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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. 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

  3. The effects of urbanization on water vapour pressure in a semi-arid climate

    NASA Astrophysics Data System (ADS)

    Çiçek, I.; Türkoğlu, N.

    2009-01-01

    This study evaluates data from Aksaray, a medium sized urban city, and Cihanbeyli, a small town in Turkey, in order to show the effects of urbanization on water vapour pressure. Data taken at 07:00, 14:00 and 21:00 h and daily means were analyzed to identify the daily changes in water vapour pressure and temperatures. In Aksaray, positive urban heat island values were observed in all months except during afternoon hours. At all observation times during winter, weak water vapour pressure differences were recorded. During summer, on the other hand, positive water vapour differences were seen during afternoon and evening hours. A more humid city at afternoon hours is not typical of other mid-latitude countries. This is thought to be mainly related to the semi-arid climatic conditions in the area. Water vapour differences were seen to have a decreasing trend except during afternoon hours. As for temperature differences, an increase was seen during morning and evening hours, while a decrease was seen during afternoon hours and in daily means. A new trend was observed to start after the 1980s in both sets of data, which coincides with rapid population growth in Aksaray. Negative correlations were seen between water vapour pressure and temperature differences. No increase in water vapour pressure due to urbanization was observed in Aksaray. The decreasing evapotranspiration and the urban geometry appear to be the most influential factors in determining the water vapour pressure in Aksaray.

  4. 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

  5. The dynamic effects of metal vapour in gas metal arc welding

    NASA Astrophysics Data System (ADS)

    Haidar, Jawad

    2010-04-01

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

  6. Thermal effect of endoscopic thermal vapour ablation on the lung surface in human ex vivo tissue

    PubMed Central

    Henne, Erik; Anderson, Joseph C.; Barry, Robert; Kesten, Steven

    2012-01-01

    Purpose: An investigation of the thermal effect and the potential for injury at the lung surface following thermal vapour ablation (InterVapor), an energy-based method of achieving endoscopic lung volume reduction. Methods: Heated water vapour was delivered to fifteen ex vivo human lungs using standard clinical procedure, and the thermal effect at the visceral pleura was monitored with an infrared camera. The time–temperature response was analysed mathematically to determine a cumulative injury quotient, which was compared to published thresholds. Results: The cumulative injury quotients for all 71 treatments of ex vivo tissue were found to be below the threshold for first degree burn and no other markers of tissue injury at the lung surface were observed. Conclusion: The safety profile for thermal vapour ablation is further supported by the demonstration that the thermal effect in a worst-case model is not expected to cause injury at the lung surface. PMID:22690896

  7. Production of intense beams of polarized negative hydrogen ions by double charge exchange in alkali vapour

    NASA Astrophysics Data System (ADS)

    Gruëbler, W.; Schmelzbach, P. A.

    1983-07-01

    The intensity of the polarized negative hydrogen ion beam of the ETHZ atomic beam polarized ion source has been substantially improved by a new double charge exchange device. Increasing the diameter of the charge exchange canal to 1.4 cm results in a beam output of the source of 6 μA of polarized negative hydrogen ions. Further improvements of the charge exchanger are proposed and discussed. With an updated design of the atomic beam apparatus, beams of 0.5 mA polarized negative hydrogen ions may be obtained from such a source.

  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. Species doubling and effective Lagrangians

    SciTech Connect

    Creutz, M.; Tytgat, M.

    1996-09-01

    Coupling gauge fields to the chiral currents from an effective Lagrangian for pseudoscalar mesons naturally gives rise to a species doubling phenomenon similar to that seen with fermionic fields in lattice gauge theory. 17 refs.

  10. Effect of process parameters on the chemical vapour synthesis of nanocrystalline titania

    NASA Astrophysics Data System (ADS)

    Md, Imteyaz Ahmad; Bhattacharya, S. S.

    2008-08-01

    In this investigation nanocrystalline titania powders were produced by the chemical vapour synthesis (CVS) route and characterized by standard techniques of XRD, HRTEM and BET. The effects of precursor/gas flow rates, hotwall temperature and system pressure on the particle size and distribution, as well as phase composition of the synthesized nanocrystalline titania powder, were studied. It was demonstrated that by suitably adjusting the process parameters during CVS it becomes possible to control the anatase crystallite size, specific surface area and the rutile content in the synthesized nanocrystalline titania powders.

  11. Nanosilane in medium-density fibreboard: effects of vapour chamber on fluid flow.

    PubMed

    Taghiyari, Hamid Reza

    2015-02-01

    Effects were studied of vapour chamber on specific gas permeability of nanosilane (NS)-treated medium-density fibreboards (MDFs). Size range of nanoparticles was 20-80 nm. NS was used at four consumption levels of 0, 50, 100 and 150 g/kg dry wood fibres. Density of all treatments was kept constant at 0.67 g/cm(3). Specimens were kept for 18 weeks in vapourised chamber; their specific gas permeability was measured every two weeks. Results showed that extreme moisture uptake because of the biological structure of wood fibres, as well as mold and fungi growth on the specimens from the tenth week, resulted in the breaking down of the urea-formaldehyde resin; they also weakened the water-repellant effect of NS; consequently, the permeability increased significantly. It can be concluded that NS makes MDF susceptible to molds and therefore NS-treated MDF panels are not recommended for moist climates in which boards are exposed to water vapours in the air for a long time, although NS-panels primarily showed higher impermeability to water. PMID:25650321

  12. Giant spin Hall effect in graphene grown by chemical vapour deposition

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  13. 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

  14. Chemical Vapour Deposition Graphene Radio-Frequency Field-Effect Transistors

    NASA Astrophysics Data System (ADS)

    Ma, Peng; Jin, Zhi; Guo, Jian-Nan; Pan, Hong-Liang; Liu, Xin-Yu; Ye, Tian-Chun; Wang, Hong; Wang, Guan-Zhong

    2012-05-01

    We report the dc and rf performance of graphene rf field-effect transistors, where the graphene films are grown on copper by using the chemical vapour deposition (CVD) method and transferred to SiO2/Si substrates. Composite materials, benzocyclobutene and atomic layer deposition Al2O3 are used as the gate dielectrics. The observation of n- and p-type transitions verifies the ambipolar characteristics in the graphene layers. While the intrinsic carrier mobility of CVD graphene is extracted to be 1200 cm2/V·s, the parasitic series resistances are demonstrated to have a serious impact on device performance. With a gate length of 1 μm and an extrinsic transconductance of 72 mS/mm, a cutoff frequency of 6.6 GHz and a maximum oscillation frequency of 8.8 GHz are measured for the transistors, illustrating the potential of the CVD graphene for rf applications.

  15. Concentration effects on laser-based δ18 O and δ2 H measurements and implications for the calibration of vapour measurements with liquid standards.

    PubMed

    Schmidt, Markus; Maseyk, Kadmiel; Lett, Céline; Biron, Philippe; Richard, Patricia; Bariac, Thierry; Seibt, Ulli

    2010-12-30

    Recently available isotope ratio infrared spectroscopy can directly measure the isotopic composition of atmospheric water vapour (δ(18) O, δ(2) H), overcoming one of the main limitations of isotope ratio mass spectrometry (IRMS) methods. Calibrating these gas-phase instruments requires the vapourisation of liquid standards since primary standards in principle are liquids. Here we test the viability of calibrating a wavelength-scanned cavity ring-down spectroscopy (CRDS) instrument with vapourised liquid standards. We also quantify the dependency of the measured isotope values on the water concentration for a range of isotopic compositions. In both liquid and vapour samples, we found an increase in δ(18) O and δ(2) H with water vapour concentration. For δ(18) O, the slope of this increase was similar for liquid and vapour, with a slight positive relationship with sample δ-value. For δ(2) H, we found diverging patterns for liquid and vapour samples, with no dependence on δ-value for vapour, but a decreasing slope for liquid samples. We also quantified tubing memory effects to step changes in isotopic composition, avoiding concurrent changes in the water vapour concentration. Dekabon tubing exhibited much stronger, concentration-dependent, memory effects for δ(2) H than stainless steel or perfluoroalkoxy (PFA) tubing. Direct vapour measurements with CRDS in a controlled experimental chamber agreed well with results obtained from vapour simultaneously collected in cold traps analysed by CRDS and IRMS. We conclude that vapour measurements can be calibrated reliably with liquid standards. We demonstrate how to take the concentration dependencies of the δ-values into account. Copyright © 2010 John Wiley & Sons, Ltd. PMID:21080508

  16. Directionality Effect in Double Conditionals.

    PubMed

    Espino, Orlando; Sánchez-Curbelo, Isana; Bolaños-Medina, Alicia

    2015-01-01

    Directionality effect in deductive reasoning is a very well-known phenomenon that shows that the percentage of forward or backward inferences that participants make depends on the conditional form used. A new extension of the semantic hypothesis (Oberauer & Wilhelm, 2000) is presented to explain the directionality effect in double conditionals with different directionality. This hypothesis claims that the directional effect depends on which term plays the role of relatum. It also makes several novel claims which have been confirmed in three experiments: Experiments 1 and 2 showed there were more forward than backward inferences when the end-term that played the role of relatum was in the first premise, experiment 1: t (45) = 2.73, p < .01, experiment 2: t (38) = 12.06, p < .05, but there were more backward than forward inferences when the end-term that played the role of relatum was in the second premise, experiment 1: t (45) = 2.84, p < .01, experiment 2: t (38) = 2.21, p < .04. Experiment 3 showed that there was no directional effect when both end-terms played the role of relatum, t (34) = 1.39, p = .17, or when both middle-terms (or neither of the end-terms) played the role of relatum, t (34) = .78, p = .44. These experiments confirmed the predictions of the new extension of the semantic hypothesis. PMID:26239471

  17. 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

  18. 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.

  19. 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. PMID:25829623

  20. Total ozone column, water vapour and aerosol effects on erythemal and global solar irradiance in Marsaxlokk, Malta

    NASA Astrophysics Data System (ADS)

    Bilbao, Julia; Román, Roberto; Yousif, Charles; Mateos, David; de Miguel, Argimiro

    2014-12-01

    Observations of erythemal (UVER; 280-400 nm) and total solar shortwave irradiance (SW; 305-2800 nm), total ozone column (TOC), water vapour column (w), aerosol optical depth (AOD) and Ångström exponent (α) were carried out at Marsaxlokk, in south-east Malta. These measurements were recorded during a measurement campaign between May and October 2012, aimed at studying the influence of atmospheric compounds on solar radiation transfer through the atmosphere. The effects of TOC, AOD and w on UVER and SW (global, diffuse and direct) irradiance were quantified using irradiance values under cloud-free conditions at different fixed solar zenith angles (SZA). Results show that UVER (but not SW) irradiance correlates well with TOC. UVER variations ranged between -0.24% DU-1 and -0.32% DU-1 with all changes being statistically significant. Global SW irradiance varies with water vapour column between -2.44% cm-1 and -4.53% cm-1, these results proving statistically significant and diminishing when SZA increases. The irradiance variations range between 42.15% cm-1 and 20.30% cm-1 for diffuse SW when SZA varies between 20° and 70°. The effect of aerosols on global UVER is stronger than on global SW. Aerosols cause a UVER reduction of between 28.12% and 52.41% and a global SW reduction between 13.46% and 41.41% per AOD550 unit. Empirical results show that solar position plays a determinant role, that there is a negligible effect of ozone on SW radiation, and stronger attenuation by aerosol particles in UVER radiation.

  1. Combining effective media and multi-phase methods of Lattice Boltzmann modelling for the characterisation of liquid-vapour dynamics in multi-length scale heterogeneous structural materials

    NASA Astrophysics Data System (ADS)

    McDonald, P. J.; Turner, M. N.

    2016-01-01

    The combination of the lattice Boltzmann Shan-Chen pseudo-potential method for multiphase fluids (Shan and Chen 1993 Phys. Rev. E 47 1815) and a grey or partial bounce back lattice Boltzmann algorithm for effective media (Walsh et al 2009 Comput. Geosci. 35 1186), is demonstrated for application to liquid-vapour fluid dynamics in porous media with porosity spanning a very wide range of length scales. Liquid / vapour distributions in cellular like structures with cell walls of reduced permeability are seen to follow expectation.

  2. Effect of resin hydrophilicity on water-vapour permeability of dental adhesive films.

    PubMed

    King, Nigel M; Hiraishi, Noriko; Yiu, Cynthia K Y; Pashley, Edna L; Loushine, Robert J; Rueggeberg, Fred A; Pashley, David H; Tay, Franklin R

    2005-10-01

    This study examined the water-vapour permeability of thin polymerized resin films fabricated from five co-monomer blends of increasing degrees of hydrophilicity, as measured by their Hoy's solubility parameters. Neat resin films were prepared from five experimental light-curable resins (n = 10). Each film was mounted in a Fisher permeability cup with 8 g of water placed inside the cup. The experiments were conducted in a modified twin-outlet desiccator connected to a vacuum pump in one outlet to permit a continuous airflow to encourage water evaporation. Weight losses by water evaporation were measured at 3, 6, 9, 24, 30, and 48 h by using an analytical balance. Additional resin films were examined by using transmission electron microscopy (TEM) after immersion in ammoniacal silver nitrate. A significant correlation was observed between the cumulative water loss at 48 h and the Hoy's total cohesive energy density (delta(t)). Transmission electron microscopy revealed silver-filled channels along film peripheries and silver grains of decreasing dimensions toward the film centres in co-monomer blends 3, 4, and 5 of increasing hydrophilicity. Hydrophilic dentin adhesives polymerized in thin films are prone to water loss by evaporation. This probably accounts for the water droplets seen on the surface of vital-bonded dentin after the application of simplified dentin adhesives. PMID:16202033

  3. 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

  4. 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.

  5. 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

  6. Electron swarm parameters in water vapour

    NASA Astrophysics Data System (ADS)

    Hasegawa, H.; Date, H.; Shimozuma, M.

    2007-04-01

    Electron swarm parameters, such as the drift velocity and the ionization coefficient, in water vapour have been measured for relatively wide ranges in reduced electric fields (E/N) at room temperature. The drift velocity (Wm) was obtained based upon the arrival-time spectra of electrons by using a double-shutter drift tube for the E/N from 60 to 1000 Td, while the first and second ionization coefficients (α and γ) were determined by the steady-state Townsend method from 50 to 3000 Td. A comparison between the results and other data in the literature shows that our results for both the drift velocity and the effective ionization coefficient are lower than those of the other data in the above ranges.

  7. 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

  8. 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

  9. 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.

  10. 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

  11. 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

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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, rc = 2.5, 3, 4, and 5σ. In addition, we have also considered cutoff distances rc = 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

  13. Electron Transport in Water Vapour

    NASA Astrophysics Data System (ADS)

    Kawaguchi, Satoru; Satoh, Kohki; Itoh, Hidenori

    2015-09-01

    Sets of electron collision cross sections for water vapour previously reported are examined by comparing calculated electron swarm parameters with measured parameters. Further, reliable cross section set of water vapour is estimated by the electron swarm method using Monte Carlo simulation to ensure the accuracy of the swarm parameter calculation. The values of an electron drift velocity, a longitudinal diffusion coefficient, and an effective ionisation coefficient calculated from Yousfi and Benabdessadok's set and those calculated from Itikawa and Mason's set do not necessarily agree with measured data. A new cross section set of water vapour, which consists of three kinds of rotational excitation, two kinds of vibrational excitation, three kinds of electron attachment, twenty-six kinds of electronic excitation, and six kinds of ionisation cross sections, and an elastic collision cross section, is estimated, and an anisotropic electron scattering for elastic and rotational excitation collision is considered. The swarm parameters calculated from the estimated cross section set is in good agreement with measured data in a wide range of reduced electric field.

  14. 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

  15. 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

  16. 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

  17. 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

  18. Experimental evidence of the double-porosity effects in geomaterials

    NASA Astrophysics Data System (ADS)

    Tran Ngoc, Tien; Lewandowska, Jolanta; Bertin, Henri

    2014-06-01

    Double-porosity is an important characteristic of microstructure in a large range of geomaterials. It designs porous media with connected fissures/fractures or aggregated soils. The origin of double-porosity can be natural or/and it can result from mechanical, chemical or biological damage. The presence of double-porosity can significantly affect the behaviour of geomaterials. In this paper we provide an experimental evidence of the double-porosity effects by performing laboratory experiments. Series of tracer dispersion experiments (in saturated and unsaturated steady-state water flow conditions) in a physical model of double-porosity geomaterial were carried out. For the comparative purposes, experiments of the same type were also performed in a singleporosity model medium. The results clearly showed that the double-porosity microstructure leads to the non-Fickian behaviour of the tracer (early breakthrough and long tail) in both saturated and unsaturated cases.

  19. EDITORIAL Metal vapour in atmospheric-pressure arcs Metal vapour in atmospheric-pressure arcs

    NASA Astrophysics Data System (ADS)

    Murphy, Anthony B.

    2010-11-01

    low-voltage circuit breakers, metal vapour is formed by evaporation of the electrodes (runners) and the splitter plates, and can have a major influence on the dynamics of arc motion. While the influence of metal vapour on arcs is now understood in general terms, there are many unresolved questions. Areas in which improvements and new insights are required include: diagnostic techniques for measurements of arc properties in the presence of metal vapour, and understanding of the possible deviations from local thermodynamic equilibrium and their influence on such measurements; measurements of the influence of metal vapour in circuit breakers, in which the arc occurs within a solid enclosure, and in gas-metal arc welding, in which the formation of metal droplets and arc instabilities can disrupt standard techniques; determination of the concentration of metal vapour species in different types of arcs; understanding of the relative importance of the different effects of metal vapour (such as increased radiation and electrical conductivity, and the rapid influx of relatively cold gas) on the arc for different configurations; the influence of metal vapour on the electrode boundary and sheath regions; the treatment of radiative and mass transport in computational models; understanding and treatment of the vaporization, condensation and nucleation of metal species, and methods of incorporation of these processes in computational models. In this cluster issue, many of these and related issues are addressed. The twelve contributions cover gas-metal arc welding, gas-tungsten arc welding and low-voltage circuit breakers, and include both experimental and computational studies, in some cases with striking results. A review of the influence of metal vapour in welding arcs is followed by three accounts of spectroscopic measurements of gas-metal arc welding, which are difficult to perform and until recently have rarely been attempted. The application of spectroscopic techniques to

  20. 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.

  1. 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)

  2. Effective desynchronization by means of double-pulse phase resetting

    NASA Astrophysics Data System (ADS)

    Tass, P. A.

    2001-01-01

    A double-pulse stimulation technique is presented here for the first time which makes it possible to effectively desynchronize a synchronized cluster of globally coupled phase oscillators in the presence of noise. The first, stronger pulse of the double pulse restarts the cluster independently of its initial dynamic state. The second, weaker pulse desynchronizes the cluster by hitting it in a vulnerable state. After the desynchronization the cluster tends to resynchronize since the incoherent state is unstable. Nevertheless, repeated administration of double pulses blocks the cluster's resynchronization. This approach can directly be applied to real data. Accordingly, a demand-controlled deep-brain double-pulse stimulation technique is suggested for the therapy of patients suffering from Parkinson's disease or essential tremor.

  3. Choke position effects in double-choked circular waveguide antennas

    NASA Astrophysics Data System (ADS)

    Miyata, K.; Suzuki, M.

    1984-06-01

    A number of studies have been conducted regarding choke-loaded circular waveguide antennas. Aoki et al. (1970) have obtained improved results with respect to the beam circularity and the wide-angle radiation properties. Cowan (1973) suggested the employment of suitable compact, double choked feeds for frequency-reuse application. Further improvements can apparently be obtained by loading double chokes on a circular waveguide. The present investigation is concerned with the variation of the radiated fields for various choke positions in double-choked circular waveguide antennas. In the case of double-choked small circular waveguide antennas, it is found that the choke position has a pronounced effect on the radiation properties. Particularly sensitive to the choke position is the cross-polar level.

  4. 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. PMID:26702788

  5. 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.

  6. 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

  7. 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

  8. Effect of V/III ratio on the growth of (11 2 bar 2) AlGaN by metalorganic vapour phase epitaxy

    NASA Astrophysics Data System (ADS)

    Dinh, Duc V.; Alam, S. N.; Parbrook, P. J.

    2016-02-01

    The effect of V/III ratio on the growth and properties of AlGaN layers grown on (112bar2) AlN templates grown on (101bar0) sapphire by metalorganic vapour phase epitaxy was studied. The surface morphology of the (112bar2) AlGaN layers and the (112bar2) AlN templates showed an undulation along [ 1 1 bar 00 ] AlGaN , AlN. The Al-content and thickness of the layers increased with decreasing V/III ratio due to a reduction in the parasitic reactions of the precursors. The Al-content of the (112bar2) layers was found to be in the range of 29.5-47.9%, which is lower than the composition of the simultaneously grown (0001) reference layers (30.4-58.0%). This was attributed to a higher density of cation (nitrogen) dangling bonds on the (112bar2) surface. Low temperature photoluminescence measurements of the (112bar2) layers showed an emission wavelength that shifts gradually from 273 nm to 306 nm with increasing V/III ratio. A decreased PL intensity of the layers with decreasing V/III ratio was attributed to an increase in cation vacancies. The Stokes-shift of the (112bar2) layers was estimated to be about 60-194 meV, and this shift increases with increasing Al-content (decreasing V/III ratio) correlated to an increased exciton localization.

  9. Polarization effects in double open-charm production at LHCb

    NASA Astrophysics Data System (ADS)

    Echevarría, Miguel G.; Kasemets, Tomas; Mulders, Piet J.; Pisano, Cristian

    2015-04-01

    Double open-charm production is one of the most promising channels to disentangle single from double parton scattering (DPS) and study different properties of DPS. Several studies of the DPS contributions have been made. A missing ingredient so far has been the study of polarization effects, arising from spin correlations between the two partons inside an unpolarized proton. We investigate the impact polarization has on the double open-charm cross section. We show that the longitudinally polarized gluons can give significant contributions to the cross section, but for most of the considered kinematic region only have a moderate effect on the shape. We compare our findings to the LHCb data in the D 0 D 0 final state, identify observables where polarization does have an impact on the distribution of the final state particles, and suggest measurements which could lead to first experimental indications of, or limits on, polarization in DPS.

  10. 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. PMID:26872498

  11. A eutectic gold vapour laser

    NASA Astrophysics Data System (ADS)

    Tou, T. Y.; Cheak, K. E.; Low, K. S.

    This paper presents a eutectic gold vapour laser (EGVL) which uses the eutectic alloy of gold and silicon, Au/3.15Si, as the lasant. It was observed that, at low input power operation, the presence of the silicon vapour could increase the output of the 627.8 nm laser line by (50-60)% when compared with a gold vapour laser (GVL) which uses pure gold as the lasant. The improved laser output for the EGVL may be explained by an increased electron density, as a result of Penning ionization of silicon atoms. However, for higher input power operation, the EGVL showed a slower rate of increase in its laser output power and was overtaken by GVLs at a tube operating temperature of around 1650°C. This may be explained by a lowering of the electron temperature owing to increasing inelastic collisions between the electrons and silicon atoms which, although excited, may not produce additional electrons.

  12. Growth of multiwalled carbon nanotube arrays by chemical vapour deposition over iron catalyst and the effect of growth parameters

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, J. K.; Pandian, P. S.; Padaki, V. C.; Bhusan, H.; Rao, K. U. B.; Xie, J.; Abraham, J. K.; Varadan, V. K.

    2009-04-01

    Multiwalled carbon nanotube (CNT) arrays were grown by catalytic thermal decomposition of acetylene, over Fe-catalyst deposited on Si-wafer in the temperature range 700-750 °C. The growth parameters were optimized to obtain dense arrays of multiwalled CNTs of uniform diameter. The vertical cross-section of the grown nanotube arrays reveals a quasi-vertical alignment of the nanotubes. The effect of varying the thickness of the catalyst layer and the effect of increasing the growth duration on the morphology and distribution of the grown nanotubes were studied. A scotch-tape test to check the strength of adhesion of the grown CNTs to the Si-substrate surface reveals a strong adhesion between the grown nanotubes and the substrate surface. Transmission electron microscopy analysis of the grown CNTs shows that the grown CNTs are multiwalled nanotubes with a bamboo structure, and follow the base-growth mechanism.

  13. 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.

  14. 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

  15. Acute effects of exposure to vapours of standard and dearomatized white spirits in humans. 2. Irritation and inflammation.

    PubMed

    Ernstgård, Lena; Iregren, Anders; Juran, Stephanie; Sjögren, Bengt; van Thriel, Christoph; Johanson, Gunnar

    2009-04-01

    Low aromatic and dearomatized white spirits (deWS) are often considered less hazardous to health than 'standard' or aromatic white sprit (stdWS, 15-20% aromatics). However, data on health effects of deWS in humans are sparse and controlled exposure studies are lacking. The aim of this study was to compare deWS and stdWS with respect to irritation and inflammation. Six female and six male healthy volunteers were exposed on five occasions in balanced order to 100 or 300 mg m(-3) deWS (0.002% aromatics) or stdWS (19% aromatics), or to clean air, for 4 h at rest. Discomfort in the eyes, nose and throat and breathing difficulty were assessed by ratings on visual analogue scales. The only significant increases in ratings (compared to clean air) were seen for eye irritation at the high stdWS exposure and for solvent smell at all but the low deWS exposure. Excluding smell, all average ratings were at the lower end of the 0-100 mm scale, and did not exceed the verbal expression 'somewhat'. Ratings during stdWS exposure tended to be higher than during deWS exposure. No exposure-related effects on pulmonary function, nasal swelling, nasal airway resistance, breathing frequency, blinking frequency, plasma inflammatory markers (C-reactive protein, interleukin-6) or biochemical variables (sodium, potassium, amylase, creatine kinase, urate) were seen. In conclusion, stdWS appears to be slightly more irritating than deWS. This could, however, not be confirmed by objective measurements. PMID:19086013

  16. Effects of double-layer polarization on ion transport.

    PubMed

    Hainsworth, A H; Hladky, S B

    1987-01-01

    It has been proposed that changes in ionic strength will alter the shape of current-voltage relations for ion transport across a lipid membrane. To investigate this effect, we measured currents across glyceryl monooleate membranes at applied potentials between 10 and 300 mV using either gramicidin and 1 mM NaCl or valinomycin and 1 mM KCl. A bridge circuit with an integrator as null detector was used to separate the capacitative and ionic components of the current. The changes in the current-voltage relations when ionic strength is varied between 1 and 100 mM are compared with predictions of Gouy-Chapman theory for the effects of these variations on polarization of the electrical diffuse double-layer. Double-layer polarization accounts adequately for the changes observed using membranes made permeable by either gramicidin or valinomycin. PMID:2432953

  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. Electrical double layer effects on ion transfer reactions.

    PubMed

    Lin, Chuhong; Laborda, Eduardo; Batchelor-McAuley, Christopher; Compton, Richard G

    2016-04-14

    The potential dependence of the thermodynamics and kinetics of ion transfer reactions as influenced by the electrical double layer are studied via two-dimensional free energy surfaces calculated with an extension of the Anderson-Newns Hamiltonian. The Gibbs energy difference between the reduced and oxidized states, the activation barrier and the resulting current-potential curves are investigated as a function of the potential of zero charge and the Debye length, which are applied to characterize the external electric field. It is found that the current-potential curves of different redox systems are distinctly affected by the electrical double layer depending on the charges of the solution-phase and adsorbed species. For the redox couples sensitive to double layer effects, it is shown that the external electric field can cause a decrease in the driving force for the ion transfer process, which leads to the reversible peak current deviating significantly from the ideal, Nernstian predictions and the effective transfer coefficient being less than 1 even though the ion transfer is kinetically fully reversible. PMID:27001630

  19. 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.

  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. The seasonal cycle of water vapour on Mars from assimilation of Thermal Emission Spectrometer data

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

    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 μm 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 LS=240-260°. 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.

  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. Effect of chocolate in migraine: a double-blind study

    PubMed Central

    Moffett, A. M.; Swash, M.; Scott, D. F.

    1974-01-01

    The effect of chocolate on a group of volunteer migrainous subjects, who had observed that headache regularly occurred after the ingestion of small amounts of cocoa products, was investigated. Two separate studies were carried out in a double-blind placebo controlled manner. Only 13 headaches occurred to chocolate alone in 80 subject sessions, and only two subjects responded consistently to chocolate in the two studies. This suggests that chocolate on its own is rarely a precipitant of migraine. Other possible implications of the results are also discussed. PMID:4838915

  4. Effect of double layers on magnetosphere-ionosphere coupling

    NASA Technical Reports Server (NTRS)

    Lysak, Robert L.; Hudson, Mary K.

    1987-01-01

    The Earth's auroral zone contains dynamic processes occurring on scales from the length of an auroral zone field line which characterizes Alfven wave propagation to the scale of microscopic processes which occur over a few Debye lengths. These processes interact in a time-dependent fashion since the current carried by the Alfven waves can excite microscopic turbulence which can in turn provide dissipation of the Alfven wave energy. This review will first describe the dynamic aspects of auroral current structures with emphasis on consequences for models of microscopic turbulence. A number of models of microscopic turbulence will be introduced into a large-scale model of Alfven wave propagation to determine the effect of various models on the overall structure of auroral currents. In particular, the effects of a double layer electric field which scales with the plasma temperature and Debye length is compared with the effect of anomalous resistivity due to electrostatic ion cyclotron turbulence in which the electric field scales with the magnetic field strength. It is found that the double layer model is less diffusive than in the resistive model leading to the possibility of narrow, intense current structures.

  5. Antimicrobial action of essential oil vapours and negative air ions against Pseudomonas fluorescens.

    PubMed

    Tyagi, A K; Malik, A

    2010-10-15

    The aim of this study was to investigate the antibacterial activity of essential oil (in liquid as well as in vapour phase) and negative air ions (NAI) against Pseudomonas fluorescens. The combined effect of NAI with essential oil vapour was also investigated to determine kill time and morphological changes in bacterial cells. The MIC of Cymbopogon citratus (0.567 mg/ml), Mentha arvensis (0.567 mg/ml), Mentha piperita (1.125 mg/ml) and Eucalyptus globulus (2.25 mg/ml) was studied via the agar dilution method. To estimate the antibacterial activity of essential oils in the vapour phase, agar plates inoculated with P. fluorescens were incubated with various concentrations of each essential oil vapour and zone of inhibition was recorded. Further, in order to assess the kill time, P. fluorescens inoculated agar plates were exposed to selected bactericidal essential oil vapour and NAI, separately, in an air-tight chamber. A continuous decrease in bacterial count was observed over time. A significant enhancement in the bactericidal action was observed by exposure to the combination of essential oil vapour and NAI as compared to their individual action. Scanning electron microscopy was used to study the alteration in morphology of P. fluorescens cells after exposure to C. citratus oil vapour, NAI, and combination of C. citratus oil vapour and NAI. Maximum morphological deformation was found due to the combined effect of C. citratus oil vapour and NAI. This study demonstrates that the use of essential oils in the vapour phase is more advantageous than the liquid phase. Further the antibacterial effect of the essential oil vapours can be significantly enhanced by the addition of NAI. The work described here offers a novel and efficient approach for control of bacterial contamination that could be applied for food stabilization practices. PMID:20850191

  6. Contact effects in spin transport along double-helical molecules

    NASA Astrophysics Data System (ADS)

    Guo, Ai-Min; Díaz, E.; Gaul, C.; Gutierrez, R.; Domínguez-Adame, F.; Cuniberti, G.; Sun, Qing-feng

    2014-05-01

    We report on spin transport along double-helical molecular systems by considering various contact configurations and asymmetries between the two helical strands in the regime of completely coherent charge transport. Our results reveal that no spin polarization appears in two-terminal molecular devices when coupled to one-dimensional electrodes. The same holds in the case of finite-width electrodes if there is a bottleneck of one single site in the system electrode-molecule-electrode. Then, additional dephasing is necessary to induce spin-filtering effects. In contrast, nonzero spin polarization is found in molecular devices with multiple terminals or with two finite-width electrodes, each of them connected to more than one site of the molecule. The magnitude of spin polarization can be enhanced by increasing the asymmetry between the two strands. We point out that the spin-filtering effects could emerge in double-helical molecular devices at low temperature without dephasing by a proper choice of the electrode number and the connection between the molecule and the electrodes.

  7. Palliative care, double effect and the law in Australia.

    PubMed

    White, B P; Willmott, L; Ashby, M

    2011-06-01

    Care and decision-making at the end of life that promotes comfort and dignity is widely endorsed by public policy and the law. In ethical analysis of palliative care interventions that are argued potentially to hasten death, these may be deemed to be ethically permissible by the application of the doctrine of double effect, if the doctor's intention is to relieve pain and not cause death. In part because of the significance of ethics in the development of law in the medical sphere, this doctrine is also likely to be recognized as part of Australia's common law, although hitherto there have been no cases concerning palliative care brought before a court in Australia to test this. Three Australian States have, nonetheless, created legislative defences that are different from the common law with the intent of clarifying the law, promoting palliative care, and distinguishing it from euthanasia. However, these defences have the potential to provide less protection for doctors administering palliative care. In addition to requiring a doctor to have an appropriate intent, the defences insist on adherence to particular medical practice standards and perhaps require patient consent. Doctors providing end-of-life care in these States need to be aware of these legislative changes. Acting in accordance with the common law doctrine of double effect may not provide legal protection. Similar changes are likely to occur in other States and Territories as there is a trend towards enacting legislative defences that deal with the provision of palliative care. PMID:21707893

  8. 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.

  9. 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

  10. Double layer effects on metal nucleation in deep eutectic solvents.

    PubMed

    Abbott, Andrew P; Barron, John C; Frisch, Gero; Gurman, Stephen; Ryder, Karl S; Fernando Silva, A

    2011-06-01

    The electrodeposition of zinc has been studied in two deep eutectic solvents. Unlike the metals studied to date in these liquids, zinc electrodeposition is not mass transport limited and the morphology of the deposit differs in the two liquids. This study shows that changing the concentration of solute affects the physical properties of the liquid to different extents although this is found to not effect the morphology of the metal deposited. EXAFS was used to show that the speciation of zinc was the same in both liquids. Double layer capacitance studies showed differences between the two liquids and these are proposed to be due to the adsorption of a species on the electrode which is thought to be chloride. The differences in zinc morphology is attributed to blocking of certain crystal faces leading to deposition of small platelet shaped crystals in the glycol based liquid. PMID:21519629

  11. 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.

  12. Water-lithium bromide double-effect absorption cooling analysis

    NASA Astrophysics Data System (ADS)

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

    1980-12-01

    A numerical model was developed for the transient simulation of the double-effect, water-lithium bromide absorption cooling machine and was used 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 variables considered 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 indicates 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.

  13. Characteristics of Single/Double-Effect Combination Absorption Refrigerator

    NASA Astrophysics Data System (ADS)

    Kimijima, Shingi; Waragai, Shisei; Uekusa, Tsuneo; Nakao, Masaki; Kawai, Sunao

    This report refers to the single/double-effect combination absorption refrigerator, which is driven by waste heat from phosphoric acid fuel cells, and investigates the influence of heat supply conditions, for the purpose of the effectual utilization of the low grade waste heat such as hot water (60~90([°C]). Since waste heat from fuel cells is recovered in two forms of steam and hot water, there is a characteristic of mutual intervention between steam and hot water in absorption refrigeration cycle. For effective use of waste heat, it becomes necessary to clarify this characteristic of mutual intervention. Accordingly, we inquire the effect of heat supply conditions on above mentioned characteristic by simulation. In addition to this, the cooling performance of the absorption refrigerators with two different ways to use hot water (preheating of solution type and generating refrigerant vapor in the low temperature generator type) is investigated. Through out the research, some knowledges for effective use of low grade waste heat are obtained

  14. Disinsection of Aircraft with a Mechanical Dispenser of DDVP Vapour*

    PubMed Central

    Schoof, H. F.; Jensen, J. A.; Porter, J. E.; Maddock, D. R.

    1961-01-01

    In-flight and on-ground tests in commercial aircraft have demonstrated the feasibility of using DDVP (O,O-dimethyl-2,2-dichlorovinyl phosphate) vapour for disinsection purposes. Treatment of the passenger compartments of DC-6 and DC-7 aeroplanes was accomplished by passing cabin air through a fibrous cartridge impregnated with DDVP. The DDVP-charged air stream was distributed from the cartridge into the passenger compartment through small orifices, spaced 3 feet apart, in metal tubing suspended at ceiling height along the longitudinal axis of the cabin. Further distribution of the vapour was effected by the air currents of the ventilating system. During in-flight tests, vapour concentrations of 0.20 and 0.24 μg of DDVP per litre of air gave 100% mortalities of caged houseflies located at 12 sites at three different levels and exposed for 30 minutes. No effect of the vapour was noticed on the cholinesterase levels of three individuals exposed to the treatment during 24 tests. Imagesp624-a PMID:13748488

  15. 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.

  16. 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.

  17. Model analysis of a double-stage Hall effect thruster with double-peaked magnetic field and intermediate electrode

    SciTech Connect

    Perez-Luna, J.; Hagelaar, G. J. M.; Garrigues, L.; Boeuf, J. P.

    2007-11-15

    A hybrid fluid-particle model has been used to study the properties of a double-stage Hall effect thruster where the channel is divided into two regions of large magnetic field separated by a low-field region containing an intermediate, electron-emitting electrode. These two features are aimed at effectively separating the ionization region from the acceleration region in order to extend the thruster operating range. Simulation results are compared with experimental results obtained elsewhere. The simulations reproduce some of the measurements when the anomalous transport coefficients are adequately chosen. However, they raise the question of a complete separation of the ionization and acceleration regions and the necessity of an electron-emissive intermediate electrode. The calculation method for the electric potential in the hybrid model has been improved with respect to our previous work and is capable of a complete two-dimensional description of the magnetic configurations of double-stage Hall effect thrusters.

  18. 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

  19. 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

    2016-05-01

    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. PMID:26507257

  20. 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.

  1. Parametric analysis of a double-effect steam absorption chiller

    NASA Astrophysics Data System (ADS)

    Mohammed Salih Ahmed, Mojahid Sid Ahmed; Gilani, Syed Ihtsham Ul-Haq

    2012-06-01

    The development in the field of refrigeration and cooling systems based on absorption cycles has attained its own internal dynamic in the last decade. A major obstacle for developing model is the lack of available component specifications. These specifications are commonly proprietary of the chiller's manufacturers and normally the available information is not sufficient. This work presented a double-effect parallel-flow-type steam absorption chiller model based on thermodynamic and energy equations. The chiller studied is 1250 RT (Refrigeration Tons) using lithium bromide -water as working pair. The mathematical equations that govern the operation of the steam absorption chiller are developed, and from the available design data the values of the overall heat transfer coefficient multiplied by the heat exchanger surface area and the characteristics of each component of the absorption chiller at the design point are calculated. For thermo physical and thermodynamic properties for lithium bromide-water solution, set of computationally efficient formulations are used. The model gives the required information about temperature, concentration, and flow rate at each state point of the system. The model calculates the heat load at each component as well as the performance of the system.

  2. Magneto Optical Kerr Effect Measurement of Double Exchange Spring System

    NASA Astrophysics Data System (ADS)

    Yuan, Hanming; Gu, Jiyeong

    2012-11-01

    Magnetic property of the symmetric Double Exchange Spring System, soft(S)/hard(H)/soft(S) magnetic layers Glass/NiFe (bottom Py)/SmFe/NiFe (top Py), was investigated using Magneto Optical Kerr Effect (MOKE) measurement. In order to produce a symmetric non-collinearity in magnetization, the thicknesses of the two Py layers are controlled to be the same during the deposition. Due to the finite skin depth of the laser used in MOKE measurement magnetic hysteresis loop for each Py layer can be measured separately by adjusting the right thickness of the layers. First of all, we found the magnetic hysteresis loops for the bottom and the top Py layers are not the same. Moreover, we found that the coercivity of the bottom Py measured from MOKE is closer to the coercivity of the first switching measured from Alternating Gradient Magnetometer (AGM) and is much smaller than that of the top Py from MOKE; the coercivity of the top Py from MOKE is closer to that of the second switching from AGM. These show that the non-collinearity provided by the two soft layers is not symmetric in reality even with a symmetric structure. The experimental observations might be due to the difference in the growing environment between the bottom Py layer and the top Py layer.

  3. Vapour pressure and adiabatic cooling from champagne: slow-motion visualization of gas thermodynamics

    NASA Astrophysics Data System (ADS)

    Vollmer, Michael; Möllmann, Klaus-Peter

    2012-09-01

    We present two simple demonstration experiments recorded with high-speed cameras in the fields of gas dynamics and thermal physics. The experiments feature vapour pressure effects as well as adiabatic cooling observed upon opening a bottle of champagne.

  4. Vapour phase: a potential future use for essential oils as antimicrobials?

    PubMed

    Laird, K; Phillips, C

    2012-03-01

    Essential oil (EO) vapours have been known for their antimicrobial properties since the 4th century B.C.; however, it was not until the early 1960s that research into the potential of these volatile oils was explored. More recently, the use of EOs such as tea tree, bergamot, lavender and eucalyptus in vapour form has been shown to have antimicrobial effects against both bacteria and fungi, with range of methods being developed for dispersal and efficacy testing. To date, many applications for EO vapours as antimicrobials have been identified including in the food and clinical arenas. PMID:22133088

  5. 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}.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. Magneto Optical Kerr Effect measurement of double exchange spring system

    NASA Astrophysics Data System (ADS)

    Yuan, Hanming

    Magnetic property of the symmetric Double Exchange Spring System, soft(S)/hard(H)/soft(S) ferromagnetic layers NiFe (Py)/SmFe/NiFe (Py), was investigated using Magneto Optical Kerr Effect (MOKE) measurement. Exchange spring magnet, H/S bilayer, shows a unique magnetic hysteresis curve due to the non-collinear magnetization developed by magnetic coupling of the two layers. In order to produce a symmetric non-collinearity in magnetization, the thicknesses of the two soft layers are controlled to be the same during the deposition. Due to the finite skin depth of MOKE measurement magnetic hysteresis loop for each soft layer could be measured separately by adjusting the right thickness of the layers. To measure the bottom soft layer transparent glass substrate was used for thin film deposition. We first observed an asymmetric hysteresis loop of the double exchange spring system by MOKE measurement. This is due to the existence of quadratic MOKE (QMOKE) signal caused by the in-plane magnetic anisotropy. Linear MOKE (LMOKE) and QMOKE signal were separated from the general MOKE signal using a symmetry operation. In general, the samples that have the induced easy axis have less significant QMOKE signal than those that do not have the easy axis. Second, from the LMOKE measurement, we found that the magnetic hysteresis loops for the bottom and the top S layers are not the same. The magnetic hysteresis loop from LMOKE measurements data was compared with the one measured by Alternating Gradient Magnetometer (AGM). AGM measures the total magnetization of the whole structure. Our data shows that the coercivity of the bottom S measured from LMOKE is closer to the coercivity of the first switching measured from AGM and is much smaller than that of the top S from MOKE. The coercivity of the top S from LMOKE is closer to that of the second switching from AGM. This indicates that the top S is, to some extent, strongly coupled with the hard layer causing them to switch together; while

  11. The rotational partition function of the symmetric top and the effect of K doubling thereon

    NASA Astrophysics Data System (ADS)

    Martin, J. M. L.; François, J. P.; Gijbels, R.

    1991-12-01

    McDowell's earlier derivation of the partition function for a nonrigid symmetric top has been extended with a fourth-order correction for centrifugal distortion and correction terms for K doubling. Comparison with direct numerical summation (including K-doubling effects) indicates that the inclusion of the fourth-oder term is necessary to ensure high accuracy in the computed enthalpy function and heat capacity above 2000 K, as well as that the effect of K doubling is very small at practical temperatures. The only effect of any practical importance is that of d2 for molecules with fourfold symmetry: the present approximate expressions represent this effect quite well.

  12. 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.

  13. 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…

  14. Phase effects in double ionization by strong short pulses

    NASA Astrophysics Data System (ADS)

    Eckhardt, Bruno; Prauzner-Bechcicki, Jakub S.; Sacha, Krzysztof; Zakrzewski, Jakub

    2010-05-01

    We consider double ionization induced by strong single cycle pulses within quantum calculations of a reduced dimensionality model. Changes in the phase relation between the wave and the envelope affect the total ionization yield as well as the characteristics in the distribution of the outgoing momenta.

  15. 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

  16. 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

  17. 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. PMID:24849267

  18. 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.

  19. 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

  20. 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

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

    PubMed

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

    2016-01-01

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

  2. 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. PMID:23532500

  3. 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).

  4. The effect of a magnetic field gradient on anode double layers

    NASA Technical Reports Server (NTRS)

    Song, B.; Merlino, R. L.; D'Angelo, N.

    1992-01-01

    In experiments on anode (ionization) double layers in nonuniform magnetic fields it has been noted that the magnetic field gradient seems to stabilize the double layer position. This effect is further investigated in a Q machine in which the magnetic field geometry could be varied. It is found that the position of the double layers, along the axis of the device, could be controlled by changing the magnetic geometry. This effect is accounted for in a physical model which takes into account the effect of ion reflection by the magnetic mirror force in the region of magnetic field nonuniformity. This model is also able to account for variation of the double layer position when the neutral gas pressure is varied.

  5. Double proton transfer behavior and one-electron oxidation effect in double H-bonded glycinamide-formic acid complex.

    PubMed

    Li, Ping; Bu, Yuxiang

    2004-11-22

    The behavior of double proton transfer occurring in a representative glycinamide-formic acid complex has been investigated at the B3LYP/6-311 + + G( * *) level of theory. Thermodynamic and, especially, kinetic parameters, such as tautomeric energy, equilibrium constant, and barrier heights have been discussed, respectively. The relevant quantities involved in the double proton transfer process, such as geometrical changes, interaction energies, and intrinsic reaction coordinate calculations have also been studied. Computational results show that the participation of a formic acid molecule favors the proceeding of the proton transfer for glycinamide compared with that without mediate-assisted case. The double proton transfer process proceeds with a concerted mechanism rather than a stepwise one since no ion-pair complexes have been located during the proton transfer process. The calculated barrier heights are 11.48 and 0.85 kcal/mol for the forward and reverse directions, respectively. However, both of them have been reduced by 2.95 and 2.61 kcal/mol to 8.53 and -1.76 kcal/mol if further inclusion of zero-point vibrational energy corrections, where the negative barrier height implies that the reverse reaction should proceed with barrierless spontaneously, analogous to that occurring between glycinamide and formamide. Furthermore, solvent effects on the thermodynamic and kinetic processes have also been predicted qualitatively employing the isodensity surface polarized continuum model within the framework of the self-consistent reaction field theory. Additionally, the oxidation process for the double H-bonded glycinamide-formic acid complex has also been investigated. Contrary to that neutral form possessing a pair of two parallel intermolecular H bonds, only a single H bond with a comparable strength has been found in its ionized form. The vertical and adiabatic ionization potentials for the neutral complex have been determined to be about 9.40 and 8.69 e

  6. 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.

  7. RETRACTED — Studies on the effect of instability of divergence, pointing and amplitude of green and yellow radiation pulses of copper vapour laser in second harmonic and sum frequency conversion

    NASA Astrophysics Data System (ADS)

    Prakash, Om; Mahakud, Ramakanta; Nakhe, Shankar V.; Dixit, Sudhir K.

    2013-02-01

    This paper presents the effect of single pulse stability of divergence angle, beam pointing angle and amplitude of green and yellow radiation pulses of an unstable resonator copper vapour laser (CVL) oscillator in the sum frequency mixing and second harmonic. The conversion efficiency of sum frequency generation was lower compared to second harmonic processes despite larger fundamental power being used in sum frequency experiments. However the net UV power obtained at the sum frequency was higher than both of the second harmonic UV frequencies. Lower SFG conversion efficiency (12.4%—271 nm) compared to SHG (16.7%—255 nm, 14.5%—289 nm) of individual CVL radiations is attributed to difference in single pulse stability of beam pointing, divergence and amplitude fluctuation of both CVL radiations in addition to commonly known fact of spatio-temporal mis-match. At the same fundamental input power (2.7 W), higher SH conversion efficiency of yellow (12.7%) compared to green (11.0%) is attributed to its better single pulse stability of beam pointing and divergence.

  8. 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.

  9. 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.

  10. 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

  11. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-01-01

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

  13. 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)

  14. The vapour pressures of pure substances

    SciTech Connect

    Boublik, T.; Fried, V.; Hala, E.

    1984-01-01

    In this book a set of experimental vapour pressure data is collected. In addition, smoothed values of the pressures, as obtained by fitting the data to the Antoine equation, are presented together with the calculated boiling points and sets of the Antoine constants for each component.

  15. 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.

  16. Silicon nanowire arrays as learning chemical vapour classifiers.

    PubMed

    Niskanen, A O; Colli, A; White, R; Li, H W; Spigone, E; Kivioja, J M

    2011-07-22

    Nanowire field-effect transistors are a promising class of devices for various sensing applications. Apart from detecting individual chemical or biological analytes, it is especially interesting to use multiple selective sensors to look at their collective response in order to perform classification into predetermined categories. We show that non-functionalised silicon nanowire arrays can be used to robustly classify different chemical vapours using simple statistical machine learning methods. We were able to distinguish between acetone, ethanol and water with 100% accuracy while methanol, ethanol and 2-propanol were classified with 96% accuracy in ambient conditions. PMID:21673389

  17. The Effect of the Wall Contact and Post-Growth Cool-Down on Defects in CdTe Crystals Grown by 'Contactless' Physical Vapour Transport

    NASA Technical Reports Server (NTRS)

    Palosz, W.; Grasza, K.; Durose, K.; Halliday, D. P.; Boyall, N. M.; Dudley, M.; Raghothamachar, B.; Cai, L.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    A series of cadmium telluride crystals grown by physical vapor transport without contact with the ampoule walls and cooled at different rates were characterized using synchrotron X-ray topography, photoluminescence, and chemical etching. Strain from sticking to silica glass and its effect on the dislocation density is shown. It was found that very fast cool-down increases dislocation density by at least one order of magnitude. None of the samples had random dislocation distributions but coarse clumping of dislocations on the scale of more than 100 microns was more prevalent in slowly cooled crystals. Photoluminescence revealed that slow cooling favored the donor-acceptor luminescence involving complex A centers. This was diminished in fast cooled material; and effect presumed to be due to dislocation gettering. Fast cooling also enhanced the formation of shallow acceptors. Implications for Bridgman growth of CdTe and the vapor growth of CdZnTe are discussed briefly.

  18. 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

  19. Disconfirming (Double Bind) Effects of Incongruent Multi-Channel Messages.

    ERIC Educational Resources Information Center

    Rummel, Lynda; And Others

    In an experiment designed to explore the immediate disconfirming effects of strong and mild incongruent messages and the impact of certain contextual constraints on disconfirming effects, 192 male undergraduates evaluated videotaped examples of strong and mild sarcasm and joking and the complementary congruent forms of straightforward positive and…

  20. Electrically tunable Dicke effect in a double-ring resonator

    SciTech Connect

    Cetin, A. E.; Muestecaplioglu, Oe. E.

    2010-04-15

    We study the finite-element method analysis of the Dicke effect using numerical simulations in an all-optical system of an optical waveguide side-coupled to two interacting ring resonators in a liquid crystal environment. The system is shown to exhibit all the signatures of the Dicke effect under active and reversible control by an applied voltage.

  1. Pronounced antitumor effects and tumor radiosensitization of double suicide gene therapy.

    PubMed

    Rogulski, K R; Zhang, K; Kolozsvary, A; Kim, J H; Freytag, S O

    1997-11-01

    The efficacy of HSV-1 thymidine kinase (TK) and Escherichia coli cytosine deaminase (CD) suicide gene therapies as cancer treatments are currently being examined in humans. We demonstrated previously that compared to single suicide gene therapy, greater levels of targeted cytotoxicity and radiosensitization can be achieved in vitro by genetically modifying tumor cells to express CD and HSV-1 TK concomitantly, as a fusion protein. In the present study, the efficacy of the combined double suicide gene therapy/radiotherapy approach was examined in vivo. Nude mice were injected either s.c. or i.m. with 9L gliosarcoma cells expressing an E. coli CD/HSV-1 TK fusion gene. Double suicide gene therapy using 5-fluorocytosine (500 mg/kg) and ganciclovir (30 mg/kg) proved to be markedly better at delaying tumor growth and achieving a tumor cure than single suicide gene therapy, which used 5-fluorocytosine or ganciclovir administered independently. Importantly, double suicide gene therapy was highly effective against large experimental tumors (>2 cm3), reducing tumor volume an average of 99% and producing a 40% tumor cure. Moreover, double suicide gene therapy profoundly potentiated the antitumor effects of radiation. The results indicate that double suicide gene therapy, particularly when coupled with radiotherapy, may represent a highly effective means of eradicating tumors. PMID:9815600

  2. Effects of doubled carbon dioxide on rainfall responses to radiative processes of water clouds

    NASA Astrophysics Data System (ADS)

    Li, Xiaofan; Li, Tingting; Lou, Lingyun

    2014-12-01

    The effects of doubled carbon dioxide on rainfall responses to radiative processes of water clouds are investigated in this study. Two groups of two-dimensional cloud-resolving model sensitivity experiments with regard to pre-summer heavy rainfall around the summer solstice and tropical rainfall around the winter solstice are conducted and their five-day averages over the model domain are analyzed. In the presence of radiative effects of ice clouds, doubled carbon dioxide changes pre-summer rainfall from the decrease associated with the enhanced atmospheric cooling to the increase associated with the enhanced infrared cooling as a result of the exclusion of radiative effects of water clouds. Doubled carbon dioxide leads to the reduction in tropical rainfall, caused by the removal of radiative effects of water clouds through the suppressed infrared cooling. In the absence of radiative effects of ice clouds, doubled carbon dioxide changes pre-summer rainfall from the increase associated with the strengthened atmospheric warming to the decrease associated with the weakened release of latent heat caused by the elimination of radiative effects of water clouds. The exclusion of radiative effects of water clouds increases tropical rainfall through the strengthened infrared cooling, which is insensitive to the change in carbon dioxide.

  3. 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.

  4. 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.

  5. 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.

  6. A water vapour monitor at Paranal Observatory

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

  7. 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

  8. 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

  9. 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. PMID:16857703

  10. Characteristics of Single/Double-Effect Combination Absorption Refrigerator

    NASA Astrophysics Data System (ADS)

    Kimijima, Shinji; Waragai, Shisei; Uekusa, Tsuneo; Nakao, Masaki; Kawai, Sunao

    In recent years, co-generation system with fuel cell occupies the attention of the world from a standpoint of the environmental protection and the effective utilization of the energy. Since the waste heat of phosphoric acid fuel cell is recovered in two forms of steam (0.6 [MPa]) and hot water (65∼90 [°C]), this type of absorption refrigerator is driven by two heat sources. In this paper, we inquire the result of the experiment intented for this absorption refrigerator the standard cooling capacity of which is 35[kW]. It is recognized that there is a mutual intervention when the supply condition of steam pressure is changed. Also the effects of hot water temperature, cooling water temperature and chilled water temperature for the performance of this absorption refrigerator is clarified. As a result, the effectiveness of using steam and hot water simultaneously in year-round operation is shown. Furthermore, it is clarified that the utilization of the low boiling temperature medium as the heat transfer medium for air-conditioner is effective.

  11. Singling out the double effect – some further comment

    PubMed Central

    Papanikitas, Andrew; Spicer, John

    2015-01-01

    Abstract We comment on a paper published in the same issue of the London Journal of Primary Care. We applaud Bow’s engagement with the ethical issues in a previous LJPC paper but argue that further work is needed to establish the everyday moral concerns of health care workers in primary care. We also suggest that the ethical distinction between advice and medication and devices may be artificial if both have an effect on a patient. PMID:26550038

  12. 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

  13. 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.

  14. [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

  15. Effects of choke-load position on radiation properties in double-choked small horn antennas

    NASA Astrophysics Data System (ADS)

    Miyata, K.; Suzuki, M.

    1983-04-01

    Results of experiments conducted for the purpose of investigating the effects of the choke position on the beam circularity and the crosspolarisation properties in double-choked small horn antennas are presented. It is shown that the value of the maximum crosspolarisation can be suppressed below -37 dB by properly displacing the choke position from the circular waveguide aperture.

  16. 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.

  17. Effect of frequency-doubling pulse Nd:YAG laser on microbial mutation

    NASA Astrophysics Data System (ADS)

    Zhao, Yansheng; Wang, Luyan; Zheng, Heng; Yin, Hongping; Chen, Xiangdong; Tan, Zheng; Wu, Wutong

    1999-09-01

    We are going to report the mutagenic effect of frequency-doubling pulse Nd:YAG laser (532 nm) on microbe. After irradiation with pulse laser, mutants of abscisic acid producing strains and erythromycin producing strains were obtained, one of which could produce 62.1% and 57% more products than control, respectively. In the study of mutagenization of Spirulina platensis caused by pulse laser, we selected a high photosynthetic strains, with improved productivity of protein and exocellular ploysaccharides of 12% and 246%, respectively. The experimental results indicate that frequency-doubling pulse laser (532 nm) is a potential new type of physical mutagenic factor.

  18. Effect of design features on performance of a double-annular ram-induction combustor

    NASA Technical Reports Server (NTRS)

    Schultz, D. F.

    1975-01-01

    An extensive test program was undertaken to determine the effect of many design features such as the size and number of air scoops, and the type of diffuser airflow distribution to use to optimize performance of a double-annular ram-induction combustor of 94 cm outer diameter. Six combustor configurations were tested. It was found that a snouted double annular combustor built with 256 ram-induction air scoops with a combustor open area giving a total pressure loss of 5.0 percent at a diffuser inlet Mach number of 0.25 gave the best overall performance of the configurations tested.

  19. Effect of glucagon on the diagnostic accuracy of double-contrast barium enema examinations.

    PubMed

    Thoeni, R F; Vandeman, F; Wall, S D

    1984-01-01

    The effect of glucagon-induced hypotonicity on the diagnostic accuracy of double-contrast barium enema examinations was determined in 133 consecutive patients in a double-blind crossover study. All patients underwent colonoscopy and served as their own controls by undergoing a double-contrast study after intravenous injection of 1 mg of glucagon and another after intravenous injection of 1 ml of saline placebo, in randomized order. The frequencies of good/excellent hypotonicity and quality of examinations after first doses of glucagon (55.3% and 80.8%) were not significantly different from the frequencies of good/excellent results after first doses of saline (51.3% and 86.5%). The sensitivity was 72.6% after glucagon and 64.5% after placebo; the specificity was 88.7% after glucagon and 77.9% after placebo; and the respective accuracies were 81.2% and 71.9%. These percentages should be used only to compare results with and without glucagon and, by study design, do not represent results of a complete double-contrast study. The variation among these percentages was not statistically significant, but diverticulitis was more accurately diagnosed after glucagon. It was concluded that glucagon does not significantly improve the sensitivity and specificity of the double-contrast barium enema examination and should be used only in selected instances. PMID:6606942

  20. 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.

  1. 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.

  2. Optical and mechanical properties of vacuum evaporated vapour chopped polyaniline thin film

    NASA Astrophysics Data System (ADS)

    Yadav, J. B.; Puri, R. K.; Puri, V.

    2007-08-01

    The paper reports the effect of chopping the vapour flow on properties of vacuum evaporated polyaniline thin films synthesized by aqueous polymerization pathway. The chopper was a metallic vane of V-shaped cut out placed between the substrate and boat in the path of evaporated vapour. It interrupted the flow of vapour at a constant rate. Fourier Transform Infra-red (FTIR) studies indicated that the vacuum evaporated films are more in reduced form and contain short chain oligomers. Improved adhesion and reduced intrinsic stress of polyaniline thin film due to chopping are obtained. Higher transmittance and lower refractive index films resulted due to the process of chopping as compared to the deposited films. Chopping also produces smoother surface morphology.

  3. 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

  4. Simulation of the isotopic composition of stratospheric water vapour - Part 2: Investigation of HDO / H2O variations

    NASA Astrophysics Data System (ADS)

    Eichinger, R.; Jöckel, P.; Lossow, S.

    2015-06-01

    Studying the isotopic composition of water vapour in the lower stratosphere can reveal the driving mechanisms of changes in the stratospheric water vapour budget and therefore help to explain the trends and variations of stratospheric water vapour during recent decades. We equipped a global chemistry climate model with a description of the water isotopologue HDO, comprising its physical and chemical fractionation effects throughout the hydrological cycle. We use this model to improve our understanding of the processes which determine the patterns in the stratospheric water isotope composition and in the water vapour budget itself. The link between the water vapour budget and its isotopic composition in the tropical stratosphere is presented through their correlation in a simulated 21-year time series. The two quantities depend on the same processes; however, they are influenced with different strengths. A sensitivity experiment shows that fractionation effects during the oxidation of methane have a damping effect on the stratospheric tape recorder signal in the water isotope ratio. Moreover, the chemically produced high water isotope ratios overshadow the tape recorder in the upper stratosphere. Investigating the origin of the boreal-summer signal of isotopically enriched water vapour reveals that in-mixing of old stratospheric air from the extratropics and the intrusion of tropospheric water vapour into the stratosphere complement each other in order to create the stratospheric isotope ratio tape recorder signal. For this, the effect of ice lofting in monsoon systems is shown to play a crucial role. Furthermore, we describe a possible pathway of isotopically enriched water vapour through the tropopause into the tropical stratosphere.

  5. Precipitable water vapour over La Silla Paranal Observatory

    NASA Astrophysics Data System (ADS)

    Kerber, F.

    2011-11-01

    In support of characterization of potential sites for the European Extremely Large Telescope (E-ELT) the European Southern Observatory (ESO), the Institute for Space Imaging Science (ISIS) and the astrometeorology group of the Universidad Valparaiso have jointly established an improved understanding of atmospheric precipitable water vapour (PWV) above ESO's La Silla Paranal Observatory. To this end we have statistically analysed 8 years worth of high resolution spectra taken with VLT-UVES to reconstruct the PWV history above Paranal. For Silla data from FEROS covering about 5 years have been used. In the analysis a radiative transfer model of Earth's atmosphere (BTRAM) developed by ISIS has been employed. In order to better understand the systematics involved three dedicated campaigns were conducted in May, August and November 2009 during which several instruments and methods were validated with respect to balloon-borne radiosondes, the established standard in atmospheric research. After correction for systematic effects a median PWV of 2.4 mm is found for Paranal whereas the value for La Silla is 3.7 mm. The results of the study were submitted to the E-ELT site selection advisory committee late in 2009. Valuable lessons for observatory operations have been learned and ESO is planning to permanently deploy a water vapour monitor on Paranal as part of the VISIR upgrade project. For the E-ELT we find that a stand-alone high time resolution PWV monitor will be essential for optimizing the scientific output.

  6. Thermodynamic modelling of a double-effect LiBr-H2O absorption refrigeration cycle

    NASA Astrophysics Data System (ADS)

    Iranmanesh, A.; Mehrabian, M. A.

    2012-12-01

    The goal of this paper is to estimate the conductance of components required to achieve the approach temperatures, and gain insights into a double-effect absorption chiller using LiBr-H2O solution as the working fluid. An in-house computer program is developed to simulate the cycle. Conductance of all components is evaluated based on the approach temperatures assumed as input parameters. The effect of input data on the cycle performance and the exergetic efficiency are investigated.

  7. The Water Vapour Radiometer at Effelsberg

    NASA Astrophysics Data System (ADS)

    Roy, A. L.; Teuber, U.; Keller, R.

    We have installed a scanning 18 GHz to 26 GHz water vapour radiometer on the focus cabin of the Effelsberg 100 m telescope for tropospheric phase, delay and opacity correction during high-frequency VLBI observations. It is based on the design by Tahmoush & Rogers (2000) but with noise injection for calibration, weather-proof housing, and temperature stabilization. The radiometer is delivering data into an archive since July 2003, from which they are available for download. The data will be delivered automatically to PIs of EVN experiments in a calibration table attached by the EVN calibration pipeline. This paper describes the radiometer and its performance.

  8. 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

  9. 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

  10. 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.

  11. Remote Sensing of Atmospheric Water Vapour by Pressure Modulation Radiometry.

    NASA Astrophysics Data System (ADS)

    Davis, G. R.

    1987-09-01

    Available from UMI in association with The British Library. Requires signed TDF. The Stratospheric and Mesospheric Sounder (SAMS) was a limb-sounding satellite experiment which used the technique of pressure modulation radiometry to measure the temperature and constituent distributions in the middle atmosphere. Two channels in the SAMS were devoted to the detection of water vapour, but the analysis of these data have produced unexpectedly high mixing ratios in the region of the stratopause. This thesis describes an attempt to resolve the discrepancy between theory and experiment by a laboratory investigation of the pressure modulation of water vapour. The central role of water vapour in the physics and chemistry of the middle atmosphere and previous attempts to measure its abundance are discussed. It is shown that the intercomparison of humidity sensing instruments has not produced a consensus and that the accuracy of the reported measurements is therefore in question. The SAMS water vapour channels are described and the need is shown for a laboratory transmission experiment. The pressure modulation technique is described in chapter 2 and a mathematical formulation is given. The constraints due to contaminant signals and harmonic contributions are considered and the use of the square wave chopping approximation in the interpretation of the measurements is discussed. In chapter 3, the spectroscopy of the H _2O rotation band is considered and it is shown that there are large uncertainties in most aspects of the problem due to the lack of spectroscopic measurements in this spectral region. In particular, the shapes of the collision broadened line wings under both self and foreign broadened conditions are poorly determined, a situation which is especially problematic for pressure modulation radiometry. The pressure modulation of water vapour is investigated in chapter 4 and it is shown by direct measurement of the pressure cycle that the linear model used by previous

  12. 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

  13. 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

  14. Canopy-scale kinetic fractionation of atmospheric carbon dioxide and water vapour isotopes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The isotopic fluxes of carbon dioxide (CO2) and water vapour (H2O) between the atmosphere and terrestrial plants provide powerful constraints on carbon sequestration on land 1-2, changes in vegetation cover 3 and the Earth’s Dole effect 4. Past studies, relying mainly on leaf-scale observations, hav...

  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. PMID:26383233

  16. 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.

  17. The Kondo Effect and Controlled Spin Entanglement in Coupled Double-Quantum-Dots

    NASA Astrophysics Data System (ADS)

    Chang, Albert M.

    2005-07-01

    Semiconductor double-quantum dots represent an ideal system for studying the novel spin physics of localized spins. On each quantum dot when the number of electrons is odd and the net spin is 1/2, a strong coupling of this localized spin to conducting electrons in the leads gives rise to Kondo correlation. On the other hand, in the coupled double-quantum-dot if the inter-dot antiferromagnetic interaction is strong, the two spins can form a correlated spin-singlet state, quenching the Kondo effect. This competition between Kondo and antiferromagnetic correlation is studied in a controlled manner by tuning the inter-dot tunnel coupling. Increasing the inter-dot tunneling, we observe a continuous transition from a single-peaked to a double-peaked Kondo resonance in the differential conductance. On the double-peaked side, the differential conductance becomes suppressed at zero source-drain bias. The observed strong suppression of the differential conductance at zero bias provides direct evidence signaling the formation of an entangled spin-singlet state. This evidence for entanglement and the tunability of our devices bode well for quantum computation applications.

  18. 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.

  19. 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).

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Effect of interdiffusion on nonlinear intraband light absorption in Gaussian-shaped double quantum rings

    NASA Astrophysics Data System (ADS)

    Aziz-Aghchegala, V. L.; Mughnetsyan, V. N.; Kirakosyan, A. A.

    2015-06-01

    The effect of interdiffusion on electronic states and nonlinear light absorption in Gaussian-shaped double quantum rings is studied. The confining potential, electron energy spectrum, wave functions and absorption coefficient are obtained for different values of diffusion parameter. The effect of the variation of Gaussian parameters is considered as well. The selection rules for the intraband transitions in the cases of the light polarization parallel and perpendicular to the quantum rings' axis are obtained. It is shown that the interdiffusion can be used as an effective tool for the purposeful manipulation of the electric and optical properties of the considered structure.

  8. 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

  9. 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.}

  10. 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.

  11. 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

  12. Inner-shell electron effects in strong-field double ionization of Xe

    NASA Astrophysics Data System (ADS)

    Yuan, Zongqiang; Ye, Difa; Liu, Jie; Fu, Libin

    2016-06-01

    We investigate theoretically the inner-shell electron effects in strong-field double ionization of Xe by a comparative study with two different three-dimensional semiclassical models, i.e., the widely used helium-like model and an improved Green-Sellin-Zachor (GSZ) model. The enhanced double-ionization signals through sequential ionization and recollision-induced excitation with subsequent field ionization are identified as two origins of the nonstructured pattern in the correlated electron momentum spectrum observed in a recent experiment [Phys. Rev. Lett. 113, 103001 (2014), 10.1103/PhysRevLett.113.103001]. The relationship between these enhancements and the inner-shell electrons is revealed by back analysis of the classical trajectories.

  13. Modelling the budget of middle atmospheric water vapour isotopes

    NASA Astrophysics Data System (ADS)

    Zahn, A.; Franz, P.; Bechtel, C.; Groo, J.-U.; Rckmann, T.

    2006-06-01

    A one-dimensional chemistry model is applied to study the stable hydrogen (D) and stable oxygen isotope (17O, 18O) composition of water vapour in stratosphere and mesosphere. In the troposphere, this isotope composition is determined by "physical'' fractionation effects, that are phase changes (e.g. during cloud formation), diffusion processes (e.g. during evaporation from the ocean), and mixing of air masses. Due to these processes water vapour entering the stratosphere first shows isotope depletions in D/H relative to ocean water, which are ~5 times of those in 18O/16O, and secondly is mass-dependently fractionated (MDF), i.e. changes in the isotope ratio 17O/16O are ~0.52 times of those of 18O/16O. In contrast, in the stratosphere and mesosphere "chemical'' fractionation mechanisms, that are the production of HO due to the oxidation of methane, re-cycling of H2O via the HOx family, and isotope exchange reactions considerably enhance the isotope ratios in the water vapour imported from the troposphere. The model reasonably predicts overall enhancements of the stable isotope ratios in H2O by up to ~25% for D/H, ~8.5% for 17O/16O, and ~14% for 18O/16O in the mesosphere relative to the tropopause values. The 17O/16O and 18O/16O ratios in H2O are shown to be a measure of the relative fractions of HOx that receive the O atom either from the reservoirs O2 or O3. Throughout the middle atmosphere, MDF O2 is the major donator of oxygen atoms incorporated in OH and HO2 and thus in H2O. In the stratosphere the known mass-independent fractionation (MIF) signal in O3 is in a first step transferred to the NOx family and only in a second step to HOx and H2O. In contrast to CO2, O(1D) only plays a minor role in this MIF transfer. The major uncertainty in our calculation arises from poorly quantified isotope exchange reaction rate coefficients and kinetic isotope fractionation factors.

  14. 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.

  15. Contributions of Organic Vapours to Atmospheric Nanoparticle Growth

    NASA Astrophysics Data System (ADS)

    Wang, L.; Xu, W.; Khalizov, A. F.; Zhang, R.

    2010-12-01

    Atmospheric aerosol particles alter radiative balance of the earth-atmosphere system, impact the regional and global climate, and pose negative effects on human health. Aerosol nucleation events have been frequently observed under various tropospheric conditions and account for a major fraction of the total aerosol population. Although a number of studies suggest that organics are involved in both new particle formation and their subsequent growth, the fundamental chemical processes responsible for organic vapours’ contribution remain poorly understood. This work will focus on laboratory studies on the role of various organic vapours in sulphuric acid nanoparticles growth. Sulfuric acid nanoparticles of 4-20 nm diameter size are generated from homogeneous binary nucleation of H2SO4 and H2O vapors in a laminar flow reactor. The growth factor of H2SO4 nanoparticles exposed to organics including methyglyoxal, ethanol, 1-butanol, 1-heptanol, 1-decanol, and cis-pinonic acid is measured using a nano-tandem differential mobility analyzer (nano-TDMA). Also studied is the potential synergistic effect in the presence of two or more organic vapours to which sulphuric acid nanoparticles are exposed. The chemical compositions of H2SO4 particles exposed to the organics are analyzed by a thermal desorption-ion drift-chemical ionization mass spectrometer (TD-ID-CIMS), and the spectroscopic evolution of functional groups in H2SO4 particles of ~40 nm diameter size, deposited on ZnSe crystal and subsequently exposed to organics, is studied using attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FT-IR). The combined techniques are used to elucidate the key factors in controlling atmospheric nanoparticle growth.

  16. 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. PMID:10677667

  17. 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

  18. Effects of the interstrip gap on the efficiency and response of Double Sided Silicon Strip Detectors

    NASA Astrophysics Data System (ADS)

    Torresi, D.; Forneris, J.; Grassi, L.; Acosta, L.; Di Pietro, A.; Figuera, P.; Fisichella, M.; Grilj, V.; Jakic, M.; Lattuada, M.; Mijatovic, T.; Milin, M.; Prepolec, L.; Skukan, N.; Soic, N.; Stanko, D.; Tokic, V.; Uroic, M.; Zadro, M.

    2016-05-01

    In this work the effects of the segmentation of the electrodes of Double Sided Silicon Strip Detectors (DSSSDs) are investigated. In order to characterize the response of the DSSSDs we perform a first experiment by using tandem beams of different energies directly sent on the detector and a second experiment by mean of a proton microbeam. Results show that the effective width of the inter-strip region and the efficiency for full energy detection, varies with both detected energy and bias voltage. The experimental results are qualitatively reproduced by a simplified model based on the Shockley-Ramo-Gunn framework.

  19. 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. PMID:23005771

  20. [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. PMID:22739958

  1. Analysis of atmospheric concentrations of quinones and polycyclic aromatic hydrocarbons in vapour and particulate phases

    NASA Astrophysics Data System (ADS)

    Delgado-Saborit, Juana Maria; Alam, Mohammed S.; Godri Pollitt, Krystal J.; Stark, Christopher; Harrison, Roy M.

    2013-10-01

    Polycyclic aromatic hydrocarbons (PAH) are often measured in studies of atmospheric chemistry or health effects of air pollution, due to their known human carcinogenicity. In recent years, PAH quinone derivatives have also become a focus of interest, primarily because they can contribute to oxidative stress. This work reports concentrations of 17 PAH and 15 quinones measured in air samples collected at a trafficked roadside. Data are presented for four compounds not previously reported in ambient air: 2-methyl-1,4-naphthoquinone, 2,6-di-tert-butyl-1,4-benzoquinone, methyl-1,4-benzoquinone and 2,3-dimethylanthraquinone, and a large vapour phase component is measured, not analysed in most earlier studies. Analyses are reported also for SRM 1649a and 1649b, including many compounds (8 for SRM 1649a and 12 for SRM 1649b) for which concentrations have not previously been reported. This work assesses the vapour/particle phase distribution of PAHs and quinones in relation to their molecular weight, vapour pressure, polarity and Henry's Law constant, finding that both molecular weight and vapour pressure (which are correlated) are good predictors of the partitioning.

  2. 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.

  3. Nano-porous indium oxide transistor sensor for the detection of ethanol vapours at room temperature

    NASA Astrophysics Data System (ADS)

    Seetha, M.; Mangalaraj, D.

    2012-01-01

    Porous indium oxide thin film prepared by the dip coating technique has been used in the construction of a field effect transistor. The coating solution was prepared from indium chloride precursor. The average particle size of the dip coated thin film was found to be 25 nm. Scanning electron microscopic images show the porous nature of the film, and the root mean square roughness of the film calculated using atomic force microscope was 24 nm. A transistor has been constructed by evaporating metal Aluminium as source and drain electrodes on the indium oxide active layer and employing the silicon substrate itself as a gate. The sensor response of the constructed transistor was tested with ethanol, ammonia and acetone vapours. The sensor showed good response to ethanol vapours even at 5-ppm level, and the time for response and recovery of the gas was nearly 1 min. Response to ammonia and acetone was comparatively poor. When the gate voltage was increased from 0 to 300 mV, a considerable increase in the source-drain current was observed. As the temperature of the sensing element increased, response to ethanol vapours also increased. There was nearly a linear variation in the transistor response for 100 ppm of ethanol vapours when the gate voltage was swept from 0 to 300 mV. The sensor response of the transistor increases with the gas concentration. The constructed transistor was found to be selectively sensitive to ethanol; therefore it can be implemented to work as a breath alcohol checker.

  4. 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. PMID:20536766

  5. Effects of double air-cushion biofeedback exercises in a patient with sacroiliac joint pain

    PubMed Central

    Yoo, Won-gyu

    2015-01-01

    [Purpose] We developed a double air-cushion biofeedback device to be used for sacroiliac (SI) joint exercises and investigated the effects of exercising using the device in a patient with SI joint pain. [Subject] A 40-year-old man, who complained of pain in the left posterior iliac crest area and SI joints over a 6-month period participated. [Methods] After a 4-week exercise program using the double air-cushion biofeedback device, the subject was assessed using the Gaenslen, Patrick, posterior shear (POSH), and resisted abduction (REAB) tests. [Results] After performing exercise designed to strengthen subdivisions of the gluteus medius, the subject had no pain in the Gaenslen, Patrick, POSH, or REAB tests of the SI joint. The visual analog scale (VAS) score for pain on palpation of the left posterior iliac crest area decreased to 4/10 from an initial score of 7/10. [Conclusion] Exercises with the double air-cushion biofeedback device improved hip asymmetry, SI joint mobility, and muscle strength. PMID:26696747

  6. 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.

  7. Non-Darcian effects on double-diffusive convection within a porous medium

    SciTech Connect

    Karimi-Fard, M.; Charrier-Mojtabi, M.C.; Vafai, K.

    1997-06-01

    Natural convection in porous media is widely encountered in nature and technological processes. Water movement in geothermal reservoirs, underground spreading of chemical wastes and other pollutants, thermal insulation, and solidification are just a few examples where the thermal natural convection or the combined thermosolutal natural convection in porous media are observed. This work describes a numerical study of double-diffusive natural convection in a square cavity filled with a porous medium. The flow is driven by a combined buoyancy effect due to both temperature and concentration variations. Several different flow models for porous media, such as Darcy flow, Forchheimer`s extension, Brinkman`s extension, and the generalized flow are considered. The coupled equations are solved using a finite volume approach with a projection algorithm for the momentum equation. Non-Darcian effects are analyzed through investigating the average heat and mass transfer rates. This study consists of a global analysis of each model and the comparison between them when the Darcy number varies. This work also focuses on the influence of the Lewis number on the inertial and boundary effects. It is shown that the inertial and boundary effects have a profound effect on the double-diffusive convection.

  8. Effect of surface tension on the onset of convection in a double-diffusive layer

    NASA Technical Reports Server (NTRS)

    Chen, C. F.; Su, T. F.

    1992-01-01

    The effect of surface tension on the stability of a double-diffusive layer is considered using linear stability analysis. The surface tension is assumed to vary linearly with temperature and solute concentration. The eigenvalue problem is solved by the Galerkin method. Results show that the predicted stability boundary based on Marangoni effects alone is completely altered in the presence of buoyancy effects induced by low gravity levels (about 10 exp -5 g). At reduced gravity levels, salt-finger instability may onset in the overstable mode due to the stabilizing effect of surface tension. Fluid properties in terms of the Prandtl and the Lewis numbers have a profound effect on the stability conditions; opposite stability characteristics are found in salt solutions and in molten metals.

  9. 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

  10. Gaviscon Double Action Liquid (antacid & alginate) is more effective than antacid in controlling postprandial esophageal acid exposure in GERD patients; a double-blind crossover study

    PubMed Central

    De Ruigh, Annemijn; Roman, Sabine; Chen, Joan; Pandolfino, John E.; Kahrilas, Peter J.

    2015-01-01

    Background Recent studies have shown that Gaviscon Double Action Liquid (a combination alginate-antacid) administered postprandially co-localizes with the acid pocket, the ‘reservoir’ for postprandial acid reflux. Aim This study compared the effectiveness of Gaviscon Double Action Liquid to an equivalent strength antacid without alginate in controlling postprandial acid reflux in GERD patients. Methods 14 GERD patients undertook two 3.5-hour high-resolution manometry/pH-impedance studies during which they ate a standardized meal. In a double-blinded randomized crossover design they then took Gaviscon or CVS brand antacid, each with ~18 mmol/l acid neutralizing capacity. The primary outcome was distal esophageal acid exposure; secondary outcomes were number of reflux events, proximal extent of reflux, nadir pH of the refluxate, mechanism of reflux, and reflux symptoms scored with a validated instrument. Results 10 patients completed the study. Gaviscon studies had significantly less distal esophageal acid exposure and greater nadir refluxate pH in the 30–150 minute postprandial period than antacid studies. There were no differences in the number of reflux events (acid or weakly acidic) or the number of proximal reflux events (15–17 cm above the LES) with either study medication. Conclusions Gaviscon Double Action Liquid was more effective than an antacid without alginate in controlling postprandial esophageal acid exposure. However, the number and spatial distribution of reflux events within the esophagus were similar. This suggests that Gaviscon main effectiveness related to its co-localization with and displacement/neutralization of the post-prandial acid pocket, rather than preventing reflux. PMID:25041141

  11. Double effect, all over again: the case of Sister Margaret McBride.

    PubMed

    Prusak, Bernard G

    2011-08-01

    As media reports have made widely known, in November 2009, the ethics committee of St. Joseph's Hospital in Phoenix, Arizona, permitted the abortion of an eleven-week-old fetus in order to save the life of its mother. This woman was suffering from acute pulmonary hypertension, which her doctors judged would prove fatal for both her and her previable child. The ethics committee believed abortion to be permitted in this case under the so-called principle of double effect, but Thomas J. Olmsted, the bishop of Phoenix, disagreed with the committee and pronounced its chair, Sister Margaret McBride, excommunicated latae sententiae, "by the very commission of the act." In this article, I take the much discussed Phoenix case as an occasion to subject the principle of double effect to another round of philosophical scrutiny. In particular, I examine the third condition of the principle in its textbook formulation, namely, that the evil effect in question may not be the means to the good effect. My argument, in brief, is that the textbook formulation of the principle does not withstand philosophical scrutiny. Nevertheless, in the end, I do not claim that we should then "do away" with the principle altogether. Instead, we do well to understand it within the context of casuistry, the tradition of moral reasoning from which it issued. PMID:21597907

  12. The double-way effects of naloxone and clonidine on experimental stress analgesia.

    PubMed

    Cristea, A; Negres, S; Joean, D

    1995-01-01

    We have emitted the hypothesis that the double-way effect is possible not only due to the wide range of receptor substrates and receptor subtypes but it can manifest at the heterosynaptic and synaptic cotransmission level as a consequence of the informational unbalance which very low or very high doses of biological signals (in pathological disorders) or of drug signal (agonist or antagonist) can do on physiological balance between both two coupled synaptic systems. To verify this hypothesis we choosed as place of manifesting and observing of the phenomen the informational gearing between the endogenous opioid system as "modulator" and the catecholaminergic systems as "alarm". As drug signals we used naloxone (NALX) and clonidine (CLON). The function studied to reveal the double-way effect was stress analgesia monitored in the classical test of te "hot plate". The experimental stress was induced to the mouse by submitting to forced swimming using the "despair test". In the work are presented the dose-effect curves and inflexion points which mark the changing of the sense of the effect. PMID:8896087

  13. 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.

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

    PubMed

    Dao, Thien; Dantigny, Philippe

    2009-11-15

    A common protocol employed for the preparation of conidia employs flooding a fungal colony grown on semi-solid media under optimum conditions with an aqueous solution. In contrast, conidia produced in a natural environment are usually not hydrated when disseminated in air and can be produced under water stress. In order to simulate the latter conditions, cultures were grown at different water activities and conidia were dry-harvested on the lid by turning the dishes upside-down then gently tapping the bottom of the box. This study aimed at assessing the effect of the preparation of fungal conidia on their inactivation by ethanol vapours. Firstly ethanol vapours (either 0.30 or 0.45 kPa) were applied to conidia obtained from the standardised protocol and to dry-harvested conidia for some species of Penicillium. While all dry-harvested conidia remained viable after 24 h of treatment, about 1.0, 3.5 and 2.5 log(10) reductions were observed for hydrated conidia of Penicillium chrysogenum, Penicillium digitatum and Penicillium italicum respectively. Secondly ethanol vapours (0.67 kPa) were applied to dry-harvested conidia obtained from cultures grown at 0.99 a(w) and at reduced water activities. For all species, the susceptibility to ethanol vapours of conidia obtained at 0.99 a(w) was significantly greater than that of conidia obtained at reduced water activities. Conidia produced in a natural environment under non-optimal conditions would be much more resistant to ethanol vapours than those produced in the laboratory. This phenomenon may be due to a reduced intracellular water activity of dry-harvested conidia. PMID:19762103

  15. Trace vapour detection at room temperature using Raman spectroscopy.

    PubMed

    Chou, Alison; Radi, Babak; Jaatinen, Esa; Juodkazis, Saulius; Fredericks, Peter M

    2014-04-21

    A miniaturized flow-through system consisting of a gold coated silicon substrate based on enhanced Raman spectroscopy has been used to study the detection of vapour from model explosive compounds. The measurements show that the detectability of the vapour molecules at room temperature depends sensitively on the interaction between the molecule and the substrate. The results highlight the capability of a flow system combined with Raman spectroscopy for detecting low vapour pressure compounds with a limit of detection of 0.2 ppb as demonstrated by the detection of bis(2-ethylhexyl)phthalate, a common polymer additive emitted from a commercial polyvinyl chloride (PVC) tubing at room temperature. PMID:24588003

  16. [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

  17. Effect of β on Seismic Vulnerability Curve for RC Bridge Based on Double Damage Criterion

    NASA Astrophysics Data System (ADS)

    Qing-hai, Feng; Wan-cheng, Yuan

    2010-05-01

    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 β is done, which reflects the bridge vulnerability overall from the point of total probability, and in order to reduce the discreteness, large value of β are suggested.

  18. 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.

  19. Effects of polymer sidebranching in double- and single-layer polyfluorene light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Nakazawa, Y. K.; Carter, S. A.; Nothofer, H.-G.; Scherf, U.; Lee, V. Y.; Miller, R. D.; Scott, J. C.

    2002-05-01

    We study how changes in sidebranching in electroluminescent polymers affect the performance of polyfluorene-based light-emitting diodes with and without additional hole transport materials. We observe that light emission and device efficiency are determined more by the position of the exciton recombination zone than by changes in the polymer morphology induced by sidebranching. Consequently, we find that sidebranching mainly controls the relative emission between vibrational energy levels and has a minimal effect on polymer charge transport properties. Light outputs of 10 000 cd/m2 and device efficiencies of 0.85 and 1.8 cd/A are obtained for single- and double-layer devices, respectively.

  20. Excitation-induced Quantum Confined Stark Effect in a Coupled Double Quantum Wells

    NASA Astrophysics Data System (ADS)

    Shin, Y. H.; Park, Y. H.; Kim, Yongmin; Perry, C. H.

    2011-12-01

    We report a photoluminescence detected anticrossing of the energy levels in an undoped asymmetric coupled-double-quantum-well buried in a p-i-n structure. Due to the built-in electric field, the quantum wells are tilted in such a way that the symmetric energy level is higher than that of the antisymmetric one in the conduction band. Keeping the laser excitation energy below the barrier, with increasing laser power, the level anticrossing and the quantum confined Stark effect were observed due to decreasing built-in electric field by the photogenerated electron and hole pairs.

  1. 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.

  2. Improvement of the COP of the LiBr-Water Double-Effect Absorption Cycles

    NASA Astrophysics Data System (ADS)

    Shitara, Atsushi

    Prevention of the global warming has called for a great necessity for energy saving. This applies to the improvement of the COP of absorption chiller-heaters. We started the development of the high efficiency gas-fired double-effect absorption chiller-heater using LiBr-H2O to achieve target performance in short or middle term. To maintain marketability, the volume of the high efficiency machine has been set below the equal to the conventional machine. The absorption cycle technology for improving the COP and the element technology for downsizing the machine is necessary in this development. In this study, the former is investigated. In this report, first of all the target performance has been set at cooling COP of 1.35(on HHV), which is 0.35 higher than the COP of 1.0 for conventional machines in the market. This COP of 1.35 is practically close to the maximum limit achievable by double-effect absorption chiller-heater. Next, the design condition of each element to achieve the target performance and the effect of each mean to improve the COP are investigated. Moreover, as a result of comparing the various flows(series, parallel, reverse)to which the each mean is applied, it has been found the optimum cycle is the parallel flow.

  3. 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.

  4. Antihypertensive effect of Iranian Crataegus curvisepala Lind.: a randomized, double-blind study.

    PubMed

    Asgary, S; Naderi, G H; Sadeghi, M; Kelishadi, R; Amiri, M

    2004-01-01

    The aim of the present study was to investigate the potential antihypertensive effects of extracts of the flavonoid-rich Iranian flower, Crataegus curvisepala Lind., a member of the Rosaceae family. The hydroalcoholic extract of the leaves and flowers were studied in a double-blind, placebo-controlled clinical trial to determine its effects. A total of 92 men and women with primary mild hypertension, aged 40-60 years, were selected and divided randomly into two groups, receiving either hydroalcoholic extract of C. curvisepala Lind. or placebo three times daily for more than 4 months. Blood pressure (BP) was measured each month. Statistical analysis was carried out using Student's t-test. The results obtained showed a significant decrease in both systolic and diastolic BP after 3 months (p < 0.05). C. curvisepala has a time-dependent antihypertensive effect. PMID:15700749

  5. Effects of Wave-Particle Interactions on Double-Hump Distributions of the H + Polar Wind

    NASA Astrophysics Data System (ADS)

    Pierrard, V.; Barghouthi, I. A.

    2006-04-01

    A Monte Carlo simulation is used in order to study the effects of wave-particle interactions (WPI) on H+ distributions in the polar wind outflow. The simulation also considers effects of the gravity, the polarization electric field, the divergence of geomagnetic field lines and H+-O+ Coulomb collisions. The proton velocity distribution function (VDF) and the profiles of its moments (density, bulk velocity, parallel and perpendicular temperatures, heat flux…) are found for different levels of WPI, i.e., for different values of the normalized diffusion rate in the velocity space ( D ⊥). We find that the wave-particle interactions accelerate the polar wind and can have important effects on the double-hump H+ distribution obtained in the transition region between the collision-dominated low altitudes and the collisionless high altitude regions.

  6. Effect Analysis of Design Variables on the Disc in a Double-Eccentric Butterfly Valve

    PubMed Central

    Kim, Da-Eun; Kim, Kuk-Kyeom; Kim, Jun-Oh

    2014-01-01

    We have performed a shape optimization of the disc in an industrial double-eccentric butterfly valve using the effect analysis of design variables to enhance the valve performance. For the optimization, we select three performance quantities such as pressure drop, maximum stress, and mass (weight) as the responses and three dimensions regarding the disc shape as the design variables. Subsequently, we compose a layout of orthogonal array (L16) by performing numerical simulations on the flow and structure using a commercial package, ANSYS v13.0, and then make an effect analysis of the design variables on the responses using the design of experiments. Finally, we formulate a multiobjective function consisting of the three responses and then propose an optimal combination of the design variables to maximize the valve performance. Simulation results show that the disc thickness makes the most significant effect on the performance and the optimal design provides better performance than the initial design. PMID:24883380

  7. Effects of the environment on the electric conductivity of double-stranded DNA molecules.

    PubMed

    Malyshev, A V; Díaz, E; Domínguez-Adame, F; Malyshev, V A

    2009-08-19

    We present a theoretical analysis of the effects of the environment on charge transport in double-stranded synthetic poly(G)-poly(C) DNA molecules attached to two ideal leads. Coupling of the DNA to the environment results in two effects: (i) localization of carrier functions due to static disorder and (ii) phonon-induced scattering of the carriers between the localized states, resulting in hopping conductivity. A nonlinear Pauli master equation for populations of localized states is used to describe the hopping transport and calculate the electric current as a function of the applied bias. We demonstrate that, although the electronic gap in the density of states shrinks as the disorder increases, the voltage gap in the I-V characteristics becomes wider. A simple physical explanation of this effect is provided. PMID:21828599

  8. Determination of the effective thermal diffusivity of nanofluids by the double hot-wire technique

    NASA Astrophysics Data System (ADS)

    Murshed, S. M. S.; Leong, K. C.; Yang, C.

    2006-12-01

    This paper introduces a new transient double hot-wire technique for the direct measurement of the thermal diffusivity of nanofluids. A correlation to be used with the double hot-wire technique to calculate the effective thermal diffusivity of nanofluids is also developed. Several types of nanofluids were prepared by suspending different volume percentages (1-5%) of titanium dioxide (TiO2), aluminium oxide (Al2O3) and aluminium (Al) nanoparticles in ethylene glycol and engine oil. The thermal diffusivities of these nanofluids determined directly by this technique were found to increase substantially with the increased volume fraction of nanoparticles in base fluids. Based on the calibration results obtained for the base fluids, ethylene glycol and engine oil, the measurement error is estimated to be within 1.2%. The measured thermal diffusivities of nanofluids were found to be significantly higher than those calculated from the thermal diffusivity expression (i.e. αeff = keff/(ρ cp)eff) by using the effective thermal conductivities and volumetric specific heats obtained from the conventional hot-wire method and from the volume fraction mixture rule, respectively.

  9. The ABC Effect in the Double-Pionic Fusion to 4He.

    NASA Astrophysics Data System (ADS)

    Pricking, A.

    2010-04-01

    The double-pionic fusion to 4He was measured exclusively and kinematically complete with the WASA 4π detector at COSY for the reactions dd →4Heπ0π0 and dd →4Heπ+π- . The measurements were performed over the full energy region, where the so-called ABC effect was observed previously in inclusive measurements. Whereas the latter exhibit not only a low-mass enhancement - the ABC-effect - in the 4He missing mass spectrum but also a prominent high-mass enhancement, we observe only a very strong low-mass enhancement and no pronounced high mass enhancement. This is in contrast to theoretical predictions based on t-channel ∆∆ excitation. Also the energy dependence of the observed total cross section does not fit to such predictions. Both features, however, agree very well with the observations in the most basic double-pionic fusion process in the isoscalar channel pn → dπ0π0.

  10. Structural design of a double-layered porous hydrogel for effective mass transport

    PubMed Central

    Kim, Hyejeong; Kim, Hyeon Jeong; Huh, Hyung Kyu; Hwang, Hyung Ju; Lee, Sang Joon

    2015-01-01

    Mass transport in porous materials is universal in nature, and its worth attracts great attention in many engineering applications. Plant leaves, which work as natural hydraulic pumps for water uptake, have evolved to have the morphological structure for fast water transport to compensate large water loss by leaf transpiration. In this study, we tried to deduce the advantageous structural features of plant leaves for practical applications. Inspired by the tissue organization of the hydraulic pathways in plant leaves, analogous double-layered porous models were fabricated using agarose hydrogel. Solute transport through the hydrogel models with different thickness ratios of the two layers was experimentally observed. In addition, numerical simulation and theoretical analysis were carried out with varying porosity and thickness ratio to investigate the effect of structural factors on mass transport ability. A simple parametric study was also conducted to examine unveiled relations between structural factors. As a result, the porosity and thickness ratio of the two layers are found to govern the mass transport ability in double-layered porous materials. The hydrogel models with widely dispersed pores at a fixed porosity, i.e., close to a homogeneously porous structure, are mostly turned out to exhibit fast mass transport. The present results would provide a new framework for fundamental design of various porous structures for effective mass transport. PMID:25825619

  11. Ethylene vinylacetate copolymer and nanographite composite as chemical vapour sensor

    NASA Astrophysics Data System (ADS)

    Stepina, Santa; Sakale, Gita; Knite, Maris

    2013-12-01

    Polymer-nanostructured carbon composite as chemical vapour sensor is described, made by the dissolution method of a non-conductive polymer, ethylene vinylacetate copolymer, mixed with conductive nanographite particles (carbon black). Sensor exhibits relative electrical resistance change in chemical vapours, like ethanol and toluene. Since the sensor is relatively cheap, easy to fabricate, it can be used in air quality monitoring and at industries to control hazardous substance concentration in the air, for example, to protect workers from exposure to chemical spills.

  12. Modeling nitrogen and water management effects in a wheat-maize double-cropping system.

    PubMed

    Fang, Q; Ma, L; Yu, Q; Malone, R W; Saseendran, S A; Ahuja, L R

    2008-01-01

    Excessive N and water use in agriculture causes environmental degradation and can potentially jeopardize the sustainability of the system. A field study was conducted from 2000 to 2002 to study the effects of four N treatments (0, 100, 200, and 300 kg N ha(-1) per crop) on a wheat (Triticum aestivum L.) and maize (Zea mays L.) double cropping system under 70 +/- 15% field capacity in the North China Plain (NCP). The root zone water quality model (RZWQM), with the crop estimation through resource and environment synthesis (CERES) plant growth modules incorporated, was evaluated for its simulation of crop production, soil water, and N leaching in the double cropping system. Soil water content, biomass, and grain yield were better simulated with normalized root mean square errors (NRMSE, RMSE divided by mean observed value) from 0.11 to 0.15 than soil NO(3)-N and plant N uptake that had NRMSE from 0.19 to 0.43 across these treatments. The long-term simulation with historical weather data showed that, at 200 kg N ha(-1) per crop application rate, auto-irrigation triggered at 50% of the field capacity and recharged to 60% field capacity in the 0- to 50-cm soil profile were adequate for obtaining acceptable yield levels in this intensified double cropping system. Results also showed potential savings of more than 30% of the current N application rates per crop from 300 to 200 kg N ha(-1), which could reduce about 60% of the N leaching without compromising crop yields. PMID:18948476

  13. 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

  14. 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.

  15. 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.

  16. Study on the Partial Load Characteristics of Double-Effect Absorption Systems

    NASA Astrophysics Data System (ADS)

    Kawakami, Ryuichiro; Fukuchi, Toru; Kaita, Yoshio

    Simulation analysis was carried out to study the partial load characteristics of three different types of double-effect LiBr-water absorption cycle, namely series flow, parallel flow and reverse flow. A computer program was developed for this study to simulate the behavior of the absorption cycles equipped with flow rate control of absorbent, cooling water and chilling water on partial load. The effects of the flow rate control on the coefficient of performance (COP), the maximum temperature and maximum pressure were studied. The results show that not only flow rate control of absorbent is essential for high COP on the partial load, but also flow rate control of cooling water and chilling water is recommendable to save the power of pumping.

  17. Probability of DNA knotting and the effective diameter of the DNA double helix.

    PubMed Central

    Rybenkov, V V; Cozzarelli, N R; Vologodskii, A V

    1993-01-01

    During the random cyclization of long polymer chains, knots of different types are formed. We investigated experimentally the distribution of knot types produced by random cyclization of phage P4 DNA via its long cohesive ends. The simplest knots (trefoils) predominated, but more complex knots were also detected. The fraction of knots greatly diminished with decreasing solution Na+ concentration. By comparing these experimental results with computer simulations of knotting probability, we calculated the effective diameter of the DNA double helix. This important excluded-volume parameter is a measure of the electrostatic repulsion between segments of DNA molecules. The calculated effective DNA diameter is a sensitive function of electrolyte concentration and is several times larger than the geometric diameter in solutions of low monovalent cation concentration. Images Fig. 1 PMID:8506378

  18. 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.

  19. 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

  20. 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.

  1. Redefining electrical double layer thickness in narrow confinements: Effect of solvent polarization

    NASA Astrophysics Data System (ADS)

    Das, Siddhartha; Chakraborty, Suman; Mitra, Sushanta K.

    2012-05-01

    In this paper we delineate the consequences of field-dependent solvent polarization in the electric double layer (EDL) electrostatic potential distribution, and the effective EDL thickness in narrow nanofluidic confinements with thick (or overlapping) EDLs. The EDL, formed at the interface between a charged substrate and an electrolyte solution, induces a large electric field spanning across few nanometer distances from the interface. As a result, a polar solvent like water gets polarized, making its relative permittivity a function of the EDL electric field. This affects the overall EDL electrostatic potential distribution and most importantly, leads to a significant reduction of the effective EDL thickness, with the extent of the reduction being dictated by the value of field independent EDL thickness, strength of the solvent polarization, and the substrate-liquid interfacial electrostatic potential. Such a finding will necessitate redefining the classical EDL thickness, which will be of overwhelming significance in nanofluidic transport.

  2. Spin-flip effects in a parallel-coupled double quantum dot molecule

    NASA Astrophysics Data System (ADS)

    Yang, X. F.; Liu, Y. S.

    2010-07-01

    We investigate theoretically the electronic transport through a parallel-coupled double quantum dot (DQD) molecule attached to metallic electrodes, in which the spin-flip scattering on each quantum dot is considered. Special attention is paid to the effects of the intradot spin-flip processes on the linear conductance by using the equation of motion approach for Green's functions. When a weak spin-flip scattering on each quantum dot is present, the single Fano peak splits into two Fano peaks, and the Breit-Wigner resonance may be suppressed slightly. When the spin-flip scattering strength on each quantum dot becomes strong, the linear conductance spectrum consists of two Breit-Wigner peaks and two Fano peaks due to the quantum interference effects. The positions and shapes of these resonant peaks can be controlled by using the magnetic flux through the quantum device.

  3. Studies of electron correlation effects in multicharged ion atom collisions involving double capture

    SciTech Connect

    Stolterfoht, N.; Sommer, K.; Griffin, D.C.; Havener, C.C.; Huq, M.S.; Phaneuf, R.A.; Swenson, J.K.; Meyer, F.W.

    1988-01-01

    We review measurements of L-Coster Kronig and Auger electron production in slow, multicharged collision systems to study electron correlation effects in the process of double electron capture. The n/sup /minus/3/ law was confirmed for the production of the Coster-Kronig configurations 1s/sup 2/2pn/ell/ (n greater than or equal to 6) in O/sup 6 +/ + He collisions. Enhancement of high angular momentum /ell/ in specific 1s/sup 2/2pn/ell/ configurations was observed by means of high-resolution measurements of the Coster-Kronig lines. The importance of electron correlation effects in couplings of potential energy curves leading to the 1s/sup 2/2pn/ell/ configurations is verified by means of Landau-Zener model calculations. 32 refs., 4 figs.

  4. 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

  5. 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.

  6. Effect of prophylactic antibiotics in acute nonperforated appendicitis: a prospective, randomized, double-blind clinical study.

    PubMed Central

    Busuttil, R W; Davidson, R K; Fine, M; Tompkins, R K

    1981-01-01

    A prospective, randomized, double-blind clinical study was performed to determined the efficacy of short-term (24 hr) perioperative antibiotics in preventing septic complications after emergency appendectomy for nonperforated appendicitis. The patients were stratified into three clinical arms: Group I (placebo, n = 45), Group II (cefamandole, n = 46) and Group III (cefamandole plus carbenicillin, n = 45). The three groups of patients were similar in regard to age, sex, duration of operation and pathologic classification of the appendix. The overall incidence of infection in the study was 5.1%. The infection rates in Groups II (2.2%) and III (0%) were significantly lower than Group I (placebo) (13.3%), (p less than 0.05). No difference was observed between cefamandole alone and cefamandole plus carbenicillin. Average postoperative hospital days per patient for each group was: Group I - 3.8 days; Group II - 2.9 days; Group III - 3.1 days. Cost analysis of hospitalization including cost of prophylactic antibiotics revealed a $247.99 per patient saving for Group II versus Group I and $95.53 for Group III versus Group I. Systemic prophylactic antibiotics can successfully reduce septic complications after appendectomy for nonperforated appendicitis, and a single drug (cefamandole) directed at the facultative pathogens is as effective as double drug therapy, which includes specific anaerobic coverage. PMID:7025769

  7. Double hysteresis loops and large negative and positive electrocaloric effects in tetragonal ferroelectrics.

    PubMed

    Wu, Hong-Hui; Zhu, Jiaming; Zhang, Tong-Yi

    2015-10-01

    Phase field modelling and thermodynamic analysis are employed to investigate depolarization and compression induced large negative and positive electrocaloric effects (ECEs) in ferroelectric tetragonal crystalline nanoparticles. The results show that double-hysteresis loops of polarization versus electric field dominate at temperatures below the Curie temperature of the ferroelectric material, when the mechanical compression exceeds a critical value. In addition to the mechanism of pseudo-first-order phase transition (PFOPT), the double-hysteresis loops are also caused by the abrupt rise of macroscopic polarization from the abc phase to the c phase or the sudden fall of macroscopic polarization from the c phase to the abc phase when the temperature increases. This phenomenon is called the electric-field-induced-pseudo-phase transition (EFIPPT) in the present study. Similar to the two types of PFOPTs, the two types of EFIPPTs cause large negative and positive ECEs, respectively, and give the maximum absolute values of negative and positive adiabatic temperature change (ATC ΔT). The temperature associated with the maximum absolute value of negative ATC ΔT is lower than that associated with the maximum positive ATC ΔT. Both maximum absolute values of ATC ΔTs change with the variation in the magnitude of an applied electric field and depend greatly on the compression intensity. PMID:26307461

  8. 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.

  9. Double-gate junctionless transistor model including short-channel effects

    NASA Astrophysics Data System (ADS)

    Paz, B. C.; Ávila-Herrera, F.; Cerdeira, A.; Pavanello, M. A.

    2015-05-01

    This work presents a physically based model for double-gate junctionless transistors (JLTs), continuous in all operation regimes. To describe short-channel transistors, short-channel effects (SCEs), such as increase of the channel potential due to drain bias, carrier velocity saturation and mobility degradation due to vertical and longitudinal electric fields, are included in a previous model developed for long-channel double-gate JLTs. To validate the model, an analysis is made by using three-dimensional numerical simulations performed in a Sentaurus Device Simulator from Synopsys. Different doping concentrations, channel widths and channel lengths are considered in this work. Besides that, the series resistance influence is numerically included and validated for a wide range of source and drain extensions. In order to check if the SCEs are appropriately described, besides drain current, transconductance and output conductance characteristics, the following parameters are analyzed to demonstrate the good agreement between model and simulation and the SCEs occurrence in this technology: threshold voltage (VTH), subthreshold slope (S) and drain induced barrier lowering.

  10. Crystal Orientation and Temperature Effects on the Double Hysteresis Loop Behavior of a PVDF- g-PS Graft Copolymer

    NASA Astrophysics Data System (ADS)

    Zhu, Lei; Yang, Lianyun; Guan, Fangxiao

    2013-03-01

    In a recent report, double hysteresis loop behavior is observed in a nanoconfined poly(vinylidene fluoride-co-trifluoroethylene-co-chlorotrifluoroethylene)-graft-polystyrene [P(VDF-TrFE-CTFE)- g-PS] copolymer. It is considered that the PS grafts are capable of reducing the compensation polarization and thus the polarization electric field during the reverse poling process, resulting in the double hysteresis loop behavior. In this study, we further investigated crystal orientation and temperature effects on this novel ferroelectric behavior. It is observed that with increasing the orientation factor, the electric displacement-electric field (D-E) loop changes from linear for non-oriented film to double loop for the well-oriented film. With increasing the temperature, the double hysteresis loop is gradually replaced by the single and open loop, which is attributed to the impurity ion migrational loss in the sample. This work is supported by NSF (DMR-0907580).

  11. 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

  12. 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

  13. 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.

  14. Diffusion, swelling and electrical properties of polyisoprene/multiwall carbon nanotube composites in organic solvent vapours.

    PubMed

    Knite, M; Sakale, G; Teteris, V

    2012-10-01

    Polyisoprene/nanostructured carbon composites have been fabricated utilizing multiwall carbon nanotubes and carbon black nanoparticles as electrically conductive filler materials. Simultaneous measurements of (1) absorbed mass of organic solvent vapours (OSV), (2) swelling predicted elongation of sample and (3) electrical resistance changes versus the time of the presence of polyisoprene/multiwall carbon nanotube composites (PCNTC) in the OSV ambience were carried out by an in-house computerized setup. Non-Fickian anomalous diffusion has been found for all PCNTC samples as well as for reference samples of polyisoprene/high structure carbon black composites (PCBC). Obtained results indicate that the filler material content can play a substantial role in vapour diffusion into the composite. An advanced tunneling-percolation model was developed and used for describing of the OSV sensing effect in PCNTC and PCBC. PMID:23421188

  15. 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.

  16. 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.

  17. 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

  18. EVAPORATION: a new vapour pressure estimation methodfor organic molecules including non-additivity and intramolecular interactions

    NASA Astrophysics Data System (ADS)

    Compernolle, S.; Ceulemans, K.; Müller, J.-F.

    2011-09-01

    We present EVAPORATION (Estimation of VApour Pressure of ORganics, Accounting for Temperature, Intramolecular, and Non-additivity effects), a method to predict (subcooled) liquid pure compound vapour pressure p0 of organic molecules that requires only molecular structure as input. The method is applicable to zero-, mono- and polyfunctional molecules. A simple formula to describe log10p0(T) is employed, that takes into account both a wide temperature dependence and the non-additivity of functional groups. In order to match the recent data on functionalised diacids an empirical modification to the method was introduced. Contributions due to carbon skeleton, functional groups, and intramolecular interaction between groups are included. Molecules typically originating from oxidation of biogenic molecules are within the scope of this method: aldehydes, ketones, alcohols, ethers, esters, nitrates, acids, peroxides, hydroperoxides, peroxy acyl nitrates and peracids. Therefore the method is especially suited to describe compounds forming secondary organic aerosol (SOA).

  19. Photocatalytic degradation of toluene vapour using fixed bed multichannel photoreactors equipped with TiO2-coated fabrics.

    PubMed

    Park, O H; Na, H Y

    2008-09-01

    The feasibility of producing TiO2-coated fabric using nonwoven polyester as a photocatalyst support was examined through investigations on (i) changes in the fabric properties after coating with TiO2, (ii) the toluene removal capacity of a multichannel TiO2/fabric/UV reactor in removing the toluene vapour with and without O3 addition, and (iii) the photocatalytic effect of regenerated TiO2. The value and usefulness of a multichannel photoreactor as a main reactor or a supplementary device to improve the efficiency of VOC (volatile organic chemicals) removal in a photoreacting fabric filter, which was originally invented to simultaneously remove fine dust and VOCs, was manifested through investigations of the multichannel effect in the treatment of large volumes of air containing toluene as a sample VOC vapour. The parallel-flow photoreactor was manufactured by fixing TiO2-coated fabrics in parallel along the gas flow and installing UV sources for every channel. Photocatalytic degradation of toluene vapour was investigated with respect to various operational parameters such as reaction time, photocatalyst load, vapour load and number of channels. Toluene vapour was taken as a sample VOC because it is a non-biodegradable toxic organic substance, and the UV/TiO2 process was tested as an alternative process to biofiltration. As a result of this study, it was confirmed that nonwoven polyester can be used as a photocatalyst support, and the multichannel photoreactor, equipped with TiO2-coated fabrics, is a useful device that can economically and efficiently treat a larger vapour load by providing more channels with ozone addition and by arranging the reactor units in series. PMID:18844127

  20. 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

  1. 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

  2. Giant effective mass deviations near the magnetic field-induced minigap in double quantum wells

    SciTech Connect

    Harff, N.E. |; Simmons, J.A.; Lyo, S.K.; Klem, J.F.; Goodnick, S.M.

    1994-09-01

    The authors report major deviations in the electron effective mass m* near the partial energy gap, or minigap, formed in strongly coupled double quantum wells (QWs) by an anticrossing of the two QW dispersion curves. The anticrossing and minigap are induced by an in-plane magnetic field B{sub {parallel}} and give rise to large distortions in the Fermi surface and density of states, including a Van Hove singularity. Sweeping B{sub {parallel}} moves the minigap through the Fermi level, with the upper and lower gap edges producing a sharp maximum and minimum in the low-temperature in-plane conductance, in agreement with theoretical calculations. The temperature dependence of Shubnikov-de Haas (SdH) oscillations appearing in a tilted magnetic field yield a decreased m* {le} 1/3 m*{sub GaAs} near the upper gap edge, and indicate an increase in m* near the lower gap edge.

  3. 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.

  4. Nonlinear magnetodielectric effect in double-perovskite Gd2NiMnO6

    NASA Astrophysics Data System (ADS)

    Oh, S. H.; Choi, H. Y.; Moon, J. Y.; Kim, M. K.; Jo, Y.; Lee, N.; Choi, Y. J.

    2015-11-01

    Magnetic and dielectric properties of the double perovskite Gd2NiMnO6 were investigated. Ferromagnetic order of alternating Ni2+ and Mn4+ spins arises below {{T}\\text{C}}=134 K and an additional order of Gd3+ spins occurs at {{T}\\text{Gd}}=33 K. The formation of short-range ferromagnetic clusters accompanied by a Griffiths phase-like feature below {{T}\\text{G}}=230 K is also suggested. Under the low enough dielectric loss at low temperature regime excluding the influence of the extrinsic effect, a highly nonlinear variation of the dielectric constant was achieved in application of the magnetic fields. Our finding offers an efficient approach to accomplish intrinsically coupled functionality utilizing both magnetic and dielectric quantities.

  5. Spin Brazil-nut effect and its reverse in a rotating double-walled drum.

    PubMed

    Huang, Decai; Lu, Ming; Sen, Surajit; Sun, Min; Feng, Yaodong; Yang, Anna

    2013-04-01

    The segregation of binary mixtures in a filled rotating double-walled drum is explored by simulations. Based on the characteristics of self-gravity and the centrifugal force, we argue that both percolation and buoyancy effects dominate the segregation process. The simulational results show that up to long enough times the segregation state is controlled by the rotational speed, the particle radius and density. At low rotational speeds, the smaller and heavier particles tend to accumulate towards the inner drum wall and the bigger and lighter ones towards the outer drum wall, while the segregation pattern reverses completely at higher rotational speeds. Two typical phase diagrams in the space of the density and radius ratio of bigger particles to smaller particles further confirm the predictions. PMID:23605570

  6. 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.

  7. 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.

  8. 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. PMID:25232893

  9. 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.

  10. 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.

  11. 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

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

    PubMed Central

    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. PMID:24399918

  13. 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.

  14. 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

  15. 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.

  16. The effect of the electrical double layer on the membrane charging process

    NASA Astrophysics Data System (ADS)

    Yu, Miao; Lin, Hao

    2010-11-01

    The electrical charging process of a lipid membrane immersed in electrolytic solutions is of significance to a variety of applications including electroporation and electrodeformation. In these phenomena, the build-up of a potential difference across the membrane (the so-called transmembrane potential, or TMP) induces pore formation and membrane permeabilization (in electroporation) or deformation (in electrodeformation). The classical model treats the membrane as an equivalent capacitor-resistor system which is valid in the zero-thickness electrical double layer (EDL) limit. In this work, the effects of a finite EDL on the charging dynamics are investigated. Starting from the Nernst-Planck equations governing ionic transport, the membrane charging problem is solved in both planar and spherical geometries, and using both analytical and numerical methods. The results demonstrate that the effects of the EDL become more significant as the electrical conductivity of the electrolytic solution decreases, which is a natural consequence of an increased Debye length. The steric effect, which often arises in the limit of large zeta-potentials, is shown to be insignificant for physiological applications. The effective circuit equivalence of the EDL is calculated and validated. The results are discussed in comparison with experimental data on electroporation from the literature.

  17. 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.

  18. Metallic Line Doubling and van hoof Effect in the Spectra of the Variable Star RR Lyrae

    NASA Astrophysics Data System (ADS)

    Sefyani Lakrizi, Fouad; Benhida, Abdelmjid; Gillet, Denis; Mathias, phillipe; de France, Thibault; Benkhaldoun, Zouhair; Lazrek, Mohamed; Daassou, Ahmed

    2015-08-01

    The Oukaïmeden observatory is situated at an altitude of 2700m in the High Atlas mountain range, 78km south of Marrakech 7°52’52’’ west and 31°12’32’’ north. The quality of the sky is considered exceptional, not only for imaging but also for photometry. Indeed, the average measured seeing is of the order of 1 arc second which ensures high quality spectrum recording with a good signal-to-noise ratio. In this communication, we will present our observations of the phenomenon of metallic absorption lines, doubling in the spectra of the variable star RR Lyrae on Fe II (l4923.921 Å), as well as of sodium D lines. In emission, we observed the lines of hydrogen Hα, Hβ and Hγ with a very strong intensity (50 % above the continuum). We also observed the Van Hoof effect which consists of a difference between the radial velocity of the line of the Fe II (λ4923.921 Å) and that of the line Hβ. These observations were carried out with a small spectrograph of approximately 12000 resolution, installed on a 14 inch telescope, during the night of October 12th 2013. This date corresponded to the maximal phase of the Blazhko cycle. The doubling of the lines was interpreted by Schwarzschild on the basis of an atmosphere in two layers. Based on this interpretation we were able to measure the radial velocity of the shock wave deducted from the difference between both red and blue spectral components on the lines Hα of hydrogen, D of the sodium and the Fe II during the doubling of observed lines. The shock wave reached the maximal speed of 160 kms-1 so confirming the hypersonic regime to which atmosphere is submitted during this maximum phase of the Blazhko cycle. We will also present a comparison of our results with those obtained with high resolution spectrographs and thus confirm the validity of our results.

  19. Early analgesic effects of intravenous parecoxib and rectal diclofenac following laparoscopic sterilization: a double-blind, double-dummy randomized controlled trial.

    PubMed

    Ng, Alexander; Swami, Ajay; Smith, Graham; Emembolu, Joe

    2008-01-01

    The aim of this double-blind double-dummy randomized controlled trial was to investigate if there was any difference in analgesia between the maximum recommended doses of rectal diclofenac and iv parecoxib after laparoscopic sterilization. The authors studied 55 ASA I-II patients undergoing gynecological laparoscopy; each patient received either preoperative rectal diclofenac 100 mg and 2 mL of normal saline at induction of anesthesia, or preoperative placebo suppository and 2 mL of parecoxib 40 mg at induction. Pain intensity, sedation, and nausea were measured using a 100-mm visual analogue scale on awakening and at 1, 2, and 3 hour postoperatively. Median (interquartile range) pain intensity at rest on awakening and at 1, 2, and 3 hour postoperatively were 15 (0-40), 37 (10-56), 16 (6-29), and 13 (2-32) mm, respectively, in the parecoxib group, and 3 (0-34), 22 (5-45), 24 (6-37), and 10 (4-21) mm, respectively, in the diclofenac group. There was no significant difference in these scores. Furthermore, there was no significant difference between the two groups in sedation, nausea, rescue analgesia, or rescue antiemetic consumption. Preoperative rectal diclofenac 100 mg and parecoxib 40 mg iv at induction of anesthesia were found to have equianalgesic effects after laparoscopic sterilization. Both drugs appear to be useful after short anaesthetics. PMID:18444448

  20. Stratospheric temperatures in Antarctic winter: Does the 40-year record confirm midlatitude trends in stratospheric water vapour?

    NASA Astrophysics Data System (ADS)

    Roscoe, H. K.; Colwell, S. R.; Shanklin, J. D.

    2003-04-01

    Water vapour is a potent greenhouse gas, and the observed increases in water vapour in the stratosphere act to cool it. Possible changes in stratospheric temperatures are important for future ozone loss because colder temperatures in the edge region of the Antarctic ozone hole act to increase polar stratospheric clouds there, and so delay recovery of the ozone hole. Trends in lower-stratospheric temperature within the core of the Antarctic vortex in winter should be a unique indicator of trends in stratospheric water vapour, because neither changes in CO2 nor in ozone have a large effect on temperature in the lower stratosphere in the dark. Here, measured stratospheric temperatures southward of 70°S in winter are presented and their quality and corrections discussed. The character and magnitude of the long-term changes at Halley (76°S) are similar from 100 to 70 hPa and at 50 hPa, whether corrected for sonde changes or not, and are also similar to those at other Antarctic sites. We found no significant trend in temperatures at Halley between 1960 and 2000, which is inconsistent with the change calculated from the trend in lower-stratospheric water vapour in northern hemisphere midlatitudes between 1960 and 2000. Over the shorter interval between 1980 and 2000 at Halley, the change in temperature was-1.8 ± 0.6 K, in agreement with the change calculated from the trend in stratospheric water vapour in northern hemisphere midlatitudes between 1980 and 2000. The differences between these periods are discussed in terms of: possible fortuitous agreement between 1980 and 2000; the poorer representation and quality of the measurements of stratospheric water vapour between 1960 and 1980; and a possible large variation in the rate of oxidation of CH4 to H2O in the upper stratosphere between 1960 and 1980. Such a variation in oxidation rate was observed by satellite between 1992 and 1999.

  1. The isotope composition of water vapour: A powerful tool to study transport and chemistry of middle atmospheric water vapour

    NASA Astrophysics Data System (ADS)

    Bechtel, Ch.; Zahn, A.

    2003-07-01

    A one-dimensional chemistry model is applied to study the stable hydrogen (D) and stable oxygen isotope (17O, 18O) composition of water vapour in stratosphere and mesosphere. The stable isotope ratios of tropospheric H2O are determined by "physical'' fractionation effects, i.e. phase changes, diffusion processes, and mixing of air masses. Due to these processes water vapour entering the stratosphere (i) is mass-dependently fractionated (MDF), i.e. shifts in the isotope ratio 17O/16O are ~0.52 times of those of 18O/16O and (ii) shows isotope shifts in D/H, which are ~5 times of those in 18O/16O. In stratosphere and mesosphere "chemical'' fractionation, that are the oxidation of methane, re-cycling of H2O via the HOx family, and isotope exchange reactions are shown to considerably enhance the isotope ratios in the imported tropospheric H2O. Enrichments relative to the isotope ratios at the tropopause are used to derive the partitioning of tropospheric (unmodified), re-cycled and in situ generated H2O. The model reasonably predicts overall increases of the stable isotope ratios in H2O by ~23% for D/H, ~8.5% for 17O/16O, and ~14% for 18O/16O. The17O/16O and 18O/16O ratios in H2O are shown to be a measure of the partitioning of HOx that receives its O atom either from the reservoirs O2 or O3. In the entire middle atmosphere, MDF O2 is the major donator of oxygen atoms incorporated in OH and HO2 and thus in H2O. It is demonstrated that in the stratosphere mass-independent fractionation (MIF) in O3 in a first step is transferred to the NOx family and only in a second step to HOx and H2O. In contrast to CO2, O(1D) only plays a minor role in this MIF transfer. The major uncertainty in our calculation arises from the many badly quantified isotope exchange reactions and kinetic isotope fractionation factors.

  2. 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.

  3. 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. PMID:26194994

  4. Method for determining effective nonradiative lifetime and leakage losses in double-heterostructure lasers

    SciTech Connect

    van Opdorp, C.; 't Hooft, G.W.

    1981-06-01

    Carrier losses in double-heterostructure lasers are twofold: (i) nonradiative recombination through killers in the bulk of the active region and at all its boundaries (interfaces and surfaces), and (ii) leakage out of the active region. A simple theory shows the following. In the high-injection regime (papprox. =n) all processes under (i) are directly proportional to n. Consequently their contributions can be lumped together in a single effective nonradiative carrier lifetime tau/sub nr/ ; this tau/sub nr/ is constant (i.e., independent of n) owing to the constant degree of occupation of all killers in the mentioned regime. On the other hand, the leakage losses (ii) are superlinear in n. This provides a well-grounded basis for disentangling the contributions of (i) and (ii) in a given sample. Further, a simple method is presented for accurately determining tau/sub nr/ from data of the external quantum efficiency eta/sub ext/ measured as a function of current I in the spontaneous high-injection regime below the laser threshold. Knowledge of the light-extraction factor (i.e., the ratio of external and internal quantum efficiencies) is essentially unnecessary with this method. However, optionally it can be determined easily from a slight extension of the method. For illustration the method of determining tau/sub nr/, which is also applicable to double-hetero LED's, has been applied to some thirty LPE and metal-organic VPE GaAs-(Ga,Al)As lasers of widely varying qualities. The values found vary between 0.8 and 55 ns. From the measured values of tau/sub nr/ it follows that the upper limit for the interface recombination velocity in the best samples is 270 cm/s. For most samples tau/sub nr/ cannot account for all electrical losses at laser threshold. The superlinear excess losses are ascribable to leakage.

  5. Immediate effects of the trunk stabilizing exercise on static balance parameters in double-leg and one-leg stances

    PubMed Central

    Kim, Jwa-jun; Park, Se-yeon

    2016-01-01

    [Purpose] The purpose of this study was to evaluate the immediate effect of stabilizing exercise using the PNF technique on standing balance in one-leg and double-leg stances. [Subjects and Methods] The present study recruited 34 healthy participants from a local university. The Participants performed four balance tests (double-leg stance with and without vision, one-leg stance with and without vision), before and after exercise. The exercise consisted of exercises performed using PNF techniques (stabilizing reversal and rhythmic stabilization), which were applied to facilitate trunk musculature. To examine balance ability, total displacement of the center of pressure was measured during balance tests. [Results] The total anterior–posterior center of pressure displacement was significantly reduced after applying rhythmic stabilization compared before exercise regardless of the balance test conditions. [Conclusion] The present results suggest that trunk stability exercise using rhythmic stabilization could effectively enhance balance ability under one-leg and double-leg conditions. PMID:27390392

  6. Insight from ozone and water vapour on transport in the tropical tropopause layer (TTL)

    NASA Astrophysics Data System (ADS)

    Ploeger, F.; Fueglistaler, S.; Grooß, J.-U.; Günther, G.; Konopka, P.; Liu, Y. S.; Müller, R.; Ravegnani, F.; Schiller, C.; Ulanovski, A.; Riese, M.

    2011-01-01

    We explore the potential of ozone observations to constrain transport processes in the tropical tropopause layer (TTL), and contrast it with insights that can be obtained from water vapour. Global fields from Halogen Occultation Experiment (HALOE) and in-situ observations are predicted using a backtrajectory approach that captures advection, instantaneous freeze-drying and photolytical ozone production. Two different representations of transport (kinematic and diabatic 3-month backtrajectories based on ERA-Interim data) are used to evaluate the sensitivity to differences in transport. Results show that mean profiles and seasonality of both tracers can be reasonably reconstructed. Water vapour predictions are similar for both transport representations, but predictions for ozone are systematically higher for kinematic transport. Compared to global HALOE observations, the diabatic model prediction underestimates the vertical ozone gradient. Comparison of the kinematic prediction with observations obtained during the tropical SCOUT-O3 campaign shows a large high bias above 390 K potential temperature. We show that ozone predictions and vertical dispersion of the trajectories are highly correlated, rendering ozone an interesting tracer for aspects of transport to which water vapour is not sensitive. We show that dispersion and mean upwelling have similar effects on ozone profiles, with slower upwelling and larger dispersion both leading to higher ozone concentrations. Analyses of tropical upwelling based on mean transport characteristics, and model validation have to take into account this ambiguity between tropical ozone production and in-mixing from the stratosphere. In turn, ozone provides constraints on transport in the TTL and lower stratosphere that cannot be obtained from water vapour.

  7. Acute effects of waterpipe tobacco smoking: a double-blind, placebo-control study

    PubMed Central

    Blank, Melissa D.; Cobb, Caroline O.; Kilgalen, Barbara; Austin, Janet; Weaver, Michael F.; Shihadeh, Alan; Eissenberg, Thomas

    2011-01-01

    Background Waterpipe tobacco smoking usually involves heating flavored tobacco with charcoal and inhaling the resulting smoke after it has passed through water. Waterpipe tobacco smoking increases heart rate and produces subjective effects similar to those reported by cigarette smokers. These responses are thought to be nicotine-mediated, though no placebo-control studies exist. Accordingly, this double-blind, placebo-control study compared the acute physiological and subjective effects of waterpipe tobacco smoking to those produced when participants used a waterpipe to smoke a flavor-matched, tobacco-free preparation. Methods Occasional waterpipe tobacco smokers (N=37; 2–5 monthly smoking episodes for ≥ 6 months) completed two double-blind, counterbalanced sessions that differed by product: preferred brand/flavor of waterpipe tobacco or flavor-matched, tobacco-free preparation. For each 45-minute, ad lib smoking episode blood and expired air CO were sampled, cardiovascular and respiratory response were measured, and subjective response was assessed. Results Waterpipe tobacco smoking significantly increased mean (±SEM) plasma nicotine concentration (3.6±0.7 ng/ml) and heart rate (8.6±1.4 bpm) while placebo did not (0.1±0.0 ng/ml; 1.3±0.9 bpm). For carboxyhemoglobin (COHb) and expired air CO, significant increases were observed for tobacco (3.8±0.4%; 27.9±2.6 ppm) and for placebo (3.9±0.4%; 27.7±3.3 ppm) with no differences across condition. Independent of condition, symptoms of nicotine/tobacco abstinence (e.g., “urges to smoke”, “anxious”) were reduced and direct effects (e.g., “dizzy”, “satisfy”) increased. Discussion These results from the first placebo-control study of waterpipe tobacco smoking demonstrate that waterpipe-induced heart rate increases are almost certainly mediated by nicotine though the subjective effects observed in these occasional smokers were not. PMID:21277706

  8. Gate induced superconductivity in layered material based electronic double layer field effect transistors

    NASA Astrophysics Data System (ADS)

    Ye, J. T.; Inoue, S.; Kobayashi, K.; Kasahara, Y.; Yuan, H. T.; Shimotani, H.; Iwasa, Y.

    2010-12-01

    Applying the principle of field effect transistor to layered materials provides new opportunities to manipulate their electronic properties for interesting sciences and applications. Novel gate dielectrics like electronic double layer (EDL) formed by ionic liquids are demonstrated to achieve an electrostatic surface charge accumulation on the order of 1014 cm-2. To realize electric field-induced superconductivity, we chose a layered compound: ZrNCl, which is known to be superconducting by introducing electrons through intercalation of alkali metals into the van der Waals gaps. A ZrNCl-based EDL transistor was micro fabricated on a thin ZrNCl single crystal made by mechanical micro-cleavage. Accumulating charges using EDL gate dielectrics onto the channel surface of ZrNCl shows effective field effect modulation of its electronic properties. Sheet resistance of ZrNCl EDL transistor is reduced by applying a gate voltage from 0 to 4.5 V. Temperature dependence of sheet resistance showed clear evidence of metal-insulator transition upon gating, observed at a gate voltage higher than 3.5 V. Furthermore, gate-induced superconductivity took place after metal-insulator transition when the transistor is cooled down to about 15 K.

  9. Effects of dehydroepiandrosterone supplementation during stressful military training: a randomized, controlled, double-blind field study.

    PubMed

    Taylor, Marcus K; Padilla, Genieleah A; Stanfill, Katherine E; Markham, Amanda E; Khosravi, Jasmine Y; Ward, Michael D Dial; Koehler, Matthew M

    2012-01-01

    Dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS) are anabolic prehormones involved in the synthesis of testosterone. Both have been shown to exert neuroprotective effects during stress. In this randomized, controlled, double-blind field study, we examined the effects of a 12-day DHEA regimen on stress indices in military men undergoing survival training. Forty-eight men were randomized to either a DHEA treatment group or placebo control group. The treatment group received 50 mg of oral DHEA supplementation daily for 5 days during classroom training followed by 7 days of 75 mg during stressful field operations. Control subjects received identical placebo pills. Salivary assays (DHEA[S], testosterone, and cortisol) were conducted at four time points: distal pre-stress (T1), proximal pre-stress (T2), mock-captivity stress (T3), and 24 h recovery (T4). Subjective distress was also assessed at T1, T3, and T4. As expected, DHEA treatment resulted in higher salivary concentrations of DHEA and DHEAS during daily living, mock-captivity stress, and recovery. Similar patterns were observed for salivary markers of anabolic balance: DHEA/cortisol, DHEAS/cortisol, and testosterone/cortisol concentration ratios. Despite notable time effects, no group differences emerged for subjective distress. A brief, low dose DHEA regimen yielded large increases in salivary DHEA(S) concentrations and enhanced anabolic balance throughout sustained military stress. These physiological changes did not extrapolate to subjective distress. PMID:21790446

  10. Removal of BTEX vapours from waste gas streams using silica aerogels of different hydrophobicity.

    PubMed

    Standeker, Suzana; Novak, Zoran; Knez, Zeljko

    2009-06-15

    Silica aerogels are alternative adsorbents to activated carbon (AC) for the removal and the recovery of organic vapours from gas streams. The adsorption capacity measurements of different silica aerogels were done by mini-column method. Continuous adsorption measurements show that silica aerogels are excellent adsorbents of BTEX vapours from waste gas stream. Compared to the most used adsorbents, such as AC and silica gel, aerogels exhibit capacities which enormously exceed that of both commonly used adsorbents. By increasing the degree of hydrophobicity, aerogels become less effective, but they do not adsorb water vapour from gas stream. Silica monolith aerogels with different degrees of hydrophobicity by incorporating methyltrimethoxysilane (MTMS) or trimethylethoxysilane (TMES) in standard sol-gel synthesis were prepared. Excellent properties of aerogels, obtained with the sol-gel synthesis, were preserved with supercritical drying with CO(2). The degree of hydrophobicity of the aerogels was tested by measuring the contact angle (theta) of a water droplet with the aerogel surface. The aerogels were also characterised by FTIR, nitrogen sorption and DSC/TG measurements. PMID:19095355

  11. 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

  12. Cost-Effectiveness between Double and Single Fecal Immunochemical Test(s) in a Mass Colorectal Cancer Screening

    PubMed Central

    Cai, Shan-Rong; Zhu, Hong-Hong; Huang, Yan-Qin; Li, Qi-Long; Ma, Xin-Yuan; Zhang, Su-Zhan; Zheng, Shu

    2016-01-01

    This study investigated the cost-effectiveness between double and single Fecal Immunochemical Test(s) (FIT) in a mass CRC screening. A two-stage sequential screening was conducted. FIT was used as a primary screening test and recommended twice by an interval of one week at the first screening stage. We defined the first-time FIT as FIT1 and the second-time FIT as FIT2. If either FIT1 or FIT2 was positive (+), then a colonoscopy was recommended at the second stage. Costs were recorded and analyzed. A total of 24,419 participants completed either FIT1 or FIT2. The detection rate of advanced neoplasm was 19.2% among both FIT1+ and FIT2+, especially high among men with age ≥55 (27.4%). About 15.4% CRC, 18.9% advanced neoplasm, and 29.9% adenoma missed by FIT1 were detected by FIT2 alone. Average cost was $2,935 for double FITs and $2,121 for FIT1 to detect each CRC and $901 for double FITs and $680 for FIT1 to detect each advanced neoplasm. Double FITs are overall more cost-effective, having significantly higher positive and detection rates with an acceptable higher cost, than single FIT. Double FITs should be encouraged for the first screening in a mass CRC screening, especially in economically and medically underserved populations/areas/countries. PMID:27144171

  13. Effects of Weight and Syntactic Priming on the Production of Cantonese Verb-Doubling

    ERIC Educational Resources Information Center

    Francis, Elaine J.; Matthews, Stephen; Wong, Reace Wing Yan; Kwan, Stella Wing Man

    2011-01-01

    Verb-doubling, where a copy of the main verb occurs both before and after the direct object, is a structure commonly used in Chinese in sentences containing a frequency or duration phrase. In Cantonese, verb-doubling is highly optional and therefore problematic for existing syntactic, semantic, and pragmatic accounts of its distribution in…

  14. Frequency of glove perforation and the protective effect of double gloves in gynecological surgery.

    PubMed

    Murta, Eddie F C; Silva, Cléber S; Júnior, Odilon R A

    2003-06-01

    The purposes of this prospective study were to verify the frequency of glove perforation during gynecological operations and to evaluate the efficacy of double gloving in preventing damage to the inner glove. From May 2000 to May 2001, three house staff and 12 residents were asked to place their used gloves in bags labeled with the following information: procedure performed, presence of a recognized glove perforation, and role in operating team (surgeon, first or second assistant, and instrumentalist). All glove sets were tested using the method of water pression. Damaged gloves were excluded from that analysis. In all, 35 and 51 operations were utilized with single and double gloves, respectively. There were 240 single gloves and 792 double gloves tested. Perforation occurred in 10.4% of the single gloves and 9.8% of the outer double gloves. There were no cases of perforation in the inner double gloves. In cases of operating time that lasted more than 2 h, 56% of the surgeries that used single gloves had perforation vs 58.5% of the double gloves. The first assistant had the major risk for glove perforation with the use of single or double gloves. The indicator finger of the non-dominant hand was the major risk for perforation. In conclusion, we recommend double gloving in all gynecological surgery to reduce the risk of contracting blood-borne diseases. PMID:12768294

  15. CO2-fluxing collapses metal mobility in magmatic vapour

    DOE PAGESBeta

    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

  16. A Mechanical System for Dispensing Known Amounts of Insecticidal Vapours*

    PubMed Central

    Jensen, J. A.; Pearce, G. W.; Quarterman, K. D.

    1961-01-01

    The requirements for a self-contained semi-automatic insecticidal vapour dispenser for use in the disinsection of aircraft are presented. A prototype device meeting these requirements is described and data on its performance, using DDVP (O,O-dimethyl-2,2-dichlorovinyl phosphate) as the insecticide, are given. In this system a miniature air compressor forces air through a membrane impregnated with DDVP, and the vapour-laden air exits into the cabin through a tubular distribution system equipped with orifices. The vapour output is governed by the volume and the temperature of the air passing through the membrane, and the system is adaptable to all types of aircraft at present in use or projected for the near future. The system can also be adapted for use in the disinsection of other closed or semi-closed spaces. PMID:13789905

  17. Adsorption of n-alkane vapours at the water surface.

    PubMed

    Biscay, Frédéric; Ghoufi, Aziz; Malfreyt, Patrice

    2011-06-21

    Monte Carlo simulations are reported here to predict the surface tension of the liquid-vapour interface of water upon adsorption of alkane vapours (methane to hexane). A decrease of the surface tension has been established from n-pentane. A correlation has been evidenced between the decrease of the surface tension and the absence of specific arrangement at the water surface for n-pentane and n-hexane. The thermodynamic stability of the adsorption layer and the absence of film for longer alkanes have been checked through the calculation of a potential of mean force. This complements the work recently published [Ghoufi et al., Phys. Chem. Chem. Phys., 2010, 12, 5203] concerning the adsorption of methane at the water surface. The decrease of the surface tension has been interpreted in terms of the degree of hydrogen bonding of water molecules at the liquid-vapour interface upon adsorption. PMID:21584320

  18. 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

  19. 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.

  20. [Establishment of lentivirus-mediated system of double suicide genes and its killing effects on K562 cells].

    PubMed

    Jiang, Yi-Rong; Liu, Chun-Sheng; Chen, Xue-Liang; Ma, Dao-Xin

    2004-02-01

    To establish lentivirus-mediated system of double suicide genes and explore its killing effects on K562 cells, lentivirus transfer vector for double suicide genes was constructed using molecular methods, three plasmids of lentivirus gene transfer vector system were transferred into packaging cell line 293T using lipofectine method, the transfer effect was observed through fluorescence microscopy, the lentivirus particles were observed by means of electron microscopy. High titer of lentivirus was harvested from the supernatant of virus-producing cell culture and concentrated by high-speed centrifugation with Poly-L-Lysine (PLL). The K562 cells were infected with the concentrated supernatant containing the virus with the double suicide genes. Fluorescence microscopy and RT- PCR confirmed the integration and expression of extraneous gene. The cytotoxicity to these transgenic cells treated with 5-FC and GCV was measured by MTT assays. The growth inhibition ratio (GIR) of cells and inhibition concentration 50 (IC(50)) were counted. After administration of GCV and 5-FC, the changes of those cells were observed through scanning electron microscope. The results showed that lentivirus transfer vector with double suicide genes was constructed successfully. The above-mentioned plasmids were effectively transferred into 293T cells. So much green fluorescence was observed through fluorescence microscope. A lot of lentivirus particles were observed through transmission electron microscope. Double suicide genes mediated by lentivirus were stably integrated and expressed in K562 cells after infection with the concentrated virus using fluorescence microscopy and RT-PCR. The GIR of K562 cells using GCV or 5-FC was 48.73% or 50.69% respectively and it was apparently higher than that of untransfected cells (P < 0.01). When using GCV and 5-FC together, the GIR was 87.69%, which was apparently higher than that of group using GCV or 5-FC alone (P < 0.01). In conclusion, lentivirus

  1. 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.

  2. 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.

  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 Central

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

    2014-01-01

    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

  5. Strain effects on the performance of zero-Schottky-barrier double-walled carbon nanotube transistors

    NASA Astrophysics Data System (ADS)

    Wahab, Md. Abdul; Khosru, Quazi D. M.

    2010-08-01

    Schrodinger's equation is solved using recursive Green's function algorithm self-consistently with Poisson's equation to study the transport physics of uniaxial and torsional strained double-walled (DW) carbon nanotube (CNT) field-effect transistors (FETs) and to analyze their performance. The characteristics and performance of proposed DW CNTFET are compared with existing single-walled (SW) CNTFET. The strain has great impact on the I-V characteristics of both SW and DW CNT devices. Tensile and torsional strains improve greatly the off-state current and on/off current ratio of both devices. Compressive strain improves on-state current, but this improvement is comparatively small. The effect of strain on off-state current, on-state current, and on/off current ratio is higher in SW CNTFET. The inverse subthreshold slope of DW CNTFET is better than SW CNTFET. But the variation in inverse subthreshold slope with strain is smaller in DW CNTFET. Unlike SW CNTFET the on-state transconductance of DW CNTFET improves with tensile and torsional strains, and degrades with compressive strain. The on-state cut-off frequency of DW CNTFET also shows opposite behavior to SW CNTFET with strain following on-state transconductance. Concrete Physical description is provided to explain all above changes with strain.

  6. Performance of a double-effect absorption chiller driven by ICPC solar collectors

    SciTech Connect

    Bergquam, J.B.; Duff, W.S.; Brezner, J.M.; Henkel, E.T.; Winston, R.; O'Gallagher, J.; Sethi, P.

    1999-07-01

    This paper presents experimental data and analytical results describing the performance of a 70 kW (20 ton), water-fired, double-effect absorption chiller. The chiller is driven by a 106 m{sup 2} array of integrated compound parabolic concentrator (ICPC) solar collectors. For this project, an existing gas-fired chiller was modified to operate on hot water. The water was heated by an array of 336 evacuated ICPC tubes. Each tube has an effective area of 0.317 m{sup 2}. The chiller and collector array are part of a complete solar HVAC system that provides air conditioning and space heating for a 743 m{sup 2} (8,000 ft{sup 2}) commercial building in Sacramento, CA. The other components of the HVAC system are a high temperature storage tank, a cooling tower, a gas-fired back-up boiler and five 14 kW (4 ton) cooling/heating fan coil units. The experimental data are used to determine; (1) the efficiency of the collectors; (2) the coefficient of performance of the chiller; and (3) the overall energy balance on the system. Computer models have also been developed to predict the performance and to optimize the design and operating characteristics of the HVAC system.

  7. A double-blind study of the effect on hemostasis of nabumetone (Relafen) compared to placebo.

    PubMed

    Jennings, M B; Alfieri, D M; Jules, K T; Lesczczynski, C

    2000-01-01

    A double-blind, placebo-controlled clinical trial comparing the effect on hemostasis of nabumetone (Relafen) to placebo in patients who were about to undergo forefoot surgery was performed. Aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) are reported to inhibit platelet cyclooxygenase activity, resulting in altered platelet function and thus potentially enhanced bleeding. Nabumetone has been reported to have no effect on platelet aggregation and bleeding time in normal volunteers and in patients who have undergone knee arthroscopy. After fulfilling the inclusion criteria and after a 1-week washout period (acetaminophen controlled), 15 patients were enrolled in the nabumetone group and 15 patients were randomized in the placebo group. Hemostatic parameters [prothrombin time (PT), partial thromboplastin time (PTT), and Ivy bleeding time (IBT)] were assessed at baseline, visit 2, visit 3, and final visit. No meaningful differences were observed between treatment groups in any of the measured hemostatic parameters. No significant adverse events were reported. There was no significant change from baseline for PT, PTT, and IBT in the nabumetone group (PT, p < .06; PTT, p < .64; IBT, p < .17) versus the placebo group (PT, p < .61; PTT, p < .63; IBT, p < .25). The lack of bleeding diathesis and significant prolongation of PT, PTT, or IBT in this study suggests that nabumetone in dosages up to 1000 mg/day can be administered safely in the immediate preoperative period to patients undergoing forefoot surgery. PMID:10862388

  8. 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

  9. 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.

  10. Modeling and Control of a Double-effect Absorption Refrigerating Machine

    NASA Astrophysics Data System (ADS)

    Hihara, Eiji; Yamamoto, Yuuji; Saito, Takamoto; Nagaoka, Yoshikazu; Nishiyama, Noriyuki

    For the purpose of impoving the response to cooling load variations and the part load characteristics, the optimal operation of a double-effect absorption refrigerating machine was investigated. The test machine was designed to be able to control energy input and weak solution flow rate continuously. It is composed of a gas-fired high-temperature generator, a separator, a low-temperature generator, an absorber, a condenser, an evaporator, and high- and low-temperature heat exchangers. The working fluid is Lithium Bromide and water solution. The standard output is 80 kW. Based on the experimental data, a simulation model of the static characteristics was developed. The experiments and simulation analysis indicate that there is an optimal weak solution flow rate which maximizes the coefficient of performance under any given cooling load condition. The optimal condition is closely related to the refrigerant steam flow rate flowing from the separator to the high temperature heat exchanger with the medium solution. The heat transfer performance of heat exchangers in the components influences the COP. The change in the overall heat transfer coefficient of absorber has much effect on the COP compared to other components.

  11. The Effect of Intravenous Lidocaine on Trigeminal Neuralgia: A Randomized Double Blind Placebo Controlled Trial

    PubMed Central

    Argyra, Erifili

    2014-01-01

    Trigeminal neuralgia is the most common neuralgia. Its therapeutic approach is challenging as the first line treatment often does not help, or even causes intolerable side effects. The aim of our randomized double blind, placebo controlled, crossover study was to investigate in a prospective way the effect of lidocaine in patients with trigeminal neuralgia. Twenty patients met our inclusion criteria and completed the study. Each patient underwent four weekly sessions, two of which were with lidocaine (5 mgs/kg) and two with placebo infusions administered over 60 minutes. Intravenous lidocaine was superior regarding the reduction of the intensity of pain, the allodynia, and the hyperalgesia compared to placebo. Moreover, contrary to placebo, lidocaine managed to maintain its therapeutic results for the first 24 hours after intravenous infusion. Although, intravenous lidocaine is not a first line treatment, when first line medications fail to help, pain specialists may try it as an add-on treatment. This trial is registered with NCT01955967. PMID:27335883

  12. 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.

  13. 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.

  14. Electrochemical Electron Transfer and Proton-Coupled Electron Transfer: Effects of Double Layer and Ionic Environment on Solvent Reorganization Energies.

    PubMed

    Ghosh, Soumya; Soudackov, Alexander V; Hammes-Schiffer, Sharon

    2016-06-14

    Electron transfer and proton coupled electron transfer (PCET) reactions at electrochemical interfaces play an essential role in a broad range of energy conversion processes. The reorganization energy, which is a measure of the free-energy change associated with solute and solvent rearrangements, is a key quantity for calculating rate constants for these reactions. We present a computational method for including the effects of the double layer and ionic environment of the diffuse layer in calculations of electrochemical solvent reorganization energies. This approach incorporates an accurate electronic charge distribution of the solute within a molecular-shaped cavity in conjunction with a dielectric continuum treatment of the solvent, ions, and electrode using the integral equations formalism polarizable continuum model. The molecule-solvent boundary is treated explicitly, but the effects of the electrode-double layer and double layer-diffuse layer boundaries, as well as the effects of the ionic strength of the solvent, are included through an external Green's function. The calculated total reorganization energies agree well with experimentally measured values for a series of electrochemical systems, and the effects of including both the double layer and ionic environment are found to be very small. This general approach was also extended to electrochemical PCET and produced total reorganization energies in close agreement with experimental values for two experimentally studied PCET systems. PMID:27111050

  15. 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.

  16. 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.

  17. 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.…

  18. 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.

  19. 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.

  20. 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.

  1. Overlapping double potential wells in a single optical microtube cavity with vernier-scale-like tuning effect

    NASA Astrophysics Data System (ADS)

    Madani, A.; Bolaños Quiñones, V. A.; Ma, L. B.; Miao, S. D.; Jorgensen, M. R.; Schmidt, O. G.

    2016-04-01

    Spatially and temporally overlapping double potential wells are realized in a hybrid optical microtube cavity due to the coexistence of an aggregate of luminescent quantum dots embedded in the tube wall and the cone-shaped tube's geometry. The double potential wells produce two independent sets of optical modes with different sets of mode numbers, indicating phase velocity separation for the modes overlapping at the same frequency. The overlapping mode position can be tuned by modifying the tube cavity, where these mode sets shift with different magnitudes, allowing for a vernier-scale-like tuning effect.

  2. 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

  3. Effect of xylitol on cariogenic and beneficial oral streptococci: a randomized, double-blind crossover trial

    PubMed Central

    Bahador, A; Lesan, S; Kashi, N

    2012-01-01

    Background/purpose Although habitual consumption of xylitol reduces cariogenic streptococci levels, its effect on beneficial oral streptococci is less clear. The main aim of the study is to investigate the effect of short-term xylitol consumption on the oral beneficial streptococci level of saliva, Streptococcus sanguinis and S. mitis. Material and Methods Twenty four volunteers with a median age of 23.7 years (range: 20-28) harboring Streptococcus mutans, S. sobrinus, S. sanguinis and S. mitis participated in the randomized, double-blind, cross-over study. The experimental chewing gum (1.5 g/pellet) contained 70% xylitol w/w while the control gum contained 63% sorbitol w/w. Saliva samples were collected before and after two three-week test periods with a four-week washout interval. Colony-forming units (CFU)/ml were enumerated for the estimation of S. mutans levels on Mitis Salivarius-Mutans valinomycin (MS-MUTV), S. sobrinus on Mitis Salivarius-Sobrinus (MS-SOB), S. sanguinis on Modified Medium 10-Sucrose (MM10-S) and S. mitis on Mitis Salivarius Agar with Tellurite (MSAT) media. Results The S. mutans and S. sobrinus counts of the saliva samples decreased significantly (p = 0.01 and p = 0.011, respectively) in the xylitol gum group but not in the sorbitol gum group. The salivary S. sanguinis and S. mitis counts did not decrease in both xylitol and sorbitol gum groups. Conclusions Based on the findings of this study, xylitol consumption reduced S. mutans and S. sobrinus counts in saliva but appeared not to effect numbers of S. sanguinis and S. mitis in saliva. So, habitual consumption of xylitol reduces cariogenic streptococci levels without any effect on beneficial sterptococci for the oral cavity. PMID:22973473

  4. 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. PMID:26586051

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  6. 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

  7. 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

  8. Metabolic and hormonal effects of caffeine: randomized, double-blind, placebo-controlled crossover trial.

    PubMed

    MacKenzie, Todd; Comi, Richard; Sluss, Patrick; Keisari, Ronit; Manwar, Simone; Kim, Janice; Larson, Robin; Baron, John A

    2007-12-01

    In short-term studies, caffeine has been shown to increase insulin levels, reduce insulin sensitivity, and increase cortisol levels. However, epidemiological studies have indicated that long-term consumption of beverages containing caffeine such as coffee and green tea is associated with a reduced risk of type 2 diabetes mellitus. There is a paucity of randomized studies addressing the metabolic and hormonal effects of consuming caffeine over periods of more than 1 day. We evaluated the effect of oral intake of 200 mg of caffeine taken twice a day for 7 days on glucose metabolism, as well as on serum cortisol, dehydroepiandrosterone (DHEA), and androstenedione, and on nighttime salivary melatonin. A double-blind, randomized, placebo-controlled crossover study with periods of 7 days and washouts of 5 days comparing caffeine with placebo capsules was conducted. Participants were 16 healthy adults aged 18 to 22 years with a history of caffeine consumption. Blood samples from each subject were assayed for glucose, insulin, serum cortisol, DHEA, and androstenedione on the eighth day of each period after an overnight fast. Nighttime salivary melatonin was also measured. Insulin levels were significantly higher (by 1.80 microU/mL; 95% confidence interval, 0.33-3.28) after caffeine intake than after placebo. The homeostasis model assessment index of insulin sensitivity was reduced by 35% (95% confidence interval, 7%-62%) by caffeine. There were no differences in glucose, DHEA, androstenedione, and melatonin between treatment periods. This study provides evidence that daily caffeine intake reduces insulin sensitivity; the effect persists for at least a week and is evident up to 12 hours after administration. PMID:17998023

  9. 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

  10. Double dissociation of working memory load effects induced by bilateral parietal modulation

    PubMed Central

    Sandrini, Marco; Fertonani, Anna; Cohen, Leonardo G.; Miniussi, Carlo

    2016-01-01

    Transcranial magnetic stimulation and neuroimaging data have revealed bilateral posterior parietal cortex (PPC) involvement during verbal n-back working memory (WM). In this task as n (i.e., WM load) increases, subjects show poorer behavioral performance as well as greater activation of this brain area. Moreover, there is evidence that a brief period of practice or even increased familiarity with the task can improve WM performance and lead to activation changes in the PPC. The aim of this study was to investigate, using transcranial direct current stimulation (tDCS), the effects on WM load performance induced by different PPC modulation after increased familiarity with the task. After a short practice, we tested verbal WM using an n-back task (1-back vs. 2-back) before and after the application of bilateral tDCS over PPCs (left anodal-right cathodal, left cathodal-right anodal or sham). ANOVA showed a significant interaction between tDCS and task. In the 1-back task, left anodal-right cathodal modulation abolished improvement in reaction times observed in the other two modulation conditions. Conversely, in the 2-back task the same effect was observed after left cathodal-right anodal modulation relative to the other two modulation conditions. This double dissociation demonstrates either a differential engagement of each PPC or changes in the interhemispheric balance of activity across this brain region. Neuroimaging studies show parametric activation of the PPC as difficulty increases, but activation does not switch sides. Thus, our observed effects cannot be attributed to increased task difficulty, the stimuli used, or the response requirements. Rather, we suggest that these findings reflect the use of different processing strategies to perform these two tasks. In conclusion, after increased familiarity with the task, different tDCS modulations lead to changes in a task-related region depending on differences in processing strategies in 1-back vs. 2-back. PMID

  11. Cyclotron effects on double layer ion acceleration from laser-irradiated thin foils

    SciTech Connect

    Sharma, Anamika; Tripathi, V. K.; Liu, C. S.

    2010-01-15

    The effect of an axial magnetic field on laser driven ion acceleration from a thin overdense plasma slab is investigated. The magnetic field modifies the refractive index of the plasma and the axial ponderomotive force. The latter compresses the electrons until the space charge field thus created offsets it. When the foil thickness is just bigger than the length at which this happens, the compressed electrons and a thin ion layer detach from the foil forming a double layer that gets accelerated by the laser radiation pressure force. The optimum thickness of laser foil, DELTA{sub s}, for maximum acceleration is sensitive to the polarization of the laser pulse. For right circular polarization it increases, while for left circular polarization it decreases with the magnetic field. The ion energy gain is sensitive to a{sub 0}{sup 2}omega{sup 2}/DELTA{sub s}omega{sub p}{sup 2} (where a{sub 0} is the laser field strength, omega{sub p} is the plasma frequency, and omega is the laser frequency) and can be tuned by varying the magnetic field.

  12. 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.

  13. The in vitro sustained release profile and antitumor effect of etoposide-layered double hydroxide nanohybrids.

    PubMed

    Qin, Lili; Wang, Mei; Zhu, Rongrong; You, Songhui; Zhou, Ping; Wang, Shilong

    2013-01-01

    Magnesium-aluminum layered double hydroxides intercalated with antitumor drug etoposide (VP16) were prepared for the first time using a two-step procedure. The X-ray powder diffraction data suggested the intercalation of VP16 into layers with the increased basal spacing from 0.84-1.18 nm was successful. Then, it was characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy, thermogravimetry and differential thermal analysis, and transmission electron microscopy. The prepared nanoparticles, VP16-LDH, showed an average diameter of 62.5 nm with a zeta potential of 20.5 mV. Evaluation of the buffering effect of VP16-LDH indicated that the nanohybrids were ideal for administration of the drugs that treat human stomach irritation. The loading amount of intercalated VP16 was 21.94% and possessed a profile of sustained release. The mechanism of VP16-LDH release in the phosphate buffered saline solution at pH 7.4 is likely controlled by the diffusion of VP16 anions from inside to the surface of LDH particles. The in vitro cytotoxicity and antitumor assays indicated that VP16-LDH hybrids were less toxic to GES-1 cells while exhibiting better antitumor efficacy on MKN45 and SGC-7901 cells. These results imply that VP16-LDH is a potential antitumor drug for a broad range of gastric cancer therapeutic applications. PMID:23737669

  14. The in vitro sustained release profile and antitumor effect of etoposide-layered double hydroxide nanohybrids

    PubMed Central

    Qin, Lili; Wang, Mei; Zhu, Rongrong; You, Songhui; Zhou, Ping; Wang, Shilong

    2013-01-01

    Magnesium-aluminum layered double hydroxides intercalated with antitumor drug etoposide (VP16) were prepared for the first time using a two-step procedure. The X-ray powder diffraction data suggested the intercalation of VP16 into layers with the increased basal spacing from 0.84–1.18 nm was successful. Then, it was characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy, thermogravimetry and differential thermal analysis, and transmission electron microscopy. The prepared nanoparticles, VP16-LDH, showed an average diameter of 62.5 nm with a zeta potential of 20.5 mV. Evaluation of the buffering effect of VP16-LDH indicated that the nanohybrids were ideal for administration of the drugs that treat human stomach irritation. The loading amount of intercalated VP16 was 21.94% and possessed a profile of sustained release. The mechanism of VP16-LDH release in the phosphate buffered saline solution at pH 7.4 is likely controlled by the diffusion of VP16 anions from inside to the surface of LDH particles. The in vitro cytotoxicity and antitumor assays indicated that VP16-LDH hybrids were less toxic to GES-1 cells while exhibiting better antitumor efficacy on MKN45 and SGC-7901 cells. These results imply that VP16-LDH is a potential antitumor drug for a broad range of gastric cancer therapeutic applications. PMID:23737669

  15. Electric Double-Layer Effects Induce Separation of Aqueous Metal Ions.

    PubMed

    Ji, Qinghua; An, Xiaoqiang; Liu, Huijuan; Guo, Lin; Qu, Jiuhui

    2015-11-24

    Metal ion separation is crucial to environmental decontamination, chromatography, and metal recovery and recycling. Theoretical studies have suggested that the ion distributions in the electric double-layer (EDL) region depend on the nature of the ions and the characteristics of the charged electrode surface. We believe that rational design of the electrode material and device structure will enable EDL-based devices to be utilized in the separation of aqueous metal ions. On the basis of this concept, we fabricate an EDL separation (EDLS) device based on sandwich-structured N-functionalized graphene sheets (CN-GS) for selective separation of aqueous toxic heavy metal ions. We demonstrate that the EDLS enables randomly distributed soluble ions to form a coordination-driven layer and electrostatic-driven layer in the interfacial region of the CN-GS/solution. Through tuning the surface potential of the CN-GS, the effective separation of heavy metal ions (coordination-driven layer) from alkali or alkaline earth metal ions (electrostatic-driven layer) can be achieved. PMID:26481603

  16. 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.

  17. 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.

  18. 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

  19. 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…

  20. 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…

  1. ESA DUE GlobVapour water vapor products: Validation

    NASA Astrophysics Data System (ADS)

    Schneider, Nadine; Schröder, Marc; Lindstrot, Ramus; Preusker, Rene; Stengel, Martin; ESA DUE GlobVapour Consortium

    2013-05-01

    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/m2 for SSMI+MERIS and 2 kg/m2 for GOME/SCIA/GOME-2) are generally met. For more information, documents and data download follow the link: www.globvapour.info.

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. 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…

  7. 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

  8. Simulation of the isotopic composition of stratospheric water vapour - Part 1: Description and evaluation of the EMAC model

    NASA Astrophysics Data System (ADS)

    Eichinger, R.; Jockel, P.; Brinkop, S.; Werner, M.; Lossow, S.

    2015-05-01

    This modelling study aims at an improved understanding of the processes that determine the water vapour budget in the stratosphere by means of the investigation of water isotope ratios. An additional (and separate from the actual) hydrological cycle has been introduced into the chemistry-climate model EMAC, including the water isotopologues HDO and H218O and their physical fractionation processes. Additionally an explicit computation of the contribution of methane oxidation to H2O and HDO has been incorporated. The model expansions allow detailed analyses of water vapour and its isotope ratio with respect to deuterium throughout the stratosphere and in the transition region to the troposphere. In order to assure the correct representation of the water isotopologues in the model's hydrological cycle, the expanded system has been evaluated in several steps. The physical fractionation effects have been evaluated by comparison of the simulated isotopic composition of precipitation with measurements from a ground-based network (GNIP) and with the results from the isotopologue-enabled general circulation model ECHAM5-wiso. The model's representation of the chemical HDO precursor CH3D in the stratosphere has been confirmed by a comparison with chemical transport models (1-D, CHEM2D) and measurements from radiosonde flights. Finally, the simulated stratospheric HDO and the isotopic composition of water vapour have been evaluated, with respect to retrievals from three different satellite instruments (MIPAS, ACE-FTS, SMR). Discrepancies in stratospheric water vapour isotope ratios between two of the three satellite retrievals can now partly be explained.

  9. Simulation of the isotopic composition of stratospheric water vapour - Part 1: Description and evaluation of the EMAC model

    NASA Astrophysics Data System (ADS)

    Eichinger, R.; Jöckel, P.; Brinkop, S.; Werner, M.; Lossow, S.

    2014-09-01

    This modelling study aims on an improved understanding of the processes, that determine the water vapour budget in the stratosphere by means of the investigation of water isotope ratios. At first, a separate hydrological cycle has been introduced into the chemistry-climate model EMAC, including the water isotopologues HDO and H218O and their physical fractionation processes. Additionally an explicit computation of the contribution of methane oxidation to HDO has been incorporated. The model expansions allow detailed analyses of water vapour and its isotope ratio with respect to deuterium throughout the stratosphere and in the transition region to the troposphere. In order to assure the correct representation of the water isotopologues in the model's hydrological cycle, the expanded system has been evaluated in several steps. The physical fractionation effects have been evaluated by comparison of the simulated isotopic composition of precipitation with measurements from a ground-based network (GNIP) and with the results from the isotopologue-enabled general circulation model ECHAM5-wiso. The model's representation of the chemical HDO precursor CH3D in the stratosphere has been confirmed by a comparison with chemical transport models (CHEM1D, CHEM2D) and measurements from radiosonde flights. Finally, the simulated stratospheric HDO and the isotopic composition of water vapour have been evaluated, with respect to retrievals from three different satellite instruments (MIPAS, ACE-FTS, SMR). Discrepancies in stratospheric water vapour isotope ratios between two of the three satellite retrievals can now partly be explained.

  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. Effects of interferons and double-stranded RNA on human prostate cancer cell apoptosis.

    PubMed

    Tan, Haiyan; Zeng, Chun; Xie, Junbo; Alghamdi, Norah J; Song, Ya; Zhang, Hongbing; Zhou, Aimin; Jin, Di

    2015-11-17

    Prostate cancer is the second most commonly diagnosed cancer among men in the United States. Prostate cancer therapy is severely hampered by lack of response and development of resistance to conventional chemotherapeutic drugs in patients. Therefore, the development and discovery of new drugs have become an urgent clinical need. Interferons (IFNs), a family of pleiotropic cytokines, exert antitumor activities due to their anti-proliferative, immunomodulatory and proapoptotic functions. Here, we report that pretreatment of prostate cancer PC-3 cells with IFNs sensitized these cells to double-stranded RNAs (dsRNAs)-induced apoptosis. The enhancement effect of IFN treatment was dependent on IFN subtypes, in particular, IFN γ. In comparison with IFN α or β, IFN γ treatment remarkably augmented apoptosis in PC-3 cells induced with polyinosinic:polycytidylic acid (poly I:C), a synthesized form of dsRNA. We demonstrated that IFN-signaling was necessary for these effects by using mutant cell lines. Transfection of 2-5A, the activator of RNase L, or silencing of dsRNA-dependent protein kinase R (PKR) by siRNA did not have any significant impact on this event, suggesting that neither RNase L nor PKR was involved in poly I:C/IFN γ-induced apoptosis in the cells. Further investigation of the apoptotic pathway revealed that Bak, a pro-apoptotic member of the Bcl-2family, was synergistically up-regulated by IFN γ and poly I:C, whereas other members of the family were not affected. Knocking down of Bak demonstrated its contribution to poly I:C/IFN γ-induced apoptosis in the cells. We believeour findings will precipitate the design of novel therapeutic strategies for prostate cancer. PMID:26452032

  12. Effects of interferons and double-stranded RNA on human prostate cancer cell apoptosis

    PubMed Central

    Tan, Haiyan; Zeng, Chun; Xie, Junbo; Alghamdi, Norah J.; Song, Ya; Zhang, Hongbing; Zhou, Aimin; Jin, Di

    2015-01-01

    Prostate cancer is the second most commonly diagnosed cancer among men in the United States. Prostate cancer therapy is severely hampered by lack of response and development of resistance to conventional chemotherapeutic drugs in patients. Therefore, the development and discovery of new drugs have become an urgent clinical need. Interferons (IFNs), a family of pleiotropic cytokines, exert antitumor activities due to their anti-proliferative, immunomodulatory and proapoptotic functions. Here, we report that pretreatment of prostate cancer PC-3 cells with IFNs sensitized these cells to double-stranded RNAs (dsRNAs)-induced apoptosis. The enhancement effect of IFN treatment was dependent on IFN subtypes, in particular, IFN γ. In comparison with IFN α or β, IFN γ treatment remarkably augmented apoptosis in PC-3 cells induced with polyinosinic:polycytidylic acid (poly I:C), a synthesized form of dsRNA. We demonstrated that IFN-signaling was necessary for these effects by using mutant cell lines. Transfection of 2–5A, the activator of RNase L, or silencing of dsRNA-dependent protein kinase R (PKR) by siRNA did not have any significant impact on this event, suggesting that neither RNase L nor PKR was involved in poly I:C/IFN γ-induced apoptosis in the cells. Further investigation of the apoptotic pathway revealed that Bak, a pro-apoptotic member of the Bcl-2family, was synergistically up-regulated by IFN γ and poly I:C, whereas other members of the family were not affected. Knocking down of Bak demonstrated its contribution to poly I:C/IFN γ-induced apoptosis in the cells. We believeour findings will precipitate the design of novel therapeutic strategies for prostate cancer. PMID:26452032

  13. 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.

  14. 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

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

    NASA Astrophysics Data System (ADS)

    Lei, Wenwen; McKenzie, David R.

    2015-12-01

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

  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. Non-ideal effect in 4H-SiC bipolar junction transistor with double Gaussian-doped base

    NASA Astrophysics Data System (ADS)

    Yuan, Lei; Zhang, Yu-Ming; Song, Qing-Wen; Tang, Xiao-Yan; Zhang, Yi-Men

    2015-06-01

    The non-ideal effect of 4H-SiC bipolar junction transistor (BJT) with a double Gaussian-doped base is characterized and simulated in this paper. By adding a specific interface model between SiC and SiO2, the simulation results are in good agreement with the experiment data. An obvious early effect is found from the output characteristic. As the temperature rises, the early voltage increases, while the current gain gradually decreases, which is totally different from the scenario of silicon BJT. With the same effective Gummel number in the base region, the double Gaussian-doped base structure can realize higher current gain than the single base BJT due to the built-in electric field, whereas the early effect will be more salient. Besides, the emitter current crowding effect is also analyzed. Due to the low sheet resistance in the first highly-doped base epilayer, the 4H-BJT with a double base has more uniform emitter current density across the base-emitter junction, leading to better thermal stability. Project supported by the National Natural Science Foundation of China (Grant Nos. 60876061 and 61234006), the Natural Science Foundation of Shaanxi Province, China (Grant No. 2013JQ8012), and the Doctoral Fund of the Ministry of Education of China (Grant Nos. 20130203120017 and 20110203110010).

  18. 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.

  19. Effects of double filtration plasmapheresis on nocturnal respiratory function in myasthenic patients.

    PubMed

    Yeh, Jiann-Horng; Lin, Chia-Mo; Chen, Wei-Hung; Chiu, Hou-Chang

    2013-12-01

    Assessment of respiratory function using combined oximetry-cutaneous capnography has never been evaluated in patients with myasthenia gravis (MG). We investigated the effects of double filtration plasmapheresis (DFPP) on respiratory status in 18 MG patients. Results of combined oximetry and transcutaneous capnography, MG scores, and acetylcholine receptor antibody titers before and after DFPP treatment were compared. The respiratory monitoring was performed at three time periods (morning, afternoon, and sleep). Mean MG score was markedly lower after DFPP treatment (5.7) than before treatment (7.9). Before DFPP, the minimum pulse oximetric saturation (SpO2 ) level obtained during the night session was significantly lower (P = 0.0513 and P = 0.0199) than the levels obtained during the two daytime sessions. A similar phenomenon was noted for maximum transcutaneous carbon dioxide tension (PtcCO2 ). After DFPP treatment, the maximum and mean PtcCO2 levels were significantly higher (P = 0.0056) in the morning than in the afternoon. Of all the respiratory function parameters measured, only minimum SpO2 levels obtained during morning sessions before DFP treatment differed significantly from those obtained after DFPP treatment (P = 0.0322). Overall, however, minimum SpO2 levels as well as mean and maximum PtcCO2 levels improved significantly during sleep after DFPP. In conclusion, we found that respiratory function abnormalities were common in myasthenic patients without clinical respiratory symptoms. DFPP treatment resulted in minimal improvement of respiratory parameters. PMID:23865547

  20. H-shaped double graft copolymers: Effect of molecular architecture on morphology

    NASA Astrophysics Data System (ADS)

    Lee, Chin; Gido, Samuel P.; Poulos, Yiannis; Hadjichristidis, Nikos; Tan, Nora Beck; Trevino, Samuel F.; Mays, Jimmy W.

    1997-10-01

    The morphologies formed by block copolymers with a double-graft, H or S2IS2 architecture were investigated using transmission electron microscopy (TEM) and small angle neutron scattering (SANS). Here S and I represent blocks of polystyrene and polyisoprene, respectively. These materials were synthesized using anionic polymerization and chlorosilane linking, and they were characterized using size exclusion chromatography, membrane osmometry, and low-angle laser light scattering. This characterization work confirmed the desired molecular architectures and narrow molecular weight distributions. The results of morphological characterization indicate that one can understand complex grafting architectures by decomposing them into fundamental building blocks, which are taken as the component single graft structures out of which the larger structure is constructed. We propose rules for dividing structures into these components, which we call constituting block copolymers. The morphological behavior of the more complex architecture is approximately equivalent to that of the constituting block copolymer structure. Through the use of the constituting block copolymers we map the experimentally determined morphological behavior of the H architecture onto the morphology diagram calculated by Milner for miktoarm stars [Macromolecules 27, 2333 (1994)]. Mapping the H architecture onto the morphology diagram in this way produces general agreement between experimental results and the model. However, it is found that in the case of the H architecture, as well as in previously published results for I2S and I3S miktoarm star materials, that the morphology diagram slightly overestimates the amount of shift in the order-order transition lines produced by asymmetry in molecular architecture. This overestimation in the theory is attribute to a junction point localization effect which was neglected in Milner's calculation.

  1. Analgesic effect of ceruletide compared with pentazocine in biliary and renal colic: a prospective, controlled, double-blind study.

    PubMed

    Lishner, M; Lang, R; Jutrin, I; De-Paolis, C; Ravid, M

    1985-06-01

    The analgesic effect of ceruletide in biliary and renal colic was evaluated by a randomized, double-blind study in 82 patients. Ceruletide was compared with pentazocine, a well-established analgetic agent. Rapid and effective analgesia was obtained by intramuscular injection of ceruletide 0.5 micrograms/kg in 56 patients with biliary colic. The analgesic effect of ceruletide compared well with pentazocine 0.5 mg/kg im, and was associated with remarkably fewer side effects. In 26 patients with renal colic, ceruletide was significantly inferior to pentazocine. These data support the recommendation of ceruletide as a first-choice analgetic agent for biliary colic. PMID:3891284

  2. Effect of single and double austenitization treatments on the microstructure and mechanical properties of 16Cr-2Ni steel

    SciTech Connect

    Balan, K.P.; Venugopal Reddy, A.; Sarma, D.S.

    1999-06-01

    Double austenitization (DA) treatment is found to yield the best combination of strength and toughness in both low-temperature as well as high-temperature tempered conditions as compared to single austenitization (SA) treatments. Obtaining the advantages of double austenitization (DA) to permit dissolution of alloy carbides without significant grain coarsening was attempted in AISI 431 type martensitic stainless steel. Structure-property correlation after low-temperature tempering (200 C) as well as high-temperature double tempering (650 + 600 C) was carried out for three austenitization treatments through SA at 1000 C, SA at 1070 C, and DA at 1070 + 1000 C. While the increase in strength after DA treatment and low-temperature tempering at 200 C is due to the increased amount of carbon in solution as a result of dissolution of alloy carbides during first austenitization, the increased toughness is attributable to the increased quantity of retained austenite. After double tempering (650 + 600 C), strength and toughness are mainly found to depend on the precipitation and distribution of carbides in the microstructure and the grain size effect.

  3. Chemical vapour etching-based porous silicon and grooving: Application in silicon solar cells processing

    NASA Astrophysics Data System (ADS)

    Ben Rabha, M.; Boujmil, M. F.; Saadoun, M.; Bessaïs, B.

    2005-06-01

    Sponge like porous silicon (PS) was formed by a simple and low cost chemical vapour etching (CVE) method and applied in polycrystalline silicon (mc-Si) solar cells processing. The CVE method consists of exposing Si wafers to HNO3/HF vapours. It was shown that 8 min of HNO3/HF CVE (volume ratio = 1/7) is sufficient to form optimized PS layers on the emitter of mc-Si cells. The CVE-based PS can simultaneously passivate the Si surface and serves as an effective antireflection coating (ARC). As a result, the reflectivity decreases by about 60% of its initial value and the internal quantum efficiency is improved, particularly in the short wavelength region. For acid vapours rich in HNO3 (HNO3/HF >1/4), the CVE method favours the formation of a (NH4)2SiF6 powder, which is highly soluble in water. These findings let us achieve anisotropic grooving that enables to groove mc-Si wafers locally and in depth using an adequate anti-acid mask. The CVE - based grooving technique was used to form buried metallic contacts on the rear and frontal surface of the Si wafer in order to improve the current collection in mc-Si solar cells. No alteration of the spectral response in the long wavelength range was observed in mc-Si cells with rear-buried contacts. Adjustments of theoretical spectral responses to experimental ones show an increase in the effective electron diffusion length (Ln), which was attributed to Al gettering (passivation) at grain boundaries and to the reduction of the effective thickness of the base of the cells.

  4. 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.

  5. 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

  6. 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. PMID:24850953

  7. 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

  8. [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

  9. Rashba spin-orbit coupling effects on the optical properties of double quantum wire under magnetic field

    NASA Astrophysics Data System (ADS)

    Karaaslan, Y.; Gisi, B.; Sakiroglu, S.; Kasapoglu, E.; Sari, H.; Sokmen, I.

    2016-05-01

    We investigate the effects of Rashba spin-orbit interaction on the optical absorption coefficients and refractive index changes associated with transitions between the first two lower-lying electronic levels in double quantum wire. The wire system represented by a symmetric, double quartic-well confinement potential is subjected to a perpendicular magnetic field. The analytical expressions of the linear and third-order nonlinear optical absorption coefficients and refractive index changes are obtained by using the compact-density matrix formalism and iterative scheme. Optical properties are investigated as a function of structural parameter, magnetic field, Rashba spin-orbit interaction and photon energies. Numerical results reveal that competing effects between spin-orbit interaction and magnetic field modify strongly the optical properties and can be altered by these parameters.

  10. Effect of Holding Time Before Solidification on Double-Oxide Film Defects and Mechanical Properties of Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    El-Sayed, Mahmoud Ahmed; Salem, Hanadi A. G.; Kandeil, Abdelrazek Youssef; Griffiths, W. D.

    2011-12-01

    Double-oxide films (bifilms) have been held responsible for the variability in mechanical properties of aluminum castings. It has been suggested that the air entrapped inside a bifilm can react with the surrounding melt, leading to its consumption, which might improve the mechanical properties of the castings. In this work the effect of holding the melt before solidification on the distribution of mechanical properties, and by implication on entrained double oxide films, was investigated for several different aluminum alloys. The Weibull moduli of plate castings were determined under tensile conditions, and their fracture surfaces were examined for evidence of oxide films. The results suggested the occurrence of two competing mechanisms during the holding treatment: (1) the consumption of air inside the bifilms by reaction with the surrounding molten metal that may lead to improvements in mechanical properties and (2) the accompanying diffusion of hydrogen into the bifilms, which would be expected to have a deleterious effect on properties.

  11. Resonance laser-induced ionisation of sodium vapour taking radiative transfer into account

    SciTech Connect

    Kosarev, N I; Shaparev, N Ya

    2006-04-30

    The problem of ionisation of atomic sodium in the field of resonance laser radiation is numerically solved taking radiative transfer into account. Seed electrons are produced due to the mechanism of associative ionisation, then they gain energy in superelastic processes (collisions of the second kind) and initiate the avalanche ionisation of the medium by electron impact. We studied the effect of secondary radiation on the laser pulse propagation upon competition between the ionising and quenching electron collisions with excited atoms, on the kinetics of ionisation-induced vapour bleaching, and the plasma channel expansion in the form of a halo. (interaction of laser radiation with matter)

  12. 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

  13. 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.

  14. 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.

  15. 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

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

    DOE PAGESBeta

    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

  17. 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.

  18. 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.

  19. Conformational effects, molecular orbitals, and reaction activities of bis(phthalocyaninato) lanthanum double-deckers: density functional theory calculations.

    PubMed

    Qi, Dongdong; Zhang, Lijuan; Wan, Liang; Zhang, Yuexing; Bian, Yongzhong; Jiang, Jianzhuang

    2011-08-01

    The conformational effects on the frontier molecular orbital energy and stability for reduced, neutral, and oxidized bis(phthalocyaninato) lanthanum double-deckers have been revealed on the basis of density functional theory calculations. Calculation results indicate that the frontier orbital coupling degree changes along with the molecular conformation of the double-decker compound, first decreasing along with the increase of rotation angle β from 0 to 20° and then increasing along with the increase of rotation angle β from 20 to 45°. In addition, the stability for the three forms of double-decker changes in the same order, but first increasing and then decreasing along with the change of the rotation angle β in the range of 0 to 45° with a rotation energy barrier of (31.3 ± 3.1) kJ mol(-1) at 20°. This reveals that the rotation of the two phthalocyanine rings for the reduced, neutral, and oxidized bis(phthalocyaninato) lanthanum double-deckers are able to occur at room temperature. Nevertheless, the superior coordination reaction activity of the neutral bis(phthalocyaninato) lanthanum double-decker complex over their reduced form in forming sandwich-type tris(phthalocyaninato) lanthanum triple-decker compounds has also been clearly clarified on the basis of comparative calculations on the Fukui function of [La(Pc)(2)] and [La(Pc)(2)](-) using the DFT method. Fukui function analysis reveals the reaction center of the 18-electron-π-conjugated core in the bis(phthalocyaninato) lanthanum double-decker molecule against both electrophilic and radical attack. Nevertheless, the larger global chemical softness (S) for the neutral [La(Pc)(2)] than the reduced form [La(Pc)(2)](-) indicates the higher reaction activity of the former form over the latter one. This explains well the experimental findings that only the neutral instead of the reduced form of bis(tetrapyrrole) rare earth double-decker complexes, containing at least one phthalocyanine ligand, could be

  20. A new test method for measuring the water vapour permeability of fabrics

    NASA Astrophysics Data System (ADS)

    Huang, Jianhua; Qian, Xiaoming

    2007-09-01

    The water vapour permeability of textile fabrics is a critical determinant of wearer comfort. Existing test methods are either time consuming or require large amounts of material. A new test apparatus was developed for characterizing the water vapour permeability of fabrics. An aluminium cylinder covered with waterproof and vapour permeable PTFE laminate is used for generating water vapour source on one side of the sample. A dry nitrogen sweep gas stream is used to carry water vapour away. The calculation of the rate of water vapour transmission across the fabric is based on the measurement of the relative humidity of the outgoing nitrogen stream. This new measuring apparatus offers a short test time and calls for a small sample size. The comparison measurements show that the test results correlated well with those obtained from ISO 11092 and ASTM E96. Therefore, this test method provides a new technique to accurately and precisely characterize the water vapour transport properties of fabrics.

  1. Effects of double cropping on summer climate of the North China Plain and neighbouring regions

    NASA Astrophysics Data System (ADS)

    Jeong, S. J.

    2015-12-01

    The North China Plain (NCP) is one of the most important agricultural regions in Asia and produces up to 50% of the cereal consumed in China each year. To meet increasing food demands without expanding croplands, annual agricultural practice in much of the NCP has changed from single to double cropping. The impact of double cropping on the regional climate, through biophysical feedbacks caused by changes in land surface conditions, remains largely unknown. Here we show that observed surface air temperatures during the inter-cropping season (June and July) are 0.40 °C higher over double cropping regions (DCRs) than over single cropping regions (SCRs), with increases in the daily maximum temperature as large as 1.02 °C. Using regional climate modelling, we attribute the higher temperatures in DCRs to reduced evapotranspiration during the inter-cropping period. The higher surface temperatures in June and July affect low-level circulation and, in turn, rainfall associated with the East Asian monsoon over the NCP and neighbouring countries. These findings suggest that double cropping in the NCP can amplify the magnitude of summertime climate changes over East Asia.

  2. On the effect of cloud microstructure on the polarization characteristics of double scattering lidar return

    NASA Astrophysics Data System (ADS)

    Doroshkevich, Anton A.; Bryukhanova, Valentina V.

    2015-11-01

    The work is devoted to remote sensing droplet clouds by coaxial lidar. The results of numerical modeling of the distribution of polarization ellipse parameters of lidar returns in the double-scattering approximation are discussed. It is shown that the polarization state of sounding radiation transforms from a linear (or circular) to the elliptical at the study droplet clouds.

  3. 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

  4. 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.

  5. 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.

  6. 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

    2016-04-01

    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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. Physical properties of vapour grown indium monotelluride platelets

    NASA Astrophysics Data System (ADS)

    Kunjomana, A. G.; Chandrasekharan, K. A.; Teena, M.

    2015-02-01

    Indium monotelluride (InTe) crystals were grown from vapour phase under different temperature gradients by employing physical vapour deposition (PVD) method. The morphology of these crystals such as whiskers, needles, platelets etc., strongly depends on the temperature distribution in the horizontal dual zone furnace. InTe platelets were deposited by setting the temperature of the charge (TC) and growth (TS) zones at 1073 K and 773 K (ΔT=300 K), respectively, for different growth periods (24 h, 48 h, 72 h and 96 h). The surface growth features have been analyzed by scanning electron microscopes, which indicate layer growth mechanism for all the crystals. Various crystals grown under ΔT=200 K and 300 K (retaining TS invariant) were examined by X-ray diffraction and elemental analysis. InTe samples exhibited consistent lattice parameters, density and atomic percentage, establishing stoichiometry and chemical homogeneity. The results obtained for Seebeck coefficient, electrical conductivity, power factor, dislocation density and microhardness are found to be reproducible as well. The vapour deposited InTe platelets are mechanically stable and possess high value of TEP, which ensure their practical application in thermoelectric power generation.

  12. 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

  13. Percutaneous absorption of 2-butoxyethanol vapour in human subjects.

    PubMed Central

    Johanson, G; Boman, A

    1991-01-01

    Four male volunteers were exposed at rest for two periods of two hours, separated by a one hour exposure free interval, to 50 ppm 2-butoxyethanol (BE) vapour generated in an exposure chamber. During the first two hour period the men were exposed by mouth only via a respiratory valve connected by tubes to the exposure chamber. During the second exposure period the men were exposed by skin only while sitting inside the exposure chamber, naked except for shorts, and wearing a respiratory protection mask supplied with compressed air. Capillary blood samples were collected at regular intervals and analysed for BE by a gas chromatographic method. Two experiments separated by at least two weeks were carried out with each volunteer, one at "normal" (23 degrees C, 29% relative humidity) and one at raised (33 degrees C, 71% relative humidity) air temperature and humidity in the chamber. The average concentration in blood and the calculated rate of uptake of BE were about three to four times higher during dermal exposure than during inhalation exposure. These experiments suggest that dermal uptake of BE accounts for about 75% (45-85% in individual experiments) of the total uptake during whole body exposure to BE vapour. Thus it appears that the use of a respiratory protection mask will not protect efficiently against exposure to BE vapours. A tendency towards increased percutaneous absorption rate was seen in the raised temperature and humidity condition. PMID:1954157

  14. Effective Hamiltonian for two interacting double-dot exchange-only qubits and their controlled-NOT operations

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    Double-dot exchange-only qubit represents a promising compromise between high speed and simple fabrication in solid-state implementations. A couple of interacting double-dot exchange-only qubits, each composed by three electrons distributed in a double quantum dot, is exploited to realize controlled-NOT (CNOT) operations. The effective Hamiltonian model of the composite system is expressed by only exchange interactions between pairs of spins. Consequently, the evolution operator has a simple form and represents the starting point for the research of sequences of operations that realize CNOT gates. Two different geometrical configurations of the pair are considered, and a numerical mixed simplex and genetic algorithm is used. We compare the nonphysical case in which all the interactions are controllable from the external and the realistic condition in which intra-dot interactions are fixed by the geometry of the system. In the latter case, we find the CNOT sequences for both the geometrical configurations and we considered a qubit system where electrons are electrostatically confined in two quantum dots in a silicon nanowire. The effects of the geometrical sizes of the nanowire and of the gates on the fundamental parameters controlling the qubit are studied by exploiting a spin-density-functional theory-based simulator. Consequently, CNOT gate performances are evaluated.

  15. Ground-based GPS-derived Precipitable Water Vapour Estimates for Climate Application in Australia

    NASA Astrophysics Data System (ADS)

    Choy, Suelynn; Dawson, John; Jia, Minghai; Kuleshov, Yuriy

    2013-04-01

    Atmospheric water vapour is a critical component of the greenhouse effect and plays a significant role in the global climate system. The knowledge of the long-term spatial and temporal variability of water vapour is vital for understanding climate change. The Global Positioning System (GPS) has long offered the prospect of retrieving column integrated Precipitable Water Vapour (PWV) profiles from the time-varying tropospheric Zenith Path Delay (ZPD), which can be retrieved by stochastic filtering of the GPS measurements. However, observing GPS-PWV for climate studies requires a homogenous and long-term time series of GPS data. We present a regional reanalysis of GPS data focussing on the Australian Regional GPS Network stations from 1997 to 2012 (15 years). These stations are selectively chosen to provide a representative regional distribution of GPS sites on the Australian continent while ensuring conventional meteorological observations (surface-based data) are available for PWV conversion and other PWV sensors (e.g. upper-air data from radiosondes) for validation purposes. The research work is divided into three components: 1) estimation of homogenous long-term tropospheric ZPD from GPS measurements that are accurate, stable and consistent; 2) conversion of tropospheric ZPD to PWV estimates given surface temperature and pressure readings, and 3) intertechnique comparison and validation of the GPS-derived PWV. The derived data will be used to investigate the secular trend and seasonal variation PWV time series and its implications for climate application. This research represents the first attempt to utilise the Australian regional network of GPS stations to study the climate processes and variations from the long-term time series of GPS-PWV.

  16. 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

  17. Disentangling effects of mechanisms that could contribute to the neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Horoi, Mihai; Neacsu, Andrei

    2015-10-01

    Neutrinoless double-beta decay, if observed, would signal physics beyond the Standard Model that could be discovered at energies significantly lower than those at which the relevant degrees of freedom could be excited. Therefore, it could be challenging to further use the neutrinoless double-beta decay observations to distinguish between many beyond Standard Model competing mechanisms to this process. Accurate nuclear structure calculation of the nuclear matrix elements necessary to analyze the decay rates could be helpful to narrow down the list of competing mechanisms, and to better identify the more exotic properties of the neutrinos. We will present information that one can get from the angular and energy distribution of the emitted electron assuming that the right-handed currents exist. Support from U.S. NSF Grant PHY-1404442 and DOE Grant DE-SC0008529 is acknowledged.

  18. Detailed Studies of Projection Effects, Radio Power Selection Effects, and Key Physical Parameters of Classical Double Radio Sources

    NASA Astrophysics Data System (ADS)

    Wan, Lin

    1998-11-01

    A sample of classical double radio sources with redshifts between zero and two was compiled to study the properties of these sources and their gaseous environments. A detailed theoretical investigation of projection effects shows that different derived parameters have different sensitivities to the projection angle /theta, but in general, projection effects are not significant for θsbsp~>60o. Several potential diagnoses of the projection angle are provided by the theoretical studies. Results obtained using one of these methods suggest that the projection angle of Cygnus A is greater than ~40o to 55o, consistent with independent estimates; and the projection angles of other sources in the sample are likely to be greater than 30o to 40o. This is consistent with independent results obtained here by comparing radio galaxies with radio-loud quasars. The data also suggest that low-redshift radio-loud quasars have lower radio surface brightness and non-thermal pressure than radio galaxies, which cannot be explained by pure projection effects. Detailed studies of radio power selection effects suggest that these selection effects are unlikely to be significant for most derived parameters, such as the ambient gas density of the radio source. Results on several key parameters of FRII sources are presented. Studies of the beam power suggest that it remains roughly constant over a source's lifetime. An increase of the beam power with redshift is observed, and it appears that radio power is not an accurate measure of the beam power. Thermal pressures typical of clusters of galaxies are found for the gaseous environments of the FRII sources, which would lead to an appreciable amount of microwave diminution from some of these clusters. The data hint of different pressure gradients at high and low redshift, which may be explained by an increase of cluster core radius with redshift. Preliminary results on the gravitational mass of the surrounding cluster are presented. The redshift

  19. 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

  20. New physics effects on neutrinoless double beta decay from right-handed current

    NASA Astrophysics Data System (ADS)

    Ge, Shao-Feng; Lindner, Manfred; Patra, Sudhanwa

    2015-10-01

    We study the impact of new physics contributions to neutrinoless double beta decay arising from right-handed current in comparison with the standard mechanism. If the light neutrinos obtain their masses from Type-II seesaw within left-right symmetric model, where the Type-I contribution is suppressed to negligible extent, the right-handed PMNS matrix is the same as its left-handed counterpart, making it highly predictable and testable at next-generation experiments. It is very attractive, especially with recent cosmological constraint favoring the normal hierarchy under which the neutrinoless double beta decay is too small to be observed unless new physics appears as indicated by the recent diboson excess observed at ATLAS. The relative contributions from left- and right-handed currents can be reconstructed with the ratio between lifetimes of two different isotopes as well as the ratio of nuclear matrix elements. In this way, the theoretical uncertainties in the calculation of nuclear matrix elements can be essentially avoided. We also discuss the interplay of neutrinoless double beta decay measurements with cosmology, beta decay, and neutrino oscillation.

  1. 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.

  2. Effect of cation ordering on oxygen vacancy diffusion pathways in double perovskites

    DOE PAGESBeta

    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

  3. 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

  4. Large Eddy Simulations of Double-Ruler Electromagnetic Field Effect on Transient Flow During Continuous Casting

    NASA Astrophysics Data System (ADS)

    Singh, Ramnik; Thomas, Brian G.; Vanka, Surya P.

    2014-06-01

    Transient flow during nominally steady conditions is responsible for many intermittent defects during the continuous casting of steel. The double-ruler electromagnetic field configuration, or "FC-Mold EMBr," is popular in commercial slab casting as it provides independent control of the applied static field near the jet and free surface regions of the mold. In the current study, transient flow in a typical commercial caster is simulated in the absence and in the presence of a double-ruler magnetic field, with rulers of equal strengths. Large eddy simulations with the in-house code CU-FLOW resolve the important transient behavior, using grids of over five million cells with a fast parallel solver. In the absence of a magnetic field, a double-roll pattern is observed, with transient unbalanced behavior, high surface velocities (~0.5 m/s), surface vortex formation, and very large surface-level fluctuations (~±12 mm). Applying the magnetic field suppresses the unbalanced behavior, producing a more complex mold flow pattern, but with much lower surface velocities (~0.1 m/s), and a flat surface level with small level fluctuations (<±1 mm). Nail board measurements taken at this commercial caster, in the absence of the field, matched reasonably well with the calculated results, both quantitatively and qualitatively.

  5. 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

  6. 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). PMID:21613038

  7. 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

  8. Double side read-out technique for mitigation of radiation damage effects in PbWO4 crystals

    NASA Astrophysics Data System (ADS)

    Lucchini, M. T.; Auffray, E.; Benaglia, A.; Cavallari, F.; Cockerill, D.; Dolgopolov, A.; Faure, J. L.; Golubev, N.; Hobson, P. R.; Jain, S.; Korjik, M.; Mechinski, V.; Singovski, A.; Tabarelli de Fatis, T.; Tarasov, I.; Zahid, S.

    2016-04-01

    Test beam results of a calorimetric module based on 3×3×22 cm3 PbWO4 crystals, identical to those used in the CMS ECAL Endcaps, read out by a pair of photodetectors coupled to the two opposite sides (front and rear) of each crystal are presented. Nine crystals with different level of induced absorption, from 0 to 20 m‑1, have been tested using electrons in the 50–200 GeV energy range. Photomultiplier tubes have been chosen as photodetectors to allow for a precise measurement of highly damaged crystals. The information provided by this double side read-out configuration allows to correct for event-by-event fluctuations of the longitudinal development of electromagnetic showers. By strongly mitigating the effect of non-uniform light collection efficiency induced by radiation damage, the double side read-out technique significantly improves the energy resolution with respect to a single side read-out configuration. The non-linearity of the response arising in damaged crystals is also corrected by a double side read-out configuration and the response linearity of irradiated crystals is restored. In high radiation environments at future colliders, as it will be the case for detectors operating during the High Luminosity phase of the Large Hadron Collider, defects can be created inside the scintillator volume leading to a non-uniform response of the calorimetric cell. The double side read-out technique presented in this study provides a valuable way to improve the performance of calorimeters based on scintillators whose active volumes are characterized by high aspect ratio cells similar to those used in this study.

  9. Evaluation of the effect of double reporting on test accuracy in screening and diagnostic imaging studies: A review of the evidence.

    PubMed

    Pow, Richard E; Mello-Thoms, Claudia; Brennan, Patrick

    2016-06-01

    Diagnostic error in radiology is not uncommon, with rates of clinically significant error reported to be as high as 20%. Radiological errors are often multifactorial, however, perceptual factors are thought to be mainly responsible. One way of reducing perceptual error is that of double reporting, which refers to the interpretation of radiological investigations by two observers, with strategies of arbitration and consensus available to settle discordant reports. Independent double reporting, where observers have no knowledge of each other's reports, is generally considered to be the most effective form. The impact of double reporting on diagnostic efficacy has been primarily explored in screening mammography, where it has consistently been shown to improve sensitivity, cancer detection rate and depending on local policy, have a positive influence on recall rates. Subsequently, the adoption of double reporting is reported as standard practice in many national and regional breast cancer-screening programmes. To a lesser extent, the impact of double reporting has also been investigated for neuroradiology, thoracic and gastrointestinal imaging, with small-scale studies in these fields showing promising results. With the widespread implementation of digitisation and the ease of access to images, the efficacy and cost-effectiveness of double reporting for other common radiological investigations requires attention. The review will evaluate the evidence regarding the effect of double interpretation of diagnostic imaging studies on test accuracy. PMID:26996634

  10. Effect of spin-flip scattering on the electron transport through double quantum dots

    NASA Astrophysics Data System (ADS)

    Yang, Fu-Bin; Huang, Rui; Cheng, Yan

    2015-05-01

    We systematically investigate the electron transport through double quantum dots (DQD) with particular emphasis on the spin-flip scattering of an electron in the DQD. By means of the slave-boson mean-field approximation, we calculate the linear conductance and the transmission in the Kondo regime at zero temperature. The obtained results show that both the linear conductance and transmission probability are quite sensitive to the spin-flip strength when the DQD structure is changed among the serial, parallel and T-shaped. It is suggested that such a theoretical model can be used to study the physical phenomenon related to the spin manipulation transport.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Effect of the focal shaping generated from different double-mode cylindrical vector beams.

    PubMed

    Cui, Wenjing; Song, Feng; Ju, Dandan; Chen, Gui-Yang; Song, Feifei

    2015-08-01

    We investigate three-dimensional focus shaping generated from double-mode cylindrical vector beams with the Gaussian and Bessel-Gaussian pupil apodization functions by choosing the suitable polarization states of beams. Further, we compare them with that generated from the Laguerre-Gaussian pupil apodization function in the same situation. We find that the focus shaping generated from the Gaussian beam has the smallest zero intensity spot size. However, the situation of the Bessel-Gaussian beam not only possesses stability, which makes it suitable when applied in optical trapping, but also shows the best uniformity, which indicates its excellent performance in super-resolution fluorescence microscopy. PMID:26367303

  16. 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.

  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. 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

  19. 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

  20. 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.

  1. Hoplia coerulea, a porous natural photonic structure as template of optical vapour sensor

    NASA Astrophysics Data System (ADS)

    Mouchet, Sébastien; Su, Bao-Lian; Tabarrant, Tijani; Lucas, Stéphane; Deparis, Olivier

    2013-05-01

    Natural photonic structures found on the cuticle of insects are known to give rise to astonishing structural colours. These ordered porous structures are made of biopolymers, such as chitin, and some of them possess the property to change colour according to the surrounding atmosphere composition. This phenomenon is still not completely understood. We investigated the structure found on the cuticle of the male beetle Hoplia coerulea (Scarabaeidae). The structure, in this case, consists in a 1D periodic porous multilayer inside scales, reflecting incident light in the blue. The colour variations were quantified by reflectance spectral measurements using water, ethanol and acetone vapours. A 1D scattering matrix formalism was used for modelling light reflection on the photonic multilayer. The origin of the reported colour changes has to be tracked in variations of the effective refractive index and of the photonic structure dimensions. This remarkable phenomenon observed for a non-open but still porous multilayer could be very interesting for vapour sensing applications and smart glass windows.

  2. Non-invasive quantification of skin injury resulting from exposure to sulphur mustard and Lewisite vapours.

    PubMed

    Chilcott, R P; Brown, R F; Rice, P

    2000-05-01

    The severity and progression of skin lesions resulting from exposure to the chemical warfare agents Lewisite (L) and sulphur mustard (SM) have been investigated using the non-invasive biophysical methods of evaporimetry and reflectance spectroscopy in large white pigs in vivo. Erythema (redness) expressed immediately after exposure to L or SM vapours appeared to be related to the lesion severity as demonstrated by histopathological analysis. Skin brightness correlated well with scab formation whereas blueness (cyanosis) did not appreciably alter throughout the study. Rates of transepidermal water loss (TEWL) changed both with occlusion (during vapour exposure) and also mirrored the progression of macroscopic skin injury after 12 h. Whilst no single parameter could be used in isolation to ascertain the severity and subsequent progression of the skin lesions, measurement of erythema, skin brightness and TEWL could provide quantitative, non-invasive methods for determining the efficacy of antidotes or therapies to prevent the toxic effects of chemical warfare agents. However, neither colourimetry or TEWL provided a clinical evaluation of such lesions that were comparable with the prognostic capabilities of laser Doppler imaging. PMID:10741590

  3. 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.

  4. 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.

  5. Thin film semiconductor nanomaterials and nanostructures prepared by physical vapour deposition: An atomic force microscopy study

    NASA Astrophysics Data System (ADS)

    Nesheva, D.; Petrova, A.; Stavrev, S.; Levi, Z.; Aneva, Z.

    2007-05-01

    Amorphous/nanocrystalline SiOx/CdSe, GeS2/CdSe, SiOx/ZnSe and Se/CdSe amorphous multilayers (MLs) were grown by consecutive physical vapour deposition of the constituent materials at room substrate temperature. A step-by-step manner of deposition was applied for the preparation of each layer (2 10nm thick) of MLs. Surface morphology has been investigated by atomic force microscopy (AFM) in order to get information about ML interfaces. For a scanned area of 3.4×4μmSiOx/CdSe and GeS2/CdSe MLs showed surface roughness which is around three times greater than the roughness of SiOx/ZnSe MLs. This observation has been connected with effects of both film composition and deposition rate. For a scanned area of 250×250nm the roughness determined in all MLs displayed close values and a similar increase with the ML period. The latter has been related to the flexible structure of amorphous materials. The AFM results, in good agreement with previous X-ray diffraction and high resolution electron microscopy data, indicate that the application of step-by-step physical vapour deposition makes possible fabrication of various amorphous/nanocrystalline MLs with smooth interfaces and good artificial periodicity at low substrate temperatures.

  6. 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. PMID:20934237

  7. Effects of 4-chlorotestosterone acetate on the phagocytic activity of human monocytes: results of double-blind trial

    PubMed Central

    Magliulo, E.; Giraldi, M.; Cattaneo, E.; Marchioni, E.

    1972-01-01

    A comparative trial on 4-chlorotestosterone acetate and placebo was conducted in humans by the double-blind technique. The effects of the drug were tested by measuring the phagocytic activity of blood monocytes in vitro for colloidal carbon. Monocytes from patients treated with 4-chlorotestosterone acetate displayed a phagocytic power significantly higher than that of monocytes from patients treated with the placebo. Such an increased phagocytic activity is discussed in relation to cell mechanisms and their role in anti-infective defence. ImagesFig. 1 PMID:4556011

  8. 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.

  9. Ketoprofen vs etofenamate in a controlled double-blind study: evidence of topical effectiveness in soft tissue rheumatic pain.

    PubMed

    Matucci-Cerinic, M; Casini, A

    1988-01-01

    The efficacy and safety of topical application of ketoprofen gel and etofenamate gel were studied in a controlled double-blind clinical trial. Thirty-six patients affected by inflammation of tendons, sheaths and bursae entered the study, and were treated for seven days. The parameters studied were: pain scale, Ritchie index, stiffness, pain on active and passive movement and functional capacity. The results showed that ketoprofen gel and etofenamate gel were able to induce remission of the inflammatory symptoms in soft tissue rheumatic pain. No side-effects were detected in either group. PMID:3042643

  10. 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.

  11. 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.

  12. 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.

  13. 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. PMID:8976600

  14. 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

  15. 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

  16. The Development Of Gold And Copper Vapour Lasers For Medical Applications In Australia

    NASA Astrophysics Data System (ADS)

    Stanco, Alex

    1987-04-01

    The first fully automated mobile copper and gold vapour lasers for medical applications were developed in Australia. The history of this development program is presented in this paper. These lasers have been tested in several clinical programs and success with the gold vapour laser in cancer phototherapy using HpD has been achieved in various types of tumours. Trials have commenced on the use of the 578 nm yellow line of the copper vapour laser for dermatology and plastic surgery.

  17. 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)

  18. Phase correction of VLBI with water vapour radiometry

    NASA Astrophysics Data System (ADS)

    Roy, Alan; Rottmann, H.; Teuber, U.; Keller, R.

    We demonstrate phase correction of 3-mm VLBI observations using the scanning 18-GHz to 26GHz water vapour radiometer (WVR) at Effelsberg and we demonstrate an absolute accuracy of 15-mm in zenith path delay by comparing with GPS and radiosondes. This accuracy should provide significant improvement in astrometric phase-referencing observations. It is not good enough for geodetic VLBI to replace the tropospheric delay estimation but could be used to remove short-term path-length fluctuations and so improve the geodetic observables. We discuss lessons learned and opportunities for further improvement.

  19. Microscopic characterisation of suspended graphene grown by chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Bignardi, Luca; van Dorp, Willem F.; Gottardi, Stefano; Ivashenko, Oleksii; Dudin, Pavel; Barinov, Alexei; de Hosson, Jeff Th. M.; Stöhr, Meike; Rudolf, Petra

    2013-09-01

    We present a multi-technique characterisation of graphene grown by chemical vapour deposition (CVD) and thereafter transferred to and suspended on a grid for transmission electron microscopy (TEM). The properties of the electronic band structure are investigated by angle-resolved photoelectron spectromicroscopy, while the structural and crystalline properties are studied by TEM and Raman spectroscopy. We demonstrate that the suspended graphene membrane locally shows electronic properties comparable with those of samples prepared by micromechanical cleaving of graphite. Measurements show that the area of high quality suspended graphene is limited by the folding of the graphene during the transfer.

  20. Microscopic characterisation of suspended graphene grown by chemical vapour deposition.

    PubMed

    Bignardi, Luca; van Dorp, Willem F; Gottardi, Stefano; Ivashenko, Oleksii; Dudin, Pavel; Barinov, Alexei; De Hosson, Jeff Th M; Stöhr, Meike; Rudolf, Petra

    2013-10-01

    We present a multi-technique characterisation of graphene grown by chemical vapour deposition (CVD) and thereafter transferred to and suspended on a grid for transmission electron microscopy (TEM). The properties of the electronic band structure are investigated by angle-resolved photoelectron spectromicroscopy, while the structural and crystalline properties are studied by TEM and Raman spectroscopy. We demonstrate that the suspended graphene membrane locally shows electronic properties comparable with those of samples prepared by micromechanical cleaving of graphite. Measurements show that the area of high quality suspended graphene is limited by the folding of the graphene during the transfer. PMID:23945527

  1. 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.

  2. Optimal repetition rates of excitation pulses in a Tm-vapour laser

    NASA Astrophysics Data System (ADS)

    Gerasimov, V. A.; Gerasimov, V. V.; Pavlinskii, A. V.

    2011-01-01

    The optimal excitation pulse repetition rates (PRRs) for a gas-discharge Tm-vapour laser with indirect population of upper laser levels are determined. It is shown that, under the same excitation conditions, the optimal PRRs increase with a decrease in the energy defect between the upper laser acceptor level and the nearest resonant donor level. The reasons for the limitation of the optimal PRRs in Tm-vapour laser are discussed. It is shown that the maximum average power of Tm-vapour laser radiation may exceed several times the Cu-vapour laser power under the same excitation conditions and in identical gas-discharge tubes.

  3. Split-sample comparison of directional and liquid nitrogen vapour freezing method on post-thaw semen quality in white rhinoceroses (Ceratotherium simum simum and Ceratotherium simum cottoni).

    PubMed

    Reid, C E; Hermes, R; Blottner, S; Goeritz, F; Wibbelt, G; Walzer, C; Bryant, B R; Portas, T J; Streich, W J; Hildebrandt, T B

    2009-01-15

    To increase the quality of cryopreserved sperm in white rhinoceros, the liquid nitrogen vapour (LN vapour) freezing and the multi-thermal gradient directional freezing methods were compared. Sixteen white rhinoceros (Ceratotherium simum sp.) were electro-ejaculated. Semen samples were diluted with cryoextender (Tris, lactose, egg-yolk, DMSO) and aliquoted into straws for LN vapour freezing, and glass hollow tubes for directional freezing. The sperm quality was evaluated before and after freezing by assessing the following parameters: motility, morphologic state, acrosomal integrity and plasma membrane function and integrity (i.e. sperm viability) as defined by the hypo-osmotic swelling. Directional freezing improved the sperm viability by 5.6% (p<0.005), progressive motility score by 34.7% and sperm motility index (SMI) by 8.1% (p<0.005) versus LN vapour freezing. When data was categorized into groups of low (<19%), moderate (20-39%) and high (>40%) percentages of morphologically normal, directional freezing (DF) resulted in 31.4% less abnormal acrosomes for the low quality group as well as 18.7% increase in intact acrosomes and 10.9% increase in motility for the high quality group compared to LN vapour freezing (LN) (p<0.01, p<0.03, p<0.01, respectively). LN showed a significant reduction in sperm head volume (5.7%, p<0.05) compared to the prefreeze; whereas, no significant reduction in head volume was demonstrated after DF. Several additives (xanthenuric acid, cytochalasin D, potassium, EDTA) to the basic cryoextender provided no significant improvement in spermatozoal survival after directional freezing. In conclusion, directional freezing proved to facilitate higher gamete survival compared to LN vapour freezing. This is especially effective in ejaculates of low sperm quality and is important in endangered species where high quality semen donors are often not accessible. These results suggest that directional freezing could be valuable particularly for species

  4. Double-fiber electric current measurements applying thermal-lens-coupled magneto-optical effect in ferrofluid

    NASA Astrophysics Data System (ADS)

    Li, Hongjie; Chen, Xiaowei; Yuan, Suihua

    1998-08-01

    The optical current transformer (OCT) reported in the past decades is mainly based on the traditional principle of Faraday rotation effect. Presented is a new type of OCT based on a new physical effect, the thermal lens coupled magneto-optical effect in ferrofluid. The use of optical array in the measuring system made the instrument complicated and expensive. This paper proposes applying double fibers to detect the current-corresponding variation of light intensity of the diffraction rings to simplify the instrumental structure. The fluctuations of the laser beam were eliminated by differential optical paths. Results obtained showed a DC measurement accuracy of 1 percent with a dynamic range of 0-500 angstrom, extendible to 2000 angstrom. All experiments were computerized. The set-up can also be applied to measure AC currents with similar qualities to the DC case.

  5. Effect of composite collector design on the breakdown behavior of InGaP/GaAs double heterojunction bipolar transistor

    NASA Astrophysics Data System (ADS)

    Lew, K. L.; Yoon, S. F.

    2003-01-01

    A series of experiments and calculations has been carried out to study the effect of different composite collector designs on InGaP/GaAs/InGaP double heterojunction bipolar transistor breakdown characteristics. A comparison between uncorrected and dead-space corrected models was carried out, and it was found that the dead-space effect is dominant for collector thickness below 300 nm. However, this effect can be neglected for collector thickness larger than 500 nm. The role of lightly doped GaAs (n--GaAs) and heavily doped InGaP (N+-InGaP) spacer layers is discussed systematically to establish a criterion for designing the composite collector structure. The experimental and theoretical results show that it is necessary to keep the sum of n--GaAs and N+-InGaP spacer layer thickness below 50 nm to avoid significant degradation of the device breakdown characteristics.

  6. Double-blind comparison of the respiratory and sedative effects of codeine phosphate and (+/-)-glaucine phosphate in human volunteers.

    PubMed Central

    Redpath, J B; Pleuvry, B J

    1982-01-01

    1 Two antitussive agents (+/-)-glaucine phosphate and codeine phosphate have been compared with placebo with respect to ventilation, ventilatory response to carbon dioxide, pulse, blood pressure, digit symbol substitution, sedation score and the Zahlen-Verbindung test performance in ten healthy volunteers (22-36 years). The study was double-blind and the two doses of each antitussive agent and the placebo were administered as a syrup. 2 Both codeine phosphate and (+/-)-glaucine phosphate displaced the ventilatory response to carbon dioxide to the right. 3 The effect of codeine phosphate on the ventilatory response to carbon dioxide was not dose dependent: 30 mg produced greater effects than the 60 mg dose. 4 Only the highest dose of (+/-)-glaucine phosphate (60 mg) caused respiratory depression and this was associated with sedation and decreased performance in the digit symbol substitution test. 5 Neither antitussive agent had significant effects upon pulse or blood pressure and codeine phosphate had no detectable sedative activity. PMID:6814470

  7. 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.

  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. Two-mode effective interaction in a double-well condensate

    NASA Astrophysics Data System (ADS)

    Jezek, D. M.; Capuzzi, P.; Cataldo, H. M.

    2013-05-01

    We investigate the origin of a disagreement between the two-mode model and the exact Gross-Pitaevskii dynamics applied to double-well systems. In general this model, even in its improved version, predicts a faster dynamics and underestimates the critical population imbalance separating Josephson and self-trapping regimes. We show that the source of this mismatch in the dynamics lies in the value of the on-site interaction energy parameter. Using simplified Thomas-Fermi densities, we find that the on-site energy parameter exhibits a linear dependence on the population imbalance, which is also confirmed by Gross-Pitaevskii simulations. When introducing this dependence in the two-mode equations of motion, we obtain a reduced interaction energy parameter which depends on the dimensionality of the system. The use of this parameter significantly heals the disagreement in the dynamics and also produces better estimates of the critical imbalance.

  10. The effect of the superhelicity on the double helix twist angle in DNA.

    PubMed Central

    Belintsev, B N; Gagua, A V; Nedospasov, S A

    1979-01-01

    An attempt to estimate the relative contributions of twisting and bending to the free energy of superhelix formation from the relaxed DNA is undertaken. The extent of teritiary ordering (number of DNA axis turns tau) and that of secondary ordering (duplex twist angle beta) have been taken as thermodynamical parameters, which characterize the state of the supercoild DNA at the fixed linking number (Lk) value. Such a thermodynamical approach implies the phenomenological parameters of rigidities of twisting and supercoiling (Gbeta, Gtau). Gtau/Gbeta ratio is estimated from the presented experimental data on the winding of the double helix upon increasing the ionic strength when twist alterations are followed by circular dichroism method. The adequacy of such interpretation of CD spectra changes are discussed. The values of Gtau and Gbeta are estimated to be of the same order of magnitude. PMID:220593

  11. 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.

  12. 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.

  13. Effect of interdots electronic repulsion in the Majorana signature for a double dot interferometer

    NASA Astrophysics Data System (ADS)

    Ricco, L. S.; Marques, Y.; Dessotti, F. A.; de Souza, M.; Seridonio, A. C.

    2016-04-01

    We investigate theoretically the features of the Majorana hallmark in the presence of Coulomb repulsion between two quantum dots describing a spinless double dot interferometer, where one of the dots is strongly coupled to a Kitaev wire within the topological phase. Such a system has been originally proposed without Coulomb interaction in Dessotti et al. (2014 [16]) . Our findings reveal that for dots in resonance, the ratio between the strength of Coulomb repulsion and the dot-wire coupling changes the width of the Majorana zero-bias peak for both Fano regimes studied, indicating thus that the electronic interdots correlation influences the Majorana state lifetime in the dot hybridized with the wire. Moreover, for the off-resonance case, the swap between the energy levels of the dots also modifies the width of the Majorana peak, which does not happen for the noninteracting case. The results obtained here can guide experimentalists that pursuit a way of revealing Majorana signatures.

  14. 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.

  15. 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.

    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.

  16. 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.

    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.

  17. 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.

  18. 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

  19. Investigation of proton irradiation effects on InP/InGaAs double heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Liu, Min; Zhang, Yuming; Lu, Hongliang; Zhang, Yimen; Zhang, Jincan; Ren, Xiaotang

    2015-07-01

    In this article, 3 MeV proton irradiation-induced degradation in InP/InGaAs double heterojunction bipolar transistors (DHBTs) is studied, the fluence up to 5 × 1012 protons/cm2, meanwhile 10 MeV proton irradiation is investigated in order to compare the differences induced by different proton energy irradiation. The devices exhibit good tolerance up to 5 × 1011 protons/cm2. The concentration of vacancies at different proton fluences can be calculated from SRIM. Being donor-like defects, the In and Ga vacancies act as compensation center while As vacancy acts as an acceptor-like defect. Adding the vacancies model into Sentaurus device simulator, simulation results match well with the trends of measured data.

  20. 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.

  1. Double-blind maintenance safety and effectiveness findings from the Treatment of Early-Onset Schizophrenia Spectrum Study (TEOSS)

    PubMed Central

    Findling, Robert L; Johnson, Jacqueline L; McClellan, Jon; Frazier, Jean A; Vitiello, Benedetto; Hamer, Robert M; Lieberman, Jeffrey A; Ritz, Louise; McNamara, Nora K; Lingler, Jacqui; Hlastala, Stefanie; Pierson, Leslie; Puglia, Madeline; Maloney, Ann E; Kaufman, Emily Michael; Noyes, Nancy; Sikich, Linmarie

    2010-01-01

    OBJECTIVE To examine the long-term safety and efficacy of three antipsychotics in early-onset schizophrenia spectrum disorders (EOSS). METHOD Patients (age 8–19 years) who had improved during an 8-week, randomized double-blind acute trial of olanzapine, risperidone, or molindone (plus benztropine) were eligible to continue on the same medication for up to 44 additional weeks under double-blind conditions. Adjunctive medications were allowed following defined algorithms. Standardized symptom, safety, and functional assessments were conducted every 4 weeks. RESULTS Of the 116 youth randomized in the acute trial, 54 entered maintenance treatment (molindone, N=20; olanzapine, N=13; risperidone, N=21). Fourteen (26%) completed 44 weeks of treatment. Adverse effects (N=15), inadequate efficacy (N=14), or study non-adherence (N=8) were the most common reasons for discontinuation. The three treatment arms did not significantly differ in symptom reduction or time to discontinuation. Akathisia was more common with molindone and elevated prolactin concentrations more common with risperidone. Although weight gain and metabolic adverse events had occurred more often with olanzapine and risperidone during the acute trial, no significant between-drug differences emerged in most of these parameters during maintenance treatment. CONCLUSIONS Only 12 % of youth with EOSS continued on their originally randomized treatment at 52 weeks. No agent demonstrated superior efficacy, and all were associated with side effects, including weight gain. Improved treatments are needed for EOSS. PMID:20494268

  2. Is ginger effective for the treatment of Irritable Bowel Syndrome? A double blind randomized controlled pilot trial

    PubMed Central

    VAN TILBURG, Miranda A.L.; PALSSON, Olafur S.; RINGEL, Yehuda; WHITEHEAD, William E

    2014-01-01

    Objectives Ginger is one of the most commonly used herbal medicine for Irritable Bowel Syndrome (IBS) but no data exists about its effectiveness. Design Double blind randomized controlled trial Setting University of North Carolina, Chapel Hill North Carolina, USA Intervention Forty-five IBS patients were randomly assigned to three groups: placebo, one gram of ginger, and two grams of ginger daily for 28 days. Main outcome measures The IBS severity scale (IBS-SS) was administered, as well as adequate relief of symptoms scale. A responder was defined as having at least 25% reduction in IBS-SS post-treatment. Results There were 57.1% responders to placebo, 46.7% to one gram and 33.3% to two grams of ginger. Adequate relief was reported by 53.3% on placebo and 53.3% in both ginger groups combined. Side effects were mild and reported by 35.7% in the placebo and 16.7% in the ginger groups. Conclusions This double blind randomized controlled pilot study suggests ginger is well tolerated but did not perform better than placebo. Larger trials are needed before any definitive conclusions can be drawn. PMID:24559811

  3. 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.

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

    PubMed

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

    2010-03-01

    A continuous record of atmospheric vapour isotopic composition (delta(A)) can be derived from the isotope mass balance of a water body submitted to natural evaporation. In this paper, we present preliminary results of the application of this method to a drying evaporation pan, located in a Mediterranean wetland, during a two-month summer period. Results seem consistent with few atmospheric vapour data based on the assumption of isotopic equilibrium with precipitation, but we observed a shift between pan-derived delta(A) and the composition of vapour samples collected by cold trapping. These results suggest that further investigations are necessary to evaluate the effect of diurnal variations of atmospheric conditions on the applicability of the pan-evaporation method, and on the representative of grab atmospheric samples. We also propose a sensitivity analysis for evaluating the impact of the different measured components on delta(A) calculation, and show an improvement in the method efficiency as the pan is drying. PMID:20099185

  5. Water vapour jets inside the plume of gas leaving Enceladus.

    PubMed

    Hansen, C J; Esposito, L W; Stewart, A I F; Meinke, B; Wallis, B; Colwell, J E; Hendrix, A R; Larsen, K; Pryor, W; Tian, F

    2008-11-27

    A plume of water vapour escapes from fissures crossing the south polar region of the Saturnian moon Enceladus. Tidal deformation of a thin surface crust above an internal ocean could result in tensile and compressive stresses that would affect the width of the fissures; therefore, the quantity of water vapour released at different locations in Enceladus' eccentric orbit is a crucial measurement of tidal control of venting. Here we report observations of an occultation of a star by the plume on 24 October 2007 that revealed four high-density gas jets superimposed on the background plume. The gas jet positions coincide with those of dust jets reported elsewhere inside the plume. The maximum water column density in the plume is about twice the density reported earlier. The density ratio does not agree with predictions-we should have seen less water than was observed in 2005. The ratio of the jets' bulk vertical velocities to their thermal velocities is 1.5 +/- 0.2, which supports the hypothesis that the source of the plume is liquid water, with gas accelerated to supersonic velocity in nozzle-like channels. PMID:19037310

  6. A review of water recovery by vapour permeation through membranes.

    PubMed

    Bolto, Brian; Hoang, Manh; Xie, Zongli

    2012-02-01

    In vapour permeation the feed is a vapour, not a liquid as in pervaporation. The process employs a polymeric membrane as a semi-permeable barrier between the feed side under high pressure and the permeate side under low pressure. Separation is achieved by the different degrees to which components are dissolved in and diffuse through the membrane, the system working according to a solution-diffusion mechanism. The materials used in the membrane depend upon the types of compounds being separated, so water transport is favoured by hydrophilic material, whether organic or inorganic. The process is used for the dehydration of natural gas and various organic solvents, notably alcohol as biofuel, as well as the removal of water from air and its recovery from waste steam. Waste steam can be found in almost every plant/factory where steam is used. It is frequently contaminated and cannot be reused. Discharging the spent steam to the atmosphere is a serious energy loss and environmental issue. Recycling the steam can significantly improve the overall energy efficiency of an industry, which is responsible for massive CO(2) emissions. Steam separation at high fluxes and temperatures has been accomplished with a composite poly(vinyl alcohol) membrane containing silica nanoparticles, and also, less efficiently, with an inorganic zeolite membrane. PMID:22100055

  7. 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.

  8. 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.

  9. Improved grand canonical sampling of vapour-liquid transitions.

    PubMed

    Wilding, Nigel B

    2016-10-19

    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. PMID:27546280

  10. 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

  11. 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. PMID:26442146

  12. 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

  13. Ferromagnetic resonance of patterned chromium dioxide thin films grown by selective area chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Durrant, C. J.; Jokubaitis, M.; Yu, W.; Mohamad, H.; Shelford, L. R.; Keatley, P. S.; Xiao, Gang; Hicken, R. J.

    2015-05-01

    A selective area chemical vapour deposition technique has been used to fabricate continuous and patterned epitaxial CrO2 thin films on (100)-oriented TiO2 substrates. Precessional magnetization dynamics were stimulated both electrically and optically, and probed by means of time-resolved Kerr microscopy and vector network analyser ferromagnetic resonance techniques. The dependence of the precession frequency and the effective damping parameter upon the static applied magnetic field were investigated. All films exhibited a large in-plane uniaxial anisotropy. The effective damping parameter was found to exhibit strong field dependence in the vicinity of the hard axis saturation field. However, continuous and patterned films were found to possess generally similar dynamic properties, confirming the suitability of the deposition technique for fabrication of future spintronic devices.

  14. 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

  15. 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.

  16. 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

  17. The effect of an electrical double layer on the voltammetric performance of nanoscale interdigitated electrodes: a simulation study

    NASA Astrophysics Data System (ADS)

    Yang, Xiaoling; Zhang, Guigen

    2008-11-01

    Finite-element based computational simulation is performed to investigate the effect of an electrical double layer (EDL) on the electrochemical processes of nanometer-scale interdigitated electrodes (nano-IDEs). Results show that the EDL structure will alter the voltammetric current response of nano-IDEs due to the expansion of the diffuse layer into the diffusion layer at the electrode surfaces and the overlap of the electrical fields of the neighboring electrodes. The EDL induced change in the voltammetric current response is more severe for nano-IDEs with a smaller electrode size and gap spacing, and the EDL effect is influenced by the compact layer thickness, the charge valence of the redox species, the electron transfer rate, and the absence of the supporting electrolyte.

  18. 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.

  19. The effect of oral nitroglycerin on portal blood velocity as measured by ultrasonic Doppler. A double blind, placebo controlled study.

    PubMed

    Yang, S S; Ralls, P W; Korula, J

    1991-04-01

    We studied the effect of oral nitroglycerin on portal blood velocity (PBV) in 20 cirrhotic patients by a double blind, placebo controlled method using noninvasive Doppler sonography. After we obtained baseline Doppler in the fasting state, 0.6 mg nitroglycerin or placebo was given orally and the mean of 3 s averaged mean PBVs was repeated at 5 min intervals for 60 min. Ten patients each received nitroglycerin or placebo. Portal vein flows were antegrade in all. Of the 10 patients receiving nitroglycerin, seven (P = 0.002) showed a greater than 10% fall in the mean PBVs for at least 15 min. Of these seven "responders," five patients had a 10% decrease in mean systemic blood pressure for at least 15 min. None of the "nonresponders" had systemic hypotension. Our study suggests that the PBV-reducing effect of nitroglycerin in cirrhotics may be explained in part by systemic hypotension. PMID:1903409

  20. Biochemical effects of low level exposure to soman vapour.

    PubMed

    Bajgar, J; Sevelová, L; Krejcová, G; Fusek, J; Vachek, J; Kassa, J; Herink, J; de Jong, L P A; Benschop, H

    2004-03-01

    The aim of this study was to demonstrate changes in acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities, tyrosine aminotransferase activity (TAT) and plasma corticosterone level, neuroexcitability and behavior following 24 hours and 4 weeks of soman sublethal inhalation exposure at low level. AChE activity in erythrocytes and BuChE activity in plasma was decreased (dependent on the concentration of soman) 24 h and 4 weeks after the exposure. Similar decrease in AChE activity in different brain parts was observed. One of stressogenic parameters (TAT) was changed after 24 h exposure only. 4 weeks after the exposure, these parameters (corticosterone and TAT) were in the range of normal values. Behaviour of experimental animals was changed 24 h after the exposure persisting 4 weeks after the exposure as well as neuroexcitability. PMID:15141961

  1. 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.

  2. 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.

  3. 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.

  4. 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. PMID:26839606

  5. 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

  6. Emerging double helical nanostructures

    NASA Astrophysics Data System (ADS)

    Zhao, Meng-Qiang; Zhang, Qiang; Tian, Gui-Li; Wei, Fei

    2014-07-01

    As one of the most important and land-mark structures found in nature, a double helix consists of two congruent single helices with the same axis or a translation along the axis. This double helical structure renders the deoxyribonucleic acid (DNA) the crucial biomolecule in evolution and metabolism. DNA-like double helical nanostructures are probably the most fantastic yet ubiquitous geometry at the nanoscale level, which are expected to exhibit exceptional and even rather different properties due to the unique organization of the two single helices and their synergistic effect. The organization of nanomaterials into double helical structures is an emerging hot topic for nanomaterials science due to their promising exceptional unique properties and applications. This review focuses on the state-of-the-art research progress for the fabrication of double-helical nanostructures based on `bottom-up' and `top-down' strategies. The relevant nanoscale, mesoscale, and macroscopic scale fabrication methods, as well as the properties of the double helical nanostructures are included. Critical perspectives are devoted to the synthesis principles and potential applications in this emerging research area. A multidisciplinary approach from the scope of nanoscience, physics, chemistry, materials, engineering, and other application areas is still required to the well-controlled and large-scale synthesis, mechanism, property, and application exploration of double helical nanostructures.

  7. Hydroxy double salt anion exchange kinetics: effects of precursor structure and anion size.

    PubMed

    Kandare, Everson; Hossenlopp, Jeanne M

    2005-05-01

    (1)H NMR spectroscopy and powder X-ray diffraction have been used to explore the details of anion exchange reactions of two layered hydroxy double salts (HDSs), zinc copper hydroxy acetate (ZCA), nickel zinc hydroxy acetate (NZA), and a related layered material, zinc hydroxy acetate (ZHA), at room temperature (21-22 degrees C). Reactions that followed Avrami-Erofe'ev kinetics with respect to temporal profiles for acetate release, ZCA with butyrate (k = 1.7 x 10(-3) s(-1)), and octanoate (k = 0.79 x 10(-3) s(-1)) anions, as well as ZHA with octanoate (k = 2.6 x 10(-3) s(-1)), demonstrate that rate constants for acetate release are influenced by the exchange anion relative size as well as by the solid precursor structure/composition. The reaction of NZA with octanoate deviated from expected Avrami-Erofe'ev behavior, with evidence for an intermediate species in the solid phase that may influence the rate of acetate release into solution. The reaction of ZCA with formate anions exhibited a unique zeroth-order kinetics release of acetate, providing the possibility of developing tunable nanostructured anion release sources by use of variations in the size of the exchange species. PMID:16851994

  8. The effect of Neuragen PN® on Neuropathic pain: A randomized, double blind, placebo controlled clinical trial

    PubMed Central

    2010-01-01

    Background A double blind, randomized, placebo controlled study to evaluate the safety and efficacy of the naturally derived topical oil, "Neuragen PN®" for the treatment of neuropathic pain. Methods Sixty participants with plantar cutaneous (foot sole) pain due to all cause peripheral neuropathy were recruited from the community. Each subject was randomly assigned to receive one of two treatments (Neuragen PN® or placebo) per week in a crossover design. The primary outcome measure was acute spontaneous pain level as reported on a visual analog scale. Results There was an overall pain reduction for both treatments from pre to post application. As compared to the placebo, Neuragen PN® led to significantly (p < .05) greater pain reduction. Fifty six of sixty subjects (93.3%) receiving Neuragen PN® reported pain reduction within 30 minutes. This reduction within 30 minutes occurred in only twenty one of sixty (35.0%) subjects receiving the placebo. In a break out analysis of the diabetic only subgroup, 94% of subjects in the Neuragen PN® group achieved pain reduction within 30 minutes vs 11.0% of the placebo group. No adverse events were observed. Conclusions This randomized, placebo controlled, clinical trial with crossover design revealed that the naturally derived oil, Neuragen PN®, provided significant relief from neuropathic pain in an all cause neuropathy group. Participants with diabetes within this group experienced similar pain relief. Trial registration ISRCTN registered: ISRCTN13226601 PMID:20487567

  9. 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.

  10. 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

  11. Reynolds number effects on the vortical-flow structure generated by a double-delta wing

    NASA Astrophysics Data System (ADS)

    Hebbar, S. K.; Platzer, M. F.; Fritzelas, A. E.

    An experimental investigation of the high-incidence vortical flowfield over a 76/40° double-delta wing model with sharp leading edges was conducted in the Naval Postgraduate School water tunnel facility at three nominal flow Reynolds numbers of 15000, 45000, and 75000 (based on centerline chord). Extensive flow visualization studies were performed with the dye-injection technique, followed by laser Doppler velocity measurements. The primary objective of this investigation was the determination of the influence of Reynolds number on vortex interactions/trajectories, and breakdown. It was found that there is a significant influence of Reynolds number. Specifically, with the increase of flow Reynolds number the strake and wing vortex trajectories tend to move outboards and closer to the model surface, and the vortex breakdown location moves forwards toward the apex of the model. The intertwining or coiling-up feature of the vortex interaction phenomenon becomes less dominant and disappears altogether at high Reynolds numbers. These trends in the vortex interaction and bursting data are found to be in good agreement with previous wind tunnel data.

  12. 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

  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. 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

    2016-01-01

    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(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. PMID:27255577

  15. Pulse-duration effect in nonsequential double ionization of Ar atoms

    NASA Astrophysics Data System (ADS)

    Dong, Shansi; Chen, Xiang; Zhang, Jingtao; Ren, Xianghe

    2016-05-01

    Nonsequential double ionization of Ar atoms in intense few-cycle laser pulses is studied by a classical ensemble method. The laser pulses are of trapezoidal shape with one cycle in both ramp on and ramp off. We obtain the cycle-resolved electron dynamics by increasing the optical cycles in the laser pulse one by one. We find that, at the higher laser intensity, the correlated-electron momentum distribution (CMD) in the three-cycle laser pulse exhibits two predominate structures in the first and third quadrants. They are formed by the electron pairs in which the second electron is knocked out by the returning electron in the second cycle. As the pulse duration increases, more electron pairs accumulate in the second and fourth quadrants of the CMDs. In these electron pairs, the second electron is first excited owing to collision with the returning electron and then is ionized by the laser field. By varying the peak intensity, we show the transition of the CMDs from anticorrelation to correlation in three-cycle laser pulses, which disproves that multiple collisions cause the transition.

  16. The recovery of VOC from vapours and condensates by membrane processes

    SciTech Connect

    Chmiel, H.; Mavrov, V.; Faehnrich, A.

    1995-12-31

    Membrane separation processes, applied individually or combined with other separation processes, have proven to be particularly suitable for integration into production processes. This paper provides examples which focus on the recovery of volatile organic components from exhaust air, vapours and condensates by membrane processes. The processes described are vapour permeation combined with adsorption, nanofiltration, and reverse osmosis.

  17. The millennium water vapour drop in the stratosphere in chemistry-climate model simulations

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    This study investigates the millennium water vapour drop, the abrupt and severe water vapour decline in the stratosphere beginning in year 2000, by means of various simulations using the Chemistry-Climate Model (CCM) EMAC. Since the beginning 1980s, balloon borne stratospheric water vapour measurements and corresponding satellite measurements starting in the early 1990s indicated a long-term steady increase of water vapour concentrations. However, the multi-year data sets also show significant fluctuations on different time scales. In the year 2000, an extraordinary sudden drop of stratospheric water vapour concentration has been observed followed by persistent low values for several years. Solomon et al. (2010) showed that this drop slowed down the rate of increase in global surface temperature over the following decade by about 25%. So far, the stratospheric water vapour variations observed by satellite from 1992 to 2012 are not reproduced by CCM simulations forced by observed changes in sea surface temperatures, greenhouse gases and ozone-depleting substances (Gettelman et al., 2010, Randel and Jensen, 2013). However, the CCM EMAC is able to reproduce the signature and pattern of the water vapour disturbances in agreement with those derived from observations. In this paper we present results of a hierarchy of simulations with the CCM EMAC, demonstrating that it is possible to retrace the observed water vapour fluctuations in the stratosphere (incl. the millennium drop), if suitable inner and outer boundary conditions are applied.

  18. Effects of PEMF on patients with osteoarthritis: Results of a prospective, placebo-controlled, double-blind study.

    PubMed

    Wuschech, Heinz; von Hehn, Ulrike; Mikus, Eberhard; Funk, Richard H

    2015-12-01

    This study aimed to evaluate effects of pulsed electromagnetic fields (PEMF) in a double blind study on patients with knee joint osteoarthritis. The MAGCELL ARTHRO electrode-less therapy delivered a sinusoidal magnetic field, varying in frequency between 4 and 12 Hz. In 1 cm tissue depth, magnetic flux density was 105 mT. A total of n = 57 patients were randomly assigned to the verum, PEMF or placebo group (placebo device). Their average age was 61.6 ± 12.0 years. According to American College of Rheumatology criteria the osteoarthritis level was 2.8 ± 0.8. Treatment was performed twice a day for 5 min over a period of 18 days. Treatment with the MAGCELL device versus control (sham exposed) showed a highly significant reduction in pain (P < 0.001), a significant reduction in stiffness (P = 0.032) and a significant reduction in disability in daily activities (P = 0.005) according to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scales-with a good overall treatment tolerance. In the placebo group there was no evidence of a significant change between the initial and final examination in any of the three above-mentioned WOMAC scales. Results of this partly randomized placebo-controlled double-blind study show clinically at any rate, that use of PEMF lead to highly significant better results in the treatment group compared to the placebo group with regard to the total WOMAC global score and especially for visual analogue scale. Patient assessment of the "effectiveness" was rated in 29.5% as very good and good in 27.3% compared to 0.0% and 15.4% in controls. This therapy is thus a useful complementary treatment option with no side effects. PMID:26562074

  19. 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

  20. Double umbilical cord blood transplant is effective therapy for relapsed or refractory Hodgkin lymphoma.

    PubMed

    Thompson, Philip A; Perera, Travis; Marin, David; Oran, Betul; Popat, Uday; Qazilbash, Muzaffar; Shah, Nina; Parmar, Simrit; Rezvani, Katayoun; Olson, Amanda; Kebriaei, Partow; Anderlini, Paolo; Rondon, Gabriela; Alousi, Amin; Ciurea, Stefan; Champlin, Richard E; Bajel, Ashish; Szer, Jeffrey; Shpall, Elizabeth J; Ritchie, David; Hosing, Chitra M

    2016-07-01

    A sub-group of patients with Hodgkin Lymphoma (HL) who relapse after autologous stem cell transplant can achieve long-term disease-free-survival after allogeneic stem cell transplant (alloSCT). There is limited information regarding the tolerability and efficacy of double umbilical cord blood transplant (dUCBT) for relapsed/refractory HL. We analyzed 27 consecutive, heavily pre-treated patients receiving dUCBT for relapsed/refractory HL at two centers from 2003-2014. The majority of patients relapsed <6 months after autologous stem cell transplant. A total of 15 patients received myeloablative (most commonly melphalan, fludarabine, thiotepa and anti-thymocyte globulin [ATG]) and 12 non-myeloablative conditioning regimens (fludarabine, cyclophosphamide, 200cGy total body irradiation +/- ATG). All patients engrafted; median time to neutrophil and platelet engraftment was 17 and 37 days, respectively. Overall response rate was 68%; 58% achieved complete remission. Median progression-free survival (PFS) was 12.2 months; median overall survival was 27 months. Cumulative incidences of relapse and of non-relapse mortality at 5 years were 30% and 37.9%, respectively; 5-year PFS was 31.3% (95%CI 10.1-52.5). There was a trend toward inferior PFS in patients with lymph node size ≥2 cm at the time of alloSCT (p = 0.07) and toward inferior survival in patients with chemorefractory disease pre-alloSCT (p = 0.12). dUCBT is feasible in patients with heavily pre-treated HL and can achieve long-term disease-free survival in approximately 30% of patients. PMID:26472485

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. Modelling of crowded polymers elucidate effects of double-strand breaks in topological domains of bacterial chromosomes

    PubMed Central

    Dorier, Julien; Stasiak, Andrzej

    2013-01-01

    Using numerical simulations of pairs of long polymeric chains confined in microscopic cylinders, we investigate consequences of double-strand DNA breaks occurring in independent topological domains, such as these constituting bacterial chromosomes. Our simulations show a transition between segregated and mixed state upon linearization of one of the modelled topological domains. Our results explain how chromosomal organization into topological domains can fulfil two opposite conditions: (i) effectively repulse various loops from each other thus promoting chromosome separation and (ii) permit local DNA intermingling when one or more loops are broken and need to be repaired in a process that requires homology search between broken ends and their homologous sequences in closely positioned sister chromatid. PMID:23742906

  12. Nanoscale thickness double-gated field effect silicon sensors for sensitive pH detection in fluid

    SciTech Connect

    Elibol, Oguz H.; Reddy, Bobby Jr.; Bashir, Rashid

    2008-05-12

    In this work, we report on the optimization of a double-gate silicon-on-insulator field effect device operation to maximize pH sensitivity. The operating point can be fine tuned by independently biasing the fluid and the back gate of the device. Choosing the bias points such that device is nearly depleted results in an exponential current response--in our case, 0.70 decade per unit change in pH. This value is comparable to results obtained with devices that have been further scaled in width, reported at the forefront of the field, and close to the ideal value of 1 decade/pH. By using a thin active area, sensitivity is increased due to increased coupling between the two conducting surfaces of the devices.

  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. Absorption of terahertz radiation by plasmon modes in a grid-gated double-quantum-well field-effect transistor

    NASA Astrophysics Data System (ADS)

    Popov, V. V.; Polischuk, O. V.; Teperik, T. V.; Peralta, X. G.; Allen, S. J.; Horing, N. J. M.; Wanke, M. C.

    2003-09-01

    The terahertz absorption spectrum of plasmon modes in a grid-gated double-quantum-well (DQW) field-effect transistor structure is analyzed theoretically and numerically using a first principles electromagnetic approach and is shown to faithfully reproduce important physical features of recent experimental observations. We find that the essential character of the response—multiple resonances corresponding to spatial harmonics of standing plasmons under the metal grating—is caused by the static spatial modulation of electron density in the channel. Higher order plasmon modes become more optically active as the depth of the electron density modulation in the DQW tends towards unity. The maximum absorbance, at plasma resonance, is shown to be 1/2. Furthermore, the strongest absorption also occurs when the standing plasmon resonance coincides with the fundamental dipole mode of the ungated portion of the channel.

  15. 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.

  16. Effect of mixed convection and u-bends on the design of double-pipe heat exchangers

    SciTech Connect

    Abdelmessih, A.N.; Bell, K.J.

    1999-09-01

    For horizontal flow in the laminar flow regimen, the interaction between natural and forced convection and the effect of the secondary flow induced by an unheated U-bend were considered in developing an empirical correlation for the nearly uniform heat flux condition. The correlation predicts the local peripheral average heat transfer coefficient with an absolute average deviation of 9.9%. In this article the mechanisms involved in laminar flow with the presence of a U-bend are explained. The realistic behavior of the correlation is illustrated. Also, a brief discussion of some of the existing correlations for laminar flow is presented. Four cases showing the practicality of using the correlation in the design of horizontal double-pipe heat exchangers are demonstrated.

  17. Development of a double-effect air conditioner-heater (deach) phase 2. Final report, January 1989-December 1989

    SciTech Connect

    De Vuono, A.C.; Landstrom, D.K.; Osborne, R.L.; Christensen, R.N.; Flanigan, L.

    1992-12-01

    The report describes the results of Phase II of a multi-phase project to develop a high-efficiency, gas-fired, residential size air-conditioner/heater based on a double-effect, absorption cycle using LiBr and water as working fluids. The results discussed include experimental and analytical analysis of various options for key components and subsystems including absorber, direct expansion evaporator, solution heat exchangers and burner/generator subsystem. The thermodynamic model used to evaluate various system design tradeoffs is also discussed. The results of the Phase II effort provided the basis for full-scale, integrated breadboard testing to be conducted in Phase III of the project.

  18. 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.

  19. 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.

  20. 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