover of the IRWH system, two important factors complicated evapotranspiration estimation, namely the local advection and high temperatures of the bare soil between adjacent plant rows. Diurnal variations of water vapour related to turbulence at each locality and its position in the thermal internal boundary layers. Generally, advection was more pronounced in wide runoff strips than narrow strips. On wide runoff strips the wind was more effective in replacing the air between the rows and maintained a higher driving force for evaporation. The maximum VPD over the narrow strips was observed at reference level during a dry day, at about 2.2 kPa in the afternoon, while wet day VPD reached a maximum of 1.8 kPa. The VPD of the wide runoff strips correlated negatively with wind speed, but showed a fairly positive correlation with some scattered values on wet days after rain. Therefore, profile characteristics within and above plant canopies played a key role in determining the VPD and consequently, could help to explain transpiration rates of crops. Hence, VPD relations enhanced the understanding of the heat energy exchange processes under the heterogeneous nature of maize canopy of the IRWH tillage system.

Diode laser-induced infrared fluorescence of water vapour

NASA Astrophysics Data System (ADS)

Li, Hejie; Hanson, Ronald K.; Jeffries, Jay B.

2004-07-01

Infrared laser-induced fluorescence (LIF) of water vapour was investigated for its potential as a spatially resolved gasdynamic diagnostic. A cw diode laser operating near 1392 nm was scanned across a single absorption transition in the ngr1 + ngr3 band of H2O in a static cell, and the resulting fluorescence signal was collected near 2.7 µm (both ngr1 and ngr3 bands). Experiments were conducted at low pressure in pure water vapour and mixtures of water vapour and N2 using a 20 mW laser in a double-pass arrangement. A simple analytical model was developed to relate LIF intensity to gas properties as a function of laser power. The spectrally resolved, single-line excitation spectrum was fitted with a Voigt profile, allowing inference of the water vapour temperature from the Doppler-broadened component of the measured fluorescence lineshape. A two-line excitation scheme was also investigated as a means of measuring temperature with reduced measurement time. From these initial measurements, we estimate that a practical sensor for atmospheric pressure applications would require a minimum of 1-2 W of laser power for two-line, fixed-wavelength temperature measurements and a minimum of about 70 W of power for scanned-wavelength measurements.

A diode laser sensor for rapid, sensitive measurements of gas temperature and water vapour concentration at high temperatures and pressures

NASA Astrophysics Data System (ADS)

Rieker, G. B.; Li, H.; Liu, X.; Jeffries, J. B.; Hanson, R. K.; Allen, M. G.; Wehe, S. D.; Mulhall, P. A.; Kindle, H. S.

2007-05-01

A near-infrared diode laser sensor is presented that is capable of measuring time-varying gas temperature and water vapour concentration at temperatures up to 1050 K and pressures up to 25 atm with a bandwidth of 7.5 kHz. Measurements with noise-equivalent-absorbances of the order of 10-3 (10-5 Hz-1/2) are made possible in dynamic environments through the use of wavelength modulation spectroscopy (WMS) with second harmonic detection (2f) on two water vapour spectral features near 7203.9 and 7435.6 cm-1. Laser performance characteristics that become important at the large modulation depths needed at high pressures are accounted for in the WMS-2f signal analysis, and the utility of normalization by the 1f signal to correct for variations in laser intensity, transmission and detector gain is presented. Laboratory measurements with the sensor system in a static cell with known temperature and pressure agree to 3% RMS in temperature and 4% RMS in H2O mole fraction for 500 < T < 900 K and 1 < P < 25 atm. The sensor time response is demonstrated in a high-pressure shock tube where shock wave transients are successfully captured, the average measured post-shock temperature agrees within 1% of the expected value, and H2O mole fraction agrees within 8%.

The ESA DUE GlobVapour Project

NASA Astrophysics Data System (ADS)

Schröder, M.; ESA Due Globvapour Project Team

2010-12-01

The European Space Agency (ESA) Data User Element (DUE) project series aims at bridging the gap between research projects and the sustainable provision of Earth Observation (EO) climate data products at an information level that fully responds to the operational needs of user communities. The ultimate objective of GlobVapour is to provide long-term coherent water vapour data sets exploiting the synergistic capabilities of different EO missions aiming at improved accuracies and enhanced temporal and spatial sampling better than those provided by the single sources. The project seeks to utilize the increasing potential of the synergistic capabilities of past, existing and upcoming satellite missions (ERS-1 and -2, ENVISAT, METOP, MSG as well as relevant non-European missions and in-situ data) in order to meet the increasing needs for coherent long-term water vapour datasets required by the scientific community. GlobVapour develops, validates and applies novel water vapour climate data sets derived from various sensors. More specifically, the primary objectives of the GlobVapour project are: 1)The development of multi-annual global water vapour data sets inclusive of error estimates based on carefully calibrated and inter-calibrated radiances. 2)The validation of the water vapour products against ground based, airborne and other satellite based measurements. 3) The provision of an assessment of the quality of different IASI water vapour profile algorithms developed by the project partners and other groups. 4) The provision of a complete processing system that can further strengthen operational production of the developed products. 5) A demonstration of the use of the products in the field of climate modelling, including applying alternative ways of climate model validation using forward radiation operators. 6) The promotion of the strategy of data set construction and the data sets themselves to the global research and operational community. The ultimate goal of the

Vapour phase motion in cryogenic systems containing superheated and subcooled liquids

NASA Astrophysics Data System (ADS)

Kirichenko, Yu. A.; Chernyakov, P. S.; Seregin, V. E.

The development of vent pipelines, and venting storage tanks for cryogenic liquids requires the knowledge of the law of motion as well as regularities of vapour content variation in the liquid and heat dissipation by the vapour phase. This is a theoretical study of the effect of superheating (subcooling) of the liquid, relative acceleration and reduced pressure upon the size and velocity of noninteracting vapour bubbles, moving in the liquid, and upon their resistance and heat transfer coefficients.

Vapour pressure deficit during growth has little impact on genotypic differences of transpiration efficiency at leaf and whole-plant level: an example from Populus nigra L.

PubMed

Rasheed, Fahad; Dreyer, Erwin; Richard, Béatrice; Brignolas, Franck; Brendel, Oliver; Le Thiec, Didier

2015-04-01

Poplar genotypes differ in transpiration efficiency (TE) at leaf and whole-plant level under similar conditions. We tested whether atmospheric vapour pressure deficit (VPD) affected TE to the same extent across genotypes. Six Populus nigra genotypes were grown under two VPD. We recorded (1) (13)C content in soluble sugars; (2) (18)O enrichment in leaf water; (3) leaf-level gas exchange; and (4) whole-plant biomass accumulation and water use. Whole-plant and intrinsic leaf TE and (13)C content in soluble sugars differed significantly among genotypes. Stomatal conductance contributed more to these differences than net CO2 assimilation rate. VPD increased water use and reduced whole-plant TE. It increased intrinsic leaf-level TE due to a decline in stomatal conductance. It also promoted higher (18)O enrichment in leaf water. VPD had no genotype-specific effect. We detected a deviation in the relationship between (13)C in leaf sugars and (13)C predicted from gas exchange and the standard discrimination model. This may be partly due to genotypic differences in mesophyll conductance, and to its lack of sensitivity to VPD. Leaf-level (13)C discrimination was a powerful predictor of the genetic variability of whole-plant TE irrespective of VPD during growth. © 2014 John Wiley & Sons Ltd.

Studies of the kinetics and mechanism of the oxidation of uranium by dry and moist air A model for determining the oxidation rate over a wide range of temperatures and water vapour pressures

NASA Astrophysics Data System (ADS)

McGillivray, G. W.; Geeson, D. A.; Greenwood, R. C.

1994-01-01

The rate of oxidation of uranium metal by moist air has been measured at temperatures from 115 to 350°C and water vapour pressures from 0 to 47 kPa (350 Torr). From this and from previously reported data, a model has been developed which allows the rate of uranium oxidation to be calculated at any particular combination of temperature and water vapour pressure of interest, in the range 0-350°C and 0-101.3 kPa (760 Torr). The model is based on the assumption that the surface concentration of water determines the rate of reaction and that the adsorption of water onto the oxide follows a Langmuir type isotherm. Theoretical plots of rate as a function of water vapour pressure and Arrhenius plots derived from the model have been shown to be in good agreement with experimental data. The model assumes separate contributions to the overall observed rate from oxygen and water vapour. Surface studies have been carried out using SIMS (secondary ion mass spectrometry). Depth profiling of the oxide produced by isotopically labelled reagents ( 18O 2 and H 218O), has shown that oxygen from both reactants is incorporated into the oxide layer in the ratio predicted by the kinetic model. This supports a mechanism in which oxygen and water vapour produce separate diffusing species (possibly O 2- and OH -).

The Droplets Condensate Centering in the Vapour Channel of Short Low Temperature Heat Pipes at High Heat Loads

NASA Astrophysics Data System (ADS)

Seryakov, A. V.; Shakshin, S. L.; Alekseev, A. P.

2017-11-01

The results of experimental studies of the process of condensate microdroplets centering contained in the moving moist vapour in the vapour channel of short heat pipes (HPs) for large thermal loads are presented. A vapour channel formed by capillary-porous insert in the form of the inner Laval-liked nozzle along the entire length of the HP. In the upper cover forming a condensation surface in the HP, on the diametrical line are installed capacitive sensors, forming three capacitors located at different distances from the longitudinal axis of the vapour channel. With increasing heat load and the boil beginning in the evaporator a large amount of moist vapour in the vapour channel of HP occur the pressure pulsation with frequency of 400-500 Hz and amplitude up to 1·104Pa. These pulsations affect the moving of the inertial droplets subsystem of the vapour and due to the heterogeneity of the velocity profile around the particle flow in the vapour channel at the diameter of microdroplets occurs transverse force, called the Saffman force and shear microdroplets to the center of vapour channel. Using installed in the top cover capacitors we can record the radial displacement of the condensable microdroplets.

The effect of vapour pressure deficit on stomatal conductance, sap pH and leaf-specific hydraulic conductance in Eucalyptus globulus clones grown under two watering regimes.

PubMed

Hernandez, Maria Jose; Montes, Fernando; Ruiz, Federico; Lopez, Gustavo; Pita, Pilar

2016-05-01

Stomatal conductance has long been considered of key interest in the study of plant adaptation to water stress. The expected increase in extreme meteorological events under a climate change scenario may compromise survival in Eucalyptus globulus plantations established in south-western Spain. We investigated to what extent changes in stomatal conductance in response to high vapour pressure deficits and water shortage are mediated by hydraulic and chemical signals in greenhouse-grown E. globulus clones. Rooted cuttings were grown in pots and submitted to two watering regimes. Stomatal conductance, shoot water potential, sap pH and hydraulic conductance were measured consecutively in each plant over 4 weeks under vapour pressure deficits ranging 0·42 to 2·25 kPa. Evapotranspiration, growth in leaf area and shoot biomass were also determined. There was a significant effect of both clone and watering regime in stomatal conductance and leaf-specific hydraulic conductance, but not in sap pH. Sap pH decreased as water potential and stomatal conductance decreased under increasing vapour pressure deficit. There was no significant relationship between stomatal conductance and leaf-specific hydraulic conductance. Stomata closure precluded shoot water potential from falling below -1·8 MPa. The percentage loss of hydraulic conductance ranged from 40 to 85 %. The highest and lowest leaf-specific hydraulic conductances were measured in clones from the same half-sib families. Water shortage reduced growth and evapotranspiration, decreases in evapotranspiration ranging from 14 to 32 % in the five clones tested. Changes in sap pH seemed to be a response to changes in atmospheric conditions rather than soil water in the species. Stomata closed after a considerable amount of hydraulic conductance was lost, although intraspecific differences in leaf-specific hydraulic conductance suggest the possibility of selection for improved productivity under water-limiting conditions

The effect of vapour pressure deficit on stomatal conductance, sap pH and leaf-specific hydraulic conductance in Eucalyptus globulus clones grown under two watering regimes

PubMed Central

Hernandez, Maria Jose; Montes, Fernando; Ruiz, Federico; Lopez, Gustavo; Pita, Pilar

2016-01-01

Background and Aims Stomatal conductance has long been considered of key interest in the study of plant adaptation to water stress. The expected increase in extreme meteorological events under a climate change scenario may compromise survival in Eucalyptus globulus plantations established in south-western Spain. We investigated to what extent changes in stomatal conductance in response to high vapour pressure deficits and water shortage are mediated by hydraulic and chemical signals in greenhouse-grown E. globulus clones. Methods Rooted cuttings were grown in pots and submitted to two watering regimes. Stomatal conductance, shoot water potential, sap pH and hydraulic conductance were measured consecutively in each plant over 4 weeks under vapour pressure deficits ranging 0·42 to 2·25 kPa. Evapotranspiration, growth in leaf area and shoot biomass were also determined. Key Results There was a significant effect of both clone and watering regime in stomatal conductance and leaf-specific hydraulic conductance, but not in sap pH. Sap pH decreased as water potential and stomatal conductance decreased under increasing vapour pressure deficit. There was no significant relationship between stomatal conductance and leaf-specific hydraulic conductance. Stomata closure precluded shoot water potential from falling below −1·8 MPa. The percentage loss of hydraulic conductance ranged from 40 to 85 %. The highest and lowest leaf-specific hydraulic conductances were measured in clones from the same half-sib families. Water shortage reduced growth and evapotranspiration, decreases in evapotranspiration ranging from 14 to 32 % in the five clones tested. Conclusions Changes in sap pH seemed to be a response to changes in atmospheric conditions rather than soil water in the species. Stomata closed after a considerable amount of hydraulic conductance was lost, although intraspecific differences in leaf-specific hydraulic conductance suggest the possibility of selection for

Heat transfer and pressure drop of condensation of hydrocarbons in tubes

NASA Astrophysics Data System (ADS)

Fries, Simon; Skusa, Severin; Luke, Andrea

2018-03-01

The heat transfer coefficient and pressure drop are investigated for propane. Two different mild steel plain tubes and saturation pressures are considered for varying mass flux and vapour quality. The pressure drop is compared to the Friedel-Correlation with two different approaches to determine the friction factor. The first is calculation as proposed by Friedel and the second is through single phase pressure drop investigations. For lower vapour qualities the experimental results are in better agreement with the approach of the calculated friction factor. For higher vapour qualities the experimental friction factor is more precise. The pressure drop increases for a decreasing tube diameter and saturation pressure. The circumferential temperature profile and heat transfer coefficients are shown for a constant vapour quality at varying mass fluxes. The subcooling is highest for the bottom of the tube and lowest for the top. The average subcooling as well as the circumferential deviation decreases for rising mass fluxes. The averaged heat transfer coefficients are compared to the model proposed by Thome and Cavallini. The experimental results are in good agreement with both correlations, however the trend is better described with the correlation from Thome. The experimental heat transfer coefficients are under predicted by Thome and over predicted by Cavallini.

Vapour-liquid interfacial properties of square-well chains from density functional theory and Monte Carlo simulation.

PubMed

Martínez-Ruiz, Francisco José; Blas, Felipe J; Moreno-Ventas Bravo, A Ignacio; Míguez, José Manuel; MacDowell, Luis G

2017-05-17

The statistical associating fluid theory for attractive potentials of variable range (SAFT-VR) density functional theory (DFT) developed by [Gloor et al., J. Chem. Phys., 2004, 121, 12740-12759] is used to predict the interfacial behaviour of molecules modelled as fully-flexible square-well chains formed from tangentially-bonded monomers of diameter σ and potential range λ = 1.5σ. Four different model systems, comprising 4, 8, 12, and 16 monomers per molecule, are considered. In addition to that, we also compute a number of interfacial properties of molecular chains from direct simulation of the vapour-liquid interface. The simulations are performed in the canonical ensemble, and the vapour-liquid interfacial tension is evaluated using the wandering interface (WIM) method, a technique based on the thermodynamic definition of surface tension. Apart from surface tension, we also obtain density profiles, coexistence densities, vapour pressures, and critical temperature and density, paying particular attention to the effect of the chain length on these properties. According to our results, the main effect of increasing the chain length (at fixed temperature) is to sharpen the vapour-liquid interface and to increase the width of the biphasic coexistence region. As a result, the interfacial thickness decreases and the surface tension increases as the molecular chains get longer. The interfacial thickness and surface tension appear to exhibit an asymptotic limiting behaviour for long chains. A similar behaviour is also observed for the coexistence densities and critical properties. Agreement between theory and simulation results indicates that SAFT-VR DFT is only able to predict qualitatively the interfacial properties of the model. Our results are also compared with simulation data taken from the literature, including the vapour-liquid coexistence densities, vapour pressures, and surface tension.

How do leaf hydraulics limit stomatal conductance at high water vapour pressure deficits?

PubMed

Bunce, James A

2006-08-01

A reduction in leaf stomatal conductance (g) with increasing leaf-to-air difference in water vapour pressure (D) is nearly ubiquitous. Ecological comparisons of sensitivity have led to the hypothesis that the reduction in g with increasing D serves to maintain leaf water potentials above those that would cause loss of hydraulic conductance. A reduction in leaf water potential is commonly hypothesized to cause stomatal closure at high D. The importance of these particular hydraulic factors was tested by exposing Abutilon theophrasti, Glycine max, Gossypium hirsutum and Xanthium strumarium to D high enough to reduce g and then decreasing ambient carbon dioxide concentration ([CO2]), and observing the resulting changes in g, transpiration rate and leaf water potential, and their reversibility. Reducing the [CO2] at high D increased g and transpiration rate and lowered leaf water potential. The abnormally high transpiration rates did not result in reductions in hydraulic conductance. Results indicate that low water potential effects on g at high D could be overcome by low [CO2], and that even lower leaf water potentials did not cause a reduction in hydraulic conductance in these well-watered plants. Reduced g at high D in these species resulted primarily from increased stomatal sensitivity to [CO2] at high D, and this increased sensitivity may mediate stomatal responses to leaf hydraulics at high D.

The solubility of gold in H 2 O-H 2 S vapour at elevated temperature and pressure

NASA Astrophysics Data System (ADS)

Zezin, Denis Yu.; Migdisov, Artashes A.; Williams-Jones, Anthony E.

2011-09-01

This experimental study sheds light on the complexation of gold in reduced sulphur-bearing vapour, specifically, in H 2O-H 2S gas mixtures. The solubility of gold was determined in experiments at temperatures of 300, 350 and 365 °C and reached 2.2, 6.6 and 6.3 μg/kg, respectively. The density of the vapour varied from 0.02 to 0.22 g/cm 3, the mole fraction of H 2S varied from 0.03 to 0.96, and the pressure in the cell reached 263 bar. Statistically significant correlations of the amount of gold dissolved in the fluid with the fugacity of H 2O and H 2S permit the experimental data to be fitted to a solvation/hydration model. According to this model, the solubility of gold in H 2O-H 2S gas mixtures is controlled by the formation of sulphide or bisulphide species solvated by H 2S or H 2O molecules. Formation of gold sulphide species is favoured statistically over gold bisulphide species and thus the gold is interpreted to dissolve according to reactions of the form: Au(s)+(n+1)HS(g)=AuS·(HS)n(g)+H(g) Au(s)+HS(g)+mHO(g)=AuS·(HO)m(g)+H(g) Equilibrium constants for Reaction (A1) and the corresponding solvation numbers ( K A1 and n) were evaluated from the study of Zezin et al. (2007). The equilibrium constants as well as the hydration numbers for Reaction (A2) ( K A2 and m) were adjusted simultaneously by a custom-designed optimization algorithm and were tested statistically. The resulting values of log K A2 and m are -15.3 and 2.3 at 300 and 350 °C and -15.1 and 2.2 at 365 °C, respectively. Using the calculated stoichiometry and stability of Reactions (A1) and (A2), it is now possible to quantitatively evaluate the contribution of reduced sulphur species to the transport of gold in aqueous vapour at temperatures up to 365 °C. This information will find application in modelling gold ore-forming processes in vapour-bearing magmatic hydrothermal systems, notably those of epithermal environments.

Stomatal acclimation to vapour pressure deficit doubles transpiration of small tree seedlings with warming.

PubMed

Marchin, Renée M; Broadhead, Alice A; Bostic, Laura E; Dunn, Robert R; Hoffmann, William A

2016-10-01

Future climate change is expected to increase temperature (T) and atmospheric vapour pressure deficit (VPD) in many regions, but the effect of persistent warming on plant stomatal behaviour is highly uncertain. We investigated the effect of experimental warming of 1.9-5.1 °C and increased VPD of 0.5-1.3 kPa on transpiration and stomatal conductance (gs ) of tree seedlings in the temperate forest understory (Duke Forest, North Carolina, USA). We observed peaked responses of transpiration to VPD in all seedlings, and the optimum VPD for transpiration (Dopt ) shifted proportionally with increasing chamber VPD. Warming increased mean water use of Carya by 140% and Quercus by 150%, but had no significant effect on water use of Acer. Increased water use of ring-porous species was attributed to (1) higher air T and (2) stomatal acclimation to VPD resulting in higher gs and more sensitive stomata, and thereby less efficient water use. Stomatal acclimation maintained homeostasis of leaf T and carbon gain despite increased VPD, revealing that short-term stomatal responses to VPD may not be representative of long-term exposure. Acclimation responses differ from expectations of decreasing gs with increasing VPD and may necessitate revision of current models based on this assumption. © 2016 John Wiley & Sons Ltd.

Behaviour of the iron vapour core in the arc of a controlled short-arc GMAW process with different shielding gases

NASA Astrophysics Data System (ADS)

Wilhelm, G.; Kozakov, R.; Gött, G.; Schöpp, H.; Uhrlandt, D.

2012-02-01

The controlled metal transfer process (CMT) is a variation of the gas metal arc welding (GMAW) process which periodically varies wire feeding speed. Using a short-arc burning phase to melt the wire tip before the short circuit, heat input to the workpiece is reduced. Using a steel wire and a steel workpiece, iron vapour is produced in the arc, its maximum concentration lying centrally. The interaction of metal vapour and welding gas considerably impacts the arc profile and, consequently, the heat transfer to the weldpool. Optical emission spectroscopy has been applied to determine the radial profiles of the plasma temperature and iron vapour concentration, as well as their temporal behaviour in the arc period for different mixtures of Ar, O2 and CO2 as shielding gases. Both the absolute iron vapour density and the temporal expansion of the iron core differ considerably for the gases Ar + 8%O2, Ar + 18% CO2 and 100% CO2 respectively. Pronounced minimum in the radial temperature profile is found in the arc centre in gas mixtures with high Ar content under the presence of metal vapour. This minimum disappears in pure CO2 gas. Consequently, the temperature and electrical and thermal conductivity in the arc when CO2 is used as a shielding gas are considerably lower.

Numerical Simulation of Pulsation Flow in the Vapour Channel of Short Low Temperature Heat Pipes at High Heat Loads

NASA Astrophysics Data System (ADS)

Seryakov, A. V.; Konkin, A. V.

2017-11-01

The results of the numerical simulation of pulsations in the Laval-liked vapour channel of short low-temperature range heat pipes (HPs) are presented. The numerical results confirmed the experimentally obtained increase of the frequency of pulsations in the vapour channel of short HPs with increasing overheat of the porous evaporator relative to the boiling point of the working fluid. The occurrence of pressure pulsations inside the vapour channel in a short HPs is a complex phenomenon associated with the boiling beginning in the capillary-porous evaporator at high heat loads, and appearance the excess amount of vapour above it, leading to the increase in pressure P to a value at which the boiling point TB of the working fluid becomes higher than the evaporator temperature Tev. Vapour clot spreads through the vapour channel and condense, and then a rarefaction wave return from condenser in the evaporator, the boiling in which is resumed and the next cycle of the pulsations is repeated. Numerical simulation was performed using finite element method implemented in the commercial program ANSYS Multiphisics 14.5 in the two-dimensional setting of axis symmetric moist vapour flow with third kind boundary conditions.

The oxidative corrosion of carbide inclusions at the surface of uranium metal during exposure to water vapour.

PubMed

Scott, T B; Petherbridge, J R; Harker, N J; Ball, R J; Heard, P J; Glascott, J; Allen, G C

2011-11-15

The reaction between uranium and water vapour has been well investigated, however discrepancies exist between the described kinetic laws, pressure dependence of the reaction rate constant and activation energies. Here this problem is looked at by examining the influence of impurities in the form of carbide inclusions on the reaction. Samples of uranium containing 600 ppm carbon were analysed during and after exposure to water vapour at 19 mbar pressure, in an environmental scanning electron microscope (ESEM) system. After water exposure, samples were analysed using secondary ion mass spectrometry (SIMS), focused ion beam (FIB) imaging and sectioning and transmission electron microscopy (TEM) with X-ray diffraction (micro-XRD). The results of the current study indicate that carbide particles on the surface of uranium readily react with water vapour to form voluminous UO(3) · xH(2)O growths at rates significantly faster than that of the metal. The observation may also have implications for previous experimental studies of uranium-water interactions, where the presence of differing levels of undetected carbide may partly account for the discrepancies observed between datasets. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Review of optimum temperature, humidity, and vapour pressure deficit for microclimate evaluation and control in greenhouse cultivation of tomato: a review

NASA Astrophysics Data System (ADS)

Shamshiri, Redmond Ramin; Jones, James W.; Thorp, Kelly R.; Ahmad, Desa; Man, Hasfalina Che; Taheri, Sima

2018-04-01

Greenhouse technology is a flexible solution for sustainable year-round cultivation of Tomato (Lycopersicon esculentum Mill), particularly in regions with adverse climate conditions or limited land and resources. Accurate knowledge about plant requirements at different growth stages, and under various light conditions, can contribute to the design of adaptive control strategies for a more cost-effective and competitive production. In this context, different scientific publications have recommended different values of microclimate parameters at different tomato growth stages. This paper provides a detailed summary of optimal, marginal and failure air and root-zone temperatures, relative humidity and vapour pressure deficit for successful greenhouse cultivation of tomato. Graphical representations of the membership function model to define the optimality degrees of these three parameters are included with a view to determining how close the greenhouse microclimate is to the optimal condition. Several production constraints have also been discussed to highlight the short and long-term effects of adverse microclimate conditions on the quality and yield of tomato, which are associated with interactions between suboptimal parameters, greenhouse environment and growth responses.

Time-dependent calculations of molten pool formation and thermal plasma with metal vapour in gas tungsten arc welding

NASA Astrophysics Data System (ADS)

Tanaka, M.; Yamamoto, K.; Tashiro, S.; Nakata, K.; Yamamoto, E.; Yamazaki, K.; Suzuki, K.; Murphy, A. B.; Lowke, J. J.

2010-11-01

A gas tungsten arc (GTA) was modelled taking into account the contamination of the plasma by metal vapour from the molten anode. The whole region of GTA atmosphere including the tungsten cathode, the arc plasma and the anode was treated using a unified numerical model. A viscosity approximation was used to express the diffusion coefficient in terms of viscosity of the shielding gas and metal vapour. The transient two-dimensional distributions of temperature, velocity of plasma flow and iron vapour concentration were predicted, together with the molten pool as a function of time for a 150 A arc current at atmospheric pressure, both for helium and argon gases. It was shown that the thermal plasma in the GTA was influenced by iron vapour from the molten pool surface and that the concentration of iron vapour in the plasma was dependent on the temperature of the molten pool. GTA on high sulfur stainless steel was calculated to discuss the differences between a low sulfur and a high sulfur stainless steel anode. Helium was selected as the shielding gas because a helium GTA produces more metal vapour than an argon GTA. In the GTA on a high sulfur stainless steel anode, iron vapour and current path were constricted. Radiative emission density in the GTA on high sulfur stainless steel was also concentrated in the centre area of the arc plasma together with the iron vapour although the temperature distributions were almost the same as that in the case of a low sulfur stainless steel anode.

A review of vapour lock issues during motor gasoline or automotive gasoline usage in piston engine aircraft

NASA Astrophysics Data System (ADS)

Thanikasalam, K.; Rahmat, M.; Fahmi, A. G. Mohammad; Zulkifli, A. M.; Shawal, N. Noor; Ilanchelvi, K.; Ananth, M.; Elayarasan, R.

2018-05-01

Since there is a developing practice of utilizing automotive fuels as flight fuel, there are higher chances of dangerous scenarios, particularly in the operation of piston aircraft engines. The use of motor vehicle gas (MOGAS) or aviation gas (AVGAS) in the operation of aviation piston engine increases the risk of vapour locking. A statistical examination of European aviation industry indicates that around 20,000 aircraft are affected either specifically or conceivably by the different negative impacts of gasoline blended with ethanol. Particularly, for most contemporary carburettor engines, there are risks associated with ethanol-admixed fuels that have potential to upset engine operation. The danger of vapour locking, which is the generation of gas bubbles inside the fuel system causing an impairment of fuel movement in the engine, is well documented particularly by studies on aircraft using MOGAS. Contrasted with AVGAS, MOGAS is inclined to demonstrate this phenomenon. Vapour lock is perhaps the leading serious problem that ought to be addressed if MOGAS is to be used as a substitute for AVGAS. Vapour lock problem is critical because it causes malfunctions to aircraft engines. Thus, an understanding of vapour handling ability of small aircraft is essential to establish safe operating confines at existing fuel temperature and pressures.

Characterization of sorption properties of selected soils from Lublin region by using water vapour adsorption method

NASA Astrophysics Data System (ADS)

Skic, Kamil; Boguta, Patrycja; Sokołowska, Zofia

2016-04-01

*The studies were carried out within the framework of a research project. The project was financed from funds of National Science Center on the base of decision number DEC-2013/11/D/NZ9/02545 Among many methods proposed to study sorption properties of soils an analysis of adsorption/ desorption isotherm is probably the easiest and most convenient one. It characterizes both quantity and quality of mineral and organic components and also their physical and physicochemical properties. The main aim of this study is comparison of sorption properties of selected Polish soils by using water vapour adsorption method. Samples were taken from the depth of 0-20 cm, from the Lublin region, eastern Poland. Soils were selected on the basis of their different physicochemical properties and were classified as: Haplic Fluvisol, Haplic Chernozem, Mollic Gleysol, Rendzic Phaeozem, Stagnic Luvisol, Haplic Cambisol (WG WRB 2006). Data taken from experimental adsorption isotherms were used to determine parameters of monolayer capacity, specific surface area and the total amount of vapour adsorbed at relative pressure of 0.974. Obtained adsorption and desorption isotherms reviled that adsorbate molecules interacted with the soil particles in different extent. Similar monolayer capacity was observed for Haplic Fluvisol, Haplic Chernozem and Stagnic Luvisol, while for Mollic Gleysol was more than 4 times higher. Mollic Gleysol was also characterized by highest values of specific surface area as well as quantity of adsorbed vapour at relative pressure of 0.974. Higher sorption was caused by presence of soil colloids which contains functional groups of a polar nature (mainly hydroxyls, phenolic and carboxyls). These groups similarly to silicates, oxides, hydratable cations as well as electric charge form adsorption centres for water vapour molecules.

A review of water recovery by vapour permeation through membranes.

PubMed

Bolto, Brian; Hoang, Manh; Xie, Zongli

2012-02-01

In vapour permeation the feed is a vapour, not a liquid as in pervaporation. The process employs a polymeric membrane as a semi-permeable barrier between the feed side under high pressure and the permeate side under low pressure. Separation is achieved by the different degrees to which components are dissolved in and diffuse through the membrane, the system working according to a solution-diffusion mechanism. The materials used in the membrane depend upon the types of compounds being separated, so water transport is favoured by hydrophilic material, whether organic or inorganic. The process is used for the dehydration of natural gas and various organic solvents, notably alcohol as biofuel, as well as the removal of water from air and its recovery from waste steam. Waste steam can be found in almost every plant/factory where steam is used. It is frequently contaminated and cannot be reused. Discharging the spent steam to the atmosphere is a serious energy loss and environmental issue. Recycling the steam can significantly improve the overall energy efficiency of an industry, which is responsible for massive CO(2) emissions. Steam separation at high fluxes and temperatures has been accomplished with a composite poly(vinyl alcohol) membrane containing silica nanoparticles, and also, less efficiently, with an inorganic zeolite membrane. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Vapour loss (``boiling'') as a mechanism for fluid evolution in metamorphic rocks

NASA Astrophysics Data System (ADS)

Trommsdorff, Volkmar; Skippen, George

1986-11-01

The calculation of fluid evolution paths during reaction progress is considered for multicomponent systems and the results applied to the ternary system, CO2-H2O-NaCl. Fluid evolution paths are considered for systems in which a CO2-rich phase of lesser density (vapour) is preferentially removed from the system leaving behind a saline aqueous phase (liquid). Such “boiling” leads to enrichment of the residual aqueous phase in dissolved components and, for certain reaction stoichiometries, to eventual saturation of the fluids in salt components. Distinctive textures, particularly radiating growths of prismatic minerals such as tremolite or diopside, are associated with saline fluid inclusions and solid syngenetic salt inclusions at a number of field localities. The most thoroughly studied of these localities is Campolungo, Switzerland, where metasomatic rocks have developed in association with fractures and veins at 500° C and 2,000 bars of pressure. The petrography of these rocks suggests that fluid phase separation into liquid and vapour has been an important process during metasomatism. Fracture systems with fluids at pressure less than lithostatic may facilitate the loss of the less dense vapour phase to conditions of the amphibolite facies.

A novel method of measuring the concentration of anaesthetic vapours using a dew-point hygrometer.

PubMed

Wilkes, A R; Mapleson, W W; Mecklenburgh, J S

1994-02-01

The Antoine equation relates the saturated vapour pressure of a volatile substance, such as an anaesthetic agent, to the temperature. The measurement of the 'dew-point' of a dry gas mixture containing a volatile anaesthetic agent by a dew-point hygrometer permits the determination of the partial pressure of the anaesthetic agent. The accuracy of this technique is limited only by the accuracy of the Antoine coefficients and of the temperature measurement. Comparing measurements by the dew-point method with measurements by refractometry showed systematic discrepancies up to 0.2% and random discrepancies with SDS up to 0.07% concentration in the 1% to 5% range for three volatile anaesthetics. The systematic discrepancies may be due to errors in available data for the vapour pressures and/or the refractive indices of the anaesthetics.

Transversely diode-pumped alkali metal vapour laser

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

Parkhomenko, A I; Shalagin, A M

2015-09-30

We have studied theoretically the operation of a transversely diode-pumped alkali metal vapour laser. For the case of high-intensity laser radiation, we have obtained an analytical solution to a complex system of differential equations describing the laser. This solution allows one to exhaustively determine all the energy characteristics of the laser and to find optimal parameters of the working medium and pump radiation (temperature, buffer gas pressure, and intensity and width of the pump spectrum). (lasers)

Intercomparison of TCCON and MUSICA Water Vapour Products

NASA Astrophysics Data System (ADS)

Weaver, D.; Strong, K.; Deutscher, N. M.; Schneider, M.; Blumenstock, T.; Robinson, J.; Notholt, J.; Sherlock, V.; Griffith, D. W. T.; Barthlott, S.; García, O. E.; Smale, D.; Palm, M.; Jones, N. B.; Hase, F.; Kivi, R.; Ramos, Y. G.; Yoshimura, K.; Sepúlveda, E.; Gómez-Peláez, Á. J.; Gisi, M.; Kohlhepp, R.; Warneke, T.; Dohe, S.; Wiegele, A.; Christner, E.; Lejeune, B.; Demoulin, P.

2014-12-01

We present an intercomparison between the water vapour products from the Total Carbon Column Observing Network (TCCON) and the MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA), two datasets from ground-based Fourier Transform InfraRed (FTIR) spectrometers with good global representation. Where possible, comparisons to radiosondes are also included. The near-infrared TCCON measurements are optimized to provide precise monitoring of greenhouse gases for carbon cycle studies; however, TCCON's retrievals also produce water vapour products. The mid-infrared MUSICA products result from retrievals optimized to give precise and accurate information about H2O, HDO, and δD. The MUSICA water vapour products have been validated by extensive intercomparisons with H2O and δD in-situ measurements made from ground, radiosonde, and aircraft (Schneider et al. 2012, 2014), as well as by intercomparisons with satellite-based H2O and δD remote sensing measurements (Wiegele et al., 2014). This dataset provides a valuable reference point for other measurements of water vapour. This study is motivated by the limited intercomparisons performed for TCCON water vapour products and limited characterisation of their uncertainties. We compare MUSICA and TCCON products to assess the potential for TCCON measurements to contribute to studies of the water cycle, water vapour's role in climate and use as a tracer for atmospheric dynamics, and to evaluate the performance of climate models. The TCCON and MUSICA products result from measurements taken using the same FTIR instruments, enabling a comparison with constant instrumentation. The retrieval techniques differ, however, in their method and a priori information. We assess the impact of these differences and characterize the comparability of the TCCON and MUSICA datasets.

Effects of copper vapour on thermophysical properties of CO2-N2 plasma

NASA Astrophysics Data System (ADS)

Zhong, Linlin; Wang, Xiaohua; Rong, Mingzhe; Cressault, Yann

2016-10-01

CO2-N2 mixtures are often used as arc quenching medium (to replace SF6) in circuit breakers and shielding gas in arc welding. In such applications, copper vapour resulting from electrode surfaces can modify characteristics of plasmas. This paper therefore presents an investigation of the effects of copper on thermophysical properties of CO2-N2 plasma. The equilibrium compositions, thermodynamic properties (including mass density, specific enthalpy, and specific heat), transport coefficients (including electrical conductivity, viscosity, and thermal conductivity), and four kinds of combined diffusion coefficients due to composition gradients, applied electric fields, temperature gradients, and pressure gradients respectively, were calculated and discussed for CO2-N2 (mixing ratio 7:3) plasma contaminated by different proportions of copper vapour. The significant influences of copper were observed on all the properties of CO2-N2-Cu mixtures. The better ionization ability and larger molar mass of copper and larger collision integrals related to copper, should be responsible for such influences.

Artificially decreased vapour pressure deficit in field conditions modifies foliar metabolite profiles in birch and aspen

PubMed Central

Lihavainen, Jenna; Keinänen, Markku; Keski-Saari, Sarita; Kontunen-Soppela, Sari; Sõber, Anu; Oksanen, Elina

2016-01-01

Relative air humidity (RH) is expected to increase in northern Europe due to climate change. Increasing RH reduces the difference of water vapour pressure deficit (VPD) between the leaf and the atmosphere, and affects the gas exchange of plants. Little is known about the effects of decreased VPD on plant metabolism, especially under field conditions. This study was conducted to determine the effects of artificially decreased VPD on silver birch (Betula pendula Roth.) and hybrid aspen (Populus tremula L.×P. tremuloides Michx.) foliar metabolite and nutrient profiles in a unique free air humidity manipulation (FAHM) field experiment during the fourth season of humidity manipulation, in 2011. Long-term exposure to decreased VPD modified nutrient homeostasis in tree leaves, as demonstrated by a lower N concentration and N:P ratio in aspen leaves, and higher Na concentration and lower K:Na ratio in the leaves of both species in decreased VPD than in ambient VPD. Decreased VPD caused a shift in foliar metabolite profiles of both species, affecting primary and secondary metabolites. Metabolic adjustment to decreased VPD included elevated levels of starch and heptulose sugars, sorbitol, hemiterpenoid and phenolic glycosides, and α-tocopherol. High levels of carbon reserves, phenolic compounds, and antioxidants under decreased VPD may modify plant resistance to environmental stresses emerging under changing climate. PMID:27255929

Predictable "individual differences" in uptake and excretion of gases and lipid soluble vapours simulation study.

PubMed Central

Fiserova-Bergerova, V; Vlach, J; Cassady, J C

1980-01-01

A five-compartment pharmacokinetic model with two excretory pathways, exhalation and metabolism, based on first order kinetics is used to outline the effect of body build, pulmonary ventilation, and lipid content in blood on uptake, distribution, and clearance of low solubility gases and lipid soluble vapours during and after exposure. The model shows the extent that individual differences have on altering uptake and distribution, with consequent changes in blood concentration, rate of excretion, and toxicity, even when variations in these parameters are within physiological ranges. The model is also used to describe the concentration variation of inhaled substances in tissues of subjects exposed to concentrations with permitted excursions. During the same course of exposure, the tissue concentrations of low solubility gases fluctuate much more than tissue concentrations of lipid soluble vapours. The fluctuation is reduced by metabolism of inhaled substance. These conclusions are recommended for consideration whenever evaluating the effect of excursions above the threshold limit values used in the control of industrial exposures (by excursion factors). PMID:7370192

The effect of perfluorocarbon vapour on the measurement of respiratory tidal volume during partial liquid ventilation.

PubMed

Davies, M W; Dunster, K R

2000-08-01

During partial liquid ventilation perfluorocarbon vapour is present in the exhaled gases. The volumes of these gases are measured by pneumotachometers. Error in measuring tidal volumes will give erroneous measurement of lung compliance during partial liquid ventilation. We aim to compare measured tidal volumes with and without perfluorocarbon vapour using tidal volumes suitable for use in neonates. Tidal volumes were produced with a 100 ml calibration syringe from 20 to 100 ml and with a calibrated Harvard rodent ventilator from 2.5 to 20 ml. Control tidal volumes were drawn from a humidifier chamber containing water vapour and the PFC tidal volumes were drawn from a humidifier chamber containing water and perfluorocarbon (FC-77) vapour. Tidal volumes were measured by a fixed orifice, target, differential pressure flowmeter (VenTrak) or a hot-wire anenometer (Bear Cub) placed between the calibration syringe or ventilator and the humidifier chamber. All tidal volumes measured with perfluorocarbon vapour were increased compared with control (ANOVA p < 0.001 and post t-test p < 0.0001). Measured tidal volume increased from 7 to 16% with the fixed orifice type flow-meter, and from 35 to 41% with the hot-wire type. In conclusion, perfluorocarbon vapour flowing through pneumotachometers gives falsely high tidal volume measurements. Calculation of lung compliance must take into account the effect of perfluorocarbon vapour on the measurement of tidal volume.

Vapour Intrusion into Buildings - A Literature Review

EPA Science Inventory

This chapter provides a review of recent research on vapour intrusion of volatile organic compounds (VOCs) into buildings. The chapter builds on a report from Tillman and Weaver (2005) which reviewed the literature on vapour intrusion through 2005. Firstly, the term ‘vapour intru...

Vapour growth of argyrodite-type ionic conductors Cu 6PS 5Hal

NASA Astrophysics Data System (ADS)

Fiechter, S.; Eckstein, J.; Nitsche, R.

1983-03-01

Cu 6PS 5Hal compounds (with Hal = Cl, Br or I) have been crystallized around 950 K by CVT with P, S and Hal (and combinations thereof). Chemical insight into the transport processes was gained from dissociation pressure measurements and spectroscopic vapour analysis. Lacking thermochemical data of the compounds were obtained from Cp measurements. Models, derived for the CVT mechanisms, yield transport rates and directions which agree qualitatively with experiments. The main vapour species (for Hal = C1) are PSCI 3, S 2, PCI 3, P 4S 3 and (CuCl) 3. With a surplus of CuHal, VLS growth via liquid CuHal/Cu 2S phases was observed.

Studies of copper and gold vapour lasers

NASA Astrophysics Data System (ADS)

Clark, Graeme Lawrence

The work described in this thesis covers various aspects of pulsed copper and gold vapour lasers. The work is divided into four main parts : a computer model of the kinetics of the copper vapour laser discharge; construction and characterization of a copper vapour laser and a gold vapour laser system (to be used for photodynamic cancer treatment); analysis of the thermal processes occurring in the various forms of thermal insulation used in these lasers; and studies of the use of metal walls to confine a discharge plasma. The results of this work were combined in the design of the first copper vapour laser to use metal rather than an electrically insulating ceramic material for confinement of the discharge plasma. Laser action in copper vapour has been achieved in a number of metal-walled designs, with continuous lengths of metal ranging from 30 mm, in a segmented design, to 400 mm, where the discharge plasma was confined by two molybdenum tubes of this length. A theoretical explanation of the behaviour of plasmas in metal-walled discharge vessels is described.

Analysis of the sorption properties of different soils using water vapour adsorption and potentiometric titration methods

NASA Astrophysics Data System (ADS)

Skic, Kamil; Boguta, Patrycja; Sokołowska, Zofia

2016-07-01

Parameters of specific surface area as well as surface charge were used to determine and compare sorption properties of soils with different physicochemical characteristics. The gravimetric method was used to obtain water vapour isotherms and then specific surface areas, whereas surface charge was estimated from potentiometric titration curves. The specific surface area varied from 12.55 to 132.69 m2 g-1 for Haplic Cambisol and Mollic Gleysol soil, respectively, and generally decreased with pH (R=0.835; α = 0.05) and when bulk density (R=-0.736; α = 0.05) as well as ash content (R=-0.751; α = 0.05) increased. In the case of surface charge, the values ranged from 63.00 to 844.67 μmol g-1 Haplic Fluvisol and Mollic Gleysol, respecively. Organic matter gave significant contributions to the specific surface area and cation exchange capacity due to the large surface area and numerous surface functional groups, containing adsorption sites for water vapour molecules and for ions. The values of cation exchange capacity and specific surface area correlated linearly at the level of R=0.985; α = 0.05.

The millennium water vapour drop in chemistry-climate model simulations

NASA Astrophysics Data System (ADS)

Brinkop, Sabine; Dameris, Martin; Jöckel, Patrick; Garny, Hella; Lossow, Stefan; Stiller, Gabriele

2016-07-01

This study investigates the abrupt and severe water vapour decline in the stratosphere beginning in the year 2000 (the "millennium water vapour drop") and other similarly strong stratospheric water vapour reductions by means of various simulations with the state-of-the-art Chemistry-Climate Model (CCM) EMAC (ECHAM/MESSy Atmospheric Chemistry Model). The model simulations differ with respect to the prescribed sea surface temperatures (SSTs) and whether nudging is applied or not. The CCM EMAC is able to most closely reproduce the signature and pattern of the water vapour drop in agreement with those derived from satellite observations if the model is nudged. Model results confirm that this extraordinary water vapour decline is particularly obvious in the tropical lower stratosphere and is related to a large decrease in cold point temperature. The drop signal propagates under dilution to the higher stratosphere and to the poles via the Brewer-Dobson circulation (BDC). We found that the driving forces for this significant decline in water vapour mixing ratios are tropical sea surface temperature (SST) changes due to a coincidence with a preceding strong El Niño-Southern Oscillation event (1997/1998) followed by a strong La Niña event (1999/2000) and supported by the change of the westerly to the easterly phase of the equatorial stratospheric quasi-biennial oscillation (QBO) in 2000. Correct (observed) SSTs are important for triggering the strong decline in water vapour. There are indications that, at least partly, SSTs contribute to the long period of low water vapour values from 2001 to 2006. For this period, the specific dynamical state of the atmosphere (overall atmospheric large-scale wind and temperature distribution) is important as well, as it causes the observed persistent low cold point temperatures. These are induced by a period of increased upwelling, which, however, has no corresponding pronounced signature in SSTs anomalies in the tropics. Our free

Vapours of US and EU Market Leader Electronic Cigarette Brands and Liquids Are Cytotoxic for Human Vascular Endothelial Cells.

PubMed

Putzhammer, Raphaela; Doppler, Christian; Jakschitz, Thomas; Heinz, Katharina; Förste, Juliane; Danzl, Katarina; Messner, Barbara; Bernhard, David

2016-01-01

The present study was conducted to provide toxicological data on e-cigarette vapours of different e-cigarette brands and liquids from systems viewed as leaders in the e-cigarette market and to compare e-cigarette vapour toxicity to the toxicity of conventional strong high-nicotine cigarette smoke. Using an adapted version of a previously constructed cigarette smoke constituent sampling device, we collected the hydrophilic fraction of e-cigarette vapour and exposed human umbilical vein endothelial cells (HUVECs) to the mixture of compounds present in the vapour of 4 different single-use e-cigarettes, 6 different liquid vapours produced by the same refillable e-cigarette, and one e-cigarette with an exchangeable liquid cartridge. After incubation of cells with various concentrations and for various periods of time we analysed cell death induction, proliferation rates, the occurrence of intra-cellular reactive oxygen species, cell morphology, and we also measured e-cigarette heating coil temperatures. Overall, conventional cigarette smoke extract showed the most severe impact on endothelial cells. However, some e-cigarette vapour extracts showed high cytotoxicity, inhibition of cell proliferation, and alterations in cell morphology, which were comparable to conventional high-nicotine cigarettes. The vapours generated from different liquids using the same e-cigarette show substantial differences, pointing to the liquids as an important source for toxicity. E-cigarette vapour-mediated induction of oxidative stress was significant in one out of the 11 analysed vapours. There is a high variability in the acute cytotoxicity of e-cigarette vapours depending on the liquid and on the e-cigarettes used. Some products showed toxic effects close to a conventional high-nicotine cigarette. Liquid nicotine, menthol content, and the formation of acute intracellular reactive oxygen species do not seem to be the central elements in e-cigarette vapour toxicity.

Vapours of US and EU Market Leader Electronic Cigarette Brands and Liquids Are Cytotoxic for Human Vascular Endothelial Cells

PubMed Central

Putzhammer, Raphaela; Doppler, Christian; Jakschitz, Thomas; Heinz, Katharina; Förste, Juliane; Danzl, Katarina; Messner, Barbara; Bernhard, David

2016-01-01

The present study was conducted to provide toxicological data on e-cigarette vapours of different e-cigarette brands and liquids from systems viewed as leaders in the e-cigarette market and to compare e-cigarette vapour toxicity to the toxicity of conventional strong high-nicotine cigarette smoke. Using an adapted version of a previously constructed cigarette smoke constituent sampling device, we collected the hydrophilic fraction of e-cigarette vapour and exposed human umbilical vein endothelial cells (HUVECs) to the mixture of compounds present in the vapour of 4 different single-use e-cigarettes, 6 different liquid vapours produced by the same refillable e-cigarette, and one e-cigarette with an exchangeable liquid cartridge. After incubation of cells with various concentrations and for various periods of time we analysed cell death induction, proliferation rates, the occurrence of intra-cellular reactive oxygen species, cell morphology, and we also measured e-cigarette heating coil temperatures. Overall, conventional cigarette smoke extract showed the most severe impact on endothelial cells. However, some e-cigarette vapour extracts showed high cytotoxicity, inhibition of cell proliferation, and alterations in cell morphology, which were comparable to conventional high-nicotine cigarettes. The vapours generated from different liquids using the same e-cigarette show substantial differences, pointing to the liquids as an important source for toxicity. E-cigarette vapour-mediated induction of oxidative stress was significant in one out of the 11 analysed vapours. There is a high variability in the acute cytotoxicity of e-cigarette vapours depending on the liquid and on the e-cigarettes used. Some products showed toxic effects close to a conventional high-nicotine cigarette. Liquid nicotine, menthol content, and the formation of acute intracellular reactive oxygen species do not seem to be the central elements in e-cigarette vapour toxicity. PMID:27351725

Vapour sensitivity of an ALD hierarchical photonic structure inspired by Morpho.

PubMed

Poncelet, Olivier; Tallier, Guillaume; Mouchet, Sébastien R; Crahay, André; Rasson, Jonathan; Kotipalli, Ratan; Deparis, Olivier; Francis, Laurent A

2016-05-09

The unique architecture of iridescent Morpho butterfly scales is known to exhibit different optical responses to various vapours. However, the mechanism behind this phenomenon is not fully quantitatively understood. This work reports on process developments in the micro-fabrication of a Morpho-inspired photonic structure in atomic layer deposited (ALD) materials in order to investigate the vapour optical sensitivity of such artificial nanostructures. By developing recipes for dry and wet etching of ALD oxides, we micro-fabricated two structures: one combining Al2O3 and TiO2, and the other combining Al2O3 and HfO2. For the first time, we report the optical response of such ALD Morpho-like structures measured under a controlled flow of either ethanol or isopropyl alcohol (IPA) vapour. In spite of the small magnitude of the effect, the results show a selective vapour response (depending on the materials used).

Stratospheric water vapour in the vicinity of the Arctic polar vortex

NASA Astrophysics Data System (ADS)

Maturilli, M.; Fierli, F.; Yushkov, V.; Lukyanov, A.; Khaykin, S.; Hauchecorne, A.

2006-07-01

The stratospheric water vapour mixing ratio inside, outside, and at the edge of the polar vortex has been accurately measured by the FLASH-B Lyman-Alpha hygrometer during the LAUTLOS campaign in Sodankylä, Finland, in January and February 2004. The retrieved H2O profiles reveal a detailed view on the Arctic lower stratospheric water vapour distribution, and provide a valuable dataset for the validation of model and satellite data. Analysing the measurements with the semi-lagrangian advection model MIMOSA, water vapour profiles typical for the polar vortex' interior and exterior have been identified, and laminae in the observed profiles have been correlated to filamentary structures in the potential vorticity field. Applying the validated MIMOSA transport scheme to specific humidity fields from operational ECMWF analyses, large discrepancies from the observed profiles arise. Although MIMOSA is able to reproduce weak water vapour filaments and improves the shape of the profiles compared to operational ECMWF analyses, both models reveal a dry bias of about 1 ppmv in the lower stratosphere above 400 K, accounting for a relative difference from the measurements in the order of 20%. The large dry bias in the analysis representation of stratospheric water vapour in the Arctic implies the need for future regular measurements of water vapour in the polar stratosphere to allow the validation and improvement of climate models.

Comparison of interaction mechanisms of copper phthalocyanine and nickel phthalocyanine thin films with chemical vapours

NASA Astrophysics Data System (ADS)

Ridhi, R.; Singh, Sukhdeep; Saini, G. S. S.; Tripathi, S. K.

2018-04-01

The present study deals with comparing interaction mechanisms of copper phthalocyanine and nickel phthalocyanine with versatile chemical vapours: reducing, stable aromatic and oxidizing vapours namely; diethylamine, benzene and bromine. The variation in electrical current of phthalocyanines with exposure of chemical vapours is used as the detection parameter for studying interaction behaviour. Nickel phthalocyanine is found to exhibit anomalous behaviour after exposure of reducing vapour diethylamine due to alteration in its spectroscopic transitions and magnetic states. The observed sensitivities of copper phthalocyanine and nickel phthalcyanine films are different in spite of their similar bond numbers, indicating significant role of central metal atom in interaction mechanism. The variations in electronic transition levels after vapours exposure, studied using UV-Visible spectroscopy confirmed our electrical sensing results. Bromine exposure leads to significant changes in vibrational bands of metal phthalocyanines as compared to other vapours.

Mechanism of two-step vapour-crystal nucleation in a pore

NASA Astrophysics Data System (ADS)

van Meel, J. A.; Liu, Y.; Frenkel, D.

2015-09-01

We present a numerical study of the effect of hemispherical pores on the nucleation of Lennard-Jones crystals from the vapour phase. As predicted by Page and Sear, there is a narrow range of pore radii, where vapour-liquid nucleation can become a two-step process. A similar observation was made for different pore geometries by Giacomello et al. We find that the maximum nucleation rate depends on both the size and the adsorption strength of the pore. Moreover, a poe can be more effective than a planar wall with the same strength of attraction. Pore-induced vapour-liquid nucleation turns out to be the rate-limiting step for crystal nucleation. This implies that crystal nucleation can be enhanced by a judicious choice of the wetting properties of a microporous nucleating agent.

Evaluation of Direct Vapour Equilibration for Stable Isotope Analysis of Plant Water.

NASA Astrophysics Data System (ADS)

Millar, C. B.; McDonnell, J.; Pratt, D.

2017-12-01

The stable isotopes of water (2H and 18O), extracted from plants, have been utilized in a variety of ecohydrological, biogeochemical and climatological studies. The array of methods used to extract water from plants are as varied as the studies themselves. Here we perform a comprehensive inter-method comparison of six plant water extraction techniques: direct vapour equilibration, microwave extraction, two unique versions of cryogenic extraction, centrifugation, and high pressure mechanical squeezing. We applied these methods to four isotopically unique plant portions (heads, stems, leaves and root crown) of spring wheat (Triticum aestivum L.). The spring wheat was grown under controlled conditions with irrigation inputs of a known isotopic composition. Our results show that the methods of extraction return significantly different plant water isotopic signals. Centrifugation, microwave extraction, direct vapour equilibration, and squeezing returned more enriched results. Both cryogenic systems and squeezing returned more depleted results, depending upon the plant portion extracted. While cryogenic extraction is currently the most widely used method in the literature, our results suggest that direct vapor equilibration method outperforms it in terms of accuracy, sample throughput and replicability. More research is now needed with other plant species (especially woody plants) to see how far the findings from this study could be extended.

Stable isotope ratios in rainfall and water vapour at Bangalore, Southern India during the monsoon period of 2013

NASA Astrophysics Data System (ADS)

Peethambaran, Rahul; Ghosh, Prosenjit

2015-04-01

Rainwater and water vapour were collected during monsoon rainfall from Bangalore station to identifying the signature of moisture sources. Moisture responsible for the rainfall originates from Arabian Sea and Bay of Bengal and advected to the station together with vapour generated from the local . Total no of samples includes 72 for water vapour and 81 for rainwater respectively. The mean difference between water vapour and rainwater was found to be -13.27±2.5 ‰ for δ18O, -100±9 ‰ for δD, which was calculated from monthly mean values of water vapour and rainwater. The most enriched samples of rainwater and water vapour were found during the pre monsoon months which correspond to temperature maximum at the study location. Lighter isotopic ratios were recorded in samples collected during the starting of monsoon showers which goes to further depletion in δ18O during the period of post monsoon. This was mainly due to the change in the prevailing wind direction from southwest to northeast. Local Meteoric Water Line (LMWL) generated for rainwater (d = 7.49 δ 18O + 5.2555, R² = 0.93) equation suggesting enrichment due to evaporation. Local Vapour Line (LVL) (d = 7.5248 δ 18O + 6.6534,R² = 0.8957) indicates the dominance of vapor from local source. The time series of d-xcess of rainwater and water vapor reveals large variability, coinciding with the presence of transported and local sources. It was observed that rainwater and water vapor exhibits higher values indicating re-evaporation from the region. Repetition of this feature demonstrated pattern of moisture recycling in the atmosphere and the contribution of continental evaporation and transpiration. The sensitivity of isotopes to the sudden change in wind direction was documented by an abrupt variations in the isotope values. Such changes in wind patterns were mostly associated with the prevalence of low pressure depression systems during the monsoon periods. Detailed analysis on role of wind patterns and

Critical behaviour and vapour-liquid coexistence of 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ionic liquids via Monte Carlo simulations.

PubMed

Rai, Neeraj; Maginn, Edward J

2012-01-01

Atomistic Monte Carlo simulations are used to compute vapour-liquid coexistence properties of a homologous series of [C(n)mim][NTf2] ionic liquids, with n = 1, 2, 4, 6. Estimates of the critical temperatures range from 1190 K to 1257 K, with longer cation alkyl chains serving to lower the critical temperature. Other quantities such as critical density, critical pressure, normal boiling point, and accentric factor are determined from the simulations. Vapour pressure curves and the temperature dependence of the enthalpy of vapourisation are computed and found to have a weak dependence on the length of the cation alkyl chain. The ions in the vapour phase are predominately in single ion pairs, although a significant number of ions are found in neutral clusters of larger sizes as temperature is increased. It is found that previous estimates of the critical point obtained from extrapolating experimental surface tension data agree reasonably well with the predictions obtained here, but group contribution methods and primitive models of ionic liquids do not capture many of the trends observed in the present study

A sensor of alcohol vapours based on thin polyaniline base film and quartz crystal microbalance.

PubMed

Ayad, Mohamad M; El-Hefnawey, Gad; Torad, Nagy L

2009-08-30

Thin films of polyaniline base, emeraldine base (EB), coating on the quartz crystal microbalance (QCM) electrode were used as a sensitive layer for the detection of a number of primary aliphatic alcohols such as ethanol, methanol, 2-propanol and 1-propanol vapours. The frequency shifts (Deltaf) of the QCM were increased due to the vapour adsorption into the EB film. Deltaf were found to be linearly correlated with the concentrations of alcohols vapour in part per million (ppm). The sensitivity of the sensor was found to be governed by the chemical structure of the alcohol. The sensor shows a good reproducibility and reversibility. The diffusions of different alcohols vapour were studied and the diffusion coefficients (D) were calculated. It is concluded that the diffusion of the vapours into the EB film follows Fickian kinetics.

Vertical structure of stratospheric water vapour trends derived from merged satellite data

PubMed Central

Hegglin, M. I.; Plummer, D. A.; Shepherd, T. G.; Scinocca, J. F.; Anderson, J.; Froidevaux, L.; Funke, B.; Hurst, D.; Rozanov, A.; Urban, J.; von Clarmann, T.; Walker, K. A.; Wang, H. J.; Tegtmeier, S.; Weigel, K.

2017-01-01

Stratospheric water vapour is a powerful greenhouse gas. The longest available record from balloon observations over Boulder, Colorado, USA shows increases in stratospheric water vapour concentrations that cannot be fully explained by observed changes in the main drivers, tropical tropopause temperatures and methane. Satellite observations could help resolve the issue, but constructing a reliable long-term data record from individual short satellite records is challenging. Here we present an approach to merge satellite data sets with the help of a chemistry-climate model nudged to observed meteorology. We use the models' water vapour as a transfer function between data sets that overcomes issues arising from instrument drift and short overlap periods. In the lower stratosphere, our water vapour record extends back to 1988 and water vapour concentrations largely follow tropical tropopause temperatures. Lower and mid-stratospheric long-term trends are negative, and the trends from Boulder are shown not to be globally representative. In the upper stratosphere, our record extends back to 1986 and shows positive long-term trends. The altitudinal differences in the trends are explained by methane oxidation together with a strengthened lower-stratospheric and a weakened upper-stratospheric circulation inferred by this analysis. Our results call into question previous estimates of surface radiative forcing based on presumed global long-term increases in water vapour concentrations in the lower stratosphere. PMID:29263751

Vertical structure of stratospheric water vapour trends derived from merged satellite data.

PubMed

Hegglin, M I; Plummer, D A; Shepherd, T G; Scinocca, J F; Anderson, J; Froidevaux, L; Funke, B; Hurst, D; Rozanov, A; Urban, J; von Clarmann, T; Walker, K A; Wang, H J; Tegtmeier, S; Weigel, K

2014-01-01

Stratospheric water vapour is a powerful greenhouse gas. The longest available record from balloon observations over Boulder, Colorado, USA shows increases in stratospheric water vapour concentrations that cannot be fully explained by observed changes in the main drivers, tropical tropopause temperatures and methane. Satellite observations could help resolve the issue, but constructing a reliable long-term data record from individual short satellite records is challenging. Here we present an approach to merge satellite data sets with the help of a chemistry-climate model nudged to observed meteorology. We use the models' water vapour as a transfer function between data sets that overcomes issues arising from instrument drift and short overlap periods. In the lower stratosphere, our water vapour record extends back to 1988 and water vapour concentrations largely follow tropical tropopause temperatures. Lower and mid-stratospheric long-term trends are negative, and the trends from Boulder are shown not to be globally representative. In the upper stratosphere, our record extends back to 1986 and shows positive long-term trends. The altitudinal differences in the trends are explained by methane oxidation together with a strengthened lower-stratospheric and a weakened upper-stratospheric circulation inferred by this analysis. Our results call into question previous estimates of surface radiative forcing based on presumed global long-term increases in water vapour concentrations in the lower stratosphere.

Enhanced water vapour flow in silica microchannels and interdiffusive water vapour flow through anodic aluminium oxide (AAO) membranes

NASA Astrophysics Data System (ADS)

Lei, Wenwen; McKenzie, David R.

2015-12-01

Enhanced liquid water flows through carbon nanotubes reinvigorated the study of moisture permeation through membranes and micro- and nano-channels. The study of water vapour through micro-and nano-channels has been neglected even though water vapour is as important as liquid water for industry, especially for encapsulation of electronic devices. Here we measure moisture flow rates in silica microchannels and interdiffusive water vapour flows in anodic aluminium oxide (AAO) membrane channels for the first time. We construct theory for the flow rates of the dominant modes of water transport through four previously defined standard configurations and benchmark it against our new measurements. The findings show that measurements of leak behaviour made using other molecules, such as helium, are not reliable. Single phase water vapour flow is overestimated by a helium measurement, while Washburn or capillary flow is underestimated or for all channels when boundary slip applies, to an extent that depends on the slip length for the liquid phase flows.

Atomic origins of water-vapour-promoted alloy oxidation

NASA Astrophysics Data System (ADS)

Luo, Langli; Su, Mao; Yan, Pengfei; Zou, Lianfeng; Schreiber, Daniel K.; Baer, Donald R.; Zhu, Zihua; Zhou, Guangwen; Wang, Yanting; Bruemmer, Stephen M.; Xu, Zhijie; Wang, Chongmin

2018-06-01

The presence of water vapour, intentional or unavoidable, is crucial to many materials applications, such as in steam generators, turbine engines, fuel cells, catalysts and corrosion1-4. Phenomenologically, water vapour has been noted to accelerate oxidation of metals and alloys5,6. However, the atomistic mechanisms behind such oxidation remain elusive. Through direct in situ atomic-scale transmission electron microscopy observations and density functional theory calculations, we reveal that water-vapour-enhanced oxidation of a nickel-chromium alloy is associated with proton-dissolution-promoted formation, migration, and clustering of both cation and anion vacancies. Protons derived from water dissociation can occupy interstitial positions in the oxide lattice, consequently lowering vacancy formation energy and decreasing the diffusion barrier of both cations and anions, which leads to enhanced oxidation in moist environments at elevated temperatures. This work provides insights into water-vapour-enhanced alloy oxidation and has significant implications in other material and chemical processes involving water vapour, such as corrosion, heterogeneous catalysis and ionic conduction.

Atomic origins of water-vapour-promoted alloy oxidation.

PubMed

Luo, Langli; Su, Mao; Yan, Pengfei; Zou, Lianfeng; Schreiber, Daniel K; Baer, Donald R; Zhu, Zihua; Zhou, Guangwen; Wang, Yanting; Bruemmer, Stephen M; Xu, Zhijie; Wang, Chongmin

2018-06-01

The presence of water vapour, intentional or unavoidable, is crucial to many materials applications, such as in steam generators, turbine engines, fuel cells, catalysts and corrosion 1-4 . Phenomenologically, water vapour has been noted to accelerate oxidation of metals and alloys 5,6 . However, the atomistic mechanisms behind such oxidation remain elusive. Through direct in situ atomic-scale transmission electron microscopy observations and density functional theory calculations, we reveal that water-vapour-enhanced oxidation of a nickel-chromium alloy is associated with proton-dissolution-promoted formation, migration, and clustering of both cation and anion vacancies. Protons derived from water dissociation can occupy interstitial positions in the oxide lattice, consequently lowering vacancy formation energy and decreasing the diffusion barrier of both cations and anions, which leads to enhanced oxidation in moist environments at elevated temperatures. This work provides insights into water-vapour-enhanced alloy oxidation and has significant implications in other material and chemical processes involving water vapour, such as corrosion, heterogeneous catalysis and ionic conduction.

The ignitability of petrol vapours and potential for vapour phase explosion by use of TASER® law enforcement electronic control device.

PubMed

Clarke, C; Andrews, S P

2014-12-01

An experimental study was made of the potential of the TASER-X26™ law enforcement electronic control device to ignite petrol vapours if used by an officer to incapacitate a person soaked in petrol, or within a flammable atmosphere containing petrol vapour. Bench scale tests have shown that a wooden mannequin with pig skin covering the chest was a suitable representation of a human target. Full scale tests using the mannequin have shown that the arc from a TASER-X26™ is capable of igniting petrol/air vapours on a petrol-soaked person. Further tests in a 1/5 scale and a full scale compartment have shown that if a TASER is used within a compartment, a petrol vapour explosion (deflagration) may be achieved. It is evident from this research that if used in a flammable vapour rich environment, the device could prove fatal not only to the target but the TASER® operator as well. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

Kinetic studies of BTEX vapour adsorption onto surfaces of calix-4-resorcinarene films

NASA Astrophysics Data System (ADS)

Hassan, A. K.; Ray, A. K.; Nabok, A. V.; Wilkop, T.

2001-10-01

The exposure of spun films of an amphiphilic calix-4-resorcinarene (C-4-RA) derivative to vapours of benzene, toluene, ethylbenzene, and m-xylene (BTEX) has produced a graded response, promising for the development of multisensor arrays. Fast and reversible adsorption of ethylbenzene was associated with changing the refractive index of the sensing layer and is believed to be due to the host-guest interaction between the cavitand C-4-RA molecules and the vapour molecules. Prolonged irradiation of the films with a focused laser beam has resulted in an initial increase of film sensitivity to the different organic vapours.

Detecting vapour bubbles in simulations of metastable water

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

González, Miguel A.; Abascal, Jose L. F.; Valeriani, Chantal, E-mail: christoph.dellago@univie.ac.at, E-mail: cvaleriani@quim.ucm.es

2014-11-14

The investigation of cavitation in metastable liquids with molecular simulations requires an appropriate definition of the volume of the vapour bubble forming within the metastable liquid phase. Commonly used approaches for bubble detection exhibit two significant flaws: first, when applied to water they often identify the voids within the hydrogen bond network as bubbles thus masking the signature of emerging bubbles and, second, they lack thermodynamic consistency. Here, we present two grid-based methods, the M-method and the V-method, to detect bubbles in metastable water specifically designed to address these shortcomings. The M-method incorporates information about neighbouring grid cells to distinguishmore » between liquid- and vapour-like cells, which allows for a very sensitive detection of small bubbles and high spatial resolution of the detected bubbles. The V-method is calibrated such that its estimates for the bubble volume correspond to the average change in system volume and are thus thermodynamically consistent. Both methods are computationally inexpensive such that they can be used in molecular dynamics and Monte Carlo simulations of cavitation. We illustrate them by computing the free energy barrier and the size of the critical bubble for cavitation in water at negative pressure.« less

Non-equilibrium surface tension of the vapour-liquid interface of active Lennard-Jones particles

NASA Astrophysics Data System (ADS)

Paliwal, Siddharth; Prymidis, Vasileios; Filion, Laura; Dijkstra, Marjolein

2017-08-01

We study a three-dimensional system of self-propelled Brownian particles interacting via the Lennard-Jones potential. Using Brownian dynamics simulations in an elongated simulation box, we investigate the steady states of vapour-liquid phase coexistence of active Lennard-Jones particles with planar interfaces. We measure the normal and tangential components of the pressure tensor along the direction perpendicular to the interface and verify mechanical equilibrium of the two coexisting phases. In addition, we determine the non-equilibrium interfacial tension by integrating the difference of the normal and tangential components of the pressure tensor and show that the surface tension as a function of strength of particle attractions is well fitted by simple power laws. Finally, we measure the interfacial stiffness using capillary wave theory and the equipartition theorem and find a simple linear relation between surface tension and interfacial stiffness with a proportionality constant characterized by an effective temperature.

Southern Greenland water vapour isotopic composition at the crossroads of Atlantic and Arctic moisture

NASA Astrophysics Data System (ADS)

Bonne, J. L.; Steen-Larsen, H. C.; Risi, C. M.; Werner, M.; Sodemann, H.; Lacour, J. L.; Fettweis, X.; Cesana, G.; Delmotte, M.; Cattani, O.; Clerbaux, C.; Sveinbjörnsdottir, A. E.; Masson-Delmotte, V.

2014-12-01

Since September 2011, a continuous water vapour isotopic composition monitoring instrument has been remotely operated in Ivittuut (61.21°N, 48.17°W), southern Greenland. Meteorological parameters are monitored and precipitation has been sampled and analysed for isotopic composition, suggesting equilibrium between surface vapour and precipitation. The data depict small summer diurnal variations. δ18O and deuterium excess (d-excess) are generally anti-correlated and show important seasonal variations (with respective amplitudes of 10 and 20 ‰), and large synoptic variations associated to low-pressure systems (typically +5‰ on δ18O and -15‰ on d-excess). The moisture sources, estimated based on Lagrangian back-trajectories, are primarily influenced by the western North Atlantic, and north-eastern American continent. Notable are important seasonal and synoptic shifts of the moisture sources, and sporadic influences of the Arctic or the eastern North Atlantic. Moisture sources variations can be related to changes in water vapour isotopic composition, and the isotopic fingerprints can be attributed to the areas of moisture origins. Isotopic enabled AGCMs nudged to meteorology (LMDZiso, ECHAM5-wiso), despite biases, correctly capture the δ18O changes, but underestimate the d-excess changes. They allow to identify a high correlation between the southern Greenland d-excess and the simulated relative humidity and d-excess in the moisture source region south of Greenland. An extreme high temperature event in July 2012 affecting all Greenland, similar to ice sheet melt events during the medieval periods and one event in 1889 documented by Greenland ice core records, has been analysed regarding water vapour isotopic composition, using remote sensing (IASI) and in situ observations from Bermuda to northern Greenland (NEEM station). Our southern Greenland observations allow to track the water vapour evolution during this event along the moisture transport path

Water Vapour Effects in Mass Measurement

NASA Astrophysics Data System (ADS)

Khélifa, N.

2008-01-01

Water vapour density inside the mass comparator enclosure is a critical parameter whose fluctuations during mass weighing can lead to errors in the determination of an unknown mass. To monitor them, a method using DFB laser diode in the near infrared has been proposed and tested. Preliminary results of our observation of water vapour sorption and de-sorption processes from the walls and the mass standard are reported.

Alcohol vapours sensor based on thin polyaniline salt film and quartz crystal microbalance.

PubMed

Ayad, Mohamad M; Torad, Nagy L

2009-06-15

A sensor based on the quartz crystal microbalance (QCM) technique was developed for detection of a number of primary aliphatic alcohols such as ethanol, methanol, 1-propanol, and 2-propanol vapours. Detection was based on a sensitive and a thin film of polyaniline, emeraldine salt (ES), coated the QCM electrode. The frequency shifts (Delta f) of the QCM were increased due to the vapour absorption into the ES film. The values of Delta f were found to be linearly correlated with the concentrations of alcohols vapour in mg L(-1). The changes in frequency are due to the hydrophilic character of the ES and the electrostatic interaction as well as the type of the alcohol. The sensor shows a good reproducibility and reversibility. The diffusion and diffusion coefficient (D) of different alcohols vapour were determined. It was found that the sensor follows Fickian kinetics.

WALES: water vapour lidar experiment in space

NASA Astrophysics Data System (ADS)

Guerin, F.; Pain, Th.; Palmade, J.-L.; Pailharey, E.; Giraud, D.; Jubineau, F.

2017-11-01

The WAter vapour Lidar Experiment in Space (WALES) mission aims at providing water vapour profiles with high accuracy and vertical resolution through the troposphere and the lower stratosphere on a global scale using an instrument based on Differential Absorption Lidar (DIAL) observation technique, and mounted on an Earth orbiting satellite. This active DIAL technique will also provide data on the cloud coverage by means of the signal reflection on the cloud layers. In DIAL operation, backscatter lidar signals at two wavelengths - at least - are detected. One wavelength (λ ON) is highly absorbed by the species of interest, while the other (λ OFF) is backscattered with minimal absorption. This difference in absorption at the two transmitted wavelengths leads to the determination of the concentration of the species of interest. The DIAL is therefore a dual-wavelength lidar in which the signals detected at the two wavelengths are processed to extract the absolute density of water vapour. The Phase A study performed by ALCATEL Space and their partners under contract of the European Space Agency has led to a credible and innovative concept of instrument, based on a mission performance modelling. The challenge is to foster the scientific return while minimising the development risks and costs of instrument development, in particular the laser transmitter. The paper describes the payload design and the implementation on a low Earth orbiting (LEO) satellite.

WALES: WAter vapour Lidar Experiment in Space

NASA Astrophysics Data System (ADS)

Guerin, F.; Pain, Th.; Palmade, J. L.; Pailharey, E.; Giraud, D.; Jubineau, F.

2004-06-01

The WAter vapour Lidar Experiment in Space (WALES) mission aims at providing water vapour profiles with high accuracy and vertical resolution through the troposphere and the lower stratosphere on a global scale using an instrument based on Differential Absorption Lidar (DIAL) observation technique, and mounted on an Earth orbiting satellite. This active DIAL technique will also provide data on the cloud coverage by means of the signal reflection on the cloud layers. In DIAL operation, backscatter lidar signals at two wavelengths - at least - are detected. One wavelength (λ ON) is highly absorbed by the species of interest, while the other (λ OFF) is backscattered with minimal absorption. This difference in absorption at the two transmitted wavelengths leads to the determination of the concentration of the species of interest. The DIAL is therefore a dual-wavelength lidar in which the signals detected at the two wavelengths are processed to extract the absolute density of water vapour. The Phase A study performed by ALCATEL Space and their partners under contract of the European Space Agency has led to a credible and innovative concept of instrument, based on a mission performance modelling. The challenge is to foster the scientific return while minimising the development risks and costs of instrument development, in particular the laser transmitter. The paper describes the payload design and the implementation on a low Earth orbiting (LEO) satellite.

Seasonally-Active Water on Mars: Vapour, Ice, Adsorbate, and the Possibility of Liquid

NASA Astrophysics Data System (ADS)

Richardson, M. I.

2002-12-01

Seasonally-active water can be defined to include any water reservoir that communicates with other reservoirs on time scales of a year or shorter. It is the interaction of these water reservoirs, under the influence of varying solar radiation and in conjunction with surface and atmospheric temperatures, that determines the phase-stability field for water at the surface, and the distribution of water in various forms below, on, and above the surface. The atmosphere is the critical, dynamical link in this cycling system, and also (fortunately) one of the easiest to observe. Viking and Mars Global Surveyor observations paint a strongly asymmetric picture of the global seasonal water cycle, tied proximately to planetary eccentricity, and the existence of residual ice caps of different composition at the two poles. The northern summer experiences the largest water vapour columns, and is associated with sublimation from the northern residual water ice cap. The southern summer residual carbon dioxide ice cap is cold trap for water. Asymmetry in the water cycle is an unsolved problem. Possible solutions may involve the current timing of perihelion (the water cap resides at the pole experiencing the longer but cooler summer), the trapping of water ice in the northern hemisphere by tropical water ice clouds, and the bias in the annual-average, zonal-mean atmospheric circulation resulting from the zonal-mean difference in the elevation of the northern and southern hemispheres. Adsorbed and frozen water have proven harder to constrain. Recent Odyssey Gamma Ray Spectrometer results suggest substantial ground ice in the mid- and high-latitudes, but this water is likely below the seasonal skin depth for two reasons: the GRS results are best fit with such a model, and GCM models of the water cycle produce dramatically unrealistic atmospheric vapour distributions when such a very near surface, GRS-like distribution is initialized - ultimately removing the water to the northern and

Measurement of the densities of Cu and Ag vapours in a low-voltage switch using the hook method

NASA Astrophysics Data System (ADS)

Lins, Günter

2012-05-01

In a research model of a low-voltage circuit breaker with fixed contacts and windows for optical access, arcs powered by either a high-current transformer or a capacitor bank were initiated by the explosion of tungsten wires. Air at atmospheric pressure was the switching medium. The number densities of neutral silver and copper vapours from contacts and arc runners were measured simultaneously by the hook method using a Mach-Zehnder interferometer combined with a 1 m spectrograph and a gated intensified CCD camera. When an arc current was flowing, a substantial fraction of the metal vapour was ionized, and thus not amenable to a density measurement with the technique chosen. To nevertheless obtain approximate density values, the arc current was forced to zero within 8 to 10 µs at a preset time and measurements were carried out 100 µs after extinction of the arc. At that time the metal vapour was expected to have recombined to a large extent but not yet diffused to the walls in significant amounts. Depending on the current amplitude reached within the arc duration the arc remained anchored to the silver contacts or commutated to the copper arc runners. At a maximum current amplitude of 650 A Ag vapour densities of the order of 1022 m-3 were observed near the anode outweighing the Cu vapour density by a factor of 20. When at 1600 A the arc commutated to the arc runners a Cu vapour density of 8 × 1021 m-3 was reached while the Ag density remained limited to 2 × 1021 m-3.

Solvent vapour monitoring in work space by solid phase micro extraction.

PubMed

Li, K; Santilli, A; Goldthorp, M; Whiticar, S; Lambert, P; Fingas, M

2001-05-07

Solid phase micro extraction (SPME) is a fast, solvent-less alternative to conventional charcoal tube sampling/carbon disulfide extraction for volatile organic compounds (VOC). In this work, SPME was compared to the active sampling technique in a typical lab atmosphere. Two different types of fibre coatings were evaluated for solvent vapour at ambient concentration. A general purpose 100 microm film polydimethylsiloxane (PDMS) fibre was found to be unsuitable for VOC work, despite the thick coating. The mixed-phase carboxen/PDMS fibre was found to be suitable. Sensitivity of the SPME was far greater than charcoal sorbent tube method. Calibration studies using typical solvent such as dichloromethane (DCM), benzene (B) and toluene (T) showed an optimal exposure time of 5 min, with a repeatability of less than 20% for a broad spectrum of organic vapour. Minimum detectable amount for DCM is in the range of 0.01 microg/l (0.003 ppmv). Variation among different fibres was generally within 30% at a vapour concentration of 1 microg DCM/l, which was more than adequate for field monitoring purpose. Adsorption characteristics and calibration procedures were studied. An actual application of SPME was carried out to measure background level of solvent vapour at a bench where DCM was used extensively. Agreement between the SPME and the charcoal sampling method was generally within a factor of two. No DCM concentration was found to be above the regulatory limit of 50 ppmv.

Medical cannabis use in Canada: vapourization and modes of delivery.

PubMed

Shiplo, Samantha; Asbridge, Mark; Leatherdale, Scott T; Hammond, David

2016-10-29

The mode of medical cannabis delivery-whether cannabis is smoked, vapourized, or consumed orally-may have important implications for its therapeutic efficacy and health risks. However, there is very little evidence on current patterns of use among Canadian medical cannabis users, particularly with respect to modes of delivery. The current study examined modes of medical cannabis delivery following regulatory changes in 2014 governing how Canadians access medical cannabis. A total of 364 approved adult Canadian medical cannabis users completed an online cross-sectional survey between April and June 2015. The survey examined patterns of medical cannabis use, modes of delivery used, and reasons for use. Participants were recruited through a convenience sample from nine Health Canada licensed producers. Using a vapourizer was the most popular mode of delivery for medical cannabis (53 %), followed by smoking a joint (47 %). The main reason for using a vapourizer was to reduce negative health consequences associated with smoking. A majority of current vapourizer users reported using a portable vapourizer (67.2 %), followed by a stationary vapourizer (41.7 %), and an e-cigarette or vape pen (19.3 %). Current use of a vapourizer was associated with fewer respiratory symptoms (AOR = 1.28, 95 % CI 1.05-1.56, p = 0.01). The findings suggest an increase in the popularity of vapourizers as the primary mode of delivery among approved medical users. Using vapourizers has the potential to prevent some of the adverse respiratory health consequences associated with smoking and may serve as an effective harm reduction method. Monitoring implications of such current and future changes to medical cannabis regulations may be beneficial to policymakers.

Features in the distribution of middle atmospheric water vapour as observed by groundbased microwave radiometeres in Switzerland and South Korea.

NASA Astrophysics Data System (ADS)

de Wachter, E.; Haefele, A.; Kaempfer, N.; Ka, S.; Oh, J.

2009-04-01

The University of Bern operates two ground based microwave radiometers to measure the water vapour content in the stratosphere and mesosphere. One instrument is located nearby Bern [47°N, 7°E], Switzerland, and has been providing data since 2002 to the "Network for the Detection of Atmospheric Composition Change", NDACC, as well as to the European project GEOmon. The second radiometer has been operational in Seoul [37°N, 126°E], S-Korea, starting November 2006. Both instruments provide water vapour profiles in the altitude range 25 to 70 km. Long-term measurements of middle atmospheric water vapour by ground-based microwave instruments are sparse. These instruments provide long-term stability and high time resolution, so are in this sense ideal for short time-scale variability studies, monitoring long-term trends and validation of satellites. An analysis between these 2-year overlapping datasets of the European and Asian continent can provide valuable input on the distribution of wave patterns. In this study, we present the measurement characteristics of the instruments, and validate our data with water vapour profiles from the Aura/MLS instrument. In addition, we investigate correlations between these two midlatitudinal stations, gathering information on the spatial distribution of water vapour, particularly for pressures from 1 to 0.03 hPa.

Comparisons of xylem sap flow and water vapour flux at the stand level and derivation of canopy conductance for Scots pine

NASA Astrophysics Data System (ADS)

Granier, A.; Biron, P.; Köstner, B.; Gay, L. W.; Najjar, G.

1996-03-01

Simultaneous measurements of xylem sap flow and water vapour flux over a Scots pine ( Pinus sylvestris) forest (Hartheim, Germany), were carried out during the Hartheim Experiment (HartX), an intensive observation campaign of the international programme REKLIP. Sap flow was measured every 30 min using both radial constant heating (Granier, 1985) and two types of Cermak sap flowmeters installed on 24 trees selected to cover a wide range of the diameter classes of the stand (min 8 cm; max 17.5 cm). Available energy was high during the observation period (5.5 to 6.9 mm.day-1), and daily cumulated sap flow on a ground area basis varied between 2.0 and 2.7 mm day-1 depending on climate conditions. Maximum hourly values of sap flow reached 0.33 mm h-1, i.e., 230 W m-2. Comparisons of sap flow with water vapour flux as measured with two OPEC (One Propeller Eddy Correlation, University of Arizona) systems showed a time lag between the two methods, sap flow lagging about 90 min behind vapour flux. After taking into account this time lag in the sap flow data set, a good agreement was found between both methods: sap flow = 0.745* vapour flux, r 2 = 0.86. The difference between the two estimates was due to understory transpiration. Canopy conductance ( g c ) was calculated from sap flow measurements using the reverse form of Penman-Monteith equation and climatic data measured 4 m above the canopy. Variations of g c were well correlated ( r 2 = 0.85) with global radiation ( R) and vapour pressure deficit ( vpd). The quantitative expression for g c = f ( R, vpd) was very similar to that previously found with maritime pine ( Pinus pinaster) in the forest of Les Landes, South Western France.

No sodium in the vapour plumes of Enceladus.

PubMed

Schneider, Nicholas M; Burger, Matthew H; Schaller, Emily L; Brown, Michael E; Johnson, Robert E; Kargel, Jeffrey S; Dougherty, Michele K; Achilleos, Nicholas A

2009-06-25

The discovery of water vapour and ice particles erupting from Saturn's moon Enceladus fuelled speculation that an internal ocean was the source. Alternatively, the source might be ice warmed, melted or crushed by tectonic motions. Sodium chloride (that is, salt) is expected to be present in a long-lived ocean in contact with a rocky core. Here we report a ground-based spectroscopic search for atomic sodium near Enceladus that places an upper limit on the mixing ratio in the vapour plumes orders of magnitude below the expected ocean salinity. The low sodium content of escaping vapour, together with the small fraction of salt-bearing particles, argues against a situation in which a near-surface geyser is fuelled by a salty ocean through cracks in the crust. The lack of observable sodium in the vapour is consistent with a wide variety of alternative eruption sources, including a deep ocean, a freshwater reservoir, or ice. The existing data may be insufficient to distinguish between these hypotheses.

Prediction of vapour-liquid and vapour-liquid-liquid equilibria of nitrogen-hydrocarbon mixtures used in J-T refrigerators

NASA Astrophysics Data System (ADS)

Narayanan, Vineed; Venkatarathnam, G.

2018-03-01

Nitrogen-hydrocarbon mixtures are widely used as refrigerants in J-T refrigerators operating with mixtures, as well as in natural gas liquefiers. The Peng-Robinson equation of state has traditionally been used to simulate the above cryogenic process. Multi parameter Helmholtz energy equations are now preferred for determining the properties of natural gas. They have, however, been used only to predict vapour-liquid equilibria, and not vapour-liquid-liquid equilibria that can occur in mixtures used in cryogenic mixed refrigerant processes. In this paper the vapour-liquid equilibrium of binary mixtures of nitrogen-methane, nitrogen-ethane, nitrogen-propane, nitrogen-isobutane and three component mixtures of nitrogen-methane-ethane and nitrogen-methane-propane have been studied with the Peng-Robinson and the Helmholtz energy equations of state of NIST REFPROP and compared with experimental data available in the literature.

Terminal drought-tolerant pearl millet [Pennisetum glaucum (L.) R. Br.] have high leaf ABA and limit transpiration at high vapour pressure deficit.

PubMed

Kholová, Jana; Hash, C T; Kumar, P Lava; Yadav, Rattan S; Kocová, Marie; Vadez, Vincent

2010-03-01

It was previously shown that pearl millet genotypes carrying a terminal drought tolerance quantitative trait locus (QTL) had a lower transpiration rate (Tr; g cm(-2) d(-1)) under well-watered conditions than sensitive lines. Here experiments were carried out to test whether this relates to leaf abscisic acid (ABA) and Tr concentration at high vapour pressure deficit (VPD), and whether that leads to transpiration efficiency (TE) differences. These traits were measured in tolerant/sensitive pearl millet genotypes, including near-isogenic lines introgressed with a terminal drought tolerance QTL (NIL-QTLs). Most genotypic differences were found under well-watered conditions. ABA levels under well-watered conditions were higher in tolerant genotypes, including NIL-QTLs, than in sensitive genotypes, and ABA did not increase under water stress. Well-watered Tr was lower in tolerant than in sensitive genotypes at all VPD levels. Except for one line, Tr slowed down in tolerant lines above a breakpoint at 1.40-1.90 kPa, with the slope decreasing >50%, whereas sensitive lines showed no change in that Tr response across the whole VPD range. It is concluded that two water-saving (avoidance) mechanisms may operate under well-watered conditions in tolerant pearl millet: (i) a low Tr even at low VPD conditions, which may relate to leaf ABA; and (ii) a sensitivity to higher VPD that further restricts Tr, which suggests the involvement of hydraulic signals. Both traits, which did not lead to TE differences, could contribute to absolute water saving seen in part due to dry weight increase differences. This water saved would become critical for grain filling and deserves consideration in the breeding of terminal drought-tolerant lines.

SI-traceable and dynamic reference gas mixtures for water vapour at polar and high troposphere atmospheric levels

NASA Astrophysics Data System (ADS)

Guillevic, Myriam; Pascale, Céline; Mutter, Daniel; Wettstein, Sascha; Niederhauser, Bernhard

2017-04-01

In the framework of METAS' AtmoChem-ECV project, new facilities are currently being developed to generate reference gas mixtures for water vapour at concentrations measured in the high troposphere and polar regions, in the range 1-20 µmol/mol (ppm). The generation method is dynamic (the mixture is produced continuously over time) and SI-traceable (i.e. the amount of substance fraction in mole per mole is traceable to the definition of SI-units). The generation process is composed of three successive steps. The first step is to purify the matrix gas, nitrogen or synthetic air. Second, this matrix gas is spiked with the pure substance using a permeation technique: a permeation device contains a few grams of pure water in liquid form and loses it linearly over time by permeation through a membrane. In a third step, to reach the desired concentration, the first, high concentration mixture exiting the permeation chamber is then diluted with a chosen flow of matrix gas with one or two subsequent dilution steps. All flows are piloted by mass flow controllers. All parts in contact with the gas mixture are passivated using coated surfaces, to reduce adsorption/desorption processes as much as possible. The mixture can eventually be directly used to calibrate an analyser. The standard mixture produced by METAS' dynamic setup was injected into a chilled mirror from MBW Calibration AG, the designated institute for absolute humidity calibration in Switzerland. The used chilled mirror, model 373LX, is able to measure frost point and sample pressure and therefore calculate the water vapour concentration. This intercomparison of the two systems was performed in the range 4-18 ppm water vapour in synthetic air, at two different pressure levels, 1013.25 hPa and 2000 hPa. We present here METAS' dynamic setup, its uncertainty budget and the first results of the intercomparison with MBW's chilled mirror.

Modelling and intepreting the isotopic composition of water vapour in convective updrafts

NASA Astrophysics Data System (ADS)

Bolot, M.; Legras, B.; Moyer, E. J.

2012-08-01

The isotopic compositions of water vapour and its condensates have long been used as tracers of the global hydrological cycle, but may also be useful for understanding processes within individual convective clouds. We review here the representation of processes that alter water isotopic compositions during processing of air in convective updrafts and present a unified model for water vapour isotopic evolution within undiluted deep convective cores, with a special focus on the out-of-equilibrium conditions of mixed phase zones where metastable liquid water and ice coexist. We use our model to show that a combination of water isotopologue measurements can constrain critical convective parameters including degree of supersaturation, supercooled water content and glaciation temperature. Important isotopic processes in updrafts include kinetic effects that are a consequence of diffusive growth or decay of cloud particles within a supersaturated or subsaturated environment; isotopic re-equilibration between vapour and supercooled droplets, which buffers isotopic distillation; and differing mechanisms of glaciation (droplet freezing vs. the Wegener-Bergeron-Findeisen process). As all of these processes are related to updraft strength, droplet size distribution and the retention of supercooled water, isotopic measurements can serve as a probe of in-cloud conditions of importance to convective processes. We study the sensitivity of the profile of water vapour isotopic composition to differing model assumptions and show how measurements of isotopic composition at cloud base and cloud top alone may be sufficient to retrieve key cloud parameters.

Modelling and interpreting the isotopic composition of water vapour in convective updrafts

NASA Astrophysics Data System (ADS)

Bolot, M.; Legras, B.; Moyer, E. J.

2013-08-01

The isotopic compositions of water vapour and its condensates have long been used as tracers of the global hydrological cycle, but may also be useful for understanding processes within individual convective clouds. We review here the representation of processes that alter water isotopic compositions during processing of air in convective updrafts and present a unified model for water vapour isotopic evolution within undiluted deep convective cores, with a special focus on the out-of-equilibrium conditions of mixed-phase zones where metastable liquid water and ice coexist. We use our model to show that a combination of water isotopologue measurements can constrain critical convective parameters, including degree of supersaturation, supercooled water content and glaciation temperature. Important isotopic processes in updrafts include kinetic effects that are a consequence of diffusive growth or decay of cloud particles within a supersaturated or subsaturated environment; isotopic re-equilibration between vapour and supercooled droplets, which buffers isotopic distillation; and differing mechanisms of glaciation (droplet freezing vs. the Wegener-Bergeron-Findeisen process). As all of these processes are related to updraft strength, particle size distribution and the retention of supercooled water, isotopic measurements can serve as a probe of in-cloud conditions of importance to convective processes. We study the sensitivity of the profile of water vapour isotopic composition to differing model assumptions and show how measurements of isotopic composition at cloud base and cloud top alone may be sufficient to retrieve key cloud parameters.

Intercomparison of atmospheric water vapour measurements at a Canadian High Arctic site

NASA Astrophysics Data System (ADS)

Weaver, Dan; Strong, Kimberly; Schneider, Matthias; Rowe, Penny M.; Sioris, Chris; Walker, Kaley A.; Mariani, Zen; Uttal, Taneil; McElroy, C. Thomas; Vömel, Holger; Spassiani, Alessio; Drummond, James R.

2017-08-01

Water vapour is a critical component of the Earth system. Techniques to acquire and improve measurements of atmospheric water vapour and its isotopes are under active development. This work presents a detailed intercomparison of water vapour total column measurements taken between 2006 and 2014 at a Canadian High Arctic research site (Eureka, Nunavut). Instruments include radiosondes, sun photometers, a microwave radiometer, and emission and solar absorption Fourier transform infrared (FTIR) spectrometers. Close agreement is observed between all combination of datasets, with mean differences ≤ 1.0 kg m-2 and correlation coefficients ≥ 0.98. The one exception in the observed high correlation is the comparison between the microwave radiometer and a radiosonde product, which had a correlation coefficient of 0.92.A variety of biases affecting Eureka instruments are revealed and discussed. A subset of Eureka radiosonde measurements was processed by the Global Climate Observing System (GCOS) Reference Upper Air Network (GRUAN) for this study. Comparisons reveal a small dry bias in the standard radiosonde measurement water vapour total columns of approximately 4 %. A recently produced solar absorption FTIR spectrometer dataset resulting from the MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) retrieval technique is shown to offer accurate measurements of water vapour total columns (e.g. average agreement within -5.2 % of GRUAN and -6.5 % of a co-located emission FTIR spectrometer). However, comparisons show a small wet bias of approximately 6 % at the high-latitude Eureka site. In addition, a new dataset derived from Atmospheric Emitted Radiance Interferometer (AERI) measurements is shown to provide accurate water vapour measurements (e.g. average agreement was within 4 % of GRUAN), which usefully enables measurements to be taken during day and night (especially valuable during polar night).

Effect of drilling fluid systems and temperature on oil mist and vapour levels generated from shale shaker.

PubMed

Steinsvåg, Kjersti; Galea, Karen S; Krüger, Kirsti; Peikli, Vegard; Sánchez-Jiménez, Araceli; Sætvedt, Esther; Searl, Alison; Cherrie, John W; van Tongeren, Martie

2011-05-01

Workers in the drilling section of the offshore petroleum industry are exposed to air pollutants generated by drilling fluids. Oil mist and oil vapour concentrations have been measured in the drilling fluid processing areas for decades; however, little work has been carried out to investigate exposure determinants such as drilling fluid viscosity and temperature. A study was undertaken to investigate the effect of two different oil-based drilling fluid systems and their temperature on oil mist, oil vapour, and total volatile organic compounds (TVOC) levels in a simulated shale shaker room at a purpose-built test centre. Oil mist and oil vapour concentrations were sampled simultaneously using a sampling arrangement consisting of a Millipore closed cassette loaded with glass fibre and cellulose acetate filters attached to a backup charcoal tube. TVOCs were measured by a PhoCheck photo-ionization detector direct reading instrument. Concentrations of oil mist, oil vapour, and TVOC in the atmosphere surrounding the shale shaker were assessed during three separate test periods. Two oil-based drilling fluids, denoted 'System 2.0' and 'System 3.5', containing base oils with a viscosity of 2.0 and 3.3-3.7 mm(2) s(-1) at 40°C, respectively, were used at temperatures ranging from 40 to 75°C. In general, the System 2.0 yielded low oil mist levels, but high oil vapour concentrations, while the opposite was found for the System 3.5. Statistical significant differences between the drilling fluid systems were found for oil mist (P = 0.025),vapour (P < 0.001), and TVOC (P = 0.011). Increasing temperature increased the oil mist, oil vapour, and TVOC levels. Oil vapour levels at the test facility exceeded the Norwegian oil vapour occupational exposure limit (OEL) of 30 mg m(-3) when the drilling fluid temperature was ≥50°C. The practice of testing compliance of oil vapour exposure from drilling fluids systems containing base oils with viscosity of ≤2.0 mm(2) s(-1) at 40�

Spool-Valve Pressure-Difference Regulator

NASA Technical Reports Server (NTRS)

Grasso, A. P.

1983-01-01

Valves maintain preset pressure difference between gas flows. Two spool valves connected by shaft move back and forth in response to changes in pressure in oxygen and hydrogen chambers. Spool-valve assembly acts to restore pressures to preset difference. By eliminating diaphragms, pressure exerted directly on external end of spool valve; however, forces and therefore sensitivity of assembly are reduced.

Vapour pressure deficit control in relation to water transport and water productivity in greenhouse tomato production during summer

PubMed Central

Zhang, Dalong; Du, Qingjie; Zhang, Zhi; Jiao, Xiaocong; Song, Xiaoming; Li, Jianming

2017-01-01

Although atmospheric vapour pressure deficit (VPD) has been widely recognized as the evaporative driving force for water transport, the potential to reduce plant water consumption and improve water productivity by regulating VPD is highly uncertain. To bridge this gap, water transport in combination with plant productivity was examined in tomato (Solanum lycopersicum L.) plants grown under contrasting VPD gradients. The driving force for water transport was substantially reduced in low-VPD treatment, which consequently decreased water loss rate and moderated plant water stress: leaf desiccation, hydraulic limitation and excessive negative water potential were prevented by maintaining water balance. Alleviation in water stress by reducing VPD sustained stomatal function and photosynthesis, with concomitant improvements in biomass and fruit production. From physiological perspectives, suppression of the driving force and water flow rate substantially reduced cumulative transpiration by 19.9%. In accordance with physiological principles, irrigation water use efficiency as criterions of biomass and fruit yield in low-VPD treatment was significantly increased by 36.8% and 39.1%, respectively. The reduction in irrigation was counterbalanced by input of fogging water to some extent. Net water saving can be increased by enabling greater planting densities and improving the evaporative efficiency of the mechanical system. PMID:28266524

Stomatal sensitivity to vapour pressure deficit relates to climate of origin in Eucalyptus species.

PubMed

Bourne, Aimee E; Haigh, Anthony M; Ellsworth, David S

2015-03-01

Selecting plantation species to balance water use and production requires accurate models for predicting how species will tolerate and respond to environmental conditions. Although interspecific variation in water use occurs, species-specific parameters are rarely incorporated into physiologically based models because often the appropriate species parameters are lacking. To determine the physiological control over water use in Eucalyptus, five stands of Eucalyptus species growing in a common garden were measured for sap flux rates and their stomatal response to vapour pressure deficit (D) was assessed. Maximal canopy conductance and whole-canopy stomatal sensitivity to D and reduced water availability were lower in species originating from more arid climates of origin than those from humid climates. Species from humid climates showed a larger decline in maximal sap flux density (JSmax) with reduced water availability, and a lower D at which stomatal closure occurred than species from more arid climates, implying larger sensitivity to water availability and D in these species. We observed significant (P < 0.05) correlations of species climate of origin with mean vessel diameter (R(2) = 0.90), stomatal sensitivity to D (R(2) = 0.83) and the size of the decline in JSmax to restricted water availability (R(2) = 0.94). Thus aridity of climate of origin appears to have a selective role in constraining water-use response among the five Eucalyptus plantation species. These relationships emphasize that within this congeneric group of species, climate aridity constrains water use. These relationships have implications for species choices for tree plantation success against drought-induced losses and the ability to manage Eucalyptus plantations against projected changes in water availability and evaporation in the future. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Water vapour fluxes trends on different time scales and their relationship with weather and soil drivers: a case study from a dehesa site in South Spain

NASA Astrophysics Data System (ADS)

Polo, María José; Egüen, Marta; Andreu, Ana; Carpintero, Elisabet; Gómez-Giráldez, Pedro; Patrocinio González-Dugo, María

2017-04-01

Water vapour fluxes between the soil surface and the atmosphere constitute one of the most important components of the water cycle in the continental areas. Their regime directly affect the availability of water to plants, water storage in surface bodies, air humidity in the boundary layer, snow persistence… among others, and the list of indirectly affected processes comprises a large number of components. Water potential or wetness gradients are some of the main drivers of water vapour fluxes to the atmosphere; soil humidity is usually monitored as key variable in many hydrological and environmental studies, and its estimated series are used to calibrate and validate the modelling of certain hydrological processes. However, such results may differ when water fluxes are used instead of water state variables, such as humidity. This work shows the analysis of high resolution water vapour fluxes series from a dehesa area in South Spain where a complete energy and water fluxes/variables monitoring site has been operating for the last four years. The results include pasture and tree vegetated control points. The daily water budget calculation on both types of sites has been performed from weather and energy fluxes measurements, and soil moisture measurements, and the results have been aggregated on a weekly, monthly and seasonal basis. Comparison between observed trends of soil moisture and calculated trends of water vapour fluxes is included to show the differences arising in terms of the regime of the dominant weather variables in this type of ecosystems. The results identify significant thresholds for each weather variable driver and highlight the importance of the wind regime, which is the somehow forgotten variable in future climate impacts on hydrology. Further work is being carried out to assess water cycle potential trends under future climate conditions and their impacts on the vegetation in dehesa ecosystems.

Remediation of sandy soils contaminated with hydrocarbons and halogenated hydrocarbons by soil vapour extraction.

PubMed

Albergaria, José Tomás; Alvim-Ferraz, Maria da Conceição M; Delerue-Matos, Cristina

2012-08-15

This paper presents the study of the remediation of sandy soils containing six of the most common contaminants (benzene, toluene, ethylbenzene, xylene, trichloroethylene and perchloroethylene) using soil vapour extraction (SVE). The influence of soil water content on the process efficiency was evaluated considering the soil type and the contaminant. For artificially contaminated soils with negligible clay contents and natural organic matter it was concluded that: (i) all the remediation processes presented efficiencies above 92%; (ii) an increase of the soil water content led to a more time-consuming remediation; (iii) longer remediation periods were observed for contaminants with lower vapour pressures and lower water solubilities due to mass transfer limitations. Based on these results an easy and relatively fast procedure was developed for the prediction of the remediation times of real soils; 83% of the remediation times were predicted with relative deviations below 14%. Copyright © 2012 Elsevier Ltd. All rights reserved.

Terminal drought-tolerant pearl millet [Pennisetum glaucum (L.) R. Br.] have high leaf ABA and limit transpiration at high vapour pressure deficit

PubMed Central

Kholová, Jana; Hash, C. T.; Kumar, P. Lava; Yadav, Rattan S.; Kočová, Marie; Vadez, Vincent

2010-01-01

It was previously shown that pearl millet genotypes carrying a terminal drought tolerance quantitative trait locus (QTL) had a lower transpiration rate (Tr; g cm−2 d−1) under well-watered conditions than sensitive lines. Here experiments were carried out to test whether this relates to leaf abscisic acid (ABA) and Tr concentration at high vapour pressure deficit (VPD), and whether that leads to transpiration efficiency (TE) differences. These traits were measured in tolerant/sensitive pearl millet genotypes, including near-isogenic lines introgressed with a terminal drought tolerance QTL (NIL-QTLs). Most genotypic differences were found under well-watered conditions. ABA levels under well-watered conditions were higher in tolerant genotypes, including NIL-QTLs, than in sensitive genotypes, and ABA did not increase under water stress. Well-watered Tr was lower in tolerant than in sensitive genotypes at all VPD levels. Except for one line, Tr slowed down in tolerant lines above a breakpoint at 1.40–1.90 kPa, with the slope decreasing >50%, whereas sensitive lines showed no change in that Tr response across the whole VPD range. It is concluded that two water-saving (avoidance) mechanisms may operate under well-watered conditions in tolerant pearl millet: (i) a low Tr even at low VPD conditions, which may relate to leaf ABA; and (ii) a sensitivity to higher VPD that further restricts Tr, which suggests the involvement of hydraulic signals. Both traits, which did not lead to TE differences, could contribute to absolute water saving seen in part due to dry weight increase differences. This water saved would become critical for grain filling and deserves consideration in the breeding of terminal drought-tolerant lines. PMID:20142425

Oil mist and vapour concentrations from drilling fluids: inter- and intra-laboratory comparison of chemical analyses.

PubMed

Galea, Karen S; Searl, Alison; Sánchez-Jiménez, Araceli; Woldbæk, Torill; Halgard, Kristin; Thorud, Syvert; Steinsvåg, Kjersti; Krüger, Kirsti; Maccalman, Laura; Cherrie, John W; van Tongeren, Martie

2012-01-01

There are no recognized analytical methods for measuring oil mist and vapours arising from drilling fluids used in offshore petroleum drilling industry. To inform the future development of improved methods of analysis for oil mist and vapours this study assessed the inter- and intra-laboratory variability in oil mist and vapour analysis. In addition, sample losses during transportation and storage were assessed. Replicate samples for oil mist and vapour were collected using the 37-mm Millipore closed cassette and charcoal tube assembly. Sampling was conducted in a simulated shale shaker room, similar to that found offshore for processing drilling fluids. Samples were analysed at two different laboratories, one in Norway and one in the UK. Oil mist samples were analysed using Fourier transform infrared spectroscopy (FTIR), while oil vapour samples were analysed by gas chromatography (GC). The comparison of replicate samples showed substantial within- and between-laboratory variability in reported oil mist concentrations. The variability in oil vapour results was considerably reduced compared to oil mist, provided that a common method of calibration and quantification was adopted. The study also showed that losses can occur during transportation and storage of samples. There is a need to develop a harmonized method for the quantification of oil mist on filter and oil vapour on charcoal supported by a suitable proficiency testing scheme for laboratories involved in the analysis of occupational hygiene samples for the petroleum industry. The uncertainties in oil mist and vapour measurement have substantial implications in relation to compliance with occupational exposure limits and also in the reliability of any exposure-response information reported in epidemiological studies.

Vapour-phase method in the synthesis of polymer-ibuprofen sodium-silica gel composites.

PubMed

Kierys, Agnieszka; Krasucka, Patrycja; Grochowicz, Marta

2017-11-01

The study discusses the synthesis of polymer-silica composites comprising water soluble drug (ibuprofen sodium, IBS). The polymers selected for this study were poly(TRIM) and poly(HEMA- co -TRIM) produced in the form of permanently porous beads via the suspension-emulsion polymerization method. The acid and base set ternary composites were prepared by the saturation of the solid dispersions of drug (poly(TRIM)-IBS and/or poly(HEMA- co -TRIM)-IBS) with TEOS, and followed by their exposition to the vapour mixture of water and ammonia, or water and hydrochloric acid, at autogenous pressure. The conducted analyses reveal that the internal structure and total porosity of the resulting composites strongly depend on the catalyst which was used for silica precursor gelation. The parameters characterizing the porosity of both of the acid set composites are much lower than the parameters of the base set composites. Moreover, the basic catalyst supplied in the vapour phase does not affect the ibuprofen sodium molecules, whereas the acid one causes transformation of the ibuprofen sodium into the sodium chloride and a derivative of propanoic acid, which is poorly water soluble. The release profiles of ibuprofen sodium from composites demonstrate that there are differences in the rate and efficiency of drug desorption from them. They are mainly affected by the chemical character of the polymeric carrier but are also associated with the restricted swelling of the composites in the buffer solution after precipitation of silica gel.

UTLS water vapour from SCIAMACHY limb measurementsV3.01 (2002-2012).

PubMed

Weigel, K; Rozanov, A; Azam, F; Bramstedt, K; Damadeo, R; Eichmann, K-U; Gebhardt, C; Hurst, D; Kraemer, M; Lossow, S; Read, W; Spelten, N; Stiller, G P; Walker, K A; Weber, M; Bovensmann, H; Burrows, J P

2016-01-01

The SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) aboard the Envisat satellite provided measurements from August 2002 until April 2012. SCIAMACHY measured the scattered or direct sunlight using different observation geometries. The limb viewing geometry allows the retrieval of water vapour at about 10-25 km height from the near-infrared spectral range (1353-1410 nm). These data cover the upper troposphere and lower stratosphere (UTLS), a region in the atmosphere which is of special interest for a variety of dynamical and chemical processes as well as for the radiative forcing. Here, the latest data version of water vapour (V3.01) from SCIAMACHY limb measurements is presented and validated by comparisons with data sets from other satellite and in situ measurements. Considering retrieval tests and the results of these comparisons, the V3.01 data are reliable from about 11 to 23 km and the best results are found in the middle of the profiles between about 14 and 20 km. Above 20 km in the extra tropics V3.01 is drier than all other data sets. Additionally, for altitudes above about 19 km, the vertical resolution of the retrieved profile is not sufficient to resolve signals with a short vertical structure like the tape recorder. Below 14 km, SCIAMACHY water vapour V3.01 is wetter than most collocated data sets, but the high variability of water vapour in the troposphere complicates the comparison. For 14-20 km height, the expected errors from the retrieval and simulations and the mean differences to collocated data sets are usually smaller than 10 % when the resolution of the SCIAMACHY data is taken into account. In general, the temporal changes agree well with collocated data sets except for the Northern Hemisphere extratropical stratosphere, where larger differences are observed. This indicates a possible drift in V3.01 most probably caused by the incomplete treatment of volcanic aerosols in the retrieval. In all other regions a

FAST TRACK COMMUNICATION: Metal vapour causes a central minimum in arc temperature in gas-metal arc welding through increased radiative emission

NASA Astrophysics Data System (ADS)

Schnick, M.; Füssel, U.; Hertel, M.; Spille-Kohoff, A.; Murphy, A. B.

2010-01-01

A computational model of the argon arc plasma in gas-metal arc welding (GMAW) that includes the influence of metal vapour from the electrode is presented. The occurrence of a central minimum in the radial distributions of temperature and current density is demonstrated. This is in agreement with some recent measurements of arc temperatures in GMAW, but contradicts other measurements and also the predictions of previous models, which do not take metal vapour into account. It is shown that the central minimum is a consequence of the strong radiative emission from the metal vapour. Other effects of the metal vapour, such as the flux of relatively cold vapour from the electrode and the increased electrical conductivity, are found to be less significant. The different effects of metal vapour in gas-tungsten arc welding and GMAW are explained.

Claims in vapour device (e-cigarette) regulation: A Narrative Policy Framework analysis.

PubMed

O'Leary, Renée; Borland, Ron; Stockwell, Tim; MacDonald, Marjorie

2017-06-01

The electronic cigarette or e-cigarette (vapour device) is a consumer product undergoing rapid growth, and governments have been adopting regulations on the sale of the devices and their nicotine liquids. Competing claims about vapour devices have ignited a contentious debate in the public health community. What claims have been taken up in the state arena, and how have they possibly influenced regulatory outcomes? This study utilized Narrative Policy Framework to analyze the claims made about vapour devices in legislation recommendation reports from Queensland Australia, Canada, and the European Union, and the 2016 deeming rule legislation from the United States, and examined the claims and the regulatory outcomes in these jurisdictions. The vast majority of claims in the policy documents represented vapour devices as a threat: an unsafe product harming the health of vapour device users, a gateway product promoting youth tobacco uptake, and a quasi-tobacco product impeding tobacco control. The opportunity for vapour devices to promote cessation or reduce exposure to toxins was very rarely presented, and these positive claims were not discussed at all in two of the four documents studied. The dominant claims of vapour devices as a public health threat have supported regulations that have limited their potential as a harm reduction strategy. Future policy debates should evaluate the opportunities for vapour devices to decrease the health and social burdens of the tobacco epidemic. Copyright © 2017 Elsevier B.V. All rights reserved.

Initial evaluation of airborne water vapour measurements by the IAGOS-GHG CRDS system

NASA Astrophysics Data System (ADS)

Filges, Annette; Gerbig, Christoph; Smit, Herman G. J.; Krämer, Martina; Spelten, Nicole

2013-04-01

Accurate and reliable airborne measurements of water vapour are still a challenge. Presently, no airborne humidity sensor exists that covers the entire range of water vapour content between the surface and the upper troposphere/lower stratosphere (UT/LS) region with sufficient accuracy and time resolution. Nevertheless , these data are a pre-requisite to study the underlying processes in the chemistry and physics of the atmosphere. The DENCHAR project (Development and Evaluation of Novel Compact Hygrometer for Airborne Research) addresses this deficit by developing and characterizing novel or improved compact airborne hygrometers for different airborne applications within EUFAR (European Facility for Airborne Research). As part of the DENCHAR inter-comparison campaign in Hohn (Germany), 23 May - 1 June 2011, a commercial gas analyzer (G2401-m, Picarro Inc.,US), based on cavity ring-down spectroscopy (CRDS), was installed on a Learjet to measure water vapour, CO2, CH4 and CO. The CRDS components are identical to those chosen for integration aboard commercial airliner within IAGOS (In-service Aircraft for a Global Observing System). Thus the campaign allowed for the initial assessment validation of the long-term IAGOS H2O measurements by CRDS against reference instruments with a long performance record (FISH, the Fast In-situ Stratospheric Hygrometer, and CR2 frostpoint hygrometer, both research centre Juelich). The inlet system, a one meter long 1/8" FEP-tube connected to a Rosemount TAT housing (model 102BX, deiced) installed on a window plate of the aircraft, was designed to eliminate sampling of larger aerosols, ice particles, and water droplets, and provides about 90% of ram-pressure. In combination with a lowered sample flow of 0.1 slpm (corresponding to a 4 second response time), this ensured a fully controlled sample pressure in the cavity of 140 torr throughout an aircraft altitude operating range up to 12.5 km without the need of an upstream sampling pump

Preparation of fungal conidia impacts their susceptibility to inactivation by ethanol vapours.

PubMed

Dao, Thien; Dantigny, Philippe

2009-11-15

A common protocol employed for the preparation of conidia employs flooding a fungal colony grown on semi-solid media under optimum conditions with an aqueous solution. In contrast, conidia produced in a natural environment are usually not hydrated when disseminated in air and can be produced under water stress. In order to simulate the latter conditions, cultures were grown at different water activities and conidia were dry-harvested on the lid by turning the dishes upside-down then gently tapping the bottom of the box. This study aimed at assessing the effect of the preparation of fungal conidia on their inactivation by ethanol vapours. Firstly ethanol vapours (either 0.30 or 0.45 kPa) were applied to conidia obtained from the standardised protocol and to dry-harvested conidia for some species of Penicillium. While all dry-harvested conidia remained viable after 24 h of treatment, about 1.0, 3.5 and 2.5 log(10) reductions were observed for hydrated conidia of Penicillium chrysogenum, Penicillium digitatum and Penicillium italicum respectively. Secondly ethanol vapours (0.67 kPa) were applied to dry-harvested conidia obtained from cultures grown at 0.99 a(w) and at reduced water activities. For all species, the susceptibility to ethanol vapours of conidia obtained at 0.99 a(w) was significantly greater than that of conidia obtained at reduced water activities. Conidia produced in a natural environment under non-optimal conditions would be much more resistant to ethanol vapours than those produced in the laboratory. This phenomenon may be due to a reduced intracellular water activity of dry-harvested conidia.

Leidenfrost vapour layer moderation of the drag crisis and trajectories of superhydrophobic and hydrophilic spheres falling in water.

PubMed

Vakarelski, Ivan U; Chan, Derek Y C; Thoroddsen, Sigurdur T

2014-08-21

We investigate the dynamic effects of a Leidenfrost vapour layer sustained on the surface of heated steel spheres during free fall in water. We find that a stable vapour layer sustained on the textured superhydrophobic surface of spheres falling through 95 °C water can reduce the hydrodynamic drag by up to 75% and stabilize the sphere trajectory for the Reynolds number between 10(4) and 10(6), spanning the drag crisis in the absence of the vapour layer. For hydrophilic spheres under the same conditions, the transition to drag reduction and trajectory stability occurs abruptly at a temperature different from the static Leidenfrost point. The observed drag reduction effects are attributed to the disruption of the viscous boundary layer by the vapour layer whose thickness depends on the water temperature. Both the drag reduction and the trajectory stabilization effects are expected to have significant implications for development of sustainable vapour layer based technologies.

Atrial and ventricular septal changes in ethanol vapour exposed chick embryos.

PubMed

Kamran, Kiran; Khan, Muhammad Yunus; Minhas, Liaqat Ali

2015-03-01

To study the effects of ethanol vapour exposure on development of atrial and ventricular septa of chick embryo. The experimental study was conducted at the College of Physicians and Surgeons, Islamabad, from 2006 to 2007. The experimental and control groups were further divided into three subgroups based on the day of sacrifice. The experimental group was exposed to ethanol vapours produced in a specially-designed vapour chamber and then compared with age-matched controls. There were 90 eggs in each of the two groups. The development of inter-ventricular septum completed at day 7 of development in chick embryo. Ethanol vapour exposure produced a small discontinuity at day 10 of development in a chick embryo which may be labelled as ventricular septal defect since ventricular development is completed by day 7. Interatrial septum formed till day 7 with small perforations which persisted till hatching. Ethanol vapour exposure may lead to ventricular septal defect.

Sensing response of copper phthalocyanine salt dispersed glass with organic vapours

NASA Astrophysics Data System (ADS)

Ridhi, R.; Sachdeva, Sheenam; Saini, G. S. S.; Tripathi, S. K.

2016-05-01

Copper Phthalocyanine and other Metal Phthalocyanines are very flexible and tuned easily to modify their structural, spectroscopic, optical and electrical properties by either functionalizing them with various substituent groups or by replacing or adding a ligand to the central metal atom in the phthalocyanine ring and accordingly can be made sensitive and selective to various organic species or gaseous vapours. In the present work, we have dispersed Copper Phthalocyanine Salt (CuPcS) in sol-gel glass form using chemical route sol-gel method and studied its sensing mechanism with organic vapours like methanol and benzene and found that current increases onto their exposure with vapours. A variation in the activation energies was also observed with exposure of vapours.

CO 2-fluxing collapses metal mobility in magmatic vapour

DOE PAGES

van Hinsberg, V. J.; Berlo, K.; Migdisov, A. A.; ...

2016-05-18

Magmatic systems host many types of ore deposits, including world-class deposits of copper and gold. Magmas are commonly an important source of metals and ore-forming fluids in these systems. In many magmatic-hydrothermal systems, low-density aqueous fluids, or vapours, are significant metal carriers. Such vapours are water-dominated shallowly, but fluxing of CO 2-rich vapour exsolved from deeper magma is now recognised as ubiquitous during open-system magma degassing. Furthermore, we show that such CO 2-fluxing leads to a sharp drop in element solubility, up to a factor of 10,000 for Cu, and thereby provides a highly efficient, but as yet unrecognised mechanismmore » for metal deposition.« less

Sensing response of copper phthalocyanine salt dispersed glass with organic vapours

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

Ridhi, R.; Sachdeva, Sheenam; Saini, G. S. S.

2016-05-06

Copper Phthalocyanine and other Metal Phthalocyanines are very flexible and tuned easily to modify their structural, spectroscopic, optical and electrical properties by either functionalizing them with various substituent groups or by replacing or adding a ligand to the central metal atom in the phthalocyanine ring and accordingly can be made sensitive and selective to various organic species or gaseous vapours. In the present work, we have dispersed Copper Phthalocyanine Salt (CuPcS) in sol-gel glass form using chemical route sol-gel method and studied its sensing mechanism with organic vapours like methanol and benzene and found that current increases onto their exposuremore » with vapours. A variation in the activation energies was also observed with exposure of vapours.« less

Analysis of Water Vapour Flux Between Alpine Wetlands Underlying the Surface and Atmosphere in the Source Region of the Yellow River

NASA Astrophysics Data System (ADS)

Xie, Y.; Wen, J.; Liu, R.; Wang, X.; JIA, D.

2017-12-01

Wetland underlying surface is sensitive to climate change. Analysis of the degree of coupling between wetlands and the atmosphere and a quantitative assessment of how environmental factors influence latent heat flux have considerable scientific significance. Previous studies, which focused on the forest, grassland and farmland ecosystems, lack research on the alpine wetlands. In addition, research on the environmental control mechanism of latent heat flux is still qualitative and lacks quantitative evaluations and calculations. Using data from the observational tests of the Maduo Observatory of Climate and Environment of the Northwest Institute of Eco-Environment and Resource, CAS, from June 1 to August 31, 2014, this study analysed the time-varying characteristics and causes of the degree of coupling between alpine wetlands underlying surface and the atmosphere and quantitatively calculated the influences of different environmental factors (solar radiation and vapour pressure deficit) on latent heat flux. The results were as follows: Due to the diurnal variations of solar radiation and wind speed, the diurnal variations of the Ω factor present a trend in which the Ω factor are small in the morning and large in the evening. Due to the vegetation growing cycle, the seasonal variations of the Ω factor present a reverse "U" trend . These trends are similar to the diurnal and seasonal variations of the absolute control exercised by solar radiation over the latent heat flux. This conforms to omega theory. The values for average absolute atmospheric factor (surface factor or total ) control exercised by solar radiation and water vapour pressure are 0.20 (0.02 or 0.22 ) and 0.005 (-0.07 or -0.06) W·m-2·Pa-1, respectively.. Generally speaking, solar radiation and water vapour pressure deficit exert opposite forces on the latent heat flux. The average Ω factor is high during the vegetation growing season, with a value of 0.38, and the degree of coupling between the

UTLS water vapour from SCIAMACHY limb measurementsV3.01 (2002–2012)

PubMed Central

Weigel, K.; Rozanov, A.; Azam, F.; Bramstedt, K.; Damadeo, R.; Eichmann, K.-U.; Gebhardt, C.; Hurst, D.; Kraemer, M.; Lossow, S.; Read, W.; Spelten, N.; Stiller, G. P.; Walker, K. A.; Weber, M.; Bovensmann, H.; Burrows, J. P.

2017-01-01

The SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) aboard the Envisat satellite provided measurements from August 2002 until April 2012. SCIAMACHY measured the scattered or direct sunlight using different observation geometries. The limb viewing geometry allows the retrieval of water vapour at about 10–25 km height from the near-infrared spectral range (1353–1410 nm). These data cover the upper troposphere and lower stratosphere (UTLS), a region in the atmosphere which is of special interest for a variety of dynamical and chemical processes as well as for the radiative forcing. Here, the latest data version of water vapour (V3.01) from SCIAMACHY limb measurements is presented and validated by comparisons with data sets from other satellite and in situ measurements. Considering retrieval tests and the results of these comparisons, the V3.01 data are reliable from about 11 to 23 km and the best results are found in the middle of the profiles between about 14 and 20 km. Above 20 km in the extra tropics V3.01 is drier than all other data sets. Additionally, for altitudes above about 19 km, the vertical resolution of the retrieved profile is not sufficient to resolve signals with a short vertical structure like the tape recorder. Below 14 km, SCIAMACHY water vapour V3.01 is wetter than most collocated data sets, but the high variability of water vapour in the troposphere complicates the comparison. For 14–20 km height, the expected errors from the retrieval and simulations and the mean differences to collocated data sets are usually smaller than 10 % when the resolution of the SCIAMACHY data is taken into account. In general, the temporal changes agree well with collocated data sets except for the Northern Hemisphere extratropical stratosphere, where larger differences are observed. This indicates a possible drift in V3.01 most probably caused by the incomplete treatment of volcanic aerosols in the retrieval. In all other regions

A water vapour monitor at Paranal Observatory

NASA Astrophysics Data System (ADS)

Kerber, Florian; Rose, Thomas; Chacón, Arlette; Cuevas, Omar; Czekala, Harald; Hanuschik, Reinhard; Momany, Yazan; Navarrete, Julio; Querel, Richard R.; Smette, Alain; van den Ancker, Mario E.; Cure, Michel; Naylor, David A.

2012-09-01

We present the performance characteristics of a water vapour monitor that has been permanently deployed at ESO's Paranal observatory as a part of the VISIR upgrade project. After a careful analysis of the requirements and an open call for tender, the Low Humidity and Temperature Profiling microwave radiometer (LHATPRO), manufactured by Radiometer Physics GmbH (RPG), has been selected. The unit measures several channels across the strong water vapour emission line at 183 GHz, necessary for resolving the low levels of precipitable water vapour (PWV) that are prevalent on Paranal (median ~2.5 mm). The unit comprises the above humidity profiler (183-191 GHz), a temperature profiler (51-58 GHz), and an infrared radiometer (~10 μm) for cloud detection. The instrument has been commissioned during a 2.5 week period in Oct/Nov 2011, by comparing its measurements of PWV and atmospheric profiles with the ones obtained by 22 radiosonde balloons. In parallel an IR radiometer (Univ. Lethbridge) has been operated, and various observations with ESO facility spectrographs have been taken. The RPG radiometer has been validated across the range 0.5 - 9 mm demonstrating an accuracy of better than 0.1 mm. The saturation limit of the radiometer is about 20 mm. Currently, the radiometer is being integrated into the Paranal infrastructure to serve as a high time-resolution monitor in support of VLT science operations. The water vapour radiometer's ability to provide high precision, high time resolution information on this important aspect of the atmosphere will be most useful for conducting IR observations with the VLT under optimal conditions.

The impact of organic vapours on warm cloud formation; characterisation of chamber setup and first experimental results

NASA Astrophysics Data System (ADS)

Frey, Wiebke; Connolly, Paul; Dorsey, James; Hu, Dawei; Alfarra, Rami; McFiggans, Gordon

2016-04-01

The Manchester Ice Cloud Chamber (MICC), consisting of a 10m high stainless steel tube and 1m in diameter, can be used to study cloud processes. MICC is housed in three separate cold rooms stacked on top of each other and warm pseudo-adiabatic expansion from controlled initial temperature and pressure is possible through chamber evacuation. Further details about the facility can be found at http://www.cas.manchester.ac.uk/restools/cloudchamber/index.html. MICC can be connected to the Manchester Aerosol Chamber (MAC, http://www.cas.manchester.ac.uk/restools/aerosolchamber/), which allows to inject specified aerosol particles into the cloud chamber for nucleation studies. The combination of MAC and MICC will be used in the CCN-Vol project, which seeks to bring the experimental evidence for co-condensation of organic and water vapour in cloud formation which leads to an increase in cloud particle numbers (see Topping et al., 2013, Nature Geoscience Letters, for details). Here, we will show a characterisation of the cloud and aerosol chamber coupling in regard to background aerosol particles and nucleation. Furthermore, we will show preliminary results from the warm CCN-Vol experiment, investigating the impact of co-condensation of organic vapours and water vapour on warm cloud droplet formation.

Spectroscopic investigation of different concentrations of the vapour deposited copper phthalocyanine as a "guest" in polyimide matrix.

PubMed

Georgiev, Anton; Yordanov, Dancho; Dimov, Dean; Assa, Jacob; Spassova, Erinche; Danev, Gencho

2015-04-05

Nanocomposite layers 250 nm copper phthalocyanine/polyimide prepared by simultaneous vapour deposition of three different sources were studied. Different concentrations of copper phthalocyanine as a "guest" in polyimide matrix as a function of conditions of the preparation have been determined by FTIR (Fourier Transform Infrared) and UV-VIS (Ultraviolet-Visible) spectroscopies. The aim was to estimate the possibility of the spectroscopic methods for quantitative determination of the "guest" and compare with the quality of the polyimide thin films in relation to the "guest" concentration. The band at 1334 cm(-1) has been used for quantitative estimation of "guest" in polyimide matrix. The concentrations of the copper phthalocyanine less than 20% require curve fitting techniques with Fourier self deconvolution. The relationship between "guest" concentrations and degree of imidization, as well as the electronic UV-VIS spectra are discussed in relation to the composition, imidization degree and the two crystallographic modification of the embedded chromophore. Copyright © 2015 Elsevier B.V. All rights reserved.

Adsorption of water vapour and the specific surface area of arctic zone soils (Spitsbergen)

NASA Astrophysics Data System (ADS)

Cieśla, Jolanta; Sokołowska, Zofia; Witkowska-Walczak, Barbara; Skic, Kamil

2018-01-01

Water vapour/nitrogen adsorption were investigated and calculated the specific surface areas of arctic-zone soil samples (Turbic Cryosols) originating from different micro-relief forms (mud boils, cell forms and sorted circles) and from different depths. For the characterisation of the isotherms obtained for arctic soils, the Brunauer-Emmet-Teller model was then compared with the two other models (Aranovich-Donohue and Guggenheim-Anderson-de Boer) which were developed from Brunauer-Emmet-Teller. Specific surface area was calculated using the Brunauer-Emmet-Teller model at p p0-1 range of 0.05-0.35 for the water vapour desorption and nitrogen adsorption isotherms. The values of total specific surface area were the highest in Cryosols on mud boils, lower on cell forms, and the lowest on sorted circles. Such tendency was observed for the results obtained by both the water vapour and nitrogen adsorption. The differences in the values of specific surface area at two investigated layers were small. High determination coefficients were obtained for relationships between the specific surface areas and contents of clay and silt fraction in Cryosols. No statistically significant correlation between the total carbon amount and the values of specific surface area in Cryosols has been found.

The speed of sound in a gas–vapour bubbly liquid

PubMed Central

Prosperetti, Andrea

2015-01-01

In addition to the vapour of the liquid, bubbles in cavitating flows usually contain also a certain amount of permanent gas that diffuses out of the liquid as they grow. This paper presents a simplified linear model for the propagation of monochromatic pressure waves in a bubbly liquid with these characteristics. Phase change effects are included in detail, while the gas is assumed to follow a polytropic law. It is shown that even a small amount of permanent gas can have a major effect on the behaviour of the system. Particular attention is paid to the low-frequency range, which is of special concern in flow cavitation. Numerical results for water and liquid oxygen illustrate the implications of the model. PMID:26442146

The speed of sound in a gas-vapour bubbly liquid.

PubMed

Prosperetti, Andrea

2015-10-06

In addition to the vapour of the liquid, bubbles in cavitating flows usually contain also a certain amount of permanent gas that diffuses out of the liquid as they grow. This paper presents a simplified linear model for the propagation of monochromatic pressure waves in a bubbly liquid with these characteristics. Phase change effects are included in detail, while the gas is assumed to follow a polytropic law. It is shown that even a small amount of permanent gas can have a major effect on the behaviour of the system. Particular attention is paid to the low-frequency range, which is of special concern in flow cavitation. Numerical results for water and liquid oxygen illustrate the implications of the model.

A vapourized Δ(9)-tetrahydrocannabinol (Δ(9)-THC) delivery system part II: comparison of behavioural effects of pulmonary versus parenteral cannabinoid exposure in rodents.

PubMed

Manwell, Laurie A; Ford, Brittany; Matthews, Brittany A; Heipel, Heather; Mallet, Paul E

2014-01-01

Studies of the rewarding and addictive properties of cannabinoids using rodents as animal models of human behaviour often fail to replicate findings from human studies. Animal studies typically employ parenteral routes of administration, whereas humans typically smoke cannabis, thus discrepancies may be related to different pharmacokinetics of parenteral and pulmonary routes of administration. Accordingly, a novel delivery system of vapourized Δ(9)-tetrahydrocannabinol (Δ(9)-THC) was developed and assessed for its pharmacokinetic, pharmacodynamic, and behavioural effects in rodents. A commercially available vapourizer was used to assess the effects of pulmonary (vapourized) administration of Δ(9)-THC and directly compared to parenteral (intraperitoneal, IP) administration of Δ(9)-THC. Sprague-Dawley rats were exposed to pure Δ(9)-THC vapour (1, 2, 5, 10, and 20mg/pad), using a Volcano® vapourizing device (Storz and Bickel, Germany) or IP-administered Δ(9)-THC (0.1, 0.3, 0.5, 1.0mg/kg), and drug effects on locomotor activity, food and water consumption, and cross-sensitization to morphine (5mg/kg) were measured. Vapourized Δ(9)-THC significantly increased feeding during the first hour following exposure, whereas IP-administered Δ(9)-THC failed to produce a reliable increase in feeding at all doses tested. Acute administration of 10mg of vapourized Δ(9)-THC induced a short-lasting stimulation in locomotor activity compared to control in the first of four hours of testing over 7days of repeated exposure; this chronic exposure to 10mg of vapourized Δ(9)-THC did not induce behavioural sensitization to morphine. These results suggest vapourized Δ(9)-THC administration produces behavioural effects qualitatively different from those induced by IP administration in rodents. Furthermore, vapourized Δ(9)-THC delivery in rodents may produce behavioural effects more comparable to those observed in humans. We conclude that some of the conflicting findings in animal

The dynamic effects of metal vapour in gas metal arc welding

NASA Astrophysics Data System (ADS)

Haidar, Jawad

2010-04-01

Numerical simulations for the dynamic effects of metal vapour in gas metal arc welding (GMAW) suggest that vapour from the welding droplet at the tip of the welding wire has a significant influence on the plasma properties. It is found that for the evaporation rates calculated for arcs in pure argon, the dynamic effects of metal vapour markedly cool down the plasma in the central region of the arc, leading to the formation of a low temperature zone centred on the arc axis, in agreement with experimental measurements in the literature. Radiation effects, omitted in this paper, may produce further cooling of the plasma gas. The results highlight major deficiencies in the common approach to modelling the GMAW process and suggest that accurate description of GMAW must include the influence of metal vapour on the plasma.

The use of inverse gas chromatography and gravimetric vapour sorption to study transitions in amorphous lactose.

PubMed

Ambarkhane, Ameet V; Pincott, Kim; Buckton, Graham

2005-04-27

The aim of this study was to measure the glass transition of amorphous lactose under well-controlled temperature and humidity, using inverse gas chromatography (IGC) and to relate these data to gravimetric vapour sorption experiments. Amorphous lactose (spray-dried) was exposed to a stepwise increment in the relative humidity (%RH) under isothermal conditions in an IGC. At the end of each conditioning step a decane injection was made, and the retention volumes were calculated using the maximum peak height (V(max)) method. The pressure drop across the column was recorded using the pressure transducers. These measurements were performed at various temperatures from 25 to 40 degrees C. The extent of water sorption at identical humidity (%RH) and temperature conditions was determined gravimetrically using dynamic vapour sorption (DVS). At each T, it was possible to determine: (1) a transition at low RH relating to the onset of mobility; (2) changes in retention volume relating to the point, where T(g) = T; (3) changes in pressure drop, which were related to the sample collapse. The rate and extent of water sorption was seen to alter at T(g) and also at a collapse point. Combinations of temperature and critical %RH (%cRH required to lower the dry glass transition temperature to the experimental temperature) obtained from IGC were comparable to those obtained from DVS. It was shown that at each T, the sample spontaneously crystallised, when T(g) was 32 degrees C below T. Inverse gas chromatograph can be used in this novel way to reveal the series of transitions that occur in amorphous materials.

GPS tomographic experiment on water vapour dynamics in the troposphere over Lisbon

NASA Astrophysics Data System (ADS)

Benevides, Pedro; Catalao, Joao; Miranda, Pedro

2015-04-01

Quantification of the water vapour variability on the atmosphere remains a difficult task, affecting the weather prediction. Coarse water vapour resolution measurements in space and time affect the numerical weather prediction solution models causing artifacts in the prediction of severe weather phenomena. The GNSS atmospheric processing has been developed in the past years providing integrated water vapour estimates comparable with the meteorological sensor measurements, with studies registering 1 to 2 kg/m2 bias, but lack a vertical determination of the atmospheric processes. The GNSS tomography in the troposphere is one of the most promising techniques for sensing the three-dimensional water vapour state of the atmosphere. The determination of the integrated water vapour profile by means of the widely accepted GNSS meteorology techniques, allows the reconstruction of several slant path delay rays in the satellite line of view, providing an opportunity to sense the troposphere at tree-dimensions plus time. The tomographic system can estimate an image solution of the water vapour but impositions have to be introduced to the system of equations inversion because of the non-optimal GNSS observation geometry. Application of this technique on atmospheric processes like large convective precipitation or mesoscale water vapour circulation have been able to describe its local dynamic vertical variation. A 3D tomographic experiment was developed over an area of 60x60 km2 around Lisbon (Portugal). The GNSS network available composed by 9 receivers was used for an experiment of densification of the permanent network using 8 temporarily installed GPS receivers (totalling 17 stations). This study was performed during several weeks in July 2013, where a radiosonde campaign was also held in order to validate the tomographic inversion solution. 2D integrated water vapour maps directly obtained from the GNSS processing were also evaluated and local coastal breeze circulation

Measurements of the levels of organic solvent vapours by personal air samplers and the levels of urinary metabolites of workers. Part 2. Toluene vapour in a shipbuilding yard (author's transl).

PubMed

Kira, S

1977-05-01

Personal air samplers were applied to shipyard's painters putting on gas masks during the spraying work, and the levels of toluene vapour surrounding the workers were measured. On the other hand, levels of urinary hippuric acid (metabolites of toluene) of the workers were measured, and the levels of toluene vapour inhaled were calculated from the levels of urinary hippuric acid. Then the actual removing-efficiencies of toluene vapours by the use of gas masks were estimated from these two levels (i.e., toluene vapours exposed and inhaled). The values of removing-efficiencies were found to be 65.9-98.1%. The concentrations of hippuric and methylhippuric acids in the urine of workers exposed to toluene and xylene for 3 hours, collected just after the exposure, are valuable indices of these organic solvent vapours inhaled. A minute amount of urinary methylhippuric acid can be determined by means of gas chromatography.

Water vapour correction of the daily 1 km AVHRR global land dataset: Part I validation and use of the Water Vapour input field

USGS Publications Warehouse

DeFelice, Thomas P.; Lloyd, D.; Meyer, D.J.; Baltzer, T. T.; Piraina, P.

2003-01-01

An atmospheric correction algorithm developed for the 1 km Advanced Very High Resolution Radiometer (AVHRR) global land dataset was modified to include a near real-time total column water vapour data input field to account for the natural variability of atmospheric water vapour. The real-time data input field used for this study is the Television and Infrared Observational Satellite (TIROS) Operational Vertical Sounder (TOVS) Pathfinder A global total column water vapour dataset. It was validated prior to its use in the AVHRR atmospheric correction process using two North American AVHRR scenes, namely 13 June and 28 November 1996. The validation results are consistent with those reported by others and entail a comparison between TOVS, radiosonde, experimental sounding, microwave radiometer, and data from a hand-held sunphotometer. The use of this data layer as input to the AVHRR atmospheric correction process is discussed.

Spectroscopic interaction studies of substituted and unsubstituted copper phthalocyanine with adsorbed organic vapours

NASA Astrophysics Data System (ADS)

Ridhi, R.; Kang, Jasmeen; Saini, G. S. S.; Tripathi, S. K.

2018-05-01

The present study deals with comparing the interaction mechanism of adsorbed organic vapours with Copper Phthalocyanine thin films in its substituted and unsubstituted forms. For this purpose, the variations in vibrational levels of substituted CuPc (CuPcS) functionalized with tetrasulfonic acid tetrasodium salt and unsubstituted CuPc after exposure with methanol and benzene vapours is analyzed. Fourier transform infrared (FTIR) is used to study the interaction behaviour. The bulkier group tetrasulfonic acid tetrasodium salt added to CuPc leads to occupation of more space in the molecular arrangement as compared to unsubstituted CuPc and hence alteration of its properties. FTIR spectra of CuPc and CuPcS before and after vapours exposures highlighted the effect of these vapours on the various bonds and the role of functional group in altering the molecular structure of CuPcS during interaction with adsorbed vapours.

Influence of atmospheric vapour pressure deficit on ozone responses of snap bean (Phaseolus vulgaris L.) genotypes

PubMed Central

Fiscus, Edwin L.; Booker, Fitzgerald L.; Sadok, Walid; Burkey, Kent O.

2012-01-01

Environmental conditions influence plant responses to ozone (O3), but few studies have evaluated individual factors directly. In this study, the effect of O3 at high and low atmospheric vapour pressure deficit (VPD) was evaluated in two genotypes of snap bean (Phaseolus vulgaris L.) (R123 and S156) used as O3 bioindicator plants. Plants were grown in outdoor controlled-environment chambers in charcoal-filtered air containing 0 or 60 nl l−1 O3 (12 h average) at two VPDs (1.26 and 1.96 kPa) and sampled for biomass, leaf area, daily water loss, and seed yield. VPD clearly influenced O3 effects. At low VPD, O3 reduced biomass, leaf area, and seed yield substantially in both genotypes, while at high VPD, O3 had no significant effect on these components. In clean air, high VPD reduced biomass and yield by similar fractions in both genotypes compared with low VPD. Data suggest that a stomatal response to VPD per se may be lacking in both genotypes and it is hypothesized that the high VPD resulted in unsustainable transpiration and water deficits that resulted in reduced growth and yield. High VPD- and water-stress-induced stomatal responses may have reduced the O3 flux into the leaves, which contributed to a higher yield compared to the low VPD treatment in both genotypes. At low VPD, transpiration increased in the O3 treatment relative to the clean air treatment, suggesting that whole-plant conductance was increased by O3 exposure. Ozone-related biomass reductions at low VPD were proportionally higher in S156 than in R123, indicating that differential O3 sensitivity of these bioindicator plants remained evident when environmental conditions were conducive for O3 effects. Assessments of potential O3 impacts on vegetation should incorporate interacting factors such as VPD. PMID:22268148

Antifungal activity of clove essential oil and its volatile vapour against dermatophytic fungi.

PubMed

Chee, Hee Youn; Lee, Min Hee

2007-12-01

Antifungal activities of clove essential oil and its volatile vapour against dermatophytic fungi including Candida albicans, Epidermophyton floccosum. Microsporum audouinii, Trichophyton mentagrophytes, and Trichophyton rubrum were investigated. Both clove essential oil and its volatile vapour strongly inhibit spore germination and mycelial growth of the dermatophytic fungi tested. The volatile vapour of clove essential oil showed fungistatic activity whereas direct application of clove essential oil showed fungicidal activity.

Post-Contamination Vapour Hazards from Military Vehicles Contaminated with Thickened and Unthickened GD

DTIC Science & Technology

1979-02-01

The residual vapour hazards from four types of military vehicles previously contaminated with either thickened or unthickened GD have been measured...magnitude of these hazards have been investigated and an assessment made of their relevance to contamination control. It was found that on permeable... contamination had been applied were ineffective in reducing the subsequent vapour hazard; the vapour hazard arising from thickened GD contamination was less

The Seasonal Cycle of Water Vapour on Mars from Assimilation of Thermal Emission Spectrometer Data

NASA Technical Reports Server (NTRS)

Steele, Liam J.; Lewis, Stephen R.; Patel, Manish R.; Montmessin, Franck; Forget, Francois; Smith, Michael D.

2014-01-01

We present for the first time an assimilation of Thermal Emission Spectrometer (TES) water vapour column data into a Mars global climate model (MGCM). We discuss the seasonal cycle of water vapour, the processes responsible for the observed water vapour distribution, and the cross-hemispheric water transport. The assimilation scheme is shown to be robust in producing consistent reanalyses, and the global water vapour column error is reduced to around 2-4 pr micron depending on season. Wave activity is shown to play an important role in the water vapour distribution, with topographically steered flows around the Hellas and Argyre basins acting to increase transport in these regions in all seasons. At high northern latitudes, zonal wavenumber 1 and 2 stationary waves during northern summer are responsible for spreading the sublimed water vapour away from the pole. Transport by the zonal wavenumber 2 waves occurs primarily to the west of Tharsis and Arabia Terra and, combined with the effects of western boundary currents, this leads to peak water vapour column abundances here as observed by numerous spacecraft. A net transport of water to the northern hemisphere over the course of one Mars year is calculated, primarily because of the large northwards flux of water vapour which occurs during the local dust storm around L(sub S) = 240-260deg. Finally, outlying frost deposits that surround the north polar cap are shown to be important in creating the peak water vapour column abundances observed during northern summer.

Impact of major volcanic eruptions on stratospheric water vapour

NASA Astrophysics Data System (ADS)

Löffler, Michael; Brinkop, Sabine; Jöckel, Patrick

2016-05-01

Volcanic eruptions can have a significant impact on the Earth's weather and climate system. Besides the subsequent tropospheric changes, the stratosphere is also influenced by large eruptions. Here changes in stratospheric water vapour after the two major volcanic eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo on the Philippines in 1991 are investigated with chemistry-climate model simulations. This study is based on two simulations with specified dynamics of the European Centre for Medium-Range Weather Forecasts Hamburg - Modular Earth Submodel System (ECHAM/MESSy) Atmospheric Chemistry (EMAC) model, performed within the Earth System Chemistry integrated Modelling (ESCiMo) project, of which only one includes the long-wave volcanic forcing through prescribed aerosol optical properties. The results show a significant increase in stratospheric water vapour induced by the eruptions, resulting from increased heating rates and the subsequent changes in stratospheric and tropopause temperatures in the tropics. The tropical vertical advection and the South Asian summer monsoon are identified as sources for the additional water vapour in the stratosphere. Additionally, volcanic influences on tropospheric water vapour and El Niño-Southern Oscillation (ENSO) are evident, if the long-wave forcing is strong enough. Our results are corroborated by additional sensitivity simulations of the Mount Pinatubo period with reduced nudging and reduced volcanic aerosol extinction.

Evaluation of balloon and satellite water vapour measurements in the Southern tropical and subtropical UTLS during the HIBISCUS campaign

NASA Astrophysics Data System (ADS)

Montoux, N.; Hauchecorne, A.; Pommereau, J.-P.; Lefèvre, F.; Durry, G.; Jones, R. L.; Rozanov, A.; Dhomse, S.; Burrows, J. P.; Morel, B.; Bencherif, H.

2009-07-01

Balloon water vapour in situ and remote measurements in the tropical upper troposphere and lower stratosphere (UTLS) obtained during the HIBISCUS campaign around 20° S in Brazil in February-March 2004 using a tunable diode laser (μSDLA), a surface acoustic wave (SAW) and a Vis-NIR solar occultation spectrometer (SAOZ) on a long duration balloon, have been used for evaluating the performances of satellite borne remote water vapour instruments available at the same latitude and measurement period. In the stratosphere, HALOE displays the best precision (2.5%), followed by SAGE II (7%), MIPAS (10%), SAOZ (20-25%) and SCIAMACHY (35%), all of which show approximately constant H2O mixing ratios between 20-25 km. Compared to HALOE of ±10% accuracy between 0.1-100 hPa, SAGE II and SAOZ show insignificant biases, MIPAS is wetter by 10% and SCIAMACHY dryer by 20%. The currently available GOMOS profiles of 25% precision show a positive vertical gradient in error for identified reasons. Compared to these, the water vapour of the Reprobus Chemistry Transport Model, forced at pressures higher than 95 hPa by the ECMWF analyses, is dryer by about 1 ppmv (20%). In the lower stratosphere between 16-20 km, most notable features are the steep degradation of MIPAS precision below 18 km, and the appearance of biases between instruments far larger than their quoted total uncertainty. HALOE and SAGE II (after spectral adjustment for reducing the bias with HALOE at northern mid-latitudes) both show decreases of water vapour with a minimum at the tropopause not seen by other instruments or the model, possibly attributable to an increasing error in the HALOE altitude registration. Between 16-18 km where the water vapour concentration shows little horizontal variability, and where the μSDLA balloon measurements are not perturbed by outgassing, the average mixing ratios reported by the remote sensing instruments are substantially lower than the 4-5 ppmv observed by the μSDLA. Differences

Levels of selected carcinogens and toxicants in vapour from electronic cigarettes.

PubMed

Goniewicz, Maciej Lukasz; Knysak, Jakub; Gawron, Michal; Kosmider, Leon; Sobczak, Andrzej; Kurek, Jolanta; Prokopowicz, Adam; Jablonska-Czapla, Magdalena; Rosik-Dulewska, Czeslawa; Havel, Christopher; Jacob, Peyton; Benowitz, Neal

2014-03-01

Electronic cigarettes, also known as e-cigarettes, are devices designed to imitate regular cigarettes and deliver nicotine via inhalation without combusting tobacco. They are purported to deliver nicotine without other toxicants and to be a safer alternative to regular cigarettes. However, little toxicity testing has been performed to evaluate the chemical nature of vapour generated from e-cigarettes. The aim of this study was to screen e-cigarette vapours for content of four groups of potentially toxic and carcinogenic compounds: carbonyls, volatile organic compounds, nitrosamines and heavy metals. Vapours were generated from 12 brands of e-cigarettes and the reference product, the medicinal nicotine inhaler, in controlled conditions using a modified smoking machine. The selected toxic compounds were extracted from vapours into a solid or liquid phase and analysed with chromatographic and spectroscopy methods. We found that the e-cigarette vapours contained some toxic substances. The levels of the toxicants were 9-450 times lower than in cigarette smoke and were, in many cases, comparable with trace amounts found in the reference product. Our findings are consistent with the idea that substituting tobacco cigarettes with e-cigarettes may substantially reduce exposure to selected tobacco-specific toxicants. E-cigarettes as a harm reduction strategy among smokers unwilling to quit, warrants further study. (To view this abstract in Polish and German, please see the supplementary files online.).

Mixing of multiple metal vapours into an arc plasma in gas tungsten arc welding of stainless steel

NASA Astrophysics Data System (ADS)

Park, Hunkwan; Trautmann, Marcus; Tanaka, Keigo; Tanaka, Manabu; Murphy, Anthony B.

2017-11-01

A computational model of the mixing of multiple metal vapours, formed by vaporization of the surface of an alloy workpiece, into the thermal arc plasma in gas tungsten arc welding (GTAW) is presented. The model incorporates the combined diffusion coefficient method extended to allow treatment of three gases, and is applied to treat the transport of both chromium and iron vapour in the helium arc plasma. In contrast to previous models of GTAW, which predict that metal vapours are swept away to the edge of the arc by the plasma flow, it is found that the metal vapours penetrate strongly into the arc plasma, reaching the cathode region. The predicted results are consistent with published measurements of the intensity of atomic line radiation from the metal vapours. The concentration of chromium vapour is predicted to be higher than that of iron vapour due to its larger vaporization rate. An accumulation of chromium vapour is predicted to occur on the cathode at about 1.5 mm from the cathode tip, in agreement with published measurements. The arc temperature is predicted to be strongly reduced due to the strong radiative emission from the metal vapours. The driving forces causing the diffusion of metal vapours into the helium arc are examined, and it is found that diffusion due to the applied electric field (cataphoresis) is dominant. This is explained in terms of large ionization energies and the small mass of helium compared to those of the metal vapours.

Kinetic model of water vapour adsorption by gluten-free starch

NASA Astrophysics Data System (ADS)

Ocieczek, Aneta; Kostek, Robert; Ruszkowska, Millena

2015-01-01

This study evaluated the kinetics of water vapour adsorption on the surface of starch molecules derived from wheat. The aim of the study was to determine an equation that would allow estimation of water content in tested material in any timepoint of the adsorption process aimed at settling a balance with the environment. An adsorption isotherm of water vapour on starch granules was drawn. The parameters of the Guggenheim, Anderson, and De Boer equation were determined by characterizing the tested product and adsorption process. The equation of kinetics of water vapour adsorption on the surface of starch was determined based on the Guggenheim, Anderson, and De Boer model describing the state of equilibrium and on the model of a first-order linear inert element describing the changes in water content over time.

Evaluation of Pressure Generated by Resistors From Different Positive Expiratory Pressure Devices.

PubMed

Fagevik Olsén, Monika; Carlsson, Maria; Olsén, Erik; Westerdahl, Elisabeth

2015-10-01

Breathing exercises with positive expiratory pressure (PEP) are used to improve pulmonary function and airway clearance. Different PEP devices are available, but there have been no studies that describe the pressure generated by different resistors. The purpose of this study was to compare pressures generated from the proprietary resistor components of 4 commercial flow-dependent PEP valves with all other parameters kept constant. Resistors from 4 flow-regulated PEP devices (Pep/Rmt system, Wellspect HealthCare; Pipe P breathing exerciser, Koo Medical Equipment; Mini-PEP, Philips Respironics [including resistors by Rüsch]; and 15-mm endo-adapter, VBM Medizintechnik) were tested randomly by a blinded tester at constant flows of 10 and 18 L/min from an external gas system. All resistors were tested 3 times. Resistors with a similar diameter produced statistically significant different pressures at the same flow. The differences were smaller when the flow was 10 L/min compared with 18 L/min. The differences were also smaller when the diameter of the resistor was increased. The pressures produced by the 4 resistors of the same size were all significantly different when measuring 1.5- and 2.0-mm resistors at a flow of 10 L/min and 2.0-mm resistors at a flow of 18 L/min (P < .001). There were no significant differences between any of the resistors when testing sizes of 4.5 and 5.0 mm at either flow. The Mini-PEP and adapter resistors gave the highest pressures. Pressures generated by the different proprietary resistor components of 4 commercial PEP devices were not comparable, even though the diameter of the resistors is reported to be the same. The pressures generated were significantly different, particularly when using small-diameter resistors at a high flow. Therefore, the resistors may not be interchangeable. This is important information for clinicians, particularly when considering PEP for patients who do not tolerate higher pressures. Copyright © 2015 by

Plasma formation in water vapour layers in high conductivity liquids

NASA Astrophysics Data System (ADS)

Kelsey, C. P.; Schaper, L.; Stalder, K. R.; Graham, W. G.

2011-10-01

The vapour layer development stage of relatively low voltage plasmas in conducting solutions has already been well explored. The nature of the discharges formed within the vapour layer however is still largely unexplored. Here we examine the nature of such discharges through a combination of fast imaging and spatially, temporally resolved spectroscopy and electrical characterisation. The experimental setup used is a pin-to-plate discharge configuration with a -350V, 200 μs pulse applied at a repetition rate of 2Hz. A lens, followed by beam splitter allows beams to one Andor ICCD camera to capture images of the plasma emission with a second camera at the exit of a high resolution spectrometer. Through synchronization of the camera images at specified times after plasma ignition (as determined from current-voltage characteristics) they can be correlated with the spectra features. Initial measurements reveal two apparently different plasma formations. Stark broadening of the hydrogen Balmer beta line indicate electron densities of 3 to 5 ×1020 m-3 for plasmas produced early in the voltage pulse and an order of magnitude less for the later plasmas. The vapour layer development stage of relatively low voltage plasmas in conducting solutions has already been well explored. The nature of the discharges formed within the vapour layer however is still largely unexplored. Here we examine the nature of such discharges through a combination of fast imaging and spatially, temporally resolved spectroscopy and electrical characterisation. The experimental setup used is a pin-to-plate discharge configuration with a -350V, 200 μs pulse applied at a repetition rate of 2Hz. A lens, followed by beam splitter allows beams to one Andor ICCD camera to capture images of the plasma emission with a second camera at the exit of a high resolution spectrometer. Through synchronization of the camera images at specified times after plasma ignition (as determined from current

Water-vapour variability within a convective boundary-layer assessed by large-eddy simulations and IHOP_2002 observations

NASA Astrophysics Data System (ADS)

Couvreux, F.; Guichard, F.; Redelsperger, J. L.; Kiemle, C.; Masson, V.; Lafore, J. P.; Flamant, C.

2005-10-01

This study presents a comprehensive analysis of the variability of water vapour in a growing convective boundary-layer (CBL) over land, highlighting the complex links between advection, convective activity and moisture heterogeneity in the boundary layer. A Large-eddy Simulation (LES) is designed, based on observations, and validated, using an independent data-set collected during the International H2O Project (IHOP 2002) fieldexperiment. Ample information about the moisture distribution in space and time, as well as other important CBL parameters are acquired by mesonet stations, balloon soundings, instruments on-board two aircraft and the DLR airborne water-vapour differential-absorption lidar. Because it can deliver two-dimensional cross-sections at high spatial resolution (140 m horizontal, 200 m vertical), the airborne lidar offers valuable insights of small-scale moisture-variability throughout the CBL. The LES is able to reproduce the development of the CBL in the morning and early afternoon, as assessed by comparisons of simulated mean profiles of key meteorological variables with sounding data. Simulated profiles of the variance of water-vapour mixing-ratio were found to be in good agreement with the lidar-derived counterparts. Finally, probability-density functions of potential temperature, vertical velocity and water-vapour mixing-ratio calculated from the LES show great consistency with those derived from aircraft in situ measurements in the middle of the CBL. Downdraughts entrained from above the CBL are governing the scale of moisture variability. Characteristic length-scales are found to be larger for water-vapour mixing-ratio than for temperature.The observed water-vapour variability exhibits contributions from different scales. The influence of the mesoscale (larger than LES domain size, i.e. 10 km) on the smaller-scale variability is assessed using LES and observations. The small-scale variability of water vapour is found to be important and to be

Reliable determination of oxygen and hydrogen isotope ratios in atmospheric water vapour adsorbed on 3A molecular sieve.

PubMed

Han, Liang-Feng; Gröning, Manfred; Aggarwal, Pradeep; Helliker, Brent R

2006-01-01

The isotope ratio of atmospheric water vapour is determined by wide-ranging feedback effects from the isotope ratio of water in biological water pools, soil surface horizons, open water bodies and precipitation. Accurate determination of atmospheric water vapour isotope ratios is important for a broad range of research areas from leaf-scale to global-scale isotope studies. In spite of the importance of stable isotopic measurements of atmospheric water vapour, there is a paucity of published data available, largely because of the requirement for liquid nitrogen or dry ice for quantitative trapping of water vapour. We report results from a non-cryogenic method for quantitatively trapping atmospheric water vapour using 3A molecular sieve, although water is removed from the column using standard cryogenic methods. The molecular sieve column was conditioned with water of a known isotope ratio to 'set' the background signature of the molecular sieve. Two separate prototypes were developed, one for large collection volumes (3 mL) and one for small collection volumes (90 microL). Atmospheric water vapour was adsorbed to the column by pulling air through the column for several days to reach the desired final volume. Water was recovered from the column by baking at 250 degrees C in a dry helium or nitrogen air stream and cryogenically trapped. For the large-volume apparatus, the recovered water differed from water that was simultaneously trapped by liquid nitrogen (the experimental control) by 2.6 per thousand with a standard deviation (SD) of 1.5 per thousand for delta(2)H and by 0.3 per thousand with a SD of 0.2 per thousand for delta(18)O. Water-vapour recovery was not satisfactory for the small volume apparatus. Copyright (c) 2006 John Wiley & Sons, Ltd.

Water vapour and methane coupling in the stratosphere observed using SCIAMACHY solar occultation measurements

NASA Astrophysics Data System (ADS)

Noël, Stefan; Weigel, Katja; Bramstedt, Klaus; Rozanov, Alexei; Weber, Mark; Bovensmann, Heinrich; Burrows, John P.

2018-04-01

An improved stratospheric water vapour data set has been retrieved from SCIAMACHY/ENVISAT solar occultation measurements. It is similar to that successfully applied to methane and carbon dioxide. There is now a consistent set of data products for the three constituents covering the altitudes 17-45 km, the latitude range between about 50 and 70° N, and the period August 2002 to April 2012. The new water vapour concentration profiles agree with collocated results from ACE-FTS and MLS/Aura to within ˜ 5 %. A significant positive linear change in water vapour for the time 2003-2011 is observed at lower stratospheric altitudes with a value of about 0.015 ± 0.008 ppmv year-1 around 17 km. Between 30 and 37 km the changes become significantly negative (about -0.01 ± 0.008 ppmv year-1); all errors are 2σ values. The combined analysis of the SCIAMACHY methane and water vapour time series shows the expected anti-correlation between stratospheric methane and water vapour and a clear temporal variation related to the Quasi-Biennial Oscillation (QBO). Above about 20 km most of the additional water vapour is attributed to the oxidation of methane. In addition short-term fluctuations and longer-term variations on a timescale of 5-6 years are observed. The SCIAMACHY data confirm that at lower altitudes the amount of water vapour and methane are transported from the tropics to higher latitudes via the shallow branch of the Brewer-Dobson circulation.

Water vapour retrieval using the Precision Solar Spectroradiometer

NASA Astrophysics Data System (ADS)

Raptis, Panagiotis-Ioannis; Kazadzis, Stelios; Gröbner, Julian; Kouremeti, Natalia; Doppler, Lionel; Becker, Ralf; Helmis, Constantinos

2018-02-01

The Precision Solar Spectroradiometer (PSR) is a new spectroradiometer developed at Physikalisch-Meteorologisches Observatorium Davos - World Radiation Center (PMOD-WRC), Davos, measuring direct solar irradiance at the surface, in the 300-1020 nm spectral range and at high temporal resolution. The purpose of this work is to investigate the instrument's potential to retrieve integrated water vapour (IWV) using its spectral measurements. Two different approaches were developed in order to retrieve IWV: the first one uses single-channel and wavelength measurements, following a theoretical water vapour high absorption wavelength, and the second one uses direct sun irradiance integrated at a certain spectral region. IWV results have been validated using a 2-year data set, consisting of an AERONET sun-photometer Cimel CE318, a Global Positioning System (GPS), a microwave radiometer profiler (MWP) and radiosonde retrievals recorded at Meteorological Observatorium Lindenberg, Germany. For the monochromatic approach, better agreement with retrievals from other methods and instruments was achieved using the 946 nm channel, while for the spectral approach the 934-948 nm window was used. Compared to other instruments' retrievals, the monochromatic approach leads to mean relative differences up to 3.3 % with the coefficient of determination (R2) being in the region of 0.87-0.95, while for the spectral approach mean relative differences up to 0.7 % were recorded with R2 in the region of 0.96-0.98. Uncertainties related to IWV retrieval methods were investigated and found to be less than 0.28 cm for both methods. Absolute IWV deviations of differences between PSR and other instruments were determined the range of 0.08-0.30 cm and only in extreme cases would reach up to 15 %.

Applying a potential difference to minimise damage to carbon fibres during carbon nanotube grafting by chemical vapour deposition.

PubMed

Anthony, David B; Qian, Hui; Clancy, Adam J; Greenhalgh, Emile S; Bismarck, Alexander; Shaffer, Milo S P

2017-07-28

The application of an in situ potential difference between carbon fibres and a graphite foil counter electrode (300 V, generating an electric field ca 0.3-0.7 V μm -1 ), during the chemical vapour deposition synthesis of carbon nanotube (CNT) grafted carbon fibres, significantly improves the uniformity of growth without reducing the tensile properties of the underlying carbon fibres. Grafted CNTs with diameters 55 nm ± 36 nm and lengths around 10 μm were well attached to the carbon fibre surface, and were grown without the requirement for protective barrier coatings. The grafted CNTs increased the surface area to 185 m 2 g -1 compared to the as-received sized carbon fibre 0.24 m 2 g -1 . The approach is not restricted to batch systems and has the potential to improve CNT grafted carbon fibre production for continuous processing.

Applying a potential difference to minimise damage to carbon fibres during carbon nanotube grafting by chemical vapour deposition

NASA Astrophysics Data System (ADS)

Anthony, David B.; Qian, Hui; Clancy, Adam J.; Greenhalgh, Emile S.; Bismarck, Alexander; Shaffer, Milo S. P.

2017-07-01

The application of an in situ potential difference between carbon fibres and a graphite foil counter electrode (300 V, generating an electric field ca 0.3-0.7 V μm-1), during the chemical vapour deposition synthesis of carbon nanotube (CNT) grafted carbon fibres, significantly improves the uniformity of growth without reducing the tensile properties of the underlying carbon fibres. Grafted CNTs with diameters 55 nm ± 36 nm and lengths around 10 μm were well attached to the carbon fibre surface, and were grown without the requirement for protective barrier coatings. The grafted CNTs increased the surface area to 185 m2 g-1 compared to the as-received sized carbon fibre 0.24 m2 g-1. The approach is not restricted to batch systems and has the potential to improve CNT grafted carbon fibre production for continuous processing.

Airborne hygrometer calibration inter-comparison against a metrological water vapour standard

NASA Astrophysics Data System (ADS)

Smorgon, Denis; Boese, Norbert; Ebert, Volker

2014-05-01

of PTB and a validated, two-pressure generator acting as a highly stable and reproducible source of water vapour. The aim of AV2-B was to perform an absolute, metrological comparison of the field instruments/calibration infrastructures to the metrological humidity scale, and to collect essential information about methods and procedures used by the atmospheric community for instrument calibration and validation, in order to investigate e.g. the necessity and possible comparability advantage by a standardized calibration procedure. The work will give an overview over the concept of the AV2-B inter-comparison, the various general measurement and calibration principles, and discuss the outcome and consequences of the comparison effort. The AQUAVIT effort is linked to the EMRP project METEOMET (ENV07) and partially supported by the EMRP and ENV07. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union. [1] H. Saathoff, C. Schiller, V. Ebert, D. W. Fahey, R.-S. Gao, O. Möhler, and the aquavit team, The AQUAVIT formal intercomparison of atmospheric water measurement methods, 5th General Assembly of the European Geosciences Union, 13-18 April 2008, Vienna, Austria Keywords: humidity, water vapour, inter-comparison, airborne instruments.

Experimental and Theoretical Studies of Condensation on a Horizontal Tube Row with Vapour Shear

NASA Astrophysics Data System (ADS)

Aoune, Azzeddine

Available from UMI in association with The British Library. This thesis presents an experimental and theoretical investigation into the effect of vapour shear on the condensation of steam flowing vertically downwards over a single horizontal tube and a horizontal tube in a row. Honda and Fujii's conjugate heat transfer analysis has been adapted and modified to take account of property variation with temperature and release of sensible heat to the condensing film. In industrial condensers, even in the first row, the vapour velocity profile around a tube is affected by the presence of its neighbours. This work extends Honda and Fujii's analysis to investigate the effect of tube spacing on the heat transfer. The finite element method was used to obtain the velocity field around the tube in a row and subsequently the boundary layer equations for the condensate and vapour film along with the heat flow in the tube wall were solved simultaneously. Data have been obtained at absolute pressures of 0.8 and 0.9 bar and for steam superheat up to 40 degC. Approach steam velocities up to 25 m/s were covered. Cooling water velocities and temperatures were in the range 0.68-1.16 m/s and 18-43^circ C, respectively. Honda et al (67), Roshko's flow, theory was found to fit the data for the steam flowing over the isolated tube. The theoretical data for the latter agreed well with the Shekriladze and Gomelauri (2) and Rose (40) correlations and Honda et al (67), potential flow, theory. On | Nu| Re^{-1/2} versus F basis, an average enhancement of 50% in condensate film heat transfer was observed in the case of steam flowing over the tube in a row compared to the isolated tube. This compared with the predicted value of 23% enhancement.

Aerosol assisted chemical vapour deposition of gas sensitive SnO2 and Au-functionalised SnO2 nanorods via a non-catalysed vapour solid (VS) mechanism

PubMed Central

Vallejos, Stella; Selina, Soultana; Annanouch, Fatima Ezahra; Gràcia, Isabel; Llobet, Eduard; Blackman, Chris

2016-01-01

Tin oxide nanorods (NRs) are vapour synthesised at relatively lower temperatures than previously reported and without the need for substrate pre-treatment, via a vapour-solid mechanism enabled using an aerosol-assisted chemical vapour deposition method. Results demonstrate that the growth of SnO2 NRs is promoted by a compression of the nucleation rate parallel to the substrate and a decrease of the energy barrier for growth perpendicular to the substrate, which are controlled via the deposition conditions. This method provides both single-step formation of the SnO2 NRs and their integration with silicon micromachined platforms, but also allows for in-situ functionalization of the NRs with gold nanoparticles via co-deposition with a gold precursor. The functional properties are demonstrated for gas sensing, with microsensors using functionalised NRs demonstrating enhanced sensing properties towards H2 compared to those based on non-functionalised NRs. PMID:27334232

Pan-derived isotopic composition of atmospheric vapour in a Mediterranean wetland (Rhône River Delta, France).

PubMed

Vallet-Coulomb, Christine; Cartapanis, Olivier; Radakovitch, Olivier; Sonzogni, Corinne; Pichaud, Marc

2010-03-01

A continuous record of atmospheric vapour isotopic composition (delta(A)) can be derived from the isotope mass balance of a water body submitted to natural evaporation. In this paper, we present preliminary results of the application of this method to a drying evaporation pan, located in a Mediterranean wetland, during a two-month summer period. Results seem consistent with few atmospheric vapour data based on the assumption of isotopic equilibrium with precipitation, but we observed a shift between pan-derived delta(A) and the composition of vapour samples collected by cold trapping. These results suggest that further investigations are necessary to evaluate the effect of diurnal variations of atmospheric conditions on the applicability of the pan-evaporation method, and on the representative of grab atmospheric samples. We also propose a sensitivity analysis for evaluating the impact of the different measured components on delta(A) calculation, and show an improvement in the method efficiency as the pan is drying.

Exposure to oil mist and oil vapour during offshore drilling in norway, 1979-2004.

PubMed

Steinsvåg, Kjersti; Bråtveit, Magne; Moen, Bente E

2006-03-01

To describe personal exposure to airborne hydrocarbon contaminants (oil mist and oil vapour) from 1979 to 2004 in the mud-handling areas of offshore drilling facilities operating on the Norwegian continental shelf when drilling with oil-based muds. Qualitative and quantitative information was gathered during visits to companies involved in offshore oil and gas production in Norway. Monitoring reports on oil mist and oil vapour exposure covered 37 drilling facilities. Exposure data were analysed using descriptive statistics and by constructing linear mixed-effects models. Samples had been taken during the use of three generations of hydrocarbon base oils, namely diesel oils (1979-1984), low-aromatic mineral oils (1985-1997) and non-aromatic mineral oils (1998-2004). Sampling done before 1984 showed high exposure to diesel vapour (arithmetic mean, AM = 1217 mg m(-3)). When low-aromatic mineral oils were used, the exposure to oil mist and oil vapour was 4.3 and 36 mg m(-3), and the respective AMs for non-aromatic mineral oils were reduced to 0.54 and 16 mg m(-3). Downward time trends were indicated for both oil mist (6% per year) and oil vapour (8% per year) when the year of monitoring was introduced as a fixed effect in a linear mixed-effects model analysis. Rig type, technical control measures and mud temperature significantly determined exposure to oil mist. Rig type, type of base oil, viscosity of the base oil, work area, mud temperature and season significantly determined exposure to oil vapour. Major decreases in variability were found for the between-rig components. Exposure to oil mist and oil vapour declined over time in the mud-handling areas of offshore drilling facilities. Exposure levels were associated with rig type, mud temperature, technical control measures, base oil, viscosity of the base oil, work area and season.

In-vitro and in-vivo anti-Trichophyton activity of essential oils by vapour contact.

PubMed

Inouye, S; Uchida, K; Yamaguchi, H

2001-05-01

The minimum inhibitory doses (MIDs) of essential oils by vapour contact to inhibit the growth of Trichophyton mentagrophytes and Trichophyton rubrum on agar medium were determined using airtight boxes. Among seven essential oils examined, cinnamon bark oil showed the least MID, followed by lemongrass, thyme and perilla oils. Lavender and tea tree oils showed moderate MID, and citron oil showed the highest MID, being 320 times higher than that of cinnamon bark oil. The MID values were less than the minimum inhibitory concentration (MIC) values determined by agar dilution assay. Furthermore, the minimum agar concentration (MAC) of essential oils absorbed from vapour was determined at the time of MID determination as the second antifungal measure. The MAC value by vapour contact was 1.4 to 4.7 times less than the MAC remaining in the agar at the time of MIC determination by agar dilution assay. Using selected essential oils, the anti-Trichophyton activity by vapour contact was examined in more detail. Lemongrass, thyme and perilla oils killed the conidia, inhibited germination and hyphal elongation at 1-4 micrograms ml-1 air, whereas lavender oil was effective at 40-160 micrograms ml-1 air. The in-vivo efficacy of thyme and perilla oils by vapour contact was shown against an experimental tinea pedis in guinea pigs infected with T. mentagrophytes. These results indicated potent anti-Trichophyton action of essential oils by vapour contact.

GPS water vapour tomography: preliminary results from the ESCOMPTE field experiment

NASA Astrophysics Data System (ADS)

Champollion, C.; Masson, F.; Bouin, M.-N.; Walpersdorf, A.; Doerflinger, E.; Bock, O.; Van Baelen, J.

2005-03-01

Water vapour plays a major role in atmospheric processes but remains difficult to quantify due to its high variability in time and space and the sparse set of available measurements. The GPS has proved its capacity to measure the integrated water vapour at zenith with the same accuracy as other methods. Recent studies show that it is possible to quantify the integrated water vapour in the line of sight of the GPS satellite. These observations can be used to study the 3D heterogeneity of the troposphere using tomographic techniques. We develop three-dimensional tomographic software to model the three-dimensional distribution of the tropospheric water vapour from GPS data. First, the tomographic software is validated by simulations based on the realistic ESCOMPTE GPS network configuration. Without a priori information, the absolute value of water vapour is less resolved as opposed to relative horizontal variations. During the ESCOMPTE field experiment, a dense network of 17 dual frequency GPS receivers was operated for 2 weeks within a 20×20-km area around Marseille (southern France). The network extends from sea level to the top of the Etoile chain (˜700 m high). Optimal results have been obtained with time windows of 30-min intervals and input data evaluation every 15 min. The optimal grid for the ESCOMTE geometrical configuration has a horizontal step size of 0.05°×0.05° and 500 m vertical step size. Second, we have compared the results of real data inversions with independent observations. Three inversions have been compared to three successive radiosonde launches and shown to be consistent. A good resolution compared to the a priori information is obtained up to heights of 3000 m. A humidity spike at 4000-m altitude remains unresolved. The reason is probably that the signal is spread homogeneously over the whole network and that such a feature is not resolvable by tomographic techniques. The results of our pure GPS inversion show a correlation with

The vapour of imidazolium-based ionic liquids: a mass spectrometry study.

PubMed

Deyko, A; Lovelock, K R J; Licence, P; Jones, R G

2011-10-06

Eight common dialkylimidazolium-based ionic liquids have been successfully evaporated in ultra-high vacuum and their vapours analysed by line of sight mass spectrometry using electron ionisation. The ionic liquids investigated were 1-alkyl-3-methylimidazolium bis[(trifluoromethane)sulfonyl]imide, [C(n)C(1)Im][Tf(2)N] (where n = 2, 4, 6, 8), 1-alkyl-3-methylimidazolium tetrafluoroborate, [C(n)C(1)Im][BF(4)] (where n = 4, 8), 1-butyl-3-methylimidazolium octylsulfate, [C(4)C(1)Im][C(8)OSO(3)] and 1-butyl-3-methylimidazolium tetrachloroferrate, [C(4)C(1)Im][FeCl(4)]. All ionic liquids studied here evaporated as neutral ion pairs; no evidence of decomposition products in the vapour phase were observed. Key fragment cations of the ionised vapour of the ionic liquids are identified. The appearance energies, E(app), of the parent cation were measured and used to estimate the ionisation energies, E(i), for the vapour phase neutral ion pairs. Measured ionisation energies ranged from 10.5 eV to 13.0 eV. Using both the identity and E(app) values, the fragmentation pathways for a number of fragment cations are postulated. It will be shown that the enthalpy of vaporisation, Δ(vap)H, can successfully be measured using more than one fragment cation, although caution is required as many fragment cations can also be formed by ionisation of decomposition products.

Nicotine content of electronic cigarettes, its release in vapour and its consistency across batches: regulatory implications.

PubMed

Goniewicz, Maciej L; Hajek, Peter; McRobbie, Hayden

2014-03-01

Electronic cigarettes (EC) may have a potential for public health benefit as a safer alternative to smoking, but questions have been raised about whether EC should be licensed as a medicine, with accurate labelling of nicotine content. This study determined the nicotine content of the cartridges of the most popular EC brands in the United Kingdom and the nicotine levels they deliver in the vapour, and estimated the safety and consistency of nicotine delivery across batches of the same product as a proxy for quality control for individual brands and within the industry. We studied five UK brands (six products) with high internet popularity. Two samples of each brand were purchased 4 weeks apart, and analysed for nicotine content in the cartridges and nicotine delivery in vapour. The nicotine content of cartridges within the same batch varied by up to 12% relative standard deviation (RSD) and the mean difference between different batches of the same brand ranged from 1% [95% confidence interval (CI) = -5 to 7%] to 20% (95% CI=14-25%) for five brands and 31% (95% CI=21-39%) for the sixth. The puffing schedule used in this study vaporized 10-81% of the nicotine present in the cartridges. The nicotine delivery from 300 puffs ranged from ∼2 mg to ∼15 mg and was not related significantly to the variation of nicotine content in e-liquid (r=0.06, P=0.92). None of the tested products allowed access to e-liquid or produced vapour nicotine concentrations as high as conventional cigarettes. There is very little risk of nicotine toxicity from major electronic cigarette (EC) brands in the United Kingdom. Variation in nicotine concentration in the vapour from a given brand is low. Nicotine concentration in e-liquid is not well related to nicotine in vapour. Other EC brands may be of lower quality and consumer protection regulation needs to be implemented, but in terms of accuracy of labelling of nicotine content and risks of nicotine overdose, regulation over and above

Delaying microbial proliferation in freshly peeled shallots by active packaging incorporating ethanol vapour-controlled release sachets and low storage temperature.

PubMed

Utto, Weerawate; Preutikul, Rittirong; Malila, Patcharee; Noomhorm, Athapol; Bronlund, John E

2018-03-01

This research was conducted to investigate effects of ethanol vapour released in active packaging and storage temperatures on the quality of freshly peeled shallots. The package tested was a solid polypropylene tray incorporating an ethanol vapour-controlled release sachet. The sachet was made of an aluminium foil film on one side and either low-density polyethylene or nylon/polyethylene on the other. Individual sachets contained silica gel adsorbent as the carrier pre-loaded with ethanol. One sachet was placed in each tray containing the peeled shallots and the tray was heat sealed with the low-density polyethylene film lid. Packages were stored at either 10 or 25 ℃ for 10 d. Trays containing only peeled shallots were designated as controls. High storage temperature stimulated quality changes in the shallots. Although ethanol vapour accumulated in the active package headspace, the extent to which ethanol concentrations increased within the shallots was not significantly different from that in the control packages. Microbial proliferation in terms of yeast and mould counts could be delayed through a combination of 10 ℃ and ethanol vapour released from the low-density polyethylene sachet. The ethanol vapour accumulated in the packages did not have a significant effect on mass loss, firmness, and colour changes in the peeled shallots, or on the concentrations of oxygen and carbon dioxide in the packages.

Clearing the air: protocol for a systematic meta-narrative review on the harms and benefits of e-cigarettes and vapour devices.

PubMed

MacDonald, Marjorie; O'Leary, Renee; Stockwell, Tim; Reist, Dan

2016-05-21

Under the shadow of the tobacco epidemic, the sale and use of e-cigarettes and other vapour devices is increasing dramatically. A contentious debate has risen within public health over the harms and benefits of these devices. Clearing the Air seeks to clarify the issues with a systematic review that informs the pressing regulatory and public health decisions to be made regarding these new products. Using an integrated knowledge translation approach, public health researchers and knowledge users will work collaboratively throughout the project. Our research questions are the following: (1) What are the health risks and benefits of vapour devices, and how do these compare to cigarettes? (2) What is the harm reduction potential of vapour devices for individuals, the environment, and society? (3) Does youth vapour device experimentation lead to cigarette use? (4) Can vapour devices be effective aids for tobacco cessation? and (5) What is the potential toxicity of second-hand vapour? We are using meta-narrative review to synthesize studies from diverse research traditions because of its capacity to address contestations around a topic. The project has six phases. In the planning phase, we finalized the research questions. In the search phase, we are locating academic publications and grey literature aided by a research librarian. The mapping phase involves categorizing these papers into research traditions to understand different perspectives on the evidence for each research question. In the appraisal phase, we will select and evaluate the relevant papers. Finally, in the synthesis phase, using analytic techniques unique to meta-narrative methodology, we will compare and contrast the evidence from different research traditions to answer our research questions, identifying overarching meta-narratives. In the final stage, the full team will draft recommendations to be disseminated through a variety of knowledge translation strategies. Meta-narrative synthesis has the

A dilute Cu(Ni) alloy for synthesis of large-area Bernal stacked bilayer graphene using atmospheric pressure chemical vapour deposition

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

Madito, M. J.; Bello, A.; Dangbegnon, J. K.

2016-01-07

A bilayer graphene film obtained on copper (Cu) foil is known to have a significant fraction of non-Bernal (AB) stacking and on copper/nickel (Cu/Ni) thin films is known to grow over a large-area with AB stacking. In this study, annealed Cu foils for graphene growth were doped with small concentrations of Ni to obtain dilute Cu(Ni) alloys in which the hydrocarbon decomposition rate of Cu will be enhanced by Ni during synthesis of large-area AB-stacked bilayer graphene using atmospheric pressure chemical vapour deposition. The Ni doped concentration and the Ni homogeneous distribution in Cu foil were confirmed with inductively coupledmore » plasma optical emission spectrometry and proton-induced X-ray emission. An electron backscatter diffraction map showed that Cu foils have a single (001) surface orientation which leads to a uniform growth rate on Cu surface in early stages of graphene growth and also leads to a uniform Ni surface concentration distribution through segregation kinetics. The increase in Ni surface concentration in foils was investigated with time-of-flight secondary ion mass spectrometry. The quality of graphene, the number of graphene layers, and the layers stacking order in synthesized bilayer graphene films were confirmed by Raman and electron diffraction measurements. A four point probe station was used to measure the sheet resistance of graphene films. As compared to Cu foil, the prepared dilute Cu(Ni) alloy demonstrated the good capability of growing large-area AB-stacked bilayer graphene film by increasing Ni content in Cu surface layer.« less

A dilute Cu(Ni) alloy for synthesis of large-area Bernal stacked bilayer graphene using atmospheric pressure chemical vapour deposition

NASA Astrophysics Data System (ADS)

Madito, M. J.; Bello, A.; Dangbegnon, J. K.; Oliphant, C. J.; Jordaan, W. A.; Momodu, D. Y.; Masikhwa, T. M.; Barzegar, F.; Fabiane, M.; Manyala, N.

2016-01-01

A bilayer graphene film obtained on copper (Cu) foil is known to have a significant fraction of non-Bernal (AB) stacking and on copper/nickel (Cu/Ni) thin films is known to grow over a large-area with AB stacking. In this study, annealed Cu foils for graphene growth were doped with small concentrations of Ni to obtain dilute Cu(Ni) alloys in which the hydrocarbon decomposition rate of Cu will be enhanced by Ni during synthesis of large-area AB-stacked bilayer graphene using atmospheric pressure chemical vapour deposition. The Ni doped concentration and the Ni homogeneous distribution in Cu foil were confirmed with inductively coupled plasma optical emission spectrometry and proton-induced X-ray emission. An electron backscatter diffraction map showed that Cu foils have a single (001) surface orientation which leads to a uniform growth rate on Cu surface in early stages of graphene growth and also leads to a uniform Ni surface concentration distribution through segregation kinetics. The increase in Ni surface concentration in foils was investigated with time-of-flight secondary ion mass spectrometry. The quality of graphene, the number of graphene layers, and the layers stacking order in synthesized bilayer graphene films were confirmed by Raman and electron diffraction measurements. A four point probe station was used to measure the sheet resistance of graphene films. As compared to Cu foil, the prepared dilute Cu(Ni) alloy demonstrated the good capability of growing large-area AB-stacked bilayer graphene film by increasing Ni content in Cu surface layer.

Influence of metallic vapours on thermodynamic and transport properties of two-temperature air plasma

NASA Astrophysics Data System (ADS)

Zhong, Linlin; Wang, Xiaohua; Cressault, Yann; Teulet, Philippe; Rong, Mingzhe

2016-09-01

The metallic vapours (i.e., copper, iron, and silver in this paper) resulting from walls and/or electrode surfaces can significantly affect the characteristics of air plasma. Different from the previous works assuming local thermodynamic equilibrium, this paper investigates the influence of metallic vapours on two-temperature (2 T) air plasma. The 2 T compositions of air contaminated by Cu, Fe, and Ag are first determined based on Saha's and Guldberg-Waage's laws. The thermodynamic properties (including mass density, specific enthalpy, and specific heat) are then calculated according to their definitions. After determining the collision integrals for each pair of species in air-metal mixtures using the newly published methods and source data, the transport coefficients (including electrical conductivity, viscosity, and thermal conductivity) are calculated for air-Cu, air-Fe, and air-Ag plasmas with different non-equilibrium degree θ (Te/Th). The influences of metallic contamination as well as non-equilibrium degree are discussed. It is found that copper, iron, and silver exist mainly in the form of Cu2, FeO, and AgO at low temperatures. Generally, the metallic vapours increase mass density at most temperatures, reduce the specific enthalpy and specific heat in the whole temperature range, and affect the transport properties remarkably from 5000 K to 20 000 K. The effect arising from the type of metals is little except for silver at certain temperatures. Besides, the departure from thermal equilibrium results in the delay of dissociation and ionization reactions, leading to the shift of thermodynamic and transport properties towards a higher temperature.

Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour.

PubMed

Martin, T L; Coe, C; Bagot, P A J; Morrall, P; Smith, G D W; Scott, T; Moody, M P

2016-07-12

Understanding the corrosion of uranium is important for its safe, long-term storage. Uranium metal corrodes rapidly in air, but the exact mechanism remains subject to debate. Atom Probe Tomography was used to investigate the surface microstructure of metallic depleted uranium specimens following polishing and exposure to moist air. A complex, corrugated metal-oxide interface was observed, with approximately 60 at.% oxygen content within the oxide. Interestingly, a very thin (~5 nm) interfacial layer of uranium hydride was observed at the oxide-metal interface. Exposure to deuterated water vapour produced an equivalent deuteride signal at the metal-oxide interface, confirming the hydride as originating via the water vapour oxidation mechanism. Hydroxide ions were detected uniformly throughout the oxide, yet showed reduced prominence at the metal interface. These results support a proposed mechanism for the oxidation of uranium in water vapour environments where the transport of hydroxyl species and the formation of hydride are key to understanding the observed behaviour.

Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour

NASA Astrophysics Data System (ADS)

Martin, T. L.; Coe, C.; Bagot, P. A. J.; Morrall, P.; Smith, G. D. W.; Scott, T.; Moody, M. P.

2016-07-01

Understanding the corrosion of uranium is important for its safe, long-term storage. Uranium metal corrodes rapidly in air, but the exact mechanism remains subject to debate. Atom Probe Tomography was used to investigate the surface microstructure of metallic depleted uranium specimens following polishing and exposure to moist air. A complex, corrugated metal-oxide interface was observed, with approximately 60 at.% oxygen content within the oxide. Interestingly, a very thin (~5 nm) interfacial layer of uranium hydride was observed at the oxide-metal interface. Exposure to deuterated water vapour produced an equivalent deuteride signal at the metal-oxide interface, confirming the hydride as originating via the water vapour oxidation mechanism. Hydroxide ions were detected uniformly throughout the oxide, yet showed reduced prominence at the metal interface. These results support a proposed mechanism for the oxidation of uranium in water vapour environments where the transport of hydroxyl species and the formation of hydride are key to understanding the observed behaviour.

Preliminary Martian Atmospheric Water Vapour Column Abundances with Mars Climate Sounder

NASA Astrophysics Data System (ADS)

Lolachi, Ramin; Irwin, P. G. J.; Teanby, N.; Calcutt, S.; Howett, C. J. A.; Bowles, N. E.; Taylor, F. W.; Schofield, J. T.; Kleinboehl, A.; McCleese, D. J.

2007-12-01

Mars Climate Sounder (MCS) is an infra-red radiometer on board NASA's Mars Reconnaissance Orbiter (MRO) launched in August 2005 and now orbiting Mars in a near circular polar orbit. MCS has nine spectral channels in the range 0.3-50 µm. Goals of MCS include global characterization of atmospheric temperature, dust and water profiles observing temporal and spatial variation. Using Oxford University's multivariate retrieval algorithm, NEMESIS, we present preliminary determinations of the water vapour column abundance in the Martian atmosphere during the period September-October 2006 (Ls range 111-129°, i.e. northern hemisphere summer). A combination of spectral channels inside and outside the water vapour rotation band (at 50 µm) are used to retrieve the column abundances mainly using nadir observations (as aerosol opacity is less important relative to water vapour opacity in nadir viewing geometry). We then compare these column abundances to earlier results from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) and the Thermal Emission Spectrometer (TES) on Mars Global Surveyor.

Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour

PubMed Central

Martin, T. L.; Coe, C.; Bagot, P. A. J.; Morrall, P.; Smith, G. D. W; Scott, T.; Moody, M. P.

2016-01-01

Understanding the corrosion of uranium is important for its safe, long-term storage. Uranium metal corrodes rapidly in air, but the exact mechanism remains subject to debate. Atom Probe Tomography was used to investigate the surface microstructure of metallic depleted uranium specimens following polishing and exposure to moist air. A complex, corrugated metal-oxide interface was observed, with approximately 60 at.% oxygen content within the oxide. Interestingly, a very thin (~5 nm) interfacial layer of uranium hydride was observed at the oxide-metal interface. Exposure to deuterated water vapour produced an equivalent deuteride signal at the metal-oxide interface, confirming the hydride as originating via the water vapour oxidation mechanism. Hydroxide ions were detected uniformly throughout the oxide, yet showed reduced prominence at the metal interface. These results support a proposed mechanism for the oxidation of uranium in water vapour environments where the transport of hydroxyl species and the formation of hydride are key to understanding the observed behaviour. PMID:27403638

MEDUSA: The ExoMars experiment for in-situ monitoring of dust and water vapour

NASA Astrophysics Data System (ADS)

Colangeli, L.; Lopez-Moreno, J. J.; Nørnberg, P.; Della Corte, V.; Esposito, F.; Mazzotta Epifani, E.; Merrison, J.; Molfese, C.; Palumbo, P.; Rodriguez-Gomez, J. F.; Rotundi, A.; Visconti, G.; Zarnecki, J. C.; The International Medusa Team

2009-07-01

Dust and water vapour are fundamental components of the Martian atmosphere. In view of tracing the past environmental conditions on Mars, that possibly favoured the appearing of life forms, it is important to study the present climate and its evolution. Here dust and water vapour have (and have had) strong influence. Of major scientific interest is the quantity and physical, chemical and electrical properties of dust and the abundance of water vapour dispersed in the atmosphere and their exchange with the surface. Moreover, in view of the exploration of the planet with automated systems and in the future by manned missions, it is of primary importance to analyse the hazards linked to these environmental factors. The Martian Environmental Dust Systematic Analyser (MEDUSA) experiment, included in the scientific payload of the ESA ExoMars mission, accommodates a complement of sensors, based on optical detection and cumulative mass deposition, that aims to study dust and water vapour in the lower Martian atmosphere. The goals are to study, for the first time, in-situ and quantitatively, physical properties of the airborne dust, including the cumulative dust mass flux, the dust deposition rate, the physical and electrification properties, the size distribution of sampled particles and the atmospheric water vapour abundance versus time.

Effects of nitrogen and vapour pressure deficit on phytomer growth and development in a C4 grass.

PubMed

Yang, Fang; Gong, Xiao Ying; Liu, Hai Tao; Schäufele, Rudi; Schnyder, Hans

2016-01-01

Phytomers are basic morphological units of plants. Knowledge of phytomer development is essential for understanding morphological plasticity, functional-structural modelling of plant growth and the usage of leaf characteristics to indicate growth conditions at the time of production (e.g. stable isotope signals). Yet, systematic analysis on the process of phytomer development is unavailable for wild or perennial C 4 grasses. Also, effects of environmental factors, such as nitrogen nutrition or vapour pressure deficit (VPD), on coordination events of developmental processes of C 4 grasses have not been studied. This study investigates phytomer growth and development in Cleistogenes squarrosa, a predominant C 4 grass in the Eurasian steppe, grown at low (0.63 kPa) or high (1.58 kPa) VPD with low or high nitrogen supply in controlled environments. Elongation of phytomers on marked tillers was measured daily for 13 days. Then lengths of immature and mature phytomer components (blade, sheath and internode) of all phytomers were measured following dissection. Nitrogen nutrition and VPD had no effects on coordination of growth within and between phytomers: phytomer tips emerged when phytomers reached 26 % of their final length, coincident with the acceleration phase of its elongation; blade elongation stopped when phytomers reached ∼75 % of their final length and elongation of the preceding phytomer was confined to the internode. The relationship between fraction of final phytomer length and days after tip emergence for all treatments was well described by a sigmoidal function: y = 1/{1 + exp[(1.82 - x)/1.81]}. C. squarrosa exhibited little morphological plasticity at phytomer-level in response to nitrogen supply and VPD, but a clear increase in tillering under high N supply. Also, the invariant coordination of elongation within and between phytomers was a stable developmental feature, thus the quantitative coordination rules are applicable for

Fabrication of zinc-dicarboxylate- and zinc-pyrazolate-carboxylate-framework thin films through vapour-solid deposition.

PubMed

Medishetty, Raghavender; Zhang, Zongji; Sadlo, Alexander; Cwik, Stefan; Peeters, Daniel; Henke, Sebastian; Mangayarkarasi, Nagarathinam; Devi, Anjana

2018-05-17

Fabrication of three-dimensional metal-organic framework (MOF) thin films has been investigated for the first time through the conversion of a ZnO layer via a pure vapour-solid deposition reaction at ambient pressure. The fabrication of MOF thin films with a dicarboxylate linker, (DMA)2[Zn3(bdc)4] (1) (bdc = 1,4-benzenedicarboxylate), and a carboxy-pyrazolate linker, [Zn4O(dmcapz)6] (2) (dmcapz = 3,5-dimethyl-4-carboxypyrazole), involves the deposition of the linker and/or the preparation of a composite film preliminarily and its subsequent conversion into a MOF film using closed cell thermal treatment. Furthermore, it was possible to isolate thin films with a MOF-5 isotype structure grown along the [110] direction, using a carboxy-pyrazolate linker. This was achieved just by the direct reaction of the ZnO film and the organic linker vapors, employing a simple route that demonstrates the feasibility of MOF thin film fabrication using inexpensive routes at ambient pressure.

Development of a GNSS water vapour tomography system using algebraic reconstruction techniques

NASA Astrophysics Data System (ADS)

Bender, Michael; Dick, Galina; Ge, Maorong; Deng, Zhiguo; Wickert, Jens; Kahle, Hans-Gert; Raabe, Armin; Tetzlaff, Gerd

2011-05-01

A GNSS water vapour tomography system developed to reconstruct spatially resolved humidity fields in the troposphere is described. The tomography system was designed to process the slant path delays of about 270 German GNSS stations in near real-time with a temporal resolution of 30 min, a horizontal resolution of 40 km and a vertical resolution of 500 m or better. After a short introduction to the GPS slant delay processing the framework of the GNSS tomography is described in detail. Different implementations of the iterative algebraic reconstruction techniques (ART) used to invert the linear inverse problem are discussed. It was found that the multiplicative techniques (MART) provide the best results with least processing time, i.e., a tomographic reconstruction of about 26,000 slant delays on a 8280 cell grid can be obtained in less than 10 min. Different iterative reconstruction techniques are compared with respect to their convergence behaviour and some numerical parameters. The inversion can be considerably stabilized by using additional non-GNSS observations and implementing various constraints. Different strategies for initialising the tomography and utilizing extra information are discussed. At last an example of a reconstructed field of the wet refractivity is presented and compared to the corresponding distribution of the integrated water vapour, an analysis of a numerical weather model (COSMO-DE) and some radiosonde profiles.

Magnesium isotope evidence that accretional vapour loss shapes planetary compositions

PubMed Central

Hin, Remco C.; Coath, Christopher D.; Carter, Philip J.; Nimmo, Francis; Lai, Yi-Jen; Pogge von Strandmann, Philip A.E.; Willbold, Matthias; Leinhardt, Zoë M.; Walter, Michael J.; Elliott, Tim

2017-01-01

It has long been recognised that Earth and other differentiated planetary bodies are chemically fractionated compared to primitive, chondritic meteorites and by inference the primordial disk from which they formed. An important question has been whether the notable volatile depletions of planetary bodies are a consequence of accretion1, or inherited from prior nebular fractionation2. The isotopic compositions of the main constituents of planetary bodies can contribute to this debate3–6. Using a new analytical approach to address key issues of accuracy inherent in conventional methods, we show that all differentiated bodies have isotopically heavier magnesium compositions than chondritic meteorites. We argue that possible magnesium isotope fractionation during condensation of the solar nebula, core formation and silicate differentiation cannot explain these observations. However, isotopic fractionation between liquid and vapour followed by vapour escape during accretionary growth of planetesimals generates appropriate residual compositions. Our modelling implies that the isotopic compositions of Mg, Si and Fe and the relative abundances of the major elements of Earth, and other planetary bodies, are a natural consequence of substantial (~40% by mass) vapour loss from growing planetesimals by this mechanism. PMID:28959965

Land cover change and water vapour flows: learning from Australia.

PubMed Central

Gordon, Line; Dunlop, Michael; Foran, Barney

2003-01-01

Australia is faced with large-scale dryland salinization problems, largely as a consequence of the clearing of native vegetation for cropland and grassland. We estimate the change in continental water vapour flow (evapotranspiration) of Australia during the past 200 years. During this period there has been a substantial decrease in woody vegetation and a corresponding increase in croplands and grasslands. The shift in land use has caused a ca. 10% decrease in water vapour flows from the continent. This reduction corresponds to an annual freshwater flow of almost 340 km(3). The society-induced alteration of freshwater flows is estimated at more than 15 times the volume of run-off freshwater that is diverted and actively managed in the Australian society. These substantial water vapour flow alterations were previously not addressed in water management but are now causing serious impacts on the Australian society and local economies. Global and continental freshwater assessments and policy often neglects the interplay between freshwater flows and landscape dynamics. Freshwater issues on both regional and global levels must be rethought and the interplay between terrestrial ecosystems and freshwater better incorporated in freshwater and ecosystem management. PMID:14728792

Development of a wavelength stabilized seed laser system for an airborne water vapour lidar experiment

NASA Astrophysics Data System (ADS)

Schwarzer, H.; Börner, A.; Fix, A.; Günther, B.; Hübers, H.-W.; Raugust, M.; Schrandt, F.; Wirth, M.

2007-09-01

At the German Aerospace Center an airborne multi-wavelength differential absorption LIDAR for the measurement of atmospheric water vapour is currently under development. This instrument will enable the retrieval of the complete humidity profile from the surface up to the lowermost stratosphere with high vertical and horizontal resolution at a systematic error below 5%. The LIDAR will work in the wavelength region around 935 nm at three different water vapour absorption lines and one reference wavelength. A major sub-system of this instrument is a highly frequency stabilized seed laser system for the optical parametrical oscillators which generate the narrowband high energy light pulses. The development of the seed laser system includes the control software, the electronic control unit and the opto-mechanical layout. The seed lasers are Peltier-cooled distributed feedback laser diodes with bandwidths of about 30 MHz, each one operating for 200 μs before switching to the next one. The required frequency stability is +/- 30 MHz ≅ +/- 10 -4 nm under the rough environmental conditions aboard an aircraft. It is achieved by locking the laser wavelength to a water vapour absorption line. The paper describes the opto-mechanical layout of the seed laser system, the stabilization procedure and the results obtained with this equipment.

On the relationship between atmospheric water vapour transport and extra-tropical cyclones development

NASA Astrophysics Data System (ADS)

Ferreira, Juan A.; Liberato, Margarida L. R.; Ramos, Alexandre M.

2016-08-01

In this study we seek to investigate the role of atmospheric water vapour on the intensification of extra-tropical cyclones over the North Atlantic Ocean and more specifically to investigate the linkage between atmospheric rivers' conditions leading to the explosive development of extra-tropical cyclones. Several WRF-ARW simulations for three recent extra-tropical storms that had major negative socio-economic impacts in the Iberian Peninsula and south-western Europe (Klaus, 2009; Gong, 2013 and Stephanie, 2014) are performed in which the water vapour content of the initial and boundary conditions are tuned. Analyses of the vertically integrated vapour transport show the dependence of the storms' development on atmospheric water vapour. In addition, results also show changes in the shape of the jet stream resulting in a reduction of the upper wind divergence, which in turn affects the intensification of the extra-tropical cyclones studied. This study suggests that atmospheric rivers tend to favour the conditions for explosive extra-tropical storms' development in the three case studies, as simulations performed without the existence of atmospheric rivers produce shallow mid-latitude cyclones, that is, cyclones that are not so intense as those on the reference simulations.

The early summertime Saharan heat low: sensitivity of the radiation budget and atmospheric heating to water vapour and dust aerosol

NASA Astrophysics Data System (ADS)

Alamirew, Netsanet K.; Todd, Martin C.; Ryder, Claire L.; Marsham, John H.; Wang, Yi

2018-01-01

The Saharan heat low (SHL) is a key component of the west African climate system and an important driver of the west African monsoon across a range of timescales of variability. The physical mechanisms driving the variability in the SHL remain uncertain, although water vapour has been implicated as of primary importance. Here, we quantify the independent effects of variability in dust and water vapour on the radiation budget and atmospheric heating of the region using a radiative transfer model configured with observational input data from the Fennec field campaign at the location of Bordj Badji Mokhtar (BBM) in southern Algeria (21.4° N, 0.9° E), close to the SHL core for June 2011. Overall, we find dust aerosol and water vapour to be of similar importance in driving variability in the top-of-atmosphere (TOA) radiation budget and therefore the column-integrated heating over the SHL (˜ 7 W m-2 per standard deviation of dust aerosol optical depth - AOD). As such, we infer that SHL intensity is likely to be similarly enhanced by the effects of dust and water vapour surge events. However, the details of the processes differ. Dust generates substantial radiative cooling at the surface (˜ 11 W m-2 per standard deviation of dust AOD), presumably leading to reduced sensible heat flux in the boundary layer, which is more than compensated by direct radiative heating from shortwave (SW) absorption by dust in the dusty boundary layer. In contrast, water vapour invokes a radiative warming at the surface of ˜ 6 W m-2 per standard deviation of column-integrated water vapour in kg m-2. Net effects involve a pronounced net atmospheric radiative convergence with heating rates on average of 0.5 K day-1 and up to 6 K day-1 during synoptic/mesoscale dust events from monsoon surges and convective cold-pool outflows (haboobs). On this basis, we make inferences on the processes driving variability in the SHL associated with radiative and advective heating/cooling. Depending

The water vapour continuum in near-infrared windows - Current understanding and prospects for its inclusion in spectroscopic databases

NASA Astrophysics Data System (ADS)

Shine, Keith P.; Campargue, Alain; Mondelain, Didier; McPheat, Robert A.; Ptashnik, Igor V.; Weidmann, Damien

2016-09-01

Spectroscopic catalogues, such as GEISA and HITRAN, do not yet include information on the water vapour continuum that pervades visible, infrared and microwave spectral regions. This is partly because, in some spectral regions, there are rather few laboratory measurements in conditions close to those in the Earth's atmosphere; hence understanding of the characteristics of the continuum absorption is still emerging. This is particularly so in the near-infrared and visible, where there has been renewed interest and activity in recent years. In this paper we present a critical review focusing on recent laboratory measurements in two near-infrared window regions (centred on 4700 and 6300 cm-1) and include reference to the window centred on 2600 cm-1 where more measurements have been reported. The rather few available measurements, have used Fourier transform spectroscopy (FTS), cavity ring down spectroscopy, optical-feedback - cavity enhanced laser spectroscopy and, in very narrow regions, calorimetric interferometry. These systems have different advantages and disadvantages. Fourier Transform Spectroscopy can measure the continuum across both these and neighbouring windows; by contrast, the cavity laser techniques are limited to fewer wavenumbers, but have a much higher inherent sensitivity. The available results present a diverse view of the characteristics of continuum absorption, with differences in continuum strength exceeding a factor of 10 in the cores of these windows. In individual windows, the temperature dependence of the water vapour self-continuum differs significantly in the few sets of measurements that allow an analysis. The available data also indicate that the temperature dependence differs significantly between different near-infrared windows. These pioneering measurements provide an impetus for further measurements. Improvements and/or extensions in existing techniques would aid progress to a full characterisation of the continuum - as an example, we

Gravimetric phenotyping of whole plant transpiration responses to atmospheric vapour pressure deficit identifies genotypic variation in water use efficiency.

PubMed

Ryan, Annette C; Dodd, Ian C; Rothwell, Shane A; Jones, Ros; Tardieu, Francois; Draye, Xavier; Davies, William J

2016-10-01

There is increasing interest in rapidly identifying genotypes with improved water use efficiency, exemplified by the development of whole plant phenotyping platforms that automatically measure plant growth and water use. Transpirational responses to atmospheric vapour pressure deficit (VPD) and whole plant water use efficiency (WUE, defined as the accumulation of above ground biomass per unit of water used) were measured in 100 maize (Zea mays L.) genotypes. Using a glasshouse based phenotyping platform with naturally varying VPD (1.5-3.8kPa), a 2-fold variation in WUE was identified in well-watered plants. Regression analysis of transpiration versus VPD under these conditions, and subsequent whole plant gas exchange at imposed VPDs (0.8-3.4kPa) showed identical responses in specific genotypes. Genotype response of transpiration versus VPD fell into two categories: 1) a linear increase in transpiration rate with VPD with low (high WUE) or high (low WUE) transpiration rate at all VPDs, 2) a non-linear response with a pronounced change point at low VPD (high WUE) or high VPD (low WUE). In the latter group, high WUE genotypes required a significantly lower VPD before transpiration was restricted, and had a significantly lower rate of transpiration in response to VPD after this point, when compared to low WUE genotypes. Change point values were significantly positively correlated with stomatal sensitivity to VPD. A change point in stomatal response to VPD may explain why some genotypes show contradictory WUE rankings according to whether they are measured under glasshouse or field conditions. Furthermore, this novel use of a high throughput phenotyping platform successfully reproduced the gas exchange responses of individuals measured in whole plant chambers, accelerating the identification of plants with high WUE. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Inter-arm blood pressure differences in pregnant women.

PubMed

Poon, L C Y; Kametas, N; Strobl, I; Pachoumi, C; Nicolaides, K H

2008-08-01

To determine the prevalence of blood pressure inter-arm difference (IAD) in early pregnancy and to investigate its possible association with maternal characteristics. A cross-sectional observational study. Routine antenatal visit in a university hospital. A total of 5435 pregnant women at 11-14 weeks of gestation. Blood pressure was taken from both arms simultaneously with a validated automated device. The presence of inter-arm blood pressure difference of 10 mmHg or more. The IAD in systolic and diastolic blood pressure was 10 mmHg or more in 8.3 and 2.3% of the women, respectively. Systolic IAD was found to be significantly related to systolic blood pressure and pulse pressure, and diastolic IAD was found to be significantly related to maternal age, diastolic blood pressure and pulse pressure. The systolic and diastolic IAD were higher in the hypertensive group compared with the normotensive group and absolute IAD increased with increasing blood pressure. About 31.0 and 23.9% of cases of hypertension would have been underreported if the left arm and the right arm were used, respectively, in measuring the blood pressure. There is a blood pressure IAD in a significant proportion of the pregnant population, and its prevalence increases with increasing blood pressure. By measuring blood pressure only on one arm, there is a one in three chance of underreporting hypertension. Therefore, it would be prudent that during the booking visit blood pressure should be taken in both arms and thus provide guidance for subsequent blood pressure measurements during the course of pregnancy.

LIFE CYCLE ASSESSMENT OF GASOLINE BLENDING OPTIONS

EPA Science Inventory

A life cycle assessment has been done to compare the potential environmental impacts of various gasoline blends that meet octane and vapour pressure specifications. The main blending components of alkylate, cracked gasoline and reformate have different octane and vapour pressure...

Liquid and vapour-phase antifungal activities of selected essential oils against candida albicans: microscopic observations and chemical characterization of cymbopogon citratus

PubMed Central

2010-01-01

Background Use of essential oils for controlling Candida albicans growth has gained significance due to the resistance acquired by pathogens towards a number of widely-used drugs. The aim of this study was to test the antifungal activity of selected essential oils against Candida albicans in liquid and vapour phase and to determine the chemical composition and mechanism of action of most potent essential oil. Methods Minimum Inhibitory concentration (MIC) of different essential oils in liquid phase, assayed through agar plate dilution, broth dilution & 96-well micro plate dilution method and vapour phase activity evaluated through disc volatilization method. Reduction of C. albicans cells with vapour exposure was estimated by kill time assay. Morphological alteration in treated/untreated C. albicans cells was observed by the Scanning electron microscopy (SEM)/Atomic force microscopy (AFM) and chemical analysis of the strongest antifungal agent/essential oil has been done by GC, GC-MS. Results Lemon grass (Cymbopogon citratus) essential oil exhibited the strongest antifungal effect followed by mentha (Mentha piperita) and eucalyptus (Eucalyptus globulus) essential oil. The MIC of lemon grass essential oil in liquid phase (288 mg/l) was significantly higher than that in the vapour phase (32.7 mg/l) and a 4 h exposure was sufficient to cause 100% loss in viability of C. albicans cells. SEM/AFM of C. albicans cells treated with lemon grass essential oil at MIC level in liquid and vapour phase showed prominent shrinkage and partial degradation, respectively, confirming higher efficacy of vapour phase. GC-MS analysis revealed that lemon grass essential oil was dominated by oxygenated monoterpenes (78.2%); α-citral or geranial (36.2%) and β-citral or neral (26.5%), monoterpene hydrocarbons (7.9%) and sesquiterpene hydrocarbons (3.8%). Conclusion Lemon grass essential oil is highly effective in vapour phase against C. albicans, leading to deleterious morphological

Towards outperforming conventional sensor arrays with fabricated individual photonic vapour sensors inspired by Morpho butterflies

PubMed Central

Potyrailo, Radislav A.; Bonam, Ravi K.; Hartley, John G.; Starkey, Timothy A.; Vukusic, Peter; Vasudev, Milana; Bunning, Timothy; Naik, Rajesh R.; Tang, Zhexiong; Palacios, Manuel A.; Larsen, Michael; Le Tarte, Laurie A.; Grande, James C.; Zhong, Sheng; Deng, Tao

2015-01-01

Combining vapour sensors into arrays is an accepted compromise to mitigate poor selectivity of conventional sensors. Here we show individual nanofabricated sensors that not only selectively detect separate vapours in pristine conditions but also quantify these vapours in mixtures, and when blended with a variable moisture background. Our sensor design is inspired by the iridescent nanostructure and gradient surface chemistry of Morpho butterflies and involves physical and chemical design criteria. The physical design involves optical interference and diffraction on the fabricated periodic nanostructures and uses optical loss in the nanostructure to enhance the spectral diversity of reflectance. The chemical design uses spatially controlled nanostructure functionalization. Thus, while quantitation of analytes in the presence of variable backgrounds is challenging for most sensor arrays, we achieve this goal using individual multivariable sensors. These colorimetric sensors can be tuned for numerous vapour sensing scenarios in confined areas or as individual nodes for distributed monitoring. PMID:26324320

PFS/Mars Express first results: water vapour and carbon monoxide global distribution

NASA Astrophysics Data System (ADS)

Ignatiev, N. I.; Titov, D. V.; Formisano, V.; Moroz, V. I.; Lellouch, E.; Encrenaz, Th.; Fouchet, T.; Grassi, D.; Giuranna, M.; Atreya, S.; Pfs Team

Planetary Fourier Spectrometer onboard Mars Express, with its wide spectral range (1.2--45 um) and high spectral resolution (1.4 cm-1), makes it possible to study in a self-consistent manner the Martian atmosphere by means of simultaneous analysis of spectral features in several spectral regions. As concerned small species, we observe 30--50, 6.3, 2.56, 1.87 and 1.38 μ m H2O bands, and 4.7 and 2.35 μ m CO bands. The most favourable, with respect to the instrument performance, 2.56 μ m H2O and 4.7 μ m CO bands, are used to study the variations of column abundance of water vapour and carbon monoxide on a global scale from pole to pole. All necessary atmospheric parameters, namely temperature profiles, surface pressure, and dust density are obtained from the same spectra, whenever possible.

Roughness and compressive strength of FDM 3D printed specimens affected by acetone vapour treatment

NASA Astrophysics Data System (ADS)

Beniak, Juraj; Križan, Peter; Šooš, Ľubomír; Matúš, Miloš

2018-01-01

Rapid Prototyping technologies are the fastest growing technologies in the manufacturing of components and parts. There are many techniques which can be used with different materials and different purposes of produced part. Gradually, Rapid Prototyping systems have grown into Additive Manufacturing, because technology expansion brings faster production, improved manufactured components, and expanded palette of used materials. So now this techniques are also used for regular production of special parts, where is usual change of part design, where is necessary to produce variety of different designs and shapes. The following article deals with Fused Deposition Modelling (FDM) technology, the core of which is the manufacture models and components from thermoplastic polymers by deposition single fibres of semi-molten plastic material layer by layer. The article focuses on the results of research for testing of manufactured specimens by FDM technology. Components are modified by acetone vapour for surface smoothing. The purpose is to point out how the additional specimen treatment influence the strength properties. Presented paper shows realized experiments and measurements of compressive force on specimens and surface roughness which are influenced by acetone vapour treatment.

A novel hybrid tobacco product that delivers a tobacco flavour note with vapour aerosol (Part 1): Product operation and preliminary aerosol chemistry assessment.

PubMed

Poynton, Simon; Sutton, Joseph; Goodall, Sharon; Margham, Jennifer; Forster, Mark; Scott, Ken; Liu, Chuan; McAdam, Kevin; Murphy, James; Proctor, Christopher

2017-08-01

Vapour products have demonstrated potential to be a lower-risk alternative to cigarettes. The present study describes a novel hybrid tobacco product that combines a warm aerosol stream generated by an electronic vaporisation mechanism with tobacco top flavour from cut tobacco. During operation, the aerosol stream released from the vapour cartomiser is passed through a bed of blended cut tobacco by the puffing flow, elevating the tobacco temperature and eluting volatile tobacco flavour components. A preliminary but comprehensive analysis of the aerosol composition of the hybrid tobacco product found that emissions were dominated by the control vapour formulation. In non-targeted chemical screening, no detectable difference in GC scans was observed between the hybrid tobacco product and the control vapour product. However, a sensorially elevated tobacco flavour was confirmed by a consumer sensory panel (P < 0.05). In a targeted analysis of 113 compounds, either identified by regulatory bodies as potential toxicants in cigarette smoke or formed from electronic vapour products, only 26 were quantified. The novel action of tobacco heating and liquid aerosolisation produced classes and levels of toxicants that were similar to those of the control vapour product, but much lower than those of a Kentucky 3R4F reference cigarette. For nine toxicants mandated by the WHO Study Group on Tobacco Product Regulation for reduction in cigarette emissions, the levels were 91%-99% lower per puff in the hybrid tobacco product aerosol than in 3R4F smoke. Overall, the novel hybrid tobacco product provides a sensorially enhanced tobacco flavour, but maintains a toxicant profile similar to its parent vapour product with relatively low levels of known cigarette smoke toxicants. Copyright © 2017 British American Tobacco. Published by Elsevier Ltd.. All rights reserved.

Introversion associated with large differences between screening blood pressure and home blood pressure measurement: The Ohasama study.

PubMed

Hozawa, Atsushi; Ohkubo, Takayoshi; Obara, Taku; Metoki, Hirohito; Kikuya, Masahiro; Asayama, Kei; Totsune, Kazuhito; Hashimoto, Junichiro; Hoshi, Haruhisa; Arai, Yumiko; Satoh, Hiroshi; Hosokawa, Toru; Imai, Yutaka

2006-11-01

To explore the effect of personality on screening blood pressures measured in clinical settings and home blood pressure measurements. From 1997 to 1999, 699 participants underwent screening and home blood pressure measurements and completed the Japanese version of the short-form Eysenck personality questionnaire. An increased screening blood pressure was defined as screening blood pressure > or = 140/90 mmHg and an increased home blood pressure was defined as home blood pressure > or = 135/85 mmHg. Participants with lower extroversion scores (i.e., introversion) showed a greater difference between screening and home systolic blood pressure. The association between introversion and differences was statistically significant, even after adjustment for other possible factors (younger age, female, wide screening pulse pressure, never smoked, and no antihypertensive medication). The adjusted means of SBP differences were 7.3 and 4.4 mmHg among the lowest and highest extroversion quartiles, respectively (P for trend = 0.02). Other personality scores (psychoticism or neuroticism) were not associated with screening and home blood pressure differences. The incorporation of an extroversion score in the basic model consisting of the above factors that affected the difference between screening and home blood pressure slightly improved the prediction of a high home blood pressure. The area under the receiver operating characteristic curve increased by 0.037 among participants with high screening blood pressure and 0.006 for those with normal screening blood pressure compared with the basic model. Physicians may need to be aware of 'introverted' patients who have high blood pressure in clinic settings, because they have the potential for 'white-coat' hypertension.

Distillation with Vapour Compression. An Undergraduate Experimental Facility.

ERIC Educational Resources Information Center

Pritchard, Colin

1986-01-01

Discusses the need to design distillation columns that are more energy efficient. Describes a "design and build" project completed by two college students aimed at demonstrating the principles of vapour compression distillation in a more energy efficient way. General design specifications are given, along with suggestions for teaching…

Post-wildfire effects on carbon and water vapour dynamics in a Spanish black pine forest.

PubMed

Dadi, T; Rubio, E; Martínez-García, E; López-Serrano, F R; Andrés-Abellán, M; García-Morote, F A; De las Heras, J

2015-04-01

Two eddy covariance systems were installed in a high-severity burned zone (BZ) and an adjacent unburned (UNB) zone to monitor water vapour and carbon dioxide fluxes for 21 months (from June 2011 to February 2013) at a Spanish black pine forest affected by a stand-replacing wildfire and located in a mountainous area of central-eastern Spain. The differences between both sites were significant especially during the growing season, affecting gross primary productivity (GPP) more than ecosystem respiration (Reco). Net ecosystem exchange (NEE) for 2012 was -3.97 and 1.80 t C ha(-1) year(-1) for the unburned and burned sites, respectively, the GPP being 64% lower for the BZ than the UNB zone. Evapotranspiration (ET) at the UNB was 18% greater than at the BZ. Difference between sites was 160 mm during the whole studied period. This study reflects the effect of one of the major disturbances that can affect Mediterranean ecosystems, showing that carbon fluxes are more dramatically concerned than water vapour fluxes.

Ethanol, vinegar and Origanum vulgare oil vapour suppress the development of anthracnose rot in tomato fruit.

PubMed

Tzortzakis, Nikos G

2010-08-15

Anthracnose rot (Colletotrichum coccodes) development in vitro or in tomato (Lycopersicon esculentum L.) fruit was evaluated after treatment with absolute ethyl alcohol (AEA), vinegar (VIN), chlorine (CHL) or origanum oil (ORI) and storage at 12 degrees C and 95% relative humidity during or following exposure to the volatiles. Fruit treated with vapours reduced fungal spore germination/production, but in the case of AEA- and VIN-treated fruits, fungal mycelium development was accelerated. Fruit lesion development was suppressed after fruit exposure to pure (100% v/v) AEA or ORI vapours which were accompanied by increased fruit cracking. Exposure to pure VIN-, CHL- and ORI vapours reduced (up to 92%) spore germination in vitro, but no differences were observed in the AEA treatment. The benefits associated with volatiles-enrichment were maintained in fruit pre-exposed to vapours, resulting in suppression in spore germination and spore production. However, studies performed on fungi grown on Potato Dextrose Agar revealed fewer direct effects of volatiles on fungal colony development and spore germination per se, implying that suppression of pathogen development was due in a large part to the impact of volatiles on fruit-pathogen interactions and/or 'memory' effects on fruit tissue. Work is currently focussing on the mechanisms underlying the impacts of volatiles on fruit quality related attributes. The results of this study indicate that volatiles may be considered as an alternative to the traditional postharvest sanitizing techniques. Each commodity needs to be individually assessed, and the volatile concentration and sanitising technique optimised, before the volatile treatment is used commercially. Copyright 2010 Elsevier B.V. All rights reserved.

Prevalence of inter-arm blood pressure difference among clinical out-patients.

PubMed

Sharma, Balkishan; Ramawat, Pramila

2016-04-01

An increased inter-arm blood pressure difference is an easily determined physical finding, may use as an indicator of cardio vascular event and other sever diseases. Authors evaluated 477 patients to determine the prevalence and significance of inter-arm blood pressure difference. 477 routine outdoor patients selected to observe the inter-arm blood pressure difference. Age, height, weight, body mass index, history of disease and blood pressure recorded. The prevalence of ≥10 mmHg systolic inter-arm blood pressure difference was 5.0% was more as compared to 3.8% had diastolic inter-arm blood pressure difference. The prevalence of systolic and diastolic inter-arm difference between 6 to 10 mmHg was 31.4% and 27.9% respectively. Mean systolic inter-arm blood pressure difference was significantly higher among those patients had a multisystem disorder (10.57±0.98 mmHg) and followed by patients with cardiovascular disease (10.22±0.67 mmHg) as compared to healthy patients (2.71±0.96 mmHg). Various diseases highly influenced the increase in blood pressure irrespective of systolic or diastolic was confirmed strongly significant (p<0.001) at different inter arm blood pressure difference levels. This study supports the view of inter-arm blood pressure difference as an alarming stage of increased disease risk that incorporated to investigate potential problems at an early diagnostic stage. A significant mean difference between left and right arm blood pressure recorded for many diseases.

High efficiency coherent optical memory with warm rubidium vapour

PubMed Central

Hosseini, M.; Sparkes, B.M.; Campbell, G.; Lam, P.K.; Buchler, B.C.

2011-01-01

By harnessing aspects of quantum mechanics, communication and information processing could be radically transformed. Promising forms of quantum information technology include optical quantum cryptographic systems and computing using photons for quantum logic operations. As with current information processing systems, some form of memory will be required. Quantum repeaters, which are required for long distance quantum key distribution, require quantum optical memory as do deterministic logic gates for optical quantum computing. Here, we present results from a coherent optical memory based on warm rubidium vapour and show 87% efficient recall of light pulses, the highest efficiency measured to date for any coherent optical memory suitable for quantum information applications. We also show storage and recall of up to 20 pulses from our system. These results show that simple warm atomic vapour systems have clear potential as a platform for quantum memory. PMID:21285952

High efficiency coherent optical memory with warm rubidium vapour.

PubMed

Hosseini, M; Sparkes, B M; Campbell, G; Lam, P K; Buchler, B C

2011-02-01

By harnessing aspects of quantum mechanics, communication and information processing could be radically transformed. Promising forms of quantum information technology include optical quantum cryptographic systems and computing using photons for quantum logic operations. As with current information processing systems, some form of memory will be required. Quantum repeaters, which are required for long distance quantum key distribution, require quantum optical memory as do deterministic logic gates for optical quantum computing. Here, we present results from a coherent optical memory based on warm rubidium vapour and show 87% efficient recall of light pulses, the highest efficiency measured to date for any coherent optical memory suitable for quantum information applications. We also show storage and recall of up to 20 pulses from our system. These results show that simple warm atomic vapour systems have clear potential as a platform for quantum memory.

Emission characteristics and vapour/particulate phase distributions of PCDD/F in a hazardous waste incinerator under transient conditions

PubMed Central

Wang, Chao; Cen, Kefa; Ni, Mingjiang; Li, Xiaodong

2018-01-01

Polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/F) emission characteristics and vapour/particulate phase partitions under three continued operation conditions, i.e. shut-down, start-up and after start-up, were investigated by sampling stack gas. The results indicated that the PCDD/F emission levels were 0.40–18.03 ng I-TEQ Nm−3, much higher than the annual monitoring level (0.016 ng I-TEQ Nm−3). Additionally, the PCDD/F emission levels in start-up were higher than the other two conditions. Furthermore, the PCDD/F congener profiles differed markedly between shut-down and start-up, and the chlorination degree of PCDD/F increased in shut-down and decreased evidently in start-up. Moreover, PCDD/F vapour/particulate phase distributions varied significantly under three transient conditions. The PCDD/F vapour phase proportion decreased as the shut-down process continued, then increased as the start-up process proceeded, finally more than 98% of the PCDD/F congeners were distributed in the vapour phase after start-up. The correlations between log(Cv/Cs) versus log pL0 of each PCDD/F congener in stack gas were disorganized in shut-down, and trend to a linear distribution after start-up. Besides, polychlorinated biphenyl emissions show behaviour similar to that of PCDD/F, and the lower chlorinated congeners have a stronger relationship with 2,3,7,8-PCDD/Fs, such as M1CB and D2CB. PMID:29410821

A microwave satellite water vapour column retrieval for polar winter conditions

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

Perro, Christopher; Lesins, Glen; Duck, Thomas J.

A new microwave satellite water vapour retrieval for the polar winter atmosphere is presented. The retrieval builds on the work of Miao et al. (2001) and Melsheimer and Heygster (2008), employing auxiliary information for atmospheric conditions and numerical optimization. It was tested using simulated and actual measurements from the Microwave Humidity Sounder (MHS) satellite instruments. Ground truth was provided by the G-band vapour radiometer (GVR) at Barrow, Alaska. For water vapour columns less than 6 kg m -2, comparisons between the retrieval and GVR result in a root mean square (RMS) deviation of 0.39 kg m -2 and a systematic bias of 0.08 kg m -2. These results aremore » compared with RMS deviations and biases at Barrow for the retrieval of Melsheimer and Heygster (2008), the AIRS and MIRS satellite data products, and the ERA-Interim, NCEP, JRA-55, and ASR reanalyses. When applied to MHS measurements, the new retrieval produces a smaller RMS deviation and bias than for the earlier retrieval and satellite data products. The RMS deviations for the new retrieval were comparable to those for the ERA-Interim, JRA-55, and ASR reanalyses; however, the MHS retrievals have much finer horizontal resolution (15 km at nadir) and reveal more structure. The new retrieval can be used to obtain pan-Arctic maps of water vapour columns of unprecedented quality. It may also be applied to measurements from the Special Sensor Microwave/Temperature 2 (SSM/T2), Advanced Microwave Sounding Unit B (AMSU-B), Special Sensor Microwave Imager/Sounder (SSMIS), Advanced Technology Microwave Sounder (ATMS), and Chinese MicroWave Humidity Sounder (MWHS) instruments.« less

Prevalence of inter-arm blood pressure difference among clinical out-patients

PubMed Central

Sharma, Balkishan; Ramawat, Pramila

2016-01-01

Objectives An increased inter-arm blood pressure difference is an easily determined physical finding, may use as an indicator of cardio vascular event and other sever diseases. Authors evaluated 477 patients to determine the prevalence and significance of inter-arm blood pressure difference. Methodology 477 routine outdoor patients selected to observe the inter-arm blood pressure difference. Age, height, weight, body mass index, history of disease and blood pressure recorded. Results The prevalence of ≥10 mmHg systolic inter-arm blood pressure difference was 5.0% was more as compared to 3.8% had diastolic inter-arm blood pressure difference. The prevalence of systolic and diastolic inter-arm difference between 6 to 10 mmHg was 31.4% and 27.9% respectively. Mean systolic inter-arm blood pressure difference was significantly higher among those patients had a multisystem disorder (10.57±0.98 mmHg) and followed by patients with cardiovascular disease (10.22±0.67 mmHg) as compared to healthy patients (2.71±0.96 mmHg). Various diseases highly influenced the increase in blood pressure irrespective of systolic or diastolic was confirmed strongly significant (p<0.001) at different inter arm blood pressure difference levels. Conclusion This study supports the view of inter-arm blood pressure difference as an alarming stage of increased disease risk that incorporated to investigate potential problems at an early diagnostic stage. A significant mean difference between left and right arm blood pressure recorded for many diseases. PMID:27103905

Tropospheric water vapour isotopologue data (H216O, H218O, and HD16O) as obtained from NDACC/FTIR solar absorption spectra

NASA Astrophysics Data System (ADS)

Barthlott, Sabine; Schneider, Matthias; Hase, Frank; Blumenstock, Thomas; Kiel, Matthäus; Dubravica, Darko; García, Omaira E.; Sepúlveda, Eliezer; Mengistu Tsidu, Gizaw; Takele Kenea, Samuel; Grutter, Michel; Plaza-Medina, Eddy F.; Stremme, Wolfgang; Strong, Kim; Weaver, Dan; Palm, Mathias; Warneke, Thorsten; Notholt, Justus; Mahieu, Emmanuel; Servais, Christian; Jones, Nicholas; Griffith, David W. T.; Smale, Dan; Robinson, John

2017-01-01

We report on the ground-based FTIR (Fourier transform infrared) tropospheric water vapour isotopologue remote sensing data that have been recently made available via the database of NDACC (Network for the Detection of Atmospheric Composition Change; ftp://ftp.cpc.ncep.noaa.gov/ndacc/MUSICA/) and via doi:10.5281/zenodo.48902. Currently, data are available for 12 globally distributed stations. They have been centrally retrieved and quality-filtered in the framework of the MUSICA project (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water). We explain particularities of retrieving the water vapour isotopologue state (vertical distribution of H216O, H218O, and HD16O) and reveal the need for a new metadata template for archiving FTIR isotopologue data. We describe the format of different data components and give recommendations for correct data usage. Data are provided as two data types. The first type is best-suited for tropospheric water vapour distribution studies disregarding different isotopologues (comparison with radiosonde data, analyses of water vapour variability and trends, etc.). The second type is needed for analysing moisture pathways by means of H2O, δD-pair distributions.

Long-term series of tropospheric water vapour amounts and HDO/H2O ratio profiles above Jungfraujoch.

NASA Astrophysics Data System (ADS)

Lejeune, B.; Mahieu, E.; Schneider, M.; Hase, F.; Servais, C.; Demoulin, P.

2012-04-01

(Network for the Detection of Atmospheric Composition Change, http://www.ndacc.org) of the Jungfraujoch International Scientific Station (Swiss Alps, 46.5° N, 8.0° E, 3580m asl). Information content analysis of the retrieved H2O products allows us to produce a long-term trend from 1996 to 2011 for different tropospheric levels. We will compare the annual cycle of tropospheric HDO/H2O ratio profiles with those already produced at other sites (Schneider et al., 2010). We will also focus on the diurnal variability of water vapour to determine a time limit in the inter-comparison of different water vapour measurement techniques. Acknowledgments The University of Liège involvement has primarily been supported by the PRODEX program funded by the Belgian Federal Science Policy Office, Brussels and by the Swiss GAW-CH program. The FRS-FNRS and the Fédération Wallonie-Bruxelles are further acknowledged for observational activities support. We thank the International Foundation High Altitude Research Stations Jungfraujoch and Gornergrat (HFSJG, Bern) for supporting the facilities needed to perform the observations. MUSICA is funded by the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013) / ERC Grant agreement n° 256961.

Automatic algorithm for monitoring systolic pressure variation and difference in pulse pressure.

PubMed

Pestel, Gunther; Fukui, Kimiko; Hartwich, Volker; Schumacher, Peter M; Vogt, Andreas; Hiltebrand, Luzius B; Kurz, Andrea; Fujita, Yoshihisa; Inderbitzin, Daniel; Leibundgut, Daniel

2009-06-01

Difference in pulse pressure (dPP) reliably predicts fluid responsiveness in patients. We have developed a respiratory variation (RV) monitoring device (RV monitor), which continuously records both airway pressure and arterial blood pressure (ABP). We compared the RV monitor measurements with manual dPP measurements. ABP and airway pressure (PAW) from 24 patients were recorded. Data were fed to the RV monitor to calculate dPP and systolic pressure variation in two different ways: (a) considering both ABP and PAW (RV algorithm) and (b) ABP only (RV(slim) algorithm). Additionally, ABP and PAW were recorded intraoperatively in 10-min intervals for later calculation of dPP by manual assessment. Interobserver variability was determined. Manual dPP assessments were used for comparison with automated measurements. To estimate the importance of the PAW signal, RV(slim) measurements were compared with RV measurements. For the 24 patients, 174 measurements (6-10 per patient) were recorded. Six observers assessed dPP manually in the first 8 patients (10-min interval, 53 measurements); no interobserver variability occurred using a computer-assisted method. Bland-Altman analysis showed acceptable bias and limits of agreement of the 2 automated methods compared with the manual method (RV: -0.33% +/- 8.72% and RV(slim): -1.74% +/- 7.97%). The difference between RV measurements and RV(slim) measurements is small (bias -1.05%, limits of agreement 5.67%). Measurements of the automated device are comparable with measurements obtained by human observers, who use a computer-assisted method. The importance of the PAW signal is questionable.

Characterization of aqueous interactions of copper-doped phosphate-based glasses by vapour sorption.

PubMed

Stähli, Christoph; Shah Mohammadi, Maziar; Waters, Kristian E; Nazhat, Showan N

2014-07-01

Owing to their adjustable dissolution properties, phosphate-based glasses (PGs) are promising materials for the controlled release of bioinorganics, such as copper ions. This study describes a vapour sorption method that allowed for the investigation of the kinetics and mechanisms of aqueous interactions of PGs of the formulation 50P2O5-30CaO-(20-x)Na2O-xCuO (x=0, 1, 5 and 10mol.%). Initial characterization was performed using (31)P magic angle spinning nuclear magnetic resonance and attenuated total reflectance-Fourier transform infrared spectroscopy. Increasing CuO content resulted in chemical shifts of the predominant Q(2) NMR peak and of the (POP)as and (PO(-)) Fourier transform infrared absorptions, owing to the higher strength of the POCu bond compared to PONa. Vapour sorption and desorption were gravimetrically measured in PG powders exposed to variable relative humidity (RH). Sorption was negligible below 70% RH and increased exponentially with RH from 70 to 90%, where it exhibited a negative correlation with CuO content. Vapour sorption in 0% and 1% CuO glasses resulted in phosphate chain hydration and hydrolysis, as evidenced by protonated Q(0)(1H) and Q(1)(1H) species. Dissolution rates in deionized water showed a linear correlation (R(2)>0.99) with vapour sorption. Furthermore, cation release rates could be predicted based on dissolution rates and PG composition. The release of orthophosphate and short polyphosphate species corroborates the action of hydrolysis and was correlated with pH changes. In conclusion, the agreement between vapour sorption and routine characterization techniques in water demonstrates the potential of this method for the study of PG aqueous reactions. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Warm water vapour in the sooty outflow from a luminous carbon star.

PubMed

Decin, L; Agúndez, M; Barlow, M J; Daniel, F; Cernicharo, J; Lombaert, R; De Beck, E; Royer, P; Vandenbussche, B; Wesson, R; Polehampton, E T; Blommaert, J A D L; De Meester, W; Exter, K; Feuchtgruber, H; Gear, W K; Gomez, H L; Groenewegen, M A T; Guélin, M; Hargrave, P C; Huygen, R; Imhof, P; Ivison, R J; Jean, C; Kahane, C; Kerschbaum, F; Leeks, S J; Lim, T; Matsuura, M; Olofsson, G; Posch, T; Regibo, S; Savini, G; Sibthorpe, B; Swinyard, B M; Yates, J A; Waelkens, C

2010-09-02

The detection of circumstellar water vapour around the ageing carbon star IRC +10216 challenged the current understanding of chemistry in old stars, because water was predicted to be almost absent in carbon-rich stars. Several explanations for the water were postulated, including the vaporization of icy bodies (comets or dwarf planets) in orbit around the star, grain surface reactions, and photochemistry in the outer circumstellar envelope. With a single water line detected so far from this one carbon-rich evolved star, it is difficult to discriminate between the different mechanisms proposed. Here we report the detection of dozens of water vapour lines in the far-infrared and sub-millimetre spectrum of IRC +10216 using the Herschel satellite. This includes some high-excitation lines with energies corresponding to approximately 1,000 K, which can be explained only if water is present in the warm inner sooty region of the envelope. A plausible explanation for the warm water appears to be the penetration of ultraviolet photons deep into a clumpy circumstellar envelope. This mechanism also triggers the formation of other molecules, such as ammonia, whose observed abundances are much higher than hitherto predicted.

Real-time fluorescence quenching-based detection of nitro-containing explosive vapours: what are the key processes?

PubMed

Shaw, P E; Burn, P L

2017-11-15

The detection of explosives continues to be a pressing global challenge with many potential technologies being pursued by the scientific research community. Luminescence-based detection of explosive vapours with an organic semiconductor has attracted much interest because of its potential for detectors that have high sensitivity, compact form factor, simple operation and low-cost. Despite the abundance of literature on novel sensor materials systems there are relatively few mechanistic studies targeted towards vapour-based sensing. In this Perspective, we will review the progress that has been made in understanding the processes that control the real-time luminescence quenching of thin films by analyte vapours. These are the non-radiative quenching process by which the sensor exciton decays, the analyte-sensor intermolecular binding interaction, and the diffusion process for the analyte vapours in the film. We comment on the contributions of each of these processes towards the sensing response and, in particular, the relative roles of analyte diffusion and exciton diffusion. While the latter has been historically judged to be one of, if not the primary, causes for the high sensitivity of many conjugated polymers to nitrated vapours, recent evidence suggests that long exciton diffusion lengths are unnecessary. The implications of these results on the development of sensor materials for real-time detection are discussed.

Solid-state detector system for measuring concentrations of tritiated water vapour and other radioactive gases

NASA Astrophysics Data System (ADS)

Nunes, J. C.; Surette, R. A.; Wood, M. J.

1999-08-01

A detector system was built using a silicon photodiode plus preamplifier and a cesium iodide scintillator plus preamplifier that were commercially available. The potential of the system for measuring concentrations of tritiated water vapour in the presence of other radioactive sources was investigated. For purposes of radiation protection, the sensitivity of the detector system was considered too low for measuring tritiated water vapour concentrations in workplaces such as nuclear power plants. Nevertheless, the spectrometry capability of the system was used successfully to differentiate amongst some radioactive gases in laboratory tests. Although this relatively small system can measure radioactive noble gases as well as tritiated water vapour concentrations, its response to photons remains an issue.

Multifractal comparison of the extremes of rain rates and integrated vapour content

NASA Astrophysics Data System (ADS)

Gires, Auguste; Ni, Vincent; Bosser, Pierre; Tchiguirinskaia, Ioulia; Schertzer, Daniel

2015-04-01

Rainfall extremes are studied through the analyse of three related fields measured with the help of co-located devices installed in the roof of the Ecole des Ponts ParisTech building: (i) Integrated Water Vapour (IWV); it corresponds the amount of water vapour present in the vertical columns between a GPS ground receiver and corresponding satellites. It is estimated from the time shift between the expected duration the signal needs to reach the receiver (the two positions are known) and the actual one (ii) Rain rate measured by three optical disdrometers of two different types (Campbell Scientific PWS100 and OTT Parsivel2) (iii) Relative humidity measured by a dedicated sensor First the correlations between these quantities during significant events is analysed. It appears that although IWV tends to decrease (vapour condense to form drops that fall) and relative humidity to increase during a rainfall event, it turns out difficult to quantitatively characterize this link. It is possibly due to the fact that the scale gap between a punctual measure for the rain rate and an average over a few km height column for the IWV is too large. Finally the scaling features of these three fields are investigated with the help of the Universal Multifractal framework which has been extensively used to analyse and simulate geophysical fields extremely variable over wide ranges of scales. Only three parameters are used to characterize variability across scales: C1 the mean intermittency, alpha the multifractality index and H the non-conservative exponent. Retrieved features are compared and the notion of maximum observable singularity is used to quantify the extremes of the various fields. Authors acknowledge the financial support of the Interreg IV NEW RainGain project (www.raingain.eu) and the chair "hydrology for resilient cities" sponsored by Véolia, and the Climate-KIC Blue Green Dream project (bgd.org.uk/).

Pulse pressure and diabetes treatments: Blood pressure and pulse pressure difference among glucose lowering modality groups in type 2 diabetes.

PubMed

Alemi, Hamid; Khaloo, Pegah; Mansournia, Mohammad Ali; Rabizadeh, Soghra; Salehi, Salome Sadat; Mirmiranpour, Hossein; Meftah, Neda; Esteghamati, Alireza; Nakhjavani, Manouchehr

2018-02-01

Type 2 diabetes is associated with higher pulse pressure. In this study, we assessed and compared effects of classic diabetes treatments on pulse pressure (PP), systolic blood pressure (SBP), and diastolic blood pressure (DBP) in patients with type 2 diabetes.In a retrospective cohort study, 718 non-hypertensive patients with type 2 diabetes were selected and divided into 4 groups including metformin, insulin, glibenclamide+metformin, and metformin+insulin. They were followed for 4 consecutive visits lasting about 45.5 months. Effects of drug regimens on pulse and blood pressure over time were assessed separately and compared in regression models with generalized estimating equation method and were adjusted for age, duration of diabetes, sex, smoking, and body mass index (BMI).Studied groups had no significant change in PP, SBP, and DBP over time. No significant difference in PP and DBP among studied groups was observed (PP:P = 0.090; DBP:P = 0.063). Pairwise comparisons of PP, SBP, and DBP showed no statistically significant contrast between any 2 studied groups. Interactions of time and treatment were not different among groups.Our results demonstrate patients using metformin got higher PP and SBP over time. Averagely, pulse and blood pressure among groups were not different. Trends of variation in pulse and blood pressure were not different among studied diabetes treatments.

Rapid, optical measurement of the atmospheric pressure on a fast research aircraft using open-path TDLAS

NASA Astrophysics Data System (ADS)

Buchholz, B.; Afchine, A.; Ebert, V.

2014-05-01

Because of the high travel speed, the complex flow dynamics around an aircraft and the complex dependency of the fluid dynamics on numerous airborne parameters, it is quite difficult to obtain accurate pressure values at a specific instrument location of an aircraft's fuselage. Complex simulations using computational fluid dynamics (CFD) models can in theory computationally "transfer" pressure values from one location to another. However, for long flight patterns, this process is inconvenient and cumbersome. Furthermore these CFD transfer models require a local experimental validation, which is rarely available. In this paper, we describe an integrated approach for a spectroscopic, calibration-free, in-flight pressure determination in an open-path White cell on an aircraft fuselage using ambient, atmospheric water vapour as the "sensor species". The presented measurements are realized with the HAI (Hygrometer for Atmospheric Investigations) instrument, built for multiphase water detection via calibration-free TDLAS (tunable diode laser absorption spectroscopy). The pressure determination is based on raw data used for H2O concentration measurement, but with a different post-flight evaluation method, and can therefore be conducted at deferred time intervals on any desired flight track. The spectroscopic pressure is compared in-flight with the static ambient pressure of the aircraft avionic system and a micro-mechanical pressure sensor, located next to the open-path cell, over a pressure range from 150 hPa to 800 hPa, and a water vapour concentration range of more than three orders of magnitude. The correlation between the micro-mechanical pressure sensor measurements and the spectroscopic pressure measurements show an average deviation from linearity of only 0.14% and a small offset of 9.5 hPa. For the spectroscopic pressure evaluation we derive measurement uncertainties under laboratory conditions of 3.2% and 5.1% during in flight operation on the HALO airplane

Rapid, optical measurement of the atmospheric pressure on a fast research aircraft using open-path TDLAS

NASA Astrophysics Data System (ADS)

Buchholz, B.; Afchine, A.; Ebert, V.

2014-11-01

Because of the high travel speed, the complex flow dynamics around an aircraft, and the complex dependency of the fluid dynamics on numerous airborne parameters, it is quite difficult to obtain accurate pressure values at a specific instrument location of an aircraft's fuselage. Complex simulations using computational fluid dynamics (CFD) models can in theory computationally "transfer" pressure values from one location to another. However, for long flight patterns, this process is inconvenient and cumbersome. Furthermore, these CFD transfer models require a local experimental validation, which is rarely available. In this paper, we describe an integrated approach for a spectroscopic, calibration-free, in-flight pressure determination in an open-path White cell on an aircraft fuselage using ambient, atmospheric water vapour as the "sensor species". The presented measurements are realised with the HAI (Hygrometer for Atmospheric Investigations) instrument, built for multiphase water detection via calibration-free TDLAS (tunable diode laser absorption spectroscopy). The pressure determination is based on raw data used for H2O concentration measurement, but with a different post-flight evaluation method, and can therefore be conducted at deferred time intervals on any desired flight track. The spectroscopic pressure is compared in-flight with the static ambient pressure of the aircraft avionic system and a micro-mechanical pressure sensor, located next to the open-path cell, over a pressure range from 150 to 800 hPa, and a water vapour concentration range of more than 3 orders of magnitude. The correlation between the micro-mechanical pressure sensor measurements and the spectroscopic pressure measurements shows an average deviation from linearity of only 0.14% and a small offset of 9.5 hPa. For the spectroscopic pressure evaluation we derive measurement uncertainties under laboratory conditions of 3.2 and 5.1% during in-flight operation on the HALO airplane. Under

Formation of formic acid and organic peroxides in the ozonolysis of ethene with added water vapour

NASA Astrophysics Data System (ADS)

Horie, Osamu; Neeb, Peter; Limbach, Stefan; Moortgat, Geert K.

1994-07-01

Ozonolysis of C2H4 was carried out in a 580 l glass reaction vessel at 1-5 ppm reactant concentrations, with added water vapour. Under dry conditions ([H2O]0 = 0.5 ppm), HCHO, CO, CO2, (CHO)2O (formic acid anhydride), H2O2, and CH3OOH were identified as the reaction products. Under wet conditions ([H2O]0 = 2 × 104 ppm), HCOOH yields approaching ca. 20% of the converted C2H4, were observed, while no (CHO)2O was formed. Hydroxymethyl hydroperoxide, HOCH2OOH, was observed as the major peroxide, and found to be formed only in the presence of water vapour. Direct reactions of H2O vapour with the excited CH2OO* radicals and with stabilized CH2OO radicals are postulated to explain the formation of HCOOH and HOCH2OOH in the presence of water vapour, respectively.

Sorbent Film-Coated Passive Samplers for Explosives Vapour Detection Part A: Materials Optimisation and Integration with Analytical Technologies.

PubMed

McEneff, Gillian L; Murphy, Bronagh; Webb, Tony; Wood, Dan; Irlam, Rachel; Mills, Jim; Green, David; Barron, Leon P

2018-04-11

A new thin-film passive sampler is presented as a low resource dependent and discrete continuous monitoring solution for explosives-related vapours. Using 15 mid-high vapour pressure explosives-related compounds as probes, combinations of four thermally stable substrates and six film-based sorbents were evaluated. Meta-aramid and phenylene oxide-based materials showed the best recoveries from small voids (~70%). Analysis was performed using liquid chromatography-high resolution accurate mass spectrometry which also enabled tentative identification of new targets from the acquired data. Preliminary uptake kinetics experiments revealed plateau concentrations on the device were reached between 3-5 days. Compounds used in improvised explosive devices, such as triacetone triperoxide, were detected within 1 hour and were stably retained by the sampler for up to 7 days. Sampler performance was consistent for 22 months after manufacture. Lastly, its direct integration with currently in-service explosives screening equipment including ion mobility spectrometry and thermal desorption mass spectrometry is presented. Following exposure to several open environments and targeted interferences, sampler performance was subsequently assessed and potential interferences identified. High-security building and area monitoring for concealed explosives using such cost-effective and discrete passive samplers can add extra assurance to search routines while minimising any additional burden on personnel or everyday site operation.

An advanced expiratory circuit for the recovery of perfluorocarbon liquid from non-saturated perfluorocarbon vapour during partial liquid ventilation: an experimental model

PubMed Central

Dunster, Kimble R; Davies, Mark W; Fraser, John F

2006-01-01

Background The loss of perfluorocarbon (PFC) vapour in the expired gases during partial liquid ventilation should be minimized both to prevent perfluorocarbon vapour entering the atmosphere and to re-use the recovered PFC liquid. Using a substantially modified design of our previously described condenser, we aimed to determine how much perfluorocarbon liquid could be recovered from gases containing PFC and water vapour, at concentrations found during partial liquid ventilation, and to determine if the amount recovered differed with background flow rate (at flow rates suitable for use in neonates). Methods The expiratory line of a standard ventilator circuit set-up was mimicked, with the addition of two condensers. Perfluorocarbon (30 mL of FC-77) and water vapour, at concentrations found during partial liquid ventilation, were passed through the circuit at a number of flow rates and the percentage recovery of the liquids measured. Results From 14.2 mL (47%) to 27.3 mL (91%) of the infused 30 mL of FC-77 was recovered at the flow rates studied. Significantly higher FC-77 recovery was obtained at lower flow rates (ANOVA with Bonferroni's multiple comparison test, p < 0.0001). As a percentage of the theoretical maximum recovery, 64 to 95% of the FC-77 was recovered. Statistically significantly less FC-77 was recovered at 5 Lmin-1 (ANOVA with Bonferroni's multiple comparison test, p < 0.0001). Amounts of perfluorocarbon vapour recovered were 47%, 50%, 81% and 91% at flow rates of 10, 5, 2 and 1 Lmin-1, respectively. Conclusion Using two condensers in series 47% to 91% of perfluorocarbon liquid can be recovered, from gases containing perfluorocarbon and water vapour, at concentrations found during partial liquid ventilation. PMID:16457722

Concurrent growth of InSe wires and In2O3 tulip-like structures in the Au-catalytic vapour-liquid-solid process

NASA Astrophysics Data System (ADS)

Taurino, A.; Signore, M. A.

2015-06-01

In this work, the concurrent growth of InSe and In2O3 nanostructures, obtained by thermal evaporation of InSe powders on Au-covered Si substrates, has been investigated by scanning and transmission electron microscopy techniques. The vapour-solid and Au catalytic vapour-liquid-solid growth mechanisms, responsible of the simultaneous development of the two different types of nanostructures, i.e. InSe wires and In2O3 tulip-like structures respectively, are discussed in detail. The thermodynamic processes giving rise to the obtained morphologies and materials are explained.

3D imaging of vapour and liquid inclusions from the Mole Granite, Australia, using helical fluorescence tomography

NASA Astrophysics Data System (ADS)

Cauzid, J.; Philippot, P.; Bleuet, P.; Simionovici, A.; Somogyi, A.; Golosio, B.

2007-08-01

World class Cu resources are concentrated in porphyry and epithermal ore deposits. Their formation remains partially understood, however, due to a lack of constraints on the partitioning properties of trace elements in general, and Cu in particular, between vapour and liquid phases evolved from boiling fluids at depth in the Earth's crust. Immiscible liquid and vapour fluid inclusions coexisting in a single quartz grain have been imaged in three dimensions by X-ray Fluorescence Computed Tomography (XFCT). Elemental spatial distributions confirm that Cu, and to a lesser extent As, partition into the vapour phase, whereas Mn, Fe, Zn, Br, Rb, Sr and Pb concentrate in the liquid inclusion. High resolution mapping of the vapour inclusions revealed that Cu is heterogeneously distributed at the scale of a single inclusion and is mostly concentrated as tiny daughter crystals.

Swelling behaviour of Early Jurassic shales when exposed to water vapour

NASA Astrophysics Data System (ADS)

Houben, Maartje; Barnhoorn, Auke; Peach, Colin; Drury, Martyn

2017-04-01

The presence of water in mudrocks has a largely negative impact on production of gas, due to the fact that water causes swelling of the rock. Removing the water from the mudrock on the other hand could potentially shrink the rock and increase the matrix permeability. Investigation of the swelling/shrinkage behaviour of the rock during exposure to water vapour is of key importance in designing and optimizing unconventional production strategies. We have used outcrop samples of the Whitby Mudstone and the Posidonia shale [1], potential unconventional sources for gas in North-western Europe, to measure the swelling and shrinkage behaviour. Subsamples, 1 mm cubes, were prepared by the Glass Workshop at Utrecht University using a high precision digitally controlled diamond wafering saw cooled by air. The mm cubes were then exposed to atmospheres with different relative humidities either in an Environmental Scanning Electron Microscope (ESEM) or in a 3D dilatometer. So that the sample responses to exposure of water vapour could be measured. Parallel to the bedding we found a swelling strain between 0.5 and 1.5 %, perpendicular to the bedding though swelling strain varied between 1 and 3.5%. Volumetric swelling strain varied between 1 and 2% at a maximum relative humidity of 95%. Volumetric swelling strains measured in the Early Toarcian Shales are similar to the ones found in coal [2], where the results suggest that it might be possible to increase permeability in the reservoir by decreasing the in-situ water activity due to shrinkage of the matrix. [1] M.E. Houben, A. Barnhoorn, L. Wasch, J. Trabucho-Alexandre, C. J. Peach, M.R. Drury (2016). Microstructures of Early Jurassic (Toarcian) shales of Northern Europe, International Journal of Coal Geology, 165, 76-89. [2] Jinfeng Liu, Colin J. Peach, Christopher J. Spiers (2016). Anisotropic swelling behaviour of coal matrix cubes exposed to water vapour: Effects of relative humidity and sample size, International Journal of

Modelling of gas-metal arc welding taking into account metal vapour

NASA Astrophysics Data System (ADS)

Schnick, M.; Fuessel, U.; Hertel, M.; Haessler, M.; Spille-Kohoff, A.; Murphy, A. B.

2010-11-01

The most advanced numerical models of gas-metal arc welding (GMAW) neglect vaporization of metal, and assume an argon atmosphere for the arc region, as is also common practice for models of gas-tungsten arc welding (GTAW). These models predict temperatures above 20 000 K and a temperature distribution similar to GTAW arcs. However, spectroscopic temperature measurements in GMAW arcs demonstrate much lower arc temperatures. In contrast to measurements of GTAW arcs, they have shown the presence of a central local minimum of the radial temperature distribution. This paper presents a GMAW model that takes into account metal vapour and that is able to predict the local central minimum in the radial distributions of temperature and electric current density. The influence of different values for the net radiative emission coefficient of iron vapour, which vary by up to a factor of hundred, is examined. It is shown that these net emission coefficients cause differences in the magnitudes, but not in the overall trends, of the radial distribution of temperature and current density. Further, the influence of the metal vaporization rate is investigated. We present evidence that, for higher vaporization rates, the central flow velocity inside the arc is decreased and can even change direction so that it is directed from the workpiece towards the wire, although the outer plasma flow is still directed towards the workpiece. In support of this thesis, we have attempted to reproduce the measurements of Zielińska et al for spray-transfer mode GMAW numerically, and have obtained reasonable agreement.

Dichlorvos vapour disinsection of aircraft

PubMed Central

Jensen, Jens A.; Flury, Vincent P.; Schoof, Herbert F.

1965-01-01

The authors describe the testing of an automatic aircraft disinsection system permanently installed on a commercial DC-6B passenger aircraft. An air-compressor forces ambient cabin air, partially saturated with dichlorvos vapour at a set concentration, through the cabin, cockpit and baggage compartments of the aircraft for 30 minutes. Insecticide concentrations and insect mortality were observed in post-overhaul check flights, and insect mortality and passenger reactions were observed on scheduled flights between Miami, Florida, and Nassau, Bahamas. The results showed satisfactory biological efficiency. The passengers were unaware of the disinsection process and showed no signs of discomfort. ImagesFIG. 1FIG. 2FIG. 3 PMID:14310904

Oscillatory vapour shielding of liquid metal walls in nuclear fusion devices.

PubMed

van Eden, G G; Kvon, V; van de Sanden, M C M; Morgan, T W

2017-08-04

Providing an efficacious plasma facing surface between the extreme plasma heat exhaust and the structural materials of nuclear fusion devices is a major challenge on the road to electricity production by fusion power plants. The performance of solid plasma facing surfaces may become critically reduced over time due to progressing damage accumulation. Liquid metals, however, are now gaining interest in solving the challenge of extreme heat flux hitting the reactor walls. A key advantage of liquid metals is the use of vapour shielding to reduce the plasma exhaust. Here we demonstrate that this phenomenon is oscillatory by nature. The dynamics of a Sn vapour cloud are investigated by exposing liquid Sn targets to H and He plasmas at heat fluxes greater than 5 MW m -2 . The observations indicate the presence of a dynamic equilibrium between the plasma and liquid target ruled by recombinatory processes in the plasma, leading to an approximately stable surface temperature.Vapour shielding is one of the interesting mechanisms for reducing the heat load to plasma facing components in fusion reactors. Here the authors report on the observation of a dynamic equilibrium between the plasma and the divertor liquid Sn surface leading to an overall stable surface temperature.

Oxidation of volatile organic vapours in air by solid potassium permanganate.

PubMed

Mahmoodlu, Mojtaba Ghareh; Hartog, Niels; Majid Hassanizadeh, S; Raoof, Amir

2013-06-01

Volatile organic compounds (VOCs) may frequently contaminate groundwater and pose threat to human health when migrating into the unsaturated soil zone and upward to the indoor air. The kinetic of chemical oxidation has been investigated widely for dissolved VOCs in the saturated zone. But, so far there have been few studies on the use of in situ chemical oxidation (ISCO) of vapour phase contaminants. In this study, batch experiments were carried out to evaluate the oxidation of trichloroethylene (TCE), ethanol, and toluene vapours by solid potassium permanganate. Results revealed that solid potassium permanganate is able to transform the vapour of these compounds into harmless oxidation products. The degradation rates for TCE and ethanol were higher than for toluene. The degradation process was modelled using a kinetic model, linear in the gas concentration of VOC [ML(-3)] and relative surface area of potassium permanganate grains (surface area of potassium permanganate divided by gas volume) [L(-1)]. The second-order reaction rate constants for TCE, ethanol, and toluene were found to be equal to 2.0×10(-6) cm s(-1), 1.7×10(-7) cm s(-1), and 7.0×10(-8) cm s(-1), respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

Highly efficient solar vapour generation via hierarchically nanostructured gels.

PubMed

Zhao, Fei; Zhou, Xingyi; Shi, Ye; Qian, Xin; Alexander, Megan; Zhao, Xinpeng; Mendez, Samantha; Yang, Ronggui; Qu, Liangti; Yu, Guihua

2018-04-02

Solar vapour generation is an efficient way of harvesting solar energy for the purification of polluted or saline water. However, water evaporation suffers from either inefficient utilization of solar energy or relies on complex and expensive light-concentration accessories. Here, we demonstrate a hierarchically nanostructured gel (HNG) based on polyvinyl alcohol (PVA) and polypyrrole (PPy) that serves as an independent solar vapour generator. The converted energy can be utilized in situ to power the vaporization of water contained in the molecular meshes of the PVA network, where water evaporation is facilitated by the skeleton of the hydrogel. A floating HNG sample evaporated water with a record high rate of 3.2 kg m -2  h -1 via 94% solar energy from 1 sun irradiation, and 18-23 litres of water per square metre of HNG was delivered daily when purifying brine water. These values were achievable due to the reduced latent heat of water evaporation in the molecular mesh under natural sunlight.

Highly efficient solar vapour generation via hierarchically nanostructured gels

NASA Astrophysics Data System (ADS)

Zhao, Fei; Zhou, Xingyi; Shi, Ye; Qian, Xin; Alexander, Megan; Zhao, Xinpeng; Mendez, Samantha; Yang, Ronggui; Qu, Liangti; Yu, Guihua

2018-06-01

Solar vapour generation is an efficient way of harvesting solar energy for the purification of polluted or saline water. However, water evaporation suffers from either inefficient utilization of solar energy or relies on complex and expensive light-concentration accessories. Here, we demonstrate a hierarchically nanostructured gel (HNG) based on polyvinyl alcohol (PVA) and polypyrrole (PPy) that serves as an independent solar vapour generator. The converted energy can be utilized in situ to power the vaporization of water contained in the molecular meshes of the PVA network, where water evaporation is facilitated by the skeleton of the hydrogel. A floating HNG sample evaporated water with a record high rate of 3.2 kg m-2 h-1 via 94% solar energy from 1 sun irradiation, and 18-23 litres of water per square metre of HNG was delivered daily when purifying brine water. These values were achievable due to the reduced latent heat of water evaporation in the molecular mesh under natural sunlight.

Different origins of garnet in high pressure to ultrahigh pressure metamorphic rocks

NASA Astrophysics Data System (ADS)

Xia, Qiong-Xia; Zhou, Li-Gang

2017-09-01

Garnet in high-pressure (HP) to ultrahigh-pressure (UHP) metamorphic rocks in subduction zone commonly shows considerable zonation in major and trace elements as well as mineral inclusions, which bears information on its growth mechanism via metamorphic or peritectic reactions in coexistence with relic minerals and metamorphic fluids or anatectic melts at subduction-zone conditions. It provides an important target to retrieve physicochemical changes in subduction-zone processes, including those not only in pressure and temperature but also in the durations of metamorphism and anatexis. Garnet from different compositions of HP to UHP metamorphic rocks may show different types of major and trace element zonation, as well as mineral inclusions. Discrimination between the different origins of garnet provides important constraints on pressure and temperature and the evolution history for the HP to UHP metamorphic rocks. Magmatic garnet may occur as relics in granitic gneisses despite metamorphic modification at subduction-zone conditions, with spessartine-increasing or flat major element profiles from inner to outer core and exceptionally higher contents of trace elements than metamorphic mantle and rim. Metamorphic garnet can grow at different metamorphic stages during prograde subduction and retrograde exhumation, with spessartine-decreasing from core to rim if the intracrystalline diffusion is not too fast. The compositional profiles of metamorphic garnet in the abundances of grossular, almandine and pyrope are variable depending on the composition of host rocks and co-existing minerals. Peritectic garnet grows through peritectic reactions during partial melting of HP to UHP rocks, with the composition of major elements to be controlled by anatectic P-T conditions and the compositions of parental rocks and anatectic melts. Trace element profiles in garnet with different origins are also variable depending on the coexisting mineral assemblages, the garnet

Drivers of radial growth and carbon isotope discrimination of bur oak (Quercus macrocarpa Michx.) across continental gradients in precipitation, vapour pressure deficit and irradiance.

PubMed

Voelker, Steven L; Meinzer, Frederick C; Lachenbruch, Barbara; Brooks, J Renée; Guyette, Richard P

2014-03-01

Tree-ring characteristics are commonly used to reconstruct climate variables, but divergence from the assumption of a single biophysical control may reduce the accuracy of these reconstructions. Here, we present data from bur oaks (Quercus macrocarpa Michx.) sampled within and beyond the current species bioclimatic envelope to identify the primary environmental controls on ring-width indices (RWIs) and carbon stable isotope discrimination (Δ(13) C) in tree-ring cellulose. Variation in Δ(13) C and RWI was more strongly related to leaf-to-air vapour pressure deficit (VPD) at the centre and western edge of the range compared with the northern and wettest regions. Among regions, Δ(13) C of tree-ring cellulose was closely predicted by VPD and light responses of canopy-level Δ(13) C estimated using a model driven by eddy flux and meteorological measurements (R(2)  = 0.96, P = 0.003). RWI and Δ(13) C were positively correlated in the drier regions, while they were negatively correlated in the wettest region. The strength and direction of the correlations scaled with regional VPD or the ratio of precipitation to evapotranspiration. Therefore, the correlation strength between RWI and Δ(13) C may be used to infer past wetness or aridity from paleo wood by determining the degree to which carbon gain and growth have been more limited by moisture or light. © 2013 John Wiley & Sons Ltd.

Retrieval of total water vapour in the Arctic using microwave humidity sounders

NASA Astrophysics Data System (ADS)

Cristian Scarlat, Raul; Melsheimer, Christian; Heygster, Georg

2018-04-01

Quantitative retrievals of atmospheric water vapour in the Arctic present numerous challenges because of the particular climate characteristics of this area. Here, we attempt to build upon the work of Melsheimer and Heygster (2008) to retrieve total atmospheric water vapour (TWV) in the Arctic from satellite microwave radiometers. While the above-mentioned algorithm deals primarily with the ice-covered central Arctic, with this work we aim to extend the coverage to partially ice-covered and ice-free areas. By using modelled values for the microwave emissivity of the ice-free sea surface, we develop two sub-algorithms using different sets of channels that deal solely with open-ocean areas. The new algorithm extends the spatial coverage of the retrieval throughout the year but especially in the warmer months when higher TWV values are frequent. The high TWV measurements over both sea-ice and open-water surfaces are, however, connected to larger uncertainties as the retrieval values are close to the instrument saturation limits.This approach allows us to apply the algorithm to regions where previously no data were available and ensures a more consistent physical analysis of the satellite measurements by taking into account the contribution of the surface emissivity to the measured signal.

Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS) through laboratory studies of inorganic species

NASA Astrophysics Data System (ADS)

Hu, Weiwei; Campuzano-Jost, Pedro; Day, Douglas A.; Croteau, Philip; Canagaratna, Manjula R.; Jayne, John T.; Worsnop, Douglas R.; Jimenez, Jose L.

2017-08-01

Aerosol mass spectrometers (AMSs) and Aerosol Chemical Speciation Monitors (ACSMs) commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV) that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE) to correct for the loss of particles due to bounce. A new capture vapourizer (CV) has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in the laboratory. Four standard species, NH4NO3, NaNO3, (NH4)2SO4 and NH4Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature (Tv ˜ 200-800 °C) on the detected fragments, CE and size distributions are investigated. A Tv of 500-550 °C for the CV is recommended. In the CV, CE was identical (around unity) for more volatile species (e.g. NH4NO3) and comparable to or higher than the SV for less-volatile species (e.g. (NH4)2SO4), demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO3 and SO4 species observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO2(g) from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH4NO3 and comparable to the SV for NaNO3. . We observe an extremely consistent fragmentation for ammonium compared to very large changes for the

THE INTERACTION OF VAPOUR PHASE ORGANIC COMPOUNDS WITH INDOOR SINKS

EPA Science Inventory

The interaction of indoor air pollutants with interior surfaces (i.e., sinks) is a well known, but poorly understood, phenomenon. Studies have shown that re-emissions of adsorbed organic vapours can contribute to elevated concentrations of organics in indoor environments. Researc...

Study of Laser Created Metal Vapour Plasmas.

DTIC Science & Technology

1981-09-01

ance saturation could lead to extensive ground Zcvei burnout of certain kinds of atoms or ions and that this could lead to the creation of a ground...level FORM DD I JAN ", 1473 UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PACE ’l hen Dota Fnt ’UNCLASSIFIFD SS ~eUItTY CLASSIFICATION OF THIS PAqE(W"Sef...vapours. Preliminary calculations have suggested that laser resonance saturation could lead to extensive ground level burnout of certain kinds of

Formation of nanodiamonds at near-ambient conditions via microplasma dissociation of ethanol vapour.

PubMed

Kumar, Ajay; Ann Lin, Pin; Xue, Albert; Hao, Boyi; Khin Yap, Yoke; Sankaran, R Mohan

2013-01-01

Clusters of diamond-phase carbon, known as nanodiamonds, exhibit novel mechanical, optical and biological properties that have elicited interest for a wide range of technological applications. Although diamond is predicted to be more stable than graphite at the nanoscale, extreme environments are typically used to produce nanodiamonds. Here we show that nanodiamonds can be stably formed in the gas phase at atmospheric pressure and neutral gas temperatures <100 °C by dissociation of ethanol vapour in a novel microplasma process. Addition of hydrogen gas to the process allows in flight purification by selective etching of the non-diamond carbon and stabilization of the nanodiamonds. The nanodiamond particles are predominantly between 2 and 5 nm in diameter, and exhibit cubic diamond, n-diamond and lonsdaleite crystal structures, similar to nanodiamonds recovered from meteoritic residues. These results may help explain the origin of nanodiamonds in the cosmos, and offer a simple and inexpensive route for the production of high-purity nanodiamonds.

Diurnal patterns in Scots pine stem oleoresin pressure in a boreal forest.

PubMed

Rissanen, K; Hölttä, T; Vanhatalo, A; Aalto, J; Nikinmaa, E; Rita, H; Bäck, J

2016-03-01

Coniferous tree stems contain large amounts of oleoresin under positive pressure in the resin ducts. Studies in North-American pines indicated that the stem oleoresin exudation pressure (OEP) correlates negatively with transpiration rate and soil water content. However, it is not known how the OEP changes affect the emissions of volatile vapours from the trees. We measured the OEP, xylem diameter changes indicating changes in xylem water potential and monoterpene emissions under field conditions in mature Scots pine (Pinus sylvestris L.) trees in southern Finland. Contrary to earlier reports, the diurnal OEP changes were positively correlated with temperature and transpiration rate. OEP was lowest at the top part of the stem, where water potentials were also more negative, and often closely linked to ambient temperature and stem monoterpene emissions. However, occasionally OEP was affected by sudden changes in vapour pressure deficit (VPD), indicating the importance of xylem water potential on OEP as well. We conclude that the oleoresin storage pools in tree stems are in a dynamic relationship with ambient temperature and xylem water potential, and that the canopy monoterpene emission rates may therefore be also regulated by whole tree processes and not only by the conditions prevailing in the upper canopy. © 2015 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

Infrared Laser Optoacoustic Detection Of Gases And Vapours

NASA Astrophysics Data System (ADS)

Johnson, S. A.; Cummins, P. G.; Bone, S. A.; Davies, P. B.

1988-10-01

Mid-infrared laser optoacoustic spectroscopy has been used to detect a variety of gases and vapours. Performance was calibrated using the signal from a known concentration of ethene, and then the method applied to the perfume alcohol geraniol. Detection limits were found to be 1 ppb for ethene and 70 ppb for geraniol on their strongest absorption lines for a few seconds measurement time.

Influence of water vapour and permanent gases on the atmospheric optical depths and transmittance

NASA Astrophysics Data System (ADS)

Badescu, V.

1991-05-01

The influence of the atmospheric state on the extinction of direct solar radiation has been studied by using a four layer atmospheric model. Simple analytical formulae are established for the spectral optical depths of permanent gases and water vapour. These formulae use the ground level values of air pressure, temperature and relative huniidity. An additional parameter, related to the vertical distribution of the hunmidity content, is used for a better estimation of the water vapour optical depth. Good agreement between theory and measurements is found. The paper shows the dependence of the atmospheric spectral transmittance on the above mentioned parameters. L'influence de l'état atmosphérique sur l'extinction de la radiation solaire directe a été étudiée à l'aide d'un modèle atmosphérique développé antérieurement par l'auteur. Des formules simples ont été établies pour l'épaisseur optique spectrale des gaz et de la vapeur d'eau. Ces formules utilisent les valeurs de la pression atmosphérique, de la température et de l'humidité relative, mesurées au niveau du sol. Un paramètre supplémentaire, lié à la distribution verticale du contenu d'humidité, est utilisé pour calculer l'épaisseur optique due à la vapeur d'eau. La théorie est en bon accord avec les résultats des mesures. Le travail montre la dépendance de la transmittance atmosphérique spectrale en fonction des paramètres spécifiés ci-dessus.

The effect of ethanol vapour exposure on atrial and ventricular walls of chick embryos.

PubMed

Kamran, Kiran; Khan, Muhammad Yunus; Minhas, Liaqat Ali

2016-10-01

To study the effects of ethanol vapour exposure on atrial and ventricular walls of heart in chick embryo. The study design was experimental, conducted at Islamabad Centre of College of Physicians and Surgeons, Pakistan. One hundred and eighty chicken eggs were divided into two groups, experimental and control, of 90 eggs each. Each group was subdivided into three subgroups of 30 eggs each based on the day of sacrifice. Experimental group was exposed to ethanol vapours and then compared with age matched controls. The thickness of atrial and ventricular walls along with lengths of valvular cusps increased in hearts of day 7 and day 10 chick embryos in experimental group. There was thinning of walls and decreased length of valvular cusps in hearts of experimental chicks on hatching as compared to age matched controls. Ethanol vapour exposure during development causes cardiac and septal wall thickening during initial days of development followed by cardiac and septal wall thinning which is a classical picture of alcohol induced cardiomyopathies.

Thermally decarboxylated sodium bicarbonate: Interactions with water vapour, calorimetric study

PubMed Central

Volkova, Natalia; Hansson, Henri; Ljunggren, Lennart

2012-01-01

Isothermal titration calorimetry (ITC) was used to study interactions between water vapour and the surface of thermally converted sodium bicarbonate (NaHCO3). The decarboxylation degree of the samples was varied from 3% to 35% and the humidity range was 54–100%. The obtained enthalpy values were all exothermic and showed a positive linear correlation with decarboxylation degrees for each humidity studied. The critical humidity, 75% (RHo), was determined as the inflection point on a plot of the mean−ΔH kJ/mole Na2CO3 against RH. Humidities above the critical humidity lead to complete surface dissolution. The water uptake (m) was determined after each calorimetric experiment, complementing the enthalpy data. A mechanism of water vapour interaction with decarboxylated samples, including the formation of trona and Wegscheider’s salt on the bicarbonate surface is proposed for humidities below RHo. PMID:29403816

Tutorial on Quantification of Differences between Single- and Two-Component Two-Phase Flow and Heat Transfer

NASA Astrophysics Data System (ADS)

Delil, A. A. M.

2003-01-01

Single-component two-phase systems are envisaged for aerospace thermal control applications: Mechanically Pumped Loops, Vapour Pressure Driven Loops, Capillary Pumped Loops and Loop Heat Pipes. Thermal control applications are foreseen in different gravity environments: Micro-g, reduced-g for Mars or Moon bases, 1-g during terrestrial testing, and hyper-g in rotating spacecraft, during combat aircraft manoeuvres and in systems for outer planets. In the evaporator, adiabatic line and condenser sections of such single-component two-phase systems, the fluid is a mixture of the working liquid (for example ammonia, carbon dioxide, ethanol, or other refrigerants, etc.) and its saturated vapour. Results of two-phase two-component flow and heat transfer research (pertaining to liquid-gas mixtures, e.g. water/air, or argon or helium) are often applied to support research on flow and heat transfer in two-phase single-component systems. The first part of the tutorial updates the contents of two earlier tutorials, discussing various aerospace-related two-phase flow and heat transfer research. It deals with the different pressure gradient constituents of the total pressure gradient, with flow regime mapping (including evaporating and condensing flow trajectories in the flow pattern maps), with adiabatic flow and flashing, and with thermal-gravitational scaling issues. The remaining part of the tutorial qualitatively and quantitatively determines the differences between single- and two-component systems: Two systems that physically look similar and close, but in essence are fully different. It was already elucidated earlier that, though there is a certain degree of commonality, the differences will be anything but negligible, in many cases. These differences (quantified by some examples) illustrates how careful one shall be in interpreting data resulting from two-phase two-component simulations or experiments, for the development of single-component two-phase thermal control

Capillary microextraction: A new method for sampling methamphetamine vapour.

PubMed

Nair, M V; Miskelly, G M

2016-11-01

Clandestine laboratories pose a serious health risk to first responders, investigators, decontamination companies, and the public who may be inadvertently exposed to methamphetamine and other chemicals used in its manufacture. Therefore there is an urgent need for reliable methods to detect and measure methamphetamine at such sites. The most common method for determining methamphetamine contamination at former clandestine laboratory sites is selected surface wipe sampling, followed by analysis with gas chromatography-mass spectrometry (GC-MS). We are investigating the use of sampling for methamphetamine vapour to complement such wipe sampling. In this study, we report the use of capillary microextraction (CME) devices for sampling airborne methamphetamine, and compare their sampling efficiency with a previously reported dynamic SPME method. The CME devices consisted of PDMS-coated glass filter strips inside a glass tube. The devices were used to dynamically sample methamphetamine vapour in the range of 0.42-4.2μgm -3 , generated by a custom-built vapour dosing system, for 1-15min, and methamphetamine was analysed using a GC-MS fitted with a ChromatoProbe thermal desorption unit. The devices showed good reproducibility (RSD<15%), and a curvilinear pre-equilibrium relationship between sampling times and peak area, which can be utilised for calibration. Under identical sampling conditions, the CME devices were approximately 30 times more sensitive than the dynamic SPME method. The CME devices could be stored for up to 3days after sampling prior to analysis. Consecutive sampling of methamphetamine and its isotopic substitute, d-9 methamphetamine showed no competitive displacement. This suggests that CME devices, pre-loaded with an internal standard, could be a feasible method for sampling airborne methamphetamine at former clandestine laboratories. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Age-related differences in tongue-palate pressures for strength and swallowing tasks.

PubMed

Fei, Tiffany; Polacco, Rebecca Cliffe; Hori, Sarah E; Molfenter, Sonja M; Peladeau-Pigeon, Melanie; Tsang, Clemence; Steele, Catriona M

2013-12-01

The tongue plays a key role in the generation of pressures for transporting liquids and foods through the mouth in swallowing. Recent studies suggest that there is an age-related decline in tongue strength in healthy adults. However, whether age-related changes occur in tongue pressures generated for the purpose of swallowing remains unclear. Prior literature in this regard does not clearly explore the influence of task on apparent age-related differences in tongue pressure amplitudes. Furthermore, differences attributable to variations across individuals in strength, independent of age, have not clearly been elucidated. In this study, our goal was to clarify whether older adults have reduced tongue-palate pressures during maximum isometric, saliva swallowing, and water swallowing tasks, while controlling for individual variations in strength. Data were collected from 40 healthy younger adults (under age 40) and 38 healthy mature adults (over age 60). As a group, the mature participants had significantly lower maximum isometric pressures (MIPs). Swallowing pressures differed significantly by task, with higher pressures seen in saliva swallows than in water swallows. Age-group differences were not seen in swallowing pressures. Consideration of MIP as a covariate in the analysis of swallowing pressures revealed significant correlations between strength and swallowing pressures in the older participant group. Age-group differences were evident only when strength was considered in the model, suggesting that apparent age-related differences are, in fact, explained by differences in strength, which tends to be lower in healthy older adults. Our results show no evidence of independent differences in swallowing pressures attributable to age.

Energy and Exergy Analysis of Vapour Absorption Refrigeration Cycle—A Review

NASA Astrophysics Data System (ADS)

Kanabar, Bhaveshkumar Kantilal; Ramani, Bharatkumar Maganbhai

2016-07-01

In recent years, an energy crisis and the energy consumption have become global problems which restrict the sustainable growth. In these scenarios the scientific energy recovery and the utilization of various kinds of waste heat become very important. The waste heat can be utilized in many ways and one of the best practices is to use it for vapour absorption refrigeration system. To ensure efficient working of absorption cycle and utilization of optimum heat, exergy is the best tool for analysis. This paper provides the comprehensive picture of research and development of absorption refrigeration technology, practical and theoretical analysis with different arrangements of the cycle.

Venera 15: Water vapour in the middle atmosphere of Venus

NASA Astrophysics Data System (ADS)

Ignatiev, N. I.; Moroz, V. I.; Zasova, L. V.; Khatuntsev, I. V.

1999-01-01

In 1983, spectra of Venus in the region of 6-40 μm were measured by means of the Fourier Spectrometer aboard the Venera 15 orbiter. It covered local solar times from 4 a.m. to 10 a.m. and from 4 p.m. to 10 p.m. in the latitude range from -65° up to 87°. The results of an extended processing and analysis of these data are presented. Time and spatial variations of the water vapour were found. Most of the measurements fall in the range of 5-15 ppm, which is close to the early results. The effective altitude of sounding is approximately equal to the altitude where the optical depth τ = 1. Two latitude regions can be distinguished: (A) 20° < φ < 50° and (B) φ > 60°, which are characterised by different altitudes of the level of τ = 1: 62 and 55 km respectively. Mean mixing ratios near this level in the two regions are almost the same, but the partial pressures and mass densities in region (B) are 2-4 times greater than those in region (A). In region (A) a weak dayside maximum and a nightside minimum were observed. Region (B) is of inhomogeneous structure, and the retrieved mixing ratio has greater uncertainty and may probably change from the detection limit of 1 ppm up to 30 ppm. Although the retrieval of H2O mixing ratio altitude profile from the Venera 15 data appeared to be impossible, indirect indications were found that at least in region (A) the mixing ratio decreases with altitude.

Stomatal dynamics are limited by leaf hydraulics in ferns and conifers: results from simultaneous measurements of liquid and vapour fluxes in leaves.

PubMed

Martins, Samuel C V; McAdam, Scott A M; Deans, Ross M; DaMatta, Fábio M; Brodribb, Tim J

2016-03-01

Stomatal responsiveness to vapour pressure deficit (VPD) results in continuous regulation of daytime gas-exchange directly influencing leaf water status and carbon gain. Current models can reasonably predict steady-state stomatal conductance (gs ) to changes in VPD but the gs dynamics between steady-states are poorly known. Here, we used a diverse sample of conifers and ferns to show that leaf hydraulic architecture, in particular leaf capacitance, has a major role in determining the gs response time to perturbations in VPD. By using simultaneous measurements of liquid and vapour fluxes into and out of leaves, the in situ fluctuations in leaf water balance were calculated and appeared to be closely tracked by changes in gs thus supporting a passive model of stomatal control. Indeed, good agreement was found between observed and predicted gs when using a hydropassive model based on hydraulic traits. We contend that a simple passive hydraulic control of stomata in response to changes in leaf water status provides for efficient stomatal responses to VPD in ferns and conifers, leading to closure rates as fast or faster than those seen in most angiosperms. © 2015 John Wiley & Sons Ltd.

Precipitable water vapour content from ESR/SKYNET sun-sky radiometers: validation against GNSS/GPS and AERONET over three different sites in Europe

NASA Astrophysics Data System (ADS)

Campanelli, Monica; Mascitelli, Alessandra; Sanò, Paolo; Diémoz, Henri; Estellés, Victor; Federico, Stefano; Iannarelli, Anna Maria; Fratarcangeli, Francesca; Mazzoni, Augusto; Realini, Eugenio; Crespi, Mattia; Bock, Olivier; Martínez-Lozano, Jose A.; Dietrich, Stefano

2018-01-01

The estimation of the precipitable water vapour content (W) with high temporal and spatial resolution is of great interest to both meteorological and climatological studies. Several methodologies based on remote sensing techniques have been recently developed in order to obtain accurate and frequent measurements of this atmospheric parameter. Among them, the relative low cost and easy deployment of sun-sky radiometers, or sun photometers, operating in several international networks, allowed the development of automatic estimations of W from these instruments with high temporal resolution. However, the great problem of this methodology is the estimation of the sun-photometric calibration parameters. The objective of this paper is to validate a new methodology based on the hypothesis that the calibration parameters characterizing the atmospheric transmittance at 940 nm are dependent on vertical profiles of temperature, air pressure and moisture typical of each measurement site. To obtain the calibration parameters some simultaneously seasonal measurements of W, from independent sources, taken over a large range of solar zenith angle and covering a wide range of W, are needed. In this work yearly GNSS/GPS datasets were used for obtaining a table of photometric calibration constants and the methodology was applied and validated in three European ESR-SKYNET network sites, characterized by different atmospheric and climatic conditions: Rome, Valencia and Aosta. Results were validated against the GNSS/GPS and AErosol RObotic NETwork (AERONET) W estimations. In both the validations the agreement was very high, with a percentage RMSD of about 6, 13 and 8 % in the case of GPS intercomparison at Rome, Aosta and Valencia, respectively, and of 8 % in the case of AERONET comparison in Valencia. Analysing the results by W classes, the present methodology was found to clearly improve W estimation at low W content when compared against AERONET in terms of % bias, bringing the

Influence of spatial and temporal variability of subsurface soil moisture and temperature on vapour intrusion

NASA Astrophysics Data System (ADS)

Bekele, Dawit N.; Naidu, Ravi; Chadalavada, Sreenivasulu

2014-05-01

A comprehensive field study was conducted at a site contaminated with chlorinated solvents, mainly trichloroethylene (TCE), to investigate the influence of subsurface soil moisture and temperature on vapour intrusion (VI) into built structures. Existing approaches to predict the risk of VI intrusion into buildings assume homogeneous or discrete layers in the vadose zone through which TCE migrates from an underlying source zone. In reality, the subsurface of the majority of contaminated sites will be subject to significant variations in moisture and temperature. Detailed site-specific data were measured contemporaneously to evaluate the impact of spatial and temporal variability of subsurface soil properties on VI exposure assessment. The results revealed that indoor air vapour concentrations would be affected by spatial and temporal variability of subsurface soil moisture and temperature. The monthly monitoring of soil-gas concentrations over a period of one year at a depth of 3 m across the study site demonstrated significant variation in TCE vapour concentrations, which ranged from 480 to 629,308 μg/m3. Soil-gas wells at 1 m depth exhibited high seasonal variability in TCE vapour concentrations with a coefficient of variation 1.02 in comparison with values of 0.88 and 0.74 in 2 m and 3 m wells, respectively. Contour plots of the soil-gas TCE plume during wet and dry seasons showed that the plume moved across the site, hence locations of soil-gas monitoring wells for human risk assessment is a site specific decision. Subsurface soil-gas vapour plume characterisation at the study site demonstrates that assessment for VI is greatly influenced by subsurface soil properties such as temperature and moisture that fluctuate with the seasons of the year.

Water vapour condensation in a partly closed structure. Comparison between results obtained with an inside wet or dry bottom wall

NASA Astrophysics Data System (ADS)

Batina, Jean; Peyrous, René

2018-04-01

We are interested in the determination of the more significant parameters acting on the water vapour condensation in a partly closed structure, submitted to external constraints (temperature and humidity), in view to recover the generated droplets as an additional source of potable water. External temperature variations, by inducing temperature differences between outside and inside of the structure, lead to convective movements and thermal variations inside this structure. Through an orifice, these movements permit a renewing of the humid inner air and can lead to the condensation of the water vapour initially contained in the inner air volume and/or on the walls. With the above hypotheses, and by using a numerical simulation [1] based on the ambient air characteristics and a finite volumes method, it appears that condensed water quantities are mainly depending on the boundary conditions imposed. These conditions are: 1) dimensions of the structure; 2) external temperature and relative hygrometry; 3) the phase φ (T/RH) linking thermal and hydrometric conditions; 4) the air renewing and its hygrometry for each phase; and 5) for each case, the fact that the inside bottom wall can be wet or dry. The resulting condensed water vapour quantities obtained, for the width section, point out clearly that they are very depending on this phase φ (T/RH) which appears as the more significant parameter and can be modified by the presence or not of a thin layer of water vapour on the inside bottom wall. Condensation phenomenon could be increased if φ could be optimized.

Mean Blood Pressure Difference among Adolescents Based on Dyssomnia Types.

PubMed

Sembiring, Krisnarta; Ramayani, Oke Rina; Lubis, Munar

2018-02-15

Dyssomnia is the most frequent sleep disturbance and associated with increased blood pressure. There has been no study determining the difference in mean blood pressure based on dyssomnia types among adolescents. To determine the difference in mean blood pressure among adolescents based on dyssomnia types. Cross-sectional study was conducted in SMP Negeri 1 Muara Batang Gadis in April 2016. Samples were students having sleep disturbance based on Sleep Disturbance Scale for Children (SDSC) questionnaire. Stature and blood pressure data were collected along with demographic data and sleep disorder questionnaire. Analyses were done with Kruskal-Wallis test and logistic regression. P - value < 0.05 was considered significant. Seventy-six samples were obtained with mean age 13.9 (SD 1.14) years - old. Dyssomnia proportion and hypertension were 72/76 and 20/76 respectively. Mean systolic (SBP) and diastolic blood pressure (DBP) was 111.1 (SD 16.46) mmHg and 70.3 (SD 11.98) mmHg respectively. Mean SDSC score was 49.7 (SD 8.96), and the most frequent dyssomnia type was disorders of initiating and maintaining sleep. Age and sex were not the risk factors of hypertension in dyssomnia. There was a significant difference in mean SBP (P = 0.006) and DBP (P = 0.022) based on dyssomnia types. Combination dyssomnia type had the highest mean blood pressure among dyssomnia types. There is a significant difference in mean blood pressure among adolescents based on dyssomnia types.

Effect of pressure difference on the quality of titanium casting.

PubMed

Watanabe, I; Watkins, J H; Nakajima, H; Atsuta, M; Okabe, T

1997-03-01

In casting titanium using a two-compartment casting machine, Herø et al. (1993) reported that the pressure difference between the melting chamber and the mold chamber affected the soundness of the castings. This study tested the hypothesis that differences in pressure produce castings with various amounts of porosity and different mechanical properties values. Plastic dumbbell-shaped patterns were invested with an alumina-based, phosphate-bonded investment material. Both chambers of the casting machine were evacuated to 6 x 10(-2) torr; the argon pressure difference was then adjusted to either 50, 150, 300, or 450 torr. The porosity of the cast specimens was determined by x-ray radiography and quantitative image analysis. Tensile strength and elongation were measured by means of a universal testing machine at a strain rate of 1.7 x 10(-4)/s. The fractured surfaces were examined by SEM. Changes in Vickers hardness with depth from the cast surface were measured on polished cross-sections of the specimens. Raising the argon pressure difference to 300 and 450 torr caused a significant increase in internal porosity and a resultant decrease in the engineering tensile strength and elongation. The highest tensile strength (approximately 540 MPa), elongation (approximately 10%), bulk hardness (HV50g 209), and lowest porosity level (approximately 0.8%) occurred in the specimens cast at 150 torr. Turbulence of the metal during casting was thought to be responsible for the increase in porosity levels with the increase in argon pressure difference. By choosing an argon pressure difference (around 150 torr) suitable for this geometry, we could produce castings which have adequate mechanical properties and low porosity levels.

Synthesis and characterization of a mixed phase of anatase TiO2 and TiO2(B) by low pressure chemical vapour deposition (LPCVD) for high photocatalytic activity

NASA Astrophysics Data System (ADS)

Chimupala, Y.; Hyett, G.; Simpson, R.; Brydson, R.

2014-06-01

This project is concerned with enhancing photocatalytic activity by preparing a mixed phase of nano-sized TiO2. TiO2 thin films were synthesized by using Low Pressure Chemical Vapour Deposition (LPCVD). Titanium isopropoxide and N2 gas were used as the precursor and carrier gas respectively. The effects of reaction temperature, carrier gas flow rate and deposited area were studied. TiO2 thin films with nano-sized TiO2 particles were obtained under suitable conditions and SEM, TEM, powder XRD and Raman spectroscopy were employed to characterize the phase and physical appearance of synthesized materials. Preliminary results show that a dual phase (TiO2(B) and anatase) thin film nanopowder was successfully prepared by LPCVD with needle- and polygonal plate-shape crystallites respectively. This thin film deposit produced a preferred orientation of TiO2(B) needles in the [001] direction of average crystallite size 50-80 nm in length and 5-10 nm in width, whilst the crystallite size of anatase polygonal-plates was around 200 nm. The optimal LPCVD condition for preparing this mixed phase of TiO2 was 600°C with a 1 mL/s N2 flow rate.

A vapourized Δ(9)-tetrahydrocannabinol (Δ(9)-THC) delivery system part I: development and validation of a pulmonary cannabinoid route of exposure for experimental pharmacology studies in rodents.

PubMed

Manwell, Laurie A; Charchoglyan, Armen; Brewer, Dyanne; Matthews, Brittany A; Heipel, Heather; Mallet, Paul E

2014-01-01

Most studies evaluating the effects of Δ(9)-tetrahydrocannabinol (Δ(9)-THC) in animal models administer it via a parenteral route (e.g., intraperitoneal (IP) or intravenous injection (IV)), however, the common route of administration for human users is pulmonary (e.g., smoking or vapourizing marijuana). A vapourized Δ(9)-THC delivery system for rodents was developed and used to compare the effects of pulmonary and parenteral Δ(9)-THC administration on blood cannabinoid levels and behaviour. Sprague-Dawley rats were exposed to pulmonary Δ(9)-THC (1, 5, and 10mg of inhaled vapour) delivered via a Volcano® vapourizing device (Storz and Bickel, Germany) or to parenteral Δ(9)-THC (0.25, 0.5, 1.0, and 1.5mg/kg injected IP). Quantification of Δ(9)-THC and its psychoactive metabolite, 11-hydroxy-Δ(9)-THC (11-OH-Δ(9)-THC), in blood was determined by liquid chromatography/mass spectrometry (LC/MS). In order to verify the potential for the vapourization procedure to produce a robust conditioned place preference (CPP) or conditioned place avoidance CPA, classical conditioning procedures were systematically varied by altering the exposure time (10 or 20min) and number of exposed rats (1 or 2) while maintaining the same vapourization dose (10mg). Blood collected at 20min intervals showed similar dose-dependent and time-dependent changes in Δ(9)-THC and 11-OH-Δ(9)-THC for both pulmonary and parenteral administration of Δ(9)-THC. However, vapourized Δ(9)-THC induced CPP under certain conditions whereas IP-administered Δ(9)-THC induced CPA. These results support and extend the limited evidence (e.g., in humans, Naef et al., 2004; in rodents, Niyuhire et al., 2007) that Δ(9)-THC produces qualitatively different effects on behaviour depending upon the route of administration. Copyright © 2014 Elsevier Inc. All rights reserved.

Water vapour in the middle atmosphere of Venus:. An improved treatment of the Venera 15 ir spectra

NASA Astrophysics Data System (ADS)

Ignatiev, N. i.; Moroz, V. i.; Zasova, L. V.; Khatuntsev, I. v.

1999-08-01

In 1983, spectra of Venus in the region of 6-40 μm were measured by means of the Fourier Spectrometer aboard the Venera 15 orbiter. It covered local solar times from 4 am to 10 am and from 4 pm to 10 pm in the latitude range from 65°S up to 87°N. The results of an extended processing and analysis of these data are presented. Time and spatial variations of the water vapour were found. Most of the measurements fall in the range of 5-15 ppm, which is close to earlier results. The effective altitude of sounding is approximately equal to the altitude where the optical depth τ = 1. In the northern hemisphere, which was mainly covered by the measurements, two latitude regions can be distinguished; (A) 20° < φ < 50° and (B) φ > 60°, which are characterised by different altitudes of the level of τ = 1, 62 and 55 km respectively. Mean mixing ratios near this level in the two regions are almost the same, but the partial pressures and mass densities in the region (B) are 2-4 times greater than those in region (A). In region (A) a weak maximum was detected near 10 am local solar time (17 ppm at φ = 35°) and a minimum-near 10 pm (2ppm at φ = 30°). Region (B) is of inhomogeneous structure, and the retrieved mixing ratio has greater uncertainty and may probably change from the low values up to 30 ppm. In region (A) the water vapour mass density at the level of τ = 1 is 2-4 times greater than the mean density of the water contained in aerosol particles, while in region (B) this ratio may vary in the limits 0.5-5. Although the retrieval of H2O mixing ratio altitude profile from the Venera 15 data appeared to be impossible, indirect indications were found that at least in region (A) the mixing ratio decreases with altitude.

Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS) through laboratory studies of inorganic species

DOE PAGES

Hu, Weiwei; Campuzano-Jost, Pedro; Day, Douglas A.; ...

2017-08-15

Aerosol mass spectrometers (AMSs) and Aerosol Chemical Speciation Monitors (ACSMs) commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV) that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE) to correct for the loss of particles due to bounce. A new capture vapourizer (CV) has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in themore » laboratory. Four standard species, NH 4NO 3, NaNO 3, (NH 4) 2SO 4 and NH 4Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature ( T v ∼ 200–800 °C) on the detected fragments, CE and size distributions are investigated. A T v of 500–550 °C for the CV is recommended. In the CV, CE was identical (around unity) for more volatile species (e.g. NH 4NO 3) and comparable to or higher than the SV for less-volatile species (e.g. (NH 4) 2SO 4), demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO 3 and SO 4 species observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO 2(g) from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH 4NO 3 and comparable to the SV for NaNO 3. . We observe an extremely consistent fragmentation for

Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS) through laboratory studies of inorganic species

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

Hu, Weiwei; Campuzano-Jost, Pedro; Day, Douglas A.

Aerosol mass spectrometers (AMSs) and Aerosol Chemical Speciation Monitors (ACSMs) commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV) that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE) to correct for the loss of particles due to bounce. A new capture vapourizer (CV) has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in themore » laboratory. Four standard species, NH 4NO 3, NaNO 3, (NH 4) 2SO 4 and NH 4Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature ( T v ∼ 200–800 °C) on the detected fragments, CE and size distributions are investigated. A T v of 500–550 °C for the CV is recommended. In the CV, CE was identical (around unity) for more volatile species (e.g. NH 4NO 3) and comparable to or higher than the SV for less-volatile species (e.g. (NH 4) 2SO 4), demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO 3 and SO 4 species observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO 2(g) from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH 4NO 3 and comparable to the SV for NaNO 3. . We observe an extremely consistent fragmentation for

Does the Position or Contact Pressure of the Stethoscope Make Any Difference to Clinical Blood Pressure Measurements

PubMed Central

Pan, Fan; Zheng, Dingchang; He, Peiyu; Murray, Alan

2014-01-01

Abstract This study aimed to investigate the effect of stethoscope position and contact pressure on auscultatory blood pressure (BP) measurement. Thirty healthy subjects were studied. Two identical stethoscopes (one under the cuff, the other outside the cuff) were used to simultaneously and digitally record 2 channels of Korotkoff sounds during linear cuff pressure deflation. For each subject, 3 measurements with different contact pressures (0, 50, and 100 mm Hg) on the stethoscope outside the cuff were each recorded at 3 repeat sessions. The Korotkoff sounds were replayed twice on separate days to each of 2 experienced listeners to determine systolic and diastolic BPs (SBP and DBP). Variance analysis was performed to study the measurement repeatability and the effect of stethoscope position and contact pressure on BPs. There was no significant BP difference between the 3 repeat sessions, between the 2 determinations from each listener, between the 2 listeners and between the 3 stethoscope contact pressures (all P > 0.06). There was no significant SBP difference between the 2 stethoscope positions at the 2 lower stethoscope pressures (P = 0.23 and 0.45), but there was a small (0.4 mm Hg, clinically unimportant) significant difference (P = 0.005) at the highest stethoscope pressure. The key result was that, DBP from the stethoscope under the cuff was significantly lower than that from outside the cuff by 2.8 mm Hg (P < 0.001, 95% confidence interval −3.5 to −2.1 mm Hg). Since it is known that the traditional Korotkoff sound method, with the stethoscope outside the cuff, tends to give a higher DBP than the true intra-arterial pressure, this study could suggest that the stethoscope position under the cuff, and closer to the arterial occlusion, might yield measurements closer to the actual invasive DBP. PMID:25546675

Application of lemongrass oil in vapour phase for the effective control of anthracnose of 'Sekaki' papaya.

PubMed

Ali, A; Wee Pheng, T; Mustafa, M A

2015-06-01

To evaluate the potential use of lemongrass essential oil vapour as an alternative for synthetic fungicides in controlling anthracnose of papaya. Lemongrass oil used in the study was characterized using gas chromatography-flame ionization detection (GC-FID) before it was tested against anthracnose of papaya in vitro and in vivo. The GC-FID analysis showed that geranial (45·6%) and neral (34·3%) were the major components in lemongrass oil. In vitro study revealed that lemongrass oil vapour at all concentrations tested (33, 66, 132, 264 and 528 μl l(-1) ) suppressed the mycelial growth and conidial germination of Colletotrichum gloeosporioides. For the in vivo study, 'Sekaki' papaya were exposed to lemongrass oil fumigation (0, 7, 14, 28 μl l(-1) ) for 18 h and at room temperature for 9 days. Lemongrass oil vapour at the concentration of 28 μl l(-1) was most effective against anthracnose of artificially inoculated papaya fruit while quality parameters of papaya were not significantly altered. This suggests that lemongrass oil vapour can control anthracnose disease development on papaya without affecting its natural ripening process. The potential practical application of this technology can reduce reliance on synthetic fungicides for the control of postharvest diseases in papaya. © 2015 The Society for Applied Microbiology.

Retrievability of atmospheric water vapour, temperature and vertical windspeed profiles from proposed sub-millimetre instrument ORTIS.

NASA Astrophysics Data System (ADS)

Hurley, Jane; Irwin, Patrick; Teanby, Nicholas; de Kok, Remco; Calcutt, Simon; Irshad, Ranah; Ellison, Brian

2010-05-01

The sub-millimetre range of the spectrum has been exploited in the field of Earth observation by many instruments over the years and has provided a plethora of information on atmospheric chemistry and dynamics - however, this spectral range has not been fully explored in planetary science. To this end, a sub-millimetre instrument, the Orbiter Terahertz Infrared Spectrometer (ORTIS), is jointly proposed by the University of Oxford and the Rutherford Appleton Laboratory, to meet the requirements of the European Space Agency's Cosmic Visions Europa Jupiter System Mission (EJSM). ORTIS will consist of an infrared and a sub-millimetre component; however in this study only the sub-millimetre component will be explored. The sub-millimetre component of ORTIS is projected to measure a narrow band of frequencies centred at approximately 2.2 THz, with a spectral resolution varying between approximately 1 kHz and 1 MHz, and having an expected noise magnitude of 2 nW/cm2 sr cm-1. In this spectral region, there are strong water and methane emission lines at most altitudes on Jupiter. The sub-millimetre component of ORTIS is designed to measure the abundance of atmospheric water vapour and atmospheric temperature, as well as vertical windspeed profiles from Doppler-shifted emission lines, measured at high spectral resolution. This study will test to see if, in practice, these science objectives may be met from the planned design, as applied to Jupiter. In order to test the retrievability of atmospheric water vapour, temperature and windspeed with the proposed ORTIS design, it is necessary to have a set of "measurements' for which the input parameters (such as species' concentrations, atmospheric temperature, pressure - and windspeed) are known. This is accomplished by generating a set of radiative transfer simulations using radiative transfer model RadTrans in the spectral range sampled by ORTIS, whereby the atmospheric data pertaining to Jupiter have provided by Cassini

A surface curvature oscillation model for vapour-liquid-solid growth of periodic one-dimensional nanostructures

NASA Astrophysics Data System (ADS)

Wang, Hui; Wang, Jian-Tao; Cao, Ze-Xian; Zhang, Wen-Jun; Lee, Chun-Sing; Lee, Shuit-Tong; Zhang, Xiao-Hong

2015-03-01

While the vapour-liquid-solid process has been widely used for growing one-dimensional nanostructures, quantitative understanding of the process is still far from adequate. For example, the origins for the growth of periodic one-dimensional nanostructures are not fully understood. Here we observe that morphologies in a wide range of periodic one-dimensional nanostructures can be described by two quantitative relationships: first, inverse of the periodic spacing along the length direction follows an arithmetic sequence; second, the periodic spacing in the growth direction varies linearly with the diameter of the nanostructure. We further find that these geometric relationships can be explained by considering the surface curvature oscillation of the liquid sphere at the tip of the growing nanostructure. The work reveals the requirements of vapour-liquid-solid growth. It can be applied for quantitative understanding of vapour-liquid-solid growth and to design experiments for controlled growth of nanostructures with custom-designed morphologies.

Prediction of clothing thermal insulation and moisture vapour resistance of the clothed body walking in wind.

PubMed

Qian, Xiaoming; Fan, Jintu

2006-11-01

Clothing thermal insulation and moisture vapour resistance are the two most important parameters in thermal environmental engineering, functional clothing design and end use of clothing ensembles. In this study, clothing thermal insulation and moisture vapour resistance of various types of clothing ensembles were measured using the walking-able sweating manikin, Walter, under various environmental conditions and walking speeds. Based on an extensive experimental investigation and an improved understanding of the effects of body activities and environmental conditions, a simple but effective direct regression model has been established, for predicting the clothing thermal insulation and moisture vapour resistance under wind and walking motion, from those when the manikin was standing in still air. The model has been validated by using experimental data reported in the previous literature. It has shown that the new models have advantages and provide very accurate prediction.

Oscillometric blood pressure devices and simulators: measurements of repeatability and differences between models.

PubMed

Sims, A J; Reay, C A; Bousfield, D R; Menes, J A; Murray, A

2005-01-01

To measure the repeatability and pressure pulse envelope of simulators used for testing oscillometric non-invasive blood pressure (NIBP) devices; to study the effect of different envelopes on NIBP devices, and to measure the difference between NIBP devices due to different oscillometric algorithms. Three different models of NIBP simulator and 18 different patient monitors with NIBP function were studied. We developed a pressure measurement system (accuracy 0.048?mmHg) to measure the repeatability of simulators. The effect of changing the envelope was measured by using three simulators with one NIBP device. Differences between 18 NIBP devices were measured using one simulator at seven blood pressure settings. Simulators generate repeatable pressure pulse envelopes (< 0.2 mmHg) but the magnitude and shape depends on the model of simulator. Oscillometric NIBP devices are highly repeatable (< 2 mmHg) when presented with a repeatable pressure pulse envelope, but different devices employ different algorithms and give different results. For a simulated standard blood pressure setting of 120/80 mmHg, estimates of systolic pressure ranged from 112.6 to 126.6 mmHg (sd of 3.0 mmHg), and diastolic pressure ranged from 74.8 to 86.9 mmHg (sd of 3.5 mmHg). Simulators and NIBP devices are sufficiently repeatable for clinical use, but further systematic clinical studies are required to better characterize the pressure pulse envelope for different patient groups.

Analysing the mechanisms of soil water and vapour transport in the desert vadose zone of the extremely arid region of northern China

NASA Astrophysics Data System (ADS)

Du, Chaoyang; Yu, Jingjie; Wang, Ping; Zhang, Yichi

2018-03-01

The transport of water and vapour in the desert vadose zone plays a critical role in the overall water and energy balances of near-surface environments in arid regions. However, field measurements in extremely dry environments face many difficulties and challenges, so few studies have examined water and vapour transport processes in the desert vadose zone. The main objective of this study is to analyse the mechanisms of soil water and vapour transport in the desert vadose zone (depth of ∼350 cm) by using measured and modelled data in an extremely arid environment. The field experiments are implemented in an area of the Gobi desert in northwestern China to measure the soil properties, daily soil moisture and temperature, daily water-table depth and temperature, and daily meteorological records from DOYs (Days of Year) 114-212 in 2014 (growing season). The Hydrus-1D model, which simulates the coupled transport of water, vapour and heat in the vadose zone, is employed to simulate the layered soil moisture and temperature regimes and analyse the transport processes of soil water and vapour. The measured results show that the soil water and temperatures near the land surface have visible daily fluctuations across the entire soil profile. Thermal vapour movement is the most important component of the total water flux and the soil temperature gradient is the major driving factor that affects vapour transport in the desert vadose zone. The most active water and heat exchange occurs in the upper soil layer (depths of 0-25 cm). The matric potential change from the precipitation mainly re-draws the spatio-temporal distribution of the isothermal liquid water in the soil near the land surface. The matric potential has little effect on the isothermal vapour and thermal liquid water flux. These findings offer new insights into the liquid water and vapour movement processes in the extremely arid environment.

Synthesis, structure, vapour pressure and deposition of ZnO thin film by plasma assisted MOCVD technique using a novel precursor bis[(pentylnitrilomethylidine) (pentylnitrilomethylidine-μ-phenalato)]dizinc(II)

NASA Astrophysics Data System (ADS)

Chandrakala, C.; Sravanthi, P.; Raj Bharath, S.; Arockiasamy, S.; George Johnson, M.; Nagaraja, K. S.; Jeyaraj, B.

2017-02-01

A novel binuclear zinc schiff's base complex bis[(pentylnitrilomethylidine)(pentylnitrilomethylidine-μ-phenalato)]dizinc(II) (hereafter referred as ZSP) was prepared and used as a precursor for the deposition of ZnO thin film by MOCVD. The dynamic TG run of ZSP showed sufficient volatility and good thermal stability. The temperature dependence of vapour pressure measured by transpiration technique yielded a value of 55.8 ± 2.3 kJ mol-1 for the enthalpy of sublimation (ΔH°sub) in the temperature range of 423-503 K. The crystal structure of ZSP was solved by single crystal XRD which exhibits triclinic crystal system with the space group of Pī. The molecular mass of ZSP was determined by mass spectrometry which yielded the m/z value of 891 and 445 Da corresponding to its dimeric as well as monomeric form. The complex ZSP was further characterized by FT-IR and NMR. The demonstration of ZnO thin film deposition was carried out by using plasma assisted MOCVD. The thin film XRD confirmed the highly oriented (002) ZnO thin films on Si(100) substrate. The uniformity and composition of the thin film were analyzed by SEM/EDX. The band gap of ZnO thin film measurement indicated the blue shift with the value of 3.79 eV.

High-spatial-resolution mapping of precipitable water vapour using SAR interferograms, GPS observations and ERA-Interim reanalysis

NASA Astrophysics Data System (ADS)

Tang, Wei; Liao, Mingsheng; Zhang, Lu; Li, Wei; Yu, Weimin

2016-09-01

A high spatial and temporal resolution of the precipitable water vapour (PWV) in the atmosphere is a key requirement for the short-scale weather forecasting and climate research. The aim of this work is to derive temporally differenced maps of the spatial distribution of PWV by analysing the tropospheric delay "noise" in interferometric synthetic aperture radar (InSAR). Time series maps of differential PWV were obtained by processing a set of ENVISAT ASAR (Advanced Synthetic Aperture Radar) images covering the area of southern California, USA from 6 October 2007 to 29 November 2008. To get a more accurate PWV, the component of hydrostatic delay was calculated and subtracted by using ERA-Interim reanalysis products. In addition, the ERA-Interim was used to compute the conversion factors required to convert the zenith wet delay to water vapour. The InSAR-derived differential PWV maps were calibrated by means of the GPS PWV measurements over the study area. We validated our results against the measurements of PWV derived from the Medium Resolution Imaging Spectrometer (MERIS) which was located together with the ASAR sensor on board the ENVISAT satellite. Our comparative results show strong spatial correlations between the two data sets. The difference maps have Gaussian distributions with mean values close to zero and standard deviations below 2 mm. The advantage of the InSAR technique is that it provides water vapour distribution with a spatial resolution as fine as 20 m and an accuracy of ˜ 2 mm. Such high-spatial-resolution maps of PWV could lead to much greater accuracy in meteorological understanding and quantitative precipitation forecasts. With the launch of Sentinel-1A and Sentinel-1B satellites, every few days (6 days) new SAR images can be acquired with a wide swath up to 250 km, enabling a unique operational service for InSAR-based water vapour maps with unprecedented spatial and temporal resolution.

CFD simulation of water vapour condensation in the presence of non-condensable gas in vertical cylindrical condensers.

PubMed

Li, Jun-De

2013-02-01

This paper presents the simulation of the condensation of water vapour in the presence of non-condensable gas using computational fluid dynamics (CFD) for turbulent flows in a vertical cylindrical condenser tube. The simulation accounts for the turbulent flow of the gas mixture, the condenser wall and the turbulent flow of the coolant in the annular channel with no assumptions of constant wall temperature or heat flux. The condensate film is assumed to occupy a negligible volume and its effect on the condensation of the water vapour has been taken into account by imposing a set of boundary conditions. A new strategy is used to overcome the limitation of the currently available commercial CFD package to solve the simultaneous simulation of flows involving multispecies and fluids of gas and liquid in separate channels. The results from the CFD simulations are compared with the experimental results from the literature for the condensation of water vapour with air as the non-condensable gas and for inlet mass fraction of the water vapour from 0.66 to 0.98. The CFD simulation results in general agree well with the directly measured quantities and it is found that the variation of heat flux in the condenser tube is more complex than a simple polynomial curve fit. The CFD results also show that, at least for flows involving high water vapour content, the axial velocity of the gas mixture at the interface between the gas mixture and the condensate film is in general not small and cannot be neglected.

CFD simulation of water vapour condensation in the presence of non-condensable gas in vertical cylindrical condensers

PubMed Central

Li, Jun-De

2013-01-01

This paper presents the simulation of the condensation of water vapour in the presence of non-condensable gas using computational fluid dynamics (CFD) for turbulent flows in a vertical cylindrical condenser tube. The simulation accounts for the turbulent flow of the gas mixture, the condenser wall and the turbulent flow of the coolant in the annular channel with no assumptions of constant wall temperature or heat flux. The condensate film is assumed to occupy a negligible volume and its effect on the condensation of the water vapour has been taken into account by imposing a set of boundary conditions. A new strategy is used to overcome the limitation of the currently available commercial CFD package to solve the simultaneous simulation of flows involving multispecies and fluids of gas and liquid in separate channels. The results from the CFD simulations are compared with the experimental results from the literature for the condensation of water vapour with air as the non-condensable gas and for inlet mass fraction of the water vapour from 0.66 to 0.98. The CFD simulation results in general agree well with the directly measured quantities and it is found that the variation of heat flux in the condenser tube is more complex than a simple polynomial curve fit. The CFD results also show that, at least for flows involving high water vapour content, the axial velocity of the gas mixture at the interface between the gas mixture and the condensate film is in general not small and cannot be neglected. PMID:24850953

In situ measurement of CO2 and water vapour isotopic compositions at a forest site using mid-infrared laser absorption spectroscopy.

PubMed

Wada, Ryuichi; Matsumi, Yutaka; Takanashi, Satoru; Nakai, Yuichiro; Nakayama, Tomoki; Ouchi, Mai; Hiyama, Tetsuya; Fujiyoshi, Yasushi; Nakano, Takashi; Kurita, Naoyuki; Muramoto, Kenichiro; Kodama, Naomi

2016-12-01

We conducted continuous, high time-resolution measurements of CO2 and water vapour isotopologues ((16)O(12)C(16)O, (16)O(13)C(16)O and (18)O(12)C(16)O for CO2, and H2(18)O for water vapour) in a red pine forest at the foot of Mt. Fuji for 9 days from the end of July 2010 using in situ absorption laser spectroscopy. The δ(18)O values in water vapour were estimated using the δ(2)H-δ(18)O relationship. At a scale of several days, the temporal variations in δ(18)O-CO2 and δ(18)O-H2O are similar. The orders of the daily Keeling plots are almost identical. A possible reason for the similar behaviour of δ(18)O-CO2 and δ(18)O-H2O is considered to be that the air masses with different water vapour isotopic ratios moved into the forest, and changed the atmosphere of the forest. A significant correlation was observed between δ(18)O-CO2 and δ(13)C-CO2 values at nighttime (r(2)≈0.9) due to mixing between soil (and/or leaf) respiration and tropospheric CO2. The ratios of the discrimination coefficients (Δa/Δ) for oxygen (Δa) and carbon (Δ) isotopes during photosynthesis were estimated in the range of 0.7-1.2 from the daytime correlations between δ(18)O-CO2 and δ(13)C-CO2 values.

Lower limb intracast pressures generated by different types of immobilisation casts.

PubMed

Chaudhury, Salma; Hazlerigg, Alexandra; Vusirikala, Anuhya; Nguyen, Joseph; Matthews, Stuart

2017-02-18

To determine if complete, split casts and backslabs [plaster of Paris (POP) and fiberglass] generate different intracast pressures and pain. Increased swelling within casts was modeled by a closed water system attached to an expandable bag placed directly under different types of casts applied to a healthy lower limb. Complete fiberglass and POP casts, split casts and backslabs were applied. Twenty-five milliliter aliquots of saline were injected into the system and the generated intracast pressures were measured using a sphygmomanometer. The subject was blinded to the pressure scores to avoid bias. All casts were applied to the same right limb on the same subject to avoid the effects of variations in anatomy or physiology on intracast pressures. Pain levels were evaluated using the Visual Analogue Score after each sequential saline injection. Each type of cast was reapplied four times and the measurements were repeated on four separate occasions. Sample sizes were determined by a pre-study 90% power calculation to detect a 20% difference in intracast pressures between cast groups. A significant difference between the various types of casts was noted when the saline volume was greater than 100 mL ( P = 0.009). The greatest intracast pressure was generated by complete fiberglass casts, which were significantly higher than complete POP casts or backslabs ( P = 0.018 and P = 0.008 respectively) at intracast saline volumes of 100 mL and higher. Backslabs produced a significantly lower intracast pressure compared to complete POP only once the saline volume within casts exceeded 225 mL ( P = 0.009). Intracast pressures were significantly lower in split casts ( P = 0.003). Split POP and fiberglass casts produced the lowest intracast pressures, even compared to backslabs ( P = 0.009). Complete fiberglass casts generated the highest pain levels at manometer pressures of 75 mmHg and greater ( P = 0.001). Split fiberglass casts had significantly reduced pain levels ( P = 0

Measurements and calculations of H2-broadening and shift parameters of water vapour transitions of the ν1 + ν2 + ν3 band

NASA Astrophysics Data System (ADS)

Petrova, T. M.; Solodov, A. M.; Solodov, A. A.; Deichuli, V. M.; Starikov, V. I.

2018-05-01

The water vapour line broadening and shifting for 97 lines in the ν1 + ν2 + ν3 band induced by hydrogen pressure are measured with Bruker IFS 125 HR FTIR spectrometer. The measurements were performed at room temperature, at the spectral resolution of 0.01 cm-1 and in a wide pressure range of H2. The calculations of the broadening γ and shift δ coefficients were performed in the semi-classical method framework with use of an effective vibrationally depended interaction potential. Two potential parameters were optimised to improve the quality of calculations. Good agreements with measured broadening coefficients were achieved. The comparison of calculated broadening coefficients γ with the previous measurements is discussed. The analytical expressions that reproduce these coefficients for rotational, ν2, ν1, and ν3 vibrational bands are presented.

Efficient quantification of water content in edible oils by headspace gas chromatography with vapour phase calibration.

PubMed

Xie, Wei-Qi; Gong, Yi-Xian; Yu, Kong-Xian

2018-06-01

An automated and accurate headspace gas chromatographic (HS-GC) technique was investigated for rapidly quantifying water content in edible oils. In this method, multiple headspace extraction (MHE) procedures were used to analyse the integrated water content from the edible oil sample. A simple vapour phase calibration technique with an external vapour standard was used to calibrate both the water content in the gas phase and the total weight of water in edible oil sample. After that the water in edible oils can be quantified. The data showed that the relative standard deviation of the present HS-GC method in the precision test was less than 1.13%, the relative differences between the new method and a reference method (i.e. the oven-drying method) were no more than 1.62%. The present HS-GC method is automated, accurate, efficient, and can be a reliable tool for quantifying water content in edible oil related products and research. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Analysis of particle and vapour phase PAHs from the personal air samples of bus garage workers exposed to diesel exhaust.

PubMed

Kuusimaki, Leea; Peltonen, Kimmo; Mutanen, Pertti; Savela, Kirsti

2003-07-01

The levels of particle and vapour phase polycyclic aromatic hydrocarbons (PAHs) derived from the diesel exhaust compounds in bus garage work were measured in winter and in summer. Five personal air samples were collected from the breathing zones of 22 garage workers every other day of consecutive weeks. Control samples (n = 22) were collected from office workers in Helsinki. Fifteen PAHs in the air samples were analysed by HPLC using a fluorescence detector. Statistically significant differences were observed between total PAH levels of the exposed workers (2241 and 1245 ng/m(3)) and the control group (254 and 275 ng/m(3)) in both winter (P < 0.001) and summer (P < 0.001). Phenanthrene, pyrene, benzo[ghi]perylene and fluoranthene were the major compounds in the particle phase, and naphthalene, phenanthrene and fluorene in the vapour phase. About 98% of PAHs measured were related to the vapour phase compounds, whereas the high molecular weight PAH compounds were detected only in the particle phase. The PAH levels in the garages were twice as high (P < 0.001) in winter as in summer. Even though the exposure levels were low in the bus garages, the low level does not allow conclusions to be drawn about the possible adverse health effects due to exposure to diesel exhaust.

Evaluation of the impact of atmospheric pressure in different seasons on blood pressure in patients with arterial hypertension.

PubMed

Kamiński, Marek; Cieślik-Guerra, Urszula I; Kotas, Rafał; Mazur, Piotr; Marańda, Witold; Piotrowicz, Maciej; Sakowicz, Bartosz; Napieralski, Andrzej; Trzos, Ewa; Uznańska-Loch, Barbara; Rechciński, Tomasz; Kurpesa, Małgorzata

2016-01-01

Atmospheric pressure is the most objective weather factor because regardless of if outdoors or indoors it affects all objects in the same way. The majority of previous studies have used the average daily values of atmospheric pressure in a bioclimatic analysis and have found no correlation with blood pressure changes. The main objective of our research was to assess the relationship between atmospheric pressure recorded with a frequency of 1 measurement per minute and the results of 24-h blood pressure monitoring in patients with treated hypertension in different seasons in the moderate climate of the City of Łódź (Poland). The study group consisted of 1662 patients, divided into 2 equal groups (due to a lower and higher average value of atmospheric pressure). Comparisons between blood pressure values in the 2 groups were performed using the Mann-Whitney U test. We observed a significant difference in blood pressure recorded during the lower and higher range of atmospheric pressure: on the days of the spring months systolic (p = 0.043) and diastolic (p = 0.005) blood pressure, and at nights of the winter months systolic blood pressure (p = 0.013). A significant inverse relationship between atmospheric pressure and blood pressure during the spring days and, only for systolic blood pressure, during winter nights was observed. Int J Occup Med Environ Health 2016;29(5):783-792. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Volatile times for the very first ionic liquid: understanding the vapor pressures and enthalpies of vaporization of ethylammonium nitrate.

PubMed

Emel'yanenko, Vladimir N; Boeck, Gisela; Verevkin, Sergey P; Ludwig, Ralf

2014-09-08

A hundred years ago, Paul Walden studied ethyl ammonium nitrate (EAN), which became the first widely known ionic liquid. Although EAN has been investigated extensively, some important issues still have not been addressed; they are now tackled in this communication. By combining experimental thermogravimetric analysis with time of flight mass spectrometry (TGA-ToF-MS) and transpiration method with theoretical methods, we clarify the volatilisation of EAN from ambient to elevated temperatures. It was observed that up to 419 K, EAN evaporates as contact-ion pairs leading to very low vapour pressures of a few Pascal. Starting from 419 K, the decomposition to nitric acid and ethylamine becomes more thermodynamically favourable than proton transfer. This finding was supported by DFT calculations, which provide the free energies of all possible gas-phase species, and show that neutral molecules dominate over ion pairs above 500 K, an observation that is in nearly prefect agreement with the experimental boiling point of 513 K. This result is crucial for the ongoing practical applications of protic ionic liquids such as electrolytes for batteries and fuel cells because, in contrast to high-boiling conventional solvents, EAN exhibits no significant vapour pressure below 419 K and this property fulfils the requirements for the thermal behaviour of safe electrolytes. Overall, EAN shows the same barely measurable vapour pressures as typical aprotic ionic liquids at temperatures only 70 K lower. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microwave measurements of the absolute values of absorption by water vapour in the atmosphere.

PubMed

Hogg, D C; Guiraud, F O

1979-05-31

MEASUREMENT of the absolute value of absorption by water vapour at microwave frequencies is difficult because the effect is so small. Far in the wings of the absorption lines, in the so-called 'windows' of the spectrum, it is especially difficult to achieve high accuracy in the free atmosphere. But it is in these windows that the behaviour of the absorption is important from both applied and scientific points of view. Satellite communications, remote sensing of the atmosphere, and radioastronomy, are all influenced by this behaviour. Measurements on an Earth-space path are reported here; the results indicate a nonlinear relationship between absorption and water-vapour content.

Pressure resistance of copper benzene-1,3,5-tricarboxylate - carbon aerogel composites

NASA Astrophysics Data System (ADS)

Domán, Andrea; Nagy, Balázs; Nichele, Laura P.; Srankó, Dávid; Madarász, János; László, Krisztina

2018-03-01

The protective effect of a resorcinol - formaldehyde based carbon aerogel (CA) support was compared in two different forms of the hybrid made of copper benzene-1,3,5-tricarboxilate (HKUST-1) and CA. HKUST-1:CA with identical mass ratio (1:1). HKUST-1+CAis a physical mixture while in HKUST-1@CA the metal organic framework (MOF) crystals were grown on CA under solvothermal conditions. The effect of water vapour and the external pressure (25-200 bar) was investigated. TG/DTG data show that the prehistory of the samples has a strong influence on their thermal behaviour and nitrogen data suggest that part of the MOF grows in the wider pores of the HKUST-1@CA sample. Although there are no dramatic differences in the water adsorption isotherms, the physical mixture is slightly more proficient. In dry samples under compression the crystalline structure of the free HKUST-1 is well conserved. The nanoscale structure of the hybrids is sensitive to applied pressure and formation of mesopores of wide size distribution occurs. No significant difference was found between the corresponding CH4 adsorption isotherms of the composite samples, either in the as-prepared samples or after compression at 100 bar. After being exposed to high external pressure the CH4 uptake seems to be governed by the MOF.

Substrate patterning with NiOx nanoparticles and hot-wire chemical vapour deposition of WO3x and carbon nanostructures

NASA Astrophysics Data System (ADS)

Houweling, Z. S.

2011-10-01

The first part of the thesis treats the formation of nickel catalyst nanoparticles. First, a patterning technique using colloids is employed to create ordered distributions of monodisperse nanoparticles. Second, nickel films are thermally dewetted, which produces mobile species that self-arrange in non-ordered distributions of polydisperse particles. Third, the mobility of the nickel species is successfully reduced by the addition of air during the dewetting and the use of a special anchoring layer. Thus, non-ordered distributions of self-arranged monodisperse nickel oxide nanoparticles (82±10 nm x 16±2 nm) are made. Studies on nickel thickness, dewetting time and dewetting temperature are conducted. With these particle templates, graphitic carbon nanotubes are synthesised using catalytic hot-wire chemical vapour deposition (HWCVD), demonstrating the high-temperature processability of the nanoparticles. The second part of this thesis treats the non-catalytic HWCVD of tungsten oxides (WO3-x). Resistively heated tungsten filaments exposed to an air flow at subatmospheric pressures, produce tungsten oxide vapour species, which are collected on substrates and are subsequently characterised. First, a complete study on the process conditions is conducted, whereby the effects of filament radiation, filament temperature, process gas pressure and substrate temperature, are investigated. The thus controlled growth of nanogranular smooth amorphous and crystalline WO3-x thin films is presented for the first time. Partially crystalline smooth hydrous WO3-x thin films consisting of 20 nm grains can be deposited at very high rates. The synthesis of ultrafine powders with particle sizes of about 7 nm and very high specific surface areas of 121.7±0.4 m2·g-1 at ultrahigh deposition rates of 36 µm·min-1, is presented. Using substrate heating to 600°C or more, while using air pressures of 3·10-5 mbar to 0.1 mbar, leads to pronounced crystal structures, from nanowires, to

Development of a test method for distillation of diesel-biodiesel-alcohols mixtures at reduced pressure

NASA Astrophysics Data System (ADS)

Niculescu, R.; Iosub, I.; Clenci, A.; Zaharia, C.; Iorga-Simăn, V.

2017-10-01

Increased environmental awareness and depletion of fossil petroleum resources are driving the automotive industry to seek out and use alternative fuels. For instance, the biofuel is a major renewable energy source to supplement declining fossil fuel resources. The addition of alcohols like methanol and ethanol is practical in biodiesel blends due to its miscibility with the pure biodiesel. Alcohols also improve physico-chemical properties of biodiesel blends, which lead to improved combustion efficiency. Proper volatility of fuels is critical to the operation of internal combustion engines with respect to both performance and emissions. Volatility may be characterised by various measurements, the most common of which are vapour pressure, distillation and the vapour/liquid ratio. The presence of ethanol or other oxygenates may affect these properties and, as a result, performance and emissions, as well. However, in the case of diesel-biodiesel-alcohols mixtures, the variance of component volatility makes difficult the analysis of the overall volatility. Thus, the paper presents an experimental method of distilling diesel-biodiesel-alcohols mixtures by adjusting the boiler pressure of an i-Fischer Dist equipment.

Water vapour emission in vegetable fuel: absorption cell measurements and detection limits of our CO II Dial system

NASA Astrophysics Data System (ADS)

Bellecci, C.; De Leo, L.; Gaudio, P.; Gelfusa, M.; Lo Feudo, T.; Martellucci, S.; Richetta, M.

2006-09-01

Forest fires can be the cause of serious environmental and economic damages. For this reason a considerable effort has been directed toward the forest protection and fire fighting. In the early forest fire detection, Lidar technique present considerable advantages compared to the passive detection methods based on infrared cameras currently in common use, due its higher sensitivity and ability to accurately locate the fire. The combustion phase of the vegetable matter causes a great amount of water vapour emission, thus the water molecule behaviour will be studied to obtain a fire detection system ready and efficient also before the flame propagation. A first evaluation of increment of the water vapour concentration compared to standard one will be estimated by a numerical simulation. These results will be compared with the experimental measurements carried out into a cell with a CO II Dial system, burning different kinds of vegetable fuel. Our results and their comparison will be reported in this paper.

Giant spin Hall effect in graphene grown by chemical vapour deposition

NASA Astrophysics Data System (ADS)

Balakrishnan, Jayakumar; Koon, Gavin Kok Wai; Avsar, Ahmet; Ho, Yuda; Lee, Jong Hak; Jaiswal, Manu; Baeck, Seung-Jae; Ahn, Jong-Hyun; Ferreira, Aires; Cazalilla, Miguel A.; Neto, Antonio H. Castro; Özyilmaz, Barbaros

2014-09-01

Advances in large-area graphene synthesis via chemical vapour deposition on metals like copper were instrumental in the demonstration of graphene-based novel, wafer-scale electronic circuits and proof-of-concept applications such as flexible touch panels. Here, we show that graphene grown by chemical vapour deposition on copper is equally promising for spintronics applications. In contrast to natural graphene, our experiments demonstrate that chemically synthesized graphene has a strong spin-orbit coupling as high as 20 meV giving rise to a giant spin Hall effect. The exceptionally large spin Hall angle ~0.2 provides an important step towards graphene-based spintronics devices within existing complementary metal-oxide-semiconductor technology. Our microscopic model shows that unavoidable residual copper adatom clusters act as local spin-orbit scatterers and, in the resonant scattering limit, induce transverse spin currents with enhanced skew-scattering contribution. Our findings are confirmed independently by introducing metallic adatoms-copper, silver and gold on exfoliated graphene samples.

Partitioning understory evapotranspiration in semi-arid ecosystems in Namibia using the isotopic composition of water vapour

NASA Astrophysics Data System (ADS)

de Blécourt, Marleen; Gaj, Marcel; Holtorf, Kim-Kirsten; Gröngröft, Alexander; Brokate, Ralph; Himmelsbach, Thomas; Eschenbach, Annette

2016-04-01

In dry environments with a sparse vegetation cover, understory evapotranspiration is a major component of the ecosystem water balance. Consequently, knowledge on the size of evapotranspiration fluxes and the driving factors is important for our understanding of the hydrological cycle. Understory evapotranspiration is made up of soil evaporation and plant transpiration. Soil evaporation can be measured directly from patches free of vegetation. However, when understory vegetation is present distinguishing between soil evaporation and plant transpiration is challenging. In this study, we aim to partition understory evapotranspiration based on an approach that combines the measurements of water-vapour fluxes using the closed chamber method with measurements of the isotopic composition of water vapour. The measurements were done in the framework of SASSCAL (Southern African Science Service Centre for Climate Change and Adaptive Land Management). The study sites were located in three different semi-arid ecosystems in Namibia: thornbush savanna, Baikiaea woodland and shrubland. At each site measurements were done under tree canopies as well as at unshaded areas between the canopies. We measured evaporation from the bare soil and evapotranspiration from patches covered with herbaceous species and shrubs using a transparent chamber connected with an infrared gas analyser (LI-8100A, LICOR Inc.). The stable isotope composition of water vapour inside the chamber and depth profiles of soil water stable isotopes were determined in-situ using a tuneable off-axis integrated cavity output spectroscope (OA-ICOS, Los Gatos Research, DLT 100). Xylem samples were extracted using the cryogenic vacuum extraction method and the isotopic composition of the extracted water was measured subsequently with a cavity-ring-down spectrometer (CRDS L2120-i, Picarro Inc.). We will present the quantified fluxes of understory evapotranspiration measured in the three different ecosystems, show the

Changes of contact pressure and area in patellofemoral joint after different meniscectomies.

PubMed

Bai, Bo; Shun, Hui; Yin, Zhi Xun; Liao, Zhuang-Wen; Chen, Ni

2012-05-01

We investigated the contact pressure and area of the patellofemoral joint both before and after different meniscectomies to provide a biomechanical basis for selecting meniscectomy and its clinical application for meniscus injuries. Six fresh cadaveric knees were used in the study. Using Staubli robots and an ultra-low-min-type pressure-sensitive tablet, changes in contact area and stress in the patellofemoral joint were measured at various flexion angles following different parts and degrees of meniscectomy. The patellofemoral contact area enlarged with the increase of knee flexion angle. From the values obtained from contact areas and average contact pressure of the patellofemoral joint, we found no significant difference between partial meniscectomy and intact knees, but a significant difference was found between total meniscectomy and intact knees. The contact area after lateral meniscectomy was statistically less than that of intact knees. The mean patellofemoral contact pressure after lateral meniscectomy was larger than in intact knees at each angle of flexion. No significant difference in contact area was observed between intact knees and medial meniscectomy. The average patellofemoral contact pressure after medial meniscectomy was larger than in intact knees from 0° ~ 30° of knee flexion, and no significant differences were found between intact knees and medial meniscectomy while knee bending from 60° to 90°. Different meniscectomies result in high contact pressure or disordered distribution of contact pressure, which may be the cause of postoperative patellofemoral degenerative arthrosis.

Acute tamponade alters subendo- and subepicardial pressure-flow relations differently during vasodilation.

PubMed

Kingma, J G; Martin, J; Rouleau, J R

1994-07-01

Instantaneous diastolic left coronary artery pressure-flow relations (PFR) shift during acute tamponade as pressure surrounding the heart increases. Coronary pressure at zero flow (Pf = 0) on the linear portion of the PFR is the weighted mean of the different myocardial waterfall pressures, the distribution of which varies across the left ventricular wall during diastole. However, instantaneous PFR measured in large epicardial coronary arteries cannot be used to estimate Pf = 0 in the different myocardial tissue layers. During coronary vasodilatation in a capacitance-free model, myocardial PFR differs from subendocardium to subepicardium. Therefore, we studied the effects of acute tamponade during maximal pharmacology induced coronary vasodilatation on myocardial PFR in in situ anesthetized dogs. Tamponade reduced cardiac output, aortic pressure, and coronary blood flow. Results demonstrate that different mechanisms influence distribution of myocardial blood flow during tamponade. Subepicardial vascular resistance is unchanged and the extrapolated Pf = 0 is increased, thereby shifting PFR to a higher intercept on the pressure axis. Subendocardial vascular resistance is increased while the extrapolated Pf = 0 remains unchanged. Results indicate that in the setting of acute tamponade with coronary vasodilatation different mechanisms regulate the distribution of myocardial blood flow: in the subepicardium only outflow pressure increases, whereas in the subendocardium only vascular resistance increases.

Difference in blood pressure measurements between arms: methodological and clinical implications.

PubMed

Clark, Christopher E

2015-01-01

Differences in blood pressure measurements between arms are commonly encountered in clinical practice. If such differences are not excluded they can delay the diagnosis of hypertension and can lead to poorer control of blood pressure levels. Differences in blood pressure measurements between arms are associated cross sectionally with other signs of vascular disease such as peripheral arterial disease or cerebrovascular disease. Differences are also associated prospectively with increased cardiovascular mortality and morbidity and all cause mortality. Numbers of publications on inter-arm difference are rising year on year, indicating a growing interest in the phenomenon. The prevalence of an inter-arm difference varies widely between reports, and is correlated with the underlying cardiovascular risk of the population studied. Prevalence is also sensitive to the method of measurement used. This review discusses the prevalence of an inter-arm difference in different populations and addresses current best practice for the detection and the measurement of a difference. The evidence for clinical and for vascular associations of an inter-arm difference is presented in considering the emerging role of an inter-arm blood pressure difference as a novel risk factor for increased cardiovascular morbidity and mortality. Competing aetiological explanations for an inter-arm difference are explored, and gaps in our current understanding of this sign, along with areas in need of further research, are considered.

A Theoretical Study of Vapour Phase Nucleation of the Rocket Propellant N2O4

NASA Astrophysics Data System (ADS)

Pal, P.

2003-05-01

The residual vapour of a rocket fuel at the venting stage develops a potential aerodynamic problem which is linked with the vapour phase nucleation phenomena of the propellant. This study, based entirely on molecular treatment, addresses the problem by focusing specifically on the N2O4 propellant which is used in the ARIANE flight. The phenomenon is examined by considering the thermodynamic free energies of N2O4 clusters, leading to the evaluation of nucleation flux rates of critical nuclei at incipient nucleation. Preliminary examinations of the kinetics of flux pulses provide basic explanation from a molecular perspective.

Thermal Hysteresis of MEMS Packaged Capacitive Pressure Sensor (CPS) Based 3C-SiC

NASA Astrophysics Data System (ADS)

Marsi, N.; Majlis, B. Y.; Mohd-Yasin, F.; Hamzah, A. A.; Mohd Rus, A. Z.

2016-11-01

Presented herein are the effects of thermal hysteresis analyses of the MEMS packaged capacitive pressure sensor (CPS). The MEMS CPS was employed on Si-on-3C-SiC wafer that was performed using the hot wall low-pressure chemical vapour deposition (LPCVD) reactors at the Queensland Micro and Nanotechnology Center (QMNC), Griffith University and fabricated using the bulk-micromachining process. The MEMS CPS was operated at an extreme temperature up to 500°C and high external pressure at 5.0 MPa. The thermal hysteresis phenomenon that causes the deflection, strain and stress on the 3C-SiC diaphragm spontaneously influence the MEMS CPS performances. The differences of temperature, hysteresis, and repeatability test were presented to demonstrate the functionality of the MEMS packaged CPS. As expected, the output hysteresis has a low hysteresis (less than 0.05%) which has the hardness greater than the traditional silicon. By utilizing this low hysteresis, it was revealed that the MEMS packaged CPS has high repeatability and stability of the sensor.

Alcohol vapour detection at the three phase interface using enzyme-conducting polymer composites.

PubMed

Winther-Jensen, Orawan; Kerr, Robert; Winther-Jensen, Bjorn

2014-02-15

Immobilisation of enzymes on a breathable electrode can be useful for various applications where the three-phase interface between gas or chemical vapour, electrolyte and electrode is crucial for the reaction. In this paper, we report the further development of the breathable electrode concept by immobilisation of alcohol dehydrogenase into vapour-phase polymerised poly(3,4-ethylene dioxythiophene) that has been coated onto a breathable membrane. Typical alcohol sensing, whereby the coenzyme β-Nicotinamide adenine dinucleotide (NADH) is employed as a redox-mediator, was successfully used as a model reaction for the oxidation of ethanol. This indicates that the ethanol vapour from the backside of the membrane has access to the active enzyme embedded in the electrode. The detecting range of the sensor is suitable for the detection of ethanol in fruit juices and for the baseline breath ethanol concentration of drunken driving. After continuous operation for 4.5h the system only showed a 20% decrease in the current output. The electrodes maintained 62% in current output after being refrigerated for 76 days. This work is continuing the progress of the immobilisation of specific enzymes for certain electrochemical reactions whereby the three-phase interface has to be maintained and/or the simultaneous separation of gas from liquid is required. © 2013 Elsevier B.V. All rights reserved.

Effect of high-pressure homogenization on different matrices of food supplements.

PubMed

Martínez-Sánchez, Ascensión; Tarazona-Díaz, Martha Patricia; García-González, Antonio; Gómez, Perla A; Aguayo, Encarna

2016-12-01

There is a growing demand for food supplements containing high amounts of vitamins, phenolic compounds and mineral content that provide health benefits. Those functional compounds have different solubility properties, and the maintenance of their compounds and the guarantee of their homogenic properties need the application of novel technologies. The quality of different drinkable functional foods after thermal processing (0.1 MPa) or high-pressure homogenization under two different conditions (80 MPa, 33 ℃ and 120 MPa, 43 ℃) was studied. Physicochemical characteristics and sensory qualities were evaluated throughout the six months of accelerated storage at 40 ℃ and 75% relative humidity (RH). Aroma and color were better maintained in high-pressure homogenization-treated samples than the thermally treated ones, which contributed significantly to extending their shelf life. The small particle size obtained after high-pressure homogenization treatments caused differences in turbidity and viscosity with respect to heat-treated samples. The use of high-pressure homogenization, more specifically, 120 MPa, provided active ingredient homogeneity to ensure uniform content in functional food supplements. Although the effect of high-pressure homogenization can be affected by the food matrix, high-pressure homogenization can be implemented as an alternative to conventional heat treatments in a commercial setting within the functional food supplement or pharmaceutical industry. © The Author(s) 2016.

Using Peltier Cells to Study Solid-Liquid-Vapour Transitions and Supercooling

ERIC Educational Resources Information Center

Torzo, Giacomo; Soletta, Isabella; Branca, Mario

2007-01-01

We propose an apparatus for teaching experimental thermodynamics in undergraduate introductory courses, using thermoelectric modules and a real-time data acquisition system. The device may be made at low cost, still providing an easy approach to the investigation of liquid-solid and liquid-vapour phase transitions and of metastable states…

Automated calibration of laser spectrometer measurements of δ18 O and δ2 H values in water vapour using a Dew Point Generator.

PubMed

Munksgaard, Niels C; Cheesman, Alexander W; Gray-Spence, Andrew; Cernusak, Lucas A; Bird, Michael I

2018-06-30

Continuous measurement of stable O and H isotope compositions in water vapour requires automated calibration for remote field deployments. We developed a new low-cost device for calibration of both water vapour mole fraction and isotope composition. We coupled a commercially available dew point generator (DPG) to a laser spectrometer and developed hardware for water and air handling along with software for automated operation and data processing. We characterised isotopic fractionation in the DPG, conducted a field test and assessed the influence of critical parameters on the performance of the device. An analysis time of 1 hour was sufficient to achieve memory-free analysis of two water vapour standards and the δ 18 O and δ 2 H values were found to be independent of water vapour concentration over a range of ≈20,000-33,000 ppm. The reproducibility of the standard vapours over a 10-day period was better than 0.14 ‰ and 0.75 ‰ for δ 18 O and δ 2 H values, respectively (1 σ, n = 11) prior to drift correction and calibration. The analytical accuracy was confirmed by the analysis of a third independent vapour standard. The DPG distillation process requires that isotope calibration takes account of DPG temperature, analysis time, injected water volume and air flow rate. The automated calibration system provides high accuracy and precision and is a robust, cost-effective option for long-term field measurements of water vapour isotopes. The necessary modifications to the DPG are minor and easily reversible. Copyright © 2018 John Wiley & Sons, Ltd.

One-dimensional pore pressure diffusion of different grain-fluid mixtures

NASA Astrophysics Data System (ADS)

von der Thannen, Magdalena; Kaitna, Roland

2015-04-01

During the release and the flow of fully saturated debris, non-hydrostatic fluid pressure can build up and probably dissipate during the event. This excess fluid pressure has a strong influence on the flow and deposition behaviour of debris flows. Therefore, we investigate the influence of mixture composition on the dissipation of non-hydrostatic fluid pressures. For this we use a cylindrical pipe of acrylic glass with installed pore water pressure sensors in different heights and measure the evolution of the pore water pressure over time. Several mixtures with variable content of fine sediment (silt and clay) and variable content of coarse sediment (with fixed relative fractions of grains between 2 and 32 mm) are tested. For the fines two types of clay (smectite and kaolinite) and loam (Stoober Lehm) are used. The analysis is based on the one-dimensional consolidation theory which uses a diffusion coefficient D to model the decay of excess fluid pressure over time. Starting from artificially induced super-hydrostatic fluid pressures, we find dissipation coefficients ranging from 10-5 m²/s for liquid mixtures to 10-8 m²/s for viscous mixtures. The results for kaolinite and smectite are quite similar. For our limited number of mixtures the effect of fines content is more pronounced than the effect of different amounts of coarse particles.

Chronic psychological effects of exposure to mercury vapour among chlorine-alkali plant workers.

PubMed

Pranjić, N; Sinanović, O; Jakubović, R

2003-01-01

Quantitative assessment of nervous system function is essential in characterising the nature and extent of impairment in individuals experiencing symptoms following work-place mercury vapour exposure. The purpose of this study was the application of standardised tests of behavioural, psychomotor and memory function to understand the neuropsychological effects of mercury in occupationally exposed chlorine-alkali plant workers. The study comprised 45 workers at a chlorine-alkali plant with the mean age of 39.36 +/- 5.94 years, who had been exposed to daily inhalation of mercury vapour over long-term employment of 16.06 +/- 4.29 years. The cumulative mercury index was 155.32 +/- 95.02 micrograms/g creatinine, the mean of urinary mercury concentrations on the first day of the study was 119.50 +/- 157.24 micrograms/g creatinine, and the mean of urinary mercury concentrations 120 days after cessation of exposure was 21.70 +/- 26.07 micrograms/g creatinine. The analysis included tests of behavioural, psychomotor and memory function. The behavioural test battery consisted of: Environmental Worry Scale (EWS), Minnesota Modified Personal Inventory (MMPI-2), Purdue standard 25 minute test, and adapted, 10 minutes test, Bender's Visual-Motor Gestalt test (BGT), and Eysenck Personality Inventory (EPQ). The data were compared to a control group of 32 not directly exposed workers. In the mercury vapour exposed workers with relatively high level exposure to inorganic mercury vapour (TWA/TLV = 0.12 mg/m3/0.025 mg/m3) we identified somatic depression-hypochondria symptoms with higher scores for scales: hysteria (P < 0.001), schizoid and psycho-asthenia (MMPI-2). The mercury-exposed workers had introvert behaviour (EPQ, MMPI-2). The cognitive disturbances in mercury-exposed workers were identified as: concentration difficulty, psychomotor, perceptual and motor coordination disturbances, and brain effects. We identified fine tremor of the hands in 34 out of 45 mercury-exposed workers

Persistent negative temperature response of mesophyll conductance in red raspberry (Rubus idaeus L.) leaves under both high and low vapour pressure deficits: a role for abscisic acid?

PubMed

Qiu, Changpeng; Ethier, Gilbert; Pepin, Steeve; Dubé, Pascal; Desjardins, Yves; Gosselin, André

2017-09-01

The temperature dependence of mesophyll conductance (g m ) was measured in well-watered red raspberry (Rubus idaeus L.) plants acclimated to leaf-to-air vapour pressure deficit (VPDL) daytime differentials of contrasting amplitude, keeping a fixed diurnal leaf temperature (T leaf ) rise from 20 to 35 °C. Contrary to the great majority of g m temperature responses published to date, we found a pronounced reduction of g m with increasing T leaf irrespective of leaf chamber O 2 level and diurnal VPDL regime. Leaf hydraulic conductance was greatly enhanced during the warmer afternoon periods under both low (0.75 to 1.5 kPa) and high (0.75 to 3.5 kPa) diurnal VPDL regimes, unlike stomatal conductance (g s ), which decreased in the afternoon. Consequently, the leaf water status remained largely isohydric throughout the day, and therefore cannot be evoked to explain the diurnal decrease of g m . However, the concerted diurnal reductions of g m and g s were well correlated with increases in leaf abscisic acid (ABA) content, thus suggesting that ABA can induce a significant depression of g m under favourable leaf water status. Our results challenge the view that the temperature dependence of g m can be explained solely from dynamic leaf anatomical adjustments and/or from the known thermodynamic properties of aqueous solutions and lipid membranes.​. © 2017 John Wiley & Sons Ltd.

Traditional uses of herbal vapour therapy in Manipur, North East India: an ethnobotanical survey.

PubMed

Ningthoujam, Sanjoy Singh; Das Talukdar, Anupam; Potsangbam, Kumar Singh; Choudhury, Manabendra Dutta

2013-05-02

Vapour-based medicines are an aspect of traditional medicine in North East India. However, no collective studies on this therapy in the region have been attempted. With the changing perception of traditional knowledge, documenting these herbal preparations and the subsequent development of baseline data for applications in further ethnopharmacological research are needed. To survey and document the plant species associated with vapour therapy in Manipur, North East India, and to evaluate these traditional practices. Semi-structured questionnaires were used to collect information from the Meitei community in the Imphal valley and the Jiribam area in Manipur. Traditional disease concepts were studied along with their corresponding medical terminologies. Plant samples collected from fields, healers' private collections and home gardens were identified. Evaluation of the ethnobotanical data was performed with a modified fidelity level index. In the study, 41 traditional disease complexes were treated by 13 different routes of administration using 48 mono-ingredient and 17 multi-ingredient compositions. Preparation methods included boiling in water (28%), burning the materials (48%), crushing the materials to release the aroma (21%) and slight heating of the materials (3%). Some of the mono-ingredient recipes reported in the study were observed to have similar uses in other parts of the world, whereas polyherbal remedies were found to be unique without any similar report. Many compositions mentioned in the paper are still used by the Meitei community. Traditional healers follow their own criteria for selecting medicinal plants. Plants recorded in this ethnobotanical study can suggest methods for selecting and identifying potentially effective plants for future drug candidates. Scientific characterisation of the herbal remedies can contribute to the endorsement of traditional vapour-based therapies in the modern health care systems. Findings from these "new usage

Inter-Arm Difference in Brachial Blood Pressure in the General Population of Koreans.

PubMed

Song, Bo Mi; Kim, Hyeon Chang; Shim, Jee-Seon; Lee, Myung Ha; Choi, Dong Phil

2016-05-01

We investigated the inter-arm difference in blood pressure of the general Korean population to identify associated factors. A total of 806 participants aged 30 to 64 years without history of major cardiovascular disease were analyzed in this cross-sectional study. They participated in the Cardiovascular and Metabolic Disease Etiology Research Center cohort study that began in 2013. Brachial blood pressure was measured simultaneously for both arms using an automated oscillometric device equipped with two cuffs in seated position. After five minutes of rest, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured three times. The average of the three measurements was used for analysis. Multivariate logistic regression models were used to identify factors associated with inter-arm differences in blood pressure. The mean inter-arm difference was 3.3 mmHg for SBP and 2.0 mmHg for DBP. Large inter-arm differences (≥10 mmHg) in SBP and in DBP were found in 3.7% and 0.9% of subjects, respectively. A large inter-arm difference in SBP was associated with mean SBP (p=0.002) and C-reactive protein (p=0.014) while a large inter-arm different in DBP was only associated with body mass index (p=0.015). Sex, age, and anti-hypertensive medication use were not associated with differences in inter-arm blood pressure. Large inter-arm difference in blood pressure is only present in a small portion of healthy Korean adults. Our findings suggest that high SBP, chronic inflammation, and obesity may be associated with larger difference in inter-arm blood pressure.

Mixed garnet laser crystals for water vapour DIAL transmitter

NASA Astrophysics Data System (ADS)

Treichel, Rainer; Czeranowsky, Christoph; Ileri, Bilge; Petermann, Klaus; Huber, Günter

2017-11-01

There are more or less well established technologies such as the optical-parametric-oscillator (OPO), the Raman-laser, and the Ti-Sapphire laser, which are able to emit laser light in the region of the water vapour absorption lines. For WALES the regions of about 935 nm, 942 nm, and 944 nm have been identified as the most suitable wavelength ranges. However, each of these laser designs is highly sophisticated. Current baseline for WALES is the Ti-Sapphire laser. A fourth possibility to achieve these wavelength ranges is to shift the groundstate laser lines (938 nm and 946 nm) of the Nd:YAG laser by replacing Aluminium and Yttrium by other rare earth elements. Changes of the host lattice characteristics lead to a shift of the upper and lower laser levels. These modified crystals are summarized under the name of "Mixed Garnet" crystals. Only the Mixed Garnet lasers can be pumped directly with diode laser and use a direct approach to generate the required laser pulses without frequency conversion. Therefore no additional non-linear crystals are needed and a higher electric to optical efficiency is expected as well as single frequency operation using spectral tuning elements like etalons. Such lasers have the great potential to fulfil the requirements and to become the preferred transmitter concept for WALES as well as for follow up missions. Within a ESA study several crystal compositions have been grown, spectrally characterised and analysed. Absorbed space radiation energy in the crystal lattice causes colour centres, which can reabsorb the pump and laser wavelength and consequently reduce the laser gain considerably. Co-dopants such as Chromium and Cerium are able to suppress the colour centres and are candidates for effective radiation hardening. The results of the crystal tuning, the co-doping with different radiation hardeners and the radiation tests will be presented. There applicability for a space based water vapour DIAL transmitter will be discussed.

Development of graphene nanoplatelet embedded polymer microcantilever for vapour phase explosive detection applications

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

Ray, Prasenjit; Pandey, Swapnil; Ramgopal Rao, V.

2014-09-28

In this work, a graphene based strain sensor has been reported for explosive vapour detection applications by exploiting the piezoresistive property of graphene. Instead of silicon based cantilevers, a low cost polymeric micro-cantilever platform has been used to fabricate this strain sensor by embedding the graphene nanoplatelet layer inside the beam. The fabricated devices were characterized for their mechanical and electromechanical behaviour. This device shows a very high gauge factor which is around ~144. Also the resonant frequency of these cantilevers is high enough such that the measurements are not affected by environmental noise. These devices have been used inmore » this work for reliable detection of explosive vapours such as 2,4,6-Trinitrotoluene down to parts-per-billion concentrations in ambient conditions.« less

Reducing ingress of organic vapours into homes situated on contaminated land.

PubMed

Crump, D; Brown, V; Rowley, J; Squire, R

2004-04-01

The efficacy of current landfill gas and radon mitigation measures for the prevention of ingress of organic vapours was investigated by the study of four houses situated on contaminated land in North West England. The chemical present in the ground of greatest concern for health due to exposure to vapour in the indoor air was hexachlorobutadiene (HCBD) and the concentration of this compound was used to assess the effectiveness of the remedial measures. A two stage remediation was undertaken. For a house with a solid floor the top surface of the floor was sealed and then for the second stage a fan was used to pressurise the soil gas beneath the house. In a house with a suspended timber floor, extra air bricks were installed to increase ventilation of the floor void and then a fan to further increase air exchange in the void. HCBD in air was monitored by both pumped and diffusive sampling methods. Control houses were also monitored that were not subject to remediation. It is concluded that the remedial measures used for radon protection of a suspended floor have the potential to reduce indoor HCBD concentrations by about 80%, at least in downstairs rooms (where initial levels were highest). The two techniques used for properties with solid floors do not appear to be as effective, and no benefit at all was seen without making allowances for changes in concentration that occurred in the control house over the same period. Further work is required to test the efficacy of the techniques over a longer period and under different circumstances of type of contamination and building characteristics.

Generational Differences in Resistance to Peer Pressure among Mexican-Origin Adolescents.

ERIC Educational Resources Information Center

Umana-Taylor, Adriana J.; Bamaca-Gomez, Mayra Y.

2003-01-01

Examined whether Mexican origin adolescents who varied by generational status would differ in their resistance to peer pressure. After controlling for gender, resistance to peer pressure varied significantly by generational status. Adolescents with no familial births in the United States were significantly more resistant to peer pressure than…

Interarm blood pressure difference in a post-stroke population.

PubMed

Gaynor, Eva; Brewer, Linda; Mellon, Lisa; Hall, Patricia; Horgan, Frances; Shelley, Emer; Dolan, Eamonn; Hickey, Anne; Bennett, Kathleen; Williams, David J

2017-09-01

An increased interarm systolic blood pressure (SBP) difference of ≥10 mm Hg is associated with increased cardiovascular risk and a difference of ≥15 mm Hg with increased cerebrovascular risk. The stroke population presents a high-risk group for future cardiovascular and cerebrovascular events and therefore estimation of interarm SBP difference as a predictive tool may assist with further secondary stroke prevention. The aim of the study was to determine the prevalence of interarm SBP and diastolic blood pressure difference in a post-stroke population. A comprehensive assessment of secondary risk factors along with blood pressure measurements were taken 6-months' post-ischemic stroke from the Action on Secondary Prevention Interventions and Rehabilitation in Stroke cohort. Descriptive and logistic regression analyses were performed. Odds ratios and 95% confidence intervals are presented. Two hundred thirty-eight (M: F,139:99; mean age, 68.4 years) of 256 patients followed up at 6 months post-stroke had suitable blood pressure readings from both arms. Ninety-six patients (40.3%) had an interarm SBP difference of ≥10 mm Hg and 49 (20.6%) had a difference of ≥15 mm Hg. A history of hypertension, diabetes, smoking, and obesity was not significantly associated with an increased risk of interarm SBP difference. After multivariate logistic analysis, a history of alcohol excess was associated with an increased IASBP ≥15 mm Hg (odds ratio 2.32, 95% confidence interval 1.03-5.22). We have demonstrated that interarm SBP difference is commonly seen in a post stroke population. Copyright © 2017 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.

Inter-Arm Difference in Brachial Blood Pressure in the General Population of Koreans

PubMed Central

Song, Bo Mi; Shim, Jee-Seon; Lee, Myung Ha; Choi, Dong Phil

2016-01-01

Background and Objectives We investigated the inter-arm difference in blood pressure of the general Korean population to identify associated factors. Subjects and Methods A total of 806 participants aged 30 to 64 years without history of major cardiovascular disease were analyzed in this cross-sectional study. They participated in the Cardiovascular and Metabolic Disease Etiology Research Center cohort study that began in 2013. Brachial blood pressure was measured simultaneously for both arms using an automated oscillometric device equipped with two cuffs in seated position. After five minutes of rest, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured three times. The average of the three measurements was used for analysis. Multivariate logistic regression models were used to identify factors associated with inter-arm differences in blood pressure. Results The mean inter-arm difference was 3.3 mmHg for SBP and 2.0 mmHg for DBP. Large inter-arm differences (≥10 mmHg) in SBP and in DBP were found in 3.7% and 0.9% of subjects, respectively. A large inter-arm difference in SBP was associated with mean SBP (p=0.002) and C-reactive protein (p=0.014) while a large inter-arm different in DBP was only associated with body mass index (p=0.015). Sex, age, and anti-hypertensive medication use were not associated with differences in inter-arm blood pressure. Conclusion Large inter-arm difference in blood pressure is only present in a small portion of healthy Korean adults. Our findings suggest that high SBP, chronic inflammation, and obesity may be associated with larger difference in inter-arm blood pressure. PMID:27275174

Boiling vapour-type fluids from the Nifonea vent field (New Hebrides Back-Arc, Vanuatu, SW Pacific): Geochemistry of an early-stage, post-eruptive hydrothermal system

NASA Astrophysics Data System (ADS)

Schmidt, Katja; Garbe-Schönberg, Dieter; Hannington, Mark D.; Anderson, Melissa O.; Bühring, Benjamin; Haase, Karsten; Haruel, Christy; Lupton, John; Koschinsky, Andrea

2017-06-01

In 2013, high-temperature vent fluids were sampled in the Nifonea vent field. This field is located within the caldera of a large shield-type volcano of the Vate Trough, a young extensional rift in the New Hebrides back-arc. Hydrothermal venting occurs as clear and black smoker fluids with temperatures up to 368 °C, the hottest temperatures measured so far in the western Pacific. The physico-chemical conditions place the fluids within the two-phase field of NaCl-H2O, and venting is dominated by vapour phase fluids with Cl concentrations as low as 25 mM. The fluid composition, which differs between the individual vent sites, is interpreted to reflect the specific geochemical fluid signature of a hydrothermal system in its initial, post-eruptive stage. The strong Cl depletion is accompanied by low alkali/Cl ratios compared to more evolved hydrothermal systems, and very high Fe/Cl ratios. The concentrations of REY (180 nM) and As (21 μM) in the most Cl-depleted fluid are among the highest reported so far for submarine hydrothermal fluids, whereas the inter-element REY fractionation is only minor. The fluid signature, which has been described here for the first time in a back-arc setting, is controlled by fast fluid passage through basaltic volcanic rocks, with extremely high water-rock ratios and only limited water-rock exchange, phase separation and segregation, and (at least) two-component fluid mixing. Metals and metalloids are unexpectedly mobile in the vapour phase fluids, and the strong enrichments of Fe, REY, and As highlight the metal transport capacity of low-salinity, low-density vapours at the specific physico-chemical conditions at Nifonea. One possible scenario is that the fluids boiled before the separated vapour phase continued to react with fresh glassy lavas. The mobilization of metals is likely to occur by leaching from fresh glass and grain boundaries and is supported by the high water/rock ratios. The enrichment of B and As is further controlled

Ideal resuscitation pressure for uncontrolled hemorrhagic shock in different ages and sexes of rats

PubMed Central

2013-01-01

Introduction Our previous studies demonstrated that 50-60 mmHg mean arterial blood pressure was the ideal target hypotension for uncontrolled hemorrhagic shock during the active hemorrhage in sexually mature rats. The ideal target resuscitation pressure for immature and older rats has not been determined. Methods To elucidate this issue, using uncontrolled hemorrhagic-shock rats of different ages and sexes (6 weeks, 14 weeks and 1.5 years representing pre-adult, adult and older rats, respectively), the resuscitation effects of different target pressures (40, 50, 60, 70 and 80 mmHg) on uncontrolled hemorrhagic shock during active hemorrhage and the age and sex differences were observed. Results Different target resuscitation pressures had different resuscitation outcomes for the same age and sex of rats. The optimal target resuscitation pressures for 6-week-old, 14-week-old and 1.5-year-old rats were 40 to 50 mmHg, 50 to 60 mmHg and 70 mmHg respectively. Ideal target resuscitation pressures were significantly superior to other resuscitation pressures in improving the hemodynamics, blood perfusion, organ function and animal survival of uncontrolled hemorrhagic-shock rats (P < 0.01). For same target resuscitation pressures, the beneficial effect on hemorrhagic shock had a significant age difference (P < 0.01) but no sex difference (P > 0.05). Different resuscitation pressures had no effect on coagulation function. Conclusion Hemorrhagic-shock rats at different ages have different target resuscitation pressures during active hemorrhage. The ideal target resuscitation hypotension for 6-week-old, 14-week-old and 1.5-year-old rats was 40 to 50 mmHg, 50 to 60 mmHg and 70 mmHg, respectively. Their resuscitation effects have significant age difference but had no sex difference. PMID:24020401

Novel method for water vapour monitoring using wireless communication networks measurements

NASA Astrophysics Data System (ADS)

David, N.; Alpert, P.; Messer, H.

2009-04-01

We propose a new technique for monitoring near-surface water vapour, by estimating humidity from data collected through existing wireless communication networks. Water vapour plays a crucial part in a variety of atmospheric processes. As the most influential of greenhouse gases, it absorbs long-wave terrestrial radiation. The water vapour cycle of evaporation and recondensation is a major energy redistributing mechanism transferring heat energy from the Earth's surface to the atmosphere. Additionally, humidity has an important role in weather forecasting as a key variable required for initialization of atmospheric models and hazard warning techniques. However, current methods of monitoring humidity suffer from low spatial resolution, high cost or a lack of precision when measuring near ground levels. Weather conditions and atmospheric phenomena affect the electromagnetic channel, causing attenuations to the radio signals. Thus, wireless communication networks are in effect built-in environmental monitoring facilities. The wireless microwave links, used in these networks, are widely deployed by cellular providers for backhaul communication between base stations, a few tens of meters above ground level. As a result, the proposed method can provide moisture observations at high temporal and spatial resolution. Further, the implementation cost is minimal, since the data used is already collected and saved by the cellular operators. In addition - many of these links are installed in areas where access is difficult such as orographic terrain and complex topography. As such, our method enables measurements in places that have been hard to measure in the past, or have never been measured before. The technique is restricted to weather conditions which include absence of rain, fog or clouds along the propagation path. We present results from real-data measurements taken from microwave links used in a backhaul cellular network that show very good agreement with surface

Investigation of the vapour-plasma plume in the welding of titanium by high-power ytterbium fibre laser radiation

NASA Astrophysics Data System (ADS)

Bykovskiy, D. P.; Petrovskii, V. N.; Uspenskiy, S. A.

2015-03-01

The vapour-plasma plume produced in the welding of 6-mm thick VT-23 titanium alloy plates by ytterbium fibre laser radiation of up to 10 kW power is studied in the protective Ar gas medium. High-speed video filming of the vapour-plasma plume is used to visualise the processes occurring during laser welding. The coefficient of inverse bremsstrahlung by the welding plasma plume is calculated from the data of the spectrometric study.

Effect of different pressure magnitudes on hypertrophic scar in a Chinese population.

PubMed

Candy, Lai Hoi Yan; Cecilia, Li-Tsang Wai Ping; Ping, Zheng Yong

2010-12-01

This study aimed to investigate the effect of different pressure magnitudes on treatment outcomes of hypertrophic scars, and determine pressure loss over time. A randomized clinical trial was adopted. 53 hypertrophic scar samples from 17 Chinese participants were recruited and randomly assigned into a high pressure group (20-25 mmHg) and low pressure group (10-15 mmHg) for a five-month intervention program. The scars were assessed objectively before intervention and monthly after intervention for thickness, color (redness, yellowness and lightness) and scar pliability. Pressure magnitude at each assessment was also measured. Two-way repeated ANOVA was used to compare for differences between groups. The results showed that both levels of pressure produced reduction in scar thickness and redness, but the improvement in the high pressure group was statistically better than that of the counterpart (both p<0.05). Monthly pressure measurement revealed that pressure loss in the high pressure group was more severe. However, no major changes in other color parameters and pliability were observed for both the groups. High pressure was demonstrated to be more effective for scar management, but it was also more prone to higher pressure loss. Pressure therapy integrated with regular monitoring of the interface pressure is suggested to improve its therapeutic efficacy. Copyright © 2010 Elsevier Ltd and ISBI. All rights reserved.

An ex vivo porcine skin model to evaluate pressure-reducing devices of different mechanical properties used for pressure ulcer prevention.

PubMed

Yeung, Ching-Yan C; Holmes, David F; Thomason, Helen A; Stephenson, Christian; Derby, Brian; Hardman, Matthew J

2016-11-01

Pressure ulcers are complex wounds caused by pressure- and shear-induced trauma to skin and underlying tissues. Pressure-reducing devices, such as dressings, have been shown to successfully reduce pressure ulcer incidence, when used in adjunct to pressure ulcer preventative care. While pressure-reducing devices are available in a range of materials, with differing mechanical properties, understanding of how a material's mechanical properties will influence clinical efficacy remains limited. The aim of this study was to establish a standardized ex vivo model to allow comparison of the cell protection potential of two gel-like pressure-reducing devices with differing mechanical properties (elastic moduli of 77 vs. 35 kPa). The devices also displayed differing energy dissipation under compressive loading, and resisted strain differently under constant load in compressive creep tests. To evaluate biological efficacy we employed a new ex vivo porcine skin model, with a confirmed elastic moduli closely matching that of human skin (113 vs. 119 kPa, respectively). Static loads up to 20 kPa were applied to porcine skin ex vivo with subsequent evaluation of pressure-induced cell death and cytokine release. Pressure application alone increased the percentage of epidermal apoptotic cells from less than 2% to over 40%, and increased cellular secretion of the pro-inflammatory cytokine TNF-alpha. Co-application of a pressure-reducing device significantly reduced both cellular apoptosis and cytokine production, protecting against cellular damage. These data reveal new insight into the relationship between mechanical properties of pressure-reducing devices and their biological effects. After appropriate validation of these results in clinical pressure ulcer prevention with all tissue layers present between the bony prominence and external surface, this ex vivo porcine skin model could be widely employed to optimize design and evaluation of devices aimed at reducing pressure

[Thermodynamics of drug polymorphism: domains and stability hierarchy by pressure temperature diagram. Application to the tetramorphism of fananserine].

PubMed

Toscani, S

2002-05-01

In this communication, an application of classical thermodynamics to crystalline solid state polymorphism is shown to allow stability p, T domains and stability hierarchy among crystalline phases of a polymorph to be defined by constructing the unary p, T phase diagram. The three topological rules upon which this construction is founded are presented; the first one is a straight consequence of the least vapour pressure criterion by Ostwald. Calculation of triple point co-ordinates and of two-phase equilibrium curves is based upon using both thermodynamic and crystallographic data obtained at ordinary pressure. Clapeyron equation allows the slopes of the straight lines representing equilibria between condensed phases to be calculated and, hence, triple points situated at high or negative pressure to be determined. On the other hand, the hierarchy among the thermodynamic stability degrees of the crystalline varieties may be inferred from the location of the sublimation curves, by merely acknowledging inequalities among vapour pressures at each temperature on the whole T-range. These building-up processes are pointed out by outlining the achievement of a phase diagram related to the tetramorphism of fananserine, an anxiolytic drug. Three out four crystalline forms, namely phases II, III and IV, possess their own stability domain, although those belonging to phases II and III are limited at high pressure by that of phase IV. Conversely, phase I is overall metastable and exhibits a whole monotropic behaviour.

Altered host resistance to Listeria monocytogenes in mice exposed to 1-chloroacetophenone (CN) vapours

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

Kumar, P.; Kumar, P.; Zachariah, K.

1992-06-01

Short term repeated exposure of 1-chloroacetophenone (CN) vapours at a concentration of 0.153 mg per litre for 15 minutes daily on 10 consecutive days in Swiss albino male mice resulted in increased mortality to Listeria monocytogenes. Significantly elevated bacterial growth was observed in the spleen and liver of the CN exposed animals. The increased bacterial count in these organs was evident within 4-6 days post challenge as compared to vehicle exposed infected and unexposed infected animals. Increased susceptibility to infection has been considered to be the function of immune alteration due to cumulative short term effects of CN vapour inhalation.more » This may be attributed to immunotoxic effects of CN on T-cells mediated macrophage functions.« less

Unambiguous detection of nitrated explosive vapours by fluorescence quenching of dendrimer films

NASA Astrophysics Data System (ADS)

Geng, Yan; Ali, Mohammad A.; Clulow, Andrew J.; Fan, Shengqiang; Burn, Paul L.; Gentle, Ian R.; Meredith, Paul; Shaw, Paul E.

2015-09-01

Unambiguous and selective standoff (non-contact) infield detection of nitro-containing explosives and taggants is an important goal but difficult to achieve with standard analytical techniques. Oxidative fluorescence quenching is emerging as a high sensitivity method for detecting such materials but is prone to false positives--everyday items such as perfumes elicit similar responses. Here we report thin films of light-emitting dendrimers that detect vapours of explosives and taggants selectively--fluorescence quenching is not observed for a range of common interferents. Using a combination of neutron reflectometry, quartz crystal microbalance and photophysical measurements we show that the origin of the selectivity is primarily electronic and not the diffusion kinetics of the analyte or its distribution in the film. The results are a major advance in the development of sensing materials for the standoff detection of nitro-based explosive vapours, and deliver significant insights into the physical processes that govern the sensing efficacy.

Surface and Thin Film Analysis during Metal Organic Vapour Phase Epitaxial Growth

NASA Astrophysics Data System (ADS)

Richter, Wolfgang

2007-06-01

In-situ analysis of epitaxial growth is the essential ingredient in order to understand the growth process, to optimize growth and last but not least to monitor or even control the epitaxial growth on a microscopic scale. In MBE (molecular beam epitaxy) in-situ analysis tools existed right from the beginning because this technique developed from Surface Science technology with all its electron based analysis tools (LEED, RHEED, PES etc). Vapour Phase Epitaxy, in contrast, remained for a long time in an empirical stage ("alchemy") because only post growth characterisations like photoluminescence, Hall effect and electrical conductivity were available. Within the last two decades, however, optical techniques were developed which provide similar capabilities as in MBE for Vapour Phase growth. I will discuss in this paper the potential of Reflectance Anisotropy Spectroscopy (RAS) and Spectroscopic Ellipsometry (SE) for the growth of thin epitaxial semiconductor layers with zincblende (GaAs etc) and wurtzite structure (GaN etc). Other techniques and materials will be also mentioned.

Unambiguous detection of nitrated explosive vapours by fluorescence quenching of dendrimer films.

PubMed

Geng, Yan; Ali, Mohammad A; Clulow, Andrew J; Fan, Shengqiang; Burn, Paul L; Gentle, Ian R; Meredith, Paul; Shaw, Paul E

2015-09-15

Unambiguous and selective standoff (non-contact) infield detection of nitro-containing explosives and taggants is an important goal but difficult to achieve with standard analytical techniques. Oxidative fluorescence quenching is emerging as a high sensitivity method for detecting such materials but is prone to false positives—everyday items such as perfumes elicit similar responses. Here we report thin films of light-emitting dendrimers that detect vapours of explosives and taggants selectively—fluorescence quenching is not observed for a range of common interferents. Using a combination of neutron reflectometry, quartz crystal microbalance and photophysical measurements we show that the origin of the selectivity is primarily electronic and not the diffusion kinetics of the analyte or its distribution in the film. The results are a major advance in the development of sensing materials for the standoff detection of nitro-based explosive vapours, and deliver significant insights into the physical processes that govern the sensing efficacy.

Unambiguous detection of nitrated explosive vapours by fluorescence quenching of dendrimer films

PubMed Central

Geng, Yan; Ali, Mohammad A.; Clulow, Andrew J.; Fan, Shengqiang; Burn, Paul L.; Gentle, Ian R.; Meredith, Paul; Shaw, Paul E.

2015-01-01

Unambiguous and selective standoff (non-contact) infield detection of nitro-containing explosives and taggants is an important goal but difficult to achieve with standard analytical techniques. Oxidative fluorescence quenching is emerging as a high sensitivity method for detecting such materials but is prone to false positives—everyday items such as perfumes elicit similar responses. Here we report thin films of light-emitting dendrimers that detect vapours of explosives and taggants selectively—fluorescence quenching is not observed for a range of common interferents. Using a combination of neutron reflectometry, quartz crystal microbalance and photophysical measurements we show that the origin of the selectivity is primarily electronic and not the diffusion kinetics of the analyte or its distribution in the film. The results are a major advance in the development of sensing materials for the standoff detection of nitro-based explosive vapours, and deliver significant insights into the physical processes that govern the sensing efficacy. PMID:26370931

The effect of coherent stirring on the advection–condensation of water vapour

PubMed Central

Vanneste, Jacques

2017-01-01

Atmospheric water vapour is an essential ingredient of weather and climate. The key features of its distribution can be represented by kinematic models which treat it as a passive scalar advected by a prescribed flow and reacting through condensation. Condensation acts as a sink that maintains specific humidity below a prescribed, space-dependent saturation value. To investigate how the interplay between large-scale advection, small-scale turbulence and condensation controls moisture distribution, we develop simple kinematic models which combine a single circulating flow with a Brownian-motion representation of turbulence. We first study the drying mechanism of a water-vapour anomaly released inside a vortex at an initial time. Next, we consider a cellular flow with a moisture source at a boundary. The statistically steady state attained shows features reminiscent of the Hadley cell such as boundary layers, a region of intense precipitation and a relative humidity minimum. Explicit results provide a detailed characterization of these features in the limit of strong flow. PMID:28690417

The effect of coherent stirring on the advection-condensation of water vapour

NASA Astrophysics Data System (ADS)

Tsang, Yue-Kin; Vanneste, Jacques

2017-06-01

Atmospheric water vapour is an essential ingredient of weather and climate. The key features of its distribution can be represented by kinematic models which treat it as a passive scalar advected by a prescribed flow and reacting through condensation. Condensation acts as a sink that maintains specific humidity below a prescribed, space-dependent saturation value. To investigate how the interplay between large-scale advection, small-scale turbulence and condensation controls moisture distribution, we develop simple kinematic models which combine a single circulating flow with a Brownian-motion representation of turbulence. We first study the drying mechanism of a water-vapour anomaly released inside a vortex at an initial time. Next, we consider a cellular flow with a moisture source at a boundary. The statistically steady state attained shows features reminiscent of the Hadley cell such as boundary layers, a region of intense precipitation and a relative humidity minimum. Explicit results provide a detailed characterization of these features in the limit of strong flow.

The effect of coherent stirring on the advection-condensation of water vapour.

PubMed

Tsang, Yue-Kin; Vanneste, Jacques

2017-06-01

Atmospheric water vapour is an essential ingredient of weather and climate. The key features of its distribution can be represented by kinematic models which treat it as a passive scalar advected by a prescribed flow and reacting through condensation. Condensation acts as a sink that maintains specific humidity below a prescribed, space-dependent saturation value. To investigate how the interplay between large-scale advection, small-scale turbulence and condensation controls moisture distribution, we develop simple kinematic models which combine a single circulating flow with a Brownian-motion representation of turbulence. We first study the drying mechanism of a water-vapour anomaly released inside a vortex at an initial time. Next, we consider a cellular flow with a moisture source at a boundary. The statistically steady state attained shows features reminiscent of the Hadley cell such as boundary layers, a region of intense precipitation and a relative humidity minimum. Explicit results provide a detailed characterization of these features in the limit of strong flow.

We didn't start this fireless vapour: e-cigarette legislation in Australia.

PubMed

Krawitz, Marilyn

2014-12-01

Electronic cigarettes (or e-cigarettes) are devices that heat a cartridge containing a solution that becomes a vapour for the user to inhale. The vapour may or may not contain nicotine. E-cigarettes do not contain tar and other toxins, which traditional cigarettes do, so they may be less damaging to people's health than smoking traditional cigarettes. However, no studies exist about the long-term effects of using e-cigarettes yet. It is illegal to sell e-cigarettes with nicotine in Australia, though Australians may import a three-month supply from overseas. It is legal to sell e-cigarettes with nicotine in some other jurisdictions, such as the United Kingdom and the European Union. This article argues that the Australian government should consider legalising the sale of e-cigarettes with nicotine in Australia for health, safety and economic reasons and to protect youth. If the sale of e-cigarettes with nicotine becomes legal, the Australian government must strictly regulate it.

Neural control of blood pressure in women: differences according to age

PubMed Central

Peinado, Ana B.; Harvey, Ronee E.; Hart, Emma C.; Charkoudian, Nisha; Curry, Timothy B.; Nicholson, Wayne T.; Wallin, B. Gunnar; Joyner, Michael J.; Barnes, Jill N.

2017-01-01

Purpose The blood pressure “error signal” represents the difference between an individual’s mean diastolic blood pressure and the diastolic blood pressure at which 50% of cardiac cycles are associated with a muscle sympathetic nerve activity burst (the “T50”). In this study we evaluated whether T50 and the error signal related to the extent of change in blood pressure during autonomic blockade in young and older women, to study potential differences in sympathetic neural mechanisms regulating blood pressure before and after menopause. Methods We measured muscle sympathetic nerve activity and blood pressure in 12 premenopausal (25±1 years) and 12 postmenopausal women (61±2 years) before and during complete autonomic blockade with trimethaphan camsylate. Results At baseline, young women had a negative error signal (−8±1 versus 2±1 mmHg, p<0.001; respectively) and lower muscle sympathetic nerve activity (15±1 versus 33±3 bursts/min, p<0.001; respectively) than older women. The change in diastolic blood pressure after autonomic blockade was associated with baseline T50 in older women (r=−0.725, p=0.008) but not in young women (r=−0.337, p=0.29). Women with the most negative error signal had the lowest muscle sympathetic nerve activity in both groups (young: r=0.886, p<0.001; older: r=0.870, p<0.001). Conclusions Our results suggest that there are differences in baroreflex control of muscle sympathetic nerve activity between young and older women, using the T50 and error signal analysis. This approach provides further information on autonomic control of blood pressure in women. PMID:28205011

Hydraulic High Pressure Valve Controller Using the In-Situ Pressure Difference

NASA Technical Reports Server (NTRS)

Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Hall, Jeffery L. (Inventor); Sherrit, Stewart (Inventor); Bao, Xiaoqi (Inventor)

2016-01-01

A hydraulic valve controller that uses an existing pressure differential as some or all of the power source for valve operation. In a high pressure environment, such as downhole in an oil or gas well, the pressure differential between the inside of a pipe and the outside of the pipe may be adequately large to drive a linear slide valve. The valve is operated hydraulically by a piston in a bore. When a higher pressure is applied to one end of the bore and a lower pressure to the other end, the piston moves in response to the pressure differential and drives a valve attached to it. If the pressure differential is too small to drive the piston at a sufficiently high speed, a pump is provided to generate a larger pressure differential to be applied. The apparatus is conveniently constructed using multiport valves, which can be rotary valves.

The effects of confining pressure and stress difference on static fatigue of granite

NASA Technical Reports Server (NTRS)

Kranz, R. L.

1979-01-01

Samples of Barre granite were creep tested at room temperature at confining pressures up to 2 kilobars. The time to fracture increased with decreasing stress difference at every pressure, but the rate of change of fracture time with respect to the stress difference increased with pressure. At 87% of the short-term fracture strength, the time to fracture increased from about 4 minutes at atmospheric pressure to longer than one day at 2 Kb of pressure. The inelastic volumetric strain at the onset of tertiary creep, delta, was constant within 25% at any particular pressure but increased with pressure in a manner analogous to the increase of strength with pressure. At the onset of tertiary creep, the number of cracks and their average length increased with pressure. The crack angle and crack length spectra were quite similar, however, at each pressure at the onset of tertiary creep.

Extreme pressure differences at 0900 NZST and winds across New Zealand

NASA Astrophysics Data System (ADS)

Salinger, M. James; Griffiths, Georgina M.; Gosai, Ashmita

2005-07-01

Trends in extremes in station daily sea-level pressure differences at 0900 NZST are examined, and extreme daily wind gusts, across New Zealand, since the 1960s. Annual time series were examined (with indices of magnitude and frequency over threshold percentiles) from the daily indices selected. These follow from earlier indices of normalized monthly mean sea-level pressure differences between station pairs, except the daily indices are not normalized. The frequency statistics quantify the number of extreme zonal (westerly and easterly), or extreme meridional (southerly or northerly), pressure gradient events. The frequency and magnitude of extreme westerly episodes has increased slightly over New Zealand, with a significant increase in the westerly extremes to the south of New Zealand. In contrast, the magnitude and frequency of easterly extremes has decreased over New Zealand, but increased to the south, with some trends weakly significant. The frequency and magnitude of daily southerly extremes has decreased significantly in the region.Extreme daily wind gust events at key climate stations in New Zealand and at Hobart, Australia, are highly likely to be associated with an extreme daily pressure difference. The converse was less likely to hold: extreme wind gusts were not always observed on days with extreme daily pressure difference, probably due to the strong influence that topography has on localized station winds. Significant correlations exist between the frequency indices and both annual-average mean sea-level pressures around the Australasian region and annual-average sea surface temperature (SST) anomalies in the Southern Hemisphere. These correlations are generally stronger for indices of extreme westerly or extreme southerly airflows. Annual-average pressures in the Tasman Sea or Southern Ocean are highly correlated to zonal indices (frequency of extreme westerlies). SST anomalies in the NINO3 region or on either side of the South Island are

Gender Differences in Behavioral and Neural Responses to Unfairness Under Social Pressure.

PubMed

Zheng, Li; Ning, Reipeng; Li, Lin; Wei, Chunli; Cheng, Xuemei; Zhou, Chu; Guo, Xiuyan

2017-10-18

Numerous studies have revealed the key role of social pressure on individuals' decision-making processes. However, the impact of social pressure on unfairness-related decision-making processes remains unclear. In the present study, we investigated how social pressure modulated men's and women's responses in an ultimatum game. Twenty women and eighteen men played the ultimatum game as responders in the scanner, where fair and unfair offers were tendered by proposers acting alone (low pressure) or by proposers endorsed by three supporters (high pressure). Results showed that men rejected more, whereas women accepted more unfair offers in the high versus low pressure context. Neurally, pregenual anterior cingulate cortex activation in women positively predicted their acceptance rate difference between contexts. In men, stronger right anterior insula activation and increased connectivity between right anterior insula and dorsal anterior cingulate cortex were observed when they receiving unfair offers in the high than low pressure context. Furthermore, more bilateral anterior insula and left dorsolateral prefrontal cortex activations were found when men rejected (relative to accepted) unfair offers in the high than low pressure context. These findings highlighted gender differences in the modulation of behavioral and neural responses to unfairness by social pressure.

Inter-arm blood pressure difference in type 2 diabetes: a barrier to effective management?

PubMed

Clark, Christopher E; Greaves, Colin J; Evans, Philip H; Dickens, Andy; Campbell, John L

2009-06-01

Previous studies have identified a substantial prevalence of a blood pressure difference between arms in various populations, but not patients with type 2 diabetes. Recognition of such a difference would be important as a potential cause of underestimation of blood pressure. To measure prevalence of an inter-arm blood pressure difference in patients with type 2 diabetes, and to estimate how frequently blood pressure measurements could be erroneously underestimated if an inter-arm difference is unrecognised. Cross-sectional study. Five surgeries covered by three general practices, Devon, England. Patients with type 2 diabetes underwent bilateral simultaneous blood pressure measurements using a validated protocol. Mean blood pressures were calculated for each arm to derive mean systolic and diastolic differences, and to estimate point prevalence of predefined magnitudes of difference. A total of 101 participants were recruited. Mean age was 66 years (standard deviation [SD] = 13.9 years); 59% were male, and mean blood pressure was 138/79 mmHg (SD = 15/10 mmHg). Ten participants (10%; 95% confidence interval [CI] = 4 to 16) had a systolic inter-arm difference > or =10 mmHg; 29 (29%; 95% CI = 20 to 38) had a diastolic difference >/=5 mmHg; and three (3%; 95% CI = 0 to 6) a diastolic difference > or =10 mmHg. No confounding variable was observed to account for the magnitude of an inter-arm difference. A systolic inter-arm difference > or =10 mmHg was observed in 10% of patients with diabetes. Failure to recognise this would misclassify half of these as normotensive rather than hypertensive using the lower-reading arm. New patients with type 2 diabetes should be screened for an inter-arm blood pressure difference.

Comparison of GOME-2/Metop total column water vapour with ground-based and in situ measurements

NASA Astrophysics Data System (ADS)

Kalakoski, N.; Kujanpää, J.; Sofieva, V.; Tamminen, J.; Grossi, M.; Valks, P.

2014-12-01

Total column water vapour product from the Global Ozone Monitoring Experiment-2 on board Metop-A and Metop-B satellites (GOME-2/Metop-A and GOME-2/Metop-B) produced by the Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M SAF) is compared with co-located radiosonde and Global Positioning System (GPS) observations. The comparisons are performed using recently reprocessed data by the GOME Data Processor (GDP) version 4.7. The comparisons are performed for the period of January 2007-July 2013 (GOME-2A) and from December 2012 to July 2013 (GOME-2B). Radiosonde data are from the Integrated Global Radiosonde Archive (IGRA) maintained by National Climatic Data Center (NCDC) and screened for soundings with incomplete tropospheric column. Ground-based GPS observations from COSMIC/SuomiNet network are used as the second independent data source. Good general agreement between GOME-2 and the ground-based observations is found. The median relative difference of GOME-2 to radiosonde observations is -2.7% for GOME-2A and -0.3% for GOME-2B. Against GPS observations, the median relative differences are 4.9 and 3.2% for GOME-2A and B, respectively. For water vapour total columns below 10 kg m-2, large wet biases are observed, especially against GPS observations. Conversely, at values above 50 kg m-2, GOME-2 generally underestimates both ground-based observations.

Validation of GOME-2/Metop total column water vapour with ground-based and in situ measurements

NASA Astrophysics Data System (ADS)

Kalakoski, Niilo; Kujanpää, Jukka; Sofieva, Viktoria; Tamminen, Johanna; Grossi, Margherita; Valks, Pieter

2016-04-01

The total column water vapour product from the Global Ozone Monitoring Experiment-2 on board Metop-A and Metop-B satellites (GOME-2/Metop-A and GOME-2/Metop-B) produced by the Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M SAF) is compared with co-located radiosonde observations and global positioning system (GPS) retrievals. The validation is performed using recently reprocessed data by the GOME Data Processor (GDP) version 4.7. The time periods for the validation are January 2007-July 2013 (GOME-2A) and December 2012-July 2013 (GOME-2B). The radiosonde data are from the Integrated Global Radiosonde Archive (IGRA) maintained by the National Climatic Data Center (NCDC). The ground-based GPS observations from the COSMIC/SuomiNet network are used as the second independent data source. We find a good general agreement between the GOME-2 and the radiosonde/GPS data. The median relative difference of GOME-2 to the radiosonde observations is -2.7 % for GOME-2A and -0.3 % for GOME-2B. Against the GPS, the median relative differences are 4.9 % and 3.2 % for GOME-2A and B, respectively. For water vapour total columns below 10 kg m-2, large wet biases are observed, especially against the GPS retrievals. Conversely, at values above 50 kg m-2, GOME-2 generally underestimates both ground-based observations.

A vapour phase assay for evaluating the antimicrobial activities of essential oils against bovine respiratory bacterial pathogens.

PubMed

Amat, S; Baines, D; Alexander, T W

2017-12-01

The objectives of this study were to develop a new assay for the evaluation of the antimicrobial activities of essential oils (EOs) in vapour phase and to demonstrate the antimicrobial activities of commercial EOs against BRPs. To achieve the first objective, a microtube cap containing 100 μl of EO was embedded in an agar plate. An agar plug (diameter 13 mm) inoculated with a bacterial suspension containing10 8  CFU per ml was then placed over the cap and incubated at 37°C for 24 h. Subsequently, bacteria were recovered from the agar plug by immersion in 5 ml of broth for 10 min, followed by vortexing for 30 s, and the broths were then plated for enumeration. To demonstrate the usefulness of the assay, nine commercial EOs derived from the following specific plants: ajowan, carrot seed, cinnamon leaf, citronella, fennel, ginger grass, lavender, rosemary and thyme were first evaluated for their vapour phase antimicrobial activities against Mannheimia haemolytica serotype 1. Selected EOs were further tested against Pasteurella multocida and Histophilus somni. The EOs of ajowan, thyme and cinnamon leaf completely or partially inhibited BRPs growth. This new assay provided reproducible results on the vapour phase antimicrobial activities of EOs against BRPs. These results support further study of EOs as a potential mitigation strategy against BRPs. In this study, we present a new vapour phase assay for evaluating the antimicrobial activities of essential oils (EO) against bovine respiratory pathogens (BRPs). Using this assay, we identified EOs, such as ajowan, thyme and cinnamon leaf, that can effectively inhibit growth of the BRPs Mannheimia haemolytica serotype 1, Pasteurella multocida and Histophilus somni. This is the first study to demonstrate the vapour phase antimicrobial activity of EOs against BRPs. © 2017 Her Majesty the Queen in Right of Canada. © 2017 The Society for Applied Microbiology Reproduced with the permission of the Minister of the

Lidar observations of low-level wind reversals over the Gulf of Lion and characterization of their impact on the water vapour variability

NASA Astrophysics Data System (ADS)

Di Girolamo, Paolo; Flamant, Cyrille; Cacciani, Marco; Summa, Donato; Stelitano, Dario; Richard, Evelyne; Ducrocq, Véronique; Fourrie, Nadia; Said, Frédérique

2017-02-01

Water vapour measurements from a ground-based Raman lidar and an airborne differential absorption lidar, complemented by high resolution numerical simulations from two mesoscale models (Arome-WMED and MESO-NH), are considered to investigate transition events from Mistral/Tramontane to southerly marine flow taking place over the Gulf of Lion in Southern France in the time frame September-October 2012, during the Hydrological Cycle in the Mediterranean Experiment (HyMeX) Special Observation Period 1 (SOP1). Low-level wind reversals associated with these transitions are found to have a strong impact on water vapour transport, leading to a large variability of the water vapour vertical and horizontal distribution. The high spatial and temporal resolution of the lidar data allow to monitor the time evolution of the three-dimensional water vapour field during these transitions from predominantly northerly Mistral/Tramontane flow to a predominantly southerly flow, allowing to identify the quite sharp separation between these flows, which is also quite well captured by the mesoscale models.

The water vapour radiometer of Paranal: homogeneity of precipitable water vapour from two years of operations

NASA Astrophysics Data System (ADS)

Kerber, Florian; Querel, Richard R.; Neureiter, Bianca

2015-04-01

A Low Humidity and Temperature Profiling (LHATPRO) microwave radiometer, manufactured by Radiometer Physics GmbH (RPG), is used to monitor sky conditions over ESO's Paranal observatory in support of VLT science operations. The unit measures several channels across the strong water vapour emission line at 183 GHz, necessary for resolving the low levels of precipitable water vapour (PWV) that are prevalent on Paranal (median ∼2.4 mm). The instrument consists of a humidity profiler (183-191 GHz), a temperature profiler (51-58 GHz), and an infrared camera (∼10 μm) for cloud detection. We present a statistical analysis of the homogeneity of all-sky PWV using 24 months of PWV observations. The question we tried to address was whether PWV is homogeneous enough across the sky such that service mode observations with the VLT can routinely be conducted with a user-provided constraint for PWV measured at zenith. We find the PWV over Paranal to be remarkably homogeneous across the sky down to 27.5° elevation with a median variation of 0.07 mm (rms). The homogeneity is a function of the absolute PWV but the relative variation is fairly constant at 2 to 3% (rms). Such variations will not be a significant issue for analysis of astronomical data. Users at ESO can specify PWV - measured at zenith - as an ambient constraint in service mode to enable, for instance, very demanding observations in the infrared. We conclude that in general it will not be necessary to add another observing constraint for PWV homogeneity to ensure integrity of observations. For demanding observations requiring very low PWV, where the relative variation is higher, the optimum support could be provided by observing with the LHATPRO in the same line-of-sight simultaneously. Such a mode of operations has already been tested but will have to be justified in terms of scientific gain before implementation can be considered. We plan to extend our analysis of PWV variations covering a larger parameters space

Investigation of the vapour-plasma plume in the welding of titanium by high-power ytterbium fibre laser radiation

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

Bykovskiy, D P; Petrovskii, V N; Uspenskiy, S A

2015-03-31

The vapour-plasma plume produced in the welding of 6-mm thick VT-23 titanium alloy plates by ytterbium fibre laser radiation of up to 10 kW power is studied in the protective Ar gas medium. High-speed video filming of the vapour-plasma plume is used to visualise the processes occurring during laser welding. The coefficient of inverse bremsstrahlung by the welding plasma plume is calculated from the data of the spectrometric study. (interaction of laser radiation with matter)

Differences in evolutionary pressure acting within highly conserved ortholog groups.

PubMed

Przytycka, Teresa M; Jothi, Raja; Aravind, L; Lipman, David J

2008-07-17

In highly conserved widely distributed ortholog groups, the main evolutionary force is assumed to be purifying selection that enforces sequence conservation, with most divergence occurring by accumulation of neutral substitutions. Using a set of ortholog groups from prokaryotes, with a single representative in each studied organism, we asked the question if this evolutionary pressure is acting similarly on different subgroups of orthologs defined as major lineages (e.g. Proteobacteria or Firmicutes). Using correlations in entropy measures as a proxy for evolutionary pressure, we observed two distinct behaviors within our ortholog collection. The first subset of ortholog groups, called here informational, consisted mostly of proteins associated with information processing (i.e. translation, transcription, DNA replication) and the second, the non-informational ortholog groups, mostly comprised of proteins involved in metabolic pathways. The evolutionary pressure acting on non-informational proteins is more uniform relative to their informational counterparts. The non-informational proteins show higher level of correlation between entropy profiles and more uniformity across subgroups. The low correlation of entropy profiles in the informational ortholog groups suggest that the evolutionary pressure acting on the informational ortholog groups is not uniform across different clades considered this study. This might suggest "fine-tuning" of informational proteins in each lineage leading to lineage-specific differences in selection. This, in turn, could make these proteins less exchangeable between lineages. In contrast, the uniformity of the selective pressure acting on the non-informational groups might allow the exchange of the genetic material via lateral gene transfer.

Does the position or contact pressure of the stethoscope make any difference to clinical blood pressure measurements: an observational study.

PubMed

Pan, Fan; Zheng, Dingchang; He, Peiyu; Murray, Alan

2014-12-01

This study aimed to investigate the effect of stethoscope position and contact pressure on auscultatory blood pressure (BP) measurement. Thirty healthy subjects were studied. Two identical stethoscopes (one under the cuff, the other outside the cuff) were used to simultaneously and digitally record 2 channels of Korotkoff sounds during linear cuff pressure deflation. For each subject, 3 measurements with different contact pressures (0, 50, and 100 mm Hg) on the stethoscope outside the cuff were each recorded at 3 repeat sessions. The Korotkoff sounds were replayed twice on separate days to each of 2 experienced listeners to determine systolic and diastolic BPs (SBP and DBP). Variance analysis was performed to study the measurement repeatability and the effect of stethoscope position and contact pressure on BPs. There was no significant BP difference between the 3 repeat sessions, between the 2 determinations from each listener, between the 2 listeners and between the 3 stethoscope contact pressures (all P > 0.06). There was no significant SBP difference between the 2 stethoscope positions at the 2 lower stethoscope pressures (P = 0.23 and 0.45), but there was a small (0.4 mm Hg, clinically unimportant) significant difference (P = 0.005) at the highest stethoscope pressure. The key result was that, DBP from the stethoscope under the cuff was significantly lower than that from outside the cuff by 2.8 mm Hg (P < 0.001, 95% confidence interval -3.5 to -2.1 mm Hg). Since it is known that the traditional Korotkoff sound method, with the stethoscope outside the cuff, tends to give a higher DBP than the true intra-arterial pressure, this study could suggest that the stethoscope position under the cuff, and closer to the arterial occlusion, might yield measurements closer to the actual invasive DBP.

Development of a low frost-point generator operating at sub-atmospheric pressure

NASA Astrophysics Data System (ADS)

Cuccaro, R.; Rosso, L.; Smorgon, D.; Beltramino, G.; Tabandeh, S.; Fernicola, V.

2018-05-01

A low frost-point generator (INRIM 03) operating at sub-atmospheric pressure has been designed and constructed at the Istituto Nazionale di Ricerca Metrologica (INRIM) as part of a calibration facility for upper-air sounding instruments. This new humidity generator covers the frost-point temperature range between  ‑99 °C and  ‑20 °C and works at any controlled pressure between 200 hPa and 1100 hPa, achieving a complete saturation of the carrier gas (nitrogen) in a single passage through a stainless steel isothermal saturator. The generated humid gas contains a water vapour amount fraction between 14  ×  10‑9 mol mol‑1 and 5  ×  10‑3 mol mol‑1. In this work the design of the generator is reported together with characterisation and performance evaluation tests. A preliminary validation of the INRIM 03 against one of the INRIM humidity standards in the common region is also included. Based on experimental test results, an initial uncertainty evaluation of the generated frost-point temperature, T fp, and water vapour amount fraction, x w, in the limited range down to  ‑75 °C at atmospheric pressure is reported. For the frost-point temperature, the uncertainty budget yields a total expanded uncertainty (k  =  2) of less than 0.028 °C, while for the mole fraction the budget yields a total expanded uncertainty of less than 10‑6 mol mol‑1.

The systolic blood pressure difference between arms and cardiovascular disease in the Framingham Heart Study.

PubMed

Weinberg, Ido; Gona, Philimon; O'Donnell, Christopher J; Jaff, Michael R; Murabito, Joanne M

2014-03-01

An increased interarm systolic blood pressure difference is an easily determined physical examination finding. The relationship between interarm systolic blood pressure difference and risk of future cardiovascular disease is uncertain. We described the prevalence and risk factor correlates of interarm systolic blood pressure difference in the Framingham Heart Study (FHS) original and offspring cohorts and examined the association between interarm systolic blood pressure difference and incident cardiovascular disease and all-cause mortality. An increased interarm systolic blood pressure difference was defined as ≥ 10 mm Hg using the average of initial and repeat blood pressure measurements obtained in both arms. Participants were followed through 2010 for incident cardiovascular disease events. Multivariable Cox proportional hazards regression analyses were performed to investigate the effect of interarm systolic blood pressure difference on incident cardiovascular disease. We examined 3390 (56.3% female) participants aged 40 years and older, free of cardiovascular disease at baseline, mean age of 61.1 years, who attended a FHS examination between 1991 and 1994 (original cohort) and from 1995 to 1998 (offspring cohort). The mean absolute interarm systolic blood pressure difference was 4.6 mm Hg (range 0-78). Increased interarm systolic blood pressure difference was present in 317 (9.4%) participants. The median follow-up time was 13.3 years, during which time 598 participants (17.6%) experienced a first cardiovascular event, including 83 (26.2%) participants with interarm systolic blood pressure difference ≥ 10 mm Hg. Compared with those with normal interarm systolic blood pressure difference, participants with an elevated interarm systolic blood pressure difference were older (63.0 years vs 60.9 years), had a greater prevalence of diabetes mellitus (13.3% vs 7.5%,), higher systolic blood pressure (136.3 mm Hg vs 129.3 mm Hg), and a higher total cholesterol

The Systolic Blood Pressure Difference Between Arms and Cardiovascular Disease in the Framingham Heart Study

PubMed Central

Weinberg, Ido; Gona, Philimon; O’Donnell, Christopher J.; Jaff, Michael R.; Murabito, Joanne M.

2014-01-01

Background An increased inter-arm systolic blood pressure difference is an easily determined physical examination finding. The relationship between inter-arm systolic blood pressure difference and risk of future cardiovascular disease is uncertain. We described the prevalence and risk factor correlates of inter-arm systolic blood pressure difference in the Framingham Heart Study (FHS) original and offspring cohorts and examined the association between inter-arm systolic blood pressure difference and incident cardiovascular disease and all-cause mortality. Methods An increased inter-arm systolic blood pressure difference was defined as ≥10mmHg using the average of initial and repeat blood pressure measurements obtained in both arms. Participants were followed through 2010 for incident cardiovascular disease events. Multivariable Cox proportional hazards regression analyses were performed to investigate the effect of inter-arm systolic blood pressure difference on incident cardiovascular disease. Results We examined 3,390 (56.3% female) participants aged 40 years and older, free of cardiovascular disease at baseline, mean age of 61.1 years, who attended a FHS examination between 1991 and 1994 (original cohort) and from 1995 to 1998 (offspring cohort). The mean absolute inter-arm systolic blood pressure difference was 4.6 mmHg (range 0 to 78). Increased inter-arm systolic blood pressure difference was present in 317 (9.4%) participants. The median follow-up time was 13.3 years, during which time 598 participants (17.6%) experienced a first cardiovascular event including 83 (26.2%) participants with inter-arm systolic blood pressure difference ≥10 mmHg. Compared to those with normal inter-arm systolic blood pressure difference, participants with an elevated inter-arm systolic blood pressure difference were older (63.0 years vs. 60.9 years), had a greater prevalence of diabetes mellitus (13.3% vs. 7.5%,), higher systolic blood pressure (136.3 mmHg vs. 129.3 mm

3D-printed poly(vinylidene fluoride)/carbon nanotube composites as a tunable, low-cost chemical vapour sensing platform

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

Kennedy, Z. C.; Christ, J. F.; Evans, K. A.

We report the production of flexible, highly-conductive poly(vinylidene flouride) (PVDF) and multi-walled carbon nanotube (MWCNT) composites as filament feedstock for 3D-printing. This account further describes, for the first-time, fused deposition modelling (FDM) derived 3D-printed objects with chemiresistive properties in response to volatile organic compounds. The typically prohibitive thermal expansion and die swell characteristics of PVDF were minimized by the presence of MWCNTs in the composites enabling straightforward processing and printing. The nanotubes form a dispersed network as characterized by helium ion microscopy, contributing to excellent conductivity (1 x 10-2 S / cm). The printed composites contain little residual metal particulatemore » relative to parts from commercial PLA-nanocomposite material visualized by micro X-ray computed tomography (μ-CT) and corroborated with thermogravimetric analysis. Printed sensing strips, with MWCNT loadings up to 15 % mass, function as reversible vapour sensors with the strongest responses arising with organic compounds capable of readily intercalating, and subsequently swelling the PVDF matrix (acetone and ethyl acetate). A direct correlation between MWCNT concentration and resistance change was also observed, with larger responses (up to 161 % after 3 minutes) generated with decreased MWCNT loadings. These findings highlight the utility of FDM printing in generating low-cost sensors that respond strongly and reproducibly to target vapours. Furthermore, the sensors can be easily printed in different geometries, expanding their utility to wearable form factors. The proposed formulation strategy may be tailored to sense diverse sets of vapour classes through structural modification of the polymer backbone and/or functionalization of the nanotubes within the composite.« less

Legal requirements and guidelines for the control of harmful laser generated particles, vapours and gases

NASA Astrophysics Data System (ADS)

Horsey, John

2015-07-01

This paper is a review of the Health and Safety laws and guidelines relating to laser generated emissions into the workplace and outside environment with emphasis on the differences between legal requirements and guideline advice. The types and nature of contaminants released by various laser processes (i.e. cutting, coding, engraving, marking etc) are discussed, together with the best methods for controlling them to within legal exposure limits. A brief description of the main extract air filtration techniques, including the principles of particulate removal and the action of activated carbon for gas/vapour/odour filtration, is given.

Female reproductive health in two lamp factories: effects of exposure to inorganic mercury vapour and stress factors.

PubMed

De Rosis, F; Anastasio, S P; Selvaggi, L; Beltrame, A; Moriani, G

1985-07-01

To evaluate the possible influence of mercury vapour on female reproduction, 153 women working in a mercury vapour lamp factory have been compared with 193 women employed in another factory of the same company, where mercury was not used. Both groups of subjects were exposed to stress factors (noise, rhythms of production, and shift work). The production process has been analysed by inspection of the plants and by collective discussions with "homogeneous groups" of workers; a retrospective inquiry into work history and reproductive health events has been subsequently performed by an individual interview. Women exposed to mercury vapour currently not exceeding the time weighted average air concentration of 0.01 mg/m3 declared higher prevalence and incidence rates of menstrual disorders, primary subfecundity, and adverse pregnancy outcome; however, the progression of these problems with the level of exposure to mercury inside the same factory was not always clear. The results of this study neither prove nor exclude the possibility that occupational exposure to this concentration of mercury has a negative effect on female reproduction.

Inter-arm blood pressure difference in type 2 diabetes: a barrier to effective management?

PubMed Central

Clark, Christopher E; Greaves, Colin J; Evans, Philip H; Dickens, Andy; Campbell, John L

2009-01-01

Background Previous studies have identified a substantial prevalence of a blood pressure difference between arms in various populations, but not patients with type 2 diabetes. Recognition of such a difference would be important as a potential cause of underestimation of blood pressure. Aim To measure prevalence of an inter-arm blood pressure difference in patients with type 2 diabetes, and to estimate how frequently blood pressure measurements could be erroneously underestimated if an inter-arm difference is unrecognised. Design of study Cross-sectional study. Setting Five surgeries covered by three general practices, Devon, England. Method Patients with type 2 diabetes underwent bilateral simultaneous blood pressure measurements using a validated protocol. Mean blood pressures were calculated for each arm to derive mean systolic and diastolic differences, and to estimate point prevalence of predefined magnitudes of difference. Results A total of 101 participants were recruited. Mean age was 66 years (standard deviation [SD] = 13.9 years); 59% were male, and mean blood pressure was 138/79 mmHg (SD = 15/10 mmHg). Ten participants (10%; 95% confidence interval [CI] = 4 to 16) had a systolic inter-arm difference ≥10 mmHg; 29 (29%; 95% CI = 20 to 38) had a diastolic difference ≥5 mmHg; and three (3%; 95% CI = 0 to 6) a diastolic difference ≥10 mmHg. No confounding variable was observed to account for the magnitude of an inter-arm difference. Conclusion A systolic inter-arm difference ≥10 mmHg was observed in 10% of patients with diabetes. Failure to recognise this would misclassify half of these as normotensive rather than hypertensive using the lower-reading arm. New patients with type 2 diabetes should be screened for an inter-arm blood pressure difference. PMID:19520026

Structural and environmental dependence of superlow friction in ion vapour-deposited a-C : H : Si films for solid lubrication application

NASA Astrophysics Data System (ADS)

Chen, Xinchun; Kato, Takahisa; Kawaguchi, Masahiro; Nosaka, Masataka; Choi, Junho

2013-06-01

Understanding the tribochemical interaction of water molecules in humid environment with carbonaceous film surfaces, especially hydrophilic surface, is fundamental for applications in tribology and solid lubrication. This paper highlights some experimental evidence to elucidate the structural and environmental dependence of ultralow or even superlow friction in ion vapour-deposited a-C : H : Si films. The results indicate that both surface density of silicon hydroxyl group (Si-OH) and humidity level (RH) determine the frictional performance of a-C : H : Si films. Ultralow friction coefficient μ (˜0.01-0.055) is feasible in a wide range of RH. The dissociative formation of hydrophilic Si-OH surface and the following nanostructure of interfacial water molecules under contact pressure are the origin of ultralow friction for a-C : H : Si films in humid environment. The correlation between contact pressure and friction coefficient derived from Hertzian contact model is not valid in the present case. Under this nanoscale boundary lubrication, the friction coefficient tends to increase as the contact pressure increases. There even exists a contact pressure threshold for the transition from ultralow to superlow friction (μ ˜ 0.007). In comparison, when tribotested in dry N2, the observed superlow friction (μ ˜ 0.004) in the absence of water is correlated with the formation of a low shear strength tribolayer by wear-induced phase transformation.

Non-invasive pressure difference estimation from PC-MRI using the work-energy equation

PubMed Central

Donati, Fabrizio; Figueroa, C. Alberto; Smith, Nicolas P.; Lamata, Pablo; Nordsletten, David A.

2015-01-01

Pressure difference is an accepted clinical biomarker for cardiovascular disease conditions such as aortic coarctation. Currently, measurements of pressure differences in the clinic rely on invasive techniques (catheterization), prompting development of non-invasive estimates based on blood flow. In this work, we propose a non-invasive estimation procedure deriving pressure difference from the work-energy equation for a Newtonian fluid. Spatial and temporal convergence is demonstrated on in silico Phase Contrast Magnetic Resonance Image (PC-MRI) phantoms with steady and transient flow fields. The method is also tested on an image dataset generated in silico from a 3D patient-specific Computational Fluid Dynamics (CFD) simulation and finally evaluated on a cohort of 9 subjects. The performance is compared to existing approaches based on steady and unsteady Bernoulli formulations as well as the pressure Poisson equation. The new technique shows good accuracy, robustness to noise, and robustness to the image segmentation process, illustrating the potential of this approach for non-invasive pressure difference estimation. PMID:26409245

Evaporation of freely suspended single droplets: experimental, theoretical and computational simulations

NASA Astrophysics Data System (ADS)

Hołyst, R.; Litniewski, M.; Jakubczyk, D.; Kolwas, K.; Kolwas, M.; Kowalski, K.; Migacz, S.; Palesa, S.; Zientara, M.

2013-03-01

Evaporation is ubiquitous in nature. This process influences the climate, the formation of clouds, transpiration in plants, the survival of arctic organisms, the efficiency of car engines, the structure of dried materials and many other phenomena. Recent experiments discovered two novel mechanisms accompanying evaporation: temperature discontinuity at the liquid-vapour interface during evaporation and equilibration of pressures in the whole system during evaporation. None of these effects has been predicted previously by existing theories despite the fact that after 130 years of investigation the theory of evaporation was believed to be mature. These two effects call for reanalysis of existing experimental data and such is the goal of this review. In this article we analyse the experimental and the computational simulation data on the droplet evaporation of several different systems: water into its own vapour, water into the air, diethylene glycol into nitrogen and argon into its own vapour. We show that the temperature discontinuity at the liquid-vapour interface discovered by Fang and Ward (1999 Phys. Rev. E 59 417-28) is a rule rather than an exception. We show in computer simulations for a single-component system (argon) that this discontinuity is due to the constraint of momentum/pressure equilibrium during evaporation. For high vapour pressure the temperature is continuous across the liquid-vapour interface, while for small vapour pressures the temperature is discontinuous. The temperature jump at the interface is inversely proportional to the vapour density close to the interface. We have also found that all analysed data are described by the following equation: da/dt = P1/(a + P2), where a is the radius of the evaporating droplet, t is time and P1 and P2 are two parameters. P1 = -λΔT/(qeffρL), where λ is the thermal conductivity coefficient in the vapour at the interface, ΔT is the temperature difference between the liquid droplet and the vapour far

Evaluating the virucidal efficacy of hydrogen peroxide vapour.

PubMed

Goyal, S M; Chander, Y; Yezli, S; Otter, J A

2014-04-01

Surface contamination has been implicated in the transmission of certain viruses, and surface disinfection can be an effective measure to interrupt the spread of these agents. To evaluate the in-vitro efficacy of hydrogen peroxide vapour (HPV), a vapour-phase disinfection method, for the inactivation of a number of structurally distinct viruses of importance in the healthcare, veterinary and public sectors. The viruses studied were: feline calicivirus (FCV, a norovirus surrogate); human adenovirus type 1; transmissible gastroenteritis coronavirus of pigs (TGEV, a severe acute respiratory syndrome coronavirus [SARS-CoV] surrogate); avian influenza virus (AIV); and swine influenza virus (SwIV). The viruses were dried on stainless steel discs in 20- or 40-μL aliquots and exposed to HPV produced by a Clarus L generator (Bioquell, Horsham, PA, USA) in a 0.2-m(3) environmental chamber. Three vaporized volumes of hydrogen peroxide were tested in triplicate for each virus: 25, 27 and 33 mL. No viable viruses were identified after HPV exposure at any of the vaporized volumes tested. HPV was virucidal (>4-log reduction) against FCV, adenovirus, TGEV and AIV at the lowest vaporized volume tested (25 mL). For SwIV, due to low virus titre on the control discs, >3.8-log reduction was shown for the 25-mL vaporized volume and >4-log reduction was shown for the 27-mL and 33-mL vaporized volumes. HPV was virucidal for structurally distinct viruses dried on surfaces, suggesting that HPV can be considered for the disinfection of virus-contaminated surfaces. Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Insole-pressure distribution for normal children in different age groups.

PubMed

Liu, Xue-Cheng; Lyon, Roger; Thometz, John G; Curtin, Brian; Tarima, Serge; Tassone, Channing

2011-09-01

In measuring plantar pressures during gait, earlier methods have used a platform system that does not take into account the interactions feet have with orthotics and shoe wearing. The purpose of the study was to provide normal insole plantar pressure parameter data during stance phase using the Pedar pressure insole system. Twenty-nine normal children, age 6 to 16 years, were recruited and walked along the 25 m walkway at self-selected speeds. Patients were divided into 2 separate groups for statistical analysis--juniors (< 12 y old) and teenagers (> 13 y old). The pressure map was divided into 8 regions (masks) determined by anatomic landmarks and a total of 7 pressure parameters were analyzed of each mask. We did not detect significant differences in foot pressures between juniors and teenagers when regarding sex, or left and right feet for 7 parameters measured. This normative data will provide a basis with which to more accurately assess pediatric pathologic foot deformities and to distinguish dynamic foot deformities from anatomic foot deformities. THE LEVEL OF EVIDENCE: Level II.

Transport mechanisms through PE-CVD coatings: influence of temperature, coating properties and defects on permeation of water vapour

NASA Astrophysics Data System (ADS)

Kirchheim, Dennis; Jaritz, Montgomery; Mitschker, Felix; Gebhard, Maximilian; Brochhagen, Markus; Hopmann, Christian; Böke, Marc; Devi, Anjana; Awakowicz, Peter; Dahlmann, Rainer

2017-03-01

Gas transport mechanisms through plastics are usually described by the temperature-dependent Arrhenius-model and compositions of several plastic layers are represented by the CLT. When it comes to thin films such as plasma-enhanced chemical vapour deposition (PE-CVD) or plasma-enhanced atomic layer deposition (PE-ALD) coatings on substrates of polymeric material, a universal model is lacking. While existing models describe diffusion through defects, these models presume that permeation does not occur by other means of transport mechanisms. This paper correlates the existing transport models with data from water vapour transmission experiments.

Kinetics of the reaction between nitrogen dioxide and water vapour

NASA Astrophysics Data System (ADS)

Svensson, R.; Ljungström, E.; Lindqvist, O.

The rate of disappearance of nitrogen dioxide (NO 2) with water vapour and formation of nitrous acid (HONO) in the dark has been investigated in batch experiments. IR spectroscopy was used to determine the concentrations of NO 2, HONO and NO. The reaction is first order both with respect to NO 2 and water vapour and proceeds heterogenously on most unpoisoned surfaces. Initially, the amount of HONO formed is close to half the NO 2 which has disappeared. When the surface in the present reactor (surface to volume ratio = 14 m -1) has reached its limiting state of poisoning, the reaction is still active and the NO 2 disappearance follows the expression: -d[NO 2] /dt = 2k 1[NO 2] [H 2O] where k1 = 4.1 (± 0.8) 10 -8 ppm -1 min -1 (22°C). The S/V ratio dependence of the rate shows that a heterogenous reaction proceeds but the existing evidence is not conclusive about a possible homogenous contribution to the remaining activity. A rate expression which describes the overall reaction at temperatures around 25°C, when the surface present is made passive, is: -d[NO 2] /dt = ( S/V5.6(±0.9)10 -9 + 2.3(±6.5)10 -9)[NO 2][H 2O] .

Atomic fluorescence emitted from a corona discharge in helium above and below saturated vapour pressure

NASA Astrophysics Data System (ADS)

Shiltagh, Nagham M.; Mendoza Luna, Luis G.; Watkins, Mark J.; Thornton, Stuart C.; von Haeften, Klaus

2018-01-01

A new apparatus was constructed to investigate the visible and near infrared fluorescence spectroscopy of electronically excited helium over a wide range of pressures and temperatures, covering both the gaseous and liquid phases. To achieve sufficient throughput, increased sensitivity was established by employing a micro-discharge cell and a high performance lens system that allows for a large collection solid angle. With this set-up, several thousand spectra were recorded. The atomic 3 s 1 S → 2 p 1 P and 3 s 3 S → 2 p 3 P atomic transitions showed line shifts, spectral broadening and intensity changes that were dependent in magnitude on pressure, temperature and thermodynamic phase. While in the gas phase the lines showed little dependency on the discharge cell temperature, the opposite was observed for the liquid phase, suggesting that a significant number of atoms were solvated. Triplet lines were up to a factor of 50 times stronger in intensity than the singlet lines, depending on pressure. When taking the particle density into account, this effect was stronger in the gas phase than in the liquid phase of helium. This was attributed to the recombination of He2 +, He3 + and He4 + with electrons, which is facilitated in the gas phase because of the significantly higher mobility.

Using a case-mix-adjusted pressure sore incidence study in a surgical directorate to improve patient outcomes in pressure ulcer prevention.

PubMed

Watret, L

1999-10-01

The Glasgow Acute Clinical Audit Sub-Committee on Pressure Sores has previously carried out studies of incidence of pressure ulcers in the medical directorates and case-mix-adjusted the figures for length of hospital stay and risk assessment score. Case-mix classification is 'classification of people or treatment placed into groups using characteristics associated with condition, treatment or outcome that can be used to predict need, resource, use of outcomes'. In this instance, crude pressure ulcer incidence figures may be adjusted for length of hospital stay and pressure sore risk assessment score, and stratified into groups, which allows like to be compared with like. The value in case-mix-adjusted figures lies in repeating the exercise, thus determining the trend for individual areas and assessing whether improvement in the quality of care is being achieved. This is more positive than creation of 'league tables' comparing simultaneous studies in a number of areas. The figures showed that there was no statistically significant difference between surgical directorates in trusts with regard to risk assessment scores and length of hospital stay. Gathering data on the incidence of pressure ulcer development allows us to identify where new sores are occurring, but does not critically analyse the nursing intervention taken in individual cases, which identifies preventive strategies. The Glasgow group's primary aim was to gather data on case-mix-adjusted incidence of pressure damage; the secondary objectives were to scrutinize the data to gather more general information on intrinsic and extrinsic factors which may predispose to pressure ulcer development. The study was carried out in the surgical directorate. Findings showed that incidence was low (1.1%), with the majority of sores being superficial. There was a correlation between pressure ulcer development and incontinence, evidence of under-utilization of moving and handling aids for prevention of pressure ulcers

Microcirculatory responses of sacral tissue in healthy individuals and inpatients on different pressure-redistribution mattresses.

PubMed

Bergstrand, S; Källman, U; Ek, A-C; Engström, M; Lindgren, M

2015-08-01

The aim of this study was to explore the interaction between interface pressure, pressure-induced vasodilation, and reactive hyperaemia with different pressure-redistribution mattresses. A cross-sectional study was performed with a convenience sample of healthy young individuals, and healthy older individuals and inpatients, at a university hospital in Sweden. Blood flow was measured at depths of 1mm, 2mm, and 10mm using laser Doppler flowmetry and photoplethysmography. The blood flow, interface pressure and skin temperature were measured in the sacral tissue before, during, and after load while lying on one standard hospital mattress and three different pressure-redistribution mattresses. There were significant differences between the average sacral pressure, peak sacral pressure, and local probe pressure on the three pressure-redistribution mattresses, the lowest values found were with the visco-elastic foam/air mattress (23.5 ± 2.5mmHg, 49.3 ± 11.1mmHg, 29.2 ± 14.0mmHg, respectively). Blood flow, measured as pressure-induced vasodilation, was most affected in the visco-elastic foam/air group compared to the alternating pressure mattress group at tissue depths of 2mm (39.0% and 20.0%, respectively), and 10mm (56.9 % and 35.1%, respectively). Subjects in all three groups, including healthy 18-65 year olds, were identified with no pressure-induced vasodilation or reactive hyperaemia on any mattress (n=11), which is considered a high-risk blood flow response. Interface pressure magnitudes considered not harmful during pressure-exposure on different pressure-redistribution mattresses can affect the microcirculation in different tissue structures. Despite having the lowest pressure values compared with the other mattresses, the visco-elastic foam/air mattress had the highest proportion of subjects with decreased blood flow. Healthy young individuals were identified with the high-risk blood flow response, suggesting an innate vulnerability to pressure exposure

The difference in blood pressure readings between arms and survival: primary care cohort study.

PubMed

Clark, Christopher E; Taylor, Rod S; Shore, Angela C; Campbell, John L

2012-03-20

To determine whether a difference in systolic blood pressure readings between arms can predict a reduced event free survival after 10 years. Cohort study. Rural general practice in Devon, United Kingdom. 230 people receiving treatment for hypertension in primary care. Bilateral blood pressure measurements recorded at three successive surgery attendances. Cardiovascular events and deaths from all causes during a median follow-up of 9.8 years. At recruitment 24% (55/230) of participants had a mean interarm difference in systolic blood pressure of 10 mm Hg or more and 9% (21/230) of 15 mm Hg or more; these differences were associated with an increased risk of all cause mortality (adjusted hazard ratio 3.6, 95% confidence interval 2.0 to 6.5 and 3.1, 1.6 to 6.0, respectively). The risk of death was also increased in 183 participants without pre-existing cardiovascular disease with an interarm difference in systolic blood pressure of 10 mm Hg or more or 15 mm Hg or more (2.6, 1.4 to 4.8 and 2.7, 1.3 to 5.4). An interarm difference in diastolic blood pressure of 10 mm Hg or more was weakly associated with an increased risk of cardiovascular events or death. Differences in systolic blood pressure between arms can predict an increased risk of cardiovascular events and all cause mortality over 10 years in people with hypertension. This difference could be a valuable indicator of increased cardiovascular risk. Bilateral blood pressure measurements should become a routine part of cardiovascular assessment in primary care.

[Features of arterial blood pressure in elderly persons of different ethnic groups in Yakutsk].

PubMed

Nikitin, Iu P; Tatarinova, O V; Neustroeva, V N; Shcherbakova, L V; Sidorov, A S

2013-01-01

The differences in arterial blood pressure in the sample of population in the age of 60 and older of different ethnic groups in Yakutsk, as well as its connection with the other cardiovascular diseases risk factors have been analyzed. It was shown that the average values of systolic and diastolic blood pressure in subsample of the Yakuts appeared to be lower than in Caucasoid gerontic persons. The average values of systolic arterial blood pressure both in the Yakuts and in the Caucasoids were detected higher than normal values in all age-dependent subgroups. The average values of diastolic blood pressure in both ethnic groups were within the limits of high normal level. From 60 to 90 years and older the decrease in systolic and diastolic arterial blood pressure was detected; it was more marked in Caucasoid gerontic persons. The average values of pulse pressure in the Yakuts and in the Caucasoids appeared to be higher than the existing standard and didn't have any differences in ethnic groups. In both ethnical subsamples, pulse pressure values increase was observed in persons of 60-89 years old and its decrease after 90. Persons with overweight, obesity, central (abdominal) obesity, dyslypoproteidemias irrespective of belonging to ethnical group were characterized as having higher levels of arterial blood pressure. Statistically significant differences in the levels of arterial blood pressure in the Yakuts and in the Caucasoids depending on hyperglycemia, smoking, the presence of burdened anamnesis, educational level, marital status was not detected.

Synthesis of Ordered Mesoporous Phenanthrenequinone-Carbon via π-π Interaction-Dependent Vapor Pressure for Rechargeable Batteries

PubMed Central

Kwon, Mi-Sook; Choi, Aram; Park, Yuwon; Cheon, Jae Yeong; Kang, Hyojin; Jo, Yong Nam; Kim, Young-Jun; Hong, Sung You; Joo, Sang Hoon; Yang, Changduk; Lee, Kyu Tae

2014-01-01

The π-π interaction-dependent vapour pressure of phenanthrenequinone can be used to synthesize a phenanthrenequinone-confined ordered mesoporous carbon. Intimate contact between the insulating phenanthrenequinone and the conductive carbon framework improves the electrical conductivity. This enables a more complete redox reaction take place. The confinement of the phenanthrenequinone in the mesoporous carbon mitigates the diffusion of the dissolved phenanthrenequinone out of the mesoporous carbon, and improves cycling performance. PMID:25490893

Impact of water vapour and carbon dioxide on surface composition of C{sub 3}A polymorphs studied by X-ray photoelectron spectroscopy

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

Dubina, E.; Plank, J.; Black, L., E-mail: l.black@leeds.ac.uk

2015-07-15

The surface specific analytical method, X-ray photoelectron spectroscopy (XPS), has been used to study the effects of water vapour and CO{sub 2} on the cubic and orthorhombic polymorphs of C{sub 3}A. Significant differences between the two polymorphs were observed in the XPS spectra. Upon exposure to water vapour, both polymorphs produced C{sub 4}AH{sub 13} on their surfaces. Additionally, the sodium-doped o-C{sub 3}A developed NaOH and traces of C{sub 3}AH{sub 6} on its surface. Subsequent carbonation yielded mono carboaluminate on both polymorphs. Large amounts of Na{sub 2}CO{sub 3} also formed on the surface of o-C{sub 3}A as a result of carbonationmore » of NaOH. Furthermore, the extent of carbonation was much more pronounced for o-C{sub 3}A{sub o} than for c-C{sub 3}A.« less

Simultaneously Measured Interarm Blood Pressure Difference and Stroke: An Individual Participants Data Meta-Analysis.

PubMed

Tomiyama, Hirofumi; Ohkuma, Toshiaki; Ninomiya, Toshiharu; Mastumoto, Chisa; Kario, Kazuomi; Hoshide, Satoshi; Kita, Yoshikuni; Inoguchi, Toyoshi; Maeda, Yasutaka; Kohara, Katsuhiko; Tabara, Yasuharu; Nakamura, Motoyuki; Ohkubo, Takayoshi; Watada, Hirotaka; Munakata, Masanori; Ohishi, Mitsuru; Ito, Norihisa; Nakamura, Michinari; Shoji, Tetsuo; Vlachopoulos, Charalambos; Yamashina, Akira

2018-06-01

We conducted individual participant data meta-analysis to examine the validity of interarm blood pressure difference in simultaneous measurement as a marker to identify subjects with ankle-brachial pressure index <0.90 and to predict future cardiovascular events. We collected individual participant data on 13 317 Japanese subjects from 10 cohorts (general population-based cohorts, cohorts of patients with past history of cardiovascular events, and those with cardiovascular risk factors). Binary logistic regression analysis with adjustments identified interarm blood pressure difference >5 mm Hg as being associated with a significant odds ratio for the presence of ankle-brachial pressure index <0.90 (odds ratio, 2.19; 95% confidence interval, 1.60-3.03; P <0.01). Among 11 726 subjects without a past history of cardiovascular disease, 249 developed stroke during the average follow-up period of 7.4 years. Interarm blood pressure difference >15 mm Hg was associated with a significant Cox stratified adjusted hazard ratio for subsequent stroke (hazard ratio, 2.42; 95% confidence interval, 1.27-4.60; P <0.01). Therefore, interarm blood pressure differences, measured simultaneously in both arms, may be associated with vascular damage in the systemic arterial tree. These differences may be useful for identifying subjects with an ankle-brachial pressure index of <0.90 in the overall study population, and also a reliable predictor of future stroke in subjects without a past history of cardiovascular disease. These findings support the recommendation to measure blood pressure in both arms at the first visit. © 2018 American Heart Association, Inc.

The vulvar skin microenvironment: influence of different panty liners on temperature, pH and microflora.

PubMed

Runeman, Bo; Rybo, Göran; Forsgren-Brusk, Ulla; Larkö, Olle; Larsson, Peter; Faergemann, Jan

2004-01-01

The aim of this study was to confirm findings that vapour-impermeable panty liners might impair skin climate, and to assess their impact on the skin microflora. Temperature, surface pH and aerobic microflora were measured on vulvar skin of 102 women. The mean skin temperature was 1.1 degrees C higher when using a vapour-impermeable panty liner compared with not using one. Use of panty liners with vapour-permeable back sheets and acidic cores resulted in skin temperature, pH and microflora levels that were very close to those observed in persons not using liners. The temperature, pH and total number of microorganisms were significantly lower for users of vapour-permeable panty liners than for users of vapour-impermeable ones (p <0.05, p<0.001 and p<0.001, respectively). The microorganism densities were usually higher when using the vapour-impermeable panty liner, but mean differences were minor. The use of panty liners seems not to imply a microbial risk for normal, healthy women.

GPS Tomography: Water Vapour Monitoring for Germany

NASA Astrophysics Data System (ADS)

Bender, Michael; Dick, Galina; Wickert, Jens; Raabe, Armin

2010-05-01

Ground based GPS atmosphere sounding provides numerous atmospheric quantities with a high temporal resolution for all weather conditions. The spatial resolution of the GPS observations is mainly given by the number of GNSS satellites and GPS ground stations. The latter could considerably be increased in the last few years leading to more reliable and better resolved GPS products. New techniques such as the GPS water vapour tomography gain increased significance as data from large and dense GPS networks become available. The GPS tomography has the potential to provide spatially resolved fields of different quantities operationally, i. e. the humidity or wet refractivity as required for meteorological applications or the refraction index which is important for several space based observations or for precise positioning. The number of German GPS stations operationally processed by the GFZ in Potsdam was recently enlarged to more than 300. About 28000 IWV observations and more than 1.4 millions of slant total delay data are now available per day with a temporal resolution of 15 min and 2.5 min, respectively. The extended network leads not only to a higher spatial resolution of the tomographically reconstructed 3D fields but also to a much higher stability of the inversion process and with that to an increased quality of the results. Under these improved conditions the GPS tomography can operate continuously over several days or weeks without applying too tight constraints. Time series of tomographically reconstructed humidity fields will be shown and different initialisation strategies will be discussed: Initialisation with a simple exponential profile, with a 3D humidity field extrapolated from synoptic observations and with the result of the preceeding reconstruction. The results are compared to tomographic reconstructions initialised with COSMO-DE analyses and to the corresponding model fields. The inversion can be further stabilised by making use of independent

Field Evaluation of Polymer Capacitive Humidity Sensors for Bowen Ratio Energy Balance Flux Measurements

PubMed Central

Savage, Michael J.

2010-01-01

The possibility of reliable, reasonably accurate and relatively inexpensive estimates of sensible heat and latent energy fluxes was investigated using a commercial combination thin-film polymer capacitive relative humidity and adjacent temperature sensor instrument. Long-term and unattended water vapour pressure profile difference measurements using low-power combination instruments were compared with those from a cooled dewpoint mirror hygrometer, the latter often used with Bowen ratio energy balance (BREB) systems. An error analysis, based on instrument relative humidity and temperature errors, was applied for various capacitive humidity instrument models. The main disadvantage of a combination capacitive humidity instrument is that two measurements, relative humidity and temperature, are required for estimation of water vapour pressure as opposed to one for a dewpoint hygrometer. In a laboratory experiment using an automated procedure, water vapour pressure differences generated using a reference dewpoint generator were measured using a commercial model (Dew-10) dewpoint hygrometer and a combination capacitive humidity instrument. The laboratory measurement comparisons showed that, potentially, an inexpensive model combination capacitive humidity instrument (CS500 or HMP50), or for improved results a slightly more expensive model (HMP35C or HMP45C), could substitute for the more expensive dewpoint hygrometer. In a field study, in a mesic grassland, the water vapour pressure measurement noise for the combination capacitive humidity instruments was greater than that for the dewpoint hygrometer. The average water vapour pressure profile difference measured using a HMP45C was highly correlated with that from a dewpoint hygrometer with a slope less than unity. Water vapour pressure measurements using the capacitive humidity instruments were not as accurate, compared to those obtained using a dewpoint hygrometer, but the resolution magnitudes for the profile

Continuous measurements of stable isotopes of carbon dioxide and water vapour in an urban atmosphere: isotopic variations associated with meteorological conditions.

PubMed

Wada, Ryuichi; Matsumi, Yutaka; Nakayama, Tomoki; Hiyama, Tetsuya; Fujiyoshi, Yasushi; Kurita, Naoyuki; Muramoto, Kenichiro; Takanashi, Satoru; Kodama, Naomi; Takahashi, Yoshiyuki

2017-12-01

Isotope ratios of carbon dioxide and water vapour in the near-surface air were continuously measured for one month in an urban area of the city of Nagoya in central Japan in September 2010 using laser spectroscopic techniques. During the passages of a typhoon and a stationary front in the observation period, remarkable changes in the isotope ratios of CO 2 and water vapour were observed. The isotope ratios of both CO 2 and water vapour decreased during the typhoon passage. The decreases can be attributed to the air coming from an industrial area and the rainout effects of the typhoon, respectively. During the passage of the stationary front, δ 13 C-CO 2 and δ 18 O-CO 2 increased, while δ 2 H-H 2 Ov and δ 18 O-H 2 Ov decreased. These changes can be attributed to the air coming from rural areas and the air surrounding the observational site changing from a subtropical air mass to a subpolar air mass during the passage of the stationary front. A clear relationship was observed between the isotopic CO 2 and water vapour and the meteorological phenomena. Therefore, isotopic information of CO 2 and H 2 Ov could be used as a tracer of meteorological information.

The difference in blood pressure readings between arms and survival: primary care cohort study

PubMed Central

Taylor, Rod S; Shore, Angela C; Campbell, John L

2012-01-01

Objective To determine whether a difference in systolic blood pressure readings between arms can predict a reduced event free survival after 10 years. Design Cohort study. Setting Rural general practice in Devon, United Kingdom. Participants 230 people receiving treatment for hypertension in primary care. Intervention Bilateral blood pressure measurements recorded at three successive surgery attendances. Main outcome measures Cardiovascular events and deaths from all causes during a median follow-up of 9.8 years. Results At recruitment 24% (55/230) of participants had a mean interarm difference in systolic blood pressure of 10 mm Hg or more and 9% (21/230) of 15 mm Hg or more; these differences were associated with an increased risk of all cause mortality (adjusted hazard ratio 3.6, 95% confidence interval 2.0 to 6.5 and 3.1, 1.6 to 6.0, respectively). The risk of death was also increased in 183 participants without pre-existing cardiovascular disease with an interarm difference in systolic blood pressure of 10 mm Hg or more or 15 mm Hg or more (2.6, 1.4 to 4.8 and 2.7, 1.3 to 5.4). An interarm difference in diastolic blood pressure of 10 mm Hg or more was weakly associated with an increased risk of cardiovascular events or death. Conclusions Differences in systolic blood pressure between arms can predict an increased risk of cardiovascular events and all cause mortality over 10 years in people with hypertension. This difference could be a valuable indicator of increased cardiovascular risk. Bilateral blood pressure measurements should become a routine part of cardiovascular assessment in primary care. PMID:22433975

Airborne and satellite remote sensing of the mid-infrared water vapour continuum.

PubMed

Newman, Stuart M; Green, Paul D; Ptashnik, Igor V; Gardiner, Tom D; Coleman, Marc D; McPheat, Robert A; Smith, Kevin M

2012-06-13

Remote sensing of the atmosphere from space plays an increasingly important role in weather forecasting. Exploiting observations from the latest generation of weather satellites relies on an accurate knowledge of fundamental spectroscopy, including the water vapour continuum absorption. Field campaigns involving the Facility for Airborne Atmospheric Measurements research aircraft have collected a comprehensive dataset, comprising remotely sensed infrared radiance observations collocated with accurate measurements of the temperature and humidity structure of the atmosphere. These field measurements have been used to validate the strength of the infrared water vapour continuum in comparison with the latest laboratory measurements. The recent substantial changes to self-continuum coefficients in the widely used MT_CKD (Mlawer-Tobin-Clough-Kneizys-Davies) model between 2400 and 3200 cm(-1) are shown to be appropriate and in agreement with field measurements. Results for the foreign continuum in the 1300-2000 cm(-1) band suggest a weak temperature dependence that is not currently included in atmospheric models. A one-dimensional variational retrieval experiment is performed that shows a small positive benefit from using new laboratory-derived continuum coefficients for humidity retrievals.

Localized sources of water vapour on the dwarf planet (1) Ceres.

PubMed

Küppers, Michael; O'Rourke, Laurence; Bockelée-Morvan, Dominique; Zakharov, Vladimir; Lee, Seungwon; von Allmen, Paul; Carry, Benoît; Teyssier, David; Marston, Anthony; Müller, Thomas; Crovisier, Jacques; Barucci, M Antonietta; Moreno, Raphael

2014-01-23

The 'snowline' conventionally divides Solar System objects into dry bodies, ranging out to the main asteroid belt, and icy bodies beyond the belt. Models suggest that some of the icy bodies may have migrated into the asteroid belt. Recent observations indicate the presence of water ice on the surface of some asteroids, with sublimation a potential reason for the dust activity observed on others. Hydrated minerals have been found on the surface of the largest object in the asteroid belt, the dwarf planet (1) Ceres, which is thought to be differentiated into a silicate core with an icy mantle. The presence of water vapour around Ceres was suggested by a marginal detection of the photodissociation product of water, hydroxyl (ref. 12), but could not be confirmed by later, more sensitive observations. Here we report the detection of water vapour around Ceres, with at least 10(26) molecules being produced per second, originating from localized sources that seem to be linked to mid-latitude regions on the surface. The water evaporation could be due to comet-like sublimation or to cryo-volcanism, in which volcanoes erupt volatiles such as water instead of molten rocks.

Hair analysis as a useful procedure for detection of vapour exposure to chemical warfare agents: simulation of sulphur mustard with methyl salicylate.

PubMed

Spiandore, Marie; Piram, Anne; Lacoste, Alexandre; Josse, Denis; Doumenq, Pierre

2014-06-01

Chemical warfare agents (CWA) are highly toxic compounds which have been produced to kill or hurt people during conflicts or terrorist attacks. Despite the fact that their use is strictly prohibited according to international convention, populations' exposure still recently occurred. Development of markers of exposure to CWA is necessary to distinguish exposed victims from unexposed ones. We present the first study of hair usage as passive sampler to assess contamination by chemicals in vapour form. This work presents more particularly the hair adsorption capacity for methyl salicylate used as a surrogate of the vesicant sulphur mustard. Chemical vapours toxicity through the respiratory route has historically been defined through Haber's law's concentration-time (Ct) product, and vapour exposure of hair to methyl salicylate was conducted with various times or doses of exposure in the range of incapacitating and lethal Ct products corresponding to sulphur mustard. Following exposure, extraction of methyl salicylate from hair was conducted by simple soaking in dichloromethane. Methyl salicylate could be detected on hair for vapour concentration corresponding to about one fifth of the sulphur mustard concentration that would kill 50% of exposed individuals (LCt50). The amount of methyl salicylate recovered from hair increased with time or dose of exposure. It showed a good correlation with the concentration-time product, suggesting that hair could be used like a passive sampler to assess vapour exposure to chemical compounds. It introduces great perspectives concerning the use of hair as a marker of exposure to CWA. Copyright © 2014 John Wiley & Sons, Ltd.

Inter-arm blood pressure differences compared with ambulatory monitoring: a manifestation of the 'white-coat' effect?

PubMed

Martin, Una; Holder, Roger; Hodgkinson, James; McManus, Richard

2013-02-01

Inter-arm difference in blood pressure of >10 mmHg is associated with peripheral vascular disease, but it is unclear how much of the difference in sequential right and left arm blood pressure measurements might be due to a 'white-coat' effect. To use ambulatory blood pressure monitoring (ABPM) to better understand the clinical significance of inter-arm differences in blood pressure. Retrospective study in a teaching hospital in Birmingham. Anonymised clinical data collected from 784 patients attending a single hospital-based hypertension clinic were retrospectively analysed. Each participant had blood pressure measured sequentially in both arms, followed by ABPM over the subsequent 24 hours. Data were available for 710 (91%) patients, of whom 39.3% (279) had a blood pressure difference of 10 mmHg or more between each arm. Compared to daytime systolic ABPM, the difference was 25.1 mmHg using the arm with the highest reading, but only 15.5 mmHg if the lower reading was taken (mean difference 9.6 mmHg (95% confidence interval [CI] = 9.0 mmHg to 10.3 mmHg)). However, differences between mean right (20.7 mmHg) or left (19.9 mmHg) arm blood pressure and daytime systolic ABPM were very similar. Compared with ABPM, use of the higher of the left and right arm readings measured sequentially appears to overestimate true mean blood pressure. As there is no significant difference in the extent of disparity with ABPM by left or right arm, this is unlikely to be due to arm dominance and may be due to the 'white-coat' effect reducing blood pressure on repeated measurement. Where a large inter-arm blood pressure difference is detected with sequential measurement, healthcare professionals should re-measure the blood pressure in the original arm.

Influence of the Pressure Difference and Door Swing on Heavy Contaminants Migration between Rooms

PubMed Central

Hendiger, Jacek; Chludzińska, Marta; Ziętek, Piotr

2016-01-01

This paper presents the results of investigations whose aim was to describe the influence of the pressure difference level on the ability of contaminants migration between neighbouring rooms in dynamic conditions associated with door swing. The analysis was based on airflow visualization made with cold smoke, which simulated the heavy contaminants. The test room was pressurized to a specific level and then the door was opened to observe the trail of the smoke plume in the plane of the door. The door was opened in both directions: to the positively and negatively pressurized room. This study focuses on the visualization of smoke plume discharge and an uncertainty analysis is not applicable. Unlike other studies which focus on the analysis of pressure difference, the present study looks at the contaminants which are heavier than air and on “pumping out” the contaminants by means of door swing. Setting the proper level of pressure difference between the contaminated room and the neighbouring rooms can prove instrumental in ensuring protection against toxic contaminants migration. This study helped to establish the threshold of pressure difference necessary to reduce migration of heavy contaminants to neighbouring rooms. PMID:27171260

Influence of the Pressure Difference and Door Swing on Heavy Contaminants Migration between Rooms.

PubMed

Hendiger, Jacek; Chludzińska, Marta; Ziętek, Piotr

2016-01-01

This paper presents the results of investigations whose aim was to describe the influence of the pressure difference level on the ability of contaminants migration between neighbouring rooms in dynamic conditions associated with door swing. The analysis was based on airflow visualization made with cold smoke, which simulated the heavy contaminants. The test room was pressurized to a specific level and then the door was opened to observe the trail of the smoke plume in the plane of the door. The door was opened in both directions: to the positively and negatively pressurized room. This study focuses on the visualization of smoke plume discharge and an uncertainty analysis is not applicable. Unlike other studies which focus on the analysis of pressure difference, the present study looks at the contaminants which are heavier than air and on "pumping out" the contaminants by means of door swing. Setting the proper level of pressure difference between the contaminated room and the neighbouring rooms can prove instrumental in ensuring protection against toxic contaminants migration. This study helped to establish the threshold of pressure difference necessary to reduce migration of heavy contaminants to neighbouring rooms.

Investigation of broadening and shift of vapour absorption lines of H{sub 2}{sup 16}O in the frequency range 7184 – 7186 cm{sup -1}

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

Nadezhdinskii, A I; Pereslavtseva, A A; Ponurovskii, Ya Ya

2014-10-31

We present the results of investigation of water vapour absorption spectra in the 7184 – 7186 cm{sup -1} range that is of particular interest from the viewpoint of possible application of the data obtained for monitoring water vapour in the Earth's stratosphere. The doublet of H{sub 2}{sup 16}O near ν = 7185.596 cm{sup -1} is analysed. The coefficients of broadening and shift of water vapour lines are found in the selected range in mixtures with buffer gases and compared to those obtained by other authors. (laser spectroscopy)

Localisation of an Unknown Number of Land Mines Using a Network of Vapour Detectors

PubMed Central

Chhadé, Hiba Haj; Abdallah, Fahed; Mougharbel, Imad; Gning, Amadou; Julier, Simon; Mihaylova, Lyudmila

2014-01-01

We consider the problem of localising an unknown number of land mines using concentration information provided by a wireless sensor network. A number of vapour sensors/detectors, deployed in the region of interest, are able to detect the concentration of the explosive vapours, emanating from buried land mines. The collected data is communicated to a fusion centre. Using a model for the transport of the explosive chemicals in the air, we determine the unknown number of sources using a Principal Component Analysis (PCA)-based technique. We also formulate the inverse problem of determining the positions and emission rates of the land mines using concentration measurements provided by the wireless sensor network. We present a solution for this problem based on a probabilistic Bayesian technique using a Markov chain Monte Carlo sampling scheme, and we compare it to the least squares optimisation approach. Experiments conducted on simulated data show the effectiveness of the proposed approach. PMID:25384008

Vapour-Deposited Cesium Lead Iodide Perovskites: Microsecond Charge Carrier Lifetimes and Enhanced Photovoltaic Performance

PubMed Central

2017-01-01

Metal halide perovskites such as methylammonium lead iodide (MAPbI3) are highly promising materials for photovoltaics. However, the relationship between the organic nature of the cation and the optoelectronic quality remains debated. In this work, we investigate the optoelectronic properties of fully inorganic vapour-deposited and spin-coated black-phase CsPbI3 thin films. Using the time-resolved microwave conductivity technique, we measure charge carrier mobilities up to 25 cm2/(V s) and impressively long charge carrier lifetimes exceeding 10 μs for vapour-deposited CsPbI3, while the carrier lifetime reaches less than 0.2 μs in the spin-coated samples. Finally, we show that these improved lifetimes result in enhanced device performance with power conversion efficiencies close to 9%. Altogether, these results suggest that the charge carrier mobility and recombination lifetime are mainly dictated by the inorganic framework rather than the organic nature of the cation. PMID:28852710

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

Martínez-Ruiz, F. J.; Blas, F. J., E-mail: felipe@uhu.es; Centro de Investigación de Física Teórica y Matemática, Universidad de Huelva, 21071 Huelva

We propose an extension of the improved version of the inhomogeneous long-range corrections of Janeček [J. Phys. Chem. B 110, 6264–6269 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] to account for the intermolecular potential energy of spherical, rigid, and flexible molecular systems, to deal with the contributions to the microscopic components of the pressure tensor due to the dispersive long-range corrections. We have performed Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of spherical Lennard-Jones molecules with different cutoff distances, r{sub c} = 2.5, 3, 4, and 5σ. In addition,more » we have also considered cutoff distances r{sub c} = 2.5 and 3σ in combination with the inhomogeneous long-range corrections proposed in this work. The normal and tangential microscopic components of the pressure tensor are obtained using the mechanical or virial route in combination with the recipe of Irving and Kirkwood, while the macroscopic components are calculated using the Volume Perturbation thermodynamic route proposed by de Miguel and Jackson [J. Chem. Phys. 125, 164109 (2006)]. The vapour-liquid interfacial tension is evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the Test-Area methodology. In addition to the pressure tensor and the surface tension, we also obtain density profiles, coexistence densities, vapour pressure, critical temperature and density, and interfacial thickness as functions of temperature, paying particular attention to the effect of the cutoff distance and the long-range corrections on these properties. According to our results, the main effect of increasing the cutoff distance (at fixed temperature) is to sharpen the vapour-liquid interface, to decrease the vapour pressure, and to increase the width of the biphasic coexistence region. As a result, the

Determination of the amount of physical adsorption of water vapour on platinum-iridium surfaces

NASA Astrophysics Data System (ADS)

Mizushima, S.; Ueda, K.; Ooiwa, A.; Fujii, K.

2015-08-01

This paper presents the measurement of the physical adsorption of water vapour on platinum-iridium surfaces using a vacuum mass comparator. This value is of importance for redefining the kilogram, which will be realized under vacuum in the near future. Mirror-polished artefacts, consisting of a reference artefact and a test artefact, were manufactured for this experiment. The surface area difference between the reference and test artefacts was 226.2 cm2. This surface area difference was approximately 3.2 times the geometric surface area of the prototype of the kilogram made of platinum-iridium (71.7 cm2). The measurement results indicate that the amount of physical adsorption at a relative humidity of 50% is 0.0129 μg cm{{-}2} , with a standard uncertainty of 0.0016 μg cm{{-}2} . This value is 0.03 to 0.16 times that observed in other studies.

Intercomparison of in-situ and remote sensing δD signals in tropospheric water vapour

NASA Astrophysics Data System (ADS)

Schneider, Matthias; González, Yenny; Dyroff, Christoph; Christner, Emanuel; García, Omaira; Wiegele, Andreas; Andrey, Javier; Barthlott, Sabine; Blumenstock, Thomas; Guirado, Carmen; Hase, Frank; Ramos, Ramon; Rodríguez, Sergio; Sepúveda, Eliezer

2014-05-01

The main mission of the project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) is the generation of a quasi-global tropospheric water vapour isototopologue dataset of a good and well-documented quality. We present a first empirical validation of MUSICA's remote sensing δD products (ground-based FTIR within NDACC, Network for the Detection of Atmospheric Composition Change, and space-based with IASI, Infrared Atmospheric Sounding Interferometer, flown on METOP). As reference we use in-situ measurements made on the island of Tenerife at two different altitudes (2370 and 3550 m a.s.l., using two Picarro L2120-i water isotopologue analyzers) and aboard an aircraft (between 200 and 6800 m a.s.l., using the homemade ISOWAT instrument).

Assessing occupational mercury exposures and behaviours of artisanal and small-scale gold miners in Burkina Faso using passive mercury vapour badges.

PubMed

Black, Paleah; Richard, Myrianne; Rossin, Ricardo; Telmer, Kevin

2017-01-01

Artisanal and small-scale gold mining (ASGM) is a crucial economic activity in Burkina Faso, however it is associated with significant mercury exposure and health concerns. The aim of the present study was to assess the level of mercury (Hg) vapour exposures and occupational behaviours at a representative site using Hg vapour monitor badges and questionnaires. To our knowledge this is the first time that personal exposure to Hg vapour during ASGM activities has been reported. The study population were ASGM workers who completed a questionnaire (n=100) or participated with an occupational exposure assessment using commercially available passive Hg vapour samplers (n=44). Occupational exposure to Hg was high during open-air burn events with a time weighted average (TWA) exposure of 7026±6857µg/m 3 for burners, and 1412±2870µg/m 3 for bystanders. Most (82%) of the people present at the burn exceeded the Permissible Exposure Limit (PEL) of 100µg/m 3 , and 11% exceeded the level considered to be Immediately Dangerous to Life and Health (IDLH) of 10,000µg/m 3 . Even control workers who were not present at the burn exceeded the PEL (24%), likely due to legacy Hg contamination producing latent Hg releases to the atmosphere. Similarly, 86% of the miners at the burn and 59% of control workers had an 8-h TWA that exceeded the Recommended Exposures Limit (REL). Several occupational behaviours that may contribute to Hg exposures were documented. This study corroborates previous studies suggesting that Hg exposure during amalgam burning is very high, and demonstrates the plausibility of using passive vapour monitoring badges rather than costly and logistically difficult biomonitoring methods. Mercury reduction and elimination interventions are strongly needed to reduce Hg exposure in ASGM communities, particularly as countries come into compliance with the Minamata Convention. Copyright © 2016 Elsevier Inc. All rights reserved.

Ultra-fast vapour-liquid-solid synthesis of Si nanowires using ion-beam implanted gallium as catalyst.

PubMed

Hetzel, Martin; Lugstein, Alois; Zeiner, Clemens; Wójcik, Tomasz; Pongratz, Peter; Bertagnolli, Emmerich

2011-09-30

The feasibility of gallium as a catalyst for vapour-liquid-solid (VLS) nanowire (NW) growth deriving from an implantation process in silicon by a focused ion beam (FIB) is investigated. Si(100) substrates are subjected to FIB implantation of gallium ions with various ion fluence rates. NW growth is performed in a hot wall chemical vapour deposition (CVD) reactor at temperatures between 400 and 500 °C with 2% SiH(4)/He as precursor gas. This process results in ultra-fast growth of (112)- and (110)-oriented Si-NWs with a length of several tens of micrometres. Further investigation by transmission electron microscopy indicates the presence of a NW core-shell structure: while the NW core yields crystalline structuring, the shell consists entirely of amorphous material.

Characterisation of mainstream and passive vapours emitted by selected electronic cigarettes.

PubMed

Geiss, Otmar; Bianchi, Ivana; Barahona, Francisco; Barrero-Moreno, Josefa

2015-01-01

Electronic cigarettes have achieved growing popularity since their introduction onto the European market. They are promoted by manufacturers as healthier alternatives to tobacco cigarettes, however debate among scientists and public health experts about their possible impact on health and indoor air quality means further research into the product is required to ensure decisions of policymakers, health care providers and consumers are based on sound science. This study investigated and characterised the impact of 'vaping' (using electronic cigarettes) on indoor environments under controlled conditions using a 30m(3) emission chamber. The study determined the composition of e-cigarette mainstream vapour in terms of propylene glycol, glycerol, carbonyls and nicotine emissions using a smoking machine with adapted smoking parameters. Two different base recipes for refill liquids, with three different amounts of nicotine each, were tested using two models of e-cigarettes. Refill liquids were analysed on their content of propylene glycol, glycerol, nicotine and qualitatively on their principal flavourings. Possible health effects of e-cigarette use are not discussed in this work. Electronic cigarettes tested in this study proved to be sources for propylene glycol, glycerol, nicotine, carbonyls and aerosol particulates. The extent of exposure differs significantly for active and passive 'vapers' (users of electronic cigarettes). Extrapolating from the average amounts of propylene glycol and glycerol condensed on the smoking machine filter pad to the resulting lung-concentration, estimated lung concentrations of 160 and 220mgm(-3) for propylene glycol and glycerol were obtained, respectively. Vaping refill liquids with nicotine concentrations of 9mgmL(-1) led to vapour condensate nicotine amounts comparable to those of low-nicotine regular cigarettes (0.15-0.2mg). In chamber studies, peak concentrations of 2200μgm(-3) for propylene glycol, 136μgm(-3) for glycerol and 0.6�

Convective heat transfer measurements in a vapour-liquid-liquid three-phase direct contact heat exchanger

NASA Astrophysics Data System (ADS)

Mahood, Hameed B.; Campbell, A. N.; Baqir, Ali Sh.; Sharif, A. O.; Thorpe, R. B.

2018-06-01

Energy usage is increasing around the world due to the continued development of technology, and population growth. Solar energy is a promising low-grade energy resource that can be harvested and utilised in different applications, such solar heater systems, which are used in both domestic and industrial settings. However, the implementation of an efficient energy conversion system or heat exchanger would enhance such low-grade energy processes. The direct contact heat exchanger could be the right choice due to its ability to efficiently transfer significant amounts of heat, simple design, and low cost. In this work, the heat transfer associated with the direct contact condensation of pentane vapour bubbles in a three-phase direct contact condenser is investigated experimentally. Such a condenser could be used in a cycle with a solar water heater and heat recovery systems. The experiments on the steady state operation of the three-phase direct contact condenser were carried out using a short Perspex tube of 70 cm in total height and an internal diameter of 4 cm. Only a height of 48 cm was active as the direct contact condenser. Pentane vapour, (the dispersed phase) with three different initial temperatures (40° C, 43.5° C and 47.5° C) was directly contacted with water (the continuous phase) at 19° C. The experimental results showed that the total heat transfer rate per unit volume along the direct contact condenser gradually decreased upon moving higher up the condenser. Additionally, the heat transfer rate increases with increasing mass flow rate ratio, but no significant effect on the heat transfer rate of varying the initial temperature of the dispersed phase was seen. Furthermore, both the outlet temperature of the continuous phase and the void fraction were positively correlated with the total heat transfer rate per unit volume, with no considerable effect of the initial temperature difference between the dispersed and continuous phases.

Convective heat transfer measurements in a vapour-liquid-liquid three-phase direct contact heat exchanger

NASA Astrophysics Data System (ADS)

Mahood, Hameed B.; Campbell, A. N.; Baqir, Ali Sh.; Sharif, A. O.; Thorpe, R. B.

2017-12-01

Energy usage is increasing around the world due to the continued development of technology, and population growth. Solar energy is a promising low-grade energy resource that can be harvested and utilised in different applications, such solar heater systems, which are used in both domestic and industrial settings. However, the implementation of an efficient energy conversion system or heat exchanger would enhance such low-grade energy processes. The direct contact heat exchanger could be the right choice due to its ability to efficiently transfer significant amounts of heat, simple design, and low cost. In this work, the heat transfer associated with the direct contact condensation of pentane vapour bubbles in a three-phase direct contact condenser is investigated experimentally. Such a condenser could be used in a cycle with a solar water heater and heat recovery systems. The experiments on the steady state operation of the three-phase direct contact condenser were carried out using a short Perspex tube of 70 cm in total height and an internal diameter of 4 cm. Only a height of 48 cm was active as the direct contact condenser. Pentane vapour, (the dispersed phase) with three different initial temperatures (40° C, 43.5° C and 47.5° C) was directly contacted with water (the continuous phase) at 19° C. The experimental results showed that the total heat transfer rate per unit volume along the direct contact condenser gradually decreased upon moving higher up the condenser. Additionally, the heat transfer rate increases with increasing mass flow rate ratio, but no significant effect on the heat transfer rate of varying the initial temperature of the dispersed phase was seen. Furthermore, both the outlet temperature of the continuous phase and the void fraction were positively correlated with the total heat transfer rate per unit volume, with no considerable effect of the initial temperature difference between the dispersed and continuous phases.

Medial stabilized and posterior stabilized TKA affect patellofemoral kinematics and retropatellar pressure distribution differently.

PubMed

Glogaza, Alexander; Schröder, Christian; Woiczinski, Matthias; Müller, Peter; Jansson, Volkmar; Steinbrück, Arnd

2018-06-01

Patellofemoral kinematics and retropatellar pressure distribution change after total knee arthroplasty (TKA). It was hypothesized that different TKA designs will show altered retropatellar pressure distribution patterns and different patellofemoral kinematics according to their design characteristics. Twelve fresh-frozen knee specimens were tested dynamically in a knee rig. Each specimen was measured native, after TKA with a posterior stabilized design (PS) and after TKA with a medial stabilized design (MS). Retropatellar pressure distribution was measured using a pressure sensitive foil which was subdivided into three areas (lateral and medial facet and patellar ridge). Patellofemoral kinematics were measured by an ultrasonic-based three-dimensional motion system (Zebris CMS20, Isny Germany). Significant changes in patellofemoral kinematics and retropatellar pressure distribution were found in both TKA types when compared to the native situation. Mean retropatellar contact areas were significantly smaller after TKA (native: 241.1 ± 75.6 mm 2 , MS: 197.7 ± 74.5 mm 2 , PS: 181.2 ± 56.7 mm 2 , native vs. MS p < 0.001; native vs. PS p < 0.001). The mean peak pressures were significantly higher after TKA. The increased peak pressures were however seen in different areas: medial and lateral facet in the PS-design (p < 0.001), ridge in the MS design (p < 0.001). Different patellofemoral kinematics were found in both TKA designs when compared to the native knee during flexion and extension with a more medial patella tracking. Patellofemoral kinematics and retropatellar pressure change after TKA in different manner depending on the type of TKA used. Surgeons should be aware of influencing the risks of patellofermoral complications by the choice of the prosthesis design.

Differences in blood pressure by measurement technique in neurocritically ill patients: A technological assessment.

PubMed

Lele, Abhijit V; Wilson, Daren; Chalise, Prabhakar; Nazzaro, Jules; Krishnamoorthy, Vijay; Vavilala, Monica S

2018-01-01

Blood pressure data may vary by measurement technique. We performed a technological assessment of differences in blood pressure measurement between non-invasive blood pressure (NIBP) and invasive arterial blood pressure (ABP) in neurocritically ill patients. After IRB approval, a prospective observational study was performed to study differences in systolic blood pressure (SBP), mean arterial pressure (MAP), and cerebral perfusion pressure (CPP) values measured by NIBP arm, ABP at level of the phlebostatic axis (ABP heart) and ABP at level of the external auditory meatus (ABP brain) at 30 and 45-degree head of bed elevation (HOB) using repeated measure analysis of covariance and correlation coefficients. Overall, 168 patients were studied with median age of 57 ± 15 years, were mostly female (57%), with body mass index ≤30 (66%). Twenty-three percent (n = 39) had indwelling intracranial pressure monitors, and 19.7% (n = 33) received vasoactive agents. ABP heart overestimated ABP brain for SBP (11.5 ± 2.7 mmHg, p < .001), MAP (mean difference 13.3 ± 0.5 mmHg, p < .001) and CPP (13.4 ± 3.2 mmHg, p < .001). ABP heart overestimated NIBP arm for SBP (8 ± 1.5 mmHg, p < .001), MAP (mean difference 8.6 ± 0.8 mmHg, p < .001), and CPP (mean difference 9.8 ± 3.2 mmHg, p < .001). Regardless of HOB elevation, ABP heart overestimates MAP compared to ABP brain and NIBP arm. Using ABP heart data overestimates CPP and may be responsible for not achieving SBP, MAP or CPP targets aimed at the brain. Copyright © 2017 Elsevier Ltd. All rights reserved.

Different centre of pressure patterns within the golf stroke II: group-based analysis.

PubMed

Ball, K A; Best, R J

2007-05-01

Although the golf coaching literature stresses the importance of weight transfer during the swing, research has been conflicting or lacking statistical support. A potential problem with previous studies is that no attempt was made to account for different movement strategies in the golf swing. This study evaluated the relationship between centre of pressure measures and club head velocity within two previously identified swing styles, the "Front Foot" and "Reverse" styles. Thirty-nine Front Foot golfers and 19 Reverse golfers performed swings with a driver while standing on two force plates. From the force plate data, centre of pressure displacement, velocity, range, and timing parameters were calculated. Correlation and regression analysis indicated that a larger range of centre of pressure and a more rapid centre of pressure movement in the downswing was associated with a larger club head velocity at ball contact for the Front Foot group. For the Reverse golfers, positioning the centre of pressure further from the back foot at late backswing and a more rapid centre of pressure transfer towards the back foot at ball contact was associated with a larger club head velocity at ball contact. This study has highlighted the importance of identifying different movement strategies before evaluating performance measures, as different parameters were found to be important for the Front Foot and Reverse styles.

Uncontrolled Hemorrhage Differs From Volume- or Pressure-Matched Controlled Hemorrhage in Swine

DTIC Science & Technology

2007-10-01

differences between these models, we evaluated the relationship between blood volume loss and blood pressure in controlled versus uncontrolled hemorrhage...aortotomy; (2) group P, controlled hemorrhage matched to the blood pressure profile of group U; or (3) group V, controlled hemorrhage matched to the...hemorrhage and received no fluid resuscitation. Group U resulted in a blood loss of 17.6 T 0.7 mL kgj1 and a reduction in blood pressure to 28 T 3 mmHg at

Cryopreservation of human sperm: efficacy and use of a new nitrogen-free controlled rate freezer versus liquid nitrogen vapour freezing.

PubMed

Creemers, E; Nijs, M; Vanheusden, E; Ombelet, W

2011-12-01

Preservation of spermatozoa is an important aspect of assisted reproductive medicine. The aim of this study was to investigate the efficacy and use of a recently developed liquid nitrogen and cryogen-free controlled rate freezer and this compared with the classical liquid nitrogen vapour freezing method for the cryopreservation of human spermatozoa. Ten patients entering the IVF programme donated semen samples for the study. Samples were analysed according to the World Health Organization guidelines. No significant difference in total sperm motility after freeze-thawing between the new technique and classical technique was demonstrated. The advantage of the new freezing technique is that it uses no liquid nitrogen during the freezing process, hence being safer to use and clean room compatible. Investment costs are higher for the apparatus but running costs are only 1% in comparison with classical liquid nitrogen freezing. In conclusion, post-thaw motility of samples frozen with the classical liquid nitrogen vapour technique was comparable with samples frozen with the new nitrogen-free freezing technique. This latter technique can thus be a very useful asset to the sperm cryopreservation laboratory. © 2011 Blackwell Verlag GmbH.

Chemical Selectivity and Sensitivity of a 16-Channel Electronic Nose for Trace Vapour Detection

PubMed Central

Strle, Drago; Trifkovič, Mario; Van Miden, Marion; Kvasić, Ivan; Zupanič, Erik; Muševič, Igor

2017-01-01

Good chemical selectivity of sensors for detecting vapour traces of targeted molecules is vital to reliable detection systems for explosives and other harmful materials. We present the design, construction and measurements of the electronic response of a 16 channel electronic nose based on 16 differential microcapacitors, which were surface-functionalized by different silanes. The e-nose detects less than 1 molecule of TNT out of 10+12 N2 molecules in a carrier gas in 1 s. Differently silanized sensors give different responses to different molecules. Electronic responses are presented for TNT, RDX, DNT, H2S, HCN, FeS, NH3, propane, methanol, acetone, ethanol, methane, toluene and water. We consider the number density of these molecules and find that silane surfaces show extreme affinity for attracting molecules of TNT, DNT and RDX. The probability to bind these molecules and form a surface-adsorbate is typically 10+7 times larger than the probability to bind water molecules, for example. We present a matrix of responses of differently functionalized microcapacitors and we propose that chemical selectivity of multichannel e-nose could be enhanced by using artificial intelligence deep learning methods. PMID:29292764

[Effects of long time different negative pressures on osteogenic differentiation of rabbit bone mesenchymal stem cells].

PubMed

Zhao, Bowen; Zhang, Hongwei; Xu, Qiang; Ge, Quanhu; Li, Bolong; Peng, Xinyu; Wu, Xiangwei

2017-05-01

To investigate the effects of long time different negative pressures on osteogenic diffe-rentiation of rabbit bone mesenchymal stem cells (BMSCs). The rabbit BMSCs were isolated and cultured by density gradient centrifugation. Flow cytometry was used to analyze expression of surface markers. The third passage cells cultured under condition of osteogenic induction and under different negative pressure of 0 mm Hg (control group), 75 mm Hg (low negative pressure group), and 150 mm Hg (high negative pressure group) (1 mm Hg=0.133 kPa), and the negative pressure time was 30 min/h. Cell growth was observed under phase contrast microscopy, and the growth curve was drawn; alkaline phosphatase (ALP) activity was detected by ELISA after induced for 3, 7, and 14 days. The mRNA and protein expressions of collagen type I (COL-I) and osteocalcin (OC) in BMSCs were analyzed by real-time fluorescence quantitative PCR and Western blot. The cultured cells were identified as BMSCs by flow cytometry. The third passage BMSCs exhibited typical long shuttle and irregular shape. Cell proliferation was inhibited with the increase of negative pressure. After induced for 4 days, the cell number of high negative pressure group was significantly less than that in control group and low negative pressure group ( P <0.05), but there was no significant difference between the low negative pressure group and the control group ( P >0.05); at 5-7 days, the cell number showed significant difference between 3 groups ( P <0.05). The greater the negative pressure was, the greater the inhibition of cell proliferation was. There was no significant difference in ALP activity between groups at 3 days after induction ( P >0.05); the ALP activity showed significant difference ( P <0.05) between the high negative pressure group and the control group at 7 days after induction; and significant difference was found in the ALP activity between 3 groups at 14 days after induction ( P <0.05). The greater the negative

Functional differences in bi-level pressure preset ventilators.

PubMed

Highcock, M P; Shneerson, J M; Smith, I E

2001-02-01

The performance of four bilevel positive pressure preset ventilators was compared. The ventilators tested were; BiPAP ST30 (Respironics); Nippy2 (B + D Electrical); Quantum PSV (Healthdyne); and Sullivan VPAP H ST (Resmed). A patient simulator was used to determine the sensitivity of the triggering mechanisms and the responses to a leak within the patient circuit, and to changes in patient effort. Significant differences (p <0.05) between the devices were seen in the trigger delay time and inspiratory trigger pressure. When a leak was introduced into the patient circuit, the fall in tidal volume (VT) was less than ten per cent for each ventilator. The addition of patient effort produced a number of changes in the ventilation delivered. Patient efforts of 0.25 s induced a variable fall in VT. An increase in VT was seen with some ventilators with patient efforts of 1 s but the effect was variable. Trigger failures and subsequent falls in minute volume were seen with the BiPAP and the Nippy2 at the highest respiratory frequency. Differences in the responses of the ventilators are demonstrated that may influence the selection of a ventilator, particularly in the treatment of breathless patients with ventilatory failure.

Inter-arm blood pressure differences compared with ambulatory monitoring: a manifestation of the ‘white-coat’ effect?

PubMed Central

Martin, Una; Holder, Roger; Hodgkinson, James; McManus, Richard

2013-01-01

Background Inter-arm difference in blood pressure of >10 mmHg is associated with peripheral vascular disease, but it is unclear how much of the difference in sequential right and left arm blood pressure measurements might be due to a ‘white-coat’ effect. Aim To use ambulatory blood pressure monitoring (ABPM) to better understand the clinical significance of inter-arm differences in blood pressure. Design and setting Retrospective study in a teaching hospital in Birmingham. Method Anonymised clinical data collected from 784 patients attending a single hospital-based hypertension clinic were retrospectively analysed. Each participant had blood pressure measured sequentially in both arms, followed by ABPM over the subsequent 24 hours. Result Data were available for 710 (91%) patients, of whom 39.3% (279) had a blood pressure difference of 10 mmHg or more between each arm. Compared to daytime systolic ABPM, the difference was 25.1 mmHg using the arm with the highest reading, but only 15.5 mmHg if the lower reading was taken (mean difference 9.6 mmHg (95% confidence interval [CI] = 9.0 mmHg to 10.3 mmHg)). However, differences between mean right (20.7 mmHg) or left (19.9 mmHg) arm blood pressure and daytime systolic ABPM were very similar. Conclusion Compared with ABPM, use of the higher of the left and right arm readings measured sequentially appears to overestimate true mean blood pressure. As there is no significant difference in the extent of disparity with ABPM by left or right arm, this is unlikely to be due to arm dominance and may be due to the ‘white-coat’ effect reducing blood pressure on repeated measurement. Where a large inter-arm blood pressure difference is detected with sequential measurement, healthcare professionals should re-measure the blood pressure in the original arm. PMID:23561681

Effect of Different Levels of Pressure Relieving Air-Mattress Firmness on Cough Strength.

PubMed

Kamikawa, Norimichi; Taito, Shunsuke; Takahashi, Makoto; Sekikawa, Kiyokazu; Hamada, Hironobu

2016-01-01

Cough is an important host-defense mechanism. The elderly and patients who are severely ill cannot cough effectively when lying in the supine position. Furthermore, pressure relieving air-mattresses are recommended for preventing the development of pressure ulcers. In this study, we clarified whether or not the cough peak flow (CPF), an index of cough strength, is affected by different firmness levels of a pressure relieving air-mattress in healthy volunteers in the supine position. Fifty-two healthy young men participated. All the measurements were carried out on each participant in the supine position on a pressure relieving air-mattress. The participants were assessed at two firmness levels, a "hard" and "soft" mode. The CPF, forced vital capacity (FVC), maximal expiratory pressure (PEmax), and maximal inspiratory pressure (PImax) were determined for each mode. The sinking distance of the body into the mattress was measured without any activity and the difference between the sinking distances of the two firmness levels was determined. The CPF, FVC, PEmax, and PImax were determined for each mode. The sinking distance of the body into the mattress was measured and the difference between the sinking distances of the two firmness levels was determined. The CPF, FVC, PEmax and PImax values of the participants coughing on the mattress were significantly lower when the mattress was in "soft" than in "hard" mode. The differences between the sinking distances of the mattress in "soft" and "hard" modes were larger for the anterior superior iliac spine. A harder mattress may lead to increased CPF in healthy young men lying in the supine position, and increased CPF may be important for host defense.

Racial differences in barriers to blood pressure control in a family practice setting.

PubMed

Scott, Jonathan M; Spees, Colleen K; Taylor, Christopher A; Wexler, Randy

2010-10-01

Hypertension prevalence in the African American community is greater than in all other ethnic groups. Cultural perceptions of health and disease introduce barriers to providing effective care. The purpose of this study was to identify racial differences in the perceived causes of hypertension, current behaviors performed to control blood pressure, and perceived barriers to preventing or treating hypertension. A self-administered survey of patients seen for medical care in a primary care network was conducted. The survey was developed to measure perceptions of hypertension etiology and treatments. Data from African American (n = 69) and Caucasian (n = 218) respondents were used to assess racial differences in perceptions of blood pressure control. About half of respondents knew their current blood pressures. African American patients were significantly less likely to believe that hypertension was caused by a lack of exercise and obesity. Significantly more Caucasians were less likely to report cutting down on table salt and taking prescription medications for blood pressure control. Both African Americans and Caucasians believed that sodium reduction was the most easily changed behavior to control their blood pressure, while both groups identified weight loss as being the most difficult. Racial differences exist in the perceived causes and treatments of high blood pressure, indicating a need for further patient education. When treating and counseling patients, physicians and support staff members must be sensitive to racial diversity and strive to offer culturally relevant solutions, especially for behaviors perceived as most difficult to change.

A novel three-jet microreactor for localized metal-organic chemical vapour deposition of gallium arsenide: design and simulation

NASA Astrophysics Data System (ADS)

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

2016-08-01

We present a novel three-jet microreactor design for localized deposition of gallium arsenide (GaAs) by low-pressure Metal-Organic Chemical Vapour Deposition (MOCVD) for semiconductor devices, microelectronics and solar cells. Our approach is advantageous compared to the standard lithography and etching technology, since it preserves the nanostructure of the deposited material, it is less time-consuming and less expensive. We designed two versions of reactor geometry with a 10-micron central microchannel for precursor supply and with two side jets of a dilutant to control the deposition area. To aid future experiments, we performed computational modeling of a simplified-geometry (twodimensional axisymmetric) microreactor, based on Navier-Stokes equations for a laminar flow of chemically reacting gas mixture of Ga(CH3)3-AsH3-H2. Simulation results show that we can achieve a high-rate deposition (over 0.3 μm/min) on a small area (less than 30 μm diameter). This technology can be used in material production for microelectronics, optoelectronics, photovoltaics, solar cells, etc.

Water vapour and wind measurements by a two micron space lidar

NASA Astrophysics Data System (ADS)

Ghibaudo, J.-B.; Labandibar, J.-Y.

2018-04-01

AEROSPATIALE presents the main results of the feasibility study under ESA contract on a coherent 2μm lidar instrument capable of measuring water vapour and wind velocity in the planetary boundary layer. The selected instrument configuration and the associated performance are provided, and the main critical subsystems identified (laser configuration, coherent receiver chain architecture, frequency locking and offsetting architecture. The second phase of this study is dedicated to breadboard the most critical elements of such an instrument in order to technologically consolidate its feasibility.

Development of a custom on-line ultrasonic vapour analyzer and flow meter for the ATLAS inner detector, with application to Cherenkov and gaseous charged particle detectors

NASA Astrophysics Data System (ADS)

Alhroob, M.; Bates, R.; Battistin, M.; Berry, S.; Bitadze, A.; Bonneau, P.; Bousson, N.; Boyd, G.; Bozza, G.; Crespo-Lopez, O.; Degeorge, C.; Deterre, C.; DiGirolamo, B.; Doubek, M.; Favre, G.; Godlewski, J.; Hallewell, G.; Hasib, A.; Katunin, S.; Langevin, N.; Lombard, D.; Mathieu, M.; McMahon, S.; Nagai, K.; O'Rourke, A.; Pearson, B.; Robinson, D.; Rossi, C.; Rozanov, A.; Strauss, M.; Vacek, V.; Zwalinski, L.

2015-03-01

Precision sound velocity measurements can simultaneously determine binary gas composition and flow. We have developed an analyzer with custom microcontroller-based electronics, currently used in the ATLAS Detector Control System, with numerous potential applications. Three instruments monitor C3F8 and CO2 coolant leak rates into the nitrogen envelopes of the ATLAS silicon microstrip and Pixel detectors. Two further instruments will aid operation of the new thermosiphon coolant recirculator: one of these will monitor air leaks into the low pressure condenser while the other will measure return vapour flow along with C3F8/C2F6 blend composition, should blend operation be necessary to protect the ATLAS silicon tracker under increasing LHC luminosity. We describe these instruments and their electronics.

Microwave measurements of temperature profiles, integrated water vapour, and liquid water path at Thule Air Base, Greenland.

NASA Astrophysics Data System (ADS)

Pace, Giandomenico; Di Iorio, Tatiana; di Sarra, Alcide; Iaccarino, Antonio; Meloni, Daniela; Mevi, Gabriele; Muscari, Giovanni; Cacciani, Marco

2017-04-01

A RPG Humidity And Temperature PROfiler (HATPRO-G2 ) radiometer was installed at Thule Air Base (76.5° N, 68.8° W), Greenland, in June 2016 in the framework of the Study of the water VApour in the polar AtmosPhere (SVAAP) project. The Danish Meteorological Institute started measurements of atmospheric properties at Thule Air Base in early '90s. The Thule High Arctic Atmospheric Observatory (THAAO) has grown in size and observing capabilities during the last three decades through the international effort of United States (NCAR and University of Alaska Fairbanks) and Italian (ENEA, INGV, University of Roma and Firenze) institutions (http://www.thuleatmos-it.it). Within this context, the intensive field campaign of the SVAAP project was aimed at the investigation of the surface radiation budget and took place from 5 to 28 July, 2016. After the summer campaign the HATPRO has continued to operate in order to monitor the annual variability of the temperature profile and integrated water vapour as well as the presence and characteristics of liquid clouds in the Artic environment. The combined use of the HATPRO together with other automatic instruments, such as a new microwave spectrometer (the water Vapour Emission Spectrometer for Polar Atmosphere VESPA-22), upward- and downward-looking pyranometers and pyrgeometers, a zenith-looking pyrometer operating in the 9.6-11.5 µm spectral range, an all sky camera, and a meteorological station, allows to investigate the clouds' physical and optical properties, as well as their impact on the surface radiation budget. This study will present and discuss the first few months of HATPRO observations; the effectiveness of the statistical retrieval used to derive the physical parameters from the HATPRO brightness temperatures will also be investigated through the comparison of the temperature and humidity profiles, and integrated water vapour, with data from radiosondes launched during the summer campaign and in winter time.

Measurement of pressure changes during laser-activated irrigant by an erbium, chromium: yttrium, scandium, gallium, garnet laser.

PubMed

Peeters, Harry Huiz; De Moor, Roeland J G

2015-07-01

The use of Er,Cr:YSGG laser to activate irrigants results in the creation of vapour bubbles and shockwaves. The present study evaluated the magnitude of pressure changes in the root canal during laser-activated irrigation. The root canal of a single extracted maxillary canine was enlarged to a size 40/0.06 file. A pressure sensor was inserted apically into the root canal. The tooth was processed as follows. In the EDTA condition, the tooth was irrigated with 17 % EDTA; in the NaOCl condition, the tooth was irrigated with 3 % NaOCl. In all conditions, the irrigants were activated at 0.75 and 1.75 W for 60 s using RFT2 and MZ2 tips; to analyse the effect of tip placement, the tip was activated at the orifice and after inserting the tip 5 mm deeper than the orifice. Data showed no significant difference between irrigation regimens (p > 0.05). There were no significant differences of the pressure between RFT2 and MZ2 tips (p > 0.05). The placement of tips closer to the apex resulted in significantly higher pressure than at the orifice (p < 0.001). The use of 1.75 W power resulted in a significantly higher increase of pressure compared to 0.75 W (p < 0.001), regardless either the type of solutions or tips used. The magnitude of the pressure changes in the root canal at 0.75 W was significantly lower than 1.75 W regardless of either type of tips or solutions used. The closer the insertion of the tip to the apex, the higher the pressure.

Chemical vapour deposition growth and Raman characterization of graphene layers and carbon nanotubes

NASA Astrophysics Data System (ADS)

Lai, Y.-C.; Rafailov, P. M.; Vlaikova, E.; Marinova, V.; Lin, S. H.; Yu, P.; Yu, S.-C.; Chi, G. C.; Dimitrov, D.; Sveshtarov, P.; Mehandjiev, V.; Gospodinov, M. M.

2016-02-01

Single-layer graphene films were grown by chemical vapour deposition (CVD) on Cu foil. The CVD process was complemented by plasma enhancement to grow also vertically aligned multiwalled carbon nanotubes using Ni nanoparticles as catalyst. The obtained samples were characterized by Raman spectroscopy analysis. Nature of defects in the samples and optimal growth conditions leading to achieve high quality of graphene and carbon nanotubes are discussed.

A prospective randomized trial of postoperative pain following different insufflation pressures during gynecologic laparoscopy.

PubMed

Topçu, H O; Cavkaytar, S; Kokanalı, K; Guzel, A I; Islimye, M; Doganay, M

2014-11-01

To determine the effects of different intra-abdominal pressure values on visceral pain following gynecologic laparoscopic surgery in the Trendelenburg position. This randomized, controlled prospective trial was conducted at a tertiary education hospital and included 150 patients who underwent gynecologic laparoscopy with different abdominal insufflation pressures. There were 54 patients in the 8 mmHg low pressure group (LPG), 45 in the 12 mmHg standard pressure group (SPG), and 51 in the 15 mmHg high pressure group (HPG). We assessed mean age, body mass index (BMI), duration of surgery, analgesic consumption, length of hospital stay, amount of CO2 expended and volume of hemorrhage. Visceral pain and referred visceral pain were assessed 6, 12, and 24 h postoperatively using a visual analog scale (VAS). There was no significant difference in age, BMI, analgesic consumption or length of hospital stay among groups. The mean operative time and total CO2 expended during surgery were higher in the LPG compared with the SPG and HPG. The mean intensity of postoperative pain assessed by the VAS score at 6 and 12 h was less in the LPG than in the SPG and HPG and was reduced significantly at 12 h. VAS scores at 24 h in the LPG and SPG were lower than in the HPG. Pain is reduced by low insufflation pressure compared with standard and high insufflation pressure following gynecologic laparoscopic surgery in the Trendelenburg position. However, low insufflation pressure may result in longer operation times and increased hemorrhage. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Effect of Different Levels of Pressure Relieving Air-Mattress Firmness on Cough Strength

PubMed Central

Kamikawa, Norimichi; Taito, Shunsuke; Takahashi, Makoto; Sekikawa, Kiyokazu; Hamada, Hironobu

2016-01-01

Cough is an important host-defense mechanism. The elderly and patients who are severely ill cannot cough effectively when lying in the supine position. Furthermore, pressure relieving air-mattresses are recommended for preventing the development of pressure ulcers. In this study, we clarified whether or not the cough peak flow (CPF), an index of cough strength, is affected by different firmness levels of a pressure relieving air-mattress in healthy volunteers in the supine position. Fifty-two healthy young men participated. All the measurements were carried out on each participant in the supine position on a pressure relieving air-mattress. The participants were assessed at two firmness levels, a “hard” and “soft” mode. The CPF, forced vital capacity (FVC), maximal expiratory pressure (PEmax), and maximal inspiratory pressure (PImax) were determined for each mode. The sinking distance of the body into the mattress was measured without any activity and the difference between the sinking distances of the two firmness levels was determined. The CPF, FVC, PEmax, and PImax were determined for each mode. The sinking distance of the body into the mattress was measured and the difference between the sinking distances of the two firmness levels was determined. The CPF, FVC, PEmax and PImax values of the participants coughing on the mattress were significantly lower when the mattress was in “soft” than in “hard” mode. The differences between the sinking distances of the mattress in “soft” and “hard” modes were larger for the anterior superior iliac spine. A harder mattress may lead to increased CPF in healthy young men lying in the supine position, and increased CPF may be important for host defense. PMID:26741497

The water vapour self-continuum absorption in the infrared atmospheric windows: new laser measurements near 3.3 and 2.0 µm

NASA Astrophysics Data System (ADS)

Lechevallier, Loic; Vasilchenko, Semen; Grilli, Roberto; Mondelain, Didier; Romanini, Daniele; Campargue, Alain

2018-04-01

The amplitude, the temperature dependence, and the physical origin of the water vapour absorption continuum are a long-standing issue in molecular spectroscopy with direct impact in atmospheric and planetary sciences. In recent years, we have determined the self-continuum absorption of water vapour at different spectral points of the atmospheric windows at 4.0, 2.1, 1.6, and 1.25 µm, by highly sensitive cavity-enhanced laser techniques. These accurate experimental constraints have been used to adjust the last version (3.2) of the semi-empirical MT_CKD model (Mlawer-Tobin_Clough-Kneizys-Davies), which is widely incorporated in atmospheric radiative-transfer codes. In the present work, the self-continuum cross-sections, CS, are newly determined at 3.3 µm (3007 cm-1) and 2.0 µm (5000 cm-1) by optical-feedback-cavity enhanced absorption spectroscopy (OFCEAS) and cavity ring-down spectroscopy (CRDS), respectively. These new data allow extending the spectral coverage of the 4.0 and 2.1 µm windows, respectively, and testing the recently released 3.2 version of the MT_CKD continuum. By considering high temperature literature data together with our data, the temperature dependence of the self-continuum is also obtained.

Evaluation of Different Dose-Response Models for High Hydrostatic Pressure Inactivation of Microorganisms

PubMed Central

2017-01-01

Modeling of microbial inactivation by high hydrostatic pressure (HHP) requires a plot of the log microbial count or survival ratio versus time data under a constant pressure and temperature. However, at low pressure and temperature values, very long holding times are needed to obtain measurable inactivation. Since the time has a significant effect on the cost of HHP processing it may be reasonable to fix the time at an appropriate value and quantify the inactivation with respect to pressure. Such a plot is called dose-response curve and it may be more beneficial than the traditional inactivation modeling since short holding times with different pressure values can be selected and used for the modeling of HHP inactivation. For this purpose, 49 dose-response curves (with at least 4 log10 reduction and ≥5 data points including the atmospheric pressure value (P = 0.1 MPa), and with holding time ≤10 min) for HHP inactivation of microorganisms obtained from published studies were fitted with four different models, namely the Discrete model, Shoulder model, Fermi equation, and Weibull model, and the pressure value needed for 5 log10 (P5) inactivation was calculated for all the models above. The Shoulder model and Fermi equation produced exactly the same parameter and P5 values, while the Discrete model produced similar or sometimes the exact same parameter values as the Fermi equation. The Weibull model produced the worst fit (had the lowest adjusted determination coefficient (R2adj) and highest mean square error (MSE) values), while the Fermi equation had the best fit (the highest R2adj and lowest MSE values). Parameters of the models and also P5 values of each model can be useful for the further experimental design of HHP processing and also for the comparison of the pressure resistance of different microorganisms. Further experiments can be done to verify the P5 values at given conditions. The procedure given in this study can also be extended for enzyme

GNSS-Derived Water Vapour for Riyadh from SOLA IGS Station

NASA Astrophysics Data System (ADS)

Maghrabi, Abdullrahman; Alothman, Abdulaziz; Fernandes, Rui; Aodah, Souad

2017-04-01

Water vapor is the most abundant and highly variable component of the important gases in the atmosphere. It influences many physical and thermodynamical processes in the atmosphere and plays an important role in the hydrological cycle and has effects on our climate and weather systems. Water vapour affects the electromagnetic radiation through the atmosphere, which is of significance in fields of astronomy, radar, communications and remote sensing. Precipitable water vapor (PWV) is the amount of water obtained if all the water vapor in the atmosphere were to be compressed to the point at which it condenses into liquid. PWV is difficult to measure adequately due to its variable distribution both spatially and temporally. Most of the current techniques (e.g., radiosondes or satellites) are only available at few locations and not continuously (few observations per day at most). However, in the last decades, GPS observations have been proven to accurately measure the ZTD (Zenith Tropospheric Delay) at high frequencies (normally every 5 minutes) above the station. This quantity can be converted to PWV if temperature and pressure is know at the station location. In early 2004, King Abdulaziz City for Science and Technology (KACST) established a GPS network for geodetic and geophysical applications to contribute to the International GNSS Service IGS. In this study, we will present the first PWV measurements obtained from Global Navigation Satellite System GNSS receiver at the Solar Village (SOLA), 60 km from Riyadh. GNSS observations for the period between 2004-2006 are used to study the daily and seasonal variations of ZTD, and consequently of PWV in SOLA. In addition, we also compare the GNSS-derived PWV with sunphotometer and radiosonde estimates at SOLA in order to evaluate the compatibility of these techniques in a dry climate as the one in Riyadh.

Ethnic differences in blood pressure, pulse rate, and related characteristics in young adults. The CARDIA study.

PubMed

Liu, K; Ballew, C; Jacobs, D R; Sidney, S; Savage, P J; Dyer, A; Hughes, G; Blanton, M M

1989-08-01

This study examined ethnic differences in blood pressure and pulse rate in young adults to see whether the differences, if they exist, can be explained by differences in body mass index, lifestyle, psychological, and socioeconomic characteristics. Data used were from the baseline examination of the Coronary Artery Risk Development in (Young) Adults Study (CARDIA). CARDIA is a longitudinal study of lifestyle and evolution of cardiovascular disease risk factors in 5,116 young adults, black and white, men and women, aged 18-30 years, of varying socioeconomic status. Young black adults had higher mean systolic blood pressure and slightly higher mean diastolic blood pressure than young white adults. For both men and women, the blood pressure differences between blacks and whites tended to be greater for the age group 25-30 than for the age group 18-24 years. Among the variables studied, body mass index, duration of exercise on the treadmill, number of cigarettes smoked per day, and number of alcoholic drinks per week were consistently associated with blood pressure. The blood pressure differences were greatly reduced after adjusting for these variables. Black participants had lower mean pulse rate than white participants. The differences tended to be greater for the age group 18-24 than for the age group 25-30 years. Among the variables studied, only duration on treadmill and number of cigarettes smoked per day were consistently correlated with pulse rate. With adjustment for duration on treadmill, the differences in pulse rate increased. These results suggest that differences in ethnic pattern of blood pressures and pulse rate with age may be due in part to obesity, physical fitness, alcohol consumption, and cigarette smoking.

Major element and oxygen isotope geochemistry of vapour-phase garnet from the Topopah Spring Tuff at Yucca Mountain, Nevada, USA

USGS Publications Warehouse

Moscati, Richard J.; Johnson, Craig A.

2014-01-01

Twenty vapour-phase garnets were studied in two samples of the Topopah Spring Tuff of the Paintbrush Group from Yucca Mountain, in southern Nevada. The Miocene-age Topopah Spring Tuff is a 350 m thick, devitrified, moderately to densely welded ash-flow tuff that is zoned compositionally from high-silica rhyolite to latite. During cooling of the tuff, escaping vapour produced lithophysae (former gas cavities) lined with an assemblage of tridymite (commonly inverted to cristobalite or quartz), sanidine and locally, hematite and/or garnet. Vapour-phase topaz and economic deposits associated commonly with topaz-bearing rhyolites (characteristically enriched in F) were not found in the Topopah Spring Tuff at Yucca Mountain. Based on their occurrence only in lithophysae, the garnets are not primary igneous phenocrysts, but rather crystals that grew from a F-poor magma-derived vapour trapped during and after emplacement of the tuff. The garnets are euhedral, vitreous, reddish brown, trapezohedral, as large as 2 mm in diameter and fractured. The garnets also contain inclusions of tridymite. Electron microprobe analyses of the garnets reveal that they are almandine-spessartine (48.0 and 47.9 mol.%, respectively), have an average composition of (Fe1.46Mn1.45Mg0.03Ca0.10)(Al1.93Ti0.02)Si3.01O12 and are comparatively homogeneous in Fe and Mn concentrations from core to rim. Composited garnets from each sample site have δ18O values of 7.2 and 7.4‰. The associated quartz (after tridymite) has δ18O values of 17.4 and 17.6‰, values indicative of reaction with later, low-temperature water. Unaltered tridymite from higher in the stratigraphic section has a δ18O of 11.1‰ which, when coupled with the garnet δ18O values in a quartz-garnet fractionation equation, indicates isotopic equilibration (vapour-phase crystallization) at temperatures of ~600°C. This high-temperature mineralization, formed during cooling of the tuffs, is distinct from the later and commonly recognized

[The interarm blood pressure difference in the critically ill patient].

PubMed

Valls Matarín, Josefa; del Cotillo Fuente, Mercedes; Quintana Riera, Salvador; de la Sierra Iserte, Alejandro

2014-02-04

To evaluate the prevalence of a difference in systolic blood pressure (SBPd) ≥ 10 mmHg between arms in patients admitted in a Critical Care Unit and to examine the clinical characteristics associated with such blood pressure difference. Observational cross-sectional study. Two blood pressure measurements in each arm were carried out at unit admission. The firstly measured arm was chosen at random. One-hundred and sixty-eight patients were studied, with a mean age of 61 (SD=16), 67.3% male and 45% with a previous hypertension diagnosis. On admission, 27.4% presented SBPd ≥ 10 mmHg. Among them, 54% had higher SBP in the right arm and 46% in the left one. A SBPd ≥ 10 mmHg was associated with a previous hypertension diagnosis (67.4 versus 36.9%; P<.001) and with reduced consciousness (76.1 versus 52.5%; P=.006). Over a quarter of critically ill patients have a SBPd ≥ 10 mmHg between arms. This feature is associated with a previous hypertension diagnosis and reduced consciousness. It should be assessed in the future if the choice of a control arm would help improve patient's care as it would become a more accurate guide for hemodynamic management. Copyright © 2012 Elsevier España, S.L. All rights reserved.

Quality changes of fresh-cut pomegranate arils during shelf life as affected by deficit irrigation and postharvest vapour treatments.

PubMed

Peña-Estévez, María E; Gómez, Perla A; Artés, Francisco; Aguayo, Encarna; Martínez-Hernández, Ginés Benito; Otón, Mariano; Galindo, Alejandro; Artés-Hernández, Francisco

2015-08-30

The effect of two sustained deficit irrigation (SDI) strategies, compared to a control, on postharvest physicochemical, microbial, sensory quality attributes and anthocyanin content of fresh-cut pomegranates arils throughout 18 days at 5 °C was studied. Furthermore, the effect of vapour treatments (4, 7 and 10 s) compared to a conventional sanitizing treatment with NaClO on such quality parameters in combination with the preharvest treatments was also studied. According to sensory analyses, the shelf life of arils from control and SDI-irrigated fruit was established in 14 and 18 days at 5 °C, respectively, showing 4 and 7 s vapour treatment time the best sensory quality. No significant change was observed in physicochemical quality attributes, across all treatments during storage, while low microbial loads were registered (<3 log CFU g(-1)) after shelf life. Postharvest treatments that had least effect on anthocyanin content on processing day were 7 and 10 s. Vapour treatments of 7-10 s applied to pomegranate arils led to an extended shelf life up to 18 days at 5 °C with better results in SDI-irrigated samples with a water saving of 6-11%. © 2014 Society of Chemical Industry.

The effect of temperature and gas flow on the physical vapour growth of mm-scale rubrene crystals for organic FETs

NASA Astrophysics Data System (ADS)

Ullah, A. R.; Micolich, A. P.; Cochrane, J. W.; Hamilton, A. R.

2007-12-01

There has recently been significant interest in rubrene single-crystals grown using physical vapour transport techniques due to their application in high-mobility organic field-effect transistor (OFET) devices. Despite numerous studies of the electrical properties of such crystals, there has only been one study to date focussing on characterising and optimising the crystal growth as a function of the relevant growth parameters. Here we present a study of the dependence of the yield of useful crystals (defined as crystals with at least one dimension of order 1 mm) on the temperature and volume flow of carrier gas used in the physical vapour growth process.

Impedimetric detection of alcohol vapours using nanostructured zinc ferrite.

PubMed

Kannan, Padmanathan Karthick; Saraswathi, Ramiah

2014-11-01

A comparative study on the sensing characteristics of nanostructured zinc ferrite to three primary alcohols viz. methanol, ethanol and propanol has been carried out. The zinc ferrite has been prepared by a combustion method and characterized by XRD, FTIR, AFM and SEM. Impedance studies in the alcohol concentration range varying from 100 to 1000 ppm show definite variations in response to both the nature of the alcohol and its concentration. The nanostructured zinc ferrite shows the highest sensor response to methanol and least to propanol. Equivalent circuit modelling and calibration have been made for all the three alcohol sensors. The material shows a better selectivity to the alcohols compared to formaldehyde, ammonia and acetone vapours. Copyright © 2014 Elsevier B.V. All rights reserved.

Chemical vapour deposition: Transition metal carbides go 2D

DOE PAGES

Gogotsi, Yury

2015-08-17

Here, the research community has been steadily expanding the family of few-atom-thick crystals beyond graphene, discovering new materials or producing known materials in a 2D state and demonstrating their unique properties 1, 2. Recently, nanometre-thin 2D transition metal carbides have also joined this family 3. Writing in Nature Materials, Chuan Xu and colleagues now report a significant advance in the field, showing the synthesis of large-area, high-quality, nanometre-thin crystals of molybdenum carbide that demonstrate low-temperature 2D superconductivity 4. Moreover, they also show that other ultrathin carbide crystals, such as tungsten and tantalum carbides, can be grown by chemical vapour depositionmore » with a high crystallinity and very low defect concentration.« less

E-GVAP, the EIG EUMETNET GNSS Water Vapour Programme

NASA Astrophysics Data System (ADS)

Jones, J.; de Haan, S.; Vedel, H.

2011-12-01

The main purpose of E-GVAP is to deliver near real-time (NRT) ground based GNSS delay data for usage in operational meteorology. This involves the collection and processing of raw GNSS data to estimate zenith total delay (ZTD) and subsequent collection and distribution of ZTD data to European national meteorological services. Validation and quality control, production of 2D animated water vapour maps, development of best practices for GNSS data processing and data usage in Numerical Weather Prediction (NWP) models, are other important aspects. Furthermore there is a current push for more real-time observations which would have positive impacts in high both resolution NWP and for nowcasting applications. We present an overview of the current status of E-GVAP.

Explosion bomb measurements of ethanol-air laminar gaseous flame characteristics at pressures up to 1.4 MPa

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

Bradley, D.; Lawes, M.; Mansour, M.S.

2009-07-15

The principal burning characteristics of a laminar flame comprise the fuel vapour pressure, the laminar burning velocity, ignition delay times, Markstein numbers for strain rate and curvature, the stretch rates for the onset of flame instabilities and of flame extinction for different mixtures. With the exception of ignition delay times, measurements of these are reported and discussed for ethanol-air mixtures. The measurements were in a spherical explosion bomb, with central ignition, in the regime of a developed stable, flame between that of an under or over-driven ignition and that of an unstable flame. Pressures ranged from 0.1 to 1.4 MPa,more » temperatures from 300 to 393 K, and equivalence ratios were between 0.7 and 1.5. It was important to ensure the relatively large volume of ethanol in rich mixtures at high pressures was fully evaporated. The maximum pressure for the measurements was the highest compatible with the maximum safe working pressure of the bomb. Many of the flames soon became unstable, due to Darrieus-Landau and thermo-diffusive instabilities. This effect increased with pressure and the flame wrinkling arising from the instabilities enhanced the flame speed. Both the critical Peclet number and the, more rational, associated critical Karlovitz stretch factor were evaluated at the onset of the instability. With increasing pressure, the onset of flame instability occurred earlier. The measured values of burning velocity are expressed in terms of their variations with temperature and pressure, and these are compared with those obtained by other researchers. Some comparisons are made with the corresponding properties for iso-octane-air mixtures. (author)« less

Dislocations limited electronic transport in hydride vapour phase epitaxy grown GaN templates: A word of caution for the epitaxial growers

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

Chatterjee, Abhishek, E-mail: cabhishek@rrcat.gov.in; Khamari, Shailesh K.; Kumar, R.

2015-01-12

GaN templates grown by hydride vapour phase epitaxy (HVPE) and metal organic vapour phase epitaxy (MOVPE) techniques are compared through electronic transport measurements. Carrier concentration measured by Hall technique is about two orders larger than the values estimated by capacitance voltage method for HVPE templates. It is learnt that there exists a critical thickness of HVPE templates below which the transport properties of epitaxial layers grown on top of them are going to be severely limited by the density of charged dislocations lying at layer-substrate interface. On the contrary MOVPE grown templates are found to be free from such limitations.

Two-order-parameter description of liquid Al under five different pressures

NASA Astrophysics Data System (ADS)

Li, Y. D.; Hao, Qing-Hai; Cao, Qi-Long; Liu, C. S.

2008-11-01

In the present work, using the glue potential, the constant pressure molecular-dynamics simulations of liquid Al under five various pressures and a systematic analysis of the local atomic structures have been performed in order to test the two-order-parameter model proposed by Tanaka [Phys. Rev. Lett. 80, 5750 (1998)] originally for explaining the unusual behaviors of liquid water. The temperature dependence of the bond order parameter Q6 in liquid Al under five different pressures can be well fitted by the functional expression (Q6)/(1-Q6)=Q60exp((ΔE-PΔV)/(kBT)) which produces the energy gain ΔE and the volume change upon the formation of a locally favored structure: ΔE=0.025eV and ΔV=-0.27(Å)3 . ΔE is nearly equal to the difference between the average bond energy of the other type I bonds and the average bond energy of 1551 bonds (characterizing the icosahedronlike local structure); ΔV could be explained as the average volume occupied by one atom in icosahedra minus that occupied by one atom in other structures. With the obtained ΔE and ΔV , it is satisfactorily explained that the density of liquid Al displays a much weaker nonlinear dependence on temperature under lower pressures. So it is demonstrated that the behavior of liquid Al can be well described by the two-order-parameter model.

Inter-arm blood pressure difference in hospitalized elderly patients--is it consistent?

PubMed

Grossman, Alon; Weiss, Avraham; Beloosesky, Yichayaou; Morag-Koren, Nira; Green, Hefziba; Grossman, Ehud

2014-07-01

Inter-arm blood pressure difference (IAD) is recognized as a risk factor for cardiovascular mortality. Its reproducibility in the elderly is unknown. The authors determined the prevalence and reproducibility of IAD in hospitalized elderly patients. Blood pressure was measured simultaneously in both arms on two different days in elderly individuals hospitalized in a geriatric ward. The study included 364 elderly patients (mean age, 85±5 years). Eighty-four patients (23%) had systolic IAD >10 and 62 patients (17%) had diastolic IAD >10 mm Hg. A total of 319 patients had two blood pressure measurements. Systolic and diastolic IAD remained in the same category in 203 (64%) and 231 (72%) patients, respectively. Correlations of systolic and diastolic IAD between the two measurements were poor. Consistency was not affected by age, body mass index, comorbidities, or treatment. IAD is extremely common in hospitalized elderly patients, but, because of poor consistency, its clinical significance in this population is uncertain. ©2014 Wiley Periodicals, Inc.

[Atrio-ventricular pressure difference associated with mitral valve motion].

PubMed

Wang, L M; Mori, H; Minezaki, K; Shinozaki, Y; Okino, H

1990-05-01

Pressure difference (PD) across the mitral valve was analyzed by a computer-aided catheter system in dogs. Positive PD (PPD) was consistently traced in the initial phase of rapid filling. While heart rate (HR) was below 100 beat/min, a negative PD (NPD) followed the above PPD. In the period between the NPD and the 2nd PPD due to atrial contraction, PD was kept at zero, while LA and LV pressures were gradually elevated by pulmonary venous return. As HR exceeded 100, 2 positive peaks of PD merged into M-shaped or mono-peaked PD. Through higher inflow resistance produced by artificial mitral stenosis, PPD peak decayed without NPD. In mitral regurgitation with an acute volume overload, all of the PD amplitudes were exaggerated. Thus the quick reversal of PD suggested the effect in blood filling process across the mitral valve.

Drunk Bugs: Chronic Vapour Alcohol Exposure Induces Marked Changes in the Gut Microbiome in Mice

PubMed Central

Peterson, Veronica L.; Jury, Nicholas J.; Cabrera-Rubio, Raúl; Draper, Lorraine A.; Crispie, Fiona; Cotter, Paul D.; Dinan, Timothy G.; Holmes, Andrew; Cryan, John F.

2017-01-01

The gut microbiota includes a community of bacteria that and play an integral part in host health and biological processes. Pronounced and repeated findings have linked gut microbiome to stress, anxiety, and depression. Currently, however, there remains only a limited set of studies focusing on microbiota change in substance abuse, including alcohol use disorder. To date, no studies have investigated the impact of vapour alcohol administration on the gut microbiome. For research on gut microbiota and addiction to proceed, an understanding of how route of drug administration affects gut microbiota must first be established. Animal models of alcohol abuse have proven valuable for elucidating the biological processes involved in addiction and alcohol-related diseases. This is the first study to investigate the effect of vapour route of ethanol administration on gut microbiota in mice. Adult male C57BL/6J mice were exposed to 4 weeks of chronic intermittent vapourized ethanol (CIE, N=10) or air (Control, N=9). Faecal samples were collected at the end of exposure followed by 16S sequencing and bioinformatic analysis. Robust separation between CIE and Control was seen in the microbiome, as assessed by alpha (Shannon and Simpson index, p<0.05) and beta (ANOSIM, p<0.001) diversity, with a notable decrease in alpha diversity in CIE. These results demonstrate that CIE exposure markedly alters the gut microbiota in mice. Significant increases in genus Alistipes (p<0.001) and significant reductions in genra Clostridium IV and XIVb (Kruskal-Wallis, p<0.001), Dorea (Kruskal-Wallis, p<0.01), and Coprococcus (Kruskal-Wallis, p<0.01) were seen between CIE mice and Control. These findings support the viability of the CIE method for studies investigating the microbiota-gut-brain axis and align with previous research showing similar microbiota alterations in inflammatory states during alcoholic hepatitis and psychological stress. PMID:28161446

Drunk bugs: Chronic vapour alcohol exposure induces marked changes in the gut microbiome in mice.

PubMed

Peterson, Veronica L; Jury, Nicholas J; Cabrera-Rubio, Raúl; Draper, Lorraine A; Crispie, Fiona; Cotter, Paul D; Dinan, Timothy G; Holmes, Andrew; Cryan, John F

2017-04-14

The gut microbiota includes a community of bacteria that play an integral part in host health and biological processes. Pronounced and repeated findings have linked gut microbiome to stress, anxiety, and depression. Currently, however, there remains only a limited set of studies focusing on microbiota change in substance abuse, including alcohol use disorder. To date, no studies have investigated the impact of vapour alcohol administration on the gut microbiome. For research on gut microbiota and addiction to proceed, an understanding of how route of drug administration affects gut microbiota must first be established. Animal models of alcohol abuse have proven valuable for elucidating the biological processes involved in addiction and alcohol-related diseases. This is the first study to investigate the effect of vapour route of ethanol administration on gut microbiota in mice. Adult male C57BL/6J mice were exposed to 4 weeks of chronic intermittent vapourized ethanol (CIE, N=10) or air (Control, N=9). Faecal samples were collected at the end of exposure followed by 16S sequencing and bioinformatic analysis. Robust separation between CIE and Control was seen in the microbiome, as assessed by alpha (p<0.05) and beta (p<0.001) diversity, with a notable decrease in alpha diversity in CIE. These results demonstrate that CIE exposure markedly alters the gut microbiota in mice. Significant increases in genus Alistipes (p<0.001) and significant reductions in genra Clostridium IV and XIVb (p<0.001), Dorea (p<0.01), and Coprococcus (p<0.01) were seen between CIE mice and Control. These findings support the viability of the CIE method for studies investigating the microbiota-gut-brain axis and align with previous research showing similar microbiota alterations in inflammatory states during alcoholic hepatitis and psychological stress. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of plantar pressure distribution between three different shoes and three common movements in futsal.

PubMed

Teymouri, Meghdad; Halabchi, Farzin; Mirshahi, Maryam; Mansournia, Mohammad Ali; Mousavi Ahranjani, Ali; Sadeghi, Amir

2017-01-01

Analysis of in-shoe pressure distribution during sport-specific movements may provide a clue to improve shoe design and prevent injuries. This study compared the mean and the peak pressures over the whole foot and ten separate areas of the foot, wearing different shoes during specific movements. Nine male adult recreational futsal players performed three trials of three sport-specific movements (shuffle, sprint and penalty kick), while they were wearing three brands of futsal shoes (Adidas, Lotto and Tiger). Plantar pressures on dominant feet were collected using the F-SCAN system. Peak and mean pressures for whole foot and each separate area were extracted. For statistical analysis, the mean differences in outcome variables between different shoes and movements were estimated using random-effects regression model using STATA ver.10. In the average calculation of the three movements, the peak pressure on the whole foot in Adidas shoe was less than Lotto [8.8% (CI95%: 4.1-13.6%)] and Tiger shoes [11.8% (CI95%:7-16.7%)], (P<0.001). Also, the recorded peak pressure on the whole foot in penalty kick was 61.1% (CI95%: 56.3-65.9%) and 57.6% (CI95%: 52.8-62.3%) less than Shuffle and Sprint tests, respectively (P<0.001). Areas with the highest peak pressure during all 3 movements were not different between all shoes. This area was medial forefoot in cases of shuffle and sprint movements and medial heel in case of penalty kick.

Comparison of plantar pressure distribution between three different shoes and three common movements in futsal

PubMed Central

Teymouri, Meghdad; Mirshahi, Maryam; Mansournia, Mohammad Ali; Mousavi Ahranjani, Ali; Sadeghi, Amir

2017-01-01

Introduction Analysis of in-shoe pressure distribution during sport-specific movements may provide a clue to improve shoe design and prevent injuries. This study compared the mean and the peak pressures over the whole foot and ten separate areas of the foot, wearing different shoes during specific movements. Methods Nine male adult recreational futsal players performed three trials of three sport-specific movements (shuffle, sprint and penalty kick), while they were wearing three brands of futsal shoes (Adidas, Lotto and Tiger). Plantar pressures on dominant feet were collected using the F-SCAN system. Peak and mean pressures for whole foot and each separate area were extracted. For statistical analysis, the mean differences in outcome variables between different shoes and movements were estimated using random-effects regression model using STATA ver.10. Results In the average calculation of the three movements, the peak pressure on the whole foot in Adidas shoe was less than Lotto [8.8% (CI95%: 4.1–13.6%)] and Tiger shoes [11.8% (CI95%:7–16.7%)], (P<0.001). Also, the recorded peak pressure on the whole foot in penalty kick was 61.1% (CI95%: 56.3–65.9%) and 57.6% (CI95%: 52.8–62.3%) less than Shuffle and Sprint tests, respectively (P<0.001). Conclusion Areas with the highest peak pressure during all 3 movements were not different between all shoes. This area was medial forefoot in cases of shuffle and sprint movements and medial heel in case of penalty kick. PMID:29088278

Recent advances in measurement of the water vapour continuum in the far-infrared spectral region

NASA Astrophysics Data System (ADS)

Green, P. D.; Newman, S. M.; Beeby, R. J.; Murray, J. E.; Pickering, J. C.; Harries, J. E.

2012-06-01

We present a new derivation of the foreign-broadened water vapour continuum in the far-infrared (far-IR) pure rotation band between 24 μm and 120 μm (85-420 cm-1) from field data collected in flight campaigns of the Continuum Absorption by Visible and IR radiation and Atmospheric Relevance (CAVIAR) project with Imperial College's Tropospheric Airborne Fourier Transform Spectrometer (TAFTS) far-IR spectro-radiometer instrument onboard the Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft; and compare this new derivation with those recently published in the literature in this spectral band. This new dataset validates the current Mlawer-Tobin-Clough-Kneizys-Davies (MT-CKD) 2.5 model parametrization above 300 cm-1, but indicates the need to strengthen the parametrization below 300 cm-1, by up to 50 per cent at 100 cm-1. Data recorded at a number of flight altitudes have allowed measurements within a wide range of column water vapour environments, greatly increasing the sensitivity of this analysis to the continuum strength.

Computer simulation study of the nematic-vapour interface in the Gay-Berne model

NASA Astrophysics Data System (ADS)

Rull, Luis F.; Romero-Enrique, José Manuel

2017-06-01

We present computer simulations of the vapour-nematic interface of the Gay-Berne model. We considered situations which correspond to either prolate or oblate molecules. We determine the anchoring of the nematic phase and correlate it with the intermolecular potential parameters. On the other hand, we evaluate the surface tension associated to this interface. We find a corresponding states law for the surface tension dependence on the temperature, valid for both prolate and oblate molecules.

Growth of carbon nanotubes (CNTs) on metallic underlayers by diffusion plasma-enhanced chemical vapour deposition (DPECVD)

NASA Astrophysics Data System (ADS)

Kim, S. M.; Gangloff, L.

2009-10-01

Here, we demonstrate the low-temperature (480-612 °C) synthesis of carbon nanotubes (CNTs) on different metallic underlayers (i.e., NiV, Ir, Ag, Pt, W, and Ta) using diffusion (dc) plasma-enhanced (~20 W, -600 V) chemical vapour deposition (DPECVD). The catalyst used is bi-layered Fe/Al and the feedstock used is a mixture of C 2H 2 and NH 3 (1:4). The crucial component is the diffusion of radical ions and hydrogen generated such as H 2/H +/H 2+/NH 3+/CH 2+/C 2H 2+ (which are confirmed by in-situ mass spectroscopy) from the nozzle, where it is inserted for most effective plasma diffusion between a substrate and a gas distributor.

Left ventricular diastolic function in workers occupationally exposed to mercury vapour without clinical presentation of cardiac involvement

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

Poręba, Rafał, E-mail: sogood@poczta.onet.pl; Skoczyńska, Anna; Gać, Paweł

2012-09-15

The aim of the study was to evaluate left ventricular diastolic function in workers occupationally exposed to mercury vapour without clinical presentation of cardiac involvement. The studies included 115 workers (92 men and 23 women) occupationally exposed to mercury vapour without clinical presentation of cardiac involvement (mean age: 47.83 ± 8.29). Blood samples were taken to determine blood lipid profile, urine was collected to estimate mercury concentration (Hg-U) and echocardiographic examination was performed to evaluate diastolic function of the left ventricle. In the entire group of workers occupationally exposed to mercury vapour without clinical presentation of cardiac involvement, Spearman correlationsmore » analysis demonstrated the following significant linear relationships: between body mass index (BMI) and ratio of maximal early diastolic mitral flow velocity/early diastolic mitral annular velocity (E/E') (r = 0.32, p < 0.05), between serum HDL concentration and E/E' (r = − 0.22, p < 0.05), between Hg-U and E/E' (r = 0.35, p < 0.05), between Hg-U and isovolumetric relaxation time (IVRT') (r = 0.41, p < 0.05), between Hg-U and ratio of maximal early diastolic mitral flow velocity/maximal late diastolic mitral flow velocity (E/A) (r = − 0.31, p < 0.05) and between serum HDL concentration and E/A (r = 0.43, p < 0,05). In logistic regression analysis it as shown that independent factors of left ventricular diastolic dysfunction risk in the study group included a higher urine mercury concentration, a higher value of BMI and a lower serum HDL concentration (OR{sub Hg}-{sub U} = 1.071, OR{sub BMI} = 1.200, OR{sub HDL} = 0.896, p < 0.05). Summing up, occupational exposure to mercury vapour may be linked to impaired left ventricular diastolic function in workers without clinical presentation of cardiac involvement. -- Highlights: ► Study aimed at evaluation of LVDD in workers occupationally exposed to Hg. ► There was significant linear

Influence of Individual Differences on the Calculation Method for FBG-Type Blood Pressure Sensors

PubMed Central

Koyama, Shouhei; Ishizawa, Hiroaki; Fujimoto, Keisaku; Chino, Shun; Kobayashi, Yuka

2016-01-01

In this paper, we propose a blood pressure calculation and associated measurement method that by using a fiber Bragg grating (FBG) sensor. There are several points at which the pulse can be measured on the surface of the human body, and when a FBG sensor located at any of these points, the pulse wave signal can be measured. The measured waveform is similar to the acceleration pulse wave. The pulse wave signal changes depending on several factors, including whether or not the individual is healthy and/or elderly. The measured pulse wave signal can be used to calculate the blood pressure using a calibration curve, which is constructed by a partial least squares (PLS) regression analysis using a reference blood pressure and the pulse wave signal. In this paper, we focus on the influence of individual differences from calculated blood pressure based on each calibration curve. In our study, the calculated blood pressure from both the individual and overall calibration curves were compared, and our results show that the calculated blood pressure based on the overall calibration curve had a lower measurement accuracy than that based on an individual calibration curve. We also found that the influence of the individual differences on the calculated blood pressure when using the FBG sensor method were very low. Therefore, the FBG sensor method that we developed for measuring the blood pressure was found to be suitable for use by many people. PMID:28036015

Influence of Individual Differences on the Calculation Method for FBG-Type Blood Pressure Sensors.

PubMed

Koyama, Shouhei; Ishizawa, Hiroaki; Fujimoto, Keisaku; Chino, Shun; Kobayashi, Yuka

2016-12-28

In this paper, we propose a blood pressure calculation and associated measurement method that by using a fiber Bragg grating (FBG) sensor. There are several points at which the pulse can be measured on the surface of the human body, and when a FBG sensor located at any of these points, the pulse wave signal can be measured. The measured waveform is similar to the acceleration pulse wave. The pulse wave signal changes depending on several factors, including whether or not the individual is healthy and/or elderly. The measured pulse wave signal can be used to calculate the blood pressure using a calibration curve, which is constructed by a partial least squares (PLS) regression analysis using a reference blood pressure and the pulse wave signal. In this paper, we focus on the influence of individual differences from calculated blood pressure based on each calibration curve. In our study, the calculated blood pressure from both the individual and overall calibration curves were compared, and our results show that the calculated blood pressure based on the overall calibration curve had a lower measurement accuracy than that based on an individual calibration curve. We also found that the influence of the individual differences on the calculated blood pressure when using the FBG sensor method were very low. Therefore, the FBG sensor method that we developed for measuring the blood pressure was found to be suitable for use by many people.

[Measuring the blood pressure in both arms is of little use; longitudinal study into blood pressure differences between both arms and its reproducibility in patients with diabetes mellitus type 2].

PubMed

Kleefstra, N; Houweling, S T; Meyboom-de Jong, B; Bilo, H J G

2007-07-07

To determine the prevalence of inter-arm blood pressure differences > 10 mmHg in patients with diabetes mellitus type 2 (DM2) and to determine whether these differences are consistent over time. Descriptive. In an evaluation study of 169 DM2 patients from 5 general practices in 2003 and 2004, different methods of oscillatory measurement were used to investigate inter-arm blood pressure differences > 10 mmHg systolic or diastolic. These methods were: one measurement in each arm non-simultaneously (method A), one measurement simultaneously (B) and the mean of two simultaneous measurements (C). With method A an inter-arm blood pressure difference was found in 33% of patients. This percentage diminished to 9 with method C. In 44% (n = 7) of the patients in whom method C detected a relevant blood pressure difference, this difference was not found with method A. In 79% of patients the inter-arm blood pressure difference was not reproduced after one year. In daily practice, one non-simultaneous blood pressure measurement in each arm (method A) was of little value for identification of patients with inter-arm blood pressure differences. The reproducibility was poor one year later. Bilateral blood pressure measurement is therefore of little value.

Generation of High Resolution Water Vapour Fields from GPS Observations and Integration With ECMWF and MODIS

NASA Astrophysics Data System (ADS)

Yu, C.; Li, Z.; Penna, N. T.

2016-12-01

Precipitable water vapour (PWV) can be routinely retrieved from ground-based GPS arrays in all-weather conditions and also in real-time. But to provide dense spatial coverage maps, for example for calibrating SAR images, for correcting atmospheric effects in Network RTK GPS positioning and which may be used for numerical weather prediction, the pointwise GPS PWV measurements must be interpolated. Several previous interpolation studies have addressed the importance of the elevation dependency of water vapour, but it is often a challenge to separate elevation-dependent tropospheric delays from turbulent components. We present a tropospheric turbulence iterative decomposition model that decouples the total PWV into (i) a stratified component highly correlated with topography which therefore delineates the vertical troposphere profile, and (ii) a turbulent component resulting from disturbance processes (e.g., severe weather) in the troposphere which trigger uncertain patterns in space and time. We will demonstrate that the iterative decoupled interpolation model generates improved dense tropospheric water vapour fields compared with elevation dependent models, with similar accuracies obtained over both flat and mountainous terrain, as well as for both inland and coastal areas. We will also show that our GPS-based model may be enhanced with ECMWF zenith tropospheric delay and MODIS PWV, producing multi-data sources high temporal-spatial resolution PWV fields. These fields were applied to Sentinel-1 SAR interferograms over the Los Angeles region, for which a maximum noise reduction due to atmosphere artifacts reached 85%. The results reveal that the turbulent troposphere noise, especially those in a SAR image, often occupy more than 50% of the total zenith tropospheric delay and exert systematic, rather than random patterns.

Vapour discharges on Nevado del Ruiz during the recent activity: Clues on the composition of the deep hydrothermal system and its effects on thermal springs

NASA Astrophysics Data System (ADS)

Federico, Cinzia; Inguaggiato, Salvatore; Chacón, Zoraida; Londoño, John Makario; Gil, Edwing; Alzate, Diego

2017-10-01

The Nevado del Ruiz volcano is considered one of the most active volcanoes in Colombia, which can potentially threaten approximately 600,000 inhabitants. The existence of a glacier and several streams channelling in some main rivers, flowing downslope, increases the risk for the population living on the flank of the volcano in case of unrest, because of the generation of lahars and mudflows. Indeed, during the November 1985 subplinian eruption, a lahar generated by the sudden melting of the glacier killed twenty thousand people in the town of Armero. Moreover, the involvement of the local hydrothermal system has produced in the past phreatic and phreatomagmatic activity, as occurred in 1989. Therefore, the physico-chemical conditions of the hydrothermal system as well as its contribution to the shallow thermal groundwater and freshwater in terms of enthalpy and chemicals require a close monitoring. The phase of unrest occurred since 2010 and culminated with an eruption in 2012, after several years of relative stability, still maintains a moderate alert, as required by the high seismicity and SO2 degassing. In October 2013, a sampling campaign has been performed on thermal springs and stream water, located at 2600-5000 m of elevation on the slope of Nevado del Ruiz, analyzed for water chemistry and stable isotopes. Some of these waters are typically steam-heated (low pH and high sulfate content) by the vapour probably separating from a zoned hydrothermal system. By applying a model of steam-heating, based on mass and enthalpy balances, we have estimated the mass rate of hydrothermal steam discharging in the different springs. The composition of the hottest thermal spring (Botero Londono) is probably representative of a marginal part of the hydrothermal system, having a temperature of 250 °C and low salinity (Cl 1500 mg/l), which suggest, along with the retrieved isotope composition, a chiefly meteoric origin. The vapour discharged at the steam vent "Nereidas" (3600

Extremely fast and highly selective detection of nitroaromatic explosive vapours using fluorescent polymer thin films.

PubMed

Demirel, Gokcen Birlik; Daglar, Bihter; Bayindir, Mehmet

2013-07-14

A novel sensing material based on pyrene doped polyethersulfone worm-like structured thin film is developed using a facile technique for detection of nitroaromatic explosive vapours. The formation of π-π stacking in the thin fluorescent film allows a highly sensitive fluorescence quenching which is detectable by the naked eye in a response time of a few seconds.

Prediction of Three-Dimensional Downward Flame Spread Characteristics over Poly(methyl methacrylate) Slabs in Different Pressure Environments.

PubMed

Zhao, Kun; Zhou, Xiao-Dong; Liu, Xue-Qiang; Lu, Lei; Wu, Zhi-Bo; Peng, Fei; Ju, Xiao-Yu; Yang, Li-Zhong

2016-11-22

The present study is aimed at predicting downward flame spread characteristics over poly(methyl methacrylate) (PMMA) with different sample dimensions in different pressure environments. Three-dimensional (3-D) downward flame spread experiments on free PMMA slabs were conducted at five locations with different altitudes, which provide different pressures. Pressure effects on the flame spread rate, profile of pyrolysis front and flame height were analyzed at all altitudes. The flame spread rate in the steady-state stage was calculated based on the balance on the fuel surface and fuel properties. Results show that flame spread rate increases exponentially with pressure, and the exponent of pressure further shows an increasing trend with the thickness of the sample. The angle of the pyrolysis front emerged on sample residue in the width direction, which indicates a steady-burning stage, varies clearly with sample thicknesses and ambient pressures. A global non-dimensional equation was proposed to predict the variation tendency of the angle of the pyrolysis front with pressure and was found to fit well with the measured results. In addition, the dependence of average flame height on mass burning rate, sample dimension and pressure was proposed based on laminar diffusion flame theory. The fitted exponent of experimental data is 1.11, which is close to the theoretical value.

Water Vapour Mixing Ratio Measurements in Potenza in the Frame of the International Network for the Detection of Atmospheric Composition Change - NDACC

NASA Astrophysics Data System (ADS)

De Rosa, Benedetto; Di Girolamo, Paolo; Summa, Donato; Stelitano, Dario; Mancini, Ignazio

2016-06-01

In November 2012 the University of BASILicata Raman Lidar system (BASIL) was approved to enter the International Network for the Detection of Atmospheric Composition Change (NDACC). This network includes more than 70 high-quality, remote-sensing research stations for observing and understanding the physical and chemical state of the upper troposphere and stratosphere and for assessing the impact of stratosphere changes on the underlying troposphere and on global climate. As part of this network, more than thirty groundbased Lidars deployed worldwide are routinely operated to monitor atmospheric ozone, temperature, aerosols, water vapour, and polar stratospheric clouds. In the frame of NDACC, BASIL performs measurements on a routine basis each Thursday, typically from local noon to midnight, covering a large portion of the daily cycle. Measurements from BASIL are included in the NDACC database both in terms of water vapour mixing ratio and temperature. This paper illustrates some measurement examples from BASIL, with a specific focus on water vapour measurements, with the goal to try and characterize the system performances.

Vapour breakthrough behaviour of carbon tetrachloride - A simulant for chemical warfare agent on ASZMT carbon: A comparative study with whetlerite carbon

NASA Astrophysics Data System (ADS)

Srivastava, Avanish Kumar; Shah, Dilip K.; Mahato, T. H.; Roy, A.; Yadav, S. S.; Srivas, S. K.; Singh, Beer

2013-06-01

ASZMT and whetlerite carbon was prepared by impregnation of active carbon with ammonical salts of Cu (II), Ag (I), Zn (II), Mo (VI), TEDA and Cu (II), Ag (I), Cr (VI), NaOH, C5H5N respectively using incipient wetness technique. Thereafter, impregnated carbon systems were characterized using scanning electron microscopy, energy dispersive X-ray, atomic absorption spectroscopy, thermogravimetry and surface characterization techniques. Impregnated carbon systems were evaluated under dynamic conditions against carbon tetrachloride (CCl4) vapour that was used as a simulant for the persistent chemical warfare agents for testing breakthrough times of filter cartridges and canisters of gas masks in the national approval test of respirators. The protective potential of ASZMT carbon was compared with the whetlerite carbon which is presently used in NBC filtration system. The effect of CCl4 concentration, test flow rate, temperature and relative humidity on the breakthrough behaviour of the impregnated carbon systems has also been studied. The study clearly indicated that the whetlerite carbon possessed breakthrough time greater than ASZMT carbon. However, ASZMT carbon provided adequate protection against CCl4 vapours and can be used as an alternative to whetlerite carbon that contain Cr(VI), which is reported to be carcinogenic and having lesser shelf life. The study indicated the breakthrough time of impregnated carbon systems were found to decrease with the increase of the CCl4 concentration and flow rate. The variation in temperature and relative humidity did not significantly affect the breakthrough behaviour of impregnated carbon systems at high vapour concentration of CCl4 whereasbreak through time of impregnated carbon systems reduced by an increase of relative humidity at low CCl4 vapour concentration.

Effect of Saturation Pressure Difference on Metal-Silicide Nanopowder Formation in Thermal Plasma Fabrication.

PubMed

Shigeta, Masaya; Watanabe, Takayuki

2016-03-07

A computational investigation using a unique model and a solution algorithm was conducted, changing only the saturation pressure of one material artificially during nanopowder formation in thermal plasma fabrication, to highlight the effects of the saturation pressure difference between a metal and silicon. The model can not only express any profile of particle size-composition distribution for a metal-silicide nanopowder even with widely ranging sizes from sub-nanometers to a few hundred nanometers, but it can also simulate the entire growth process involving binary homogeneous nucleation, binary heterogeneous co-condensation, and coagulation among nanoparticles with different compositions. Greater differences in saturation pressures cause a greater time lag for co-condensation of two material vapors during the collective growth of the metal-silicide nanopowder. The greater time lag for co-condensation results in a wider range of composition of the mature nanopowder.

Immediate effects of different schedules of somatostatin on portal pressure in patients with liver cirrhosis.

PubMed

Zhang, C; Xu, J-M; Kong, D-R; Min, X-K; Chen, R

2013-06-01

Somatostatin (SST) is used for the treatment of acute variceal bleeding based on its ability to decrease portal pressure and collateral blood flow. To date, no studies have focused on the immediate-early effects (between 1 and 30 min) of SST. The aim of this study was to compare the efficacy of different schedules of SST therapy with placebo on portal pressure in patients with portal hypertension treated with portal-azygous disconnection and to test whether an increase in bolus or infusion dose can improve the clinical efficacy of SST therapy.   Patients were treated with four different schedules: (a) standard dose (n = 11): one 250 μg bolus + a continuous infusion of 250 μg/h; (b) medium dose (n = 10): 500 μg bolus + a continuous infusion of 250 μg/h; (c) high dose (n = 10): 250 μg bolus + a continuous infusion of 500 μg/h; (d) control (n = 10): an injection of placebo (saline) followed by a placebo infusion. Following SST or placebo administration, portal pressure, central venous pressure (CVP), systemic blood pressure and heart rate (HR) were measured at 1, 3, 5, 7, 10 and 30 min.   The three schedules of SST induced a marked, rapid and highly significant decrease in portal pressure. The decline in portal pressure was moderate at 1 min (P < 0·040), achieved a peak effect at 5 min (P < 0·009) and remained decreased at 30 min. The effect of SST on portal pressure was significantly greater than placebo from 1 min after administration. There were no significant differences in portal pressure decrease between the three schedules of SST. The three schedules of SST and the placebo schedule did not induce significant changes in HR, systemic blood pressure and CVP.   This study shows that SST is effective in decreasing portal pressure within 30 min of administration in patients with liver cirrhosis. The clinical schedule used in this study was reasonable and safe. © 2013 Blackwell Publishing Ltd.

[Comparison of different continuous positive airway pressure titration methods for obstructive sleep apnea hypopnea syndrome].

PubMed

Li, Jingjing; Ye, Jingying; Zhang, Peng; Kang, Dan; Cao, Xin; Zhang, Yuhuan; Ding, Xiu; Zheng, Li; Li, Hongguang; Bian, Qiuli

2014-10-01

To explore whether there were differences between the results of automatic titration and the results of manual titration for positive airway pressure treatment in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and its influencing factors, the results might provide a theoretical basis for the rational use of two pressure titration methods. Sixty one patients with OSAHS were included in this study. All patients underwent a manual titration and an automatic titration within one week. The clinical informations, polysomnography data, and the results of both two titration of all patients were obtained for analysis. The overall apnea/hypopnea index was (63.1 ± 17.7)/h, with a range of 14.9/h to 110.4/h. The treatment pressure of manual titration was (8.4 ± 2.1) cmH(2)O, which was significantly lower than the treatment pressure of automatic titration, (11.5 ± 2.7) cmH(2)O (t = -9.797, P < 0.001). After using a ΔP of 3 cmH(2)O for the cutoff value (ΔP was defined as the difference of automatic titration and manual titration), it was found that the pressure of automatic titration was significantly higher in patients with a ΔP > 3 cmH(2)O than in patients with a ΔP ≤ 3 cmH(2)O, which was (13.3 ± 2.3) cmH(2)O vs (10.0 ± 2.0) cmH(2)O (t = -6.159, P < 0.001). However, there were no differences for the pressure of manual titration between these two groups, which was (8.6 ± 2.4) cmH(2)O vs (8.3 ± 2.0)cmH(2)O (P > 0.05). There was no significant difference in age, body mass index, neck circumference, abdomen circumference, apnea hypopnea index, and arterial oxygen saturation between these two groups. The treatment pressure of automatic titration is usually higher than that of manual titration. For patients with a high treatment pressure which is derived from automatic titration, a suggestion about manual titration could be given to decrease the potential treatment pressure of continuous positive airway pressure, which may be helpful in improving the

Water vapour foreign-continuum absorption in near-infrared windows from laboratory measurements.

PubMed

Ptashnik, Igor V; McPheat, Robert A; Shine, Keith P; Smith, Kevin M; Williams, R Gary

2012-06-13

For a long time, it has been believed that atmospheric absorption of radiation within wavelength regions of relatively high infrared transmittance (so-called 'windows') was dominated by the water vapour self-continuum, that is, spectrally smooth absorption caused by H(2)O--H(2)O pair interaction. Absorption due to the foreign continuum (i.e. caused mostly by H(2)O--N(2) bimolecular absorption in the Earth's atmosphere) was considered to be negligible in the windows. We report new retrievals of the water vapour foreign continuum from high-resolution laboratory measurements at temperatures between 350 and 430 K in four near-infrared windows between 1.1 and 5 μm (9000-2000 cm(-1)). Our results indicate that the foreign continuum in these windows has a very weak temperature dependence and is typically between one and two orders of magnitude stronger than that given in representations of the continuum currently used in many climate and weather prediction models. This indicates that absorption owing to the foreign continuum may be comparable to the self-continuum under atmospheric conditions in the investigated windows. The calculated global-average clear-sky atmospheric absorption of solar radiation is increased by approximately 0.46 W m(-2) (or 0.6% of the total clear-sky absorption) by using these new measurements when compared with calculations applying the widely used MTCKD (Mlawer-Tobin-Clough-Kneizys-Davies) foreign-continuum model.

Combining single source chemical vapour deposition precursors to explore the phase space of titanium oxynitride thin films.

PubMed

Rees, Kelly; Lorusso, Emanuela; Cosham, Samuel D; Kulak, Alexander N; Hyett, Geoffrey

2018-02-14

In this paper we report on a novel chemical vapour deposition approach to the formation and control of composition of mixed anion materials, as applied to titanium oxynitride thin films. The method used is the aerosol assisted chemical vapour deposition (AACVD) of a mixture of single source precursors. To explore the titanium-oxygen-nitrogen system the single source precursors selected were tetrakis(dimethylamido) titanium and titanium tetraisopropoxide which individually are precursors to thin films of titanium nitride and titanium dioxide respectively. However, by combining these precursors in specific ratios in a series of AACVD reactions at 400 °C, we are able to deposit thin films of titanium oxynitride with three different structure types and a wide range of compositions. Using this precursor system we can observe films of nitrogen doped anatase, with 25% anion doping of nitrogen; a new composition of pseudobrookite titanium oxynitride with a composition of Ti 3 O 3.5 N 1.5 , identified as being a UV photocatalyst; and rock-salt titanium oxynitride in the range TiO 0.41 N 0.59 to TiO 0.05 N 0.95 . The films were characterised using GIXRD, WDX and UV-vis spectroscopy, and in the case of the pseudobrookite films, assessed for photocatalytic activity. This work shows that a so-called dual single-source CVD approach is an effective method for the deposition of ternary mixed anion ceramic films through simple control of the ratio of the precursors, while keeping all other experimental parameters constant.

Surface thermodynamics of planar, cylindrical, and spherical vapour-liquid interfaces of water

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

Lau, Gabriel V.; Müller, Erich A.; Jackson, George

2015-03-21

The test-area (TA) perturbation approach has been gaining popularity as a methodology for the direct computation of the interfacial tension in molecular simulation. Though originally implemented for planar interfaces, the TA approach has also been used to analyze the interfacial properties of curved liquid interfaces. Here, we provide an interpretation of the TA method taking the view that it corresponds to the change in free energy under a transformation of the spatial metric for an affine distortion. By expressing the change in configurational energy of a molecular configuration as a Taylor expansion in the distortion parameter, compact relations are derivedmore » for the interfacial tension and its energetic and entropic components for three different geometries: planar, cylindrical, and spherical fluid interfaces. While the tensions of the planar and cylindrical geometries are characterized by first-order changes in the energy, that of the spherical interface depends on second-order contributions. We show that a greater statistical uncertainty is to be expected when calculating the thermodynamic properties of a spherical interface than for the planar and cylindrical cases, and the evaluation of the separate entropic and energetic contributions poses a greater computational challenge than the tension itself. The methodology is employed to determine the vapour-liquid interfacial tension of TIP4P/2005 water at 293 K by molecular dynamics simulation for planar, cylindrical, and spherical geometries. A weak peak in the curvature dependence of the tension is observed in the case of cylindrical threads of condensed liquid at a radius of about 8 Å, below which the tension is found to decrease again. In the case of spherical drops, a marked decrease in the tension from the planar limit is found for radii below ∼ 15 Å; there is no indication of a maximum in the tension with increasing curvature. The vapour-liquid interfacial tension tends towards the planar limit

Selective Pressures Explain Differences in Flower Color among Gentiana lutea Populations.

PubMed

Sobral, Mar; Veiga, Tania; Domínguez, Paula; Guitián, Javier A; Guitián, Pablo; Guitián, José M

2015-01-01

Flower color variation among plant populations might reflect adaptation to local conditions such as the interacting animal community. In the northwest Iberian Peninsula, flower color of Gentiana lutea varies longitudinally among populations, ranging from orange to yellow. We explored whether flower color is locally adapted and the role of pollinators and seed predators as agents of selection by analyzing the influence of flower color on (i) pollinator visitation rate and (ii) escape from seed predation and (iii) by testing whether differences in pollinator communities correlate with flower color variation across populations. Finally, (iv) we investigated whether variation in selective pressures explains flower color variation among 12 G. lutea populations. Flower color influenced pollinator visits and differences in flower color among populations were related to variation in pollinator communities. Selective pressures on flower color vary among populations and explain part of flower color differences among populations of G. lutea. We conclude that flower color in G. lutea is locally adapted and that pollinators play a role in this adaptation.

Selective Pressures Explain Differences in Flower Color among Gentiana lutea Populations

PubMed Central

Domínguez, Paula; Guitián, Javier A.; Guitián, Pablo; Guitián, José M.

2015-01-01

Flower color variation among plant populations might reflect adaptation to local conditions such as the interacting animal community. In the northwest Iberian Peninsula, flower color of Gentiana lutea varies longitudinally among populations, ranging from orange to yellow. We explored whether flower color is locally adapted and the role of pollinators and seed predators as agents of selection by analyzing the influence of flower color on (i) pollinator visitation rate and (ii) escape from seed predation and (iii) by testing whether differences in pollinator communities correlate with flower color variation across populations. Finally, (iv) we investigated whether variation in selective pressures explains flower color variation among 12 G. lutea populations. Flower color influenced pollinator visits and differences in flower color among populations were related to variation in pollinator communities. Selective pressures on flower color vary among populations and explain part of flower color differences among populations of G. lutea. We conclude that flower color in G. lutea is locally adapted and that pollinators play a role in this adaptation. PMID:26172378

Ethnic Differences in Physical Fitness, Blood Pressure and Blood Chemistry in Women (AGES 20-63)

NASA Technical Reports Server (NTRS)

Ayers, G. W.; Wier, L. T.; Jackson, A. S.; Stuteville, J. E.; Keptra, Sean (Technical Monitor)

1999-01-01

This study examined the role of ethnicity on the aerobic fitness, blood pressure, and selected blood chemistry values of women. One hundred twenty-four females (mean age 41.37 +/- 9.0) were medically Examined at the NASA/Johnson Space Center occupational health clinic. Ethnic groups consisted of 23 Black (B), 18 Hispanic (H) and 83 Non-minority (NM). Each woman had a maximum Bruce treadmill stress test (RER greater than or = 1.1) and a negative ECG. Indirect calorimetry, skinfolds, self-report physical activity (NASA activity scale), seated blood pressure, and blood chemistry panel determined VO2max, percent fat, level of physical activity, blood pressure and blood chemistry values. ANOVA revealed that the groups did not differ (p greater than 0.05) in age, VO2 max, weight, percent fat, level of physical activity, total cholesterol, or HDL-C. However, significant differences (p greater than 0.05) were noted in BMI, diastolic blood pressure, and blood chemistries. BMI was 3.17 higher in H than in NM; resting diastolic pressures were 5.69 and 8.05 mmHg. lower in NM and H than in B; triglycerides were 48.07 and 37.21 mg/dl higher in H than in B and NM; hemoglobin was .814 gm/dl higher in NM than B; fasting blood sugar was 15.41 mg/dl higher in H than NM; The results of this study showed that ethnic groups differed in blood pressure and blood chemistry values but not aerobic fitness or physical activity. There was an ethnic difference in BMI but not percent fat.

Effect of Saturation Pressure Difference on Metal–Silicide Nanopowder Formation in Thermal Plasma Fabrication

PubMed Central

Shigeta, Masaya; Watanabe, Takayuki

2016-01-01

A computational investigation using a unique model and a solution algorithm was conducted, changing only the saturation pressure of one material artificially during nanopowder formation in thermal plasma fabrication, to highlight the effects of the saturation pressure difference between a metal and silicon. The model can not only express any profile of particle size–composition distribution for a metal–silicide nanopowder even with widely ranging sizes from sub-nanometers to a few hundred nanometers, but it can also simulate the entire growth process involving binary homogeneous nucleation, binary heterogeneous co-condensation, and coagulation among nanoparticles with different compositions. Greater differences in saturation pressures cause a greater time lag for co-condensation of two material vapors during the collective growth of the metal–silicide nanopowder. The greater time lag for co-condensation results in a wider range of composition of the mature nanopowder. PMID:28344300

MEDUSA (Martian Environmental DUst Systematic Analyser) for the monitoring of the Martian atmospheric dust and water vapour

NASA Astrophysics Data System (ADS)

Colangeli, L.; Battaglia, R.; della Corte, V.; Esposito, F.; Ferrini, G.; Mazzotta Epifani, E.; Palomba, E.; Palumbo, P.; Panizza, A.; Rotundi, A.

2004-03-01

The knowledge of Martian airborne dust properties and about mechanisms of dust settling/raising to/from the surface are important to determine climate and surface evolution on Mars. Water is an important tracer of climatic changes on long time-scales and is strictly related to the presence of life forms. The study in situ of dust and water vapour properties and evolution in Martian atmosphere is useful to trace back the planet climate, also in function of life form development. This investigation is also appropriate in preparation to future manned exploration of the planet (in relation to hazardous conditions). In this work we discuss the concept of the MEDUSA (Martian Environmental Dust Analyser) experiment that is designed to provide data on grain size and mass distribution, number density, velocity and scattering properties and on water vapour concentration. The instrument is a multisensor system based on optical and impact detection of grains, coupled with cumulative deposition sensors.

Effect of different body postures on the pressures generated during an L-1 maneuver.

PubMed

Williams, C A; Lind, A R; Wiley, R L; Douglas, J E; Miller, G

1988-10-01

Changes in blood pressure, intrathoracic pressure, heart rate and the electromyographic activity of various muscle groups were determined while nine male subjects performed 15-s L-1 straining maneuvers at four spine-to-thigh angles (70, 84, 94, and 105 degrees) and two seatback angles (30 and 60 degrees). There was no significant difference between the changes in these variables due to the different body positions. At the onset of the L-1, arterial pressure immediately increased to 195 +/- 5 mm Hg, but fell progressively during the next 5 s to 160 +/- 5 mm Hg. It remained constant during the next 5 s of the maneuver and then recovered to 180 +/- mm Hg during the last 5 s of the maneuver. Esophageal pressure followed essentially the same pattern of response, but heart rate progressively increased during the entire L-1. No one muscle group was utilized more than another. Inflation of an anti-G suit to 4 PSI had no effect on the variables measured. Generation of high arterial pressures during L-1 maneuvers is transitory and not affected either positively or negatively by altering subject body position.

Age-related, interindividual, and right/left differences in anterior-posterior foot pressure ratio in preschool children

PubMed Central

2013-01-01

Background This study aimed to examine age-related, interindividual, and right/left differences in anterior-posterior foot pressure ratio in 764 preschool children (364 boys and 400 girls) aged 3.5-6.5 years. Methods Subjects maintained an upright standing posture for 10 seconds on the Footview Clinic, an instrument designed to calculate the anterior-posterior foot pressure ratio. The ratio of anterior foot pressure in each subject’s right and left feet was selected as a variable, and the mean of a 10 s measurement was used for analysis. Results The ratio of anterior foot pressure was significantly larger in the right foot than in the left foot. With regard to age, the ratio of anterior foot pressure was significantly larger in children aged over 4.5 years than in children aged 3.5 years. It was also larger in children aged 6 and 6.5 years than in children aged 4 years. Interindividual differences in variables were large, and coefficients of variance were highest in children aged 3.5 years and lowest in children aged 6.5 years. Conclusions In conclusion, anterior foot pressure increases with age in preschool children. Interindividual differences in anterior foot pressure are large and tend to decrease with age. Furthermore, the anterior foot pressure is slightly higher in the right foot than in the left foot. These results will be useful for various studies, such as examining relationships between the anterior-posterior foot pressure ratio and factors, such as untouched toes, physical fitness, and level of exercise. PMID:23601375

Different Selection Pressures Give Rise to Distinct Ethnic Phenomena

PubMed Central

Moya, Cristina; Boyd, Robert

2015-01-01

Many accounts of ethnic phenomena imply that processes such as stereotyping, essentialism, ethnocentrism, and intergroup hostility stem from a unitary adaptation for reasoning about groups. This is partly justified by the phenomena’s co-occurrence in correlational studies. Here we argue that these behaviors are better modeled as functionally independent adaptations that arose in response to different selection pressures throughout human evolution. As such, different mechanisms may be triggered by different group boundaries within a single society. We illustrate this functionalist framework using ethnographic work from the Quechua-Aymara language boundary in the Peruvian Altiplano. We show that different group boundaries motivate different ethnic phenomena. For example, people have strong stereotypes about socioeconomic categories, which are not cooperative units, whereas they hold fewer stereotypes about communities, which are the primary focus of cooperative activity. We also show that, despite the cross-cultural importance of ethnolinguistic boundaries, the Quechua-Aymara linguistic distinction does not strongly motivate any of these intergroup processes. PMID:25731969

A high-resolution extraterrestrial solar spectrum and water vapour continuum at near infrared wavelengths from ground-based spectrometer measurements

NASA Astrophysics Data System (ADS)

Menang, K. P.

A high resolution extraterrestrial solar spectrum (CAVIAR solar spectrum) and water vapour continuum have been derived in near infrared windows from 2000-10000 cm-1 (105μm), by applying the Langley technique to calibrated ground-based high-resolution Fourier transform spectrometer measurements, made under clear-sky conditions. The effect of the choice of an extraterrestrial solar spectrum for radiative transfer calculations of clear-sky absorption and heating rates in the near infrared was also studied. There is a good agreement between the solar lines strengths and positions of the CAVIAR solar spectrum and those from both high-resolution satellite and ground-based measurements in their regions of spectral overlap. However, there are significant differences between the structure of the CAVIAR solar spectrum and spectra from models. Many of the detected lines are missing from widely-used modelled extraterrestrial solar spectrum. The absolute level and hence wavenumber-integrated solar irradiance of the CAVIAR solar spectrum was also found to be 8% lower than the satellite-based Thuillier et al spectra from 5200-10000 cm-1. Using different extraterrestrial solar spectra for radiative transfer calculations in the near infrared led to differences of up to about 11 W m-2 (8.2%) in the absorbed solar irradiance while the tropospheric and stratospheric heating rates could respectively differ by up to about 0.13K day-1 (8.1%) and 0.19 K day-1 (7.6%) for an overhead Sun and mid-latitude summer atmosphere. This work has shown that the widely-used empirically modelled continuum may be underestimating the strength of the water vapour continuum from 2000-10000 cm-1, with the derived continuum up to more than 2 orders of magnitude stronger at some wavenumbers in the windows. The derived continuum is also stronger than that implied by laboratory measurements, by a factor of up to 40 in some spectral regions.

Competition for water vapour results in suppression of ice formation in mixed-phase clouds

NASA Astrophysics Data System (ADS)

Simpson, Emma L.; Connolly, Paul J.; McFiggans, Gordon

2018-05-01

The formation of ice in clouds can initiate precipitation and influence a cloud's reflectivity and lifetime, affecting climate to a highly uncertain degree. Nucleation of ice at elevated temperatures requires an ice nucleating particle (INP), which results in so-called heterogeneous freezing. Previously reported measurements for the ability of a particle to nucleate ice have been made in the absence of other aerosol which will act as cloud condensation nuclei (CCN) and are ubiquitous in the atmosphere. Here we show that CCN can outcompete INPs for available water vapour thus suppressing ice formation, which has the potential to significantly affect the Earth's radiation budget. The magnitude of this suppression is shown to be dependent on the mass of condensed water required for freezing. Here we show that ice formation in a state-of-the-art cloud parcel model is strongly dependent on the criteria for heterogeneous freezing selected from those previously hypothesised. We have developed an alternative criteria which agrees well with observations from cloud chamber experiments. This study demonstrates the dominant role that competition for water vapour can play in ice formation, highlighting both a need for clarity in the requirements for heterogeneous freezing and for measurements under atmospherically appropriate conditions.

Emergence of ethnic differences in blood pressure in adolescence: the determinants of adolescent social well-being and health study.

PubMed

Harding, Seeromanie; Whitrow, Melissa; Lenguerrand, Erik; Maynard, Maria; Teyhan, Alison; Cruickshank, J Kennedy; Der, Geoff

2010-04-01

The cause of ethnic differences in cardiovascular disease remains a scientific challenge. Blood pressure tracks from late childhood to adulthood. We examined ethnic differences in changes in blood pressure between early and late adolescence in the United Kingdom. Longitudinal measures of blood pressure, height, weight, leg length, smoking, and socioeconomic circumstances were obtained from London, United Kingdom, schoolchildren of White British (n=692), Black Caribbean (n=670), Black African (n=772), Indian (n=384), and Pakistani and Bangladeshi (n=402) ethnicity at 11 to 13 years and 14 to 16 years. Predicted age- and ethnic-specific means of blood pressure, adjusted for anthropometry and social exposures, were derived using mixed models. Among boys, systolic blood pressure did not differ by ethnicity at 12 years, but the greater increase among Black Africans than Whites led to higher systolic blood pressure at 16 years (+2.9 mm Hg). Among girls, ethnic differences in mean systolic blood pressure were not significant at any age, but while systolic blood pressure hardly changed with age among White girls, it increased among Black Caribbeans and Black Africans. Ethnic differences in diastolic blood pressure were more marked than those for systolic blood pressure. Body mass index, height, and leg length were independent predictors of blood pressure, with few ethnic-specific effects. Socioeconomic disadvantage had a disproportionate effect on blood pressure for girls in minority groups. The findings suggest that ethnic divergences in blood pressure begin in adolescence and are particularly striking for boys. They signal the need for early prevention of adverse cardiovascular disease risks in later life.