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Sample records for double effect vapour

  1. Microwave-assisted double insert vapour-phase digestion of organic samples.

    PubMed

    Eilola, Keijo; Perämäki, Paavo

    2009-02-23

    A microwave-assisted double insert multimode vapour-phase digestion method was developed for the digestion of organic samples. The experimental set-up was based on a third generation-type teflon microwave vessel, equipped with an automatic pressure regulating type vessel cover. A borosilicate glass holder insert, containing a smaller quartz sample insert, was fitted inside the vessel. Sulphuric acid was added to the holder insert as a microwave absorbing and temperature transferring liquid, which transferred heat to the sample insert (into which the sample was weighed) and charred the sample material. Oxidation of the sample material was carried out simultaneously with charring using nitric acid vapour, which was generated by the 1:1 (v/v) sulphuric acid-nitric acid mixture located in the bottom of the microwave vessel. This set-up generated high digestion efficiency, without any of the interferences normally associated with direct sulphuric acid usage. The method was used for determining the concentrations of Cd, Cr, Cu, Mn, Mo, Zn and Fe in certified organic reference materials using ICP-OES instrumentation. The certified organic reference materials were NRCC DOLT-2 dogfish liver, NIST-SRM 1577b bovine liver and IRMM VDA cadmium in polyethylene No. 001 and No. 004. The results were in good agreement with the certified values, forepart from Cd. For Cd the results were lower than the certified values due to volatilization losses. Sample materials that could not be digested by an earlier procedure were completely digested during a single-step, 30 min digestion. The tested sample materials included certified reference materials, 3-nitrobenzoic acid (3-NBA) and pike (Esox lucius) muscle. The residual carbon concentrations in the digestion solutions were below the detection limit of the TOC instrument. This type of digestion method is described here for the first time in the literature. PMID:19185121

  2. Residual neurobehavioural effects associated with chronic exposure to mercury vapour.

    PubMed Central

    Kishi, R; Doi, R; Fukuchi, Y; Satoh, H; Satoh, T; Ono, A; Moriwaka, F; Tashiro, K; Takahata, N; Sasatani, H

    1994-01-01

    To find the residual effects of long term exposure to mercury vapour, neurobehavioural tests were given to ex-mercury miners about 18 years after the end of mercury exposure. Seventy six male ex-mercury miners who had been exposed to high concentrations of mercury vapour (over 1.0 mg/m3) and with a history of mercury intoxication were compared with controls matched for age (within 3 years), sex, and education. Although the extent of the workers' symptoms caused by mercury poisoning, termed erethismus merculialis, decreased considerably after the end of exposure, matched paired comparison showed that performances of motor coordination, simple reaction time, and short term memory had deteriorated significantly in the exposed group. Multiple linear regression analysis of exposure variables with neurological examination measures showed positive correlations between poorer neurological performance and variables related to mercury exposure. Thus the duration of exposure correlated with poorer performance of hand-eye coordination, tapping, and a colour card reading test. Job categories classified by exposure to mercury also had a significant negative correlation with these performances. The period of years after the end of exposure had a significant correlation with better performance of reaction time and digit span. On the other hand, the history of intoxication itself had no significant correlation with any of the current neurobehavioural performances. These results suggest that there are slight but persistent effects on neurobehavioural function, especially on motor coordination, among mercury miners even more than 10 years after the end of exposure. PMID:8124461

  3. 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.

  4. 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. PMID:27392307

  5. Pressure effects on water vapour lines: beyond the Voigt profile.

    PubMed

    Ngo, N H; Tran, H; Gamache, R R; Hartmann, J M

    2012-06-13

    A short overview of recent results on the effects of pressure (collisions) regarding the shape of isolated infrared lines of water vapour is presented. The first part of this study considers the basic collisional quantities, which are the pressure-broadening and -shifting coefficients, central parameters of the Lorentzian (and Voigt) profile and thus of any sophisticated line-shape model. Through comparisons of measured values with semi-classical calculations, the influences of the molecular states (both rotational and vibrational) involved and of the temperature are analysed. This shows the relatively unusual behaviour of H(2)O broadening, with evidence of a significant vibrational dependence and the fact that the broadening coefficient (in cm(-1) atm(-1)) of some lines increases with temperature. In the second part of this study, line shapes beyond the Voigt model are considered, thus now taking 'velocity effects' into account. These include both the influence of collisionally induced velocity changes that lead to the so-called Dicke narrowing and the influence of the dependence of collisional parameters on the speed of the radiating molecule. Experimental evidence of deviations from the Voigt shape is presented and analysed. The interest of classical molecular dynamics simulations, to model velocity changes, together with semi-classical calculations of the speed-dependent collisional parameters for line-shape predictions from 'first principles', are discussed. PMID:22547229

  6. 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. PMID:26141510

  7. 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

  8. 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

  9. 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. PMID:25432426

  10. Assessment of chronic neuropsychological effects of mercury vapour poisoning in chloral-alkali plant workers.

    PubMed

    Pranjić, Nurka; Sinanović, Osman; Karamehić, Jasenko; Jakubović, Rusid

    2002-12-01

    A prospective case study was conducted in the Department of Occupational Medicine, Tuzla. The purpose of this study was to indicate negative effects from occupational exposure to mercury on behavioural and mental health, memory and psychomotor function that was tested in 46 chloral-alkali plant workers (mean age was 38. 8+/- 5. 7 years; mean age of occupational history 16. 5+/- 6. 0 years). Data on toxicological monitoring on atomic absorption spectrometer, and data on mental health were collected, psychiatric and other subjective symptoms, and behavioural, psychomotor and memory function tested. The data were compared to control group, 32 healthy non exposed workers. The study was designed to assess blood and urine mercury levels and length of occupational exposure and investigate its relationships to effects on the mental health. The mean air mercury levels were 0.23 mg/m3, the mean blood mercury concentrations was 3. 6 mg/ dl and the mean urine mercury concentrations were 151.7 +/- 180.4 mg/l. In 25 (53%) workers exposed to mercury vapour was identified Depression-Hypochondrias Syndrome (p trend < 0. 001) with higher scores for scales: Hysteria (p trend <0. 001), Schizoid and Psychoastenia (MMPI). All psychological parameters were in highly significantly correlations with mercury levels and length of occupational exposure. Pathological parameters were possible general identified if the concentration of blood mercury levels are >2. 9 mg/ dl, or urine mercury levels > 87 mg/l workers exposed to mercury vapour knew that toxic effects in body resulted in loosing some of intellectual abilities, and that people who handle chemicals had an increased health risk (ESW questionnaire). The occupational mercury exposed workers had introvert behaviour (EPQ). Aggressiveness was found in 71.7% workers. The cognitive disturbances: short-term memory loss, difficult to concentrate on tasks which require attention and thinking, were significantly differed compared to those of

  11. THE EFFECT OF ODOURS, IRRITANT VAPOURS, AND MENTAL WORK UPON THE BLOOD FLOW

    PubMed Central

    Shields, T. E.

    1896-01-01

    The most important of this investigation has been the completion of various improvements in the construction and use of the plethysmograph, by means of which numerous errors attending the use of the instrument have been eliminated. The results of the work show that all olfactory sensations, so far as they produce any effect through the vasomotor system, tend to diminish the volume of the arm, and therefore presumably cause a congestion of the brain. Whenever the stimulation occassions an increase in the volume of the arm, as sometimes happens, it seems to be due to acceleration of the heart rate, which, of course, tends also to increase the supply of blood to the brain. The of odours varies in extent with different individuals, and with the same individual at different times. It was most marked in subjects sensitive to odours. Irritant vapours, such as formic acid, have a marked effect in the same direction—that is, they cause a strong diminution in the volume of the arm. The experiments give no support to the view that pleasant sensations are accompanied by a diminution of the See PDF for Structure blood supply to the brain and unpleasant sensations by the reverse efeect. In all my experiments mental work caused a marked and prolonged diminution in the volume of the arm. This vasomotor effect was sometimes preceded by a transitory increase in the volume of the arm caused by acceleration of heart rate. PMID:19866796

  12. Who is entitled to double effect?

    PubMed

    Boyle, J

    1991-10-01

    The doctrine of double effect continues to be an important tool in bioethical casuistry. Its role within the Catholic moral tradition continues, and there is considerable interest in it by contemporary moral philosophers. But problems of justification and correct application remain. I argue that if the traditional Catholic conviction that there are exceptionless norms prohibiting inflicting some kinds of harms on people is correct, then double effect is justified and necessary. The objection that double effect is superfluous is a rejection of that normative conviction, not a refutation of double effect itself. This justification suggests the correct way of applying double effect to controversial cases. But versions of double effect which dispense with the absolutism of the Catholic tradition lack justification and fall to the objection that double effect is an unnecessary complication.

  13. Who is entitled to double effect?

    PubMed

    Boyle, J

    1991-10-01

    The doctrine of double effect continues to be an important tool in bioethical casuistry. Its role within the Catholic moral tradition continues, and there is considerable interest in it by contemporary moral philosophers. But problems of justification and correct application remain. I argue that if the traditional Catholic conviction that there are exceptionless norms prohibiting inflicting some kinds of harms on people is correct, then double effect is justified and necessary. The objection that double effect is superfluous is a rejection of that normative conviction, not a refutation of double effect itself. This justification suggests the correct way of applying double effect to controversial cases. But versions of double effect which dispense with the absolutism of the Catholic tradition lack justification and fall to the objection that double effect is an unnecessary complication. PMID:1779208

  14. Effects of ultraviolet irradiation, pulsed electric field, hot water and ethanol vapours treatment on functional properties of mung bean sprouts.

    PubMed

    Goyal, Ankit; Siddiqui, Saleem; Upadhyay, Neelam; Soni, Jyoti

    2014-04-01

    The present investigation was conducted with the objective to study the effects of various treatments and storage conditions on ascorbic acid, total phenols, antioxidant activity and polyphenol oxidase activity of mung bean sprouts. The sprouts subjected to various treatments viz., pulsed electric field (PEF) (10,000 V for 10 s), hot water dip (HWD) (50 °C for 2 min), ethanol vapours (1 h) and UV-Irradiation (10 kJm(-2) in laminar flow chamber for 1 h); and then stored at room (25 ± 1 °C) and low (7 ± 1 °C) temperature conditions. The sprouts were analyzed regularly at 24 h interval till end of shelf life. Different treatments given to sprouts resulted in differential effect on various parameters. The ascorbic acid, total phenols and antioxidant activity were highest in ethanol vapours treated sprouts. There was a general decrease in polyphenol oxidase activity by various treatments. During storage ascorbic acid, total phenols and antioxidant activity of sprouts first increased and then decreased significantly, however, for polyphenol oxidase activity a progressive increase with increase in storage period was observed. The trends were similar at room and low temperature storage conditions. Thus, it can be concluded that the ethanol vapours significantly improved the ascorbic acid content, total phenols and antioxidant activity of mung bean sprouts, both at room as well as low temperature conditions of storage. PMID:24741164

  15. Detection of water vapour absorption around 363nm in measured atmospheric absorption spectra and its effect on DOAS evaluations

    NASA Astrophysics Data System (ADS)

    Lampel, Johannes; Polyansky, Oleg. L.; Kyuberis, Alexandra A.; Zobov, Nikolai F.; Tennyson, Jonathan; Lodi, Lorenzo; Pöhler, Denis; Frieß, Udo; Platt, Ulrich; Beirle, Steffen; Wagner, Thomas

    2016-04-01

    Water vapour is known to absorb light from the microwave region to the blue part of the visible spectrum at a decreasing magnitude. Ab-initio approaches to model individual absorption lines of the gaseous water molecule predict absorption lines until its dissociation limit at 243 nm. We present first evidence of water vapour absorption at 363 nm from field measurements based on the POKAZATEL absorption line list by Polyansky et al. (2016) using data from Multi-Axis differential optical absorption spectroscopy (MAX-DOAS) and Longpath (LP)-DOAS measurements. The predicted absorptions contribute significantly to the observed optical depths with up to 2 × 10‑3. Their magnitude correlates well (R2 = 0.89) to simultaneously measured well-established water vapour absorptions in the blue spectral range from 452-499 nm, but is underestimated by a factor of 2.6 ± 0.6 in the ab-initio model. At a spectral resolution of 0.5nm this leads to a maximum absorption cross-section value of 5.4 × 10‑27 cm2/molec at 362.3nm. The results are independent of the employed cross-section data to compensate for the overlayed absorption of the oxygen dimer O4. The newly found absorption can have a significant impact on the spectral retrieval of absorbing trace-gas species in the spectral range around 363 nm. Its effect on the spectral analysis of O4, HONO and OClO are discussed.

  16. Isothermal vapour flow in extremely dry soils

    NASA Astrophysics Data System (ADS)

    Todman, L. C.; Ireson, A. M.; Butler, A. P.; Templeton, M. R.

    2012-04-01

    In dry soils hydraulic connectivity within the liquid water phase decreases and vapour flow becomes a significant transport mechanism for water. The temperature or solute concentration of the liquid phase affects the vapour pressure of the surrounding air, thus temperature or solute gradients can drive vapour flows. However, in extremely dry soils where water is retained by adsorptive forces rather than capillarity, vapour flows can also occur. In such soils tiny changes in water content significantly affect the equilibrium vapour pressure in the soil, and hence small differences in water content can initiate vapour pressure gradients. In many field conditions this effect may be negligible compared to vapour flows driven by other factors. However, flows of this type are particularly significant in a new type of subsurface irrigation system which uses pervaporation, via a polymer tubing, as the mechanism for water supply. In this system, water enters the soil in vapour phase. Experiments were performed in laboratory conditions using marine sand that had previously been oven dried and cooled. This dry sand was used to represent the desert conditions in which this irrigation system is intended for use. Experimental results show that isothermal vapour flows can significantly affect the performance of such irrigation systems due to the rapid transport of water through the soil via the vapour phase. When the irrigation pipe was buried at a depth of 10cm a vapour flow from the soil surface was observed in less than 2 hours. These flows therefore affect the loss of mass into the atmosphere and thus must be considered when evaluating the availability of water for the irrigated crop. The experiments also provide a rare opportunity to observe isothermal vapour flows initiating from a subsurface source. Such experiments allow the significance of these flows to be quantified and potentially applied to other areas of arid zone hydrology.

  17. Effect of temperature and relative humidity on the water vapour permeability and mechanical properties of cassava starch and soy protein concentrate based edible films.

    PubMed

    Chinma, C E; Ariahu, C C; Alakali, J S

    2015-04-01

    The effect of temperature and relative humidity on the water vapour permeability (WVP) and mechanical properties of cassava starch and soy protein concentrate (SPC) based edible films containing 20 % glycerol level were studied. Tensile strength and elastic modulus of edible films increased with increase in temperature and decreased with increase in relative humidity, while elongation at break decreased. Water vapour permeability of the films increased (2.6-4.3 g.mm/m(2).day.kPa) with increase in temperature and relative humidity. The temperature dependence of water vapour permeation of cassava starch-soy protein concentrate films followed Arrhenius relationship. Activation energy (Ea) of water vapour permeation of cassava starch-soy protein concentrate edible films ranged from 1.9 to 5.3 kJ/mol (R (2)  ≥ 0.93) and increased with increase in SPC addition. The Ea values were lower for the bio-films than for polyvinylidene chloride, polypropylene and polyethylene which are an indication of low water vapour permeability of the developed biofilms compared to those synthetic films.

  18. Naphthalene contamination of sterilized milk drinks contained in low-density polyethylene bottles. Part 2. Effect of naphthalene vapour in air.

    PubMed

    Lau, O W; Wong, S K; Leung, K S

    1995-04-01

    A survey on naphthalene vapour in air was conducted, revealing that the ambient atmosphere contained concentrations of naphthalene in the range of 0.005-0.100 mg m-3. The level of naphthalene vapour in air increased to 0.35 and 4.00 mg m-3 in places exposed to lacquer paint and naphthalene-based moth-repellent, respectively. The effect of naphthalene vapour in air on milk drinks contained in low-density polyethylene (LDPE) bottles was assessed. A mathematical model was suggested to describe the migration of naphthalene from the atmosphere into milk. The model was proved to be valid for milk drinks exposed to naphthalene-based moth-repellent during storage. Moreover, the extent of migration was found to increase with the fat content of foods, which might be ascribed to an increase in diffusion, in addition to the kinetic factor, that affects naphthalene migration.

  19. Effect of catalyst diameter on vapour-liquid-solid growth of GaAs nanowires

    SciTech Connect

    O'Dowd, B. J. Shvets, I. V.; Wojtowicz, T.; Kolkovsky, V.; Wojciechowski, T.; Zgirski, M.; Rouvimov, S.; Liu, X.; Pimpinella, R.; Dobrowolska, M.; Furdyna, J.

    2014-08-14

    GaAs nanowires were grown on (111)B GaAs substrates using the vapour-liquid-solid mechanism. The Au/Pt nanodots used to catalyse wire growth were defined lithographically and had varying diameter and separation. An in-depth statistical analysis of the resulting nanowires, which had a cone-like shape, was carried out. This revealed that there were two categories of nanowire present, with differing height and tapering angle. The bimodal nature of wire shape was found to depend critically on the diameter of the Au-Ga droplet atop the nanowire. Transmission electron microscopy analysis also revealed that the density of stacking faults in the wires varied considerably between the two categories of wire. It is believed that the cause of the distinction in terms of shape and crystal structure is related to the contact angle between the droplet and the solid-liquid interface. The dependency of droplet diameter on contact angle is likely related to line-tension, which is a correction to Young's equation for the contact angle of a droplet upon a surface. The fact that contact angle may influence resulting wire structure and shape has important implications for the planning of growth conditions and the preparation of wires for use in proposed devices.

  20. Modelling the Effect of Fruit Growth on Surface Conductance to Water Vapour Diffusion

    PubMed Central

    GIBERT, CAROLINE; LESCOURRET, FRANÇOISE; GÉNARD, MICHEL; VERCAMBRE, GILLES; PÉREZ PASTOR, ALEJANDRO

    2005-01-01

    • Background and Aims A model of fruit surface conductance to water vapour diffusion driven by fruit growth is proposed. It computes the total fruit conductance by integrating each of its components: stomata, cuticle and cracks. • Methods The stomatal conductance is computed from the stomatal density per fruit and the specific stomatal conductance. The cuticular component is equal to the proportion of cuticle per fruit multiplied by its specific conductance. Cracks are assumed to be generated when pulp expansion rate exceeds cuticle expansion rate. A constant percentage of cracks is assumed to heal each day. The proportion of cracks to total fruit surface area multiplied by the specific crack conductance accounts for the crack component. The model was applied to peach fruit (Prunus persica) and its parameters were estimated from field experiments with various crop load and irrigation regimes. • Key Results The predictions were in good agreement with the experimental measurements and for the different conditions (irrigation and crop load). Total fruit surface conductance decreased during early growth as stomatal density, and hence the contribution of the stomatal conductance, decreased from 80 to 20 % with fruit expansion. Cracks were generated for fruits exhibiting high growth rates during late growth and the crack component could account for up to 60 % of the total conductance during the rapid fruit growth. The cuticular contribution was slightly variable (around 20 %). Sensitivity analysis revealed that simulated conductance was highly affected by stomatal parameters during the early period of growth and by both crack and stomatal parameters during the late period. Large fruit growth rate leads to earlier and greater increase of conductance due to higher crack occurrence. Conversely, low fruit growth rate accounts for a delayed and lower increase of conductance. • Conclusions By predicting crack occurrence during fruit growth, this model could be helpful

  1. High performance vapour-cell frequency standards

    NASA Astrophysics Data System (ADS)

    Gharavipour, M.; Affolderbach, C.; Kang, S.; Bandi, T.; Gruet, F.; Pellaton, M.; Mileti, G.

    2016-06-01

    We report our investigations on a compact high-performance rubidium (Rb) vapour-cell clock based on microwave-optical double-resonance (DR). These studies are done in both DR continuous-wave (CW) and Ramsey schemes using the same Physics Package (PP), with the same Rb vapour cell and a magnetron-type cavity with only 45 cm3 external volume. In the CW-DR scheme, we demonstrate a DR signal with a contrast of 26% and a linewidth of 334 Hz; in Ramsey-DR mode Ramsey signals with higher contrast up to 35% and a linewidth of 160 Hz have been demonstrated. Short-term stabilities of 1.4×10-13 τ-1/2 and 2.4×10-13 τ-1/2 are measured for CW-DR and Ramsey-DR schemes, respectively. In the Ramsey-DR operation, thanks to the separation of light and microwave interactions in time, the light-shift effect has been suppressed which allows improving the long-term clock stability as compared to CW-DR operation. Implementations in miniature atomic clocks are considered.

  2. Mercury vapour suppression by various liquid media.

    PubMed

    Sutow, E J; Foong, W C; Rizkalla, A S; Jones, D W; Power, N L

    1994-09-01

    Fresh and used photographic fixer, Merconvap and water were evaluated for their ability to suppress the vapourization of mercury. Mercury vapour concentration above the four test storage liquids was measured at various times between 10 min and 335 days, using a mercury vapour measuring instrument. The data were analysed using a Student-Newman-Keuls multiple comparison test (P = 0.05). The results showed that fresh and used fixer and Merconvap suppressed the vapourization of mercury to below the detection limit of the measuring instrument (0.01 mg/m3). Water was much less effective compared with the other liquids and showed an increase in mercury vapour concentration with log t. PMID:7996339

  3. Effects of different doses of gamma irradiation on oxygen and water vapour transmission rate of preserved human amniotic membrane.

    PubMed

    Zahari, Nor Kamalia; Sheikh Ab Hamid, Suzina; Yusof, Norimah

    2015-03-01

    Preserved human amniotic membrane either air dried or glycerol preserved has been used effectively to treat superficial and partial thickness wounds without leaving any obvious hypertrophic scar. The preserved amnion, sterilised by ionising radiation, is known as an effective barrier for heat, fluid and protein loss while adheres nicely on wound. Air drying slightly reduced the oxygen transmission rate (OTR) of the amnion and the value significantly dropped after 15 kGy (p < 0.05). Glycerol preservation significantly reduced (p < 0.05) the OTR indicating less oxygen transmitted through the well structured cells of the amnion. Increase in the OTR with the increasing radiation doses up to 35 kGy possibly due to direct effects of radiation that resulted in large intercellular gaps. Both preservation methods significantly increased (p < 0.05) the water vapour transmission rate (WVTR). However, the low WVTR in the air dried amnion at 15 and 25 kGy was postulated due to cross-linking of collagen. Changes in the biophysical properties can be linked to direct and indirect effects of radiation on collagen bundles. The radiation dose of 25 kGy caused no adverse effect on biophysical properties hence it is still acceptable to sterilize both the air dried and the glycerol preserved amnions.

  4. Double meanings will not save the principle of double effect.

    PubMed

    Douglas, Charles D; Kerridge, Ian H; Ankeny, Rachel A

    2014-06-01

    In an article somewhat ironically entitled "Disambiguating Clinical Intentions," Lynn Jansen promotes an idea that should be bewildering to anyone familiar with the literature on the intention/foresight distinction. According to Jansen, "intention" has two commonsense meanings, one of which is equivalent to "foresight." Consequently, questions about intention are "infected" with ambiguity-people cannot tell what they mean and do not know how to answer them. This hypothesis is unsupported by evidence, but Jansen states it as if it were accepted fact. In this reply, we make explicit the multiple misrepresentations she has employed to make her hypothesis seem plausible. We also point out the ways in which it defies common sense. In particular, Jansen applies her thesis only to recent empirical research on the intentions of doctors, totally ignoring the widespread confusion that her assertion would imply in everyday life, in law, and indeed in religious and philosophical writings concerning the intention/foresight distinction and the Principle of Double Effect.

  5. Double meanings will not save the principle of double effect.

    PubMed

    Douglas, Charles D; Kerridge, Ian H; Ankeny, Rachel A

    2014-06-01

    In an article somewhat ironically entitled "Disambiguating Clinical Intentions," Lynn Jansen promotes an idea that should be bewildering to anyone familiar with the literature on the intention/foresight distinction. According to Jansen, "intention" has two commonsense meanings, one of which is equivalent to "foresight." Consequently, questions about intention are "infected" with ambiguity-people cannot tell what they mean and do not know how to answer them. This hypothesis is unsupported by evidence, but Jansen states it as if it were accepted fact. In this reply, we make explicit the multiple misrepresentations she has employed to make her hypothesis seem plausible. We also point out the ways in which it defies common sense. In particular, Jansen applies her thesis only to recent empirical research on the intentions of doctors, totally ignoring the widespread confusion that her assertion would imply in everyday life, in law, and indeed in religious and philosophical writings concerning the intention/foresight distinction and the Principle of Double Effect. PMID:24737837

  6. The Effects of Exposure to Petrol Vapours on Growth, Haematological Parameters and Oxidative Markers in Sprague-Dawley Male Rats

    PubMed Central

    ABUBAKAR, Murtala Bello; ABDULLAH, Wan Zaidah; SULAIMAN, Siti Amrah; ANG, Boon Suen

    2015-01-01

    Background: Petrol is known to be hazardous to human health and is associated with various health effects, such as haematotoxicity and oxidative stress. Although Malaysia has adopted the European fuel quality standards in recent years in order to reduce petroleum pollutants and to improve air quality, gasoline with research octane number 95 (RON95), believed to contain benzene and other toxic substances, is still widely used all over the country. This study assessed the effect of RON95 gasoline on haemtological parameters of rats after 11 weeks of exposure. Methods: A total of 16 male Sprague-Dawley rats were randomly divided into two groups: control (exposed to ambient air daily) and gasoline exposed (exposed to petrol fumes at 11.13 ± 1.1cm3/h for 6h daily, 6 days/week) groups. Body weight was monitored daily. At the end of 11 weeks, the rats were sacrificed, bone marrow was extracted for cytological examination, and blood samples were collected for a full blood picture examination, full blood counts and oxidative markers. Results: The results show that gasoline inhalation was associated with a significant (P < 0.05) reduction in the rate of weight gain and a reduction in mean corpuscular haemoglobin concentration and red cell distribution width. It was also observed that the inhalation of gasoline was associated with changes in the nuclei of megakaryocytes, hence causing an increase in the percentage of abnormal megakaryocytes with detached nuclei, hypo-lobulation and/or disintegration. However, the inhalation of gasoline did not cause significant changes in oxidative markers in the erythrocytes. Conclusion: This study shows that 11 weeks of inhaling RON95 petrol vapours caused adverse effects on weight gain, blood cell indices and bone marrow megakaryocytes, but did not cause significant changes in oxidative markers in erythrocytes. The definitive effects of these changes on health require further confirmation. PMID:25892947

  7. Predicting equilibrium vapour pressure isotope effects by using artificial neural networks or multi-linear regression - A quantitative structure property relationship approach.

    PubMed

    Parinet, Julien; Julien, Maxime; Nun, Pierrick; Robins, Richard J; Remaud, Gerald; Höhener, Patrick

    2015-09-01

    We aim at predicting the effect of structure and isotopic substitutions on the equilibrium vapour pressure isotope effect of various organic compounds (alcohols, acids, alkanes, alkenes and aromatics) at intermediate temperatures. We attempt to explore quantitative structure property relationships by using artificial neural networks (ANN); the multi-layer perceptron (MLP) and compare the performances of it with multi-linear regression (MLR). These approaches are based on the relationship between the molecular structure (organic chain, polar functions, type of functions, type of isotope involved) of the organic compounds, and their equilibrium vapour pressure. A data set of 130 equilibrium vapour pressure isotope effects was used: 112 were used in the training set and the remaining 18 were used for the test/validation dataset. Two sets of descriptors were tested, a set with all the descriptors: number of(12)C, (13)C, (16)O, (18)O, (1)H, (2)H, OH functions, OD functions, CO functions, Connolly Solvent Accessible Surface Area (CSA) and temperature and a reduced set of descriptors. The dependent variable (the output) is the natural logarithm of the ratios of vapour pressures (ln R), expressed as light/heavy as in classical literature. Since the database is rather small, the leave-one-out procedure was used to validate both models. Considering higher determination coefficients and lower error values, it is concluded that the multi-layer perceptron provided better results compared to multi-linear regression. The stepwise regression procedure is a useful tool to reduce the number of descriptors. To our knowledge, a Quantitative Structure Property Relationship (QSPR) approach for isotopic studies is novel.

  8. Predicting equilibrium vapour pressure isotope effects by using artificial neural networks or multi-linear regression - A quantitative structure property relationship approach.

    PubMed

    Parinet, Julien; Julien, Maxime; Nun, Pierrick; Robins, Richard J; Remaud, Gerald; Höhener, Patrick

    2015-09-01

    We aim at predicting the effect of structure and isotopic substitutions on the equilibrium vapour pressure isotope effect of various organic compounds (alcohols, acids, alkanes, alkenes and aromatics) at intermediate temperatures. We attempt to explore quantitative structure property relationships by using artificial neural networks (ANN); the multi-layer perceptron (MLP) and compare the performances of it with multi-linear regression (MLR). These approaches are based on the relationship between the molecular structure (organic chain, polar functions, type of functions, type of isotope involved) of the organic compounds, and their equilibrium vapour pressure. A data set of 130 equilibrium vapour pressure isotope effects was used: 112 were used in the training set and the remaining 18 were used for the test/validation dataset. Two sets of descriptors were tested, a set with all the descriptors: number of(12)C, (13)C, (16)O, (18)O, (1)H, (2)H, OH functions, OD functions, CO functions, Connolly Solvent Accessible Surface Area (CSA) and temperature and a reduced set of descriptors. The dependent variable (the output) is the natural logarithm of the ratios of vapour pressures (ln R), expressed as light/heavy as in classical literature. Since the database is rather small, the leave-one-out procedure was used to validate both models. Considering higher determination coefficients and lower error values, it is concluded that the multi-layer perceptron provided better results compared to multi-linear regression. The stepwise regression procedure is a useful tool to reduce the number of descriptors. To our knowledge, a Quantitative Structure Property Relationship (QSPR) approach for isotopic studies is novel. PMID:25559176

  9. Chronic effects of vapour phase di-n-butyl phthalate (DBP) on six plant species.

    PubMed

    Dueck, Th A; Van Dijk, C J; David, F; Scholz, N; Vanwalleghem, F

    2003-12-01

    A fumigation experiment was performed in which six plant species representing the European flora were exposed to a range of DBP concentrations. Controlled amounts of DBP-saturated air were injected into the ingoing air-streams of plant fumigation chambers, maintaining constant concentrations there for a period of up to 76 days. The target concentrations were a control, 0.8, 1.5, 3.5, and 10.0 microg m(-3). The variation in sensitivity between plant species to atmospheric DBP was quantified on the basis of whole plant biomass in order to derive no-observed-effect-concentrations (NOECs). Significant dose-response relationships, based on realised concentrations, were thus derived using non-linear regression, resulting in NOECs of 0.51 microg m(-3) for Trifolium repens, 0.96 microg m(-3) for Brassica campestris, 1.87 microg m(-3) for Phaseolus vulgaris and 2.21 microg m(-3) for Plantago major. A significant effect was also observed for Holcus lanatus at 12.4 microg m(-3) DBP, but due to the variation at lower levels of DBP exposure, no dose-response relationship could be derived. No significant effect on growth of current year needles in Picea abies was observed, even at the highest level of DBP, 13.7 microg m(-3). Based on statistical extrapolation according to Aldenberg and Slob [Ecotox. Environ. Safety, 25 (1993) 48], an overall predicted no-effect concentration (PNEC) for the plant-atmosphere compartment of 0.33 microg m(-3) DBP was calculated. The PNEC was calculated using the mean and standard deviation of the NOEC for four of the tested species and an extrapolation factor. In addition to changes in leaf colour, leaf crinkling and growth reduction, a number of not quantified observations are described, indicating that DBP affects the physiology as well as the morphology of these species. PMID:14505713

  10. Effects of occupational exposure to mercury vapour on the central nervous system.

    PubMed Central

    Langworth, S; Almkvist, O; Söderman, E; Wikström, B O

    1992-01-01

    Possible effects of mercury on the central nervous system (CNS) were examined in a group of chloralkali workers exposed to mercury (n = 89) and compared with a control group (n = 75), by registration of subjective symptoms, personality changes, forearm tremor, and performance on six computerised psychometric tests in the two groups. The groups were similar in age, education, verbal comprehension, and work tasks. In the chloralkali group, median blood mercury concentration (B-Hg) was 55 nmol/l, serum mercury concentration (S-Hg) 45 nmol/l, and urine mercury concentration (U-Hg) 14.3 nmol/mmol creatinine (25.4 micrograms/g creatinine). Corresponding concentrations in the control group were 15 nmol/l, 4 nmol/l, and 1.1 nmol/mmol creatinine (1.9 micrograms/g creatinine) respectively. The number of self reported symptoms, the scores for tiredness and confusion in the profile of mood states (POMS), and the degree of neuroticism in the Eysenck personality inventory (EPI), were significantly higher in the mercury exposed group compared with the controls. Performance on the psychometric tests and tremor frequency spectra did not differ significantly between the two groups. Dose-response calculations showed weak but statistically significant relations between symptom prevalence and current mercury concentrations in both blood and urine. The performance on three of the psychometric tests was negatively correlated with earlier peak exposures. The findings indicate a slight mercury induced effect on the CNS among the chloralkali workers. PMID:1515346

  11. The Effect of Climate Change on Ozone Depletion through Changes in Stratospheric Water Vapour

    NASA Technical Reports Server (NTRS)

    Kirk-Davidoff, Daniel B.; Hintsa, Eric J.; Anderson, James G.; Keith, David W.

    1999-01-01

    Several studies have predicted substantial increases in Arctic ozone depletion due to the stratospheric cooling induced by increasing atmospheric CO2 concentrations. But climate change may additionally influence Arctic ozone depletion through changes in the water vapor cycle. Here we investigate this possibility by combining predictions of tropical tropopause temperatures from a general circulation model with results from a one-dimensional radiative convective model, recent progress in understanding the stratospheric water vapor budget, modelling of heterogeneous reaction rates and the results of a general circulation model on the radiative effect of increased water vapor. Whereas most of the stratosphere will cool as greenhouse-gas concentrations increase, the tropical tropopause may become warmer, resulting in an increase of the mean saturation mixing ratio of water vapor and hence an increased transport of water vapor from the troposphere to the stratosphere. Stratospheric water vapor concentration in the polar regions determines both the critical temperature below which heterogeneous reactions on cold aerosols become important (the mechanism driving enhanced ozone depletion) and the temperature of the Arctic vortex itself. Our results indicate that ozone loss in the later winter and spring Arctic vortex depends critically on water vapor variations which are forced by sea surface temperature changes in the tropics. This potentially important effect has not been taken into account in previous scenarios of Arctic ozone loss under climate change conditions.

  12. Effect of dispersive long-range corrections to the pressure tensor: The vapour-liquid interfacial properties of the Lennard-Jones system revisited

    SciTech Connect

    Martínez-Ruiz, F. J.; Blas, F. J.; Mendiboure, B.; Moreno-Ventas Bravo, A. I.

    2014-11-14

    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, 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 interfacial

  13. Effect of dispersive long-range corrections to the pressure tensor: the vapour-liquid interfacial properties of the Lennard-Jones system revisited.

    PubMed

    Martínez-Ruiz, F J; Blas, F J; Mendiboure, B; Moreno-Ventas Bravo, A I

    2014-11-14

    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(c) = 2.5, 3, 4, and 5σ. In addition, we have also considered cutoff distances r(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 interfacial thickness

  14. Piezoelectric effect in chemical vapour deposition-grown atomic-monolayer triangular molybdenum disulfide piezotronics.

    PubMed

    Qi, Junjie; Lan, Yann-Wen; Stieg, Adam Z; Chen, Jyun-Hong; Zhong, Yuan-Liang; Li, Lain-Jong; Chen, Chii-Dong; Zhang, Yue; Wang, Kang L

    2015-01-01

    High-performance piezoelectricity in monolayer semiconducting transition metal dichalcogenides is highly desirable for the development of nanosensors, piezotronics and photo-piezotransistors. Here we report the experimental study of the theoretically predicted piezoelectric effect in triangle monolayer MoS2 devices under isotropic mechanical deformation. The experimental observation indicates that the conductivity of MoS2 devices can be actively modulated by the piezoelectric charge polarization-induced built-in electric field under strain variation. These polarization charges alter the Schottky barrier height on both contacts, resulting in a barrier height increase with increasing compressive strain and decrease with increasing tensile strain. The underlying mechanism of strain-induced in-plane charge polarization is proposed and discussed using energy band diagrams. In addition, a new type of MoS2 strain/force sensor built using a monolayer MoS2 triangle is also demonstrated. Our results provide evidence for strain-gating monolayer MoS2 piezotronics, a promising avenue for achieving augmented functionalities in next-generation electronic and mechanical-electronic nanodevices. PMID:26109177

  15. Piezoelectric effect in chemical vapour deposition-grown atomic-monolayer triangular molybdenum disulfide piezotronics

    PubMed Central

    Qi, Junjie; Lan, Yann-Wen; Stieg, Adam Z.; Chen, Jyun-Hong; Zhong, Yuan-Liang; Li, Lain-Jong; Chen, Chii-Dong; Zhang, Yue; Wang, Kang L.

    2015-01-01

    High-performance piezoelectricity in monolayer semiconducting transition metal dichalcogenides is highly desirable for the development of nanosensors, piezotronics and photo-piezotransistors. Here we report the experimental study of the theoretically predicted piezoelectric effect in triangle monolayer MoS2 devices under isotropic mechanical deformation. The experimental observation indicates that the conductivity of MoS2 devices can be actively modulated by the piezoelectric charge polarization-induced built-in electric field under strain variation. These polarization charges alter the Schottky barrier height on both contacts, resulting in a barrier height increase with increasing compressive strain and decrease with increasing tensile strain. The underlying mechanism of strain-induced in-plane charge polarization is proposed and discussed using energy band diagrams. In addition, a new type of MoS2 strain/force sensor built using a monolayer MoS2 triangle is also demonstrated. Our results provide evidence for strain-gating monolayer MoS2 piezotronics, a promising avenue for achieving augmented functionalities in next-generation electronic and mechanical–electronic nanodevices. PMID:26109177

  16. Piezoelectric effect in chemical vapour deposition-grown atomic-monolayer triangular molybdenum disulfide piezotronics.

    PubMed

    Qi, Junjie; Lan, Yann-Wen; Stieg, Adam Z; Chen, Jyun-Hong; Zhong, Yuan-Liang; Li, Lain-Jong; Chen, Chii-Dong; Zhang, Yue; Wang, Kang L

    2015-06-25

    High-performance piezoelectricity in monolayer semiconducting transition metal dichalcogenides is highly desirable for the development of nanosensors, piezotronics and photo-piezotransistors. Here we report the experimental study of the theoretically predicted piezoelectric effect in triangle monolayer MoS2 devices under isotropic mechanical deformation. The experimental observation indicates that the conductivity of MoS2 devices can be actively modulated by the piezoelectric charge polarization-induced built-in electric field under strain variation. These polarization charges alter the Schottky barrier height on both contacts, resulting in a barrier height increase with increasing compressive strain and decrease with increasing tensile strain. The underlying mechanism of strain-induced in-plane charge polarization is proposed and discussed using energy band diagrams. In addition, a new type of MoS2 strain/force sensor built using a monolayer MoS2 triangle is also demonstrated. Our results provide evidence for strain-gating monolayer MoS2 piezotronics, a promising avenue for achieving augmented functionalities in next-generation electronic and mechanical-electronic nanodevices.

  17. An assessment of vapour pressure estimation methods.

    PubMed

    O'Meara, Simon; Booth, Alastair Murray; Barley, Mark Howard; Topping, David; McFiggans, Gordon

    2014-09-28

    Laboratory measurements of vapour pressures for atmospherically relevant compounds were collated and used to assess the accuracy of vapour pressure estimates generated by seven estimation methods and impacts on predicted secondary organic aerosol. Of the vapour pressure estimation methods that were applicable to all the test set compounds, the Lee-Kesler [Reid et al., The Properties of Gases and Liquids, 1987] method showed the lowest mean absolute error and the Nannoolal et al. [Nannoonal et al., Fluid Phase Equilib., 2008, 269, 117-133] method showed the lowest mean bias error (when both used normal boiling points estimated using the Nannoolal et al. [Nannoolal et al., Fluid Phase Equilib., 2004, 226, 45-63] method). The effect of varying vapour pressure estimation methods on secondary organic aerosol (SOA) mass loading and composition was investigated using an absorptive partitioning equilibrium model. The Myrdal and Yalkowsky [Myrdal and Yalkowsky, Ind. Eng. Chem. Res., 1997, 36, 2494-2499] vapour pressure estimation method using the Nannoolal et al. [Nannoolal et al., Fluid Phase Equilib., 2004, 226, 45-63] normal boiling point gave the most accurate estimation of SOA loading despite not being the most accurate for vapour pressures alone. PMID:25105180

  18. Stratospheric water vapour and temperature variability and their effect on polar stratospheric cloud formation and existence in the Arctic

    NASA Astrophysics Data System (ADS)

    Khosrawi, Farahnaz; Urban, Joachim; Lossow, Stefan; Stiller, Gabriele; Weigel, Katja; Braesicke, Peter; Pitts, Michael C.; Murtagh, Donal

    2015-04-01

    Based on more than 10-years of satellite measurements from UARS/HALOE, Envisat/MIPAS, Odin/SMR, Aura/MLS and SciSat/ACE-FTS we investigate water vapour (H2O) variability in the northern hemisphere polar regions. We find from the observations a connection between cold winters and enhanced water vapour mixing ratios in the lower polar stratosphere (475 to 525 K). We perform a sensitivity study along air parcel trajectories to test how an increase of stratospheric water vapour of 1 ppmv or a temperature decrease of 1 K affects the time period during which polar stratospheric clouds (PSCs) can be formed and exist. Air parcel trajectories were calculated 6-days backward in time. The trajectories were started at the time and locations where PSCs were observed by CALIPSO (Cloud Aerosol Lidar and Infrared Pathfinder satellite observations) during the Arctic winter 2010/2011. We test the sensitivity of PSCs formation and existence to changes in H2O and temperature based on PSC observations during this winter since it was one of the coldest Arctic winters in the last decade. The polar vortex persisted over a period of four months, thus leading to extensive PSC formation. During this winter PSCs were detected by CALIPSO on 42 days. In total, 738 trajectories were calculated and analysed. The resulting statistic derived from the air parcel trajectories shows a clear prolongation of the time period where PSCs can be formed and exist when the temperature in the stratosphere is decreased by 1 K and H2O is increased by 1 ppmv. We derive an increase in time where the stratospheric air is exposed to temperatures below Tice and TNAT, respectively, by ~6000 h. Thus, changes in stratospheric water vapour and temperature can prolong PSC formation and existence and thus have a significant influence on the chemistry of the polar stratosphere.

  19. Effects of ultraviolet irradiation, pulsed electric field, hot water dip and ethanol vapours treatment on keeping and sensory quality of mung bean (Vigna radiata L. Wilczek) sprouts.

    PubMed

    Goyal, Ankit; Siddiqui, Saleem

    2014-10-01

    The objective of this research work was to evaluate the effects of UV- irradiation, pulsed electric field (PEF), hot water dip (HWD) and ethanol vapours on the quality and storage life of mung bean sprouts (Vigna radiata L. Wilczek). The sprouts were subjected to various treatments viz., UV-Irradiation (10 kJm(-2) in laminar flow chamber for 1 h), PEF (10,000 V for 10s), HWD (50 °C for 2 min) and ethanol vapours (1 h); and then stored in thermocol cups wrapped with perforated cling films at room (25 ± 1 °C) and low (7 ± 1 °C) temperature conditions. The sprouts were analyzed regularly at 24 h interval for sprout length, sprout weight, total soluble solids (TSS), titratable acidity, non-enzymatic browning, total plate count and overall acceptability. Sprout length and weight increased during storage. There was no significant effect of various treatments on sprout length and weight, except in ethanol treatment, where suppression was observed. HWD showed higher TSS and acidity than that of control. The least browning was observed in ethanol treatment. The total plate count was not significantly affected by various treatments. Overall acceptability under various treatments decreased during storage period both at room and low temperature. Hot water and ethanol vapour treated sprouts showed higher acceptability than other treatments. However, the acceptability scores for sprouts remained within the acceptable range (≥6) up to 72 h at room temperature and 120 h at low temperature conditions. PMID:25328209

  20. A review of exposure conditions and possible health effects associated with aerosol and vapour from low-aromatic oil-based drilling fluids.

    PubMed

    Eide, I

    1990-04-01

    This paper reviews investigations on possible health effects after inhalation of aerosol and vapour from the low-aromatic oil-based drilling fluids which have replaced the diesel-based fluids. The main advantage of the low-aromatic base oils with respect to health hazard is their lower volatility. However, some aliphatic and naphthenic hydrocarbons are distributed more efficiently to the brain than are the corresponding aromatic ones. Reducing the content of aromatic hydrocarbons becomes particularly important when the upper end of the boiling point range is sufficiently high for the base oil to contain carcinogenic polycyclic aromatic hydrocarbons (PAH). As a result of enclosure and local extract ventilation it has been possible to reduce time-weighted average concentrations of aerosol and vapour to below 100 mg m-3. Effects on the central nervous system have only been observed at higher concentrations of the actual hydrocarbons, and male rat hydrocarbon nephropathy is not considered predictive of a normal human response. Insufficient information is available on possible long-term effects of exposure to the low-aromatic oil-based drilling fluids, especially regarding carcinogenicity and changes in the lungs. PMID:2205144

  1. Scale effects on the controls on mountain grassland leaf stomatal and ecosystem surface conductance to water vapour

    NASA Astrophysics Data System (ADS)

    Haslwanter, Alois; Hammerle, Albin; Wohlfahrt, Georg

    2010-05-01

    Stomata are the major pathway by which plants exert control on the exchange of trace gases and water vapour with the aerial environment and thus provide a key link between the functioning of terrestrial ecosystems and the state and composition of the atmosphere. Understanding the nature of this control, i.e. how stomatal conductance differs between plant species and ecosystems and how it varies in response to external and internal forcings, is key to predicting feedbacks plants may be providing to changing climatic conditions. Despite a long history of research on stomatal functioning, a fully mechanistic understanding of how stomata function in response to biotic and abiotic controls is still elusive which has led to the development of a large number of (semi-)empirical models of varying complexity. Two of the most widely used models go back to Jarvis (1976) and Ball, Woodrow and Berry (1987), termed J-model and BWB-model, respectively, in the following. The J-model simulates stomatal conductance as some maximal value attenuated by a series of multiplicative functions which are bound between zero and unity, while the BWB-model predicts stomatal conductance as a linear function of photosynthesis, relative humidity and carbon dioxide concentration in the leaf boundary layer. Both models were developed for the prediction of leaf-scale stomatal conductance to water vapour, but have been applied for simulating ecosystem-scale surface conductance as well. The objective of the present paper is to compare leaf- and ecosystem-scale conductances to water vapour and to assess the respective controls using the two above-mentioned models as analysis frameworks. To this end leaf-level stomatal conductance has been measured by means of leaf-gas exchange methods and ecosystem-scale surface conductance by inverting eddy covariance evapotranspiration estimates at a mountain grassland site in Austria. Our major findings are that the proportionality parameter in the BWB-model is

  2. 57. PHOTOCOPY OF DRAWING AMMONIA LEACHING PLANT GENERAL, DOUBLE EFFECT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    57. PHOTOCOPY OF DRAWING AMMONIA LEACHING PLANT GENERAL, DOUBLE EFFECT EVAPORATOR UNIT - Kennecott Copper Corporation, On Copper River & Northwestern Railroad, Kennicott, Valdez-Cordova Census Area, AK

  3. 56. PHOTOCOPY OF DRAWING AMMONIA LEACHING PLANT GENERAL, DOUBLE EFFECT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    56. PHOTOCOPY OF DRAWING AMMONIA LEACHING PLANT GENERAL, DOUBLE EFFECT EVAPORATOR UNIT - Kennecott Copper Corporation, On Copper River & Northwestern Railroad, Kennicott, Valdez-Cordova Census Area, AK

  4. Double peak sensory responses: effects of capsaicin.

    PubMed

    Aprile, I; Tonali, P; Stalberg, E; Di Stasio, E; Caliandro, P; Foschini, M; Vergili, G; Padua, L

    2007-10-01

    The aim of this study is to verify whether degeneration of skin receptors or intradermal nerve endings by topical application of capsaicin modifies the double peak response obtained by submaximal anodal stimulation. Five healthy volunteers topically applied capsaicin to the finger-tip of digit III (on the distal phalanx) four times daily for 4-5 weeks. Before and after local capsaicin applications, we studied the following electrophysiological findings: compound sensory action potential (CSAP), double peak response, sensory threshold and double peak stimulus intensity. Local capsaicin application causes disappearance or decrease of the second component of the double peak, which gradually increases after the suspension of capsaicin. Conversely, no significant differences were observed for CSAP, sensory threshold and double peak stimulus intensity. This study suggests that the second component of the double peak may be a diagnostic tool suitable to show an impairment of the extreme segments of sensory nerve fibres in distal sensory axonopathy in the early stages of damage, when receptors or skin nerve endings are impaired but undetectable by standard nerve conduction studies.

  5. Spin effects in double photoionization of lithium

    SciTech Connect

    Kheifets, A. S.; Fursa, D. V.; Hines, C. W.; Bray, I.; Colgan, J.; Pindzola, M. S.

    2010-02-15

    We apply the nonperturbative convergent close-coupling (CCC) and time-dependent close coupling (TDCC) formalisms to calculate fully differential energy and angular resolved cross sections of double photoionization (DPI) of lithium. The equal energy sharing case is considered in which dynamics of the DPI process can be adequately described by two symmetrized singlet and triplet amplitudes. The angular width of these amplitudes serves as a measure of the strength of the angular correlation between the two ejected electrons. This width is interpreted in terms of the spin of the photoelectron pair.

  6. A randomised, crossover study on an electronic vapour product, a nicotine inhalator and a conventional cigarette. Part B: Safety and subjective effects.

    PubMed

    Walele, Tanvir; Sharma, Girish; Savioz, Rebecca; Martin, Claire; Williams, Josie

    2016-02-01

    An Electronic Vapour Product (EVP) has been evaluated for short-term safety parameters and subjective effects in a 2-part study, in smokers. Part 1 compared the EVP with unflavoured (UF) and flavoured (FL) e-liquid at 2.0% nicotine to a conventional cigarette (CC; JPS Silver King Size, 0.6 mg) and a licensed nicotine inhalator (Nicorette(®), 15 mg). Part 2 assessed the effect of increasing concentrations of nicotine in the e-liquid used with the EVP (0%, 0.4%, 0.9%, 2.0%). The study was designed as a randomised, controlled, crossover trial. Outcomes included adverse events (AEs), vital signs, exhaled carbon monoxide (CO), clinical laboratory parameters, smoking urges and withdrawal symptoms. In both study parts, only mild non-serious AEs were reported. No major differences were observed in AEs between the EVPs and Nicorette(®). Exhaled CO levels only increased for CC. All products appeared to decrease smoking urges and nicotine withdrawal symptom scores to a similar extent. The EVP had a similar short-term safety profile to Nicorette(®) and relieved smoking urges and nicotine withdrawal symptoms to a similar extent as Nicorette(®) and CC. Unlike nicotine replacement therapies, the EVP may offer an alternative for those finding it difficult to quit the behavioural and sensorial aspects of smoking.

  7. Plastic optical fibre sensor for detecting vapour phase alcohol

    NASA Astrophysics Data System (ADS)

    Morisawa, Masayuki; Amemiya, Yumiko; Kohzu, Hidenori; Liang, Chuan Xin; Muto, Shinzo

    2001-07-01

    New plastic optical fibre sensors for detecting alcohol vapour have been studied. A certain kind of polymer such as a Novolac resin causes swelling when it is exposed to alcohol vapour. This effect produces a change in the polymer refractive index. Based on this principle, the plastic optical fibre (POF) type sensor head was fabricated by coating Novolac-resin and Novolac/Fe:SO complex film as a cladding layer on the plastic fibre core. When this sensor head was exposed to ethanol and methanol vapour, the light intensity passing through the sensor head changed remarkably depending on the vapour pressure. The sensor response was also found to be fast, stable and reproducible.

  8. Surface effects of vapour-liquid-solid driven Bi surface droplets formed during molecular-beam-epitaxy of GaAsBi.

    PubMed

    Steele, J A; Lewis, R A; Horvat, J; Nancarrow, M J B; Henini, M; Fan, D; Mazur, Y I; Schmidbauer, M; Ware, M E; Yu, S-Q; Salamo, G J

    2016-01-01

    Herein we investigate a (001)-oriented GaAs1-xBix/GaAs structure possessing Bi surface droplets capable of catalysing the formation of nanostructures during Bi-rich growth, through the vapour-liquid-solid mechanism. Specifically, self-aligned "nanotracks" are found to exist trailing the Bi droplets on the sample surface. Through cross-sectional high-resolution transmission electron microscopy the nanotracks are revealed to in fact be elevated above surface by the formation of a subsurface planar nanowire, a structure initiated mid-way through the molecular-beam-epitaxy growth and embedded into the epilayer, via epitaxial overgrowth. Electron microscopy studies also yield the morphological, structural, and chemical properties of the nanostructures. Through a combination of Bi determination methods the compositional profile of the film is shown to be graded and inhomogeneous. Furthermore, the coherent and pure zincblende phase property of the film is detailed. Optical characterisation of features on the sample surface is carried out using polarised micro-Raman and micro-photoluminescence spectroscopies. The important light producing properties of the surface nanostructures are investigated through pump intensity-dependent micro-PL measurements, whereby relatively large local inhomogeneities are revealed to exist on the epitaxial surface for important optical parameters. We conclude that such surface effects must be considered when designing and fabricating optical devices based on GaAsBi alloys.

  9. Effect of water vapour condensation on the radon content in subsurface air in a hypogeal inactive-volcanic environment in Galdar cave, Spain

    NASA Astrophysics Data System (ADS)

    Fernandez-Cortes, A.; Benavente, D.; Cuezva, S.; Cañaveras, J. C.; Alvarez-Gallego, M.; Garcia-Anton, E.; Soler, V.; Sanchez-Moral, S.

    2013-08-01

    Fluctuations of trace gas activity as a response to variations in weather and microclimate conditions were monitored over a year in a shallow volcanic cave (Painted Cave, Galdar, Canary Islands, Spain). 222Rn concentration was used due to its greater sensitivity to hygrothermal variations than CO2 concentration. Radon concentration in the cave increases as effective vapour condensation within the porous system of the rock surfaces inside the cave increases due to humidity levels of more than 70%. Condensed water content in pores was assessed and linked to a reduction in the direct passage of trace gases. Fluctuations in radon activity as a response to variations in weather and microclimate conditions were statistically identified by clustering entropy changes on the radon signal and parameterised to predict radon concentration anomalies. This raises important implications for other research fields, including the surveillance of shallow volcanic and seismic activity, preventive conservation of cultural heritage in indoor spaces, indoor air quality control and studies to improve understanding of the role of subterranean terrestrial ecosystems as reservoirs and/or temporary sources of trace gases.

  10. Surface effects of vapour-liquid-solid driven Bi surface droplets formed during molecular-beam-epitaxy of GaAsBi.

    PubMed

    Steele, J A; Lewis, R A; Horvat, J; Nancarrow, M J B; Henini, M; Fan, D; Mazur, Y I; Schmidbauer, M; Ware, M E; Yu, S-Q; Salamo, G J

    2016-01-01

    Herein we investigate a (001)-oriented GaAs1-xBix/GaAs structure possessing Bi surface droplets capable of catalysing the formation of nanostructures during Bi-rich growth, through the vapour-liquid-solid mechanism. Specifically, self-aligned "nanotracks" are found to exist trailing the Bi droplets on the sample surface. Through cross-sectional high-resolution transmission electron microscopy the nanotracks are revealed to in fact be elevated above surface by the formation of a subsurface planar nanowire, a structure initiated mid-way through the molecular-beam-epitaxy growth and embedded into the epilayer, via epitaxial overgrowth. Electron microscopy studies also yield the morphological, structural, and chemical properties of the nanostructures. Through a combination of Bi determination methods the compositional profile of the film is shown to be graded and inhomogeneous. Furthermore, the coherent and pure zincblende phase property of the film is detailed. Optical characterisation of features on the sample surface is carried out using polarised micro-Raman and micro-photoluminescence spectroscopies. The important light producing properties of the surface nanostructures are investigated through pump intensity-dependent micro-PL measurements, whereby relatively large local inhomogeneities are revealed to exist on the epitaxial surface for important optical parameters. We conclude that such surface effects must be considered when designing and fabricating optical devices based on GaAsBi alloys. PMID:27377213

  11. Surface effects of vapour-liquid-solid driven Bi surface droplets formed during molecular-beam-epitaxy of GaAsBi

    PubMed Central

    Steele, J. A.; Lewis, R. A.; Horvat, J.; Nancarrow, M. J. B.; Henini, M.; Fan, D.; Mazur, Y. I.; Schmidbauer, M.; Ware, M. E.; Yu, S.-Q.; Salamo, G. J.

    2016-01-01

    Herein we investigate a (001)-oriented GaAs1−xBix/GaAs structure possessing Bi surface droplets capable of catalysing the formation of nanostructures during Bi-rich growth, through the vapour-liquid-solid mechanism. Specifically, self-aligned “nanotracks” are found to exist trailing the Bi droplets on the sample surface. Through cross-sectional high-resolution transmission electron microscopy the nanotracks are revealed to in fact be elevated above surface by the formation of a subsurface planar nanowire, a structure initiated mid-way through the molecular-beam-epitaxy growth and embedded into the epilayer, via epitaxial overgrowth. Electron microscopy studies also yield the morphological, structural, and chemical properties of the nanostructures. Through a combination of Bi determination methods the compositional profile of the film is shown to be graded and inhomogeneous. Furthermore, the coherent and pure zincblende phase property of the film is detailed. Optical characterisation of features on the sample surface is carried out using polarised micro-Raman and micro-photoluminescence spectroscopies. The important light producing properties of the surface nanostructures are investigated through pump intensity-dependent micro-PL measurements, whereby relatively large local inhomogeneities are revealed to exist on the epitaxial surface for important optical parameters. We conclude that such surface effects must be considered when designing and fabricating optical devices based on GaAsBi alloys. PMID:27377213

  12. Surface effects of vapour-liquid-solid driven Bi surface droplets formed during molecular-beam-epitaxy of GaAsBi

    NASA Astrophysics Data System (ADS)

    Steele, J. A.; Lewis, R. A.; Horvat, J.; Nancarrow, M. J. B.; Henini, M.; Fan, D.; Mazur, Y. I.; Schmidbauer, M.; Ware, M. E.; Yu, S.-Q.; Salamo, G. J.

    2016-07-01

    Herein we investigate a (001)-oriented GaAs1‑xBix/GaAs structure possessing Bi surface droplets capable of catalysing the formation of nanostructures during Bi-rich growth, through the vapour-liquid-solid mechanism. Specifically, self-aligned “nanotracks” are found to exist trailing the Bi droplets on the sample surface. Through cross-sectional high-resolution transmission electron microscopy the nanotracks are revealed to in fact be elevated above surface by the formation of a subsurface planar nanowire, a structure initiated mid-way through the molecular-beam-epitaxy growth and embedded into the epilayer, via epitaxial overgrowth. Electron microscopy studies also yield the morphological, structural, and chemical properties of the nanostructures. Through a combination of Bi determination methods the compositional profile of the film is shown to be graded and inhomogeneous. Furthermore, the coherent and pure zincblende phase property of the film is detailed. Optical characterisation of features on the sample surface is carried out using polarised micro-Raman and micro-photoluminescence spectroscopies. The important light producing properties of the surface nanostructures are investigated through pump intensity-dependent micro-PL measurements, whereby relatively large local inhomogeneities are revealed to exist on the epitaxial surface for important optical parameters. We conclude that such surface effects must be considered when designing and fabricating optical devices based on GaAsBi alloys.

  13. Effects of radiation on DNA's double helix

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The blueprint of life, DNA's double helix is found in the cells of everything from bacteria to astronauts. Exposure to radiation(depicted at right) such as X-rays (upper) or heavy ion particles (lower), can damage DNA and cause dire consequences both to the organism itself and to future generations. One of NASA's main goals is to develop better radiation shielding materials to protect astronauts from destructive radiation in space. This is particularly important for long space missions. NASA has selected researchers to study materials that provide better shielding. This research is managed by NASA's Office of Biological and Physical Research and is supported by the Microgravity Science and Applications Department at NASA's Marshall Center. During International Space Station Expedition Six, the Extravehicular Activity Radiation Monitoring (EVARM) will continue to measure radiation dosage encountered by the eyes, internal organs and skin during specific spacewalks, and relate it to the type of activity, location and other factors. An analysis of this information may be useful in mitigating potential exposure to space walkers in the future. (Illustration by Dr. Frank Cucinotta, NASA/Johnson Space Center, and Prem Saganti, Lockheed Martin)

  14. Cryopreserving turkey semen in straws and nitrogen vapour using DMSO or DMA: effects of cryoprotectant concentration, freezing rate and thawing rate on post-thaw semen quality.

    PubMed

    Iaffaldano, N; Di Iorio, M; Miranda, M; Zaniboni, L; Manchisi, A; Cerolini, S

    2016-04-01

    1. This study was designed to identify a suitable protocol for freezing turkey semen in straws exposed to nitrogen vapour by examining the effects of dimethylacetamide (DMA) or dimethylsulfoxide (DMSO) as cryoprotectant (CPA), CPA concentration, freezing rate and thawing rate on in vitro post-thaw semen quality. 2. Pooled semen samples were diluted 1:1 (v:v) with a freezing extender composed of Tselutin diluent containing DMA or DMSO to give final concentrations of 8% or 18% DMA and 4% or 10% DMSO. The semen was packaged in 0.25 ml plastic straws and frozen at different heights above the liquid nitrogen (LN2) surface (1, 5 and 10 cm) for 10 min. Semen samples were thawed at 4°C for 5 min or at 50°C for 10 s. After thawing, sperm motility, viability and osmotic tolerance were determined. 3. Cryosurvival of turkey sperm was affected by DMSO concentration. Freezing rate affected the motility of sperm cryopreserved using both CPAs, while thawing rates showed an effect on the motility of sperm cryopreserved using DMA and on the viability of sperm cryopreserved using DMSO. Significant interactions between freezing rate × thawing rate on sperm viability in the DMA protocol were found. 4. The most effective freezing protocol was the use of 18% DMA or 10% DMSO with freezing 10 cm above the LN2 surface and a thawing temperature of 50°C. An efficient protocol for turkey semen would improve prospects for sperm cryobanks and the commercial use of frozen turkey semen.

  15. The effect of water vapour on the normalized difference vegetation index derived for the Sahelian region from NOAA AVHRR data

    NASA Technical Reports Server (NTRS)

    Justice, Christopher O.; Eck, T. F.; Tanre, Didier; Holben, B. N.

    1991-01-01

    The near-infrared channel of the NOAA advanced very high resolution radiometer (AVHRR) contains a water vapor absorption band that affects the determination of the normalized difference vegetation index (NDVI). Daily and seasonal variations in atmospheric water vapor within the Sahel are shown to affect the use of the NDVI for the estimation of primary production. This water vapor effect is quantified for the Sahel by radiative transfer modeling and empirically using observations made in Mali in 1986.

  16. Interactive effects of soil water deficit and air vapour pressure deficit on mesophyll conductance to CO2 in Vitis vinifera and Olea europaea.

    PubMed

    Perez-Martin, A; Flexas, J; Ribas-Carbó, M; Bota, J; Tomás, M; Infante, J M; Diaz-Espejo, A

    2009-01-01

    The present work aims to study the interactive effect of drought stress and high vapour pressure deficit (VPD) on leaf gas exchange, and especially on mesophyll conductance to CO(2) (g(m)), in two woody species of great agronomical importance in the Mediterranean basin: Vitis vinifera L. cv. Tempranillo and Olea europaea L. cv. Manzanilla. Plants were grown in specially designed outdoor chambers with ambient and below ambient VPD, under both well-irrigated and drought conditions. g(m) was estimated by the variable J method from simultaneous measurements of gas exchange and fluorescence. In both species, the response to soil water deficit was larger in g(s) than in g(m), and more important than the response to VPD. Olea europaea was apparently more sensitive to VPD, so that plants growing in more humid chambers showed higher g(s) and g(m). In V. vinifera, in contrast, soil water deficit dominated the response of g(s) and g(m). Consequently, changes in g(m)/g(s) were more related to VPD in O. europaea and to soil water deficit in V. vinifera. Most of the limitations of photosynthesis were diffusional and especially due to stomatal closure. No biochemical limitation was detected. The results showed that structural parameters played an important role in determining g(m) during the acclimation process. Although the relationship between leaf mass per unit area (M(A)) with g(m) was scattered, it imposed a limitation to the maximum g(m) achievable, with higher values of M(A) in O. europaea at lower g(m) values. M(A) decreased under water stress in O. europaea but it increased in V. vinifera. This resulted in a negative relationship between M(A) and the CO(2) draw-down between substomatal cavities and chloroplasts in O. europaea, while being positive in V. vinifera. PMID:19457982

  17. 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...

  18. Phase transformation and quantum confinement effect in CdSe/Se multilayer thin films prepared by physical vapour deposition

    NASA Astrophysics Data System (ADS)

    Kumar, M. Melvin David; Devadason, Suganthi

    2013-12-01

    CdSe/Se multilayer (ML) thin films with different thickness ratios of Se and CdSe sublayers were prepared by using a thermal evaporation method. Prepared samples were annealed at temperature 300 K. From X-ray diffraction (XRD) studies, samples prepared at room temperature showed a (100) plane of CdSe with wurtzite structure, whereas the annealed samples confirmed the cubic structure. Stress created in ML systems was calculated from XRD data and found that it increases with decreasing particle size. The energy band gap value of a CdSe/Se ML thin film is shifted to a value higher than that of the bulk CdSe (1.74 eV) semiconductor. This is due to decrease in the crystallite size smaller than the Bohr exciton diameter of CdSe (11.2 nm). Crystallite sizes (≈5 nm) were calculated from UV-VIS data with the predictions of an effective mass approximation model. The photoluminescence peak of the ML samples is split into two bands having nearest values due to the emissions from spin-orbit split-up of the excited energy state.

  19. Evidence for a link between global lightning activity and upper tropospheric water vapour

    PubMed

    Price

    2000-07-20

    Tropospheric water vapour is a key element of the Earth's climate, which has direct effects as a greenhouse gas, as well as indirect effects through interaction with clouds, aerosols and tropospheric chemistry. Small changes in upper-tropospheric water vapour have a much larger impact on the greenhouse effect than small changes in water vapour in the lower atmosphere, but whether this impact is a positive or negative feedback remains uncertain. The main challenge in addressing this question is the difficulty in monitoring upper-tropospheric water vapour globally over long timescales. Here I show that upper-tropospheric water-vapour variability and global lightning activity are closely linked, suggesting that upper-tropospheric water-vapour changes can be inferred from records of global lightning activity, readily obtained from observations at a single location on the Earth's surface. This correlation reflects the fact that continental deep-convective thunderstorms transport large amounts of water vapour into the upper troposphere and thereby dominate the variations of global upper-tropospheric water vapour while producing most of the lightning on Earth. As global lightning induces Schumann resonances, an electromagnetic phenomenon in the atmosphere that can be observed easily at low cost, monitoring of these resonances might provide a convenient method for tracking upper-tropospheric water-vapour variability and hence contribute to a better understanding of the processes affecting climate change.

  20. Light propagation through atomic vapours

    NASA Astrophysics Data System (ADS)

    Siddons, Paul

    2014-05-01

    This tutorial presents the theory necessary to model the propagation of light through an atomic vapour. The history of atom-light interaction theories is reviewed, and examples of resulting applications are provided. A numerical model is developed and results presented. Analytic solutions to the theory are found, based on approximations to the numerical work. These solutions are found to be in excellent agreement with experimental measurements.

  1. Double-photoionization of helium including quadrupole radiation effects

    SciTech Connect

    Colgan, James; Ludlow, J A; Lee, Teck - Ghee; Pindzola, M S; Robicheaux, F

    2009-01-01

    Non-perturbative time-dependent close-coupling calculations are carried out for the double photoionization of helium including both dipole and quadrupole radiation effects. At a photon energy of 800 eV, accessible at CUlTent synchrotron light sources, the quadrupole interaction contributes around 6% to the total integral double photoionization cross section. The pure quadrupole single energy differential cross section shows a local maxima at equal energy sharing, as opposed to the minimum found in the pure dipole single energy differential cross section. The sum of the pure dipole and pure quadrupole single energy differentials is insensitive to non-dipole effects at 800 eV. However, the triple differential cross section at equal energy sharing of the two ejected electrons shows strong non-dipole effects due to the quadrupole interaction that may be experimentally observable.

  2. 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.

  3. Specific ion effects via ion hydration: II. Double layer interaction.

    PubMed

    Ruckenstein, Eli; Manciu, Marian

    2003-09-18

    A simple modified Poisson-Boltzmann formalism, which accounts also for those interactions between electrolyte ions and colloidal particles not included in the mean potential, is used to calculate the force between two parallel plates. It is shown that the short-range interactions between ions and plates, such as those due to the change in the hydration free energy of a structure-making/breaking ion that approaches the interface, affect the double layer interaction at large separations through the modification of the surface potential and surface charge density. While at short separations (below the range of the short-range ion-hydration forces) the interaction can be attractive, at larger separations the interaction is always repulsive, as in the traditional theory. When the long-range van der Waals interactions between the ions and the system (ion-dispersion interactions) are accounted for in the modified Poisson-Boltzmann approach, an attractive force between plates can be generated. At sufficiently large separations, this attraction can become even stronger than the traditional van der Waals attraction between plates of finite thickness, thus generating a dominant long-range 'double layer attraction'. At small plate separations, the attraction generated by the ion-dispersion forces combined with the electrostatic repulsion due to the double layers overlap can lead to a variety of interactions, from a weak attraction (which is typically by at least one order of magnitude smaller than the traditional van der Waals attraction between plates) to a strong double layer repulsion (for sufficiently large surface charges). Both types of ion interactions (long-range van der Waals or short-range ionic hydration) strongly affect the magnitude of the double layer interaction, and can account for the specific ion effects observed experimentally. However, they do not affect qualitatively the traditional theory of the colloid stability, which predicts that the colloid is stable

  4. Moral absolutism and the double-effect exception: reflections on Joseph Boyle's Who is entitled to double effect?

    PubMed

    Donagan, A

    1991-10-01

    Joseph Boyle raises important questions about the place of the double-effect exception in absolutist moral theories. His own absolutist theory (held by many, but not all, Catholic moralists), which derives from the principles that fundamental human goods may not be intentionally violated, cannot dispense with such exceptions, although he rightly rejects some widely held views about what they are. By contrast, Kantian absolutist theory, which derives from the principle that lawful freedom must not be violated, has a corollary--that it is a duty, where possible, to coerce those who try to violate lawful freedom--which makes superfluous many of the double-effect exceptions Boyle allows. Other implications of the two theories are contrasted. Inter alia, it is argued that, in Boyle's theory, that a violation of a fundamental human good can be viewed as a cost proportionate to a benefit obtained, cannot yield a double-effect exception to the prohibition of intentionally violating that good, because paying a cost cannot be unintentional.

  5. Moral absolutism and the double-effect exception: reflections on Joseph Boyle's Who is entitled to double effect?

    PubMed

    Donagan, A

    1991-10-01

    Joseph Boyle raises important questions about the place of the double-effect exception in absolutist moral theories. His own absolutist theory (held by many, but not all, Catholic moralists), which derives from the principles that fundamental human goods may not be intentionally violated, cannot dispense with such exceptions, although he rightly rejects some widely held views about what they are. By contrast, Kantian absolutist theory, which derives from the principle that lawful freedom must not be violated, has a corollary--that it is a duty, where possible, to coerce those who try to violate lawful freedom--which makes superfluous many of the double-effect exceptions Boyle allows. Other implications of the two theories are contrasted. Inter alia, it is argued that, in Boyle's theory, that a violation of a fundamental human good can be viewed as a cost proportionate to a benefit obtained, cannot yield a double-effect exception to the prohibition of intentionally violating that good, because paying a cost cannot be unintentional. PMID:1779209

  6. Sandwich double gate vertical tunneling field-effect transistor

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Zhang, Wen-hao; Yu, Cheng-hao; Cao, Fei

    2016-05-01

    In this work, a sandwich vertical tunnel field effect transistor (SDG-VTFET) is presented and studied. Since the dominant carrier tunneling of SDG-VFET occurs in a direction that is in line with the gate field, high ON-state current and steep subthreshold slope are observed. Comparisons between SDG-VFET and double gate tunnel field effect transistor are made to clarify advantages of SDG-VTFET. The simulation results of our work show that SDG-VTFET has stronger gate control, steeper subthreshold slope and higher ON-state current. The device plays a promising candidate for future low power circuit applications.

  7. Ellipsometry study of (0001) cadmium crystal faces during vapour growth

    NASA Astrophysics Data System (ADS)

    Gauch, M.; Quentel, G.

    1981-07-01

    Ellipsometry analysis of (0001) cadium faces during vapour growth reveal periodic fluctuations of the dielectric constant which are related to supersaturation. We show that they can be interpreted by the instability of monoatomic step trains produced by spiral growth. Such a model of surface roughness is also treated using the effective medium approximation of Bruggeman, which corroborates the experimental results.

  8. The theoretical tenability of the doctrine of double effect.

    PubMed

    Bole, T J

    1991-10-01

    The doctrine of double effect shows that for which the moral agent is responsible, by explicating the relationship between the act directly intended and the consequences of that act. I contend that this doctrine is necessary not only for natural law absolutism, but also for Donagan's Kantianism and for Quinn's revised construal of the doctrine, and even for consequentialism, as bioethical implications of the doctrine make clear. For those who do not accept this necessity, I contend that it is necessary metatheoretically, in order to deal with those moral agents with irreconcilably different notions of the morally good.

  9. The theoretical tenability of the doctrine of double effect.

    PubMed

    Bole, T J

    1991-10-01

    The doctrine of double effect shows that for which the moral agent is responsible, by explicating the relationship between the act directly intended and the consequences of that act. I contend that this doctrine is necessary not only for natural law absolutism, but also for Donagan's Kantianism and for Quinn's revised construal of the doctrine, and even for consequentialism, as bioethical implications of the doctrine make clear. For those who do not accept this necessity, I contend that it is necessary metatheoretically, in order to deal with those moral agents with irreconcilably different notions of the morally good. PMID:1779207

  10. Vapour-liquid equilibrium relationship between toluene and mixed surfactants.

    PubMed

    Tian, Senlin; Li, Yingjie; Mo, Hong; Ning, Ping

    2012-01-01

    Micellar partitioning of volatile organic compounds (VOCs) in surfactant solutions and its effects on vapour-liquid equilibrium is fundamental to the overall design and implementation ofsurfactant-enhanced remediation. Knowledge of the vapour-liquid equilibrium partitioning coefficients for VOCs, especially in contaminated soils and groundwater in which they exist, is required. Headspace experiments were performed to quantify the effect of three mixed surfactants, cetyltrimethyl ammonium bromide (CTMAB) with tetrabutylammonium bromide (TBAB), sodium dodecyl sulphate (SDS) with Triton X-405 (TX405), and CTMAB with Triton X-100 (TX100), on the apparent Henry's constants (Hc) of toluene at temperatures ranging from 25 degrees C to 40 degrees C. The Hc values were significantly reduced in the presence of all three mixed surfactants at concentrations above their critical micelle concentrations (CMC). Mixed micellar partitioning, showing effects on the vapour-liquid equilibrium of toluene, was primarily responsible for the significant reduction of Hc in their mixed systems. The mixed surfactants CTMAB-TX100 had the greatest effect on Hc above the CMC, followed by SDS-TX405, then CTMAB-TBAB. Mixed systems of CTMAB-TX100 decreased Hc at concentrations significantly lower than the SDS-TX405 and CTMAB-TBAB concentrations, because of to the lower CMC of CTMAB-TX100. Vapour-liquid equilibrium data were also tested against the model (Hc = H/(1 + K(X - CMC)) that described the partitioning of VOCs in vapour-water-micelle phases. The correlation of Hc with mixed surfactant concentrations (X) and CMC can be utilized as an effective tool to predict the Hc by mixed surfactants. PMID:22988616

  11. Vapour-liquid equilibrium relationship between toluene and mixed surfactants.

    PubMed

    Tian, Senlin; Li, Yingjie; Mo, Hong; Ning, Ping

    2012-01-01

    Micellar partitioning of volatile organic compounds (VOCs) in surfactant solutions and its effects on vapour-liquid equilibrium is fundamental to the overall design and implementation ofsurfactant-enhanced remediation. Knowledge of the vapour-liquid equilibrium partitioning coefficients for VOCs, especially in contaminated soils and groundwater in which they exist, is required. Headspace experiments were performed to quantify the effect of three mixed surfactants, cetyltrimethyl ammonium bromide (CTMAB) with tetrabutylammonium bromide (TBAB), sodium dodecyl sulphate (SDS) with Triton X-405 (TX405), and CTMAB with Triton X-100 (TX100), on the apparent Henry's constants (Hc) of toluene at temperatures ranging from 25 degrees C to 40 degrees C. The Hc values were significantly reduced in the presence of all three mixed surfactants at concentrations above their critical micelle concentrations (CMC). Mixed micellar partitioning, showing effects on the vapour-liquid equilibrium of toluene, was primarily responsible for the significant reduction of Hc in their mixed systems. The mixed surfactants CTMAB-TX100 had the greatest effect on Hc above the CMC, followed by SDS-TX405, then CTMAB-TBAB. Mixed systems of CTMAB-TX100 decreased Hc at concentrations significantly lower than the SDS-TX405 and CTMAB-TBAB concentrations, because of to the lower CMC of CTMAB-TX100. Vapour-liquid equilibrium data were also tested against the model (Hc = H/(1 + K(X - CMC)) that described the partitioning of VOCs in vapour-water-micelle phases. The correlation of Hc with mixed surfactant concentrations (X) and CMC can be utilized as an effective tool to predict the Hc by mixed surfactants.

  12. Breakdown and dc discharge in low-pressure water vapour

    NASA Astrophysics Data System (ADS)

    Sivoš, J.; Škoro, N.; Marić, D.; Malović, G.; Petrović, Z. Lj

    2015-10-01

    In this paper we report studies of basic properties of breakdown, low-current Townsend discharge and high-current discharge regimes in water vapour. Paschen curves and the corresponding distributions of emission intensities at low current were recorded in the range of pd (pressure x electrode gap) from 0.1 to 10 Torrcm covering the region of Paschen minimum. From the experimental profiles we obtained effective ionization coefficient of water vapour for the E/N range 650 Td-7 kTd and fitted the results by using the extended Townsend analytical formula. Using the obtained ionization coefficient, we calculated the effective yield of secondary electrons from the copper cathode. Results of the measurements of Volt-Ampere characteristics in water vapour were presented together with the images of the axial structure of the discharge in a wide range of discharge currents for two pd values. Recorded profiles showed development of the spatial structure of the discharge in different operating regimes. We were able to identify conditions where processes induced by heavy particles, probably fast hydrogen atoms, are dominant in inducing emission from the discharge. Finally, standard scaling laws were tested for low current and glow discharges in water vapour.

  13. Detection of explosive vapour using surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Fang, X.; Ahmad, S. R.

    2009-11-01

    A commercially available nano-structured gold substrate was used for activating surface-enhanced Raman scattering (SERS). Raman spectra of the vapour of explosive material, triacetonetriperoxide (TATP), at trace concentrations produced from adsorbed molecules on such surfaces have been studied. Prominent Raman lines of the explosive molecular species were recorded at a sample temperature of ˜35°C, which is near to human body temperature. For this study, the concentration of the adsorbed TATP molecules on the nano-structured surface was varied by heating the sample to different temperatures and exposing the substrate to the sample vapour for different lengths of time. The intensities of the Raman lines have been found to increase with the increase in temperature and also with the increase in the duration of exposure for a fixed temperature. However, as expected, the Raman intensities have been found to saturate at higher temperatures and longer exposures. These saturation effects of the strengths of the Raman lines in the SERS of TATP vapour have been investigated in this paper. The results indicate that the optimisation for vapour deposition on the surface could be a crucial factor for any quantitative estimate of the concentration of the molecular species adsorbed on the nano-structured substrates.

  14. Double Photoionization of Beryllium atoms using Effective Charge approximation

    NASA Astrophysics Data System (ADS)

    Saha, Haripada

    2016-05-01

    We plan to report the results of our investigation on double photoionization K-shell electrons from Beryllium atoms. We will present the results of triple differential cross sections at excess energy of 20 eV using our recently extended MCHF method. We will use multiconfiguration Hartree Fock method to calculate the wave functions for the initial state. The final state wave functions will be obtained in the angle depended Effective Charge approximation which accounts for electron correlation between the two final state continuum electrons. We will discuss the effect of core correlation and the valence shell electrons in the triple differential cross section. The results will be compared with the available accurate theoretical calculations and experimental findings.

  15. Effective Hamiltonian for the hybrid double quantum dot qubit

    NASA Astrophysics Data System (ADS)

    Ferraro, E.; De Michielis, M.; Mazzeo, G.; Fanciulli, M.; Prati, E.

    2014-05-01

    Quantum dot hybrid qubits formed from three electrons in double quantum dots represent a promising compromise between high speed and simple fabrication for solid state implementations of single-qubit and two-qubits quantum logic ports. We derive the Schrieffer-Wolff effective Hamiltonian that describes in a simple and intuitive way the qubit by combining a Hubbard-like model with a projector operator method. As a result, the Hubbard-like Hamiltonian is transformed in an equivalent expression in terms of the exchange coupling interactions between pairs of electrons. The effective Hamiltonian is exploited to derive the dynamical behavior of the system and its eigenstates on the Bloch sphere to generate qubits operation for quantum logic ports. A realistic implementation in silicon and the coupling of the qubit with a detector are discussed.

  16. Water vapour in the UT/LS

    NASA Astrophysics Data System (ADS)

    Schiller, C.

    2003-04-01

    The water vapour abundance increased at all levels in the stratosphere during the last decades. Though the observed increase cannot be explained quantitatively, the water vapour distribution and underlying processes seem to be sufficiently understood in the overworld. In the lowermost stratosphere and in the tropical tropopause layer, however, the complex transport and temperature patterns on different scales result in a high variability and strong gradients of the water vapour distribution. The long-term increase of water vapour seems to be apparent also in the lowermost stratosphere, but its significance is decreasing towards the tropopause. In this presentation, measurements of water vapour in the extratropical UT/LS from several airborne campaigns are discussed and compared to distribution patterns obtained from satellite data sets. A mixing layer with H2O mixing ratios up to 100 ppmv is found above the tropopause, frequently resulting in saturation of these air masses. A seasonal cycle of the water content with a late spring and summer maximum is apparent in the LS. The role of jet streams moistening the lowermost stratosphere will be discussed. In a second part, water vapour distributions in the tropics as the stratospheric source region are presented. As an example, measurements over the Indian ocean are discussed where temperatures and water vapour mixing ratios as low as in the classical 'fountain' region over Micronesia occurred. Frequently, ongoing dehydration was observed in the TTL up to the tropopause, independent on deep convection cells.

  17. Classical two-slit interference effects in double photoionization of molecular hydrogen at high energies

    NASA Astrophysics Data System (ADS)

    Horner, D. A.; Miyabe, S.; Rescigno, T. N.; McCurdy, C. W.; Morales, F.; Martín, F.

    2009-11-01

    We report a thorough theoretical study of one photon double ionization of H2 ([6]). We suggest that interference effects reported in one photon ionization will be reproducible in the case of double ionization when one of the photons carries most of the available energy and the other electron is not observed. These calculations reproduce recent double photoionization experiments of HH2 ([3]).

  18. 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

  19. Effect of cancellation in neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Mitra, Manimala; Pascoli, Silvia; Wong, Steven

    2014-11-01

    In light of recent experimental results, we carefully analyze the effects of interference in neutrinoless double beta decay, when more than one mechanism is operative. If a complete cancellation is at work, the half-life of the corresponding isotope is infinite, and any constraint on it will automatically be satisfied. We analyze this possibility in detail assuming a cancellation in Xe 136 , and find its implications on the half-life of other isotopes, such as Ge 76 . For definiteness, we consider the role of light and heavy sterile neutrinos. In this case, the effective Majorana mass parameter can be redefined to take into account all contributions, and its value gets suppressed. Hence, larger values of neutrino masses are required for the same half-life. The canonical light neutrino contribution cannot saturate the present limits of half-lives or the positive claim of observation of neutrinoless double beta decay, once the stringent bounds from cosmology are taken into account. For the case of cancellation, where all the sterile neutrinos are heavy, the tension between the results from neutrinoless double beta decay and cosmology becomes more severe. We show that the inclusion of light sterile neutrinos in this setup can resolve this issue. Using the recent results from GERDA, we derive upper limits on the active-sterile mixing angles and compare them with the case of no cancellation. The required values of the mixing angles become larger, if a cancellation is at work. A direct test of destructive interference in Xe 136 is provided by the observation of this process in other isotopes, and we study in detail the correlation between their half-lives. Finally, we discuss the model realizations which can accommodate light and heavy sterile neutrinos and the cancellation. We show that sterile neutrinos of few hundred MeV or GeV mass range, coming

  20. Molecular crowding effects on stability of DNA double helix

    NASA Astrophysics Data System (ADS)

    Singh, Amar; Singh, Navin

    2016-05-01

    Cellular environmental conditions critically affect the structure and stability of double stranded DNA (dsDNA) molecule. It is known that 20-30% of the total volume of the cell is occupied by the molecular crowders. The presence of these crowders, reduces the free space available to the base pairs of a DNA molecule, hence the movement of base pair is restricted. Here, we study the thermal opening of dsDNA molecule using Peyrard Bishop Dauxois (PBD) model. The presence of crowders in the model, that mimic those found in the cell nucleus, is realized through the potential term. Using the equilibrium statistical calculations, we find melting profile and melting probabilities of the chain. The opening of DNA molecule in the presence of these crowders is shown through the density plots. This study reveals that the stability of dsDNA molecule is influenced by entropic as well as enthalpic effects and is more stable in the crowded environment.

  1. Effect of oxygen plasma on field emission characteristics of single-wall carbon nanotubes grown by plasma enhanced chemical vapour deposition system

    NASA Astrophysics Data System (ADS)

    Kumar, Avshish; Parveen, Shama; Husain, Samina; Ali, Javid; Zulfequar, Mohammad; Harsh; Husain, Mushahid

    2014-02-01

    Field emission properties of single wall carbon nanotubes (SWCNTs) grown on iron catalyst film by plasma enhanced chemical vapour deposition system were studied in diode configuration. The results were analysed in the framework of Fowler-Nordheim theory. The grown SWCNTs were found to be excellent field emitters, having emission current density higher than 20 mA/cm2 at a turn-on field of 1.3 V/μm. The as grown SWCNTs were further treated with Oxygen (O2) plasma for 5 min and again field emission characteristics were measured. The O2 plasma treated SWCNTs have shown dramatic improvement in their field emission properties with emission current density of 111 mA/cm2 at a much lower turn on field of 0.8 V/μm. The as grown as well as plasma treated SWCNTs were also characterized by various techniques, such as scanning electron microscopy, high resolution transmission electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy before and after O2 plasma treatment and the findings are being reported in this paper.

  2. Effect of operating temperature on transient behaviour of a biofilter treating waste-air containing n-butanol vapour during intermittent loading.

    PubMed

    Feizi, Farzaneh; Nasernejad, Bahram; Zamir, Seyed Morteza

    2016-01-01

    Transient-state removal of n-butanol vapour was investigated in a biofilter (BF) packed with compost and lava rock at different operating temperatures in the range of 30-45°C under intermittent loading (8 h per day). Adsorption on the inactive bed and biodegradation in the microbial-active bed were studied separately at an empty bed residence time (EBRT) of 1 min and inlet concentrations of 2.6-3.2 g m(-3), respectively. According to the transient experiments, the highest removal efficiency (RE) around 86% was obtained at 40°C due to a high microbial activity. Comparison of CO2 production and pure adsorption of n-butanol showed that adsorption was the major mechanism in the start-up of BF at each operating condition; although the impact of adsorption declined as temperature increased from 30°C to 45°C. The process was reaction limited at all operating conditions. Based on the determination of stoichiometric coefficients of n-butanol biodegradation, the CO2 production level was significantly lower than that of the chemical oxidation process which resulted in a decrease in environmental pollution.

  3. Effect of oxygen plasma on field emission characteristics of single-wall carbon nanotubes grown by plasma enhanced chemical vapour deposition system

    SciTech Connect

    Kumar, Avshish; Parveen, Shama; Husain, Samina; Ali, Javid; Zulfequar, Mohammad; Harsh; Husain, Mushahid

    2014-02-28

    Field emission properties of single wall carbon nanotubes (SWCNTs) grown on iron catalyst film by plasma enhanced chemical vapour deposition system were studied in diode configuration. The results were analysed in the framework of Fowler-Nordheim theory. The grown SWCNTs were found to be excellent field emitters, having emission current density higher than 20 mA/cm{sup 2} at a turn-on field of 1.3 V/μm. The as grown SWCNTs were further treated with Oxygen (O{sub 2}) plasma for 5 min and again field emission characteristics were measured. The O{sub 2} plasma treated SWCNTs have shown dramatic improvement in their field emission properties with emission current density of 111 mA/cm{sup 2} at a much lower turn on field of 0.8 V/μm. The as grown as well as plasma treated SWCNTs were also characterized by various techniques, such as scanning electron microscopy, high resolution transmission electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy before and after O{sub 2} plasma treatment and the findings are being reported in this paper.

  4. Effect of gas flow rates on the anatase-rutile transformation temperature of nanocrystalline TiO2 synthesised by chemical vapour synthesis.

    PubMed

    Ahmad, Md Imteyaz; Bhattacharya, S S; Fasel, Claudia; Hahn, Horst

    2009-09-01

    Of the three crystallographic allotropes of nanocrystalline titania (rutile, anatase and brookite), anatase exhibits the greatest potential for a variety of applications, especially in the area of catalysis and sensors. However, with rutile being thermodynamically the most stable phase, anatase tends to transform into rutile on heating to temperatures in the range of 500 degrees C to 700 degrees C. Efforts made to stabilize the anatase phase at higher temperatures by doping with metal oxides suffer from the problems of having a large amorphous content on synthesis as well as the formation of secondary impurity phases on doping. Recent studies have suggested that the as-synthesised phase composition, crystallite size, initial surface area and processing conditions greatly influence the anatase to rutile transformation temperature. In this study nanocrystalline titania was synthesised in the anatase form bya chemical vapour synthesis (CVS) method using titanium tetra iso-propoxide (TTIP) as a precursor under varying flow rates of oxygen and helium. The anatase to rutile transformation was studied using high temperature X-ray diffraction (HTXRD) and simultaneous thermogravimetric analysis (STA), followed by transmission electron microscopy (TEM). It was demonstrated that the anatase-rutile transformation temperatures were dependent on the oxygen to helium flow rate ratio during CVS and the results are presented and discussed. PMID:19928267

  5. Modelling of metal vapour in pulsed TIG including influence of self-absorption

    NASA Astrophysics Data System (ADS)

    Iwao, Toru; Mori, Yusuke; Okubo, Masato; Sakai, Tadashi; Tashiro, Shinichi; Tanaka, Manabu; Yumoto, Motoshige

    2010-11-01

    Pulsed TIG (tungsten inert gas) welding is used to improve the stability and speed of arc welding, and to allow greater control over the heat input to the weld. The temperature and the radiation power density of the pulsed arc vary as a function of time, as does the distribution of metal vapour, and its effects on the arc. A self-consistent two-dimensional model of the arc and electrodes is used to calculate the properties of the arc as a function of time. Self-absorption of radiation is treated by two methods, one taking into account absorption of radiation only within the control volume of emission, and the other taking into account absorption throughout the plasma. The relation between metal vapour and radiation power density is analysed by calculating the iron vapour distribution. The results show that the transport of iron vapour is strongly affected by the fast convective flow during the peak current period. During the base current period, the region containing a low concentration of metal vapour expands because of the low convective flow. The iron vapour distribution does not closely follow the current pulses. The temperature, iron vapour and radiation power density distributions depend on the self-absorption model used. The temperature distribution becomes broader when self-absorption of radiation from all directions is considered.

  6. Liquid vapour spinodal of pure helium 4

    NASA Astrophysics Data System (ADS)

    Imre, Attila R.; Kraska, Thomas

    2008-10-01

    Unlike gases, liquids can be overheated or stretched only up to a limit. The determination of the mean-field thermodynamic stability limit-the so-called spinodal-is a very difficult theoretical and a more-or-less impossible experimental task. Based on a recent semi-empirical method, the spinodal pressure of helium-4 at given temperature is determined, using liquid-vapour surface tension, interface thickness and vapour pressure data.

  7. Phonon effects on the double mass differences in magic nuclei

    NASA Astrophysics Data System (ADS)

    Saperstein, E. E.; Baldo, M.; Gnezdilov, N. V.; Tolokonnikov, S. V.

    2016-03-01

    Odd-even double mass differences (DMDs) of magic nuclei are found within an approach starting from the free N N interaction, accounting for particle-phonon coupling (PC) effects. We consider three PC effects: the phonon-induced effective interaction, the renormalization of the "ends" due to the pole PC contribution to the nucleon mass operator, and the change of the single-particle energies. The perturbation theory in gL2, where gL is the vertex of the creation of the L -multipole phonon, is used for PC calculations. PC corrections to single-particle energies are found with an approximate accounting for the tadpole diagram. Results for magic Ca,4840, Ni,7856, Sn,132100, and 208Pb nuclei are presented. For the lighter part of this set of nuclei, from 40Ca to 56Ni, the cases divide approximately in half, between those where the PC corrections to DMD values are in good agreement with the data and the ones with the opposite result. In the major part of the cases of worsening description of DMD, a poor applicability of the perturbation theory for the induced interaction is the most probable reason of the phenomenon. For intermediate nuclei, 78Ni and 100Sn, there are no sufficiently accurate data on masses of nuclei necessary for finding DMD values. Finally, for heavier nuclei, 132Sn and 208Pb, PC corrections always result in better agreement with experiment.

  8. Water Vapour Profiles from SCIAMACHY Solar Occultation Measurements derived with Onion Peeling DOAS

    NASA Astrophysics Data System (ADS)

    Noël, S.; Bramstedt, K.; Rozanov, A.; Bovensmann, H.; Burrows, J. P.

    2009-04-01

    Water vapour is the most important greenhouse gas and plays a key role in atmospheric chemistry and transport. Most of the water vapour is located in the troposphere where it significantly contributes to weather and climate. Because the tropopause acts as a cold trap, the water vapour density in the stratosphere is significantly lower and decreases rapidly with increasing altitude. However, the amount of stratospheric water vapour plays an important role in the generation of Polar Stratospheric Clouds (PSCs), which in turn influence strongly the amount of ozone in polar regions. Trends in stratospheric water vapour are determined by methane oxidation, transport through the tropopause and by the Brewer-Dobson circulation. To seperate the various effects there is a clear need for global long term measurements of lower stratospheric water vapour, which can be provided by satellite measurements. A new retrieval method (called "Onion Peeling DOAS") has been developed to derive water vapour number density profiles from solar occultation measurements of the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY). This method is intentionally kept simple and based on a combination of an onion peeling approach with a modified DOAS (Differential Optical Absorption Spectroscopy) fit in the wavelength region around 940 nm. The resulting water vapour profiles currently cover the altitude range 15-50 km. Here, first retrieval results and comparisons of the SCIAMACHY profiles with water vapour data provided by the Atmospheric Chemistry Explorer Fourier Transform Spectrometer (ACE-FTS) and model data of the European Centre for Medium Range Weather Forecasts (ECMWF) are shown.

  9. Double-effect reasoning and the conception of human embryos.

    PubMed

    Murphy, Timothy F

    2013-08-01

    Some commentators argue that conception signals the onset of human personhood and that moral responsibilities toward zygotic or embryonic persons begin at this point, not the least of which is to protect them from exposure to death. Critics of the conception threshold of personhood ask how it can be morally consistent to object to the embryo loss that occurs in fertility medicine and research but not object to the significant embryo loss that occurs through conception in vivo. Using that apparent inconsistency as a starting point, they argue that if that embryo loss is tolerable as a way of conceiving children, it should be tolerable in fertility medicine and human embryonic research. Double-effect reasoning shows, by contrast, that conception in vivo is justified even if it involves the death of persons because the motives for wanting children are not inherently objectionable, because the embryo loss that occurs in unassisted conception is not the means by which successful conception occurs, and because the effect of having children is proportionate to the loss involved. A similar outcome holds true for in vitro fertilisation in fertility medicine but not for in vitro fertilisation for research involving human embryos.

  10. Influence of metal vapour on arc temperatures in gas-metal arc welding: convection versus radiation

    NASA Astrophysics Data System (ADS)

    Murphy, Anthony B.

    2013-06-01

    The presence of metal vapour in gas-metal arc welding has been shown to have two strong effects on the arc plasma: a decrease in temperature throughout the arc, and the formation of a local temperature minimum near the arc axis. These effects have been attributed, on the basis of different computational models, to either the increased radiative emission associated with the presence of metal vapour in the arc plasma, or the influence of the metal vapour influx on convective flow in the arc. This question is investigated using a three-dimensional computational model in which the production and the transport of metal vapour are taken into account self-consistently. Parameters relevant to welding of thin sheets of aluminum are examined. For these conditions, it is found that the first effect (the decrease in temperature throughout the arc) is due to both the increased radiative emission and the influence of the metal vapour influx on flow. The second effect (the local temperature minimum, which in this case occurs just below the wire electrode) is a consequence of the influence of aluminum vapour produced from the wire electrode on flow in the arc. By examining published results and the energy balance in the plasma, it is shown that for welding of steel with higher arc currents, the increased radiative emission can lead to a local temperature minimum at a greater distance from the wire electrode.

  11. 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.

  12. Double-effect absorption heat pump, phase 3

    NASA Astrophysics Data System (ADS)

    Cook, F. B.; Cremean, S. P.; Jatana, S. C.; Johnson, R. A.; Malcosky, N. D.

    1987-06-01

    The RD&D program has resulted in design, development and testing of a packaged prototype double-effect generator cycle absorption gas heat pump for the residential and small commercial markets. The 3RT heat pump prototype has demonstrated a COPc of 0.82 and a COPh of 1.65 at ARI rating conditions. The heat pump prototype includes a solid state control system with built-in diagnostics. The absorbent/refrigerant solution thermophysical properties were completely characterized. Commercially available materials of construction were identified for all heat pump components. A corrosion inhibitor was identified and tested in both static and dynamic environments. The safety of the heat pump was analyzed by using two analytical approaches. Pioneer Engineering estimated the factory standard cost to produce the 3RT heat pump at $1,700 at a quantity of 50,000 units/year. One United States patent was allowed covering the heat pump technology, and two divisional applications and three Continuation-in-Park Applications were filed with the U.S.P.T.O. Corresponding patent coverage was applied for in Canada, the EEC, Australia, and Japan. Testing of the prototype heat pump is continuing, as are life tests of multiple pump concepts amd long-term dynamic corrosion tests. Continued development and commercialization of gas absorption heat pumps based on the technology are recommended.

  13. Effect of densifying the GNSS GBAS network on monitoring the troposphere zenith total delay and precipitable water vapour content during severe weather events

    NASA Astrophysics Data System (ADS)

    Kapłon, Jan; Stankunavicius, Gintautas

    2016-04-01

    The dense ground based augmentation networks can provide the important information for monitoring the state of neutral atmosphere. The GNSS&METEO research group at Wroclaw University of Environmental and Life Sciences (WUELS) is operating the self-developed near real-time service estimating the troposphere parameters from GNSS data for the area of Poland. The service is operational since December 2012 and it's results calculated from ASG-EUPOS GBAS network (120 stations) data are supporting the EGVAP (http://egvap.dmi.dk) project. At first the zenith troposphere delays (ZTD) were calculated in hourly intervals, but since September 2015 the service was upgraded to include SmartNet GBAS network (Leica Geosystems Polska - 150 stations). The upgrade included as well: increasing the result interval to 30 minutes, upgrade from Bernese GPS Software v. 5.0 to Bernese GNSS Software v. 5.2 and estimation of the ZTD and it's horizontal gradients. Processing includes nowadays 270 stations. The densification of network from 70 km of mean distance between stations to 40 km created the opportunity to investigate on it's impact on resolution of estimated ZTD and integrated water vapour content (IWV) fields during the weather events of high intensity. Increase in density of ZTD measurements allows to define better the meso-scale features within different synoptic systems (e.g. frontal waves, meso-scale convective systems, squall lines etc). These meso-scale structures, as a rule are short living but fast developing and hardly predictable by numerical models. Even so, such limited size systems can produce very hazardous phenomena - like widespread squalls and thunderstorms, tornadoes, heavy rains, snowfalls, hail etc. because of prevalence of Cb clouds with high concentration of IWV. Study deals with two meteorological events: 2015-09-01 with the devastating squalls and rainfall bringing 2M Euro loss of property in northern Poland and 2015-10-12 with the very active front bringing

  14. Calibration of the Purple Crow Lidar vibrational Raman water-vapour mixing ratio and temperature measurements

    NASA Astrophysics Data System (ADS)

    Argall, P. S.; Sica, R. J.; Bryant, C. R.; Algara-Siller, M.; Schijns, H.

    2007-02-01

    Purple Crow Lidar (PCL) measurements of the vibrational Raman-shifted backscatter from water vapour and nitrogen molecules allows height profiles of the water-vapour mixing ratio to be measured from 500 m up into the lower stratosphere. In addition, the Raman nitrogen measurements allow the determination of temperature profiles from about 10 to 40 km altitude. However, external calibration of these measurements is necessary to compensate for instrumental effects, uncertainties in our knowledge of the relevant molecular cross sections, and atmospheric transmission. A comparison of the PCL-derived water-vapour concentration and temperature profiles with routine radiosonde measurements from Detroit and Buffalo on 37 and 141 nights, respectively, was undertaken to provide this calibration. The calibration is then applied to the measurements and monthly mean-temperature and water-vapour profiles are determined.

  15. 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

    2016-06-01

    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). PMID:27159922

  16. 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).

  17. 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

  18. Classical two-split interference effects in double photoionization of molecular hydrogen at high energies

    SciTech Connect

    Horner, Daniel A; Miyabe, S; Rescigno, T N; Mccurdy, C W; Morales, F; Martin, F

    2009-01-01

    The authors report a thorough theoretical study of one photon double ionization of H{sub 2}. They suggest that interference effects reported in one photon ionization will be reproducible in the case of double ionization when one of the photons carriers most of the available energy and the other electron is not observed. These calculations reproduce recent double photoionization experiments of H{sub 2}.

  19. Molten Salt Promoting Effect in Double Salt CO2 Absorbents

    SciTech Connect

    Zhang, Keling; Li, Xiaohong S.; Chen, Haobo; Singh, Prabhakar; King, David L.

    2016-01-01

    The purpose of this paper is to elaborate on the concept of molten salts as catalysts for CO2 absorption by MgO, and extend these observations to the MgO-containing double salt oxides. We will show that the phenomena involved with CO2 absorption by MgO and MgO-based double salts are similar and general, but with some important differences. This paper focuses on the following key concepts: i) identification of conditions that favor or disfavor participation of isolated MgO during double salt absorption, and investigation of methods to increase the absorption capacity of double salt systems by including MgO participation; ii) examination of the relationship between CO2 uptake and melting point of the promoter salt, leading to the recognition of the role of pre-melting (surface melting) in these systems; and iii) extension of the reaction pathway model developed for the MgO-NaNO3 system to the double salt systems. This information advances our understanding of MgO-based CO2 absorption systems for application with pre-combustion gas streams.

  20. A liquid crystalline chirality balance for vapours

    NASA Astrophysics Data System (ADS)

    Ohzono, Takuya; Yamamoto, Takahiro; Fukuda, Jun-Ichi

    2014-04-01

    Chiral discrimination of vapours plays an important role in olfactory perception of biological systems and its realization by artificial sensors has been an intriguing challenge. Here, we report a simple method that tangibly visualizes the chirality of a diverse variety of molecules dissolved from vapours with high sensitivity, by making use of a structural change in a periodic microstructure of a nematic liquid crystal confined in open microchannels. This microstructure is accompanied by a topological line defect of a zigzag form with equal lengths of ‘zig’ and ‘zag.’ We find that a tiny amount of vapour of chiral molecules injected onto the liquid crystal induces the imbalance of ‘zig’ and ‘zag’ depending on its enantiomeric excess within a few seconds. Our liquid-crystal-based ‘chirality balance’ offers a simple, quick and versatile chirality-sensing/-screening method for gas-phase analysis (for example, for odours, environmental chemicals or drugs).

  1. Electroluminescence of double-doped diamond thin films

    NASA Astrophysics Data System (ADS)

    Zhang, Shi; Wang, Xiao-Ping; Wang, Li-Jun; Zhu, Yu-Zhuan; Mei, Cui-Yu; Liu, Xin-Xin; Li, Huai-Hui; Gu, Ying-Zhan

    2010-09-01

    A new electroluminescence device is fabricated by microwave plasma chemical vapour deposition system and electron beam vapour deposition system. It is comprised of highly doped silicon/diamond/boron/nitrogen-doped diamond/indium tin oxide thin films. Effects of process parameters on morphologies and structures of the thin films are detected and analysed by scanning electron microscopy, Raman spectrometer and x-ray photoelectron spectrometer. A direct-current (DC) power supply is used to drive the electroluminescence device. The blue light emission with a luminance of 1.2 cd-m-2 is observed from this double-doped diamond thin film electroluminescence device at an applied voltage of 105 V.

  2. Double Allee effects and extinction in the island fox.

    PubMed

    Angulo, Elena; Roemer, Gary W; Berec, Ludek; Gascoigne, Joanna; Courchamp, Franck

    2007-08-01

    An Allee effect (AE) occurs in populations when individuals suffer a decrease in fitness at low densities. If a fitness component is reduced (component AE), per capita population growth rates may decline as a consequence (demographic AE) and extinction risk is increased. The island fox (Urocyon littoralis) is endemic to six of the eight California Channel Islands. Population crashes have coincided with an increase in predation by Golden Eagles (Aquila chrysaetos). We propose that AEs could render fox populations more sensitive and may be a likely explanation for their sharp decline. We analyzed demographic data collected between 1988 and 2000 to test whether fox density (1) influences survival and reproductive rates; (2) interacts with eagle presence and affects fox fitness parameters; and (3) influences per capita fox population trends. A double component AE simultaneously influenced survival (of adults and pups) and proportion of breeding adult females. The adult survival AE was driven by predation by eagles. These component AEs led to a demographic AE. Multiple-component AEs, a predation-driven AE, and the simultaneous occurrence of both component and demographic AEs in a mammal are all previously unreported processes. Populations below 7 foxes/km(2) could have suboptimal population growth rates due to the demographic AE, and AEs may have contributed to the dramatic declines in three fox populations. Because fox densities in critically endangered populations are well below this level, removing Golden Eagles appears necessary to prevent a predation-driven AE. Conservationists should also be aware of AEs when planning the release of captive foxes. More generally, our findings highlight the danger of overlooking AEs in the conservation of populations of rare or threatened species.

  3. Double Allee effects and extinction in the island fox.

    PubMed

    Angulo, Elena; Roemer, Gary W; Berec, Ludek; Gascoigne, Joanna; Courchamp, Franck

    2007-08-01

    An Allee effect (AE) occurs in populations when individuals suffer a decrease in fitness at low densities. If a fitness component is reduced (component AE), per capita population growth rates may decline as a consequence (demographic AE) and extinction risk is increased. The island fox (Urocyon littoralis) is endemic to six of the eight California Channel Islands. Population crashes have coincided with an increase in predation by Golden Eagles (Aquila chrysaetos). We propose that AEs could render fox populations more sensitive and may be a likely explanation for their sharp decline. We analyzed demographic data collected between 1988 and 2000 to test whether fox density (1) influences survival and reproductive rates; (2) interacts with eagle presence and affects fox fitness parameters; and (3) influences per capita fox population trends. A double component AE simultaneously influenced survival (of adults and pups) and proportion of breeding adult females. The adult survival AE was driven by predation by eagles. These component AEs led to a demographic AE. Multiple-component AEs, a predation-driven AE, and the simultaneous occurrence of both component and demographic AEs in a mammal are all previously unreported processes. Populations below 7 foxes/km(2) could have suboptimal population growth rates due to the demographic AE, and AEs may have contributed to the dramatic declines in three fox populations. Because fox densities in critically endangered populations are well below this level, removing Golden Eagles appears necessary to prevent a predation-driven AE. Conservationists should also be aware of AEs when planning the release of captive foxes. More generally, our findings highlight the danger of overlooking AEs in the conservation of populations of rare or threatened species. PMID:17650257

  4. Neutronic effects on tungsten-186 double neutron capture

    NASA Astrophysics Data System (ADS)

    Garland, Marc Alan

    Rhenium-188, a daughter product of tungsten-188, is an isotope of great interest in therapeutic nuclear medicine, being used in dozens of laboratory and clinical investigations worldwide. Applications include various cancer therapy strategies, treatment of rheumatoid arthritis, prevention of restenosis following coronary artery angioplasty, and palliation of bone pain associated with cancer metastases. With its half-life of 17 hours, 2.12 MeV (maximum) beta-particle emission, chemical similarity to technetium-99m (the most widely used diagnostic radioisotope), and its availability in a convenient tungsten-188/rhenium-188 generator system, rhenium-188 is a superb candidate for a broad range of applications. Production of 188W is typically via double neutron capture by 186W in a high flux nuclear reactor, predominantly the High Flux Isotope Reactor at the Oak Ridge National Laboratory in Tennessee. Experience at HFIR has shown that production yields (measured in Ci of 188W produced per g of 186W target) decrease considerably as target size increases. While the phenomenon of neutron resonance self-shielding would be expected to produce such an effect, temperature effects on neutron flux distribution and neutron capture rates may also be involved. Experimental investigations of these phenomena have not been previously performed. The work presented in this thesis evaluates the factors that contribute to the decrease in 188W yield from both theoretical and experimental standpoints. Neutron self-shielding and temperature effects were characterized to develop a strategy for target design that would optimize production yield, an important factor in minimizing health care costs. It was determined that decrease in yield due to neutron self-shielding can be attributed to depletion of epithermal neutrons at resonant energies, most significantly within the initial 0.4 mm depth of the target. The results from these studies further show that 188W yield in the interior of the

  5. Modelling vapour transport in Surtseyan bombs

    NASA Astrophysics Data System (ADS)

    McGuinness, Mark J.; Greenbank, Emma; Schipper, C. Ian

    2016-05-01

    We address questions that arise if a slurry containing liquid water is enclosed in a ball of hot viscous vesicular magma ejected as a bomb in the context of a Surtseyan eruption. We derive a mathematical model for transient changes in temperature and pressure due to flashing of liquid water to vapour inside the bomb. The magnitude of the transient pressure changes that are typically generated are calculated together with their dependence on material properties. A single criterion to determine whether the bomb will fragment as a result of the pressure changes is derived. Timescales for ejection of water vapour from a bomb that remains intact are also revealed.

  6. Nonsequential double ionization as a completely classical photoelectric effect.

    PubMed

    Ho, Phay J; Panfili, R; Haan, S L; Eberly, J H

    2005-03-11

    We introduce a unified and simplified theory of atomic double ionization. Our results show that at high laser intensities (I>/=10(14) W/cm(2)) purely classical correlation is strong enough to account for all of the main features observed in experiments to date.

  7. A Cross Racial Study of Double Consciousness Effects

    ERIC Educational Resources Information Center

    Sussewell, Deborah Ridley

    The double consciousness model represents Black self-concept as being comprised of three primary cognitive structures: the "I," the "me," and the "we" self-referents. A study was conducted to examine three assumptions pertaining to the "we" self-referent: (1) that it reflects attitudes and behaviors developed because of Black Americans' African…

  8. Relativistic effects on giant resonances in electron-impact double ionization

    SciTech Connect

    Pindzola, M.S.

    1987-06-01

    The electron-impact double-ionization cross section for Fr/sup +/ is calculated in the distorted-wave Born approximation. A giant resonance in the 5d subshell ionization-autoionization contribution to the cross section is found to be quite sensitive to changes in the double-well potential caused by relativistic effects on bound-state wave functions.

  9. Singling out the double effect - sexual health advice and contraception are ethically distinct

    PubMed Central

    Bow, Steven

    2015-01-01

    Abstract This article is a response to an article previously published in LJPC, which employed the doctrine of double effect to explain the Gillick judgement and exculpate health care workers who provide contraceptives and sexual health advice to under-16s. In this analysis, the two acts: provision of contraceptives and provision of sexual health advice are examined separately against the four criteria of the doctrine of double effect. In conclusion, whilst sexual health advice provision fits into the doctrine reasonably well, in the case of contraceptive provision, the validity of the doctrine of double effect is more doubtful. PMID:26550037

  10. Saturated Vapour Pressure and Refrigeration - Part I

    ERIC Educational Resources Information Center

    Bunker, C. A.

    1973-01-01

    The first part of a two-part article describes an experimental approach that can be used in teaching the concept of saturated vapour pressure. This leads to a discussion of refrigeration cycles in the second part of the article. (JR)

  11. Effects of autoionizing states on two-photon double ionization of the H2 molecule

    NASA Astrophysics Data System (ADS)

    Guan, Xiaoxu; Bartschat, Klaus; Koesterke, Lars; Schneider, Barry I.

    2014-04-01

    We report angle-resolved and angle-integrated cross sections for two-photon double-ionization of H by a strong laser pulse. The effect of doubly excited states on the predicted cross sections is addressed.

  12. The effect of stabilizer on the mechanical response of double-emulsion-templated polymersomes.

    PubMed

    Jang, Woo-Sik; Park, Seung Chul; Kim, Miju; Doh, Junsang; Lee, Daeyeon; Hammer, Daniel A

    2015-02-01

    Recent studies have shown that polymersomes templated by microfluidic double-emulsion possess several advantages such as high monodispersity and encapsulation efficiency compared with those generated based on thin-film rehydration and electroformation. Stabilizers, including bovine serum albumin (BSA) and polyvinyl alcohol (PVA), have been used to enhance the formation and stability of double emulsions that are used as templates for the generation of polymersomes. In this work, the effect of stabilizers on the mechanical response of double-emulsion-templated polymersomes using micropipette aspiration is investigated. It is demonstrated that the existence of stabilizers results in the inelastic response in poly-mersomes in the early stage of solvent removal. However, aged polymersomes that have little residual solvent show elastic behavior. Polymersomes prepared from PVA-stabilized double emulsions have noticeably lower area expansion moduli than polymersomes prepared from stabilizer-free and BSA-stabilized double emulsions, suggesting that PVA is incorporated in the bilayer membrane of polymersomes.

  13. The sEDA(=) and pEDA(=) descriptors of the double bonded substituent effect.

    PubMed

    Mazurek, Andrzej; Dobrowolski, Jan Cz

    2013-05-14

    New descriptors of the double bonded substituent effect, sEDA(=) and pEDA(=), were constructed based on quantum chemical calculations and NBO methodology. They show to what extent the σ and π electrons are donated to or withdrawn from the substituted system by a double bonded substituent. The new descriptors differ from descriptors of the classical substituent effect for which the pz orbital of the ipso carbon atom is engaged in the π-electron system of the two neighboring atoms in the ring. For double bonded substituents, the pz orbital participates in double bond formation with only one external atom. Moreover, the external double bond forces localization of the double bond system of the ring, significantly changing the core molecule. We demonstrated good agreement between our descriptors and the Weinhold and Landis' "natural σ and π-electronegativities": so far only descriptors allowing for evaluation of the substitution effect by a double bonded atom. The equivalency between descriptors constructed for 5- and 6-membered model structures as well as linear dependence/independence of the constructed parameters was discussed. Some interrelations between sEDA(=) and pEDA(=) and the other descriptors of (hetero)cyclic systems such as aromaticity and electron density in the ring and bond critical points were also examined.

  14. Effective decomposition algorithm for self-aligned double patterning lithography

    NASA Astrophysics Data System (ADS)

    Zhang, Hongbo; Du, Yuelin; Wong, Martin D. F.; Topaloglu, Rasit; Conley, Will

    2011-04-01

    Self-aligned double patterning (SADP) lithography is a novel lithography technology that has the intrinsic capability to reduce the overlay in the double patterning lithography (DPL). Although SADP is the critical technology to solve the lithography difficulties in sub-32nm 2D design, the questions - how to decompose a layout with reasonable overlay and how to perform a decomposability check - are still two open problems with no published work. In this paper, by formulating the problem into a SAT formation, we can answer the above two questions optimally. This is the first published paper with detailed algorithm to perform the SADP decomposition. In a layout, we can efficiently check whether a layout is decomposable. For a decomposable layout, our algorithm guarantees to find a decomposition solution with reasonable overlay reduction requirement. With little changes on the clauses in the SAT formula, we can address the decomposition problem for both the positive tone process and the negative tone process. Experimental results validate our method, and decomposition results for Nangate Open Cell Library and larger test cases are also provided with competitive run times.

  15. Water Vapour Abundance and Distribution in the Lower Venusian Atmosphere

    NASA Astrophysics Data System (ADS)

    Chamberlain, S.; Bailey, J.

    2012-04-01

    We present ground-based observations and modelling studies of water vapour abundance and distribution in the Venusian lower atmosphere through analysis of absorption band depths within the 1.18 μm window. The lower atmosphere of Venus is difficult to study by both in situ and remote instruments. This is due to the planet wide cloud cover that obscures visual wavelengths and surface pressures approaching 100 times that of the Earth. In 1984 ground based observations resulted in the discovery of atmospheric windows on the Venusian nightside (Allen and Crawford, 1984). Here, near infrared radiation originating at the surface and lower atmosphere, pass relatively unimpeded through the Venus clouds. This discovery enabled remote studies of the Venusian subcloud region. Determining the abundance and distribution of water vapour is key to understanding the development, maintenance and links between major radiative and dynamical features of the Venus atmosphere. Water vapour in the lower atmosphere plays an important role in heat transfer and is pertinent to the runaway greenhouse effect and dynamical superrotation observed on Venus. Detailed studies of water vapour abundance and distribution throughout the lower atmosphere of Venus are therefore needed in order to develop accurate chemical, radiative and dynamical models. Ground-based spatially resolved near infrared spectroscopic observations of the Venusian nightside have been obtained from Siding Spring Observatory at each inferior conjunction since 2002. Observations have been made using the IRIS2 instrument on the Anglo-Australian Telescope and CASPIR on the 2.3m ANU telescope. The model VSTAR (Bailey and Kedziora-Chudczer 2012) is used to simulate the observed Venus spectra as seen through the Earth's atmosphere and best fit water vapour abundances are found for approximately 300 locations across the Venus nightside disk. Recent improvements in ground-based near-infrared instruments allow a substantial improvement

  16. Textile damage caused by vapour cloud explosions.

    PubMed

    Was-Gubala, J; Krauss, W

    2004-01-01

    The aim of the project was to investigate the damage to garments caused by particular vapour cloud explosions. The authors would like to be able to provide investigators with specific information on how to link clothes to a specific type of crime: a particular case study was the inspiration for the examinations. Experiments were carried out in the fire reconstruction chamber of the laboratory using a selection of 26 clothes and 15 household garments differing in colour, fibre composition and textile construction.

  17. The effect of unemployment on household composition and doubling up.

    PubMed

    Wiemers, Emily E

    2014-12-01

    "Doubling up" (sharing living arrangements) with family and friends is one way in which individuals and families can cope with job loss, but relatively little research has examined the extent to which people use coresidence to weather a spell of unemployment. This project uses data from the Survey of Income and Program Participation (SIPP) to provide evidence on the relationship between household composition and unemployment across working ages, focusing on differences in behavior by educational attainment. Using the SIPP panels, I find that individuals who become unemployed are three times more likely to move in with other people. Moving into shared living arrangements in response to unemployment is not evenly spread across the distribution of educational attainment: it is most prevalent among individuals with less than a high school diploma and those with at least some college.

  18. The Effect of Unemployment on Household Composition and Doubling Up

    PubMed Central

    Wiemers, Emily E.

    2015-01-01

    Doubling up” (sharing living arrangements) with family and friends is one way in which individuals and families can cope with job loss, but relatively little research has examined the extent to which people use coresidence to weather a spell of unemployment. This project uses data from the Survey of Income and Program Participation (SIPP) to provide evidence on the relationship between household composition and unemployment across working ages, focusing on differences in behavior by educational attainment. Using the SIPP panels, I find that individuals who become unemployed are three times more likely to move in with other people. Moving into shared living arrangements in response to unemployment is not evenly spread across the distribution of educational attainment: it is most prevalent among individuals with the less than a high school diploma and those with at least some college. PMID:25421522

  19. Double binding energy differences: Mean-field or pairing effect?

    NASA Astrophysics Data System (ADS)

    Qi, Chong

    2012-10-01

    In this Letter we present a systematic analysis on the average interaction between the last protons and neutrons in atomic nuclei, which can be extracted from the double differences of nuclear binding energies. The empirical average proton-neutron interaction Vpn thus derived from experimental data can be described in a very simple form as the interplay of the nuclear mean field and the pairing interaction. It is found that the smooth behavior as well as the local fluctuations of the Vpn in even-even nuclei with N ≠ Z are dominated by the contribution from the proton-neutron monopole interactions. A strong additional contribution from the isoscalar monopole interaction and isovector proton-neutron pairing interaction is seen in the Vpn for even-even N = Z nuclei and for the adjacent odd-A nuclei with one neutron or proton being subtracted.

  20. Double parton effects for jets with large rapidity separation

    SciTech Connect

    Szczurek, Antoni; Cisek, Anna; Maciuła, Rafal

    2015-04-10

    We discuss production of four jets pp → jjjjX with at least two jets with large rapidity separation in proton-proton collisions at the LHC through the mechanism of double-parton scattering (DPS). The cross section is calculated in a factorizaed approximation. Each hard subprocess is calculated in LO collinear approximation. The LO pQCD calculations are shown to give a reasonably good descritption of CMS and ATLAS data on inclusive jet production. It is shown that relative contribution of DPS is growing with increasing rapidity distance between the most remote jets, center-of-mass energy and with decreasing (mini)jet transverse momenta. We show also result for angular azimuthal dijet correlations calculated in the framework of k{sub t} -factorization approximation.

  1. The effect of unemployment on household composition and doubling up.

    PubMed

    Wiemers, Emily E

    2014-12-01

    "Doubling up" (sharing living arrangements) with family and friends is one way in which individuals and families can cope with job loss, but relatively little research has examined the extent to which people use coresidence to weather a spell of unemployment. This project uses data from the Survey of Income and Program Participation (SIPP) to provide evidence on the relationship between household composition and unemployment across working ages, focusing on differences in behavior by educational attainment. Using the SIPP panels, I find that individuals who become unemployed are three times more likely to move in with other people. Moving into shared living arrangements in response to unemployment is not evenly spread across the distribution of educational attainment: it is most prevalent among individuals with less than a high school diploma and those with at least some college. PMID:25421522

  2. A liquid crystalline chirality balance for vapours

    PubMed Central

    Ohzono, Takuya; Yamamoto, Takahiro; Fukuda, Jun-ichi

    2014-01-01

    Chiral discrimination of vapours plays an important role in olfactory perception of biological systems and its realization by artificial sensors has been an intriguing challenge. Here, we report a simple method that tangibly visualizes the chirality of a diverse variety of molecules dissolved from vapours with high sensitivity, by making use of a structural change in a periodic microstructure of a nematic liquid crystal confined in open microchannels. This microstructure is accompanied by a topological line defect of a zigzag form with equal lengths of ‘zig’ and ‘zag.’ We find that a tiny amount of vapour of chiral molecules injected onto the liquid crystal induces the imbalance of ‘zig’ and ‘zag’ depending on its enantiomeric excess within a few seconds. Our liquid-crystal-based ‘chirality balance’ offers a simple, quick and versatile chirality-sensing/-screening method for gas-phase analysis (for example, for odours, environmental chemicals or drugs). PMID:24781531

  3. Deformation effect simulation and optimization for double front axle steering mechanism

    NASA Astrophysics Data System (ADS)

    Wu, Jungang; Zhang, Siqin; Yang, Qinglong

    2013-03-01

    This paper research on tire wear problem of heavy vehicles with Double Front Axle Steering Mechanism from the flexible effect of Steering Mechanism, and proposes a structural optimization method which use both traditional static structural theory and dynamic structure theory - Equivalent Static Load (ESL) method to optimize key parts. The good simulated and test results show this method has high engineering practice and reference value for tire wear problem of Double Front Axle Steering Mechanism design.

  4. 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.

  5. Effect of carbon entrapped in Co-Al double oxides on structural restacking and electrochemical performances

    NASA Astrophysics Data System (ADS)

    Su, Ling-Hao; Zhang, Xiao-Gang

    Co-Al layered double hydroxides (LDH) were synthesized from nitrates and sodium benzoate by direct coprecipitation, and heated at 600 °C for 3 h in argon gas flow to obtain Co-Al double oxides. The effect of carbon, created during the pyrolysis of benzoate and inserted in resulting double oxides, on structural reconstruction was investigated by X-ray diffraction, scanning electron microscope, Raman spectroscopy, and infrared spectroscopy techniques. It is horizontal arrangement rather than vertical dilayer orientation in the interlayer spacing that was adopted by benzoate. An abnormal phenomenon was found that when immersed in aqueous 6 M KOH solution in air, the double oxides restacked to Co-Al layered double hydroxides with more regular crystal than before. The reason is believed that carbon was confined in the matrix of resulting double oxides, which prevented further collapse of the layered structure. Cyclic voltammetries (CV) and constant current charge/discharge measurements reveal that the restacked Co-Al layered double hydroxide has good long-life capacitive performance with a capacitance up to 145 F g -1 even at a large current of 2 A g -1. In addition, two clear slopes in chronoampermetric test demonstrated two different diffusion coefficients, explaining the slope of about 118.4 mV in the plot of formal potential E f versus pOH.

  6. Analysis of characteristics of a diode-pumped rubidium vapour laser using a kinetic algorithm

    NASA Astrophysics Data System (ADS)

    Cai, He; Wang, You; Zhang, Wei; Xue, Liangping; Wang, Hongyuan; Han, Juhong; An, Guofei; Jiang, Zhigang; Gao, Ming; Zhou, Jie; Liao, Zhiye

    2016-08-01

    We consider diode-pumped alkali vapour lasers (DPALs), which make it possible to achieve a high output power. Characteristics of such DPALs strongly depend on the physical properties of buffer gases and on structural parameters of a vapour cell. Special attention is paid to a diode-pumped rubidium vapour laser (DPRVL): We have investigated the effect of different conditions on its characteristics. The results show that the linewidth of the D2 line of a DPRVL and the fine-structure mixing rate between two excited energy levels, which are two crucial factors in implementing a high-power DPRVL, increase with the pressure of buffer gases and the temperature of the vapour cell. It is demonstrated that the population ratio of two excited energy levels is close to that corresponding to a thermal equilibrium as the pressure of buffer gases and the temperature of the vapour cell become higher. We have found that the optimal values of the methane pressure, the cell temperature and the cell length can be determined through a kinetic analysis. The conclusions can be valuable for designing configurations of an end-pumped DPAL.

  7. Metal Vapour Lasers: Physics, Engineering and Applications

    NASA Astrophysics Data System (ADS)

    Little, Christopher E.

    1999-03-01

    Metal Vapour Lasers Christopher E. Little University of St Andrews, St Andrews, Scotland Since the first successful demonstration of a metal vapour laser (MVL) in 1962, this class of laser has become widely used in a broad range of fields including precision materials processing, isotope separation and medicine. The MVLs that are used today have a range of impressive characteristics that are not readily available using other technologies. In particular, the combination of high average output powers, pulse recurrence frequencies and beam quality available from green/yellow Cu vapour lasers (CVLs) and Cu bromide lasers, coupled with the high-quality, multiwatt ultraviolet (265-289 nm) radiation that can be produced using simple nonlinear optical techniques, means that Cu lasers will continue to be important for many years. Metal Vapour Lasers covers all the most commercially important and scientifically interesting pulsed and continuous wave (CW) gas-discharge MVLs, and includes device histories, operating characteristics, engineering, kinetics, commercial exploitation and applications. Short descriptions of gas discharges and excitation techniques make this volume self-consistent. A comprehensive bibliography is also provided. The greater part of this book is devoted to CVLs and their variants, including new sealed-off, high-power 'kinetically enhanced' CVLs and Cu bromide lasers. However, many other self-terminating MVLs are also discussed, including the red AuVL, green/infrared MnVL and infrared BaVL. Pulsed, high-gain, high average power lasers in the UV/violet (373.7, 430.5 nm) spectral regions are represented by Sr¯+ and Ca¯+ discharge-afterglow recombination lasers. The most commercially successful of the MVLs - the CW, UV/blue cataphoretic He-Cd¯+ ion laser - is described. Hollow cathode lasers are represented in two guises: 'white light' (blue/green/red) He-Cd¯+ ion lasers and UV/infrared Ne/He-Cu¯+ ion lasers. This unique volume is an

  8. The effect of carbon precursors (methane, benzene and camphor) on the quality of carbon nanotubes synthesised by the chemical vapour decomposition

    NASA Astrophysics Data System (ADS)

    Liu, Wei-Wen; Aziz, Azizan; Chai, Siang-Piao; Mohamed, Abdul Rahman; Tye, Ching-Thian

    2011-06-01

    The effect of carbon precursors on carbon nanotube (CNT) formation was studied. The catalyst used was Fe 3O 4/MgO without prior reduction by hydrogen. Methane, benzene and camphor were used to produce CNTs at 600, 700, 800, 900 and 1000 °C. The results show that the types of carbon precursors greatly affect the quality of CNTs produced. The CNTs obtained from the decomposition of methane had the lowest intensity of D band to G band ratio ( ID/ IG) compared to the ID/ IG ratios of CNTs produced using benzene and camphor at 900 and 1000 °C, respectively. This low ID/ IG ratio is due to the difference in the molecule structures between methane, benzene and camphor, which resulted in different CNT growth mechanism. Raman analysis showed that single-walled carbon nanotubes of high quality were formed at 900 °C using methane as carbon precursor.

  9. Variability of water vapour in the Arctic stratosphere

    NASA Astrophysics Data System (ADS)

    Thölix, L.; Backman, L.; Kivi, R.; Karpechko, A.

    2015-08-01

    This study evaluates the stratospheric water vapour distribution and variability in the Arctic. A FinROSE chemistry climate model simulation covering years 1990-2013 is compared to observations (satellite and frostpoint hygrometer soundings) and the sources of stratospheric water vapour are studied. According to observations and the simulations the water vapour concentration in the Arctic stratosphere started to increase after year 2006, but around 2011 the concentration started to decrease. Model calculations suggest that the increase in water vapour during 2006-2011 (at 56 hPa) is mostly explained by transport related processes, while the photochemically produced water vapour plays a relatively smaller role. The water vapour trend in the stratosphere may have contributed to increased ICE PSC occurrence. The increase of water vapour in the precense of the low winter temperatures in the Arctic stratosphere led to more frequent occurrence of ICE PSCs in the Arctic vortex. The polar vortex was unusually cold in early 2010 and allowed large scale formation of the polar stratospheric clouds. The cold pool in the stratosphere over the Northern polar latitudes was large and stable and a large scale persistent dehydration was observed. Polar stratospheric ice clouds and dehydration were observed at Sodankylä with accurate water vapour soundings in January and February 2010 during the LAPBIAT atmospheric sounding campaign. The observed changes in water vapour were reproduced by the model. Both the observed and simulated decrease of the water vapour in the dehydration layer was up to 1.5 ppm.

  10. Tomographic retrieval of water vapour and temperature around polar mesospheric clouds using Odin-SMR

    NASA Astrophysics Data System (ADS)

    Christensen, O. M.; Eriksson, P.; Urban, J.; Murtagh, D.; Hultgren, K.; Gumbel, J.

    2014-11-01

    , effects of PMCs on the water vapour distribution are clearly seen. Areas depleted of water vapour are found above layers with PMC, while regions of enhanced water vapour due to ice particle sedimentation are primarily placed between and under the clouds.

  11. Tomographic retrieval of water vapour and temperature around polar mesospheric clouds using Odin-SMR

    NASA Astrophysics Data System (ADS)

    Christensen, O. M.; Eriksson, P.; Urban, J.; Murtagh, D.; Hultgren, K.; Gumbel, J.

    2015-05-01

    A special observation mode of the Odin satellite provides the first simultaneous measurements of water vapour, temperature and polar mesospheric cloud (PMC) brightness over a large geographical area while still resolving both horizontal and vertical structures in the clouds and background atmosphere. The observation mode was activated during June, July and August of 2010 and 2011, and for latitudes between 50 and 82° N. This paper focuses on the water vapour and temperature measurements carried out with Odin's sub-millimetre radiometer (SMR). The tomographic retrieval approach used provides water vapour and temperature between 75 and 90 km with a vertical resolution of about 2.5 km and a horizontal resolution of about 200 km. The precision of the measurements is estimated to 0.2 ppmv for water vapour and 2 K for temperature. Due to limited information about the pressure at the measured altitudes, the results have large uncertainties (> 3 ppmv) in the retrieved water vapour. These errors, however, influence mainly the mean atmosphere retrieved for each orbit, and variations around this mean are still reliably captured by the measurements. SMR measurements are performed using two different mixer chains, denoted as frequency mode 19 and 13. Systematic differences between the two frontends have been noted. A first comparison with the Solar Occultation For Ice Experiment instrument (SOFIE) on-board the Aeronomy of Ice in the Mesosphere (AIM) satellite and the Fourier Transform Spectrometer of the Atmospheric Chemistry Experiment (ACE-FTS) on-board SCISAT indicates that the measurements using the frequency mode 19 have a significant low bias in both temperature (> 15 K) and water vapour (> 0.5 ppmv), while the measurements using frequency mode 13 agree with the other instruments considering estimated errors. PMC brightness data is provided by OSIRIS, Odin's other sensor. Combined SMR and OSIRIS data for some example orbits is considered. For these orbits, effects of

  12. [Qualitative Determination of Organic Vapour Using Violet and Visible Spectrum].

    PubMed

    Jiang, Bo; Hu, Wen-zhong; Liu, Chang-jian; Zheng, Wei; Qi, Xiao-hui; Jiang, Ai-li; Wang, Yan-ying

    2015-12-01

    Vapours of organic matters were determined qualitatively employed with ultraviolet-visible absorption spectroscopy. Vapours of organic matters were detected using ultraviolet-visible spectrophotometer employing polyethylene film as medium, the ultraviolet and visible absorption spectra of vegetable oil vapours of soybean oil, sunflower seed oil, peanut oil, rapeseed oil, sesame oil, cotton seed oil, tung tree seed oil, and organic compound vapours of acetone, ethyl acetate, 95% ethanol, glacial acetic acid were obtained. Experimental results showed that spectra of the vegetable oil vapour and the organic compound vapour could be obtained commendably, since ultra violet and visible spectrum of polyethylene film could be deducted by spectrograph zero setting. Different kinds of vegetable oils could been distinguished commendably in the spectra since the λ(max), λ(min), number of absorption peak, position, inflection point in the ultra violet and visible spectra obtained from the vapours of the vegetable oils were all inconsistent, and the vapours of organic compounds were also determined perfectly. The method had a good reproducibility, the ultraviolet and visible absorption spectra of the vapours of sunflower seed oil in 10 times determination were absolutely the same. The experimental result indicated that polyethylene film as a kind of medium could be used for qualitative analysis of ultraviolet and visible absorption spectroscopy. The method for determination of the vapours of the vegetable oils and organic compounds had the peculiarities of fast speed analysis, well reproducibility, accuracy and reliability and low cost, and so on. Ultraviolet and visible absorption spectrum of organic vapour could provide feature information of material vapour and structural information of organic compound, and provide a novel test method for identifying vapour of compound and organic matter.

  13. [Qualitative Determination of Organic Vapour Using Violet and Visible Spectrum].

    PubMed

    Jiang, Bo; Hu, Wen-zhong; Liu, Chang-jian; Zheng, Wei; Qi, Xiao-hui; Jiang, Ai-li; Wang, Yan-ying

    2015-12-01

    Vapours of organic matters were determined qualitatively employed with ultraviolet-visible absorption spectroscopy. Vapours of organic matters were detected using ultraviolet-visible spectrophotometer employing polyethylene film as medium, the ultraviolet and visible absorption spectra of vegetable oil vapours of soybean oil, sunflower seed oil, peanut oil, rapeseed oil, sesame oil, cotton seed oil, tung tree seed oil, and organic compound vapours of acetone, ethyl acetate, 95% ethanol, glacial acetic acid were obtained. Experimental results showed that spectra of the vegetable oil vapour and the organic compound vapour could be obtained commendably, since ultra violet and visible spectrum of polyethylene film could be deducted by spectrograph zero setting. Different kinds of vegetable oils could been distinguished commendably in the spectra since the λ(max), λ(min), number of absorption peak, position, inflection point in the ultra violet and visible spectra obtained from the vapours of the vegetable oils were all inconsistent, and the vapours of organic compounds were also determined perfectly. The method had a good reproducibility, the ultraviolet and visible absorption spectra of the vapours of sunflower seed oil in 10 times determination were absolutely the same. The experimental result indicated that polyethylene film as a kind of medium could be used for qualitative analysis of ultraviolet and visible absorption spectroscopy. The method for determination of the vapours of the vegetable oils and organic compounds had the peculiarities of fast speed analysis, well reproducibility, accuracy and reliability and low cost, and so on. Ultraviolet and visible absorption spectrum of organic vapour could provide feature information of material vapour and structural information of organic compound, and provide a novel test method for identifying vapour of compound and organic matter. PMID:26964229

  14. Thermal effects of asymmetric electrolytes in electric double layer capacitors

    NASA Astrophysics Data System (ADS)

    d'Entremont, Anna L.; Pilon, Laurent

    2015-01-01

    This study presents a thermal model, derived from first principles, for electric double layer capacitors (EDLCs) with multiple ion species and/or asymmetric electrolytes. It accounts for both irreversible and reversible heat generation rates resulting from the transient electrodiffusion of ions within the electrolyte. Detailed numerical simulations of EDLCs with planar electrodes and binary and asymmetric electrolytes were performed under galvanostatic cycling. The irreversible Joule heating decreased with increasing valency and/or diffusion coefficient of either ion. The local reversible heat generation rate near a given electrode was determined by the properties of the counterion. It increased with increasing counterion valency and/or decreasing counterion diameter. As a result, the electrode with the counterion of smaller diameter and/or larger valency experienced significantly larger temperature oscillations during galvanostatic cycling than the opposite electrode. In general, EDLC electrolytes featuring ions with large valency and/or small diameter produce large capacitance but also large reversible heating. The present study suggests that EDLC electrolytes should feature large bulk ion concentrations and at least one ion with a large diffusion coefficient to minimize both irreversible and reversible heating.

  15. Crystal growth of HfS 2 by chemical vapour transport with halogen (Cl, Br, I)

    NASA Astrophysics Data System (ADS)

    Fiechter, S.; Eckert, K.

    1988-05-01

    Single crystals of HfS 2 have been prepared by chemical vapour transport (CVT) with halogen. Depending on the transporting agent added, exergonic or endergonic transport was observed. Employing 0.5 mg/cm 3 chlorine or bromine in evacuated and sealed quartz ampoules, exergonic transport occurs. In a temperature gradient from 850 to 870 K transparent reddish-orange crystal platelets of pseudohexagonal shape (10×10×0.05 mm3) were obtained. Endergonic transport, found with iodine as transporting agent, first starts at higher temperatures (1270-1220 K). A thermochemical study of the vapour phase composition revealed that gaseous HfHal 4 and HfHal 3 ( Hal = Cl, Br) are responsible for the exergonic transport observed. Because of the higher stability of HfS 2 against iodine, CVT first starts at elevated temperatures. In the vapour phase Hfl and Hfl 2 dominate and effect a reversal of the transport direction.

  16. Relation between ac Josephson effect and double-well Bose-Einstein-condensate oscillations

    SciTech Connect

    Radzihovsky, Leo; Gurarie, Victor

    2010-06-15

    In this article we comment on the relation between the ac Josephson effect and the coherent oscillations of a Bose-Einstein condensate confined to a double-well potential. The goal is to elucidate the extent to which the latter is a realization of the former. We detail the correspondence between the two oscillation frequencies, that emerges in the high occupation limit of the double-well potential. We show that in the latter thermodynamic limit the effective one-particle interwell coupling vanishes with the system size, leading to oscillation frequency that depends only on the interwell imbalance, consistent with the ac Josephson effect frequency.

  17. Relation between ac Josephson effect and double-well Bose-Einstein-condensate oscillations

    NASA Astrophysics Data System (ADS)

    Radzihovsky, Leo; Gurarie, Victor

    2010-06-01

    In this article we comment on the relation between the ac Josephson effect and the coherent oscillations of a Bose-Einstein condensate confined to a double-well potential. The goal is to elucidate the extent to which the latter is a realization of the former. We detail the correspondence between the two oscillation frequencies, that emerges in the high occupation limit of the double-well potential. We show that in the latter thermodynamic limit the effective one-particle interwell coupling vanishes with the system size, leading to oscillation frequency that depends only on the interwell imbalance, consistent with the ac Josephson effect frequency.

  18. Near-field surface plasmon effects on Au-double-slit diffraction for polychromatic light

    PubMed Central

    2014-01-01

    The surface plasmon effects on near-field diffraction for polychromatic light are studied. An Au-double-slit is used as the model and Fresnel integral is employed to perform the theoretic analysis. The results are illustrated with numerical examples and they show that, compared with the normal double-slit, the plasmon effect changes the spectral shift from redshift to blueshift and also enhances the intensity peak. This effect can be used in optical data transmission or specific spectral selectors. PMID:25386100

  19. Revising organic vapour respirator cartridge change schedule: a case study of a paint plant in Iran.

    PubMed

    Karimi, Ali; Jahangiri, Mehdi; Zare Derisi, Forough; Nourozi, Mohammad Amin

    2013-01-01

    After having revised the change schedule for organic vapour respirator cartridges in a paint plant in Iran, we established that it did not provide adequate protection against organic vapours at some workplaces and needed shortening from (48 to 72) h to 4 h. The revision also showed that relying on odour thresholds as the primary means to determine the time to change a chemical cartridge was not effective and that the National Institute for Occupational Safety and Health (NIOSH) MultiVapor service life software program could be applied to develop cartridge change schedules adjusted to specific workplaces.

  20. Revising organic vapour respirator cartridge change schedule: a case study of a paint plant in Iran.

    PubMed

    Karimi, Ali; Jahangiri, Mehdi; Zare Derisi, Forough; Nourozi, Mohammad Amin

    2013-01-01

    After having revised the change schedule for organic vapour respirator cartridges in a paint plant in Iran, we established that it did not provide adequate protection against organic vapours at some workplaces and needed shortening from (48 to 72) h to 4 h. The revision also showed that relying on odour thresholds as the primary means to determine the time to change a chemical cartridge was not effective and that the National Institute for Occupational Safety and Health (NIOSH) MultiVapor service life software program could be applied to develop cartridge change schedules adjusted to specific workplaces. PMID:23585165

  1. Ultrafast vapourization dynamics of laser-activated polymeric microcapsules

    NASA Astrophysics Data System (ADS)

    Lajoinie, Guillaume; Gelderblom, Erik; Chlon, Ceciel; Böhmer, Marcel; Steenbergen, Wiendelt; de Jong, Nico; Manohar, Srirang; Versluis, Michel

    2014-04-01

    Precision control of vapourization, both in space and time, has many potential applications; however, the physical mechanisms underlying controlled boiling are not well understood. The reason is the combined microscopic length scales and ultrashort timescales associated with the initiation and subsequent dynamical behaviour of the vapour bubbles formed. Here we study the nanoseconds vapour bubble dynamics of laser-heated single oil-filled microcapsules using coupled optical and acoustic detection. Pulsed laser excitation leads to vapour formation and collapse, and a simple physical model captures the observed radial dynamics and resulting acoustic pressures. Continuous wave laser excitation leads to a sequence of vapourization/condensation cycles, the result of absorbing microcapsule fragments moving in and out of the laser beam. A model incorporating thermal diffusion from the capsule shell into the oil core and surrounding water reveals the mechanisms behind the onset of vapourization. Excellent agreement is observed between the modelled dynamics and experiment.

  2. The tail effect on the shape of an electrical double layer differential capacitance curve

    NASA Astrophysics Data System (ADS)

    Henderson, Douglas; Lamperski, Stanisław; Bari Bhuiyan, Lutful; Wu, Jianzhong

    2013-04-01

    The differential capacitance curve for the double layer formed by an electrolyte dissolved in a solvent is commonly believed to be parabolic-like with a minimum at low electrolyte charge concentration and low electrode surface charge density, and independent of electrolyte concentration at high electrolyte concentrations and high electrode charge and would be, in the absence of solvent effects, featureless at these latter conditions. This is the prediction of the popular Gouy-Chapman-Stern theory. In contrast, for an ionic liquid this curve can have a single or a double hump (or a bell or camel shape). Fedorov et al. [Electrochem. Commun. 12, 296 (2010)], 10.1016/j.elecom.2009.12.019 have related these humps, particularly the double hump, to the neutral tails of ions in many ionic liquids. Evidence presented here shows, however, that such humps are general features of the differential capacitance of a double layer, whether it be formed by ions with or without a neutral tail. The presence of a double or single hump results from the magnitude of the electrolyte charge concentration. For both spherical ions or non-spherical ions consisting of charged heads and neutral tails, the shape of the differential capacitance transforms continuously from a double hump to a single hump as the electrolyte concentration is increased.

  3. Nonempirical Double-Hybrid Functionals: An Effective Tool for Chemists.

    PubMed

    Brémond, Eric; Ciofini, Ilaria; Sancho-García, Juan Carlos; Adamo, Carlo

    2016-08-16

    Density functional theory (DFT) emerged in the last two decades as the most reliable tool for the description and prediction of properties of molecular systems and extended materials, coupling in an unprecedented way high accuracy and reasonable computational cost. This success rests also on the development of more and more performing density functional approximations (DFAs). Indeed, the Achilles' heel of DFT is represented by the exchange-correlation contribution to the total energy, which, being unknown, must be approximated. Since the beginning of the 1990s, global hybrids (GH) functionals, where an explicit dependence of the exchange-correlation energy on occupied Kohn-Sham orbitals is introduced thanks to a fraction of Hartree-Fock-like exchange, imposed themselves as the most reliable DFAs for chemical applications. However, if these functionals normally provide results of sufficient accuracy for most of the cases analyzed, some properties, such as thermochemistry or dispersive interactions, can still be significantly improved. A possible way out is represented by the inclusion, into the exchange-correlation functional, of an explicit dependence on virtual Kohn-Sham orbitals via perturbation theory. This leads to a new class of functionals, called double-hybrids (DHs). In this Account, we describe our nonempirical approach to DHs, which, following the line traced by the Perdew-Burke-Ernzerhof approach, allows for the definition of a GH (PBE0) and a DH (QIDH) model. In such a way, a whole family of nonempirical functionals, spanning on the highest rungs of the Perdew's quality scale, is now available and competitive with other-more empirical-DFAs. Discussion of selected cases, ranging from thermochemistry and reactions to weak interactions and excitation energies, not only show the large range of applicability of nonempirical DFAs, but also underline how increasing the number of theoretical constraints parallels with an improvement of the DFA's numerical

  4. EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Dynamics of a plasma formed by a surface optical-discharge in a metal vapour interacting with a cw CO2 laser beam

    NASA Astrophysics Data System (ADS)

    Zaikin, A. E.; Levin, A. V.; Petrov, A. L.

    1995-02-01

    A surface optical-discharge plasma was formed in a metal vapour under normal conditions by steady-state irradiation with a cw CO2 laser delivering radiation of moderate (2-4.5 MW cm-2) intensity. This plasma strongly screened the irradiated surface. Under the selected experimental conditions the optical discharge was not a continuous (steady-state) process. The plasma cloud was displaced along the beam out of the waist to a region where the laser radiation intensity was almost an order of magnitude less than the threshold for excitation of the optical-discharge plasma in the vapour. A strong screening of the metal surface, which could even completely stop evaporation of the metal, was observed. Self-oscillations of the optical-discharge plasma were observed for the first time in a vapour interacting with cw CO2 radiation: this was attributed to screening of the target surface. Within one period of the self-oscillations there were additional hf plasma pulsations which led to stratification of the plasma cloud. The results obtained were interpreted.

  5. Biocompatibility of chemical-vapour-deposited diamond.

    PubMed

    Tang, L; Tsai, C; Gerberich, W W; Kruckeberg, L; Kania, D R

    1995-04-01

    The biocompatibility of chemical-vapour-deposited (CVD) diamond surfaces has been assessed. Our results indicate that CVD diamond is as biocompatible as titanium (Ti) and 316 stainless steel (SS). First, the amount of adsorbed and 'denatured' fibrinogen on CVD diamond was very close to that of Ti and SS. Second, both in vitro and in vivo there appears to be less cellular adhesion and activation on the surface of CVD diamond surfaces compared to Ti and SS. This evident biocompatibility, coupled with the corrosion resistance and notable mechanical integrity of CVD diamond, suggests that diamond-coated surfaces may be highly desirable in a number of biomedical applications. PMID:7654876

  6. Textile damage caused by vapour cloud explosions.

    PubMed

    Was-Gubala, J; Krauss, W

    2004-01-01

    The aim of the project was to investigate the damage to garments caused by particular vapour cloud explosions. The authors would like to be able to provide investigators with specific information on how to link clothes to a specific type of crime: a particular case study was the inspiration for the examinations. Experiments were carried out in the fire reconstruction chamber of the laboratory using a selection of 26 clothes and 15 household garments differing in colour, fibre composition and textile construction. PMID:15527183

  7. Variability of water vapour in the Arctic stratosphere

    NASA Astrophysics Data System (ADS)

    Thölix, Laura; Backman, Leif; Kivi, Rigel; Karpechko, Alexey Yu.

    2016-04-01

    This study evaluates the stratospheric water vapour distribution and variability in the Arctic. A FinROSE chemistry transport model simulation covering the years 1990-2014 is compared to observations (satellite and frost point hygrometer soundings), and the sources of stratospheric water vapour are studied. In the simulations, the Arctic water vapour shows decadal variability with a magnitude of 0.8 ppm. Both observations and the simulations show an increase in the water vapour concentration in the Arctic stratosphere after the year 2006, but around 2012 the concentration started to decrease. Model calculations suggest that this increase in water vapour is mostly explained by transport-related processes, while the photochemically produced water vapour plays a relatively smaller role. The increase in water vapour in the presence of the low winter temperatures in the Arctic stratosphere led to more frequent occurrence of ice polar stratospheric clouds (PSCs) in the Arctic vortex. We perform a case study of ice PSC formation focusing on January 2010 when the polar vortex was unusually cold and allowed large-scale formation of PSCs. At the same time a large-scale persistent dehydration was observed. Ice PSCs and dehydration observed at Sodankylä with accurate water vapour soundings in January and February 2010 during the LAPBIAT (Lapland Atmosphere-Biosphere facility) atmospheric measurement campaign were well reproduced by the model. In particular, both the observed and simulated decrease in water vapour in the dehydration layer was up to 1.5 ppm.

  8. Static Analysis of Double Effect Adsorption Refrigeration Cycle Using Silica gel/Water Pair

    NASA Astrophysics Data System (ADS)

    Marlinda; Miyazaki, Takahiko; Ueda, Yuki; Akisawa, Atsushi

    In this paper,a static analysis of double effect adsorption refrigeration cycle utilizing condensation heat is discussed. Double effect adsorption refrigeration cycle consists of two cycles, High Temperature Cycle (HTC) which is driven from external heat sources, and Low Temperature Cycle (LTC) which is driven by condensation heat from HTC. Both of HTC and LTC are using silica gel and water as working pairs. The effect of heat source temperature on cycle performance was investigated in terms of coefficient of performance (COP) and specific cooling energy (SCE). Results showed that double effect cycle would produce higher COP than single effect cycle for driving temperature observed between 80-150°C with the same operating condition. However, the value of SCE is lower than single effect, despite that the SCE of double effect cycle is improved with heat source temperature higher than 100°C. Further, it was also observed that adsorbent mass ratio of HTC and LTC affected performance of chiller. When adsorbent mass ratio of HTC and LTC was unity, it was found that SCE and COP took the maximum.

  9. Triple-effect absorption refrigeration system with double-condenser coupling

    DOEpatents

    DeVault, Robert C.; Biermann, Wendell J.

    1993-01-01

    A triple effect absorption refrigeration system is provided with a double-condenser coupling and a parallel or series circuit for feeding the refrigerant-containing absorbent solution through the high, medium, and low temperature generators utilized in the triple-effect system. The high temperature condenser receiving vaporous refrigerant from the high temperature generator is double coupled to both the medium temperature generator and the low temperature generator to enhance the internal recovery of heat within the system and thereby increase the thermal efficiency thereof.

  10. Triple-effect absorption refrigeration system with double-condenser coupling

    DOEpatents

    DeVault, R.C.; Biermann, W.J.

    1993-04-27

    A triple effect absorption refrigeration system is provided with a double-condenser coupling and a parallel or series circuit for feeding the refrigerant-containing absorbent solution through the high, medium, and low temperature generators utilized in the triple-effect system. The high temperature condenser receiving vaporous refrigerant from the high temperature generator is double coupled to both the medium temperature generator and the low temperature generator to enhance the internal recovery of heat within the system and thereby increase the thermal efficiency thereof.

  11. Vibration-rotation double resonance effects in symmetrical top molecules.

    NASA Technical Reports Server (NTRS)

    Marantz, H.; Frenkel, L.; Sullivan, T.

    1971-01-01

    Rotational transitions in symmetrical top molecules in the wavelength regions of 1-3 mm are sufficiently strong to be observed directly on an oscilloscope. Changes in the vibrational level populations induced by laser radiations affect the intensity of the rotational transitions. Observation of the microwave lines under the influence of chopped laser radiation shows a variety of interesting and potentially informative effects. At pressures above a few tenths of a torr the effect of laser radiation is to reduce the microwave response. This is true for all microwave lines at all those laser frequencies which are absorbed by the gas, and this effect is roughly proportional to the absorption coefficient. The rise and decay times of this effect increase with pressure and the the linear dimensions of the absorption cell. At low pressures the microwave response may increase, decrease, or remain unaffected depending on the observed microwave transitions and the specific laser line applied to the gas.

  12. Double robust estimator of average causal treatment effect for censored medical cost data.

    PubMed

    Wang, Xuan; Beste, Lauren A; Maier, Marissa M; Zhou, Xiao-Hua

    2016-08-15

    In observational studies, estimation of average causal treatment effect on a patient's response should adjust for confounders that are associated with both treatment exposure and response. In addition, the response, such as medical cost, may have incomplete follow-up. In this article, a double robust estimator is proposed for average causal treatment effect for right censored medical cost data. The estimator is double robust in the sense that it remains consistent when either the model for the treatment assignment or the regression model for the response is correctly specified. Double robust estimators increase the likelihood the results will represent a valid inference. Asymptotic normality is obtained for the proposed estimator, and an estimator for the asymptotic variance is also derived. Simulation studies show good finite sample performance of the proposed estimator and a real data analysis using the proposed method is provided as illustration. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Double robust estimator of average causal treatment effect for censored medical cost data.

    PubMed

    Wang, Xuan; Beste, Lauren A; Maier, Marissa M; Zhou, Xiao-Hua

    2016-08-15

    In observational studies, estimation of average causal treatment effect on a patient's response should adjust for confounders that are associated with both treatment exposure and response. In addition, the response, such as medical cost, may have incomplete follow-up. In this article, a double robust estimator is proposed for average causal treatment effect for right censored medical cost data. The estimator is double robust in the sense that it remains consistent when either the model for the treatment assignment or the regression model for the response is correctly specified. Double robust estimators increase the likelihood the results will represent a valid inference. Asymptotic normality is obtained for the proposed estimator, and an estimator for the asymptotic variance is also derived. Simulation studies show good finite sample performance of the proposed estimator and a real data analysis using the proposed method is provided as illustration. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26818601

  14. Spatial compatibility interference effects: a double dissociation between two measures

    PubMed Central

    Kirkham, Alexander J.; Tipper, Steven P.

    2015-01-01

    ABSTRACT In spatial compatibility tasks, when the spatial location of a stimulus is irrelevant it nevertheless interferes when a response is required in a different spatial location. For example, response with a left key-press is slowed when the stimulus is presented to the right as compared to the left side of a computer screen. However, in some conditions this interference effect is not detected in reaction time (RT) measures. It is typically assumed that the lack of effect means the irrelevant spatial code was not analysed or that the information rapidly decayed before response. However, we show that even in conditions where there appears to be no spatial interference when measuring RTs, effects can nevertheless be detected after response when recording facial electromyography responses. This dissociation between two measures highlights the importance of diverging methods to investigate visuomotor processes as conclusions based on only one measure can be misleading. PMID:26924937

  15. The beauty of frost: nano-sulfur assembly via low pressure vapour deposition.

    PubMed

    Wang, Yu; Chen, Lu; Scudiero, Louis; Zhong, Wei-Hong

    2015-11-14

    A low pressure vapour deposition (LPVD) technique is proposed as an environmentally friendly, cost-effective and versatile strategy for fabrication of sulfur nanomaterials. By controlling the characteristics of the deposit substrate for the LPVD, various sulfur-based nanomaterials have been obtained through a substrate-induced self-assembly process.

  16. Is there a solar signal in lower stratospheric water vapour?

    NASA Astrophysics Data System (ADS)

    Schieferdecker, Tobias; Lossow, Stefan; Stiller, Gabriele; von Clarmann, Thomas

    2016-04-01

    A merged time series of stratospheric water vapour built from the Halogen Occultation Instrument (HALOE) and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) data between 60 deg S and 60 deg N and 15 to 30 km, and covering the years 1992 to 2012, was analysed by multivariate linear regression, including an 11-year solar cycle proxy. Lower stratospheric water vapour was found to reveal a phase-shifted anti-correlation with the solar cycle, with lowest water vapour after solar maximum. The phase shift is composed of an inherent constant time lag of about 2 years and a second component following the stratospheric age of air. The amplitudes of the water vapour response are largest close to the tropical tropopause (up to 0.35 ppmv) and decrease with altitude and latitude. Including the solar cycle proxy in the regression results in linear trends of water vapour being negative over the full altitude/latitude range, while without the solar proxy, positive water vapour trends in the lower stratosphere were found. We conclude from these results that a solar signal seems to be generated at the tropical tropopause which is most likely imprinted on the stratospheric water vapour abundances and transported to higher altitudes and latitudes via the Brewer-Dobson circulation. Hence it is concluded that the tropical tropopause temperature at the final dehydration point of air may also be governed to some degree by the solar cycle. The negative water vapour trends obtained when considering the solar cycle impact on water vapour abundances can possibly solve the "water vapour conundrum" of increasing stratospheric water vapour abundances despite constant or even decreasing tropopause temperatures.

  17. Is there a solar signal in lower stratospheric water vapour?

    NASA Astrophysics Data System (ADS)

    Schieferdecker, T.; Lossow, S.; Stiller, G. P.; von Clarmann, T.

    2015-09-01

    A merged time series of stratospheric water vapour built from the Halogen Occultation Instrument (HALOE) and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) data between 60° S and 60° N and 15 to 30 km and covering the years 1992 to 2012 was analysed by multivariate linear regression, including an 11-year solar cycle proxy. Lower stratospheric water vapour was found to reveal a phase-shifted anti-correlation with the solar cycle, with lowest water vapour after solar maximum. The phase shift is composed of an inherent constant time lag of about 2 years and a second component following the stratospheric age of air. The amplitudes of the water vapour response are largest close to the tropical tropopause (up to 0.35 ppmv) and decrease with altitude and latitude. Including the solar cycle proxy in the regression results in linear trends of water vapour being negative over the full altitude/latitude range, while without the solar proxy, positive water vapour trends in the lower stratosphere were found. We conclude from these results that a solar signal seems to be generated at the tropical tropopause which is most likely imprinted on the stratospheric water vapour abundances and transported to higher altitudes and latitudes via the Brewer-Dobson circulation. Hence it is concluded that the tropical tropopause temperature at the final dehydration point of air may also be governed to some degree by the solar cycle. The negative water vapour trends obtained when considering the solar cycle impact on water vapour abundances can possibly solve the "water vapour conundrum" of increasing stratospheric water vapour abundances despite constant or even decreasing tropopause temperatures.

  18. Variations in mid tropospheric carbon dioxide, temperature and water vapour using satellite data during 2003-2011

    NASA Astrophysics Data System (ADS)

    Dhaka, Surendra

    2016-07-01

    In this presentation global, hemispherical and regional (India) variations in carbon dioxide, temperature and water vapour and their association is analysed using mid-tropospheric (300-500 hPa) Atmospheric Infra-red Sounder (AIRS) data for a period of 9 years (2003-2011). Mid-tropospheric carbon dioxide is observed to rise from ~372.61 ppm to ~392.94 ppm over the globe and 373.38 ppm to 392.48 ppm over India from 2003 to 2011. However no significant changes are observed in mid-tropospheric temperature and water vapour variations for the same period. De-trended data of temperature and water vapour shows a high correlation between them, but no significant correlation was observed between temperature and carbon dioxide over the studied regions. The absence of immediate co-relation between temperature and carbon dioxide is the evidence that rise in carbon dioxide in the atmosphere will not imply more absorption over the earth surface. This may be explained because of the absorbing effect of carbon dioxide which is very small as compared to water vapour. The role of water vapour is reinforced because unlike carbon dioxide, water vapour in the atmosphere is changing in tune with temperature.

  19. A double-slit experiment for non-classical interference effects in decision making.

    PubMed

    La Mura, Pierfrancesco

    2014-01-01

    We discuss the possible nature and role of non-physical entanglement, and the classical vs. non-classical interface, in models of human decision-making. We also introduce an experimental setting designed after the double-slit experiment in physics, and discuss how it could be used to discriminate between classical and non-classical interference effects in human decisions. PMID:24259289

  20. A double-slit experiment for non-classical interference effects in decision making.

    PubMed

    La Mura, Pierfrancesco

    2014-01-01

    We discuss the possible nature and role of non-physical entanglement, and the classical vs. non-classical interface, in models of human decision-making. We also introduce an experimental setting designed after the double-slit experiment in physics, and discuss how it could be used to discriminate between classical and non-classical interference effects in human decisions.

  1. The effectiveness of double hulls in reducing vessel-accident oil spillage.

    PubMed

    Yip, Tsz Leung; Talley, Wayne K; Jin, Di

    2011-11-01

    While much work has been done in investigating determinants of oil spillage attributed to vessel accidents, little research has been conducted on the effectiveness of ship hull design in reducing marine pollution. This paper addresses whether the double-hull requirement reduces vessel-accident oil spillage. The volume of oil spillage due to oil-cargo vessel accidents was investigated using tobit regressions and an empirical data set of individual vessel accident pollution incidents investigated by the US Coast Guard from 2001 to 2008. The results indicate that the double hull design on average reduces the size of oil spills by 20% and 62% in tank barge and tanker ship accidents, respectively.

  2. Reduction of the Shupe effect in interferometric fiber optic gyroscopes: The double cylinder-wound coil

    NASA Astrophysics Data System (ADS)

    Ling, Weiwei; Li, Xuyou; Yang, Hanrui; Liu, Pan; Xu, Zhenlong; Wei, Yanhui

    2016-07-01

    For the first time, we introduce a novel double-cylinder winding method for reducing the Shupe effect in interferometric fiber optic gyroscopes (IFOGs). Simulation by finite element method (FEM) is performed to calculate the dynamic temperature distribution of fiber coils, which can obtained thermal-induced rate errors in IFOGs with cross-wound coil and double cylinder-wound coil respectively. Simulation results reveal that thermal-induced rate errors in IFOGs by both winding methods can be substantially reduced under the same variable temperature conditions, but the latter has a simpler winding technology. This study is promising for reducing the temperature fragility of IFOGs.

  3. Self-reported effectiveness of double-fine zones as a speed control measure.

    PubMed

    Jones, Barnie; Haas, Kevin; Kirk, Alan; Griffith, Andrew

    2004-01-01

    This study evaluated the effectiveness of signs alerting drivers to double traffic fines in highway work zones, school zones and safety corridors. The evaluation was based on a driver survey that investigated the decision to exceed speed limits across a range of driving contexts and risk categories. The findings indicated that personal assessments of risk change from one hypothetical situation to another, suggesting that people make a more or less calculated decision to violate the speed limit, based on those risks. The findings also suggested that people perceive a higher relative risk associated with traffic fines if the situation is one in which a doubling of traffic fines may apply. Finally, the results showed that interview subjects who reported being aware of double-fine zones tended to have somewhat higher assessments of the risk associated with traffic citations, traffic fines and higher insurance rates.

  4. Double resonant wideband Purcell effect in wire metamaterials

    NASA Astrophysics Data System (ADS)

    Mirmoosa, M. S.; Kosulnikov, S. Yu; Simovski, C. R.

    2016-09-01

    In this paper, we theoretically show that a broadband resonant enhancement of emission may occur for infrared sources located in a polaritonic wire medium. The reason for this enhancement is the overlapping of two topological transitions of the wave dispersion in the medium. The first topological transition has been revealed as an effect inherent to polaritonic wire media at a certain frequency in the mid-infrared range. This work uncovers another topological transition for such wire media which holds at a higher frequency but still in the mid infrared. We show that the first transition frequency can be shifted towards the second one by variation of the design parameters. This shift enables a broadband resonant Purcell factor. We compare the results obtained for two orientations of a subwavelength electric dipole embedded into the wire medium—that along the optical axis and that perpendicular to it—and report on the resonant isotropic radiation enhancement. Also, we reveal the enhancement of radiation to the free space from a finite sample of the wire medium.

  5. Speciation of mercury in fish samples by flow injection catalytic cold vapour atomic absorption spectrometry.

    PubMed

    Zhang, Yanlin; Adeloju, Samuel B

    2012-04-01

    A rapid flow injection catalytic cold vapour atomic absorption spectrometric (FI-CCV-AAS) method is described for speciation and determination of mercury in biological samples. Varying concentrations of NaBH(4) were employed for mercury vapour generation from inorganic and mixture of inorganic and organic (total) Hg. The presence of Fe(3+), Cu(2+) and thiourea had catalytic effect on mercury vapour generation from methylmercury (MeHg) and, when together, Cu(2+) and thiourea had synergistic catalytic effect on the vapour generation. Of the two metal ions, Fe(3+) gave the best sensitivity enhancement, achieving the same sensitivity for MeHg and inorganic Hg(2+). Due to similarity of resulting sensitivity, Hg(2+) was used successfully as a primary standard for quantification of inorganic and total Hg. The catalysis was homogeneous in nature, and it was assumed that the breaking of the C-Hg bond was facilitated by the delocalization of the 5d electron pairs in Hg atom. The extraction of MeHg and inorganic mercury (In-Hg) in fish samples were achieved quantitatively with hydrochloric acid in the presence of thiourea and determined by FI-CCV-AAS. The application of the method to the quantification of mercury species in a fish liver reference material DOLT-4 gave 91.5% and 102.3% recoveries for total and methyl mercury, respectively. The use of flow injection enabled rapid analysis with a sample throughput of 180 h(-1).

  6. Age and structure of a model vapour-deposited glass

    PubMed Central

    Reid, Daniel R.; Lyubimov, Ivan; Ediger, M. D.; de Pablo, Juan J.

    2016-01-01

    Glass films prepared by a process of physical vapour deposition have been shown to have thermodynamic and kinetic stability comparable to those of ordinary glasses aged for thousands of years. A central question in the study of vapour-deposited glasses, particularly in light of new knowledge regarding anisotropy in these materials, is whether the ultra-stable glassy films formed by vapour deposition are ever equivalent to those obtained by liquid cooling. Here we present a computational study of vapour deposition for a two-dimensional glass forming liquid using a methodology, which closely mimics experiment. We find that for the model considered here, structures that arise in vapour-deposited materials are statistically identical to those observed in ordinary glasses, provided the two are compared at the same inherent structure energy. We also find that newly deposited hot molecules produce cascades of hot particles that propagate far into the film, possibly influencing the relaxation of the material. PMID:27762262

  7. Effects of double transport and season on sensorial aspects of lamb's meat quality in dry climates.

    PubMed

    Miranda-de la Lama, Genaro C; Villarroel, Morris; Campo, María del Mar; Olleta, José Luis; Sañudo, Carlos; María, Gustavo A

    2012-01-01

    The objective of the current study was to analyse the effects of double transport and season on sensorial aspects of lamb's meat quality in dry climates. A total of 144 lambs were sampled in a 3 × 2 × 2 factorial design, testing three types of double transport along the residence time at a pre-slaughter classification centre or CC (0, 7 and 28 days) and two seasons (summer and winter), with two replicates in each season. Meat from the M. longissimus was analysed in terms of pH and WHC and tasted by a trained sensory panel in terms of lamb odour intensity, tenderness, juiciness, lamb flavour intensity, fat flavour intensity, liver flavour intensity, metallic flavour intensity and overall liking. Meat sensorial quality traits were not significantly affected by double transport. Season had a significant (P<0.001) effect on all variables analysed, except for lamb flavour intensity and overall liking. Interactions between the fixed effects were not significant, with the exception of tenderness. Season significantly affects several sensorial variables, and they seem to be independent of double transport, with the exception of tenderness. PMID:22072077

  8. A solar signal in lower stratospheric water vapour?

    NASA Astrophysics Data System (ADS)

    Schieferdecker, T.; Lossow, S.; Stiller, G. P.; von Clarmann, T.

    2015-04-01

    A merged time series of stratospheric water vapour built from HALOE and MIPAS data between 60° S and 60° N and 15 to 30 km and covering the years 1992 to 2012 was analyzed by multivariate linear regression including an 11 year solar cycle proxy. Lower stratospheric water vapour was found to reveal a phase-shifted anti-correlation with the solar cycle, with lowest water vapour after solar maximum. The phase shift is composed of an inherent constant time lag of about 2 years and a second component following the stratospheric age of air. The amplitudes of the water vapour response are largest close to the tropical tropopause (up to 0.35 ppmv) and decrease with altitude and latitude. Including the solar cycle proxy in the regression results in linear trends of water vapour being negative over the full altitude/latitude range, while without the solar proxy positive water wapour trends in the lowermost stratosphere were found. We conclude from these results that a solar signal generated at the tropical tropopause is imprinted on the stratospheric water vapour abundances and transported to higher altitudes and latitudes via the Brewer-Dobson circulation. Hence it is concluded that the tropical tropopause temperature at the final dehydration point of air is also governed to some degree by the solar cycle. The negative water vapour trends obtained when considering the solar cycle impact on water vapour abundances can solve the water vapour conundrum of increasing stratospheric water vapour abundances at constant or even decreasing tropopause temperatures.

  9. Developments in vapour cloud explosion blast modeling.

    PubMed

    Mercx, W P; van den Berg, A C; Hayhurst, C J; Robertson, N J; Moran, K C

    2000-01-01

    TNT Equivalency methods are widely used for vapour cloud explosion blast modeling. Presently, however, other types of models are available which do not have the fundamental objections TNT Equivalency models have. TNO Multi-Energy method is increasingly accepted as a more reasonable alternative to be used as a simple and practical method. Computer codes based on computational fluid dynamics (CFD) like AutoReaGas, developed by TNO and Century Dynamics, could be used also in case a more rigorous analysis is required. Application of the Multi-Energy method requires knowledge of two parameters describing the explosion: a charge size and a charge strength. During the last years, research has led to an improved determination of the charge strength (i.e., the class number or source overpressure) to be chosen to apply the blast charts. A correlation has been derived relating the charge strength to a set of parameters describing the boundary conditions of the flammable cloud and the fuel in the cloud. A simple approach may not be satisfactory in all situations. The overpressure distribution inside a vapour cloud explosion is generally not homogeneous and the presence of obstructions causes directional blast propagation in the near field. A CFD approach, in which the actual situation is modeled, supplies case-specific results. An overview of the key aspects relevant to the application of the Multi-Energy method and CFD modeling is provided. Then the application of the two methods is demonstrated for an example problem involving the calculation of the explosion blast load on a structure at some distance from the explosion in an offshore platform complex.

  10. 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.

  11. Evaluation of the biological efficacy of hydrogen peroxide vapour decontamination in wards of an Australian hospital.

    PubMed

    Chan, H-T; White, P; Sheorey, H; Cocks, J; Waters, M-J

    2011-10-01

    This study assessed the efficacy of a 'dry' hydrogen peroxide vapour decontamination in an Australian hospital via a two-armed study. The in vivo arm examined the baseline bacterial counts in high-touch zones within wards and evaluated the efficacy of cleaning with a neutral detergent followed by either hydrogen peroxide vapour decontamination, or a manual terminal clean with bleach or Det-Sol 500. The in vitro arm examined the efficacy of hydrogen peroxide vapour decontamination on a variety of different surfaces commonly found in the wards of an Australian hospital, deliberately seeded with a known concentration of vancomycin-resistant enterococci (VRE). All bacterial counts were evaluated by a protocol of contact plate method. In the in vivo arm, 33.3% of the high-touch areas assessed had aerobic bacterial count below the detection limit (i.e. no bacteria recoverable) post hydrogen peroxide decontamination, and in all circumstances the highest microbial density was ≤3 cfu/cm(2), while in the in vitro arm there was at least a reduction in bacterial load by a factor of 10 at all surfaces investigated. These results showed that dry hydrogen peroxide vapour room decontamination is highly effective on a range of surfaces, although the cleanliness data obtained by these methods cannot be easily compared among the different surfaces as recovery of organisms is affected by the nature of the surface.

  12. Understanding vapour plume structure in indoor environments for the detection of explosives

    NASA Astrophysics Data System (ADS)

    Foat, Tim

    2015-11-01

    Dogs remain the most effective method for the detection of explosives in many situations yet the spatially, temporally and chemically varying signature that they sense cannot easily be quantified. Vapour plumes can be highly unsteady and intermittent and the problem is further complicated in indoor spaces where turbulent, transitional and laminar regions may exist and where there may be no dominant flow direction. Intermittent plumes can have peak concentrations that are considerably higher than the time averaged values. As dogs can sample the air at 5 Hz it is possible that these unsteady fluctuations play a key part in their detection process. A low Reynolds number (Re less than 5000 at the inlet) benchmark test case for indoor airflow has been studied using large-eddy simulation computational fluid dynamics. Fixed concentration vapour sources have been included on the floor of the room and the resulting vapour dispersion has been modelled. Sources with different surface areas have been included and their instantaneous and mean concentration profiles compared. The results from this study will provide insight into canine detection of vapour in indoor environments.

  13. Effect of ZnO nanoparticles in R290/R600a (50/50) based vapour compression refrigeration system added via lubricant oil on compressor suction and discharge characteristics

    NASA Astrophysics Data System (ADS)

    Kumar, Ravinder; Singh, Jagdev

    2016-10-01

    The primary source of energy consumption in a vapour compression refrigeration system is a compressor. The possibility of a reduction in the work of compression may leads to enhance the compressor suction and discharge characteristics and the overall performance of the refrigeration system. The present experimental investigation based upon the study of ZnO nanoparticles in a vapour compression refrigeration system using hydrocarbon blend R290/R600a (50/50) as a refrigerant. The zinc oxide nanoparticles are appended with system refrigerant via compressor lubricating oil. The results observed that by using different weight concentrations of nanoparticles in R290/R600a refrigeration system, both the compressor suction and discharge pressures and temperatures were reduced compared to conventional system. The viscosity of mineral oil with the addition of nanoparticles increases. The compressor energy consumption was reduced by 7.48 % using (0.2-1.0) wt% concentrations of nanoparticles. The COP of the refrigeration system has been increased by about 46 % with the addition of nanoparticles. Thus, the ZnO nanoparticles worked efficiently in the R290/R600a refrigeration system.

  14. U-shaped, double-tapered, fiber-optic sensor for effective biofilm growth monitoring.

    PubMed

    Zhong, Nianbing; Zhao, Mingfu; Li, Yishan

    2016-02-01

    To monitor biofilm growth on polydimethylsiloxane in a photobioreactor effectively, the biofilm cells and liquids were separated and measured using a sensor with two U-shaped, double-tapered, fiber-optic probes (Sen. and Ref. probes). The probes' Au-coated hemispherical tips enabled double-pass evanescent field absorption. The Sen. probe sensed the cells and liquids inside the biofilm. The polyimide-silica hybrid-film-coated Ref. probe separated the liquids from the biofilm cells and analyzed the liquid concentration. The biofilm structure and active biomass were also examined to confirm the effectiveness of the measurement using a simulation model. The sensor was found to effectively respond to the biofilm growth in the adsorption through exponential phases at thicknesses of 0-536 μm.

  15. U-shaped, double-tapered, fiber-optic sensor for effective biofilm growth monitoring.

    PubMed

    Zhong, Nianbing; Zhao, Mingfu; Li, Yishan

    2016-02-01

    To monitor biofilm growth on polydimethylsiloxane in a photobioreactor effectively, the biofilm cells and liquids were separated and measured using a sensor with two U-shaped, double-tapered, fiber-optic probes (Sen. and Ref. probes). The probes' Au-coated hemispherical tips enabled double-pass evanescent field absorption. The Sen. probe sensed the cells and liquids inside the biofilm. The polyimide-silica hybrid-film-coated Ref. probe separated the liquids from the biofilm cells and analyzed the liquid concentration. The biofilm structure and active biomass were also examined to confirm the effectiveness of the measurement using a simulation model. The sensor was found to effectively respond to the biofilm growth in the adsorption through exponential phases at thicknesses of 0-536 μm. PMID:26977344

  16. U-shaped, double-tapered, fiber-optic sensor for effective biofilm growth monitoring

    PubMed Central

    Zhong, Nianbing; Zhao, Mingfu; Li, Yishan

    2016-01-01

    To monitor biofilm growth on polydimethylsiloxane in a photobioreactor effectively, the biofilm cells and liquids were separated and measured using a sensor with two U-shaped, double-tapered, fiber-optic probes (Sen. and Ref. probes). The probes’ Au-coated hemispherical tips enabled double-pass evanescent field absorption. The Sen. probe sensed the cells and liquids inside the biofilm. The polyimide–silica hybrid-film-coated Ref. probe separated the liquids from the biofilm cells and analyzed the liquid concentration. The biofilm structure and active biomass were also examined to confirm the effectiveness of the measurement using a simulation model. The sensor was found to effectively respond to the biofilm growth in the adsorption through exponential phases at thicknesses of 0–536 μm. PMID:26977344

  17. Magnetohydrodynamic effects on a charged colloidal sphere with arbitrary double-layer thickness.

    PubMed

    Hsieh, Tzu H; Keh, Huan J

    2010-10-01

    An analytical study is presented for the magnetohydrodynamic (MHD) effects on a translating and rotating colloidal sphere in an arbitrary electrolyte solution prescribed with a general flow field and a uniform magnetic field at a steady state. The electric double layer surrounding the charged particle may have an arbitrary thickness relative to the particle radius. Through the use of a simple perturbation method, the Stokes equations modified with an electric force term, including the Lorentz force contribution, are dealt by using a generalized reciprocal theorem. Using the equilibrium double-layer potential distribution from solving the linearized Poisson-Boltzmann equation, we obtain closed-form formulas for the translational and angular velocities of the spherical particle induced by the MHD effects to the leading order. It is found that the MHD effects on the particle movement associated with the translation and rotation of the particle and the ambient fluid are monotonically increasing functions of κa, where κ is the Debye screening parameter and a is the particle radius. Any pure rotational Stokes flow of the electrolyte solution in the presence of the magnetic field exerts no MHD effect on the particle directly in the case of a very thick double layer (κa→0). The MHD effect caused by the pure straining flow of the electrolyte solution can drive the particle to rotate, but it makes no contribution to the translation of the particle.

  18. Experimental investigation of the Marangoni effect on the stability of a double-diffusive layer

    NASA Technical Reports Server (NTRS)

    Tanny, Josef; Chen, Chuan F.

    1994-01-01

    Stability experiments were carried out in 4-cm-thick, salt-stratified fluid layer by heating from below and cooling from above. The bottom boundary was rigid while the top was either free or rigid. The initial solute Rayleigh number varied from 2.5 x 10(exp 6) to 4.6 x 10(exp 7). For the rigid-free case, at initial solute Rayleigh numbers R(sub s) greater than 5.4 x 10(exp 6), thermal Marangoni instabilities were observed to onset along the free surface at a relatively low thermal Rayleigh number, R(sub t). The convection was very weak, and it had almost no effect on the concentration and temperature distributions. Double-diffusive instabilities along the top free surface were observed to onset at a higher R(sub t), with much stronger convection causing changes in the concentration and temperature distributions near the top. At a yet higher R(sub t), double-diffusive convection was observed to onset along the bottom boundary. Fluid motion in the layer then evolved into fully developed thermal convection of a homogeneous fluid without any further increase in the imposed Delta T. For layers with R(sub s) less than 5.4 x 10(exp 6), Marangoni and double-diffusive instabilities onset simultaneously along the free surface first, while double-diffusive instabilities along the bottom wall onset at a higher R(sub t).

  19. Effects of hot electron inertia on electron-acoustic solitons and double layers

    SciTech Connect

    Verheest, Frank; Hellberg, Manfred A.

    2015-07-15

    The propagation of arbitrary amplitude electron-acoustic solitons and double layers is investigated in a plasma containing cold positive ions, cool adiabatic and hot isothermal electrons, with the retention of full inertial effects for all species. For analytical tractability, the resulting Sagdeev pseudopotential is expressed in terms of the hot electron density, rather than the electrostatic potential. The existence domains for Mach numbers and hot electron densities clearly show that both rarefactive and compressive solitons can exist. Soliton limitations come from the cool electron sonic point, followed by the hot electron sonic point, until a range of rarefactive double layers occurs. Increasing the relative cool electron density further yields a switch to compressive double layers, which ends when the model assumptions break down. These qualitative results are but little influenced by variations in compositional parameters. A comparison with a Boltzmann distribution for the hot electrons shows that only the cool electron sonic point limit remains, giving higher maximum Mach numbers but similar densities, and a restricted range in relative hot electron density before the model assumptions are exceeded. The Boltzmann distribution can reproduce neither the double layer solutions nor the switch in rarefactive/compressive character or negative/positive polarity.

  20. Tunable Josephson effect in hybrid parallel coupled double quantum dot-superconductor tunnel junction

    NASA Astrophysics Data System (ADS)

    Rajput, Gagan; Kumar, Rajendra; Ajay

    2014-09-01

    Using non-equilibrium Green's function approach, we study electronic transport through a parallel double quantum dot (DQD) system symmetrically coupled to conventional superconducting leads. Andreev bound states (ABS) and corresponding resonant Cooper pair electron transmission through such a DQD-superconductor tunnel junction around the Fermi energy, a manifestation of Josephson effect, occur due to proximity effect as a result of superconducting order parameter. Interdot tunnel coupling in parallel coupled DQD system and Coulomb interactions regulate the Josephson effect in a very significant manner. Further, it is also found that interdot tunnel coupling has reverse effect on ABS and Cooper pair tunneling in the presence and absence of Coulomb interactions.

  1. [CO2-gas exchange of mosses following water vapour uptake].

    PubMed

    Lange, O L

    1969-03-01

    The CO2-gas exchange of dry mosses which were exposed to air of high water vapour content has been followed. Some moss species behave as do lichens and aerophilic green algae: they are able to take up enough water vapour to make a rather high photosynthetic activity possible. Other species lack this ability. They need liquid water for reactivation of photosynthesis, as do poikilohydric ferns and phanerogams. In this respect too the mosses are located between the real thallophytes and the cormophytes. From this point of view they are useful objects for studying the relationships between water vapour reactivation, morphological organisation and ecological capability.

  2. [CO2-gas exchange of mosses following water vapour uptake].

    PubMed

    Lange, O L

    1969-03-01

    The CO2-gas exchange of dry mosses which were exposed to air of high water vapour content has been followed. Some moss species behave as do lichens and aerophilic green algae: they are able to take up enough water vapour to make a rather high photosynthetic activity possible. Other species lack this ability. They need liquid water for reactivation of photosynthesis, as do poikilohydric ferns and phanerogams. In this respect too the mosses are located between the real thallophytes and the cormophytes. From this point of view they are useful objects for studying the relationships between water vapour reactivation, morphological organisation and ecological capability. PMID:24504355

  3. Effect of finite width on deflection and energy release rate of an orthotropic double cantilever specimen

    NASA Technical Reports Server (NTRS)

    Schapery, R. A.; Davidson, B. D.

    1988-01-01

    The problem of an orthotropic cantilevered plate subjected to a uniformly distributed end load is solved by the Rayleigh-Ritz energy method. The result is applied to laminated composite, double cantilevered specimens to estimate the effect of crack tip constraint on the transverse curvature, deflection and energy release rate. The solution is also utilized to determined finite width correction factors for fracture energy characterization tests in which neither plane stress nor plane strain conditions apply.

  4. Explicit drain current model of junctionless double-gate field-effect transistors

    NASA Astrophysics Data System (ADS)

    Yesayan, Ashkhen; Prégaldiny, Fabien; Sallese, Jean-Michel

    2013-11-01

    This paper presents an explicit drain current model for the junctionless double-gate metal-oxide-semiconductor field-effect transistor. Analytical relationships for the channel charge densities and for the drain current are derived as explicit functions of applied terminal voltages and structural parameters. The model is validated with 2D numerical simulations for a large range of channel thicknesses and is found to be very accurate for doping densities exceeding 1018 cm-3, which are actually used for such devices.

  5. Asymmetric effects on the optical properties of double-quantum well systems

    NASA Astrophysics Data System (ADS)

    Silotia, Poonam; Batra, Kriti; Prasad, Vinod

    2014-02-01

    Linear, nonlinear, and total absorption coefficient and refractive index changes of double-quantum well (DQW) systems are studied theoretically in the presence of external static electric field applied along the growth direction. The analytical expression for the linear and nonlinear optical properties is obtained using density matrix method. Emphasis is laid on the effect of asymmetry in the shapes of DQW system on optical properties. Some interesting results are obtained and explained.

  6. Parallel double-plate capacitive proximity sensor modelling based on effective theory

    SciTech Connect

    Li, Nan Zhu, Haiye; Wang, Wenyu; Gong, Yu

    2014-02-15

    A semi-analytical model for a double-plate capacitive proximity sensor is presented according to the effective theory. Three physical models are established to derive the final equation of the sensor. Measured data are used to determine the coefficients. The final equation is verified by using measured data. The average relative error of the calculated and the measured sensor capacitance is less than 7.5%. The equation can be used to provide guidance to engineering design of the proximity sensors.

  7. Superconductivity and the disorder effect in Ag and Al double doped MgB2

    NASA Astrophysics Data System (ADS)

    Shi, Lei; Zhang, Huarong; Zhou, Shiming; Zhao, Jiyin; Zuo, Jian

    2006-07-01

    A series of polycrystalline bulk samples of Mg1-2x(AgAl)xB2 (0.0%⩽x⩽1.0%) has been synthesized by a solid state reaction method. The structure, Raman spectrum, and superconducting properties have been investigated by x-ray diffraction, Raman spectroscopy, and low-temperature resistivity measurements. It is found that the Ag, Al double doping causes the expansion of crystal lattice along the a- and c-axis orientations due to the substitution inducing ionic size variation. A redshift of peak position is observed in Raman spectra, which is ascribed to the crystal cell volume change inducing the variation of the phonon frequency. The superconducting transition temperature (Tc) is degressive with the doping level (x) increase. By the Ag and Al double doping, the hole concentration is kept to be unchanged in MgB2, which eliminates the effects of the charge carrier concentration change and band filling on Tc. It is suggested that the reason of the Tc suppression caused by the double doping is the co-operating results of the disorder effect and the chemical pressure effect induced by the chemical substitution.

  8. Transient Adverse Side Effects During Neurofeedback Training: A Randomized, Sham-Controlled, Double Blind Study.

    PubMed

    Rogel, Ainat; Guez, Jonathan; Getter, Nir; Keha, Eldad; Cohen, Tzlil; Amor, Tali; Todder, Doron

    2015-09-01

    The benefits of clinical neurofeedback training are well known, however, its adverse side-effects are less studied. This research focuses on the transient adverse side effects of neurofeedback training via a double-blind, sham/controlled methodology. Thirty healthy undergraduate students volunteers were randomly divided into three treatment groups: increasing a modified Sensory Motor Rhythm, increasing Upper Alpha, and Sham/control group who receive a random reward. The training sessions were administered for a total of ten sessions. Questionnaires of transient adverse side effects were completed by all volunteers before each session. The results suggest that similar to most medical treatments, neurofeedback can cause transient adverse side effects. Moreover, most participants reported experiencing some side effects. The side effects can be divided into non-specific side effect, associated with the neurofeedback training in general and specific ones associated with the particular protocol. Sensory Motor Rhythm protocol seems to be the most sensitive to side effects.

  9. Trends and transport of water vapour in the middle atmosphere

    NASA Astrophysics Data System (ADS)

    Urban, Joachim

    2012-07-01

    J. Urban with data contributions from the SAGE, HALOE, Odin, MIPAS, ACE, MLS, and SABER teams The evolution and spatio-temporal variability of water vapour in the tropical tropopause region, stratosphere, and mesosphere is analyzed using "historical" (SAGE-II, UARS/HALOE) and "recent" (Odin/SMR, TIMED/SABER, ENVISAT/MIPAS, ACE/FTS, Aura/MLS) satellite limb measurements. Water vapour mixing ratios in the tropical lower stratosphere are correlated with changes of the very variable tropical tropopause cold-point temperatures and the water vapour entry signal is further modulated and altered by transport and mixing of air masses. A water vapour signal originating and ascending in the tropical tropopause region can within certain limits be followed through the stratosphere and mesosphere allowing us for example to test consistency with "age-of-air" estimates and present understanding of poleward transport in this atmospheric region.

  10. Ammonia Diffusion through Nalophan Double Bags: Effect of Concentration Gradient Reduction

    PubMed Central

    Capelli, Laura; Boiardi, Emanuela; Del Rosso, Renato

    2014-01-01

    The ammonia loss through Nalophan bags has been studied. The losses observed for storage conditions and times as allowed by the reference standard for dynamic olfactometry (EN 13725:2003) indicate that odour concentration values due to the presence of small molecules may be significantly underestimated if samples are not analysed immediately after sampling. A diffusion model was used in order to study diffusion through the bag. The study discusses the effect of concentration gradient (ΔC) across the polymeric membrane of the analyte. The ΔC was controlled by using a setup bag called “double bags.” Experimental data show a reduction of ammonia percentage losses due to the effect of the external multibarrier. The expedient of the double bag loaded with the same gas mixture allows a reduced diffusion of ammonia into the inner bag. Comparing the inner bag losses with those of the single bag stored in the same conditions (T, P, u) and with equal geometrical characteristics (S/V, z), it was observed that the inner bag of the double bag displays a 16% loss while the single bag displays a 37% loss. Acting on the ΔC it is possible to achieve a gross reduction of 57% in the ammonia leakage due to diffusion. PMID:25506608

  11. Splitting of the resistive transition of copper oxide superconductors: Intrinsic double superconducting transitions versus extrinsic effects

    SciTech Connect

    Pomar, A.; Curras, S.R.; Veira, J.A.; Vidal, F.

    1996-04-01

    To prove the possible existence of an intrinsic double superconducting transition in the high-temperature copper oxide superconductors (HTSC), an effect recently attributed by various groups to different intrinsic properties of these materials (including unconventional wave pairing), we present in this paper high resolution data of the electrical resistivity, {rho}({ital T}), around the superconducting transition of different single crystal and polycrystal YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} samples. The analysis of the temperature derivative of these {rho}({ital T}) data strongly suggests that (i) with a temperature resolution well to within 20 mK, the intrinsic resistive transition of the HTSC does not present any double transition anomaly and (ii) the double peak structure observed in {ital d}{rho}({ital T})/{ital dT} by some authors is probably an extrinsic effect (associated with stoichiometric inhomogeneities in some cases, and with experimental artifacts in other cases). {copyright} {ital 1996 The American Physical Society.}

  12. The effectiveness of double hulls in reducing vessel-accident oil spillage.

    PubMed

    Yip, Tsz Leung; Talley, Wayne K; Jin, Di

    2011-11-01

    While much work has been done in investigating determinants of oil spillage attributed to vessel accidents, little research has been conducted on the effectiveness of ship hull design in reducing marine pollution. This paper addresses whether the double-hull requirement reduces vessel-accident oil spillage. The volume of oil spillage due to oil-cargo vessel accidents was investigated using tobit regressions and an empirical data set of individual vessel accident pollution incidents investigated by the US Coast Guard from 2001 to 2008. The results indicate that the double hull design on average reduces the size of oil spills by 20% and 62% in tank barge and tanker ship accidents, respectively. PMID:21924747

  13. Quantization effects on the inversion mode of a double gate MOS

    NASA Astrophysics Data System (ADS)

    Mondol, Kalyan; Hasan, Md. Manzurul; Arafath, Yeasir; Alam, Khairul

    We investigate the quantization effects on the gate capacitance and charge distribution of a double gate MOSFET using a self-consistent solution of Poisson and Schrödinger equations of the industry standard simulation package Silvaco. Quantization effects on the gate C-V are simulated by varying the electron and hole effective masses. We notice that the inversion capacitance value decreases as the effective mass goes below 0.1mo and the shape of the C-V curve changes to step like in the inversion. We also notice that the inversion switches from surface inversion to volume inversion for low effective mass, and the quantization effect (step like shape) in C-V and volume inversion in charge profile happen at the same effective mass.

  14. Cost-Effectiveness of Double Reading versus Single Reading of Mammograms in a Breast Cancer Screening Programme

    PubMed Central

    Posso, Margarita; Carles, Misericòrdia; Rué, Montserrat; Puig, Teresa; Bonfill, Xavier

    2016-01-01

    Objectives The usual practice in breast cancer screening programmes for mammogram interpretation is to perform double reading. However, little is known about its cost-effectiveness in the context of digital mammography. Our purpose was to evaluate the cost-effectiveness of double reading versus single reading of digital mammograms in a population-based breast cancer screening programme. Methods Data from 28,636 screened women was used to establish a decision-tree model and to compare three strategies: 1) double reading; 2) double reading for women in their first participation and single reading for women in their subsequent participations; and 3) single reading. We calculated the incremental cost-effectiveness ratio (ICER), which was defined as the expected cost per one additionally detected cancer. We performed a deterministic sensitivity analysis to test the robustness of the ICER. Results The detection rate of double reading (5.17‰) was similar to that of single reading (4.78‰; P = .768). The mean cost of each detected cancer was €8,912 for double reading and €8,287 for single reading. The ICER of double reading versus single reading was €16,684. The sensitivity analysis showed variations in the ICER according to the sensitivity of reading strategies. The strategy that combines double reading in first participation with single reading in subsequent participations was ruled out due to extended dominance. Conclusions From our results, double reading appears not to be a cost-effective strategy in the context of digital mammography. Double reading would eventually be challenged in screening programmes, as single reading might entail important net savings without significantly changing the cancer detection rate. These results are not conclusive and should be confirmed in prospective studies that investigate long-term outcomes like quality adjusted life years (QALYs). PMID:27459663

  15. Thermoelectric effects in a double quantum dot system weakly coupled to ferromagnetic leads

    NASA Astrophysics Data System (ADS)

    Tagani, M. Bagheri; Soleimani, H. Rahimpour

    2012-05-01

    Thermoelectric effects through a serial double quantum dot system weakly coupled to ferromagnetic leads are analyzed. Formal expressions of electrical conductance, thermal conductance, and thermal coefficient are obtained by means of Hubbard operators. The results show that although the thermopower is independent of the polarization of the leads, the figure of merit is reduced by an increase of polarization. The influences of temperature and interdot tunneling on the figure of merit are also investigated, and it is observed that increase of the interdot tunneling strength results in reduction of the figure of merit. The effect of temperature on the thermal conductance is also analyzed.

  16. Effects of mixed discrete surface charges on the electrical double layer.

    PubMed

    Jiménez-Ángeles, Felipe

    2012-08-01

    Adsorption of surface coions and charge reversal are induced at the electrical double layer of a wall charged with positive and negative surface sites next to an electrolyte solution. While for the considered surface charge density these effects are found over a wide range of conditions, they are not observed for the typically employed surface models in equivalent conditions. Important consequences in electrophoresis experiments for different colloids with equal effective surface charge density are foreseen. This study is carried out by means of molecular dynamics simulations.

  17. [Euthanasia, assisted suicide, and the principle of double effect: a reply to Rodolfo Figueroa].

    PubMed

    Miranda, Alejandro M

    2012-02-01

    The purpose of this paper is to defend the traditional application of the principle of double effect as a criterion for assessing the permissibility of actions that have as their common aim to end the suffering of seriously ill patients. According to this principle, euthanasia and physician-assisted suicide are always illicit acts, while the same is not said for other actions that bring about patient's death as a foreseen effect, namely, palliative treatments that hasten death or failure or interruption of life support. The reason for this difference is that, in the first two cases, the patient's death is intended as a means of pain relief; whereas, in the latter two, death is only a side effect of a medical act, an act justifiable if it is necessary to achieve a proportionate good. In a recent issue of this Journal, Professor Rodolfo Figueroa denied the soundness of the principle of double effect and maintained that all actions described above should be considered equivalent in law enforcement. Here, the author presents a reply to that argument, and also offers a justification of the afore said principle's core, that is, the moral and legal relevance of the distinction between intended effects and foreseen side effects.

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

    SciTech Connect

    Kumar, P.; Kumar, P.; Zachariah, K.; Rai, G.P.; Vijayraghavan, R. )

    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. This may be attributed to immunotoxic effects of CN on T-cells mediated macrophage functions.

  19. Is the doctrine of double effect irrelevant in end-of-life decision making?

    PubMed

    Allmark, Peter; Cobb, Mark; Liddle, B Jane; Tod, Angela Mary

    2010-07-01

    In this paper, we consider three arguments for the irrelevance of the doctrine of double effect in end-of-life decision making. The third argument is our own and, to that extent, we seek to defend it. The first argument is that end-of-life decisions do not in fact shorten lives and that therefore there is no need for the doctrine in justification of these decisions. We reject this argument; some end-of-life decisions clearly shorten lives. The second is that the doctrine of double effect is not recognized in UK law (and similar jurisdictions); therefore, clinicians cannot use it as the basis for justification of their decisions. Against this we suggest that while the doctrine might have dubious legal grounds, it could be of relevance in some ways, e.g. in marking the boundary between acceptable and unacceptable practice in relation to the clinician's duty to relieve pain and suffering. The third is that the doctrine is irrelevant because it requires there to be a bad effect that needs justification. This is not the case in end-of-life care for patients diagnosed as dying. Here, bringing about a satisfactory dying process for a patient is a good effect, not a bad one. What matters is that patients die without pain and suffering. This marks a crucial departure from the double-effect doctrine; if the patient's death is not a bad effect then the doctrine is clearly irrelevant. A diagnosis of dying allows clinicians to focus on good dying and not to worry about whether their intervention affects the time of death. For a patient diagnosed as dying, time of death is rarely important. In our conclusion we suggest that acceptance of our argument might be problematic for opponents of physician-assisted death. We suggest one way in which these opponents might argue for a distinction between such practice and palliative care; this relies on the double-effect doctrine's distinction between foresight and intention.

  20. Effects of electron cyclotron current drive on the evolution of double tearing mode

    SciTech Connect

    Sun, Guanglan Dong, Chunying; Duan, Longfang

    2015-09-15

    The effects of electron cyclotron current drive (ECCD) on the double tearing mode (DTM) in slab geometry are investigated by using two-dimensional compressible magnetohydrodynamics equations. It is found that, mainly, the double tearing mode is suppressed by the emergence of the secondary island, due to the deposition of driven current on the X-point of magnetic island at one rational surface, which forms a new non-complete symmetric magnetic topology structure (defined as a non-complete symmetric structure, NSS). The effects of driven current with different parameters (magnitude, initial time of deposition, duration time, and location of deposition) on the evolution of DTM are analyzed elaborately. The optimal magnitude or optimal deposition duration of driven current is the one which makes the duration of NSS the longest, which depends on the mutual effect between ECCD and the background plasma. Moreover, driven current introduced at the early Sweet-Parker phase has the best suppression effect; and the optimal moment also exists, depending on the duration of the NSS. Finally, the effects varied by the driven current disposition location are studied. It is verified that the favorable location of driven current is the X-point which is completely different from the result of single tearing mode.

  1. Scale effect on wave propagation of double-walled carbon nanotubes with initial axial loading.

    PubMed

    Heireche, H; Tounsi, A; Benzair, A

    2008-05-01

    This paper studies the vibrational characteristics of double-walled carbon nanotubes (DWNTs) with initial stress using a nonlocal Euler-Bernoulli beam model. Both the effect of initial stress and the effect of small length scale are discussed in detail. The effect of van der Waals forces is incorporated in the formulation. The corresponding resonant vibrational characteristics are presented in detail; they are shown to be very different from those predicted by classical elasticity theory when nonlocal effects are significant. The influence of initial stress in carbon nanotubes on their flexural vibration modes is dependent on the tension or compression form of the initial stress. The investigation of the effects of initial stress on transverse wave propagation in carbon nanotubes may be used as a useful reference for the application and the design of nanoelectronic and nanodrive devices, nano-oscillators, and nanosensors, in which carbon nanotubes act as basic elements. PMID:21825699

  2. Effect of double-stranded DNA on electrical double layer structure at oxide/electrolyte interface in classical molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Maekawa, Yuki; Shibuta, Yasushi; Sakata, Toshiya

    2015-01-01

    The elucidation of the electrical double layer (EDL) structure including biomolecules is helpful in controlling biointerfacial functions in biosensing devices. In this study, the effect of double-stranded DNA (ds-DNA) on the EDL structure at the SiO2/NaClaq interface in a concentrated solution was investigated by classical molecular dynamics (MD) simulation. In 1.0 M NaClaq, negatively charged ds-DNA shielded electrically by cations did not affect the potential profile of the EDL structure. This finding indicates that the simulated bio-interfacial structure allows the detection of ionic charges adsorbed directly onto substrates in a concentrated solution regardless of the presence of shielded biomolecular charges.

  3. Dispersion of gold nanoclusters in TMBPA-polycarbonate by a combination of thermal embedding and vapour-induced crystallization

    NASA Astrophysics Data System (ADS)

    Kruse, J.; Dolgner, K.; Greve, H.; Zaporojtchenko, V.; Faupel, F.

    2006-12-01

    Gold nanoclusters can be dispersed into the surface of a bisphenol-A polycarbonate film by acetone vapour induced crystallization, an effect which has been demonstrated in a previous publication of our group. Gold nanoclusters were deposited by physical vapour deposition on an amorphous thin film of polycarbonate. After vapour induced crystallization these clusters were detected by depth profiling to be embedded into the surface, with a concentration maximum in a depth of approximately 100 nm. In this work, we replaced the BPA by the modified tetramethyl bisphenol-A polycarbonate, which shows a slower crystallization kinetics. A strong enhancement of the dispersion depth has been achieved by thermal pre-embedding of the clusters into the surface. Surface analysis by means of atomic force microscopy reflects the rearrangement of polymer material in the course of crystallization.

  4. Measurements of Isotopic Composition of Vapour on the Antarctic Plateau

    NASA Astrophysics Data System (ADS)

    Casado, M.; Landais, A.; Masson-Delmotte, V.; Genthon, C.; Prie, F.; Kerstel, E.; Kassi, S.; Arnaud, L.; Steen-Larsen, H. C.; Vignon, E.

    2015-12-01

    The oldest ice core records are obtained on the East Antarctic plateau. The composition in stable isotopes of water (δ18O, δD, δ17O) permits to reconstruct the past climatic conditions over the ice sheet and also at the evaporation source. Paleothermometer accuracy relies on good knowledge of processes affecting the isotopic composition of surface snow in Polar Regions. Both simple models such as Rayleigh distillation and global atmospheric models with isotopes provide good prediction of precipitation isotopic composition in East Antarctica but post deposition processes can alter isotopic composition on site, in particular exchanges with local vapour. To quantitatively interpret the isotopic composition of water archived in ice cores, it is thus essential to study the continuum water vapour - precipitation - surface snow - buried snow. While precipitation and snow sampling are routinely performed in Antarctica, climatic conditions in Concordia, very cold (-55°C in average) and very dry (less than 1000ppmv), impose difficult conditions to measure the water vapour isotopic composition. New developments in infrared spectroscopy enable now the measurement of isotopic composition in water vapour traces (down to 20ppmv). Here we present the results of a campaign of measurement of isotopic composition in Concordia in 2014/2015. Two infrared spectrometers have been deployed or the first time on top of the East Antarctic Plateau allowing a continuous vapour measurement for a month. Comparison of the results from infrared spectroscopy with cryogenic trapping validates the relevance of the method to measure isotopic composition in dry conditions. Identification of different behaviour of isotopic composition in the water vapour associated to turbulent or stratified regime indicates a strong impact of meteorological processes in local vapour/snow interaction.

  5. Water vapour in the atmosphere of a transiting extrasolar planet.

    PubMed

    Tinetti, Giovanna; Vidal-Madjar, Alfred; Liang, Mao-Chang; Beaulieu, Jean-Philippe; Yung, Yuk; Carey, Sean; Barber, Robert J; Tennyson, Jonathan; Ribas, Ignasi; Allard, Nicole; Ballester, Gilda E; Sing, David K; Selsis, Franck

    2007-07-12

    Water is predicted to be among the most abundant (if not the most abundant) molecular species after hydrogen in the atmospheres of close-in extrasolar giant planets ('hot Jupiters'). Several attempts have been made to detect water on such planets, but have either failed to find compelling evidence for it or led to claims that should be taken with caution. Here we report an analysis of recent observations of the hot Jupiter HD 189733b (ref. 6) taken during the transit, when the planet passed in front of its parent star. We find that absorption by water vapour is the most likely cause of the wavelength-dependent variations in the effective radius of the planet at the infrared wavelengths 3.6 mum, 5.8 mum (both ref. 7) and 8 mum (ref. 8). The larger effective radius observed at visible wavelengths may arise from either stellar variability or the presence of clouds/hazes. We explain the report of a non-detection of water on HD 189733b (ref. 4) as being a consequence of the nearly isothermal vertical profile of the planet's atmosphere.

  6. Classical Two-Slit Interference Effects in Double Photoionization of Molecular Hydrogen at High Energies

    NASA Astrophysics Data System (ADS)

    Horner, D. A.; Miyabe, S.; Rescigno, T. N.; McCurdy, C. W.; Morales, F.; Martín, F.

    2008-10-01

    Recent experiments on double photoionization of H2 with photon energies between 160 and 240 eV have revealed body-frame angular distributions that suggest classical two-slit interference effects may be present when one electron carries most of the available energy and the second electron is not observed. We report precise quantum mechanical calculations that reproduce the experimental findings. They reveal that the interpretation in terms of classical diffraction is only appropriate at substantially higher photon energies. At the energies considered in the experiment we offer an alternative explanation based on the mixing of two nondiffractive contributions by circularly polarized light.

  7. Effects of autoionizing states on two-photon double ionization of the H2 molecule

    NASA Astrophysics Data System (ADS)

    Guan, Xiaoxu; Bartschat, Klaus; Schneider, Barry I.; Koesterke, Lars

    2014-04-01

    Treating the effects of autoionizing intermediate states on two-photon double ionization (DI) of the H2 molecule using time-dependent laser pulses is a significant computational challenge. Relatively long exposure times are critical to understanding the dynamics. Using the fixed-nuclei approximation, we demonstrate how the doubly excited states enhance the angle-integrated generalized cross sections in H2, and how they affect the angular distribution pattern of the ejected electrons. As the energy approaches the threshold for sequential DI, there is a sharp rise in the cross section due to virtual sequential ionization.

  8. Classical two-slit interference effects in double photoionization of molecular hydrogen at high energies

    SciTech Connect

    Horner, Daniel A.; Miyabe, Shungo; Rescigno, Thomas N; McCurdy, C. William; Morales, Felipe; Martin, Fernando

    2008-07-06

    Recent experiments on double photoionization of H$_2$ with photon energies between 160 and 240 eV have revealed body-frame angular distributions that suggest classical two-slit interference effects may be present when one electron carries most of the available energy and the second electron is not observed. We report precise quantum mechanical calculations that reproduce the experimental findings. They reveal that the interpretation in terms of classical diffraction is only appropriate atsubstantially higher photon energies. At the energies considered in the experiment we offer an alternative explanation based on the mixing of two non-diffractive contributions by circularly polarized light.

  9. A pH sensor with a double-gate silicon nanowire field-effect transistor

    NASA Astrophysics Data System (ADS)

    Ahn, Jae-Hyuk; Kim, Jee-Yeon; Seol, Myeong-Lok; Baek, David J.; Guo, Zheng; Kim, Chang-Hoon; Choi, Sung-Jin; Choi, Yang-Kyu

    2013-02-01

    A pH sensor composed of a double-gate silicon nanowire field-effect transistor (DG Si-NW FET) is demonstrated. The proposed DG Si-NW FET allows the independent addressing of the gate voltage and hence improves the sensing capability through an application of asymmetric gate voltage between the two gates. One gate is a driving gate which controls the current flow, and the other is a supporting gate which amplifies the shift of the threshold voltage, which is a sensing metric, and which arises from changes in the pH. The pH signal is also amplified through modulation of the gate oxide thickness.

  10. Effect of beta on Seismic Vulnerability Curve for RC Bridge Based on Double Damage Criterion

    SciTech Connect

    Feng Qinghai; Yuan Wancheng

    2010-05-21

    In the analysis of seismic vulnerability curve based on double damage criterion, the randomness of structural parameter and randomness of seismic should be considered. Firstly, the distribution characteristics of structure capability and seismic demand are obtained based on IDA and PUSHOVER, secondly, the vulnerability of the bridge is gained based on ANN and MC and a vulnerability curve according to this bridge and seismic is drawn. Finally, the analysis for a continuous bridge is displayed as an example, and parametric analysis for the effect of beta is done, which reflects the bridge vulnerability overall from the point of total probability, and in order to reduce the discreteness, large value of beta are suggested.

  11. Numerical investigation of the escape factor of lithium and sodium vapour at partial frequency redistribution

    NASA Astrophysics Data System (ADS)

    Kosarev, N. I.

    2008-11-01

    The method of numerical simulation was used to study the effective lifetime of the excited level of the resonance transition in sodium and lithium vapour. Taking into account the partial frequency redistribution and the cylindrical geometry of the medium, the rate equations of the population balance of a two-level atom were solved with the equation of radiation transfer. The Biberman-Holstein escape factor was calculated as a function of the optical thickness of vapour for different geometries of the luminescing gas and different models of the frequency redistribution functions. The dependence of the escape factor on the optical thickness investigated experimentally by Romberg and Kunze (J. Quant. Spectrosc. Radiat. Transfer. 1988 39 99) is discussed.

  12. 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

  13. Localisation of an unknown number of land mines using a network of vapour detectors.

    PubMed

    Chhadé, Hiba Haj; Abdallah, Fahed; Mougharbel, Imad; Gning, Amadou; Julier, Simon; Mihaylova, Lyudmila

    2014-11-06

    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.

  14. Light induced chemical vapour deposition of titanium oxide thin films at room temperature

    NASA Astrophysics Data System (ADS)

    Halary, E.; Benvenuti, G.; Wagner, F.; Hoffmann, P.

    2000-02-01

    High resolution patterned deposition of titania is achieved by light induced chemical vapour deposition (LICVD), by imaging a mask onto a glass substrate. A long pulse XeCl Excimer laser (308 nm) provides, by perpendicular irradiation, the energy to convert titanium tetraisopropoxide (TTIP) vapour into titanium dioxide films, in an oxygen atmosphere, on unheated glass substrates. The amorphous titania deposits contain about 6% carbon contamination according to X-ray photoelectron spectroscopy (XPS) measurements. The deposition rate increases with increasing laser fluence until a maximum value is reached, then remains constant over a wide range, and finally decreases with further fluence increase due to titania ablation or thermal effects. The film thickness increases linearly with the number of pulses after a nucleation period. The strong influence of the laser pulse repetition rate on the growth rate and the thickness profile are reported.

  15. Chemical vapour deposition of thermochromic vanadium dioxide thin films for energy efficient glazing

    SciTech Connect

    Warwick, Michael E.A.; Binions, Russell

    2014-06-01

    Vanadium dioxide is a thermochromic material that undergoes a semiconductor to metal transitions at a critical temperature of 68 °C. This phase change from a low temperature monoclinic structure to a higher temperature rutile structure is accompanied by a marked change in infrared reflectivity and change in resistivity. This ability to have a temperature-modulated film that can limit solar heat gain makes vanadium dioxide an ideal candidate for thermochromic energy efficient glazing. In this review we detail the current challenges to such glazing becoming a commercial reality and describe the key chemical vapour deposition technologies being employed in the latest research. - Graphical abstract: Schematic demonstration of the effect of thermochromic glazing on solar radiation (red arrow represents IR radiation, black arrow represents all other solar radiation). - Highlights: • Vanadium dioxide thin films for energy efficient glazing. • Reviews chemical vapour deposition techniques. • Latest results for thin film deposition for vanadium dioxide.

  16. Noise spectrum of quantum transport through double quantum dots: Renormalization and non-Markovian effects

    NASA Astrophysics Data System (ADS)

    Shi, Pengqin; Hu, Menghan; Ying, Yaofeng; Jin, Jinshuang

    2016-09-01

    Based on the time-nonlocal particle number-resolved master equation, we investigate the sequential electron transport through the interacting double quantum dots. Our calculations show that there exists the effect of energy renormalization in the dispersion of the bath interaction spectrum and it is sensitive to the the bandwidth of the bath. This effect would strongly affect the stationary current and its zero-frequency shot noise for weak inter-dot coherent coupling strength, but for strong inter-dot coupling regime, it is negligible due to the strong intrinsic Rabi coherent dynamics. Moreover, the possible observable effects of the energy renormalization in the noise spectrum are also investigated through the Rabi coherence signal. Finally, the non-Markovian effect is manifested in the finite-frequency noise spectrum with the appearance of quasisteps, and the magnitude of these quasisteps are modified by the dispersion function.

  17. Experimental determination and theoretical framework of kinetic fractionation at the water vapour-ice interface at low temperature

    NASA Astrophysics Data System (ADS)

    Casado, Mathieu; Cauquoin, Alexandre; Landais, Amaelle; Israel, Dan; Orsi, Anaïs; Pangui, Edouard; Landsberg, Janek; Kerstel, Erik; Prie, Frederic; Doussin, Jean-François

    2016-02-01

    Water isotopes are commonly used for climate reconstruction from ice cores. The different heavy isotopes of water such as H218O, H217O or HDO give information about local temperature but also temperature and humidity of water vapour sources. Quantification of these parameters relies on the good knowledge of equilibrium and kinetic isotopic fractionation at each step of the water cycle. One of the strongest limitations when interpreting water isotopes in remote Antarctic ice cores is the formulation of the isotopic fractionation at solid condensation (vapour to ice). This classical formulation also implies a good knowledge of coefficients for equilibrium fractionation and water vapour diffusion in air as well as supersaturation in clouds. The uncertainties associated with these different parameters make the formulation of isotopic fractionation at solid condensation only empirical. Here, we make use (1) of recent development in the measurements of water isotopes in the water vapour through infra-red spectroscopy and (2) of the possibility to measure accurately 17O-excess of water to test the classical formulation and parameterization of isotopic fractionation at solid condensation. A first experiment involving very strong supersaturation evidences a strong kinetic effect on 17O-excess at solid condensation, similar to d-excess. It also shows the limits of the classical formulation of water isotopic fractionation during solid condensation estimation at very low temperature. A second experiment performed in a cloud chamber under controlled conditions uses cavity ring down spectrometers (CRDS) to determine the spatial variability of water vapour isotopic composition due to diffusion (kinetic effect) during solid condensation. The spatial variability of water vapour isotopic composition can be relatively well reproduced by the resolution of diffusion toward a cold plate. This preliminary study opens new perspectives to revisit the classical formulation of water isotopic

  18. Dynamics of Vapour Bubbles in Nucleate Boiling. 1; Basic Equations of Bubble Evolution

    NASA Technical Reports Server (NTRS)

    Buyevich, Yu A.; Webbon, Bruce W.; Callaway, Robert (Technical Monitor)

    1995-01-01

    We consider the behaviour of a vapour bubble formed at a nucleation site on a heated horizontal wall. There is no forced convection of an ambient liquid, and the bubble is presumably separated from the wall by a thin liquid microlayer. The energy conservation law results in a variational equation for the mechanical energy of the whole system consisting of the bubble and liquid. It leads to a set of two strongly nonlinear equations which govern bubble expansion and motion of its centre of mass. A supplementary equation to find out the vapour temperature follows from consideration of heat transfer to the bubble, both from the bulk of surrounding liquid and through the microlayer. The average thickness of the microlayer is shown to increase monotonously with time as the bubble meniscus spreads along the wall. Bubble expansion is driven by the pressure head between vapour inside and liquid far away from the bubble, with due allowance for surface tension and gravity effects. It is resisted by inertia of liquid being placed into motion as the bubble grows. The inertia originates also a force that presses the bubble to the wall. This force is counteracted by the buoyancy and an effective surface tension force that tends to transform the bubble into a sphere. The analysis brings about quite a new formulation of the familiar problem of bubble growth and detachment under conditions of nucleate pool boiling.

  19. Computational implementation of interfacial kinetic transport theory for water vapour transport in porous media.

    PubMed

    Albaalbaki, Bashar; Hill, Reghan J

    2014-01-01

    A computational framework is developed for applying interfacial kinetic transport theory to predict water vapour permeability of porous media. Modified conservation equations furnish spatially periodic disturbances from which the average flux and, thus, the effective diffusivity is obtained. The equations are solved exactly for a model porous medium comprising parallel layers of gas and solid with arbitrary solid volume fraction. From the microscale effective diffusivity, a two-point boundary-value problem is solved at the macroscale to furnish the water vapour transport rate in membranes subjected to a finite RH differential. Then, the microscale model is implemented using a computational framework (extended finite-element method) to examine the role of particle size, aspect ratio and positioning for periodic arrays of aligned super-ellipses (model particles that pack with high density). We show that the transverse water vapour permeability can be reduced by an order of magnitude only when fibres with a high-aspect ratio cross section are packed in a periodic staggered configuration. Maximum permeability is achieved at intermediate micro-structural length scales, where gas-phase diffusion is enhanced by surface diffusion, but not limited by interfacial-exchange kinetics. The two-dimensional computations demonstrated here are intended to motivate further efforts to develop efficient computational solutions for realistic three-dimensional microstructures.

  20. Aharonov-Bohm and Aharonov-Casher tunneling effects and edge states in double-barrier structures

    SciTech Connect

    Bogachek, E.N.; Landman, U. )

    1994-07-15

    The simultaneous occurrence of Aharonov-Bohm (AB) and Aharonov-Casher (AC) effects due to edge states in double-barrier two-dimensional wires formed by an electrostatic confinement potential, in the quantum Hall effect regime, is discussed. The AC effect is manifested via a shift of the AB conductance oscillations, and a method for measurement of the effect is proposed.

  1. 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. PMID:20576303

  2. 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.

  3. Vapour extraction (VAPEX) process for recovery of heavy oil and bitumen

    SciTech Connect

    Jha, K.N.; Butler, R.M.; Lim, G.B.

    1995-12-31

    For over 90% of the vast resources of bitumen and heavy oil in Canada, in situ recovery processes have to be developed to produce and utilize them efficiently and economically. Thermal recovery processes using steam, although effective for thick reservoirs with good quality sands, are increasingly proving to be uneconomical, particularly for thin, shaley, or bottom water reservoirs. The inefficiency is caused by large heat losses, high water requirement, extensive surface facilities, and adverse environmental impact. To overcome these problems, a new non-thermal vapour extraction (VAPEX) process has been developed. The process is closely related to the Steam-Assisted Gravity Drainage (SAGD) concept. However, in the VAPEX process the steam chamber is replaced with a chamber containing light hydrocarbon vapours close to its dew point at the reservoir pressure. If the pressure used is close to the saturation pressure of hydrocarbons, deasphalting may occur in the reservoir causing a substantial reduction in viscosity and heavy metal contents. Experiments conducted in a Hele-Shaw cell and in a 2D physical scaled model using Lloydminster, Cold Lake, and Peace River heavy oil/bitumen and ethane, propane, and butane as solvents demonstrated that this process is very promising technically as well as economically. An active aquifer underlying the bitumen zone made the reservoir more valuable because of spreading of the solvent vapour directly underneath the formation which increased the vapour-bitumen contact extensively. The investigation was extended from a dual horizontal continuous injection/production well strategy described above to a single horizontal well cyclic process for the Cold Lake reservoir in a 3D physical scaled model. The tests illustrated that ethane was an effective solvent in producing Cold Lake bitumen and that the cyclic VAPEX process has the potential to be a breakthrough recovery technology.

  4. An Examination of the Effects of Double-Strand Breaks on Extrachromosomal Recombination in Mammalian Cells

    PubMed Central

    Yang, D.; Waldman, A. S.

    1992-01-01

    We studied the effects of double-strand breaks on intramolecular extrachromosomal homologous recombination in mammalian cells. Pairs of defective herpes thymidine kinase (tk) sequences were introduced into mouse Ltk(-) cells on a DNA molecule that also contained a neo gene under control of the SV40 early promoter/enhancer. With the majority of the constructs used, gene conversions or double crossovers, but not single crossovers, were recoverable. DNA was linearized with various restriction enzymes prior to transfection. Recombination events producing a functional tk gene were monitored by selecting for tk-positive colonies. For double-strand breaks placed outside of the region of homology, maximal recombination frequencies were measured when a break placed the two tk sequences downstream from the SV40 early promoter/enhancer. We observed no relationship between recombination frequency and either the distance between a break and the tk sequences or the distance between the tk sequences. The quantitative effects of the breaks appeared to depend on the degree of homology between the tk sequences. We also observed that inverted repeats recombined as efficiently as direct repeats. The data indicated that the breaks influenced recombination indirectly, perhaps by affecting the binding of a factor(s) to the SV40 promoter region which in turn stimulated or inhibited recombination of the tk sequences. Taken together, we believe that our results provide strong evidence for the existence of a pathway for extrachromosomal homologous recombination in mammalian cells that is distinct from single-strand annealing. We discuss the possibility that intrachromosomal and extrachromosomal recombination have mechanisms in common. PMID:1459429

  5. Nanofluidic transport governed by the liquid/vapour interface

    NASA Astrophysics Data System (ADS)

    Lee, Jongho; Laoui, Tahar; Karnik, Rohit

    2014-04-01

    Liquid/vapour interfaces govern the behaviour of a wide range of systems but remain poorly understood, leaving ample margin for the exploitation of intriguing functionalities for applications. Here, we systematically investigate the role of liquid/vapour interfaces in the transport of water across apposing liquid menisci in osmosis membranes comprising short hydrophobic nanopores that separate two fluid reservoirs. We show experimentally that mass transport is limited by molecular reflection from the liquid/vapour interface below a certain length scale, which depends on the transmission probability of water molecules across the nanopores and on the condensation probability of a water molecule incident on the liquid surface. This fundamental yet elusive condensation property of water is measured under near-equilibrium conditions and found to decrease from 0.36 +/- 0.21 at 30 °C to 0.18 +/- 0.09 at 60 °C. These findings define the regime in which liquid/vapour interfaces govern nanofluidic transport and have implications for understanding mass transport in nanofluidic devices, droplets and bubbles, biological components and porous media involving liquid/vapour interfaces.

  6. Avalanche effect and bit independence behaviors of double random phase encoding schemes

    NASA Astrophysics Data System (ADS)

    Sultana, Nishat; Moon, Inkyu

    2016-06-01

    In this paper, we present an overview of the avalanche and bit independence characteristics of double random phase encoding (DRPE) scheme in the virtual optical domains. DRPE apparently demonstrates outstanding bit independence property in both the Fourier and Fresnel domains. Experimental results validate that the DRPE performance in Fresnel domain surpasses the DRPE in Fourier domain by showing better avalanche effect characteristics. The avalanche effect result is remarkably poor for the DRPE in Fourier domain when only one bit of the plaintext or encryption key is altered. In contrast, DRPE in Fresnel domain shows adequate avalanche effect results regardless of how many numbers of bits are altered in the plaintext or in the encryption key.

  7. Effect of nuclear radiation on the electrical properties of chemical double layer capacitors

    SciTech Connect

    Laghari, J.R. . Dept. of Electrical and Computer Engineering); Hammoud, A.N. . Lewis Research Center)

    1990-04-01

    The effects of nuclear radiation on the electrical properties of chemical double layer capacitors are determined. The capacitors were irradiated in a 2-MW nuclear reactor to different fluence levels. The exposure rate was 2.2 {times} 10{sup 10} n/cm{sup 2} {center dot} s of thermal neutrons, 9.52 {times} 10{sup 8} n/cm{sup 2} {center dot} s of fast neutrons (> 2 MeV), and 1.47 {times} 10{sup 6} rad/h of gamma radiation. The properties measured during and after irradiation included the capacitance, equivalent series resistance, and open-circuit voltage. The post-irradiation effect on the leakage current was also determined. It was found that while the capacitance increased during irradiation, the equivalent series resistance and the open-circuit voltage decreased slightly during irradiation. Changes in these properties were not permanent s was evident from post-irradiation measurements. The leakage current did not show any significant change with radiation. The results indicate that chemical double layer capacitors can be suitably used as backup power source in electronic equipment operating in a radiation environment with total fluences up to 4.05 {times} 10{sup 14} n/cm{sup 2}.

  8. Tar reduction in pyrolysis vapours from biomass over a hot char bed.

    PubMed

    Gilbert, P; Ryu, C; Sharifi, V; Swithenbank, J

    2009-12-01

    The behaviour of pyrolysis vapours over char was investigated in order to maximise tar conversion for the development of a new fixed bed gasifier. Wood samples were decomposed at a typical pyrolysis temperature (500 degrees C) and the pyrolysis vapours were then passed directly through a tar cracking zone in a tubular reactor. The product yields and properties of the condensable phases and non-condensable gases were studied for different bed lengths of char (0-450 mm), temperatures (500-800 degrees C), particle sizes (10 and 15 mm) and nitrogen purge rates (1.84-14.70 mm/s). The carbon in the condensable phases showed about 66% reduction by a 300 mm long char section at 800 degrees C, compared to that for pyrolysis at 500 degrees C. The amount of heavy condensable phase decreased with increasing temperature from about 18.4 wt% of the biomass input at 500 degrees C to 8.0 wt% at 800 degrees C, forming CO, H(2) and other light molecules. The main mode of tar conversion was found to be in the vapour phase when compared to the results without the presence of char. The composition of the heavy condensable phase was simplified into much fewer secondary and tertiary tar components at 800 degrees C. Additional measures were required to maximise the heterogeneous effect of char for tar reduction. PMID:19604685

  9. Randomized double-blind comparison of cognitive and EEG effects of lacosamide and carbamazepine.

    PubMed

    Meador, Kimford J; Loring, David W; Boyd, Alan; Echauz, Javier; LaRoche, Suzette; Velez-Ruiz, Naymee; Korb, Pearce; Byrnes, William; Dilley, Deanne; Borghs, Simon; De Backer, Marc; Story, Tyler; Dedeken, Peter; Webster, Elizabeth

    2016-09-01

    Differential effectiveness of antiepileptic drugs (AEDs) is more commonly determined by tolerability than efficacy. Cognitive effects of AEDs can adversely affect tolerability and quality of life. This study evaluated cognitive and EEG effects of lacosamide (LCM) compared with carbamazepine immediate-release (CBZ-IR). A randomized, double-blind, double-dummy, two-period crossover, fixed-dose study in healthy subjects compared neuropsychological and EEG effects of LCM (150mg, b.i.d.) and CBZ-IR (200mg, t.i.d.). Testing was conducted at screening, predrug baseline, the end of each treatment period (3-week titration; 3-week maintenance), and the end of each washout period (4weeks after treatment). A composite Z-score was derived for the primary outcome variable (computerized cognitive tests and traditional neuropsychological measures) and separately for the EEG measures. Other variables included individual computer, neuropsychological, and EEG scores and adverse events (AEs). Subjects included 60 healthy adults (57% female; mean age: 34.4years [SD: 10.5]); 44 completed both treatments; 41 were per protocol subjects. Carbamazepine immediate-release had worse scores compared with LCM for the primary composite neuropsychological outcome (mean difference=0.33 [SD: 1.36], p=0.011) and for the composite EEG score (mean difference=0.92 [SD: 1.77], p=0.003). Secondary analyses across the individual variables revealed that CBZ-IR was statistically worse than LCM on 36% (4/11) of the neuropsychological tests (computerized and noncomputerized) and 0% of the four EEG measures; none favored CBZ-IR. Drug-related AEs occurred more with CBZ-IR (49%) than LCM (22%). Lacosamide had fewer untoward neuropsychological and EEG effects and fewer AEs and AE-related discontinuations than CBZ-IR in healthy subjects. Lacosamide exhibits a favorable cognitive profile. PMID:27517350

  10. CO2-fluxing collapses metal mobility in magmatic vapour

    DOE PAGES

    van Hinsberg, V. J.; Berlo, K.; Migdisov, A. A.; Williams-Jones, A. E.

    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 CO2-rich vapour exsolved from deeper magma is now recognised as ubiquitous during open-system magma degassing. Furthermore, we show that such CO2-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 mechanism for metalmore » deposition.« less

  11. 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. PMID:25498927

  12. 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.

  13. Bi-fluid and neoclassical effect on a Double-Tearing mode in Tore Supra

    SciTech Connect

    Maget, Patrick Garbet, Xavier; Février, Olivier; Ségui, Jean-Luc; Lütjens, Hinrich; Luciani, Jean-François

    2014-06-15

    Tearing modes associated to hollow current profiles are prone to grow in moderate performance plasmas and often constrain the realization of non-inductive discharges in the Tore Supra tokamak, where long pulse duration is performed using Lower Hybrid waves for providing most of the plasma current. The prediction of MHD boundaries in such scenarios is complicated by the importance of diamagnetic effects, combined with curvature stabilization, which determine the stability of these modes. We show that diamagnetic effects, as well as neoclassical forces, are playing a key role in the linear and nonlinear regimes of Double-Tearing Modes on q = 5/3 and q = 2 in these experimental conditions. Detailed comparison with experimental measurements, combined with a scaling in plasma resistivity, give constraints about the experimental equilibrium. Resistive-Interchange Modes destabilized by diamagnetic rotation could also play a role in degrading the energy confinement in the negative magnetic shear region.

  14. The effects of mesterolone, a male sex hormone in depressed patients (a double blind controlled study).

    PubMed

    Itil, T M; Michael, S T; Shapiro, D M; Itil, K Z

    1984-06-01

    Based on computer EEG (CEEG) profiles, in high doses, antidepressant properties of mesterolone, a synthetic androgen, were predicted. In a double-blind placebo controlled study, the clinical effects of 300-450 mg daily mesterolone were investigated in 52 relatively young (age range 26-53 years, mean 42.7 years) male depressed outpatients. During 6 weeks of mesterolone treatment, there was a significant improvement of depressive symptomatology. However, since an improvement was also established during the placebo treatment, no statistically appreciable difference in the therapeutic effects of mesterolone was established compared to placebo. Mesterolone treatment significantly decreased both plasma testosterone and protein bound testosterone levels. Patients with high testosterone levels prior to treatment seem to have had more benefit from mesterolone treatment than patients with low testosterone levels. The degree of improvement weakly correlated to the decrease of testosterone levels during mesterolone treatment. PMID:6431212

  15. The effects of mesterolone, a male sex hormone in depressed patients (a double blind controlled study).

    PubMed

    Itil, T M; Michael, S T; Shapiro, D M; Itil, K Z

    1984-06-01

    Based on computer EEG (CEEG) profiles, in high doses, antidepressant properties of mesterolone, a synthetic androgen, were predicted. In a double-blind placebo controlled study, the clinical effects of 300-450 mg daily mesterolone were investigated in 52 relatively young (age range 26-53 years, mean 42.7 years) male depressed outpatients. During 6 weeks of mesterolone treatment, there was a significant improvement of depressive symptomatology. However, since an improvement was also established during the placebo treatment, no statistically appreciable difference in the therapeutic effects of mesterolone was established compared to placebo. Mesterolone treatment significantly decreased both plasma testosterone and protein bound testosterone levels. Patients with high testosterone levels prior to treatment seem to have had more benefit from mesterolone treatment than patients with low testosterone levels. The degree of improvement weakly correlated to the decrease of testosterone levels during mesterolone treatment.

  16. The Primary Electroviscous Effect: Thin Double Layers (akappa>1) and a Stern Layer.

    PubMed

    Sherwood; Rubio-Hernández; Ruiz-Reina

    2000-08-01

    The primary electroviscous effect due to the charge clouds surrounding spherical charged particles suspended in an electrolyte was studied by Hinch and Sherwood (J. Fluid Mech. 132, 337 (1983)) in the limit of double layers thin compared to the particle radius a. Here we introduce the effect of a dynamic Stern layer into that analysis, in order to explain the numerical results of Rubio-Hernández et al. (J. Colloid Interface Sci. 206, 334 (1998)) in terms of the ratio of the tangential ionic fluxes within the charge cloud to those within the Stern layer. The predictions of the asymptotic analysis are compared with those of numerical computations. The thickness of the charge cloud is characterized by the Debye length kappa(-1). If akappa>10 the predictions of the asymptotic analysis exhibit the same qualitative behavior as the numerical results, but akappa>1000 is required to achieve quantitative agreement to within 2.5%. Copyright 2000 Academic Press.

  17. Substituent effects in double-helical hydrogen-bonded AAA-DDD complexes.

    PubMed

    Wang, Hong-Bo; Mudraboyina, Bhanu P; Wisner, James A

    2012-01-27

    Two series of DDD and AAA hydrogen-bond arrays were synthesized that form triply-hydrogen-bonded double-helical complexes when combined in CDCl(3) solution. Derivatization of the DDD arrays with electron-withdrawing groups increases the complex association constants by up to a factor of 30 in those arrays examined. Derivatization of the AAA arrays with electron donating substituents reveals a similar magnitude effect on the complex stabilities. The effect of substitution on both types of arrays are modeled quite satisfactorily (R(2) > 0.96 in all cases) as free energy relationships with respect to the sums of their Hammett substituent constants. In all, the complex stabilities can be manipulated over more than three orders of magnitude (>20 kJ mol(-1)) using this type of modification.

  18. Effects of Atorvastatin on Negative Sign in Chronic Schizophrenia: a Double Blind Clinical Trial

    PubMed Central

    Sayyah, Mehdi; Boostani, Hatam; Ashrafpoori, Mitra; Pakseresht, Siroos

    2015-01-01

    The aim of this study was to evaluate the effects of Atorvastatin on negative symptoms in patients with chronic schizophrenia. The study was a prospective, double-blind, 6-week trial. Forty patients participated in the study; 19 patients were assigned to the Atorvastatin group as well as 21 patients to the placebo group. For assessing negative signs, we used Scale for the Assessment of Negative Symptoms (SANS) in weeks 1st, 3nd, 4th, and 6th. Moreover, patients were randomly assigned to treatment groups with Risperidone (6 mg/day) plus 20 mg Atorvastatin or with Risperidone (6 mg/day) plus placebo. Mean scores of Scale for the Assessment of Negative Symptoms (SANS) decreased during the treatment but there was no significant difference between the mean scores of two groups. The result of this trial suggested that Atorvastatin can be effective in reducing negative sign in schizophrenia although further studies seem to be needed. PMID:26664396

  19. LSS 2018: A double-lined spectroscopic binary central star with an extremely large reflection effect

    NASA Technical Reports Server (NTRS)

    Drilling, J. S.

    1985-01-01

    LSS 2018, the central star of the planetry nebulae DS1, was found to be a double-lined spectroscopic binary with a period of 8.571 hours. Light variations with the same period were observed in U, B, and V; in the wavelength regions defined by the two IUE cameras; and in the strength of the CIII 4647 emission line. The light variations can be accurately predicted by a simple reflection effect, and an analysis of the light curves yields the angular diameter and effective temperature of the primary, the radii of the two stars in terms of their separation, and the inclination of the system. Analysis of the radial velocities then yields the masses of the two stars, their separation, the distance of the system, the absolute magnitude of the primary, and the size of the nebula.

  20. LSS 2018 - A double-lined spectroscopic binary central star with an extremely large reflection effect

    NASA Technical Reports Server (NTRS)

    Drilling, J. S.

    1985-01-01

    LSS 2018, the central star of the planetary nebulae DS1, was found to be a double-lined spectroscopic binary with a period of 8.571 hours. Light variations with the same period were observed in U, B, and V; in the wavelength regions defined by the two IUE cameras; and in the strength of the CIII 4647 emission line. The light variations can be accurately predicted by a simple reflection effect, and an analysis of the light curves yields the angular diameter and effective temperature of the primary, the radii of the two stars in terms of their separation, and the inclination of the system. Analysis of the radial velocities then yields the masses of the two stars, their separation, the distance of the system, the absolute magnitude of the primary, and the size of the nebula.

  1. Proximity-induced superconductivity effect in a double-stranded DNA

    SciTech Connect

    Simchi, Hamidreza; Esmaeilzadeh, Mahdi Mazidabadi, Hossein

    2014-02-07

    We study the proximity-induced superconductivity effect in a double-stranded DNA by solving the Bogoliubov-de Gennes equations and taking into account the effect of thermal fluctuations of the twist angle between neighboring base pairs. We show that the electron conductance is spin-dependent and the conductance of spin up (down) increases (decreases) due to the spin-orbit coupling (SOC). It is found that, for T < 100 K, the band gap energy is temperature-independent and it decreases due to the SOC. In addition, by solving the Bogoliubov-de Gennes equations and local gap parameter equation self-consistently, we find the critical temperature at which transition to superconductivity can take place.

  2. Giant Magnetocaloric Effect in the Double-perovskite Gd2 NiMnO6

    NASA Astrophysics Data System (ADS)

    Moon, Jae Young; Kim, Mi Kyung; Oh, Dong Kun; Oh, Sang Hyup; Lee, Nara; Choi, Young Jai

    We have synthesized single crystal of Gd2NiMnO6(GNMO) by the Bi-flux method and investigated magnetocaloric effect in them by magnetic measurements. Magnetic susceptibility of GNMO increases smoothly as temperature decrease and ferromagnetic order occurs below 135 K, and additional anomaly show at low temperature, indicative of the onset of Gd3+ spin arrangement. At the temperature, magnetic entropy change, - ΔSM, with the field changes of 0-9 T, calculated from isothermal M(H) data using Maxwell relation, exhibits sharp peak. This peak is gigantic and cryogenic, these make GNMO promising cryogenic magnetic refrigerant materials. Giant Magnetocaloric Effect in the Double-perovskite Gd2 NiMnO6 .

  3. Comparison of radiative and physiological effects of doubled atmospheric CO{sub 2} on climate

    SciTech Connect

    Sellers, P.J.; Collatz, G.J.; Los, S.O.

    1996-03-08

    The physiological response of terrestrial vegetation when directly exposed to an increase in atmospheric carbon dioxide (CO{sub 2}) concentration could result in warming over the continents in addition to that due to the conventional CO{sub 2} {open_quotes}greenhouse effect.{close_quotes} Results from a coupled biosphere-atmosphere model (SiB2-GCM) indicate that, for doubled CO{sub 2} conditions, evapotranspiration will drop and air temperature will increase over the tropical continents, amplifying the changes resulting from atmospheric radiative effects. The range of responses in surface air temperature and terrestrial carbon uptake due to increased CO{sub 2} are projected to be inversely related in the tropics year-round and inversely related during the growing season elsewhere. 21 refs., 4 figs., 2 tabs.

  4. Variability of winter-time middle atmospheric water vapour over the Arctic as observed with a ground-based microwave radiometer

    NASA Astrophysics Data System (ADS)

    Tschanz, Brigitte; Kivi, Rigel; Rüfenacht, Rolf; Kämpfer, Niklaus

    2014-05-01

    Middle atmospheric water vapour has a long chemical lifetime and can therefore be used as a tracer for dynamics. The ground-based microwave radiometer MIAWARA-C is designed for the use on campaigns and measures profiles of water vapour in the upper stratosphere and mesosphere and thus provides valuable data for the investigation of atmospheric processes. It has been operational for five years and has successfully participated in measurement campaigns under various climatic conditions in Germany, Switzerland, California, Finland and on la Réunion. The temporal resolution of the obtained water vapour profiles approximately 2 hours depending on tropospheric conditions. During two campaigns from January to June 2010 and from July 2011 to April 2013 in Sodankylä, Finland, MIAWARA-C monitored time series of polar middle atmospheric water vapour for three winters with three Sudden Stratospheric Warmings (SSW) occurring in early 2010, 2012 and 2013. The obtained time series are used to study the effects of the three SSWs on middle-atmospheric water vapour. During an SSW, humid mid- to low-latitude air is transported towards the polar region resulting in a fast increase in water vapour. The descent of water vapour after the SSW allows the estimation of the descent rate over the polar region as the normal wintertime circulation reforms. Results from the three SSWs are compared. The ground-based water vapour data is combined with sonde data of the Finnish Meteorological Institute and ground-based microwave wind measurements for one winter in order to obtain a more complete picture of the dynamics in the polar winter atmosphere.

  5. The Role of Water Vapour in Earth's Energy Flows

    NASA Astrophysics Data System (ADS)

    Allan, Richard P.

    2012-07-01

    Water vapour modulates energy flows in Earth's climate system through transfer of latent heat by evaporation and condensation and by modifying the flows of radiative energy both in the longwave and shortwave portions of the electromagnetic spectrum. This article summarizes the role of water vapour in Earth's energy flows with particular emphasis on (1) the powerful thermodynamic constraint of the Clausius Clapeyron equation, (2) dynamical controls on humidity above the boundary layer (or free-troposphere), (3) uncertainty in continuum absorption in the relatively transparent "window" regions of the radiative spectrum and (4) implications for changes in the atmospheric hydrological cycle.

  6. Spontaneuos and Parametric Processes in Warm Rubidium Vapours

    NASA Astrophysics Data System (ADS)

    Dąbrowski, M.; Parniak, M.; Pęcak, D.; Chrapkiewicz, R.; Wasilewski, W.

    2014-12-01

    Warm rubidium vapours are known to be a versatile medium for a variety of experiments in atomic physics and quantum optics. Here we present experimental results on producing the frequency converted light for quantum applications based on spontaneous and stimulated processes in rubidium vapours. In particular, we study the efficiency of spontaneously initiated stimulated Raman scattering in the Λ-level configuration and conditions of generating the coherent blue light assisted by multi-photon transitions in the diamond-level configuration. Our results will be helpful in search for new types of interfaces between light and atomic quantum memories.

  7. Reduction of skin effect losses in double-level-T-gate structure

    SciTech Connect

    Mikulics, M. Hardtdegen, H.; Arango, Y. C.; Adam, R.; Fox, A.; Grützmacher, D.; Gregušová, D.; Novák, J.; Stanček, S.; Kordoš, P.; Sofer, Z.; Juul, L.; Marso, M.

    2014-12-08

    We developed a T-gate technology based on selective wet etching yielding 200 nm wide T-gate structures used for fabrication of High Electron Mobility Transistors (HEMT). Major advantages of our process are the use of only standard photolithographic process and the ability to generate T-gate stacks. A HEMT fabricated on AlGaN/GaN/sapphire with gate length L{sub g} = 200 nm and double-stacked T-gates exhibits 60 GHz cutoff frequency showing ten-fold improvement compared to 6 GHz for the same device with 2 μm gate length. HEMTs with a double-level-T-gate (DLTG) structure exhibit up to 35% improvement of f{sub max} value compared to a single T-gate device. This indicates a significant reduction of skin effect losses in DLTG structure compared to its standard T-gate counterpart. These results agree with the theoretical predictions.

  8. Decisions that hasten death: double effect and the experiences of physicians in Australia

    PubMed Central

    2014-01-01

    Background In Australian end-of-life care, practicing euthanasia or physician-assisted suicide is illegal. Despite this, death hastening practices are common across medical settings. Practices can be clandestine or overt but in many instances physicians are forced to seek protection behind ambiguous medico-legal imperatives such as the Principle of Double Effect. Moreover, the way they conceptualise and experience such practices is inconsistent. To complement the available statistical data, the purpose of this study was to understand the reasoning behind how and why physicians in Australia will hasten death. Method A qualitative investigation was focused on palliative and critical/acute settings. A thematic analysis was conducted on semi-structured in-depth interviews with 13 specialist physicians. Attention was given to eliciting meanings and experiences in Australian end-of-life care. Results Highlighting the importance of a multidimensional approach, physicians negotiated multiple influences when death was regarded as hastened. The way they understood and experienced end-of-life care practices were affected by politico-religious and cultural influences, medico-legal imperatives, and personal values and beliefs. Interpersonal and intrapsychic aspects further emphasised the emotional and psychological investment physicians have with patients and others. In most cases death occurred as a result of treating suffering, and sometimes to fulfil the wishes of patients and others who requested death. Experience was especially subject to the efficacy with which physicians negotiated complex but context-specific situations, and was reflective of how they considered a good death. Although many were compelled to draw on the Principle of Double Effect, every physician reported its inadequacy as a medico-legal guideline. Conclusions The Principle of Double Effect, as a simplistic and generalised guideline, was identified as a convenient mechanism to protect physicians who

  9. Chromosome doubling method

    DOEpatents

    Kato, Akio

    2006-11-14

    The invention provides methods for chromosome doubling in plants. The technique overcomes the low yields of doubled progeny associated with the use of prior techniques for doubling chromosomes in plants such as grasses. The technique can be used in large scale applications and has been demonstrated to be highly effective in maize. Following treatment in accordance with the invention, plants remain amenable to self fertilization, thereby allowing the efficient isolation of doubled progeny plants.

  10. Cost-effectiveness and clinical outcomes of double versus single cord blood transplantation in adults with acute leukemia in France

    PubMed Central

    Labopin, Myriam; Ruggeri, Annalisa; Gorin, Norbert Claude; Gluckman, Eliane; Blaise, Didier; Mannone, Lionel; Milpied, Noel; Yakoub-Agha, Ibrahim; Deconinck, Eric; Michallet, Mauricette; Fegueux, Nathalie; Socié, Gerard; Nguyen, Stephanie; Cahn, Jean Yves; de Revel, Thierry; Garnier, Federico; Faucher, Catherine; Taright, Namik; Kenzey, Chantal; Volt, Fernanda; Bertrand, Dominique; Mohty, Mohamad; Rocha, Vanderson

    2014-01-01

    Double cord blood transplantation extends the use of cord blood to adults for whom a single unit is not available, but the procedure is limited by its cost. To evaluate outcomes and cost-effectiveness of double compared to single cord blood transplantation, we analyzed 134 transplants in adults with acute leukemia in first remission. Transplants were performed in France with reduced intensity or myeloablative conditioning regimens. Costs were estimated from donor search to 1 year after transplantation. A Markov decision analysis model was used to calculate quality-adjusted life-years and cost-effectiveness ratio within 4 years. The overall survival at 2 years after single and double cord blood transplants was 42% versus 62%, respectively (P=0.03), while the leukemia-free-survival was 33% versus 53%, respectively (P=0.03). The relapse rate was 21% after double transplants and 42% after a single transplant (P=0.006). No difference was observed for non-relapse mortality or chronic graft-versus-host-disease. The estimated costs up to 1 year after reduced intensity conditioning for single and double cord blood transplantation were € 165,253 and €191,827, respectively. The corresponding costs after myeloablative conditioning were € 192,566 and € 213,050, respectively. Compared to single transplants, double cord blood transplantation was associated with supplementary costs of € 21,302 and € 32,420 up to 4 years, but with increases in quality-adjusted life-years of 0.616 and 0.484, respectively, and incremental cost-effectiveness ratios of € 34,581 and €66,983 in the myeloablative and reduced intensity conditioning settings, respectively. Our results showed that for adults with acute leukemia in first complete remission in France, double cord transplantation is more cost-effective than single cord blood transplantation, with better outcomes, including quality-adjusted life-years. PMID:24143000

  11. Effective Bolus Dose of Sufentanil to Attenuate Cardiovascular Responses in Laryngoscopic Double-Lumen Endobronchial Intubation

    PubMed Central

    Choi, Byung-Hee; Lee, Yong-Cheol

    2016-01-01

    Background Sufentanil is a potent opioid analgesic frequently used in clinical anesthesia. Double-lumen endobronchial intubation induces profound cardiovascular responses in comparison with ordinary endotracheal intubation because of the larger tube diameter and direct irritation of the carina. Objectives The purpose of this study was to determine the effective bolus dose of sufentanil to attenuate hemodynamic changes in response to laryngoscopic double-lumen endobronchial intubation. Patients and Methods We randomly assigned 72 patients aged 18 - 65 years and with an American Society of Anesthesiologists physical status of 1 or 2 to one of four sufentanil dose groups: NS, S0.1, S0.2, or S0.3. The respective doses for the groups were as follows: normal saline, 0.1 mcg/kg of sufentanil, 0.2 mcg/kg of sufentanil, and 0.3 mcg/kg of sufentanil. Blood pressure and heart rate were recorded during the pre-anesthesia period at baseline, pre-intubation, immediate post-intubation, and every minute during 5 minutes after intubation. Results Baseline mean arterial pressures in the NS, S0.1, S0.2, and S0.3 groups were 89.8 ± 12.1, 89.2 ± 10.9, 88.8 ± 13.6, and 90.7 ± 11.1, respectively. At immediate post-intubation, the mean arterial pressures in the NS, S0.1, S0.2, and S0.3 groups were 129.7 ± 14.7, 120.7 ± 14.2, 120.8 ± 17.2, and 96.7 ± 10.4, respectively. At immediate post-intubation, the mean arterial pressure in the NS, S0.1, and S0.2 groups significantly increased from baseline (P < 0.001), but the S0.3 group showed no difference. In the time point comparison at immediate post- intubation, the S0.3 group had a significantly lower mean arterial pressure than did the NS, S0.1, and S0.2 groups (P < 0.001). Conclusions We found that 0.3 mcg/kg of sufentanil attenuates cardiovascular responses to double-lumen endobronchial intubation without adverse effects. PMID:27252903

  12. Resonance effects in two-photon double ionization of H2 by femtosecond XUV laser pulses

    NASA Astrophysics Data System (ADS)

    Guan, Xiaoxu; Bartschat, Klaus; Schneider, Barry I.; Koesterke, Lars

    2013-10-01

    We investigate the effect of the pulse length on the two-photon double ionization (DI) of H2 in the direct domain, for a femtosecond (fs) laser with a polarization vector oriented along the molecular axis. In the fixed-nuclei approximation, we find that the doubly excited Q11Σu+ states manifest themselves as resonances in the angle-integrated cross sections if the laser interaction lasts longer than about 3 fs. Decay into single-ionization channels does not significantly affect the shape of the angular distribution. A sharp rise in the probability for DI, due to virtual sequential ionization, occurs when the photon energy approaches the threshold for sequential DI.

  13. Effect of spin exchange interaction on shot noise and tunnel magnetoresistance in double quantum dots

    NASA Astrophysics Data System (ADS)

    Xue, N. T.; Xie, H. Q.; Xue, H. B.; Liang, J.-Q.

    2014-05-01

    By means of the Rate equation approach in sequential tunneling regime, we study spin-polarized transport through series double quantum dots (DQD) weakly coupled to collinear ferromagnetic leads with particular attention on the effect of interdot spin exchange interaction (SEI). For the asymmetric DQD giant negative differential conductance is realized, which depends on the energy-level spacing between two dots. It is demonstrated that the voltage dependencies of the tunnel magnetoresistance (TMR) and the shot noise are sensitive to the SEI, which leads to the additional imbalance between spin-polarized currents. The super-Poissonian statistics is enhanced in the parallel leads’ configuration by the ferromagnetic SEI, which favorites the spin bunching, while it is suppressed by stronger antiferromagnetic SEI in antiparallel configuration for a symmetric DQD. The voltage dependencies of the TMR and shot noise may be used to probe the SEI.

  14. Statistical examination of laser therapy effects in controlled double-blind clinical trial

    NASA Astrophysics Data System (ADS)

    Boerner, Ewa; Podbielska, Halina

    2001-10-01

    For the evaluation of the therapy effects the double-blind clinical trial followed by statistical analysis was performed. After statistical calculations it was stated that laser therapy with IR radiation has a significant influence on the decrease of the level of pain in the examined group of patients suffering from various locomotive diseases. The level of pain of patients undergoing laser therapy was statistically lower than the level of pain of patients undergoing placebo therapy. It means that laser therapy had statistically significant influence on the decrease of the level of pain. The same tests were performed for evaluation of movement range. Although placebo therapy contributes to the increase of the range of movement, the statistically significant influence was stated in case of the therapeutic group treated by laser.

  15. Beaded nanofibers assembled from double-hydrophobic elastin-like block polypeptides: Effects of trifluoroethanol.

    PubMed

    Le, Duc H T; Okubo, Tatsuya; Sugawara-Narutaki, Ayae

    2015-03-01

    A "double-hydrophobic" elastin-like triblock polypeptide GPG has been constructed by mimicking the localization of proline- and glycine-rich hydrophobic domains of native elastin, a protein that provides elasticity and resilience to connective tissues. In this study, the effects of trifluoroethanol (TFE), an organic solvent that strongly affects secondary structures of polypeptides on self-assembly of GPG in aqueous solutions were systematically studied. Beaded nanofiber formation of GPG, where nanoparticles are initially formed by coacervation of the polypeptides followed by their connection into one-dimensional nanostructures, is accelerated by the addition of TFE at the concentrations up to 30% (v/v), whereas aggregates of nanoparticles are formed at 60% TFE. The concentration-dependent assembly pattern discussed is based on the influence of TFE on the secondary structures of GPG. Well-defined nanofibers whose diameter and secondary structures are controlled by TFE concentration may be ideal building blocks for constructing bioelastic materials in tissue engineering.

  16. Effect of double air injection on performance characteristics of centrifugal compressor

    NASA Astrophysics Data System (ADS)

    Hirano, Toshiyuki; Takano, Mizuki; Tsujita, Hoshio

    2015-02-01

    In the operation of a centrifugal compressor of turbocharger, instability phenomena such as rotating stall and surge are induced at a lower flow rate close to the maximum pressure ratio. In this study, for the suppression of surge phenomenon resulting in the extension of the stable operating range of centrifugal compressor to lower flow rate, the compressed air at the compressor exit was re-circulated and injected into the impeller inlet by using the double injection nozzle system. The experiments were performed to find out the optimum circumferential position of the second nozzle relative to the fixed first one and the optimum inner diameter of the injection nozzles, which are able to most effectively reduce the flow rate of surge inception. Moreover, in order to examine the universality of these optimum values, the experiments were carried out for two types of compressors.

  17. Thickness effects on the Coulomb drag rate in double quantum layer systems

    NASA Astrophysics Data System (ADS)

    Vazifehshenas, T.; Eskourchi, A.

    2007-02-01

    In this paper, we have investigated the effect of quantum layer thickness on Coulomb drag phenomenon in a double quantum well (DQW) system, in which the electrons momentum can transfer from one layer to another. We have applied the full random phase approximation (RPA) in dynamical dielectric matrix of this coupled two-dimensional electron gas (2DEG) system in order to obtain an improved result for temperature-dependent rate of momentum transfer. We have calculated the drag rate transresistivity for various well thicknesses at low and intermediate temperatures in Fermi-scale and for different electron gas densities. It has been obtained that the Coulomb drag rate increases with increasing the well width when the separation between the wells remains unchanged.

  18. Effects of T-tabs and large deflections in double cantilever beam specimen tests

    NASA Technical Reports Server (NTRS)

    Naik, Rajiv A.; Crews, John H., Jr.; Shivakumar, Kunigal N.

    1991-01-01

    A simple strength of materials analysis was developed for a double-cantilever beam (DCB) specimen to account for geometric nonlinearity effects due to large deflections and T-tabs. A new DCB data analysis procedure was developed to include the effects of these nonlinearities. The results of the analysis were evaluated by DCB tests performed for materials having a wide range of toughnesses. The materials used in the present study were T300/5208, IM7/8551-7, and AS4/PEEK. Based on the present analysis, for a typical deflection/crack length ratio of 0.3 (for AS4/PEEK), T-tabs and large deflections cause a 15 and 3 percent error, respectively, in the computer Mode I strain energy release rate. Design guidelines for DCB specimen thickness and T-tab height were also developed in order to keep errors due to these nonlinearities within 2 percent. Based on the test results, for both hinged and tabbed specimens, the effects of large deflection on the Mode I fracture toughness (G sub Ic) were almost negligible (less than 1 percent) in the case of T300/5208 and IM7/8551-7; however, AS4/PEEK showed a 2 to 3 percent effect. The effects of T-tabs G sub Ic were more significant for all the materials with T300/5208 showing a 5 percent error, IM7/8551-7 a 15 percent error, and, AS4/PEEK a 20 percent error.

  19. Effects of T-tabs and large deflections in double cantilever beam specimen tests

    NASA Astrophysics Data System (ADS)

    Naik, Rajiv A.; Crews, John H., Jr.; Shivakumar, Kunigal N.

    A simple strength of materials analysis was developed for a double-cantilever beam (DCB) specimen to account for geometric nonlinearity effects due to large deflections and T-tabs. A new DCB data analysis procedure was developed to include the effects of these nonlinearities. The results of the analysis were evaluated by DCB tests performed for materials having a wide range of toughnesses. The materials used in the present study were T300/5208, IM7/8551-7, and AS4/PEEK. Based on the present analysis, for a typical deflection/crack length ratio of 0.3 (for AS4/PEEK), T-tabs and large deflections cause a 15 and 3 percent error, respectively, in the computer Mode I strain energy release rate. Design guidelines for DCB specimen thickness and T-tab height were also developed in order to keep errors due to these nonlinearities within 2 percent. Based on the test results, for both hinged and tabbed specimens, the effects of large deflection on the Mode I fracture toughness (G sub Ic) were almost negligible (less than 1 percent) in the case of T300/5208 and IM7/8551-7; however, AS4/PEEK showed a 2 to 3 percent effect. The effects of T-tabs G sub Ic were more significant for all the materials with T300/5208 showing a 5 percent error, IM7/8551-7 a 15 percent error, and, AS4/PEEK a 20 percent error.

  20. Photovoltaic and photothermoelectric effect in a double-gated WSe2 device.

    PubMed

    Groenendijk, Dirk J; Buscema, Michele; Steele, Gary A; Michaelis de Vasconcellos, Steffen; Bratschitsch, Rudolf; van der Zant, Herre S J; Castellanos-Gomez, Andres

    2014-10-01

    Tungsten diselenide (WSe2), a semiconducting transition metal dichalcogenide (TMDC), shows great potential as active material in optoelectronic devices due to its ambipolarity and direct bandgap in its single-layer form. Recently, different groups have exploited the ambipolarity of WSe2 to realize electrically tunable PN junctions, demonstrating its potential for digital electronics and solar cell applications. In this Letter, we focus on the different photocurrent generation mechanisms in a double-gated WSe2 device by measuring the photocurrent (and photovoltage) as the local gate voltages are varied independently in combination with above- and below-bandgap illumination. This enables us to distinguish between two main photocurrent generation mechanisms, the photovoltaic and photothermoelectric effect. We find that the dominant mechanism depends on the defined gate configuration. In the PN and NP configurations, photocurrent is mainly generated by the photovoltaic effect and the device displays a maximum responsivity of 0.70 mA/W at 532 nm illumination and rise and fall times close to 10 ms. Photocurrent generated by the photothermoelectric effect emerges in the PP configuration and is a factor of 2 larger than the current generated by the photovoltaic effect (in PN and NP configurations). This demonstrates that the photothermoelectric effect can play a significant role in devices based on WSe2 where a region of strong optical absorption, caused by, for example, an asymmetry in flake thickness or optical absorption of the electrodes, generates a sizable thermal gradient upon illumination.

  1. 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.

  2. 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 and…

  3. 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. PMID:19553993

  4. Impact of major volcanic eruptions on stratospheric water vapour

    NASA Astrophysics Data System (ADS)

    Löffler, M.; Brinkop, S.; Jöckel, P.

    2015-12-01

    Volcanic eruptions can have significant impact on the earth's weather and climate system. Besides the subsequent tropospheric changes also the stratosphere is 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 EMAC model, performed within the Earth System Chemistry integrated Modelling (ESCiMo) project, of which only one includes the volcanic forcing through prescribed aerosol optical properties. The results show a significant increase in stratospheric water vapour after 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 important sources for the additional water vapour in the stratosphere. Additionally, volcanic influences on the tropospheric water vapour and ENSO are evident.

  5. 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.

  6. 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...

  7. ESA DUE GlobVapour water vapor products: Validation

    SciTech Connect

    Schneider, Nadine; Schroeder, Marc; Stengel, Martin; Lindstrot, Ramus; Preusker, Rene; Collaboration: ESA DUE GlobVapour Consortium

    2013-05-10

    The main objective of the European Space Agency (ESA) Data User Element (DUE) GlobVapour project was the development of multi-annual global water vapor data sets. Since water vapour is a key climate variable it is important to have a good understanding of its behavior in the climate system. The ESA DUE GlobVapour project provides water vapor data, including error estimates, based on carefully calibrated and inter-calibrated satellite radiances in response to user requirements for long time series satellite observations. ESA DUE GlobVapour total columnar water vapor (TCWV) products derived from GOME/SCIA/GOME-2 (1996-2008) and SSM/I+MERIS (2003-2008) have been validated for the mentioned period, using satellite-based (AIRS, ATOVS) and ground-based measurements (radiosondes and microwave radiometer). The validation results are discussed in the following. The technical specifications on bias (1 kg/m{sup 2} for SSMI+MERIS and 2 kg/m{sup 2} for GOME/SCIA/GOME-2) are generally met. For more information, documents and data download follow the link: www.globvapour.info.

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

    ERIC Educational Resources Information Center

    Canpolat, Nurtac

    2006-01-01

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

  9. Varenicline Effects on Smoking, Cognition, and Psychiatric Symptoms in Schizophrenia: A Double-Blind Randomized Trial

    PubMed Central

    Si, Tian-Mei; Maayan, Lawrence; Jin, Hua; Boules, Sylvia; Sershen, Henry; Li, Chunbo; Ren, Juanjuan; Liu, Yanhong; Youseff, Mary; Lajtha, Abel; Guidotti, Alessandro; Weiser, Mark; Davis, John M.

    2016-01-01

    Schizophrenic patients have a high rate of smoking and cognitive deficits which may be related to a decreased number or responsiveness of nicotinic receptors in their brains. Varenicline is a partial nicotinic agonist which is effective as an antismoking drug in cigarette smokers, although concerns have been raised about potential psychiatric side-effects. We conducted a double-blind placebo controlled study in 87 schizophrenic smokers to evaluate the effects of varenicline (2 mg/day) on measures of smoking, cognition, psychiatric symptoms, and side-effects in schizophrenic patients who were cigarette smokers. Varenicline significantly decreased cotinine levels (P<0.001), and other objective and subjective measures of smoking (P < .01), and responses on a smoking urges scale (P = .02), more than placebo. Varenicline did not improve scores on a cognitive battery designed to test the effect of drugs on cognitive performance in schizophrenia (the MATRICS battery), either in overall MATRICS battery Composite or individual Domain scores, more than placebo. There were no significant differences between varenicline vs. placebo effects on total symptom scores on psychiatric rating scales, PANSS, SANS, or Calgary Depression scales, and there were no significant drug effects in any of these scales sub-scores when we used Benjamin-Hochberg corrected significance levels (α = .05). Varenicline patients did not show greater side-effects than placebo treated patients at any time point when controlled for baseline side-effect scores. Our study supports the use of varenicline as a safe drug for smoking reduction in schizophrenia but not as a cognitive enhancer. Trial Registration: ClinicalTrials.gov 00802919 PMID:26730716

  10. Water-lithium bromide double-effect absorption cooling analysis. Final report

    SciTech Connect

    Vliet, G.C.; Lawson, M.B.; Lithgow, R.A.

    1980-12-01

    This investigation involved the development of a numerical model for the transient simulation of the double-effect, water-lithium bromide absorption cooling machine, and the use of the model to determine the effect of the various design and input variables on the absorption unit performance. The performance parameters considered were coefficient of performance and cooling capacity. The sensitivity analysis was performed by selecting a nominal condition and determining performance sensitivity for each variable with others held constant. The variables considered in the study include source hot water, cooling water, and chilled water temperatures; source hot water, cooling water, and chilled water flow rates; solution circulation rate; heat exchanger areas; pressure drop between evaporator and absorber; solution pump characteristics; and refrigerant flow control methods. The performance sensitivity study indicated in particular that the distribution of heat exchanger area among the various (seven) heat exchange components is a very important design consideration. Moreover, it indicated that the method of flow control of the first effect refrigerant vapor through the second effect is a critical design feature when absorption units operate over a significant range of cooling capacity. The model was used to predict the performance of the Trane absorption unit with fairly good accuracy. The dynamic model should be valuable as a design tool for developing new absorption machines or modifying current machines to make them optimal based on current and future energy costs.

  11. Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect

    PubMed Central

    Silla, Josué M; Duarte, Claudimar J; Cormanich, Rodrigo A; Rittner, Roberto

    2014-01-01

    Summary The gauche effect in fluorinated alkylammonium salts is well known and attributed either to an intramolecular hydrogen bond or to an electrostatic attraction between the positively charged nitrogen and the vicinal electronegative fluorine atom. This work reports the effect of adding a fluorine atom in 2-fluoroethylamine hydrochloride on the conformational isomerism of the resulting 2,2-difluoroethylamine chloride (2). The analysis was carried out using NMR coupling constants in D2O solution, in order to mimic the equilibrium conditions in a physiological medium, in the gas phase and in implicit water through theoretical calculations. Despite the presence of σCH→σ*CF and σCH→σ*CN interactions, which usually rule the hyperconjugative gauche effect in 1,2-disubstituted ethanes, the most important forces leading to the double gauche effect (+NH3 in the gauche relationship with both fluorine atoms) in 2 are the Lewis-type ones. Particularly, electrostatic interactions are operative even in water solution, where they should be significantly attenuated, whereas hyperconjugation and hydrogen bond have secondary importance. PMID:24778743

  12. The effectiveness of a double-stem injection valve in controlling combustion in a compression-ignition engine

    NASA Technical Reports Server (NTRS)

    Spanogle, J A; Whitney, E G

    1931-01-01

    An investigation was made to determine to what extent the rates of combustion in a compression-ignition engine can be controlled by varying the rates of fuel injection. The tests showed that the double-stem valve operated satisfactorily under all normal injection conditions; the rate of injection has a definite effect on the rate of combustion; the engine performance with the double-stem valve was inferior to that obtained with a single-stem valve; and the control of injection rates permitted by an injection valve of two stages of discharge is not sufficient to effect the desired rates of combustion.

  13. An evaluation of materials and methods for vapour measurement of the isotopic composition of pore water in deep, unsaturated zones.

    PubMed

    Pratt, Dyan L; Lu, Mengna; Lee Barbour, S; Jim Hendry, M

    2016-01-01

    The development of in situ vapour sampling methods to measure δ(2)H and δ(18)O in pore water of deep, unsaturated soil profiles, including mine tailings and waste rock, is required to improve our ability to track water migration through these deposits. To develop appropriate field sampling methods, a laboratory study was first undertaken to evaluate potential materials and sampling methods to collect and analyse vapour samples from unsaturated mine waste. Field methods were developed based on these findings and tested at two mine sites using either on-site analyses with a portable isotope laser spectrometer or sample collection and storage prior to laboratory analyses. The field sites included a series of deep (>50 m) multiport profiles within a coal waste rock dump and open wells installed in a sand tailings dyke at an oil sands mine. Laboratory results show that memory effects in sample bags and tubing require 3-5 pore volumes of vapour flushing prior to sample collection and sample storage times are limited to 24 h. Field sampling highlighted a number of challenges including the need to correct for sample humidity and in situ temperature. Best results were obtained when a portable laser spectrometer was used to measure vapour samples in situ. PMID:27002493

  14. Evaluating the vapour shift concept in agriculture: some aspects

    NASA Astrophysics Data System (ADS)

    Schmidt, S.; Metselaar, K.; van Dam, J. C.; Klik, A.

    2009-04-01

    Human population growth leads to an increasing pressure on freshwater resources. By 2050 Falkenmark et al. (2004) estimate a global water deficit for crop production of 5800 km3.y-1. This has important consequences for management of fresh water resources at different scales, and new strategies at different scales are required. One of the strategies suggested is that of managing crops in such a way that the use of rainfall and irrigation is shifted as much as possible from evaporation towards transpiration, a so-called vapour shift. The suggested savings are in the order of 330 km3.y-1, and are based on estimates of the magnitude of three processes: Reducing early season evaporation; increasing canopy cover; and increasing yield levels. The vapour shift concept was evaluated empirically, and in a simulation study. The empirical evaluation using results for wheat, maize, millet, cotton, and barley suggests the estimate of potential savings is 37% lower than the estimate by Falkenmark et al. (2004). The uncertainty is large and due to the limited number of experiments in which a separation of evapotranspiration in evaporation and transpiration has been made over the entire growing season. This suggests that theoretical support for the vapour shift concept should become more important. In the simulation approach two management options, mulching and planting density, are evaluated for a site in India for an irrigated wheat crop using a simulation approach for water limited crop yield. Given the simulation model used, and the management options investigated, the assumption implicit in the vapour shift concept - decreasing evaporation with increasing yield level - does not hold in irrigated areas, or in areas in which water is the most limiting factor. This suggests that vapour shift will be largest in those areas where nutrients and pests- and diseases are still limiting or reducing crop yields, and measures are taken to reduce those limitations.

  15. Molecular dynamics studies of aqueous silica nanoparticle dispersions: salt effects on the double layer formation.

    PubMed

    de Lara, Lucas S; Rigo, Vagner A; Michelon, Mateus F; Metin, Cigdem O; Nguyen, Quoc P; Miranda, Caetano R

    2015-08-19

    The ion distribution around hydroxylated silica nanoparticles (NP-H) dispersed in brine was investigated by fully atomistic molecular dynamics. The NP-H dispersions in aqueous electrolyte media are simulated in solutions of varying salinity (NaCl, CaCl2, and MgCl2), salt concentration (0.06  ×  10(-3) to 3.00  ×  10(-3) mole fraction [Formula: see text]), and temperature (300 and 350 K) at 1 atm. The NP-H models reproduce the observed experimental concentration of silanol and geminal surface sites, which are responsible for local charge variations on the nanoparticles' surface. Interestingly, under certain salt concentration conditions, the formation of an electrical double layer (DL) around the overall neutral NP-H occurs. The resulting DLs are attenuated with increasing temperature for all evaluated salts. With increasing salt concentration, a sign inversion of the effective charge at the first ion layer is observed, which modifies the electrostatic environment around the nanoparticle. The minimum salt concentration that leads to a DL formation at 300 K is 1.05  ×  10(-3), 0.37  ×  10(-3), and 0.06  ×  10(-3) χs for NaCl, CaCl2, and MgCl2, respectively. The width of the DL decreases sequentially in ionic strength from NaCl to CaCl2 to MgCl2, which is similar to that found for highly charged surfaces. These results are in line with our previous experimental data for negative charged NP-H. All together, these observations suggest an interplay mechanism between the formation and narrowing of electric double layers on the stability of NP dispersions in both neutral and negatively charged NP-H.

  16. Molecular dynamics studies of aqueous silica nanoparticle dispersions: salt effects on the double layer formation

    NASA Astrophysics Data System (ADS)

    de Lara, Lucas S.; Rigo, Vagner A.; Michelon, Mateus F.; Metin, Cigdem O.; Nguyen, Quoc P.; Miranda, Caetano R.

    2015-08-01

    The ion distribution around hydroxylated silica nanoparticles (NP-H) dispersed in brine was investigated by fully atomistic molecular dynamics. The NP-H dispersions in aqueous electrolyte media are simulated in solutions of varying salinity (NaCl, CaCl2, and MgCl2), salt concentration (0.06  ×  10-3 to 3.00  ×  10-3 mole fraction {χ\\text{s}} ), and temperature (300 and 350 K) at 1 atm. The NP-H models reproduce the observed experimental concentration of silanol and geminal surface sites, which are responsible for local charge variations on the nanoparticles’ surface. Interestingly, under certain salt concentration conditions, the formation of an electrical double layer (DL) around the overall neutral NP-H occurs. The resulting DLs are attenuated with increasing temperature for all evaluated salts. With increasing salt concentration, a sign inversion of the effective charge at the first ion layer is observed, which modifies the electrostatic environment around the nanoparticle. The minimum salt concentration that leads to a DL formation at 300 K is 1.05  ×  10-3, 0.37  ×  10-3, and 0.06  ×  10-3 {χ\\text{s}} for NaCl, CaCl2, and MgCl2, respectively. The width of the DL decreases sequentially in ionic strength from NaCl to CaCl2 to MgCl2, which is similar to that found for highly charged surfaces. These results are in line with our previous experimental data for negative charged NP-H. All together, these observations suggest an interplay mechanism between the formation and narrowing of electric double layers on the stability of NP dispersions in both neutral and negatively charged NP-H.

  17. Experimental determination and theoretical framework of kinetic fractionation at the water vapour - ice interface at low temperature.

    NASA Astrophysics Data System (ADS)

    Casado, M.; Prie, F.

    2015-12-01

    Isotopic fraction of water enables climate reconstruction from ice cores. The use of different heavy isotopes of water such as H218O, H217O or HDO gives information about local temperature but also temperature and humidity of water vapour sources. Quantification of these parameters relies on the good knowledge of equilibrium and kinetic isotopic fractionation at each step of the water cycle. The strongest limitation when interpreting water isotopes in remote Antarctic ice cores is the formulation of the isotopic fractionation at solid condensation (vapour to ice). This classical formulation also implies a good knowledge of coefficients for equilibrium fractionation and water vapour diffusion in air as well as supersaturation in clouds. The uncertainties lying on these different parameters make the formulation of isotopic fractionation at solid condensation only empirical. Here, we make use (1) of recent development in the measurements of water isotopes in the water vapour through infra-red spectroscopy and (2) of the possibility to measure accurately 17O-excess of water to test the classical formulation and parameterization of isotopic fractionation at solid condensation. A first experiment involving very strong supersaturation evidences a strong kinetic effect on 17O-excess on solid condensation, similar to d-excess. It also shows the limits of the classical formulation of water isotopic fractionation during solid condensation estimation at very low temperature. A second experiment performed in a cloud chamber in controlled conditions uses CRDS instruments to depict the spatial variability of water vapour isotopic composition due to diffusion (kinetic effect) during solid condensation. These experiments are in agreement with a new theoretical model that we present for the competition between diffusions of different isotopes. This preliminary study opens new perspectives to revisit the classical formulation of water isotopic fractionation during solid condensation

  18. IS THE BLAZHKO EFFECT THE BEATING OF A NEAR-RESONANT DOUBLE-MODE PULSATION?

    SciTech Connect

    Bryant, Paul H.

    2015-03-20

    In this paper it is shown that the Blazhko effect may result from a near-resonant type of multi-mode pulsation, where two (or sometimes more) periodic oscillations with slightly different frequencies gradually slip in phase, producing a beat frequency type of modulation. Typically one of these oscillations is strongly non-sinusoidal. Two oscillations are sufficient for the standard Blazhko effect; additional oscillations are needed to explain multi-frequency modulation. Previous work on this hypothesis by Arthur N. Cox and others is extended in this paper by developing a simple (non-hydrocode) model that can accurately reproduce several important features found in Kepler data for RR Lyr, including the pulsation waveform; the upper and lower Blazhko envelope functions; and the motion, disappearance, and reappearance of the bump feature. The non-sinusoidal oscillation is probably generated by the fundamental mode and the other oscillations are probably generated by nonradial modes. This model provides an explanation for the strong asymmetry observed in the side peak spectra of most RR Lyrae stars. The motion and disappearance of the bump feature are shown to be illusions, just artifacts of combining the oscillations. V445 Lyr is presented as an example with dual modulation. The mysterious double-maxima waveform observed for this star is explained, providing additional strong evidence that this beating-modes hypothesis is correct. Problems with other recent explanations of the Blazhko effect are discussed in some detail.

  19. 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

  20. Ionic Asymmetry and Solvent Excluded Volume Effects on Spherical Electric Double Layers: A Density Functional Approach

    SciTech Connect

    Medasani, Bharat; Ovanesyan, Zaven; Thomas, Dennis G.; Sushko, Maria L.; Marucho, Marcelo

    2014-05-29

    In this article we present a classical density functional theory for electrical double layers of spherical macroions that extends the capabilities of conventional approaches by accounting for electrostatic ion correlations, size asymmetry and excluded volume effects. The approach is based on a recent approximation introduced by Hansen-Goos and Roth for the hard sphere excess free energy of inhomogeneous fluids (J. Chem. Phys. 124, 154506). It accounts for the proper and efficient description of the effects of ionic asymmetry and solvent excluded volume, especially at high ion concentrations and size asymmetry ratios including those observed in experimental studies. Additionally, we utilize a leading functional Taylor expansion approximation of the ion density profiles. In addition, we use the Mean Spherical Approximation for multi-component charged hard sphere fluids to account for the electrostatic ion correlation effects. These approximations are implemented in our theoretical formulation into a suitable decomposition of the excess free energy which plays a key role in capturing the complex interplay between charge correlations and excluded volume effects. We perform Monte Carlo simulations in various scenarios to validate the proposed approach, obtaining a good compromise between accuracy and computational cost. We use the proposed computational approach to study the effects of ion size, ion size asymmetry and solvent excluded volume on the ion profiles, integrated charge, mean electrostatic potential, and ionic coordination number around spherical macroions in various electrolyte mixtures. Our results show that both solvent hard sphere diameter and density play a dominant role in the distribution of ions around spherical macroions, mainly for experimental water molarity and size values where the counterion distribution is characterized by a tight binding to the macroion, similar to that predicted by the Stern model.

  1. Ionic asymmetry and solvent excluded volume effects on spherical electric double layers: A density functional approach

    NASA Astrophysics Data System (ADS)

    Medasani, Bharat; Ovanesyan, Zaven; Thomas, Dennis G.; Sushko, Maria L.; Marucho, Marcelo

    2014-05-01

    In this article, we present a classical density functional theory for electrical double layers of spherical macroions that extends the capabilities of conventional approaches by accounting for electrostatic ion correlations, size asymmetry, and excluded volume effects. The approach is based on a recent approximation introduced by Hansen-Goos and Roth for the hard sphere excess free energy of inhomogeneous fluids [J. Chem. Phys. 124, 154506 (2006); Hansen-Goos and Roth, J. Phys.: Condens. Matter 18, 8413 (2006)]. It accounts for the proper and efficient description of the effects of ionic asymmetry and solvent excluded volume, especially at high ion concentrations and size asymmetry ratios including those observed in experimental studies. Additionally, we utilize a leading functional Taylor expansion approximation of the ion density profiles. In addition, we use the mean spherical approximation for multi-component charged hard sphere fluids to account for the electrostatic ion correlation effects. These approximations are implemented in our theoretical formulation into a suitable decomposition of the excess free energy which plays a key role in capturing the complex interplay between charge correlations and excluded volume effects. We perform Monte Carlo simulations in various scenarios to validate the proposed approach, obtaining a good compromise between accuracy and computational cost. We use the proposed computational approach to study the effects of ion size, ion size asymmetry, and solvent excluded volume on the ion profiles, integrated charge, mean electrostatic potential, and ionic coordination number around spherical macroions in various electrolyte mixtures. Our results show that both solvent hard sphere diameter and density play a dominant role in the distribution of ions around spherical macroions, mainly for experimental water molarity and size values where the counterion distribution is characterized by a tight binding to the macroion, similar to that

  2. Ionic asymmetry and solvent excluded volume effects on spherical electric double layers: a density functional approach.

    PubMed

    Medasani, Bharat; Ovanesyan, Zaven; Thomas, Dennis G; Sushko, Maria L; Marucho, Marcelo

    2014-05-28

    In this article, we present a classical density functional theory for electrical double layers of spherical macroions that extends the capabilities of conventional approaches by accounting for electrostatic ion correlations, size asymmetry, and excluded volume effects. The approach is based on a recent approximation introduced by Hansen-Goos and Roth for the hard sphere excess free energy of inhomogeneous fluids [J. Chem. Phys. 124, 154506 (2006); Hansen-Goos and Roth, J. Phys.: Condens. Matter 18, 8413 (2006)]. It accounts for the proper and efficient description of the effects of ionic asymmetry and solvent excluded volume, especially at high ion concentrations and size asymmetry ratios including those observed in experimental studies. Additionally, we utilize a leading functional Taylor expansion approximation of the ion density profiles. In addition, we use the mean spherical approximation for multi-component charged hard sphere fluids to account for the electrostatic ion correlation effects. These approximations are implemented in our theoretical formulation into a suitable decomposition of the excess free energy which plays a key role in capturing the complex interplay between charge correlations and excluded volume effects. We perform Monte Carlo simulations in various scenarios to validate the proposed approach, obtaining a good compromise between accuracy and computational cost. We use the proposed computational approach to study the effects of ion size, ion size asymmetry, and solvent excluded volume on the ion profiles, integrated charge, mean electrostatic potential, and ionic coordination number around spherical macroions in various electrolyte mixtures. Our results show that both solvent hard sphere diameter and density play a dominant role in the distribution of ions around spherical macroions, mainly for experimental water molarity and size values where the counterion distribution is characterized by a tight binding to the macroion, similar to that

  3. The Effect of Nefopam on Postoperative Fentanyl Consumption: A Randomized, Double-blind Study

    PubMed Central

    Moon, Jee Youn; Lee, Shin Young; Lee, Mi Kyung; Kim, Jung Eun; Lee, Ji Eun; Lee, So Hyun

    2016-01-01

    Background Nefopam is a non-opioid, non-steroidal, centrally acting analgesic drug. The concomitant use of opioids and nefopam is believed to have many advantages over the administration of opioids alone for postoperative pain management. We conducted a randomized, double-blind study to determine the fentanyl-sparing effect of co-administration of nefopam with fentanyl for postoperative pain management via patient controlled analgesia (PCA). Methods Ninety female patients who underwent laparoscopic total hysterectomy under general anesthesia were randomized into 3 groups, Group A, fentanyl 1,000 µg; Group B, fentanyl 500 µg + nefopam 200 mg; and Group C, fentanyl 500 µg + nefopam 400 mg, in a total volume of 100 ml PCA to be administered over the first 48 h postoperatively without basal infusion. The primary outcome was total fentanyl consumption during 48 h; secondary outcomes included pain scores and incidence of side effects. Results Eighty-one patients were included in the analysis. The overall fentanyl-sparing effects of PCA with concomitant administration of nefopam during the first 48 h postoperatively were 54.5% in Group B and 48.9% group C. Fentanyl use was not significantly different between Groups B and C despite the difference in the nefopam dose. There were no differences among the three groups in terms of PCA-related side effects, although the overall sedation score of Group B was significantly lower than that of Group A. Conclusions The concomitant administration of nefopam with fentanyl for postoperative pain management may allow reduction of fentanyl dose, thereby reducing the risk of opioid-related adverse effects. PMID:27103966

  4. Ionic asymmetry and solvent excluded volume effects on spherical electric double layers: a density functional approach.

    PubMed

    Medasani, Bharat; Ovanesyan, Zaven; Thomas, Dennis G; Sushko, Maria L; Marucho, Marcelo

    2014-05-28

    In this article, we present a classical density functional theory for electrical double layers of spherical macroions that extends the capabilities of conventional approaches by accounting for electrostatic ion correlations, size asymmetry, and excluded volume effects. The approach is based on a recent approximation introduced by Hansen-Goos and Roth for the hard sphere excess free energy of inhomogeneous fluids [J. Chem. Phys. 124, 154506 (2006); Hansen-Goos and Roth, J. Phys.: Condens. Matter 18, 8413 (2006)]. It accounts for the proper and efficient description of the effects of ionic asymmetry and solvent excluded volume, especially at high ion concentrations and size asymmetry ratios including those observed in experimental studies. Additionally, we utilize a leading functional Taylor expansion approximation of the ion density profiles. In addition, we use the mean spherical approximation for multi-component charged hard sphere fluids to account for the electrostatic ion correlation effects. These approximations are implemented in our theoretical formulation into a suitable decomposition of the excess free energy which plays a key role in capturing the complex interplay between charge correlations and excluded volume effects. We perform Monte Carlo simulations in various scenarios to validate the proposed approach, obtaining a good compromise between accuracy and computational cost. We use the proposed computational approach to study the effects of ion size, ion size asymmetry, and solvent excluded volume on the ion profiles, integrated charge, mean electrostatic potential, and ionic coordination number around spherical macroions in various electrolyte mixtures. Our results show that both solvent hard sphere diameter and density play a dominant role in the distribution of ions around spherical macroions, mainly for experimental water molarity and size values where the counterion distribution is characterized by a tight binding to the macroion, similar to that

  5. 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.

  6. 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

  7. Oxygen-organophosphate linkage in hemoglobin A. The double hump effect.

    PubMed Central

    Kister, J; Poyart, C; Edelstein, S J

    1987-01-01

    At low concentrations of chloride ions, and in the presence of nonsaturating concentrations of organophosphates, the oxygen equilibrium curves (OEC) for solutions of human adult hemoglobin exhibit a biphasic shape conveniently revealed by graphical analysis of the first derivative of the Hill equation with a characteristic form that we call "the double hump effect." This shape, observed for sub-saturating concentrations of organophosphates, stands in marked contrast to the simple lateral shifts of the OEC represented largely by scaling factors when pH or chloride are varied. In the case of protons or chloride, there is a self-buffering effect due to the presence of a large reservoir of proton or chloride binding sites not necessarily linked to oxygen, whereas such sites do not exist in the case of organophosphates. In addition, in the former case, we are dealing with curves measured at constant activity of the effector, while in the latter, at constant concentration. In the presence of saturating concentrations of inositol hexaphosphate (IHP), at low chloride concentration, the entire OEC is shifted to the right, including both its upper and lower asymptotes, indicating a decrease in the intrinsic oxygen affinities of both the T and R states. Theoretical considerations leading to a successful modeling of OEC obtained under nonsaturating and saturating concentrations of IHP required an expanded two-state allosteric model in which IHP-dependent variations in oxygen association constants for both the T and R conformations are taken into account. PMID:3676434

  8. Improved double-gate armchair silicene nanoribbon field-effect-transistor at large transport bandgap

    NASA Astrophysics Data System (ADS)

    Mohsen, Mahmoudi; Zahra, Ahangari; Morteza, Fathipour

    2016-01-01

    The electrical characteristics of a double-gate armchair silicene nanoribbon field-effect-transistor (DG ASiNR FET) are thoroughly investigated by using a ballistic quantum transport model based on non-equilibrium Green’s function (NEGF) approach self-consistently coupled with a three-dimensional (3D) Poisson equation. We evaluate the influence of variation in uniaxial tensile strain, ribbon temperature and oxide thickness on the on-off current ratio, subthreshold swing, transconductance and the delay time of a 12-nm-length ultranarrow ASiNR FET. A novel two-parameter strain magnitude and temperature-dependent model is presented for designing an optimized device possessing balanced amelioration of all the electrical parameters. We demonstrate that employing HfO2 as the gate insulator can be a favorable choice and simultaneous use of it with proper combination of temperature and strain magnitude can achieve better device performance. Furthermore, a general model power (GMP) is derived which explicitly provides the electron effective mass as a function of the bandgap of a hydrogen passivated ASiNR under strain.

  9. Alignment effects in two-photon double ionization of H2 in femtosecond xuv laser pulses

    NASA Astrophysics Data System (ADS)

    Guan, Xiaoxu; Bartschat, Klaus; Schneider, Barry I.

    2011-09-01

    Triple-differential cross sections for two-photon double ionization of the aligned hydrogen molecule at the equilibrium distance are presented for a central photon energy of 30 eV. The temporal response of the laser-driven molecule is investigated by solving the time-dependent Schrödinger equation in full dimensionality using two-center elliptical coordinates and a finite-element discrete-variable-representation approach. The molecular orientation is found to have a strong effect on the emission modes of the two correlated photoelectrons. This molecular effect is most noticeable when the molecular axis and the laser polarization vector are oriented parallel to each other. For intermediate cases between the parallel and perpendicular geometries, the dominant emission modes for two-electron ejection oscillate between those for the two extreme cases. The contributions from different ionization channels are also analyzed in detail. Depending on the emission direction of the reference electron, the interference contributions from the various channels can be constructive or destructive at small alignment angles, while they always contribute constructively to the triple-differential cross sections near the perpendicular geometry.

  10. Electrical and Optical Gain Lever Effects in InGaAs Double Quantum Well Diode Lasers

    SciTech Connect

    Pocha, M D; Goddard, L L; Bond, T C; Nikolic, R J; Vernon, S P; Kallman, J S; Behymer, E M

    2007-01-03

    In multisection laser diodes, the amplitude or frequency modulation (AM or FM) efficiency can be improved using the gain lever effect. To study gain lever, InGaAs double quantum well (DQW) edge emitting lasers have been fabricated with integrated passive waveguides and dual sections providing a range of split ratios from 1:1 to 9:1. Both the electrical and the optical gain lever have been examined. An electrical gain lever with greater than 7 dB enhancement of AM efficiency was achieved within the range of appropriate DC biasing currents, but this gain dropped rapidly outside this range. We observed a 4 dB gain in the optical AM efficiency under non-ideal biasing conditions. This value agreed with the measured gain for the electrical AM efficiency under similar conditions. We also examined the gain lever effect under large signal modulation for digital logic switching applications. To get a useful gain lever for optical gain quenched logic, a long control section is needed to preserve the gain lever strength and a long interaction length between the input optical signal and the lasing field of the diode must be provided. The gain lever parameter space has been fully characterized and validated against numerical simulations of a semi-3D hybrid beam propagation method (BPM) model for the coupled electron-photon rate equation. We find that the optical gain lever can be treated using the electrical injection model, once the absorption in the sample is known.

  11. ANTIPLAQUE AND ANTIGINGIVITIS EFFECT OF LIPPIA SIDOIDES. A DOUBLE-BLIND CLINICAL STUDY IN HUMANS

    PubMed Central

    Rodrigues, Ítalo Sarto Carvalho; Tavares, Vinícius Nascimento; Pereira, Sérgio Luís da Silva; da Costa, Flávio Nogueira

    2009-01-01

    Objectives: The antiplaque and antigingivitis effect of Lippia Sidoides (LS) was evaluated in this in vivo investigation. Material and Methods: Twenty-three subjects participated in a cross-over, double-blind clinical study, using 21-day partial-mouth experimental model of gingivitis. A toothshield was constructed for each volunteer, avoiding the brushing of the 4 experimental posterior teeth in the lower left quadrant. The subjects were randomly assigned initially to use either the placebo gel (control group) or the test gel, containing 10% LS (test group). Results: The clinical results showed statistically significant differences for plaque index (PLI) (p<0.01) between days 0 and 21 in both groups, however only the control group showed statistically significant difference (p<0.01) for the bleeding (IB) and gingival (GI) index within the experimental period of 21 days. On day 21, the test group presented significantly better results than the control group with regard to the GI (p<0.05). Conclusions: The test gel containing 10% LS was effective in the control of gingivitis. PMID:19936516

  12. Effects of double-strand break repair proteins on vertebrate telomere structure

    PubMed Central

    Wei, Chao; Skopp, Rose; Takata, Minoru; Takeda, Shunichi; Price, Carolyn M.

    2002-01-01

    Although telomeres are not recognized as double-strand breaks (DSBs), some DSB repair proteins are present at telomeres and are required for telomere maintenance. To learn more about the telomeric function of proteins from the homologous recombination (HR) and non-homologous end joining pathways (NHEJ), we have screened a panel of chicken DT40 knockout cell lines for changes in telomere structure. In contrast to what has been observed in Ku-deficient mice, we found that Ku70 disruption did not result in telomere–telomere fusions and had no effect on telomere length or the structure of the telomeric G-strand overhang. G-overhang length was increased by Rad51 disruption but unchanged by disruption of DNA-PKcs, Mre11, Rad52, Rad54, XRCC2 or XRCC3. The effect of Rad51 depletion was unexpected because gross alterations in telomere structure have not been detected in yeast HR mutants. Thus, our results indicate that Rad51 has a previously undiscovered function at vertebrate telomeres. They also indicate that Mre11 is not required to generate G-overhangs. Although Mre11 has been implicated in overhang generation, overhang structure had not previously been examined in Mre11-deficient cells. Overall our findings indicate that there are significant species-specific differences in the telomeric function of DSB repair proteins. PMID:12087170

  13. Modified Bell-Plesset effect with compressibility: Application to double-shell ignition target designs

    NASA Astrophysics Data System (ADS)

    Amendt, Peter; Colvin, J. D.; Ramshaw, J. D.; Robey, H. F.; Landen, O. L.

    2003-03-01

    The effect of spherical convergence on the fluid stability of collapsing and expanding bubbles was originally treated by Bell [Los Alamos Scientific Laboratory Report No. LA-1321 (1951)] and Plesset [J. Appl. Phys. 25, 96 (1954)]. The additional effect of fluid compressibility was also considered by Bell but was limited to the case of nonzero density on only one side of a fluid interface. A more general extension is developed which considers distinct time-dependent uniform densities on both sides of an interface in a spherically converging geometry. A modified form of the velocity potential is used that avoids an unphysical divergence at the origin [Goncharov et al., Phys. Plasmas 7, 5118 (2000); Lin et al., Phys. Fluids 14, 2925 (2002)]. Two consequences of this approach are that an instability proposed by Plesset for an expanding bubble in the limit of large interior density is now absent and application to inertial confinement fusion studies of stability becomes feasible. The model is applied to a proposed ignition double-shell target design [Amendt et al., Phys. Plasmas 9, 2221 (2002)] for the National Ignition Facility [Paisner et al., Laser Focus World 30, 75 (1994)] for studying the stability of the inner surface of an imploding high-Z inner shell. Application of the Haan [Phys. Rev. A 39, 5812 (1989)] saturation criterion suggests that ignition is possible.

  14. Quantum Hall effect in an InAs /AlSb double quantum well

    NASA Astrophysics Data System (ADS)

    Yakunin, M. V.; Podgornykh, S. M.; Sadofyev, Yu. G.

    2009-01-01

    Double quantum wells (DQWs) were first implemented in the InAs /AlSb heterosystem, which is characterized by a large Landé g factor ∣g∣=15 of the InAs layers forming the well, much larger than the bulk g factor ∣g∣=0.4 of the GaAs in conventional GaAs /AlGaAs DQWs. The quality of the samples is good enough to permit observation of a clear picture of the quantum Hall effect (QHE). Despite the small tunneling gap, which is due to the large barrier height (1.4eV), features with odd filling factors ν =3,5,7,… are present in the QHE, due to collectivized interlayer states of the DQW. When the field is rotated relative to the normal to the layers, the ν =3 state is suppressed, confirming the collectivized nature of that state and denying that it could owe its existence to a strong asymmetry of the DQW. Previously the destruction of the collectivized QHE states by a parallel field had been observed only for the ν =1 state. The observation of a similar effect for ν =3 in an InAs /AlSb DQW may be due to the large bulk g factor of InAs.

  15. Effect of fatigue on double pole kinematics in sprint cross-country skiing.

    PubMed

    Zory, Raphael; Vuillerme, Nicolas; Pellegrini, Barbara; Schena, Federico; Rouard, Annie

    2009-02-01

    The aim of the present study was to examine the effect of fatigue (physiological, mechanical, and muscular parameters) induced by a sprint simulation on kinematic parameters (cycle, phases, and joints angles) of the double pole technique. Eight elite skiers were tested for knee extensor strength and upper body power both before and after a three-bout simulation of sprint racing. They were video analyzed during the final part of the test track of bouts 1 and 3 using a digital camera. Results showed that skiers were in a fatigue state (decrease of the knee extensors voluntary force (-10.4+/-10.4%) and upper body power output (-11.1+/-8.7%) at the end of the sprint. During bout 3, the final spurt and cycle velocities decreased significantly (-7.5+/-12.3%; -13.2+/-9.5%; both p<.05). Angular patterns were only slightly modified between bouts 1 and 3 with trunk, hip, and pole angles being significantly greater for the third bout. The decrease of hip and trunk flexion and the lower inclination of the pole during the poling phase suggested a reduced effectiveness of the force application which could lead to a decrease in the cycle velocity.

  16. Venus Water Vapour Profiles Obtained by SOIR/VEx

    NASA Astrophysics Data System (ADS)

    Chamberlain, Sarah; Wilquet, Valerie; Mahieux, Arnaud; Robert, Severine; Thomas, Ian; Carine Vandaele, Ann; Bertaux, Jean-Loup

    2015-04-01

    We present up-to-date observations of the water vapour profile at the Venus terminator, between altitudes of 70 - 110km. The data were obtained by the Solar Occultation in the InfraRed (SOIR) instrument on board Venus Express (VEx). The SOIR instrument allows observations of trace gas profiles at altitudes within the Venus lower thermosphere and mesosphere. Due to the observational technique, all observations are taken at the Venus terminator, on either or both of the evening and morning side of the planet and covering almost all latitudes. These are key locations for study as the mesosphere/thermosphere altitudes correspond to the transition in dynamical regime from a retrograde zonal flow to sub-solar to antisolar flow (approximately 90 km) and at these altitudes we expect a steeper than normal temperature gradient across the terminator which would drive chemical reactions and dynamical flows. Water vapour in the mesosphere is involved in the cloud formation process and contributes to several chemical cycles. Isotopologue ratio studies also contribute towards understanding the evolution of the Venus climate and atmosphere. Determining the abundance, distribution and variability of water vapour is therefore a key element to understanding the development, maintenance and links between dynamical features, important chemical cycles and the evolution of the Venus atmosphere. Both water vapour isotopologues are targeted simultaneously in the majority of dedicated SOIR water vapour observations. H2O is detected between 70 - 110km and HDO is detected between 70 - 95km altitude. Early SOIR water vapour observations were published in 2007 and 2008. Previous results show a depletion in the volume mixing ratio (VMR) at 85km in both HDO and H2O and an increase in HDO/H2O ratio above the clouds. No noticeable temporal variability was detected. Numerous subsequent H2O and HDO SOIR observations have been obtained between 2007 - 2014 and with recent improvements in instrument

  17. The effect of the laser wavelength on collinear double pulse laser induced breakdown spectroscopy (DP-LIBS)

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Lin, Yanqing; Liu, Jing; Fan, Shuang; Xu, Zhuopin; Huang, Qing; Wu, Yuejin

    2016-05-01

    The pulsed lasers at wavelengths of 532 nm and 1064 nm were used as two beams of light for collinear double pulse laser induced breakdown spectroscopy (DP-LIBS). By changing the time sequence of two beams of different lasers, we studied the effect of the interval of two pulses of DP-LIBS on spectral signals compared with single pulsed (SP) LIBS.

  18. Model simulation for periodic double-peaked outbursts in blazar OJ 287: binary black hole plus lighthouse effect

    NASA Astrophysics Data System (ADS)

    Qian, Shan-Jie

    2015-05-01

    The mechanism of formation for double-peaked optical outbursts observed in blazar OJ 287 is studied. It is shown that they could be explained in terms of a lighthouse effect for superluminal optical knots ejected from the center of the galaxy that move along helical magnetic fields. It is assumed that the orbital motion of the secondary black hole in the supermassive binary black hole system induces the 12-year quasi-periodicity in major optical outbursts by the interaction with the disk around the primary black hole. This interaction between the secondary black hole and the disk of the primary black hole (e.g. tidal effects or magnetic coupling) excites or injects plasmons (or relativistic plasmas plus magnetic field) into the jet which form superluminal knots. These knots are assumed to move along helical magnetic field lines to produce the optical double-peaked outbursts by the lighthouse effect. The four double-peaked outbursts observed in 1972, 1983, 1995 and 2005 are simulated using this model. It is shown that such lighthouse models are quite plausible and feasible for fitting the double-flaring behavior of the outbursts. The main requirement may be that in OJ 287 there exists a rather long (~40-60 pc) highly collimated zone, where the lighthouse effect occurs.

  19. Effects of Naloxone and Naltrexone on Self-Injury: A Double-Blind, Placebo-Controlled Analysis.

    ERIC Educational Resources Information Center

    Barrett, Rowland P.; And Others

    1989-01-01

    Double blind study compared effects of two drug treatments, naloxone hydrochloride and naltrexone hydrochloride, on self-injurious behavior of a 12-year-old mentally retarded and autistic girl. Self-injury increased with naloxone treatment but decreased to near zero with naltrexone, a change which persisted at follow-up 22 months after treatment.…

  20. Radiative decays of double heavy baryons in a relativistic constituent three-quark model including hyperfine mixing effects

    SciTech Connect

    Branz, Tanja; Faessler, Amand; Gutsche, Thomas; Lyubovitskij, Valery E.; Oexl, Bettina; Ivanov, Mikhail A.; Koerner, Juergen G.

    2010-06-01

    We study flavor-conserving radiative decays of double-heavy baryons using a manifestly Lorentz covariant constituent three-quark model. Decay rates are calculated and compared to each other in the full theory, keeping masses finite, and also in the heavy quark limit. We discuss in some detail hyperfine mixing effects.

  1. Determination of effective mechanical properties of a double-layer beam by means of a nano-electromechanical transducer

    SciTech Connect

    Hocke, Fredrik; Pernpeintner, Matthias; Gross, Rudolf; Zhou, Xiaoqing; Kippenberg, Tobias J.; Schliesser, Albert; Huebl, Hans

    2014-09-29

    We investigate the mechanical properties of a doubly clamped, double-layer nanobeam embedded into an electromechanical system. The nanobeam consists of a highly pre-stressed silicon nitride and a superconducting niobium layer. By measuring the mechanical displacement spectral density both in the linear and the nonlinear Duffing regime, we determine the pre-stress and the effective Young's modulus of the nanobeam. An analytical double-layer model quantitatively corroborates the measured values. This suggests that this model can be used to design mechanical multilayer systems for electro- and optomechanical devices, including materials controllable by external parameters such as piezoelectric, magnetostrictive, or in more general multiferroic materials.

  2. Height-tapered double cantilever beam specimen for study of rate effects on fracture toughness of composites

    NASA Technical Reports Server (NTRS)

    Yaniv, Gershon; Daniel, Isaac M.

    1988-01-01

    Loading rate effects on the mode I delamination fracture toughness of AS4/3501-6 graphite/epoxy are presently studied by means of a height-tapered double-cantilever beam specimen whose height contour is designed to furnish a slightly decreasing compliance with increasing crack length, in order to yield a stable and smooth crack propagation at high loading rates. This specimen geometry also allows much higher crack propagation velocities to be obtained with either uniform or width-tapered double cantilever beam specimens.

  3. Determination of effective mechanical properties of a double-layer beam by means of a nano-electromechanical transducer

    NASA Astrophysics Data System (ADS)

    Hocke, Fredrik; Pernpeintner, Matthias; Zhou, Xiaoqing; Schliesser, Albert; Kippenberg, Tobias J.; Huebl, Hans; Gross, Rudolf

    2014-09-01

    We investigate the mechanical properties of a doubly clamped, double-layer nanobeam embedded into an electromechanical system. The nanobeam consists of a highly pre-stressed silicon nitride and a superconducting niobium layer. By measuring the mechanical displacement spectral density both in the linear and the nonlinear Duffing regime, we determine the pre-stress and the effective Young's modulus of the nanobeam. An analytical double-layer model quantitatively corroborates the measured values. This suggests that this model can be used to design mechanical multilayer systems for electro- and optomechanical devices, including materials controllable by external parameters such as piezoelectric, magnetostrictive, or in more general multiferroic materials.

  4. Theoretical Analysis of the Effect of C═C Double Bonds on the Low-Temperature Reactivity of Alkenylperoxy Radicals.

    PubMed

    You, Xiaoqing; Chi, Yawei; He, Tanjin

    2016-08-01

    Biodiesel contains a large proportion of unsaturated fatty acid methyl esters. Its combustion characteristics, especially its ignition behavior at low temperatures, have been greatly affected by these C═C double bonds. In this work, we performed a theoretical analysis of the effect of C═C double bonds on the low-temperature reactivity of alkenylperoxy radicals, the key intermediates from the low-temperature combustion of biodiesel. To understand how double bonds affect the fate of peroxy radicals, we selected three representative peroxy radicals from heptane, heptene, and heptadiene having zero, one, and two double C═C bonds, respectively, for study. The potential energy surfaces were explored at the CBS-QB3 level, and the reaction rate constants were computed using canonical/variational transition state theories. We have found that the double bond is responsible for the very different bond dissociation energies of the various types of C-H bonds, which in turn affect significantly the reaction kinetics of alkenylperoxy radicals.

  5. Theoretical Analysis of the Effect of C═C Double Bonds on the Low-Temperature Reactivity of Alkenylperoxy Radicals.

    PubMed

    You, Xiaoqing; Chi, Yawei; He, Tanjin

    2016-08-01

    Biodiesel contains a large proportion of unsaturated fatty acid methyl esters. Its combustion characteristics, especially its ignition behavior at low temperatures, have been greatly affected by these C═C double bonds. In this work, we performed a theoretical analysis of the effect of C═C double bonds on the low-temperature reactivity of alkenylperoxy radicals, the key intermediates from the low-temperature combustion of biodiesel. To understand how double bonds affect the fate of peroxy radicals, we selected three representative peroxy radicals from heptane, heptene, and heptadiene having zero, one, and two double C═C bonds, respectively, for study. The potential energy surfaces were explored at the CBS-QB3 level, and the reaction rate constants were computed using canonical/variational transition state theories. We have found that the double bond is responsible for the very different bond dissociation energies of the various types of C-H bonds, which in turn affect significantly the reaction kinetics of alkenylperoxy radicals. PMID:27404895

  6. The effect of gabapentin on muscle cramps during hemodialysis: A double-blind clinical trial.

    PubMed

    Beladi Mousavi, Seyed Seifollah; Zeraati, Abbasali; Moradi, Sajad; Mousavi, Marzieh Beladi

    2015-11-01

    Hemodialysis-associated muscle cramps (HAMC) are a common complication during hemodialysis (HD) sessions. A number of pharmacologic agents have been evaluated to prevent and or diminish HAMC; however, none of them has an established role. To the best of our knowledge, this is the first study to evaluate the possible effect of gabapentin on HAMC. In a double-blinded clinical trial, we compared the possible effect of gabapentin with a placebo in prevention and or diminishing episodes of HAMC in HD patients who had experienced frequent intradialytic muscle cramps. At first, placebo was given before each dialysis session for four weeks and then, after a two-week washout period, 300 mg of gabapentin was given before each dialysis session for four weeks to verify the effect of gabapentin on HAMC. Overall, 15 patients (seven men and eight women; mean age, 52.02 years) with frequent intradialytic muscle cramps were enrolled in the study. The incidence of symptomatic muscle cramp decreased in the gabapentin group compared with the placebo group, with a significant difference between them (P = 0.001). The intensity of muscle cramps also decreased in the gabapentin group (P = 0.001). There was no significant association between HAMC in male and female patients (P = 0. 397), mean age of HD patients (P = 0.226) and cause of end-stage renal disease (P = 0.551). According to the results of our study, gabapentin prescription before each HD session significantly reduced the frequency and the intensity of muscle cramps during HD without any major side-effects.

  7. Condensation heat transfer and pressure drop of R-134a saturated vapour inside a brazed compact plate fin heat exchanger with serrated fin

    NASA Astrophysics Data System (ADS)

    Ramana Murthy, K. V.; Ranganayakulu, C.; Ashok Babu, T. P.

    2016-05-01

    This paper presents the experimental heat transfer coefficient and pressure drop measured during R-134a saturated vapour condensation inside a small brazed compact plate fin heat exchanger with serrated fin surface. The effects of saturation temperature (pressure), refrigerant mass flux, refrigerant heat flux, effect of fin surface characteristics and fluid properties are investigated. The average condensation heat transfer coefficients and frictional pressure drops were determined experimentally for refrigerant R-134a at five different saturated temperatures (34, 38, 40, 42 and 44 °C). A transition point between gravity controlled and forced convection condensation has been found for a refrigerant mass flux around 22 kg/m2s. In the forced convection condensation region, the heat transfer coefficients show a three times increase and 1.5 times increase in frictional pressure drop for a doubling of the refrigerant mass flux. The heat transfer coefficients show weak sensitivity to saturation temperature (Pressure) and great sensitivity to refrigerant mass flux and fluid properties. The frictional pressure drop shows a linear dependence on the kinetic energy per unit volume of the refrigerant flow. Correlations are provided for the measured heat transfer coefficients and frictional pressure drops.

  8. Chemical vapour deposition of zeolitic imidazolate framework thin films

    NASA Astrophysics Data System (ADS)

    Stassen, Ivo; Styles, Mark; Grenci, Gianluca; Gorp, Hans Van; Vanderlinden, Willem; Feyter, Steven De; Falcaro, Paolo; Vos, Dirk De; Vereecken, Philippe; Ameloot, Rob

    2016-03-01

    Integrating metal-organic frameworks (MOFs) in microelectronics has disruptive potential because of the unique properties of these microporous crystalline materials. Suitable film deposition methods are crucial to leverage MOFs in this field. Conventional solvent-based procedures, typically adapted from powder preparation routes, are incompatible with nanofabrication because of corrosion and contamination risks. We demonstrate a chemical vapour deposition process (MOF-CVD) that enables high-quality films of ZIF-8, a prototypical MOF material, with a uniform and controlled thickness, even on high-aspect-ratio features. Furthermore, we demonstrate how MOF-CVD enables previously inaccessible routes such as lift-off patterning and depositing MOF films on fragile features. The compatibility of MOF-CVD with existing infrastructure, both in research and production facilities, will greatly facilitate MOF integration in microelectronics. MOF-CVD is the first vapour-phase deposition method for any type of microporous crystalline network solid and marks a milestone in processing such materials.

  9. Mapping of tritium emissions using absorption vapour samplers.

    PubMed

    Vodila, Gergely; Molnár, Mihály; Veres, Mihály; Svingor, Eva; Futó, István; Barnabás, István; Kapitány, Sándor

    2009-02-01

    Püspökszilágy Radioactive Waste Treatment and Disposal Facility (RWTDF) is a typical near-surface engineered repository designated to store low- and intermediate-level wastes from various institutes, research facilities and hospitals in Hungary. Two automatic combined (14)C-tritium sampling units installed at the facility sample the air 2 m above surface. The one installed near the vaults detects tritium (T) activities two orders of magnitude higher than the far reference sampling unit. To localize the T emissions, 19 small absorption vapour samplers filled with silica gel were settled onto the ground surface. After the saturation of the silica gel, the water was recovered and its T concentration was measured with a low-background liquid scintillation counter. The absorption vapour samplers are cheap, simple and easy-to-use. We present the samplers and the T distribution map constructed from the data, which helps to localize the T emission. PMID:19027205

  10. Effect of a Prebiotic Formulation on Frailty Syndrome: A Randomized, Double-Blind Clinical Trial

    PubMed Central

    Buigues, Cristina; Fernández-Garrido, Julio; Pruimboom, Leo; Hoogland, Aldert J.; Navarro-Martínez, Rut; Martínez-Martínez, Mary; Verdejo, Yolanda; Mascarós, Mari Carmen; Peris, Carlos; Cauli, Omar

    2016-01-01

    Aging can result in major changes in the composition and metabolic activities of bacterial populations in the gastrointestinal system and result in impaired function of the immune system. We assessed the efficacy of prebiotic Darmocare Pre® (Bonusan Besloten Vennootschap (BV), Numansdorp, The Netherlands) to evaluate whether the regular intake of this product can improve frailty criteria, functional status and response of the immune system in elderly people affected by the frailty syndrome. The study was a placebo-controlled, randomized, double blind design in sixty older participants aged 65 and over. The prebiotic product was composed of a mixture of inulin plus fructooligosaccharides and was compared with placebo (maltodextrin). Participants were randomized to a parallel group intervention of 13 weeks’ duration with a daily intake of Darmocare Pre® or placebo. Either prebiotic or placebo were administered after breakfast (between 9–10 a.m.) dissolved in a glass of water carefully stirred just before drinking. The primary outcome was to study the effect on frailty syndrome. The secondary outcomes were effect on functional and cognitive behavior and sleep quality. Moreover, we evaluated whether prebiotic administration alters blood parameters (haemogram and biochemical analysis). The overall rate of frailty was not significantly modified by Darmocare Pre® administration. Nevertheless, prebiotic administration compared with placebo significantly improved two frailty criteria, e.g., exhaustion and handgrip strength (p < 0.01 and p < 0.05, respectively). No significant effects were observed in functional and cognitive behavior or sleep quality. The use of novel therapeutic approaches influencing the gut microbiota–muscle–brain axis could be considered for treatment of the frailty syndrome. PMID:27314331

  11. Effect of a Prebiotic Formulation on Frailty Syndrome: A Randomized, Double-Blind Clinical Trial.

    PubMed

    Buigues, Cristina; Fernández-Garrido, Julio; Pruimboom, Leo; Hoogland, Aldert J; Navarro-Martínez, Rut; Martínez-Martínez, Mary; Verdejo, Yolanda; Mascarós, Mari Carmen; Peris, Carlos; Cauli, Omar

    2016-01-01

    Aging can result in major changes in the composition and metabolic activities of bacterial populations in the gastrointestinal system and result in impaired function of the immune system. We assessed the efficacy of prebiotic Darmocare Pre(®) (Bonusan Besloten Vennootschap (BV), Numansdorp, The Netherlands) to evaluate whether the regular intake of this product can improve frailty criteria, functional status and response of the immune system in elderly people affected by the frailty syndrome. The study was a placebo-controlled, randomized, double blind design in sixty older participants aged 65 and over. The prebiotic product was composed of a mixture of inulin plus fructooligosaccharides and was compared with placebo (maltodextrin). Participants were randomized to a parallel group intervention of 13 weeks' duration with a daily intake of Darmocare Pre(®) or placebo. Either prebiotic or placebo were administered after breakfast (between 9-10 a.m.) dissolved in a glass of water carefully stirred just before drinking. The primary outcome was to study the effect on frailty syndrome. The secondary outcomes were effect on functional and cognitive behavior and sleep quality. Moreover, we evaluated whether prebiotic administration alters blood parameters (haemogram and biochemical analysis). The overall rate of frailty was not significantly modified by Darmocare Pre(®) administration. Nevertheless, prebiotic administration compared with placebo significantly improved two frailty criteria, e.g., exhaustion and handgrip strength (p < 0.01 and p < 0.05, respectively). No significant effects were observed in functional and cognitive behavior or sleep quality. The use of novel therapeutic approaches influencing the gut microbiota-muscle-brain axis could be considered for treatment of the frailty syndrome. PMID:27314331

  12. A preliminary investigation of projectile shape effects in hypervelocity impact of a double-sheet structure

    NASA Technical Reports Server (NTRS)

    Morrison, R. H.

    1972-01-01

    Impact tests of a sphere and several cylinders of various masses and fineness ratios, all of aluminum, fired into an aluminum double-sheet structure at velocities near 7 km/sec, show that a cylinder, impacting in the direction of its axis, is considerably more effective as a penetrator than a sphere. Impacts of three cylinders of equal mass, but different fineness ratios, produced holes through the structures' rear sheet, whereas impact of a sphere of the same mass did not. Moreover, it was found that to prevent rear-sheet penetration, the mass of the 1/2-fineness-ratio cylinder had to be reduced by a factor greater than three. Further tests wherein the cylinder diameter was held constant while the cylinder length was systematically reduced showed that a cylinder with a fineness ratio of 0.07 and a mass of only 1/7 that of the sphere was still capable of producing a hole in the rear sheet.

  13. [Improvement of MRI effectiveness in the detection of intracerebral hematoma. Double inversion recovery].

    PubMed

    Burenchev, D V; Skvortsova, V I; Guseva, O I; Shumm, B A; Fomenkov, S A; Prokhorov, A V; Khetchikov, G V; Barkova, L A

    2009-01-01

    A study aimed at developing the pulse consequence, the double inversion recovery (DIR), using low field magnetic tomography, and assessing its effectiveness in the detection of intracerebral hematoma. The research has been conducted at "Ellipse" MR tomograph. The new pulse sequence has been created by the modification of the regular FLAIR, its technical parameters were as follows: the first TI - 90 ms, the second TI - 1300 ms, TR - 4665 ms, echo - 3. Twenty-seven patients have been enrolled in the study. The tissue contrast coefficients on FLAIR and DIR images have been compared. It has been shown that the contrast coefficient of normal brain structures and brain lesions on the DIR images in regard to the white matter are significantly higher than on the FLAIR images. Results of the study revealed that the dynamics of MR symptoms of intracerebral hematoma is faster on the DIR images compared to the FLAIR ones. This finding can be used for detection of intracerebral hematoma in difficult clinical cases.

  14. Edge effects in vertically-oriented graphene based electric double-layer capacitors

    NASA Astrophysics Data System (ADS)

    Yang, Huachao; Yang, Jinyuan; Bo, Zheng; Zhang, Shuo; Yan, Jianhua; Cen, Kefa

    2016-08-01

    Vertically-oriented graphenes (VGs) have been demonstrated as a promising active material for electric double-layer capacitors (EDLCs), partially due to their edge-enriched structure. In this work, the 'edge effects', i.e., edges as the promoters of high capacitance, in VG based EDLCs are investigated with experimental research and numerical simulations. VGs with diverse heights (i.e., edge-to-basal ratios) and edge densities are prepared with varying the plasma-enabled growth time and employing different plasma sources. Electrochemical measurements show that the edges play a predominant role on the charge storage behavior of VGs. A simulation is further conducted to unveil the roles of the edges on the separation and adsorption of ions within VG channels. The initial charge distribution of a VG plane is obtained with density functional theory (DFT) calculations, which is subsequently applied to a molecular dynamics (MD) simulation system to gain the insights into the microscope EDLC structures. Compared with the basal planes, the edges present higher initial charge density (by 4.2 times), higher ion packing density (by 2.6 times), closer ion packing location (by 0.8 Å), and larger ion separation degree (by 14%). The as-obtained findings will be instructive in designing the morphology and structure of VGs for enhanced capacitive performances.

  15. Edge effects in vertically-oriented graphene based electric double-layer capacitors

    NASA Astrophysics Data System (ADS)

    Yang, Huachao; Yang, Jinyuan; Bo, Zheng; Zhang, Shuo; Yan, Jianhua; Cen, Kefa

    2016-08-01

    Vertically-oriented graphenes (VGs) have been demonstrated as a promising active material for electric double-layer capacitors (EDLCs), partially due to their edge-enriched structure. In this work, the 'edge effects', i.e., edges as the promoters of high capacitance, in VG based EDLCs are investigated with experimental research and numerical simulations. VGs with diverse heights (i.e., edge-to-basal ratios) and edge densities are prepared with varying the plasma-enabled growth time and employing different plasma sources. Electrochemical measurements show that the edges play a predominant role on the charge storage behavior of VGs. A simulation is further conducted to unveil the roles of the edges on the separation and adsorption of ions within VG channels. The initial charge distribution of a VG plane is obtained with density functional theory (DFT) calculations, which is subsequently applied to a molecular dynamics (MD) simulation system to gain the insights into the microscope EDLC structures. Compared with the basal planes, the edges present higher initial charge density (by 4.2 times), higher ion packing density (by 2.6 times), closer ion packing location (by 0.8 Å), and larger ion separation degree (by 14%). The as-obtained findings will be instructive in designing the morphology and structure of VGs for enhanced capacitive performances.

  16. The double effects of silver nanoparticles on the PVDF membrane: Surface hydrophilicity and antifouling performance

    NASA Astrophysics Data System (ADS)

    Li, Jian-Hua; Shao, Xi-Sheng; Zhou, Qing; Li, Mi-Zi; Zhang, Qi-Qing

    2013-01-01

    In this study, silver nanoparticles were used to endow poly(vinylidene fluoride) (PVDF) membrane with excellent surface hydrophilicity and outstanding antifouling performance. Silver nanoparticles were successfully immobilized onto PVDF membrane surface under the presence of poly(acrylic acid) (PAA). The double effects of silver nanoparticles on PVDF membrane, i.e., surface hydrophilicity and anti-fouling performance, were systematically investigated. Judging from result of water static contact measurement, silver nanoparticles had provided a significant improvement in PVDF membrane surface hydrophilicity. And the possible explanation on the improvement of PVDF membrane surface hydrophilicity with silver nanoparticles was firstly proposed in this study. Membrane permeation and anti-bacterial tests were carried out to characterize the antifouling performance of PVDF membrane. Flux recovery ratio (FRR) increased about 40% after the presence of silver nanoparticles on the PVDF membrane surface, elucidating the anti-organic fouling performance of PVDF membrane was elevated by silver nanoparticles. Simultaneously, anti-bacterial test confirmed that PVDF membrane showed superior anti-biofouling activity because of silver nanoparticles. The above-mentioned results clarified that silver nanoparticles can endow PVDF membrane with both excellent surface hydrophilicity and outstanding antifouling performance in this study.

  17. The double effect of grain size on the work hardening behavior of polycrystalline copper

    SciTech Connect

    Gracio, J.J. . Dept. de Engenharia Mecanica)

    1994-08-15

    Following the approach by Ashby, one can consider that strain compatibility between adjacent grains of a polycrystal generates geometrical dislocations. These dislocations participated in the strengthening mechanism in conjunction with statistically stored dislocations which are related to the single-crystal behavior. The dislocations of either species are indistinguishable and, as a whole, they may contribute to cell formation. The dislocation structure formed in a polycrystal is then a function of the major or minor intergranular accommodation complexity. At intermediate strain values the accommodation is distributed over the cells leading to a linear relationship between the tensile stress and the inverse of the cell size, whatever the grain size of the tested samples. The aim of the present work is to check that the presence of statistical and geometrical dislocations in the grains, as well as the fact that at the very early stage of plastic deformation the mean free path of dislocations is of the order of the grain size, leads to a double effect of the grain size on the work hardening behavior of polycrystalline copper. Moreover, careful analysis of the mechanical behavior of polycrystalline copper, including the microstructural aspects of plastic deformation, is performed, allowing the understanding of the relationship between the work hardening ratio and the grain size.

  18. A 2-D semi-analytical model of double-gate tunnel field-effect transistor

    NASA Astrophysics Data System (ADS)

    Huifang, Xu; Yuehua, Dai; Ning, Li; Jianbin, Xu

    2015-05-01

    A 2-D semi-analytical model of double gate (DG) tunneling field-effect transistor (TFET) is proposed. By aid of introducing two rectangular sources located in the gate dielectric layer and the channel, the 2-D Poisson equation is solved by using a semi-analytical method combined with an eigenfunction expansion method. The expression of the surface potential is obtained, which is a special function for the infinite series expressions. The influence of the mobile charges on the potential profile is taken into account in the proposed model. On the basis of the potential profile, the shortest tunneling length and the average electrical field can be derived, and the drain current is then constructed by using Kane's model. In particular, the changes of the tunneling parameters Ak and Bk influenced by the drain—source voltage are also incorporated in the predicted model. The proposed model shows a good agreement with TCAD simulation results under different drain—source voltages, silicon film thicknesses, gate dielectric layer thicknesses, and gate dielectric layer constants. Therefore, it is useful to optimize the DG TFET and this provides a physical insight for circuit level design. Project supported by the National Natural Science Foundation of China (No. 61376106) and the Graduate Innovation Fund of Anhui University.

  19. Leidenfrost point and estimate of the vapour layer thickness

    NASA Astrophysics Data System (ADS)

    Gianino, Concetto

    2008-11-01

    In this article I describe an experiment involving the Leidenfrost phenomenon, which is the long lifetime of a water drop when it is deposited on a metal that is much hotter than the boiling point of water. The experiment was carried out with high-school students. The Leidenfrost point is measured and the heat laws are used to estimate the thickness of the vapour layer, d≈0.06 mm, which prevents the drop from touching the hotplate.

  20. 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.

  1. Facebook and its effects on users' empathic social skills and life satisfaction: a double-edged sword effect.

    PubMed

    Chan, Terri H

    2014-05-01

    This study examines how Facebook usage affects individual's empathic social skills and life satisfaction. Following the self-presentational theory, the study explores a key component of the Internet paradox-whether Facebook suppresses or enhances users' interpersonal competence (specifically empathic social skills), given their respective personality makeup. Going further, the study assesses these events' subsequent impacts on users' psychological well-being. Analogous to a double-edged sword, Facebook activities are hypothesized to suppress the positive effect of a user's extraversion orientation on empathic social skills but lessen the negative effect of neuroticism on these skills. The study examines a sample of college-aged Facebook users (n=515), who responded to a large-scale online survey. The findings from a structural equation modeling analysis indicate that while empathic social skills are positively associated with life satisfaction, Facebook activities mainly exert suppression effects. Only upon low usage can Facebook activities lessen the negative effect of neuroticism on empathic social skills, suggesting that Facebook may appear as a less threatening platform for social interactions among neurotics. Yet, results in general suggest that undesirable effects may occur at high levels of Facebook usage whereby both extroverted and neurotic users displace real world social ties to online ones. The findings point to the complex ways in which social media usage may impact the livelihood of users.

  2. Facebook and its effects on users' empathic social skills and life satisfaction: a double-edged sword effect.

    PubMed

    Chan, Terri H

    2014-05-01

    This study examines how Facebook usage affects individual's empathic social skills and life satisfaction. Following the self-presentational theory, the study explores a key component of the Internet paradox-whether Facebook suppresses or enhances users' interpersonal competence (specifically empathic social skills), given their respective personality makeup. Going further, the study assesses these events' subsequent impacts on users' psychological well-being. Analogous to a double-edged sword, Facebook activities are hypothesized to suppress the positive effect of a user's extraversion orientation on empathic social skills but lessen the negative effect of neuroticism on these skills. The study examines a sample of college-aged Facebook users (n=515), who responded to a large-scale online survey. The findings from a structural equation modeling analysis indicate that while empathic social skills are positively associated with life satisfaction, Facebook activities mainly exert suppression effects. Only upon low usage can Facebook activities lessen the negative effect of neuroticism on empathic social skills, suggesting that Facebook may appear as a less threatening platform for social interactions among neurotics. Yet, results in general suggest that undesirable effects may occur at high levels of Facebook usage whereby both extroverted and neurotic users displace real world social ties to online ones. The findings point to the complex ways in which social media usage may impact the livelihood of users. PMID:24606026

  3. Double-edged effects of arsenic compounds: anticancer and carcinogenic effects.

    PubMed

    Rehman, Kanwal; Naranmandura, Hua

    2013-12-01

    Although arsenic is known to cause cancers of lung, skin and kidney, arsenic trioxide (As2O3) has been recently recognized as one of the most effective novel anticancer agent for the treatment of acute promyelocytic leukemia (APL). These paradoxical effects of arsenic may be dose-dependent, associated with its distinctive metabolism, or correlated with its direct or indirect effects on different cellular pathways which may result in altered cellular functions. The basic mechanism through which As2O3 induces molecular remission in APL patients include direct targeting of PML and retinoic acid receptor alpha fusion protein (PML-RARα) by arsenic resulting in oncoprotein degradation leading to partial differentiation. Many in vitro studies have also indicated that the anticancer properties of As2O3 against non-APL blood cancers predominantly occur through induction of apoptotic pathway. Especially, release of cytochrome c or activation of the caspase cascades and apoptosis-related proteins by arsenic is thought to occur by directly targeting mitochondria. The mechanisms and the selective target sites that have been usually associated with the cytotoxic effects of arsenicals are discussed here with reference to their contribution towards the anticancer properties of arsenic. In this review we have particularly explained the in vivo or in vitro arsenic toxicity based on arsenic metabolic pathway and its different metabolites. These multiple effects and different selective target sites for arsenic and its metabolites emphasize the need for better understanding of paradoxical effects of arsenic which may provide the appropriate use of this agent in the treatment of various malignancies. PMID:24164099

  4. Double-edged effects of arsenic compounds: anticancer and carcinogenic effects.

    PubMed

    Rehman, Kanwal; Naranmandura, Hua

    2013-12-01

    Although arsenic is known to cause cancers of lung, skin and kidney, arsenic trioxide (As2O3) has been recently recognized as one of the most effective novel anticancer agent for the treatment of acute promyelocytic leukemia (APL). These paradoxical effects of arsenic may be dose-dependent, associated with its distinctive metabolism, or correlated with its direct or indirect effects on different cellular pathways which may result in altered cellular functions. The basic mechanism through which As2O3 induces molecular remission in APL patients include direct targeting of PML and retinoic acid receptor alpha fusion protein (PML-RARα) by arsenic resulting in oncoprotein degradation leading to partial differentiation. Many in vitro studies have also indicated that the anticancer properties of As2O3 against non-APL blood cancers predominantly occur through induction of apoptotic pathway. Especially, release of cytochrome c or activation of the caspase cascades and apoptosis-related proteins by arsenic is thought to occur by directly targeting mitochondria. The mechanisms and the selective target sites that have been usually associated with the cytotoxic effects of arsenicals are discussed here with reference to their contribution towards the anticancer properties of arsenic. In this review we have particularly explained the in vivo or in vitro arsenic toxicity based on arsenic metabolic pathway and its different metabolites. These multiple effects and different selective target sites for arsenic and its metabolites emphasize the need for better understanding of paradoxical effects of arsenic which may provide the appropriate use of this agent in the treatment of various malignancies.

  5. The influence of low concentrations of irritants on skin barrier function as determined by water vapour loss.

    PubMed

    van der Valk, P G; Nater, J P; Bleumink, E

    1985-01-01

    The effect of some irritants on the barrier function of the skin was assessed by means of water vapour loss measurements. 100 microliter of the test substance in distilled water were applied to the skin for a period of 48 h, using large Finn chambers. The exposures were done in a test panel of 42 subjects. Sodium lauryl sulfate (2%), cocobetaine (2%), crotonaldehyde (0.75%) with sodium lauryl sulfate (0.5%) and dimethyl sulfoxide (50%) markedly influenced water vapour loss. Sodium hydroxide (1%) had less effect on water vapour loss, although the increase was significant (p less than 0.05). Phenol (5%) and benzalkonium chloride (0.2%) did not significantly influence the loss of water through the skin. It is concluded that subclinical effects of chemicals on the barrier function may be of importance in the development of irritant contact dermatitis, but that this capacity is probably not the only factor which determines the potential of a substance to contribute to the development of irritant contact dermatitis. A chemical which has little or no effect on the function of the horny layer may have a toxic effect on the viable cells of deeper layers of the skin. This toxic effect may also be an important subclinical factor in the development of irritant contact dermatitis.

  6. The excitonic effects in single and double-walled boron nitride nanotubes

    SciTech Connect

    Wang, Shudong; Li, Yunhai; Wang, Jinlan; Yip, Joanne

    2014-06-28

    The electronic structures and excitonic optical properties of single- and double-walled armchair boron nitride nanotubes (BNNTs) [e.g., (5,5) and (10,10), and (5,5)@(10,10)] are investigated within many-body Green's function and Bethe-Salpeter equation formalism. The first absorption peak of the double-walled nanotube has almost no shift compared with the single-walled (5,5) tube due to the strong optical transition in the double-walled tube that occurs within the inner (5,5) one. Dark and semi-dark excitonic states are detected in the lower energy region, stemming from the charge transfer between inner and outer tubes in the double-walled structure. Most interestingly, the charge transfer makes the electron and the hole reside in different tubes. Moreover, the excited electrons in the double-walled BNNT are able to transfer from the outer tube to the inner one, opposite to that which has been observed in double-walled carbon nanotubes.

  7. 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

  8. The Effects of Doubling Instruction Efforts on Middle School Students' Achievement: Evidence from a Multiyear Regression-Discontinuity Design. Upjohn Institute Working Paper No. 14-205

    ERIC Educational Resources Information Center

    Bartik, Timothy J.; Lachowska, Marta

    2014-01-01

    We use a regression-discontinuity design to study the effects of double blocking sixth-grade students in reading and mathematics on their achievement across three years of middle school. To identify the effect of the intervention, we use sharp cutoffs in the test scores used to assign students to double blocking. We find large, positive, and…

  9. 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

  10. Flow and forced-convection heat transfer over forward-facing double steps (effects of step ratio)

    SciTech Connect

    Shakouchi, Toshihiko; Kajino, Itsuki

    1994-07-01

    The flow and heat transfer over a step (a forward- or backward-facing step) result in complicated flow conditions, such as a shear flow field, flow separation, and generation of vortices, and provide some interesting information that improves understanding of the heat transfer on the surface. This is a very frequent flow, and basic to various kinds of chemical equipment, fluid machinery, combustion furnaces, and IC-packages. Recently, there have been many studies on this flow situation by numerical analysis, measurement of mean and fluctuating velocities within the separation bubble using laser Doppler anemometer, and heat transfer analysis. A flow passage having two steps in tiers (forward- or backward-facing double steps) is also frequent, and it is very important to clarify the effects of each step on the flow and the heat-transfer characteristics. This however, has not yet been investigated. This study presents the results of an experimental investigation on the flow and forced convective heat transfer over forward-facing single and double steps. Measurements of velocity and turbulence intensity, flow visualization, pressure distribution, and heat transfer over forward-facing double steps were carried out for various step ratios, L/a (L: step length, a: step height). From these results, the effects of the step ratio on the flow and heat-transfer characteristics were clarified and the following results were confirmed. Heat-transfer enhancement of a double step is considerable compared with that of a single step or a flat plate.

  11. Strain and structure heterogeneity in MoS2 atomic layers grown by chemical vapour deposition.

    PubMed

    Liu, Zheng; Amani, Matin; Najmaei, Sina; Xu, Quan; Zou, Xiaolong; Zhou, Wu; Yu, Ting; Qiu, Caiyu; Birdwell, A Glen; Crowne, Frank J; Vajtai, Robert; Yakobson, Boris I; Xia, Zhenhai; Dubey, Madan; Ajayan, Pulickel M; Lou, Jun

    2014-11-18

    Monolayer molybdenum disulfide (MoS2) has attracted tremendous attention due to its promising applications in high-performance field-effect transistors, phototransistors, spintronic devices and nonlinear optics. The enhanced photoluminescence effect in monolayer MoS2 was discovered and, as a strong tool, was employed for strain and defect analysis in MoS2. Recently, large-size monolayer MoS2 has been produced by chemical vapour deposition, but has not yet been fully explored. Here we systematically characterize chemical vapour deposition-grown MoS2 by photoluminescence spectroscopy and mapping and demonstrate non-uniform strain in single-crystalline monolayer MoS2 and strain-induced bandgap engineering. We also evaluate the effective strain transferred from polymer substrates to MoS2 by three-dimensional finite element analysis. Furthermore, our work demonstrates that photoluminescence mapping can be used as a non-contact approach for quick identification of grain boundaries in MoS2.

  12. [Carbon sequestration effects of rice straw return in double season paddy field in Southern China].

    PubMed

    Wu, Jia-Mei; Ji, Xiong-Hui; Peng, Hua; Shi, Li-Hong; Liu, Zhao-Bing; Tian, Fa-Xiang; Huo, Lian-Jie; Zhu, Jian

    2011-12-01

    In a long-term site-specific experiment with rice straw return (RSR) and in a short-term experiment with different RSR modes, this paper studied the effects of RSR on the soil organic carbon (SOC) sequestration, methane emission, and net carbon sink in a double season paddy field. RSR increased the SOC content, and the annual increasing rate of soil carbon sink in plow layer (0-15 cm) under long-term RSR was 0.07 t C x hm(-2) x a(-1). With the increasing amount of RSR, the apparent SOC transformation rate decreased. RSR promoted the methane emission from the paddy field significantly, and the methane emission flux in treatment RSR plus NPK during early- and late rice growth seasons increased by 75.0% and 251.5% (P < 0.01), respectively, compared with that in treatment NPK. The methane emission increased with the increasing amount of RSR. Under the similar tillage mode and rice yield, the rice straw returned had the similar apparent methane transformation rate. Considering the soil carbon sequestration and the net carbon sink after methane emission in the paddy field comprehensively, treatment RSR plus NPK had significant negative effect on the carbon sink which was basically approached to the bio-fixation of carbon by rice and increased by 158.3%, as compared with treatment NPK. Among different RSR modes, rice straw mulching plus no tillage decreased soil methane emission significantly, with the net carbon sink decreased by 50.9% as compared with the treatment high stubble plus tillage, and benefited the high and stable yielding of rice. PMID:22384587

  13. Enhancing and suppressing effects of an inner droplet on deformation of a double emulsion droplet under shear.

    PubMed

    Chen, Yongping; Liu, Xiangdong; Zhang, Chengbin; Zhao, Yuanjin

    2015-03-01

    We combine experimental investigation with numerical simulation to explore fundamental hydrodynamic effects of an inner droplet on deformation of a double emulsion droplet under shear. The transient deformation oscillation is found to be intensified by the inner droplet. Especially, we demonstrate that the double emulsion droplet can exhibit both larger and smaller steady deformation than the single-phase droplet, which arises from the competition between the coexisting enhancing and suppressing effects by the inner droplet on the deformation. We further provide a regime diagram to quantitatively recognize the respective dominant regime of these two effects, depending on the capillary number and radius ratio of the inner droplet to the outer one. PMID:25589363

  14. Layered double hydroxide formation in Bayer liquor and its promotional effect on oxalate precipitation

    SciTech Connect

    Perrotta, A.J.; Williams, F.

    1996-10-01

    Enhancing the precipitation of sodium oxalate from Bayer process liquor to improve the quality of alumina product remains an important objective for Bayer refining. The formation of layered double hydroxides by the reaction of alkaline earth oxides, such as lime and magnesia, with Bayer liquor gives a crystal structure which is capable of intercalating anions, both inorganic and organic, within its structure. Both lime and magnesia, with long contact times in Bayer liquor, show layered double hydroxide formation. This layered double hydroxide formation is accompanied with a decrease in the sodium oxalate content in the liquor from about 3 g/L to below 1 g/L. Short contact times lead to a destabilization of the liquor which facilitates sodium oxalate precipitation. Additional work on magnesium hydroxide shows, in comparison to lime and magnesia, much less layered double hydroxide formation with equivalent residence time in the liquor. Destabilization of the liquor also occurs, giving enhanced oxalate precipitation with less alumina being consumed in agreement with lower layered double hydroxide formation. Thermal regeneration of these structures, followed by in-situ recrystallization in Bayer liquor, also gives enhanced oxalate precipitation, suggesting that there is an opportunity for a regenerable oxalate reduction system. The implementation of these experiments and other related technology into the plant has resulted in the Purox Process for enhancing the precipitation of sodium oxalate from Bayer liquor.

  15. Investigation of wave propagation in double cylindrical rods considering the effect of prestress

    NASA Astrophysics Data System (ADS)

    Li, Chunlei; Han, Qiang; Liu, Yijie; Liu, Xiucheng; Wu, Bin

    2015-09-01

    This paper presents the investigation of guided wave propagation in prestressed double-cylinder structure. Based on Hertzian contact theory, the interaction between two rods is treated as a plane strain problem and the stress state in the waveguide under the static load is obtained. The stress state is considered as a prestressed configuration for elastic wave propagation analysis in double cylindrical rods. The elastodynamic equation of the prestressed structure is established with the updated Lagrangian formulation and the wave finite element (WFE) method. Firstly, the equation is verified by the application on an aluminum rod compared with the Euler-Bernoulli beam theory. Then, dispersion curves for single rod and double cylindrical rods without prestress are computed. Besides, at the dimensionless frequency 0.25 the propagating modes in double cylindrical rods are identified with mode shapes and displacement vectors. The guided waves in double rods consist of the modes different from single rod. Particularly, there exist two kinds of torsional-like modes, one of which has a twist center and the other has two. The latter changes obviously with the increase of prestress in the waveguide. At low frequencies, torsional-like modes are very sensitive to the variation of prestress; in addition, the prestress configuration has little influence on propagating modes at mid-frequencies but some at high frequencies.

  16. Quantum Mechanical Effects on the Threshold Voltage of Double-Gate Metal-Oxide-Semiconductor Field-Effect Transistors

    NASA Astrophysics Data System (ADS)

    Hu, Guang-Xi; Liu, Ran; Qiu, Zhi-Jun; Wang, Ling-Li; Tang, Ting-Ao

    2010-03-01

    A model for a metal-oxide-semiconductor field-effect transistor (MOSFET) with a double gate (DG) is developed. Quantum mechanical effects on the threshold voltage (VTH) are modeled and investigated analytically. The analytic model shows how VTH is increased with quantum mechanical effect. The model is applicable to both symmetric DG (SDG) and asymmetric DG (ADG) nMOSFETs, and is also applicable to both doped and undoped DG nMOSFETs. The analytic results are verified by comparing with the results obtained from simulations using Schred, and good agreement is observed. The VTH of an ADG nMOSFET will shift more than that of an SDG nMOSFET, and the VTH of a DG transistor with (110)-silicon (Si) orientation will shift more than that of a DG transistor with (100)-Si orientation. When the silicon thickness tsi < 3 nm, the VTH shift will be significant, and one should be careful in the use of an extremely thin silicon body. When the body doping density (NA) is not high (<1018 cm-3), the VTH shift is almost the same for different NA. When NA > 1018 cm-3, the higher the NA, the more the VTH shift.

  17. Vapour-liquid phase diagram for an ionic fluid in a random porous medium.

    PubMed

    Holovko, M F; Patsahan, O; Patsahan, T

    2016-10-19

    We study the vapour-liquid phase behaviour of an ionic fluid confined in a random porous matrix formed by uncharged hard sphere particles. The ionic fluid is modelled as an equimolar binary mixture of oppositely charged equisized hard spheres, the so-called restricted primitive model (RPM). Considering the matrix-fluid system as a partly-quenched model, we develop a theoretical approach which combines the method of collective variables with the extension of the scaled-particle theory (SPT) for a hard-sphere fluid confined in a disordered hard-sphere matrix. The approach allows us to formulate the perturbation theory using the SPT for the description of the thermodynamics of the reference system. The phase diagrams of the RPM in matrices of different porosities and for different size ratios of matrix and fluid particles are calculated in the random-phase approximation and also when the effects of higher-order correlations between ions are taken into account. Both approximations correctly reproduce the basic effects of porous media on the vapour-liquid phase diagram, i.e. with a decrease of porosity the critical point shifts towards lower fluid densities and lower temperatures and the coexistence region gets narrower. For the fixed matrix porosity, both the critical temperature and the critical density increase with an increase of size of matrix particles and tend to the critical values of the bulk RPM. PMID:27548356

  18. Vapour-liquid phase diagram for an ionic fluid in a random porous medium

    NASA Astrophysics Data System (ADS)

    Holovko, M. F.; Patsahan, O.; Patsahan, T.

    2016-10-01

    We study the vapour-liquid phase behaviour of an ionic fluid confined in a random porous matrix formed by uncharged hard sphere particles. The ionic fluid is modelled as an equimolar binary mixture of oppositely charged equisized hard spheres, the so-called restricted primitive model (RPM). Considering the matrix-fluid system as a partly-quenched model, we develop a theoretical approach which combines the method of collective variables with the extension of the scaled-particle theory (SPT) for a hard-sphere fluid confined in a disordered hard-sphere matrix. The approach allows us to formulate the perturbation theory using the SPT for the description of the thermodynamics of the reference system. The phase diagrams of the RPM in matrices of different porosities and for different size ratios of matrix and fluid particles are calculated in the random-phase approximation and also when the effects of higher-order correlations between ions are taken into account. Both approximations correctly reproduce the basic effects of porous media on the vapour-liquid phase diagram, i.e. with a decrease of porosity the critical point shifts towards lower fluid densities and lower temperatures and the coexistence region gets narrower. For the fixed matrix porosity, both the critical temperature and the critical density increase with an increase of size of matrix particles and tend to the critical values of the bulk RPM.

  19. The effect of flexible magnets on hand muscle strength: a randomized, double-blind study.

    PubMed

    Chaloupka, Edward C; Kang, Jie; Mastrangelo, M Alysia

    2002-02-01

    The purpose of this study was to determine the effect of a flexible magnet on hand grip and thumb-forefinger pinch strength. Flexible magnet use has become popular in sports medicine and rehabilitation for a number of reasons, including augmenting muscle force output. Thirty-five university students (18 men and 17 women) volunteered for this study. Each subject was tested for grip strength (grip dynamometer) and thumb-forefinger pinch strength (pinch gauge) under 3 different treatment conditions: baseline (no magnet), sham magnet (placebo), and flexible magnet (700-G intensity). The order of treatments was randomly assigned, and all data collection followed a double-blind format. For grip strength measurements, magnet placement was over the bellies of the flexor digitorum profundus and flexor digitorum superficialis, and for pinch strength measurements, it was over the bellies of the flexor pollicis brevis and opponens pollicis. Three trials for each strength measurement for each of the 3 conditions were performed. Magnets (700 G or sham) were placed on the appropriate areas of the skin 3 minutes before the first test trial, with each subsequent test trial separated by 1 minute. Comparison among the 3 treatment conditions was analyzed using a 1-way analysis of variance (ANOVA) with repeated measures. ANOVA revealed no statistically significant (p > 0.05) mean differences for strength among any of the 3 treatments (baseline, 700-G magnet, or sham magnet) for either hand grip or thumb-forefinger pinch within each sex subgroup or for the combined group. The findings indicate that flexible magnets with a field strength of 700 G do not increase muscle strength.

  20. [Effect of moderate salt restriction on the antihypertensive action of nifedipine: a double blind study].

    PubMed

    Del Río, A; Rodríguez-Villamil, J L; López-Campos, J M; Carrera, F

    1990-01-01

    Moderate salt restriction is of debatable efficacy in the treatment of mild or moderate hypertension; however, salt restriction enhances the activity of most antihypertensive drugs. Some observations suggest that the antihypertensive activity of calcium antagonists is not increased or could even decrease with dietary salt restriction. In the present work 15 patients suffering arterial hypertension and normal renal function are studied during four two week periods; a) unrestricted diet and medication, b) unrestricted diet and nifedipine (40 mg/day), c) low salt diet (5 g of salt/day) and nifedipine, and d) the same low salt diet, nifedipine and a salt supplement (6 g/day); salt or placebo were given in a double blind manner. At the end of each period arterial blood pressure was recorded, a urine sample for sodium determination was taken, and a blood sample was drawn for serum renine activity and biochemical parameters; at the end of each period patients' weight was recorded. Blood pressure significantly decreased (systolic: 9.83%, and dyastolic 11.17%) in patients treated with nifedipine, with no differences observed with salt modifications. Urinary sodium reflected correctly dietary salt modifications. Serum renine activity significantly increased during salt restriction. No significant changes were observed in weight or in the biochemical parameters studied. These results seem to suggest that the antihypertensive effect of nifedipine in patents suffering mild to moderate essential hypertension, with no change observed is not altered by the amount of salt in diet, at least within the limits studied (89.7 to 190 mEq/day of Sodium).

  1. Double space with double line

    SciTech Connect

    Cheltsov, I A

    2004-10-31

    For a singular double cover of P{sup 3} ramified in a sextic with double line, its birational maps into Fano 3-folds with canonical singularities, elliptic fibrations, and fibrations on surfaces of Kodaira dimension zero are described.

  2. Double space with double line

    NASA Astrophysics Data System (ADS)

    Cheltsov, I. A.

    2004-10-01

    For a singular double cover of \\mathbb P^3 ramified in a sextic with double line, its birational maps into Fano 3-folds with canonical singularities, elliptic fibrations, and fibrations on surfaces of Kodaira dimension zero are described.

  3. [Double teeth].

    PubMed

    Schuurs, A H B; van Loveren, C

    2002-04-01

    Double teeth are not really rare, but it is still enigmatic why and how they develop. Based upon the clinical, morphological and anatomical appearance and the number of teeth in mouths with double teeth, the double teeth are labelled as products of 'fusion' and 'clefting', but the criteria to attach such etiological names are lacking. It is assumed that heredity is involved in the development of double teeth. Therefore it is attempted to explain why only one of a homozygotic twin had a double tooth. PMID:11982209

  4. Effect of an Echinacea-Based Hot Drink Versus Oseltamivir in Influenza Treatment: A Randomized, Double-Blind, Double-Dummy, Multicenter, Noninferiority Clinical Trial

    PubMed Central

    Rauš, Karel; Pleschka, Stephan; Klein, Peter; Schoop, Roland; Fisher, Peter

    2015-01-01

    Background Echinacea has antiviral activity against influenza viruses in vitro and has traditionally been used for treatment of colds and flu. Objectives This randomized, double-blind, double-dummy, multicenter, controlled clinical trial compared a new echinacea formulation with the neuraminidase inhibitor oseltamivir, the gold standard treatment for influenza. Methods Following informed consent, 473 patients with early influenza symptoms (≤48 hours) were recruited in primary care in the Czech Republic and randomized to either 5 days of oseltamivir followed by 5 days of placebo, or 10 days of an Echinacea purpurea-based formulation called Echinaforce Hotdrink (A. Vogel Bioforce AG, Roggwil, Switzerland). The proportion of recovered patients (influenza symptoms rated as absent or mild in the evening) was analyzed for noninferiority between treatment groups using a generalized Wilcoxon test with significance level α = 0.05 (2-sided) and using a CI approach in the per-protocol sample. Results Recovery from illness was comparable in the 2 treatment groups at 1.5% versus 4.1% after 1 day, 50.2% versus 48.8% after 5 days, and 90.1% versus 84.8% after 10 days of treatment with Echinaforce Hotdrink and oseltamivir, respectively. Noninferiority was demonstrated for each day and overall (95% CI, 0.487–0.5265 by generalized Wilcoxon test). Very similar results were obtained in the group with virologically confirmed influenza virus infections and in a retrospective analysis during the peak influenza period. The incidence of complications was lower with Echinaforce Hotdrink than with oseltamivir (2.46% vs 6.45%; P = 0.076) and fewer adverse events (particularly nausea and vomiting) were observed with Echinaforce Hotdrink. Conclusions Echinaforce Hotdrink is as effective as oseltamivir in the early treatment of clinically diagnosed and virologically confirmed influenza virus infections with a reduced risk of complications and adverse events. It appears to be an attractive

  5. Non-Abelian Josephson Effect between Two F=2 Spinor Bose-Einstein Condensates in Double Optical Traps

    SciTech Connect

    Qi Ran; Liu, W. M.; Yu, Xiao-Lu; Li, Z. B.

    2009-05-08

    We investigate the non-Abelian Josephson effect in F=2 spinor Bose-Einstein condensates with double optical traps. We propose a real physical system which contains non-Abelian Josephson effect and has very different density and spin tunneling characters compared with the Abelian case. We calculate the frequencies of the pseudo Goldstone modes in different phases between two traps, respectively, which are the crucial feature of the non-Abelian Josephson effect. We also give an experimental protocol to observe this novel effect in future experiments.

  6. Effects of external and gap mean flows on sound transmission through a double-wall sandwich panel

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Sebastian, Alexis

    2015-05-01

    This paper studies analytically the effects of an external mean flow and an internal gap mean flow on sound transmission through a double-wall sandwich panel lined with poroelastic materials. Biot's theory is employed to describe wave propagation in poroelastic materials, and the transfer matrix method with three types of boundary conditions is applied to solve the system simultaneously. The random incidence transmission loss in a diffuse field is calculated numerically, and the limiting angle of incidence due to total internal reflection is discussed in detail. The numerical predictions suggest that the sound insulation performance of such a double-wall panel is enhanced considerably by both external and gap mean flows particularly in the high-frequency range. Similar effects on transmission loss are observed for the two mean flows. It is shown that the effect of the gap mean flow depends on flow velocity, flow direction, gap depth and fluid properties and also that the fluid properties within the gap appear to influence the transmission loss more effectively than the gap flow. Despite the implementation difficulty in practice, an internal gap flow provides more design space for tuning the sound insulation performance of a double-wall sandwich panel and has great potential for active/passive noise control.

  7. Effects of radial diffuser hydraulic design on a double-suction centrifugal pump

    NASA Astrophysics Data System (ADS)

    Hou, H. C.; Zhang, Y. X.; Xu, C.; Zhang, J. Y.; Li, Z. L.

    2016-05-01

    In order to study effects of radial diffuser on hydraulic performance of crude oil pump, the steady CFD numerical method is applied and one large double-suction oil pump running in long-distance pipeline is considered. The research focuses on analysing the influence of its diffuser vane profile on hydraulic performance of oil pump. The four different types of cylindrical vane have been designed by in-house codes mainly including double arcs (DA), triple arcs (TA), equiangular spiral line (ES) and linear variable angle spiral line (LVS). During design process diffuser vane angles at inlet and outlet are tentatively given within a certain range and then the wrapping angle of the four types of diffuser vanes can be calculated automatically. Under the given inlet and outlet angles, the linear variable angle spiral line profile has the biggest wrapping angle and profile length which is good to delay channel diffusion but bring more friction hydraulic loss. Finally the vane camber line is thickened at the certain uniform thickness distribution and the 3D diffuser models are generated. The whole flow passage of oil pump with different types of diffusers under various flow rate conditions are numerically simulated based on RNG k-ɛ turbulent model and SIMPLEC algorithm. The numerical results show that different types of diffusers can bring about great difference on the hydraulic performance of oil pump, of which the ES profile diffuser with its proper setting angle shows the best hydraulic performance and its inner flow field is improved obviously. Compared with the head data from model sample, all designed diffusers can make a certain improvement on head characteristic. At the large flow rate conditions the hydraulic efficiency increases obviously and the best efficiency point shift to the large flow rate range. The ES profile diffuser embodies the better advantages on pump performance which can be explained theoretically that the diffuser actually acts as a diffusion

  8. Tracing the interwell plasmon in a grid-gated double-quantum-well field-effect transistor

    NASA Astrophysics Data System (ADS)

    Popov, Vyacheslav V.; Teperik, Tatiana V.; Zayko, Yuriy N.; Horing, Norman J. M.; Fateev, Denis V.

    2005-06-01

    The terahertz (THz) absorption spectra of plasmon modes in a grid-gated double-quantum-well (DQW) field-effect transistor (FET) structute is analyzed theoretically and numerically using the scattering matrix approach and is shown to faithfully reproduce strong resonant features of recent experimental observations of THz photoconductivity in such a structure. No traces ofthe interwell plasmon is found in THz absorption spectra.

  9. [A double-blind study on the effect of dexetimide in the control of neuroleptic-induced extrapyramidal side-effects].

    PubMed

    Chen, Y

    1991-08-01

    A double-blind study was carried out on the therapeutic effects of dexetimide and artane in the control of neuroleptic-induced extrapyramidal side-effects in 261 cases of schizophrenia. The authors found that therapeutic effects of two drugs for the control of extrapyramidal signs were equal. Dexetimidal had the advantages of less side-effects, less dosage and long-action. PMID:1683277

  10. The role of water vapour in the orientation behaviour of the blood-sucking bug Triatoma infestans (Hemiptera, Reduviidae).

    PubMed

    Barrozo, R B; Manrique, G; Lazzari, C R

    2003-04-01

    The behavioural response to water vapour of the haematophagous bug Triatoma infestans was analysed. Dry or humid discrete sources at different temperatures were used as stimuli for insects walking on a locomotion compensator. Humidity significantly increased the tendency of these bugs to orientate towards thermal sources. Furthermore, humid sources at room temperature were attractive to T. infestans, but this effect was limited to short-range distances. On the other hand, dynamic sources, i.e. airstreams carrying different water vapour contents did not affect the spontaneous anemotactic behaviour of this species, neither in sign (positive) nor in intensity. The anemotactic behaviour was also not influenced by the physiological water balance state of the bugs. Results are discussed in relation to the cues released by living hosts of triatomine bugs and in relation to their responses to air-currents.

  11. Study of water vapour permeability of protein and gum-based edible films by a photothermal method

    NASA Astrophysics Data System (ADS)

    Tomás, S. A.; Saavedra, R.; Cruz, A.; Pedroza-Islas, R.; San Martín, E.

    2005-06-01

    The water vapour permeability of protein and gum-based edible films was studied by means of a photothermal method. The films were prepared with two basic ingredients, whey protein concentrate and mesquite gum, according to the proportions 75:25, 50:50, 25:75, and 0:100 (weight:weight). The water vapour diffusion coefficient of the analyzed films was found within the interval 0.37 × 10-6 to 2.04 × 10-6 cm^2/s, increasing linearly by increasing the mesquite gum composition in the films. The incorporation of mesquite gum in films produces less effective moisture barriers due to its highly hydrophilic property.

  12. Cation ordering and effect of biaxial strain in double perovskite CsRbCaZnCl6

    DOE PAGES

    Pilania, G.; Uberuaga, B. P.

    2015-03-19

    Here, we investigate the electronic structure, energetics of cation ordering, and effect of biaxial strain on double perovskite CsRbCaZnCl6 using first-principles calculations based on density functional theory. The two constituents (i.e., CsCaCl3 and RbZnCl3) forming the double perovskite exhibit a stark contrast. While CsCaCl3 is known to exist in a cubic perovskite structure and does not show any epitaxial strain induced phase transitions within an experimentally accessible range of compressive strains, RbZnCl3 is thermodynamically unstable in the perovskite phase and exhibits ultra-sensitive response at small epitaxial strains if constrained in the perovskite phase. We show that combining the two compositionsmore » in a double perovskite structure not only improves overall stability but also the strain-polarization coupling of the material. Our calculations predict a ground state with P4/nmm space group for the double perovskite, where A-site cations (i.e., Cs and Rb) are layer-ordered and B-site cations (i.e., Ca and Zn) prefer a rocksalt type ordering. The electronic structure and bandgap in this system are shown to be quite sensitive to the B-site cation ordering and is minimally affected by the ordering of A-site cations. We find that at experimentally accessible compressive strains CsRbCaZnCl6 can be phase transformed from its paraelectric ground state to an antiferroelectric state, where Zn atoms contribute predominantly to the polarization. Furthermore, both energy difference and activation barrier for a transformation between this antiferroelectric state and the corresponding ferroelectric configuration are predicted to be small. As a result, the computational approach presented here opens a new pathway towards a rational design of novel double perovskites with improved strain response and functionalities.« less

  13. Cation ordering and effect of biaxial strain in double perovskite CsRbCaZnCl6

    SciTech Connect

    Pilania, G.; Uberuaga, B. P.

    2015-03-19

    Here, we investigate the electronic structure, energetics of cation ordering, and effect of biaxial strain on double perovskite CsRbCaZnCl6 using first-principles calculations based on density functional theory. The two constituents (i.e., CsCaCl3 and RbZnCl3) forming the double perovskite exhibit a stark contrast. While CsCaCl3 is known to exist in a cubic perovskite structure and does not show any epitaxial strain induced phase transitions within an experimentally accessible range of compressive strains, RbZnCl3 is thermodynamically unstable in the perovskite phase and exhibits ultra-sensitive response at small epitaxial strains if constrained in the perovskite phase. We show that combining the two compositions in a double perovskite structure not only improves overall stability but also the strain-polarization coupling of the material. Our calculations predict a ground state with P4/nmm space group for the double perovskite, where A-site cations (i.e., Cs and Rb) are layer-ordered and B-site cations (i.e., Ca and Zn) prefer a rocksalt type ordering. The electronic structure and bandgap in this system are shown to be quite sensitive to the B-site cation ordering and is minimally affected by the ordering of A-site cations. We find that at experimentally accessible compressive strains CsRbCaZnCl6 can be phase transformed from its paraelectric ground state to an antiferroelectric state, where Zn atoms contribute predominantly to the polarization. Furthermore, both energy difference and activation barrier for a transformation between this antiferroelectric state and the corresponding ferroelectric configuration are predicted to be small. As a result, the computational approach presented here opens a new pathway towards a rational design of novel double perovskites with improved strain response and functionalities.

  14. Cation ordering and effect of biaxial strain in double perovskite CsRbCaZnCl{sub 6}

    SciTech Connect

    Pilania, G. Uberuaga, B. P.

    2015-03-21

    Here, we investigate the electronic structure, energetics of cation ordering, and effect of biaxial strain on double perovskite CsRbCaZnCl{sub 6} using first-principles calculations based on density functional theory. The two constituents (i.e., CsCaCl{sub 3} and RbZnCl{sub 3}) forming the double perovskite exhibit a stark contrast. While CsCaCl{sub 3} is known to exist in a cubic perovskite structure and does not show any epitaxial strain induced phase transitions within an experimentally accessible range of compressive strains, RbZnCl{sub 3} is thermodynamically unstable in the perovskite phase and exhibits ultra-sensitive response at small epitaxial strains if constrained in the perovskite phase. We show that combining the two compositions in a double perovskite structure not only improves overall stability but also the strain-polarization coupling of the material. Our calculations predict a ground state with P4/nmm space group for the double perovskite, where A-site cations (i.e., Cs and Rb) are layer-ordered and B-site cations (i.e., Ca and Zn) prefer a rocksalt type ordering. The electronic structure and bandgap in this system are shown to be quite sensitive to the B-site cation ordering and is minimally affected by the ordering of A-site cations. We find that at experimentally accessible compressive strains CsRbCaZnCl{sub 6} can be phase transformed from its paraelectric ground state to an antiferroelectric state, where Zn atoms contribute predominantly to the polarization. Furthermore, both energy difference and activation barrier for a transformation between this antiferroelectric state and the corresponding ferroelectric configuration are predicted to be small. The computational approach presented here opens a new pathway towards a rational design of novel double perovskites with improved strain response and functionalities.

  15. Technical communication: the effect of the double mask on anesthetic waste gas levels during pediatric mask inductions in dental offices.

    PubMed

    Kurrek, Matt M; Dain, Steven L; Kiss, Alexander

    2013-07-01

    A significant portion of office-based general anesthesia for pediatric patients is performed in dental offices and involves mask inductions with inhaled drugs. This can lead to significant pollution with waste gases. We assessed occupational exposure to anesthetic drugs during pediatric general anesthesia in dental offices and assessed the effectiveness of the "double mask." Nine freestanding dental offices had measurements of anesthetic waste gas levels taken before and immediately after implementation of a double-mask system. Levels of nitrous oxide decreased from a median of 40.0 parts per million (ppm; interquartile range [IQR] = 23.0-46.0 ppm, n = 9) to 3.0 ppm, (IQR = 2.3-4.7 ppm, n = 9, P = 0.0055) and exceeded 25 ppm in 0% of the 9 offices (upper 95% confidence limit 34%) when using the double mask. Levels of sevoflurane decreased from a median of 4.60 ppm (IQR = 3.10-7.00 ppm, n = 9) to 0 ppm (IQR = 0-0.39 ppm, n = 9, P = 0.0024) and exceeded 2 ppm in 0% of the 9 offices (upper 95% confidence limit 34%) when using the double mask. We demonstrated in our study that the double-mask system, when used with dental "high-volumes" suctions (high-volume evacuators producing approximately 12 m(3)/h) in freestanding dental offices, was sufficient to decrease the exposure to anesthetic waste gas during pediatric mask induction in at least two thirds of offices when compared with the traditional mask.

  16. Mucolytic Effectiveness of Tyloxapol in Chronic Obstructive Pulmonary Disease - A Double-Blind, Randomized Controlled Trial

    PubMed Central

    Koppitz, Martin; Eschenburg, Charlotte; Salzmann, Emilia; Rosewich, Martin; Schubert, Ralf; Zielen, Stefan

    2016-01-01

    Objective Mucoactive drugs should increase the ability to expectorate sputum and, ideally, have anti-inflammatory properties. The aim of the study was to evaluate the mucolytic activity of Tyloxapol compared to saline (0.9%) in COPD. Design A randomized, placebo-controlled, double-blinded crossover, clinical trial was carried out. Patients were randomly assigned to either inhale 5 ml Tyloxapol 1% or saline 0.9% solution three times daily for 3 weeks and vice versa for another 3 weeks. 28 patients (18 male, 10 female, 47 to 73 years old, median age 63.50) were screened, 21 were treated and 19 patients completed the study per protocol. Results A comparison of the two treatment phases showed that the primary endpoint sputum weight was statistically significant higher when patients inhaled Tyloxapol (mean 4.03 g, 95% CI: 2.34–5.73 g at week 3) compared to saline (mean 2.63 g, 95% CI: 1.73–3.53 g at week 3). The p-value at three weeks of treatment was 0.041 between treatment arms. Sputum cells decreased during the Tyloxapol treatment after 3 weeks, indicating that Tyloxapol might have some anti-neutrophilic properties. Lung function parameters (FVC, FEV1, RV, and RV/TLC) remained stable during the study, and no treatment effect was shown. Interestingly, there was a mean increase in all inflammatory cytokines (IL-1β, IL-6, and IL-8) during the saline treatment from day 1 to week 3, whereas during the Tyloxapol treatment, all cytokines decreased. Due to the small sample size and the large individual variation in sputum cytokines, these differences were not significant. However, analyses confirmed that Tyloxapol has significant anti-inflammatory properties in vitro. Despite the high number of inhalations (more than 1000), only 27 adverse events (20 during the Tyloxapol and seven during saline) were recorded. Eleven patients experienced AEs under Tyloxapol and six under saline treatment, which indicates that inhalation of saline or Tyloxapol is a very safe procedure

  17. Hot-wire chemical vapour deposition at low substrate temperatures for optoelectronic applications

    NASA Astrophysics Data System (ADS)

    Bakker, R.

    2010-09-01

    The need for large quantities of rapidly and cheaply produced electronic devices has increased rapidly over the past decades. The transistors and diodes that are used to build these devices are predominantly made of crystalline silicon. Since crystalline silicon is very expensive to produce on a large scale and cannot be directly deposited on plastic substrates, much research is being done on thin film amorphous or nanocrystalline semiconductors and insulators. Hot-wire chemical vapour deposition (HWCVD) is a novel, low cost, and convenient way to deposit these materials. The process can be controlled in such a way that specific chemical reactions take place and unwanted side reactions are minimized. It can easily be scaled up to produce large-area thin film electronics. Conventionally, plasma enhanced chemical vapour deposition (PECVD) is used to deposit semiconductors and inorganic dielectrics. Recently, HWCVD has been explored for fast deposition of such materials. An adaptation of HWCVD, initiated chemical vapour deposition (iCVD), offers the unique possibility of producing organic materials and polymers in a vacuum reactor, without the use of solvents. This technique was originally proposed at the Massachusetts institute of technology (MIT) by Prof. Karen Gleason. The iCVD process involves the creation of radicals by dissociation of a peroxide (a molecule with a ~O-O~ bond) by a heated wire in a vacuum reactor. This radical initiates a polymerization reaction of a vinyl (a molecule with a double carbon-carbon bond, ~C=C~) monomer at a substrate held at room temperature. This thesis describes a dedicated iCVD reactor for polymer deposition, installed at Utrecht University, along with a reactor with a cooled substrate holder in an existing HWCVD multi-chamber setup for low-temperature silicon nitride (SiNx) depositions. The most important features of these reactors are described and the characterization techniques are explained. This thesis contains four new

  18. Measuring fast variations of δ^{18}O and δ^2H in atmospheric water vapour using laser spectroscopy: an instrument inter-comparison and characterisation study

    NASA Astrophysics Data System (ADS)

    Aemisegger, F.; Sturm, P.; Graf, P.; Sodemann, H.; Pfahl, S.; Knohl, A.; Wernli, H.

    2012-04-01

    Fast variations of stable water isotopes in water vapour have become measurable lately using novel laser spectroscopic techniques. This allows us to perform process-based investigations of the atmospheric water cycle at the time scales of significant weather events. An important prerequisite for such studies implying automatic field measurements lasting for several weeks or even months is a detailed knowledge about sources of uncertainty and instrument properties. We present a comprehensive characterisation and comparison study of two commercial laser spectroscopic systems based on cavity ring-down spectroscopy (Picarro) and off-axis integrated cavity output spectroscopy (Los Gatos Resarch). The old versions (L1115-i, WVIA) and the new versions (L2130-i, WVIA-EP) of both systems were tested. The uncertainty components of the measurements were assessed in laboratory experiments, focussing on effects of (i) water vapour mixing ratio, (ii) measurement stability, (iii) uncertainties due to calibration and (iv) response times of the isotope measurements due to adsorption-desorption processes on the tubing and measurement cavity walls. Knowledge from our laboratory experiments was used to setup a one-week field campaign for comparing measurements of the ambient isotope signals from the L1115-i and WVIA systems. The optimal calibration strategy determined for both instruments was applied as well as the correction functions for water vapour mixing ratio effects. Using this field measurement data we address the question of how well the deuterium excess (d=δ2H-8δ18O) of atmospheric water vapour can be determined with laser spectroscopy. The deuterium excess is an interesting parameter for process-based atmospheric water cycle studies, which depends on humidity and temperature conditions at source location of water vapour. Up to now only very few high-time-resolution measurements of deuterium excess exist. Our concurrent measurements of atmospheric isotopes in water vapour

  19. Water vapour permeability of poly(lactic acid): Crystallinity and the tortuous path model

    NASA Astrophysics Data System (ADS)

    Duan, Z.; Thomas, N. L.

    2014-02-01

    The water vapour transmission rates (WVTR) through samples of polylactic acid of different crystallinities have been measured. Three different grades of commercial poly(lactic acid) (PLA) were used with different ratios of L-lactide and D-lactide to give a range of crystallinities from 0% to 50%. Sheets of PLA were prepared by melt compounding followed by compression moulding and annealing at different temperatures and for different times to give the range of crystallinities required. Crystallinity was measured by differential scanning calorimetry and the morphology of the samples was observed under crossed polars in a transmitted light microscope. Water vapour transmission rates through the films were measured at 38 °C and at a relative humidity of 90%. It was found that the measured values of WVTR decreased linearly with increasing crystallinity of the PLA from 0% to 50%. The results are discussed in terms of the effect of crystallinity on solubility and shown to fit the "Tortuous Path Model." The model was also successfully used to explain published data on water permeability of polyethylene terephthalate.

  20. Model studies of volatile diesel exhaust particle formation: organic vapours involved in nucleation and growth?

    NASA Astrophysics Data System (ADS)

    Pirjola, L.; Karl, M.; Rönkkö, T.; Arnold, F.

    2015-02-01

    High concentration of volatile nucleation mode particles (NUP) formed in the atmosphere during exhaust cools and dilutes have hazardous health effects and impair visibility in urban areas. Nucleation mechanisms in diesel exhaust are only poorly understood. We performed model studies using two sectional aerosol dynamics process models AEROFOR and MAFOR on the formation of particles in the exhaust of a diesel engine, equipped with an oxidative after-treatment system and running with low fuel sulphur content (FSC), under laboratory sampling conditions where the dilution system mimics real-world conditions. Different nucleation mechanisms were tested; based on the measured gaseous sulphuric acid (GSA) and non-volatile core and soot particle number concentrations of the raw exhaust, the model simulations showed that the best agreement between model predictions and measurements in terms of particle number size distribution was obtained by barrierless heteromolecular homogeneous nucleation between GSA and semi-volatile organic vapour (for example adipic acid) combined with the homogeneous nucleation of GSA alone. Major growth of the particles was predicted to occur by the same organic vapour at concentrations of (1-2) ×1012cm-3. The pre-existing core and soot mode concentrations had opposite trend on the NUP formation, and maximum NUP formation was predicted if a diesel particle filter (DPF) was used. On the other hand, NUP formation was ceased if the GSA concentration was less than 1010cm-3 which suggests, based on the measurements, the usage of biofuel to prevent volatile particles in diesel exhaust.

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

    SciTech Connect

    Richter, Wolfgang

    2007-06-14

    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.

  2. Synthesis of Tin Nitride SnxNyNanowires by Chemical Vapour Deposition

    PubMed Central

    2009-01-01

    Tin nitride (SnxNy) nanowires have been grown for the first time by chemical vapour deposition on n-type Si(111) and in particular by nitridation of Sn containing NH4Cl at 450 °C under a steady flow of NH3. The SnxNynanowires have an average diameter of 200 nm and lengths ≥5 μm and were grown on Si(111) coated with a few nm’s of Au. Nitridation of Sn alone, under a flow of NH3is not effective and leads to the deposition of Sn droplets on the Au/Si(111) surface which impedes one-dimensional growth over a wide temperature range i.e. 300–800 °C. This was overcome by the addition of ammonium chloride (NH4Cl) which undergoes sublimation at 338 °C thereby releasing NH3and HCl which act as dispersants thereby enhancing the vapour pressure of Sn and the one-dimensional growth of SnxNynanowires. In addition to the action of dispersion, Sn reacts with HCl giving SnCl2which in turn reacts with NH3leading to the formation of SnxNyNWs. A first estimate of the band-gap of the SnxNynanowires grown on Si(111) was obtained from optical reflection measurements and found to be ≈2.6 eV. Finally, intricate assemblies of nanowires were also obtained at lower growth temperatures. PMID:20596341

  3. Polymer nanocomposite nanomechanical cantilever sensors: material characterization, device development and application in explosive vapour detection.

    PubMed

    Seena, V; Fernandes, Avil; Pant, Prita; Mukherji, Soumyo; Rao, V Ramgopal

    2011-07-22

    This paper reports an optimized and highly sensitive piezoresistive SU-8 nanocomposite microcantilever sensor and its application for detection of explosives in vapour phase. The optimization has been in improving its electrical, mechanical and transduction characteristics. We have achieved a better dispersion of carbon black (CB) in the SU-8/CB nanocomposite piezoresistor and arrived at an optimal range of 8-9 vol% CB concentration by performing a systematic mechanical and electrical characterization of polymer nanocomposites. Mechanical characterization of SU-8/CB nanocomposite thin films was performed using the nanoindentation technique with an appropriate substrate effect analysis. Piezoresistive microcantilevers having an optimum carbon black concentration were fabricated using a design aimed at surface stress measurements with reduced fabrication process complexity. The optimal range of 8-9 vol% CB concentration has resulted in an improved sensitivity, low device variability and low noise level. The resonant frequency and spring constant of the microcantilever were found to be 22 kHz and 0.4 N m(-1) respectively. The devices exhibited a surface stress sensitivity of 7.6 ppm (mN m(-1))(-1) and the noise characterization results support their suitability for biochemical sensing applications. This paper also reports the ability of the sensor in detecting TNT vapour concentration down to less than six parts per billion with a sensitivity of 1 mV/ppb. PMID:21673380

  4. 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.

  5. Rain scavenging of tritiated water vapour: a numerical Eulerian stationary model.

    PubMed

    Atanassov, D; Galeriu, D

    2011-01-01

    The tradition in tritium washout modeling is to unite the washout model with a Gaussian plume model describing dispersion of tritium vapour in the atmosphere. In the present study, an alternative approach is proposed. A numerical Eulerian model that describes washout independently of dispersion is developed. The sensitivity analysis to model parameters has shown that the washout process is influenced most significantly by rainfall parameters and air temperature: different raindrop size distributions cause differences of up to about 70% in the washout outputs; a change of 15°C in the air temperature causes an effect of about 50%. Results are presented showing calculated values of washout outputs (tritium concentration in rain, tritium downward flux, washout coefficient) for different tritium vapour profiles, rainfall rates and air temperatures. The general conclusion is that the washout process is too complex to be described comprehensively by the simple washout coefficient concept. We suggest the approach proposed here for directly calculating the tritium downward flux and concentration in the rainwater is preferable.

  6. The Effect of Three Methods of Supporting the Double Bass on Muscle Tension.

    ERIC Educational Resources Information Center

    Dennis, Allan

    1984-01-01

    Using different methods of holding the double bass, college students performed Beethoven's Symphony No. 9. Audio recordings of performance were rated. Muscle tension readings from the left arm, right arm, upper back, and lower back were taken, using electromyography. Results suggest nonsignificant differences in both performance quality and muscle…

  7. Double-Shift Schooling: Design and Operation for Cost-Effectiveness.

    ERIC Educational Resources Information Center

    Bray, Mark

    In a double-shift system, which aims primarily to extend access and minimize unit costs, schools cater to two entirely separate groups of pupils during a school day. The first group of pupils usually attends school from early morning until mid-day, and the second group usually attends from mid-day to late afternoon. Each group uses the same…

  8. Effectiveness of medical treatment in overcoming the ureteral double-J stent related symptoms

    PubMed Central

    Kuyumcuoglu, Ugur; Eryildirim, Bilal; Tuncer, Murat; Faydaci, Gokhan; Tarhan, Fatih; Ozgül, Aydin

    2012-01-01

    Background: We investigated whether the frequency of lower urinary tract symptoms (LUTS) increased in patients in whom double-J stents were applied. We also evaluated several medical therapy protocols to treat symptoms related with ureteral stents. Materials and Methods: A total of 108 patients, in whom unilateral double-j stent was applied during ureteral stone treatment, were included. Before the double-J stent was applied, all patients completed storage components of the “International Prostate Symptom Score” (IPSSs), quality of life components of the IPSS (IPSS-QOL) and “Overactive Bladder Questionnaire” (OABq) forms and scores were calculated. After the procedure, cases were randomized into 5 groups, an antiinflammatory was given to Group 1, spasmolytic to Group 2, anticholinergic to Group 3 and α-blocker to Group 4. No additional drug was given to Group 5 as this control group. During the fourth week of the procedure, IPSSs, IPSS-QOL and OABq forms were again completed and scores were compared with the previous ones. Results: When all the cases were evaluated, the IPSSs, IPSS-QOL and OABq scores of patients in whom the double-J stent was applied were statistically significantly higher the procedure. Compared to the control group, the cases where the double-J stent was applied showed a higher IPSSs, IPSS-QOL and OABq scores and none of the medical therapies could prevent this increase. Interpretation: The frequency of LUTS increased in cases where the ureteral stent was applied and discomfort continued as long as the stent stayed in the body. PMID:21914427

  9. ELECTRON DONOR ACCEPTOR DESCRIPTORS OF THE SINGLE AND DOUBLE BONDED SUBSTITUENT AND HETEROATOM INCORPORATION EFFECTS. A REVIEW.

    PubMed

    Mazurek, Andrzej

    2016-01-01

    The properties of the series of Electron Donor-Acceptor (EDA) descriptors of classical substituent effect (sEDA(I), pEDA(I)), double bonded substituent effect (sEDA(=), pEDA(=)), heteroatom incorporation effect in monocyclic systems (sEDA(II), pEDA(II)), and in ring-junction position (sEDA(III), pEDA(III)), are reviewed. The descriptors show the amount of electrons donated to or withdrawn from the σ-(sEDA) or π(pEDA) valence orbitals by the substituent or incorporant. The new descriptors are expected to enrich the potency of QSAR analyses in drug design and materials chemistry.

  10. Lormetazepam - a benzodiazepine derivative without hangover effect? A double-blind study with chronic insomniacs in a general practice setting.

    PubMed

    Heidrich, H; Ott, H; Beach, R C

    1981-01-01

    Lormetazepam, a new short-acting benzodiazepine, was tested multicentrally in 15 general practices. The subjects were 62 chronically sleep-disturbed patients. The first 7 days served as a placebo baseline week, the next 14 days were either lormetazepam or placebo in a randomized double-blind design, and during the last week placebo was given again to measure rebound effects. Lormetazepam was found to be an effective hypnotic that causes virtually no hangover the next morning. In this study no rebound effects could be measured. Visual analogue scales, among others, were used for the assessment of sleep characteristics.

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

    PubMed

    Park, Soo J; Morelli, Renata; 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

  12. 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

  13. Combined effects of deforestation and doubled atmospheric CO{sub 2} concentrations on the climate of Amazonia

    SciTech Connect

    Costa, M.H.; Foley, J.A.

    2000-01-01

    It is generally expected that the Amazon basin will experience at least two major environmental changes during the next few decades and centuries: (1) increasing areas of forest will be converted to pasture and cropland, and (2) concentrations of atmospheric CO{sub 2} will continue to rise. In this study, the authors use the National Center for Atmospheric Research GENESIS atmospheric general circulation model, coupled to the Integrated Biosphere Simulator, to determine the combined effects of large-scale deforestation and increased CO{sub 2} concentrations (including both physiological and radiative effects) on Amazonian climate. In these simulations, deforestation decreases basin-average precipitation by 0.73 mm day{sup {minus}1} over the basin, as a consequence of the general reduction in vertical motion above the deforested area (although there are some small regions with increased vertical motion). The overall effect of doubled CO{sub 2} concentrations in Amazonia is an increase in basin-average precipitation of 0.28 mm day{sup {minus}1}. The combined effect of deforestation and doubled CO{sub 2}, including the interactions among the processes, is a decrease in the basin-average precipitation of 0.42 mm day{sup {minus}1}. While the effects of deforestation and increasing CO{sub 2} concentrations on precipitation tend to counteract one another, both processes work to warm the Amazon basin. The effect of deforestation and increasing CO{sub 2} concentrations both tent to increase surface temperature, mainly because of decreases in evapotranspiration and the radiative effect of CO{sub 2}. The combined effect of deforestation and doubled CO{sub 2}, including the interactions among the processes, increases the basin-average temperature by roughly 3.5 C.

  14. Effect of Double Aging Heat Treatment on the Short-Term Creep Behavior of the Inconel 718

    NASA Astrophysics Data System (ADS)

    Caliari, Felipe Rocha; Candioto, Kátia Cristiane Gandolpho; Couto, Antônio Augusto; Nunes, Carlos Ângelo; Reis, Danieli Aparecida Pereira

    2016-06-01

    This research studies the effect of double aging heat treatment on the short-term creep behavior of the superalloy Inconel 718. The superalloy, received in the solution treated state, was subjected to an aging treatment which comprises a solid solution at 1095 °C for 1 h, a first aging step of 955 °C for 1 h, then aged at 720 and 620 °C, 8 h each step. Creep tests at constant load mode, under temperatures of 650, 675, 700 °C and stress of 510, 625 and 700 MPa, were performed before and after heat treatment. The results indicate that after the double aging heat treatment creep resistance is increased, influenced by the presence of precipitates γ' and γ″ and its interaction with the dislocations, by grain size growth (from 8.20 to 7.23 ASTM) and the increase of hardness by approximately 98%. Creep parameters of primary and secondary stages have been determined. There is a breakdown relationship between dot{\\upvarepsilon }_{{s}} and stress at 650 °C of Inconel 718 as received, around 600 MPa. By considering the internal stress values, effective stress exponent, effective activation energy, and TEM images of Inconel 718 double aged, it is suggested that the creep mechanism is controlled by the interaction of dislocations with precipitates. The fracture mechanism of Inconel 718 as received is transgranular (coalescence of dimples) and mixed (transgranular-intergranular), whereas the Inconel 718 double aged condition crept surfaces evidenced the intergranular fracture mechanism.

  15. Experimental study of multipass copper vapour laser amplifiers

    SciTech Connect

    Karpukhin, Vyacheslav T; Malikov, Mikhail M

    2008-12-31

    Repetitively pulsed multipass copper vapour amplifiers are studied experimentally. A considerable increase in the peak power of laser pulses was achieved by using a special scheme of the amplifier. It is found that the main reasons preventing an increase in the peak power during many passages of the beam are the competitive development of lasing from spontaneous seeds in a parasitic resonator formed by the fold mirrors of a multipass amplifier, a decrease in the amplification during the last passages, and an increase in the pulse width at the amplifier output. (lasers. amplifiers)

  16. A diamond-windowed IR-cell for inorganic vapours

    NASA Astrophysics Data System (ADS)

    Rytter, E.; Hvistendahl, J.; Tomita, T.

    An evacuable cell system which can be used for recording infrared spectra of corrosive vapours has been developed. The cell body is made of gold-plated nickel, and sealing of the diamond windows is performed with gold O-rings. The excellent transmittance of type IIa diamond makes it possible to scan the far infrared region below 1500 cm -1. Furthermore, isothermal conditions can be maintained up to approximately 600°C before the windows turn opaque. Use of minor exchangeable parts gives the opportunity of both transmission and emission spectroscopy.

  17. 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

  18. Combined Dial Sounding of Ozone, Water Vapour and Aerosol

    NASA Astrophysics Data System (ADS)

    Trickl, Thomas; Vogelmann, Hannes

    2016-06-01

    Routine high-quality lidar measurements of ozone, water vapour and aerosol at Garmisch-Partenkirchen since 2007 have made possible more comprehensive atmospheric studies and lead to a growing insight concerning the most frequently occurring long-range transport pathways. In this contribution we present as examples results on stratospheric layers travelling in the free troposphere for extended periods of time without eroding. In particular, we present a case of an intrusion layer that subsided over as many as fifteen days and survived the interference by strong Canadian fires. These results impose a challenge on atmospheric modelling that grossly overestimates free-tropospheric mixing.

  19. Immunomodulatory Effects of ResistAid™: A Randomized, Double-Blind, Placebo-Controlled, Multidose Study

    PubMed Central

    Udani, Jay K.

    2013-01-01

    Objective To evaluate the ability of a proprietary arabinogalactan extract from the larch tree (ResistAid, Lonza Ltd., Basel, Switzerland) to change the immune response in healthy adults to a standardized antigenic challenge (tetanus and influenza vaccines) in a dose-dependent manner compared to placebo. Methods This randomized, double-blind, placebo-controlled trial included 75 healthy adults (18–61 years old). Subjects were randomized to receive either 1.5 or 4.5 g/day of ResistAid or placebo for 60 days. At day 30, subjects were administered both tetanus and influenza vaccines. Serum antigenic response (tetanus immunoglobulin G [IgG], influenza A and B IgG and immunoglobulin M [IgM]) was measured at days 45 (15 days after vaccination) and 60 (30 days after vaccination) of the study and compared to baseline antibody levels. Frequency and intensity of adverse events were monitored throughout the study. Results As expected, all 3 groups demonstrated an expected rise in tetanus IgG levels 15 and 30 days following the vaccine. There was a strongly significant difference in the rise in IgG levels at day 60 in the 1.5 g/day group compared to placebo (p = 0.008). In the 4.5 g/day group, there was significant rise in tetanus IgG at days 45 and 60 compared to baseline (p < 0.01) but these values were not significant compared to placebo. Neither group demonstrated any significant elevations in IgM or IgG antibodies compared to placebo following the influenza vaccine. There were no clinically or statistically significant or serious adverse events. Conclusions ResistAid at a dose of 1.5 g/day significantly increased the IgG antibody response to tetanus vaccine compared to placebo. In conjunction with earlier studies, this validates the effect of ResistAid on the augmentation of the response to bacterial antigens (in the form of vaccine). PMID:24219376

  20. Theoretical Study of the Effect of an AlGaAs Double Heterostructure on Metal-Semiconductor-Metal Photodetector Performance

    NASA Technical Reports Server (NTRS)

    Salem, Ali F.; Smith, Arlynn W.; Brennan, Kevin F.

    1994-01-01

    The impulse and square-wave input response of different GaAs metal-semiconductor-metal photodetector (MSM) designs are theoretically examined using a two dimensional drift- diffusion numerical calculation with a thermionic-field emission boundary condition model for the heterojunctions. The rise time and the fall time of the output signal current are calculated for a simple GaAs, epitaxially grown, MSM device as well as for various double-heterostructure barrier devices. The double heterostructure devices consist of an AlGaAs layer sandwiched between the top GaAs active, absorption layer and the bottom GaAs substrate. The effect of the depth of the AlGaAs layer on the speed and responsivity of the MSM devices is examined. It is found that there is an optimal depth, at fixed applied bias, of the AlGaAs layer within the structure that provides maximum responsivity at minimal compromise in speed.

  1. Effects of Double Transgenesis of Somatotrophic Axis (GH/GHR) on Skeletal Muscle Growth of Zebrafish (Danio rerio).

    PubMed

    Silva, Ana Cecilia Gomes; Almeida, Daniela Volcan; Nornberg, Bruna Felix; Figueiredo, Marcio Azevedo; Romano, Luis Alberto; Marins, Luis Fernando

    2015-12-01

    Transgenic fish for growth hormone (GH) has been considered as a potential technological improvement in aquaculture. In this study, a double-transgenic zebrafish was used to evaluate the effect of GH and its receptor (GHR) on muscle growth. Double transgenics reached the same length of GH transgenic, but with significantly less weight, featuring an unbalanced growth. The condition factor of GH/GHR-transgenic fish was lower than the other genotypes. Histological analysis showed a decrease in the percentage of thick muscle fibers in GH/GHR genotype of ∼ 80% in comparison to GH-transgenic line. The analysis of gene expression showed a significant decrease in genes related to muscle growth in GH/GHR genotype. It seems that concomitant overexpression of GH and GHR resulted in a strong decrease of the somatotrophic axis intracellular signaling by diminishing its principal transcription factor signal transducer and activator of transcription 5.1 (STAT5.1). PMID:26574627

  2. Effects of Double Transgenesis of Somatotrophic Axis (GH/GHR) on Skeletal Muscle Growth of Zebrafish (Danio rerio).

    PubMed

    Silva, Ana Cecilia Gomes; Almeida, Daniela Volcan; Nornberg, Bruna Felix; Figueiredo, Marcio Azevedo; Romano, Luis Alberto; Marins, Luis Fernando

    2015-12-01

    Transgenic fish for growth hormone (GH) has been considered as a potential technological improvement in aquaculture. In this study, a double-transgenic zebrafish was used to evaluate the effect of GH and its receptor (GHR) on muscle growth. Double transgenics reached the same length of GH transgenic, but with significantly less weight, featuring an unbalanced growth. The condition factor of GH/GHR-transgenic fish was lower than the other genotypes. Histological analysis showed a decrease in the percentage of thick muscle fibers in GH/GHR genotype of ∼ 80% in comparison to GH-transgenic line. The analysis of gene expression showed a significant decrease in genes related to muscle growth in GH/GHR genotype. It seems that concomitant overexpression of GH and GHR resulted in a strong decrease of the somatotrophic axis intracellular signaling by diminishing its principal transcription factor signal transducer and activator of transcription 5.1 (STAT5.1).

  3. A possible means of monitoring the progress of demyelination in multiple sclerosis: effect of body temperature on visual perception of double light flashes.

    PubMed

    Galvin, R J; Regan, D; Heron, J R

    1976-09-01

    The ability to discriminate closely separated pairs of light flashes as being double is impaired in multiple sclerosis. The effects of altering body temperature on double flash resolution and on visual acuity were studied in four multiple sclerosis patients and in control subjects. At demyelinated sites heating impaired and cooling improved double flash resolution. Visual acuity behaved similarly. The double flash test was very sensitive, changing up to 75 ms in response to simple heating and cooling procedures that produced small variations in acuity. Apart from its diagnostic value, the double flash test furnishes a simple in vivo model to study the effect of temperature change (and potential symptomatic therapy) on conduction in partially demyelinated axons in the visual system.

  4. Effects of heavy ions on inactivation and DNA double strand breaks in Deinococcus radiodurans R1.

    PubMed

    Zimmermann, H; Schafer, M; Schmitz, C; Bucker, H

    1994-10-01

    Inactivation and double strand break (dsb) induction after heavy ion irradiation were studied in stationary phase cells of the highly radiation resistant bacterium Deinococcus radiodurans R1. There is evidence that the radiation sensitivity of this bacterium is nearly independent on energy in the range of up to 15 MeV/u for lighter ions (Ar). The responses to dsb induction for charged particles show direct relationship between increasing radiation dose and residual intact DNA.

  5. Effects of heavy ions on inactivation and DNA double strand breaks in Deinococcus radiodurans R1

    NASA Astrophysics Data System (ADS)

    Zimmermann, H.; Schäfer, M.; Schmitz, C.; Bücker, H.

    1994-10-01

    Inactivation and double strand break (dsb) induction after heavy ion irradiation were studied in stationary phase cells of the highly radiation resistant bacterium Deinococcus radiodurans R1. There is evidence that the radiation sensitivity of this bacterium is nearly independent on energy in the range of up to 15 MeV/u for lighter ions (Ar). The responses to dsb induction for charged particles show direct relationship between increasing radiation dose and residual intact DNA.

  6. Effects of heavy ions on inactivation and DNA double strand breaks in Deinococcus radiodurans R1.

    PubMed

    Zimmermann, H; Schafer, M; Schmitz, C; Bucker, H

    1994-10-01

    Inactivation and double strand break (dsb) induction after heavy ion irradiation were studied in stationary phase cells of the highly radiation resistant bacterium Deinococcus radiodurans R1. There is evidence that the radiation sensitivity of this bacterium is nearly independent on energy in the range of up to 15 MeV/u for lighter ions (Ar). The responses to dsb induction for charged particles show direct relationship between increasing radiation dose and residual intact DNA. PMID:11539954

  7. The impact of microwave absorber and radome geometries on GNSS measurements of station coordinates and atmospheric water vapour

    NASA Astrophysics Data System (ADS)

    Ning, T.; Elgered, G.; Johansson, J. M.

    2011-01-01

    We have used microwave absorbing material in different geometries around ground-based Global Navigation Satellite System (GNSS) antennas in order to mitigate multipath effects on the estimates of station coordinates and atmospheric water vapour. The influence of a hemispheric radome - of the same type as in the Swedish GPS network SWEPOS - was also investigated. Two GNSS stations at the Onsala Space Observatory were used forming a 12 m baseline. GPS data from October 2008 to November 2009 were analyzed by the GIPSY/OASIS II software using the Precise Point Positioning (PPP) processing strategy for five different elevation cutoff angles from 5° to 25°. We found that the use of the absorbing material decreases the offset in the estimated vertical component of the baseline from ˜27 mm to ˜4 mm when the elevation cutoff angle varies from 5° to 20°. The horizontal components are much less affected. The corresponding offset in the estimates of the atmospheric Integrated Water Vapour (IWV) decreases from ˜1.6 kg/m2 to ˜0.3 kg/m2. Changes less than 5 mm in the offsets in the vertical component of the baseline are seen for all five elevation cutoff angle solutions when the antenna was covered by a hemispheric radome. Using the radome affects the IWV estimates less than 0.4 kg/m2 for all different solutions. IWV comparisons between a Water Vapour Radiometer (WVR) and the GPS data give consistent results.

  8. Tackling contamination of the hospital environment by methicillin-resistant Staphylococcus aureus (MRSA): a comparison between conventional terminal cleaning and hydrogen peroxide vapour decontamination.

    PubMed

    French, G L; Otter, J A; Shannon, K P; Adams, N M T; Watling, D; Parks, M J

    2004-05-01

    The hospital environment can sometimes harbour methicillin-resistant Staphylococcus aureus (MRSA) but is not generally regarded as a major source of MRSA infection. We conducted a prospective study in surgical wards of a London teaching hospital affected by MRSA, and compared the effectiveness of standard cleaning with a new method of hydrogen peroxide vapour decontamination. MRSA contamination, measured by surface swabbing was compared before and after terminal cleaning that complied with UK national standards, or hydrogen peroxide vapour decontamination. All isolation rooms, ward bays and bathrooms tested were contaminated with MRSA and several antibiogram types were identified. MRSA was common in sites that might transfer organisms to the hands of staff and was isolated from areas and bed frames used by non-MRSA patients. Seventy-four percent of 359 swabs taken before cleaning yielded MRSA, 70% by direct plating. After cleaning, all areas remained contaminated, with 66% of 124 swabs yielding MRSA, 74% by direct plating. In contrast, after exposing six rooms to hydrogen peroxide vapour, only one of 85 (1.2%) swabs yielded MRSA, by enrichment culture only. The hospital environment can become extensively contaminated with MRSA that is not eliminated by standard cleaning methods. In contrast, hydrogen peroxide vapour decontamination is a highly effective method of eradicating MRSA from rooms, furniture and equipment. Further work is needed to determine the importance of environmental contamination with MRSA and the effect on hospital infection rates of effective decontamination.

  9. Effect of double-step steam explosion pretreatment in bioethanol production from softwood.

    PubMed

    Cotana, Franco; Cavalaglio, Gianluca; Gelosia, Mattia; Coccia, Valentina; Petrozzi, Alessandro; Nicolini, Andrea

    2014-09-01

    The study investigated the production of bioethanol from softwood, in particular pine wood chip. The steam explosion pretreatment was largely investigated, evaluating also the potential use of a double-step process to increase ethanol production through the use of both solid and liquid fraction after the pretreatment. The pretreatment tests were carried out at different conditions, determining the composition of solid and liquid fraction and steam explosion efficiency. The enzymatic hydrolysis was carried out with Ctec2 enzyme while the fermentation was carried out using Saccharomyces Cerevisiae yeast "red ethanol". It was found that the best experimental result was obtained for a single-step pretreated sample (10.6 g of ethanol/100 g of initial biomass dry basis) for a 4.53 severity. The best double-step overall performance was equal to 8.89 g ethanol/100 g of initial biomass dry basis for a 4.27 severity. The enzymatic hydrolysis strongly depended on the severity of the pretreatment while the fermentation efficiency was mainly influenced by the concentration of the inhibitors. The ethanol enhancing potential of a double-step steam explosion could slightly increase the ethanol production compared to single-step potential.

  10. Effect of cation ordering on oxygen vacancy diffusion pathways in double perovskites

    DOE PAGES

    Uberuaga, Blas Pedro; Pilania, Ghanshyam

    2015-07-08

    Perovskite structured oxides (ABO3) are attractive for a number of technological applications, including as superionics because of the high oxygen conductivities they exhibit. Double perovskites (AA’BB’O6) provide even more flexibility for tailoring properties. Using accelerated molecular dynamics, we examine the role of cation ordering on oxygen vacancy mobility in one model double perovskite SrLaTiAlO6. We find that the mobility of the vacancy is very sensitive to the cation ordering, with a migration energy that varies from 0.6 to 2.7 eV. In the extreme cases, the mobility is both higher and lower than either of the two end member single perovskites.more » Further, the nature of oxygen vacancy diffusion, whether one-dimensional, two-dimensional, or three-dimensional, also varies with cation ordering. We correlate the dependence of oxygen mobility on cation structure to the distribution of Ti4+ cations, which provide unfavorable environments for the positively charged oxygen vacancy. The results demonstrate the potential of using tailored double perovskite structures to precisely control the behavior of oxygen vacancies in these materials.« less

  11. Effect of cation ordering on oxygen vacancy diffusion pathways in double perovskites

    SciTech Connect

    Uberuaga, Blas Pedro; Pilania, Ghanshyam

    2015-07-08

    Perovskite structured oxides (ABO3) are attractive for a number of technological applications, including as superionics because of the high oxygen conductivities they exhibit. Double perovskites (AA’BB’O6) provide even more flexibility for tailoring properties. Using accelerated molecular dynamics, we examine the role of cation ordering on oxygen vacancy mobility in one model double perovskite SrLaTiAlO6. We find that the mobility of the vacancy is very sensitive to the cation ordering, with a migration energy that varies from 0.6 to 2.7 eV. In the extreme cases, the mobility is both higher and lower than either of the two end member single perovskites. Further, the nature of oxygen vacancy diffusion, whether one-dimensional, two-dimensional, or three-dimensional, also varies with cation ordering. We correlate the dependence of oxygen mobility on cation structure to the distribution of Ti4+ cations, which provide unfavorable environments for the positively charged oxygen vacancy. The results demonstrate the potential of using tailored double perovskite structures to precisely control the behavior of oxygen vacancies in these materials.

  12. Analytical and experimental investigation on transmission loss of clamped double panels: implication of boundary effects.

    PubMed

    Xin, F X; Lu, T J

    2009-03-01

    The air-borne sound insulation performance of a rectangular double-panel partition clamp mounted on an infinite acoustic rigid baffle is investigated both analytically and experimentally and compared with that of a simply supported one. With the clamped (or simply supported) boundary accounted for by using the method of modal function, a double series solution for the sound transmission loss (STL) of the structure is obtained by employing the weighted residual (Galerkin) method. Experimental measurements with Al double-panel partitions having air cavity are subsequently carried out to validate the theoretical model for both types of the boundary condition, and good overall agreement is achieved. A consistency check of the two different models (based separately on clamped modal function and simply supported modal function) is performed by extending the panel dimensions to infinite where no boundaries exist. The significant discrepancies between the two different boundary conditions are demonstrated in terms of the STL versus frequency plots as well as the panel deflection mode shapes. PMID:19275309

  13. Nano structured carbon nitrides prepared by chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Karuppannan, Ramesh; Prashantha, M.

    2010-08-01

    Nanostructured carbon nitride films were prepared by pyrolysis assisted chemical vapour deposition(CVD). A two zone furnace with a temperature profile having a uniform temperature over a length of 20 cm length has been designed and developed. The precursor Azabenzimidazole was taken in a quartz tube and evaporated at 400 0C. The dense vapours enter the pyrolysis zone kept at a desired temperature and deposit on the quartz substrates. The FTIR spectrum of the prepared samples shows peaks at 1272 cm-1 (C.N stretching) and 1600 cm-1 (C=N) confirms the bonding of nitrogen with carbon. Raman D and G peaks, are observed at 1360 cm-1 and 1576 cm-1 respectively. XPS core level spectra of C 1s and N 1s show the formation of π bonding between carbon and nitrogen atoms. The size of the nano crystals estimated from the SEM images and XRD is ~100 nm. In some regions of the sample a maximum of 57 atom % of nitrogen has been observed.

  14. Improved grand canonical sampling of vapour-liquid transitions

    NASA Astrophysics Data System (ADS)

    Wilding, Nigel B.

    2016-10-01

    Simulation within the grand canonical ensemble is the method of choice for accurate studies of first order vapour-liquid phase transitions in model fluids. Such simulations typically employ sampling that is biased with respect to the overall number density in order to overcome the free energy barrier associated with mixed phase states. However, at low temperature and for large system size, this approach suffers a drastic slowing down in sampling efficiency. The culprits are geometrically induced transitions (stemming from the periodic boundary conditions) which involve changes in droplet shape from sphere to cylinder and cylinder to slab. Since the overall number density does not discriminate sufficiently between these shapes, it fails as an order parameter for biasing through the transitions. Here we report two approaches to ameliorating these difficulties. The first introduces a droplet shape based order parameter that generates a transition path from vapour to slab states for which spherical and cylindrical droplets are suppressed. The second simply biases with respect to the number density in a tetragonal subvolume of the system. Compared to the standard approach, both methods offer improved sampling, allowing estimates of coexistence parameters and vapor-liquid surface tension for larger system sizes and lower temperatures.

  15. Detecting vapour bubbles in simulations of metastable water.

    PubMed

    González, Miguel A; Menzl, Georg; Aragones, Juan L; Geiger, Philipp; Caupin, Frederic; Abascal, Jose L F; Dellago, Christoph; Valeriani, Chantal

    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 distinguish 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. PMID:25399176

  16. Detecting vapour bubbles in simulations of metastable water

    SciTech Connect

    González, Miguel A.; Abascal, Jose L. F.; Valeriani, Chantal E-mail: cvaleriani@quim.ucm.es; Menzl, Georg; Geiger, Philipp; Dellago, Christoph E-mail: cvaleriani@quim.ucm.es; Aragones, Juan L.; Caupin, Frederic

    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 distinguish 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.

  17. Detecting vapour bubbles in simulations of metastable water.

    PubMed

    González, Miguel A; Menzl, Georg; Aragones, Juan L; Geiger, Philipp; Caupin, Frederic; Abascal, Jose L F; Dellago, Christoph; Valeriani, Chantal

    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 distinguish 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.

  18. Detecting vapour bubbles in simulations of metastable water

    NASA Astrophysics Data System (ADS)

    González, Miguel A.; Menzl, Georg; Aragones, Juan L.; Geiger, Philipp; Caupin, Frederic; Abascal, Jose L. F.; Dellago, Christoph; Valeriani, Chantal

    2014-11-01

    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 distinguish 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.

  19. Effect of double dose oseltamivir on clinical and virological outcomes in children and adults admitted to hospital with severe influenza: double blind randomised controlled trial

    PubMed Central

    2013-01-01

    Objective To investigate the validity of recommendations in treatment guidelines to use higher than approved doses of oseltamivir in patients with severe influenza. Design Double blind randomised trial. Setting Thirteen hospitals in Indonesia, Singapore, Thailand, and Vietnam. Participants Patients aged ≥1 year admitted to hospital with confirmed severe influenza. Interventions Oral oseltamivir at double dose (150 mg twice a day/paediatric equivalent) versus standard dose (75 mg twice a day/paediatric equivalent). Main outcome measure Viral status according to reverse transcriptase polymerase chain reaction (RT-PCR) for influenza RNA in nasal and throat swabs on day five. Results Of 326 patients (including 246 (75.5%) children aged <15), 165 and 161 were randomised to double or standard dose oseltamivir, respectively. Of these, 260 (79.8%) were infected with influenza virus A (133 (40.8%) with A/H3N2, 72 (22.1%) with A/H1N1-pdm09, 38 (11.7%) with seasonal A/H1N1, 17 (5.2%) with A/H5N1) and 53 (16.2%) with influenza virus B. A further 3.9% (13) were false positive by rapid antigen test (negative by RT-PCR and no rise in convalescent haemagglutination inhibition titers). Similar proportions of patients were negative for RT-PCR on day five of treatment: 115/159 (72.3%, 95% confidence interval 64.9% to 78.7%) double dose recipients versus 105/154 (68.2%, 60.5% to 75.0%) standard dose recipients; difference 4.2% (−5.9 to 14.2); P=0.42. No differences were found in clearance of virus in subgroup analyses by virus type/subtype, age, and duration of illness before randomisation. Mortality was similar: 12/165 (7.3%, 4.2% to 12.3%) in double dose recipients versus 9/161 (5.6%, 3.0% to 10.3%) in standard dose recipients. No differences were found between double and standard dose arms in median days on supplemental oxygen (3 (interquartile range 2-5) v 3.5 (2-7)), in intensive care (4.5 (3-6) v 5 (2-11), and on mechanical ventilation (2.5 (1-16) v 8 (1-16)), respectively

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

    PubMed

    Prosperetti, Andrea

    2015-10-01

    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.

  1. 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

  2. Vapour toxicity & repellence of some essential oils & terpenoids to adults of Aedes aegypti (L) (Diptera: Culicidae).

    PubMed

    Vartak, P H; Sharma, R N

    1993-05-01

    Bioefficacy of commercially used synthetic insecticides/repellents and potential of selected essential oils and terpenoids were assessed against mosquitoes. Essential oils and terpenoids, were vapourised in commercially manufactured mosquito repellent electronic assemblies and effects of such vapours were tested on 6-7 days old adult female Aedes aegypti. Commercially available 'mats' (coir rectangles) impregnated with allethrin were used as standards for comparison of Kt50 and Kt90 values. Fastest knock-down was seen in case of allethrin, followed by terpeneol (anhydrous) and (-) carvone. Maximum knock-down time was observed for beta citronellol. All compounds exhibited a repellent effect also, terpeneol (anhydrous) being the best, followed by (-) carvone and citronellal. In repellent tests, no mortality was caused by terpenoids, but allethrin caused > 80 per cent knock-down. PMID:8406635

  3. A quasi-physical model for predicting the thermal insulation and moisture vapour resistance of clothing.

    PubMed

    Qian, Xiaoming; Fan, Jintu

    2009-07-01

    Based on the improved understanding of the effects of wind and walking motion on the thermal insulation and moisture vapour resistance of clothing induced by air ventilation in the clothing system, a new model has been derived based on fundamental mechanisms of heat and mass transfer, which include conduction, diffusion, radiation and natural convection, wind penetration and air ventilation. The model predicts thermal insulation of clothing under body movement and windy conditions from the thermal insulation of clothing measured when the person is standing in the still air. The effects of clothing characteristics such as fabric air permeability, garment style, garment fitting and construction have been considered in the model through the key prediction parameters. With the new model, an improved prediction accuracy is achieved with a percentage of fit being as high as 0.96.

  4. The effect of delayed placement of composite and double application of single-bottle adhesives on microleakage of composite restorations.

    PubMed

    Shafiei, Fereshteh; Kiomarsi, Nazanin; Alavi, Ali Asghar

    2011-01-01

    This study evaluated the effect of delayed placement of composite and double application of adhesive on microleakage of two-step, total-etch (single-bottle) adhesives. Standard Class V cavities were prepared in 140 sound premolars and randomly assigned into 10 groups (n = 14). Excite, Optibond Solo Plus, and Adper Scotchbond Multi-Purpose (as a control) were used. After the first layer of single-bottle adhesive was photocured, the adhesive was reapplied and photocured in four of the groups. A microhybrid composite was applied in five of the groups immediately after the adhesive was photocured; in the other five groups, the composite was placed after a three-minute delay. After 24 hours of storage in distilled water and thermocycling, the samples were placed in 1% methylene blue. All samples then were sectioned longitudinally and evaluated for microleakage at the occlusal and gingival margins under a stereomicroscope at 20x magnification. Data were analyzed using nonparametric tests. Delayed placement of composite significantly increased leakage at the gingival margins when single-bottle adhesives were used (p < 0.05). Double application of the single-bottle adhesives significantly reduced leakage at the gingival margin when placement of the composite was delayed. There was no significant difference between single and double application when the composite was placed immediately (p < 0.05).

  5. Stomatal responses to vapour pressure deficit are regulated by high speed gene expression in angiosperms.

    PubMed

    McAdam, Scott A M; Sussmilch, Frances C; Brodribb, Timothy J

    2016-03-01

    Plants dynamically regulate water use by the movement of stomata on the surface of leaves. Stomatal responses to changes in vapour pressure deficit (VPD) are the principal regulator of daytime transpiration and water use efficiency in land plants. In angiosperms, stomatal responses to VPD appear to be regulated by the phytohormone abscisic acid (ABA), yet the origin of this ABA is controversial. After a 20 min exposure of plants, from three diverse angiosperm species, to a doubling in VPD, stomata closed, foliar ABA levels increased and the expression of the gene encoding the key, rate-limiting carotenoid cleavage enzyme (9-cis-epoxycarotenoid dioxygenase, NCED) in the ABA biosynthetic pathway was significantly up-regulated. The NCED gene was the only gene in the ABA biosynthetic pathway to be up-regulated over the short time scale corresponding to the response of stomata. The closure of stomata and rapid increase in foliar ABA levels could not be explained by the release of ABA from internal stores in the leaf or the hydrolysis of the conjugate ABA-glucose ester. These results implicate an extremely rapid de novo biosynthesis of ABA, mediated by a single gene, as the means by which angiosperm stomata respond to natural changes in VPD. PMID:26353082

  6. Progress in hollow core photonic crystal fiber for atomic vapour based coherent optics

    NASA Astrophysics Data System (ADS)

    Bradley, T. D.; Wang, Y. Y.; Alharbi, M.; Fourcade Dutin, C.; Mangan, B. J.; Wheeler, N. V.; Benabid, F.

    2012-03-01

    We report on progress in different hollow core photonic crystal fiber (HC-PCF) design and fabrication for atomic vapor based applications. We have fabricated a Photonic bandgap (PBG) guiding HC-PCF with a record loss of 107dB/km at 785nm in this class of fiber. A double photonic bandgap (DPBG) guiding HC-PCF with guidance bands centred at 780nm and 1064nm is reported. A 7-cell 3-ring Kagome HC-PCF with hypocycloid core is reported, the optical loss at 780nm has been reduced to 70dB/km which to the best of our knowledge is the lowest optical loss reported at this wavelength using HC-PCF. Details on experimental loading of alkali metal vapours using a far off red detuned laser are reported. This optical loading has been shown to decrease the necessary loading time for Rb into the hollow core of a fiber. The quantity of Rb within the fiber core has been enhanced by a maximum of 14% through this loading procedure.

  7. Eliminating mass-fractionation effects on U-Pb isochron ages without double spiking

    NASA Astrophysics Data System (ADS)

    Ludwig, Kenneth R.

    2001-09-01

    The utility of uranium-lead isochrons for dating rocks with a restricted range in U/Pb is limited by any uncertainty in the mass fractionation of the analysis. Double spiking (TIMS) or thallium normalization (ICP-MS) remove much of this limitation, as does the method of Getty and DePaolo (1995) for very young rocks. Optimal use of the 3-D "Total Pb/U isochron," however, is extremely simple to apply, requires only single-spiked TIMS analyses, and essentially eliminates fractionation-related age imprecision for rocks of any age.

  8. Quantitative effect of initial current rise on pumping the double-pulsed copper chloride laser

    NASA Technical Reports Server (NTRS)

    Vetter, A. A.

    1977-01-01

    The laser energy at optimum time delay of a double-pulsed CuCl laser was experimentally determined to be a logarithmic function of the initial current rise of the pumping pulse over the total circuit inductance range 1 to 12 microhenrys. The minimum delay was found to decrease with initial current rise, which implies that faster rising current pulses are more efficient at pumping copper atoms from the ground state to the upper laser level because lasing threshold occurs with a higher population in the lower laser level.

  9. Shape and pairing fluctuation effects on neutrinoless double beta decay nuclear matrix elements.

    PubMed

    López Vaquero, Nuria; Rodríguez, Tomás R; Egido, J Luis

    2013-10-01

    Nuclear matrix elements (NME) for the most promising candidates to detect neutrinoless double beta decay have been computed with energy density functional methods including deformation and pairing fluctuations explicitly on the same footing. The method preserves particle number and angular momentum symmetries and can be applied to any decay without additional fine tunings. The finite range density dependent Gogny force is used in the calculations. An increase of 10%-40% in the NME with respect to the ones found without the inclusion of pairing fluctuations is obtained, reducing the predicted half-lives of these isotopes.

  10. Mapping of the Marangoni effect in soap films using Young's double-slit experiment

    NASA Astrophysics Data System (ADS)

    Emile, Janine; Emile, Olivier

    2013-10-01

    We report on the thickness variation measurement of a soap film due to a local perturbation, using Young's double-slit experiment configuration. We map a laser-heated deformation of a vertical free-standing draining thin soap film using the differential change of optical path in the interferometer. The experiment has a resolution of about 0.1 nm and enables to follow the liquid flow dynamics. We evidence a bottleneck formation in the heated region of the film that perturbs the usual flow. Such an experimental set-up could then be adapted to measure other tiny variations in fluctuating hydrodynamics such as capillary waves for example.

  11. The effect of radial pressure force on rotating double tearing mode in compressible plasmas

    NASA Astrophysics Data System (ADS)

    Wang, Xian-Qu; Xiong, Guo-Zhen; Li, Xiao-Qing

    2016-05-01

    The role of radial pressure force in the interlocking dynamics of double tearing modes (DTMs) is investigated by force balance analysis based on the compressible magnetohydrodynamics (MHD) model. It is found that the stability of symmetric DTMs is dominated by the radial pressure force rather than the field line bending force. Owing to the compressibility of rotating plasmas, unbalanced radial forces can just result in the rotating islands drift toward each other in the radial direction but do not trigger the explosive growth of the mode in the interlocking process, which is different from that of antisymmetric DTM without flow.

  12. Post heat treatment effects on double layer metal structures for VLSI applications

    NASA Technical Reports Server (NTRS)

    Wade, T. E.; Trotter, J. D.

    1978-01-01

    The realization of high yield double layer metal systems using wet chemistry processes and the ability to extend yields beyond that attainable with wet chemistry by means of post sintering processes at temperatures below 500 C for potential applications in very large scale integration structures were studied. Yields in excess of 98% and average total contact resistance of less than 150 ohms and 200 ohms were realized for a series of 560 vias of 0.5 X 0.5 mils and 0.2 X 0.2 mils in size, respectively.

  13. Condensation of water vapour on moss-dominated biological soil crust, NW China

    NASA Astrophysics Data System (ADS)

    Wang, Xin-Ping; Pan, Yan-Xia; Hu, Rui; Zhang, Ya-Feng; Zhang, Hao

    2014-03-01

    Characteristics of water vapour condensation, including the onset, duration, and amount of water vapour condensation on moss-dominated biological soil crust (BSC) and dune sand were studied under simulated conditions with varying air temperature and relative humidity. The simulations were performed in a plant growth chamber using an electronic balance recording the weight of condensation. There was a positive linear correlation between the water vapour condensation and relative humidity while the mean temperature was negatively linearly related to amounts of water vapour condensation for both soil surfaces. The amount of water vapour condensation on BSC and dune sand can be described by the difference between air temperature and dew point with an exponential function, indicating that when the difference of air temperature and dew point exceeds a value of 35.3◦C, there will be zero water vapour condensed on BSC. In contrast, when the difference of air temperature and dew point exceeds a value of 20.4◦C, the water vapour condensation will be zero for dune sand. In general, when the air is fully saturated with water and the dew point is equal to the current air temperature, the water vapour condensed on BSC attained its maximum value of 0.398 mm, whereas it was 0.058 mm for dune sand. In comparison, water vapour condensed on BSC was at a relatively high temperature and low relative humidity, while we did not detect water vapour condensation on the dune sand under the similar conditions. Physical and chemical analyses of the samples pointed to a greater porosity, high content of fine particles, and high salinity for BSC compared to the dune sand. These results highlight that soil physicochemical properties are the likely factors influencing the mechanism of water vapour condensation under specific meteorological conditions, as onset was earlier and the duration was longer for water vapour condensation on BSC in comparison with that of dune sand. This contributed to

  14. Effect of radiotherapy on moderate and severe thyroid associated ophthalmopathy: a double blind and self-controlled study

    PubMed Central

    Wu, Yujie; Tong, Boding; Luo, Yongheng; Xie, Guiyuan; Xiong, Wei

    2015-01-01

    Objective: The effect of radiotherapy on moderate and severe Thyroid associated ophthalmopathy (TAO) was evaluated by various objective and quantitative indexes including T2 signal intensity ratios of orbital MRI inferior rectus and ipsilateral temporal muscle (T2SIR), extraocular muscles (EOM) volume, and the degree of exophthalmos using clinical research with prospective, randomized, double blind, self controlled. Methods: The patients with TAO who in the moderate and severe active period and had similar double eyes condition in the Outpatient Department of Ophthalmology of Xiangya No. 2 Hospital of Central South University from 2011.2 to 2014.2 were selected as objects in this study. The related body check was finished after the research group was built. For the object, one eye of patient having random radiotherapy was chosen as the experimental eye. The other eye in the same patient with pseudo radiotherapy (merely known by operator, doctors in department of ophthalmology and patients were double blind) was selected as the control eye. The radiotherapy plan was made by the operator according to the CT results. The T2 signal intensity ratios of orbital MRI inferior rectus and ipsilateral temporal muscle (T2SIR), extraocular muscles (EOM) volume, and the exophthalmos degree was compared by MRI check to evaluate the effect of radiotherapy. Results: The T2 signal intensity ratios of orbital MRI inferior rectus and ipsilateral temporal muscle (T2SIR), extraocular muscles (EOM) volume, and the exophthalmos degree between both eyes (experimental and control eyes) had significant differences and these data had statistical significance. Conclusions: The treatment of radiotherapy is effective for the TAO in the moderate and severe active period. PMID:25932139

  15. Augmenting the antitumor effect of TRAIL by SOCS3 with double-regulated replicating oncolytic adenovirus in hepatocellular carcinoma.

    PubMed

    Wei, Rui-Cheng; Cao, Xin; Gui, Jing-Hua; Zhou, Xiu-Mei; Zhong, Dan; Yan, Qiao-Lin; Huang, Wei-Dan; Qian, Qi-Jun; Zhao, Feng-Li; Liu, Xin-Yuan

    2011-09-01

    Aberrant JAK/STAT3 pathway has been reported to be related to hepatocellular carcinoma (HCC) in many cell lines. In this study, a double-regulated oncolytic adenovirus vector that can replicate and induce a cytopathic effect in alpha-fetoprotein (AFP)-positive HCC cell lines with p53 dysfunction was successfully constructed. Two therapeutic genes, suppressor of cytokine signaling 3 (SOCS3) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), were chosen and incorporated into this vector system, respectively. The combined treatment of AFP-D55-SOCS3 and AFP-D55-TRAIL (2:3 ratio) exhibited potent antitumor activity in AFP-positive HCC cell lines compared with any other treatment both in vitro and in vivo. Specific replication and low progeny yield in AFP-positive HCC cell lines rendered these double-regulated oncolytic adenoviruses remarkably safe. Our data demonstrated that restoration of SOCS3, which inhibits the JAK/STAT3 pathway, by AFP-D55-SOCS3 not only could antagonize HCC therapeutic resistance to TRAIL and adenoviruses, but could also induce cell cycle arrest in HCC cell lines. SOCS3 could down-regulate Cyclin D1 and anti-apoptotic proteins such as XIAP, Survivin, Bcl-xL, and Mcl-1, which are responsible for the synergistic inhibitory effects of AFP-D55-SOCS3 and AFP-D55-TRAIL. Dual gene and double-regulated oncolytic adenoviruses may provide safety and excellent antitumor effects for liver cancer, which is the advantage of a cancer-targeting gene virotherapy strategy. PMID:21361790

  16. Development of effective power supply using electric double layer capacitor for static magnetic field coils in fusion plasma experiments.

    PubMed

    Inomoto, M; Abe, K; Yamada, T; Kuwahata, A; Kamio, S; Cao, Q H; Sakumura, M; Suzuki, N; Watanabe, T; Ono, Y

    2011-02-01

    A cost-effective power supply for static magnetic field coils used in fusion plasma experiments has been developed by application of an electric double layer capacitor (EDLC). A prototype EDLC power supply system was constructed in the form of a series LCR circuit. Coil current of 100 A with flat-top longer than 1 s was successfully supplied to an equilibrium field coil of a fusion plasma experimental apparatus by a single EDLC module with capacitance of 30 F. The present EDLC power supply has revealed sufficient performance for plasma confinement experiments whose discharge duration times are an order of several seconds. PMID:21361590

  17. A randomized, double-blind comparison of the effectiveness of environmental cleaning between infection control professionals and environmental service workers.

    PubMed

    Xu, Hong; Jin, Hui; Zhao, Lan; Wei, Xiaojun; Hu, Liangen; Shen, Linhai; Wei, Lingya; Xie, Lijun; Kong, Qingxin; Wang, Yinghong; Ni, Xiaoping

    2015-03-01

    The hospital environment is a reservoir for pathogens, and environmental service workers (ESWs) play an important role in infection prevention. A randomized, double-blind comparison was carried out in a 23-bed intensive care unit of a traditional Chinese medical-Western medical hospital. Aerobic colony counts (ACC) and methicillin-resistant Staphylococcus aureus (MRSA) were used to compare the effectiveness of environmental cleaning between infection control professionals and ESWs. The results suggest that high-touch surfaces around MRSA patients are often not sufficiently cleaned and are even cross-contaminated by ESWs after cleaning. Further educational intervention is needed for improvement of environmental cleaning.

  18. Effect of dipole-dipole interaction on self-control magnetization oscillation in double-domain nanomagnets

    NASA Astrophysics Data System (ADS)

    Gao, Y. J.; Guo, Y. J.; Liu, J.-M.

    2012-03-01

    A double-domain model with long-range dipole-dipole interaction is proposed to investigate the self-oscillation of magnetization in nano-magnetic systems driven by self-controlled spin-polarized current. The dynamic behavior of magnetization oscillation is calculated by a modified Landau-Lifshitz-Gilbert equation in order to evaluate the effects of the long-range dipole-dipole interaction. While the self-oscillation of magnetization can be maintained substantially, several self-oscillation regions are experienced as the dipole-dipole interaction increases gradually.

  19. Millimeter wave mixing using plasmon and bolometric response in a double-quantum-well field-effect transistor

    NASA Astrophysics Data System (ADS)

    Lee, Mark; Wanke, M. C.; Reno, J. L.

    2005-01-01

    Heterodyne mixing characteristics of a double-quantum-well field-effect transistor (DQW FET) from 94 to 145GHz are reported. The DQW FET exhibits two physically distinct mixing responses. Near pinch-off, the device behaves as a broadband bolometric mixer with intermediate frequency (IF) bandwidth of 620MHz. Away from pinch-off it shows an electrically tunable resonant plasmon response. Mixing on a plasmon resonance yields an IF with significant harmonic distortion, signaling a complicated nonlinear mechanism, and shows a wide IF bandwidth >2GHz.

  20. Effect of the amplitude of vibrations on the pull-in instability of double-sided actuated microswitch resonators

    NASA Astrophysics Data System (ADS)

    Sedighi, H. M.; Shirazi, K. H.; Changizian, M.

    2015-03-01

    This paper exhibits the effect of the amplitude of vibrations on the pull-in instability and nonlinear natural frequency of a double-sided actuated microswitch by using a nonlinear frequency-amplitude relationship. The nonlinear governing equation of the microswitch pre-deformed by an electric field includes even and odd nonlinearities with a quintic nonlinear term. The study is performed by a new analytical method called the Hamiltonian approach (HA). It is demonstrated that the first term in series expansions is sufficient to produce an acceptable solution. Results obtained by numerical methods validate the soundness of the asymptotic procedure.

  1. Effects of unreasonable pay discrepancies for under- and overpayment on double demotivation.

    PubMed

    Carr, S C; McLoughlin, D; Hodgson, M; MacLachlan, M

    1996-11-01

    The "double demotivation" hypothesis that pay discrepancies decrease work motivation among both lower and higher paid groups was tested in two experiments. In experiment 1, 70 Australian undergraduates received either $1 or $2 to work on an intrinsically rewarding puzzle, with or without knowledge of what amount other participants were receiving. A comparison of participants with a no-payment control showed that participants exhibited significantly reduced intrinsic motivation (seconds spent interacting with the puzzle during a free-choice period) when they knew that they were being under- or overpaid. In experiment 2, 126 occupationally matched Australian workers receiving wages equal to, lower than, or higher than those of counterparts reported their level of job satisfaction and whether they would stay on the job, change jobs, or retire, if given the financial opportunity. Compared with equitably paid workers, employees who felt they were being under- or overpaid reported lower job satisfaction and greater readiness to change jobs. The results provide experimental support for double demotivation, which is relevant not only to international development cooperation but also to Western enterprise bargaining, merit pay, and minority groups in the multicultural workplace.

  2. Doubled CO2 Effects on NO(y) in a Coupled 2D Model

    NASA Technical Reports Server (NTRS)

    Rosenfield, J. E.; Douglass, A. R.

    1998-01-01

    Changes in temperature and ozone have been the main focus of studies of the stratospheric impact of doubled CO2. Increased CO2 is expected to cool the stratosphere, which will result in increases in stratospheric ozone through temperature dependent loss rates. Less attention has been paid to changes in minor constituents which affect the O3 balance and which may provide additional feedbacks. Stratospheric NO(y) fields calculated using the GSFC 2D interactive chemistry-radiation-dynamics model show significant sensitivity to the model CO2. Modeled upper stratospheric NO(y) decreases by about 15% in response to CO2 doubling, mainly due to the temperature decrease calculated to result from increased cooling. The abundance of atomic nitrogen, N, increases because the rate of the strongly temperature dependent reaction N + O2 yields NO + O decreases at lower temperatures. Increased N leads to an increase in the loss of NO(y) which is controlled by the reaction N + NO yields N2 + O. The NO(y) reduction is shown to be sensitive to the NO photolysis rate. The decrease in the O3 loss rate due to the NO(y) changes is significant when compared to the decrease in the O3 loss rate due to the temperature changes.

  3. The double-gradient magnetic instability: Stabilizing effect of the guide field

    NASA Astrophysics Data System (ADS)

    Korovinskiy, D. B.; Divin, A. V.; Erkaev, N. V.; Semenov, V. S.; Artemyev, A. V.; Ivanova, V. V.; Ivanov, I. B.; Lapenta, G.; Markidis, S.; Biernat, H. K.

    2015-01-01

    The role of the dawn-dusk magnetic field component in stabilizing of the magnetotail flapping oscillations is investigated in the double-gradient model framework (Erkaev et al., Phys. Rev. Lett. 99, 235003 (2007)), extended for the magnetotail-like configurations with non-zero guide field By. Contribution of the guide field is examined both analytically and by means of linearized 2-dimensional (2D) and non-linear 3-dimensional (3D) MHD modeling. All three approaches demonstrate the same properties of the instability: stabilization of current sheet oscillations for short wavelength modes, appearing of the typical (fastest growing) wavelength λpeak of the order of the current sheet width, decrease of the peak growth rate with increasing By value, and total decay of the mode for By˜0.5 in the lobe magnetic field units. Analytical solution and 2D numerical simulations claim also the shift of λpeak toward the longer wavelengths with increasing guide field. This result is barely visible in 3D simulations. It may be accounted for the specific background magnetic configuration, the pattern of tail-like equilibrium provided by approximated solution of the conventional Grad-Shafranov equation. The configuration demonstrates drastically changing radius of curvature of magnetic field lines, Rc. This, in turn, favors the "double-gradient" mode (λ > Rc) in one part of the sheet and classical "ballooning" instability (λ < Rc) in another part, which may result in generation of a "combined" unstable mode.

  4. Ammonia in simulated Hanford double-shell tank wastes: Solubility and effects on surface tension

    SciTech Connect

    Norton, J.D.; Pederson, L.R.

    1994-09-01

    Radioactive and wastes left from defense materials production activities are temporarily stored in large underground tanks at the Hanford Site in south central Washington State (Tank Waste Science Panel 1991). Some of these wastes are in the form of a thick slurry (``double-shell slurry``) containing sodium nitrate, sodium nitrite, sodium aluminate, sodium hydroxide, sodium carbonate, organic complexants and buffering agents, complexant fragments and other minor components (Herting et al. 1992a; Herting et al. 1992b; Campbell et al. 1994). As a result of thermal and radiolytic processes, a number of gases are known to be produced by some of these stored wastes, including ammonia, nitrous oxide, nitrogen, hydrogen, and methane (Babad et al. 1991; Ashby et al. 1992; Meisel et al. 1993; Ashby et al. 1993; Ashby et al. 1994; Bryan et al. 1993; US Department of Energy 1994). Before the emplacement of a mixer pump, these gases were retained in and periodically released from Tank 241-SY-101, a double-shell tank at the Hanford Site (Babad et al. 1992; US Department of Energy 1994). Gases are believed to be retained primarily in the form of bubbles attached to solid particles (Bryan, Pederson, and Scheele 1992), with very little actually dissolved in the liquid. Ammonia is an exception. The relation between the concentration of aqueous ammonia in such concentrated, caustic mixtures and the ammonia partial pressure is not well known, however.

  5. Single- and double-slit collimating effects on fast-atom diffraction spectra

    NASA Astrophysics Data System (ADS)

    Gravielle, M. S.; Miraglia, J. E.

    2016-09-01

    Diffraction patterns produced by fast He atoms grazingly impinging on a LiF(0 0 1) surface are investigated focusing on the influence of the beam collimation. Single- and double-slit collimating devices situated in front of the beam source are considered. To describe the scattering process we use the Surface Initial Value Representation (SIVR) approximation, which is a semi-quantum approach that incorporates a realistic description of the initial wave packet in terms of the collimating parameters. Our initial wave-packet model is based on the Van Cittert-Zernike theorem. For a single-slit collimation the width of the collimating aperture controls the shape of the azimuthal angle distribution, making different interference mechanisms visible, while the length of the slit affects the polar angle distribution. Additionally, we found that by means of a double-slit collimation it might be possible to obtain a wide polar angle distribution, which is associated with a large spread of the initial momentum perpendicular to the surface, derived from the uncertainty principle. It might be used as a simple way to probe the surface potential for different normal energies.

  6. Renormalization shielding effect on the Wannier-ridge mode for double-electron continua in partially ionized dense hydrogen plasmas

    NASA Astrophysics Data System (ADS)

    Lee, Myoung-Jae; Jung, Young-Dae

    2016-01-01

    The influence of renormalization shielding on the Wannier threshold law for the double-electron escapes by the electron-impact ionization is investigated in partially ionized dense plasmas. The renormalized electron charge and Wannier exponent are obtained by considering the equation of motion in the Wannier-ridge including the renormalization shielding effect. It is found that the renormalization shielding effect reduces the magnitude of effective electron charge, especially, within the Bohr radius in partially ionized dense plasmas. The maximum position of the renormalized electron charge approaches to the center of the target atom with an increase of the renormalization parameter. In addition, the Wannier exponent increases with an increase of the renormalization parameter. The variations of the renormalized electron charge and Wannier exponent due to the renormalization shielding effect are also discussed.

  7. Exploring new scaling regimes for streaming potential and electroviscous effects in a nanocapillary with overlapping electric double layers.

    PubMed

    Das, Siddhartha; Guha, Arnab; Mitra, Sushanta K

    2013-12-01

    In this paper, we unravel new scaling regimes for streaming potential and electroviscous effects in a nanocapillary with thick overlapping Electric Double Layers (EDLs). We observe that the streaming potential, for a given value of the capillary zeta (ζ) potential, varies with the EDL thickness and a dimensionless parameter R, quantifying the conduction current. Depending on the value of R, variation of the streaming potential with the EDL thickness demonstrates distinct scaling regimes: one can witness a Quadratic Regime where the streaming potential varies as the square of the EDL thickness, a Weak Regime where the streaming potential shows a weaker variation with the EDL thickness, and a Saturation Regime where the streaming potential ceases to vary with the EDL thickness. Effective viscosity, characterizing the electroviscous effect, obeys the variation of the streaming potential for smaller EDL thickness values; however, for larger EDL thickness the electroosmotic flow profile dictates the electroviscous effect, with insignificant contribution of the streaming potential.

  8. Performance evaluation of a solar ejector-vapour compression cycle for cooling application

    NASA Astrophysics Data System (ADS)

    Megdouli, K.; Elakhdar, M.; Nahdi, E.; Kairouani, L.; Mhimid, A.

    2015-04-01

    This study deals with the performance of the ejector-vapour compression cycle assisted by solar. The effect of operating conditions on the combined cycle performance is examined. Also, a comparison of the system performance with environment friendly refrigerants (R134a, R600, R123, R141b, R142b, R152a, R290, and R245fa) is made. This performance is calculated using an empirical correlation. Thermodynamic properties of functioning fluids are obtained with package REFPROP 8. Using the typical meteorological year file containing the weather data of the city of Tunis, the system performance is computed for three collector types. The theoretical results show that the R290 offers the highest coefficient of performance, COP=3.75, for generator temperature TB = 78°C, condenser temperature Tc = 30°C and the intercooler temperature Te = 15°C.

  9. Photoluminescent Si/SiOx nanoparticle network by near atmospheric plasma-enhanced chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Yang, Q. Y.; Wang, D. X.; Guo, Y.; Ding, K.; Xu, J. Z.; Shi, J. J.; Zhang, J.

    2011-11-01

    A very fast and simple near atmospheric plasma-enhanced chemical vapour deposition method modulated by a pulsed negative bias voltage is newly developed to yield a Si/SiOx nanoparticle-linked network structure, which emitted enhanced 410 nm photoluminescence (PL) at room temperature. Hydrogen dissociation, oxidation and polarization of the silane plasma-generated active particles could be tuned by the magnitude of bias voltage. The porosity and oxidation of this network structure and the intensity of its PL spectrum at 410 nm were observed to increase with the bias voltage. The large surface area of the Si/SiOx nanoparticle-linked network intensified the radiative recombination centre effect and caused the PL emission enhancement.

  10. Cross sections and transport of O- in H2O vapour at low pressures

    NASA Astrophysics Data System (ADS)

    Stojanović, Vladimir; Raspopović, Zoran; Marić, Dragana; Petrović, Zoran Lj.

    2015-03-01

    The transport properties of O- ions in water vapour drifting in DC fields were obtained by using the Monte Carlo simulation technique with the scattering cross section sets assessed on the basis of Denpoh and Nanbu's technique and available experimental data. A swarm method is applied to determine recommended cross section set. For the first time in this work we present the transport parameters for the conditions of low to moderate reduced electric fields E/ N ( N is gas density) accounting for the effect of non-conservative collisions. The data are applicable in the limit of low pressures where cluster formation does not affect the transport or may be applied at higher pressures together with a model of cluster formation kinetics.

  11. The boiling liquid expanding vapour explosion (BLEVE): mechanism, consequence assessment, management.

    PubMed

    Abbasi, Tasneem; Abbasi, S A

    2007-03-22

    Among the most devastating of accidents likely in chemical process industry is the boiling liquid expanding vapour explosion (BLEVE). It is accompanied by highly destructive blast waves and missiles. In most situations there is also a fireball or a toxic gas cloud. The damaging effect of BLEVEs is reflected in the fact that the 80-odd major BLEVEs that have occurred between 1940 and 2005 have claimed over a 1000 lives and have injured over 10,000 persons besides harming property worth billions of dollars. Release of toxic chemicals like chlorine and phosgene from BLEVEs have damaged large chunks of areas surrounding the BLEVE site. This paper presents an overview of the mechanism, the causes, the consequences, and the preventive strategies associated with BLEVEs. PMID:17113225

  12. A group contribution method for estimating the vapour pressures of α-pinene oxidation products

    NASA Astrophysics Data System (ADS)

    Capouet, M.; Müller, J.-F.

    2006-05-01

    A prediction method based on group contribution principles is proposed for estimating the vapour pressure of α-pinene oxidation products. Temperature dependent contributions are provided for the following chemical groups: carbonyl, nitrate, hydroxy, hydroperoxy, acyl peroxy nitrate and carboxy. On the basis of observed vapour pressure differences between isomers of diols and dinitrates, a simple refinement is introduced in the method to account for the influence of substitutions on the vapour pressure for alcohols and nitrates. The vapour pressures predicted with this new method have been compared with the predictions from UNIFAC (Asher et al., 2002). Given the large uncertainties of the vapour pressure data for the least volatile compounds, further experimental studies of subcooled vapour pressures of multifunctional compounds at ambient temperatures are required for better parameterizations. Among the α-pinene products identified to date, pinic acid and hydroxy pinonic acid are predicted to be the least volatile compounds, with estimated vapour pressures of 3×10-6 torr and 6×10-7 torr, respectively. The vapour pressure of the other primary products range from 10-5 to 10-3 torr, with hydroxy hydroperoxides presenting the lowest values. Noting that multifunctional carboxylic acids, in particular pinic acid, are believed to be mostly present as dimers in laboratory conditions, we suggest that the partial vapour pressure of the pinic acid dimer should be close to the experimental subcooled vapour pressure for pinic acid (estimated at ~10-6 torr) due to its large contribution to the total concentration (dimer+monomer) in experimental conditions.

  13. Predicting the frequency of occurrence of visible water vapour plumes at proposed industrial sites

    NASA Astrophysics Data System (ADS)

    Sturman, Andrew; Zawar-Reza, Peyman

    2011-04-01

    Although they may have no direct health impacts, visible water vapour plumes can be of concern to the local population in the vicinity of major industrial plant developments. In this paper, prediction of the occurrence of visible plumes at proposed industrial sites is assessed using the case study of a planned major cement plant in New Zealand. The aim of the investigation was to use a simple but robust approach to estimate the frequency of occurrence of visible water vapour plumes emitted by a proposed plant, as well as their likely dimensions. Input data consisted of information relating to the raw materials used in the production process, as well as stack design parameters. The atmospheric mesoscale model TAPM (The Air Pollution Model) was run for the whole of 2007 to predict ambient conditions in the vicinity of the site. A simple model was then applied to predict visible water vapour plume development under a range of emission rates for the whole year, as well as by season. Predictions were provided for the whole year, allowing for the fact that visible plumes would not be a problem at night and during rain. Model results showed that with three different emission rates (design, intermediate and worst-case) the occurrence of visible plumes at the proposed stack site is likely to be infrequent (less than 0.1% of hours per annum at 20 m from the stack under design conditions). When they do occur, the plumes are expected to be relatively small (a few tens of metres in length/diameter). Visible plume occurrence in winter is predicted to increase to almost 0.2% of the time under the design emission rate of 8.6 kg s -1. The main effect is expected to be on visible plume development within 50 m of the stack, while further away from the stack any visible plume development is expected to be negligible. The sensitivity of visible plume development to varying stack water discharge rates is investigated, along with the specific meteorological conditions under which visible

  14. Hierarchically arranged helical fibre actuators driven by solvents and vapours.

    PubMed

    Chen, Peining; Xu, Yifan; He, Sisi; Sun, Xuemei; Pan, Shaowu; Deng, Jue; Chen, Daoyong; Peng, Huisheng

    2015-12-01

    Mechanical responsiveness in many plants is produced by helical organizations of cellulose microfibrils. However, simple mimicry of these naturally occurring helical structures does not produce artificial materials with the desired tunable actuations. Here, we show that actuating fibres that respond to solvent and vapour stimuli can be created through the hierarchical and helical assembly of aligned carbon nanotubes. Primary fibres consisting of helical assemblies of multiwalled carbon nanotubes are twisted together to form the helical actuating fibres. The nanoscale gaps between the nanotubes and micrometre-scale gaps among the primary fibres contribute to the rapid response and large actuation stroke of the actuating fibres. The compact coils allow the actuating fibre to rotate reversibly. We show that these fibres, which are lightweight, flexible and strong, are suitable for a variety of applications such as energy-harvesting generators, deformable sensing springs and smart textiles. PMID:26367106

  15. Hierarchically arranged helical fibre actuators driven by solvents and vapours

    NASA Astrophysics Data System (ADS)

    Chen, Peining; Xu, Yifan; He, Sisi; Sun, Xuemei; Pan, Shaowu; Deng, Jue; Chen, Daoyong; Peng, Huisheng

    2015-12-01

    Mechanical responsiveness in many plants is produced by helical organizations of cellulose microfibrils. However, simple mimicry of these naturally occurring helical structures does not produce artificial materials with the desired tunable actuations. Here, we show that actuating fibres that respond to solvent and vapour stimuli can be created through the hierarchical and helical assembly of aligned carbon nanotubes. Primary fibres consisting of helical assemblies of multiwalled carbon nanotubes are twisted together to form the helical actuating fibres. The nanoscale gaps between the nanotubes and micrometre-scale gaps among the primary fibres contribute to the rapid response and large actuation stroke of the actuating fibres. The compact coils allow the actuating fibre to rotate reversibly. We show that these fibres, which are lightweight, flexible and strong, are suitable for a variety of applications such as energy-harvesting generators, deformable sensing springs and smart textiles.

  16. Light-induced chemical vapour deposition painting with titanium dioxide

    NASA Astrophysics Data System (ADS)

    Halary-Wagner, E.; Bret, T.; Hoffmann, P.

    2003-03-01

    Light-induced chemical vapour deposits of titanium dioxide are obtained from titanium tetra-isopropoxide (TTIP) in an oxygen and nitrogen atmosphere with a long pulse (250 ns) 308 nm XeCl excimer laser using a mask projection set-up. The demonstrated advantages of this technique are: (i) selective area deposition, (ii) precise control of the deposited thickness and (iii) low temperature deposition, enabling to use a wide range of substrates. A revolving mask system enables, in a single reactor load, to deposit shapes of controlled heights, which overlap to build up a complex pattern. Interferential multi-coloured deposits are achieved, and the process limitations (available colours and resolution) are discussed.

  17. Atmospheric pressure vapour phase decomposition: a proof of principle.

    PubMed

    Cinosi, Amedeo; Andriollo, Nunzio; Tibaldi, Francesca; Monticelli, Damiano

    2012-11-15

    In the present work we demonstrated that the digestion of difficult matrices (high boiling petrochemical fractions and distillation bottoms) can be achieved by oxidation with nitric acid vapours at atmospheric pressure employing simple laboratory glassware. The application of this procedure as a digestion method prior to Total Reflection X-Ray Fluorescence (TXRF) is presented, although the employment of other detection techniques may be foreseen. The method ensured a fast, less than half an hour, treatment time and detection limits in the range 20-100 μg/kg for As, Bi, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, Zn, whereas higher values were obtained for Ba, Ca, K, P, Rh, Ti and V (0.3-3 mg/kg). The potentialities and limitations of this procedure were discussed: the application to a broad range of matrices may be foreseen. PMID:23158304

  18. Atmospheric pressure vapour phase decomposition: a proof of principle.

    PubMed

    Cinosi, Amedeo; Andriollo, Nunzio; Tibaldi, Francesca; Monticelli, Damiano

    2012-11-15

    In the present work we demonstrated that the digestion of difficult matrices (high boiling petrochemical fractions and distillation bottoms) can be achieved by oxidation with nitric acid vapours at atmospheric pressure employing simple laboratory glassware. The application of this procedure as a digestion method prior to Total Reflection X-Ray Fluorescence (TXRF) is presented, although the employment of other detection techniques may be foreseen. The method ensured a fast, less than half an hour, treatment time and detection limits in the range 20-100 μg/kg for As, Bi, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, Zn, whereas higher values were obtained for Ba, Ca, K, P, Rh, Ti and V (0.3-3 mg/kg). The potentialities and limitations of this procedure were discussed: the application to a broad range of matrices may be foreseen.

  19. 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.

  20. Hierarchically arranged helical fibre actuators driven by solvents and vapours.

    PubMed

    Chen, Peining; Xu, Yifan; He, Sisi; Sun, Xuemei; Pan, Shaowu; Deng, Jue; Chen, Daoyong; Peng, Huisheng

    2015-12-01

    Mechanical responsiveness in many plants is produced by helical organizations of cellulose microfibrils. However, simple mimicry of these naturally occurring helical structures does not produce artificial materials with the desired tunable actuations. Here, we show that actuating fibres that respond to solvent and vapour stimuli can be created through the hierarchical and helical assembly of aligned carbon nanotubes. Primary fibres consisting of helical assemblies of multiwalled carbon nanotubes are twisted together to form the helical actuating fibres. The nanoscale gaps between the nanotubes and micrometre-scale gaps among the primary fibres contribute to the rapid response and large actuation stroke of the actuating fibres. The compact coils allow the actuating fibre to rotate reversibly. We show that these fibres, which are lightweight, flexible and strong, are suitable for a variety of applications such as energy-harvesting generators, deformable sensing springs and smart textiles.

  1. Effect of NACA Injection Impeller on Mixture Distribution of Double-Row Radial Aircraft Engine

    NASA Technical Reports Server (NTRS)

    Marble, Frank E; Ritter, William K; Miller, Mahlon A

    1945-01-01

    The NACA injection impeller was developed to improve the mixture distribution of aircraft engines by discharging the fuel from a centrifugal supercharger impeller and thus to promote a thorough mixing of fuel and charge air. Experiments with a double-row radial aircraft engine indicated that for the normal range of engine power the NACA injection impeller provided marked improvement in mixture distribution over the standard spray-bar injection system used in the same engine. The mixture distribution at cruising conditions was excellent; at 1200, 1500, and 1700 brake horsepower, the differences between the fuel-air ratios of the richest and the leanest cylinders were reduced to approximately one-third their former values.

  2. Room temperature on-wafer ballistic graphene field-effect-transistor with oblique double-gate

    NASA Astrophysics Data System (ADS)

    Dragoman, Mircea; Dinescu, Adrian; Dragoman, Daniela

    2016-06-01

    We have fabricated and measured ballistic graphene transistors with two oblique gates that can be independently biased. The gates, with lengths of about 30 nm and separated by a distance of about 40 nm, are tilted at 45° with respect to the source and drain electrodes, which are distanced at 190 nm. Electric measurements reveal specific properties of ballistic carrier transport, i.e., nonlinear drain voltage-drain current dependences with saturation regions and negative differential resistance at certain bias voltages. Tens of ballistic transistors with very large transconductances were fabricated on a chip cut from a 4 in. graphene wafer. Such double-gate transistor configurations can be used also as extremely efficient, state-of-the-art photodetectors.

  3. Effects of contaminants on Double-crested Cormorant reproduction in Green Bay, Wisconsin, USA

    USGS Publications Warehouse

    Custer, T.W.; Custer, Christine M.; Stromborg, K.L.; Melancon, M.J.; Adams, N.J.; Slotow, R.H.

    1998-01-01

    In 1994 and 1995, Double-crested Cormorants Phalacrocorax auritus were monitored from egg-laying through 12 days of age at Cat Island, Green Bay, Wisconsin, USA. Sample eggs at hatching were analysed for organochlorines (including total PCBs, PCB congeners, and DDE), hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity in livers of embryos, and eggshell thickness. The number of eggs per nest that hatched and survived to i 2 days of age was estimated to be 2.2 in 1994 and 2.0 in 1995. Hatching success of eggs was not correlated with PCBs, the toxicity of PCBs based on congeners, or EROD activity. Hatching success was correlated with eggshell thickness and negatively correlated with DDE concentrations. Even though the insecticide DDT was banned in the early 1970s, we suggest that DDE concentrations in cormorant eggs in Green Bay are still having an affect on reproduction in this species.

  4. Effects of contaminants on Double-crested Cormorant reproduction in Green Bay, Wisconsin, USA

    USGS Publications Warehouse

    Custer, T.W.; Custer, Christine M.; Stromborg, K.L.; Melancon, M.J.; Adams, N.J.; Slotow, R.H.

    1999-01-01

    In 1994 and 1995, Double-crested Cormorants Phalacrocorax auritus were monitored from egg-laying through 12 days of age at Cat Island, Green Bay, Wisconsin, USA. Sample eggs at hatching were analysed for organochlorines (including total PCBs, PCB congeners, and DDE), hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity in livers of embryos, and eggshell thickness. The number of eggs per nest that hatched and survived to i 2 days of age was estimated to be 2.2 in 1994 and 2.0 in 1995. Hatching success of eggs was not correlated with PCBs, the toxicity of PCBs based on congeners, or EROD activity. Hatching success was correlated with eggshell thickness and negatively correlated with DDE concentrations. Even though the insecticide DDT was banned in the early 1970s, we suggest that DDE concentrations in cormorant eggs in Green Bay are still having an affect on reproduction in this species.

  5. Effective approach to strengthening TiO2 nanotube arrays by using double or triple reinforcements

    NASA Astrophysics Data System (ADS)

    Sun, Mengwei; Yu, Dongliang; Lu, Linfeng; Ma, Weihua; Song, Ye; Zhu, Xufei

    2015-08-01

    Porous anodic TiO2 nanotube arrays (TNTAs) are fragile and also susceptible to be damaged during physical manipulation. Few studies have involved the improvement of the poor interfacial adhesion of TNTAs to the Ti substrate. Here, the poor adhesion of TNTAs was dramatically improved by appending an additional compact layer (ACL) formed at the interface between TNTAs and the Ti substrate. The adhesion of TNTAs with single-ACL increased with the increase of the ACL thickness. Furthermore, the reinforced TNTAs with double-ACL and triple-ACL have been successfully developed for the first time. The experimental results indicated that the critical load of the TNTAs with triple-ACL is roughly 5.8 times higher than that of the untreated TNTAs. The present results may be helpful to assemble less brittle and large area TNTAs for extensive applications.

  6. Importance of non-first-order effects in the (e,3e) double ionization of helium

    SciTech Connect

    Lahmam-Bennani, A.; Duguet, A.; Dal Cappello, C.; Nebdi, H.; Piraux, B.

    2003-01-01

    Angular distributions of the two ejected electrons resulting from the double ionization of helium by electron impact have been measured by means of a multicoincidence multiangle (e,3e) spectrometer at an incident energy of about 0.6 keV and equal outgoing energies E{sub b}=E{sub c}=11 eV. We identify various regimes of kinematical parameters where substantial differences are found with respect to the first-Born convergent close-coupling calculations: an angular shift of the position of the main lobe and the presence of additional lobes. These differences are attributed to high-order contributions in the projectile-target interaction. This conclusion is supported by recent (e,3e) calculations performed within the second-Born approximation.

  7. Spin blocking effect in symmetric double quantum well due to Rashba spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Souma, Satofumi; Ogawa, Matsuto; Sekine, Yoshiaki; Sawada, Atsushi; Koga, Takaaki

    2013-03-01

    We report a theoretical study of the spin-dependent electronic current flowing laterally through the In0.53Ga0.47As/In0.52Al0.48As double quantum well (DQW) structure, where the values of the Rashba spin-orbit parameter αR are opposite in sign but equal in magnitude between the constituent quantum wells. By tuning the channel length of DQW and the magnitude of the externally applied in-plane magnetic field, one can block the transmission of one spin (e.g., spin-up) component, enabling us to obtain a spin-polarized current. Our experimental progress toward realizing the proposed device is also reported. This work was supported by JSPS KAKENHI Grant Number 23360001 and 22104007

  8. A compact quantum correction model for symmetric double gate metal-oxide-semiconductor field-effect transistor

    SciTech Connect

    Cho, Edward Namkyu; Shin, Yong Hyeon; Yun, Ilgu

    2014-11-07

    A compact quantum correction model for a symmetric double gate (DG) metal-oxide-semiconductor field-effect transistor (MOSFET) is investigated. The compact quantum correction model is proposed from the concepts of the threshold voltage shift (ΔV{sub TH}{sup QM}) and the gate capacitance (C{sub g}) degradation. First of all, ΔV{sub TH}{sup QM} induced by quantum mechanical (QM) effects is modeled. The C{sub g} degradation is then modeled by introducing the inversion layer centroid. With ΔV{sub TH}{sup QM} and the C{sub g} degradation, the QM effects are implemented in previously reported classical model and a comparison between the proposed quantum correction model and numerical simulation results is presented. Based on the results, the proposed quantum correction model can be applicable to the compact model of DG MOSFET.

  9. Effect of ion dispersion forces on the electric double layer of colloids: a Monte Carlo simulation study.

    PubMed

    Martín-Molina, Alberto; Ibarra-Armenta, José G; Quesada-Pérez, Manuel

    2009-02-26

    In this work, the effect of ionic dispersion forces on the electric double layer of colloids is evaluated through Monte Carlo simulations. Particularly, the influence of these forces on the zeta-potential (as a representative electrokinetic property) is assessed. Ion polarizability is included in the primitive model with the help of the Lifshitz theory. In this way, ion specificity is not considered by means of phenomenological (and unknown a priori) parameters. Our results reveal that the ionic van der Waals forces are responsible (to some extent) for the specificity of the zeta-potential. In any case, the specific ion effects due to ion polarizability are strongly influenced by ion size. Furthermore, a preliminary study on the effect of ionic dehydration shows how this phenomenon improves the qualitative agreement between experimental data and simulations achieved in considering ionic dispersion forces. PMID:19199701

  10. Effects of naloxone and naltrexone on self-injury: a double-blind, placebo-controlled analysis.

    PubMed

    Barrett, R P; Feinstein, C; Hole, W T

    1989-05-01

    The effects of naloxone hydrochloride (Narcan) and naltrexone hydrochloride (Trexan) on the pervasive self-injury of a 12-year-old autistic and mentally retarded girl were examined. Using separate multiple schedule (A1/B/B') and withdrawal (A-B-A1B-A1) single-subject experimental designs, we investigated the effects of both opiate antagonists in serial fashion under double-blind, placebo-controlled conditions. Results of the two studies showed that self-injury increased during the naloxone trial, whereas a decrease to near zero rates of self-injury was observed following treatment with naltrexone. The differential effect produced by the two drugs was discussed in terms of drug half-life and the operant conditioning theory of extinction. Follow-up data showing near zero rates of self-injury for 22 months following the conclusion of active treatment with naltrexone indicated that the intervention produced a durable result.

  11. The Optical Kerr Effect in Wurtzite GaN-BASED Double Quantum Wells:. Influences of Piezoelectricity and Spontaneous Polarization

    NASA Astrophysics Data System (ADS)

    Zhang, L.

    Taking the influences of piezoelectricity and spontaneous polarization into consideration, the nonlinear optical Kerr effect in a nitride semiconductor coupling double quantum well (DQW) has been theoretically investigated by using the compact density matrix approach and iterative treatment. The electronic eigenstates in a nitride DQW are exactly solved based on the built-in electric field model already constituted in recent reference. The band non-parabolicity effect of nitride heterostructures has been taken into account. A typical wurtzite GaN/AlGaN DQW is chosen to perform numerical calculations. The calculated results reveal that the optical Kerr coefficients sensitively depend on the structural parameters of the coupling DQW system. Moreover, a strong optical Kerr effect can be realized in the nitride DQW by choosing a group of optimum structural parameters and doped fraction.

  12. Effect of surface stress on stress intensity factors of a nanoscale crack via double cantilever beam model.

    PubMed

    Wang, Hua; Li, Xianfang; Tang, Guojin; Shen, Zhibin

    2013-01-01

    This paper studies the influence of surface elasticity on crack growth for a nanoscale crack advance. A crack is modeled as a double cantilever beam with consideration of surface stress. Using the Euler-Bernoulli beam theory incorporating with surface effects, a governing equation of static bending is derived and bending solution of a cantilever nanowire is obtained for a concentrated force at the free end. Based on the viewpoint of energy balance, the elastic strain energy is given and energy release rate is determined. The influences of the Surface stress and the surface elasticity on crack growth are discussed. Obtained results indicate that consideration of the surface effects decreases stress intensity factors or energy release rates. The residual surface tension impedes propagation of a nanoscale crack and apparent fracture toughness of nanoscale materials is effectively enhanced. PMID:23646757

  13. The double-gradient magnetic instability: Stabilizing effect of the guide field

    SciTech Connect

    Korovinskiy, D. B. Semenov, V. S.; Ivanova, V. V.; Divin, A. V.; Erkaev, N. V.; Artemyev, A. V.; Lapenta, G.; Markidis, S.; Biernat, H. K.

    2015-01-15

    The role of the dawn-dusk magnetic field component in stabilizing of the magnetotail flapping oscillations is investigated in the double-gradient model framework (Erkaev et al., Phys. Rev. Lett. 99, 235003 (2007)), extended for the magnetotail-like configurations with non-zero guide field B{sub y}. Contribution of the guide field is examined both analytically and by means of linearized 2-dimensional (2D) and non-linear 3-dimensional (3D) MHD modeling. All three approaches demonstrate the same properties of the instability: stabilization of current sheet oscillations for short wavelength modes, appearing of the typical (fastest growing) wavelength λ{sub peak} of the order of the current sheet width, decrease of the peak growth rate with increasing B{sub y} value, and total decay of the mode for B{sub y}∼0.5 in the lobe magnetic field units. Analytical solution and 2D numerical simulations claim also the shift of λ{sub peak} toward the longer wavelengths with increasing guide field. This result is barely visible in 3D simulations. It may be accounted for the specific background magnetic configuration, the pattern of tail-like equilibrium provided by approximated solution of the conventional Grad-Shafranov equation. The configuration demonstrates drastically changing radius of curvature of magnetic field lines, R{sub c}. This, in turn, favors the “double-gradient” mode (λ > R{sub c}) in one part of the sheet and classical “ballooning” instability (λ < R{sub c}) in another part, which may result in generation of a “combined” unstable mode.

  14. Musicians have enhanced audiovisual multisensory binding: experience-dependent effects in the double-flash illusion.

    PubMed

    Bidelman, Gavin M

    2016-10-01

    Musical training is associated with behavioral and neurophysiological enhancements in auditory processing for both musical and nonmusical sounds (e.g., speech). Yet, whether the benefits of musicianship extend beyond enhancements to auditory-specific skills and impact multisensory (e.g., audiovisual) processing has yet to be fully validated. Here, we investigated multisensory integration of auditory and visual information in musicians and nonmusicians using a double-flash illusion, whereby the presentation of multiple auditory stimuli (beeps) concurrent with a single visual object (flash) induces an illusory perception of multiple flashes. We parametrically varied the onset asynchrony between auditory and visual events (leads and lags of ±300 ms) to quantify participants' "temporal window" of integration, i.e., stimuli in which auditory and visual cues were fused into a single percept. Results show that musically trained individuals were both faster and more accurate at processing concurrent audiovisual cues than their nonmusician peers; nonmusicians had a higher susceptibility for responding to audiovisual illusions and perceived double flashes over an extended range of onset asynchronies compared to trained musicians. Moreover, temporal window estimates indicated that musicians' windows (<100 ms) were ~2-3× shorter than nonmusicians' (~200 ms), suggesting more refined multisensory integration and audiovisual binding. Collectively, findings indicate a more refined binding of auditory and visual cues in musically trained individuals. We conclude that experience-dependent plasticity of intensive musical experience extends beyond simple listening skills, improving multimodal processing and the integration of multiple sensory systems in a domain-general manner.

  15. Musicians have enhanced audiovisual multisensory binding: experience-dependent effects in the double-flash illusion.

    PubMed

    Bidelman, Gavin M

    2016-10-01

    Musical training is associated with behavioral and neurophysiological enhancements in auditory processing for both musical and nonmusical sounds (e.g., speech). Yet, whether the benefits of musicianship extend beyond enhancements to auditory-specific skills and impact multisensory (e.g., audiovisual) processing has yet to be fully validated. Here, we investigated multisensory integration of auditory and visual information in musicians and nonmusicians using a double-flash illusion, whereby the presentation of multiple auditory stimuli (beeps) concurrent with a single visual object (flash) induces an illusory perception of multiple flashes. We parametrically varied the onset asynchrony between auditory and visual events (leads and lags of ±300 ms) to quantify participants' "temporal window" of integration, i.e., stimuli in which auditory and visual cues were fused into a single percept. Results show that musically trained individuals were both faster and more accurate at processing concurrent audiovisual cues than their nonmusician peers; nonmusicians had a higher susceptibility for responding to audiovisual illusions and perceived double flashes over an extended range of onset asynchronies compared to trained musicians. Moreover, temporal window estimates indicated that musicians' windows (<100 ms) were ~2-3× shorter than nonmusicians' (~200 ms), suggesting more refined multisensory integration and audiovisual binding. Collectively, findings indicate a more refined binding of auditory and visual cues in musically trained individuals. We conclude that experience-dependent plasticity of intensive musical experience extends beyond simple listening skills, improving multimodal processing and the integration of multiple sensory systems in a domain-general manner. PMID:27334887

  16. Effect of temperature and duration of post-cure on in vitro wear and quantity of remaining double bonds of resins containing carboxylic anhydride.

    PubMed

    Peutzfeldt, A

    1995-08-01

    The present study determined the effect of post-cure temperature and duration on in vitro wear resistance and quantity of remaining double bonds of anhydride-containing resins. Temperatures were varied between 37 degrees C and 225 degrees C, and durations were varied between 0 and 24 h. The quantity of remaining double bonds could not be established for post-cure temperatures of 200 degrees C or more due to melting of the polymer. A temperature of approximately 120 degrees C had optimal effect on wear resistance. Quantity of remaining double bonds and wear were found to decrease with increasing duration of post-cure. Low quantities of remaining double bonds were generally associated with low in vitro wear.

  17. 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

    . This setup ensures full compatibility with the future deployment of the analyser within IAGOS. For the initial water calibration of the instrument, a calibration of a similar instrument performed at MPI-BGC Jena against a dew point mirror (Dewmet, Michell instruments Ltd., UK) in the range from 0.7 to 3.0% was transferred to all subsequently manufactured CRDS instruments by Picarro. During the campaign the analyzer was compared against a reference frost point hygrometer, which is also used for calibration of the reference instrument FISH. The dew point mirror calibration was within 0.7 % of the FISH calibrator, but showed an offset of 14.45 ppm, which is consistent with the H2O content of dry tank air and diffusion effects through the inlet line (FEP). Furthermore, a new independent calibration method, based on the dilution effect of water vapour on CO2, was tested. It showed a 9 % low bias compared to the dew point mirror calibration. Comparison of the in-flight data against the reference systems showed that the analyzer is reliable and has a good long-term stability. Flight data from the DENCHAR campaign suggest a conservative precision estimate for measurements made at 0.4 Hz of 4 ppm for H2O < 100 ppm, and 4 % (relative) for H2O > 100 ppm. Accuracy at mixing ratios below 50 ppm was difficult to assess, as the reference instruments suffered from lack of stability. We present the results of the campaign flights and comparison with the reference instruments. The different calibration methods will be discussed.

  18. Fenoverine: a two-step, double-blind and open clinical assessments of its smooth muscle synchronizing effects.

    PubMed

    Bader, F

    1986-01-01

    A clinical trial on fenoverine was performed in two parts, one double-blind and one open. In the double-blind segment, 69 patients with chronic gastro-intestinal spasmodic conditions were allocated, according to a pre-set randomization table, to receive orally 3 daily doses of fenoverine (100 mg; 35 patients), trimebutine (150 mg; 14 patients) or placebo (20 patients) during an average of 8 days. In the open assay, 60 similar patients were treated during an average of 10 days with 100 mg fenoverine, orally, 3-times daily. Clinical efficacy was evaluated on the grounds of complete or almost complete remission of all symptoms and signs associated with the spasmodic condition. In the double-blind segment, 66% of patients given fenoverine experienced remission, a significantly higher proportion than those who had placebo (40%). The results with trimebutine (71%) could not be statistically differentiated from those of either fenoverine or placebo. In the open segment, 72% of patients experienced remission with fenoverine, thus showing an overall effectiveness in 70% of the total 95 patients who had such treatment. In neither study could a significant influence of spasm localization be shown on the clinical efficacy of fenoverine. Fenoverine also exerted an unexpected, though clinically interesting, anti-emetic action: of the 14 patients reporting vomiting on entry, 12 (86%) responded positively to fenoverine, whereas none responded out of the 3 who had placebo. Possible side-reactions were limited with fenoverine: there were only 17 (18%) complaints, mainly dry mouth, of which 6 were very mild.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3515369

  19. Effects of doubling the portion size of fruit and vegetable side dishes on children's intake at a meal.

    PubMed

    Kral, Tanja V E; Kabay, April C; Roe, Liane S; Rolls, Barbara J

    2010-03-01

    Increasing the portion size of energy-dense entrées has been shown to increase children's energy intake during a meal. It remains to be investigated whether serving larger portions to children can be used to promote intake of more healthful foods, such as fruits and vegetables (F&V). The aim of the present study was to examine the effects of increasing the portion size of F&V side dishes on children's intake. Forty-three children (22 boys, 21 girls), aged 5-6 years, were served dinner once a week for 2 weeks. Each dinner consisted of pasta with tomato sauce, three F&V side dishes (broccoli, carrots, and applesauce), and milk. The portion size of the F&V was doubled between experimental conditions whereas the size of the pasta remained constant. Doubling the portion size of the side dishes resulted in a 43% increase in children's intake of the fruit side dish (P = 0.001), but did not affect children's intake of the two vegetable side dishes (P > 0.60). Further, when the portion size of F&V side dishes was doubled, children ate significantly less of the pasta (P = 0.04). The difference in meal energy intake between portion size conditions (19.5 +/- 16.3 kcal) was not significant (P = 0.24). Although more studies are needed to understand whether increases in portion size can influence vegetable intake, children did eat more in response to a large quantity of a preferred low energy-dense fruit side dish at meals. Thus variations in portion size can be used strategically to help children achieve the recommended intake of fruits.

  20. Model studies of volatile diesel exhaust particle formation: are organic vapours involved in nucleation and growth?

    NASA Astrophysics Data System (ADS)

    Pirjola, L.; Karl, M.; Rönkkö, T.; Arnold, F.

    2015-09-01

    A high concentration of volatile nucleation mode particles (NUP) formed in the atmosphere when the exhaust cools and dilutes has hazardous health effects and it impairs the visibility in urban areas. Nucleation mechanisms in diesel exhaust are only poorly understood. We performed model studies using two sectional aerosol dynamics process models AEROFOR and MAFOR on the formation of particles in the exhaust of a diesel engine, equipped with an oxidative after-treatment system and running with low fuel sulfur content (FSC) fuel, under laboratory sampling conditions where the dilution system mimics real-world conditions. Different nucleation mechanisms were tested. Based on the measured gaseous sulfuric acid (GSA) and non-volatile core and soot particle number concentrations of the raw exhaust, the model simulations showed that the best agreement between model predictions and measurements in terms of particle number size distribution was obtained by barrier-free heteromolecular homogeneous nucleation between the GSA and a semi-volatile organic vapour combined with the homogeneous nucleation of GSA alone. Major growth of the particles was predicted to occur due to the similar organic vapour at concentrations of (1-2) × 1012 cm-3. The pre-existing core and soot mode concentrations had an opposite trend on the NUP formation, and the maximum NUP formation was predicted if a diesel particle filter (DPF) was used. On the other hand, the model predicted that the NUP formation ceased if the GSA concentration in the raw exhaust was less than 1010 cm-3, which was the case when biofuel was used.

  1. Experimental investigation of vapor shielding effects induced by ELM-like pulsed plasma loads using the double plasma gun device

    NASA Astrophysics Data System (ADS)

    Sakuma, I.; Kikuchi, Y.; Kitagawa, Y.; Asai, Y.; Onishi, K.; Fukumoto, N.; Nagata, M.

    2015-08-01

    We have developed a unique experimental device of so-called double plasma gun, which consists of two magnetized coaxial plasma gun (MCPG) devices, in order to clarify effects of vapor shielding on material erosion due to transient events in magnetically confined fusion devices. Two ELM-like pulsed plasmas produced by the two MCPG devices were injected into a target chamber with a variable time difference. For generating ablated plasmas in front of a target material, an aluminum foil sample in the target chamber was exposed to a pulsed plasma produced by the 1st MCPG device. The 2nd pulsed plasma was produced with a time delay of 70 μs. It was found that a surface absorbed energy measured by a calorimeter was reduced to ∼66% of that without the Al foil sample. Thus, the reduction of the incoming plasma energy by the vapor shielding effect was successfully demonstrated in the present experiment.

  2. Intense laser effects on the optical properties of asymmetric GaAs double quantum dots under applied electric field

    NASA Astrophysics Data System (ADS)

    Bejan, Doina; Niculescu, Ecaterina Cornelia

    2016-06-01

    We investigated the combined effects of a non-resonant intense laser field and a static electric field on the electronic structure and the nonlinear optical properties (absorption, optical rectification) of a GaAs asymmetric double quantum dot under a strong probe field excitation. The calculations were performed within the compact density-matrix formalism under steady state conditions using the effective mass approximation. Our results show that: (i) the electronic structure and optical properties are sensitive to the dressed potential; (ii) under applied electric fields, an increase of the laser intensity induces a redshift of the optical absorption and rectification spectra; (iii) the augment of the electric field strength leads to a blueshift of the spectra; (iv) for high electric fields the optical spectra show a shoulder-like feature, related with the occurrence of an anti-crossing between the two first excited levels.

  3. EFFECT OF A DENTIFRICE CONTAINING ALOE VERA ON PLAQUE AND GINGIVITIS CONTROL. A DOUBLE-BLIND CLINICAL STUDY IN HUMANS

    PubMed Central

    de Oliveira, Sílvia Morgana Araújo; Torres, Ticiana Carneiro; Pereira, Sérgio Luís da Silva; Mota, Olívia Morais de Lima; Carlos, Márlio Ximenes

    2008-01-01

    The effect of Aloe vera on the reduction of plaque and gingivitis was evaluated in a randomized, parallel and double-blind clinical trial. Subjects were randomly allocated to the test group (n=15) – dentifrice containing Aloe vera - or the control group (n=15) – fluoridated dentifrice. Plaque index (PI) and gingival bleeding index (GBI) were assessed at days 0 and 30. Subjects were asked to brush their teeth with the control or test dentifrice, three times a day, during a 30-day period. There was a significant reduction on plaque and gingivitis in both groups, but no statistically significant difference was observed among them (p>0.01). The dentifrice containing Aloe vera did not show any additional effect on plaque and gingivitis control compared to the fluoridated dentifrice. PMID:19089263

  4. Kirk effect mechanism in type-II InP /GaAsSb double heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Tao, N. G.; Bolognesi, C. R.

    2007-09-01

    The Kirk effect mechanism is studied in type-II InP /GaAsSb/InP NpN double heterojunction bipolar transistors (DHBTs) both experimentally and through two-dimensional hydrodynamic numerical simulations. We show that the large valence band discontinuity ΔEV at the GaAsSb-InP base/collector heterojunction does not allow hole injection into the InP collector as is the case in homojunction collectors. Instead, a blocking barrier is electrostatically induced in the base layer at high collector current densities: this barrier increases base recombination and decreases the current gain. We show that tunneling transport must be considered at the base/collector heterojunction and that the induced barrier depends on the base layer doping level—effectively, InP /GaAsSb DHBTs display high-current limitations that are also controlled to some extent by the base doping level.

  5. Two-photon double-ionization of the H2 molecule: effects of pulse duration

    NASA Astrophysics Data System (ADS)

    Guan, Xiaoxu; Bartschat, Klaus; Koesterke, Lars; Schneider, Barry

    2013-05-01

    In previous work, we solved the time-dependent Schrödinger equation to calculate the two-photon double ionization of the hydrogen molecule induced by non-sequential absorption of photons with a central energy of 30 eV in a short laser pulse lasting for about 1.6 femtoseconds. At the equilibrium internuclear separation, however, several doubly excited 1Σg , u states lie about 30 eV above the ground X1Σg state. There is significant disagreement among various results published to date on this problem already for the angle-integrated cross section, and hence for the angular distribution as well. In the present work we address and clarify the fundamental role of those doubly excited states, which are accessible through photon absorption, on the two-photon breakup process. This can only be achieved by allowing for much longer laser pulses. Work supported by the NSF under PHY-1068140 and the XSEDE allocation PHY-090031.

  6. Boosted output performance of triboelectric nanogenerator via electric double layer effect

    PubMed Central

    Chun, Jinsung; Ye, Byeong Uk; Lee, Jae Won; Choi, Dukhyun; Kang, Chong-Yun; Kim, Sang-Woo; Wang, Zhong Lin; Baik, Jeong Min

    2016-01-01

    For existing triboelectric nanogenerators (TENGs), it is important to explore unique methods to further enhance the output power under realistic environments to speed up their commercialization. We report here a practical TENG composed of three layers, in which the key layer, an electric double layer, is inserted between a top layer, made of Al/polydimethylsiloxane, and a bottom layer, made of Al. The efficient charge separation in the middle layer, based on Volta's electrophorus, results from sequential contact configuration of the TENG and direct electrical connection of the middle layer to the earth. A sustainable and enhanced output performance of 1.22 mA and 46.8 mW cm−2 under low frequency of 3 Hz is produced, giving over 16-fold enhancement in output power and corresponding to energy conversion efficiency of 22.4%. Finally, a portable power-supplying system, which provides enough d.c. power for charging a smart watch or phone battery, is also successfully developed. PMID:27703165

  7. Environmentally friendly power generator based on moving liquid dielectric and double layer effect

    PubMed Central

    Huynh, D. H.; Nguyen, T. C.; Nguyen, P. D.; Abeyrathne, C. D.; Hossain, Md. S.; Evans, R.; Skafidas, E.

    2016-01-01

    An electrostatic power generator converts mechanical energy to electrical energy by utilising the principle of variable capacitance. This change in capacitance is usually achieved by varying the gap or overlap between two parallel metallic plates. This paper proposes a novel electrostatic micro power generator where the change in capacitance is achieved by the movement of an aqueous solution of NaCl. A significant change in capacitance is achieved due to the higher than air dielectric constant of water and the Helmholtz double layer capacitor formed by ion separation at the electrode interfaces. The proposed device has significant advantages over traditional electrostatic devices which include low bias voltage and low mechanical frequency of operation. This is critical if the proposed device is to have utility in harvesting power from the environment. A figure of merit exceeding 10000(108μW)/(mm2HzV2) which is two orders of magnitude greater than previous devices, is demonstrated for a prototype operating at a bias voltage of 1.2 V and a droplet frequency of 6 Hz. Concepts are presented for large scale power harvesting. PMID:27255577

  8. Delocalization effects, entanglement entropy and spectral collapse of boson mixtures in a double well

    NASA Astrophysics Data System (ADS)

    Lingua, F.; Mazzarella, G.; Penna, V.

    2016-10-01

    We investigate the ground-state properties of a two-species condensate of interacting bosons in a double-well potential. Each atomic species is described by a two-space-mode Bose–Hubbard model. The coupling of the two species is controlled by the interspecies interaction W. To analyze the ground state when W is varied in both the repulsive (W\\gt 0) and the attractive (W\\lt 0) regime, we apply two different approaches. First we solve the problem numerically (i) to obtain an exact description of the ground-state structure and (ii) to characterize its correlation properties by studying (the appropriate extensions to the present case of) the quantum Fisher information, the coherence visibility and the entanglement entropy as functions of W. Then we approach analytically the description of the low-energy scenario by means of the Bogoliubov scheme. In this framework the ground-state transition from delocalized to localized species (with space separation for W\\gt 0, and mixing for W\\lt 0) is well reproduced. These predictions are qualitatively corroborated by our numerical results. We show that such a transition features a spectral collapse reflecting the dramatic change of the dynamical algebra of the four-mode model Hamiltonian.

  9. Environmentally friendly power generator based on moving liquid dielectric and double layer effect.

    PubMed

    Huynh, D H; Nguyen, T C; Nguyen, P D; Abeyrathne, C D; Hossain, Md S; Evans, R; Skafidas, E

    2016-06-03

    An electrostatic power generator converts mechanical energy to electrical energy by utilising the principle of variable capacitance. This change in capacitance is usually achieved by varying the gap or overlap between two parallel metallic plates. This paper proposes a novel electrostatic micro power generator where the change in capacitance is achieved by the movement of an aqueous solution of NaCl. A significant change in capacitance is achieved due to the higher than air dielectric constant of water and the Helmholtz double layer capacitor formed by ion separation at the electrode interfaces. The proposed device has significant advantages over traditional electrostatic devices which include low bias voltage and low mechanical frequency of operation. This is critical if the proposed device is to have utility in harvesting power from the environment. A figure of merit exceeding 10000(10(8)μW)/(mm(2)HzV(2)) which is two orders of magnitude greater than previous devices, is demonstrated for a prototype operating at a bias voltage of 1.2 V and a droplet frequency of 6 Hz. Concepts are presented for large scale power harvesting.

  10. Effect of the manipulation of the duodenal papilla during double balloon enteroscopy

    PubMed Central

    Latorre, Rafael; López-Albors, Octavio; Soria, Federico; Candanosa, Eugenia; Pérez-Cuadrado, Enrique

    2016-01-01

    AIM: To determine the hypothesis that inflating the balloons in the duodenal papilla determines changes in the biochemical markers of pancreatitis. METHODS: Four groups of pigs were used: Group papilla (GP), the overtube’s balloon was inflated in the area of the papilla; GP + double balloon enteroscopy (GP + DBE), the overtube’s balloon was kept inflated in the area of the papilla for 20 min before a DBE; Group DBE (GDBE), DBE was carried out after insuring the balloon’s inflation far from the pancreatic papilla; and Group control (GC). Serum concentrations of amylase, lipase and C-reactive protein (CRP) were evaluated. Pancreases were processed for histopathology examination. RESULTS: Main changes occurred 24 h after the procedure compared with baseline levels. Amylase levels increased significantly in GP (59.2% higher) and were moderately higher in groups GP + DBE and GDBE (22.7% and 20%, respectively). Lipase increased in GP and GP + DBE, whereas it hardly changed in GDBE and in GC. CRP increased significantly in GP, GP + DBE and GDBE, while no changes were reported for GC. No statistically significant difference between groups GP and GP + DBE was found for the histopathological findings, except for vacuolization and necrosis of the pancreatic parenchyma that was higher in GP than in GP + DBE. CONCLUSION: The manipulation of the duodenal papilla by the inflated overtube’s balloon during DBE causes pancreatic structural damage and increased biochemical markers associated with pancreatitis. PMID:27158201

  11. Interactions and thermoelectric effects in a parallel-coupled double quantum dot

    NASA Astrophysics Data System (ADS)

    Sierra, Miguel A.; Saiz-Bretín, M.; Domínguez-Adame, F.; Sánchez, David

    2016-06-01

    We investigate the nonequilibrium transport properties of a double quantum-dot system connected in parallel to two leads, including intradot electron-electron interaction. In the absence of interactions, the system supports a bound state in the continuum. This state is revealed as a Fano antiresonance in the transmission when the energy levels of the dots are detuned. Using the Keldysh nonequilibrium Green's-function formalism, we find that the occurrence of the Fano antiresonance survives in the presence of Coulomb repulsion. We give precise predictions for the experimental detection of bound states in the continuum. First, we calculate the differential conductance as a function of the applied voltage and the dot level detuning and find that crossing points in the diamond structure are revealed as minima due to the transmission antiresonances. Second, we determine the thermoelectric current in response to an applied temperature bias. In the linear regime, quantum interference gives rise to sharp peaks in the thermoelectric conductance. Remarkably, we find interaction-induced strong current nonlinearities for large thermal gradients that may lead to several nontrivial zeros in the thermocurrent. The latter property is especially attractive for thermoelectric applications.

  12. Boosted output performance of triboelectric nanogenerator via electric double layer effect

    NASA Astrophysics Data System (ADS)

    Chun, Jinsung; Ye, Byeong Uk; Lee, Jae Won; Choi, Dukhyun; Kang, Chong-Yun; Kim, Sang-Woo; Wang, Zhong Lin; Baik, Jeong Min

    2016-10-01

    For existing triboelectric nanogenerators (TENGs), it is important to explore unique methods to further enhance the output power under realistic environments to speed up their commercialization. We report here a practical TENG composed of three layers, in which the key layer, an electric double layer, is inserted between a top layer, made of Al/polydimethylsiloxane, and a bottom layer, made of Al. The efficient charge separation in the middle layer, based on Volta's electrophorus, results from sequential contact configuration of the TENG and direct electrical connection of the middle layer to the earth. A sustainable and enhanced output performance of 1.22 mA and 46.8 mW cm-2 under low frequency of 3 Hz is produced, giving over 16-fold enhancement in output power and corresponding to energy conversion efficiency of 22.4%. Finally, a portable power-supplying system, which provides enough d.c. power for charging a smart watch or phone battery, is also successfully developed.

  13. Environmentally friendly power generator based on moving liquid dielectric and double layer effect

    NASA Astrophysics Data System (ADS)

    Huynh, D. H.; Nguyen, T. C.; Nguyen, P. D.; Abeyrathne, C. D.; Hossain, Md. S.; Evans, R.; Skafidas, E.

    2016-06-01

    An electrostatic power generator converts mechanical energy to electrical energy by utilising the principle of variable capacitance. This change in capacitance is usually achieved by varying the gap or overlap between two parallel metallic plates. This paper proposes a novel electrostatic micro power generator where the change in capacitance is achieved by the movement of an aqueous solution of NaCl. A significant change in capacitance is achieved due to the higher than air dielectric constant of water and the Helmholtz double layer capacitor formed by ion separation at the electrode interfaces. The proposed device has significant advantages over traditional electrostatic devices which include low bias voltage and low mechanical frequency of operation. This is critical if the proposed device is to have utility in harvesting power from the environment. A figure of merit exceeding 10000(108μW)/(mm2HzV2) which is two orders of magnitude greater than previous devices, is demonstrated for a prototype operating at a bias voltage of 1.2 V and a droplet frequency of 6 Hz. Concepts are presented for large scale power harvesting.

  14. Experimental Investigation of the Effect of M-Band Preheating in Indirectly-Driven Double-Shell Implosions

    SciTech Connect

    Robey, H F; Amendt, P A; Park, H-S; Landen, O L; Watt, R G; Varnum, W S

    2003-08-22

    Experimental results are presented from several series of experiments studying the effect of 2-4 keV M-shell radiation on the implosion of double-shell capsules on the Omega Laser at the Laboratory for Laser Energetics. In the First series of experiments, precision machined double-shell capsules implosions are performed. A discrepancy is observed between the experimentally measured M-band fraction and the simulated value. The application of a time-dependent multiplier to the simulated M-band level results in a decrease in predicted yield of 35% and a corresponding increase in the YoC to 20-35%. In order to further investigate this discrepancy, a series of ''M-Band driven'' targets has been designed. An oversized outer shell is used to preferentially allow the M-band radiation to drive the implosion of a CH-tamped glass inner shell. The inner shell radius-time history is measured and is shown to be consistent with the simulations using the time-dependent M-band multipliers. The spatial distribution of this M-band source is also varied using hohlraums of different length and adjusting the laser pointing accordingly. The resulting asymmetry of the inner shell implosion is diagnosed both by x-ray backlighting prior to shell collision and by core emission.

  15. Effect of a mangosteen dietary supplement on human immune function: a randomized, double-blind, placebo-controlled trial.

    PubMed

    Tang, Yu-Ping; Li, Peng-Gao; Kondo, Miwako; Ji, Hong-Ping; Kou, Yan; Ou, Boxin

    2009-08-01

    The effect of a mangosteen product containing multivitamins and essential minerals was tested on immune function and well-being in healthy adults. A randomized, double blinded, placebo-controlled study was conducted in 59 healthy human subjects (40-60 years old). Changes from baseline immune function were measured after a 30-day consumption of the mangosteen product and the placebo. The subjects' self-appraisal of their health status was also surveyed. A xanthone-rich mangosteen product intake increased mean values for peripheral T-helper cell frequency (P = .020) and reduced the serum C-reactive protein concentration (P = .014). Increases in peripheral CD4/CD8 double-positive (DP) T-cell frequency and serum complement C3, C4, and interleukin (IL)-1alpha concentrations were significantly higher in the experimental group than in the placebo group (DP, P = .038; C3, P = .017; C4, P = .031; IL-1alpha, P = .006). At the end of study, serum IL-1alpha and IL-1beta concentrations in the study group were significantly higher than that in the placebo group (IL-1alpha, P = .033; IL-1beta, P = .04). Furthermore, more participants in the experimental group reported greatly improved overall health status compared with participants receiving placebo (P = .001). The results indicated that the intake of an antioxidant-rich product significantly enhanced immune responses and improved the subject's self-appraisal on his or her overall health status.

  16. Effective Operation for an Adsorptive Desiccant Cooling Process using a Double-Stage Regeneration of Honeycomb Rotary Dehumidifier

    NASA Astrophysics Data System (ADS)

    Kodama, Akio; Ando, Kouke; Hirose, Tsutomu; Goto, Motonobu; Tuziguchi, Takuya; Okano, Hiroshi

    A double-stage regeneration concept has been applied to a rotary dehumidifier to achieve a high efficient desiccant cooling process. In this concept, regeneration zone of the dehumidifier was divided into two zones. One was pre-regeneration zone where the desiccant rotor was regenerated by warm air heated at the sensible heat exchanger, and the other was heating regeneration zone where the rotor was further regenerated by hot air heated up to the controlled temperature at a heating system. In this paper, the influence of the area ratio of these two zones on the dehumidifying/cooling performance and energy efficiency of this desiccant system were mainly discussed at several levels of the regeneration temperature, supply air velocity and inlet air humidity. Experimental results indicated that the area ratio of the heating regeneration zone should be optimized to produce a sufficient dehumidifying/cooling performance with high energy efficiency, considering humidity requested in supply air. It was also found that the amount of energy input was rather decreased than the decrease of the cooling performance as the area ratio of the heating regeneration zone decreased, and this tendency was more remarkable at higher regeneration temperature. Finally, the double-stage regeneration was confirmed to be an effective operating method for the desiccant cooling process equipped with a otary dehumidifier.

  17. Effects of central metal on electronic structure, magnetic properties, infrared and Raman spectra of double-decker phthalocyanine

    NASA Astrophysics Data System (ADS)

    Suzuki, Atsushi; Oku, Takeo

    2016-09-01

    The effects of the central metal in double-decker metal phthalocyanine on the electronic structure, magnetic properties, and infrared and Raman spectra of the complex were investigated. Electron density distributions were delocalized on the phthalocyanine rings. The narrow energy gap and infrared peaks observed in the ultra-violet-visible-near infrared spectra of the systems were attributed to phthalocyanine ring-ring interactions the between overlapping π-orbitals on each ring. The chemical shift behavior of the phthalocyanine rings was separated by the deformation of their structure owing to nuclear magnetic interaction of the nuclear quadrupole interaction as determined by the electronic field gradient and asymmetric parameters. The magnetic parameters of principle g-tensors were dependent on the perturbation of the crystal field by the hybridization of the d-spin in the central metal conjugated with nitrogen ligands. In the case of the vanadyl system, the IR vibration modes were shifted by the soft vibration mode for resolving the symmetrical structure. Inactive Raman vibration modes arose from no-polarization on the phthalocyanine rings. Double-decker metal phthalocyanines have great advantages for the control of the magnetic mechanism for quantum spin entanglement in the relaxation process.

  18. [Nitrogen absorption and allocation in cotton plant under effects of double-cropping wheat and cotton root mass].

    PubMed

    Wang, Ying; Zhou, Zhiguo; Chen, Binglin; Meng, Yali; Shu, Hongmei

    2006-12-01

    By the methods of 15N-foliar feeding and 15N dilution, a pot experiment of double-cropping wheat and cotton was conducted to study the nitrogen absorption and allocation in cotton plant under effects of wheat and cotton root mass. Three treatments were installed, i.e., no separation of wheat and cotton roots (treatment I), separation with nylon net (treatment II), and separation with plastic film (treatment III). The results showed that both the competition of 15N absorption between wheat and cotton root, and the translocation of absorbed 15N from wheat root to cotton were existed in the wheat-cotton double-cropping system. The absorbed 15N by cotton root was mostly allocated in aboveground part, and less in root. The aboveground part of cotton had the highest N utilization rate (NUR) in treatment I and the lowest one in treatment III, but the Ndff was lower in treatment I than in treatments II and III. At the early flowering stage of cotton when wheat was harvested and its straw was amended in situ, the absorbed nitrogen by cotton was mainly from the applied 15N, but not from the amended wheat straw. The allocation of absorbed 15N in different organs of cotton was quite different, being much higher in reproductive organs than in other organs. The biomass of cotton plant was also higher in treatment I than in treatments II and III.

  19. The effectiveness of intramuscular biperiden in acute akathisia: a double-blind, randomized, placebo-controlled study.

    PubMed

    Baskak, Bora; Atbasoglu, E Cem; Ozguven, Halise Devrimci; Saka, Meram Can; Gogus, Ali Kemal

    2007-06-01

    Neuroleptic-induced acute akathisia (NIA) is a distressing condition and an important clinical problem because it is associated with treatment noncompliance and suicidal or impulsive behavior. Anticholinergics are among the treatment options; however, a review of the literature fails to identify a double-blind, randomized, placebo-controlled study of these medications in NIA. In a randomized, double-blind, placebo-controlled design, we studied the effectiveness of intramuscular biperiden (n = 15) or isotonic saline (n = 15) in the treatment of NIA diagnosed with the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria. Injections were repeated up to 3 times unless akathisia was completely treated (scored 0 for global akathisia with the Barnes Akathisia Rating Scale). Patients were assessed for akathisia, other movement disorders, and psychiatric symptoms at baseline and 3 times after the first injection at 2-hour intervals. Response was defined as at least a 2-point decline in the global akathisia score. The numbers of responders in the 2 groups were not significantly different (7 and 5 in the biperiden and placebo groups, respectively). The courses of individual items on the Barnes Akathisia Rating Scale were also similar. Our results suggest that intramuscular biperiden should not be considered as a first-line treatment of NIA.

  20. Effects of Proprioceptive Neuromuscular Facilitation Stretching and Kinesiology Taping on Pelvic Compensation During Double-Knee Extension

    PubMed Central

    Lee, Seung-Woong; Lee, Jung-Hoon

    2015-01-01

    Shortened hamstrings are likely to restrict the anterior pelvic tilt and induce a slumped posture due to the posterior pelvic tilt. This study was conducted to compare the effects of proprioceptive neuromuscular facilitation (PNF) stretching and modified anterior pelvic tilt taping (APTT) on hamstring shortness-associated pelvic compensation while executing seated double-knee extension. Male college students (28 healthy young adults; mean age: 21.4 ± 2.1 years) with hamstring shortness were recruited as study subjects and randomly assigned to either the PNF stretching group (control group) or the APTT group (experimental group). In all the subjects, changes in the movement distance of the centre of gluteal pressure (COGP) as well as rectus abdominis (RA) and semitendinosus (SEM) muscle activities were measured during seated double-knee extension while the respective intervention method was applied. Both groups showed significant decreases in COGP distance and RA muscle activity compared with their respective baseline values (p < 0.05), however, no significant changes were observed in SEM muscle activity. We can infer that not only a direct intervention on the hamstring, such as PNF stretching, but also a modified APTT-mediated pelvic intervention may be used as a method for reducing pelvic compensation induced by hamstring shortness. PMID:26839606

  1. Effects of Proprioceptive Neuromuscular Facilitation Stretching and Kinesiology Taping on Pelvic Compensation During Double-Knee Extension.

    PubMed

    Lee, Seung-Woong; Lee, Jung-Hoon

    2015-12-22

    Shortened hamstrings are likely to restrict the anterior pelvic tilt and induce a slumped posture due to the posterior pelvic tilt. This study was conducted to compare the effects of proprioceptive neuromuscular facilitation (PNF) stretching and modified anterior pelvic tilt taping (APTT) on hamstring shortness-associated pelvic compensation while executing seated double-knee extension. Male college students (28 healthy young adults; mean age: 21.4 ± 2.1 years) with hamstring shortness were recruited as study subjects and randomly assigned to either the PNF stretching group (control group) or the APTT group (experimental group). In all the subjects, changes in the movement distance of the centre of gluteal pressure (COGP) as well as rectus abdominis (RA) and semitendinosus (SEM) muscle activities were measured during seated double-knee extension while the respective intervention method was applied. Both groups showed significant decreases in COGP distance and RA muscle activity compared with their respective baseline values (p < 0.05), however, no significant changes were observed in SEM muscle activity. We can infer that not only a direct intervention on the hamstring, such as PNF stretching, but also a modified APTT-mediated pelvic intervention may be used as a method for reducing pelvic compensation induced by hamstring shortness.

  2. 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.

  3. Deuterium excess in the atmospheric water vapour of a Mediterranean coastal wetland: regional vs. local signatures

    NASA Astrophysics Data System (ADS)

    Delattre, H.; Vallet-Coulomb, C.; Sonzogni, C.

    2015-09-01

    Stable isotopes of water vapour represent a powerful tool for tracing atmospheric vapour origin and mixing processes. Laser spectrometry recently allowed high time-resolution measurements, but despite an increasing number of experimental studies, there is still a need for a better understanding of the isotopic signal variability at different time scales. We present results of in situ measurements of δ18O and δD during 36 consecutive days in summer 2011 in atmospheric vapour of a Mediterranean coastal wetland exposed to high evaporation (Camargue, Rhône River delta, France). The mean composition of atmospheric vapour (δv) is δ18O = -14.66 ‰ and δD = - 95.4 ‰, with data plotting clearly above the local meteoric water line on a δ18O-δD plot, and an average deuterium excess (d) of 21.9 ‰. Important diurnal d variations are observed, and an hourly time scale analysis is necessary to interpret the main processes involved in its variability. After having classified the data according to air mass back trajectories, we analyse the average daily cycles relating to the two main meteorological situations, i.e. air masses originating from North Atlantic Ocean and Mediterranean Sea. In both situations, we show that diurnal fluctuations are driven by (1) the influence of local evaporation, culminating during daytime, and leading to an increase in absolute water vapour concentration associated to a δv enrichment and d increase; (2) vertical air mass redistribution when the Planetary Boundary Layer collapses in the evening, leading to a d decrease, and (3) dew formation during the night, producing a δv depletion with d remaining stable. Using a two-component mixing model, we calculate the average composition of the locally evaporated vapour (δE). We find higher d(E) under North Atlantic air mass conditions, which is consistent with lower humidity conditions. We also suggest that δv measured when the PBL collapses is the most representative of a regional signal

  4. Novel Indium Arsenide double gate and gate all around nanowire MOSFETs for diminishing the exchange correlation effect: A quantum study

    NASA Astrophysics Data System (ADS)

    Orouji, Ali A.; Nejaty, Mohammad; Mohtasham, Alireza

    2014-09-01

    In this paper we present novel double gate (DG) metal oxide semiconductor field effect transistor (MOSFET) and gate all around (GAA) nanowire metal oxide semiconductor field effect transistor (NWT) with a diminished exchange-correlation (Ex-Corr) effect. The key idea in this work is to use Indium Arsenide (InAs) semiconductor instead of Si. We have evaluated and compared different parameters of DG-MOSFET and GAA-NWTs such as threshold voltage, sub-threshold slope, drain induced barrier lowering and ON and OFF state currents from quantum view. Quantum mechanical transport approach based on non-equilibrium green's function (NEGF) has been performed in the frame work of effective mass theory in consideration with Ex-Corr effect. This simulation method consists of three dimensional Poisson's equation in which a Schrodinger equation is first solved in each slice of the device to find Eigen energies and Eigen functions. Then, a transport equation of electrons moving in the sub-bands is solved. This fully quantum method treats such effects as source-to-drain tunneling, ballistic transport, and quantum confinement on equal footing. The results show that only a few lowest Eigen sub-bands are occupied and the upper sub-bands can be safely neglected. Also, the interaction between electrons and Ex-Corr effect is diminished in the proposed structure.

  5. Effects of somatotrophic axis (GH/GHR) double transgenesis on structural and molecular aspects of the zebrafish immune system.

    PubMed

    Batista, Carolina Reyes; Figueiredo, Marcio Azevedo; Almeida, Daniela Volcan; Romano, Luis Alberto; Marins, Luis Fernando

    2015-08-01

    The development of growth hormone (GH) transgenic fish has been shown to be a promising method to improve growth rates. However, the role of GH is not restricted only to processes involved in growth. Several others physiological processes, including immune function, are impaired due to GH imbalances. Given the importance of generating GH transgenic organisms for aquaculture purposes, it is necessary to develop strategies to reduce or compensate for the collateral effects of GH. We hypothesized that the generation of double transgenic fish that overexpress GH and growth hormone receptor (GHR) in the skeletal muscle could be a possible alternative to compensate for the deleterious effects of GH on the immune system. Specifically, we hypothesized that increased GHR amounts in the skeletal muscle would be able to reduce the level of circulating GH, attenuating the GH signaling on the immune cells while still increasing the growth rate. To test this hypothesis, we evaluated the size of the immune organs, T cell content in the thymus and head kidney, and expression of immune-related genes in double-transgenic fish. Contrary to our expectations, we found that the overexpression of GHR does not decrease the deleterious effect of GH excess on the size of the thymus and head kidney, and in the content of CD3(+) and CD4(+) cells in the thymus and head kidney. Unexpectedly, the control GHR transgenic group showed similar impairments in immune system parameters. These results indicate that GHR overexpression does not reverse the impairments caused by GH and, in addition, could reinforce the damage to the immune functions in GH transgenic zebrafish.

  6. Effect of Atmosphere on Collinear Double-Pulse Laser-Induced Breakdown Spectroscopy

    SciTech Connect

    Andrew J. Effenberger, Jr; Jill R. Scott

    2011-07-01

    Double pulse laser induced breakdown spectroscopy (DP-LIBS) has been shown to enhance LIBS spectra. Several researches have reported significant increases in signal-to-noise and or spectral intensity. In addition to DP-LIBS, atmospheric conditions can also increase spectra intensity. For example, He and Ar both increase LIBS intensity compared to air at one 1 atm. It was also found that as the pressure was decreased to 100 Torr, LIBS intensity increased in Ar and air for single pulse (SP) LIBS. In this study, a collinear DP-LIBS scheme is used along with manipulation of the atmospheric conditions. The DP-LIBS scheme consists of a 355 nm ablative pulse fired into a sample contained in a vacuum chamber. A second analytical 1064 nm pulse is then fired 100 ns to 10 {micro}s after and along the same path of the first pulse. Ar, He and air at pressures ranging from atmospheric pressure (630 Torr at elevation) to 10{sup -5} Torr are introduced during DP-LIBS and SP-LIBS experiments. For a brass sample, a significant increase in spectral intensity of Cu and Zn lines were observed in DP-LIBS under Ar compared to DP-LIBS in air. It was also found that Cu and Zn lines acquired with SP-LIBS in Ar are nearly as intense as DP-LIBS in air. Signal-to-noise for lines from various samples will be reported for both DP-LIBS and SP-LIBS in Ar, He, and air at pressures ranging from 630 Torr to 10{sup -5} Torr.

  7. Effect of atmosphere on collinear double-pulse laser-induced breakdown spectroscopy

    SciTech Connect

    Andrew J. Effenberger, Jr.; Jill R. Scott

    2010-09-01

    Double pulse laser induced breakdown spectroscopy (DP-LIBS) has been shown to enhance LIBS spectra. Several researches have reported significant increases in signal-to-noise and or spectral intensity [1-4]. In addition to DP-LIBS, atmospheric conditions can also increase spectra intensity. For example, Iida [5] found that He and Ar both increase LIBS intensity compared to air at one 1 atm. It was also found that as the pressure was decreased to 100 Torr, LIBS intensity increased in Ar and air for single pulse (SP) LIBS. In this study, a collinear DP-LIBS scheme is used along with manipulation of the atmospheric conditions. The DP-LIBS scheme consists of a 355 nm ablative pulse fired into a sample contained in a vacuum chamber. A second analytical 1064 nm pulse is then fired 100 ns to 10 µs after and along the same path of the first pulse. Ar, He and air at pressures ranging from atmospheric pressure (630 Torr at elevation) to 10-5 Torr are introduced during DP-LIBS and SP-LIBS experiments. For a brass sample, a significant increase in spectral intensity of Cu and Zn lines were observed in DP-LIBS under Ar compared to DP-LIBS in air (Figure 1). It was also found that Cu and Zn lines acquired with SP-LIBS in Ar are nearly as intense as DP-LIBS in air. Signal-to-noise for lines from various samples will be reported for both DP-LIBS and SP-LIBS in Ar, He, and air at pressures ranging from 630 Torr to 10-5 Torr.

  8. Ion specific effects on the stability of layered double hydroxide colloids.

    PubMed

    Pavlovic, Marko; Huber, Robin; Adok-Sipiczki, Monika; Nardin, Corinne; Szilagyi, Istvan

    2016-05-01

    Positively charged layered double hydroxide particles composed of Mg(2+) and Al(3+) layer-forming cations and NO3(-) charge compensating anions (MgAl-NO3-LDH) were synthesized and the colloidal stability of their aqueous suspensions was investigated in the presence of inorganic anions of different charges. The formation of the layered structure was confirmed by X-ray diffraction, while the charging and aggregation properties were explored by electrophoresis and light scattering. The monovalent anions adsorb on the oppositely charged surface to a different extent according to their hydration state leading to the Cl(-) > NO3(-) > SCN(-) > HCO3(-) order in surface charge densities. The ions on the right side of the series induce the aggregation of MgAl-NO3-LDH particles at lower concentrations, whereas in the presence of the left ones, the suspensions are stable even at higher salt levels. The adsorption of multivalent anions gave rise to charge neutralization and charge reversal at appropriate concentrations. For some di, tri and tetravalent ions, charge reversal resulted in restabilization of the suspensions in the intermediate salt concentration regime. Stable samples were also observed at low salt levels. Particle aggregation was fast near the charge neutralization point and at high concentrations. These results, which evidence the colloidal stability of MgAl-NO3-LDH in the presence of various anions, are of prime fundamental interest. These are also critical for applications to develop stable suspensions of primary particles for water purification processes, with the aim of the removal of similar anions by ion exchange. PMID:26997621

  9. Effect of double density caging during Space Shuttle transport of laboratory rats

    NASA Technical Reports Server (NTRS)

    Riskowski, G. L.; Gonyou, H. W.; Harrison, P. C.; Kelley, K. W.; Tumbleson, M. E.

    1993-01-01

    Male Sprague Dawley rats were housed in groups of four in polycarbonate cages at recommended density and thermal environmental conditions for 14 days prior to testing to ensure uniform acclimation to those conditions. Body weights averaged 286 +/- 7 g at the end of acclimation. Rat cages were assigned randomly to three treatments: (1) 4 rats/polycarbonate cage (877 sq cm, 20.3 cm high, 220 sq cm/rat), (2) 4 rats/mock AEM (MAEM) (620 sq cm, 155 sq cm/rat), and (3) 8 rats/MAEM (620 sq cm, 77.5 sq cm/rat). A comparison between the MAEM-DD and MAEM-SD treatments was done to determine if doubling rat density in AEM's stressed the rats. A comparison among MAEM treatments and the PC treatment was done to determine if any stress indications were due to the AEM. During this density challenge phase, all treatments were maintained at the same thermal environmental conditions (22.5 C and 50 percent RH) for 10 days. After the density challenge phase, half the rats from each group were sacrificed for body tissue and fluid analyses. The remaining half of the rats were housed at a density of 4 rats/cage in polycarbonate cages at normal thermal environmental conditions for an additional 10 days to determine if there were any differences in responses between treatments after a recovery period. The remaining rats were examined and sacrificed for body tissue and fluid analyses at the end of the recovery phase.

  10. Effect of Dy/Nd double layer on coercivity in Nd-Fe-B thin films

    SciTech Connect

    Koike, K. Umezawa, J.; Ishikawa, H.; Ogawa, D.; Mizuno, Y.; Kato, H.; Miyazaki, T.; Ando, Y.

    2014-05-07

    The Nd-Fe-B (t{sub NFB} = 30 nm)/[Dy (t{sub Dy} nm)/Nd (t{sub Nd} nm)] (t{sub Dy/Nd} = 20 nm) (thickness t{sub Dy} = 0–10 nm) thin films were deposited on Al{sub 2}O{sub 3}(0001) substrate and subsequently in-situ annealed at 470 °C. As-deposited Nd-Fe-B thin films with a highly perpendicular orientation of c-axis were deposited by introducing bcc-Mo(111) single crystal buffer layer. After post-annealing, the grain size of the Nd-Fe-B/Dy/Nd thin films with the t{sub Dy} = 10 nm and t{sub Nd} = 10 nm becomes large due to the Dy and the Nd atoms thermal diffusion, while DyFe{sub 2} and Dy oxide compounds are formed in Nd-Fe-B layers, which is confirmed by means of a combination of atomic force microscopy observation and X-ray diffraction measurement. The H{sub c} of Nd-Fe-B/Dy/Nd thin films with the t{sub Dy} = 10 nm and t{sub Nd} = 10 nm was approximately the same value of the Nd-Fe-B thin films without Dy/Nd double layer annealed at 470 °C. On the other hand, H{sub c} is enhanced to be about 22.1 kOe in the annealed Nd-Fe-B/Dy/Nd films with the t{sub Dy} = 0.8 nm and t{sub Nd} = 19.2 nm.

  11. 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.

  12. Effect of energy restriction and re-alimentation in Belgian Blue double-muscled beef cows on digestibility and metabolites.

    PubMed

    Fiems, L O; Vanacker, J M; De Boever, J L; van Caelenbergh, W; Aerts, J M; De Brabander, D L

    2007-02-01

    Four groups of five non-lactating and non-pregnant Belgian Blue double-muscled (BBDM) cows were used to investigate the effect of energy level (E) on digestion, and blood and urine metabolites. The energy levels of the groups, applied indoors during a 140-day restriction period, were 100%, 90%, 80% or 70% of their energy requirements (E100, E90, E80, E70) respectively. Afterwards, animals grazed on the same swards for 203 days (re-alimentation period). Balance trials were conducted at the end of the restriction period (BT1) and at the end of the re-alimentation period (BT2). Blood was sampled at the end of these trials. Diets consisted of maize silage and straw (80/20 on a dry matter basis) and a mineral-vitamin premix, fed at the appropriate E during BT1, or maize silage and a mineral-vitamin premix, fed at 125% of the maintenance requirements, during BT2. Significant increases of the digestibility coefficients were found during BT1 when E decreased, resulting in a better net energy capture of 7% for E70 compared with E100 (p < 0.05). Slightly, but non-significantly higher digestibility coefficients were observed for decreasing E during BT2. Plasma concentrations of glucose and creatinine did not differ between treatments during BT1, while differences were found for triacylglycerols and alpha-amino nitrogen. A tendency for a linear increase was observed for non-esterified fatty acids with decreasing E. Differences in blood metabolite concentrations disappeared in BT2. Urinary creatinine excretion was not affected by E, while body nitrogen loss increased linearly with energy restriction in BT1. No differences were found during BT2, suggesting that non-lactating and non-pregnant BBDM cows are able to adapt to a cyclic change of body weight and body reserves. These data show that restricted cows mobilized body fat as well as body protein. It is concluded that the qualitative aspects of metabolism during energy restriction are comparable in double-muscled cows with

  13. A carrier-based analytical theory for negative capacitance symmetric double-gate field effect transistors and its simulation verification

    NASA Astrophysics Data System (ADS)

    Jiang, Chunsheng; Liang, Renrong; Wang, Jing; Xu, Jun

    2015-09-01

    A carrier-based analytical drain current model for negative capacitance symmetric double-gate field effect transistors (NC-SDG FETs) is proposed by solving the differential equation of the carrier, the Pao-Sah current formulation, and the Landau-Khalatnikov equation. The carrier equation is derived from Poisson’s equation and the Boltzmann distribution law. According to the model, an amplified semiconductor surface potential and a steeper subthreshold slope could be obtained with suitable thicknesses of the ferroelectric film and insulator layer at room temperature. Results predicted by the analytical model agree well with those of the numerical simulation from a 2D simulator without any fitting parameters. The analytical model is valid for all operation regions and captures the transitions between them without any auxiliary variables or functions. This model can be used to explore the operating mechanisms of NC-SDG FETs and to optimize device performance.

  14. Double-slit interference effect in electron emission from H2+ exposed to x-ray radiation

    NASA Astrophysics Data System (ADS)

    Guan, Xiaoxu; Secor, Ethan B.; Bartschat, Klaus; Schneider, Barry I.

    2012-04-01

    We consider the photoionization of the hydrogen molecular ion exposed to x-ray radiation for photon energies up to 500 eV in the fixed-nuclei approximation. The temporal development of the system is described by a fully ab initio time-dependent grid-based approach in prolate spheroidal coordinates. At sufficently high photon energies, the angular distributions of the electron ejected from the two-center diatomic target resemble the classical double-slit-like interference pattern more closely when the molecular axis and the linear laser polarization direction are perpendicular to each other than in the parallel geometry. Both the preferable emission modes and the confinement effect (in the parallel geometry) of the photoelectron also map out in the time evolution of the wave packets. The validity of a simple plane-wave model is analyzed by comparing its predictions with those from our accurate ab initio calculations.

  15. Numerical modeling of HgCdTe solidification: effects of phase diagram double-diffusion convection and microgravity level

    NASA Astrophysics Data System (ADS)

    Bune, Andris V.; Gillies, Donald C.; Lehoczky, Sandor L.

    1997-07-01

    A numerical model of HgCdTe solidification was implemented using finite the element code FIDAP. Model verification was done using both experimental data and numerical test problems. The model was used to eluate possible effects of double- diffusion convection in molten material, and microgravity level on concentration distribution in the solidified HgCdTe. Particular attention was paid to incorporation of HgCdTe phase diagram. It was found, that below a critical microgravity amplitude, the maximum convective velocity in the melt appears virtually independent on the microgravity vector orientation. Good agreement between predicted interface shape and an interface obtained experimentally by quenching was achieved. The results of numerical modeling are presented in the form of video film.

  16. Curvature Effect on the Capacitance of Electric Double Layers at Ionic Liquid/Onion-Like Carbon Interfaces

    SciTech Connect

    Feng, Guang; Jiang, Deen; Cummings, Peter T

    2012-01-01

    Recent experiments have revealed that onion-like carbons (OLCs) offer high energy density and charging/discharging rates when used as the electrodes in supercapacitors. To understand the physical origin of this phenomenon, molecular dynamics simulations were performed for a room-temperature ionic liquid near idealized spherical OLCs with radii ranging from 0.356 to 1.223 nm. We find that the surface charge density increases almost linearly with the potential applied on electric double layers (EDLs) near OLCs. This leads to a nearly flat shape of the differential capacitance versus the potential, unlike the bell or camel shape observed on planar electrodes. Moreover, our simulations reveal that the capacitance of EDLs on OLCs increases with the curvature or as the OLC size decreases, in agreement with experimental observations. The curvature effect is explained by dominance of charge overscreening over a wide potential range and increased ion density per unit area of electrode surface as the OLC becomes smaller.

  17. Effects of reducing temperatures on the hydrogen storage capacity of double-walled carbon nanotubes with Pd loading.

    PubMed

    Sheng, Qu; Wu, Huimin; Wexler, David; Liu, Huakun

    2014-06-01

    The effects of different temperatures on the hydrogen sorption characteristics of double-walled carbon nanotubes (DWCNTs) with palladium loading have been investigated. When we use different temperatures, the particle sizes and specific surface areas of the samples are different, which affects the hydrogen storage capacity of the DWCNTs. In this work, the amount of hydrogen storage capacity was determined (by AMC Gas Reactor Controller) to be 1.70, 1.85, 2.00, and 1.93 wt% for pristine DWCNTS and for 2%Pd/DWCNTs-300 degrees C, 2%Pd/DWCNTs-400 degrees C, and 2%Pd/DWCNTs-500 degrees C, respectively. We found that the hydrogen storage capacity can be enhanced by loading with 2% Pd nanoparticles and selecting a suitable temperature. Furthermore, the sorption can be attributed to the chemical reaction between atomic hydrogen and the dangling bonds of the DWCNTs. PMID:24738450

  18. Effects of initial delamination on CIc and GIth values from glass/epoxy double cantilever beam tests

    NASA Technical Reports Server (NTRS)

    Martin, Roderick H.

    1988-01-01

    The effect of insert thickness and method of precracking on mode I interlaminar fracture toughness, GIc, and delamination fatigue threshold, GIth, values were determined for a glass/epoxy double cantilever beam specimen. The results of the static tests showed that precracking in tension would cause fiber bridging and thus may yield unconservative values of GIc and GIth. Precracking in shear yields suitable values of GIc but overly conservative values of GIth. For the glass/epoxy composite used, an insert thickness of 0.5 mil was most suitable for determining GIc and GIth values, although an insert thickness up to 3 mil was acceptable. Inserts thicker than 3 mil were not acceptable for determining GIc and GIth values.

  19. Effects of hydrogen adsorption on the properties of double wall BN and (BN)xCy nanotubes

    NASA Astrophysics Data System (ADS)

    Freitas, A.; Azevedo, S.; Kaschny, J. R.

    2016-01-01

    In the present contribution, we apply first-principles calculations, based on the density functional theory, to study the effects of hydrogen adsorption on the structural and electronic properties of boron nitride and hybrid carbon-boron nitride double wall nanotubes. The results demonstrate that the hydrogen decoration induces significant structural deformation and an appreciable reduction in the gap energy. When the number of hydrogen atoms introduced on the outer wall is increased, desorption of hydrogen pairs are observed. The calculations indicate that each adsorbed hydrogen atom induces a structural deformation with an energetic cost of about 68 meV/atom. It is also found that the introduction of hydrogen atoms can be applied as an efficient tool for tuning the electronic properties of such structures.

  20. Effects of molecular symmetry on the directions of nuclear flux densities during tunnelling in double well potentials

    NASA Astrophysics Data System (ADS)

    Grohmann, Thomas; Manz, Jörn; Schild, Axel

    2013-08-01

    Coherent tunnelling in molecular systems with cyclic and non-cyclic symmetric double well potentials may proceed with similar nuclear densities, but with entirely different flux densities. For sufficiently high potential barriers, the nuclear densities may even become indistinguishable, whereas the patterns of the flux densities at a given time remain pincer-motion type for the cyclic systems, but unidirectional for the non-cyclic one. This effect is traced back to symmetry breaking of the cyclic to the non-cyclic model. Accordingly, nuclear flux densities are much more sensitive to symmetry breaking than nuclear densities. For a proof of principle, the phenomenon is demonstrated by means of three one-dimensional models. The cyclic model I represents torsion in oriented B2Cl2F2, the non-cyclic model II is constructed from I by symmetry breaking and the non-cyclic model III represents tunnelling by inversion of oriented NH3.